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Physiology and Pathophysiology of Carnosine
Abstract
Carnosine (β-alanyl-l-histidine) was discovered in 1900 as an abundant non-protein nitrogen-containing compound of meat. The dipeptide is not only found in skeletal muscle, but also in other excitable tissues. Most animals, except humans, also possess a methylated variant of carnosine, either anserine or ophidine/balenine, collectively called the histidine-containing dipeptides. This review aims to decipher the physiological roles of carnosine, based on its biochemical properties. The latter include pH-buffering, metal-ion chelation, and antioxidant capacity as well as the capacity to protect against formation of advanced glycation and lipoxidation end-products. For these reasons, the therapeutic potential of carnosine supplementation has been tested in numerous diseases in which ischemic or oxidative stress are involved. For several pathologies, such as diabetes and its complications, ocular disease, aging, and neurological disorders, promising preclinical and clinical results have been obtained. Also the pathophysiological relevance of serum carnosinase, the enzyme actively degrading carnosine into l-histidine and β-alanine, is discussed. The carnosine system has evolved as a pluripotent solution to a number of homeostatic challenges. l-Histidine, and more specifically its imidazole moiety, appears to be the prime bioactive component, whereas β-alanine is mainly regulating the synthesis of the dipeptide. This paper summarizes a century of scientific exploration on the (patho)physiological role of carnosine and related compounds. However, far more experiments in the fields of physiology and related disciplines (biology, pharmacology, genetics, molecular biology, etc.) are required to gain a full understanding of the function and applications of this intriguing molecule.
... We report here a sex dependence in terms of metabolic disturbance that produced a proportionally greater transcriptional and phenotypic response in females. The smaller propionyl-CoA excess in male PA hearts related to higher levels of β-alanine, a rate-limiting precursor of carnosine that serves as a major antioxidant in the heart 28 . We speculate a role for these actions in hearts under metabolic stresses that influence propionate metabolism. ...
... We found that the metabolic disturbance associated with propionyl-CoA is less profound in male PA hearts and associates with a higher buildup of β-alanine. This non-proteinogenic amino acid can be synthesised from propionyl-CoA and is the rate-limiting precursor of carnosine and anserine-dipeptides with well-established antioxidant 35 and pH/Ca 2+ -buffering 36 properties in the heart 28 . The lower propionyl-CoA excess in male PA hearts may be explained by augmented production capacity of carnosine; indeed, overexpression of carnosine synthase in mice reduced cardiac propionate levels 35 . ...
... β-alanine, a downstream derivative of propionyl-CoA, is a rate-limiting precursor of carnosine 35 . Through the actions of testosterone, male mice accumulate more carnosine in skeletal muscle 49 , and a similar mechanism is thought to operate in the heart 28 . We traced propionate to carnosine in vitro and propose that this pathway is scaled-up in male PA hearts. ...
Propiogenic substrates and gut bacteria produce propionate, a post-translational protein modifier. In this study, we used a mouse model of propionic acidaemia (PA) to study how disturbances to propionate metabolism result in histone modifications and changes to gene expression that affect cardiac function. Plasma propionate surrogates were raised in PA mice, but female hearts manifested more profound changes in acyl-CoAs, histone propionylation and acetylation, and transcription. These resulted in moderate diastolic dysfunction with raised diastolic Ca ²⁺ , expanded end-systolic ventricular volume and reduced stroke volume. Propionate was traced to histone H3 propionylation and caused increased acetylation genome-wide, including at promoters of Pde9a and Mme , genes related to contractile dysfunction through downscaled cGMP signaling. The less severe phenotype in male hearts correlated with β-alanine buildup. Raising β-alanine in cultured myocytes treated with propionate reduced propionyl-CoA levels, indicating a mechanistic relationship. Thus, we linked perturbed propionate metabolism to epigenetic changes that impact cardiac function.
... Numerous studies show that Car, an endogenous dipeptide and over-the-counter food supplement, and its compounds exert beneficial effects on bone and cartilage under physiological and pathological conditions (Table 3) [9]. Car is present at high levels (in millimolar concentration) in the nervous, cardiac, and muscular tissues [190]. It is synthesized by carnosine synthase 1 (CARNS1) from β-alanine and L-histidine, while its hydrolysis is catalyzed by two isoforms of carnosinases (CN1 and CN2) (Figure 4). ...
... It is synthesized by carnosine synthase 1 (CARNS1) from β-alanine and L-histidine, while its hydrolysis is catalyzed by two isoforms of carnosinases (CN1 and CN2) (Figure 4). Car is largely studied due to its numerous and always new biological properties [190]. Its pH-buffering activity, the ability to form complexes with metal ions, including Cu 2+ and Zn 2+ ions, and its antioxidant, anti-inflammatory, antiaging, antiglycation, and antiaggregating properties are worthy of mention [190]. ...
... Car is largely studied due to its numerous and always new biological properties [190]. Its pH-buffering activity, the ability to form complexes with metal ions, including Cu 2+ and Zn 2+ ions, and its antioxidant, anti-inflammatory, antiaging, antiglycation, and antiaggregating properties are worthy of mention [190]. Furthermore, numerous findings suggest that Car modulates macrophage functions, immune cells activated under inflammatory states, and oxidative stress. ...
Dysregulated metal homeostasis is associated with many pathological conditions, including arthritic diseases. Osteoarthritis and rheumatoid arthritis are the two most prevalent disorders that damage the joints and lead to cartilage and bone destruction. Recent studies show that the levels of zinc (Zn) and copper (Cu) are generally altered in the serum of arthritis patients. Therefore, metal dyshomeostasis may reflect the contribution of these trace elements to the disease’s pathogenesis and manifestations, suggesting their potential for prognosis and treatment. Carnosine (Car) also emerged as a biomarker in arthritis and exerts protective and osteogenic effects in arthritic joints. Notably, its zinc(II) complex, polaprezinc, has been recently proposed as a drug-repurposing candidate for bone fracture healing. On these bases, this review article aims to provide an overview of the beneficial roles of Cu and Zn in bone and cartilage health and their potential application in tissue engineering. The effects of Car and polaprezinc in promoting cartilage and bone regeneration are also discussed. We hypothesize that polaprezinc could exchange Zn for Cu, present in the culture media, due to its higher sequestering ability towards Cu. However, future studies should unveil the potential contribution of Cu in the beneficial effects of polaprezinc.
... In this review, we analyzed the literature with particular regard to breast cancer treatment using carnosine and its potential therapeutic effects. Carnosine is a naturally endogenous dipeptide that is present at high concentrations in several tissues, particularly in the cardiac and skeletal muscles [4,5], as well as in the brain [6]. The concentrations of carnosine in cells are regulated via the activity of two different carnosinases [7]. ...
... Numerous studies have reported the ability of the dipeptide carnosine to exert different biological and physiological roles through its well-known multimodal mechanism of action. Most of the carnosine (about 99%) is localized in muscle tissues [4], which is why there are a plethora of research studies that have investigated its activities in muscles, and in particular the benefits to the athletic performance related to carnosine (or its precursor β-alanine) supplementation. In this context, carnosine has been shown to facilitate the detoxification of muscles from lactic acid accumulation [14], to act as an endogenous antidote [15], and to improve both cellular ion/proton exchange [16], as well as contraction and mechanical work production in muscles [17,18]. ...
... Nonetheless, one of the remaining challenges of using carnosine as a therapeutic agent could be represented by the presence of the CNDP1 and CNDP2 carnosinases, which are responsible for the minimal increase in circulating carnosine levels in humans after its administration, thus limiting the therapeutic potential of this dipeptide. It is possible that the highly promising results obtained in studies using mice and rats could represent an over-estimation of the therapeutic potential of carnosine, given that rodents do not express CNDP1 [4]. ...
Carnosine is an endogenous dipeptide composed of β-alanine and L-histidine, possessing a multimodal pharmacodynamic profile that includes anti-inflammatory and anti-oxidant activities. Carnosine has also shown its ability to modulate cell proliferation, cell cycle arrest, apoptosis, and even glycolytic energy metabolism, all processes playing a key role in the context of cancer. Cancer is one of the most dreaded diseases of the 20th and 21st centuries. Among the different types of cancer, breast cancer represents the most common non-skin cancer among women, accounting for an estimated 15% of all cancer-related deaths in women. The main aim of the present review was to provide an overview of studies on the anti-cancer activity of carnosine, and in particular its activity against breast cancer. We also highlighted the possible advantages and limitations involved in the use of this dipeptide. The first part of the review entailed a brief description of carnosine’s biological activities and the pathophysiology of cancer, with a focus on breast cancer. The second part of the review described the anti-tumoral activity of carnosine, for which numerous studies have been carried out, especially at the preclinical level, showing promising results. However, only a few studies have investigated the therapeutic potential of this dipeptide for breast cancer prevention or treatment. In this context, carnosine has shown to be able to decrease the size of cancer cells and their viability. It also reduces the levels of vascular endothelial growth factor (VEGF), cyclin D1, NAD+, and ATP, as well as cytochrome c oxidase activity in vitro. When tested in mice with induced breast cancer, carnosine proved to be non-toxic to healthy cells and exhibited chemopreventive activity by reducing tumor growth. Some evidence has also been reported at the clinical level. A randomized phase III prospective placebo-controlled trial showed the ability of Zn–carnosine to prevent dysphagia in breast cancer patients undergoing adjuvant radiotherapy. Despite this evidence, more preclinical and clinical studies are needed to better understand carnosine’s anti-tumoral activity, especially in the context of breast cancer.
... Increased intake of the amino acid βalanine via meat ingestion or supplementation has been shown to increase the carnosine content in the skeletal muscle by ~50%-100% (Rezende et al., 2020;Saunders et al., 2017). Skeletal muscle is the tissue where carnosine is most abundant, representing 99% of the total bodily pool of carnosine (Boldyrev et al., 2013). The biological importance of carnosine resides on its properties and purported functions, which include H + buffering (Harris et al., 2006;Smith, 1938), regulation of Ca 2+ transients and sensitivity (Dutka et al., 2012), protection against glycation and carbonylation, and detoxification of reactive aldehydes (Carvalho et al., 2018). ...
... While anserine is highly expressed in the skeletal and cardiac muscles of several species of mammals and avians (Christman, 1976;Dolan et al., 2018;Everaert et al., 2013), several studies reported that anserine is not present in human striated muscles (Boldyrev et al., 2013;Christman, 1976;Mannion et al., 1992). Likewise, the gene encoding the anserine-forming enzyme, initially characterized in chickens as histamine-Nmethyltransferase-like protein (HNMT-like) has been reported not to be part of mammalian genomes (Drozak et al., 2013). ...
... In a scenario of low expression and catalytic efficiency of the sole anserine-forming enzyme where carnosine formation is the main substrate for anserine synthesis, it seems natural that anserine levels will necessarily fall far below carnosine levels. Finally, the fact that carnosine content in the cardiac muscle is lower than in the skeletal muscle (Boldyrev et al., 2013;Creighton et al., 2022) and that the same pattern was observed for anserine in this study seems reinforce the idea that carnosine levels have a strong influence on anserine levels. ...
We evaluated whether anserine, a methylated analog of the dipeptide carnosine, is present in the cardiac and skeletal muscles of humans and whether the CARNMT1 gene, which encodes the anserine synthesizing enzyme carnosine‐N‐methyltransferase, is expressed in human skeletal muscle. We found that anserine is present at low concentrations (low micromolar range) in both cardiac and skeletal muscles, and that anserine content in skeletal muscle is ~15 times higher than in cardiac muscle (cardiac muscle: 10.1 ± 13.4 μmol·kg ⁻¹ of dry muscle, n = 12; skeletal muscle: 158.1 ± 68.5 μmol·kg ⁻¹ of dry muscle, n = 11, p < 0.0001). Anserine content in the heart was highly variable between individuals, ranging from 1.4 to 45.4 μmol·kg ⁻¹ of dry muscle, but anserine content was not associated with sex, age, or body mass. We also showed that CARNMT1 gene is poorly expressed in skeletal muscle ( n = 10). This is the first study to demonstrate that anserine is present in the ventricle of the human heart. The presence of anserine in human heart and the confirmation of its expression in human skeletal muscle open new avenues of investigation on the specific and differential physiological functions of histidine dipeptides in striated muscles.
... Since the initial discovery in 1900 by Vladimir Gulevich, 1 carnosine and the other HCDs have been linked to various physiological functions, mostly serving to preserve redox status and cellular homeostasis (for a full overview, see Ref. [2]). The most relevant biochemical properties for their functions relate to proton buffering, metal chelation, and antioxidant capacity, which further translates to protection against advanced glycation and lipoxidation end products. ...
... It is unclear what causes these low HCD levels in the heart, but a low turnover rate or a role for carnosinase activity are unlikely given the low abundance of CARNS1 and the questionable role of tissue CNDP2 for carnosine homeostasis. 2,41,42 Nevertheless, HCDs are thought to play a crucial role in cardiac function and recovery from injury. 12,43 For instance, isolated cardiac myocytes from Carns1-transgenic hearts were protected against hypoxia reoxygenation injury, 44 while Carns1-KO rats have impaired cardiac contractility accompanied by reduced Ca 2+ peaks and slowed Ca 2+ removal. ...
... 22 This issue remains largely unclear in humans, in which high activity of the CN1 enzyme quickly degrades circulating carnosine. 2 It has long been suggested that circulating HCDs are extremely low or absent in human plasma, 48-50 although more recent reports already detected carnosine. 51, 52 We now demonstrate that N-acetylcarnosine is the most stable carnosine analog in plasma, indicating that acetylation of the βalanine residue protects against the hydrolyzing activity of CN1, as has been previously suggested. ...
Aim:
Histidine-containing dipeptides (HCDs) are pleiotropic homeostatic molecules with potent antioxidative and carbonyl quenching properties linked to various inflammatory, metabolic, and neurological diseases, as well as exercise performance. However, the distribution and metabolism of HCDs across tissues and species are still unclear.
Methods:
Using a sensitive UHPLC-MS/MS approach and an optimized quantification method, we performed a systematic and extensive profiling of HCDs in the mouse, rat, and human body (in n = 26, n = 25, and n = 19 tissues, respectively).
Results:
Our data show that tissue HCD levels are uniquely produced by carnosine synthase (CARNS1), an enzyme that was preferentially expressed by fast-twitch skeletal muscle fibres and brain oligodendrocytes. Cardiac HCD levels are remarkably low compared to other excitable tissues. Carnosine is unstable in human plasma, but is preferentially transported within red blood cells in humans but not rodents. The low abundant carnosine analogue N-acetylcarnosine is the most stable plasma HCD, and is enriched in human skeletal muscles. Here, N-acetylcarnosine is continuously secreted into the circulation, which is further induced by acute exercise in a myokine-like fashion.
Conclusion:
Collectively, we provide a novel basis to unravel tissue-specific, paracrine, and endocrine roles of HCDs in human health and disease.
... During the search for a protective substance against Zn 2+ -induced neurotoxicity, we found that carnosine (β-alanylhistidine) exhibited a marked inhibitory effect on Zn 2+ -induced neurotoxicity and proposed that it is a candidate drug for the treatment of VD [16]. Carnosine is an endogenous dipeptide with various useful properties such as antioxidant, antiglycation and anti-cross-linking ( Figure 1) [17,18]. Carnosine accumulates abundantly in the skeletal muscle and olfactory bulb. ...
... Carnosine is a natural dipeptide composed of β-alanine and L-histidine (His). Carnosine and its analogues (anserine [1-methylcarnosine] and homocarnosine) are present in most vertebrate tissues, including those of birds, fish, and mammals including humans [17,18]. In particular, carnosine is present in high levels in animals and fish that exercise frequently, such as horses, chickens, bonitos, and whales. ...
... In addition, carnosine possesses various functions, such as anti-oxidation, anti-glycation, anticross-linking, and metal chelation, which mediate its beneficial effects in vivo [18]. Carnosine scavenges both reactive oxygen-and nitrogen-containing unpaired electrons and inhibits lipid oxidation through a combination of free radical scavenging and metal chelation. ...
Synaptic zinc ions (Zn2+) play an important role in the development of vascular dementia (VD) and Parkinson’s disease (PD). In this article, based on our study and many others, we review the mo-lecular pathways by which Zn2+ causes neurotoxicity. Zn2+ influences calcium homeostasis, energy production pathway, production of reactive oxygen species, endoplasmic reticulum stress pathway, and activated protein kinase/c-Jun amino terminal kinase (SAPK/JNK) pathway and consequently exerts neurotoxicity. Furthermore, we searched various crops for substances that protect neurones from neurotoxicity caused by Zn2+ and clarified that carnosine (β-alanylhistidine) may be a therapeutic drug for VD and PD. Here, we also review the molecular mechanisms underlying the role of carnosine as an endogenous protector and its protective effect against Zn2+-induced cyto-toxicity and discuss prospects for future neurodegenerative diseases therapeutic applications of this dipeptide.
... Carnosine is an endogenous dipeptide (β-Ala and L-His) synthesized mainly in muscle (Boldyrev et al., 2013). The increase of the carnosine concentrations in the serum of dairy cow during the postpartum period was also shown in other studies Zhang et al., 2017b;Ghaffari et al., 2019), and was paralleled by a decrease in His and an increase of β-Ala. ...
... The increase of the carnosine concentrations in the serum of dairy cow during the postpartum period was also shown in other studies Zhang et al., 2017b;Ghaffari et al., 2019), and was paralleled by a decrease in His and an increase of β-Ala. Carnosine is degraded to the dipeptide anserine, which in turn is metabolized to 1-Met-His and β-Ala (Boldyrev et al., 2013). The 1-Met-His was one of the highly regulated AA-related metabolites by the body, showing a decrease after calving (wk +5, +10, and +15), which might indicate reduced degradation of carnosine and anserine. ...
The objective of this study was to characterize changes in the serum metabolome and various indicators of oxidative balance in dairy cows starting 2 wk before dry-off and continuing until wk 16 of lactation. Twelve Holstein dairy cows [body weight (BW) 745 ± 71 kg, body condition score 3.43 ± 0.66; mean ± SD] were housed in a tie-stall barn from 10 wk before to 16 wk after parturition. Cows were dried off 6 wk before the expected calving date (mean dry period length = 42 d). From 8 wk before calving to 16 wk after calving, blood samples were taken weekly to study redox metabolism by determining antioxidant capacity, measured as the ferric-reducing ability of plasma, reactive oxidative metabolites, oxidative stress index, oxidative damage of lipids, measured as thiobarbituric acid reactive substances, and glutathione peroxidase activity. According to these results, dairy cows had the lowest serum antioxidant capacity and greater levels of oxidative stress during the dry-off period and the early postpartum period. For metabolomics, a subset of serum samples including wk −7 (before dry-off), −5 (after dry-off), −1, 1, 5, 10, and 15 relative to calving were used. A targeted metabolomics approach was performed by liquid chromatography and flow injection with electrospray ionization triple quadrupole mass spectrometry using the MxP® Quant 500 kit. A total of 240 metabolites in serum were used in the final data analysis. Principal component analysis revealed a clear separation by days of sampling, indicating a remarkable shift in metabolic phenotype between the dry period and late and early lactation. Changes in many non-lipid metabolites associated with one-carbon metabolism, the tricarboxylic acid cycle, the urea cycle, and AA catabolism were observed in the study, with changes in AA serum concentrations likely related to factors such as energy and nitrogen balance, digestive efficiency, and changing diets. The study confirmed an extensive remodeling of the serum lipidome in peripartum dairy cows, highlighting the importance of changes in acylcarnitine (AcylCN), phosphatidylcholines (PC), and triacylglycerols (TG), as they play a crucial role in lipid metabolism. Results showed that short-chain AcylCN increased after dry-off and decreased thereafter, whereas lipid-derived AcylCN increased around parturition, suggesting that more fatty acids could enter mitochondria. Phospholipids and sphingolipids in serum showed changes during lactation. In particular, concentrations of sphingomyelins (SM), PC, and LysoPC decreased around calving but increased in mid- and late lactation. In contrast, concentrations of TG remained consistently low after parturition. The serum concentrations of bile acids fluctuated during the dry period and lactation, with glycocholic acid, cholic acid, glycodeoxycholic acid, and taurocholic acid showing the greatest concentrations. These changes are likely due to the interplay of diet, liver function, and the ability of the gut microbiota to convert primary to secondary bile acids. Overall, these descriptive results may aid in hypothesis generation, and the design and interpretation of future metabolite-based studies in dairy cows. Furthermore, they contribute to our understanding of the physiological ranges in serum metabolites relative to the lactation cycle of the dairy cow.
... Carnosine N-methyltransferase 1 (CARNMT1) methylates the dipeptide carnosine (Ala-His) also at the N1 position to produce anserine (Drozak et al. 2015). As its name would suggest, carnosine and its derivatives are highly abundant in skeletal muscle, where they function to maintain homeostasis by buffering pH, chelating metal ions, and acting as antioxidants (for review, see Boldyrev et al. 2013). In addition to carnosine, CARNMT1 can methylate multiple dipeptide and tripeptide sequences, suggesting that it may possess a broader target specificity (Drozak et al. 2015). ...
... Intriguingly, carnosine but not anserine inhibited CARNMT1-dependent protein methylation, suggesting competition between substrates for limiting methyltransferase activity. Carnosine and anserine have been proposed to have exocrine functions when released from muscle during exercise (Boldyrev et al. 2013). CARNMT1 is the first known methyltransferase with dual substrate specificity, modifying both a small-molecule dipeptide and protein targets. ...
Specialized enzymes add methyl groups to the nitrogens of the amino acid histidine, altering the chemical properties of its imidazole ring and, in turn, the function of the modified (poly)peptide. In this issue of Genes & Development , Shimazu and colleagues (pp. XXX–XXX) make the remarkable discovery that CARNMT1 acts as a dual-specificity histidine methyltransferase, modifying both the small-molecule dipeptide carnosine and a set of proteins, predominantly within RNA-binding C3H zinc finger (C3H ZF) motifs. As a result, CARNMT1 modulates the activity of its protein targets to affect RNA processing and metabolism, ultimately contributing an essential function during mammalian development.
... It can exert cardiovascular and metabolic protection effects by maintaining the integrity of cell membranes, lowering blood pressure, and limiting ischemia-reperfusion injury [11][12][13]. Carnosine and anserine are dipeptides with physiological significance in ameliorating the development of MetS due to their antioxidant capacity, anti-lipidemic, and anti-glycation actions [14,15]. Creatine, a metabolite of amino acids, is found to involve antioxidative and anti-apoptotic reactions, and modulate energy metabolism in the excitable tissues (i.e., brain and skeletal muscle) [16,17]. ...
... It is a double-blind randomized pilot trial to test the effect of carnosine supplementation on glucose metabolism. Then, six references were review articles [14,[25][26][27][28][29] and the other three references were mice-based basic research, including the role of taurine supplementation on glucose homeostasis and islet function [30], the treatment effect of carnosine on diabetes and diabetic nephropathy [31], and the mechanisms of carnosine ameliorating dyslipidemia, hypertension, and renal function [32]. ...
Red meat and animal-sourced protein are often disparaged as risk factors for developing metabolic syndrome, while emerging research has shown the beneficial effects of dietary taurine, creatine, carnosine, and anserine which are all exclusively abundant in red meat. Thus, it is imperative to highlight the available evidence to help promote red meat as part of a well-balanced diet to optimize human health. In this study, a bibliometric analysis was conducted to investigate the current research status of dietary taurine, creatine, carnosine, and anserine with metabolic syndrome, identify research hotspots, and delineate developmental trends by utilizing the visualization software CiteSpace. A total of 1094 publications were retrieved via the Web of Science Core Collection from 1992 to 2022. There exists a gradual increase in the number of publications on this topic, but there is still much room for research papers to rise. The United States has participated in the most studies, followed by China and Japan. The University of Sao Paulo was the research institute contributing the most; Kyung Ja Chang and Sanya Roysommuti have been identified as the most prolific authors. The analysis of keywords reveals that obesity, lipid profiles, blood pressure, and glucose metabolism, as well as ergogenic aid and growth promoter have been the research hotspots. Inflammation and diabetic nephropathy will likely be frontiers of future research related to dietary taurine, creatine, carnosine, and anserine. Overall, this paper may provide insights for researchers to further delve into this field and enlist the greater community to re-evaluate the health effects of red meat.
... 23 CN1 is the first and major hydrolyzer for histidine-containing dipeptides in serum, whereas the remaining is continuously degraded when they permeate into tissue. 24,25 Although CAR and ANS are major substrates, CN1 can also digest CAR analogues such as OPH and H-CAR 10,26 ( Figure 1B). Research on OPH and H-CAR is less extensive because such chemicals do not mainly contribute to human diet. ...
Carnosine (CAR), anserine (ANS), homocarnosine (H-CAR), and ophidine (OPH) are histidine-containing dipeptides that show a wide range of therapeutic properties. With their potential physiological effects, these bioactive dipeptides are considered as bioactive food components. However, such dipeptides display low stability due to their rapid degradation by human serum carnosinase 1 (CN1). A dimeric CN1 hydrolyzes such histidine-containing compounds with different degrees of reactivities. A selective CN inhibitor, carnostatine (CARN), was reported to effectively inhibit CN’s activity. To date, the binding mechanisms of CAR and ANS have been recently reported, while no clear information about H-CAR, OPH, and CARN binding is available. Thus, in this work, molecular dynamics simulations were employed to elucidate the binding mechanism of H-CAR, OPH, and CARN. Among all, the amine end and imidazole ring are the main players for trapping all of the ligands in a pocket. OPH shows the poorest binding affinity, while CARN displays the tightest binding. Such firm binding is due to the longer amine chain and the additional hydroxyl (–OH) group of CARN. H-CAR and CARN are analogous, but the absence of the –OH moiety in H-CAR significantly enhances its mobility, resulting in the reduction in binding affinity. For OPH which is an ANS analogue, the methylated imidazole ring destroys the OPH–CN1 interaction network at this region, consequentially leading to the poor binding ability. An insight into how CN recognizes and binds its substrates obtained here will be useful for designing an effective strategy to prolong the lifetime of CAR and its analogues after ingestion.
... As research accumulated on the use of β-alanine as an ergogenic aid, subsequent metaanalyses have indicated that β-alanine is efficacious at increasing exercise capacity [2]. In addition, understanding of the physiological role that elevations in carnosine have in tissue also resulted in the hypothesis that β-alanine supplementation may have a role as an antioxidant [7]. In studies examining the efficacy of β-alanine supplementation on soldiers in special operation units, the ability to improve physical function was observed, but the investigations also indicated that those soldiers that supplemented with β-alanine also experienced significant improvements in cognitive function during periods of high stress (e.g., performing mathematical equations on a firing line and being able to expeditiously ...
This study investigated 10 weeks of β-alanine (BA) supplementation on changes in cognitive function, mood, and physical performance in 100 older adults (70.6 ± 8.7 y). Participants were randomized into a BA (2.4 g·d-1) or placebo (PL) group. Testing occurred prior to supplementation (PRE), at the midpoint (MID), and at week-10 (POST). Participants completed cognitive function assessments, including the Montreal cognitive assessment (MOCA) and the Stroop pattern recognition test, at each testing session. Behavioral questionnaires [i.e., the profile of mood states, geriatric depression scale (GDS), and geriatric anxiety scale (GAS)] and physical function assessments (grip strength and timed sit-to-stand) were also conducted. No difference between groups was noted in MoCA scores (p = 0.19). However, when examining participants whose MOCA scores at PRE were at or below normal (i.e., ≤26), participants in BA experienced significant improvements in MOCA scores at MID (13.6%, p = 0.009) and POST (11.8%, p = 0.016), compared to PL. No differences were noted in mood scores, GAS, or any of the physical performance measures. A significant decrease was observed in the GDS for participants consuming BA but not in PL. Results suggested that BA supplementation can improve cognitive function in older adults whose cognitive function at baseline was at or below normal and possibly reduce depression scores.
... Our results are consistent with those of another study indicating that overexpression of CNDP1, the metabolic enzyme of carnosine, is associated with a risk for poor diabetes control (and a high risk for T2DM and DKD). CNDP2 is another carnosinase that mainly hydrolyzes other HDP substrates (homocarnosine and anserine) under nonphysiological conditions (Boldyrev et al. 2013). In our study, homocarnosine was elevated in patients with DKD due to attenuated activation of the downstream enzyme CNDP2; homocarnosine is endogenously synthesized in skeletal muscle from histidine and γ-aminobutyric acid and its concentration is barely influenced by a low dietary protein intake. ...
Diabetic kidney disease (DKD), a highly prevalent complication of diabetes mellitus, is a major cause of mortality in patients. However, identifying circulatory markers to diagnose DKD requires a thorough understanding of the metabolic mechanisms of DKD. In this study, we performed ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to reveal altered metabolic profiles of amino acids (AAs) in patients with DKD. We found decreased plasma levels of histidine and valine, increased urine levels of proline, decreased urine levels of histidine and valine, and increased saliva levels of arginine in patients with DKD compared with the levels in patients with type 2 diabetes mellitus (T2DM) and in healthy controls. Our analyses of the key metabolites and metabolic enzymes involved in histidine and valine metabolism indicated that the AAs level alterations may be due to enhanced carnosine hydrolysis, decreased degradation of homocarnosine and anserine, enhanced histidine methylation, and systemic enhancement of valine metabolism in patients with DKD. Notably, we generated a distinct diagnostic model with an AUC of 0.957 and an accuracy up to 92.2% on the basis of the AA profiles in plasma, urine and saliva differing in patients with DKD using logistic regression and receiver operating characteristic analyses. In conclusion, our results suggest that altered AA metabolic profiles are associated with the progression of DKD. Our DKD diagnostic model on the basis of AA levels in plasma, urine, and saliva may provide a theoretical basis for innovative strategies to diagnose DKD that may replace cumbersome kidney biopsies.
... Proteins or polypeptides are digested by proteases, such as dipeptidyl peptidase (Tachi et al. 1992), or single amino acids are connected by ligases to form dipeptides (Tabata et al. 2005). Many dipeptides show a variety of biological activities, such as angiotensin-converting enzyme (ACE) inhibition (Val-Trp) (Saito et al. 1994), antihypertensive activity (Tyr-Tyr) (Shobako et al. 2018), antioxidant activity (Boldyrev et al. 2013;Guiotto et al. 2005;Kohen et al. 1988), quenching toxic electrophiles (β-Ala-His, carnosine) (Takama et al. 2020;Tatsuno et al. 2018), anti-atherosclerotic activity (Trp-His) , memory impairment activity (Tyr-Pro) (Tanaka et al. 2020), an analgesic effect (Tyr-Arg, kyotorphin) (Takagi et al. 1979), and stimulation of noradrenergic turnover (Ser-Tyr) (Ichinose et al. 2015). Some bioactive peptides, including dipeptides, are widely found in food, including ACE-inhibitory and antioxidant peptides found in microalgae ) and in donkey milk (Zenezini Chiozzi et al. 2016). ...
In this study, a validated analytical method based on liquid chromatography/electrospray ionization-selected reaction monitoring/mass spectrometry (LC/ESI-SRM/MS) was developed for dipeptides in a functional food, fermented brown rice and rice bran with Aspergillus oryzae (FBRA). The aim of this study was to screen and quantify dipeptides in the water-soluble fraction of FBRA. There are few studies focusing on dipeptides in FBRA, even though FBRA is expected to contain bioactive peptides: FBRA or its aqueous extract has shown variety of biological activities. An anti-hypertensive dipeptide was found in similar rice bran products digested by thermolysin. Dipeptides are the smallest class of peptides, and many show a variety of biological activities. Some bioactive peptides are widely found in fermented foods. However, because dipeptides are generally too polar to be retained on versatile LC columns, such as octadecylsilyl columns, dipeptides have been often overlooked and not quantified because of the analytical difficulties. The LC was performed using a porous graphitic carbon column with the mobile phases of 0.1% formic acid/0.1% trifluoroacetic acid/1% tetrahydrofuran in water and acetonitrile. The stable isotope-labeled internal standards and SRM for dipeptides made it possible to develop a validated method. Five dipeptides were identified and quantified in FBRA in much higher concentrations than related materials (malted brown rice, rice bran, brown rice, and white rice) as follows: Ile-Arg, 82.1 µg/g; Ala-Phe, 27.8 µg/g; Ala-Tyr, 31.6 µg/g; Val-Phe, 46.3 µg/g; and Ile-Tyr, 49.9 µg/g. This method was simple and robust and would be applicable for other functional foods.
Graphical Abstract
... This bacterial setting reflects alterations at the level of the faecal metabolomic profile, with a marked reduction in nicotinic acid, carnosine, succinate, and niacinamide found among DR patients as compared to controls [107]. Of note, mitochondrial function, inflammatory regulation, and antioxidant defences greatly rely on these metabolites [108,109]. GM alterations were also observed when comparing diabetic patients with and without DR. In the latter case, decreased levels of Veionella and Bacillus were reported in favour of an increase in Prevotella [107], which has a pro-inflammatory potential [110]. ...
The human microbiota refers to a large variety of microorganisms (bacteria, viruses, and fungi) that live in different human body sites, including the gut, oral cavity, skin, and eyes. In particular, the presence of an ocular surface microbiota with a crucial role in maintaining ocular surface homeostasis by preventing colonization from pathogen species has been recently demonstrated. Moreover, recent studies underline a potential association between gut microbiota (GM) and ocular health. In this respect, some evidence supports the existence of a gut–eye axis involved in the pathogenesis of several ocular diseases, including age-related macular degeneration, uveitis, diabetic retinopathy, dry eye, and glaucoma. Therefore, understanding the link between the GM and these ocular disorders might be useful for the development of new therapeutic approaches, such as probiotics, prebiotics, symbiotics, or faecal microbiota transplantation through which the GM could be modulated, thus allowing better management of these diseases.
... Overall, the conjugate shows a synergic antioxidant effect comparable to that displayed by its moieties, the ability of which to reduce ROS levels has previously been reported for Car [148,149] and Hy [150] in both in vitro and in vivo assays. Furthermore, despite the low metal concentrations present in the culture medium, Cu 2+ 's interaction with HyCar, Car, and Hy drives the antioxidant effect in a way that recalls the different metal affinities of Car [151] and Hy [152]. ...
A series of copper(II) complexes with the formula [Cu2+Hy(x)Car%] varying the molecular weight (MW) of Hyaluronic acid (Hy, x = 200 or 700 kDa) conjugated with carnosine (Car) present at different loading were synthesized and characterized via different spectroscopic techniques. The metal complexes behaved as Cu, Zn-superoxide dismutase (SOD1) mimics and showed some of the most efficient reaction rate values produced using a synthetic and water-soluble copper(II)-based SOD mimic reported to date. The increase in the percentage of Car moieties parallels the enhancement of the I50 value determined via the indirect method of Fridovich. The presence of the non-functionalized Hy OH groups favors the scavenger activity of the copper(II) complexes with HyCar, recalling similar behavior previously found for the copper(II) complexes with Car conjugated using β-cyclodextrin or trehalose. In keeping with the new abilities of SOD1 to activate protective agents against oxidative stress in rheumatoid arthritis and osteoarthritis diseases, Cu2+ interaction with HyCar promotes the nuclear translocation of erythroid 2-related factor that regulates the expressions of target genes, including Heme-Oxigenase-1, thus stimulating an antioxidant response in osteoblasts subjected to an inflammatory/oxidative insult.
... Histidine is an essential amino acid which is required for protein synthesis. It is a precursor of carnosine (b-alanyl-L-histidine) which is found in high amounts in muscle tissues [41]. In summary, all metabolites which were found to be associated with muscle mass and/or muscle decline in the present study, have previously been related to muscle metabolism in preclinical and some clinical studies and a physiological rationale for each of the observed correlations is plausible. ...
... Meanwhile, methionylleucine is an incomplete breakdown products of protein catabolism. It has a role in cell-signaling effects [43]. D-lysopine is an amino acid derivative obtained from the L-lysine derivative. ...
Beef sausage (BS) is one of the most favored meat products due to its nutrition and good taste. However, for economic purposes, BS is often adulterated with pork by unethical players. Pork consumption is strictly prohibited for religions including Islam and Judaism. Therefore, advanced detection methods are highly required to warrant the halal authenticity of BS. This research aimed to develop a liquid chromatography–high-resolution mass spectrometry (LC–HRMS) method to determine the halal authenticity of BS using an untargeted metabolomics approach. LC–HRMS was capable of detecting various metabolites in BS and BS containing pork. The presence of pork in BS could be differentiated using principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) with high accuracy. PLS-DA perfectly classified authentic BS and BS containing pork in all concentration levels of pork with R2X = (0.821), R2Y(= 0.984), and Q2 = (0.795). The level of pork in BS was successfully predicted through partial least squares (PLS) and orthogonal PLS (OPLS) chemometrics. Both models gave high R2 (>0.99) actual and predicted values as well as few errors, indicating good accuracy and precision. Identification of discriminating metabolites’ potential as biomarker candidates through variable importance for projections (VIP) value revealed metabolites of 2-arachidonyl-sn-glycero-3-phosphoethanolamine, 3-hydroxyoctanoylcarnitine, 8Z,11Z,14Z-eicosatrienoic acid, D-(+)-galactose, oleamide, 3-hydroxyhexadecanoylcarnitine, arachidonic acid, and α-eleostearic acid as good indicators to detect pork. It can be concluded that LC–HRMS metabolomics combined with PCA, PLS-DA, PLS, and OPLS was successfully used to detect pork adulteration in beef sausages. The results imply that LC–HRMS untargeted metabolomics in combination with chemometrics is a promising alternative as an analytical technique to detect pork in sausage products. Further analysis of larger samples is required to warrant the reproducibility.
... Carnosine (beta-alanyl-L-histidine) is a histidine-containing dipeptide made up of the amino acids β-alanine and L-histidine. It is abundant in skeletal and cardiac muscles, liver tissues, and regions of the central nervous system [29], and is known to be important for maintaining redox homeostasis due to its antioxidant activity [30]. For these reasons, carnosine is recognized as a protective factor in muscle cells, nerve cells, and ECs [31][32][33]. ...
Background: Increasing evidence suggests that hemodynamic disturbed flow induces endothelial dysfunction via a complex biological process so-called endothelial to mesenchymal transition (EndoMT). Recently, DNA methyltransferases (DNMTs) was reported as a key molecular mediator to promote EndoMT. Our understanding of how DNMTs, particularly the maintenance DNMTs, DNMT1, coordinate EndoMT is still lacking. Methods: A parallel-plate flow apparatus and perfusion devices were used to apply fluid with endothelial protective pulsatile shear (PS, to mimic the laminar flow) or harmful oscillatory shear (OS, to mimic the disturbed flow) to cultured endothelial cells (ECs). Endothelial lineage tracing mice and conditional EC Dnmt1 knockout mice were subjected to a surgery of carotid partial ligation to generate the flow-accelerated atherogenesis models. Western blotting, quantitative RT-PCR, immunofluorescent staining, methylation-specific PCR, chromatin immunoprecipitation, endothelial functional assays, and assessments for neointimal formation and atherosclerosis were performed. Results: Inhibition of DNMTs with 5-aza-2'-deoxycytidine (5-Aza) suppressed the disturbed flow/OS-induced EndoMT, both in cultured cells and the endothelial lineage tracing mice. 5-Aza also ameliorated the downregulation of aldehyde dehydrogenases (ALDHs) and β-alanine biosynthesis caused by disturbed flow/OS. Knockdown of the ALDH family proteins, ALDH2, ALDH3A1, and ALDH6A1, showed an EndoMT-induction effect as OS. Supplementation of cells with the functional metabolites of β-alanine, carnosine and acetyl-CoA (acetate), reversed EndoMT, likely via inhibiting the phosphorylation of Smad2/3. Endothelial-specific knockout of Dnmt1 protected the vasculature from disturbed flow-induced remodeling and atherosclerosis. Conclusions: Endothelial DNMT1 acts as one of the key epigenetic factors to mediate the hemodynamically regulated EndoMT at least through repressing the expression of ALDH2, ALDH3A1, and ALDH6A1. Supplementation with carnosine and acetate may have a great potential in the prevention and treatment of atherosclerosis.
... Carnosine (ß-alanyl-L-histidine), an over-the-counter food supplement, belongs to the group of naturally occurring histidine-containing dipeptides. In mammals and humans, carnosine is one of the most abundant dipeptides with the highest concentration in muscle (Boldyrev et al. 2013). In experimental settings, carnosine has been shown to exert a variety of cytoprotective functions, such as anti-glycation and antioxidant effects (Hou 2003), HNE quenching (Aldini et al. 2021), methylglyoxal polymerisation (Brings et al. 2017;Weigand et al. 2018) and contributes to intramuscular buffer capacity (de Brandt et al. 2022). ...
Carnosine (β-Alanyl-L-Histidine) is a naturally occurring endogenous dipeptide and over-the-counter dietary supplement with a multimodal mechanism of action. The use of carnosine and its analogues in is as diverse as its mode of action and application. Carnosine’s ready availability and protective properties make it an interesting candidate for clinical use. We have now examined the mode of use in registered clinical studies. In a cross-sectional study, we evaluated the status of clinical studies on carnosine and carnosine analogues. We searched all 16 primary clinical trials registries listed in the WHO Clinical Trials Registry. Registered studies to published studies were identified and the ratio of published/unpublished studies as well as the time to publication and thematic focus were evaluated. The 16 selected registries listed 70 studies on carnosine, of which 34 have been completed and 25 have been published to date, with an average time to publication of 28 months. Carnosine/carnosine analogues were used as dietary supplements in 56% of the studies. Twelve studies were clinical trials in healthy volunteers that focused on dietary changes and underlying physiology. The other 22 studies deal with various clinical pictures, in particular metabolic and psychological disorders. This structured evaluation shows that the applications of carnosine are very versatile, and the registration in one of the clinical registries and the timely publication would facilitate the planning of further studies.
... In our study, we found decreased plasma levels of histidine and valine in patients with DKD, these results are consistent with our previous ndings ( Our results are consistent with those of another study indicating that overexpression of CNDP1, the metabolic enzyme of carnosine, is associated with a the risk for poor diabetes control (and a high risk for T2DM and DKD). CNDP2 is another carnosinase that mainly hydrolyzes other HDP substrates (homocarnosine and anserine) under nonphysiological conditions (Boldyrev et al., 2013). In our study, homocarnosine was elevated in patients with DKD due to attenuated activation of the downstream enzyme CNDP2; homocarnosine is endogenously synthesized in skeletal muscle from histidine and γ-aminobutyric acid and its concentration is barely in uenced by a low dietary protein intake. ...
Diabetic kidney disease (DKD), a highly prevalent complication of diabetes mellitus, is a major cause of mortality in patients. However, identifying circulatory markers to diagnose DKD requires a thorough understanding of the metabolic mechanisms of DKD. In this study, we performed ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to reveal altered metabolic profiles of amino acids (AAs) in patients with DKD. We found decreased plasma levels of histidine and valine, increased urine levels of proline, decreased urine levels of histidine and valine, and increased saliva levels of arginine in patients with DKD compared with the levels in patients with type 2 diabetes mellitus (T2DM) and in healthy controls. Our analyses of the key metabolites and metabolic enzymes involved in histidine and valine metabolism indicated that the AAs level alterations may be due to enhanced carnosine hydrolysis, decreased degradation of homocarnosine and anserine, enhanced histidine methylation, and systemic enhancement of valine metabolism in patients with DKD. Notably, we generated a distinct diagnostic model with an AUC of 0.957 and an accuracy up to 92.2% on the basis of the AA profiles in plasma, urine and saliva differing in patients with DKD using logistic regression and receiver operating characteristic analyses. In conclusion, our results suggest that altered AA metabolic profiles are associated with the progression of DKD. Our DKD diagnostic model on the basis of AA levels in plasma, urine, and saliva may provide a theoretical basis for innovative strategies to diagnose DKD that may replace cumbersome kidney biopsies.
... Можно полагать, что новое вещество, созданное на основе двух компонентов (карнозина и пиррола), с учётом биологических свойств веществпрекурсоров, может стать новым перспективным соединением. Цитопротекторная эффективность гистидин-содержащего дипептида карнозина, обусловленная его широким спектром биологического действия, включая антиоксидантное, представлена в различных экспериментальных моделях паркинсонизма и ишемии головного мозга, а также в пилотных УДК 615.033.1 клинико-биохимических исследования [1,2]. Однако значимым фактором, лимитирующим внедрение карнозина в клиническую медицину в виде лекарственной формы, является его быстрый гидролиз в кровяном русле под действием специфического ферментасывороточной карнозиназы. ...
The experimental study of the pharmacokinetic characteristics of a new pyrrole derivative of carnosine, pyrrolylcarnosine, was carried out. Based on the results of the experiment, the basic pharmacokinetic parameters of the drug are expected. The tissues and organs bioavailability was studied. The tropism of pyrrolylcarnosine to the organs of elimination and the ability of pyrrolylcarnosine to penetrate into the heart muscle tissue were shown.
... Numerous studies show that carnosine concentrations can be increased through supplementation of β-alanine alone, increasing its concentrations in skeletal muscle, cardiac and brain tissues. [124][125][126] Research has identified that carnosine has several different biological properties that have interplay on reducing AGEs concentration including hypoglycemic, antioxidant, anti-inflammatory, and direct AGEs reducing capacity. 127 It has been successfully tested as an antiglycating agent and its role in delaying senile cataracts. ...
The accumulation of Advanced Glycation end products (AGEs) in the human body is an unavoidable part of the aging process in humans. Extensive research has linked AGEs to chronic disease and as a likely player in many of the changes seen during aging. AGEs are formed both endogenously and exogenously. AGEs accumulate in all tissues and body fluids and interact through a specific signal transduction receptor on the cell called a RAGE (Receptor for Advanced Glycation End Products). Pathologically, AGEs produce reactive oxygen species (ROS), reactive nitrogen species (RNS), oxidative stress, and inflammation. This leads to protein alterations causing both functional and structural changes, cellular dysfunction, apoptosis, and multiple tissue and organ injuries. High levels of AGEs in diet as well as in tissues and circulation are pathogenic to a wide range of diseases. Little is known about AGEs within the context of nutritional intervention. However, formation of both endogenous and exogenous AGEs can be targeted. There is a general lack of any robust clinical practice recommendations. In part 2 of this series, we will explore pathological influence, laboratory evaluation, and strategies for reduction of AGEs.
... Кроме того, приведённые в настоящем обзоре данные позволяют полагать, что для подавления атерогенеза и дисфункции эндотелия необходимо ингибировать не только (а, возможно, и не столько) накопление первичных продуктов (LOOH) в ЛНП, но и накопление вторичных продуктов свободнорадикального окислениянизкомолекулярных дикарбонилов. Уже имеются положительные примеры воздействия на интенсивность свободнорадикального окисления с использованием скэвинджеров дикарбонилов -бигуанидов [100,[111][112][113] и имидазол-содержащих пептидов [114,115]. В частности, использование бигуанидов значительно подавляло проявление окислительного и карбонильного стресса у больных сахарным диабетом без введения каких-либо антиоксидантов («квази-антиоксидантный эффект») [100]. Очевидно, что превентивная кардиология должна быть нацелена на предотвращение негативных последствий окислительной модификации ЛНП, поскольку модифицированные ЛНП, как показано в настоящем обзоре, играют важную роль в молекулярных механизмах атерогенеза и диабетогенеза. ...
The review presents evidence of the participation of low-density lipoproteins (LDL) modified by low molecular weight dicarbonyl compounds formed during freeradical oxidation of lipids (malondialdehyde) and carbohydrates in the development of endothelial dysfunction and atherosclerotic vascular lesions. The authors believe that it is they, and not oxidized (hydroperoxide-containing) LDL, that are the main factors of pathogenesis. The role of dicarbonyl-modified LDL in LOX-1 dependent induction of processes leading to the development of endothelial dysfunction is discussed. The results of studies proving that damage to the glycocalyx (a layer of macromolecules that prevent the development of endothelial dysfunction) covering the luminal surface of the endothelium is caused by hyperproduction of reactive oxygen species. Ways of pharmacological correction of free-radical oxidation processes are discussed, due to which inhibition of atherogenesis and diabetogenesis can be achieved.
... Alanine itself has no antioxidant effect, but it can synthesize carnosine in vivo. Carnosine has a significant scavenging effect on DPPH free radicals and has a positive effect on anti-skin aging (35). In addition, some studies have found that supplementation with alanine can enhance the antioxidant capacity of mice (36). ...
Astragalus membranaceus ( A. membranaceus ) is a homologous plant with high medicinal and edible value. Therefore, the extraction methods of Astragalus polysaccharide (APS) have attracted the attention of many research groups, but the yield of the active components is still not high. The aim of this study was to extract APS by a semi-bionic extraction method, optimize the extraction process, and evaluate the anti-aging activities of APS in vivo . The results showed that the APS yield was 18.23% when extracted by the semi-bionic extraction method. Anti-aging evaluation in rats showed that APS extracted by this method significantly decreased the malondialdehyde (MDA) content and increased superoxide dismutase (SOD) activity to cope with D-galactose-induced aging. Serum metabolomic analysis indicated that a total of 48 potential biomarkers showed significant differences, mainly involving 5 metabolic pathways. These altered metabolic pathways were mainly related to energy metabolism, amino acid metabolism, and lipid metabolism. These results indicated that the semi-bionic extraction method can effectively improve the yield of APS, and the extracted APS exhibited anti-aging activity in rats. Our study provided a novel and effective method to extract APS and indicated that APS can be used as functional food and natural medicine to delay aging and prevent its complications.
... This finding is consistent with the observed effect on promoting muscle strength and muscle mass. Carnosine (βalanyl-L-histidine) is an intramuscular dipeptide consisting of βalanine and L-histidine (49). Therefore, the changes in the ratio between the free amino acids (β-alanine and histidine) and the dipeptide carnosine can be an indicator of changes in muscle protein synthesis and degradation. ...
Background
Elevated inflammation and negative nutritional balance contribute to sarcopenia, a progressive loss of muscle mass, strength, and function. This study investigated the effect of energy supplementation and the combination of anti-inflammatory factor (eicosapentaenoic acid; EPA) and muscle-synthesis promotor (branched-chain amino acids; BCAA) on body composition, muscle, and inflammatory biomarkers in elderly with inadequate protein intake.
Methods
A randomized blinded placebo-controlled trial was conducted on 84 elderly with inadequate protein intake. The participants were randomly assigned into four groups receiving a complete nutrition drink; (1) control formula, (2) fortified with 2.2 g EPA, (3) with 2.2 g EPA and 5 g BCAA (2:1:1 of Leu: Ile: Val), and (4) with 2.2 g EPA plus 5g BCAA (4:1:1 of Leu: Ile: Val). Each subject consumed two sachets of the drink to gain 500 kcal/day and performed arm muscle exercises for 3 weeks. Body compositions and handgrip strength were measured using BIA and a dynamometer, respectively. Plasma EPA and BCAA levels were determined using LC-MS/MS to ensure compliance. Muscle protein biomarkers including histidine, β-alanine, and carnosine were measured using LC-MS/MS. Serum inflammatory (IL-6) and anti-inflammatory cytokines (IL-10) were measured by using ELISA.
Results
No symptoms and signs of adverse events were observed. The right arm muscle mass and handgrip strength were significantly increased after consuming a complete nutrition drink fortified with EPA + BCAA 2:1:1 and 4:1:1 of Leu: Ile: Val ( p < 0.05 and p < 0.01, respectively. Consistently, consuming such combinatory formula non-significantly elevated carnosine with reduced histidine, and increased IL-10 with decreased IL-6. All relevant intervention groups showed a significant increase in plasma levels of BCAA and EPA.
Conclusion
Consuming a complete nutrition drink fortified with 2.2g EPA and 5g BCAA 2:1:1 or 4:1:1 of Leu: Ile: Val for 3 weeks may increase right arm muscle mass and strength in elderly with inadequate protein intake. The tendency of increased dipeptide (carnosine)/decreased free amino acid (histidine) suggests a shift toward muscle protein synthesis. The trend of decreased inflammatory/increased anti-inflammatory cytokines suggests an anti-inflammatory effect. Future long-term studies are warranted to confirm the combinatory effect of BCAA and EPA in the prevention of sarcopenia.
Clinical trial registration
Thailand Clinical Trial Registry No. TCTR20230116005.
... The abundance of carnosine in skeletal muscle has stirred the scientific imagination and research over the past century. Extraordinary efforts were made in the last decade once it was established that the dietary intake of carnosine enhances its concentrations in skeletal muscles, the brain, and the heart [57]. The dietary intake of the carnosine precursor beta-alanine also augmented human muscle carnosine concentration and improved exercise capacity [58][59][60]. ...
Backyard poultry farming contributes to food security, nutrition, and the regular income of rural farmers in India. Their products have a niche market here and fetch higher prices than those of commercial poultry. Improved varieties are being developed to overcome the slow growth, late sexual maturity, and low production of indigenous breeds, while retaining their positive attributes. A comprehensive study was conducted to analyze the functional attributes of meat from the Jabalpur color (JBC), a colored, improved dual-purpose synthetic line, developed by Nanaji Deshmukh Veterinary Science University, Jabalpur, India. The birds were managed in a deep litter system under a backyard type of housing (night shelter and free range). Primal meat cuts (breast and thigh) of the male birds (n = 20/group) were evaluated at the age of marketing. The corresponding attributes were compared with the results obtained for commercial Cobb (400) broilers. The protein concentration of JBC breast (25.65 ± 0.39 g/100 g of tissue) and thigh (19.04 ± 0.23 g/100 g of tissue) meat was superior (p ≤ 0.05) to that of Cobb broilers. Established assays (in vitro) identified a better (p ≤ 0.05) antioxidation capacity in the JBC meat. High-performance liquid chromatography confirmed a considerable quantity of functional biomolecules (carnosine, anserine, and creatine) in the JBC breast and thigh meat extracts. The average carnosine concentration (mg/g of tissue) was 2.66 ± 0.09 and 1.11 ± 0.04 in the JBC breast and thigh meat, respectively. The mRNA expression was quantified by qRT-PCR for the carnosine-related genes: β-alanine transporter (SLC36A1), carnosine-synthesizing enzyme (CARNS1), and carnosine-degrading enzyme (CNDP2); this explained the comparable carnosine in the JBC and Cobb meat. Meat extracts from both genetic groups (JBC and Cobb) had high anti-glycation potential. Higher protein content and antioxidant capacity, along with the bioactive dipeptides in the JBC meat, herald exciting research opportunities for its use in improving the traditional backyard poultry farming system.
... Thus, we used AV metabolomics in legs, to systematically map the metabolite exchange of the leg in each condition (Extended Data Table 1). Of note, all thermogenic states (CC, AC and CL), regardless of muscle shivering, induce the release of carnosine and anserine ( Fig. 3a-d), which are histidine dipeptides with reported signaling functions 42 . Carnosine supplementation induces white adipose tissue browning in rats 43 and mitigates high-fat-diet-induced metabolic disorders 44 . ...
Adaptive thermogenesis by brown adipose tissue (BAT) dissipates calories as heat, making it an attractive anti-obesity target. Yet how BAT contributes to circulating metabolite exchange remains unclear. Here, we quantified metabolite exchange in BAT and skeletal muscle by arteriovenous metabolomics during cold exposure in fed male mice. This identified unexpected metabolites consumed, released and shared between organs. Quantitative analysis of tissue fluxes showed that glucose and lactate provide ~85% of carbon for adaptive thermogenesis and that cold and CL316,243 trigger markedly divergent fuel utilization profiles. In cold adaptation, BAT also dramatically increases nitrogen uptake by net consuming amino acids, except glutamine. Isotope tracing and functional studies suggest glutamine catabolism concurrent with synthesis via glutamine synthetase, which avoids ammonia buildup and boosts fuel oxidation. These data underscore the ability of BAT to function as a glucose and amino acid sink and provide a quantitative and comprehensive landscape of BAT fuel utilization to guide translational studies.
Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of morbidity and mortality in patients with prediabetes and type 2 diabetes mellitus (T2DM). Carnosine has been suggested as a potential approach to reduce ASCVD risk factors. However, there is a paucity of human data. Hence, we performed a 14-week double-blind randomized placebo-controlled trial to determine whether carnosine compared with placebo improves vascular and metabolic outcomes in individuals with prediabetes and T2DM. In total, 49 patients with prediabetes and T2DM with good glycemic control were randomly assigned either to receive 2 g/day carnosine or matching placebo. We evaluated endothelial dysfunction, arterial stiffness, lipid parameters, blood pressure, heart rate, hepatic and renal outcomes before and after the intervention. Carnosine supplementation had no effect on heart rate, peripheral and central blood pressure, endothelial function (logarithm of reactive hyperemia (LnRHI)), arterial stiffness (carotid femoral pulse wave velocity (CF PWV)), lipid parameters, liver fibroscan indicators, liver transient elastography, liver function tests, and renal outcomes compared to placebo. In conclusion, carnosine supplementation did not improve cardiovascular and cardiometabolic risk factors in adults with prediabetes and T2DM with good glycemic control. Therefore, it is improbable that carnosine supplementation would be a viable approach to mitigating the ASCVD risk in these populations. The trial was registered at clinicaltrials.gov (NCT02917928).
Poultry meat is a highly esteemed product among consumers. However, the emphasis on increasing body weight has led to a rise in the proportion of rapidly shrinking fibers, adversely affecting the quality and shelf life of poultry meat. With a growing awareness of dietetics among consumers, there is an increasing challenge to produce chicken meat that is not only free of antibiotics but also beneficial for dietary and health reasons. Biogenic amines (BA) can serve as indicators of meat freshness and quality. While they play vital roles in the body, excessive consumption of BA can have toxic and carcinogenic effects. The objective of this study was to examine the impact of supplementing feed with garlic extract and β-alanine (β-Ala) on the formation of BA and amino acid (AA) levels in the breast and leg muscles of chickens stored under aerobic chilling conditions. The muscles were obtained from chickens fed with garlic extract and β-Ala in quantities of 0.5% and 2% for each additive, as well as 0.5% and 2% of their combination. Analyses were conducted on d 1, 3, 5, 7, and 10 of storage. β-Ala supplementation increased the proportion of this AA in breast (P < 0.01) and leg muscles (P < 0.01), along with a rise in the proportion of non-essential AA (NEAA; sum of aspartic, aspartic acid, glutamic, glutamic acid, serine, β-Ala, and proline) (P < 0.01). The levels of BA changed during storage in breast and leg muscles (P < 0.001). The applied diet significantly influenced the formation of putrescine (P = 0.030), phenylethylamine (P = 0.003), agmatine (P = 0.025), and total BA (P < 0.001) in breast muscles. On the 10 d of storage, the breast muscles exhibited the lowest BA index (BAI) in the group, with a diet supplemented with 0.5% garlic extract and 0.5% β-Ala (P < 0.05). The leg muscles showed a similar BA trend as the breast muscles. These supplements may be utilized in production to augment the protein content of chicken muscles and potentially decrease the BAI index during meat storage.
Background: Muscle wasting is a serious complication in heart failure patients, and oxidative stress is involved in the pathogenesis of muscle wasting. Oxidative stress leads to the formation of toxic lipid peroxidation products, such as 4-hydroxy-2-nonenal (HNE) and acrolein, which causemuscle wasting. In tissues, these toxic aldehydes are metabolically removed by enzymes such asaldo keto reductases and endogenous nucleophiles, such as glutathione and carnosine. Whether these metabolic pathways could be affected in skeletal muscle during heart failure has never been studied.
Methods: Male wild-type C57BL/6J mice were subjected to a pressure overload model of hypertrophy by transaortic constriction (TAC) surgery, and echocardiography was performed after 14 weeks. Different skeletal muscle beds were weighed and analyzed for atrophic and inflammatory markers, Atrogin1 and TRIM63, TNF-α and IL-6, respectively, by RT‒PCR. Levels of acrolein and HNE-protein adducts, aldehyde-removing enzymes, aldose reductase (AKR1B1) and aldehyde dehydrogenase 2 (ALDH2) were measured by Western blotting, and histidyl dipeptides and histidyl dipeptide aldehyde conjugates were analyzed by LC/MS-MS in the gastrocnemius and soleus muscles of sham- and TAC-operated mice. Furthermore, histidyl dipeptide synthesizing enzyme carnosine synthase (CARNS) and amino acid transporters (PEPT2 and TAUT)wasmeasured in the gastrocnemius muscles of the sham and TAC-operated mice.
Results: TAC-induced heart failure decreases body weight and gastrocnemius and soleus muscle weights. The expression of the atrophic and inflammatory markers Atrogin1 and TNF-α, respectively, wasincreased (~1.5-2-fold), and the formation of HNE and acrolein-protein adducts was increased in the gastrocnemius muscle of TAC-operated mice. The expression of AKR1B1 remained unchanged, whereas ALDH2 was decreased, in the gastrocnemius muscle of TAC mice. Similarly, in the atrophic gastrocnemius muscle, levels of total histidyl dipeptides (carnosine and anserine) and, in particular,carnosine were decreased. Depletion of histidyl dipeptides diminished the aldehyde removal capacity of the atrophic gastrocnemius muscle. Furthermore, the expression of CARNS and TAUT wasdecreased in the atrophic gastrocnemius muscle.
Conclusions: Collectively, these results show that metabolic pathways involved in the removal of lipid peroxidation products and synthesis of histidyl dipeptides are diminished in atrophic skeletal muscle during heart failure, which could contribute to muscle atrophy.
Rathor, Richa, Sukanya Srivastava, and Geetha Suryakumar. A comparative biochemical study between L-carnosine and β-alanine in amelioration of hypobaric hypoxia-induced skeletal muscle protein loss. High Alt Med Biol 00:000-000, 2023. Background: Carnosine (CAR; β-alanyl-L-histidine), a biologically active dipeptide is known for its unique pH-buffering capacity, metal chelating activity, and antioxidant and antiglycation property. β-Alanine (ALA) is a nonessential amino acid and used to enhance performance and cognitive functions. Hypobaric hypoxia (HH)-induced muscle protein loss is regulated by multifaceted signaling pathways. The present study investigated the beneficial effects of CAR and ALA against HH-associated muscle loss. Methodology: Simulated HH exposure was performed in an animal decompression chamber. Gastric oral administration of CAR (50 mg·kg-1) and ALA (450 mg·kg-1) were given daily for 3 days and at the end of the treatment, hindlimb skeletal muscle tissue was excised for western blot and biochemical assays. Results: Cosupplementation of CAR and ALA alone was able to ameliorate the hypoxia-induced inflammation, oxidative stress (FOXO), ER stress (GRP-78), and atrophic signaling (MuRF-1) in the skeletal muscles. Creatinine phospho kinase activity and apoptosis were also decreased in CAR- and ALA-supplemented rats. However, CAR showed enhanced protection in HH-induced muscle loss as CAR supplementation was able to enhance protein concentration, body weight, and decreased the protein oxidation and ALA administration was not able to restore the same. Conclusions: Hence, the present comprehensive study supports the fact that CAR (50 mg·kg-1) is more beneficial as compared with ALA (450 mg·kg-1) in ameliorating the hypoxia-induced skeletal muscle loss.
Increasing evidence and our preliminary work have revealed the significant role of ferroptosis in acute kidney injury (AKI) induced by ischemia/reperfusion (IR). Carnosine (Car), a dipeptide consisting of β-alanine and L-histidine, has been shown to ameliorate HG-induced tubular epithelial cells inflammation. Whether Car exerts protective effects on AKI, and its molecular mechanism have not been clarified. Our in vivo and in vitro IR-AKI mouse models demonstrated that Car alleviates kidney injury, inflammation and ferroptosis. In hypoxia/reoxygenation (HR) induced human renal tubular epithelial cells (HK2), Car treatment reduced lipid peroxidation and iron accumulation, suppressed oxidative stress, and inhibited ferroptosis. Through cellular thermal shift assay (CETSA) and molecular docking, we identified GPX4 as a potential target that binds with Car. Further study showed that overexpressed GPX4 had a comparable protective effect on HK2 cells under HR conditions, similar to Car. Additionally, our findings demonstrated that Car exhibited similar anti-ferroptosis effects in both folic acid (FA)-induced AKI mouse models and Erastin induced HK2 cells. In conclusion, our results highlight that Car alleviate renal IR injury by inhibiting GPX4-mediated ferroptosis. Car shows promise as a potential therapeutic drug for IR-AKI and other diseases associated with ferroptosis.
Reactive oxygen species (ROS) are produced during oxidative metabolism in aerobic organisms. Under normal conditions, ROS production and elimination are in a relatively balanced state. However, under internal or external environmental stress, such as high glucose levels or UV radiation, ROS production can increase significantly, leading to oxidative stress. Excess ROS production not only damages biomolecules but is also closely associated with the pathogenesis of many diseases, such as skin photoaging, diabetes, and cancer. Antioxidant peptides (AOPs) are naturally occurring or artificially designed peptides that can reduce the levels of ROS and other pro-oxidants, thus showing great potential in the treatment of oxidative stress-related diseases. In this review, we discussed ROS production and its role in inducing oxidative stress-related diseases in humans. Additionally, we discussed the sources, mechanism of action, and evaluation methods of AOPs and provided directions for future studies on AOPs.
Carnosinase (i.e., CN1; E.C. 3.4.13.20) is an enzyme found in the sera of higher primates. CN1 preferentially catalyzes the hydrolysis of natural, orally adsorbed histidine dipeptides like carnosine (i.e., β-alanyl-L-histidine). This is the reason why carnosine has a limited use as a human food supplement or pharmacological agent, despite the promising results obtained in experiments on animal models of human diseases. Herein, an assay is reported for the measurement of serum CN1 activity. The method is intended for the screening of CN1 inhibitors able to enhance carnosine bioavailability in humans. The method was developed to monitor serum hydrolytic activity via the quantitation of one of the products of carnosine hydrolysis (i.e., histidine). Separation was achieved without using organic solvents by means of ion chromatography (IC), whereas detection was provided by UV spectroscopy. The assay herein reported is a green and cost-effective alternative to a recently published method based on hydrophilic interaction liquid chromatography (HILIC) and mass spectrometry (MS). The results show that such a method produces reliable measurements of serum hydrolytic activity and can be used for the screening of CN1 inhibitors.
Using nutritional interventions to cure and manage psychiatric disorders is a promising tool. In this regard, accumulating documents support strong relationships between the diet and brain health throughout the lifespan. Evidence from animal and human studies demonstrated that β-alanine (Beta-alanine; BA), a natural amino acid, provides several benefits in fight against cognitive decline promoting mental health. This review summarizes and reports state-of-the-art evidence on how BA affects cognitive health and argues existence of potential unrevealed biochemical mechanisms and signaling cascades. There is a growing body of evidence showing that BA supplement has a significant role in mental health mediating increase of the cell carnosine and brain-derived neurotrophic factor (BDNF) content. BDNF is one of the most studied neurotrophins in the mammalian brain, which activates several downstream functional cascades via the tropomyosin-related kinase receptor type B (TrkB). Activation of TrkB induces diverse processes, such as programmed cell death and neuronal viability, dendritic branching growth, dendritic spine formation and stabilization, synaptic development, cognitive-related processes, and synaptic plasticity. Carnosine exerts its main effect via its antioxidant properties. This critical antioxidant also scavenges hypochlorous acid (HOCl), another toxic species produced in mammalian cells. Carnosine regulates transcription of hundreds of genes related to antioxidant mechanisms by increasing expression of the nuclear erythroid 2-related factor 2 (Nrf2) and translocating Nrf2 to the nucleus. Another major protective effect of carnosine on the central nervous system (CNS) is related to its anti-glycating, anti-aggregate activities, anti-inflammatory, metal ion chelator activity, and regulation of pro-inflammatory cytokine secretion. These effects could be associated with the carnosine ability to form complexes with metal ions, particularly with zinc (Zn2+). Thus, it seems that BA via BDNF and carnosine mechanisms may improve brain health and cognitive function over the entire human lifespan.
SLC16A13, which encodes the monocarboxylate transporter 13 (MCT13), is a susceptibility gene for type 2 diabetes and is expressed in the liver and duodenum. Some peptidase-resistant oligopeptides are absorbed in the gastrointestinal tract and affect glycemic control in the body. Their efficient absorption is mediated by oligopeptide transporter(s) at the apical and basolateral membranes of the intestinal epithelia; however, the molecules responsible for basolateral oligopeptide transport have not been identified. In this study, we examined whether MCT13 functions as a novel basolateral oligopeptide transporter. We evaluated the uptake of oligopeptides and peptidomimetics in MCT13-transfected cells. The uptake of cephradine, a probe for peptide transport system(s), significantly increased in MCT13-transfected cells, and this increase was sensitive to membrane potential. The cellular accumulation of bioactive peptides, such as anserine and carnosine, was decreased by MCT13, indicating MCT13-mediated efflux transport activity. In polarized Caco-2 cells, MCT13 was localized at the basolateral membrane. MCT13 induction enhanced cephradine transport in an apical-to-basal direction across Caco-2 cells. These results indicate that MCT13 functions as a novel efflux transporter of oligopeptides and peptidomimetics, driven by electrochemical gradients across the plasma membrane, and it may be involved in the transport of these compounds across the intestinal epithelia.
L-Carnosine has various physiological functions and is widely used in cosmetics, medicine, food additives, and other fields. However, the yield of L-Carnosine obtained by biological methods is far from the level of industrial production. Herein, a cell factory for efficient synthesis of L-Carnosine was constructed based on transporter engineering and protein engineering. Firstly, a dipeptidase (SmpepD) was screened from Serratia marcescens through genome mining to construct a cell factory for synthesizing L-Carnosine. Subsequently, through rationally designed SmPepD, a double mutant T168S/G148D increased the L-Carnosine yield by 41.6% was obtained. Then, yeaS, a gene encoding the exporter of L-histidine, was deleted to further increase the production of L-Carnosine. Finally, L-Carnosine was produced by one-pot biotransformation in a 5 L bioreactor under optimized conditions with a yield of 133.2 mM. This study represented the highest yield of L-Carnosine synthesized in microorganisms and provided a biosynthetic pathway for the industrial production of L-Carnosine.
Purpose:
Exercise-induced hemolysis, which is caused by metabolic and/or mechanical stress during exercise, is considered a potential factor for upregulating hepcidin. Intramuscular carnosine has multiple effects including antioxidant activity. Therefore, this study aimed to determine whether long-term carnosine/anserine supplementation modulates exercise-induced hemolysis and subsequent hepcidin elevation.
Methods:
Seventeen healthy male participants were allocated to two different groups: participants consuming 1,500 mg/day of carnosine/anserine supplements (n = 9, C+A group) and participants consuming placebo powder supplements (n = 8, PLA group). The participants consumed carnosine/anserine or placebo supplements daily for 30.7 ± 0.4 days. They performed an 80-running session at 70% VO2peak pre-and post-supplementation. Iron regulation and inflammation in response to exercise were evaluated.
Results:
Serum iron concentrations significantly increased after exercise (p < 0.01) and serum haptoglobin concentrations decreased after exercise in both groups (p < 0.01). No significant differences in these variables were observed between pre-and post-supplementation. Serum hepcidin concentration significantly increased 180 min after exercise in both groups (p < 0.01). The integrated area under the curve of hepcidin significantly decreased after supplementation (p = 0.011) but did not vary between the C+A and PLA groups.
Conclusion:
Long-term carnosine/anserine supplementation does not affect iron metabolism after a single endurance exercise session.
Depression, anxiety, cognitive impairment, and pain are the most common mental symptoms exhibited in a wide range of diseases. Recent progress in neuroscience has led to better understanding of those dreadful symptoms; currently, state-of-the-art brain research attempts to untangle this complex phenomenon through preclinical, clinical, and computational approaches. This E-Book complies the most recent studies published in the Special Issue “Crosstalk between Depression, Anxiety, Dementia, and Chronic Pain: Comorbidity in Behavioral Neurology and Neuropsychiatry 2.0”, discussing the most recent cutting-edge research and its integrative potential of interdisciplinary arena for new study design and methodology in behavioral neurology and neuropsychiatry.
High growth rates and body weight are important traits of young dairy goats that can shorten generation intervals, improve animal performance, and increase economic benefits. In the present study, ninety-nine, 6-month-old, female goats were fed with the same diet and kept under the same management condition. The ten goats with highest average daily gain (ADG, HADG, 135.27 ± 4.59 g/d) and ten goats with lowest ADG (LADG, 87.74 ± 3.13 g/d) were selected to identify the key serum metabolites associated with ADG, and to investigate the relationships of serum metabolome profiles with digestive tract microbiota. The results showed that a total of 125 serum metabolites were significantly different between HADG and LADG. Of these, 43 serum metabolites were significantly higher levels in HADG, including D-ornithine, l-glutamine, L-histidine, carnosine, LysoPC (16:1(9Z)/0:0), DCTP and hydroxylysine, while, 82 serum metabolites were significantly higher levels in LADG, including P-salicylic acid and deoxycholic acid 3-glucuronide. Pathway analysis indicated that these different metabolites were mainly involved in amino acid and lipid metabolism. Furthermore, Spearman's rank correlation analysis revealed that these differential serum metabolites were correlated with ADG and ADG-related bacteria. Notably, serum hydroxylysine and L-histidine could be used as biomarkers for distinguishing HADG and LADG goats, with an accuracy of >92.0%. SIGNIFICANCE: Our study confirms that individual microbiota and metabolic differences contribute to the variations of growth rate in young goats. Some serum metabolites may be useful in improving the growth performance of young goats, which provides directions for developing further nutritional regulation in the goat industry to achieve healthy feeding and efficiency enhancement.
This work reveals how two natural multi-target compounds (Carnosine and Homocarnosine) can prevent the oligomerization of beta-amyloid peptides (A[Formula: see text]. Properly combining molecular dynamics, docking and electronic structure calculations it was possible to investigate how Carnosine/Homocarnosine strongly interact with the amino acids of the A[Formula: see text](1-42) peptide responsible for the complexation with metallic ions (metallic hypothesis). This discovery may prevent the formation of harmful protein deposits, thereby preventing the progression of, for example, Alzheimer’s disease (AD). These important results suggest that Carnosine/Homocarnosine can interact with, at least, two of the amino acids responsible for the complexation of the A[Formula: see text](1-42) peptide with the metallic ion copper(II). These findings open a new perspective on the inhibitory potential of these molecules in the treatment of AD and other neurodegenerative diseases.
Calcium signalling underlies much of physiology. Almost all the Ca2+ in the cytoplasm is bound to buffers, with typically only about 1% being freely ionized at resting levels in most cells. Physiological Ca2+ buffers include small molecules and proteins, and experimentally, Ca2+ indicators will also buffer calcium. The chemistry of interactions between Ca2+ and buffers determines the extent and speed of Ca2+ binding. The physiological effects of Ca2+ buffers are determined by the kinetics with which they bind Ca2+ and their mobility within the cell. The degree of buffering depends on factors such as the affinity for Ca2+, the Ca2+ concentration, and whether Ca2+ ions bind cooperatively. Buffering affects both the amplitude and time course of cytoplasmic Ca2+ signals as well as changes of Ca2+ concentration in organelles. It can also facilitate Ca2+ diffusion inside the cell. Ca2+ buffering affects synaptic transmission, muscle contraction, Ca2+ transport across epithelia, and the killing of bacteria. Saturation of buffers leads to synaptic facilitation, tetanic contraction in skeletal muscle, and may play a role in inotropy in the heart. This review focuses on the link between buffer chemistry and function and how Ca2+ buffering affects normal physiology and the consequences of changes in disease. As well as summarizing what is known, we point out the many areas where further work is required.
The microbiomes of cesarean-born infants differ from vaginally delivered infants and are associated with increased disease risks. Vaginal microbiota transfer (VMT) to newborns may reverse C-section-related microbiome disturbances. Here, we evaluated the effect of VMT by exposing newborns to maternal vaginal fluids and assessing neurodevelopment, as well as the fecal microbiota and metabolome. Sixty-eight cesarean-delivered infants were randomly assigned a VMT or saline gauze intervention immediately after delivery in a triple-blind manner (ChiCTR2000031326). Adverse events were not significantly different between the two groups. Infant neurodevelopment, as measured by the Ages and Stages Questionnaire (ASQ-3) score at 6 months, was significantly higher with VMT than saline. VMT significantly accelerated gut microbiota maturation and regulated levels of certain fecal metabolites and metabolic functions, including carbohydrate, energy, and amino acid metabolisms, within 42 days after birth. Overall, VMT is likely safe and may partially normalize neurodevelopment and the fecal microbiome in cesarean-delivered infants.
Here we report the cloning and functional characterization of a rat novel peptide/histidine transporter (PHT1), which was expressed in the brain and the retina. The cDNA encodes the predicted protein of 572 amino acid residues with 12 putative membrane-spanning domains. The amino acid sequence has moderate homology with a nonspecific peptide transporter found in the plant. When expressed in Xenopus laevis oocytes, PHT1 cRNA induced high affinity proton-dependent histidine transport activity. This transport process was inhibited by dipeptides and tripeptides but not by free amino acids such as glutamate, glycine, leucine, methionine, and aspartate. Dipeptide carnosine transport activity was also confirmed by direct uptake measurement. By in situ hybridization analysis, PHT1 mRNA was widely distributed throughout whole brain. Especially, intense hybridization signals were found in the hippocampus, choroid plexus, cerebellum, and pontine nucleus. Signals were located in both the neuronal and small nonneuronal cells in these areas. PHT1 protein could contribute to uptake of oligopeptides, which function as neuromodulators, and clearance of degraded neuropeptides and be a new member in the growing superfamily of proton-coupled peptide and nitrate transporters, although its structure, localization, and pharmacological characteristics are unique among these members.
Muscle carnosine synthesis is limited by the availability of β-alanine. Thirteen male subjects were supplemented with β-alanine
(CarnoSyn™) for 4 wks, 8 of these for 10 wks. A biopsy of the vastus lateralis was obtained from 6 of the 8 at 0, 4 and 10 wks. Subjects undertook a cycle capacity test to determine total work done (TWD)
at 110% (CCT110%) of their maximum power (Wmax). Twelve matched subjects received a placebo. Eleven of these completed the CCT110% at 0 and 4 wks, and 8, 10 wks. Muscle biopsies were obtained from 5 of the 8 and one additional subject. Muscle carnosine
was significantly increased by +58.8% and +80.1% after 4 and 10 wks β-alanine supplementation. Carnosine, initially 1.71 times
higher in type IIa fibres, increased equally in both type I and IIa fibres. No increase was seen in control subjects. Taurine
was unchanged by 10 wks of supplementation. 4 wks β-alanine supplementation resulted in a significant increase in TWD (+13.0%);
with a further +3.2% increase at 10 wks. TWD was unchanged at 4 and 10 wks in the control subjects. The increase in TWD with
supplementation followed the increase in muscle carnosine.
It has been suggested that histidine-containing dipeptide carnosine ( -alanyl-L-histidine), which is believed to act as a cytosolic buffering agent, is present predominantly in skeletal muscle. The purpose of this study was to investigate the effects of sprint training (30-s maximal cycle ergometer sprinting) on muscle carnosine concentration. Six untrained males trained 2 days per week for 8 weeks on an electronic-braked cycle ergometer. Muscle biopsy samples were taken from the vastus lateralis before and two days after the last training session and were analyzed for carnosine concentration by the use of an amino acid autoanalyzer. The carnosine concentration was signifi cantly increased after sprint training ( P concentration was signifi cantly increased after sprint training ( P concentration was signifi cantly increased after sprint training ( < 0.05). The mean power P < 0.05). The mean power P during 30-s maximal cycle ergometer sprinting was signifi cantly increased following training. When dividing the 30-s sprinting into 6 phases (0-5, 6-10, 11-15, 16-20, 21-25, 26-30 s), the magnitude of increase in mean power was signifi cantly larger for the last 2 phases than the fi rst phase ( P fi rst phase ( P fi rst phase ( < 0.05). These results suggest that the increases in skeletal muscle carnosine P < 0.05). These results suggest that the increases in skeletal muscle carnosine P concentration following sprint training may be associated with the increase in sustainability of high power during 30-s maximal cycle ergometer sprinting.
Significance
The concentration of Ca ²⁺ ions is kept low in cells by specialized ion-pumping proteins at the membrane. We show that in cardiac cells, cytoplasm also has an intrinsic ability to pump Ca ²⁺ . Histidyl dipeptides and ATP are diffusible cytoplasmic buffer molecules. By exchanging Ca ²⁺ for H ⁺ , they act like local “pumps,” producing uphill Ca ²⁺ movement within cytoplasm in response to H ⁺ ion gradients. Intracellular H ⁺ ions are generated locally by metabolism and competitively inhibit many Ca ²⁺ -activated biochemical processes. Recruiting Ca ²⁺ to acidic zones facilitates these processes. Cytoplasmic histidyl dipeptides and ATP thus act like a biological pump without a membrane.
Anserine (beta-alanyl-N(Pi)-methyl-L-histidine), a naturally occurring derivative of carnosine (beta-alanyl-L-histidine), is an abundant constituent of skeletal muscles and brain of many vertebrates. Although it has long been proposed to serve as a proton buffer, radicals scavenger and transglycating agent, its physiological function remains obscure. The formation of anserine is catalyzed by carnosine N-methyltransferase which exhibits unknown molecular identity. In the present investigation, we have purified carnosine N-methyltransferase from chicken pectoral muscle about 640-fold until three major polypeptides of about 23, 26 and 37 kDa coeluting with the enzyme were identified in the preparation. Mass spectrometry analysis of these polypeptides resulted in an identification of histamine N-methyltransferase-like (HNMT-like) protein as the only meaningful candidate. Analysis of GenBank database records indicated that the hnmt-like gene might be a paralogue of histamine N-methyltransferase gene, while comparison of their protein sequences suggested that HNMT-like protein might have acquired a new activity. Chicken HNMT-like protein was expressed in COS-7 cells, purified to homogeneity, and shown to catalyze the formation of anserine as confirmed by both chromatographic and mass spectrometry analysis. Both specificity and kinetic studies carried out on the native and recombinant enzyme were in agreement with published data. Particularly, several compounds structurally related to carnosine, including histamine and L-histidine, were tested as potential substrates for the enzyme, and carnosine was the only methyl group acceptor. The identification of the gene encoding carnosine N-methyltransferase might be beneficial for estimation of the biological functions of anserine.
About 25% of 1990-1991 Persian Gulf War veterans experience disabling fatigue, widespread pain, and cognitive dysfunction termed Gulf War illness (GWI) or Chronic Multisymptom Illness (CMI). A leading theory proposes that wartime exposures initiated prolonged production of reactive oxygen species (ROS) and central nervous system injury. The endogenous antioxidant L-carnosine (B-alanyl-L-histidine) is a potential treatment since it is a free radical scavenger in nervous tissue. To determine if nutritional supplementation with L-carnosine would significantly improve pain, cognition and fatigue in GWI, a randomized double blind placebo controlled 12 week dose escalation study involving 25 GWI subjects was employed. L-carnosine was given as 500, 1000, and 1500 mg increasing at 4 week intervals. Outcomes included subjective fatigue, pain and psychosocial questionnaires, and instantaneous fatigue and activity levels recorded by ActiWatch Score devices. Cognitive function was evaluated by WAIS-R digit symbol substitution test. Carnosine had 2 potentially beneficial effects: WAIS-R scores increased significantly, and there was a decrease in diarrhea associated with irritable bowel syndrome. No other significant incremental changes were found. Therefore, 12 weeks of carnosine (1500 mg) may have beneficial cognitive effects in GWI. Fatigue, pain, hyperalgesia, activity and other outcomes were resistant to treatment.
Several linkage analyses have mapped a susceptibility locus for diabetic nephropathy to chromosome 18q22-23, and polymorphisms within the carnosine dipeptidase 1 gene (CNDP1), located on 18q22.3, have been shown to be associated with diabetic nephropathy in European subjects with type 2 diabetes. However, the association of this locus with diabetic nephropathy has not been evaluated in the Japanese population. In this study, we examined the association of polymorphisms within the CNDP1/CNDP 2 locus with diabetic nephropathy in Japanese subjects with type 2 diabetes.
We genotyped a leucine repeat polymorphism (D18S880) that is within CNDP1 along with 29 single nucleotide polymorphisms (SNPs) in the CNDP1/CNDP2 locus for 2,740 Japanese subjects with type 2 diabetes (1,205 nephropathy cases with overt nephropathy or with end-stage renal disease [ESRD], and 1,535 controls with normoalbuminuria). The association of each polymorphism with diabetic nephropathy was analysed by performing logistic regression analysis. We did not observe any association between D18S880 and diabetic nephropathy in Japanese subjects with type 2 diabetes. None of the 29 SNPs within the CNDP1/CNDP2 locus were associated with diabetic nephropathy, but a subsequent sex-stratified analysis revealed that 1 SNP in CNDP1 was nominally associated with diabetic nephropathy in women (rs12604675-A; p = 0.005, odds ratio [OR] = 1.76, 95% confidence interval [CI], 1.19-2.61). Rs12604675 was associated with overt proteinuria (p = 0.002, OR = 2.18, 95% CI, 1.32-3.60), but not with ESRD in Japanese women with type 2 diabetes.
Rs12604675-A in CNDP1 may confer susceptibility to overt proteinuria in Japanese women with type 2 diabetes.
The enzyme myeloperoxidase generates significant amounts of hypochlorous acid (HOCl) at sites of inflammation to inflict oxidative damage upon invading pathogens. However, excessive production of this potent oxidant is associated with numerous inflammatory diseases. Recent kinetic measurements suggest that the endogenous antioxidant carnosine is an effective HOCl scavenger. On the basis of computational modeling, we suggest a possible mechanism for this antioxidant activity. We find that a unique structural relationship between three adjacent functional groups (imidazole, carboxylic acid, and terminal amine) enables an intramolecular chlorine transfer to occur. In particular, two sequential proton shifts are coupled with a Cl(+) shift converting the kinetically favored product (chlorinated at the imidazole nitrogen) into the thermodynamically favored product (chlorinated at the terminal amine) effectively trapping the chlorine. We proceed to design systems that share similar structural features to those of carnosine but with even greater HOCl-scavenging capabilities.
Autism spectrum disorders (ASD) are a group of biological disorders with associated metabolic derangement. This study aimed to identify a pattern of metabolic perturbance in ASD using metabolomics in urinary specimens from 48 children with ASD and 53 age matched controls. Using a combination of liquid- and gas-chromatography-based mass spectrometry, we detected the levels of 82 metabolites (53 of which were increased) that were significantly altered between the ASD and the control groups using osmolality normalized data. Pattern analysis showed that the levels of several amino acids such as glycine, serine, threonine, alanine, histidine, glutamyl amino acids and the organic acid, taurine were significantly (p≤0.05) lower in ASD children. The levels of antioxidants such as carnosine were also reduced in ASD (p=0.054). Furthermore, several gut bacterial metabolites were significantly altered in ASD children who had gastrointestinal dysfunction. Overall, this study detected abnormal amino acid metabolism, increased oxidative stress, and altered gut microbiomes in ASD. The relationship of altered gut microbial co-metabolism and the disrupted metabolisms requires further investigation.
Cisplatin mediated nephrotoxicity is remarkably documented by reactive oxygen species. Carnosine is a naturally occurring dipeptide and has a scavenging property. The aim of present study was to assess the lipid peroxidation and antioxidant enzymes in association with oxidative stress in cisplatin -treated and 10 subsequent doses of carnosine-pretreated rats. 24 male Albino Wistar rats, were randomly divided into four groups (n=6). Group I remains untreated; Group II received Cisplatin (3 mg / kg) for 5 alternate days; Group III received Carnosine (10 mg / kg) for consecutive 10 days; Group IV received Carnosine (10 mg / kg) before administration of Cisplatin (3 mg / kg). The effects of carnosine on cisplatin-induced nephrotoxicity were evaluated by plasma creatinine, urea, malondialdehyde, nitrate; kidney tissue malondialdehyde, 4-HNE, superoxide dismutase and catalase activities. Cisplatin-induced oxidative stress was indicated by increased level of tissue MDA, 4-HNE and decreased level of tissue GSH, SOD and Catalase. Marked elevation of kidney weight and reduced body weight and pathological changes in kidney tissues were also observed in Cisplatin-treated rats. Carnosine reduced these pathological changes and counteracted the deleterious effects of cisplatin. The results divulge the beneficial effect of Carnosine pretreatment with cisplatin in experimental rat model.
Our goal in this study was to determine whether or not feeding young (4 months old) Alzheimer's disease model transgenic mice with a high fat diet (HFD), consisting of 32% fat, is capable of causing cognitive decline and whether treatment with β-alanyl-L-histidine (carnosine) is capable of reducing these effects. Carnosine is an endogenous antioxidant and antiglycating agent that is abundantly present in the brain and muscle tissues of vertebrates. After 8 weeks of feeding with HFD, we observed a significant decline in the contextual memory in transgenic mice fed with HFD as compared to transgenic mice fed with a normal diet as well as to normal diet-wild type mice. Treatment with carnosine at a dose of 5 mg/day for 6 weeks was effective in preventing cognitive decline, as the transgenic group fed with HFD and treated with carnosine displayed a level of cognition comparable to controls. No differences in senile plaque load were observed between all groups. However, we observed an increase in the expression of RAGE in blood vessels as well as increased microglial activation in the hippocampus of animals fed with HFD, effects that were reversed when treated with carnosine. Given these results, there is a possibility that inflammation and cerebrovascular abnormalities might be the cause of cognitive decline in this model.
β-alanine, a popular supplement for muscle building, induces itch and tingling after consumption, but the underlying molecular and neural mechanisms are obscure. Here we show that, in mice, β-alanine elicited itch-associated behavior that requires MrgprD, a G-protein-coupled receptor expressed by a subpopulation of primary sensory neurons. These neurons exclusively innervate the skin, respond to β-alanine, heat, and mechanical noxious stimuli but do not respond to histamine. In humans, intradermally injected β-alanine induced itch but neither wheal nor flare, suggesting that the itch was not mediated by histamine. Thus, the primary sensory neurons responsive to β-alanine are likely part of a histamine-independent itch neural circuit and a target for treating clinical itch that is unrelieved by anti-histamines.
This manuscript concerns the tissue specific transcription of mouse and cattle glutamate decarboxylase-like 1 (GADL1) and the biochemical activities of human GADL1 recombinant protein. Bioinformatic analysis suggested that GADL1 appears late in evolution, only being found in reptiles, birds, and mammals. RT-PCR determined that GADL1 mRNA is transcribed at high levels in mouse and cattle skeletal muscles and also in mouse kidneys. Substrate screening determined that GADL1, unlike its name implies, has no detectable GAD activity, but it is able to efficiently catalyze decarboxylation of aspartate, cysteine sulfinic acid, and cysteic acid to β-alanine, hypotaurine, and taurine, respectively. Western blot analysis verified the presence of GADL1 in mouse muscles, kidneys, C2C12 myoblasts, and C2C12 myotubes. Incubation of the supernatant of fresh muscle or kidney extracts with cysteine sulfinic acid resulted in the detection of hypotaurine or taurine in the reaction mixtures, suggesting the possible involvement of GADL1 in taurine biosynthesis. However, when the tissue samples were incubated with aspartate, no β-alanine production was observed. We proposed several possibilities that might explain the inactivation of ADC activity of GADL1 in tissue protein extracts. Although β-alanine-producing activity was not detected in the supernatant of tissue protein extracts, its potential role in β-alanine synthesis cannot be excluded. There are several inhibitors of the ADC activity of GADL1 identified. The discovery of GADL1 biochemical activities, in conjunction with its expression and activities in muscles and kidneys, provide some tangible insight towards establishing its physiological function(s).
Spektrophotometrische, pH-metri - sche und teilweise 13C-NMR-spektroskopische Untersuchungen der Komplexe von Co(II), Ni(Il) und Zn(II) mit Gly-L-His, L-His-Gly und L-Camosin zeigen die unterschiedliche Art der Koordination und die dadurch bedingte Bildung verschiedener Gemischt-ligand-Komplexe mit Gly, Gly-Gly, His und 2,2′-Bipyridyl als zweitem Liganden.
Carnosine (β-alanyl-L-histidine) exhibits anti-oxidant and anti-glycation properties, which are attributed to carnosine's ability to scavenge radicals and sugar aldehydes. Carnosine protects against glycation-induced loss of enzyme activity and prevents glycation-induced changes in protein structure. Carnosine's anti-glycation properties coincide with adduct formation between carnosine and sugar aldehydes. This study examined the glycation product formed during incubation of carnosine with glyceraldehyde 3-phosphate (Glyc3P) using mixtures containing unreactive reactants. The initially clear solution became bright yellow upon incubation. The fluorescence and absorbance properties were studied. The increase in fluorescence (365 nm ex; 460 nm em) was time-, concentration- and temperature-dependent. The absorbance spectra exhibited a 288 nm peak. The carnosine-Glyc3P adduct had a decreased amino group content suggesting a role for the β-alanyl's amino group in the formation of a Maillard reaction product (The Maillard Reaction, R. Ikan, ed., John Wiley & Sons, 1996). Aspartate aminotransferase activity, which was used as a measure of glycation-induced inactivation, was only moderated affected by the carnosine-Glyc3P glycation product in comparison to Glyc3P, supporting carnosine's role as a protective agent.
Background: Substantial differences exist between traditionally cooked and chemically designed ready-to-serve products and raise questions about the general principles and requirements of current food law. Methods: Differences in amino acid patterns were analyzed in four examples of chicken preparations (boiled chicken meat, traditionally prepared broth from whole chicken, and two commercial chicken broths), and four examples of vegetable broth (traditionally prepared, two commercial products one of which was claimed a BIO-product, and the classic German bouillon cube). Results: Chicken meat contained 284 mg of free amino acids in 100 ml of the boiled meat homogenate, with physiological peaks of glutamate (14.5 mg/100 ml), glutamine (8.5 mg/100 ml), anserine (88 mg/100 ml) and carnosine (55 mg/100 ml). The patterns significantly differ in industrially designed chicken soups with elevated peaks of glutamate, and missing anserine or carnosine. Similar results were obtained in vegetable broths. In the classic German bouillon cube, glutamate accounts for 96% of all free amino acids. Conclusions: The amino acid composition of modern ready-to-serve chicken soups and vegetable broths are far from being similar to any natural composition. We need to question current legal definitions of food, and consider its impact on eating habits, appetite regulation and obesity.
The effect of carnosine on the life span and several brain biochemical characteristics in senescence-accelerated mice-prone 1 (SAMP1) was investigated. A 50% survival rate of animals treated with carnosine increased by 20% as compared to controls. Moreover, the number of animals that lived to an old age significantly increased. The effect of carnosine on life span was accompanied by a decrease in the level of 2'-tiobarbituric acid reactive substances (TBARS), monoamine oxidase b (MAO b), and Na/K-ATPase activity. There was also an increase in glutamate binding to N-methyl-D-aspartate receptors. These observations are consistent with the conclusion that carnosine increases life span and quality of life by diminishing production of lipid peroxides and reducing the influence of reactive oxygen species (ROS) on membrane proteins.
Objective dietary intake markers for meat would be useful to assess meat intake in observational studies and as compliance markers in dietary intervention studies. A number of compounds are specific to meat compared with most other dietary items but there is some overlap between protein rich foods. A number of single compounds have been analysed in urine, plasma, serum or hair samples in studies of their relationship to meat or total protein intake. Among potential markers of dietary meat intake are urea, creatine, creatinine, carnitine, carnosine, anserine, ophidine, 1- and 3-methylhistidine, and sulphate or sulphite. Anserine and 1-methylhistidine come close to being meat-specific markers but true quantitative biomarker may not exist. Modern profiling techniques are increasingly used to look for useful biomarkers or for constructing them from latent information in complex profiles. Metabolomics by NMR spectroscopy of urine has also been applied to search for meat intake markers. Studies on single com
Objective dietary intake markers for meat would be useful to assess meat intake in observational studies and as compliance markers in dietary intervention studies. A number of compounds are specific to meat compared with most other dietary items but there is some overlap between protein rich foods. A number of single compounds have been analysed in urine, plasma, serum or hair samples in studies of their relationship to meat or total protein intake. Among potential markers of dietary meat intake are urea, creatine, creatinine, carnitine, carnosine, anserine, ophidine, 1- and 3-methylhistidine, and sulphate or sulphite. Anserine and 1-methylhistidine come close to being meat-specific markers but true quantitative biomarker may not exist. Modern profiling techniques are increasingly used to look for useful biomarkers or for constructing them from latent information in complex profiles. Metabolomics by NMR spectroscopy of urine has also been applied to search for meat intake markers. Studies on single compounds or metabolomics markers are shortly reviewed here
Carnosine in the chemoreceptor neurons of the olfactory epithelium can be labeled in vivo by intranasal irrigation with either(14)C-β-alanine or(14)C-L-histidine. This newly synthesized carnosine (but not the precursor amino acids) is translocated to the olfactory bulb, where the olfactory chemoreceptor axons synapse with the dendrites of mitral cells and other second-order neurons. Labeled carnosine arrives in the bulb several hours after intranasal administration of precursor. Similar arrival time is seen for macromolecules after intranasal administration of [(3)H]L-fucose, [(14)C]L-proline, or [(14)C]L-histidine. Macromolecules labeled with [(3)H]uridine take much longer to reach the bulb. Carnosine is also labeled after [(3)H]uridine administration. No labeling of macromolecules is observed after administration of 1-[(14)C]-β-alanine. Oral administration of the same dose of [(14)C]-β-alanine gives almost no labeled carnosine in bulb or epithelium. This method has permitted us to estimate that the half-life of labeled carnosine in both the bulb and epithelium is about 20 h. This method provides a means of selectively prelabeling the olfactory chemoreceptor neurons in the olfactory epithelium and their synapses in the olfactory bulb prior to cellular and subcellular separation procedures, and may also enable us to monitor the influences of olfactory stimulation on synthesis and transport of carnosine.
The aim of this work was to test the hypothesis that in vivo carnosine biosynthesis is dependent upon endogenous ß-alanine availability, by studying the effect of sustained dietary ß-alanine supplementation in the horse on the carnosine concentration in types I, IIA and IIB skeletal muscle fibres. The diets of 6 Thoroughbred horses were supplemented 3 times/day with ß-alanine (100 mg/kg bwt) and L-histidine (12.5 mg/kg bwt) for a period of 30 days. Percutaneous biopsies of the m. gluteus medius from a depth of 6 cm were taken on the days immediately before and after the supplementation period. Heparinised blood samples were collected at hourly intervals on the first and last days of supplementation, and on every sixth day during the supplementation period, 2 h after each ration. Individual muscle fibres were dissected from freeze-dried biopsies, weighed and characterised histochemically. ß-alanine, histidine and carnosine concentrations were measured in plasma. The areas under the plasma concentration-time curves (AUC) for ß-alanine and histidine were calculated as indicators of the doses absorbed. Carnosine concentrations were measured in types I, IIA and IIB muscle fibres.
Carnosine (α-alanyl-l-histidine), a dipeptide, the exact functions of which are unknown, is found at millimolar concentrations in muscle cells. In skinned skeletal muscle fibers, carnosine released calcium from the sarcoplasmic reticulum and generated tension, and carnosine (ED50 = 6.6 mM) was less potent than caffeine (ED50 = 1.5 mM). The effect of carnosine on the ryanodine receptor calcium release channel (Ry1) was investigated in single Ryl molecules incorporated into an artificial lipid bilayer for recording channel activity. Carnosine (0.1-10 mM) increased open-state probability (Po) of Ry1 with a fourfold maximal increase occurring at 2.5 mM. Carnosine (5 mM) caused a twofold increase in the open-state dwell time. Carnosine also altered the Ry1 channel’s response to changes in calcium concentration, shifting the Po-versus-pCa relationship to the left. The presence of carnosine at a millimolar concentration in muscle cells and its effects on the major calcium release channel in skeletal muscle suggest an important function for this unique dipeptide in regulation of contractility. One possible function of carnosine is the sensitization of key proteins to activation and/or inactivation by Ca2+.Copyright © 1997 S. Karger AG, Basel
1.1. From the muscle of 20 species of fresh-water fishes, l-histidine, carnosine, anserine, and balenine were analysed by high-performance liquid chromatography.2.2. All cyprinoidei fishes contained significant amount of l-histidine and trace of dipeptides.3.3. High concentration of anserine was found in salmonoidei fishes, irrespective of salmonidae and osmeridae.4.4. Two species of anguilloidei contained large amount of carnosine, small of l-histidine, and determinable of anserine and balenine.5.5. Only trace amounts of these compounds were found in percoidei fishes.6.6. The levels of these compounds represented no large difference among species belonging to sub-order group as well as family.
The glycyl-L-histidine (GlyHis), L-histidylglycine (HisGly), and L-carnosine (ligands HA) parent complexes of cobalt(II), nickel(II), and zinc(II) were studied by pH-metry, spectrophotometry, and in part 13C n.m.r. spectroscopy. All three metal ions were found to promote deprotonation of the peptide amide group of GlyHis. HisGly co-ordinates ‘histidine-like’ to the metal ions, i.e. without deprotonation of the peptide amide group. With carnosine, only nickel(II) induces deprotonation of this group. Studies were also made of mixed-ligand systems involving Gly, GlyGly, His, and occasionally 2,2′-bipyridyl as second ligand B, including those containing copper(II). Gly and GlyGly do not hinder the co-ordination of GlyHis via three nitrogens, and mixed-ligand complexes are therefore not present in detectable concentration. With His as ligand B, although mixed-ligand complexes are formed at comparable GlyHis and His concentrations, in the presence of an excess of His the parent complex [M(HisO)2] predominates. A mixed-ligand complex is obtained in significant amount with 2,2′-bipyridyl as ligand B. Appreciable formation of mixed-ligand complexes also occurs in the nickel(II)–carnosine–ligand B systems. For cobalt(II), however, practically only the parent complexes of ligands B are formed. The cobalt(II) complexes of all three dipeptides examined are able to take up molecular oxygen reversibly, the oxygen being released partially or almost completely. For GlyHis it is highly likely that the active complex is [Co(AH–1)], while for HisGly and carnosine the presence of the bis complexes is presumed necessary for oxygen uptake.
The stability of the copper(II)–carnosine dimer in aqueous solutions at pH 7.2 has been investigated with Fourier transform–i.r. and e.s.r. spectroscopies. At subsaturated concentrations, the dimer dissociates into two identical monomers. However, the dimer does not dissociate in saturated solutions even at temperatures as high as 80 °C according to Fourier-transform i.r. spectra. Motional averaging of the dipolar coupling tensors occurs at temperatures at least as low as 15 °C. Thus at temperatures above the freezing point of the solvent the copper(II) dimer in saturated solution exhibits a spectrum with only four hyperfine lines. These are broader than the hyperfine lines of monomeric copper(II) complexes because of dipole–dipole interaction. This is the first spectroscopic confirmation to our knowledge that a copper(II) dimer need not dissociate in aqueous solution at temperatures above the freezing point of water.
A feeding experiment involving histidine supplementation to broiler feed resulted in increased concentration of the histidine containing dipeptides anserine and carnosine in broiler breast muscle. Supplementation with 1 g histidine per kg feed gave a 64% increase in carnosine, and about 10% increase in anserine in the muscle. The standard broiler feed concentrate now in use in Norway seems to contain less histidine than what may be needed for optimal synthesis of carnosine and anserine. These dipeptides have important roles as antioxidants, pH buffering agents and anti-glycation agents. They may have important roles in meat for increasing its stability, shelf life and antioxidant capacity, and it might be speculated that broiler meat rich in anserine and carnosine in the future will be considered a type of functional food, having possible health-beneficial effects. Histidine supplementation of standard Norwegian broiler feed concentrate should be considered.
— Singlet molecular oxygen was generated by illumination of phenosafranin in phosphate buffer at pH 7.5. Relative efficiencies of various imidazole compounds to form endoperoxides were assayed by following at 25°C the rate of light- and imidazole-dependent bleaching of N,N-dimethyl-4-nitrosoaniline. Of over 30 imidazole compounds tested, imidazole-4-acetic acid, a major catabolite of histamine in mammals, exhibited the highest activity. l-Carnosine (β-alanyl-l-histidine), a natural dipeptide prevalent in striated muscle of mammals, possessed several properties important for a physiologically significant scavenger of singlet oxygen. On a molar basis, this readily water-soluble C-terminal histidine dipeptide reacted with singlet oxygen two-to four-fold faster than free L-histidine and approximately two-fold faster than the N-terminal l-histidine dipeptides tested. Furthermore scavenging ability of L-carnosine did not appreciably increase or decrease with time of reaction, in contrast to behaviors exhibited by a number of other imidazole compounds that included some other C-terminal L-histidine dipeptides. The fungal metabolite, ergothioneine, blocked singlet oxygen generation by illuminated phenosafranin.