Exercise Physiology Research Group, Department of Movement Sciences, KU Leuven, Belgium.
Physical Activity, Sports and Health Research Group, Department of Movement Sciences, KU Leuven, Belgium.
J Gerontol A Biol Sci Med Sci. 2021 Feb 25;76(3):406-414. doi: 10.1093/gerona/glaa309.
Old skeletal muscle exhibits decreased anabolic sensitivity, eventually contributing to muscle wasting. Besides anabolism, also muscle inflammation and catabolism are critical players in regulating the old skeletal muscle's sensitivity. Omega-3 fatty acids (ω-3) are an interesting candidate to reverse anabolic insensitivity via anabolic actions. Yet, it remains unknown whether ω-3 also attenuates muscle inflammation and catabolism. The present study investigates the effect of ω-3 supplementation on muscle inflammation and metabolism (anabolism/catabolism) upon resistance exercise (RE). Twenty-three older adults (65-84 years; 8♀) were randomized to receive ω-3 (~3 g/d) or corn oil (placebo [PLAC]) and engaged in a 12-week RE program (3×/wk). Before and after intervention, muscle volume, strength, and systemic inflammation were assessed, and muscle biopsies were analyzed for markers of anabolism, catabolism, and inflammation. Isometric knee-extensor strength increased in ω-3 (+12.2%), but not in PLAC (-1.4%; pinteraction = .015), whereas leg press strength improved in both conditions (+27.1%; ptime < .001). RE, but not ω-3, decreased inflammatory (p65NF-κB) and catabolic (FOXO1, LC3b) markers, and improved muscle quality. Yet, muscle volume remained unaffected by RE and ω-3. Accordingly, muscle anabolism (mTORC1) and plasma C-reactive protein remained unchanged by RE and ω-3, whereas serum IL-6 tended to decrease in ω-3 (pinteraction = .07). These results show that, despite no changes in muscle volume, RE-induced gains in isometric strength can be further enhanced by ω-3. However, ω-3 did not improve RE-induced beneficial catabolic or inflammatory adaptations. Irrespective of muscle volume, gains in strength (primary criterion for sarcopenia) might be explained by changes in muscle quality due to muscle inflammatory or catabolic signaling.
衰老骨骼肌表现出合成代谢敏感性降低，最终导致肌肉减少。除了合成代谢外，肌肉炎症和分解代谢也是调节衰老骨骼肌敏感性的关键因素。ω-3 脂肪酸（ω-3）是通过合成代谢作用逆转合成代谢不敏感的一个有趣候选物。然而，ω-3 是否也能减轻肌肉炎症和分解代谢仍不清楚。本研究旨在探讨 ω-3 补充对抵抗运动（RE）后肌肉炎症和代谢（合成代谢/分解代谢）的影响。23 名老年人（65-84 岁；8 名女性）被随机分为 ω-3（~3 g/d）或玉米油（安慰剂 [PLAC]）组，并进行 12 周的 RE 计划（每周 3 次）。干预前后评估肌肉体积、力量和全身炎症，并分析肌肉活检以评估合成代谢、分解代谢和炎症标志物。等长膝关节伸展力量在 ω-3 组增加（+12.2%），而在 PLAC 组没有增加（-1.4%；p 交互 =.015），而腿部按压力量在两种情况下均增加（+27.1%；p 时间<.001）。RE 而不是 ω-3 降低了炎症（p65NF-κB）和分解代谢（FOXO1、LC3b）标志物，并改善了肌肉质量。然而，RE 和 ω-3 对肌肉体积均无影响。因此，RE 和 ω-3 对肌肉合成代谢（mTORC1）和血浆 C 反应蛋白没有影响，而血清 IL-6 在 ω-3 组有下降趋势（p 交互 =.07）。这些结果表明，尽管肌肉体积没有变化，但 ω-3 可以进一步增强 RE 引起的等长力量增加。然而，ω-3 并没有改善 RE 引起的有益的分解代谢或炎症适应。无论肌肉体积如何，力量的增加（肌少症的主要标准）可能是由于肌肉炎症或分解代谢信号导致的肌肉质量变化所解释的。
