Kramer Irene Fleur, Snijders Tim, Smeets Joey S J, Leenders Marika, van Kranenburg Janneau, den Hoed Marcel, Verdijk Lex B, Poeze Martijn, van Loon Luc J C
Department of Human Movement Sciences.
Department of Surgery, Division of Trauma Surgery.
J Gerontol A Biol Sci Med Sci. 2017 Oct 1;72(10):1369-1375. doi: 10.1093/gerona/glw253.
Sarcopenia, or the loss of muscle mass and strength, is known to increase the risk for falls and (hip) fractures in older people. The objective of this study was to assess the skeletal muscle fiber characteristics in elderly female hip fracture patients.
Percutaneous needle biopsies were collected from the vastus lateralis muscle in 15 healthy young women (20 ± 0.4 years), 15 healthy elderly women (79 ± 1.7 years), and 15 elderly women with a fall-related hip fracture (82 ± 1.5 years). Immunohistochemical analyses were performed to assess Type I and Type II muscle fiber size, and myonuclear and satellite cell content.
Type II muscle fiber size was significantly different between all groups (p < .05), with smaller Type II muscle fibers in the hip fracture patients (2,609 ± 185 µm2) compared with healthy elderly group (3,723 ± 322 µm2) and the largest Type II muscle fibers in the healthy young group (4,755 ± 335 µm2). Furthermore, Type I muscle fiber size was significantly lower in the hip fracture patients (4,684 ± 211 µm2) compared with the healthy elderly group (5,842 ± 316 µm2, p = .02). The number of myonuclei per Type II muscle fiber was significantly lower in the healthy elderly and hip fracture group compared with the healthy young group (p = .011 and p = .002, respectively). Muscle fiber satellite cell content did not differ between groups.
Elderly female hip fracture patients show extensive Type II muscle fiber atrophy when compared with healthy young or age-matched healthy elderly controls. Type II muscle fiber atrophy is an important hallmark of sarcopenia and may predispose to falls and (hip) fractures in the older population.
肌肉减少症，即肌肉质量和力量的丧失，已知会增加老年人跌倒和（髋部）骨折的风险。本研究的目的是评估老年女性髋部骨折患者的骨骼肌纤维特征。
从15名健康年轻女性（20±0.4岁）、15名健康老年女性（79±1.7岁）和15名与跌倒相关的髋部骨折老年女性（82±1.5岁）的股外侧肌采集经皮针吸活检样本。进行免疫组织化学分析以评估I型和II型肌纤维大小以及肌核和卫星细胞含量。
所有组之间II型肌纤维大小存在显著差异（p<0.05），髋部骨折患者的II型肌纤维（2,609±185μm²）比健康老年组（3,723±322μm²）小，而健康年轻组的II型肌纤维最大（4,755±335μm²）。此外，髋部骨折患者的I型肌纤维大小（4,684±211μm²）显著低于健康老年组（5,842±316μm²，p = 0.02）。与健康年轻组相比，健康老年组和髋部骨折组中每个II型肌纤维的肌核数量显著更低（分别为p = 0.011和p = 0.002）。各组之间肌纤维卫星细胞含量没有差异。
与健康年轻或年龄匹配的健康老年对照组相比，老年女性髋部骨折患者表现出广泛的II型肌纤维萎缩。II型肌纤维萎缩是肌肉减少症的一个重要标志，可能使老年人群更容易发生跌倒和（髋部）骨折。
