[Show abstract][Hide abstract] ABSTRACT: Metformin (METF), historical antihyperglycemic drug, is a likely candidate for lifespan extension, treatment and prevention of sedentariness damages, insulin resistance, and obesity. Skeletal muscle is a highly adaptable tissue, capable of hypertrophy response to resistance training and of regeneration after damage. Aims of this work were to investigate METF ability to prevent sedentariness damage and to enhance skeletal muscle function. Sedentary 12-week-old C57BL/6 mice were treated with METF (250 mg/kg per day, in drinking water) for 60 days. METF role on skeletal muscle differentiation was studied
using murine C2C12 myoblasts. Muscular performance evaluation revealed that METF enhanced mice physical performance (Estimated
). Biochemical analyses of hepatic and muscular tissues indicated that in liver METF increased AMPK and CAMKII signaling. In contrast, METF inactivated ERKs, the principal kinases involved in hepatic stress. In skeletal muscle, METF activated AKT, key kinase in skeletal muscle mass maintenance. In
studies, METF did not modify the C2C12 proliferation capacity, while it positively influenced the differentiation process and myotube maturation. In conclusion, our novel results suggest that METF has a positive action not only on the promotion of healthy aging but also on the prevention of sedentariness damages.
Full-text · Article · Jan 2016 · Journal of Diabetes Research
[Show abstract][Hide abstract] ABSTRACT: A unifying thread over the wide spectrum of diabetes might be the triggering of innate immunological and inflammatory pathways leading to insulin resistance, beta-cell dysfunction and beta-cell destruction: the hybrid features of type 1 and type 2 diabetes. In fact, hyperglycemia can arise from a deficit in insulin action, insulin secretion, or both. Regularly exercising at moderate intensity has been shown to efficiently and positively impact upon physiological imbalances caused by several morbid conditions. Even in different immunological dysfunctions, physical exercise has been prescribed as a complementary therapeutic strategy. In fact, as suggested by our observations, there is a putative inverse relationship between autoimmunity markers ( GAD, IA) and exercise-derived energy expenditure in type 1 pre-diabetic subjects. Exercise also has been shown to maintain muscle mitochondrial function and thus ability to maintain fuel metabolism and islet cell function. An additional benefit is the enhancement of antioxidant defense system and thus reducing oxidative stress. Therefore, the purpose of this review is to address the importance of physical exercise in a broad range of metabolic disorders that set out a common milieu in which type 1 and type 2 diabetes could be identified as one extensive syndrome.
No preview · Article · Oct 2015 · European review for medical and pharmacological sciences
[Show abstract][Hide abstract] ABSTRACT: The nonobese diabetic (NOD) mouse represents a well-established experimental model analogous to human type 1 diabetes mellitus (T1D) as it is characterized by progressive autoimmune destruction of pancreatic
-cells. Experiments were designed to investigate the impact of moderate-intensity training on T1D immunomodulation and inflammation. Under a chronic exercise regime, NOD mice were trained on a treadmill for 12 weeks (12 m/min for 30 min, 5 d/wk) while age-matched, control animals were left untrained. Prior to and upon completion of the training period, fed plasma glucose and immunological soluble factors were monitored. Both groups showed deteriorated glycemic profiles throughout the study although trained mice tended to be more compensated than controls after 10 weeks of training. An exercise-induced weight loss was detected in the trained mice with respect to the controls from week 6. After 12 weeks, IL-6 and MIP-1
were decreased in the trained animals compared to their baseline values and versus controls, although not significantly. Morphometric analysis of pancreata revealed the presence of larger infiltrates along with decreased
-cells areas in the control mice compared to trained mice. Exercise may exert positive immunomodulation of systemic functions with respect to both T1D and inflammation, but only in a stringent therapeutic window.
Full-text · Article · Sep 2015 · Journal of Diabetes Research
[Show abstract][Hide abstract] ABSTRACT: The targeting of nutraceutical treatment to skeletal muscle damage is an emerging area of research, driven by the need for new therapies for a range of muscle-associated diseases. L-Carnitine (CARN) is an essential nutrient and plays a key role in mitochondrial β-oxidation and in the ubiquitin-proteasome system regulation. As a dietary supplement to improve athletic performance, CARN has been studied for its potential to enhance β-oxidation. However, CARN effects on myogenesis, mitochondrial activity, and hypertrophy process are not completely elucidated. This in vitro study aims to investigate CARN role on skeletal muscle remodeling, differentiation process, and myotubes formation. We analyzed muscle differentiation and morphological features in C2C12 myoblasts exposed to 5 mM CARN. Our results showed that CARN was able to accelerate C2C12 myotubes formation and induce morphological changes, characterizing the start of hypertrophy process. In addition, CARN improved AKT activation and downstream cellular signaling pathways involved in skeletal muscle atrophy process prevention. Also, CARN positively regulated the pathways involved in oxidative stress defense. In this work, we provide an interesting novel mechanism of the potential therapeutic use of CARN to treat pathological conditions characterized by skeletal muscle morphological and functional impairment, oxidative stress production, and atrophy process in aging.
Full-text · Article · Apr 2015 · Oxidative medicine and cellular longevity
[Show abstract][Hide abstract] ABSTRACT: Type 1 diabetes mellitus (T1D), autoimmune thyroid disease, and autoimmune gastritis often occur together forming the so-called autoimmune polyendocrine syndrome type 3 (APS3). We here report a clinical case of a 74-year-old woman who presented for the first time with severe hyperglycemia and ketoacidosis diagnosed as T1D. Further clinical investigations revealed concomitant severe hypothyroidism with autoimmune thyroid disease and severe cobalamin deficiency due to chronic atrophic gastritis. The diagnosis of type 1 diabetes mellitus was confirmed by the detection of autoantibodies against glutamic acid decarboxylase 65, islet cell antibodies, and anti-insulin autoantibodies. Anti-thyroperoxidase, anti-thyroglobulin, and anti-gastric parietal cell antibodies were also clearly positive. The case emphasized that new onset diabetic ketoacidosis, hypothyroidism, and cobalamin deficiency may simultaneously occur, and one disease can mask the features of the other, thereby making diagnosis difficult. It is noteworthy that an APS3 acute episode occurred in an asymptomatic elder woman for any autoimmune diseases.
Full-text · Article · Mar 2015 · Case Reports in Endocrinology
[Show abstract][Hide abstract] ABSTRACT: Diabetes mellitus is a metabolic disease possible to treat via several different therapeutic approaches. Since the advent of insulin in 1922, type 1 diabetes mellitus has become a chronic treatable disease. Nonetheless, type 1 diabetes mellitus can be a devastating disease when the macro- and microangiopathic complications take place after several years of illness. Starting from the eighties, pancreas/islet transplantation has become a potential innovative treatment of diabetes mellitus. The major advantage of pancreas/islet transplantation is the restoration of c-peptide cosecretion along with insulin; the major disadvantage is the need to administer immunosuppressive drugs which are diabetogenic themselves. Islet transplantation is the progenitor of more recent forms of cellular and stem cell therapies which will be reviewed herein. Cellular therapies for diabetes mellitus are still an experimental procedure. Herein we present the actual current achievements and an outlook of close future possible advancements in the area of cellular transplantation for the cure of diabetes mellitus.
[Show abstract][Hide abstract] ABSTRACT: Skeletal muscle regeneration and hypertrophy are important adaptive responses to both physical activity and pathological stimuli. This research was performed to investigate DNA demethylation action on the late phase of muscle differentiation and early stage of hypertrophy. The epigenetic process involved in myogenesis was studied with the DNA-demethylating agent 5-azacytidine (AZA). We induced muscle differentiation in C2C12 mouse myoblasts in the presence of 5 μM AZA and growth or differentiation medium for 48, 72, and 96 h. To study a potential AZA hypertrophic effect, we stimulated 72 h differentiated myotubes with AZA for 24 h. Unstimulated cells were used as control. By western blot and immunofluorescence analysis, we examined AZA action on myogenic regulatory factors expression, hypertrophic signaling pathway and myotube morphology. During differentiation, protein levels of myogenic markers, Myf6 and Myosin Heavy Chain (MyHC), were higher in AZA stimulated cells compared to control. Myostatin and p21 analysis revealed morphological changes which reflect a tendency to hypertrophy in myotubes. In AZA stimulated neo formed myotubes, we observed that IGF-I pathway, kinases p70 S6, 4E-BP1, and ERK1/2 were activated. Furthermore, AZA treatment increased MyHC protein content in stimulated neo myotubes. Our work demonstrates that DNA demethylation could plays an important role in promoting the late phase of myogenesis, activating endocellular pathways involved in protein increment and stimulating the hypertrophic process.
[Show abstract][Hide abstract] ABSTRACT: Nutrigenomics elucidate the ability of bioactive food components to influence gene expression, protein synthesis, degradation and post-translational modifications.Resveratrol (RSV), natural polyphenol found in grapes and in other fruits, has a plethora of health benefits in a variety of human diseases: cardio- and neuroprotection, immune regulation, cancer chemoprevention, DNA repair, prevention of mitochondrial disorder, avoidance of obesity-related diseases. In skeletal muscle, RSV acts on protein catabolism and muscle function, conferring resistance against oxidative stress, injury and cell death, but its action mechanisms and protein targets in myogenesis process are not completely known. Myogenesis is a dynamic multistep process regulated by Myogenic Regulator Factors (MRFs), responsible of the commitment of myogenic cell into skeletal muscle: mononucleated undifferentiated myoblasts break free from cell cycle, elongate and fuse to form multinucleated myotubes. Skeletal muscle hypertrophy can be defined as a result of an increase in the size of pre-existing skeletal muscle fibers accompanied by increased protein synthesis, mainly regulated by Insulin Like Growth Factor 1 (IGF-1), PI3-K/AKT signaling pathways.Aim of this work was the study of RSV effects on proliferation, differentiation process and hypertrophy in C2C12 murine cells.
To study proliferative phase, cells were incubated in growth medium with/without RSV (0.1 or 25 muM) until reaching sub confluence condition (24, 48, 72 h). To examine differentiation, at 70% confluence, cells were transferred in differentiation medium both with/without RSV (0.1 or 25 muM) for 24, 48, 72, 96 hours. After 72 hours of differentiation, the genesis of hypertrophy in neo-formed myotubes was analyzed.
Data showed that RSV regulates cell cycle exit and induces C2C12 muscle differentiation. Furthermore, RSV might control MRFs and muscle-specific proteins synthesis. In late differentiation, RSV has positive effects on hypertrophy: RSV stimulates IGF-1 signaling pathway, in particular AKT and ERK 1/2 protein activation, AMPK protein level and induces hypertrophic morphological changes in neo-formed myotubes modulating cytoskeletal proteins expression.
RSV might control cell cycle promoting myogenesis and hypertrophy in vitro, opening a novel field of application of RSV in clinical conditions characterized by chronic functional and morphological muscle impairment.
Full-text · Article · Dec 2013 · Journal of Translational Medicine
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to compare and validate the use of SenseWear Armband (SWA) placed on the arm (SWA ARM) and on the back (SWA BACK) in healthy humans during resting and a cycle-ergometer exercise and to evaluate the SWA to estimate Resting Energy Expenditure (REE) and Total Energy Expenditure (TEE) in healthy baboons.
We studied 26 (15F/11M) human subjects wearing SWA in two different anatomical sites (arm and back) during resting and a cycle-ergometer test and directly compared these results with indirect calorimetry evaluation (IC), performed at the same time. We then inserted the SWA in a metabolic jacket for baboons and evaluated the TEE and REE in free living condition for 6 days in 21 (8F/13M) non-human primates.
In humans we found a good correlation between SWA place on the ARM and on the BACK with IC during the resting experiment (1.1±0.3 SWAs, 1±0.2 IC kcal/min) and a slight underestimation in the SWAs data compared with IC during the cycle-ergometer exercise (5±1.9 SWA ARM, 4.5±1.5 SWA BACK and 5.4±2.1 IC kcal/min). In the non-human primate (baboons) experiment SWA estimated a TEE of 0.54±0.009 kcal/min during free living and a REE of 0.82±0.06 kcal/min.
SWA, an extremely simple and inexpensive apparatus, provides quite accurate measurements of energy expenditure in humans and in baboons. Energy expenditure data obtained with SWA are highly correlated with the data obtained with "gold standard", IC, in humans.
[Show abstract][Hide abstract] ABSTRACT: Betaine (BET) is a component of many foods, including spinach and wheat. It is an essential osmolyte and a source of methyl groups. Recent studies have hypothesized that BET might play a role in athletic performance. However, BET effects on skeletal muscle differentiation and hypertrophy are still poorly understood.
We examined BET action on neo myotubes maturation and on differentiation process, using C2C12 murine myoblastic cells. We used RT2-PCR array, Western blot and immunofluorescence analysis to study the BET effects on morphological features of C2C12 and on signaling pathways involved in muscle differentiation and hypertrophy.
We performed a dose--response study, establishing that 10 mM BET was the dose able to stimulate morphological changes and hypertrophic process in neo myotubes. RT2-PCR array methodology was used to identify the expression profile of genes encoding proteins involved in IGF-1 pathway. A dose of 10 mM BET was found to promote IGF-1 receptor (IGF-1 R) expression. Western blot and immunofluorescence analysis, performed in neo myotubes, pointed out that 10 mM BET improved IGF-1 signaling, synthesis of Myosin Heavy Chain (MyHC) and neo myotubes length.In addition, we investigated BET role on myoblasts proliferation and differentiation. During proliferation, BET did not modify C2C12 proliferative rate, but promoted myogenic induction, enhancing MyoD protein content and cellular elongation. During differentiation, BET caused an increase of muscle-specific markers and IGF-1 R protein levels.
Our findings provide the first evidence that BET could promote muscle fibers differentiation and increase myotubes size by IGF-1 pathway activation, suggesting that BET might represent a possible new drug/integrator strategy, not only in sport performance but also in clinical conditions characterized by muscle function impairment.
Full-text · Article · Jul 2013 · Journal of Translational Medicine
[Show abstract][Hide abstract] ABSTRACT: Allogeneic islet transplantation (IT) provokes changes in metabolic responses and nutritional behaviors. The durability of these changes needs to be described as well as their impact on the recipients' lifestyle. The goal of this study was to investigate how islet transplantation influenced diet, exercise habits, and body composition during 10 years after IT. A retrospective study performed in 33 (14 males, 19 females) IT recipients used dietary, physical activity open- ended questionnaire and anthropometric measurements. Data were collected before transplantation, every 3 months up to the 18th and every 6 months thereafter. Data were grouped by gender and eras: pre-IT; 0-3 years; 4-6 years, and 7-10 years after IT. Reduction in body mass index (BMI) from pre-IT to 0-3 years was noted: 23.68 ± 2,18 kg/m(2) to 22.07 ± 2.94 kg/m(2) (P < .05). Increased values were observed from 0-3 years to 4-6 years in: waist circumference (WC) (76.68 ± 7.22 to 79.44 ± 7.58 cm), BMI (23,68 ± 2,18 to 22,75 ± 3,11 kg/m(2)) and weight (64.69 ± 11.98 to 67.43 ± 14 kg): (P < .03). WC increased continuously up to 7-10 years (86.33 ± 9.45 cm; P < .05). There was an average of 5.3 ± 5.6 h/wk of exercise during follow-up. From pre-IT to 0-3 years there was a 19% reduction in protein consumption (P < .05) and a 39% increase in calories from saturated fats (P < .05). A trend to reduce carbohydrates intake noted from pre-IT to 0-3 years was progressively inverted from then throughout 7-10 years (not significant). IT was associated with a significantly decreased BMI early on that it was not sustained. The subsequent weight gain and WC increase could be the result of chronic immunosuppressive therapy and/or voluntary change in eating habits. The increased consumption of carbohydrates could be related to an adaptation of a lifestyle or/and reintroduction of insulin after graft dysfunction. Active lifestyle might be result of the intensive clinical care after IT, concomitant awareness of the importance of routine physical exercise on blood glucose control, and diabetes management. Continuous follow-up of IT recipients is needed to better understand these changes and for comparison with subjects with type 1 diabetes mellitus.
No preview · Article · Jun 2013 · Transplantation Proceedings
[Show abstract][Hide abstract] ABSTRACT: Myogenesis is a multistep process, in which myoblasts withdraw from the cell cycle, cease to divide, elongate and fuse to form multinucleated myotubes. Cell cycle transition is controlled by a family of cyclin-dependent protein kinases (CDKs) regulated by association with cyclins, negative regulatory subunits and phosphorylation. Muscle differentiation is orchestrated by myogenic regulatory factors (MRFs), such as MyoD and Myf-5. DNA methylation is crucial in transcriptional control of genes involved in myogenesis. Previous work has indicated that treatment of fibroblasts with the DNA-demethylating agent 5-azacytidine (AZA) promotes MyoD expression. We studied the effects of AZA on cell cycle regulation and MRFs synthesis during myoblast proliferation and early myogenesis phases in C2C12 cells. During the proliferation phase, cells were incubated in growth medium with 5µM AZA (GMAZA) or without AZA (GM) for 24 hours. At 70% confluence, cells were kept in growth medium in order to spontaneously achieve differentiation or transferred to differentiation medium with 5μM AZA (DMAZA) or without AZA (DM) for 12 and 24 hours. Cells used as control were unstimulated.
In the proliferation phase, AZA-treated cells seemed to lose their characteristic circular shape and become elongated. The presence of AZA resulted in significant increases in the protein contents of Cyclin-D (FC:1.23 GMAZA vs GM p≤0.05), p21 (FC: 1.23 GMAZA vs GM p≤0.05), Myf-5 (FC: 1.21 GMAZA vs GM p≤0.05) and MyoD (FC: 1.20 GMAZA vs GM p≤0.05). These results propose that AZA could inhibit cell proliferation.
During 12 hours of differentiation, AZA decreased the downregulation of genes involved in cell cycle arrest and in restriction point (G1 and G1/S phase) and the expression of several cyclins, E2F Transcription Factors, cyclin-dependent kinase inhibitors, specific genes responsible of cell cycle negative regulation. During 24 hours of differentiation, AZA induced an increment in the protein expression of Myf-5 (FC: 1.57 GMAZA vs GM p≤0.05), MyoD (FC: 1.14 DM vs GM p≤0.05; FC: 1.47 DMAZA vs GM p≤0.05), p21 (FC: 1.36 GMAZA vs GM p≤0.01; FC: 1.49 DM vs GM p≤0.05; FC: 1.82 DMAZA vs GM p≤0.01) and MyHC (FC: 1.40 GMAZA vs GM p≤0.01; FC: 2.39 DM vs GM p≤0.05; FC: 3.51 DMAZA vs GM p≤0.01). Our results suggest that AZA-induced DNA demethylation can modulate cell cycle progression and enhance myogenesis. The effects of AZA may open novel clinical uses in the field of muscle injury research and treatment.
Full-text · Article · Apr 2013 · International journal of biological sciences
[Show abstract][Hide abstract] ABSTRACT: Purpose:
It is demonstrated that aerobic exercise plays an important role in weight loss programs for obesity by increasing 24 h metabolic rate. While aerobic exercise can result in health and fitness benefits in obese subjects, also independently of weight loss, not completely clear are the effects of bouts of hard exercise on metabolic outcomes. The aim of this study was to test the hypothesis that short-term aerobic activity with anaerobic bouts might result in a greater improvement in the management of obesity than aerobic activity alone.
We studied 16 obese subjects (eight men) during a progressive cycloergometric test up to exhaustion, before and after 4 weeks of two different training schedules (6 days/week). Insulin and glycaemia, non-esterified fatty acids (NEFA) and lactic acid were sampled. Group A (eight subjects, four men) performed an aerobic cycle workout; Group B (eight subjects, four men) performed a 25 min aerobic workout followed by 5 min of anaerobic workout. All the subjects maintained their individual eating habits.
The post-training test showed a decrease in AUCs NEFA in Group A (p < 0.05) and an increase in Group B (p < 0.05), together with an increase in lactic acid in Group A and a decrease in Group B (p < 0.01). β-cell function (HOMA2-B) revealed a reduction only in Group A (p < 0.05). Group B achieved a greatest reduction in body fat mass than Group A (p < 0.05).
Aerobic plus anaerobic training seem to produce a greater response in lipid metabolism and not significant modifications in glucose indexes; then, in training prescription for obesity, we might suggest at starting weight loss program aerobic with short bouts of anaerobic training to reduce fat mass and subsequently a prolonged aerobic training alone to ameliorate the metabolic profile.
No preview · Article · Apr 2013 · European Journal of Nutrition
[Show abstract][Hide abstract] ABSTRACT: Background
Several studies report martial arts as a good model for investigating neuroendocrine responses to competitive fighting. However, little is known on the metabolic responses elicited by elite athletes during fighting. In particular, the metabolic picture in elite athletes of martial arts is little known.
In the present study, our aim was to investigate the acute effects of a session of karate practice on the glucose-insulin system.
Subjects and methods
Ten healthy individuals (6M/4F; BMI: 22.1 ± 0.7 kg/m2; 21.9 ± 1.1 years, mean ± SE) who practice karate in national or international competitions were enrolled. All participants completed two experimental trials in a randomised-crossover fashion. A basal blood sample was collected from each athlete to assess plasma glucose, insulin, cortisol, testosterone and catecholamines, before karate training session. In two separate days, another blood sample was collected from each participants after 3 min of real fighting (kumite) and 3 min of ritualized simulation of combat (kata).
In both trials, plasma glucose resulted to be higher at the end the of performance compared to the basal (p < 0.001 after kumite and p < 0.02 after kata). In contrast, insulin was similar in the basal and after physical activity in the two trials. Catecholamines were higher after kata and kumite sessions with respect to the basal values (p < 0.04) and, in particular, epinephrine post-kumite values were much greater than those measured after kata.
Our results indicate that unlike performances of karate (kumite and kata) elicit different plasma glucose increases. In particular, we found that glucose and epinephrine concentrations increased more after kumite than after kata.
Full-text · Article · Dec 2012 · Sport Sciences for Health