Long-Term Habitual Exercise and Combination of β-hydroxy-β-methylbutyrate Plus Black Ginger Maintain Muscle Health in SAMP8 Mice

Muscle mass and strength decrease with aging, but habitual exercise can maintain muscle health. β-Hydroxy-β-methyl butyrate calcium (HMB) and black ginger (BG) are anti-oxidants that have been reported to improve muscle protein metabolism and energy production; these molecules may have synergistic effects. The senescence-accelerated mouse-prone 8 (SAMP8) model is a useful model of muscle aging. Therefore, in this study, we explored how the combination of habitual exercise, HMB, and BG affected muscle aging. We used 28-week-old SAMP8 mice divided into five groups: control, exercise (Ex), Ex+BG, Ex+HMB, and Ex+BG+HMB (Ex+Comb). Mice were required to run on a treadmill for 16 weeks at 5 days per week. In 44-week-old mice, grip strength tests and dissection were conducted. Muscle weight was measured, and the gastrocnemius muscle was subjected to quantitative polymerase chain reaction and immunoblotting. Muscle mass and strength were preserved in the Ex+Comb group, and mitochondrial function was preserved through suppressing oxidative stress. Muscle protein synthesis signaling was improved in the Ex+Comb group. Autophagy and the ubiquitin system were normalized by Ex+Comb treatment. Overall, habitual exercise and HMB plus BG treatment maintained muscle health by suppressing oxidative stress, preserving mitochondrial function, and maintaining muscle protein metabolism in SAMP8 mice.

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No difference in insulin sensitivity between healthy postmenopausal women with or without sarcopenia: a pilot study

Applied Physiology Nutrition and Metabolism ◽

10.1139/h07-005 ◽

2007 ◽

Vol 32 (3) ◽

pp. 426-433 ◽

Cited By ~ 13

Author(s):

Eric D.B. Goulet ◽

Christine Lord ◽

Jean-Philippe Chaput ◽

Mylène Aubertin-Leheudre ◽

Martin Brochu ◽

...

Keyword(s):

Insulin Sensitivity ◽

Total Energy ◽

Postmenopausal Women ◽

Muscle Mass ◽

Protein Metabolism ◽

Muscle Protein ◽

Fat Free Mass ◽

Older Individuals ◽

Food Record ◽

Muscle Protein Metabolism

Insulin plays a pivotal role in skeletal muscle protein metabolism and its action decreases with age. A loss of muscle mass, termed sarcopenia, also occurs with age. The age-associated decline in insulin sensitivity (IS) may negatively alter muscle protein metabolism and, therefore, be implicated in the aetiology of sarcopenia. However, no studies have yet compared the level of IS between older individuals with or without sarcopenia. Thus, in this study, we compared the IS of 20 class I sarcopenics (CIS), 8 class II sarcopeniscs (CIIS), and 16 non-sarcopenics (NS), among a group of otherwise healthy, non-obese, postmenopausal women. IS was estimated with the quantitative IS check index (QUICKI). Muscle mass index (MMI), which was used to determine sarcopenia, was calculated as follows: (appendicular muscle mass × 1.19) – 1.01/h2, where h = height. Fat-free mass (FFM), fat mass (FM), and trunk FM (TFM) were measured by dual-energy X-ray absorptiometry. Accelerometry and indirect calorimetry were used to estimate resting (REE), daily (DEE), and physical activity (PAEE) energy expenditure. A 3 d food record was used to determine total energy, protein (animal and vegetal), and carbohydrate intakes. As expected, MMI and FFM differed significantly among groups. However, no significant differences were found among groups for IS, FM, TFM, REE, DEE, PAEE, or total energy, protein (both animal and vegetable), and carbohydrate intakes. Using QUICKI, a surrogate measure of IS, the present results suggest that the action of insulin does not play an important role in the development and maintenance of sarcopenia in healthy, non-obese, postmenopausal women.

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Phenotypic regulation of animal skeletal muscle protein metabolism

Ukrainian Journal of Ecology ◽

10.15421/2019_804 ◽

2019 ◽

Vol 9 (4) ◽

pp. 651-656 ◽

Cited By ~ 2

Author(s):

K. T. Erimbetov ◽

O. V. Obvintseva ◽

A. V. Fedorova ◽

R. A. Zemlyanoy ◽

A. G. Solovieva

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Signaling Pathways ◽

Muscle Mass ◽

Protein Metabolism ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Mrna Translation ◽

Mtorc1 Signaling ◽

Muscle Protein Metabolism

This review highlights the current state of phenotypic mechanisms of regulation of muscle protein metabolism in animals. Since the skeletal muscle represents 40–50% of body mass in mammals it is a critical regulator of overall metabolism. Therefore, an understanding of the processes involved in the postnatal increase in muscle mass, with associated accumulation of protein, is fundamental. Throughout life, a delicate balance exists between protein synthesis and degradation that is essential for growth and normal health of humans and animals. Signaling pathways coordinate muscle protein balance. Anabolic and catabolic stimuli are integrated through the PKB/Akt-mTORC1 signaling to regulate mechanisms that control muscle protein synthesis and breakdown. At an early periods of intensive growth, muscle mass is stimulated by an increase in protein synthesis at the level of mRNA translation. Throughout the life, proteolytic processes including autophagy lysosomal system, ubiquitin proteasome pathway, calcium-dependent calpains and cysteine protease caspase enzyme cascade influence the growth of muscle mass. Several signal transmission networks direct and coordinate these processes along with quality control mechanisms to maintain protein homeostasis (proteostasis). Genetic factors, hormones, amino acids, phytoecdysteroids, and rhodanines affect the protein metabolism via signaling pathways, changing the ability and / or efficiency of muscle growth.

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