scholarly journals Fourteen days of bed rest induces a decline in satellite cell content and robust atrophy of skeletal muscle fibers in middle-aged adults

2016 ◽  
Vol 120 (8) ◽  
pp. 965-975 ◽  
Author(s):  
Emily J. Arentson-Lantz ◽  
Kirk L. English ◽  
Douglas Paddon-Jones ◽  
Christopher S. Fry
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cell ◽  
Bed Rest ◽  
Capillary Density ◽  
Peak Oxygen Consumption ◽  
Fiber Types ◽  
Middle Aged ◽  
Cell Content ◽  
Middle Aged Adults ◽  
Change In Mean

Bed rest, a ground-based spaceflight analog, induces robust atrophy of skeletal muscle, an effect that is exacerbated with increasing age. We examined the effect of 14 days of bed rest on skeletal muscle satellite cell content and fiber type atrophy in middle-aged adults, an understudied age demographic with few overt signs of muscle aging that is representative of astronauts who perform long-duration spaceflight. Muscle biopsies were obtained from the vastus lateralis of healthy middle-aged adults [ n = 7 (4 male, 3 female); age: 51 ± 1 yr] before (Pre-BR) and after (Post-BR) 14 days of bed rest. Immunohistochemical analyses were used to quantify myosin heavy chain (MyHC) isoform expression, cross-sectional area (CSA), satellite cell and myonuclear content, and capillary density. Peak oxygen consumption, knee extensor strength, and body composition were also measured Pre-BR and Post-BR. Post-BR MyHC type 2a fiber percentage was reduced, and mean CSA decreased in all fiber types (−24 ± 5%; P < 0.05). Satellite cell content was also reduced Post-BR (−39 ± 9%; P < 0.05), and the change in satellite cell content was significantly correlated with the change in mean fiber CSA ( r2 = 0.60; P < 0.05). A decline in capillary density was observed Post-BR (−23 ± 6%; P < 0.05), and Post-BR capillary content was significantly associated with Post-BR peak aerobic capacity ( r2 = 0.59; P < 0.05). A subtle decline in myonuclear content occurred during bed rest (−5 ± 1%; P < 0.05). The rapid maladaptation of skeletal muscle to 14 days of mechanical unloading in middle-aged adults emphasizes the need for robust countermeasures to preserve muscle function in astronauts.

scholarly journals Skeletal Muscle Phosphocreatine Recovery after Submaximal Exercise in Children and Young and Middle-Aged Adults

2010 ◽  
Vol 95 (9) ◽  
pp. E69-E74 ◽  
Author(s):  
Amy Fleischman ◽  
Hideo Makimura ◽  
Takara L. Stanley ◽  
Meaghan A. McCarthy ◽  
Matthew Kron ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Submaximal Exercise ◽  
Middle Aged ◽  
Middle Aged Adults

scholarly journals A sex-specific relationship between capillary density and anaerobic threshold

2009 ◽  
Vol 106 (4) ◽  
pp. 1181-1186 ◽  
Author(s):  
Jennifer L. Robbins ◽  
Brian D. Duscha ◽  
Daniel R. Bensimhon ◽  
Karlman Wasserman ◽  
James E. Hansen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Anaerobic Threshold ◽  
Control Period ◽  
Exercise Program ◽  
Capillary Density ◽  
Peak Oxygen Consumption ◽  
Oxidative Potential ◽  
Specific Effects ◽  
Two Measures

Although both capillary density and peak oxygen consumption (V̇o2) improve with exercise training, it is difficult to find a relationship between these two measures. It has been suggested that peak V̇o2 may be more related to central hemodynamics than to the oxidative potential of skeletal muscle, which may account for this observation. We hypothesized that change in a measure of submaximal performance, anaerobic threshold, might be related to change in skeletal muscle capillary density, a marker of oxidative potential in muscle, with training. Due to baseline differences among these variables, we also hypothesized that relationships might be sex specific. A group of 21 subjects completed an inactive control period, whereas 28 subjects (17 men and 11 women) participated in a 6-mo high-intensity exercise program. All subjects were sedentary, overweight, and dyslipidemic. Potential relationships were assessed between change in capillary density with both change in V̇o2 at peak and at anaerobic threshold with exercise training. All variables and relationships were assessed for sex-specific effects. Change in peak V̇o2 was not related to change in capillary density after exercise training in either sex. Men had a positive correlation between change in V̇o2 at anaerobic threshold and change in capillary density with exercise training ( r = 0.635; P < 0.01), whereas women had an inverse relationship ( r = −0.636; P < 0.05) between the change in these variables. These findings suggest that, although enhanced capillary density is associated with training-induced improvements in submaximal performance in men, this relationship is different in women.

Dietary betaine intake is associated with skeletal muscle mass change over 3 years in middle-aged adults: the Guangzhou Nutrition and Health Study

2020 ◽  
pp. 1-8
Author(s):  
Jing-An Long ◽  
Rong-Huan Zhong ◽  
Si Chen ◽  
Fan Wang ◽  
Yun Luo ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Health Study ◽  
Middle Aged ◽  
Nutrition And Health ◽  
Skeletal Mass ◽  
Age Related ◽  
Middle Aged Adults

Abstract A higher dietary intake or serum concentration of betaine has been associated with greater lean body mass in middle-aged and older adults. However, it remains unknown whether betaine intake is associated with age-related loss of skeletal muscle mass (SMM). We assessed the association between dietary betaine intake and relative changes in SMM after 3 years in middle-aged adults. A total of 1242 participants aged 41–60 years from the Guangzhou Nutrition and Health Study 2011–2013 and 2014–2017 with body composition measurements by dual-energy X-ray absorptiometry were included. A face-to-face questionnaire was used to collect general baseline information. After adjustment for potential confounders, multiple linear regression found that energy-adjusted dietary betaine intake was significantly and positively associated with relative changes (i.e. percentage loss or increase) in SMM of legs, limbs and appendicular skeletal mass index (ASMI) over 3 years of follow-up (β 0·322 (se 0·157), 0·309 (se 0·142) and 0·303 (se 0·145), respectively; P < 0·05). The ANCOVA models revealed that participants in the highest betaine tertile had significantly less loss in SMM of limbs and ASMI and more increase in SMM of legs over 3 years of follow-up, compared with those in the bottom betaine tertile (all Ptrend < 0·05). In conclusion, our findings suggest that elevated higher dietary betaine intake may be associated with less loss of SMM of legs, limbs and ASMI in middle-aged adults.

scholarly journals Relations of Arterial Stiffness With Postural Change in Mean Arterial Pressure in Middle-Aged Adults

Hypertension ◽  
2017 ◽  
Vol 69 (4) ◽  
pp. 685-690 ◽  
Author(s):  
Alyssa Torjesen ◽  
Leroy L. Cooper ◽  
Jian Rong ◽  
Martin G. Larson ◽  
Naomi M. Hamburg ◽  
...  
Keyword(s):  
Mean Arterial Pressure ◽  
Arterial Stiffness ◽  
Arterial Pressure ◽  
Postural Change ◽  
Middle Aged ◽  
Middle Aged Adults ◽  
Change In Mean

The effect of rowing ergometry and resistive exercise on skeletal muscle structure and function during bed rest

2014 ◽  
Vol 116 (12) ◽  
pp. 1569-1581 ◽  
Author(s):  
Felix Krainski ◽  
Jeffrey L. Hastings ◽  
Katja Heinicke ◽  
Nadine Romain ◽  
Eric L. Pacini ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Strength Training ◽  
Short Duration ◽  
High Intensity ◽  
Bed Rest ◽  
Muscle Volume ◽  
Muscle Fiber Types ◽  
Resonance Spectroscopy ◽  
Fiber Types ◽  
Rowing Ergometry

Exposure to microgravity causes functional and structural impairment of skeletal muscle. Current exercise regimens are time-consuming and insufficiently effective; an integrated countermeasure is needed that addresses musculoskeletal along with cardiovascular health. High-intensity, short-duration rowing ergometry and supplemental resistive strength exercise may achieve these goals. Twenty-seven healthy volunteers completed 5 wk of head-down-tilt bed rest (HDBR): 18 were randomized to exercise, 9 remained sedentary. Exercise consisted of rowing ergometry 6 days/wk, including interval training, and supplemental strength training 2 days/wk. Measurements before and after HDBR and following reambulation included assessment of strength, skeletal muscle volume (MRI), and muscle metabolism (magnetic resonance spectroscopy); quadriceps muscle biopsies were obtained to assess muscle fiber types, capillarization, and oxidative capacity. Sedentary bed rest (BR) led to decreased muscle volume (quadriceps: −9 ± 4%, P < 0.001; plantar flexors: −19 ± 6%, P < 0.001). Exercise (ExBR) reduced atrophy in the quadriceps (−5 ± 4%, interaction P = 0.018) and calf muscle, although to a lesser degree (−14 ± 6%, interaction P = 0.076). Knee extensor and plantar flexor strength was impaired by BR (−14 ± 15%, P = 0.014 and −22 ± 7%, P = 0.001) but preserved by ExBR (−4 ± 13%, P = 0.238 and +13 ± 28%, P = 0.011). Metabolic capacity, as assessed by maximal O2 consumption, 31P-MRS, and oxidative chain enzyme activity, was impaired in BR but stable or improved in ExBR. Reambulation reversed the negative impact of BR. High-intensity, short-duration rowing and supplemental strength training effectively preserved skeletal muscle function and structure while partially preventing atrophy in key antigravity muscles. Due to its integrated cardiovascular benefits, rowing ergometry could be a primary component of exercise prescriptions for astronauts or patients suffering from severe deconditioning.

Increased capillary density in skeletal muscle is not associated with impaired insulin sensitivity induced by bed rest in healthy young men

2018 ◽  
Vol 43 (12) ◽  
pp. 1334-1340 ◽  
Author(s):  
David Montero ◽  
Laura Oberholzer ◽  
Thomas Haider ◽  
Andreas Breenfeldt-Andersen ◽  
Sune Dandanell ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Glucose Homeostasis ◽  
Physical Inactivity ◽  
Bed Rest ◽  
Capillary Density ◽  
Human Model ◽  
Full Time ◽  
Matsuda Index

Physical inactivity alters glucose homeostasis in skeletal muscle, potentially developing into overt metabolic disease. The present study sought to investigate the role of skeletal muscle capillarization in glucose tolerance and insulin sensitivity (IS) using a classic human model of physical inactivity. Thirteen healthy males (age = 23 ± 2 years) underwent 4 days of full-time supervised and diet-controlled bed rest. Oral glucose tolerance test, indices of IS (quantitative insulin sensitivity check index (QUICKI), Matsuda index), as well as skeletal muscle biopsies with measurement of fiber type distribution, fiber cross-sectional area (FCSA), capillary-to-fiber ratio (C/F ratio), and capillary density (CD) were assessed prior to and after bed rest. Body weight and composition were unaltered by bed rest. Fasting glucose/insulin ratio (G0/I0 ratio) (−25%, P = 0.016), QUICKI (−7%, P = 0.023), and Matsuda index (−24%, P = 0.003) diminished with bed rest. Skeletal muscle FCSA decreased (−737.4 ± 763.2 μm−2 (−12%), P = 0.005) while C/F ratio was preserved, resulting in augmented CD (+93.9 ± 91.5 capillaries·mm−2 (+37%), P = 0.003) with bed rest. No association was detected between changes in skeletal muscle variables and metabolic outcomes. Independently of bed rest-induced effects, a positive linear relationship was detected between C/F ratio and G0/I0 ratio (β = 17.09, P = 0.021). In conclusion, impaired glucose homeostasis with bed rest is not prevented nor associated with enhanced skeletal muscle capillarization in healthy individuals.

Effect of Maternal Dietary Fat on Skeletal Muscle Cellularity and Satellite Cell Content of the Porcine Fetus at 110 Days of Gestation

1984 ◽  
Vol 120 (3) ◽  
pp. 170-172
Author(s):  
Dennis R. Campion ◽  
Robert W. Seerley ◽  
Cindy L. Kveragas
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cell ◽  
Dietary Fat ◽  
Cell Content
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