The carnosine-carnosinase system in relation to diabetes

It is suggested that the molecule carnosine is a potential candidate to counteract the development of diabetes or diabetes-related diseases. This is based on plentiful in vitro studies focusing on its biochemical and physiological protective characteristics. However, up until now the behavior of endogenous carnosine in a diabetic setting is barely known and little in vivo studies are present about the beneficial effects of carnosine supplementation. Therefore, this work contains animal and human data to provide insight into the carnosine metabolism and how it is possibly altered in a diabetic state in rodents and humans; and in vivo evidence about the protective effects of carnosine supplementation in a very mild obese-diabetic rat model. At least an interesting topic and worthwhile to investigate

Influence of combined aerobic and resistance training on metabolic control, cardiovascular fitness and quality of life in adolescents with type 1 diabetes: a randomized controlled trial

OBJECTIVE: To evaluate the effect of combined exercise training on metabolic control, physical fitness and quality of life in adolescents with type 1 diabetes. DESIGN: A double-blind randomized controlled trial with patients receiving combined aerobic and strength or no training. SETTING: University Hospital Ghent (Belgium). SUBJECTS: Sixteen children with type 1 diabetes were randomized into a control group (n = 8) and an intervention group (n = 8). INTERVENTIONS: Patients participated twice a week for 20 weeks in the combined aerobic and strength group. The control group continued their normal daily activities. MAIN MEASURES: Before and after the intervention anthropometric variables (weight, length, BMI, body composition), metabolic control (glycaemia, HbA1c, daily insulin injected), aerobic capacity (peak Vo(2), peak power, peak heart rate, 6-minute walk distance), strength (1 repetition maximum of upper and lower limb, hand grip strength, muscle fatigue resistance, sit-to-stand) and quality of life (SF-36) were assessed. RESULTS: At baseline, none of the measured parameters differed significantly between the two groups. There was no significant evolution in the groups concerning anthropometric indices, glycaemia and HbA1c. However, the daily doses of insulin injected were significantly lowered in the training group (0.96 IU/kg.day pre versus 0.90 IU/kg.day post; P < 0,05), while it was increased in the control group. Physical fitness increased significantly in the training group. General health, vitality and role emotional had a tendency to improve. CONCLUSION: Combined exercise training seemed to lower daily insulin requirement and improve physical fitness, together with better well-being

Physical fitness in morbidly obese patients: effect of gastric bypass surgery and exercise training

Background There is a growing consensus that bariatric surgery is currently the most efficacious and long-term treatment for clinically severe obesity. However, it remains to be determined whether poor physical fitness, an important characteristic of these patients, improves as well. The purpose of this pilot study is to investigate the effect of gastric bypass surgery on physical fitness and to determine if an exercise program in the first 4 months is beneficial. Methods Fifteen morbidly obese patients (BMI 43.0 kg/m(2)) were tested before and 4 months after gastric bypass surgery. Eight of them followed a combined endurance and strength training program. Before and after 4 months the operation, anthropometrical characteristics were measured, and an extensive assessment of physical fitness (strength, aerobic, and functional capacity) was performed. Results Large-scale weight loss through gastric bypass surgery results in a decrease in dynamic and static muscle strength and no improvement of aerobic capacity. In contrast, an intensive exercise program could prevent the decrease and even induced an increase in strength of most muscle groups. Together with an improvement in aerobic capacity, functional capacity increased significantly. Both groups evolved equally with regard to body composition (decrease in fat mass and fat-free mass). Conclusions An exercise training program in the first 4 months after bariatric surgery is effective and should be promoted, considering the fact that physical fitness does not improve by weight loss only

Effect of beta-alanine and carnosine supplementation on muscle contractility in mice

Purpose: Enhanced carnosine levels have been shown to be ergogenic for high-intensity exercise performances, although the role of carnosine in the control of muscle function is poorly understood. Therefore, the aim of this study was to investigate the effect of long-term supplementation with increasing doses of carnosine and beta-alanine on muscle carnosine, anserine, and taurine levels and on in vitro contractility and fatigue in mice. Methods: Male Naval Medical Research Institute mice (n = 66) were control fed or supplemented with either carnosine (0.1%, 0.5%, or 1.8%) or beta-alanine (0.6 or 1.2%) in their drinking water for 8-12 wk. Soleus and extensor digitorum longus (EDL) were tested for in vitro contractile properties, and carnosine, anserine, and taurine content were measured in EDL and tibialis anterior by high-performance liquid chromatography. Results: Only supplementation with 1.8% carnosine and 1.2% beta-alanine resulted in markedly higher carnosine (up to +160%) and anserine levels (up to +46%) compared with control mice. Beta-alanine supplementation (1.2%) resulted in increased fatigue resistance in the beginning of the fatigue protocol in soleus (+2%-4%) and a marked leftward shift of the force-frequency relation in EDL (10%-31% higher relative forces). Conclusion: Comparable with humans, beta-alanine availability seems to be the rate-limiting step for synthesis of muscle histidine-containing dipeptides in mice. Moreover, muscle histidine-containing dipeptides loading in mice moderately and muscle dependently affects excitation-contraction coupling and fatigue

The beta-alanine dose for maintaining moderately elevated muscle carnosine levels

INTRODUCTION: Chronic beta-alanine (BA) supplementation is an increasingly popular nutritional strategy, because it can elevate muscle carnosine content and thereby enhance high-intensity exercise performance. The current study investigates 1) whether sex and body mass are determinants of BA induced muscle carnosine loading, and 2) the optimal maintenance dose for ensuring constantly elevated muscle carnosine stores. METHODS: During the loading phase, 34 participants (men and women) were supplemented with 3.2g (4×800 mg) BA/day for 46 days (slightly different loading strategies were applied concerning the effect of meal-timing and supplementation form). Thereafter, 19 participants (men and women) continued taking free-powder BA for 6 more weeks (maintenance phase). The participants were matched and re-divided into three groups respectively receiving 0.4g BA/day, 0.8g BA/day and 1.2g BA/day. Muscle carnosine content was measured in m. soleus and m. gastrocnemius using H-MRS. RESULTS: Body mass and sex had only minimal effect on the absolute increase in muscle carnosine. Given the lower baseline values of women, the relative increase for women was higher, indicating that women require less BA for the same relative increase. In addition, a significant negative correlation was observed between body mass and the relative increase in muscle carnosine (r=-0.45, p=0.007). A maintenance dose of ∼1.2 g BA/day, was most effective to keep muscle carnosine content elevated at post-supplementation level. CONCLUSION: Sex and body mass do not markedly affect the absolute increase during muscle carnosine loading, although they are determinants for the relative increase. Additionally, we established for the first time an effective maintenance dose of ∼1.2g BA/day to keep muscle carnosine content elevated at 30-50% above baseline for a prolonged period

The influence of combined exercise training on indices of obesity, physical fitness and lipid profile in overweight and obese adolescents with mental retardation

This study investigated the effect of combined exercise training on indices of body composition, physical fitness and lipid profile in adolescents with mental retardation. Thirty adolescents with mental retardation (total IQ, 45-70) received exercise training (n = 15) or no training (n = 15). Groups were matched for age, sex and mental retardation. Before and after the intervention period, indices of body composition, physical fitness and lipid profile were measured. In comparison with the control group, weight, body mass index, waist and fat mass decreased significantly, while relative fat-free mass increased. The level of triglycerides, total cholesterol and low-density lipoprotein decreased significantly, while high-density lipoprotein increased. Muscle strength, muscle fatigue resistance and sit-to-stand were ameliorated. PeakVO2/peak power decreased significantly. The distance covered in the 6-min walk test (6MWT) increased with 50 m. In conclusion, combined exercise training has a positive effect on indices of obesity, physical fitness and lipid profile in adolescents with mental retardation

The effect of combined exercise training in adolescents who are overweight or obese with intellectual disability: the role of training frequency

Data about effects of exercise training in adolescents with intellectual disability (ID) are very limited. This study investigated the effect of 2 different frequencies of the same intensity and total training volume of combined exercise training on indices of body composition, physical fitness, and lipid profile in overweight and obese adolescents with ID. A total of 45 overweight and obese adolescents with ID aged 14-22 years with a total IQ 45-70 received combined exercise training 3 times a week (CET3) for 30 sessions (10 weeks; n = 15), twice a week (CET2) for 30 sessions (15 weeks; n = 15), or no training (10 weeks; n = 15). Groups were matched for age, sex, and education form. Before and after the intervention period, indices of body composition, physical fitness and lipid profile have been evaluated. Compared to the control group, CET3 resulted in a significant improvement of physical fitness, obesity indices, and lipid profile of the participants. Comparing CET2 with CET3, no significantly different evolutions were noticed, except for lower limb strength in favor of exercising 3 times a week. In conclusion, exercising 2 times a week, which is more feasible and practical for participants and guidance, has the same health beneficial effects as 3 times per week in overweight and obese adolescents with ID in short-term training

Plasma carnosine, but not muscle carnosine, attenuates high-fat diet-induced metabolic stress.

There is growing in vivo evidence that the dipeptide carnosine has protective effects in metabolic diseases. A critical unanswered question is whether its site of action is tissues or plasma. This was investigated using oral carnosine versus β-alanine supplementation in a high-fat diet rat model. Thirty-six male Sprague-Dawley rats received a control diet (CON), a high-fat diet (HF; 60% of energy from fat), the HF diet with 1.8% carnosine (HFcar), or the HF diet with 1% β-alanine (HFba), as β-alanine can increase muscle carnosine without increasing plasma carnosine. Insulin sensitivity, inflammatory signaling, and lipoxidative stress were determined in skeletal muscle and blood. In a pilot study, urine was collected. The 3 HF groups were significantly heavier than the CON group. Muscle carnosine concentrations increased equally in the HFcar and HFba groups, while elevated plasma carnosine levels and carnosine-4-hydroxy-2-nonenal adducts were detected only in the HFcar group. Elevated plasma and urine N(ε)-(carboxymethyl)lysine in HF rats was reduced by ∼50% in the HFcar group but not in the HFba group. Likewise, inducible nitric oxide synthase mRNA was decreased by 47% (p < 0.05) in the HFcar group, but not in the HFba group, compared with HF rats. We conclude that plasma carnosine, but not muscle carnosine, is involved in preventing early-stage lipoxidation in the circulation and inflammatory signaling in the muscle of rats