Satta A, Migliori G B, Spanevello A, Neri M, Bottinelli R, Canepari M, Pellegrino M A, Reggiani C
Division of Pneumology, Fondazione Salvatore Maugeri, IRCCS, Rehabilitation Institute of Tradate, Italy.
Eur Respir J. 1997 Dec;10(12):2853-60. doi: 10.1183/09031936.97.10122853.
This study aimed to investigate the relationship between skeletal muscle, fibre type composition, functional respiratory impairment and exercise tolerance in patients with moderate to severe chronic obstructive pulmonary disease (COPD). A group of 22 COPD patients and 10 healthy control subjects were studied. In COPD patients, vital capacity (VC) and forced expiratory volume in one second (FEV1) were reduced to 79% and 51%, respectively. Diffusion indices (transfer factor of the lung for carbon monoxide (TL,CO) and carbon monoxide transfer coefficient (KCO)) were also reduced. Arterial oxygen tension (Pa,O2) was normal or slightly altered. A maximal exercise test was performed and anaerobic threshold was calculated. Muscle samples from vastus lateralis were obtained by needle biopsy. Myosin heavy chain (MHC) and light chain (MLC) isoforms were separated by gel electrophoresis and quantified by densitometry. MHC isoforms were considered as molecular markers of fibre types. The proportion of the fast MHC-2B isoform was increased in COPD patients. TL,CO, KCO, VC and FEV1 were positively correlated with slow MHC isoform content. TL,CO and KCO were also negatively correlated with the content of the fast MHC-2B isoform. No correlation was found between exercise parameters and MHC isoform composition. The co-ordinated expression between MHC and MLC isoforms was altered in COPD patients. We conclude that reduced oxygen availability, probably in combination with muscle disuse, may determine muscle alterations in chronic obstructive pulmonary disease patients. The altered correlations between myosin heavy chain and light chain isoforms suggest that co-ordinated protein expression is lost in chronic obstructive pulmonary disease muscles.
本研究旨在调查中重度慢性阻塞性肺疾病（COPD）患者骨骼肌、纤维类型组成、功能性呼吸障碍与运动耐力之间的关系。研究了一组22例COPD患者和10名健康对照者。在COPD患者中，肺活量（VC）和一秒用力呼气容积（FEV1）分别降至79%和51%。弥散指标（肺一氧化碳转运因子（TL,CO）和一氧化碳转运系数（KCO））也降低。动脉血氧分压（Pa,O2）正常或略有改变。进行了最大运动试验并计算了无氧阈值。通过针吸活检获取股外侧肌的肌肉样本。通过凝胶电泳分离肌球蛋白重链（MHC）和轻链（MLC）同工型，并通过密度测定法定量。MHC同工型被视为纤维类型的分子标志物。COPD患者中快速MHC-2B同工型的比例增加。TL,CO、KCO、VC和FEV1与慢速MHC同工型含量呈正相关。TL,CO和KCO也与快速MHC-2B同工型的含量呈负相关。未发现运动参数与MHC同工型组成之间存在相关性。COPD患者中MHC和MLC同工型之间的协同表达发生了改变。我们得出结论，氧供应减少，可能与肌肉废用相结合，可能决定了慢性阻塞性肺疾病患者的肌肉改变。肌球蛋白重链和轻链同工型之间改变的相关性表明，慢性阻塞性肺疾病肌肉中协同蛋白表达丧失。
