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Telomere Shortening During Aging; Attenuation by Antioxidants and Anti-inflammatory Agents
Abstract
Telomeres are a repeated sequence -of bases found at the ends of chromosomes. In humans, this sequence is TTAGGG, which is repeated over 2000 times. Telomeres protect the ends chromosomes from fusion with nearby chromosomes, and allow effective replication of DNA. Each time a cell divides, 25–200 base pairs are lost from the terminal sequence of chromosomes. By becoming truncated during cell division, telomeres protect essential genes from being shortened and thus inactivated. In addition, telomeres are sensitive to inflammation and oxidative stress, which can further promote telomere shortening. Reduction in the length of telomeres leads to the cessation of cell division and thus cellular senescence and apoptosis. This review discusses evidence for the role of oxidative stress and inflammation in regulating the length of telomeres in mammalian cells during senescence. Evidence is presented suggesting that antioxidants and anti-inflammatories can reduce the pace of shortening of telomere length during aging. The distinctive properties of transformed cells suggest that treatment with such materials will have a deleterious rather than a protective effect on such abnormal cells.
... Telomerase is composed of two subunits: a functional catalytic protein subunit called human telomerase reverse transcriptase (hTERT); and an RNA component known as human telomerase RNA component (hTERC) (Hannen & Bartsch, 2018;Leão et al., 2018). In combination with other telomerase components, hTERT helps to modulate cell survival and proliferation through telomerase-dependent telomere lengthening (Li et al., 2019;Prasad et al., 2017;Sugarman et al., 2019). hTERT also acts in a telomerase-independent fashion through intermolecular interactions, specifically involving TP53 (p53) and poly(ADP-ribose) polymerase (PARP) (Sugarman et al., 2019). ...
... Indeed, telomeres are preferential targets of oxidative stress due to their high content of guanine residues and the relative inefficiency of their DNA damage repair (Ahmed & Lingner, 2018; Li et al., 2019). Substantial evidence indicated that increased oxidative stress and inflammation play a central role in shortening the telomeres' length, possibly decreasing telomerase activity or TRF-2 level (Prasad et al., 2017). However, the mechanisms of oxidative stress-induced shortening of the size of telomere are not totally elucidated (Prasad et al., 2017). ...
... Substantial evidence indicated that increased oxidative stress and inflammation play a central role in shortening the telomeres' length, possibly decreasing telomerase activity or TRF-2 level (Prasad et al., 2017). However, the mechanisms of oxidative stress-induced shortening of the size of telomere are not totally elucidated (Prasad et al., 2017). Studies suggest that telomere attrition is modifiable, as substantial variability exists in the telomere shortening rate (Crous-Bou et al., 2019). ...
... Finally, a sensitivity analysis was conducted to assess the significant findings' robustness making a set of assumptions by using variables that could likely be related to either TL or child neuropsychological function [46][47][48][49][50][51][52]. First, we examined the effect of the mother's verbal reasoning (measured by the similarities test of the Wechsler Adult Intelligence Scale III) and different child's lifestyles, such as oily fish consumption (grams), television watching (hours per week), and sleep duration (hours per day) separately as a further adjustment to the main model. ...
... At the neurobiological level, this association is supported by the fact that inflammation processes were found to cause changes in neural circuitry, neurotransmitter activity, the neuroendocrine system and neurogenesis, impacting brain function and, by extension, cognitive functions [47,48,58,59]. Moreover, it should be noted that TL attrition has also been associated with inflammation events, including higher body mass index or biomarkers such as C-reactive protein [50], suggesting that inflammatory events might involve an interplay between telomeric dysfunction and poor cognitive functioning. ...
Shortened telomere length (TL) has been associated with lower cognitive performance, different neurological diseases in adults, and certain neurodevelopmental disorders in children. However, the evidence about the association between TL and neuropsychological developmental outcomes in children from the general population is scarce. Therefore, this study aimed to explore the association between TL and neuropsychological function in children 4–5 years of age. We included 686 children from the INMA Project, a population-based birth cohort in Spain. Leucocyte TL was determined by quantitative PCR method, and neuropsychological outcomes were measured using the McCarthy Scales of Children’s Abilities (MCSA). Multiple linear regression models were used to estimate associations adjusted for potential confounding variables. Main findings showed that a longer TL was associated with a higher mean working memory score (β = 4.55; 95% CI = 0.39, 8.71). In addition, longer TL was associated with a higher mean global quantitative score (β = 3.85; 95% CI = −0.19, 7.89), although the association was marginally significant. To our knowledge, this is the first study that shows a positive association between TL and better neuropsychological outcomes in children. Although further research is required to confirm these results, this study supports the hypothesis that TL is essential in protecting and maintaining a child’s health, including cognitive functions such as working memory.
... Telomerase is responsible for maintaining telomere length (TL) by synthesizing TTAGGG repeats at the end (Blackburn, 2001). Some base pairs are normally lost from the terminal region of chromosomes during each cell division (Prasad et al., 2017). Therefore, TL has been used as a common biomarker of aging. ...
... In animal models, shortened or lengthened telomeres mean decreased or increased lifespan of mice, respectively (Armanios et al., 2009). Shortened telomeres may lead to the cessation of cell division, thus promoting cellular senescence and apoptosis (Prasad et al., 2017). Meanwhile, shortened telomeres are more sensitive to systematic inflammation and oxidative stress, which can further promote aging (Masi et al., 2011). ...
Several studies have assessed the effects of intermittent hypoxia-normoxia training (IHNT), intermittent hypoxia-hyperoxia training (IHHT), and obstructive sleep apnea (OSA) on aging and age-related diseases in humans; however, the results remain contradictory. Therefore, this review aims to systematically summarize the available studies on the effects of IHNT, IHHT, and OSA on aging and age-related diseases. Relevant studies were searched from PubMed, Google Scholar, Cochrane Library databases, and through manual searching from reference lists of eligible studies. A total of 38 eligible studies were included in this systematic review. IHHT and IHNT provide positive effects on several age-related parameters including quality of life, cognitive and physical functions, plasma level of glucose and cholesterol/LDL, systolic blood pressure, red blood cells, and inflammation. Moreover, moderate intermittent hypoxia induces telomerase reverse transcriptase (TERT) activity and telomere stabilization, delays induction of senescence-associated markers expression and senescence-associated β-galactosidase, upregulates pluripotent marker (Oct4), activates a metabolic shift, and raises resistance to pro-apoptotic stimuli. On the contrary, intermittent hypoxia in OSA causes hypertension, metabolic syndrome, vascular function impairment, quality of life and cognitive scores reduction, advanced brain aging, increase in insulin resistance, plasma hydrogen peroxide, GSH, IL-6, hsCRP, leptin, and leukocyte telomere shortening. Thus, it can be speculated that the main factor that determines the direction of the intermittent hypoxia action is the intensity and duration of exposure. There is no direct study to prove that IHNT/IHHT actually increases life expectancy in humans. Therefore, further study is needed to investigate the actual effect of IHNT/IHHT on aging in humans.
Systematic Review Registration
www.crd.york.ac.uk/prospero , identifier CRD42022298499.
... Aspirin, also known as acetylsalicylic acid, is a widely used nonsteroidal anti-inflammatory drug (NSAID) for reducing pain, fever, and inflammation. Numerous other health benefits have been reported for aspirin, including for cancer and age-related diseases, leading to its reputation as a "magic" medicine molecule [1][2][3] . As its chemical structure indicates, aspirin is a potent acetylating agent that induces acetylation on substrates such as cyclooxygenases, which are believed to be involved in the drug's primary anti-inflammatory mechanism of action 4 . ...
Aspirin is a potent lysine acetylation inducer, but its impact on lysine ubiquitination and ubiquitination-directed protein degradation is unclear. Herein, we develop the reversed-pulsed-SILAC strategy to systematically profile protein degradome in response to aspirin. By integrating degradome, acetylome, and ubiquitinome analyses, we show that aspirin impairs proteasome activity to inhibit proteasomal degradation, rather than directly suppressing lysine ubiquitination. Interestingly, aspirin increases lysosomal degradation-implicated K63-linked ubiquitination. Accordingly, using the major pathological protein of Parkinson’s disease (PD), α-synuclein (α-syn), as an example of protein aggregates, we find that aspirin is able to reduce α-syn in cultured cells, neurons, and PD model mice with rescued locomotor ability. We further reveal that the α-syn aggregate clearance induced by aspirin is K63-ubiquitination dependent in both cells and PD mice. These findings suggest two complementary mechanisms by which aspirin regulates the degradation of soluble and insoluble proteins, providing insights into its diverse pharmacological effects that can aid in future drug development efforts.
... Telomerase reverse transcriptase (TERT) is the catalytic subunit of the enzyme telomerase responsible for telomere length maintenance [20,21]. TERT is an important cancer hallmark [22], primarily known for maintaining telomere length by preventing cellular senescence and ensuring immortality [23], but it also has telomere-independent roles responsible for tumor progression. ...
Background/Objectives: Telomerase reverse transcriptase (TERT) is the catalytic subunit of the telomerase enzyme responsible for telomere length maintenance and is an important cancer hallmark. Our study aimed to clarify the mRNA expression of TERT in peritoneal mesothelioma (PeM), and to explore the relationship between its expression and the clinicopathological parameters and prognosis of patients with PeM. Methods: In a cohort of 13 MpeM patients, we evaluated histotype, nuclear grade, mitotic count, necrosis, inflammation, Ki67, BAP1, MTAP and p16 expression by immunohistochemistry, p16/CDKN2A status by FISH and TERT mRNA expression by RNAscope. Results: Our results showed several statistical correlations between TERT mRNA-score and other investigated features: (i) a poor positive correlation with BAP1 score (r = 0.06340; p ≤ 0.0001); (ii) a moderate positive correlation with p16 FISH del homo (r = 0.6340; p ≤ 0.0001); (iii) a fair negative correlation with p16 FISH del hetero (r = −0.3965; p ≤ 0.0001); a negative poor correlation with MTAP (r = −0.2443; p ≤ 0.0001); and (iv) a negative fair correlation with inflammatory infiltrate (r = −0.5407; p = 0.0233). Moreover, patients survive for a significantly longer time if they have a low mitotic index adjusted (2–4 mitotic figures per 2 mm²) (p ≤ 0.0001), are male (p = 0.0152), lose BAP1 (p = 0.0152), are p16 positive and present no deletion or heterozygous for p16 (p ≤ 0.01). Conclusions: TERT is highly expressed in PeM, but it is not one of the crucial factors in evaluating the prognosis of patients. Nevertheless, the results validate the prognostic significance of the mitotic index, BAP1 loss and p16/CDKN2A status.
... As a critical cellular energy sensor, AMPK is involved in various signaling pathways that the detailed mechanism on how AMPK regulates telomere function in different systems require future extensive study. We cannot rule out the possibility that AMPK regulates telomere function through SIRT1 signaling, tightly related to telomere maintenance [56], and through its anti-inflammatory effect since telomeres are sensitive to inflammation [57]. High levels of gut-derived endotoxins and chronic inflammation were clinically linked to telomere shortening [58], potentially accounting for vascular telomere dysfunction upon age-associated dysbiosis. ...
Aging, an independent risk factor for cardiometabolic diseases, refers to a progressive deterioration in physiological function, characterized by 12 established hallmarks. Vascular aging is driven by endothelial dysfunction, telomere dysfunction, oxidative stress, and vascular inflammation. This study investigated whether aged gut microbiome promotes vascular aging and metabolic impairment. Fecal microbiome transfer (FMT) was conducted from aged (>75 weeks old) to young C57BL/6 mice (8 weeks old) for 6 weeks. Wire myography was used to evaluate endothelial function in aortas and mesenteric arteries. ROS levels were measured by dihydroethidium (DHE) staining and lucigenin-enhanced chemiluminescence. Vascular and intestinal telomere function, in terms of relative telomere length, telomerase reverse transcriptase expression and telomerase activity, were measured. Systemic inflammation, endotoxemia and intestinal integrity of mice were assessed. Gut microbiome profiles were studied by 16S rRNA sequencing. Some middle-aged mice (40–42 weeks old) were subjected to chronic metformin treatment and exercise training for 4 weeks to evaluate their anti-aging benefits. Six-week FMT impaired glucose homeostasis and caused vascular dysfunction in aortas and mesenteric arteries in young mice. FMT triggered vascular inflammation and oxidative stress, along with declined telomerase activity and shorter telomere length in aortas. Additionally, FMT impaired intestinal integrity, and triggered AMPK inactivation and telomere dysfunction in intestines, potentially attributed to the altered gut microbial profiles. Metformin treatment and moderate exercise improved integrity, AMPK activation and telomere function in mouse intestines. Our data highlight aged microbiome as a mechanism that accelerates intestinal and vascular aging, suggesting the gut-vascular connection as a potential intervention target against cardiovascular aging and complications.
... Specifically, inflammatory can accelerate telomere shortening by promoting oxidative stress, DNA damage, and increased cell turnover [1047]. Chronic inflammation also leads to the activation of immune cells releasing of pro-inflammatory cytokines and ROS, all of which contribute to telomere attrition [1047][1048][1049]. Additionally, inflammatory processes can upregulate telomerase activity, which not only compensates for telomere shortening, but also contribute to the survival and proliferation of cancer cells [1050]. ...
Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location’s importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma–carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.
... The observed positive effects of quercetin on TL could be attributed to various, interrelated mechanistic reasons with yet unresolved intricacies and primarily to its capacity for mitigating oxidative stress and inflammation [35][36][37], both of which are known to accelerate TS [75,76]. This antioxidant protection potentially enables enhanced telomerase stability [3,77]. ...
Telomeres, the protective chromosomal ends, progressively shorten and potentially are implicated in the pathogenesis of age-related diseases. In type 2 diabetes (T2DM), telomere shortening may play an important role, but the whole ‘picture’ remains limited. From a therapeutic perspective, the phytonutrient quercetin appears to be clinically effective and safe for patients with T2DM. Considering the above, we aimed to examine whether quercetin could interfere with telomere length (TL) dynamics. One hundred patients with T2DM on non-insulin medications registered within a primary healthcare facility were stratified by age and sex and randomly assigned to either standard care or standard care plus quercetin (500 mg/day) for 12 weeks, succeeded by an 8-week washout period and another 12 weeks of supplementation. Of the 88 patients completing the trial, 82 consented to blood sampling for TL measurements. Health assessments and whole blood absolute TL measurements using quantitative polymerase chain reaction (qPCR) were conducted at baseline and study end, and the findings of this subcohort are presented. Quercetin supplementation was associated with a significant increase in mean TL (odds ratio ≥ 2.44; p < 0.05) with a strengthened association after full adjustment for potential confounders through multiple logistic regression analysis (odds ratio = 3.48; p = 0.026), suggesting it as a potentially promising supplementation option. Further studies are needed to confirm this finding, elucidating the underlying molecular mechanisms of quercetin.
... A physiological response to this damage to the DNA strands and a loss of cell proliferation are triggered, resulting in senescence and/or apoptosis (Herrmann et al, 2018;Turner et al, 2019). The shortening of the ends of DNA strands can also be conditioned by epigenetic and genetic factors, and by parameters such as age, sex, body fat, inflammation, socioeconomic factors, ethnicity, and PA level (Herrmann et al, 2018;Turner et al, 2019;Prasad et al, 2017). In fact, many manuscripts have proven how physical exercise can play a significant role in improving genomic stability. ...
Dozens of data prove that the DNA damage accumulates during human aging and that lifestyle factors contribute to the accumulation of DNA alteration. Telomeres are nucleoprotein complexes located at the ends of chromosomes, serving to protect DNA integrity by acting as caps. Telomere length decreases with age, which promotes cell senescence. Shortened telomeres accelerate aging and can lead to cells apoptosis. Telomere shortening is associated with biological aging and can be influenced by factors such as inflammation and oxidative stress. Recent evidence supports that telomere length of skeletal muscle cells and leukocytes may be positively associated with healthy living and inversely correlated with the risk of age-related syndromes, including obesity, cancer, chronic pain, diabetes, cardiovascular disease, and stress. In this paper, recent studies are summarized to examine the possible influence of exercise on telomere length. Higher levels of exercise or physical activity are related to longer telomere lengths in several populations, and athletes tend to have longer telomere lengths than non-athletes. This relationship is particularly clear in older individuals, proposing a role of physical activity in preventing the typical age-induced decrements in telomere length. It is proposed that physical activity has a positive effect on the rate of telomere length shortening. In particular, the athletes tend to have longer telomere than sedentary individuals. Exercise has a beneficial outcome on telomere length compared with usual care or inactivity. The evidence gathered to date shows that especially aerobic exercise slows the decline in telomere length. It is fundamental to emphasize how this is important not to overdo it, that is, overtraining must be avoided. Anyway, physical activity and exercise can have both restorative and protective effects and, as such, show great probable to improve well-being and increase longevity. Future studies is needed to mechanistically examine the properties of diverse modalities of exercise on telomere length in middle-aged and older subjects.
... The results of the MR analysis indicate a positive causal relationship between disorders of mineral metabolism and TL, but no significant relationship between disorders of mineral metabolism and mtDNA-CN. In light of the fact that TL is an indicator of cellular aging [50,51], these findings suggest that an increase in disorders of mineral metabolism may contribute to the maintenance of TL, thereby influencing the aging process and potentially increasing vulnerability to diseases associated with TL prolongation. This finding underscores the significance of mineral metabolism in preserving optimal TLs and retarding the aging process. ...
The aim of this study was to assess the causal relationships between mineral metabolism disorders, representative of trace elements, and key aging biomarkers: telomere length (TL) and mitochondrial DNA copy number (mtDNA-CN). Utilizing bidirectional Mendelian randomization (MR) analysis in combination with the two-stage least squares (2SLS) method, we explored the causal relationships between mineral metabolism disorders and these aging indicators. Sensitivity analysis can be used to determine the reliability and robustness of the research results. The results confirmed that a positive causal relationship was observed between mineral metabolism disorders and TL (p < 0.05), while the causal relationship with mtDNA-CN was not significant (p > 0.05). Focusing on subgroup analyses of specific minerals, our findings indicated a distinct positive causal relationship between iron metabolism disorders and both TL and mtDNA-CN (p < 0.05). In contrast, disorders in magnesium and phosphorus metabolism did not exhibit significant causal effects on either aging biomarker (p > 0.05). Moreover, reverse MR analysis did not reveal any significant causal effects of TL and mtDNA-CN on mineral metabolism disorders (p > 0.05). The combination of 2SLS with MR analysis further reinforced the positive causal relationship between iron levels and both TL and mtDNA-CN (p < 0.05). Notably, the sensitivity analysis did not indicate significant pleiotropy or heterogeneity within these causal relationships (p > 0.05). These findings highlight the pivotal role of iron metabolism in cellular aging, particularly in regulating TL and sustaining mtDNA-CN, offering new insights into how mineral metabolism disorders influence aging biomarkers. Our research underscores the importance of trace element balance, especially regarding iron intake, in combating the aging process. This provides a potential strategy for slowing aging through the adjustment of trace element intake, laying the groundwork for future research into the relationship between trace elements and healthy aging.
... 35 Evidence suggests that antioxidants and antiinflammatories can reduce the pace of shortening of telomere length during aging. 36 Shin C et. at. suggested that with low-grade inflammation along with moderately elevated serum homocysteine (HCY) levels may influence the attrition of leukocyte telomere length (LTL) in older adults. ...
Aging is a universal, inherent, natural phenomenon that occurs in all organism. Aging involves morphologicaland functional changes in cellular and extracellular components leading to progressive decline in mostbiological functions. It causes reduction in strength, basal metabolism, sexual activity and the body’sdefenses.Aging is the progressive decline in the maintenance of homeostasis, which leads to decreased response ofthe body against internal and external stress. It involves imbalance between free radicals and the antioxidantmechanism lead to damaged cells, tissues, and organs resulting in age related changes.With age there is modifications in energy metabolism, insulin sensitivity, neuroendocrine function andinduction of hormesis response. Telomere shortening, mitochondrial dysfunction, increase of oxidativestress, alteration of insulin-like growth factor and growth hormone signaling are considered to be importantcontributors of aging process.Recently many genes and changes in gene expression have been found associated with aging which affectsmany biological processes and are associated with senescence and oxidative stress.This review focuses on the underlying mechanism of biological aging. With an increase in the number ofelderly population and the patients of age-related diseases, it is becoming increasingly important to considerthese in the field of research. We have attempted to discuss the different aging mechanism along with thenewer concepts, which can give a direction for the future research studies.
... This was particularly significant because shorter telomeres were linked to cellular malfunction, senescence, and an increased susceptibility to age-related ailments [38][39][40]. Antioxidants had been found to exert an effect on signaling pathways implicated in the aging process and age-related ailments [41]. Specifically, certain antioxidants had been demonstrated to stimulate sirtuins, a group of proteins that oversee a range of cellular functions associated with aging, such as DNA restoration and metabolic processes [42][43][44]. ...
Objective:
The objective of this study was to explore the potential correlation between the composite dietary antioxidant index (CDAI) and biological aging, addressing the insufficient epidemiological evidence in this area.
Methods:
Participants meeting eligibility criteria were selected from the National Health and Nutrition Examination Surveys (NHANES) conducted between 2001 and 2018. CDAI was determined based on dietary antioxidants obtained from 24-hour dietary recalls. Biological age was determined using PhenoAge algorithms incorporating various clinical features. Weighted multiple models were employed to investigate and assess the association between CDAI and biological age.
Results:
Analysis of the CDAI quartile revealed disparities in terms of age, gender, ethnicity, educational level, marital status, poverty, dietary calories intakes, smoking, drinking status, BMI, physical activity, and PhenoAge. After adjusting for potential confounding factors, a significant inverse relationship was found between CDAI and Phenotypic Age, with each standard deviation increase in CDAI score correlating with a 0.18-year decrease in Phenotypic Age. These negative correlations between CDAI and PhenoAge advancement were observed regardless of age, gender, physical activity status, smoking status, and body mass index.
Conclusions:
Our findings demonstrate a positive relationship between higher CDAI scores and delayed biological aging. These results have significant implications for public health initiatives aimed at promoting healthy aging through dietary interventions.
... When telomeres get too short, cells go through a process called senescence, which involves the release of pro-inflammatory chemicals and the permanent halting of cell division [34,35]. Cellular senescence is thought to contribute to various age-related pathologies, including osteoarthritis, atherosclerosis, and frailty [22,36,37]. Thus, the link between shorter LTL and mortality in MetS patients could, in part, be mediated by the induction of cellular senescence. ...
Background
The relationship between leukocyte telomere length (LTL) and mortality risk in individuals with metabolic syndrome (MetS) remains poorly understood. This study aimed to investigate the association between telomere length and long-term all-cause mortality, and cardiovascular disease (CVD) mortality, in individuals with MetS in the United States.
Methods
A total of 1980 participants with MetS aged 18 years or older from the National Health and Nutrition Examination Survey (NHANES) prospective cohort study (1999–2002) were included in this cohort study. Medical records review was used to identify the cause of deaths as of December 2018. We employed Kaplan-Meier curves, fitted curves, and Cox proportional hazards regression models to estimate hazard ratios (HRs) for all-cause and CVD mortality, stratified by tertiles of LTL.
Results
Over a median follow-up of 17.75 years of participants with metabolic syndrome, 819 deaths occurred, including 231 cardiovascular deaths. After adjusting for multiple covariates, participants with shorter telomere length had a significantly higher risk of all-cause mortality (HR, 1.33; 95% CI, 1.11–1.6) and CVD mortality (HR, 1.36; 95% CI, 0.96–1.93) compared with those in the highest tertile of telomere length. All-cause mortality (P < 0.001) and cardiovascular disease mortality (P = 0.028) followed a similar pattern across tertiles of telomere length.
Conclusion
In individuals with MetS, shorter telomere length is associated with increased risks of death from cardiovascular disease and all causes. The underlying mechanisms and clinical implications of these findings require additional investigation.
... Telomerase is used for the treatment of age-related diseases and telomeropathies [15]. Also, antiinflammatory agents and antioxidants can find application to slow telomere length loss [16]. ...
Aging is a biological event that influences many organs and systems. Both sarcopenia and frailty syndrome refer to geriatric conditions with overlapping phenotypes. Many mechanisms are involved in the aging process such as DNA methylation telomeres which are susceptible to oxidative stress, and inflammations which result in telomere shortening, leading to chromosomal instability. The study aimed to determine the associations between these processes, frailty and sarcopenia syndrome. Global DNA methylation was analyzed using the ELISA method. Telomere length was analyzed using qPCR. Total oxidative status (TOS) was analyzed using a colorimetric method. The present study revealed that the main factor affecting methylation, telomeres length and level of total oxidant stress was age.
... Since cellular aging seems to be caused by the molecular alterations induced by ROS and the consequent dysfunctions, it has been hypothesized that antioxidant substances capable of effectively extinguishing various forms of ROS or of reducing their production, especially in the mitochondria, can slow down the speed of aging and reduce the incidence of age-related diseases [16]. On this assumption, numerous studies have been conducted aimed at estimating the effects of levels of endogenous antioxidants or the effect of the administration of exogenous antioxidants on aging and on age-related processes and diseases [17,18]. Until now, the outcomes of the effects of the administration of single or multiple antioxidants on the age-related decline of brain functions have been inconclusive, and other studies are necessary to define the efficacy of antioxidant supplementation [17]. ...
Aerobic organisms use molecular oxygen in several reactions, including those in which the oxidation of substrate molecules is coupled to oxygen reduction to produce large amounts of metabolic energy. The utilization of oxygen is associated with the production of ROS, which can damage biological macromolecules but also act as signaling molecules, regulating numerous cellular processes. Mitochondria are the cellular sites where most of the metabolic energy is produced and perform numerous physiological functions by acting as regulatory hubs of cellular metabolism. They retain the remnants of their bacterial ancestors, including an independent genome that encodes part of their protein equipment; they have an accurate quality control system; and control of cellular functions also depends on communication with the nucleus. During aging, mitochondria can undergo dysfunctions, some of which are mediated by ROS. In this review, after a description of how aging affects the mitochondrial quality and quality control system and the involvement of mitochondria in inflammation, we report information on how vitamin E, the main fat-soluble antioxidant, can protect mitochondria from age-related changes. The information in this regard is scarce and limited to some tissues and some aspects of mitochondrial alterations in aging. Improving knowledge of the effects of vitamin E on aging is essential to defining an optimal strategy for healthy aging.
... In addition, an unhealthy lifestyle and behavioral habits such as smoking, alcohol consumption, nutrition and obesity can increase ROS production and negatively affect the STL [22,[56][57][58][59]. In this study, no information regarding the possible exposure of men to ROS was available. ...
Male factors are suspected in around half cases of infertility, of which up to 40% are diagnosed as idiopathic. In the context of a continuously increased resort to ART and increased decline of semen parameters, it is of greatest interest to evaluate an additional potential biomarker of sperm quality. According to PRISMA guidelines, this systematic review of the literature selected studies evaluating telomere length in sperm and/or in leukocytes as a potential male fertility biomarker. Twenty-two publications (3168 participants) were included in this review of experimental evidence. For each study, authors determined if there was a correlation between telomere length and semen parameters or fertility outcomes. Of the 13 studies concerning sperm telomere length (STL) and semen parameters, ten found an association between short STL and altered parameters. Concerning the impact of STL on ART results, the data are conflicting. However, eight of the 13 included studies about fertility found significantly longer sperm telomeres in fertile men than in infertile men. In leukocytes, the seven studies reported conflicting findings. Shorter sperm telomeres appear to be associated with altered semen parameters or male infertility. Telomere length may be considered as a new molecular marker of spermatogenesis and sperm quality, and thus is related to male fertility potential. However, additional studies are needed to define the place of the STL in the assessment of individual fertility.
... At the organismal level, individuals with higher exposure to oxidative stress have increased telomere loss (Glade & Meguid, 2015), and circulating ROS have been correlated with telomere loss in red blood cells of king penguin chicks (Aptenodytes patagonicus). The administration of antioxidant molecules is able to counteract these effects: indeed, this has been observed in cell cultures, and in whole organisms when antioxidants were administered by diet (Badás et al., 2015;Prasad et al., 2017). In rats born from undernourished mothers, the administration of ubiquinone by diet prevented telomere shortening in the aorta and the heart tissues (Tarry-Adkins et al., 2013). ...
Genomes are progressively modified during their evolution leading to gene content variation, recombination, mutation and genetic exchange among species/subpopulations. The advent of next-generation sequencing technologies and their cost reduction increased the number of genomes available for evolutionary studies, opening the way to understand the molecular mechanisms involved in genome evolution. In this work, I used the budding yeast Saccharomyces cerevisiae as model organism to investigate two important aspects of genome evolution: the origin of interspecies introgressions and telomere evolution.An introgression is the flow of genetic material between populations and it results from ancient hybridization events followed by repeated backcrossings with one of the parental populations. In the first part of my PhD, I studied a lineage of S. cerevisiae strains isolated from the wastewater of olive oil production (Alpechin), carrying abundant introgressions from the sister species S. paradoxus, and a natural S. cerevisiae/S. paradoxus hybrid, with 50% genome contribution from each parent, carrying abundant regions of loss-of-heterozygosity (LOH). I derived an accurate genetic map of LOHs in the hybrid and compared their position to the introgressions in the Alpechin strains, to infer their evolutionary relations. I found that LOH and introgressions overlapped and shared the same S. paradoxus ancestry, indicating that LOHs are the direct origins of introgressions in the Alpechin lineage. I proposed a model for the origin of yeast introgressions in which LOH regions allow interspecies hybrids to overcome sterility, which constitutes the main barrier to introgressions' onset in reproductively isolated species, such as yeasts, and validated the reliability of my model using experimental and computational techniques.In the second part of my PhD, I studied the extent of telomere diversity in S. cerevisiae and the outcome of chronic telomeric stress on cellular fitness. In a first project, I estimated telomere length in over 900 strains isolated around the world and observed remarkable variation. Strains isolated in wild habitats had shorter telomeres than domesticated ones. I performed a genome-wide association study that revealed novel genetic variants possibly regulating telomere length. I also pinpointed private loss-of-function mutations in known telomere length maintenance genes that could explain the very long/short telomeres of certain lineages. Moreover, I used multiple phenotypic datasets available for this collection to look for non-genetic factors associated to telomere length variation, and discovered an association between mitochondrial metabolism and telomeres in wild strains.In a second project, I performed experimental evolution of engineered yeasts synthetizing human telomeric DNA repeats at their chromosome-ends. I evolved telomere-humanized strains through mutation accumulation lines (MALs) to minimize selection, and I characterized the detrimental effects caused by telomeres' reshaping. During MALs, humanized yeasts gradually slowed their growth, shortened chronological lifespan and had higher mutation rate and genome instability. Next, I submitted MALs to adaptive evolution by multiple serial transfers (STs) of large population sizes, to map mutations that counteract their fitness decline. After multiple STs, most humanized lines recovered fitness thanks to the independent occurrence of mutations in the DNA-damage response pathway. Overall, my work contributed to elucidate the molecular mechanisms driving genome evolution, by providing a plausible model for introgression evolution in reproductively isolated species and by giving an unprecedented overview of the impact of the variation of telomere DNA length and sequence on global organismal fitness.
... Presently, a shift from the traditional Okinawa diet to a high fat and protein diets is experienced due to modernization [18], This has led to increase free radical cell damage and older adults are mostly in danger of increased inflammation and decreased cellmediated immune response, which is fundamentally impacted by nutritional status [19,20]. Research suggests that foods rich in antioxidants may prevent free radical cell damage, inflammation and also slow aging [21]. A decrease in metabolic rate is seen as one gets older because of the decline in lean mass with a decrease in protein moieties, connective tissues, collagen, immune cells and transporters. ...
Aging may be linked to the onset of diseases, thus more emphasis should be put on our well being as we age. Staying youthful and healthy as we age relies on changes in our way of life, which includes; indulging in physical activities, emotional wellbeing and more importantly nutrition. A healthy eating regimen has to do with the preparation of food and storage that preserves the nutrients. A decent diet ought to contain sufficient amount of carbohydrates, fats and proteins with the recommended daily amounts of every basic minerals and vitamins. An individual's hereditary constitution may determine response to available nutrition, therefore, it is important that the overall aging population know about what sufficient nourishment entails. In spite of the fact that those in danger of deficient nutrition are from the developed and developing societies, the education of older adults on the importance of nutrition and nutrition intervention programs will aid in averting under nutrition.
... The shorter LTL group comprised of offspring with lower Matsuda index and higher HOMA-IR, and at the same time, these offspring were observed to have greater insulin release during an OGTT and higher insulinogenic index and beta-cell function. Both increased cellular oxidative stress [34] and active pancreatic cell division, which are key factors interacting with the telomere [12], may have contributed to the shorter LTL. The fact that oral disposition index (oDI), the only dynamic measure of beta-cell function which controls for prevailing insulin resistance, was not associated with children's LTL, despite the many associations between pancreatic traits and children's LTL, may suggest the associations of LTL with beta-cell function were perhaps driven by the association between LTL and insulin resistance. ...
Background
Leukocyte telomere length (LTL) is suggested to be a biomarker of biological age and reported to be associated with metabolic diseases such as type 2 diabetes. Glucose metabolic traits including glucose and insulin levels have been reported to be associated with LTL in adulthood. However, there is relatively little research focusing on children’s LTL and the association with prenatal exposures. This study investigates the relationship between maternal and offspring glucose metabolism with offspring LTL in early life.
Methods
This study included 882 mother-child pairs from the HAPO Hong Kong Field Centre, with children evaluated at age 7.0 ± 0.4 (mean ± SD) years. Glucose metabolic traits including maternal post-load glucose during pregnancy, children’s glucose and insulin levels, and their derived indices at follow-up were measured or calculated. Offspring LTL was assessed using real-time polymerase chain reaction.
Results
Sex- and age-adjusted children’s LTL was found to be associated with children’s HOMA-IR (β=−0.046 ± 0.016, p=0.005). Interestingly, both children’s and maternal post-load glucose levels were positively associated with children’s LTL. However, negative associations were observed between children’s LTL and children’s OGTT insulin levels. In addition, the LTL in females was more strongly associated with pancreatic beta-cell function whilst LTL in males was more strongly associated with OGTT glucose levels.
Conclusions
Our findings suggest a close association between maternal and offspring glucose metabolic traits with early life LTL, with the offspring sex as an important modifier of the disparate relationships in insulin production and response.
... Such lower inflammation and oxidative stress may retard telomere attrition (34,35). Through a similar mechanism, antioxidants (e.g., carotenoids and n-acetylcysteine) and anti-inflammatory agents (e.g., resveratrol, aspirin, and statins) also demonstrated a positive role in slowing the pace of telomere shortening (36). In addition, EPA and DHA intake may help increase the life span of normal cells through stabilizing membranes (e.g., increase of membrane fluidity) (37), decreasing polymorphonuclear chemotaxis and infiltration, increasing macrophage phagocytosis and efferocytosis and leukocyte egress, and clearing bacteria and apoptotic cells (38), reducing telomere attrition. ...
Background:
Omega-3 (n-3) and omega-6 (n-6) fatty acids may contribute to oxidative stress and inflammation, which are related to telomere shortening. Evidence supporting an association between intake of n-3 or n-6 fatty acids and leukocyte telomere length (LTL) in males has been limited.
Objective:
We conducted a cross-sectional study to examine the associations of total or individual n-3 or total n-6 fatty acid intake with LTL in US males.
Methods:
We included 2,494 US males with LTL measurement from 4 nested case-control studies within the Health Professionals Follow-up Study. Individuals with previous histories of cancers, diabetes, and cardiovascular diseases at or prior to blood collection were excluded. Blood collection was performed between 1993 and 1995, and relevant information including n-3 and n-6 intake was collected in 1994 by questionnaire. The LTL was log-transformed and Z scores of the LTL were calculated for statistical analyses by standardizing the LTL in comparison with the mean within each selected nested case-control study.
Results:
We found that consumption of docosahexaenoic acid (DHA) was positively associated with LTL. In the multivariable-adjusted model, compared to individuals who had the lowest intake of DHA (i.e., first quartile group), the percentage differences [95% confidence intervals (CIs)] of LTL were -3.7 (-13.7, 7.5), 7.0 (-4.3, 19.7), and 8.2 (-3.5, 21.3) for individuals in the second, third, and fourth quartiles of consumption, respectively (P for trend = 0.0498). We did not find significant associations between total n-3 or total n-6 fatty acid intakes and LTL. Additionally, we found that males who consumed canned tuna had longer LTL than those who did not; in the multivariable-adjusted model, the percentage difference (95% CI) of LTL was 10.5 (1.3, 20.4) (P value = 0.02).
Conclusions:
Our results suggest that higher intakes of DHA and canned tuna consumption are associated with longer LTL.
... Data on the relationship between telomere length and the use of aspirin, an antiinflammatory agent, and an antioxidant, are inconsistent and depend on the type of cell studied [122]. The effects of aspirin alone, EPA + DHA, and the combined effects of aspirin and EPA + DHA treatment on telomerase activity have been explored in a limited number of 30 adults with diabetes mellitus [99]. ...
Telomeres are complexes consisting of tandem repeat DNA combined with associated proteins that play a key role in protecting the ends of chromosomes and maintaining genome stability. They are considered a biological clock, as they shorten in parallel with aging. Furthermore, short telomeres are associated with several age-related diseases. However, the variability in telomere shortening independent of chronological age suggests that it is a modifiable factor. In fact, it is regulated inter alia by genetic damage, cell division, aging, oxidative stress, and inflammation. A key question remains: how can we prevent accelerated telomere attrition and subsequent premature replicative senescence? A number of studies have explored the possible impact of omega-3 fatty acids on telomere shortening. This review summarizes published cross-sectional studies, randomized controlled trials, and rodent studies investigating the role of omega-3 fatty acids in telomere biology. It also covers a broad overview of the mechanism, currently favored in the field, that explains the impact of omega-3 fatty acids on telomeres—the food compound’s ability to modulate oxidative stress and inflammation. Although the results of the studies performed to date are not consistent, the vast majority indicate a beneficial effect of omega-3 fatty acids on telomere length.
... Since ancient times, humans have shown considerable interest in extending their life spans, which has inspired many studies on the mechanism underlying the extension of the life span. Recent studies have demonstrated that the human life span is affected by inflammation, mitochondrial function, telomere length, and immune function [1][2][3][4]. Diabetes is a common disease among elderly adults, and its complications can lead to organ damage and shortening of the life span. Metformin is a first-line hypoglycemic drug that not only lowers blood glucose levels but also affects the human life span [5]. ...
Acarbose can extend the life span of mice through a process involving the gut microbiota. Several factors affect the life span, including mitochondrial function, cellular senescence, telomere length, immune function, and expression of longevity-related genes. In this review, the effects of acarbose-regulated gut microbiota on the life span-influencing factors have been discussed. In addition, a novel theoretical basis for improving our understanding of the mechanisms by which acarbose extends the life span of mice has been suggested.
... Dysfunctional telomeres, caused by telomere shortening, the collapse of telomere structure, or displacement of shelterin complexes from telomeres, trigger a DNA damage response and loss of cell proliferation leading to senescence or apoptosis [27,28,31]. In addition, telomere shortening can be influenced by genetic factors (e.g., TERT and TERC, genes important for telomeric maintenance), epigenetic factors, and other factors such as age, gender, body fat, ethnicity, inflammation, socioeconomic factors, and physical activity level [28,[32][33][34]. ...
Aging is a natural process of organism deterioration, which possibly impairs multiple physiological functions. These harmful effects are linked to an accumulation of somatic mutations, oxidative stress, low-grade inflammation, protein damage, and mitochondrial dysfunction. It is known that these factors are capable of inducing telomere shortening, as well as intestinal dysbiosis. Otherwise, among the biological mechanisms triggered by physical exercise, the attenuation of pro-inflammatory mediators accompanied by redox state improvement can be the main mediators for microbiota homeostasis and telomere wear prevention. Thus, this review highlights how oxidative stress, inflammation, telomere attrition, and gut microbiota (GM) dysbiosis are interconnected. Above all, we provide a logical foundation for unraveling the role of physical exercise in this process. Based on the studies summarized in this article, exercise training can increase the biodiversity of beneficial microbial species, decrease low-grade inflammation and improve oxidative metabolism, these factors together possibly reduce telomeric shortening.
... On the contrary, some interventions are being tested to prevent telomere attrition and treat telomere-driven diseases, such as antioxidants, non-acarbose antidiabetic agents (T2DM), and lithium (bipolar disorder) (82). However, this impact may not be desirable in malignant cells (87,88). So far, there is no underlying mechanism that completely explains the genesis and causes of telomere attrition in these diseases (89). ...
As research related to healthspan and lifespan has become a hot topic, the necessity for a reliable and practical biomarker of aging (BoA), which can provide information about mortality and morbidity risk, along with remaining life expectancy, has increased. The chromosome terminus non-coding protective structure that prevents genomic instability is called a telomere. The continual shortening of telomeres, which affects their structure as well as function, is a hallmark of agedness. The aforementioned process is a potential cause of age-related diseases (ARDs), leading to a bad prognosis and a low survival rate, which compromise health and longevity. Hence, studies scrutinizing the BoAs often include telomere length (TL) as a prospective candidate. The results of these studies suggest that TL measurement can only provide an approximate appraisal of the aging rate, and its implementation into clinical practice and routine use as a BoA has many limitations and challenges. Nevertheless, measuring TL while determining other biomarkers can be used to assess biological age. This review focuses on the importance of telomeres in health, senescence, and diseases, as well as on summarizing the results and conclusions of previous studies evaluating TL as a potential BoA.
... Furthermore, ROS promote 8-oxoguanine formation, a common DNA damage that causes mismatch pairing with adenine leading to G-to-T and C-to-A substitutions in the genome [125]. Finally, ROS also impair the repair of oxidative DNA damage via a decrease in endonuclease III-like protein 1, which recognizes and corrects base damage of pyrimidines [142]. In summary, the different types of oxidative DNA damage compromise the protective function of telomeres, trigger systemic inflammation, and drive cellular senescence through a senescence-associated secretory phenotype (SASP) [143]. ...
Plasma homocysteine (HCY) is an established risk factor for cardiovascular disease CVD and stroke. However, more than two decades of intensive research activities has failed to demonstrate that Hcy lowering through B-vitamin supplementation results in a reduction in CVD risk. Therefore, doubts about a causal involvement of hyperhomocysteinemia (HHcy) and B-vitamin deficiencies in atherosclerosis persist. Existing evidence indicates that HHcy increases oxidative stress, causes endoplasmatic reticulum (ER) stress, alters DNA methylation and, thus, modulates the expression of numerous pathogenic and protective genes. Moreover, Hcy can bind directly to proteins, which can change protein function and impact the intracellular redox state. As most mechanistic evidence is derived from experimental studies with rather artificial settings, the relevance of these results in humans remains a matter of debate. Recently, it has also been proposed that HHcy and B-vitamin deficiencies may promote CVD through accelerated telomere shortening and telomere dysfunction. This review provides a critical overview of the existing literature regarding the role of HHcy and B-vitamin deficiencies in CVD. At present, the CVD risk associated with HHcy and B vitamins is not effectively actionable. Therefore, routine screening for HHcy in CVD patients is of limited value. However, B-vitamin depletion is rather common among the elderly, and in such cases existing deficiencies should be corrected. While Hcy-lowering with high doses of B vitamins has no beneficial effects in secondary CVD prevention, the role of Hcy in primary disease prevention is insufficiently studied. Therefore, more intervention and experimental studies are needed to address existing gaps in knowledge.
... Although the association between diet and telomere maintenance is currently under investigation, recent human studies indicate that specific dietary components may be considered a potential nutritional tool for preserving TL throughout the lifespan [11,12]. Given that the TL is affected by an inflammatory/oxidative status, it follows that a higher intake of antioxidant-rich foods and/or greater adherence to an anti-inflammatory diet may play a role in telomere maintenance and influence the overall health and longevity [13,14]. Indeed, current epidemiological and clinical data showed that higher consumption of vegetables, fruits, nuts, legumes, and seaweed is associated with longer TL [15][16][17]. ...
Telomeres are protective caps at the end of eukaryotic chromosomes, whose length is correlated with health and lifespan. Telomere attrition is a common feature of the aging process and can be accelerated by oxidative stress and chronic inflammation. Various nutrients influence the telomere length, partially due to their antioxidant and anti-inflammatory properties. The aim of this review was to meta-analytically assess the effect of omega-3 fatty acids on the telomere length. We searched four databases (PubMed, Web of Sciences, Scopus, and the Cochrane Library) from inception until November 2021. Of 573 records, a total of 5 clinical trials were included for the quantitative meta-analysis, comprising a total of 337 participants. The results revealed an overall beneficial effect of omega-3 fatty acids on the telomere length (mean difference = 0.16; 95% CI, 0.02, 0.30; p = 0.02). Despite a limited number of studies, the available evidence suggests that omega-3 fatty acids may positively affect the telomere length. However, larger clinical trials are needed to confirm our findings, along with studies aimed to clarify the underlying molecular mechanisms.
... 36,37 In addition, some studies have shown that shortened or dysfunctional telomeres are associated with hyperactivity of the transcription factor NF-kB and overexpression of inflammatory cytokines such as TNF-alpha and IL-6 in circulating macrophages. 38,39 Shortened TL has also been linked to the upregulation of NLRP3 inflammasome and the ATM-YAP1-pro-IL-18 pathway in inflammatory bowel diseases. 4,40 These findings imply that TL may be involved in the pathogenesis of immunemediated inflammatory diseases. ...
Background
Telomere maintenance is increasingly being considered as fundamental to the progression of immune-mediated inflammatory diseases. However, the causality underlying the purported relationship has not been fully elucidated. In the present work, we applied Mendelian randomization (MR) analysis to obtain estimates of the causal effect of telomere length (TL) on the risk of juvenile idiopathic arthritis (JIA) and JIA-associated iridocyclitis.
Methods
Two-sample MR analysis was conducted using summary-level data from the largest genome-wide association studies concerning TL (78,592 individuals), JIA (6056 cases and 25,086 controls), and JIA-associated iridocyclitis (1430 cases and 9,2767 controls). All the participants were of European ancestry. The inverse variance weighted (IVW) method was applied to estimate the causal effects. Sensitivity analyses incorporating multiple complementary MR approaches were implemented to test the robustness of the association and examine potential bias from pleiotropy.
Results
In our MR analysis, genetically predicted shorter TL was associated with an increased risk of JIA (IVW: odds ratio=1.68, 95% CI: 1.13–2.48, P=0.009), but not with the risk of JIA-associated iridocyclitis (IVW: odds ratio=1.75, 95% CI: 0.81–3.79, P=0.155). The other MR methods produced consistent results. Besides, a leave-one-out sensitivity analysis yielded similar findings and validated the robustness of the causal relationship. MR-Egger regression revealed no notable horizontal pleiotropy (intercept=0.046, P=0.175).
Conclusion
This work provides evidence of a negative association between TL and JIA risk, but not for the association between TL and the risk of JIA-associated iridocyclitis, in a European population. Future studies with larger sample sizes are warranted to elucidate the underlying role of TL in these diseases.
... Progressive telomere shortening is associated with loss of cellular proliferative capacity and premature reproductive aging, leading to chronic anovulation and infertility [11]. Several factors such as oxidative stress, inflammation, mitochondrial dysfunction, and hormonal alterations, as observed in PCOS, may accelerate telomere erosion [12]. On the other hand, increased levels of androgens in PCOS may be a protective factor improving telomerase activity [13] thereby not changing [7,14] or increasing telomere repeats [15]. ...
Metabolic and hormonal outcomes of polycystic ovary syndrome (PCOS) have implications on telomere biology and physical activity may prevent telomere erosion. We sought to observe the effects of continuous (CAT) and intermittent (IAT) aerobic training on telomere length, inflammatory biomarkers, and its correlation with metabolic, hormonal, and anthropometric parameters of PCOS. This randomized controlled clinical trial study included 87 PCOS randomly stratified according to body mass index (BMI) in CAT (n = 28), IAT (n = 29) and non-training control group (CG, n = 30). The exercises were carried out on a treadmill, three times per week for 16 weeks. The participants’ anthropometric characteristics and biochemical and hormonal concentrations were measured before and after aerobic training or observation period, as the telomere length that was evaluated using quantitative real-time PCR. Four months of aerobic exercises (CAT or IAT) did not alter telomere length and inflammatory biomarkers in PCOS women. Obesity index as BMI and waist circumference (WC), and inflammatory biomarkers negatively affect telomeres. The hyper-andro-genism measured by testosterone levels was reduced after both exercises (CAT, p ≤ 0.001; IAT, p = 0.019). In particular, the CAT reduced WC (p = 0.045), hip circumference (p = 0.032), serum cholesterol (p ≤ 0.001), and low-density lipoprotein (p = 0.030). Whereas, the IAT decreased WC (p = 0.014), waist-to-hip ratio (p = 0.012), free androgen index (FAI) (p = 0.037). WC (p = 0.049) and body fat (p = 0.015) increased in the non-training group while total cholesterol was reduced (p = 0.010). Booth exercises reduced obesity indices and hyperandrogenism on PCOS women without changes in telomere length or inflammatory biomarkers.
... Progressive telomere shortening is associated with loss of the cellular proliferative capacity and premature reproductive aging, leading to chronic anovulation and infertility [8]. Several factors as oxidative stress, in ammation, mitochondrial disfunction, and hormonal alterations, as observed in PCOS, may accelerate telomere erosion [9]. On the other hand, increased levels of androgens in PCOS may be a protective factor improving telomerase activity [10] thereby not changing [5,11] or increasing telomere repeats [12]. ...
Background: Physical activity is an effective non-pharmacological treatment for polycystic ovary syndrome (PCOS) and the reproductive outcomes which may have implications on telomere biology. Objective: To observe the effects of continuous (CAT) and intermittent (IAT) aerobic training on telomere length, inflammatory biomarkers, and its correlation with metabolic, hormonal, and anthropometric parameters of PCOS.
Design and Methods: This randomized controlled clinical trial study included 87 PCOS women randomly stratified according to body mass index (BMI) in the continuous (CAT, n = 28) and intermittent aerobic training (IAT, n = 29) and non-training control group (CG, n = 30). The exercises were carried out on a treadmill, three times per week for 16 weeks. The participants’ anthropometric characteristics and biochemical and hormonal concentrations were measured before and after aerobic training or observation period, as the telomere length that was evaluated using quantitative real-time PCR.
Results: Four months of aerobic exercises (CAT or IAT) did not alter telomere length and inflammatory biomarkers in PCOS women. Obesity index as BMI and waist circumference (WC), and inflammatory biomarkers negatively affect telomeres. The hyperandrogenism measured by testosterone levels was reduced after both exercises (CAT, p≤0.001; IAT, p=0.019). In particular, the CAT reduced WC (p=0.045), hip circumference (p= .032), serum cholesterol (p≤0.001), low-density lipoprotein (p=0.030). Whereas, the IAT decreased WC (p=0.014), waist-to-hip ratio (p=0.012), free androgen index (FAI) (p=0.037). WC (p=0.049) and body fat (p=0.015) increased in the non-training group while total cholesterol was reduced (p=0.010).
Conclusions: Booth exercises reduced obesity indices and hyperandrogenism on PCOS women without changes in telomere length or inflammatory biomarkers.
Clinical trial registration: Brazilian Clinical Trials Registry (ReBec; RBR-78qtwy, August 20, 2015), and the International Controlled Randomized Trial Registry (ISRCTN10416750, July 24, 2018), retrospectively registered.
Aging leads to a gradual decline in kidney function, making the kidneys increasingly vulnerable to various diseases. Oxidative stress, together with cellular senescence, has been established as paramount in promoting the aging process of the kidney. Oxidative stress, defined as an imbalance between ROS formation and antioxidant defense mechanisms, has been implicated in the kidney's cellular injury, inflammation, and premature senescence. Concurrently, the accumulation of SCs in the kidney also exacerbates oxidative stress via the secretion of pro-inflammatory and tissue-damaging factors as the senescence-associated secretory phenotype (SASP). Recently, SIRT1, a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase, has been pivotal in combating oxidative stress and cellular senescence in the aging kidney. SIRT1 acts as a potential antioxidant molecule through myriad pathways that influence diverse transcription factors and enzymes essential in maintaining redox homeostasis. SIRT1 promotes longevity and renal health by modulating the acetylation of cell cycle and senescence pathways. This review covers the complex relationship between oxidative stress and cellular senescence in the aging kidney, emphasizing the protective role of SIRT1.
See also the graphical abstract(Fig. 1).
Aging encompasses a wide array of detrimental effects that compromise physiological functions, elevate the risk of chronic diseases, and impair cognitive abilities. However, the precise underlying mechanisms, particularly the involvement of specific molecular regulatory proteins in the aging process, remain insufficiently understood. Emerging evidence indicates that c-Jun N-terminal kinase (JNK) serves as a potential regulator within the intricate molecular clock governing aging-related processes. JNK demonstrates the ability to diminish telomerase reverse transcriptase activity, elevate β-galactosidase activity, and induce telomere shortening, thereby contributing to immune system aging. Moreover, the circadian rhythm protein is implicated in JNK-mediated aging. Through this comprehensive review, we meticulously elucidate the intricate regulatory mechanisms orchestrated by JNK signaling in aging processes, offering unprecedented molecular insights with significant implications and highlighting potential therapeutic targets. We also explore the translational impact of targeting JNK signaling for interventions aimed at extending healthspan and promoting longevity.
Occupational pulmonary diseases (OPDs) pose a significant global health challenge, contributing to high mortality rates. This review delves into the pathophysiology of hypoxia and the safety of intermittent hypoxic conditioning (IHC) in OPD patients. By examining sources such as PubMed, Relemed, NLM, Scopus, and Google Scholar, the review evaluates the efficacy of IHC in clinical outcomes for OPD patients. It highlights the complexities of cardiovascular and respiratory regulation dysfunctions in OPDs, focusing on respiratory control abnormalities and the impact of intermittent hypoxic exposures. Key areas include the physiological effects of hypoxia, the role of hypoxia-inducible factor-1 alpha (HIF-1α) in occupational lung diseases, and the links between brain ischemia, stroke, and OPDs. The review also explores the interaction between intermittent hypoxic exposures, mitochondrial energetics, and lung physiology. The potential of IHE to improve clinical manifestations and underlying pathophysiology in OPD patients is thoroughly examined. This comprehensive analysis aims to benefit molecular pathologists, pulmonologists, clinicians, and physicians by enhancing understanding of IHE's clinical benefits, from research to patient care, and improving clinical outcomes for OPD patients.
Aging can lead to a series of degenerative changes in skeletal muscle, which would negatively impact physical activity and the quality of life of the elderly. Wolfberry contains numerous bioactive substances. It's vital to further explore the mechanisms underlying its healthy effects on skeletal muscle function during aging progress. This study discusses the benefits and mechanisms of aqueous extract of wolfberry (AEW) to protect skeletal muscle from aging‐related persistent DNA damage based on its anti‐inflammatory activity. It is found that AEW improves muscle mass, strength, and endurance, modulates the expression of Atrogin‐1, MyH, and MuRF‐1, and decreases oxidative stress and inflammation levels in aging mice, which is consistent with the in vitro results. Mechanistically, AEW inhibits the pattern recognition receptors (PRRs) pathway induced by inflammatory gene activation, suggesting its potential in response to DNA damage. AEW is also observed to mitigate chromatin decompaction. Network pharmacology is conducted to analyze the potential targets of AEW in promoting DNA repair. In conclusion, the study shows the anti‐aging effects of AEW on skeletal muscle by promoting DNA repair and reducing the transcriptional activity of inflammatory factors. AEW intake may become a potential strategy for strengthening skeletal muscle function in the elderly.
Existing research indicates that different types of meat have varying effects on health and aging, but the specific causal relationships remain unclear. This study aimed to explore the causal relationship between different types of meat intake and aging-related phenotypes. This study employed Mendelian randomization (MR) to select genetic variants associated with meat intake from large genomic databases, ensuring the independence and pleiotropy-free nature of these instrumental variables (IVs), and calculated the F-statistic to evaluate the strength of the IVs. The validity of causal estimates was assessed through sensitivity analyses and various MR methods (MR-Egger, weighted median, inverse-variance weighted (IVW), simple mode, and weighted mode), with the MR-Egger regression intercept used to test for pleiotropy bias and Cochran’s Q test employed to evaluate the heterogeneity of the results. The findings reveal a positive causal relationship between meat consumers and DNA methylation PhenoAge acceleration, suggesting that increased meat intake may accelerate the biological aging process. Specifically, lamb intake is found to have a positive causal effect on mitochondrial DNA copy number, while processed meat consumption shows a negative causal effect on telomere length. No significant causal relationships were observed for other types of meat intake. This study highlights the significant impact that processing and cooking methods have on meat’s role in health and aging, enhancing our understanding of how specific types of meat and their preparation affect the aging process, providing a theoretical basis for dietary strategies aimed at delaying aging and enhancing quality of life.
Accounting for 48% of malignant brain tumors in adults, glioblastoma has been of great interest in the last decades, especially in the biomolecular and neurosurgical fields, due to its incurable nature and notable neurological morbidity. The major advancements in neurosurgical technologies have positively influenced the extent of safe tumoral resection, while the latest progress in the biomolecular field of GBM has uncovered new potential therapeutical targets. Although GBM currently has no curative therapy, recent progress has been made in the management of this disease, both from surgical and molecular perspectives. The main current therapeutic approach is multimodal and consists of neurosurgical intervention, radiotherapy, and chemotherapy, mostly with temozolomide. Although most patients will develop treatment resistance and tumor recurrence after surgical removal, biomolecular advancements regarding GBM have contributed to a better understanding of this pathology and its therapeutic management. Over the past few decades, specific biomarkers have been discovered that have helped predict prognosis and treatment responses and contributed to improvements in survival rates.
Objectives
The association between dietary carotenoid intake and Soluble Klotho (S-Klotho) levels among the elderly population requires further evaluation. The purpose of this study is to evaluate the relationship between the dietary carotenoid intake and the S-Klotho plasma levels in older adults.
Methods
Eligible participants aged 60 years or above were selected from the National Health and Nutrition Examination Surveys (NHANES) data, collected between 2007 and 2016. The consumption of carotenoids was determined through two 24-hour dietary recall assessments. Moreover, the S-Klotho levels in the serum were measured using an Enzyme-Linked Immuno-Sorbent Assay (ELISA).
Results
A total of 5,056 participants were included in the study having a median total carotenoid intake of 9775.25 μg (95% confidence interval (CI): 8971.30−10579.21) and a median S-Klotho concentration of 815.59 pg/mL (95% CI: 802.59−828.60). The multivariable regression analysis showed that a single standard deviation increase in total carotenoid intake was significantly associated with an 8.40 pg/mL increase in S-Klotho levels (95% CI: 0.48−16.31). When the carotenoids were divided into quartiles, participants in the third ((4963.5μg/day,11662.5μg/day]) and fourth quartiles ((11662.5μg/day,377178μg/day]) showed higher S-Klotho levels compared to those in the first quartile. Among carotenoid subtypes, increased intake of α-carotene, β-carotene, and lutein with zeaxanthin was associated with elevated S-Klotho levels. These observed associations between carotenoid subtypes and S-Klotho levels remained consistent across male participants, having a normal weight, and a moderate physical activity based on stratified analysis.
Conclusion
The total carotenoid intake was positively related to plasma levels of S-Klotho in the elderly population, particularly for α-carotene, β-carotene, and lutein with zeaxanthin. However, further research is needed to confirm these findings and explore the underlying mechanisms behind this relationship.
Cellular senescence is a state of exiting the cell cycle, resisting apoptosis, and changing phenotype. Senescent cells (SCs) can be identified by large, distorted morphology and irreversible inability to replicate. In early development, senescence has beneficial roles like tissue patterning and wound healing, where SCs are cleared by the immune system. However, there is a steep rise in SC number as organisms age. The issue with SC accumulation stems from the loss of cellular function, alterations of the microenvironment, and secretions of pro‐inflammatory molecules, consisting of cytokines, chemokines, matrix metalloproteinases (MMPs), interleukins, and extracellular matrix (ECM)‐associated molecules. This secreted cocktail is referred to as the senescence‐associated secretory phenotype (SASP), a hallmark of cellular senescence. The SASP promotes inflammation and displays a bystander effect where paracrine signaling turns proliferating cells into senescent states. To alleviate age‐associated diseases, researchers have developed novel methods and techniques to selectively eliminate SCs in aged individuals. Although studies demonstrated that selectively killing SCs improves age‐related disorders, there are drawbacks to SC removal. Considering favorable aspects of senescence in the body, this paper reviews recent advancements in elimination strategies and potential rejuvenation targets of senescence to bring researchers in the field up to date.
Carotenoids are pigments that produce bright yellow, red, orange, and purple colors in some vegetables and fruits. These compounds play major roles in various critical functions of plants. Carotenoids are also indispensable for humans, exerting antioxidant effects and sustaining both low-light and color vision. The more than 700 different types of carotenoids can be divided into two classes: the carotenes (e.g., β-carotene and lycopene) which do not contain oxygen, and the xanthophylls (e.g., lutein and zeaxanthin) which contain oxygen. In addition, some carotenoids such as β-carotene and α-carotene can be converted by the human body into vitamins A; lutein, zeaxanthin, and lycopene are non-provitamin A carotenoids. The Republic of Suriname (South America) is renowned for its relatively high plant diversity which comprises about 5100 species of higher plants. Several of these plants have a relatively high content of carotenoids and are widely consumed and used as traditional medicines. In this chapter, the traditional uses of eight Surinamese fruits and vegetables rich in carotenoids have been addressed, and the pharmacological support for their traditional uses has comprehensively been dealt with. The chapter concludes with the scientific evidence to justify the traditional uses of the carotenoids in these plants.
Ethnopharmacological relevance:
Anoectochilusroxburghii (Wall.) Lindl. (AR), as an exceptionally valuable traditional Chinese medicine, has been widely used to treat hepatitis, cancer, diabetes, etc. But, the effects and the primary functioning element of AR on attenuating aging and aging-related learning and memory degradation has not yet been explored.
Aim of the study:
This study aimed at exploring the protective property of aqueous extract of AR (AEAR) on alleviation of aging and aging-related learning and memory impairment in vivo, and further investigating the main active ingredient and mechanism of AEAR.
Materials and methods:
D-galactose(D-gal) induced aging mice and HT22 cells exposed with L-Glutamic acid (Glu) were used as in vivo and in vitro model, separately. The effects of AEAR on aging and aging-related learning and memory degradation were explored by using morris water maze test, immunohistochemistry staining, biochemistry assay, etc. The effects and mechanism of AEAR and Kinsenoside (Kin) on antioxidation in vitro were investigated by cell viability assay, biochemistry assay, qRT-PCR, western blotting and molecular docking studies.
Results:
Treatment with AEAR (containing 69.52 ± 0.85% Kin, i.g.) for 63 days, alleviated low growth rate, abnormal brain, liver and thymus index, and decline in learning and memory capability of aging mice. Meanwhile, AEAR inhibited the decreased activities of SOD and GSH-PX, the decline in the ratio of GSH to GSSG, and the increase of MDA in both serum and brain, and also promoted the Nrf2 nuclear translocation in brain of aging mice induced by D-gal. The effects of AEAR on alleviating abnormal physiological characteristics, attenuating learning and memory impairment, and inhibiting oxidative stress in aging mice was similar to or even better than that of Vc. In HT22 cells exposed with Glu, Kin increased the cell viability, up-regulated the activities of SOD and GSH-PX, enhanced the ratio of GSH to GSSG, and down-regulated MDA, which was superior to AEAR. Kin up-regulated the ratio of p-ERK1/2 to ERK1/2, promoted the Nrf2 nuclear translocation and its downstream target genes, i.e. HO-1, NQO-1, GCLC and GCLM expression at the mRNA and protein levels, which were consistent with AEAR. Further, molecular docking results also confirmed that Kin had strong binding energy with ERK1 and ERK2.
Conclusion:
The present study indicated that Kin could alleviate the oxidative stress in aging mice via activating the ERK/Nrf2 signaling pathway, in order to attenuate aging and aging-related learning and memory impairment, as the main active ingredient of AR.
The ageing process begins at birth. It is a life-long process, and its exact origins are still unknown. Several hypotheses attempt to describe the normal ageing process, including hormonal imbalance, formation of reactive oxygen species, DNA methylation & DNA damage accumulation, loss of proteostasis, epigenetic alterations, mitochondrial dysfunction, senescence, inflammation, and stem cell depletion. With increased lifespan in elderly individuals, the prevalence of age-related diseases including, cancer, diabetes, obesity, hypertension, Alzheimer's, Alzheimer's disease and related dementias, Parkinson's, and other mental illnesses are increased. These increased age-related illnesses, put tremendous pressure & burden on caregivers, family members, and friends who are living with patients with age-related diseases. As medical needs evolve, the caregiver is expected to experience an increase in duties and challenges, which may result in stress on themselves, and impact their own family life. In the current article, we assess the biological mechanisms of ageing and its effect on body systems, exploring lifestyle and ageing, with a specific focus on age-related disorders. We also discussed the history of caregiving and specific challenges faced by caregivers in the presence of multiple comorbidities. We also assessed innovative approaches to funding caregiving, and efforts to improve the medical system to better organize chronic care efforts, while improving the skill and efficiency of both informal and formal caregivers. We also discussed the role of caregiving in end-of-life care. Our critical analysis strongly suggests that there is an urgent need for caregiving in aged populations and support from local, state, and federal agencies.
Aging has had and will have a considerable relevance in the population for millions of years. Various ways have been explored to prevent or prolong it, since aging is often accompanied by chronic degenerative diseases. Although not much information has been discovered about this, the participation of telomeres in aging has been studied. Telomeres are the ends of DNA that protect and prevent its degradation, however, the relationship of the presence of long telomeres to a long life has been contemplated in conjunction with the reduction of chronic degenerative diseases, so that these individuals have a more desirable quality of life than individuals who have shortened telomeres
Background: Telomere shortening causes intracellular signals that trigger programmed cell death. This study aimed to investigate the effect of resistance training with vitamin C consumption on Telomere Repeat-binding Factor 1 (TRF1) and Cyclin-Dependent Kinase 1 (CDK1) expression in skeletal muscle of elderly male Wistar rats. Methods: The present study was an experimental study with a control group. Twenty-five male rats (Wistar) aged 24 weeks (280-320 g) were randomly divided into 5 group; young control group, elderly group + resistance training, elderly group + liposomal vitamin C, elderly group + resistance training + liposomal vitamin C and old age control group. The duration of taking vitamins and doing exercise was eight weeks. Data analysis was performed at a significance level of α <0.05. Results: Aging significantly reduced CDK1 and TRF1 expression in skeletal muscle of rats (P = 0.001). Resistance training with vitamin C had a significant effect on CDK1 expression (P = 0.001). There was no significant change in TRF1 expression due to resistance training and vitamin C intake. Conclusion: Eight weeks of resistance training with vitamin C supplementation consumption in elderly rats significantly increases CDK1 in skeletal muscle but it did not have a significant effect on TRF1. Therefore, it is recommended to use a higher dose of vitamin C.
Aging is a progressive degenerative state accompanied by an increasing loss of physiological integrity and function. Mitochondria are relevant players in this process. According to “The mitochondrial free radical theory of aging” (MFRTA), proposed by Harman in the 1970s, the accumulation of reactive oxygen species (ROS) produced by mitochondria during life generates oxidative damage to proteins, lipids, and DNA. This in turn, contributes to the mitochondrial functionality decline and the aging process. Thanks to their properties, antioxidant molecules should contain the mitochondrial ROS production and extend lifespan. However, the controversial outcomes derived from research on antioxidants challenged MFRTA. In addition, ROS can have both beneficial and detrimental effects on longevity. This chapter describes the mitochondrial involvement in the aging process and the functions of antioxidants in the prevention of age-linked mitochondrial dysfunctions, particularly of vitamin E. Finally, the recent role of ROS as signaling molecules challenging MFRTA will be discussed.
Telomeres represent the ends of chromosomes, and they are composed of an extensive number of – TTAGGG nucleotide sequence repeats in humans. Telomeres prevent chromosome degradation, participate in stabilization, and regulate the DNA repair system. Inflammation and oxidative stress have been identified as important processes causing cardiovascular disease and accelerating telomere shortening rate. This review investigates the link between telomere length and pathological vascular conditions from experimental and human studies. Also, we discuss pharmacological treatments affecting telomeres and telomerase activity.
Aging is a progressive biological phenomenon of an organism that occurs over time, leading to a decrease in the ability to work adequately or to respond to metabolic stress. Aging has traditionally been perceived as a natural and biological phase. However, in the 21st century, people are living in a world that is incredibly modern, highly industrialized with a diet dominated by processed foods, and full of environmental toxins. This incredibly modern world is making our immune system overreactive, leading to systemic chronic inflammation and accelerated aging. Inflammation is a protective mechanism required for survival. It has beneficial effects on the neutralization of harmful agents. But too much inflammation over a long period gives rise to detrimental effects on different tissues by creating collateral damage. Now scientists consider human aging as “inflammaging” marked by systemic chronic inflammation. It is a major risk factor for both mortality and morbidity in elderly people and people who share the same pathology of inflammation. The risk of developing chronic inflammation or “inflammaging” is primarily attributed to genetics, antecedents, and environmental triggers. Inflammation is associated with its opposing mechanism, collectively referred to as antiinflammatory. This mechanism puts a halt on inflammation after elimination of the threat. Thus the health outcome of inflammation largely depends on the balance between proinflammatory and antiinflammatory pathways which also applies to inflammaging. Therefore, reducing the inflammation and balancing the duo with antiinflammatory therapies could be the major target for antiaging strategies.
Background
: Rhododendron nivale Hook. f (R.n), one of the four Manna Stash used in Tibetan medicine to delay aging, possesses anti-aging pharmacological activity. However, which R.n ingredients contain anti-aging properties and the underlying mechanisms involved are unclear.
Hypothesis/Purpose
Based on interactions between gut microbiota and natural medicines and the important role of gut microbiota in anti-aging, the study investigated the hypothesis that R.n possesses anti-aging properties and the interaction of gut microbiota with R.n is responsible for its anti-aging effects.
Study Design
: The primary active ingredients of R.n and their target function and pathway enrichment were explored. An aging mouse model was used to clarify the underlying anti-aging mechanisms of R.n.
Methods
: Chromatography, spectroscopy, nuclear magnetic technology, and pharmacology were used to reveal the major active ingredients of ethanol extract residues of R.n (RNEA). The target function and pathway enrichment of these active ingredients were explored. Plasma metabolomics coupled with intestinal flora evaluation and bioinformatics analysis was used to clarify the underlying anti-aging mechanisms of RNEA.
Results
: Myricetin-3-β-D-xylopyranoside, hyperin, goospetin-8-methyl ether 3-β-D-galactoside, and diplomorphanin B were separated and identified from RNEA. The network pharmacology study revealed that the active ingredients’ target function and pathway enrichment focused mainly on the glutathione antioxidant system. In a D-galactose-induced mouse model of aging, RNEA was shown to possess suitable anti-aging pharmacological activity, as indicated by the amelioration of memory loss and weakened superoxide dismutase and glutathione peroxidase activities. Plasma metabolomics coupled with intestinal flora examination and bioinformatics analysis revealed that RNEA could regulate the expression of glutathione-related enzymes and ameliorate D-galactose-induced imbalances in methionine, glycine, and serine, and betaine and galactose metabolism. The results showed that RNEA reshaped the disordered intestinal flora and mitigated the D-galactose-mediated decline in glutathione oxidase expression, further confirming that the anti-aging effect of RNEA was closely related to regulation of the glutathione antioxidant system.
Conclusion
: RNEA, consisting of myricetin-3-β-D-xylopyranoside, hyperin, goospetin-8-methyl ether 3-β-D-galactoside, and diplomorphanin B, possesses anti-aging activity. The anti-aging effect of RNEA might be due to reshaping intestinal flora homeostasis, increasing the expression of glutathione peroxidase 4 in the intestines and liver, enhancing glutathione peroxidase activity, and reinforcing the glutathione antioxidant system.
Aging is referred to progressive dysfunction of body organs, including the brain. This study aims to explore the anti-aging effect of combing nicotinamide mononucleotide (NMN) and lycopene (Lyco) (NMN+Lyco) on aging rats and senescent PC12 cells. Both in vivo and in vitro aging models were established using D-galactose (D-gal). The combination showed a trend to superiority over monotherapy in preventing aging in vivo and in vitro. Morris water maze test showed that NMN+Lyco effectively improved the ability of spatial location learning and memory of aging model rats. NMN+Lyco mitigated the oxidative stress of rat brains, livers, and PC12 cells by elevating the levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), GSH, as well as total antioxidant capacity (T-AOC), and reducing malondialdehyde (MDA) content. CCK-8 assay, senescence-associated β-galactosidase staining, and flow cytometer confirmed the cellular senescence of PC12 cells after exposing D-gal, and indicated the anti-senescence effect of NMN+Lyco in vitro. Moreover, NMN+Lyco effectively down-regulated the expressions of p53, p21, and p16 (senescence-related genes), and activated Keap1-Nrf2 signaling in both in vivo and in vitro aging models. In total, NMN+Lyco protected rats and PC12 cells from cognitive impairment and cellular senescence induced by D-gal, of which effects might be linked to the reduction of oxidative stress and the activation of Keap1-Nrf2 signaling.
Purpose:
Telomere length is a biomarker for aging. It is known that oxidative stress can accelerate telomere shortening, whereas antioxidants can delay their shortening. Carotenoids as antioxidants are favorably associated with health- and aging-related diseases caused by oxidative stress, but their association with telomere length is less certain. We investigated the association between blood carotenoid levels and leukocyte telomere length in a representative sample of US adults.
Methods:
We analyzed 3660 participants aged 20 years and older in the 1999-2002 National Health and Nutrition Examination Survey. The levels of carotenoids-alpha-carotene, beta-carotene (trans + cis), beta-cryptoxanthin, combined lutein/zeaxanthin, and trans-lycopene-were measured using high-performance liquid chromatography. The leukocyte telomere length (T/S ratio) was assayed using the quantitative polymerase chain reaction method.
Results:
A doubling of blood alpha-carotene, beta-carotene (trans + cis), and beta-cryptoxanthin was associated with approximately 2 % longer telomeres. Compared with the lowest carotenoid quartile of alpha-carotene, beta-carotene (trans + cis), and beta-cryptoxanthin, telomere length for adults with the highest quartiles was significantly increased by 5-8 %.
Conclusion:
We found that increasing levels of blood carotenoid were significantly associated with longer leukocyte telomeres in US adults. High intake of carotenoid-rich food may play a role in protecting telomeres and regulating telomere length.
Leukocyte telomere length (LTL) is considered one of the most predictive markers of biological aging. The aim of this study was to identify novel pathways regulating LTL using a metabolomics approach. To this end, we tested associations between 280 blood metabolites and LTL in 3511 females from TwinsUK and replicated our results in the KORA cohort. We furthermore tested significant metabolites for associations with several aging-related phenotypes, gene expression markers and epigenetic markers to investigate potential underlying pathways. Five metabolites were associated with LTL: Two lysolipids, 1-stearoylglycerophosphoinositol (P=1.6×10-5) and 1-palmitoylglycerophosphoinositol (P=1.6×10-5), were found to be negatively associated with LTL and positively associated with phospholipase A2 expression levels suggesting an involvement of fatty acid metabolism and particularly membrane composition in biological aging. Moreover, two gamma-glutamyl amino acids, gamma-glutamyltyrosine (P=2.5×10-6) and gamma-glutamylphenylalanine (P=1.7×10-5), were negatively correlated with LTL. Both are products of the glutathione cycle and markers for increased oxidative stress. Metabolites were also correlated with functional measures of aging, i.e. higher blood pressure and HDL cholesterol levels and poorer lung, liver and kidney function. Our results suggest an involvement of altered fatty acid metabolism and increased oxidative stress in human biological aging, reflected by LTL and age-related phenotypes of vital organ systems.
Telomerase activity controls telomere length, and this plays an important role in stem cells, aging and tumors. Antioxidant was shown to protect telomerase activity in normal cells but inhibit that in cancer cells, but the underlying mechanism is elusive. Here we found that 7721 hepatoma cells held a higher redox homeostasis threshold than L02 normal liver cells which caused 7721 cells to have a higher demand for ROS; MnSOD over-expression in 7721 decreased endogenous reactive oxygen species (ROS) and inhibited telomerase activity; Akt phosphorylation inhibitor and NAC both inhibited 7721 telomerase activity. The over-elimination of ROS by NAC resulted in the inhibition of Akt pathway. Our results suggest that ROS is involved in the regulation of cancer telomerase activity through Akt pathway. The different intracellular redox homeostasis and antioxidant system in normal cells and tumor cells may be the cause of the opposite effect on telomerase activity in response to NAC treatment. Our results provide a theoretical base of using antioxidants selectively inhibit cancer telomerase activity. Findings of the present study may provide insights into novel approaches for cancer treatment.
Mutations of human telomerase RNA component (TERC) and telomerase reverse transcriptase (TERT) are associated with a subset of lung aging diseases, but the mechanisms by which TERC and TERT participate in lung diseases
remain unclear. In this report, we show that knock-out (KO) of the mouse gene Terc or Tert causes pulmonary alveolar stem cell replicative senescence, epithelial impairment, formation of alveolar sacs, and characteristic
inflammatory phenotype. Deficiency in TERC or TERT causes a remarkable elevation in various proinflammatory cytokines, including
IL-1, IL-6, CXCL15 (human IL-8 homolog), IL-10, TNF-α, and monocyte chemotactic protein 1 (chemokine ligand 2 (CCL2)); decrease
in TGF-β1 and TGFβRI receptor in the lungs; and spillover of IL-6 and CXCL15 into the bronchoalveolar lavage fluids. In addition
to increased gene expressions of α-smooth muscle actin and collagen 1α1, suggesting myofibroblast differentiation, TERC deficiency
also leads to marked cellular infiltrations of a mononuclear cell population positive for the leukocyte common antigen CD45,
low-affinity Fc receptor CD16/CD32, and pattern recognition receptor CD11b in the lungs. Our data demonstrate for the first
time that telomerase deficiency triggers alveolar stem cell replicative senescence-associated low-grade inflammation, thereby
driving pulmonary premature aging, alveolar sac formation, and fibrotic lesion.
The low reprogramming efficiency in cells from elderly patients is a challenge that must be overcome. Recently, it has been reported that senescence-associated microRNA (miR)-195 targets Sirtuin 1 (SIRT1) to advance cellular senescence. Thus, we hypothesized that a blockade of miR-195 expression could improve reprogramming efficiency in old skeletal myoblasts (SkMs). We found that miR-195 expression was significantly higher in old SkMs (24 months) isolated from C57BL/6 mice as compared to young SkMs (2 months, 2.3-fold). Expression of SIRT1 and telomerase reverse transcriptase (TERT) was downregulated in old SkMs, and transduction of old SkMs with lentiviral miR-195 inhibitor significantly restored their expression. Furthermore, quantitative in situ hybridization analysis demonstrated significant telomere elongation in old SkMs transduced with anti-miR-195 (1.7-fold increase). It is important to note that blocking miR-195 expression markedly increased the reprogramming efficiency of old SkMs as compared to scramble (2.2-fold increase). Transduction of anti-miR-195 did not alter karyotype or pluripotency marker expression. Induced pluripotent stem cells (iPSCs) from old SkMs transduced with anti-miR-195 successfully formed embryoid bodies that spontaneously differentiated into three germ layers, indicating that deletion of miR-195 does not affect pluripotency in transformed SkMs. In conclusion, this study provided novel evidence that the blockade of age-induced miR-195 is a promising approach for efficient iPSC generation from aging donor subjects, which has the potential for autologous transplantation of iPSCs in elderly patients.
Objective
Telomere length shortening is modulated not only by aging, but also by both genetic and environmental factors. The aim of this study was to investigate the interactions between antioxidant nutrient metabolism-related gene single nucleotide polymorphisms (the genetic factors) and nutrient intake (the environmental factors) in their effects on telomere length shortening.
Setting & participants
Data were collected on the relative telomere lengths (RTLs) of buccal cells and the habitual food intake of 70 healthy Japanese adults.
Measurements
All subjects were genotyped for two common single nucleotide polymorphisms: rs6564851 in the β-carotene-15,15’-mono-oxygenase 1 (BCMO1) gene and rs362090 in the intestine-specific homeobox (ISX) gene.
Results
Univariate analysis revealed that buccal RTL was not significantly modulated by either age or gender. Then, we subdivided the study population into four groups based on combinations of the rs6564851 and rs362090 genotypes. After this subdivision, we showed a positive effect of daily α- or β-carotene intake on buccal RTL in the ISX rs362090 G-allele carrier + BCMO1 rs6564851 GG-genotype group (p = 0.026). Additionally, daily intake of another antioxidative fat-soluble vitamin, α-tocopherol, was positively associated with buccal RTL in the ISX rs362090 AA-homozygote + BCMO1 rs6564851 T-allele carrier group (p = 0.037).
Conclusion
Our study clearly indicates that high dietary intake of the antioxidants α, β-carotene and α-tocopherol protects buccal cells from RTL shortening, depending on the genetic background of antioxidant vitamin-related genes.
To determine the most important drivers of successful ageing at extreme old age, we combined community-based prospective cohorts: Tokyo Oldest Old Survey on Total Health (TOOTH), Tokyo Centenarians Study (TCS) and Japanese Semi-Supercentenarians Study (JSS) comprising 1554 individuals including 684 centenarians and (semi-)supercentenarians, 167 pairs of centenarian offspring and spouses, and 536 community-living very old (85 to 99years). We combined z scores from multiple biomarkers to describe haematopoiesis, inflammation, lipid and glucose metabolism, liver function, renal function, and cellular senescence domains. In Cox proportional hazard models, inflammation predicted all-cause mortality with hazard ratios (95% CI) 1.89 (1.21 to 2.95) and 1.36 (1.05 to 1.78) in the very old and (semi-)supercentenarians, respectively. In linear forward stepwise models, inflammation predicted capability (10.8% variance explained) and cognition (8.6% variance explained) in (semi-)supercentenarians better than chronologic age or gender. The inflammation score was also lower in centenarian offspring compared to age-matched controls with δ (95% CI)=-0.795 (-1.436 to -0.154). Centenarians and their offspring were able to maintain long telomeres, but telomere length was not a predictor of successful ageing in centenarians and semi-supercentenarians. We conclude that inflammation is an important malleable driver of ageing up to extreme old age in humans.
Telomere attrition might be one of the mechanisms through which psychosocial stress leads to somatic disease. To date it is unknown if exposure to adverse life events in adulthood is associated with telomere shortening prospectively. In the current study we investigated whether life events are associated with shortening of telomere length (TL).
Participants were 1094 adults (mean age 53.1, range 33-79 years) from the PREVEND cohort. Data were collected at baseline (T1) and at two follow-up visits after 4 years (T2) and 6 years (T3). Life events were assessed with an adjusted version of the List of Threatening Events (LTE). TL was measured by monochrome multiplex quantitative PCR at T1, T2, and T3. A linear mixed model was used to assess the effect of recent life events on TL prospectively. Multivariable regression analyses were performed to assess whether the lifetime life events score or the score of life events experienced before the age of 12 predicted TL cross-sectionally. All final models were adjusted for age, sex, body mass index, presence of chronic diseases, frequency of sports, smoking status, and level of education.
Recent life events significantly predicted telomere attrition prospectively (B = -0.031, p = 0.007). We were not able to demonstrate a significant cross-sectional relationship between the lifetime LTE score and TL. Nor did we find exposure to adverse life events before the age of 12 to be associated with TL in adulthood.
Exposure to recent adverse life events in adulthood is associated with telomere attrition prospectively.
A growing number of studies confirm an important effect of diet, lifestyle and physical activity on health status, the ageing process and many metabolic disorders. This study focuses on the influence of a diet supplement, NucleVital®Q10 Complex, on parameters related to redox homeostasis and ageing. An experimental group of 66 healthy volunteer women aged 35-55 supplemented their diet for 12 weeks with the complex, which contained omega-3 acids (1350 mg/day), ubiquinone (300 mg/day), astaxanthin (15 mg/day), lycopene (45 mg/day), lutein palmitate (30 mg/day), zeaxanthine palmitate (6 mg/day), L-selenomethionine (330 mg/day), cholecalciferol (30 µg/day) and α-tocopherol (45 mg/day). We found that NucleVital®Q10 Complex supplementation significantly increased total antioxidant capacity of plasma and activity of erythrocyte superoxide dismutase, with slight effects on oxidative stress biomarkers in erythrocytes; MDA and 4-hydroxyalkene levels. Apart from the observed antioxidative effects, the tested supplement also showed anti-ageing activity. Analysis of expression of SIRT1 and 2 in PBMCs showed significant changes for both genes on a mRNA level. The level of telomerase was also increased by more than 25%, although the length of lymphocyte telomeres, determined by RT-PCR, remained unchanged. Our results demonstrate beneficial effects concerning the antioxidant potential of plasma as well as biomarkers related to ageing even after short term supplementation of diet with NucleVital®Q10 Complex.
Telomere shortening is observed in peripheral mononuclear cells from patients with major depressive disorder (MDD). Whether this finding and its biological causes impact the health of the brain in MDD is unknown. Brain cells have differing vulnerabilities to biological mechanisms known to play a role in accelerating telomere shortening. Here, two glia cell populations (oligodendrocytes and astrocytes) known to have different vulnerabilities to a key mediator of telomere shortening, oxidative stress, were studied. The two cell populations were separately collected by laser capture micro-dissection of two white matter regions shown previously to demonstrate pathology in MDD patients. Cells were collected from brain donors with MDD at the time of death and age-matched psychiatrically normal control donors (N = 12 donor pairs). Relative telomere lengths in white matter oligodendrocytes, but not astrocytes, from both brain regions were significantly shorter for MDD donors as compared to matched control donors. Gene expression levels of telomerase reverse transcriptase were significantly lower in white matter oligodendrocytes from MDD as compared to control donors. Likewise, the gene expression of oxidative defence enzymes superoxide dismutases (SOD1 and SOD2), catalase (CAT) and glutathione peroxidase (GPX1) were significantly lower in oligodendrocytes from MDD as compared to control donors. No such gene expression changes were observed in astrocytes from MDD donors. These findings suggest that attenuated oxidative stress defence and deficient telomerase contribute to telomere shortening in oligodendrocytes in MDD, and suggest an aetiological link between telomere shortening and white matter abnormalities previously described in MDD.
Colorectal cancer (CRC) is the third most common cancer worldwide and, despite improved treatments, is still an important cause of cancer-related deaths. CRC encompasses a complex of diseases arising from a multi-step process of genetic and epigenetic events. Besides heterogeneity in the molecular and biological features of CRC, chromosomal instability is a hallmark of cancer and cancer cells may also circumvent replicative senescence and acquire the ability to sustain unlimited proliferation. Telomere/telomerase interplay is an important mechanism involved in both genomic stability and cellular replicative potential, and its dysfunction plays a key role in the oncogenetic process. The erosion of telomeres, mainly because of cell proliferation, may be accelerated by specific alterations in the genes involved in CRC, such as APC and MSH2. Although there is general agreement that the shortening of telomeres plays a role in the early steps of CRC carcinogenesis by promoting chromosomal instability, the prognostic role of telomere length in CRC is still under debate. The activation of telomerase reverse transcriptase (TERT), the catalytic component of the telomerase complex, allows cancer cells to grow indefinitely by maintaining the length of the telomeres, thus favouring tumour formation/progression. Several studies indicate that TERT increases with disease progression, and most studies suggest that telomerase is a useful prognostic factor. Plasma TERT mRNA may also be a promising marker for the minimally invasive monitoring of disease progression and response to therapy.
To examine the association between plasma concentrations of antioxidative micronutrients and leukocyte telomere length (LTL) in elderly adults.
Cross-sectional cohort study.
Austrian Stroke Prevention Study, a population-based cohort study on brain aging.
Individuals with a mean age of 66 ± 7 (n = 786; 58% female).
Concentrations of vitamin C, lutein, zeaxanthin, β-cryptoxanthin, canthaxanthin, lycopene, α- and γ-tocopherol, α- and β-carotene, and retinol in plasma, advanced oxidation protein products as a measure of oxidative stress in serum, and LTL were measured. Vitamins and carotenoids were measured using high-performance liquid chromatography, advanced oxidation protein products using spectrophotometry, and telomere length using quantitative real-time polymerase chain reaction.
Multiple linear regression analyses with adjustment for age and sex demonstrated that higher lutein, zeaxanthin, and vitamin C concentrations were strongly associated with longer telomere length. The associations were independent of body mass index, maximum oxygen uptake, and vascular risk factors and were not mediated by advanced oxidation protein products content.
This study provides first evidence that higher lutein, zeaxanthin, and vitamin C concentrations in plasma are associated with longer LTL in normal elderly persons and suggest a protective role of these vitamins in telomere maintenance.
Aging phenotypes are dictated by myriad cellular changes including telomere shortening. In most tissues, telomere shortening
is accelerated during replication if unrepaired oxidative damage to telomere sequences is present. However, the effect of
reactive oxygen species exposure on skeletal muscle telomeres is unknown. We sought to determine if oxidative stress shortens
telomeres in isolated adult rodent skeletal muscle fibers. Flexor digitorum brevis muscles were dissected from male mice (C57BL/6,
long telomere and CAST/Ei, wild-derived, short telomere) and dissociated into single fibers. Fibers were cultured at an oxygen
tension of 2%–5% for 5 days in control, hydrogen peroxide (oxidant), or a combination of N-acetylcysteine (antioxidant) and oxidant containing media. Telomere length, telomerase enzyme activity, and protein content
of TRF1 and TRF2 were subsequently measured. In both strains, oxidative stress resulted in significant telomere shortening
in isolated skeletal muscle fibers, likely by different mechanisms. Telomerase activity was not altered by oxidative stress
treatment but was significantly different between strains, with greater telomerase activity in long-telomere–bearing C57BL/6
mice. These results provide important insights into mechanisms by which oxidative stress could shorten skeletal muscle telomeres.
We adduce proof that telomere shortening is the sole mechanism of aging. All apparent contradictions, particularly the absence of an inverse correlation between residual telomere length and donor age, are explained within the bounds of telomere theory. We explain in what way telomere shortening might be the cause of aging and lifespan restriction. We also show the inability of the oxidative theory to explain a number of indisputable (and easily explained by telomere theory) facts, such as malignant growth of tumor cells and why children begin aging not from the level reached by the cells of their parents at the moment of conception but from nothing. We postulate that if oxidative damage was entirely absent, telomeres would, nevertheless, shorten with each mitotic cycle because this is the mechanism of DNA replication. Aging would occur all the same, and it is the very thing we can observe under the effect of any antioxidants. If telomeres do not shorten, as is the case in transformed cells in which telomerase is working, aging will do stop and transformed cells will show no senescence. We also observe this in spite of the damaging effect of reactive oxygen species, which is even more intensive in transformed cells than in normal cells.
Telomeres are specialized structures providing chromosome integrity during cellular division along with protection against premature senescence and apoptosis. Accelerated telomere attrition in patients with Myelodysplastic Syndrome (MDS) occurs by an undefined mechanism. Although the MDS clone originates within the myeloid compartment, T-lymphocytes display repertoire contraction and loss of naïve T-cells. The replicative lifespan of T-cells is stringently regulated by telomerase activity. In MDS cases, we show that purified CD3+ T-cells have significantly shorter telomere length and reduced proliferative capacity upon stimulation compared to controls. To understand the mechanism, telomerase enzymatic activity and telomerase reverse transcriptase (hTERT) gene expression were compared in MDS cases (n=35) and healthy controls (n=42) within different T-cell compartments. Telomerase activity is greatest in naïve T-cells illustrating the importance of telomere repair in homeostatic repertoire regulation. Compared to healthy controls, MDS cases had lower telomerase induction (P<0.0001) that correlated with significantly lower hTERT mRNA (P<0.0001), independent of age and disease stratification. hTERT mRNA deficiency affected naïve but not memory T-cells, and telomere erosion in MDS occurred without evidence of an hTERT-promoter mutation, copy number variation or deletion. Telomerase insufficiency may undermine homeostatic control within the hematopoietic compartment and promote a change in the T-cell repertoire in MDS.Leukemia accepted article preview online, 17 October 2012; doi:10.1038/leu.2012.300.
Dietary energy restriction in mammals, particularly at a young age, extends the life span. Leukocyte telomere length (LTL) is thought to be a bioindicator of aging in humans. High n-6 (omega-6) PUFA intake may accelerate LTL attrition.
We determined whether lower energy and higher PUFA intakes in young adulthood are associated with shorter LTL in cross-sectional and longitudinal analyses.
In a longitudinal observational study (405 men, 204 women), diet was determined at baseline by a semiquantitative food-frequency questionnaire, and LTL was determined by Southern blots at mean ages of 30.1 y (baseline) and 43.2 y (follow-up). Spearman correlations and multivariable linear regression were used.
Baseline energy intake was inversely associated with follow-up LTL in men (standardized β = -0.171, P = 0.0005) but not in women (P = 0.039 for sex interaction). The difference in men between the highest and lowest quintiles of energy was 244 base pairs (bp) (95% CI: 59, 429 bp) and between extreme quintiles of LTL was 440 kcal (95% CI: 180, 700 kcal). Multivariable adjustment modestly attenuated the association (β = -0.157, P = 0.002). Inverse associations, which were noted for all macronutrients, were strongest for the unsaturated fatty acids. In multivariable models including energy and the macronutrients (as percentage of energy), the significant inverse energy-LTL association (but not the PUFA-LTL association) persisted. The energy-LTL association was restricted to never smokers (standardized β = -0.259, P = 0.0008; P = 0.050 for the smoking × calorie interaction).
The inverse calorie intake-LTL association is consistent with trial data showing beneficial effects of calorie restriction on aging biomarkers. Further exploration of energy intake and LTL dynamics in the young is needed.
There is now evidence that depression, as characterized by melancholic symptoms, anxiety, and fatigue and somatic (F&S) symptoms, is the clinical expression of peripheral cell-mediated activation, inflammation and induction of oxidative and nitrosative stress (IO&NS) pathways and of central microglial activation, decreased neurogenesis and increased apoptosis. This review gives an explanation for the multiple "co-morbidities" between depression and a large variety of a) brain disorders related to neurodegeneration, e.g. Alzheimer's, Parkinson's and Huntington's disease, multiple sclerosis and stroke; b) medical disorders, such as cardiovascular disorder, chronic fatigue syndrome, chronic obstructive pulmonary disease, rheumatoid arthritis, psoriasis, systemic lupus erythematosus, inflammatory bowel disease, irritable bowel syndrome, leaky gut, diabetes type 1 and 2, obesity and the metabolic syndrome, and HIV infection; and c) conditions, such as hemodialysis, interferon-α-based immunotherapy, the postnatal period and psychosocial stressors. The common denominator of all those disorders/conditions is the presence of microglial activation and/or activation of peripheral IO&NS pathways. There is evidence that shared peripheral and / or central IO&NS pathways underpin the pathophysiology of depression and the previously mentioned disorders and that activation of these IO&NS pathways contributes to shared risk. The IO&NS pathways function as a smoke sensor that detect threats in the peripheral and central parts of the body and signal these threats as melancholic, anxiety, and fatigue and somatic (F&S) symptoms. The presence of concomitant depression is strongly associated with a lower quality of life and increased morbidity and mortality in medical disorders. This may be explained since depression contributes to increased (neuro)inflammatory burden and may therefore drive the inflammatory and degenerative progression. It is concluded that the activation of peripheral and / or central IO&NS pathways may explain the co-occurrence of depression with the above disorders. This shows that depression belongs to the spectrum of inflammatory and degenerative disorders.
Epigallocatechin-3-gallate (EGCG), a major component of green tea polyphenols (GTP), has been reported to downregulate telomerase activity in breast cancer cells thereby increasing cellular apoptosis and inhibiting cellular proliferation. However, the major concerns with GTPs are their bioavailability and stability under physiologic conditions. In the present study, we show that treatments with EGCG and a novel prodrug of EGCG (pro-EGCG or pEGCG) dose- and time-dependently inhibited the proliferation of human breast cancer MCF-7 and MDA-MB-231 cells but not normal control MCF10A cells. Furthermore, both EGCG and pro-EGCG inhibited the transcription of hTERT (human telomerase reverse transcriptase), the catalytic subunit of telomerase, through epigenetic mechanisms in estrogen receptor (ER)-positive MCF-7 and ER-negative MDA-MB-231 cells. The downregulation of hTERT expression was found to be because of hTERT promoter hypomethylation and histone deacetylations, mediated at least partially through inhibition of DNA methyltransferase and histone acetyltransferase activities, respectively. In addition, we also observed that EGCG and pEGCG can remodel chromatin structures of the hTERT promoter by decreasing the level of acetyl-H3, acetyl-H3K9, and acetyl-H4 to the hTERT promoter. EGCG and pEGCG induced chromatin alterations that facilitated the binding of many hTERT repressors such as MAD1 and E2F-1 to the hTERT regulatory region. Depletion of E2F-1 and MAD1 by using siRNA reversed the pEGCG downregulated hTERT expression and associated cellular apoptosis differently in ER-positive and ER-negative breast cancer cells. Collectively, our data provide new insights into breast cancer prevention through epigenetic modulation of telomerase by using pro-EGCG, a more stable form of EGCG, as a novel chemopreventive compound.
Dyskeratosis congenita (DC) is a multi-system disorder which in its classical form is characterised by abnormalities of the skin, nails and mucous membranes. In approximately 80% of cases, it is associated with bone marrow dysfunction. A variety of other abnormalities (including bone, brain, cancer, dental, eye, gastrointestinal, immunological and lung) have also been reported. Although first described almost a century ago it is the last 10 years, following the identification of the first DC gene (DKC1) in 1998, in which there has been rapid progress in its understanding. Six genes have been identified, defects in which cause different genetic subtypes (X-linked recessive, autosomal dominant, autosomal recessive) of DC. The products of these genes encode components that are critical for telomere maintenance; either because they are core constituents of telomerase (dyskerin, TERC, TERT, NOP10 and NHP2) or are part of the shelterin complex that protects the telomeric end (TIN2). These advances have also highlighted the connection between the more "cryptic/atypical" forms of the disease including aplastic anaemia and idiopathic pulmonary fibrosis. Equally, studies on this disease have demonstrated the critical importance of telomeres in human cells (including stem cells) and the severe consequences of their dysfunction. In this context DC and related diseases can now be regarded as disorders of "telomere and stem cell dysfunction".
Telomeres are protein-DNA complexes localized at the ends of linear chromosomes constituted by short, tandem G-rich hexanucleotide repeats and associated proteins. Their length shortens with each cell division and correlates inversely with age. It can be modified by genetic and epigenetic factors, sex hormones, reactive oxygen species and inflammatory reactions. A critical minimum length of telomeres triggers a cell cycle arrest or senescence of the cell. The immune system is highly sensitive to shortening of telomeres as its competence depends strictly on cell renewal and clonal expansion of T- and B-cell populations. Cells of the immune system are unique among normal somatic cells as they can up-regulate telomerase, the telomere extending enzyme, and limit telomere attrition in the process of cell proliferation undergoing in activated cells. Telomere length is highly variable among humans. Lineage-specific telomere shortening with different kinetics of telomere attrition was observed in CD4+, CD8+ T lymphocytes, B lymphocytes, granulocytes, monocytes and NK cell population. Immunosenescence is characterized by a special remodeling of the immune system induced by antigen exposure and oxidative stress. In ageing immune system adaptive immunity deteriorates because of a progressive decline of naive T and B cells and decrease of absolute numbers of T and B lymphocytes. The innate compartment of the immune system is relatively well preserved although some age-dependent alterations can be also observed. Nonagenarians or centenarians represent phenomenon of successful ageing of the immune system as most of their immune parameters are well preserved.
Mild oxidative stress as exerted by culture of human WI-38 fibroblasts under 40% oxygen partial pressure blocks proliferation irreversibly after one to three population doublings. Hyperoxically blocked cells are similar to senescent ones in terms of general morphology and lipofuscin accumulation. Moreover, they, like senescent fibroblasts, are blocked preferentially in G1 as evident from DNA content measurements by flow cytometry. Southern blotting of AluI- and HinfI-restricted genomic DNA shows an increase of the rate of telomere shortening from 90 bp per population doubling under normoxia to more than 500 bp per population doubling under hyperoxia. In every case, proliferation is blocked if a telomere cutoff length of about 4 kb is arrived at. The fact that telomere length correlates with the final inhibition of proliferation under conditions of varied oxidative stress, while the population doubling level does not, suggests that telomere shortening provides the signal for cell cycle exit in senescence. In postmitotic cells, no further telomere shortening occurs. However, the sensitivity of terminal restriction fragments to S1 nuclease increases, indicating the accumulation of single-strand breaks in telomeres of nondividing fibroblasts. This effect is found both under normoxic and hyperoxic culture, although it is more pronounced under conditions of higher oxidative stress. It might be speculated that accumulation of single-strand breaks and the resultant loss of distal single-stranded fragments during replication could be a major cause of telomere shortening, possibly more important than incomplete replication per se.
Replicative senescence and oxidative stress have been implicated in ageing, endothelial dysfunction and atherosclerosis. Replicative senescence is determined primarily by telomere integrity. In endothelial cells the glutathione redox-cycle plays a predominant role in the detoxification of peroxides. The aim of this study was to elucidate the role of the glutathione-dependent antioxidant system on the replicative capacity and telomere dynamics of cultured endothelial cells. Human umbilical vein endothelial cells were serially passaged while exposed to regular treatment with 0.1 microM tert-butyl hydroperoxide, a substrate of glutathione peroxidase, or 10 microM L-buthionine-[S,R]-sulphoximine, an inhibitor of glutathione synthesis. Both treatments induced intracellular oxidative stress but had no cytotoxic or cytostatic effects. Nonetheless, treated cultures entered senescence prematurely (30 versus 46 population doublings), as determined by senescence-associated beta-galactosidase staining and a sharp decrease in cell density at confluence. In cultures subjected to oxidative stress terminal restriction fragment (TRF) analysis demonstrated faster telomere shortening (110 versus 55 bp/population doubling) and the appearance of distinct, long TRFs after more than 15-20 population doublings. Fluorescence in situ hybridisation analysis of metaphase spreads confirmed the presence of increased telomere length heterogeneity, and ruled out telomeric end-to-end fusions as the source of the long TRFs. The latter was also confirmed by Bal31 digestion of genomic DNA. Similarly, upregulation of telomerase could not account for the appearance of long TRFs, as oxidative stress induced a rapid and sustained decrease in this activity. These findings demonstrate a key role for glutathione-dependent redox homeostasis in the preservation of telomere function in endothelial cells and suggest that loss of telomere integrity is a major trigger for the onset of premature senescence under mild chronic oxidative stress.
Mammalian telomeres consist of long tandem arrays of double-stranded telomeric TTAGGG repeats packaged by the telomeric DNA-binding proteins TRF1 and TRF2. Both contain a similar C-terminal Myb domain that mediates sequence-specific binding to telomeric DNA. In a DNA complex of TRF1, only the single Myb-like domain consisting of three helices can bind specifically to double-stranded telomeric DNA. TRF2 also binds to double-stranded telomeric DNA. Although the DNA binding mode of TRF2 is likely identical to that of TRF1, TRF2 plays an important role in the t-loop formation that protects the ends of telomeres. Here, to clarify the details of the double-stranded telomeric DNA-binding modes of TRF1 and TRF2, we determined the solution structure of the DNA-binding domain of human TRF2 bound to telomeric DNA; it consists of three helices, and like TRF1, the third helix recognizes TAGGG sequence in the major groove of DNA with the N-terminal arm locating in the minor groove. However, small but significant differences are observed; in contrast to the minor groove recognition of TRF1, in which an arginine residue recognizes the TT sequence, a lysine residue of TRF2 interacts with the TT part. We examined the telomeric DNA-binding activities of both DNA-binding domains of TRF1 and TRF2 and found that TRF1 binds more strongly than TRF2. Based on the structural differences of both domains, we created several mutants of the DNA-binding domain of TRF2 with stronger binding activities compared to the wild-type TRF2.
Immune aging manifests with a combination of failing adaptive immunity and insufficiently restrained inflammation. In patients with rheumatoid arthritis (RA), T cell aging occurs prematurely, but the mechanisms involved and their contribution to tissue-destructive inflammation remain unclear. We found that RA CD4⁺ T cells showed signs of aging during their primary immune responses and differentiated into tissue-invasive, proinflammatory effector cells. RA T cells had low expression of the double-strand-break repair nuclease MRE11A, leading to telomeric damage, juxtacentromeric heterochromatin unraveling, and senescence marker upregulation. Inhibition of MRE11A activity in healthy T cells induced the aging phenotype, whereas MRE11A overexpression in RA T cells reversed it. In human-synovium chimeric mice, MRE11Alow T cells were tissue-invasive and pro-arthritogenic, and MRE11A reconstitution mitigated synovitis. Our findings link premature T cell aging and tissue-invasiveness to telomere deprotection and heterochromatin unpacking, identifying MRE11A as a therapeutic target to combat immune aging and suppress dysregulated tissue inflammation.
Background
Results regarding telomere length and cancer risk are conflicting. We tested the hypothesis that long telomeres are associated with increased risk of any cancer and specific cancer types in genetic and observational analyses.
Methods
Individuals (N = 95 568) from the Copenhagen City Heart Study and the Copenhagen General Population Study had the telomere length-associated genotypes rs7726159 (TERT), rs1317082 (TERC), and rs2487999 (OBFC1) determined, and 65 176 had telomere length measured. A total of 10 895 individuals had had a cancer diagnosis. Endpoints were any cancer and 25 specific cancer types. We conducted Cox regression analyses and logistic regression analyses. The three genotypes were combined as an allele sum.
Results
Telomere length increased 67 base-pairs [95% confidence interval (CI) 61–74] per allele. In logistic regression models, the per-allele odds ratio (OR) for cancer was 1.05 (95% CI 1.03–1.07) for the allele sum, 1.05 (1.02–1.09) for rs7726159, 1.05 (1.02–1.08) for rs1317082 and 1.07 (1.02–1.12) for rs2487999. In contrast, the hazard ratio for any cancer was 1.01 (1.00–1.01) per 200-base-pair increase in telomere length in multivariable adjusted observational analysis. In genetic analyses according to specific cancer types, the per-allele odds ratio was 1.19 (1.12–1.27) for melanoma and 1.14 (1.06–1.22) for lung cancer.
Conclusions
Genetic determinants of long telomeres are associated with increased cancer risk, particularly melanoma and lung cancer. This genetic predisposition to enhanced telomere maintenance may represent a survival advantage for pre-cancerous cells, allowing for multiple cell divisions leading to cancer development.
Exposure to psychosocial stress is associated with increased risk of a number of somatic and mental disorders with relation to immune system functioning. We aimed to explore whether stressful events in early and recent life was associated with leucocyte telomere length (TL), which is assumed to reflect the accumulated burden of inflammation and oxidative stress occurring during the life course. We specifically aimed to address whether childhood constitutes a sensitive period and how much of the relation between stressful life events and TL is mediated through somatic and mental health, lifestyle, and markers of low-grade inflammation. A cohort of Danish men born in 1953 has been followed since birth in the Metropolit Cohort. These men underwent a health examination including blood sampling in 2010 and a subset of 324 also had a quantitative PCR-based measurement of TL. The relation between stressful life events and TL was analysed using structural equation modelling, which also provided an estimate of the proportion of the total effect mediated by somatic and mental health (cardiovascular disease, body mass and depressive mood), lifestyle factors, and low grade inflammation (C-reactive protein (CRP), interleukin (IL)-6 and IL-10). Total number of stressful events experienced during the life course was not associated with TL. In terms of sensitive periods, we found that number of stressful events in childhood was associated with shorter TL (βper number stressful events in childhood =-0.02(SE=-0.02); P=0.05). This relation was particularly strong for being placed away from home (β=-0.16; P<.000). Thirty percent of the total effect of stressful events in childhood on TL was mediated by the included variables, with the largest proportion being mediated through depressive mood (16%) and CRP (9%). This study suggests that stressful events in childhood are associated with shorter TL in middle-aged men and that part of this relation is explained by depressive mood and low grade inflammation.
Background:
Manganese superoxide dismutase (MnSOD) is an important antioxidant enzyme affected in heart/muscle-specific MnSOD-deficient mice (H/M-SOD2(-/-)), which develop progressive congestive heart failure and exhibit pathology typical of dilated cardiomyopathy.
Methods:
In this study we investigated the beneficial effects of epigallocatechin gallate (EGCG) on the cardiac remodeling and telomere biology in H/M-SOD2(-/-) mice. H/M-SOD2(-/-) mice were divided into three groups: those receiving normal drinking water (KO), a low dose of EGCG (L: 10mg/L), and a high dose of EGCG (H: 100mg/L) beginning at eight weeks of age and lasting for eight weeks.
Results:
The mice in the KO group exhibited significantly dilated cardiac remodeling with reduced contractility, which was prevented by the administration of EGCG. Although the mortality of KO mice was about 50% at 16 weeks of age, the mice that received EGCG had a high survival rate. The cardiac dilatation with reduced cardiac contraction in KO mice was prevented by EGCG treatment. The levels of myocardial oxidative stress and free fatty acids were lower in the group treated with EGCG compared with the KO group. The increased expression of nitric oxide synthase 2, nitrotyrosine, fatty acid synthase, Toll-like receptor 4, and Sirt1 in the KO mice were prevented by EGCG treatment. The shortening of the telomere length, decreased telomerase activity in KO mice were also prevented by EGCG.
Conclusions:
H/M-SOD2(-/-) mice receiving EGCG have a lower mortality rate and exhibit less inflammation and a better preserved cardiac function and telomere biology.
Objective:
The prevalence of obesity increases with age and is higher in each younger generation (unfavorable generation shift). This may influence patterns of oxidative stress and inflammation. Age-related changes and generation shifts in markers of oxidative stress and inflammation were investigated, specifically addressing the role of body mass index (BMI).
Methods:
Four generations (aged 26-35, 36-45, 46-55, and 56-65 at baseline) (N = 5,155) were examined every 5 years for 15 years between 1993 and 2012. Random coefficient analyses were used to study age-related changes and generation shifts in BMI, γ-glutamyltransferase (GGT), uric acid (UA), and C-reactive protein (CRP).
Results:
Levels of BMI, UA, and CRP increased in all generations up to age 75, whereas GGT increased up to age 55. No consistent generation shifts were observed for GGT, UA, and CRP (P ≥ 0.05). Participants with a stable BMI (change ≤1 kg/m(2) /15 years) had either no or small increases with age in GGT, UA, and CRP, whereas participants with increasing BMI (increase >1 kg/m(2) /15 years) had much larger increases (P < 0.01).
Conclusions:
The unfavorable age-related changes in obesity-related biochemical markers, particularly among individuals with increasing BMI, show the importance of maintaining a healthy weight to improve population levels of oxidative stress and inflammation.
Background:
Obesity is reported to be associated with immune dysfunction and a state of low-grade, chronic inflammation. Either pomegranate extract (PomE) or exercise (Ex) has been shown to have antiobesity, anti-inflammatory and antioxidant effects. Nevertheless, no study has addressed the additive benefits of PomE and Ex on the restoration of obesity-induced immune defects.
Objective:
The present work aims to study the effect of PomE and Ex as a combined intervention on immune function and the underlying mechanism involved in inflammation and oxidative stress in rats with high-fat-diet (HFD)-induced obesity.
Results:
Our results demonstrate that the combination of PomE and Ex showed additive benefits on inhibition of HFD-induced body weight increase and improvement of HFD-induced immune dysfunction, including (a) attenuating the abnormality of histomorphology of the spleen, (b) increasing the ratio of the CD4+:CD8+ T cell subpopulations in splenocytes and peripheral blood mononuclear cells (PBMC), (c) inhibition of apoptosis in splenocytes and PBMC, (d) normalizing peritoneal macrophage phenotypes and (e) restoring immunomodulating factors in serum. We also find that immune dysfunction in HFD-fed rats was associated with increased inflammatory cytokine secretion and oxidative stress biomarkers, and that the combination of PomE and Ex effectively inhibited the inflammatory response and decreased oxidative damage.
Conclusions:
The effect of PomE and Ex as a combined intervention is greater than the effect of either PomE or Ex alone, showing that PomE and Ex may be additively effective in improving immune function in HFD-fed rats by inhibiting inflammation and decreasing oxidative stress.
Background:
Dietary factors can affect telomere length (TL), a biomarker of aging, through oxidation and inflammation-related mechanisms. A Dietary Inflammatory Index (DII) could help to understand the effect of the inflammatory potential of the diet on telomere shortening.
Objective:
This study aimed to determine the association of the DII with TL and to examine whether diet-associated inflammation could modify the telomere attrition rate after a 5-y follow-up of a Mediterranean dietary intervention.
Design:
This was a prospective study of 520 participants at high cardiovascular disease risk (mean ± SD age: 67.0 ± 6.0 y, 45% males) from the PREDIMED-NAVARRA (PREvención con DIeta MEDiterránea-NAVARRA) trial. Leukocyte TL was measured by quantitative real-time polymerase chain reaction at baseline and after 5 y of follow-up. The DII was calculated from self-reported data by using a validated 137-item food-frequency questionnaire.
Results:
Longer telomeres at baseline were found in participants who had a more anti-inflammatory diet (lowest DII score) (P-trend = 0.012). Longitudinal analyses further showed that a greater anti-inflammatory potential of the diet (i.e., a decrease in the DII) could significantly slow down the rate of telomere shortening. Moreover, the multivariable-adjusted OR for short telomeres (z score ≤20th percentile) was 1.80 (95% CI: 1.03, 3.17) in a comparison between the highest (proinflammatory) and the lowest (anti-inflammatory) DII tertiles. Similarly, a greater DII (greatest proinflammatory values) after a 5-y follow-up was associated with almost a 2-fold higher risk of accelerated telomere attrition compared with the highest decrease in DII (greatest anti-inflammatory values) during this period (P-trend = 0.025).
Conclusions:
This study showed both cross-sectional and longitudinal associations between the inflammatory potential of the diet and telomere shortening in subjects with a high cardiovascular disease risk. Our findings are consistent with, but do not show, a beneficial effect of adherence to an anti-inflammatory diet on aging and health by slowing down telomere shortening. These results suggest that diet might play a key role as a determinant of TL through proinflammatory or anti-inflammatory mechanisms. This trial was registered at controlled-trials.com as ISRCTN35739639.
Oxidative stress can alter the expression level of microRNAs (miRNAs) and has a role in oxidative damage generated by reactive oxygen species (ROS). While previous studies have demonstrated that miR‑146a, miR‑21 and miR‑150 are essential for ROS production in heart disease, the role of these miRNAs in spinal cord injuries has not yet been examined. The present study focused on examining the role of miR‑146a, miR‑21 and miR‑150 during H2O2 stimulation in rat neuronal spinal cord (RN‑sc) cells. RN‑sc cells were treated with H2O2, and cells were harvested for reverse transcription quantitative polymerase chain reaction (RT‑qPCR) to detect the expression levels of miR‑146a, miR‑21 and miR‑150. The results demonstrated that miR‑146a, miR‑21 and miR‑150 expression was upregulated during H2O2 treatment. T-cell death and apoptosis were investigated using an MTT assay and flow cytometric analysis, respectively. Following miR‑21 silencing, H2O2‑induced cell death and apoptosis were reduced in RN‑sc cells, while miR‑150 silencing had no effect. Furthermore, Smad7 was identified as a direct target of miR‑21 using a Luciferase reporter assay, RT-qPCR and western blot analysis. In addition, while H2O2 downregulated Smad7 protein expression, this was reversed by inhibiting miR‑21 expression. Based on previous studies, it was predicted that miR‑21 has a role in ROS production through regulating Smad7 in rat spinal cord neurons.
To investigate the roles and mechanism(s) of epigallocatechin gallate (EGCG) in carcinogenesis in malignant transformed cell line, cadmium-induced malignant transformed cells were treated with different doses of EGCG. Then cell proliferation, cell apoptosis, hTERT mRNA and protein level, and c-Myc protein levels were measured at different time points. EGCG was found to inhibit cell proliferation in a dose-dependent manner. Cell cycle was changed in the transformed cells after EGCG treatment with significantly increased cell numbers in G0/G1 phase and decreased cell numbers in S phase compared to control group, P < 0.001. EGCG was also found to promote cell apoptosis with a time-dependent manner. Both mRNA and protein levels of hTERT gene were significantly decreased in cells after treated with EGCG, P < 0.001. c-Myc protein level was significantly decreased after EGCG treatment, especially in the highest dose group (i.e. 200 μg/ml). The decrease in c-Myc protein level was accompanied by the reduction of hTERT protein levels. EGCG can inhibit cell proliferation and promote apoptosis in malignant cadmium-transformed cell line. The mechanism may be its ability to reduce c-Myc gene expression and consequently inhibits hTERT gene expression, which in turn decrease the telomerase activity.
Myalgic encephalomyelitis (ME), chronic fatigue syndrome (CFS) and chronic fatigue (CF) are distinct diagnostic categories with regard to clinical symptoms, severity of illness and biomarkers. Patients with ME and CFS show higher scores on fatigue, neurocognitive disorders, hyperalgesia, autonomic symptoms, postexertional malaise and a subjective feeling of infection than patients with CF. ME is characterized by increased postexertional malaise, a subjective feeling of infection and neurocognitive disorders and is a more severe variant than CFS. Fukuda's 1994 CDC criteria are adequate to make a distinction between patients with ME/CFS and CF, while ME/CFS patients should be subdivided into those with and without postexertional malaise into ME and CFS, respectively. Different interrelated pathophysiological mechanisms play a role in ME/CFS, i.e. (1) inflammation and immune activation, (2) oxidative and nitrosative stress and lowered antioxidant defenses, (3) activation of cell signaling networks, e.g. nuclear factor ĸβ, the 2 9 ,5 9 -oligoadenylate/RNase-L and/or protein kinase R pathway, (4) a transition towards autoimmune reactions, and (5) bacterial translocation. The inflammatory biomarkers are higher in ME/CFS than in CF and higher in ME than in CFS. The above-mentioned pathways may explain the onset of characteristic ME/CFS symptoms, such as fatigue, malaise, autonomic symptoms, hyperalgesia, and neurocognitive symptoms. Different etiological factors may trigger ME/CFS/CF, e.g. viral and bacterial infections, and (auto)immune and inflammatory disorders, while psychosocial and physical stressors act as modulating factors. New pathophysiologically driven drug candidates for ME and CFS are discussed which target the pathways that play a role in ME/CFS.
A link between Alzheimer's disease (AD) and an excess presence of oxidant free radicals in the brain has frequently been reported. It is generally assumed that such oxidative stress and related cellular damage is caused by inflammatory changes in the brain and is consequent to amyloid deposition. This review makes the argument that elevated oxidative stress in AD is an early causal event in the initiation and advancement of this disease. Oxidative stress can be decreased by enhancing antioxidant enzymes through activation of the cytoplasmic transcriptional factor (Nrf2)/ARE (antioxidant response element) pathway, and by dietary and endogenous antioxidant chemicals. Reduction in the binding ability of Nrf2 to ARE lowers antioxidant enzyme levels. Decreased levels of Nrf2 and augmentation of oxidative stress in AD suggest that the ROS-dependent mechanism of activating the Nrf2/ARE pathway has become unresponsive. A combination of agents that can either activate the Nrf2-ARE pathway by ROS-independent mechanisms, or by acting directly as antioxidant chemicals, may be necessary to reduce oxidative stress in AD. Earlier shortcomings of using individual antioxidants may be due to consideration of antioxidants as pharmacological agents, ignoring the fact that individual antioxidants can be transmuted in the highly oxidant milieu that is present in AD. Interactions between various cellular compartments may require simultaneous examination of more than one agent. The clinical utility of such a more integrative method can reveal interactive effects such as those found in nutritional research and this can compensate for any mechanistic shortcomings of simultaneous testing of more than a single agent.
Background & Aims
Oxidative stress and inflammation seem to be potential underlying mechanisms for telomere attrition. A lack of specific antioxidants is believed to increase free radical damage and a greater risk for telomere shortening. Our aim was to evaluate the relationship between diet and leukocyte telomere length in a cross-sectional study of children and adolescents. We hypothesized that dietary total antioxidant capacity would be positively associated with telomere length.
Methods
Telomere length was measured by quantitative real-time polymerase chain reaction in 287 participants (55% males, 6–18 years), who were randomly selected from the GENOI study.
Results
A positive correlation between dietary total antioxidant capacity and telomere length (r=0.157, p=0.007) was found after adjustment for age and energy intake. However, higher white bread consumption was associated with shorter telomeres (β=-0.204, p=0.002) in fully-adjusted models. Interestingly, those individuals who had simultaneously higher dietary total antioxidant capacity and lower white bread consumption significantly presented the longest telomeres. Moreover, the multivariable-adjusted odds ratio for very short telomeres was 0.30 for dietary total antioxidant capacity (p=0.023) and 1.37 for white bread (p=0.025).
Conclusion
It was concluded that longer telomeres were associated with higher dietary total antioxidant capacity and lower white bread consumption in S2panish children and adolescents. These findings might open a new line of investigation about the potential role of an antioxidant diet in maintaining telomere length.
Background:
Increasing evidence showed that telomere length was shorter in age-related diseases, but the mechanism of this phenomenon is still unclear.
Aim:
To determine whether telomere shortening occurs in Type 1 diabetes (T1D) and Type 2 diabetes (T2D), and explore the effect of antioxidant status on the telomere length.
Subjects and methods:
T2D patients (no.=62), T1D patients (no.=34), and non-diabetic subjects used as control (CTL) (no.=40) were included in this study. Leukocyte telomere length ratio (T/S ratio) was measured using a quantitative PCR and analyzed. Antioxidant status was estimated by human 8-hydroxy-desoxyguanosine quantization. Other biomarkers, such as fasting plasma glucose, fasting insulin, glycated hemoglobin (HbA1c) and lipid profile were also measured.
Results:
Compared with CTL group [T/S ratio (mean ± SD), 2.39 ± 0.55], leukocyte telomere length was significantly shorter in T2D group (1.67 ± 0.50) and T1D group (1.77 ± 0.50). 8-OHdG that indicated oxidative stress was significantly higher in T2D (2.99 ± 0.85 ng/ml) and T1D (2.03 ± 0.92 ng/ml) group than in CTL group (0.90 ± 0.46 ng/ml). T/S ratio was significantly negatively correlated with age, waist circumference, waist-to-hip ratio, diastolic blood pressure, fasting plasma glucose, HbA1c, homeostasis model assessment of insulin resistance and 8- OHdG in the whole population. 8-OHdG was independent risk factor for telomere shortening in both T1D (p=0.018) and T2D group (p=0.022).
Conclusions:
In our study, shorter telomere length and increased oxidative stress were observed in both T1D and T2D. Older people with central obesity, hyperglycemia, insulin resistance and severe antioxidant status tended to have shorter telomere length. In addition, 8- OHdG was an independent predictor for telomere length for both T1D and T2D patients.
Shorter telomeres have been associated with poor health behaviors, age-related diseases, and early mortality. Telomere length is regulated by the enzyme telomerase, and is linked to exposure to proinflammatory cytokines and oxidative stress. In our recent randomized controlled trial, omega-3 (n-3) polyunsaturated fatty acid (PUFA) supplementation lowered the concentration of serum proinflammatory cytokines. This study assessed whether n-3 PUFA supplementation also affected leukocyte telomere length, telomerase, and oxidative stress. In addition to testing for group differences, changes in the continuous n-6:n-3 PUFA ratio were assessed to account for individual differences in adherence, absorption, and metabolism. The double-blind four-month trial included 106 healthy sedentary overweight middle-aged and older adults who received (1) 2.5g/day n-3 PUFAs, (2) l.25g/day n-3 PUFAs, or (3) placebo capsules that mirrored the proportions of fatty acids in the typical American diet. Supplementation significantly lowered oxidative stress as measured by F2-isoprostanes (p=0.02). The estimated geometric mean log-F2-isoprostanes values were 15% lower in the two supplemented groups compared to placebo. Although group differences for telomerase and telomere length were nonsignificant, changes in the n-6:n-3 PUFA plasma ratios helped clarify the intervention's impact: telomere length increased with decreasing n-6:n-3 ratios, p=0.02. The data suggest that lower n-6:n-3 PUFA ratios can impact cell aging. The triad of inflammation, oxidative stress, and immune cell aging represents important pre-disease mechanisms that may be ameliorated through nutritional interventions. This translational research broadens our understanding of the potential impact of the n-6:n-3 PUFA balance. ClinicalTrials.gov identifier: NCT00385723.
Telomeres are located at the end of chromosomes. They are composed of repetitive TTAGGG tandem repeats and associated proteins of crucial importance for telomere function. Telomeric DNA is shortened by each cell division until a critical length is achieved and the cell enters senescence and eventually apoptosis. Telomeres are therefore considered a 'biological clock' of the cell. Telomerase adds nucleotides to telomeric DNA thereby contributing to telomere maintenance, genomic stability, functions, and proliferative capacity of the cell. In certain rare forms of progeria, point mutations within the telomere lead to accelerated telomere attrition and premature aging. Endogenous factors causing telomere shortening are aging, inflammation, and oxidative stress. Leukocyte telomere length (LTL) shortening is inhibited by estrogen and endogenous antioxidants. Accelerated telomere attrition is associated with cardiovascular risk factors such as age, gender, obesity, smoking, sedentary life-style, excess alcohol intake, and even mental stress. Cardiovascular (CV) diseases and CV aging are usually but not invariably associated with shorter telomeres than in healthy subjects. LTL appears to be a biomarker of CV aging, reflecting the cumulative burden of endogenous and exogenous factors negatively affecting LTL. Whether accelerated telomere shortening is cause or consequence of CV aging and disease is not clear.
In order to identify new markers of vascular cell senescence with potential in vivo implications, primary cultured endothelial cells, including human umbilical vein endothelial cells (HUVECs), human aortic endothelial cells (HAECs), human coronary artery endothelial cells (HCAECs) and ex vivo circulating angiogenic cells (CACs), were analysed for microRNA (miR) expression. Among the 367 profiled miRs in HUVECs, miR-146a, miR-9, miR-204 and miR-367 showed the highest up-regulation in senescent cells. Their predicted target genes belong to nine common pathways, including Toll-like receptor signalling (TLR) that plays a pivotal role in inflammatory response, a key feature of senescence (inflammaging). MiR-146a was the most up-regulated miR in the validation analysis (>10-fold). Mimic and antagomir transfection confirmed TLR's IL-1 receptor-associated kinase (IRAK1) protein modulation in both young and senescent cells. Significant correlations were observed among miR-146a expression and β-galactosidase expression, telomere length and telomerase activity. MiR-146a hyper-expression was also validated in senescent HAECs (>4-fold) and HCAECs (>30-fold). We recently showed that CACs from patients with chronic heart failure (CHF) presented a distinguishing feature of senescence. Therefore, we also included miR-146a expression determination in CACs from 37 CHF patients and 35 healthy control subjects (CTR) for this study. Interestingly, a 1,000-fold increased expression of miR-146a was observed in CACs of CHF patients compared to CTR, along with decreased expression of IRAK1 protein. Moreover, significant correlations among miR-146a expression, telomere length and telomerase activity were observed. Overall, our findings indicate that miR-146a is a marker of a senescence-associated pro-inflammatory status in vascular remodelling cells.
The incidence of chronic diseases such as cardiovascular diseases is lower in Mediterranean Southern Europe than Northern Europe. This may be due to a lower level of oxidative stress and a higher antioxidant status in people living around the Mediterranean Sea. Oxidative stress may influence the rate of shortening of telomeres, the nucleoprotein structures at the ends of chromosomes. We compared leukocyte telomere length (LTL) in elderly men from Northern and Southern Europe and investigated the possible relationship between LTL and indicators of oxidative stress and antioxidant status. We examined 143 elderly Dutch men (mean age 83.9 years) and 109 Greek elderly men (mean age 84.6 years) and found that the Greek men had significantly longer telomeres (geometric mean 4.95 kbp, 95% confidence interval (CI): 4.71-5.23 kbp) compared to the men from the Netherlands (4.76 kbp, 95% CI: 4.55-4.98 kbp; P=0.001). Age was inversely associated with LTL (β=-0.10, P=0.31 in Cretan men and β=-0.19, P=0.02 in Dutch men). In all men LTL was not related to indicators of oxidative stress and plasma antioxidants. However, the endogenous antioxidants serum albumin (β=0.18, P=0.007) and uric acid (β=0.13, P=0.045) were positively associated with LTL. The age-adjusted difference between Crete and Zutphen was reduced by 25% after adjustment for serum albumin and uric acid. We conclude that Greek elderly men have significantly longer LTL compared to Dutch counterparts. The endogenous antioxidants albumin and uric acid were positively associated with longer telomeres.
Micro RNAs (miRNAs) constitute a unique class of small, non-coding ribonucleic acids (RNAs) that regulate gene expression at the post-transcriptional level. The presence of two inducible miRNAs, miRNA-125b and miRNA-146a, involved in respectively, astroglial cell proliferation and in the innate immune and inflammatory response, is significantly up-regulated in human neurological disorders including Alzheimer's disease (AD). In this study we analyzed abundances miRNA-125b and miRNA-146a in magnesium-, iron-, gallium, and aluminum-sulfate-stressed human-astroglial (HAG) cells, a structural and immune-responsive brain cell type. The combination of iron- plus aluminum-sulfate was found to be significantly synergistic in up-regulating reactive oxygen species (ROS) abundance, NF-кB-DNA binding and miRNA-125b and miRNA-146a expression. Treatment of metal-sulfate stressed HAG cells with the antioxidant phenyl butyl nitrone (PBN) or the NF-кB inhibitors curcumin, the metal chelator-anti-oxidant pyrollidine dithiocarbamate (PDTC), or the resveratrol analog CAY10512, abrogated both NF-кB signaling and induction of these miRNAs. Our observations further illustrate the potential of physiologically relevant amounts of aluminum and iron sulfates to synergistically up-regulate specific miRNAs known to contribute to AD-relevant pathogenetic mechanisms, and suggest that antioxidants or NF-кB inhibitors may be useful to quench metal-sulfate triggered genotoxicity.
Background:
Telomere signaling plays a role in regulating cardiomyocyte apoptosis during cardiac dysfunction. In this study, we investigated the effects of epigallocatechin gallate (EGCG), the major component of polyphenols in green tea, on telomere dependent apoptotic signal in pressure overload cardiac hypertrophy.
Methods and results:
Cardiac hypertrophy in rats was established by abdominal aortic constriction (AC). EGCG 50, 100 mg/kg, quercetin (Que) 100mg/kg, captopril (Cap) 50mg/kg, losartan (Los) 30 mg/kg and carvedilol (Carv) 30 mg/kg was intragastrically administered for 6 weeks. Three, five and 7 weeks after aortic constriction, the heart weight indices increased progressively. Malondialdehyde (MDA) contents progressively increased, while superoxide dismutase (SOD) activities decreased. Progressive cardiomyocyte apoptosis and telomere attrition were also found. Although no significant alteration of telomerase reverse transcriptase (TERT) mRNA was found till 7 weeks after aortic constriction, progressive upregulation of p53, c-myc and downregulation of bcl-2, telomere repeat-binding factor 2(TRF(2)) were seen. EGCG, quercetin, captopril, losartan and carvedilol markedly reduced heart weight indices and apoptotic cardiomyocyte in hypertrophic myocardium, but they had different effects on apoptotic related proteins bcl-2, p53 and c-myc. EGCG, quercetin and carvedilol, have potent antioxidant effects as evidenced by reduction of MDA contents and resumption of SOD activities. EGCG, quercetin and carvedilol could prevent telomere attrition and telomere repeat-binding factor 2 (TRF(2)) loss remarkably, whereas captopril and losartan had no effect on oxidative stress and telomere signal.
Conclusions:
Pressure overload induced cardiac hypertrophy initiates oxidative stress, induces telomere repeat-binding factor 2 loss and accelerates telomere shortening in hypertrophic myocardium. EGCG, quercetin and carvedilol with potent antioxidant effect, may inhibit cardiac myocyte apoptosis by preventing telomere shortening and telomere repeat-binding factor 2 (TRF(2)) loss.
Many studies have shown that short telomere length (TL) is associated with high oxidative stress and various age-related diseases. Parkinson's disease (PD) is an age-related disease, and although its pathogenic mechanism is uncertain, oxidative stress is believed to be implicated in this pathology. The aim of this case-control study was to assess both TL and the different markers of oxidative stress in elderly patients with PD compared to age control subjects.
20 PD patients and 15 age-matched controls, >65 years were studied. TL was measured by Southern blotting from DNA samples extracted from white blood cells. Superoxide dismutase (SOD) activity and plasma levels of total glutathione and protein carbonyls were determined.
There was a trend for lower TL in PD patients: 6.06 ± 0.81 kb in PD versus 6.45 ± 0.73 kb in controls (p = 0.08). No significant difference was found between the two groups in terms of oxidative stress markers. In controls, age was the main determinant of telomere shortening (r = -0.547; p = 0.03) whereas, in PD patients, telomere shortening was mainly dependent on plasmatic concentrations of carbonyl proteins (r= -0.544; p=0.044). In PD patients, a negative association was observed between plasma carbonyl protein levels and SOD activity (r= -0.622, p=0.004).
In PD, TL is shorter in presence of high oxidative stress as measured by carbonyl protein levels. The absence of telomere attrition with age among patients with PD could reflect a telomere regulation by mechanisms other than age.
The aim of this study was to determine leukocyte telomere length (LTL) in individuals with periodontitis and controls, exploring its relationship with systemic inflammation and oxidative stress. Five hundred sixty-three participants were recruited for this case-control study: 356 subjects with and 207 subjects without periodontitis. LTL was measured by a qPCR technique from leukocytes' DNA. Global measures of oxidative stress (reactive oxygen metabolites) and biological antioxidant potential in plasma were performed together with high-sensitivity assays for C-reactive protein (CRP). Leukocyte counts and lipid profiles were performed using standard biochemistry. Cases had higher levels of CRP (2.1±3.7mg/L vs 1.3±5.4mg/L, P<0.001) and reactive oxygen metabolites (378.1±121.1 U Carr vs 277.4±108.6 U Carr, P<0.001) compared to controls. Overall, cases had shorter LTL with respect to controls (1.23±0.42 vs 1.12±0.31T/S ratio, P=0.006), independent of age, gender, ethnicity, and smoking habit. When divided by subgroup of periodontal diagnosis (chronic, n=285; aggressive, n=71), only chronic cases displayed shorter LTL (P=0.01). LTL was negatively correlated with age (P=0.001; R=-0.2), oxidative stress (P=0.008; R=-0.2), and severity of periodontitis (P=0.003; R=-0.2) in both the whole population and the subgroups (cases and controls). We conclude that shorter telomere lengths are associated with a diagnosis of periodontitis and their measures correlate with the oxidative stress and severity of disease.
Oxidative stress plays a pathological role in the development of heart failure. This study examined telomere biology in heart/muscle-specific manganese superoxide dismutase-deficient mice (H/M-SOD2(-/-)), which develop progressive congestive heart failure and exhibit pathology typical of dilated cardiomyopathy. EUK-8 (25mg/kg/day), a superoxide dismutase and catalase mimetic, was administered to H/M-SOD2(-/-) mice for four weeks beginning at 8 weeks of age. Telomere length, telomerase activity, telomere-associated proteins, and cell death signals were assessed in hearts from control wild-type mice (H/M-Sod2 (lox/ lox)) and H/M-SOD2(-/-) mice either treated or untreated with EUK-8. While cardiac function was unchanged in these experimental mice, the end-diastolic dimension in H/M-SOD2(-/-) mice was notably dilated and could be significantly reduced by EUK-8 treatment. At the end of the study, no shortening of telomere length was observed in heart tissues from all mice tested, but telomerase activity was decreased in heart tissue from H/M-SOD2(-/-) mice compared to control mice. Protein expression for telomerase reverse transcriptase and telomere repeat binding factor 2 was also downregulated in H/M-SOD2(-/-) heart tissue as was expression of phospho-Akt, insulin-like growth factor, and endothelial nitric oxide synthase. Expression levels of Sirt1, a lifespan modulator, were enhanced while FoxO3a was depressed in H/M-SOD2(-/-) hearts. All of the changes seen in H/M-SOD2(-/-) heart tissue could be inhibited by EUK-8 treatment. Taken together, the results suggest that oxidant stress might affect myocardial telomerase activity and telomere-associated proteins. Telomerase may therefore play a pivotal role in antioxidant defense mechanisms, and may be useful as a novel therapeutic tool for treating human heart failure.
Xeroderma pigmentosum B (XPB/ERCC3/p89) is an ATP-dependent 3'-->5' directed DNA helicase involved in basal RNA transcription and the nucleotide excision repair (NER) pathway. While the role of NER in alleviating oxidative DNA damage has been acknowledged it remains poorly understood. To study the involvement of XPB in repair of oxidative DNA damage, we utilized primary fibroblasts from a patient suffering from XP with Cockayne syndrome and hydrogen peroxide (H(2)O(2)) to induce oxidative stress. Mutant cells retained higher viability and cell cycle dysfunction after H(2)O(2) exposure. Cytokinesis blocked micronucleus assay revealed increased genome instability induced by H(2)O(2). Single cell gel electrophoresis (comet) assay showed that the missense mutation caused a reduced repair capacity for oxidative DNA damage. Mutant fibroblasts also displayed decreased population doubling rate, increased telomere attrition rate and early emergence of senescent characteristics under chronic low dose exposure to H(2)O(2). Fibroblasts from a heterozygous individual displayed intermediate traits in some assays and normal traits in others, indicating possible copy number dependence. The results show that a deficiency in functional XPB paradoxically renders cells more sensitive to the genotoxic effects of oxidative stress while reducing the cytotoxic effects. These findings have implications in the mechanisms of DNA repair, mutagenesis and carcinogenesis and ageing in normal physiological systems.
Shortening of mean telomere length (TL) in white blood cells is correlated with the development of coronary heart disease (CHD) and with increased mortality due to infectious disease. The goal of the present study was to investigate whether telomere shortening in CHD is restricted to specific peripheral blood lymphocyte and/or myeloid cell subpopulations. Results were correlated to TL in CD34+ hematopoietic peripheral blood stem cells and progenitor cells obtained from the same individual patients.
TL was measured by multicolor flow cytometry-fluorescent in situ hybridization in 12 leukocyte subpopulations after immunomagnetic bead sorting. We investigated TL in 14 young (mean age 25 years) and 13 older (mean age 65 years) healthy male volunteers and in 25 age-matched patients with CHD (mean age 65 years). We show that TL in granulocytes and monocytes mirrors TL of CD34+ peripheral blood stem cells and progenitor cells extremely well (r=0.95, P<0.0001) in patients and in healthy adults. TL was approximately 0.5 kilobases (kb) shorter in leukocytes from patients with CHD than in their age-matched control subjects. This difference was identical for CD34+ peripheral blood stem cells and progenitor cells, monocytes, granulocytes, B lymphocytes, and CD4+ T cells, including their memory and naïve subpopulations. Surprisingly, only in cytotoxic CD8+ T lymphocytes, we found a substantially increased TL deficit of 1.0 kb in CHD patients as opposed to control subjects. Further analysis revealed that TL shortening was particularly pronounced in CD8+CD28(-) T cells obtained from cytomegalovirus-seropositive CHD patients, whereas such a difference was not observed in healthy cytomegalovirus-positive as opposed to cytomegalovirus-negative control subjects. Finally, TL shortening of CD8+CD45(RA+) T cells was correlated with the decrease in left ventricular function in CHD patients (r=0.629, P=0.001).
Telomere shortening in patients with CHD could potentially be attributed to either inherited TL shortening or acquired accelerated telomere shortening restricted to the hematopoietic system, which affects the baseline TL of all peripheral blood cell populations, including peripheral blood stem cells and progenitor cells. In addition, cytomegalovirus-seropositive patients but not healthy control subjects exhibited further shortening of their cytotoxic T lymphocytes. Surprisingly, TL shortening of CD8+ T lymphocytes in CHD patients demonstrated a very strong correlation with cardiac dysfunction, which suggests a mechanistic link between CHD and immunosenescence.
Aging is associated with a rise in intracellular reactive oxygen species (ROS) and a loss of telomerase reverse transcriptase activity. Incubation with H2O2 induced the nuclear export of telomerase reverse transcriptase (TERT) into the cytosol in a Src-family kinase-dependent manner. Therefore, we investigated the hypothesis that age-related increase in reactive oxygen species (ROS) may induce the nuclear export of TERT and contribute to endothelial cell senescence. Continuous cultivation of endothelial cells resulted in an increased endogenous formation of ROS starting after 29 population doublings (PDL). This increase was accompanied by mitochondrial DNA damage and preceded the onset of replicative senescence at PDL 37. Along with the enhanced formation of ROS, we detected an export of nuclear TERT protein from the nucleus into the cytoplasm and an activation of the Src-kinase. Moreover, the induction of premature senescence by low concentrations of H2O2 was completely blocked with the Src-family kinase inhibitor PP2, suggesting a crucial role for Src-family kinases in the induction of endothelial cell aging. Incubation with the antioxidant N-acetylcysteine, from PDL 26, reduced the intracellular ROS formation and prevented mitochondrial DNA damage. Likewise, nuclear export of TERT protein, loss in the overall TERT activity, and the onset of replicative senescence were delayed by incubation with N-acetylcysteine. Low doses of the statin, atorvastatin (0.1 micromol/L), had also effects similar to those of N-acetylcysteine. We conclude that both antioxidants and statins can delay the onset of replicative senescence by counteracting the increased ROS production linked to aging of endothelial cells.