Search results for "skeletal muscle"

Muscle performance, sex hormones and training in peri-menopausal and post-menopausal women

2003

Age-related deterioration in muscle performance is one of the major reasons for decreased functional capacity and disability in older people. In women, impaired muscle performance has already been observed during peri-menopause in concert with rapid and dramatic decrease in ovarian hormone production. This observation suggests that female sex steroids may have an important role among other agents in regulating muscle performance in middle-aged and older women. Previous experimental studies have shown that hormone replacement therapy (HRT) and intensive physical training have positive effects on muscle force and explosive power in healthy post-menopausal women. Hormone replacement therapy in…

Assessment of Skeletal Muscle Microperfusion Using MRI

2013

Blood oxygenation level-dependent (BOLD) MRI, arterial spin labeling (ASL) and dynamic contrast enhancement (DCE) are current magnetic resonance imaging (MRI) techniques allowing the non-invasive functional assessment of peripheral microvasculature in healthy and diseased individuals. The functional imaging of skeletal muscle microvasculature helps to understand muscular and vascular physiology and alterations of microcirculation under certain pathological conditions such as peripheral arterial occlusive disease, diabetes mellitus, chronic compartment syndrome and rheumatic disorders. BOLD MRI uses blood as an endogenous contrast agent provided by the different magnetic properties of oxy- a…

Catechol-O-Methyltransferase Gene Polymorphism Is Associated with Skeletal Muscle Properties in Older Women Alone and Together with Physical Activity

2008

BackgroundMuscle strength declines on average by one percent annually from midlife on. In postmenopausal women this decrement coincides with a rapid decline in estrogen production. The genetics underlying the effects of estrogen on skeletal muscle remains unclear. In the present study, we examined whether polymorphisms within COMT and ESR1 are associated with muscle properties and assessed their interaction and their combined effects with physical activity.Methodology/principal findingsA cross-sectional data analysis was conducted with 434 63-76-year-old women from the population-based Finnish Twin Study on Aging. Body anthropometry, muscle cross-sectional area (mCSA), isometric hand grip a…

Hormone Replacement Therapy Associated White Blood Cell DNA Methylation and Gene Expression are Associated With Within-Pair Differences of Body Adipo…

2015

The loss of estrogen during menopause causes changes in the female body, with wide-ranging effects on health. Estrogen-containing hormone replacement therapy (HRT) leads to a relief of typical menopausal symptoms, benefits bone and muscle health, and is associated with tissue-specific gene expression profiles. As gene expression is controlled by epigenetic factors (including DNA methylation), many of which are environmentally sensitive, it is plausible that at least part of the HRT-associated gene expression is due to changes in DNA methylation profile. We investigated genome-wide DNA methylation and gene expression patterns of white blood cells (WBCs) and their associations with body compo…

Physical Exercise Increases mRNA Levels of Fibrillar Collagen Types I and Iii and α-Subunit of Prolyl 4-Hydroxylase in Rat Skeletal Muscle

1994

Gene expression centroids that link with low intrinsic aerobic exercise capacity and complex disease risk

2010

A strong link exists between low aerobic exercise capacity and complex metabolic diseases. To probe this linkage, we utilized rat models of low and high intrinsic aerobic endurance running capacity that differ also in the risk for metabolic syndrome. We investigated in skeletal muscle gene-phenotype relationships that connect aerobic endurance capacity with metabolic disease risk factors. The study compared 12 high capacity runners (HCRs) and 12 low capacity runners (LCRs) from generation 18 of selection that differed by 615% for maximal treadmill endurance running capacity. On average, LCRs were heavier and had increased blood glucose, insulin, and triglycerides compared with HCRs. HCRs we…

Branched-Chain Amino Acid Deprivation Decreases Lipid Oxidation and Lipogenesis in C2C12 Myotubes

2022

Impaired lipid metabolism is a common risk factor underlying several metabolic diseases such as metabolic syndrome and type 2 diabetes. Branched-chain amino acids (BCAAs) that include valine, leucine and isoleucine have been proven to share a role in lipid metabolism and hence in maintaining metabolic health. We have previously introduced a hypothesis suggesting that BCAA degradation mechanistically connects to lipid oxidation and storage in skeletal muscle. To test our hypothesis, the present study examined the effects of BCAA deprivation and supplementation on lipid oxidation, lipogenesis and lipid droplet characteristics in murine C2C12 myotubes. In addition, the role of myotube contract…

Intramyocellular topography of lipid droplets and OXPAT in obesity and type II diabetes

2010

Nowadays in the westernized world, high caloric diet and sedentarism are driving populations to accumulate ectopic fat, especially in skeletal muscle. Such is associated with the development of insulin resistance (IR) related metabolic diseases, as type II diabetes (T2D) and obesity (OB). Like IR individuals, athletes also show high intramyocellular lipids (IMCL) contents, denoting qualitative rather than quantitative differences between insulin sensitive (IS) and IR individuals IMCL. PAT proteins and OXPAT specifically, are among the main regulators of lipid droplets (LDs) in skeletal muscle. We hypothesized that different IS profiles are distinguishable through LD and OXPAT localization a…

Effects of high-fat diet and physical activity on pyruvate dehydrogenase kinase-4 in mouse skeletal muscle

2012

Background. The expression of PDK4 is elevated by diabetes, fasting and other conditions associated with the switch from the utilization of glucose to fatty acids as an energy source. It is previously shown that peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a master regulator of energy metabolism, coactivates in cell lines pyruvate dehydrogenase kinase-4 (PDK4) gene expression via the estrogen-related receptor α (ERRα). We investigated the effects of long-term high-fat diet and physical activity on the expression of PDK4, PGC-1α and ERRα and the amount and function of mitochondria in skeletal muscle. Methods. Insulin resistance was induced by a high-fat (HF) diet for…

Cardiolipin content controls mitochondrial coupling and energetic efficiency in muscle

2020

Decreasing mitochondrial energy-production efficiency in skeletal muscle can confer protection against diet-induced obesity.