Muscle Laboratory, Royal Brompton Hospital & NHLI, Imperial College, London, UK.
Eur Respir J. 2009 Dec;34(6):1429-35. doi: 10.1183/09031936.00074008. Epub 2009 May 14.
Quadriceps muscle weakness is an important component of chronic obstructive pulmonary disease (COPD). We hypothesised that quadriceps weakness would also be a feature of restrictive lung disease due to scoliosis. We studied 10 patients with severe scoliosis (median (interquartile range (IQR)) forced expiratory volume in 1 s (FEV(1))() 35.3 (11)% predicted), 10 patients with severe COPD (FEV(1) 26.5 (9.0)% pred) and 10 healthy age-matched adults. We measured quadriceps strength, exercise capacity and analysed quadriceps muscle biopsies for myosin heavy-chain (MyHC) isoform expression and the presence of oxidative stress. Both groups exhibited quadriceps weakness with median (IQR) maximal voluntary contraction force being 46.0 (17.0) kg, 21.5 (21.0) kg and 31.5 (11.0) kg, respectively (p = 0.02 and 0.04, respectively, for each patient group against controls). Oxidative stress was significantly greater in the quadriceps of both restrictive and COPD patients. The scoliosis patients exhibited a decrease in the proportion of MyHC type I compared with controls; median (IQR) 35.3 (18.5)% compared with 47.7 (9.3)%, p = 0.028. The scoliosis patients also showed an increase in MyHC IIx (26.3 (15.5)% compared with 11.3 (13.0)%, p = 0.01. Quadriceps weakness is a feature of severe scoliosis; the similarities between patients with scoliosis and patients with COPD suggest a common aetiology to quadriceps weakness in both conditions.
股四头肌无力是慢性阻塞性肺疾病（COPD）的一个重要组成部分。我们假设，由于脊柱侧凸导致的限制性肺病也会出现股四头肌无力的特征。我们研究了 10 例严重脊柱侧凸（中位（四分位间距（IQR））用力肺活量在 1 秒内（FEV1）（）35.3（11）%预测），10 例严重 COPD（FEV1 26.5（9.0）%预）和 10 名年龄匹配的健康成年人。我们测量了股四头肌力量、运动能力，并分析了股四头肌肌肉活检的肌球蛋白重链（MyHC）同工型表达和氧化应激的存在。两组均表现出股四头肌无力，最大自愿收缩力中位数（IQR）分别为 46.0（17.0）kg、21.5（21.0）kg和 31.5（11.0）kg（p=0.02 和 0.04，分别为每个患者组与对照组相比）。氧化应激在限制性肺病和 COPD 患者的股四头肌中明显更大。脊柱侧凸患者的 MyHC 型 I 比例与对照组相比明显降低；中位数（IQR）为 35.3（18.5）%，而对照组为 47.7（9.3）%，p=0.028。脊柱侧凸患者还显示出 MyHC IIx 的增加（26.3（15.5）%，而对照组为 11.3（13.0）%，p=0.01）。股四头肌无力是严重脊柱侧凸的特征；脊柱侧凸患者和 COPD 患者之间的相似之处表明，两种情况下股四头肌无力的病因相同。
