Grosicki G J, Barrett B B, Englund D A, Liu C, Travison T G, Cederholm T, Koochek A, von Berens Å, Gustafsson T, Benard T, Reid K F, Fielding R A
Gregory J. Grosicki, Ph.D., Department of Health Sciences and Kinesiology, Biodynamics and Human Performance Center, Georgia Southern University (Armstrong Campus), 11935 Abercorn Street, Savannah, GA, 31419. Phone: (912) 344-3317. Fax: (912) 344-3490. Email:
J Frailty Aging. 2020;9(1):57-63. doi: 10.14283/jfa.2019.30.
Human aging is characterized by a chronic, low-grade inflammation suspected to contribute to reductions in skeletal muscle size, strength, and function. Inflammatory cytokines, such as interleukin-6 (IL-6), may play a role in the reduced skeletal muscle adaptive response seen in older individuals.
To investigate relationships between circulating IL-6, skeletal muscle health and exercise adaptation in mobility-limited older adults.
Randomized controlled trial.
Exercise laboratory on the Health Sciences campus of an urban university.
99 mobility-limited (Short Physical Performance Battery (SPPB) ≤9) older adults.
6-month structured physical activity with or without a protein and vitamin D nutritional supplement.
Circulating IL-6, skeletal muscle size, composition (percent normal density muscle tissue), strength, power, and specific force (strength/CSA) as well as physical function (gait speed, stair climb time, SPPB-score) were measured pre- and post-intervention.
At baseline, Spearman's correlations demonstrated an inverse relationship (P<0.05) between circulating IL-6 and thigh muscle composition (r = -0.201), strength (r = -0.311), power (r = -0.210), and specific force (r = -0.248), and positive association between IL-6 and stair climb time (r = 0.256; P<0.05). Although the training program did not affect circulating IL-6 levels (P=0.69), reductions in IL-6 were associated with gait speed improvements (r = -0.487; P<0.05) in "higher" IL-6 individuals (>1.36 pg/ml). Moreover, baseline IL-6 was inversely associated (P<0.05) with gains in appendicular lean mass and improvements in SPPB score (r = -0.211 and -0.237, respectively).
These findings implicate age-related increases in circulating IL-6 as an important contributor to declines in skeletal muscle strength, quality, function, and training-mediated adaptation. Given the pervasive nature of inflammation among older adults, novel therapeutic strategies to reduce IL-6 as a means of preserving skeletal muscle health are enticing.
人类衰老的特征是慢性低度炎症，这种炎症被认为会导致骨骼肌大小、力量和功能下降。炎性细胞因子，如白细胞介素-6（IL-6），可能在老年人骨骼肌适应性反应降低中起作用。
研究行动受限的老年人循环IL-6、骨骼肌健康与运动适应性之间的关系。
随机对照试验。
一所城市大学健康科学园区的运动实验室。
99名行动受限（简短身体机能测试量表（SPPB）≤9）的老年人。
进行为期6个月的结构化体育活动，同时服用或不服用蛋白质和维生素D营养补充剂。
在干预前后测量循环IL-6、骨骼肌大小、组成（正常密度肌肉组织百分比）、力量、功率和比肌力（力量/横截面积）以及身体功能（步速、爬楼梯时间、SPPB评分）。
在基线时，Spearman相关性分析显示，循环IL-6与大腿肌肉组成（r = -0.201）、力量（r = -0.311）、功率（r = -0.210）和比肌力（r = -0.248）呈负相关（P<0.05），与爬楼梯时间呈正相关（r = 0.256；P<0.05）。尽管训练计划未影响循环IL-6水平（P = 0.69），但在“较高”IL-6水平（>1.36 pg/ml）的个体中，IL-6的降低与步速改善相关（r = -0.487；P<0.05）。此外，基线IL-6与四肢瘦体重增加和SPPB评分改善呈负相关（P<0.05）（分别为r = -0.211和-0.237）。
这些发现表明，循环IL-6随年龄增长而增加是骨骼肌力量、质量、功能下降以及训练介导的适应性下降的重要原因。鉴于炎症在老年人中普遍存在，作为一种保护骨骼肌健康的手段，降低IL-6的新型治疗策略很有吸引力。
