Abstract：
Given the increased concerns about the degenerative decline in the physical performance of the elderly, there is a need for developing effective strategies to suppress the age-related loss of skeletal muscle mass and functional capacity through a lifestyle intervention. This randomized controlled trial examined whether a combination of Korean mistletoe extract (KME) supplement and exercise affected muscle mass, muscle function, and targeted molecular expressions. Sixty-seven subjects aged 55-75years were assigned to placebo, low-dose (1g/d), or high-dose (2g/d) of KME for 12weeks. The body composition was significantly changed in the high-dose group during the intervention period as determined by skeletal muscle mass (P=0.040), fat free mass (P=0.042), soft lean mass (P=0.023), skeletal muscle index (P=0.041), fat-free mass index (P=0.030), percent body fat (P=0.044), and fat mass to lean mass ratio (P=0.030). Knee strength was measured by Cybex, demonstrating a significant effect in the KME groups compared to the placebo group (P=0.026 for peak torque and P=0.057 for set total work), which was more pronounced after adjusting for age, gender, protein, and energy intake (P=0.009 for peak torque and P=0.033 for set total work). The dynamic balance ability was remarkably improved in the high-dose group over a 12-week period as determined by Timed \"Up and Go\" (P=0.005 for fast walk test and P=0.024 for ordinary walk test). Consistent with these results, RT-PCR, multiplex analyses, and immunocytofluorescence staining revealed that a high-dose KME supplementation was effective for suppressing intracellular pathways related to muscle protein degradation, but stimulating those related to myogenesis. In particular, significant differences were found in atrogin-1 mRNA (P=0.002 at a single administration and P=0.001 at a 12-week administration), myogenin mRNA (P<0.0001 at a single administration and P=0.040 at a 12-week administration), and insulin growth factor 1 receptor phosphorylation (P=0.002 at a 12-week administration). These results suggest that KME supplementation together with resistance exercise may be useful in suppressing the age-related loss of muscle mass and strength in the elderly.
摘要：
鉴于人们对老年人身体机能退化性下降的担忧日益增加，需要制定有效的策略,通过生活方式干预来抑制与年龄相关的骨骼肌质量和功能丧失.这项随机对照试验检查了韩国槲寄生提取物（KME）补充剂和运动的组合是否会影响肌肉质量，肌肉功能，和有针对性的分子表达。67名55-75岁的受试者被分配到安慰剂组，低剂量（1g/d），或高剂量（2g/d）的KME持续12周。高剂量组在干预期间的身体成分发生了显着变化，如骨骼肌质量（P=0.040），无脂肪质量（P=0.042），软贫质量(P=0.023)，骨骼肌指数（P=0.041），无脂质量指数（P=0.030），体脂百分比（P=0.044），脂肪质量与瘦体重比(P=0.030)。膝关节强度是用Cybex测量的,与安慰剂组相比，KME组具有显着效果（峰值扭矩P=0.026，总功P=0.057），这在调整了年龄后更加明显，性别,蛋白质，和能量摄入（峰值扭矩P=0.009，设定总功P=0.033）。通过Timed\“UpandGo”确定，高剂量组的动态平衡能力在12周内得到了显着改善（快速步行试验P=0.005，普通步行试验P=0.024）。与这些结果一致，RT-PCR,多元分析，和免疫荧光染色显示，高剂量的KME补充剂对抑制与肌肉蛋白降解相关的细胞内途径是有效的，而是刺激那些与肌生成有关的。特别是,在atrogin-1mRNA中发现了显着差异（单次给药时P=0.002，12周给药时P=0.001），肌生成素mRNA（单次给药时P<0.0001，12周给药时P=0.040），和胰岛素生长因子1受体磷酸化（12周给药P=0.002）。这些结果表明，补充KME和抗阻运动可能有助于抑制老年人与年龄相关的肌肉质量和力量损失。
