Muscle Carnosine Is Associated with Cardiometabolic Risk Factors in Humans

Background Carnosine is a naturally present dipeptide abundant in skeletal muscle and an over-the counter food additive. Animal data suggest a role of carnosine supplementation in the prevention and treatment of obesity, insulin resistance, type 2 diabetes and cardiovascular disease but only limited human data exists. Methods and Results Samples of vastus lateralis muscle were obtained by needle biopsy. We measured muscle carnosine levels (high-performance liquid chromatography), % body fat (bioimpedance), abdominal subcutaneous and visceral adiposity (magnetic resonance imaging), insulin sensitivity (euglycaemic hyperinsulinemic clamp), resting energy expenditure (REE, indirect calorimetry), free-living ambulatory physical activity (accelerometers) and lipid profile in 36 sedentary non-vegetarian middle aged men (45±7 years) with varying degrees of adiposity and glucose tolerance. Muscle carnosine content was positively related to % body fat (r = 0.35, p = 0.04) and subcutaneous (r = 0.38, p = 0.02) but not visceral fat (r = 0.17, p = 0.33). Muscle carnosine content was inversely associated with insulin sensitivity (r = -0.44, p = 0.008), REE (r = -0.58, p<0.001) and HDL-cholesterol levels (r = -0.34, p = 0.048). Insulin sensitivity and physical activity were the best predictors of muscle carnosine content after adjustment for adiposity. Conclusion Our data shows that higher carnosine content in human skeletal muscle is positively associated with insulin resistance and fasting metabolic preference for glucose. Moreover, it is negatively associated with HDL-cholesterol and basal energy expenditure. Intervention studies targeting insulin resistance, metabolic and cardiovascular disease risk factors are necessary to evaluate its putative role in the prevention and management of type 2 diabetes and cardiovascular disease

Author Correction: Effect of carnosine supplementation on the plasma lipidome in overweight and obese adults: a pilot randomised controlled trial

This is a corrigendum for the article of the same title, published in Scientific Reports (2017) 7/1 https://doi.org/10.1038/s41598-017-17577-

Carnosine supplementation improves serum resistin concentrations in overweight or obese otherwise healthy adults: A pilot randomized trial

Adipokines play an important role in the regulation of glucose metabolism. We have previously shown that carnosine supplementation in overweight or obese non-diabetic individuals improves glucose metabolism but does not change adiponectin concentrations. However, its effect on other adipokines has not been investigated. Herein we further determined the effect of carnosine supplementation on serum adipsin, resistin and leptin. Twenty-two overweight or obese otherwise healthy adults were randomly assigned to receive either 2 g of carnosine (n = 13) or identically looking placebo (n = 9) for 12 weeks. Serum adipsin, leptin and resistin were analyzed using a bead-based multiplex assay. Carnosine supplementation decreased serum resistin concentrations compared to placebo (mean change from baseline: -35 ± 83 carnosine vs. 35 ± 55 ng/mL placebo, p = 0.04). There was a trend for a reduction in serum leptin concentrations after carnosine supplementation (-76 ± 165 ng/mL carnosine vs. 20 ± 28 ng/mL placebo, p = 0.06). The changes in leptin and resistin concentrations were inversely related to the change in concentration for urinary carnosine (r = -0.72, p = 0.0002; r = -0.67, p = 0.0009, respectively), carnosine-propanal (r = -0.56, p = 0.005; r = -0.63, p = 0.001, respectively) and carnosine-propanol (r = -0.61, p = 0.002; r = -0.60, p = 0.002, respectively). There were no differences between groups in change in adipsin concentrations. Our findings show carnosine supplementation may normalize some, but not all, of the serum adipokine concentrations involved in glucose metabolism, in overweight and obese individuals. Further clinical trials with larger samples are needed to confirm these results

Inflammatory and other biomarkers: role in pathophysiology and prediction of gestational diabetes mellitus

Understanding pathophysiology and identifying mothers at risk of major pregnancy complications is vital to effective prevention and optimal management. However, in current antenatal care, understanding of pathophysiology of complications is limited. In gestational diabetes mellitus (GDM), risk prediction is mostly based on maternal history and clinical risk factors and may not optimally identify high risk pregnancies. Hence, universal screening is widely recommended. Here, we will explore the literature on GDM and biomarkers including inflammatory markers, adipokines, endothelial function and lipids to advance understanding of pathophysiology and explore risk prediction, with a goal to guide prevention and treatment of GDM.Sally K. Abell, Barbora De Courten, Jacqueline A. Boyle and Helena J. Teed

Prevalence, clustering and sociodemographic distributions of non-communicable disease risk factors in Nepalese adolescents: secondary analysis of a nationwide school survey

OBJECTIVES: To assess the prevalence, clustering and sociodemographic distribution of non-communicable disease (NCD) risk factors in adolescents in Nepal. DESIGN: Data originated from Global School Based Student Health Survey, Nepal conducted in 2015-2016. SETTING: The study sites were the secondary schools in Nepal; 74 schools were selected based on the probability proportional to school enrolment size throughout Nepal. PARTICIPANTS: 5795 school-going children aged 13-17 years were included in the study. PRIMARY OUTCOMES: NCD risk factors: smoking, alcohol consumption, insufficient fruit and vegetable intake, insufficient physical activity and overweight/obesity were the primary outcomes. Sociodemographic distributions of the combined and individual NCD risk factors were determined by Poisson regression analysis. RESULTS: Findings revealed the prevalence of smoking (6.04%; CI 4.62 to 7.88), alcohol consumption (5.29%; CI 4.03 to 6.92), insufficient fruit and vegetable intake (95.33%; CI 93.89 to 96.45), insufficiently physical activity (84.77%; CI 81.04 to 87.88) and overweight/obesity (6.66%; CI 4.65 to 9.45). One or more risk factors were present in 99.6%, ≥2 were in 83% and ≥3 were in 11.2%. Risk factors were more likely to cluster in male, 17 years of age and grade 7. Prevalence of smoking (adjusted prevalence ratio (aPR)=2.38; CI 1.6 to 3.51) and alcohol consumption (aPR=1.81; CI 1.29 to 2.53) was significantly high in male, and in 16 and 17 years of age. Prevalence of insufficient physical activity and overweight/obesity was significantly lower in higher grades. CONCLUSION: Insufficient fruit and vegetable intake and insufficient physical activity were highly prevalent in the populations studied. Risk factors were disproportionately distributed and clustered in particular gender, age and grade. The study population requires an age and gender specific preventive public health intervention

Effect of carnosine supplementation on the plasma lipidome in overweight and obese adults: a pilot randomised controlled trial

Correction/corrigendum to this article published: Baye, E., Ukropec, J., de Courten, M.P.J. et al. Author Correction: Effect of carnosine supplementation on the plasma lipidome in overweight and obese adults: a pilot randomised controlled trial. Sci Rep 10, 4384 (2020). https://doi.org/10.1038/s41598-020-61335-

Supplementation-Induced Change in Muscle Carnosine is Paralleled by Changes in Muscle Metabolism, Protein Glycation and Reactive Carbonyl Species Sequestering

Carnosine is a performance-enhancing food supplement with a potential to modulate muscle energy metabolism and toxic metabolites disposal. In this study we explored interrelations between carnosine supplementation (2 g/day, 12 weeks) induced effects on carnosine muscle loading and parallel changes in (i) muscle energy metabolism, (ii) serum albumin glycation and (iii) reactive carbonyl species sequestering in twelve (M/F=10/2) sedentary, overweight-to-obese (BMI: 30.0 +/- 2.7 kg/m2) adults (40.1 +/- 6.2 years). Muscle carnosine concentration (Proton Magnetic Resonance Spectroscopy; 1H-MRS), dynamics of muscle energy metabolism (Phosphorus Magnetic Resonance Spectroscopy; 31P-MRS), body composition (Magnetic Resonance Imaging; MRI), resting energy expenditure (indirect calorimetry), glucose tolerance (oGTT), habitual physical activity (accelerometers), serum carnosine and carnosinase-1 content/activity (ELISA), albumin glycation, urinary carnosine and carnosine-propanal concentration (mass spectrometry) were measured. Supplementation-induced increase in muscle carnosine was paralleled by improved dynamics of muscle post-exercise phosphocreatine recovery, decreased serum albumin glycation and enhanced urinary carnosine-propanal excretion (all p&lt;0.05). Magnitude of supplementation-induced muscle carnosine accumulation was higher in individuals with lower baseline muscle carnosine, who had lower BMI, higher physical activity level, lower resting intramuscular pH, but similar muscle mass and dietary protein preference. Level of supplementation-induced increase in muscle carnosine correlated with reduction of protein glycation, increase in reactive carbonyl species sequestering, and acceleration of muscle post-exercise phosphocreatine recovery