Warren Jonathan L, Gower Barbara A, Hunter Gary R, Windham Samuel T, Moellering Douglas R, Fisher Gordon
Department of Nutrition Sciences, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294, USA.
Department of Human Studies, University of Alabama at Birmingham, 1720 2nd Avenue South, Birmingham, AL 35294, USA.
J Nutr Metab. 2017;2017:7832057. doi: 10.1155/2017/7832057. Epub 2017 Oct 24.
Higher fatty acid (FA) oxidation rates have been reported in obese individuals compared to lean counterparts; however whether this reflects a shift in substrate-specific oxidative capacity at the level of the skeletal muscle mitochondria has not been examined. The purpose of this study was to test the hypothesis that in situ measures of skeletal muscle mitochondria FA oxidation would be positively associated with total body fat. Participants were 38 premenopausal women (BMI = 26.5 ± 4.3 kg/m). Total and regional fat were assessed by dual-energy X-ray absorptiometry (DXA). Mitochondrial FA oxidation was assessed in permeabilized myofibers using high-resolution respirometry and a palmitoyl carnitine substrate. We found positive associations of total fat mass with State 3 (ADP-stimulated respiration) ( = 0.379, < 0.05) and the respiratory control ratio (RCR, measure of mitochondrial coupling) ( = 0.348, < 0.05). When participants were dichotomized by high or low body fat percent, participants with high total body fat displayed a higher RCR compared to those with low body fat ( < 0.05). There were no associations between any measure of regional fat and mitochondrial FA oxidation independent of total fat mass. In conclusion, greater FA oxidation in obesity may reflect molecular processes that enhance FA oxidation capacity at the mitochondrial level.
据报道，与瘦人相比，肥胖个体的高级脂肪酸（FA）氧化率更高；然而，这是否反映了骨骼肌线粒体水平上底物特异性氧化能力的转变尚未得到研究。本研究的目的是检验以下假设：骨骼肌线粒体FA氧化的原位测量值与全身脂肪呈正相关。研究对象为38名绝经前女性（BMI = 26.5 ± 4.3 kg/m²）。采用双能X线吸收法（DXA）评估全身和局部脂肪。使用高分辨率呼吸测定法和棕榈酰肉碱底物评估通透化肌纤维中的线粒体FA氧化。我们发现，总脂肪量与状态3（ADP刺激的呼吸）（r = 0.379，P < 0.05）和呼吸控制率（RCR，线粒体偶联指标）（r = 0.348，P < 0.05）呈正相关。当根据高或低体脂百分比将参与者分为两组时，高全身脂肪的参与者与低体脂的参与者相比，RCR更高（P < 0.05）。在不考虑总脂肪量的情况下，任何局部脂肪测量值与线粒体FA氧化之间均无关联。总之，肥胖中更高的FA氧化可能反映了在分子水平上增强线粒体FA氧化能力的过程。
