Search results for "Skeletal muscle"

Myostatin/activin blocking combined with exercise reconditions skeletal muscle expression profile of mdx mice

2015

Duchenne Muscular Dystrophy is characterized by muscle wasting and decreased aerobic metabolism. Exercise and blocking of myostatin/activin signaling may independently or combined counteract muscle wasting and dystrophies. The effects of myostatin/activin blocking using soluble activin receptor-Fc (sActRIIB-Fc) administration and wheel running were tested alone or in combination for seven weeks in dystrophic mdx mice. Expression microarray analysis revealed decreased aerobic metabolism in the gastrocnemius muscle of mdx mice compared to healthy mice. This was not due to reduced home-cage physical activity, and was further downregulated upon sActRIIB-Fc treatment in enlarged muscles. However…

Walking and Running Require Greater Effort from the Ankle than the Knee Extensor Muscles.

2016

The knee and ankle extensors as human primary antigravity muscle groups are of utmost importance in a wide range of locomotor activities. Yet, we know surprisingly little about how these muscle groups work, and specifically, how close to their maximal capacities they function across different modes and intensity of locomotion. Therefore, to advance our understanding of locomotor constraints, we determined and compared relative operating efforts of the knee and ankle extensors during walking, running, and sprinting.Using an inverse dynamics biomechanical analysis, the muscle forces of the knee and ankle extensors during walking (1.6 m·s), running (4.1 m·s), and sprinting (9.3 m·s) were quant…

Bioengineered in vitro 3D model of myotonic dystrophy type 1 human skeletal muscle

2021

Abstract Myotonic dystrophy type 1 (DM1) is the most common hereditary myopathy in the adult population. The disease is characterized by progressive skeletal muscle degeneration that produces severe disability. At present, there is still no effective treatment for DM1 patients, but the breakthroughs in understanding the molecular pathogenic mechanisms in DM1 have allowed the testing of new therapeutic strategies. Animal models and in vitro two-dimensional cell cultures have been essential for these advances. However, serious concerns exist regarding how faithfully these models reproduce the biological complexity of the disease. Biofabrication tools can be applied to engineer human three-dim…

Aberrant glycosylation of alpha-dystroglycan causes defective binding of laminin in the muscle of chicken muscular dystrophy.

2005

Dystroglycan is a central component of dystrophin-glycoprotein complex that links extracellular matrix and cytoskeleton in skeletal muscle. Although dystrophic chicken is well established as an animal model of human muscular dystrophy, the pathomechanism leading to muscular degeneration remains unknown. We show here that glycosylation and laminin-binding activity of alpha-dystroglycan (alpha-DG) are defective in dystrophic chicken. Extensive glycan structural analysis reveals that Galbeta1-3GalNAc and GalNAc residues are increased while Siaalpha2-3Gal structure is reduced in alpha-DG of dystrophic chicken. These results implicate aberrant glycosylation of alpha-DG in the pathogenesis of mus…

Duchenne Muscular Dystrophy (DMD): Should it be Considered a Systemic Disease?

2016

Duchenne muscular dystrophy (DMD) is an X-linked muscle disease characterized by progressive skeletal muscle loss and development of respiratory failure due to involvement of respiratory muscles. Similar to human DMD, the mdx mouse model lacks dystrophin but is characterized by relatively mild muscle injury, allowing testing the effects of mild endurance exercise training on dystrophic skeletal muscle. We were interested to study the effects of exercise training on airway cells in trained mdx mice by applying the same protocol previously tested in Swiss mice. We found that mdx mice showed little airway inflammation associated with training, but developed increasing apoptosis of airway cells…

Combined effect of AAV-U7-induced dystrophin exon skipping and soluble activin Type IIB receptor in mdx mice.

2012

Adeno-associated virus (AAV)-U7-mediated skipping of dystrophin-exon-23 restores dystrophin expression and muscle function in the mdx mouse model of Duchenne muscular dystrophy. Soluble activin receptor IIB (sActRIIB-Fc) inhibits signaling of myostatin and homologous molecules and increases muscle mass and function of wild-type and mdx mice. We hypothesized that combined treatment with AAV-U7 and sActRIIB-Fc may synergistically improve mdx muscle function. Bioactivity of sActRIIB-Fc on skeletal muscle was first demonstrated in wild-type mice. In mdx mice we show that AAV-U7-mediated dystrophin restoration improved specific muscle force and resistance to eccentric contractions when applied a…

Regulation of gene expression and steroidogenesis in skeletal muscle of postmenopausal women : with emphasis on the effects of hormone replacement an…

2011

DIFFERENTIAL INFLUENCE OF PERIPHERAL AND SYSTEMIC SEX STEROIDS ON SKELETAL MUSCLE QUALITY IN PRE- AND POSTMENOPAUSAL WOMEN.

2011

Aging is associated with gradual decline of skeletal muscle strength and mass often leading to diminished muscle quality. This phenomenon is known as sarcopenia and affects about 30% of the over 60-year-old population. Androgens act as anabolic agents regulating muscle mass and improving muscle performance. The role of female sex steroids as well as the ability of skeletal muscle tissue to locally produce sex steroids has been less extensively studied. We show that despite the extensive systemic deficit of sex steroid hormones in postmenopausal compared to premenopausal women, the hormone content of skeletal muscle does not follow the same trend. In contrast to the systemic levels, muscle t…

Decreasing muscle performance associated with increasing disease activity in patients with rheumatoid arthritis

2018

Objectives Increasing evidence suggests that inflammation has a detrimental effect on muscle strength. Our objective was to analyse the association between muscle performance and different disease activity levels in patients with rheumatoid arthritis (RA). Method A total of 199 consecutive outpatients were subject to cross-sectional assessment. Measurements of grip strength, endurance of the upper and lower limbs and trunk strength were combined as a muscle performance composite score (MPCS), using a standardised method. The disease activity for 28 joints (DAS28), radiographs of small joints (Larsen score), rheumatoid factor, body mass index (BMI), comorbidities and anti-rheumatic drugs wer…

Cold Exposure Affects Lipid Metabolism, Fatty Acids Composition and Transcription in Pig Skeletal Muscle

2021

Cold exposure promotes glucose oxidation and modulates the lipid metabolism in adipose tissue, but it is still not fully clear whether cold exposure could affect meat quality and fatty acid metabolism in skeletal muscle of pig in vivo. Here, we kept finishing pigs under cold or room temperature overnight and determined the effects of cold exposure on meat quality, fatty acids composition and transcriptional changes in skeletal muscle of pigs. We found that cold exposure significantly reduced the meat colour24 h and pH24 h, without affecting carcass characteristics and other meat quality traits. Considerable changes were found in the proportions of individual fatty acids and the total conten…