No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Endothelial Progenitor Cell Function, Apoptosis, and Telomere Length in Overweight/Obese Humans
Abstract
Excess adiposity is associated with increased cardiovascular morbidity and mortality. Endothelial progenitor cells (EPCs) play an important role in vascular repair. We tested the hypothesis that increased adiposity is associated with EPC dysfunction, characterized by diminished capacity to release angiogenic cytokines, increased apoptotic susceptibility, reduced cell migration, and shorter telomere length. A total of 67 middle-aged and older adults (42-67 years) were studied: 25 normal weight (normal weight; BMI: 18.5-24.9 kg/m(2)) and 42 overweight/obese (overweight/obese; BMI: 25.0-34.9 kg/m(2)). Cells with phenotypic EPC characteristics were isolated from peripheral blood. EPC release of vascular endothelial growth factor (VEGF) and granulocyte colony-stimulating factor (G-CSF) was determined in the absence and presence of phytohemagglutinin (10 microg/ml). Intracellular active caspase-3 and cytochrome c concentrations were determined by immunoassay. Migratory activity of EPCs in response to VEGF (2 ng/ml) and stromal cell-derived factor-1alpha (SDF-1alpha; 10 ng/ml) was determined by Boyden chamber. Telomere length was assessed by Southern hybridization. Phytohemagglutinin-stimulated release of VEGF (90.6 +/- 7.6 vs. 127.2 +/- 11.6 pg/ml) and G-CSF (896.1 +/- 77.4 vs. 1,176.3 +/- 126.3 pg/ml) was ~25% lower (P < 0.05) in EPCs from overweight/obese vs. normal weight subjects. Staurosporine induced a ~30% greater (P < 0.05) increase in active caspase-3 in EPCs from overweight/obese (2.8 +/- 0.2 ng/ml) compared with normal weight (2.2 +/- 0.2) subjects. There were no significant differences in EPC migration to either VEGF or SDF-1alpha. Telomere length did not differ between groups. These results indicate that increased adiposity adversely affects the ability of EPCs to release proangiogenic cytokines and resist apoptosis, potentially compromising their reparative potential.
... However, whether these metabolic conditions are associated with telomere length, as well as the direction of these relations, are unclear. Studies have shown associations between higher body mass index (BMI) [14,15,16,17] or T2D [12,18,19,20] and telomere shortening, although some have reported no relation [21,22,23]. While these associations may be explained by heightened oxidative stress and inflammation among obese or diabetic individuals, which promote telomere erosion, recent findings have suggested telomeres may play a role in the development of obesity or T2D [24,25]. ...
... While our study is the first to examine the association between genetic predisposition to higher BMI or T2D and telomere length, many cross-sectional studies have directly examined the relation with these metabolic conditions. For BMI, some studies [14,15,16,17,55,56,60,61,62], including the present analysis, observed an inverse association with telomere length, while others reported no association [8,21,22,63]. Similarly for T2D, most studies [12,18,19,20,57,58,59,64,65], including the present analysis, observed an inverse association despite a large variation in the strength of the relation. Although the reasons for these discrepancies are unclear, studies differed in sample size and population characteristics. ...
... First, unmeasured confounders may have influenced findings. For example, several studies reported only unadjusted [22,23,58,62] or age-adjusted results [12,15,57,63], increasing the possibility of unmeasured confounding by factors such as age, smoking, or physical activity (i.e., potential predictors of higher BMI or T2D and telomere length). Second, crosssectional analyses were unable to test the direction of the association between higher BMI or T2D and telomere shortening, although several studies hypothesized that telomere shortening may be a consequence of higher body mass or T2D due to elevated oxidative stress and inflammation [10,11,12,13]. ...
Although cross-sectional studies have linked higher body mass index (BMI) and type 2 diabetes (T2D) to shortened telomeres, whether these metabolic conditions play a causal role in telomere biology is unknown. We therefore examined whether genetic predisposition to higher BMI or T2D was associated with shortened leukocyte telomere length (LTL).
We conducted an analysis of 3,968 women of European ancestry aged 43-70 years from the Nurses' Health Study, who were selected as cases or controls in genome-wide association studies and studies of telomeres and disease. Pre-diagnostic relative telomere length in peripheral blood leukocytes, collected in 1989-1990, was measured by quantitative PCR. We combined information from multiple risk variants by calculating genetic risk scores based on 32 polymorphisms near 32 loci for BMI, and 36 polymorphisms near 35 loci for T2D.
After adjustment for age and case-control status, there was no association between the BMI genetic risk score and LTL (β per standard deviation increase: -0.01; SE: 0.02; P = 0.52). Similarly, the T2D genetic score was not associated with LTL (β per standard deviation increase: -0.006; SE: 0.02; P = 0.69).
In this population of middle-aged and older women of European ancestry, those genetically predisposed to higher BMI or T2D did not possess shortened telomeres. Although we cannot exclude weak or modest effects, our findings do not support a causal relation of strong magnitude between these metabolic conditions and telomere dynamics.
... A small number of studies have investigated the relationship between TL and obesity. Some cross-sectional studies have reported significant associations between TL and obesity (16)(17)(18) but some did not (11,19,20). The only prospective study reported an increased TL in rectal mucosa of people who lost weight (21). ...
... There are a handful of previous investigations on the association between TL and obesityrelated traits, all of which considered obesity being a risk factor for shorter TL. Some studies found significant associations between shorter TL and obesity or higher levels of its related quantitative measures (16,17,25,26) whereas others did not (19,20). Yet no study has been conducted in the elderly. ...
... We also observed a weak but negative relationship between TL and BMI, and a significantly negative association with % body fat in our cohort of elderly. Using BMI ≥ 30 kg/m 2 to define obesity, MacEneaney et al. (19) reported no difference in TL between normal and overweight/obese individuals. One study by Valdes et al. (16) reported a negative correlation (r = −0.124, ...
Objective:
Obesity and shorter telomeres are commonly associated with elevated risk for age-related diseases and mortality. Whether telomere length (TL) may be associated with obesity or variations in adiposity is not well established. Therefore, we set out to test the hypothesis that TL may be a risk factor for increased adiposity using data from a large population-based cohort study.
Design:
Levels of adiposity were assessed in six ways (obesity status, body mass index (BMI), the percentage of body fat or % body fat, leptin, visceral and subcutaneous fat mass) in 2721 elderly subjects (42% black and 58% white). Associations between TL measured in leukocytes at baseline and adiposity traits measured at baseline, and three of these traits after 7 years of follow-up were tested using regression models adjusting for important covariates. Additionally, we look at weight changes and relative changes in BMI and % body fat between baseline and follow-up.
Results:
At baseline, TL was negatively associated with % body fat (ß=-0.35±0.09, P=0.001) and subcutaneous fat (ß=-2.66±1.07, P=0.01), and positively associated with leptin after adjusting for % body fat (ß=0.32±0.14, P=0.001), but not with obesity, BMI or visceral fat. Prospective analyses showed that longer TL was associated with positive percent change between baseline and 7-year follow-up for both BMI (ß=0.48±0.20, P=0.01) and % body fat (ß=0.42±0.23, P=0.05).
Conclusion:
Our study suggests that shorter TL may be a risk factor for increased adiposity. Coupling with previous reports on their reversed roles, the relationship between adiposity and TL may be complicated and may warrant more prospective studies.
... Excessive body weight facilitates endothelial dysfunction and atherosclerosis through increased lipid storage (Rocha and Libby, 2009) and chronic low-grade inflammation (MacEneaney et al., 2010;Lumeng and Saltiel, 2011). Under normal physiological conditions, vasodilation (and vasoconstriction) is regulated by the secretion of factors derived, among others, from endothelial cells (Shepherd and Katusić, 1991). ...
... High BMI may affect endothelium in a few ways. Endothelial progenitor cells of individuals with obesity release less proangiogenic factors and are more susceptible to apoptotic stimuli (MacEneaney et al., 2010). Second, high BMI results in a persistent proinflammatory state, leading in turn to endothelial damage (Rocha and Libby, 2009). ...
Background and objectives
Obesity is a risk factor for cognitive decline. Probable mechanisms involve inflammation and cerebrovascular dysfunction, leading to diminished cerebral blood flow (CBF) and cerebrovascular reactivity (CVR). The hippocampus, crucially involved in memory processing and thus relevant to many types of dementia, poses a challenge in studies of perfusion and CVR, due to its location, small size, and complex shape. We examined the relationships between body mass index (BMI) and hippocampal resting CBF and CVR to carbon dioxide (CVR CO2 ) in a group of cognitively normal middle-aged and older adults.
Methods
Our study was a retrospective analysis of prospectively collected data. Subjects were enrolled for studies assessing the role of hippocampal hemodynamics as a biomarker for AD among cognitively healthy elderly individuals (age > 50). Participants without cognitive impairment, stroke, and active substance abuse were recruited between January 2008 and November 2017 at the NYU Grossman School of Medicine, former Center for Brain Health. All subjects underwent medical, psychiatric, and neurological assessments, blood tests, and MRI examinations. To estimate CVR, we increased their carbon dioxide levels using a rebreathing protocol. Relationships between BMI and brain measures were tested using linear regression.
Results
Our group ( n = 331) consisted of 60.4% women (age 68.8 ± 7.5 years; education 16.8 ± 2.2 years) and 39.6% men (age 70.4 ± 6.4 years; education 16.9 ± 2.4 years). Approximately 22% of them ( n = 73) were obese. BMI was inversely associated with CVR CO2 (β = −0.12, unstandardized B = −0.06, 95% CI −0.11, −0.004). A similar relationship was observed after excluding subjects with diabetes and insulin resistance (β = −0.15, unstandardized B = −0.08, 95% CI −0.16, −0.000). In the entire group, BMI was more strongly related to hippocampal CVR CO2 in women (β = −0.20, unstandardized B = −0.08, 95% CI −0.13, −0.02).
Discussion
These findings lend support to the notion that obesity is a risk factor for hippocampal hemodynamic impairment and suggest targeting obesity as an important prevention strategy. Prospective studies assessing the effects of weight loss on brain hemodynamic measures and inflammation are warranted.
... Overweight and obesity are associated with an increased risk of cardiovascular diseases, such as stroke, coronary atherosclerosis, congestive heart failure, and arrhythmias [1][2][3][4][5][6][7]. Abundant data have demonstrated that overweight or obesity may contribute to endothelial damage and dysfunction [1,2,[6][7][8][9], which are believed to be involved in the pathogenesis and progression of cardiovascular diseases [10]. ...
... Overweight and obesity are associated with an increased risk of cardiovascular diseases, such as stroke, coronary atherosclerosis, congestive heart failure, and arrhythmias [1][2][3][4][5][6][7]. Abundant data have demonstrated that overweight or obesity may contribute to endothelial damage and dysfunction [1,2,[6][7][8][9], which are believed to be involved in the pathogenesis and progression of cardiovascular diseases [10]. Therefore, it is urgent to identify a method to restore endothelial dysfunction in overweight or obese individuals. ...
Endothelial progenitor cells (EPCs) have endogenous endothelium-reparative potential, but obesity impairs EPCs. Overweight premenopausal women have a normal number of circulating EPCs with functional activity, but whether EPCs in overweight postmenopausal women can repair obesity-related endothelial damage requires further investigation. For this purpose, we examined the function and number of circulating EPCs, evaluated vascular endothelial function, and explored the underlying mechanism. Compared with normal weight or overweight age-matched men, postmenopausal women (overweight or normal weight) had a diminished number of circulating EPCs and impaired vascular endothelial function, as detected by flow-mediated dilatation. Moreover, GTCPH I expression and the nitric oxide level in overweight postmenopausal women and men were significantly decreased. Together, our findings demonstrate that the number or function of circulating EPCs and endothelial function, which is partially regulated by the GTCPH I/BH4 signaling pathway, is not preserved in overweight postmenopausal women. The GTCPH I/BH4 pathway in circulating EPCs may be a potential therapeutic target for endothelial injury in overweight postmenopausal women.
... It is well established that obesity is associated with decreased numbers of EPCs [75][76][77][78][79] . The number of circulating EPCs is lower in obese compared with overweight and normal weight subjects, while EPCs colony forming capacity is blunted in overweight and obese compared with normal weight subjects [76] . ...
... Tobler et al [77] also stated that reduced numbers of EPCs along with their premature senescence might contribute to the development and progression of vascular dysfunction in obesity. Furthermore, the function of EPCs in obesity is impaired either by the impaired ability of circulating EPCs to release proangiogenic growth factors compared with normal weight adults and by the lower EPC resistance to an apoptotic stimulus in overweight and obese compared to normal weight [78] . Interestingly, low EPCs levels [75] and their functional deficiency [79] can be reversed after significant weight reduction. ...
Circulating bone-marrow-derived cells, named endothelial progenitor cells (EPCs), are capable of maintaining, generating, and replacing terminally differentiated cells within their own specific tissue as a consequence of physiological cell turnover or tissue damage due to injury. Endothelium maintenance and restoration of normal endothelial cell function is guaranteed by a complex physiological procedure in which EPCs play a significant role. Decreased number of peripheral blood EPCs has been associated with endothelial dysfunction and high cardiovascular risk. In this review, we initially report current knowledge with regard to the role of EPCs in healthy subjects and the clinical value of EPCs in different disease populations such as arterial hypertension, obstructive sleep-apnea syndrome, obesity, diabetes mellitus, peripheral arterial disease, coronary artery disease, pulmonary hypertension, and heart failure. Recent studies have introduced the novel concept that physical activity, either performed as a single exercise session or performed as part of an exercise training program, results in a significant increase of circulating EPCs. In the second part of this review we provide preliminary evidence from recent studies investigating the effects of acute and long-term exercise in healthy subjects and athletes as well as in disease populations.
... The ESTHER cohort study indicated that adiposity and weight gain during adulthood are associated with shortened telomeres [26]. However, several studies showed no significant associations between telomere length and anthropometric measures (BMI and visceral fat) [27,28]. In our study, the results showed that one unit increment of BMI was associated with a 7 bp shorten in LTL (95% CI -11.38 to -4.15, p < 0.001). ...
Background
Leukocyte telomere length (LTL) is a robust marker of biological aging, which is associated with obesity. Recently, the visceral adiposity index (VAI) has been proposed as an indicator of adipose distribution and function.
Objective
To evaluated the association between VAI and LTL in adult Americans.
Methods
There were 3193 participants in U.S. National Health and Nutrition Examination Surveys (1999–2002) included in this analysis. LTL was measured using quantitative PCR (qPCR) and expressed as telomere to single-gene copy ratio (T/S ratio). We performed multiple logistic regression models to explore the association between VAI and LTL by adjusting for potential confounders.
Results
Among all participants, VAI was associated with the shorter LTL (β: – 14.81, 95% CI – 22.28 to – 7.34, p < 0.001). There were significant differences of LTL in VAI tertiles (p < 0.001). Participants in the higher VAI tertile had the shorter LTL (1.26 ≤ VAI < 2.46: β = – 130.16, 95% CI [ – 183.44, – 76.87]; VAI ≥ 2.46: β = – 216.12, 95% CI [ – 216.12, – 81.42], p for trend: < 0.001) comparing with the lower VAI tertile. We also found a non-linear relationship between VAI and LTL. VAI was negatively correlated with LTL when VAI was less than 2.84.
Conclusions
The present study demonstrates that VAI is independently associated with telomere length. A higher VAI is associated with shorter LTL. The results suggest that VAI may provide prediction for LTL and account for accelerating the biological aging.
... This present animal study does not support the results from human studies showing a reduced LTL in obese people [39,40] and a preservation of TL upon regular endurance exercise [17]. Although some studies do not support an inverse relationship between TL and obesity [41][42][43], a recent meta-analysis calculated a significantly lower LTL in obese individuals than in normal-weight individuals [49]. Moreover, LTL was inversely correlated with BMI, body fat content, waist circumference, waist-to-hip ratio, and nuchal fat thickness. ...
(1) Obesity and exercise are believed to modify age-related telomere shortening by regulating telomerase and shelterins. Existing studies are inconsistent and limited to peripheral blood mononuclear cells (PBMCs) and selected solid tissues. (2) Female Sprague Dawley (SD) rats received either standard diet (ND) or high-fat diet (HFD). For 10 months, half of the animals from both diet groups performed 30 min running at 30 cm/s on five consecutive days followed by two days of rest (exeND, exeHFD). The remaining animals served as sedentary controls (coND, coHFD). Relative telomere length (RTL) and mRNA expression of telomerase (TERT) and the shelterins TERF-1 and TERF-2 were mapped in PBMCs and nine solid tissues. (3) At study end, coND and coHFD animals showed comparable RTL in most tissues with no systematic differences in TERT, TERF-1 and TERF-2 expression. Only visceral fat of coHFD animals showed reduced RTL and lower expression of TERT, TERF-1 and TERF-2. Exercise had heterogeneous effects on RTL in exeND and exeHFD animals with longer telomeres in aorta and large intestine, but shorter telomeres in PBMCs and liver. Telomere-regulating genes showed inconsistent expression patterns. (4) In conclusion, regular exercise or HFD cannot systematically modify RTL by regulating the expression of telomerase and shelterins.
... However, it may involve the increase in adiposity observed in these individuals, which could prevent EPCs from releasing proangiogenic factors including VEGF and granulocyte colony-stimulating factor while promoting the release of proapoptotic caspase-3, thereby compromising their reparative potential. 73 Despite a limited study sample size, our investigations are in line with others suggesting a close link between underlying cardiovascular disease risks and endothelial cell dysfunction. Several studies have observed sex-specific differences in the intracellular proteome and genome of human endothelial cells, which may affect endothelial cell function. ...
Background
A subpopulation of endothelial progenitor cells called endothelial colony‐forming cells (ECFCs) may offer a platform for cellular assessment in clinical studies because of their remarkable angiogenic and expansion potentials in vitro. Despite endothelial cell function being influenced by cardiovascular risk factors, no studies have yet provided a comprehensive proteomic profile to distinguish functional (ie, more angiogenic and expansive cells) versus dysfunctional circulating ECFCs of young adults. The aim of this study was to provide a detailed proteomic comparison between functional and dysfunctional ECFCs.
Methods and Results
Peripheral blood ECFCs were isolated from 11 subjects (45% men, aged 27±5 years) using Ficoll density gradient centrifugation. ECFCs expressed endothelial and progenitor surface markers and displayed cobblestone‐patterned morphology with clonal and angiogenic capacities in vitro. ECFCs were deemed dysfunctional if <1 closed tube formed during the in vitro tube formation assay and proliferation rate was <20%. Hierarchical functional clustering revealed distinct ECFC proteomic signatures between functional and dysfunctional ECFCs with changes in cellular mechanisms involved in exocytosis, vesicle transport, extracellular matrix organization, cell metabolism, and apoptosis. Targeted antiangiogenic proteins in dysfunctional ECFCs included SPARC (secreted protein acidic and rich in cysteine), CD36 (cluster of differentiation 36), LUM (lumican), and PTX3 (pentraxin‐related protein PYX3).
Conclusions
Circulating ECFCs with impaired angiogenesis and expansion capacities have a distinct proteomic profile and significant phenotype changes compared with highly angiogenic endothelial cells. Impaired angiogenesis in dysfunctional ECFCs may underlie the link between endothelial dysfunction and cardiovascular disease risks in young adults.
... These studies have yielded inconsistent results with a few early reports of small cohorts revealing an inverse relationship between higher BMI and CPC counts or function. [35][36][37][38][39] In contrast, more recent and relatively larger studies indicate that obesity is associated with higher CPC counts. [9][10][11][12] In this context, we have systematically studied the relationship between obesity and CPC counts in 2 large independent cohorts of individuals without and with CAD. ...
Objective
The underlying pathobiology of the paradoxical relationship between obesity and outcomes in coronary artery disease (CAD) is unclear. Our objective was to determine the association between obesity and circulating progenitor cell (CPC) counts—a measure of intrinsic regenerative capacity—in asymptomatic individuals and patients with CAD and its impact on the obesity paradox.
Approach and Results
CPCs were enumerated by flow cytometry as CD45 med+ cells expressing CD34+, CD133+, and CXCR4+ epitopes in 672 asymptomatic individuals (50 years of age; 28% obese) and 1277 CAD patients (66 years of age; 39% obese). The association between obesity and CPCs was analyzed using linear regression models. The association between obesity and CPCs with cardiovascular death/myocardial infarction events over 3.5-year follow-up in CAD was studied using Cox models. Obesity was independently associated with 16% to 34% higher CPC counts (CD34+, CD34+/CD133+, and CD34+/CXCR4+) in asymptomatic individuals. This association was not attenuated by systemic inflammation, insulin resistance, or secretion but partly attenuated by cardiorespiratory fitness and body composition. In patients with CAD, obesity was associated with 8% to 12% higher CPC counts and 30% lower risk of adverse outcomes. Compared with nonobese patients, only obese patients with high CPC counts (CD34+ cells ≥median, 1806 cells/mL) were at a lower risk (hazard ratio, 0.52 [95% CI, 0.31–0.88]), whereas those with low counts (<median) were at a similar risk (hazard ratio, 0.75 [95% CI, 0.48–1.15]).
Conclusions
Obesity is associated with higher CPC counts. The obesity paradox of improved outcomes with obesity in CAD is limited to patients with intact regenerative capacity who have CPC counts.
... In our study, we found that EPC counts were not significantly lower in overweight subgroups than in normal-weight subgroups (whether female or male), consistent with the results of MacEneaney et al. [17], who found that EPC counts were decreased in obese but not overweight subjects, while the colony-forming capacity of EPCs was impaired in overweight and obese adults compared with normal-weight adults [17]. A previous study found that EPC migratory capacity was not influenced by overweight or obesity [48]. On the other hand, Tsai et al. and Campis et al. revealed that the function of EPCs but not their number is reduced in the context of obesity uncomplicated by atherosclerosis [49,50]. ...
Background / Aims . Sexual differences exist in endothelial progenitor cells (EPCs), and various cardiovascular risk factors are associated with the preservation of endothelial function in premenopausal women. However, it is unclear whether differences in endothelial function and circulating EPCs exist between overweight premenopausal women and age-matched men. Methods . We compared EPC counting and functions in normal-weight and overweight premenopausal women and men, evaluated endothelial function in each group, and detected the expression of the guanosine triphosphate cyclohydrolase I (GTPCH I) pathway. Results . The number of EPCs was lower in the male group than in the female group, regardless of normal-weight or overweight status, and there was no significant difference between the different weight groups among females or males. Endothelial function and EPC migration and proliferation were preserved in overweight premenopausal women compared with overweight men as were nitric oxide (NO) levels in plasma and secreted by EPCs. Endothelial function, the circulating EPC population, and NO levels were not different between normal-weight and overweight premenopausal women. Flow-mediated dilatation was significantly correlated with EPC function, plasma NO levels, and EPC-secreted NO. Conclusions . This investigation provides the first evidence for sex-based differences in EPC activity and endothelial function in overweight middle-aged individuals; these differences are associated with alterations in NO production and may partly occur through downregulation of the GTPCH I pathway. The present results provide new insights into the mechanism underlying the preserved endothelial function in overweight premenopausal women and may uncover a potential therapeutic target for endothelial repair in overweight population.
... Valdes et al. found that LTL of obese women was 240 bp shorter than that of age-matched lean women (41). A couple of crosssectional studies showed a negative correlation between LTL and obesity (81,82), whereas others did not show significant associations between LTL and obesity (83,84). A recent meta-analysis showed there is a tendency toward demonstrating negative correlation between obesity and TL. ...
Stroke is one of the leading causes of death and disability worldwide. Age is associated with increased risk of stroke, while telomere length shortening plays a pivotal role in the process of aging. Moreover, telomere length shortening is associated with many risk factors of stroke in addition to age. Accumulated evidence shows that short leukocyte telomere length is not only associated with stroke occurrence but also associated with post-stroke recovery in the elderly population. In this review, we aimed to summarize the association between leukocyte telomere length and stroke, and discuss that telomere length might serve as a potential biomarker to predict the risk and prognosis of stroke.
... Interestingly, EPC proliferative capacity reflected reductions in circulating EPCs in obese compared to lean individuals [147]. The same group showed that the in vitro pro-angiogenic function of EPCs was also impaired with obesity in 50+year-old individuals, with impaired stimulated the release of both VEGF and G-CSF, which may be linked to the finding that these EPCs displayed higher expression of caspase-3, a pro-apoptotic intracellular signal [148]. In a murine model of obesity, obese animals displayed impaired in vitro angiogenesis, suppressed EPC mobilization in response to limb ischemia, and reduced incorporation into aortic vessels after LPS-induced vascular damage [149], confirmed by other animal models also showing impaired recovery of blood flow after limb ischemia accompanying the reductions in ischemia-induced PC mobilization [150]. ...
Background:
The endothelium plays an important role in cardiovascular regulation, from blood flow to platelet aggregation, immune cell infiltration and demargination. A dysfunctional endothelium leads to the onset and progression of Cardiovascular Disease (CVD). The aging endothelium displays significant alterations in function, such as reduced vasomotor functions and reduced angiogenic capabilities. This could be partly due to elevated levels of oxidative stress and reduced endothelial cell turnover. Circulating angiogenic cells, such as Endothelial Progenitor Cells (EPCs) play a significant role in maintaining endothelial health and function, by supporting endothelial cell proliferation, or via incorporation into the vasculature and differentiation into mature endothelial cells. However, these cells are reduced in number and function with age, which may contribute to the elevated CVD risk in this population. However, lifestyle factors, such as exercise, physical activity obesity, and dietary intake of omega-3 polyunsaturated fatty acids, nitrates, and antioxidants, significantly affect the number and function of these circulating angiogenic cells.
Conclusion:
This review will discuss the effects of advancing age on endothelial health and vascular regenerative capacity, as well as the influence of diet, exercise, and obesity on these cells, the mechanistic links and the subsequent impact on cardiovascular health.
... inflammation, and prevent adverse remodelling after PCI [2,14]. Successive reports of reduced abundance and functional impairment of circulating progenitor cells in obesity have led to the hypothesis that defective endothelial repair contributes to obesity-related cardiovascular disease [10,13,[15][16][17][18][19][20][21][22]. However, the current findings challenge these assumptions by demonstrating that endothelial regeneration remains preserved in mice with diet-induced obesity. ...
Introduction
Preservation of structural integrity of the endothelial monolayer and maintenance of endothelial cell function are of critical importance in preventing arterial thrombosis, restenosis and atherosclerosis. Obesity has been intimately linked with endothelial dysfunction and reports of reduced abundance and functional impairment of circulating progenitor cells in obesity have led to the suggestion that defective endothelial repair contributes to obesity‐related cardiovascular disease.
Methods
C57/Bl6 mice were fed a high fat diet for either 3 or 6 months to induce obesity, metabolic phenotyping was then carried out before femoral artery wire‐injury was performed. Endothelial regeneration was then quantified. Mononuclear cells and myeloid angiogenic cells were cultured and characterised for pro‐angiogenic properties.
Results
No impairment of endothelial regeneration following mechanical endothelial injury in diet‐induced obese mice when compared to chow fed controls was observed, despite the induction of an adverse metabolic phenotype characterised by glucose intolerance and insulin resistance. Dietary‐obese mice had increased numbers of circulating myeloid angiogenic cells, which retained normal functional properties including intact paracrine angiogenic effects.
Conclusion
Preserved endothelial regeneration despite metabolic dysregulation in dietary obese mice suggest that compensatory mechanisms mitigate the deleterious influence of insulin resistance on endothelial repair in obesity.
... Elevated reactive oxygen species (ROS) levels may attack G triplets in telomeres, leading to DNA cleavage and, consequently, to telomere shortening and cellular dysfunction (20,22). However, while most of the studies reported a significant association with obesity and shorter TL (9,23,24), a few did not observe any correlation (25)(26)(27). In addition, Muezzinler et al. (2014) (24) suggest that there is a biologically plausible inverse association between BMI and leukocyte TL. ...
Introduction:
inflammation and oxidative stress are factors that may play a substantial role in telomere attrition. In line of this, obesity is associated with telomere shortening. Green tea had anti-inflammatory and antioxidant effects and may alter telomere length (TL).
Objectives:
we evaluated the effect of decaffeinated green tea supplementation in obese women on TL.
Methods:
we conducted a cross-sectional interventional study with ten obese (body mass index [BMI] > 40 kg/m²) and eight normal weight (BMI > 18.5 and < 24.9 kg/m²) women (age between 27 and 48 years). The supplementation was carried out with capsules (each contained 450.7 mg of epigallocatechin-3-gallate) during eight weeks. Anthropometric and dietary intake assessment, and blood collection (for biochemical and TL analysis by quantitative PCR) were performed before and after supplementation. Normal weight patients were evaluated at a single moment.
Results:
we observed a significant increase on TL after supplementation (1.57 ± 1.1 to 3.2 ± 2.1 T/Sratio; p < 0.05). Moreover, we found shorter TL in obese patients (day 0) when compared to normal weight individuals (3.2 ± 1.9 T/Sratio; p < 0.05) and an inverse association between TL and BMI, even after age adjustment (beta = -0.527; r² = 0.286; IC = -0.129, -0.009).
Conclusion:
obesity is related to shorter telomeres. Green tea supplementation during eight weeks promotes telomere elongation in obese women.
... Furthermore, cells isolated and stored according to German study yielded better results in terms of proliferative capacity, ability to migrate to the chemoattractant SDF-1 and improvement in blood flow in a mouse model of hindlimb ischaemia. Moreover, there is a substantial individual variability related to quantitative but also qualitative changes of adult bone marrow SCs with age, cardiovascular risk factors and associated comorbidities, decreasing the efficiency of cell therapy particularly in patients who need it the most [31][32][33][34][35] . Studies have shown that young age and a superior number of CD34 + cells were independent predictors for treatment response to cell therapy, demonstrating the importance of patient's cell product [36,37] . ...
In spite of modern treatment, acute myocardial infarction (AMI) still carries significant morbidity and mortality worldwide. Even though standard of care therapy improves symptoms and also long-term prognosis of patients with AMI, it does not solve the critical issue, specifically the permanent damage of cardiomyocytes. As a result, a complex process occurs, namely cardiac remodeling, which leads to alterations in cardiac size, shape and function. This is what has driven the quest for unconventional therapeutic strategies aiming to regenerate the injured cardiac and vascular tissue. One of the latest breakthroughs in this regard is stem cell (SC) therapy. Based on favorable data obtained in experimental studies, therapeutic effectiveness of this innovative therapy has been investigated in clinical settings. Of various cell types used in the clinic, autologous bone marrow derived SCs were the first used to treat an AMI patient, 15 years ago. Since then, we have witnessed an increasing body of data as regards this cutting-edge therapy. Although feasibility and safety of SC transplant have been clearly proved, it’s efficacy is still under dispute. Conducted studies and meta-analysis reported conflicting results, but there is hope for conclusive answer to be provided by the largest ongoing trial designed to demonstrate whether this treatment saves lives. In the meantime, strategies to enhance the SCs regenerative potential have been applied and/or suggested, position papers and recommendations have been published. But what have we learned so far and how can we properly use the knowledge gained? This review will analytically discuss each of the above topics, summarizing the current state of knowledge in the field.
... Recent studies have brought into question quantitative but also qualitative changes of adult SC with old age, cardiovascular risk factors and associated comorbidities (diabetes, arterial hypertension or cardiovascular disease), decreasing the efficiency of cell therapy particularly in patients who need it most [50]. Even though most trials are focused on other types of SCs or progenitors cell (bone marrow SCs [51], adipose-derived stem cells [52][53][54][55], circulating endothelial progenitor cells [56][57][58][59]), there is direct evidence regarding CSCs damage in elderly individuals [60][61][62][63]. ...
Findings in the cardiology field from the last three decades of the 20th century were ruled by the theory that the heart is a post-mitotic organ, incapable to regenerate. Recent studies have brought evidences regarding the existence of some cells residing in the adult heart, having stem properties. These cardiac stem cells (CSCs) govern myocardial homeostasis and repair by differentiating into new cardiomyocytes, smooth muscle cells and vascular endothelial cells and also by releasing proangiogenic and procardiogenic cytokines. Hence, CSC-based therapy seems to be a promising tool for repairing failing hearts. This review presents the current data regarding various subpopulations of CSCs and their regenerative potential revealed by phase I clinical trials; finally, future perspectives for the development of more advanced therapeutic protocols are proposed.
... Among the 63 selected studies, 24 (38%), did not find statistically significant variables showing an association between obesity and TL Obesity Effect of Obesity on Telomeres Mundstock et al. (13,14,(31)(32)(33)38,42,(48)(49)(50)(51)(52)(53)(54)(58)(59)(60)(61)(62)(63)(64)(65)70,73). The remaining 39 studies detected a statistically significant association between obesity and TL, as described in Supporting Information Table S1. ...
Objective:
The main objective of this systematic review is to assess the effects of obesity on telomere length.
Methods:
The following databases were searched: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), LILACS, SPORTdiscus, and Web of Science from inception to August 2014. The search was performed using the following combinations of terms: telomere AND "overweight" OR "obesity" OR "adiposity," without language restriction.
Results:
Sixty-three original studies were included in this systematic review, comprising 119,439 subjects. Thirty-nine studies showed either weak or moderate correlation between obesity and telomere length; however, they showed an important heterogeneity.
Conclusions:
There is a tendency toward demonstrating negative correlation between obesity and telomere length. The selected studies showed weak to moderate correlation for the main search, and there was an important heterogeneity. For this reason, the causal relationship of obesity and telomere length remains open. Additional controlled longitudinal studies are needed to investigate this issue.
... All measures in this study were taken under basal cell conditions, which is not always representative of the in vivo environment. Under resting conditions, these cells are less active and many studies have found that pharmacological challenges such as LPS or PMA stimulate cytokine/growth factor secretion from various cell types (40). We have previously shown that in vivo consumption of a high-fat meal alters the intracellular ROS levels of CACs (26); thus it is our belief that a similar stimulation may also alter the paracrine profile of CACs. ...
We aimed to determine if chronic endurance exercise habits affected redox status and paracrine function of CD34+ and CD34-/CD31+ circulating angiogenic cells (CACs). Subjects were healthy, nonsmoking, men and women aged 18-35 yrs and categorized by chronic physical activity habits. Blood was drawn from each subject for isolation and culture of CD34+ and CD34-/CD31+ CACs. No differences in redox status were found in any group across either cell type. Conditioned media (CM) was generated from the cultured CACs and used in an in vitro HUVEC-based tube assay. CM from CD34+ cells from inactive individuals resulted in tube structures that were 29% shorter in length (P<0.05) and 45% less complex (P<0.05) than the endurance-trained group. CD34-/CD31+ CM from inactive subjects resulted in tube structures that were 26% shorter length (P<0.05) and 42% less complex (P<0.05) than endurance-trained individuals. Proteomics analyses identified S100A8 and S100A9 in the CM. S100A9 levels were 103% higher (P<0.05) and S100A8 was 97% higher in the CD34-/CD31+ CM of inactive subjects compared to their endurance-trained counterparts with no significant differences in either protein in the CM of CD34+ CACs as a function of training status. Recombinant S100A8/A9 treatment at concentrations detected in inactive subjects' CD34-/CD31+ CAC CM also reduced tube formation (P<0.05). These findings are the first, to our knowledge, to demonstrate a differential paracrine role in CD34+ and CD34-/CD31+ CACs on tube formation as a function of chronic physical activity habits and identifies a differential secretion of S100A9 by CD34-/CD31+ CACs due to habitual exercise.
Copyright © 2015, American Journal of Physiology - Heart and Circulatory Physiology.
... 58 Numerous studies showed that the number, proliferation activity, ability for adhesion, migration, and angiogenic properties of EPCs are significantly impaired in patients with CAD 55,59-61 and metabolic disorders including obesity and T2DM. [62][63][64][65] Van Ark et al. 66 demonstrated that in patients with T2DM both EPCs and circulating angiogenic cells levels were reduced and the ratio between EPCs and smooth muscle progenitor cells was disturbed, which may translate into reduced vascular repair capacity, thereby promoting macrovascular disease in T2DM. ...
During recent years different types of adult stem/progenitor cells have been successfully applied for the treatment of many pathologies, including cardiovascular diseases. The regenerative potential of these cells is considered to be due to their high proliferation and differentiation capacities, paracrine activity, and immunologic privilege. However, therapeutic efficacy of the autologous stem/progenitor cells for most clinical applications remains modest, possibly because of the attenuation of their regenerative potential in aged patients with chronic diseases such as cardiovascular diseases and metabolic disorders. In this review we will discuss the risk factors affecting the therapeutic potential of adult stem/progenitor cells as well as the main approaches to mitigating them using the methods of regenerative medicine.
... 111 In healthy men, EPC telomere length was shown to be approximately 20% lower in the older compared with the middle-aged and young men, 112 and leukocyte telomere length is directly associated with circulating EPC levels in young healthy adults. 113 The link between telomere length, EPCs, and senescence is aggravated by the coexistence of risk factor for CVD such as obesity 114 and hypertension, 115,116 typically observed in conditions of insulin resistance. Not all reports are unanimous in linking the senescence of EPCs to telomere length, as Zhang et al 117 showed that tumor necrosis factor (TNF) alpha rather than telomere is implicated in EPC senescence. ...
Although there are different mechanistic theories for aging,1 endothelial dysfunction (ED) is a rather neglected player in the aging process. A maladaptive insulin/IGF-1-like signaling (IIS) has a remarkable importance in proaging mechanisms, and insulin has direct effects on ED.2 Therefore, we assume that the endothelium plays a key role in mediating the aging process in the presence of maladaptive insulin signaling. This latter condition leads to insulin resistance and affects several aspects involved in premature aging, such as body composition, mitochondrial activity, and endocrine function. The present review highlights key mediators and mechanisms responsible for the link between endothelial dysfunction, insulin resistance and aging. In particular, we discuss the sirtuin-1 system, the p66Shc pathway, telomeres, and their interrelationships with endothelial damage and repair.
... It has been previously demonstrated that the reduction and dysfunction of circulating endothelial progenitor cells are strongly associated with the development of atherosclerosis and cardiovascular disease [3,4]. Moreover, increased adiposity is related with a reduced endothelial progenitor cells to release proangiogenic cytokines and resist apoptosis [5]. Also, a previous study has showed that endothelial progenitor cells were inversely correlated with carotid intima-media thicknesse in a middle-aged general population [6]. ...
Endothelial dysfunction is associated with childhood obesity and is closely linked to the amount and function of endothelial progenitor cells. However, it remains unclear whether endothelial progenitor cells increase with after-school exercise in overweight and obese children. The purpose of this study was to investigate the effects of an after-school exercise programme on endothelial cell function in overweight and obese children.
A total of 29 overweight/obese children (12.2 ± 0.1 years) were randomly divided into control (i.e. no after-school exercise, n = 14) and after-school exercise (n = 15) groups. The 12-week after-school exercise intervention consisted of 3 days of combined aerobic and resistance exercise per week. Each 80-minute exercise programme included 10 minutes of warm-up and 10 minutes of cool-down after school. CD34+ (a cell surface marker on hematopoietic stem cells), CD133+ (a cell surface marker on hematopoietic progenitor cells) and CD34+/CD133+ (considered as endothelial progenitor cells) were measured at baseline and after 12 weeks using flow cytometry.
Increased percentages of CD34+, CD133+ and CD34+/CD133+ cells were observed in the after-school exercise group (p = 0.018; p = 0.001; p = 0.002, respectively) compared with the control group. Carotid intima-media thickness decreased after 12 weeks in the after-school exercise group (p = 0.020) compared with the control group.
This study provides preliminary evidence that a combined after-school exercise programme may represent an effective intervention strategy for improving vascular repair and endothelial cell function, leading to improved cardiovascular health in overweight and obese children.
Current Controlled Trials ISRCTN19037201.
... According to previous studies, the alterations in EPCs exist in overweight and obese individuals. Several recent studies show that the numbers of EPCs decreased in overweight and obese populations with an impaired proliferation capacity (34)(35)(36)(37)(38)(39). Heida et al (34) found that the numbers of EPCs in the blood circulation decreased in obese individuals and obese mice; meanwhile, the migration and adhesion capacity of EPCs were impaired. ...
The aim of this study was to study the quantity change of endothelial progenitor cells (EPCs) in obese rats fed a high-fat-diet and to investigate the correlation of EPC numbers with visfatin. The impact of visfatin on the quantity and function of EPCs were further investigated by cell culture methods. Male Wistar rats were fed on either a standard diet (NC group) or a high-fat diet (HF group) for 16 weeks. Serum visfatin, Lee's index and the protein expression of visfatin in viseral adipose tissue (VAT) were determined. Bone marrow EPCs in 2 groups of rats were isolated, cultured and counted. EPCs primarily cultured from control male Wistar rats were treated with different concentrations of visfatin. The quantity, migration and adhesion capacity of EPCs were evaluated after visfatin treatment. Protein expression of nuclear factor-κB (NF-κB) in the nuclei of EPCs was detected. After 16-week feeding, body weight, serum visfatin, Lee's index and visfatin contents in viseral fat were significantly increased in the HF group compared with NC group (P<0.01 or P<0.05). The quantity of EPCs primarily cultured from rats in HF group was lower than that in NC group. The quantity of EPCs was negatively correlated with serum visfatin levels, visceral fat, fasting blood glucose, HOMA-IR, total cholesterol, triglyceride and body weight (P<0.01). In cultured EPCs, visfatin significantly increased the protein expression of NF-κB in EPC nuclei (P<0.01) in a dose-dependent manner. The migration and adhesion capacity were impaired by visfatin treatment (P<0.01). In conclusion, bone marrow-derived EPCs decrease in number and have impaired migration and adhesion function in high-fat-fed obese rats, along with increased serum visfatin and protein contents in VAT. Visfatin may have an impact on the quantity and function of EPCs through the NF-κB pathway.
... Nevertheless, only the increase in CD34 + cells, but not in CD34 + KDR + cells, was positively and discretely correlated with a reduction in the HOMA index after the 12-week treatment in both groups (MeD and MeDE). This finding is partially in accordance with observational studies that have shown that CD34 + cells are the phenotype which relates best to cardiovascular risk factors in MetS patients [4,47]. The present study was not designed; however, to elucidate which were the mechanisms by which exercise could generate an increase in EPCs levels or to understand risk modulation by means of these interventions. ...
A reduction in EPC (endothelial progenitor cell) number could explain the development and progression of atherosclerosis in the MetS (metabolic syndrome). Although much research in recent years has focused on the Mediterranean dietary pattern and the MetS, the effect of this diet with/without moderate-to-high-intensity endurance training on EPCs levels and CrF (cardiorespiratory fitness) remains unclear. In the present study, the objective was to assess the effect of a Mediterranean diet hypocaloric model with and without moderate-to-high-intensity endurance training on EPC number and CrF of MetS patients. Thus 45 MetS patients (50-66 years) were randomized to a 12-week intervention with the hypocaloric MeD (Mediterranean diet) or the MeDE (MeD plus moderate-to-high-intensity endurance training). Training included two weekly supervised sessions [80% MaxHR (maximum heart rate); leg and arm pedalling] and one at-home session (65-75% MaxHR; walking controlled by heart rate monitors). Changes in: (i) EPC number [CD34(+)KDR(+) (kinase insert domain-containing receptor)], (ii) CrF variables and (iii) MetS components and IRH (ischaemic reactive hyperaemia) were determined at the end of the study. A total of 40 subjects completed all 12 weeks of the study, with 20 in each group. The MeDE led to a greater increase in EPC numbers and CrF than did the MeD intervention (P ≤ 0.001). In addition, a positive correlation was observed between the increase in EPCs and fitness in the MeDE group (r=0.72; r(2)=0.52; P ≤ 0.001). Body weight loss, insulin sensitivity, TAGs (triacylglycerols) and blood pressure showed a greater decrease in the MeDE than MeD groups. Furthermore, IRH was only improved after the MeDE intervention. In conclusion, compliance with moderate-to-high-intensity endurance training enhances the positive effects of a model of MeD on the regenerative capacity of endothelium and on the fitness of MetS patients.
... EPC migratory capacity was measured using a modified Boyden chamber. [12] Non-adherent cells (4 × 10 5 ) were resuspended in serum-free culture medium (Medium 199, GIBCO) and loaded in the upper compartment of a 24well modified Boyden chamber coated with fibronectin (FluoroBlok, BD Biosciences). The upper chamber was placed in the lower chamber containing culture medium supplemented with vascular endothelial growth factor (2 ng/ml) and incubated for 22 h at 37°C. ...
Chronic short sleep duration has been linked to endothelial dysfunction and increased risk of cardiovascular disease. Circulating endothelial progenitor cells (EPCs) are vital to endogenous vascular repair processes and cardiovascular health. We tested the hypothesis that habitual short sleep duration is associated with impairment in EPC number and function. Cells with phenotypic EPC characteristics were isolated from 37 healthy, sedentary adults: 20 with normal sleep duration (13M/7F; age: 59±1 years; sleep duration: 7.7±0.1 h/night) and 17 with short sleep duration (9M/8F; 56±2 years; 6.0±0.2 h/night). EPC number was assessed by flow cytometric analysis of the percentage of peripheral blood mononuclear cells negative for CD45 and positive for CD34, VEGFR-2, and CD133 antigens. EPC colony-forming capacity was determined by colony-forming unit (CFU) assay; migration by Boyden chamber; and intracellular caspase-3 concentrations by immunoassay. There were no significant differences between groups in EPC number (0.001±0.0004 vs. 0.001±0.0003 %), colony-forming capacity (6.1±1.5 vs. 5.4±1.7 CFUs), or migration to VEGF (1410.1±151.2 vs. 1334.3±111.1 AU). Furthermore, there were no group differences in basal and staurosporine-stimulated intracellular concentrations of active caspase-3 (0.3±0.03 vs. 0.5±0.1 ng/mL; and 2.9±0.4 vs. 2.7±0.3 ng/mL), a marker of apoptotic susceptibility. Taken together, these data indicate that short sleep duration is not associated with EPC dysfunction in healthy adults. Numerical and functional impairment in circulating EPCs may not contribute to the increased cardiovascular risk with habitual short sleep duration.
... Additionally, functional impairment of EPCs correlates with coronary artery disease risk [21] . Various mechanisms have been implicated in EPC/CAC dysfunction in these conditions, including reactive oxygen species, telomere shortening/senescence and cytokines such as TNF222324. ...
Patients with systemic lupus erythematosus have up to a 50-fold increased risk of developing atherosclerotic cardiovascular disease. Recent advances in the etiology of vascular damage in this disease stress the interplay of lupus-specific inflammatory factors with traditional cardiac risk factors, leading to increased endothelial damage. This review analyzes the putative role that immune dysregulation and lupus-specific factors may play in the pathogenesis of premature vascular damage in this disease. The potential role of various cytokines, in particular type I interferons, in the development of accelerated atherosclerosis is examined. Potential therapeutic targets are discussed.
... Both circulating EPC numbers and EPC colony-forming capacity were found to be reduced in obese persons [69]. Focussing on the functional properties of EPCs in this overweight/obese population, the authors additionally demonstrated that EPCs from the overweight/obese study subjects produced less pro-angiogenic growth factors, such as VEGF and G-CSF, and displayed more cell apoptosis [70]. Another study in a morbidly obese study population [71] showed a reduction in several circulating progenitor cell populations and a decrease in EPC colony-forming capacity. ...
For more than a decade, endothelial progenitor cells (EPCs) have been implicated in cardiovascular homeostasis. EPCs are believed to reside within the bone marrow in close contact with surrounding stromal cells, and, under stimulation of pro-inflammatory cytokines, EPCs are mobilized out of the bone marrow. Hereafter circulating EPCs home to peripheral tissues, undergoing further proliferation and differentiation. Under certain pathophysiologic conditions this process seems to be blunted, resulting in a reduced capacity of EPCs to engage in vasculogenesis at sites of endothelial injury or tissue ischemia. In this review, we focus on the effects of traditional cardiovascular risk factors on EPC biology and we explore whether pharmacological, dietary and lifestyle interventions can favorably restore EPC mobilization, differentiation, homing and angiogenic properties. Because the PI3K/Akt/eNOS pathway plays a pivotal role in the process of EPC mobilization, migration and homing, we specifically emphasize the involvement of PI3K, Akt and eNOS in EPC biology under these different (patho)physiologic conditions. (Pre)clinically used drugs or lifestyle interventions that have been shown to ameliorate EPC biology are reviewed. These treatment strategies remain attractive targets to restore the regenerative capacity of EPCs in cardiovascular diseases.
Obesity, which predisposes to persistant metabolic disorders such as diabetes, dyslipidemia, and hypertension, has been reported to correlate with accelerated biological aging with shortened somatic telomere length. In these disease states, production of peroxidative biochemical compounds is systemically promoted, which is believed to be the major cause of telomere depletion. Therefore, obesity is an underlying condition that accelerates biological aging due to telomere depletion. Obesity itself also contributes to mild telomere shortening due to somatic cell peroxidation. In addition, obesity may be associated with subtelomeric demethylation, a biomarker for accelerated telomere shortening. Calorie restriction (CR) is now the most powerful and efficient intervention and involves the administration of a well-balanced and nutrient-dense diet that reduces calorie intake. This study was to investigate the impact of CR on cardiac senescence in an animal model of diabetes and examine the signal transduction mechanisms for changes in cell survival as well as cardiac function. Male 8-week-old Otsuka Long-Evans Tokushima fatty (OLETF) diabetic rats were divided into 2 groups: a group fed ad libitum (AL), and a group fed with CR (30% energy reduction). At 40 weeks of age, the telomere length was not altered in experimental rats with or without CR, however, telomerase activity in both strains of CR rats was significantly elevated. Obesity, as well as accelerated aging, can be considered a premetabolic disease state. Preventing obesity and managing your diet to keep your body mass index within normal limits are important steps in anti-aging.
Obesity drives an excessive triglycerides accumulation in adipose tissue, which incites immune cell infiltration, causing fibrosis and inflammation, causing local hypoxia in adipocytes, and ultimately insulin resistance. The extracellular matrix (ECM) complex network of proteins and proteoglycans that offer a scaffold for cells controlling differentiation, migration, repair, survival, and development, and ECM remodeling is required for healthy adipose tissue expansion. To understand the molecular mechanism of this process is a challenge in order to prevent or treat metabolic diseases. This chapter describes the different ECM components and their function related to adipose tissue and their contribution to restore or maintain insulin sensitivity and the whole body metabolism.
Nowadays, respiratory infections are one of the main causes of death worldwide. It was always thought that the respiratory tract was devoid of its microbiota, but it was a few years ago when this changed. It has not only been described but also the pulmonary microbial community is altered in the context of various respiratory disorders. Despite the lack of knowledge about its role in health and disease, there is evidence indicating that the use of probiotics may have beneficial effects during respiratory disorders since they can modulate the immune system both directly and indirectly.
Telomere length (TL) is a hallmark of cellular aging and is associated with chronic diseases development. The vascular endothelial growth factor A (VEGF-A), a potent angiogenesis factor, is implicated in the pathophysiology of many chronic diseases. The aim of the present study was to investigate the associations between VEGF-A and TL.
TL in leukocytes (LTL) and skeletal muscle (MTL) were measured, 10 VEGF-related polymorphisms genotyped, and VEGF-A plasma concentrations determined in 402 individuals from the TELARTA cohort. LTL/MTL ratio was calculated as an estimate of lifelong TL attrition. Associations between VEGF-A variants and levels, and TL parameters were investigated.
We identified one significant association between the minor allele (T) of rs6993770 variant and LTL/MTL ratio (P=0.001143, β=0.0148, SE=0.004516). The rs6993770 is an intronic variant of the ZFPM2 gene, which is involved in haematopoiesis and the identified association with increased telomere attrition could be due to increased haematopoiesis. No significant epistatic interaction was identified, and no association was found between levels of VEGF-A and any of assessed phenotypes.
We identified a potential common genetic regulation between VEGF-A and telomere length attrition that could be explained by mechanisms of increased hematopoiesis and production of platelets. VEGF-A and TL could play an important role in personalized medicine of chronic diseases and identification of molecular links between them can promote the understanding of their complex implications.
Objective
Obesity is associated with telomere attrition – a marker of cellular and biological aging. The US has the highest proportion of obesity and is comprised of a racially/ethnic diverse population. Little is known about the relationship between obesity and telomere attrition according to race/ethnicity in the US. Our objective is to examine the differential association.
Design and setting
The effect of body mass index (BMI), % total body fat (TBF) and waist circumference (WC) on leukocyte telomere length (LTL) were examined as adiposity measures according to race/ethnicity and sex specific race/ethnicity using separate adjusted linear regressions on a sample of 4,919 respondents aged 20-84 years from cross-sectional 1999-2002 data using the US National Health and Nutrition Examination Survey. Mediation analyses assessed health behaviors associated with relationship between adiposity measures and LTL.
Main outcome measure
LTL
Results
African Americans (AA) experienced a 28% and 11% decrease in LTL associated with increasing BMI and WC, ( p =.02 and .03) respectively. Mexican Americans (MA) experienced a 33% decrease in LTL associated with increasing %TBF ( p =.04). Whites experienced a 19%, 23%, and .08% decrease in LTL associated with increasing BMI, %TBF, and WC, ( p =.05, .003, .02) respectively. White men experienced a 26% decrease in LTL due to increasing BMI ( p =.05). AA women experienced a 41%, 44%, and 16% decrease in LTL due to increasing BMI, %TBF, and WC, respectively ( p =.007, .02, .04). White women experienced a 29% decrease in LTL associated with increasing %TBF ( p =.006). Selected health behaviors were associated with the relationship between adiposity measures and LTL.
Conclusion
Overall, AA and Whites have worse cellular and biological aging related to collective adiposity measures. According to sex, AA women experienced more deleterious cellular and biological aging. Findings suggest tailored interventions to improve adverse behaviors that contribute to obesity may improve telomere attrition in US adults.
Objective:
Little is known about the relationship between adiposity and telomere length in the United States population. The objective of our research was to examine this relationship in a representative, socioeconomically and sex-specific, diverse racial/ethnic population in the United States.
Methods:
Body mass index (BMI), % total body fat (TBF) and waist circumference (WC) with leukocyte telomere length (LTL) were examined according to sex-specific race/ethnicity using separate adjusted multivariate linear regressions on a sample of 4,919 respondents aged 20-84 years from the National Health and Nutrition Examination Survey's 1999-2002 data.
Results:
LTL was shortened .41%, .44%, and .16% in African American (AA) women and was associated with increasing BMI, %TBF, and WC, (β:-.0041, 95%CI: -.0070, -.0012; P=.007; β:-.0044, 95% CI: -.0081, -.0007; P=.02; β:-.0016, 95%CI: -.0031, -.0001; P=.04, respectively). LTL was shortened .29% in White women and was associated with increasing %TBF (β:-.0029, 95%CI: -.0048, -.0009; P=.006). There were no associations among AA men, White men or Mexican American men and women.
Conclusions:
LTL is associated with an obesity phenotype in AA women. Tailored intervention is needed to ameliorate the burden of excess adiposity and subsequent cellular aging.
Bone marrow-derived early outgrowth cells play an important role in endothelial repair. In vitro isolation techniques have identified two distinct morphological early outgrowth cell populations, but it is still unknown whether they present some functional phenotypic differences. Accordingly, the aim of the present study was to determine whether there are phenotypic differences in cellular function between two putative early outgrowth cells in culture. Peripheral blood samples were collected from 18 healthy adults. Thereafter, mononuclear cells were isolated by Ficoll density-gradient centrifugation and plated on 6-well plates coated with human fibronectin. After 2 and 7 days, respectively, non-adherent cells (NAC) and adherent cells (AC) underwent functional assays in order to measure the migratory capacity (Boyden chamber), angiogenic growth factor release (ELISA) and apoptosis (TUNEL). Migration to both VEGF (517 ± 74 vs. 273 ± 74 AU) and SDF-1 (517 ± 68 vs. 232 ± 68 AU) were approximately twofold higher (P < 0.05) in the NAC when compared to AC. Release of angiogenic factors, granulocyte colony-stimulating and hepatocyte growth factor, were not different between cell types. Apoptotic response to staurosporine was significantly lower in NAC (20 ± 32 vs. 125 ± 32%). In summary, NAC and AC demonstrated functional phenotypic differences in migratory capacity and apoptotic susceptibility, which makes it difficult to compare these two early outgrowth cell populations in literature.
Background
Several studies have linked vascular endothelial growth factors (VEGFs) with metabolic syndrome or its components. However, there has been no systematic appraisal of the findings of these studies to date. The current systematic review and meta-analysis was conducted to explore this association.
Methods
PubMed, EMBASE, the Cochrane library, and clinical trials registries were used to retrieve peer-reviewed clinical studies that had evaluated the association of VEGFs with metabolic syndrome or its components without applying language and date restrictions. The final search was performed on 29 September 2017.
Results
We included 32 studies in this systematic review and meta-analysis, of which 16 studies (19 study arms) were included in the meta-analysis and remaining studies were qualitatively assessed. Overall, VEGF-A, VEGF-B and VEGF-C were strongly associated with metabolic syndrome or its components. The components of metabolic syndrome varied in their association. Obesity was not correlated with increased VEGF-A expression (p = 0.12), whereas VEGF-B and VEGF-C expression was significantly higher in those with obesity. In contrast, hyperglycemia in type 1 diabetes was strongly associated with increased VEGF-A levels (p < 0.00001), as was type 2 diabetes (p = 0.0006). The studies included in the qualitative analysis similarly showed an increase in VEGF family expression in people with metabolic syndrome, and with its components.
Conclusion
The increased concentrations of vascular endothelial growth factors are variably associated with metabolic syndrome or its components. Each VEGF protein has a unique set of associations with the disease state.
The repair and regeneration of adult tissues is accomplished through the existence and function of stem or progenitor cell populations. With regards to vascular repair, this is accomplished through the use of heterogeneous populations of proangiogenic cells, often called the endothelial progenitor cells (EPCs). In response to hypoxic or inflammatory signals, EPCs are mobilized from storage niches such as the bone marrow, home to site of vascular damage and participate in repair through terminal differentiation or paracrine effects. While the existence of these endothelial reparative cells has been recognized for almost 20 years, an accurate phenotypic description of these cells still remains controversial and complex analytical strategies are required for their identification and functional analysis. Multiple animal and human studies have demonstrated the physiological importance of EPCs, and evidence suggests a paucity of these cells or their dysfunction is correlated with poor vascular health and an increased risk of developing or exacerbating cardiovascular disease. Moreover, the levels and functionality of these cells are particularly sensitive to toxicological exposures and external influences, defining a mechanistic connection between such stimuli and resulting pathology.
Recent advances in stem cell research have generated excitement for the use of cardiac stem cells (CSCs) as a viable cell therapy option for myocardial repair. This chapter reviews evidence for resident CSCs and examines the capacity of transplanted ex vivo proliferated CSCs to improve heart function after cardiac damage. Reflection upon recent preclinical and phase I studies of current first-generation CSC products will prompt a deeper understanding of challenges (and opportunities) confronting the next generation of this remarkable therapy.
To investigate the relationship between the changes in the number and function of the late endothelial progenitor cells (EPC) in peripheral blood and the carotid artery stenosis. 60 cases were selected and were divided into the carotid artery stenosis group of 40 cases (mild stenosis in 20 cases, moderate/severe stenosis in 20 cases), normal control group of 20 cases with the global cerebral angiography. Extracted the blood of femoral artery from the patients during the global cerebral angiography, mononuclear cells were isolated from peripheral blood by density-gradient centrifugation and were cultured to 21 days when they were identified as late endothelial progenitor cells, counted the colony numbers of late EPC. Then the proliferation, migration and adherentce ability of late EPC were determined by the MTT assay, modified Boyden and the HFN culturing plates. The amount of the late EPC colonies(34.30 ± 4.90, 25.38 ± 6.33) were significantly reduced in the patients with carotid artery stenosis compared with the control group (46.00 ± 5.64) (P < 0.05); the function of proliferation, migration, adhesion of the late EPC in patiens with cerebral artery stenosis were significantly lower (P < 0.05), the number and function of late EPC decreased with the worsening of vascular stenosis (P < 0.05). The number of EPC in peripheral blood of patients with the carotid artery stenosis decreased, the function was impaired, and number and function changes of late EPC were negatively correlated with the degree of carotid artery stenosis.
Loss of telomeric DNA during cell proliferation may play a role in ageing and cancer. Since telomeres permit complete replication of eukaryotic chromosomes and protect their ends from recombination, we have measured telomere length, telomerase activity and chromosome rearrangements in human cells before and after transformation with SV40 or Ad5. In all mortal populations, telomeres shortened by approximately 65 bp/generation during the lifespan of the cultures. When transformed cells reached crisis, the length of the telomeric TTAGGG repeats was only approximately 1.5 kbp and many dicentric chromosomes were observed. In immortal cells, telomere length and frequency of dicentric chromosomes stabilized after crisis. Telomerase activity was not detectable in control or extended lifespan populations but was present in immortal populations. These results suggest that chromosomes with short (TTAGGG)n tracts are recombinogenic, critically shortened telomeres may be incompatible with cell proliferation and stabilization of telomere length by telomerase may be required for immortalization.
Background— Endothelial progenitor cells (EPCs) have been isolated from peripheral blood and can enhance angiogenesis after infusion into host animals. It is not known whether the proangiogenic effects are a result of such events as endothelial differentiation and subsequent proliferation of EPCs or secondary to secretion of angiogenic growth factors.
Methods and Results— Human EPCs were isolated as previously described, and their phenotypes were confirmed by uptake of acetylated LDL and binding of ulex-lectin. EPC proliferation and surface marker expression were analyzed by flow cytometry, and conditioned medium was assayed for growth factors. The majority of EPCs expressed monocyte/macrophage markers such as CD14 (95.7±0.3%), Mac-1 (57.6±13.5%), and CD11c (90.8±4.9%). A much lower percentage of cells expressed the specific endothelial marker VE-cadherin (5.2±0.7%) or stem/progenitor-cell markers AC133 (0.16±0.05%) and c-kit (1.3±0.7%). Compared with circulating monocytes, cultured EPCs showed upregulation of monocyte activation and macrophage differentiation markers. EPCs did not demonstrate any significant proliferation but did secrete the angiogenic growth factors vascular endothelial growth factor, hepatocyte growth factor, granulocyte colony–stimulating factor, and granulocyte-macrophage colony–stimulating factor.
Conclusions— Our findings suggest that acetylated LDL(+)ulex-lectin(+) cells, commonly referred to as EPCs, do not proliferate but release potent proangiogenic growth factors. The majority of acetylated LDL(+)ulex-lectin(+) cells are derived from monocyte/macrophages. The findings of low proliferation and endothelial differentiation suggest that their angiogenic effects are most likely mediated by growth factor secretion. These findings may allow for development of novel angiogenic therapies relying on secreted growth factors or on recruitment of endogenous monocytes/macrophages to sites of ischemia.
To investigate whether adiposity influences endothelial progenitor cell (EPC) number and colony-forming capacity.
Cross-sectional study of normal weight, overweight and obese adult humans.
Sixty-seven sedentary adults (aged 45-65 years): 25 normal weight (body mass index (BMI) <or=25 kg/m(2); 12 males/13 females); 18 overweight (BMI=25-29.9 kg/m(2); 12 males/6 females); and 24 obese (BMI >or=30 kg/m(2); 18 males/6 females). All participants were non-smokers and free of overt cardiometabolic disease.
Peripheral blood samples were collected and circulating EPC number was assessed by flow cytometry. Putative EPCs were defined as CD45(-)/CD34(+)/VEGFR-2(+)/CD133(+) or CD45(-)/CD34(+) cells. EPC colony-forming capacity was measured in vitro using a colony-forming unit (CFU) assay.
Number of circulating putative EPCs (either CD45(-)/CD34(+)/VEGFR-2(+)/CD133(+) or CD45(-)/CD34(+) cells) was lower (P<0.05) in obese (0.0007+/-0.0001%; 0.050+/-0.006%) compared with overweight (0.0016+/-0.0004%; 0.089+/-0.019%) and normal weight (0.0015+/-0.0003%; 0.082+/-0.008%) adults. There were no differences in EPC number between the overweight and normal weight groups. EPC colony formation was significantly less in the obese (6+/-1) and overweight (4+/-1) compared with normal weight (9+/-2) adults.
These results indicate that: (1) the number of circulating EPCs is lower in obese compared with overweight and normal weight adults; and (2) EPC colony-forming capacity is blunted in overweight and obese adults compared with normal weight adults. Impairments in EPC number and function may contribute to adiposity-related cardiovascular risk.
Telomere length declines with age in mature endothelial cells and is thought to contribute to endothelial dysfunction and atherogenesis. Bone marrow-derived circulating endothelial progenitor cells (EPCs) are critical to vascular health as they contribute to both reendothelialization and neovascularization. We tested the hypothesis that EPC telomere length decreases with age in healthy adult humans.
Peripheral blood samples were collected from 40 healthy, non-obese, sedentary men: 12 young (age 21-34 years), 12 middle-aged (43-55 years) and 16 older (57-68 years). Putative EPCs were isolated from peripheral blood mononuclear cells and telomere length was determined using genomic DNA preparation and Southern hybridization techniques.
EPC telomere length (base pairs) was approximately 20% (p=0.01) lower in the older (8492+523 bp) compared to the middle-aged (10,565+572 bp) and young (10,205+501 bp) men. Of note, there was no difference in EPC telomere length between the middle-aged and young men.
These results demonstrate that EPC telomere length declines with age in healthy, sedentary men. Interestingly, telomere length was well preserved in the middle-aged compared to young men, suggesting that EPC telomere shortening occurs after the age of 55 years.
Loss of telomeric DNA during cell proliferation may play a role in ageing and cancer. Since telomeres permit complete replication of eukaryotic chromosomes and protect their ends from recombination, we have measured telomere length, telomerase activity and chromosome rearrangements in human cells before and after transformation with SV40 or Ad5. In all mortal populations, telomeres shortened by approximately 65 bp/generation during the lifespan of the cultures. When transformed cells reached crisis, the length of the telomeric TTAGGG repeats was only approximately 1.5 kbp and many dicentric chromosomes were observed. In immortal cells, telomere length and frequency of dicentric chromosomes stabilized after crisis. Telomerase activity was not detectable in control or extended lifespan populations but was present in immortal populations. These results suggest that chromosomes with short (TTAGGG)n tracts are recombinogenic, critically shortened telomeres may be incompatible with cell proliferation and stabilization of telomere length by telomerase may be required for immortalization.
Putative endothelial cell (EC) progenitors or angioblasts were isolated from human peripheral blood by magnetic bead selection on the basis of cell surface antigen expression. In vitro, these cells differentiated into ECs. In animal models of ischemia, heterologous, homologous, and autologous EC progenitors incorporated into sites of active angiogenesis. These findings suggest that EC progenitors may be useful for augmenting collateral vessel growth to ischemic tissues (therapeutic angiogenesis) and for delivering anti- or pro-angiogenic agents, respectively, to sites of pathologic or utilitarian angiogenesis.
Endothelial progenitor cells (EPCs) have been isolated from circulating mononuclear cells in human peripheral blood and shown to be incorporated into foci of neovascularization, consistent with postnatal vasculogenesis. We determined whether endogenous stimuli (tissue ischemia) and exogenous cytokine therapy (granulocyte macrophage-colony stimulating factor, GM-CSF) mobilize EPCs and thereby contribute to neovascularization of ischemic tissues. The development of regional ischemia in both mice and rabbits increased the frequency of circulating EPCs. In mice, the effect of ischemia-induced EPC mobilization was demonstrated by enhanced ocular neovascularization after cornea micropocket surgery in mice with hindlimb ischemia compared with that in non-ischemic control mice. In rabbits with hindlimb ischemia, circulating EPCs were further augmented after pretreatment with GM-CSF, with a corresponding improvement in hindlimb neovascularization. There was direct evidence that EPCs that contributed to enhanced corneal neovascularization were specifically mobilized from the bone marrow in response to ischemia and GM-CSF in mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase transcriptionally regulated by the endothelial cell-specific Tie-2 promoter. These findings indicate that circulating EPCs are mobilized endogenously in response to tissue ischemia or exogenously by cytokine therapy and thereby augment neovascularization of ischemic tissues.
Angiostatin, a product of the proteolytic cleavage of plasminogen, possesses potent antitumor and antiangiogenic properties in vivo. Studies with cultured endothelial cells suggest that under certain conditions, angiostatin inhibits the migration and proliferation of these cells or, alternatively, increases their rate of apoptosis. In general, the effects of angiostatin have been considerably less potent in vitro than in vivo. One potential explanation for this disparity is that the in vivo target of angiostatin is not the mature endothelial cell. Recently, evidence has accumulated to show that circulating endothelial progenitor cells (EPCs) contribute to neovascularization. In this study, we have isolated EPCs from human subjects and demonstrated that, in contrast to that of mature endothelial cells, the growth of EPCs is exquisitely sensitive to angiostatin. These results suggest that angiostatin and related compounds may exert their biological effects by inhibiting the contribution of EPCs to angiogenesis and not by altering the growth of mature endothelial cells.
Cardiovascular risk factors contribute to atherogenesis by inducing endothelial-cell injury and dysfunction. We hypothesized that endothelial progenitor cells derived from bone marrow have a role in ongoing endothelial repair and that impaired mobilization or depletion of these cells contributes to endothelial dysfunction and cardiovascular disease progression.
We measured the number of colony-forming units of endothelial progenitor cells in peripheral-blood samples from 45 men (mean [+/-SE] age, 50+/-2 years). The subjects had various degrees of cardiovascular risk but no history of cardiovascular disease. Endothelium-dependent and endothelium-independent function was assessed by high-resolution ultrasonography of the brachial artery.
We observed a strong correlation between the number of circulating endothelial progenitor cells and the subjects' combined Framingham risk factor score (r=-0.47, P=0.001). Measurement of flow-mediated brachial-artery reactivity also revealed a significant relation between endothelial function and the number of progenitor cells (r=0.59, P<0.001). Indeed, the levels of circulating endothelial progenitor cells were a better predictor of vascular reactivity than was the presence or absence of conventional risk factors. In addition, endothelial progenitor cells from subjects at high risk for cardiovascular events had higher rates of in vitro senescence than cells from subjects at low risk.
In healthy men, levels of endothelial progenitor cells may be a surrogate biologic marker for vascular function and cumulative cardiovascular risk. These findings suggest that endothelial injury in the absence of sufficient circulating progenitor cells may affect the progression of cardiovascular disease.
Endothelial progenitor cells (EPCs) have been isolated from peripheral blood and can enhance angiogenesis after infusion into host animals. It is not known whether the proangiogenic effects are a result of such events as endothelial differentiation and subsequent proliferation of EPCs or secondary to secretion of angiogenic growth factors.
Human EPCs were isolated as previously described, and their phenotypes were confirmed by uptake of acetylated LDL and binding of ulex-lectin. EPC proliferation and surface marker expression were analyzed by flow cytometry, and conditioned medium was assayed for growth factors. The majority of EPCs expressed monocyte/macrophage markers such as CD14 (95.7+/-0.3%), Mac-1 (57.6+/-13.5%), and CD11c (90.8+/-4.9%). A much lower percentage of cells expressed the specific endothelial marker VE-cadherin (5.2+/-0.7%) or stem/progenitor-cell markers AC133 (0.16+/-0.05%) and c-kit (1.3+/-0.7%). Compared with circulating monocytes, cultured EPCs showed upregulation of monocyte activation and macrophage differentiation markers. EPCs did not demonstrate any significant proliferation but did secrete the angiogenic growth factors vascular endothelial growth factor, hepatocyte growth factor, granulocyte colony-stimulating factor, and granulocyte-macrophage colony-stimulating factor.
Our findings suggest that acetylated LDL(+)ulex-lectin(+) cells, commonly referred to as EPCs, do not proliferate but release potent proangiogenic growth factors. The majority of acetylated LDL(+)ulex-lectin(+) cells are derived from monocyte/macrophages. The findings of low proliferation and endothelial differentiation suggest that their angiogenic effects are most likely mediated by growth factor secretion. These findings may allow for development of novel angiogenic therapies relying on secreted growth factors or on recruitment of endogenous monocytes/macrophages to sites of ischemia.
Chronic myocardial ischaemia due to coronary artery stenosis or occlusion has been shown to increase the growth of coronary collateral circulation. Collateralization leads to increased oxygen delivery to the area at risk and hence may reduce ischaemia, prevent infarction and preserve contractile function. However, there is considerable variation among patient subsets in terms of the presence or degree of collateralization. We aimed to evaluate the relationship between obesity and coronary collateral development in patients with ischaemic heart disease.
In all, 215 patients (mean age, 57.8+/-8.9 y) with body mass index (BMI)> or =30 kg/m(2) were enrolled into our study. A total of 90 age- and sex-matched patients (mean age, 58.7+/-10 y) with BMI<25 kg/m(2) and significant coronary artery disease were selected as a control group. The mean age and distribution of risk factors for coronary heart disease were not significantly different between two groups other than poorer HDL cholesterol and triglyceride profile in obese patients. The mean BMI was significantly higher in the patient group (33.3+/-2.4 vs 22.8+/-1.7, P<0.001). The mean number of diseased vessels and maximum lesion severity were not significantly different between the two groups. The mean Rentrop collateral score of the patient group was significantly worse than the control group (1.08+/-0.68 vs 2.10+/-0.72, P<0.001).
Our findings suggest that collateral vessel development is poorer in obese patients (defined as BMI> or =30 kg/m(2)) with ischemic heart disease compared to normal range BMI, and the risk of having poor collateral vessel development is significantly increased. However, this might be reflecting the cluster of risk factors, associated with metabolic syndrome, in which insulin resistance plays a major role.
Endothelial release of tissue-type plasminogen activator (t-PA) regulates fibrinolysis and is considered to be a primary endogenous defense mechanism against thrombosis. Adiposity is associated with an increased risk of atherothrombotic events. We determined the influence of overweight and obesity on the capacity of the vascular endothelium to release t-PA and the effects of regular aerobic exercise on endothelial t-PA release in previously sedentary overweight and obese adults. First, we studied 66 sedentary adults: 28 normal-weight (BMI < 25 kg/m2); 22 overweight (BMI > or = 25 and < 30 kg/m2); and 16 obese (BMI > or = 30 kg/m2). Net endothelial t-PA release was determined in vivo in response to intrabrachial infusions of bradykinin (BK) and sodium nitroprusside. Second, we studied 17 overweight and obese adults who completed a 3-mo aerobic exercise intervention. Net release of t-PA in response to BK was approximately 45% lower (P < 0.01) in overweight (from 0.1 +/- 0.4 to 41.7 +/- 4.9 ng x 100 ml tissue(-1) x min(-1)) and obese (-0.1 +/- 0.6 to 47.7 +/- 5.2 ng x 100 ml tissue(-1) x min(-1)) compared with normal-weight (0.1 +/- 0.8 to 77.5 +/- 6.7 ng x 100 ml tissue(-1) x min(-1)) adults. There was no difference in t-PA release between the overweight and obese groups. Exercise training significantly increased t-PA release capacity in overweight and obese adults (from -0.3 +/- 0.5 to 37.1 +/- 4.9 ng x 100 ml tissue(-1) x min(-1) before training vs. 1.0 +/- 0.9 to 65.4 +/- 6.3 ng x 100 ml tissue(-1) x min(-1) after training) to levels comparable with those of their normal-weight peers. These results indicate that overweight and obesity are associated with profound endothelial fibrinolytic dysfunction. Importantly, however, regular aerobic exercise can increase the capacity of the endothelium to release t-PA in this at-risk population.
Obesity and smoking are important risk factors for many age-related diseases. Both are states of heightened oxidative stress, which increases the rate of telomere erosion per replication, and inflammation, which enhances white blood cell turnover. Together, these processes might accelerate telomere erosion with age. We therefore tested the hypothesis that increased body mass and smoking are associated with shortened telomere length in white blood cells. We investigated 1122 white women aged 18-76 years and found that telomere length decreased steadily with age at a mean rate of 27 bp per year. Telomeres of obese women were 240 bp shorter than those of lean women (p=0.026). A dose-dependent relation with smoking was recorded (p=0.017), and each pack-year smoked was equivalent to an additional 5 bp of telomere length lost (18%) compared with the rate in the overall cohort. Our results emphasise the pro-ageing effects of obesity and cigarette smoking.
The limited vessel-forming capacity of infused endothelial progenitor cells (EPCs) into patients with cardiovascular dysfunction may be related to a misunderstanding of the biologic potential of the cells. EPCs are generally identified by cell surface antigen expression or counting in a commercially available kit that identifies "endothelial cell colony-forming units" (CFU-ECs). However, the origin, proliferative potential, and differentiation capacity of CFU-ECs is controversial. In contrast, other EPCs with blood vessel-forming ability, termed endothelial colony-forming cells (ECFCs), have been isolated from human peripheral blood. We compared the function of CFU-ECs and ECFCs and determined that CFU-ECs are derived from the hematopoietic system using progenitor assays, and analysis of donor cells from polycythemia vera patients harboring a Janus kinase 2 V617F mutation in hematopoietic stem cell clones. Further, CFU-ECs possess myeloid progenitor cell activity, differentiate into phagocytic macrophages, and fail to form perfused vessels in vivo. In contrast, ECFCs are clonally distinct from CFU-ECs, display robust proliferative potential, and form perfused vessels in vivo. Thus, these studies establish that CFU-ECs are not EPCs and the role of these cells in angiogenesis must be re-examined prior to further clinical trials, whereas ECFCs may serve as a potential therapy for vascular regeneration.
Numerical and functional impairment of circulating endothelial progenitor cells (EPCs) is thought to contribute to vascular aging and the associated increase in cardiovascular risk. We tested the following hypotheses: 1) EPC clonogenic and migratory capacity decrease progressively with age in healthy, sedentary adult men; and 2) regular aerobic exercise will improve EPC clonogenic and migratory capacity in previously sedentary middle-aged and older men. Peripheral blood samples were collected from 46 healthy sedentary men: 10 young (26 +/- 1 yr), 15 middle-aged (47 +/- 1 yr), and 21 older (63 +/- 1 yr). Mononuclear cells were isolated and preplated for 2 days, and nonadherent cells were further cultured for 7 days to determine EPC colony-forming units. Migratory activity of EPCs was determined using a modified Boyden chamber. Ten sedentary middle-aged and older men (59 +/- 3 yr) were studied before and after a 3-mo aerobic exercise intervention. The number of EPC colony-forming units was approximately 75% lower (P < 0.01) in middle-aged (12 +/- 3) and older (8 +/- 2) compared with young (40 +/- 7) men. There was no difference in colony count between middle-aged and older men. EPC migration (fluorescent units) was significantly reduced in older (453 +/- 72) compared with young (813 +/- 114) and middle-aged (760 +/- 114) men. The exercise intervention increased (P < 0.05) both EPC colony-forming units (10 +/- 3 to 22 +/- 5) and migratory activity (683 +/- 96 to 1,022 +/- 123) in previously sedentary middle-aged and older men. These results provide further evidence that aging adversely affects EPC function. Regular aerobic-endurance exercise, however, is an effective lifestyle intervention strategy for improving EPC clonogenic and migratory capacity in middle-aged and older healthy men.
The investigators tested the hypothesis that circulating endothelial progenitor cells might aid endothelial repair on an ongoing basis by forming a cellular "patch" at sites of denuding injury. In addition, they might provide a reservoir of cells with which to replace dysfunctional endothelium. Colony-forming units of endothelial progenitor cells were estimated in peripheral blood samples from 45 men, whose mean age was 50 years, with varying cardiovascular risk but no history of cardiovascular disease. The samples were plated onto fibronectin-coated dishes, a process known to isolate cells possessing many features of endothelial cells. Endothelium-dependent and endothelium-independent function were evaluated by high-resolution ultrasonography of the brachial artery. Numbers of endothelial progenitor cell colony-forming units were significantly reduced in subjects having elevated serum cholesterol, hypertension, or diabetes. Cell numbers correlated inversely with age, but not to a significant degree. Age-adjusted analyses showed hypercholesterolemia to be the only significant risk factor. Cell counts correlated significantly and inversely with Framingham risk scores. Colony counts correlated strongly with flow-mediated brachial artery reactivity; those with the highest reactivity had counts approximately 3 times higher as those with the lowest reactivity. Counts also correlated with the response to nitroglycerin, an endothelial-independent stimulus. Multiple regression analysis showed flow-mediated brachial artery reactivity to be an independent predictor of the number of endothelial progenitor cell colonies. Senescent progenitor cells, identified using β-galactosidase, were more numerous in samples from high-risk subjects (based on the Framingham risk score) than in those from low-risk individuals. These findings support a role for circulating endothelial progenitor cells in maintaining vascular homeostasis. Continuous injury in those with cardiovascular risk factors might eventually deplete these cells.
This abridged version of the "Anthropometric Standardisation Reference Manual" contains the heart of the original manual - complete procedures for 45 anthropometric measurements. Its style enables it to be used as a supplemental text for courses in fitness assessment and exercise prescription, kinanthropometry, body composition, nutrition, and exercise physiology. It can also be used as a reference for exercise scientists. For each of the 45 measurements included in this abridged edition, readers will find complete information on the recommended technique for making the measurement, the purpose and uses for the measurement, the literature on which the measurement technique is based, and the reliability of the measurement.
This protocol describes a basic method to perform the Southern blot. Blotting allows the detection of specific molecules among a mixture separated by gel electrophoresis. Molecules are transferred from the gel to a porous membrane by capillary action using absorbent paper to soak solution through the gel and the membrane. For DNA, specific sequences are detected in the membrane by molecular hybridization with labeled nucleic acid probes. The original method, on which this protocol is based, used labeled RNAs to detect specific DNA fragments in genomic DNA that had been digested with restriction endonucleases. This protocol can be completed in 1-5 d and is inexpensive to carry out, as it requires only basic laboratory equipment.
Adverse changes in coagulation and fibrinolytic factors are thought to contribute to the increased risk of cardiovascular disease and atherothrombosis with age. We tested the hypothesis that such age-related changes in specific coagulation and fibrinolytic factors are absent in physically active women. Resting levels of plasma fibrinogen, tissue-type plasminogen activator (t-PA) antigen and activity, plasminogen activator inhibitor-1 (PAI-1) antigen and activity, and fibrin D-dimer were measured in 24 healthy premenopausal women: 11 sedentary (aged 28+/-1 years; Pre-S) and 13 physically active (aged 30+/-1 years; Pre-PA) and in 27 healthy postmenopausal women: 14 sedentary (aged 61+/-1 years; Post-S) and 13 physically active (aged 58+/-1 years; Post-PA). Post-S had higher (P<.05) fibrinogen, t-PA antigen, PAI-1 antigen, PAI-1 activity, and fibrin D-dimer levels and lower t-PA activity than Pre-S. Post-PA demonstrated lower (P<.01) plasma fibrinogen, t-PA antigen, PAI-1 antigen, and PAI-1 activity and higher (P<.01) t-PA activity levels than Post-S. In addition, plasma fibrin D-dimer levels tended (P=.06) to be lower in Post-PA than in Post-S. Although plasma levels of fibrinogen and fibrin D-dimer in Post-PA were lower than in Post-S, they were higher (P<.05) than in Pre-PA. Importantly, however, the fibrinolytic profile of Post-PA did not differ from that of Pre-PA. The results of the present study demonstrate that the adverse age-associated differences in plasma fibrinogen concentrations and the endogenous fibrinolytic system in sedentary healthy women are either attenuated or absent in highly physically active women. The smaller or absent age-related differences in coagulation and fibrinolytic factors in women who habitually exercise may represent an important mechanism contributing to their lower age-related increase in both cardiovascular disease and atherothrombotic events. Future studies need to determine whether women who are moderately active would demonstrate the same favorable hemostatic profile.
Previous measures of physical activity for epidemiologic studies were considered Inadequate to meet the needs of a community-based health education trial. Therefore, new methods of quantifying the physical activity habits of communities were developed which are practical for large health surveys, provide Information on the distribution of activity habits in the population, can detect changes in activity over time, and can be compared with other epidemiologic studies of physical activity. Independent sell-reports of vigorous activity (at least 6 metabolic equivalents (METs)), moderate activity (3–5 METs), and total energy expenditure (kilocalories per day) are described, and the physical activity practices of samples of California cities are presented. Relationships between physical activity measures and age, education, occupation, ethnicity, marital status, and body mass index are analyzed, and the reliabilities of the three activity indices are reported. The new assessment procedure is contrasted with nine other measures of physical activity used in community surveys.
Endothelial progenitor cells (EPCs) promote neovascularization and endothelial repair. Renal artery stenosis (RAS) may impair renal function by inducing intrarenal microvascular injury and remodeling. We investigated whether replenishment with EPCs would protect the renal microcirculation in chronic experimental renovascular disease.
Single-kidney hemodynamics and function were assessed with the use of multidetector computed tomography in vivo in pigs with RAS, pigs with RAS 4 weeks after intrarenal infusion of autologous EPCs, and controls. Renal microvascular remodeling and angiogenic pathways were investigated ex vivo with the use of micro-computed tomography, histology, and Western blotting. EPCs increased renal expression of angiogenic factors, stimulated proliferation and maturation of new vessels, and attenuated renal microvascular remodeling and fibrosis in RAS. Furthermore, EPCs normalized the blunted renal microvascular and filtration function.
The present study shows that a single intrarenal infusion of autologous EPCs preserved microvascular architecture and function and decreased microvascular remodeling in experimental chronic RAS. It is likely that restoration of the angiogenic cascade by autologous EPCs involved not only generation of new vessels but also acceleration of their maturation and stabilization. This contributed to preserving the blood supply, hemodynamics, and function of the RAS kidney, supporting EPCs as a promising therapeutic intervention for preserving the kidney in renovascular disease.
Cardiovascular disease (CVD) and obesity have been coupled to short telomere length in peripheral blood. The biological background to this observation is not obvious from the literature. In this study we have analyzed a large set of known risk factors for CVD in relation to telomere length in blood cells on a merged cohort of 989 individuals recruited in the Malmö Diet and Cancer Cohort (MDCC) and the Northern Sweden MONICA project. We found a significant or borderline association between obesity parameters and telomere length in women after age and center adjustments (BMI: r = -0.106, P = 0.021, weight: r = -0.087, P = 0.060, waist circumference: r = -0.099, P = 0.032, hip circumference: r = -0.128, P = 0.005). In men, a positive borderline correlation to high-density lipoprotein (HDL) (r = 0.111, P = 0.053) and a negative correlation to 2-h post-oral glucose-tolerance test (OGTT) was observed (r = -0.202, P = 0.045). In neither group any association was found between telomere length and cholesterol, serum triglycerides, serum low-density lipoprotein, plasma insulin, blood pressure, pulse pressure, or smoking habits. Our data indicate that telomere length is associated with an "obesity-phenotype" but only in women.
This study examines whether obesity accelerates atherogenic progression or adverse outcomes after coronary artery bypass graft (CABG) surgery.
Obesity is a major risk factor for developing coronary heart disease. Whether obesity accelerates disease progression after CABG is unclear.
We examined how body mass index (BMI) related to atherosclerotic graft progression and a clinical composite outcome of death, nonfatal myocardial infarction, stroke, CABG surgery, or angioplasty among 1,314 participants in the Post CABG trial. Participants who had undergone CABG surgery were randomly assigned in a 2 x 2 factorial design to warfarin versus placebo and aggressive low-density lipoprotein cholesterol (LDL-C) lowering with lovastatin 40 to 80 mg/day (to achieve LDL-C of 60 to 85 mg/dl) versus moderate LDL-C lowering with lovastatin 2.5 to 5 mg/day (to achieve LDL-C of 130 to 140 mg/dl). Angiographic progression was assessed by coronary angiography at 4 to 5 years.
Higher BMI was associated with a higher likelihood of angiographic progression (p trend = 0.003) after adjustment for demographic factors, treatment assignment, smoking status, and years since CABG surgery, but not with clinical events (p trend = 0.81). In stratified analyses, higher BMI was associated with angiographic progression in the low-dose lovastatin group (p trend <0.001) but not in the high-dose group (p = 0.03 for test for interaction of BMI and statin treatment). In the high-dose lovastatin group, higher BMI appeared to be protective against clinical events (p trend = 0.06, test of interaction: 0.02).
Higher BMI is strongly associated with atherogenic progression after CABG surgery. Aggressive statin therapy may be protective against obesity-related acceleration of coronary heart disease.
Granulocyte-colony stimulating factor (G-CSF) has been shown to have protective effects in the heart and brain. However, it may also be involved in the acute inflammatory response which may be harmful. The effects of G-CSF on endothelial cells (ECs) and the vasculature are mostly unknown. To study the possible dual effects of G-CSF on ECs, we investigated whether G-CSF induces release of C-reactive protein (CRP) by hepatocytes and whether the direct beneficial effects of G-CSF could protect ECs from the detrimental effects of CRP. G-CSF treatment significantly induced monocytes to produce IL-6, and culture supernatants of G-CSF-stimulated monocytes induced CRP production in hepatocytes. On the other hand, G-CSF directly promoted EC proliferation and migration and reversed the deleterious effects of CRP. In mechanistic analyses, G-CSF increased not only the protein expression of endothelial nitric oxide synthase (eNOS), but also its transcription. Furthermore, it enhanced eNOS phosphorylation and activation, leading to increased production of NO. Thus, G-CSF reversed the attenuated production of NO by CRP. These effects of G-CSF on eNOS transcription, translation, and activation were blunted by the PI3K inhibitor, suggesting that EC protective effects of G-CSF were associated with the activation of the Akt/eNOS pathway. In conclusion, although G-CSF induces an inflammatory reaction leading to CRP production, it has direct beneficial effects protecting ECs from the deleterious effects of CRP through activation of Akt/eNOS pathway, leading to an increase in NO production. Our data suggests that G-CSF may exert dual opposing effects on endothelial cells.
Vascular Endothelial Growth Factor-A (VEGF-A) is an endothelial-specific growth factor that induces angiogenesis, i.e., sprouting of capillaries from preexisting vessels in vivo. Endothelial nitric oxide synthase (eNOS) is an essential molecule in mediating VEGF-A-induced angiogenesis and endothelial function via production of nitric oxide (NO). Moreover, the protein level of eNOS is upregulated in response to VEGF-A. While VEGF-A-induced NO release in human trophoblast cells appears to be initiated via VEGF receptor-1, it is not clear which of the VEGF-receptors is mediating the signal for induction of eNOS protein expression. In addition, it is unclear whether other NOS isoforms are upregulated in response to VEGF-A stimulation. To address these questions, we stimulated human umbilical vein endothelial cells (HUVEC) with VEGF-A for 24 hours and evaluated expression of eNOS and iNOS protein. VEGF-A induces expression of both members of the NOS family. Using porcine aortic endothelial cells overexpressing either VEGF receptor-2 (PAE/KDR cells) or VEGF receptor-1 (PAE/Flt-1 cells), we have studied the regulation of iNOS and eNOS expression in response to VEGF-A stimulation. The activation of VEGF receptor-2 leads to an upregulation of both eNOS and iNOS protein, while stimulation of VEGF receptor-1 did not generate such a signal. Therefore, only VEGF receptor-2 mediates stimulation of eNOS and iNOS expression. We conclude that the two VEGF receptors have different and distinct functions regarding NO formation and NO release during VEGF-A-induced angiogenesis.
Direct transfection of ischemic myocardium with naked plasmid DNA encoding for vascular endothelial growth factor-165 (VEGF165) has been shown to mobilize endothelial progenitor cells (EPCs). This study examined the kinetics of circulating EPCs isolated from peripheral blood mononuclear cells after gene transfer, and their role in neovascularization of ischemic myocardium.
The mononuclear cell population was isolated from peripheral venous blood samples of patients with functional class III or IV angina receiving intramyocardial VEGF165 gene transfer. Peripheral blood mononuclear cells were examined by an in vitro EPC culture assay and fluorescent-activated cell sorting. The data were compared with a control group consisting of patients who had undergone off-pump coronary artery bypass grafting without receiving gene transfer.
Coinciding with a rise in VEGF levels, mobilization of EPCs increased significantly over base line for 9 weeks after the treatment (121+/-14 cells/mm2 versus 36.8+/-8 cells/mm2, p < 0.0005), followed by a subsequent decrease. Fluorescent-activated cell sorting analysis confirmed culture assay data, with a statistically significant rise in cells expressing vascular endothelial-cadherin, CD51/61 [alphavbeta3], CD62E [E-selectin], CD34, and KDR. The control group failed to show significant mobilization of EPCs.
Mobilization of EPCs with resultant postnatal vasculogenesis, may play a role in revascularizing ischemic myocardium following human gene transfer with VEGF165.
Recent studies provide increasing evidence that postnatal neovascularization involves bone marrow-derived circulating endothelial progenitor cells (EPCs). The regulation of EPCs in patients with coronary artery disease (CAD) is unclear at present. Therefore, we determined the number and functional activity of EPCs in 45 patients with CAD and 15 healthy volunteers. The numbers of isolated EPCs and circulating CD34/kinase insert domain receptor (KDR)-positive precursor cells were significantly reduced in patients with CAD by approximately 40% and 48%, respectively. To determine the influence of atherosclerotic risk factors, a risk factor score including age, sex, hypertension, diabetes, smoking, positive family history of CAD, and LDL cholesterol levels was used. The number of risk factors was significantly correlated with a reduction of EPC levels (R=-0.394, P=0.002) and CD34-/KDR-positive cells (R=-0.537, P<0.001). Analysis of the individual risk factors demonstrated that smokers had significantly reduced levels of EPCs (P<0.001) and CD34-/KDR-positive cells (P=0.003). Moreover, a positive family history of CAD was associated with reduced CD34-/KDR-positive cells (P=0.011). Most importantly, EPCs isolated from patients with CAD also revealed an impaired migratory response, which was inversely correlated with the number of risk factors (R=-0.484, P=0.002). By multivariate analysis, hypertension was identified as a major independent predictor for impaired EPC migration (P=0.043). The present study demonstrates that patients with CAD revealed reduced levels and functional impairment of EPCs, which correlated with risk factors for CAD. Given the important role of EPCs for neovascularization of ischemic tissue, the decrease of EPC numbers and activity may contribute to impaired vascularization in patients with CAD. The full text of this article is available at http://www.circresaha.org.
This review describes the structure of telomeres, the protective DNA-protein complexes at eukaryotic chromosomal ends, and several molecular mechanisms involved in telomere functions. Also discussed are cellular responses to compromising the functions of telomeres and of telomerase, which synthesizes telomeric DNA.
Primary and secondary prevention trials suggest that statins possess favorable effects independent of cholesterol reduction. We investigated whether statin therapy may also accelerate reendothelialization after carotid balloon injury.
Simvastatin treatment in 34 male Sprague-Dawley rats accelerated reendothelialization of the balloon-injured arterial segments (reendothelialized area at 2 weeks, 12.3+/-1.8 versus 5.4+/-1.1 mm2, P< 0.01) and resulted in a dose-dependent (0.2 or 1 mg/kg IP) significant reduction in neointimal thickening at 2, 3, and 4 weeks compared with saline-injected controls (n=18). To elucidate the mechanism, we investigated the contribution of bone marrow-derived endothelial progenitor cells (EPCs) by bone marrow transplantation from Tie2/lacZ mice to background mice or nude rats. X-gal staining of mouse carotid artery specimens revealed a 2.9-fold increase in the number of beta-gal-positive cells per square millimeter appearing on the carotid artery luminal surface at 2 weeks, and double-fluorescence immunohistochemistry disclosed a significant 5-fold increase in the number of double-positive cells (beta-gal, isolectin B4) on the luminal surface in carotid arteries of statin-treated nude rats (20+/-3 versus 4+/-1 cells/mm surface length, P<0.005). Statins increased circulating rat EPCs (2.4-fold at 2 weeks and 2.5-fold at 4 weeks, P<0.001) and induced adhesiveness of cultured human EPCs by upregulation of the integrin subunits alpha5, beta1, alpha(v), and beta5 of human EPCs as shown by reverse transcription-polymerase chain reaction and fluorescence-activated cell sorting.
These findings establish additional mechanisms by which statins may specifically preempt disordered vascular wall pathology and constitute physiological evidence that EPC mobilization represents a functionally relevant consequence of statin therapy.
To determine the clinical conditions associated with systemic oxidative stress in a community-based cohort. Information regarding cardiovascular risk factors associated with systemic oxidative stress has largely been derived from highly selected samples with advanced stages of vascular disease. Thus, it has been difficult to evaluate the relative contribution of each cardiovascular risk factor to systemic oxidative stress and to determine whether such risk factors act independently and are applicable to the general population.
We examined 2828 subjects from the Framingham Heart Study and measured urinary creatinine-indexed levels of 8-epi-PGF2alpha as a marker of systemic oxidative stress. Age- and sex-adjusted multivariable regression models were used to assess clinical correlates of oxidative stress. In age- and sex-adjusted models, increased urinary creatinine-indexed 8-epi-PGF2alpha levels were positively associated with female sex, hypertension treatment, smoking, diabetes, blood glucose, body mass index, and a history of cardiovascular disease. In contrast, age and total cholesterol were negatively correlated with urinary creatinine-indexed 8-epi-PGF2alpha levels. After adjustment for several covariates, decreasing age and total/HDL cholesterol ratio, sex, smoking, body mass index, blood glucose, and cardiovascular disease remained associated with urinary 8-epi-PGF2alpha levels.
Smoking, diabetes, and body mass index were highly associated with systemic oxidative stress as determined by creatinine-indexed urinary 8-epi-PGF2alpha levels. The effect of body mass index was minimally affected by blood glucose, and diabetes and may suggest an important role of oxidative stress in the deleterious impact of obesity on cardiovascular disease.
Transplantation of endothelial progenitor cells (EPCs) improves vascularization and left ventricular function after experimental myocardial ischemia. However, tissue distribution of transplanted EPCs has not yet been monitored in living animals. Therefore, we tested whether radioactive labeling allows us to detect injected EPCs.
Human EPCs were isolated from peripheral blood, characterized by expression of endothelial marker proteins, and radioactively labeled with [111In]indium oxine. EPCs (106) were injected in athymic nude rats 24 hours after myocardial infarction (n=8) or sham operation (n=8). Scintigraphic images were acquired after 1, 24, 48, and 96 hours after EPC injection. Animals were then killed, and specific radioactivity was measured in different tissues. At 24 to 96 hours after intravenous injection of EPCs, approximately 70% of the radioactivity was localized in the spleen and liver, with only approximately 1% of the radioactivity identified in the heart of sham-operated animals. After myocardial infarction, the heart-to-muscle radioactivity ratio increased significantly, from 1.02+/-0.19 in sham-operated animals to 2.03+/-0.37 after intravenous administration of EPCs. Injection of EPCs into the left ventricular cavity increased this ratio profoundly, from 2.69+/-1.54 in sham-operated animals to 4.70+/-1.55 (P<0.05) in rats with myocardial infarction. Immunostaining of cryosections from infarcted hearts confirmed that EPCs homed predominantly to the infarct border zone.
Although only a small proportion of radiolabeled EPCs are detected in nonischemic myocardium, myocardial infarction increases homing of transplanted EPCs in vivo profoundly. Radiolabeling might eventually provide an useful tool for monitoring the fate of transplanted progenitor cells and for clinical cell therapy.
Cells with endothelial phenotype generated from adult peripheral blood have emerging diagnostic and therapeutic potential. This study examined the lineage relationship between, and angiogenic function of, early endothelial progenitor cells (EPCs) and late outgrowth endothelial cells (OECs) in culture. Culture conditions were established to support the generation of both EPCs and OECs from the same starting population of peripheral blood mononuclear cells (PBMCs). Utilizing differences in expression of the surface endotoxin receptor CD14, it was determined that the vast majority of EPCs arose from a CD14+ subpopulation of PBMCs but OECs developed exclusively from the CD14- fraction. Human OECs, but not EPCs, expressed key regulatory proteins endothelial nitric oxide synthase (eNOS) and caveolin-1. Moreover, OECs exhibited a markedly greater capacity for capillary morphogenesis in in vitro and in vivo matrigel models, tube formation by OECs being in part dependent on eNOS function. Collectively, these data indicate lineage and functional heterogeneity in the population of circulating cells capable of assuming an endothelial phenotype and provide rationale for the investigation of new cell-therapeutic approaches to ischemic cardiovascular disease.
Myocardial ischemia provides a potent stimulus to angiogenesis, and the mobilization and differentiation of endothelial progenitor cells (EPCs) has been shown to be important in this process. An elevated level of C-reactive protein (CRP) has emerged as one of the most powerful predictors of cardiovascular disease. However, the impact of CRP on EPC biology is unknown.
EPCs were isolated from the peripheral venous blood of healthy male volunteers. Cells were cultured in endothelial cell basal medium-2 in the absence and presence of CRP (5 to 20 microg/mL), rosiglitazone (1 micromol/L), and/or vascular endothelial growth factor. EPC differentiation, survival, and function were assayed. CRP at concentrations > or =15 microg/mL significantly reduced EPC cell number, inhibited the expression of the endothelial cell-specific markers Tie-2, EC-lectin, and VE-cadherin, significantly increased EPC apoptosis, and impaired EPC-induced angiogenesis. EPC-induced angiogenesis was dependent on the presence of nitric oxide, and CRP treatment caused a decrease in endothelial nitric oxide synthase mRNA expression by EPCs. However, all of these detrimental CRP-mediated effects on EPCs were attenuated by pretreatment with rosiglitazone, a peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist.
Human recombinant CRP, at concentrations known to predict adverse vascular outcomes, directly inhibits EPC differentiation, survival, and function, key components of angiogenesis and the response to chronic ischemia. This occurs in part via an effect of CRP to reduce EPC eNOS expression. The PPARgamma agonist rosiglitazone inhibits the negative effects of CRP on EPC biology. The ability of CRP to inhibit EPC differentiation and survival may represent an important mechanism that further links inflammation to cardiovascular disease.
Infusion of different hematopoietic stem cell populations and ex vivo expanded endothelial progenitor cells augments neovascularization of tissue after ischemia and contributes to reendothelialization after endothelial injury, thereby, providing a novel therapeutic option. However, controversy exists with respect to the identification and the origin of endothelial progenitor cells. Overall, there is consensus that endothelial progenitor cells can derive from the bone marrow and that CD133/VEGFR2 cells represent a population with endothelial progenitor capacity. However, increasing evidence suggests that there are additional bone marrow-derived cell populations (eg, myeloid cells, "side population" cells, and mesenchymal cells) and non-bone marrow-derived cells, which also can give rise to endothelial cells. The characterization of the different progenitor cell populations and their functional properties are discussed. Mobilization and endothelial progenitor cell-mediated neovascularization is critically regulated. Stimulatory (eg, statins and exercise) or inhibitory factors (risk factors for coronary artery disease) modulate progenitor cell levels and, thereby, affect the vascular repair capacity. Moreover, recruitment and incorporation of endothelial progenitor cells requires a coordinated sequence of multistep adhesive and signaling events including adhesion and migration (eg, by integrins), chemoattraction (eg, by SDF-1/CXCR4), and finally the differentiation to endothelial cells. This review summarizes the mechanisms regulating endothelial progenitor cell-mediated neovascularization and reendothelialization.
The integrity and functional activity of the endothelial monolayer play a crucial role in the prevention of atherosclerosis. Increasing evidence suggests that risk factors for coronary artery disease increase endothelial cell apoptosis and lead to a disturbance in the endothelial monolayer. Recent insights suggest that the injured endothelial monolayer is regenerated by circulating bone marrow derived endothelial progenitor cells, which accelerates reendothelialization and limits atherosclerotic lesion formation. However, risk factors for coronary artery disease such as age and diabetes reduce the number and functional activity of these circulating endothelial progenitor cells, thus limiting the regenerative capacity. The impairment of stem/progenitor cells by risk factors may contribute to atherogenesis and atherosclerotic disease progression. We discuss this novel concept of endothelial regeneration and highlight possible novel strategies to interfere with the balance of injury and repair mechanisms.
The maintenance of endothelial integrity plays a critical role in preventing atherosclerotic disease progression. Endothelial progenitor cells (EPCs) were experimentally shown to incorporate into sites of neovascularization and home to sites of endothelial denudation. Circulating EPCs may thus provide an endogenous repair mechanism to counteract ongoing risk factor-induced endothelial injury and to replace dysfunctional endothelium.
In 120 individuals (43 control subjects, 44 patients with stable coronary artery disease, and 33 patients with acute coronary syndromes), circulating EPCs were defined by the surface markers CD34+KDR+ and analyzed by flow cytometry. Cardiovascular events (cardiovascular death, unstable angina, myocardial infarction, PTCA, CABG, or ischemic stroke) served as outcome variables over a median follow-up period of 10 months. Patients suffering from cardiovascular events had significantly lower numbers of EPCs (P<0.05). Reduced numbers of EPCs were associated with a significantly higher incidence of cardiovascular events by Kaplan-Meier analysis (P=0.0009). By multivariate analysis, reduced EPC levels were a significant, independent predictor of poor prognosis, even after adjustment for traditional cardiovascular risk factors and disease activity (hazard ratio, 3.9; P<0.05).
Reduced levels of circulating EPCs independently predict atherosclerotic disease progression, thus supporting an important role for endogenous vascular repair to modulate the clinical course of coronary artery disease.
To investigate the relationship between serum concentrations of the cytokines C-reactive protein (CRP), tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6, and obesity and visceral adiposity.
A cross-sectional study of 100 Korean adults free from pre-existing inflammatory disease or cancer was performed. Body mass index (BMI), waist circumference, and serum concentrations of CRP, TNF-alpha and IL-6 were measured. In 46 obese subjects, fat mass was assessed by bioimpedance analysis and abdominal fat distribution was determined by computerized tomography scan.
Overall, serum concentrations of CRP, TNF-alpha and IL-6 were significantly correlated with weight, BMI, waist circumference, hip circumference, and waist-hip ratio. In obese subjects, CRP and IL-6 were significantly correlated with BMI, waist circumference and visceral adipose tissue. Multiple regression analysis showed that CRP was significantly associated with BMI, whereas IL-6 was significantly related with visceral adiposity in obese subjects.
The positive associations of obesity and visceral adiposity with elevated cytokine levels suggest the importance of reducing obesity and visceral adiposity to prevent elevations in cytokine levels.
Endothelial progenitor cells derived from bone marrow are believed to support the integrity of the vascular endothelium. The number and function of endothelial progenitor cells correlate inversely with cardiovascular risk factors, but the prognostic value associated with circulating endothelial progenitor cells has not been defined.
The number of endothelial progenitor cells positive for CD34 and kinase insert domain receptor (KDR) was determined with the use of flow cytometry in 519 patients with coronary artery disease as confirmed on angiography. After 12 months, we evaluated the association between baseline levels of endothelial progenitor cells and death from cardiovascular causes, the occurrence of a first major cardiovascular event (myocardial infarction, hospitalization, revascularization, or death from cardiovascular causes), revascularization, hospitalization, and death from all causes.
A total of 43 participants died, 23 from cardiovascular causes. A first major cardiovascular event occurred in 214 patients. The cumulative event-free survival rate increased stepwise across three increasing baseline levels of endothelial progenitor cells in an analysis of death from cardiovascular causes, a first major cardiovascular event, revascularization, and hospitalization. After adjustment for age, sex, vascular risk factors, and other relevant variables, increased levels of endothelial progenitor cells were associated with a reduced risk of death from cardiovascular causes (hazard ratio, 0.31; 95 percent confidence interval, 0.16 to 0.63; P=0.001), a first major cardiovascular event (hazard ratio, 0.74; 95 percent confidence interval, 0.62 to 0.89; P=0.002), revascularization (hazard ratio, 0.77; 95 percent confidence interval, 0.62 to 0.95; P=0.02), and hospitalization (hazard ratio, 0.76; 95 percent confidence interval, 0.63 to 0.94; P=0.01). Endothelial progenitor-cell levels were not predictive of myocardial infarction or of death from all causes.
The level of circulating CD34+KDR+ endothelial progenitor cells predicts the occurrence of cardiovascular events and death from cardiovascular causes and may help to identify patients at increased cardiovascular risk.
Circulating endothelial progenitor cells (EPC) are incorporated into newly formed capillaries, enhance neovascularization after hind limb ischemia and improve cardiac function after ischemic injury. Incorporated progenitor cells may also promote neovascularization and cardiac regeneration by releasing factors, which act in a paracrine manner to support local angiogenesis and mobilize tissue residing progenitor cells. Therefore, we analyzed the expression profile of cytokines in human peripheral blood-derived EPC as opposed to human umbilical vein endothelial cells (HUVEC), human microvascular endothelial cells (HMVEC), and CD14(+) monocytes by microarray technology. A gene tree analysis revealed a distinct expression pattern of angiogenic growth factors in EPC, mature endothelial cells, and CD14(+) monocytes. VEGF-A, VEGF-B, SDF-1, and IGF-1 mRNA levels were higher in EPC as compared to HUVEC or HMVEC. The enhanced mRNA expression was paralleled by a significant release of VEGF, SDF-1, and IGF-1 protein into the cell culture supernatant of EPC. Moreover, immunohistological analysis of ischemic limbs from nude rats revealed that VEGF is also released from recruited human EPC in vivo. As a functional consequence, conditioned medium of EPC induced a strong migratory response of mature endothelial cells, which was significantly inhibited by VEGF and SDF-1 neutralizing antibodies. Finally, conditioned medium of EPC significantly stimulated the migration of cardiac resident c-kit(+) progenitor cells in vitro. Taken together, EPC exhibit a high expression of angiogenic growth factors, which enhanced migration of mature endothelial cells and tissue resident cardiac progenitor cells. In addition to the physical contribution of EPC to newly formed vessels, the enhanced expression of cytokines may be a supportive mechanism to improve blood vessel formation and cardiac regeneration after cell therapy.
Bone marrow-derived cells (BMCs) have been implicated as a modifiers of vascular growth either directly by transdifferentiation into endothelial cells (ECs) or indirectly through growth factor release. To examine these possibilities under physiological conditions, we developed a model of hypoxia-mediated angiogenesis in the mouse spinotrapezius muscle. This allows whole-mount analysis; therefore, the morphology and location of BMCs within the vascular network may be observed along with differentiation markers. We exposed bone marrow transplant chimeric mice to hypoxia and treated a subset with granulocyte macrophage colony-stimulating factor. Exposure to hypoxia caused an 13% increase in capillary density relative to control. Hypoxia did not increase the overall number of muscle-resident BMCs, but did increase the number of rounded BMCs by 25%. There was no discernable BMC contribution to the endothelium, although some BMCs assumed a pericyte morphology around capillaries. Granulocyte macrophage colony-stimulating factor treatment further increased the number of round BMCs within the muscle and caused a 23% increase in angiogenesis. The results of this study suggest a potentially beneficial action of BMCs during hypoxia through paracrine release of growth factors but not transdifferentiation into ECs.
Considering experimental evidence that stem cells enhance myocardial regeneration and granulocyte colony-stimulating factor (G-CSF) mediates mobilization of CD34+ mononuclear blood stem cells (MNCCD34+), we tested the impact of G-CSF integrated into primary percutaneous coronary intervention (PCI) management of acute myocardial infarction in man.
Fifty consecutive patients with ST-segment elevation myocardial infarction were subjected to primary PCI stenting with abciximab and followed up for 6 months; 89+/-35 minutes after successful PCI, 25 patients were randomly assigned in this pilot study (PROBE design) to receive subcutaneous G-CSF at 10 microg/kg body weight for 6 days in addition to standard care, including aspirin, clopidogrel, an ACE inhibitor, beta-blocking agents, and statins. By use of CellQuest software on peripheral blood samples incubated with CD45 and CD34, mobilized MNCCD34+ were quantified on a daily basis. With homogeneous demographics and clinical and infarct-related characteristics, G-CSF stimulation led to mobilization of MNCCD34+ to between 3.17+/-2.93 MNCCD34+/microL at baseline and 64.55+/-37.11 MNCCD34+/microL on day 6 (P<0.001 versus control); there was no indication of leukocytoclastic effects, significant pain, impaired rheology, inflammatory reactions, or accelerated restenosis at 6 months. Within 35 days, G-CSF and MNCCD34+ liberation led to enhanced resting wall thickening in the infarct zone of between 0.29+/-0.22 and 0.99+/-0.32 mm versus 0.49+/-0.29 mm in control subjects (P<0.001); under inotropic challenge with dobutamine (10 microg.kg(-1).min(-1)), wall motion score index showed improvement from 1.66+/-0.23 to 1.41+/-0.21 (P<0.004 versus control) and to 1.35+/-0.24 after 4 months (P<0.001 versus control), respectively, coupled with sustained recovery of wall thickening to 1.24+/-0.31 mm (P<0.001 versus control) at 4 months. Accordingly, resting wall motion score index improved with G-CSF to 1.41+/-0.25 (P<0.001 versus control), left ventricular end-diastolic diameter to 55+/-5 mm (P<0.002 versus control), and ejection fraction to 54+/-8% (P<0.001 versus control) after 4 months. Morphological and functional improvement with G-CSF was corroborated by enhanced metabolic activity and 18F-deoxyglucose uptake in the infarct zone (P<0.001 versus control).
G-CSF and mobilization of MNC(CD34+) after reperfusion of infarcted myocardium may offer a pragmatic strategy for preservation of myocardium and prevention of remodeling without evidence of aggravated restenosis.
Obesity is becoming a global epidemic in both children and adults. It is associated with numerous comorbidities such as cardiovascular diseases (CVD), type 2 diabetes, hypertension, certain cancers, and sleep apnea/sleep-disordered breathing. In fact, obesity is an independent risk factor for CVD, and CVD risks have also been documented in obese children. Obesity is associated with an increased risk of morbidity and mortality as well as reduced life expectancy. Health service use and medical costs associated with obesity and related diseases have risen dramatically and are expected to continue to rise. Besides an altered metabolic profile, a variety of adaptations/alterations in cardiac structure and function occur in the individual as adipose tissue accumulates in excess amounts, even in the absence of comorbidities. Hence, obesity may affect the heart through its influence on known risk factors such as dyslipidemia, hypertension, glucose intolerance, inflammatory markers, obstructive sleep apnea/hypoventilation, and the prothrombotic state, in addition to as-yet-unrecognized mechanisms. On the whole, overweight and obesity predispose to or are associated with numerous cardiac complications such as coronary heart disease, heart failure, and sudden death because of their impact on the cardiovascular system. The pathophysiology of these entities that are linked to obesity will be discussed. However, the cardiovascular clinical evaluation of obese patients may be limited because of the morphology of the individual. In this statement, we review the available evidence of the impact of obesity on CVD with emphasis on the evaluation of cardiac structure and function in obese patients and the effect of weight loss on the cardiovascular system.
The aim of this study was to investigate the effect of granulocyte colony-stimulating factor (G-CSF) on chronic myocardial ischemia in swine.
We recently have reported that G-CSF prevents cardiac remodeling and dysfunction after acute myocardial infarction in mice and swine. It remains unclear whether G-CSF has beneficial effects on chronic myocardial ischemia.
An ameroid constrictor was placed on left circumflex coronary artery of swine. The presence of myocardial ischemia was verified at four weeks after the operation, and the animals were randomly assigned into the following two groups: 1) administration of vehicle (control group, n = 10), and 2) administration of G-CSF (10 microg/kg/day) for seven days (G-CSF group, n = 10).
Echocardiographic examination revealed that the G-CSF treatment prevented left ventricular dilation and dysfunction at eight weeks after the operation. Stress echocardiography revealed that G-CSF ameliorated the regional contractility of chronic myocardial ischemia. Morphological analysis revealed that the extent of myocardial fibrosis of the ischemic region was less in the G-CSF group than in control group. There were more vessels and less apoptotic cells at the ischemic region of the heart of the G-CSF group than control group. Moreover, Akt1 was more strongly activated in the heart of the G-CSF group than control group.
These findings suggest that G-CSF improves cardiac function of chronic myocardial ischemia through decreases in fibrosis and apoptotic death and an increase in vascular density in the ischemic region.
The defense mechanisms of endothelial cells (EC) against reactive oxygen species (ROS) are insufficiently characterized. We have addressed the hypothesis that vascular endothelial growth factor (VEGF) and its receptors are relevant elements in this response. Cell viability, VEGF and VEGF receptor (VEGFR1 and VEGFR2) expression, and transcription factor activation were studied on transient exposure of monolayer EC to H2O2. Wild-type and mutant inhibitors of kappaBalpha (IkappaBalpha) constructions were used to further assess the role of NF-kappaB in the induction of VEGFR2 expression. A concentration of H2O2>or=60 microM elicited clear-cut damaging effects on EC, whereas lower concentrations (2-4 microM) were cytoprotective. The cytoprotective effect was shifted to an EC-damaging pattern by means of specific VEGF blockade, therefore revealing a major role of autologous VEGF. Exposure to H2O2 increased VEGF and VEGFR2 mRNA and protein in EC, without affecting VEGFR1 expression. Also, H2O2 challenge was accompanied by increased NF-kappaB, activator protein-1, and specific protein-1 nuclear binding. A role of NF-kappaB as the mediator of the H2O2 induction of VEGFR2 mRNA expression was supported by inhibition by the ROS scavenger pyrrolidine dithiocarbamate and by the blocking effect of transfected IkappaBalpha. Exposure to exogenous VEGF also increased VEGFR2 and induced NF-kappaB in EC. In summary, autologous VEGF is instrumental for EC protection induced by low concentrations of ROS. ROS induce expression not only of VEGF but also of VEGFR2. VEGFR2 increase by ROS is mainly driven through a NF-kappaB-dependent pathway.
Accumulation of cellular damage with advancing age leads to atherothrombosis and associated cardiovascular disease. Ageing is also characterized by shortening of the DNA component of telomeres, the specialized genetic segments located at the end of eukaryotic chromosomes that protect them from end-to-end fusions. By inducing genomic instability, replicative senescence and apoptosis, shortening of the telomeric DNA is thought to contribute to organismal ageing. In this Review, we discuss experimental and human studies that have linked telomeres and associated proteins to several factors which influence cardiovascular risk (eg, estrogens, oxidative stress, hypertension, diabetes, and psychological stress), as well as to neovascularization and the pathogenesis of atherosclerosis and heart disease. Two chief questions that remain unanswered are whether telomere shortening is cause or consequence of cardiovascular disease, and whether therapies targeting the telomere may find application in treating these disorders (eg, cell "telomerization" to engineer blood vessels of clinical value for bypass surgery, and to facilitate cell-based myocardial regeneration strategies). Given that most research to date has focused on the role of telomerase, it is also of up most importance to investigate whether alterations in additional telomere-associated proteins may contribute to the pathogenesis of cardiovascular disease.
The important role of the vascular endothelium in cardiovascular health is increasingly recognized. However, mature endothelial cells possess limited regenerative capacity. There is therefore much interest in circulating endothelial progenitor cells (EPCs) among the scientific community, especially into their purported role in maintenance of endothelial integrity and function, as well as postnatal neovascularization. It has been suggested that these cells might not only be responsible for the continuous recovery of the endothelium after injury/damage, but also might take part in angiogenesis, giving the hope of new treatment opportunities. Indeed, there is accumulating evidence showing reduced availability and impaired EPC function in the presence of both cardiovascular disease and associated comorbid risk factors. Thus, many studies into the potential for use of EPCs in the clinical setting are being undertaken. The goal of this review article is to provide an overview of data relevant to the clinical role of EPCs and perspectives for treatment of cardiovascular disorders.