scholarly journals Intense interval training in healthy older adults increases skeletal muscle [3 H]ouabain-binding site content and elevates Na+ ,K+ -ATPase α2 isoform abundance in Type II fibers

2017 ◽  
Vol 5 (7) ◽  
pp. e13219 ◽  
Author(s):  
Victoria L. Wyckelsma ◽  
Itamar Levinger ◽  
Robyn M. Murphy ◽  
Aaron C. Petersen ◽  
Ben D. Perry ◽  
...  
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Binding Site ◽  
Interval Training ◽  
Type Ii ◽  
Ouabain Binding ◽  
Healthy Older Adults ◽  
Type Ii Fibers

scholarly journals Resistance exercise training promotes fiber type-specific myonuclear adaptations in older adults

2020 ◽  
Vol 128 (4) ◽  
pp. 795-804 ◽  
Author(s):  
Tatiana Moro ◽  
Camille R. Brightwell ◽  
Elena Volpi ◽  
Blake B. Rasmussen ◽  
Christopher S. Fry
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Exercise Training ◽  
Fiber Type ◽  
Type I ◽  
Type Ii ◽  
Resistance Exercise Training ◽  
Myonuclear Domain ◽  
Type I Fibers ◽  
Type Ii Fibers

Aging induces physiological decline in human skeletal muscle function and morphology, including type II fiber atrophy and an increase in type I fiber frequency. Resistance exercise training (RET) is an effective strategy to overcome muscle mass loss and improve strength, with a stronger effect on type II fibers. In the present study, we sought to determine the effect of a 12-wk progressive RET program on the fiber type-specific skeletal muscle hypertrophic response in older adults. Nineteen subjects [10 men and 9 women (71.1 ± 4.3 yr)] were studied before and after the 12-wk program. Immunohistochemical analysis was used to quantify myosin heavy chain (MyHC) isoform expression, cross-sectional area (CSA), satellite cell abundance, myonuclear content, and lipid droplet density. RET induced an increase in MyHC type II fiber frequency and a concomitant decrease in MyHC type I fiber frequency. Mean CSA increased significantly only in MyHC type II fibers (+23.3%, P < 0.05), but myonuclear content increased only in MyHC type I fibers ( P < 0.05), with no change in MyHC type II fibers. Satellite cell content increased ~40% in both fiber types ( P > 0.05). RET induced adaptations to the capillary supply to satellite cells, with the distance between satellite cells and the nearest capillary increasing in type I fibers and decreasing in type II fibers. Both fiber types showed similar decrements in intramuscular lipid density with training ( P < 0.05). Our data provide intriguing evidence for a fiber type-specific response to RET in older adults and suggest flexibility in the myonuclear domain of type II fibers during a hypertrophic stimulus. NEW & NOTEWORTHY In older adults, progressive resistance exercise training (RET) increased skeletal muscle fiber volume and cross-sectional area independently of myonuclear accretion, leading to an expansion of the myonuclear domain. Fiber type-specific analyses illuminated differential adaptation; type II fibers underwent hypertrophy and exhibited myonuclear domain plasticity, whereas myonuclear accretion occurred in type I fibers in the absence of a robust hypertrophic response. RET also augmented satellite cell-capillary interaction and reduced intramyocellular lipid density to improve muscle quality.

Muscle Biopsy Samples for Histochemical Processing: Alterations Induced by Storage

1988 ◽  
Vol 25 (1) ◽  
pp. 77-82 ◽  
Author(s):  
K. G. Braund ◽  
K. A. Amling
Keyword(s):  
Skeletal Muscle ◽  
Cell Morphology ◽  
Type I ◽  
Type Ii ◽  
Tissue Samples ◽  
Frozen Tissue ◽  
Fresh Frozen ◽  
Healthy Dogs ◽  
Morphology And Morphometry ◽  
Type Ii Fibers

Skeletal muscle samples from two healthy dogs were stored in ice at 0 C for up to 30 hours to examine the influence of time on cell morphology and morphometry. Cytochemical and histochemical properties of muscle to 18 hours were not markedly different from fresh frozen tissue. Samples stored to 30 hours were still satisfactory, despite a decline and unevenness in depth of staining. Morphometry from samples stored at 0 C for 6 hours or longer is not recommended, due to the statistically significant increase in diameter (from 21 to 25%) of type I and type II fibers.

Sprint training increases human skeletal muscle Na(+)-K(+)-ATPase concentration and improves K+ regulation

1993 ◽  
Vol 75 (1) ◽  
pp. 173-180 ◽  
Author(s):  
M. J. McKenna ◽  
T. A. Schmidt ◽  
M. Hargreaves ◽  
L. Cameron ◽  
S. L. Skinner ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Binding Site ◽  
Intermittent Exercise ◽  
Recovery Period ◽  
Muscle Performance ◽  
Vastus Lateralis Muscle ◽  
Work Output ◽  
Sprint Training ◽  
Ouabain Binding ◽  
Before And After

This study investigated the effects of sprint training on muscle Na(+)-K(+)-adenosinetriphosphatase (ATPase) concentration, plasma [K+] regulation, muscle performance, and fatigue during severe intermittent exercise. Six untrained male subjects underwent intensive cycle-sprint training for 7 wk. Muscle biopsies were taken at rest from the vastus lateralis muscle before and after 7 wk of training and were assayed for Na(+)-K(+)-ATPase concentration using vanadate-facilitated [3H]ouabain binding to intact samples. Before and after the training period, subjects performed four maximal 30-s exercise bouts (EB) on a cycle ergometer, each separated by a 4-min recovery. Arterialized venous blood samples were drawn immediately before and after each sprint bout and were analyzed for plasma [K+]. The work output was significantly elevated (11%) across all four EBs after training. The muscle [3H]ouabain binding site concentration was significantly increased (16%) from 333 +/- 19 to 387 +/- 15 (SE) pmol/g wet wt after training but was unchanged in muscle obtained from three control subjects. Plasma [K+] rose by 1–2 mmol/l with each EB and declined rapidly by the end of each recovery period. The increases in plasma [K+] resulting from each EB were significantly lower (19%) after training. The ratios of rise in plasma [K+] relative to work output during each EB were also significantly lower (27%) after training. The increased muscle [3H]ouabain binding site concentration and the reduced ratio of rise in [K+] relative to work output with exercise are both consistent with improved plasma and skeletal muscle K+ regulation after sprint training.

Antioxidant pathways in human aged skeletal muscle: relationship with the distribution of type II fibers

2002 ◽  
Vol 37 (8-9) ◽  
pp. 1069-1075 ◽  
Author(s):  
Orietta Pansarasa ◽  
Giorgio Felzani ◽  
Jacopo Vecchiet ◽  
Fulvio Marzatico
Keyword(s):  
Skeletal Muscle ◽  
Type Ii ◽  
Type Ii Fibers

Effect of 10 Days of Bed Rest on Skeletal Muscle in Healthy Older Adults

JAMA ◽  
2007 ◽  
Vol 297 (16) ◽  
pp. 1769 ◽  
Author(s):  
Patrick Kortebein ◽  
Arny Ferrando ◽  
Juan Lombeida ◽  
Robert Wolfe ◽  
William J. Evans
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Bed Rest ◽  
Healthy Older Adults

Hypothyroid Myopathy in Two Dogs

1981 ◽  
Vol 18 (5) ◽  
pp. 589-598 ◽  
Author(s):  
K. G. Braund ◽  
A. R. Dillon ◽  
J. R. August ◽  
V. K. Ganjam
Keyword(s):  
Skeletal Muscle ◽  
Neuromuscular Disease ◽  
Matched Control ◽  
Primary Hypothyroidism ◽  
Type Ii ◽  
Biopsy Specimens ◽  
Fiber Size ◽  
Pronounced Reduction ◽  
Type Ii Fibers ◽  
Hypothyroid Myopathy

Biopsy specimens of skeletal muscle and peripheral nerve from two dogs with primary hypothyroidism but without clinical neuromuscular disease were studied with histological, histochemical and morphometric techniques. The most prominent change in skeletal muscle was variation in fiber size associated with a pronounced reduction in mean diameter of type II fibers. Type II fiber loss was apparent in the specimen from one dog. No histological or morphometric differences were noted in nerves from either dog compared with an age-matched control. The myopathic findings suggest a preferential metabolic defect in type II muscle fibers.

scholarly journals Short-term bed rest increases TLR4 and IL-6 expression in skeletal muscle of older adults

2013 ◽  
Vol 305 (3) ◽  
pp. R216-R223 ◽  
Author(s):  
Micah J. Drummond ◽  
Kyle L. Timmerman ◽  
Melissa M. Markofski ◽  
Dillon K. Walker ◽  
Jared M. Dickinson ◽  
...  
Keyword(s):  
Older Adults ◽  
Skeletal Muscle ◽  
Inflammatory Cytokines ◽  
Muscle Biopsy ◽  
Lean Mass ◽  
Bed Rest ◽  
Short Term ◽  
Tlr4 Signaling ◽  
Adult Skeletal Muscle ◽  
Healthy Older Adults

Bed rest induces significant loss of leg lean mass in older adults. Systemic and tissue inflammation also accelerates skeletal muscle loss, but it is unknown whether inflammation is associated to inactivity-induced muscle atrophy in healthy older adults. We determined if short-term bed rest increases toll-like receptor 4 (TLR4) signaling and pro-inflammatory markers in older adult skeletal muscle biopsy samples. Six healthy, older adults underwent seven consecutive days of bed rest. Muscle biopsies (vastus lateralis) were taken after an overnight fast before and at the end of bed rest. Serum cytokine expression was measured before and during bed rest. TLR4 signaling and cytokine mRNAs associated with pro- and anti-inflammation and anabolism were measured in muscle biopsy samples using Western blot analysis and qPCR. Participants lost ∼4% leg lean mass with bed rest. We found that after bed rest, muscle levels of TLR4 protein expression and interleukin-6 (IL-6), nuclear factor-κB1, interleukin-10, and 15 mRNA expression were increased after bed rest ( P < 0.05). Additionally, the cytokines interferon-γ, and macrophage inflammatory protein-1β, were elevated in serum samples following bed rest ( P < 0.05). We conclude that short-term bed rest in older adults modestly increased some pro- and anti-inflammatory cytokines in muscle samples while systemic changes in pro-inflammatory cytokines were mostly absent. Upregulation of TLR4 protein content suggests that bed rest in older adults increases the capacity to mount an exaggerated, and perhaps unnecessary, inflammatory response in the presence of specific TLR4 ligands, e.g., during acute illness.

scholarly journals Histochemical and Morphometric Evaluation of Skeletal Muscle from Horses with Exertional Rhabdomyolysis (Tying-up)

1986 ◽  
Vol 23 (4) ◽  
pp. 400-410 ◽  
Author(s):  
S. A. McEwen ◽  
T. J. Hulland
Keyword(s):  
Skeletal Muscle ◽  
Clinical Signs ◽  
Gluteus Medius ◽  
Control Group ◽  
Type Ii ◽  
Cross Sectional ◽  
Gluteus Medius Muscle ◽  
Exertional Rhabdomyolysis ◽  
Exercise Period ◽  
Type Ii Fibers

Thirteen horses with histories of exertional rhabdomyolysis were exercised for 20 minutes to induce clinical signs of lameness, elevated serum creatine kinase (CK), and aspartate aminotransferase (AST) activities and skeletal muscle morphologic lesions. The clinical signs exhibited by affected horses included trembling, sweating, increased rate of respiration, and restricted limb movement. Serum CK reached maximal activity between 4 and 8 hours after the exercise period and serum AST activity peaked between 24 and 48 hours. Histologically, the skeletal muscle lesions in muscle biopsies 24 hours after the exercise period consisted of segmental muscle fiber degeneration. Damaged muscle fibers were repaired by myoblastic regeneration. Horses with moderate (>1,500 U/liter) to severe (>5,000 U/liter) elevations of serum CK activity accompanied by clinical signs of muscle soreness induced by exercise, had visible muscle fiber degeneration microscopically. Frozen sections of biopsies of the gluteus medius muscle from affected ( n = 13) and control ( n = 11) groups of horses were processed to demonstrate myofibrillar ATPase activity. These sections were then used to determine fiber types, area percentages, and mean cross sectional fiber sizes. The mean type I, type II, and intermediate fiber sizes were significantly larger in the affected group than in the control group. In the gluteus medius muscles of the affected group, there was a significantly greater percentage of intermediate fibers and a significantly greater percentage of area occupied by intermediate fibers than in the control group. In the muscle samples with acute lesions of exertional rhabdomyolysis, type II fibers were selectively but not exclusively affected. In one horse which was subsequently necropsied 24 hours after the exercise period, lesions were present in several postural muscles, the masseter muscle and the heart. We conclude that the gluteus medius muscle fibers of affected horses are larger in cross sectional area than those of control horses and that there is preferential degeneration of type II fibers in acute lesions of exertional rhabdomyolysis.

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