Search results for "skeletal muscle"

Towards powerful old age : association between hormone replacement therapy and skeletal muscle

2010

Aged Nicotinamide Riboside Kinase 2 Deficient Mice Present an Altered Response to Endurance Exercise Training

2018

Background: Skeletal muscle aging is marked by the development of a sarcopenic phenotype, a global decline of muscle energetic capacities, and an intolerance to exercise. Among the metabolic disorders involved in this syndrome, NAD metabolism was shown to be altered in skeletalmuscle, with an important role for the NAMPT enzyme recycling the nicotinamide precursor. An alternative pathway for NAD biosynthesis has been described for the nicotinamide riboside vitamin B3 precursor used by the NMRK kinases, including the striated muscle-specific NMRK2.Aim: With this study, our goal is to explore the ability of 16-month-old Nmrk2−/− mice to perform endurance exercise and study the consequences on…

Normal weight obesity and physical fitness in Chinese university students: an overlooked association

2018

Background: The primary aim of this study was to examine the associations of normal weight obesity (NWO) with physical fitness in Chinese university students. As a secondary aim, we assessed whether possible differences in physical fitness between students classified as NWO and normal weight non-obese (NWNO) were mediated by skeletal muscles mass. Methods: A total of 383 students (205 males and 178 females, aged 18–24 years) from two universities volunteered to participate in this study. Body height and weight were measured by standard procedures and body composition was assessed by bio-impedance analysis (InBody 720). NWO was defined by a BMI of 18.5–23.9 kg/m2 and a body fat percentage of…

Global gene expression profiles in skeletal muscle of monozygotic female twins discordant for hormone replacement therapy

2010

Aging is accompanied by inexorable loss of muscle tissue. One of the underlying causes for this is the massive change in the hormonal milieu of the body. The role of a female sex steroid – estrogen – in these processes is frequently neglected, although the rapid decline in its production coincides with a steep deterioration in muscle performance. We recruited 54- to 62-year-old monozygotic female twin pairs discordant for postmenopausal hormone replacement therapy (HRT, n = 11 pairs; HRT use 7.3 ± 3.7 years) from the Finnish Twin Cohort to investigate the association of long-term, estrogen-based HRT with skeletal muscle transcriptome. Pathway analysis of muscle transcript profiles revealed …

Are skeletal muscle FNDC5 expression and irisin release regulated by exercise and related to health?

2013

Recently, contradictory findings have been reported concerning the function of irisin and its precursor gene, skeletal muscle FNDC5, in energy homeostasis, and the associated regulatory role of exercise and PGC-1α. We therefore evaluated whether muscle FNDC5 mRNA and serum irisin are exercise responsive and whether PGC-1α expression is associated with FNDC5 expression. The male subjects in the study performed single exercises: (1) 1 h low-intensity aerobic exercise (AE) (middle-aged, n= 17), (2) a heavy-intensity resistance exercise (RE) bout (young n= 10, older n= 11) (27 vs. 62 years), (3) long-term 21 weeks endurance exercise (EE) training alone (twice a week, middle-aged, n= 9), or (4) …

Increased autophagy and apoptosis contribute to muscle atrophy in a myotonic dystrophy type 1 Drosophila model

2015

ABSTRACT Muscle mass wasting is one of the most debilitating symptoms of myotonic dystrophy type 1 (DM1) disease, ultimately leading to immobility, respiratory defects, dysarthria, dysphagia and death in advanced stages of the disease. In order to study the molecular mechanisms leading to the degenerative loss of adult muscle tissue in DM1, we generated an inducible Drosophila model of expanded CTG trinucleotide repeat toxicity that resembles an adult-onset form of the disease. Heat-shock induced expression of 480 CUG repeats in adult flies resulted in a reduction in the area of the indirect flight muscles. In these model flies, reduction of muscle area was concomitant with increased apopto…

Effects of Long-Term Physical Activity and BCAA Availability on the Subcellular Associations between Intramyocellular Lipids, Perilipins and PGC-1&al…

2023

Cellular skeletal muscle lipid metabolism is of paramount importance for metabolic health, specifically through its connection to branched-chain amino acids (BCAA) metabolism and through its modulation by exercise. In this study, we aimed at better understanding intramyocellular lipids (IMCL) and their related key proteins in response to physical activity and BCAA deprivation. By means of confocal microscopy, we examined IMCL and the lipid droplet coating proteins PLIN2 and PLIN5 in human twin pairs discordant for physical activity. Additionally, in order to study IMCLs, PLINs and their association to peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) in cytosolic…

Hsp60 in Skeletal Muscle: From Molecular Anatomy to Pathophysiology

2019

The chaperoning system of an organism is composed of the entire set of chaperones, co-chaperones, and chaperone co-factors and their interactors and receptors. Its functions pertain typically to protein homeostasis but also to many other activities inside and outside cells. In the skeletal muscle, with its multi-molecular structures rich in proteins and their continuous rearrangements, the chaperoning system plays a crucial role. However, little is known about the details of the workings of the chaperoning system in skeletal muscle development and during exercise and disease. Molecular chaperones are surely involved in muscle formation and maintenance under physiologic conditions and under …

Activity of acid hydrolases in skeletal muscle of untrained, trained and detrained mice of different ages.

1978

The activities of p-nitrophenylphosphatase, beta-glucuronidase and beta-N-acetylglucosaminidase from crude skeletal muscle homogenates of 4 and 7 months old mice were assayed after short-term intensive and long-term moderate training and after terminated training. In the older untrained mice the activity of the hydrolases was higher than in the younger mice. The level increased with training and this increase was far more pronounced in the older animals. Cessation of training for 7 and 21 days decreased this activity in the older animals but it was again increased 42 days later and close to the level observed in the trained mice. In young mice 3 days' terminated training increased the activ…

Effect of Physical Training on Enzyme Activities of Bones, Tendons and Skeletal Muscles in Mice

1975

According to several recent papers the activity of some enzymes of energy yielding metabolic pathways increases by endurance training in muscles, but it is not yet known whether similar changes occur also in connective tissues. Some structural, chemical, physical and metabolic changes, however, appear in connective tissues during adaptation to physical exercise. Physical training produces hypertrophy of e.g. tendon and articular cartilage in young rabbits [6] and increases the tensile strength of tendons and breaking strength of bones in growing mice [7]. The level of physical activity affects the turnover of collagen in long bones and Achilles tendons of mice [4] and also affects the miner…