Engelen M P K J, Orozco-Levi M, Deutz N E P, Barreiro E, Hernández N, Wouters E F M, Gea J, Schols A M W J
Dept of Respiratory Medicine, University Hospital Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands.
Eur Respir J. 2004 Apr;23(4):545-51. doi: 10.1183/09031936.04.00022204.
Recently, decreased glutamate (Glu) and reduced glutathione (GSH) levels were reported in the quadriceps femoris of patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to investigate whether Glu and GSH levels are also modified in the diaphragm of these patients. Nine male COPD patients (forced expiratory volume in one second (FEV1) range 28-68% of the predicted value) and seven male patients with normal pulmonary function (mean +/- SD FEV1 86 +/- 3% pred) submitted to thoracotomy were included. Biopsy specimens were taken from the diaphragm (both groups) and the quadriceps femoris (COPD group alone) in order to assess fibre size, myosin heavy chain expression, GSH levels and amino acid profile. The COPD group was characterised by preserved fibre size, a higher proportion of type I fibres (mean +/- SEM 70 +/- 3 versus 26 +/- 4%), and higher Glu and GSH content in the diaphragm compared to the quadriceps muscle. However, Glu and GSH levels were similar in diaphragm from the COPD and control groups. Glu level correlated with GSH level in both muscles. No significant correlation was found between Glu or GSH level and fibre size or proportions. This study shows that glutamate and reduced glutathione levels are preserved in the diaphragm of chronic obstructive pulmonary disease patients. Alterations in glutamate and reduced glutathione metabolism are muscle-specific in chronic obstructive pulmonary disease, affecting the quadriceps femoris but not the diaphragm. Glutamate and reduced glutathione levels are strongly interrelated in both muscles, independent of fibre type distribution and fibre size.
最近有报道称，慢性阻塞性肺疾病（COPD）患者的股四头肌中谷氨酸（Glu）水平降低，谷胱甘肽（GSH）水平也降低。本研究的目的是调查这些患者的膈肌中Glu和GSH水平是否也发生改变。纳入了9名接受开胸手术的男性COPD患者（一秒用力呼气量（FEV1）为预测值的28 - 68%）和7名肺功能正常的男性患者（平均±标准差FEV1为86±3%预测值）。为了评估纤维大小、肌球蛋白重链表达、GSH水平和氨基酸谱，从两组患者的膈肌以及仅COPD组患者的股四头肌中获取活检标本。COPD组的特点是纤维大小保持不变，I型纤维比例较高（平均±标准误为70±3%对26±4%），与股四头肌相比，膈肌中的Glu和GSH含量更高。然而，COPD组和对照组膈肌中的Glu和GSH水平相似。在两块肌肉中，Glu水平与GSH水平相关。未发现Glu或GSH水平与纤维大小或比例之间存在显著相关性。本研究表明，慢性阻塞性肺疾病患者的膈肌中谷氨酸和还原型谷胱甘肽水平保持不变。慢性阻塞性肺疾病中谷氨酸和还原型谷胱甘肽代谢的改变具有肌肉特异性，影响股四头肌但不影响膈肌。在两块肌肉中，谷氨酸和还原型谷胱甘肽水平密切相关，与纤维类型分布和纤维大小无关。
