Shields Gregory Samuel, Coissi Graziele S, Jimenez-Royo Pilar, Gambarota Giulio, Dimber Rahul, Hopkinson Nicholas S, Matthews Paul M, Brown Andrew P, Polkey Michael I
Clinical Imaging Centre, GlaxoSmithKline Research and Development, Hammersmith Hospital, London, UK.
Muscle Nerve. 2015 Feb;51(2):214-21. doi: 10.1002/mus.24289. Epub 2014 Nov 19.
Chronic obstructive pulmonary disease (COPD) is associated with metabolic abnormalities in muscles of the lower limbs, but it is not known whether these abnormalities are generalized or limited to specific muscle groups, nor is there an easy way of predicting their presence.
Metabolism in the quadriceps and biceps of 14 COPD patients and controls was assessed during sustained contraction using 31-phosphorus magnetic resonance spectroscopy ((31) P MRS). T1 MRI was used to measure quadriceps intermuscular adipose tissue (IMAT).
COPD patients had prolonged quadriceps phosphocreatine time (patients: 38.8 ± 12.7 s; controls: 25.2 ± 10.6 s; P = 0.006) and a lower pH (patents: 6.88 ± 0.1; controls: 6.99 ± 0.06; P = 0.002). Biceps measures were not significantly different. IMAT was associated with a nadir pH <7.0 (area under the curve = 0.84).
Anaerobic metabolism during contraction was characteristic of quadriceps, but not biceps, muscles of patients with COPD and was associated with increased IMAT. Because IMAT can be assessed quickly by conventional MRI, it may be a useful approach for identifying patients with abnormal muscle bioenergetics.
慢性阻塞性肺疾病（COPD）与下肢肌肉的代谢异常有关，但尚不清楚这些异常是全身性的还是局限于特定肌肉群，也没有一种简单的方法来预测它们的存在。
使用31-磷磁共振波谱（（31）P MRS）评估14例COPD患者和对照组在持续收缩过程中股四头肌和肱二头肌的代谢情况。采用T1 MRI测量股四头肌肌间脂肪组织（IMAT）。
COPD患者股四头肌磷酸肌酸时间延长（患者：38.8±12.7秒；对照组：25.2±10.6秒；P = 0.006），pH值较低（患者：6.88±0.1；对照组：6.99±0.06；P = 0.002）。肱二头肌的测量结果无显著差异。IMAT与最低pH<7.0相关（曲线下面积 = 0.84）。
收缩过程中的无氧代谢是COPD患者股四头肌而非肱二头肌的特征，并且与IMAT增加有关。由于IMAT可以通过传统MRI快速评估，它可能是识别肌肉生物能量学异常患者的有用方法。
