In an aging society, late‐life depression has become an increasing problem. There is evidence that physical activity ameliorates depressive symptoms and increases the quality of life (QoL). However, the underlying mechanisms are still poorly understood. Myokines are molecules secreted in response to muscle contraction. Some of them can cross the blood‐brain barrier, making them promising candidates for mediating the beneficial effects of physical activity on mood. The present study aims to compare circulating myokine levels to depression/QoL in older athletes and controls. 55 athletes, 57 controls >59 years were enrolled. The assessment included ergometry, magnetic resonance imaging, blood withdrawal, and neuropsychological testing. Serum interleukin‐6 (IL‐6), irisin, brain‐derived neurotrophic factor (BDNF), kynurenine, and cathepsin B were analyzed and compared to surrogates of depression and quality of life. Athletes presented with higher levels of Cathepsin B. Among controls, all myokines but irisin were associated with age. Also, among controls, kynurenine and IL‐6 correlated inversely with specific dimensions of quality of life questionnaires, and IL‐6 further with depressive symptoms and decreased physical performance. No such associations could be found among athletes. Irisin levels were inversely associated with mild depression and low‐grade white matter‐lesions in the brain and predicted impaired QoL. The circulating levels of several myokines/muscle activity‐related factors appear to be associated with depressive symptoms and impaired QoL among older adults. However, in athletes, some of these connections seem ameliorated, suggesting additional stressors (as f.e. age) or a different pathomechanism among athletes.

中文翻译：

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基础肌因子水平与老年人的生活质量和抑郁情绪有关

在老龄化社会，晚年抑郁症已成为一个日益严重的问题。有证据表明，体育锻炼可以改善抑郁症状并提高生活质量 (QoL)。然而，潜在的机制仍然知之甚少。肌动蛋白是响应肌肉收缩而分泌的分子。其中一些可以穿过血脑屏障，使它们成为调节身体活动对情绪的有益影响的有希望的候选者。本研究旨在比较老年运动员和对照组的循环肌因子水平与抑郁/生活质量。55 名运动员，57 名对照组 > 59 岁。评估包括测力计、磁共振成像、抽血和神经心理学测试。血清白细胞介素-6 (IL-6)、鸢尾素、脑源性神经营养因子 (BDNF)、犬尿氨酸、和组织蛋白酶 B 进行了分析，并与抑郁症和生活质量的替代指标进行了比较。运动员表现出较高水平的组织蛋白酶 B。在对照组中，除鸢尾素外的所有肌细胞因子都与年龄相关。此外，在对照组中，犬尿氨酸和 IL-6 与生活质量问卷的特定维度呈负相关，IL-6 与抑郁症状和体能下降进一步相关。在运动员中找不到这样的关联。鸢尾素水平与轻度抑郁和脑部低度白质病变呈负相关，并预测生活质量受损。几种肌动蛋白/肌肉活动相关因子的循环水平似乎与老年人的抑郁症状和生活质量受损有关。然而，在运动员中，其中一些联系似乎得到了改善，