scholarly journals Reduced Levels of NAD in Skeletal Muscle and Increased Physiologic Frailty Are Associated With Viral Coinfection in Asymptomatic Middle-Aged Adults

2022 ◽  
Vol 89 (S1) ◽  
pp. S15-S22
Author(s):  
Thanh Tran ◽  
Karol M. Pencina ◽  
Michael B. Schultz ◽  
Zhuoying Li ◽  
Catherine Ghattas ◽  
...  
2010 ◽  
Vol 95 (9) ◽  
pp. E69-E74 ◽  
Author(s):  
Amy Fleischman ◽  
Hideo Makimura ◽  
Takara L. Stanley ◽  
Meaghan A. McCarthy ◽  
Matthew Kron ◽  
...  

2016 ◽  
Vol 120 (8) ◽  
pp. 965-975 ◽  
Author(s):  
Emily J. Arentson-Lantz ◽  
Kirk L. English ◽  
Douglas Paddon-Jones ◽  
Christopher S. Fry

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.


2020 ◽  
pp. 1-8
Author(s):  
Jing-An Long ◽  
Rong-Huan Zhong ◽  
Si Chen ◽  
Fan Wang ◽  
Yun Luo ◽  
...  

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.


2017 ◽  
Vol 66 (12) ◽  
pp. 1918-1927 ◽  
Author(s):  
Thanh Tran ◽  
Viola Guardigni ◽  
Karol M Pencina ◽  
Anthony A Amato ◽  
Michael Floyd ◽  
...  

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