Search results for "MUSCLE ATROPHY"
showing 10 items of 47 documents
Morphological Evidence of Telocytes in Skeletal Muscle Interstitium of Exercised and Sedentary Rodents
2021
Skeletal muscle atrophy, resulting from states of hypokinesis or immobilization, leads to morphological, metabolic, and functional changes within the muscle tissue, a large variety of which are supported by the stromal cells populating the interstitium. Telocytes represent a recently discovered population of stromal cells, which has been increasingly identified in several human organs and appears to participate in sustaining cross-talk, promoting regenerative mechanisms and supporting differentiation of local stem cell niche. The aim of this morphologic study was to investigate the presence of Telocytes in the tibialis anterior muscle of healthy rats undergoing an endurance training protoco…
Inhibition of autophagy rescues muscle atrophy in a LGMDD2 Drosophila model
2021
Limb-girdle muscular dystrophy D2 (LGMDD2) is an ultrarare autosomal dominant myopathy caused by mutation of the normal stop codon of the TNPO3 nuclear importin. The mutant protein carries a 15 amino acid C-terminal extension associated with pathogenicity. Here we report the first animal model of the disease by expressing the human mutant TNPO3 gene in Drosophila musculature or motor neurons and concomitantly silencing the endogenous expression of the fly protein ortholog. A similar genotype expressing wildtype TNPO3 served as a control. Phenotypes characterization revealed that mutant TNPO3 expression targeted at muscles or motor neurons caused LGMDD2-like phenotypes such as muscle degener…
Abnormalities of mitochondrial functioning can partly explain the metabolic disorders encountered in sarcopenic gastrocnemius.
2007
International audience; Aging triggers several abnormalities in muscle glycolytic fibers including increased proteolysis, reactive oxygen species (ROS) production and apoptosis. Since the mitochondria are the main site of substrate oxidation, ROS production and programmed cell death, we tried to know whether the cellular disorders encountered in sarcopenia are due to abnormal mitochondrial functioning. Gastrocnemius mitochondria were extracted from adult (6 months) and aged (21 months) male Wistar rats. Respiration parameters, opening of the permeability transition pore and ROS production, with either glutamate (amino acid metabolism) or pyruvate (glucose metabolism) as a respiration substr…
Decreased motor unit firing rate and force control in older men
2006
Introduction Ageing is related to muscle atrophy that leads to decreases in muscle force. The largest changes are found in fast muscle fibres and fast force production, reducing the capability to recover from sudden balance disturbances. Also ageing-related decrease in force control has been found, as indicated by an increase in force fluctuations and motor unit (MU) firing variability (Galganski et al. 1993). Possibly due to differences in measurement protocols and muscles, the results concerning the effects of ageing on motor unit firing rate are, however, somewhat contradictory (for review, see Roos et al. 1997). The purpose of the present study was to investigate the age-related changes…
Effect of Electrical Stimulation on Denervated Muscle
1986
The possibilities of noninvasive treatment in peripheral nerve injuries are limited. Although it is well known that the severance of a nerve results in paralysis of the dependent tissue, the methods of treating a denervated muscle are still controversial. The most obvious result of denervation is muscle atrophy and paralysis. In 1841 Reid forced the denervated muscle to contract by electrical stimulation to replace the loss of activity and observed that this treatment retarded atrophy. Since then, there has been continuing interest in preventing muscle atrophy with electrotherapy. Peripheral nerve injuries in the two world wars were, for instance, extensively treated with electrical stimula…
miR-7 Restores Phenotypes in Myotonic Dystrophy Muscle Cells by Repressing Hyperactivated Autophagy
2019
International audience; Unstable CTG expansions in the 3' UTR of the DMPK gene are responsible for myotonic dystrophy type 1 (DM1) condition. Muscle dysfunction is one of the main contributors to DM1 mortality and morbidity. Pathways by which mutant DMPK trigger muscle defects, however, are not fully understood. We previously reported that miR-7 was downregulated in a DM1 Drosophila model and in biopsies from patients. Here, using DM1 and normal muscle cells, we investigated whether miR-7 contributes to the muscle phenotype by studying the consequences of replenishing or blocking miR-7, respectively. Restoration of miR-7 with agomiR-7 was sufficient to rescue DM1 myoblast fusion defects and…
Effects of fasting on skeletal muscles and body fat of adult and old C57BL/6J mice
2021
Fasting improves metabolic health, but is also associated with loss of lean body mass. We investigated if old mice are less resistant to fasting-induce muscle wasting than adult mice. We compared changes in skeletal muscles and fat distribution in C57BL/6J mice subjected to 48-hour fasting at adult (6-month old) or old (24-month old) age. Old mice lost less weight (11.9 ± 1.5 vs 16.9 ± 2.8%, p 0.001) and showed less (p 0.01) pronounced muscle wasting than adult mice. Extensor digitorum longus (EDL) muscle force decreased only in adult mice after fasting. Serum IGF-1 levels were higher (p 0.01) and showed greater (p 0.01) decline in adult mice compared to old mice. Phosphorylation of 4EB…
OGT and OGA expression in postmenopausal skeletal muscle associates with hormone replacement therapy and muscle cross-sectional area
2013
Protein glycosylation via O-linked N-acetylglucosaminylation (O-GlcNAcylation) is an important post-translational regulatory mechanism mediated by O-GlcNAc transferase (OGT) and responsive to nutrients and stress. OGT attaches an O-GlcNAc moiety to proteins, while O-GlcNAcase (OGA) catalyzes O-GlcNAc removal. In skeletal muscle of experimental animals, prolonged increase in O-GlcNAcylation associates with age and muscle atrophy. Here we examined the effects of hormone replacement therapy (HRT) and power training (PT) on muscle OGT and OGA gene expression in postmenopausal women generally prone to age-related muscle weakness. In addition, the associations of OGT and OGA gene expressions with…
Treatment of sarcopenia by targeting Akt and muscle specific ubiquitin ligases. Evidence from mice and from a clinical trial
2017
Disuse muscle wasting may take place as a result of several such as joint immobilization, inactivity or bed rest. There are no good therapies to treat it. Allopurinol, a drug commonly used to treat hyperuricemia and gout, protects muscle damage, specially after exhaustive exercise and results in functional gains in old persons. Thus, we tested its effect in the prevention of atrophy of the soleus muscle after two weeks of hindlimb unloading in experimental animals (mice), and lower leg immobilization following ankle sprain in humans (Registration of the clinical Trial: EUDRACT2011-003541-17). We have found show that allopurinol protects against muscle atrophy in both mice and humans. The pr…
Prolonged exposure to microgravity modifies limb endpoint kinematics during the swing phase of human walking
2002
Many neurophysiological and behavioural studies suggested that the lower limb endpoint might be a centrally represented variable within the gravity reference frame and effectively controlled during the locomotion. This investigation examines the effects of prolonged exposure to microgravity upon lower limb endpoint kinematics. Seven cosmonauts were tested before and the 2nd day after a 6 month orbital mission. The spatio-temporal patterns of the limb extremity (malleolus) were analysed during the swing phase of the walk using a motion analysis system. Paths and velocity profiles of endpoint displacements were computed and compared for both the pre- and post-flight walking sessions. The resu…