Microgravity-induced skeletal muscle atrophy in women and men: implications for long-duration spaceflights to the Moon and Mars.

The inclusion of women on spaceflights has historically been limited. Recently, the first woman who will travel to the Moon was selected, and more women are participating in long-duration spaceflights. However, physiological data from real and simulated microgravity exposure are limited in women.

Skeletal muscle morphology, satellite cells, and oxidative profile in relation to physical function and lifelong endurance training in very old men.

In the current study, we compared muscle morphology in three advanced aging cohorts that differed in physical function, including a unique cohort of lifelong endurance athletes. Biopsies from the vastus lateralis muscle of seven lifelong endurance athletes (EAs) aged 82-92 yr, and 19 subjects from the Uppsala Longitudinal Study of Adult Men (ULSAM) aged 87-91 yr were analyzed. ULSAM subjects were divided into high- ( = 9, HF) and low- ( = 10, LF) function groups based on strength and physical function tests.

Early accentuated muscle hypertrophy is strongly associated with myonuclear accretion.

The current study explored whether the marked hypertrophic response noted with a short-term unilateral concurrent exercise paradigm was associated with more prominent changes in myonuclei accretion, ribosome biogenesis, and capillarization compared with resistance exercise alone (RE). Ten men (age 25 ± 4 yr) performed aerobic and resistance exercise (AE + RE) for one leg while the other leg did RE. Muscle biopsies were obtained before and after 5 wk of training and subjected to fiber-type specific immunohistochemical analysis, and quantification of total RNA content and mRNA/rRNA transcript abundance.

Three months of bed rest induce a residual transcriptomic signature resilient to resistance exercise countermeasures.

This study explored the muscle genome-wide response to long-term unloading (84-day bed rest) in 21 men. We hypothesized that a part of the bed rest-induced gene expression signature would be resilient to a concurrent flywheel resistance exercise (RE) countermeasure. Using DNA microarray technology analyzing 35 345 gene-level probe-sets, we identified 335 annotated probe-sets that were downregulated, and 315 that were upregulated after bed rest (P < .