SUMMARY Little is known about the influence of Myosin Heavy Chain (MHC) isoforms on the contracti... more SUMMARY Little is known about the influence of Myosin Heavy Chain (MHC) isoforms on the contractile properties of single muscle fibres in large animals. We have studied MHC isoform composition and contractile properties of single muscle fibres from the pig. Masseter, diaphragm, longissimus, semitendinosus,rectractor bulbi and rectus lateralis were sampled in female pigs (aged 6 months, mass 160 kg). RT-PCR, histochemistry, immunohistochemistry and gel electrophoresis were combined to identify and separate four MHC isoforms:MHC-slow and three fast MHC (2A, 2X, 2B). Maximum shortening velocity (Vo) and isometric tension(Po) were measured in single muscle fibres with known MHC isoform composition. Six groups of fibres (pure: slow, 2A, 2X and 2B, and hybrid: 2A-2X and 2X-2B) with large differences in Vo and Po were identified. Slow fibres had mean Vo=0.17±0.01 length s-1 and Po=25.1±3.3 mN mm-2. For fast fibres 2A,2X and 2B, mean Vo values were 1.86±0.18,2.55±0.19 and 4.06±0.33 length s...
Rosuvastatin (Rvs) represents one of the most used cholesterol-lowering statins even if its effec... more Rosuvastatin (Rvs) represents one of the most used cholesterol-lowering statins even if its effects may be wider than simply regulation of lipids metabolism [1]. Despite the efficacy in preventing cardiovascular diseases, long-term delivery of statins is associated to adverse effects [2]. So here we studied healthy normotensive mice fed with Rvs at a therapeutic dose (20 mg/kg/day) for one month. To evaluate the influence of dietary essential amino acids mixture (EAAm) in this model, other mice were fed with Rvs and EAAm daily for one month. A normal rodent chow or EAAm supplementation for the same period were further administered in control groups. Ultrastructural analysis of the glomerular filtration barrier did not show any difference between groups. Glomerular area together with mitochondria and lysosomal parameters in renal tubules were evaluated. Moreover we focused on the distribution of chaperones and mitochondria markers (Grp75, Grp78, Bcl2), nitric oxide isoforms (iNOS and...
International Journal of Immunopathology and Pharmacology, 2011
The liver sustains the greatest damage from ethanol (EtOH) abuse. EtOH and its metabolites impair... more The liver sustains the greatest damage from ethanol (EtOH) abuse. EtOH and its metabolites impair hepatocyte metabolism, causing intracellular accumulation of proteins and lipids and increasing radical oxygen species production. These processes are toxic to the mitochondrial respiratory chain and to mitochondrial DNA. We have recently shown that supplementating the diet of rodents with an essential amino acid-enriched mixture (EAAem) significantly increases mitochondrial mass and number in cardiac and skeletal muscles and improves mitochondrial function in aged animals. Thus, in this study we sought to test whether EAAem supplementation could reduce EtOH-induced liver damage. Groups of adult male Wistar rats were fed a standard diet and water ad libitum (the control group), drinking water with 20% EtOH (the EtOH group), or drinking water with 20% EtOH and EAAem supplementation (1.5 g/kg/day) (the EtOH+EAAem group) for 2 months. The blood EtOH concentration was measured, and markers ...
Preclinical or clinical trials for muscular dystrophies have met with modest success, mainly beca... more Preclinical or clinical trials for muscular dystrophies have met with modest success, mainly because of inefficient delivery of viral vectors or donor cells to dystrophic muscles. We report here that intra-arterial delivery of wild-type mesoangioblasts, a class of vessel-associated stem cells, corrects morphologically and functionally the dystrophic phenotype of virtually all downstream muscles in adult immunocompetent α-sarcoglycan (α-SG) null mice, a model organism for limb-girdle muscular dystrophy. When mesoangioblasts isolated from juvenile dystrophic mice and transduced with a lentiviral vector expressing α-SG were injected into the femoral artery of dystrophic mice, they reconstituted skeletal muscle in a manner similar to that seen in wild-type cells. The success of this protocol was mainly due to widespread distribution of donor stem cells through the capillary network, a distinct advantage of this strategy over previous approaches.
Proceedings of the National Academy of Sciences, 2006
Duchenne muscular dystrophy is a relatively common disease that affects skeletal muscle, leading ... more Duchenne muscular dystrophy is a relatively common disease that affects skeletal muscle, leading to progressive paralysis and death. There is currently no resolutive therapy. We have developed a treatment in which we combined the effects of nitric oxide with nonsteroidal antiinflammatory activity by using HCT 1026, a nitric oxide-releasing derivative of flurbiprofen. Here, we report the results of long-term (1-year) oral treatment with HCT 1026 of two murine models for limb girdle and Duchenne muscular dystrophies (α-sarcoglycan-null and mdx mice). In both models, HCT 1026 significantly ameliorated the morphological, biochemical, and functional phenotype in the absence of secondary effects, efficiently slowing down disease progression. HCT 1026 acted by reducing inflammation, preventing muscle damage, and preserving the number and function of satellite cells. HCT 1026 was significantly more effective than the corticosteroid prednisolone, which was analyzed in parallel. As an additio...
We recently generated a mouse model of facioscapulohumeral muscular dystrophy (FSHD) by selective... more We recently generated a mouse model of facioscapulohumeral muscular dystrophy (FSHD) by selectively overexpressing FRG1, a candidate gene for FSHD, in skeletal muscle. The muscles of the FRG-1 mice did not show any plasmamembrane defect suggesting a novel pathogenetic mechanism for FSHD. Here, we study structure and function of muscle fibres from three lines of mice overexpressing FRG1 at different levels: FRG1-low, FRG1-med, FRG1-high. Cross-sectional area (CSA), specific force (Po/CSA) and maximum shortening velocity (V(o)) of identified types of muscle fibres from FRG1-low and FRG1-med mice were analysed and found to be lower than in WT mice. Fast fibres and especially type 2B fibres (the fastest type) were preferentially involved in the dystrophic process showing a much larger force deficit than type 1 (slow) fibres. Consistent with the latter observation, the MHC isoform distribution of several muscles of the three FRG1 lines showed a shift towards slower MHC isoforms in compar...
International journal of sports physical therapy, 2012
Rehabilitation programs for patients with patellofemoral dysfunction aim to recruit the vastus me... more Rehabilitation programs for patients with patellofemoral dysfunction aim to recruit the vastus medialis obliquus muscle (VMO) in an attempt to reduce pain and to improve patellar tracking. The aim of the present study was to use surface EMG to assess the effectiveness of two isometric submaximal contractions (10% and 60% of maximal voluntary contraction, MVC) in promoting preferential activation of VMO over vastus medialis longus (VML) and vastus lateralis (VL) in open and closed kinetic chain isometric exercises with the knee joint fixed at 30, 60 and 90 degrees of flexion. Surface electromyography (EMG) signals were recorded with linear adhesive arrays of four electrodes from fourteen healthy young men (age 23.5±3.2, mean±SD) during isometric knee extension contractions at 10% and 60% of the maximum voluntary contraction (MVC) for 1 min and 20 s respectively at 30, 60 and 90 degrees of knee flexion. Initial values and rate of change (slope) of mean frequency (MNF), average rectifi...
The aging process leads to sarcopenia that is a progressive skeletal muscle weakening due to redu... more The aging process leads to sarcopenia that is a progressive skeletal muscle weakening due to reduction of mass and concomitant change in phenotype. Several studies indicate that amino acids supplementation and, in particular, branched chain amino acids (BCAA) and contraction may activate protein synthesis through the activation of mTOR/ p70S6K signaling pathway. In the present study we used an in vitro assay to analyze the effects of tetanic contractions and acute exposure to branched chain enriched amino acid mixture on mTOR/ p70S6K signaling activation in soleus muscle of elderly rats. Methods: Soleus muscles from Wistar male elderly rats (18 mo of age) were grouped as follows (n = 5 each): nc, not contracted; C, contracted (10 tetani of 0.5 sec/100Hz at 0.02Hz) and contracted and acutely incubated with BCAA enriched mixture at 1% (C+BCAA). Following treatment the activation level of mTOR and p70S6K was measured by Western blot. Results: Contracted muscles (C) showed no increase of mTOR activation relative to uncontracted muscles (nc) and a significant increase of the level of p70S6K activation (+80%). On the contrary following acute BCAA enriched mixture exposure contracted muscles displayed higher mTOR activation (Figure 1) in comparison with C and nc muscles (+40%) and a further increase in p70S6K in comparison with C (+180% vs nc and +55% vs C). Conclusions: Tetanic contractions and acute exposure to BCAA enriched mixture are able to synergically activate the mTOR/p70S6K signalling pathway in the soleus muscle of elderly rats.
Chronic kidney diseases are a social and economic problem, and diet has long been recognized as a... more Chronic kidney diseases are a social and economic problem, and diet has long been recognized as a fundamental modulator of kidney health in human and experimental models. Age-dependent alterations in mitochondrial function play a crucial role in the development of diseases of aging, and mitochondrial disorders have been observed in experimental models of kidney failure. Recently, the beneficial dietary effect of a specific mixture of essential amino acids (EAA) has been studied in elderly subjects, but no data were collected from the kidney. The aim of this study was to assess whether daily supplementation of the diet with EAA at the beginning of senescence could preserve renal health. We used middle-aged (18-month-old) male Wistar rats fed a standard diet and water ad libitum (M-aged group) or a diet with added EAA (1.5 g/kg per day) dissolved in drinking water for 3 months (M-aged+EAA group). Young (2-month-old) rats fed a standard diet for 3 months were used as controls. Mitochondrial morphology and markers for collagen, cyt-c-oxidase, HSP60, GRP75, eNOS, iNOS, Bax, Bcl2 and VEGF were analyzed in glomeruli and tubules. EAA supplementation limited fibrosis and increased the capillary tuft area in the glomeruli of M-aged rats. VEGF and eNOS were enhanced in glomeruli and the peritubular space with the EAA-supplemented diet. Mitochondrial cyt-c oxidase, Bcl2, and chaperones increased in the distal tubules of the EAA group to levels similar to those observed in the young group. Mitochondrial area and density after EAA intake did not differ from young groups. The results suggest that prolonged EAA intake could represent a strategy for maintaining the healthy status of the kidney in M-aged animals.
SUMMARY Little is known about the influence of Myosin Heavy Chain (MHC) isoforms on the contracti... more SUMMARY Little is known about the influence of Myosin Heavy Chain (MHC) isoforms on the contractile properties of single muscle fibres in large animals. We have studied MHC isoform composition and contractile properties of single muscle fibres from the pig. Masseter, diaphragm, longissimus, semitendinosus,rectractor bulbi and rectus lateralis were sampled in female pigs (aged 6 months, mass 160 kg). RT-PCR, histochemistry, immunohistochemistry and gel electrophoresis were combined to identify and separate four MHC isoforms:MHC-slow and three fast MHC (2A, 2X, 2B). Maximum shortening velocity (Vo) and isometric tension(Po) were measured in single muscle fibres with known MHC isoform composition. Six groups of fibres (pure: slow, 2A, 2X and 2B, and hybrid: 2A-2X and 2X-2B) with large differences in Vo and Po were identified. Slow fibres had mean Vo=0.17±0.01 length s-1 and Po=25.1±3.3 mN mm-2. For fast fibres 2A,2X and 2B, mean Vo values were 1.86±0.18,2.55±0.19 and 4.06±0.33 length s...
Rosuvastatin (Rvs) represents one of the most used cholesterol-lowering statins even if its effec... more Rosuvastatin (Rvs) represents one of the most used cholesterol-lowering statins even if its effects may be wider than simply regulation of lipids metabolism [1]. Despite the efficacy in preventing cardiovascular diseases, long-term delivery of statins is associated to adverse effects [2]. So here we studied healthy normotensive mice fed with Rvs at a therapeutic dose (20 mg/kg/day) for one month. To evaluate the influence of dietary essential amino acids mixture (EAAm) in this model, other mice were fed with Rvs and EAAm daily for one month. A normal rodent chow or EAAm supplementation for the same period were further administered in control groups. Ultrastructural analysis of the glomerular filtration barrier did not show any difference between groups. Glomerular area together with mitochondria and lysosomal parameters in renal tubules were evaluated. Moreover we focused on the distribution of chaperones and mitochondria markers (Grp75, Grp78, Bcl2), nitric oxide isoforms (iNOS and...
International Journal of Immunopathology and Pharmacology, 2011
The liver sustains the greatest damage from ethanol (EtOH) abuse. EtOH and its metabolites impair... more The liver sustains the greatest damage from ethanol (EtOH) abuse. EtOH and its metabolites impair hepatocyte metabolism, causing intracellular accumulation of proteins and lipids and increasing radical oxygen species production. These processes are toxic to the mitochondrial respiratory chain and to mitochondrial DNA. We have recently shown that supplementating the diet of rodents with an essential amino acid-enriched mixture (EAAem) significantly increases mitochondrial mass and number in cardiac and skeletal muscles and improves mitochondrial function in aged animals. Thus, in this study we sought to test whether EAAem supplementation could reduce EtOH-induced liver damage. Groups of adult male Wistar rats were fed a standard diet and water ad libitum (the control group), drinking water with 20% EtOH (the EtOH group), or drinking water with 20% EtOH and EAAem supplementation (1.5 g/kg/day) (the EtOH+EAAem group) for 2 months. The blood EtOH concentration was measured, and markers ...
Preclinical or clinical trials for muscular dystrophies have met with modest success, mainly beca... more Preclinical or clinical trials for muscular dystrophies have met with modest success, mainly because of inefficient delivery of viral vectors or donor cells to dystrophic muscles. We report here that intra-arterial delivery of wild-type mesoangioblasts, a class of vessel-associated stem cells, corrects morphologically and functionally the dystrophic phenotype of virtually all downstream muscles in adult immunocompetent α-sarcoglycan (α-SG) null mice, a model organism for limb-girdle muscular dystrophy. When mesoangioblasts isolated from juvenile dystrophic mice and transduced with a lentiviral vector expressing α-SG were injected into the femoral artery of dystrophic mice, they reconstituted skeletal muscle in a manner similar to that seen in wild-type cells. The success of this protocol was mainly due to widespread distribution of donor stem cells through the capillary network, a distinct advantage of this strategy over previous approaches.
Proceedings of the National Academy of Sciences, 2006
Duchenne muscular dystrophy is a relatively common disease that affects skeletal muscle, leading ... more Duchenne muscular dystrophy is a relatively common disease that affects skeletal muscle, leading to progressive paralysis and death. There is currently no resolutive therapy. We have developed a treatment in which we combined the effects of nitric oxide with nonsteroidal antiinflammatory activity by using HCT 1026, a nitric oxide-releasing derivative of flurbiprofen. Here, we report the results of long-term (1-year) oral treatment with HCT 1026 of two murine models for limb girdle and Duchenne muscular dystrophies (α-sarcoglycan-null and mdx mice). In both models, HCT 1026 significantly ameliorated the morphological, biochemical, and functional phenotype in the absence of secondary effects, efficiently slowing down disease progression. HCT 1026 acted by reducing inflammation, preventing muscle damage, and preserving the number and function of satellite cells. HCT 1026 was significantly more effective than the corticosteroid prednisolone, which was analyzed in parallel. As an additio...
We recently generated a mouse model of facioscapulohumeral muscular dystrophy (FSHD) by selective... more We recently generated a mouse model of facioscapulohumeral muscular dystrophy (FSHD) by selectively overexpressing FRG1, a candidate gene for FSHD, in skeletal muscle. The muscles of the FRG-1 mice did not show any plasmamembrane defect suggesting a novel pathogenetic mechanism for FSHD. Here, we study structure and function of muscle fibres from three lines of mice overexpressing FRG1 at different levels: FRG1-low, FRG1-med, FRG1-high. Cross-sectional area (CSA), specific force (Po/CSA) and maximum shortening velocity (V(o)) of identified types of muscle fibres from FRG1-low and FRG1-med mice were analysed and found to be lower than in WT mice. Fast fibres and especially type 2B fibres (the fastest type) were preferentially involved in the dystrophic process showing a much larger force deficit than type 1 (slow) fibres. Consistent with the latter observation, the MHC isoform distribution of several muscles of the three FRG1 lines showed a shift towards slower MHC isoforms in compar...
International journal of sports physical therapy, 2012
Rehabilitation programs for patients with patellofemoral dysfunction aim to recruit the vastus me... more Rehabilitation programs for patients with patellofemoral dysfunction aim to recruit the vastus medialis obliquus muscle (VMO) in an attempt to reduce pain and to improve patellar tracking. The aim of the present study was to use surface EMG to assess the effectiveness of two isometric submaximal contractions (10% and 60% of maximal voluntary contraction, MVC) in promoting preferential activation of VMO over vastus medialis longus (VML) and vastus lateralis (VL) in open and closed kinetic chain isometric exercises with the knee joint fixed at 30, 60 and 90 degrees of flexion. Surface electromyography (EMG) signals were recorded with linear adhesive arrays of four electrodes from fourteen healthy young men (age 23.5±3.2, mean±SD) during isometric knee extension contractions at 10% and 60% of the maximum voluntary contraction (MVC) for 1 min and 20 s respectively at 30, 60 and 90 degrees of knee flexion. Initial values and rate of change (slope) of mean frequency (MNF), average rectifi...
The aging process leads to sarcopenia that is a progressive skeletal muscle weakening due to redu... more The aging process leads to sarcopenia that is a progressive skeletal muscle weakening due to reduction of mass and concomitant change in phenotype. Several studies indicate that amino acids supplementation and, in particular, branched chain amino acids (BCAA) and contraction may activate protein synthesis through the activation of mTOR/ p70S6K signaling pathway. In the present study we used an in vitro assay to analyze the effects of tetanic contractions and acute exposure to branched chain enriched amino acid mixture on mTOR/ p70S6K signaling activation in soleus muscle of elderly rats. Methods: Soleus muscles from Wistar male elderly rats (18 mo of age) were grouped as follows (n = 5 each): nc, not contracted; C, contracted (10 tetani of 0.5 sec/100Hz at 0.02Hz) and contracted and acutely incubated with BCAA enriched mixture at 1% (C+BCAA). Following treatment the activation level of mTOR and p70S6K was measured by Western blot. Results: Contracted muscles (C) showed no increase of mTOR activation relative to uncontracted muscles (nc) and a significant increase of the level of p70S6K activation (+80%). On the contrary following acute BCAA enriched mixture exposure contracted muscles displayed higher mTOR activation (Figure 1) in comparison with C and nc muscles (+40%) and a further increase in p70S6K in comparison with C (+180% vs nc and +55% vs C). Conclusions: Tetanic contractions and acute exposure to BCAA enriched mixture are able to synergically activate the mTOR/p70S6K signalling pathway in the soleus muscle of elderly rats.
Chronic kidney diseases are a social and economic problem, and diet has long been recognized as a... more Chronic kidney diseases are a social and economic problem, and diet has long been recognized as a fundamental modulator of kidney health in human and experimental models. Age-dependent alterations in mitochondrial function play a crucial role in the development of diseases of aging, and mitochondrial disorders have been observed in experimental models of kidney failure. Recently, the beneficial dietary effect of a specific mixture of essential amino acids (EAA) has been studied in elderly subjects, but no data were collected from the kidney. The aim of this study was to assess whether daily supplementation of the diet with EAA at the beginning of senescence could preserve renal health. We used middle-aged (18-month-old) male Wistar rats fed a standard diet and water ad libitum (M-aged group) or a diet with added EAA (1.5 g/kg per day) dissolved in drinking water for 3 months (M-aged+EAA group). Young (2-month-old) rats fed a standard diet for 3 months were used as controls. Mitochondrial morphology and markers for collagen, cyt-c-oxidase, HSP60, GRP75, eNOS, iNOS, Bax, Bcl2 and VEGF were analyzed in glomeruli and tubules. EAA supplementation limited fibrosis and increased the capillary tuft area in the glomeruli of M-aged rats. VEGF and eNOS were enhanced in glomeruli and the peritubular space with the EAA-supplemented diet. Mitochondrial cyt-c oxidase, Bcl2, and chaperones increased in the distal tubules of the EAA group to levels similar to those observed in the young group. Mitochondrial area and density after EAA intake did not differ from young groups. The results suggest that prolonged EAA intake could represent a strategy for maintaining the healthy status of the kidney in M-aged animals.
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