Planella-Farrugia Cristina, Comas Ferran, Sabater-Masdeu Mònica, Moreno María, Moreno-Navarrete José María, Rovira Oscar, Ricart Wifredo, Fernández-Real José Manuel
Department of Diabetes, Endocrinology and Nutrition, Girona Biomedical Research Institute (IdIBGi), CIBEROBN (CB06/03/010) and Carlos III Health Institute (ISCIII), Girona, Spain.
Department of Medicine, University of Girona, Girona, Spain.
Front Physiol. 2019 Jul 10;10:871. doi: 10.3389/fphys.2019.00871. eCollection 2019.
Aging is a physiological process known to produce changes in body composition, affecting the musculature and leading to decreased muscle strength. Muscle in response to exercise acts as an endocrine organ, producing and releasing myokines such as irisin and myostatin that modulate muscular growth. Here, we aimed to evaluate the effects of low intensity resistance exercise, with or without protein supplementation, on body composition, anthropometric parameters and circulating irisin and myostatin in elderly subjects.
This is a prospective and controlled clinical trial in which subjects were randomized into 3 groups: (1) control group ( = 20), (2) low intensity resistance exercise group (RE) ( = 14), and (3) low intensity resistance exercise and nutritional support group (RENS) ( = 9). Participants, aged 60-75 years, were studied at baseline and 16 weeks thereafter. Body composition was evaluated through bioelectric impedance. Serum irisin and myostatin was measured using ELISA.
At follow-up, RENS resulted in a significant increase in fat free mass (47.4 ± 7.4 vs. 46.5 ± 7.4, = 0.046), the calf muscle circumference (36.4 ± 1.3 vs. 32.3 ± 4.3, = 0.025), and circulating irisin (3 ± 1.1 vs. 2.6 ± 1.3, = 0.030) compared to baseline. RE resulted in a significant increase in grip strength (17.2 ± 4.6 vs. 15.3 ± 4.6, = 0.011) and irisin (3.1 ± 0.8 vs. 2.4 ± 0.3, = 0.011) and decreased walking speed at different distance ( < 0.02). Opposite findings in these parameters were observed in control intervention. In line with these findings, the percent change of calf muscle circumference ( = 0.003) and fat free mass ( < 0.0001) were significantly increased in RENS compared to control, whereas fat mass ( = 0.033) was decreased. Interestingly, in this group, strength was positively correlated with fat free mass ( = 0.782, = 0.008), and circulating irisin was significantly decreased in those participants with strength loss at the end of the study ( = 0.002). No significant correlation between circulating irisin and myostatin in any group was observed.
Circulating irisin, but not myostatin, constitutes a marker for improved muscular performance in elderly subjects.
衰老作为一种生理过程，已知会引起身体成分的变化，影响肌肉组织并导致肌肉力量下降。运动时，肌肉作为内分泌器官发挥作用，产生并释放鸢尾素和肌肉生长抑制素等肌动蛋白，调节肌肉生长。在此，我们旨在评估低强度抗阻运动（无论是否补充蛋白质）对老年受试者身体成分、人体测量参数以及循环鸢尾素和肌肉生长抑制素的影响。
这是一项前瞻性对照临床试验，受试者被随机分为3组：（1）对照组（n = 20），（2）低强度抗阻运动组（RE）（n = 14），以及（3）低强度抗阻运动与营养支持组（RENS）（n = 9）。年龄在60 - 75岁的参与者在基线期及之后的16周接受研究。通过生物电阻抗评估身体成分。使用酶联免疫吸附测定法测量血清鸢尾素和肌肉生长抑制素。
随访时，与基线相比，RENS组的去脂体重显著增加（47.4 ± 7.4 vs. 46.5 ± 7.4，P = 0.046），小腿围显著增加（36.4 ± 1.3 vs. 32.3 ± 4.3，P = 0.025），循环鸢尾素显著增加（3 ± 1.1 vs. 2.6 ± 1.3，P = 0.030）。RE组握力显著增加（17.2 ± 4.6 vs. 15.3 ± 4.6，P = 0.011），鸢尾素显著增加（3.1 ± 0.8 vs. 2.4 ± 0.3，P = 0.011），不同距离的步行速度降低（P < 0.02）。在对照干预中观察到这些参数的相反结果。与这些结果一致，与对照组相比，RENS组小腿围（P = 0.003）和去脂体重（P < 0.0001）的百分比变化显著增加，而脂肪量减少（P = 0.033）。有趣的是，在该组中，力量与去脂体重呈正相关（r = 0.782，P = 0.008），并且在研究结束时力量下降的参与者中循环鸢尾素显著降低（P = 0.002）。在任何组中均未观察到循环鸢尾素与肌肉生长抑制素之间存在显著相关性。
循环鸢尾素而非肌肉生长抑制素是老年受试者肌肉性能改善的标志物。
