320 research outputs found
An update on carnosine and anserine research
No full textCarnosine belongs to a family of histidyl dipeptides, consisting of l-histidine and beta-alanine. It is more prevalent in the mammalian and human tissues, whereas its analogues such as anserine, which is methylated at the Nπ of imidazole, is present in birds and fish and balenine, methylated at the Nτ of histidine, is largely present in marine mammals and reptiles (Boldyrev et al. 2013). Despite their early discovery and their prominent concentrations in certain tissues, the exact role and potential of these dipeptides are still not fully understood. Carnosine is a multifunctional dipeptide. Based on its biochemical properties, it has been suggested to be involved in acid–base balance, antioxidant defense and scavenging of lipid peroxidation products. The latter functions of the dipeptide have generated various expectations as therapeutic interventions, e.g. for the pathologies associated with enhanced generation of lipid peroxidation products.
There is a growing interest from the broad scientific community to unravel the fundamental properties as well as the potential application spectrum of carnosine and related dipeptides. As to date (December 2018), over 3300 publications are found on Web of Science when searching for ‘carnosine’, and Fig. 1 displays the fundamental (panel A) and applied research areas (panel B) in which these papers are mostly situated. The majority of fundamental research is performed in the field of biochemistry/molecular biology, pharmacology and physiology (Fig. 1a). The major application fields are neurology, diabetes, cardiovascular disease and nutrition (Fig. 1b), although the interest and relevance are broad and extends all the way to agriculture, zoology, sports sciences, etc. The wide variety of disciplines of the manuscripts in this current Special Issue is a reflection hereof.No Full Tex
The influence of sex, age and heritability on human skeletal muscle carnosine content
No full textThe dipeptide carnosine is found in high concentrations in human skeletal muscle and shows large interindividual differences. Sex and age are determining factors, however, systematic studies investigating the sex effects on muscle carnosine content throughout the human lifespan are lacking. Despite the large inter-individual variation, the intra-individual variation is limited. The question may be asked whether the carnosine content is a muscle characteristic which may be largely genetically determined. A total of 263 healthy male and female subjects of 9–83 years were divided into five different age groups: prepubertal children (PC), adolescents (A), young adults (YA), middle adults (MA) and elderly (E). We included 25 monozygotic and 22 dizygotic twin pairs among the entire study population to study the heritability. The carnosine content was measured non-invasively in the gastrocnemius medialis and soleus by proton magnetic resonance spectroscopy (1H-MRS). In boys, carnosine content was significantly higher (gastrocnemius 22.9%; soleus 44.6%) in A compared to PC, while it did not differ in girls. A decrease
(*16%) was observed both in males and females from YA to MA. However, elderly did not have lower carnosine levels in comparison with MA. Higher correlations were found in monozygotic (r = 0.86) compared to dizygotic (r = 0.51) twins, in soleus muscle, but not in gastrocnemius. In conclusion, this study found an effect of puberty on muscle carnosine content in males, but not in females. Muscle carnosine decreased mainly during early adulthood and hardly from adulthood to elderly. High intra-twin correlations were observed, but muscle-dependent differences preclude clear conclusions toward heritability
Reduced muscle carnosine content in type 2, but not in type 1
No full textCarnosine is present in high concentrations in skeletal muscle where it contributes to acid buffering and functions also as a natural protector against oxidative and carbonyl stress. Animal studies have shown an anti-diabetic effect of carnosine supplementation. High carnosinase activity, the carnosine degrading enzyme in serum, is a risk factor for diabetic complications in humans. The aim of the present study was to compare the muscle carnosine concentration in diabetic subjects to the level in non-diabetics. Type 1 and 2 diabetic patients and matched healthy controls (total n = 58) were included in the study. Muscle carnosine content was evaluated by proton magnetic resonance spectroscopy (3 Tesla) in soleus and gastrocnemius. Significantly lower carnosine content (-45%) in gastrocnemius muscle, but not in soleus, was shown in type 2 diabetic patients compared with controls. No differences were observed in type 1 diabetic patients. Type II diabetic patients display a reduced muscular carnosine content. A reduction in muscle carnosine concentration may be partially associated with defective mechanisms against oxidative, glycative and carbonyl stress in muscle
Physiology and pathophysiology of carnosine
No full textCarnosine (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
Correction to: An update on carnosine and anserine research
No full textThe original version of this article unfortunately contained a mistake. The author “Shahid Baba” would like to include the middle name “P” in the online published article.No Full Tex
Late Breaking Abstract - Carnosine and related compounds in m. vastus lateralis of COPD patients: preliminary results
No full textPredicting and testing bioavailability of magnesium supplements
No full textDespite the presumption of the beneficial effects of magnesium supplementation, little is known about the pharmacokinetics of different magnesium formulations. We aimed to investigate the value of two in vitro approaches to predict bioavailability of magnesium and to validate this in subsequent in vivo testing. In vitro assessment of 15 commercially available magnesium formulations was performed by means of a Simulator of the Human Intestinal Microbial Ecosystem (SHIME (R)) and by dissolution tests. Two magnesium formulations with contrasting bioavailability prediction from both in vitro tests (best vs. worst) were selected for in vivo testing in 30 subjects. In vivo bioavailability was compared following one acute ingestion by monitoring blood magnesium concentrations up to 6 h following intake. The in vitro tests showed a very wide variation in absorption and dissolution of the 15 magnesium products. In the in vivo testing, a significant different serum magnesium absorption profile was found up to 4 h following supplement ingestion for the two supplements with opposing in vitro test results. Moreover, maximal serum magnesium increase and total area under the curve were significantly different for both supplements (+6.2% vs. +4.6% and 6.87 vs. 0.31 mM.min, respectively). Collectively, poor bioaccessibility and bioavailability in the SHIME model clearly translated into poor dissolution and poor bioavailability in vivo. This provides a valid methodology for the prediction of in vivo bioavailability and effectiveness of micronutrients by specific in vitro approaches
Personalized Sport and Exercise Nutrition
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
Personalized Sport and Exercise Nutrition
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
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