Chrzanowski-Smith Oliver J, Edinburgh Robert M, Smith Eleanor, Thomas Mark P, Walhin Jean-Philippe, Koumanov Francoise, Williams Sean, Betts James A, Gonzalez Javier T
Department for Health, University of Bath, Bath, UK.
Centre for Nutrition, Exercise and Metabolism, University of Bath, Bath, UK.
Exp Physiol. 2021 May;106(5):1208-1223. doi: 10.1113/EP089431. Epub 2021 Mar 18.
What is the central question of this study? What is the relationship between proteins in skeletal muscle and adipose tissue determined at rest and at peak rates of fat oxidation in men and women? What is the main finding and its importance? The resting contents of proteins in skeletal muscle involved in triglyceride hydrolysis and mitochondrial lipid transport were more strongly associated with peak fat oxidation rates than proteins related to lipid transport or hydrolysis in adipose tissue. Although females displayed higher relative rates of fat oxidation than males, this was not explained by the proteins measured in this study, suggesting that other factors determine sex differences in fat metabolism.
We explored key proteins involved in fat metabolism that might be associated with peak fat oxidation (PFO) and account for sexual dimorphism in fuel metabolism during exercise. Thirty-six healthy adults [15 women; 40 ± 11 years of age; peak oxygen consumption 42.5 ± 9.5 ml (kg body mass) min ; mean ± SD] completed two exercise tests to determine PFO via indirect calorimetry. Resting adipose tissue and/or skeletal muscle biopsies were obtained to determine the adipose tissue protein content of PLIN1, ABHD5 (CGI-58), LIPE (HSL), PNPLA2 (ATGL), ACSL1, CPT1B and oestrogen receptor α (ERα) and the skeletal muscle protein content of FABP 3 (FABPpm), PNPLA2 (ATGL), ACSL1, CTP1B and ESR1 (ERα). Moderate strength correlations were found between PFO [in milligrams per kilogram of fat-free mass (FFM) per minute] and the protein content of PNPLA2 (ATGL) [r = 0.41 (0.03-0.68), P < 0.05] and CPT1B [r = 0.45 (0.09-0.71), P < 0.05] in skeletal muscle. No other statistically significant bivariate correlations were found consistently. Females had a greater relative PFO than males [7.1 ± 1.9 vs. 4.5 ± 1.3 and 7.3 ± 1.7 vs. 4.8 ± 1.2 mg (kg FFM) min in the adipose tissue (n = 14) and skeletal muscle (n = 12) subgroups, respectively (P < 0.05)]. No statistically significant sex differences were found in the content of these proteins. The regulation of PFO might involve processes relating to intramyocellular triglyceride hydrolysis and mitochondrial fatty acid transport, and adipose tissue is likely to play a more minor role than muscle. Sex differences in fat metabolism are likely to be attributable to factors other than the resting content of proteins in skeletal muscle and adipose tissue relating to triglyceride hydrolysis and fatty acid transport.
本研究的核心问题是什么？男性和女性在静息状态以及脂肪氧化峰值速率时，骨骼肌和脂肪组织中的蛋白质之间存在怎样的关系？主要发现及其重要性是什么？与甘油三酯水解及线粒体脂质转运相关的骨骼肌蛋白质静息含量，比脂肪组织中与脂质转运或水解相关的蛋白质，与脂肪氧化峰值速率的关联更为紧密。尽管女性的脂肪氧化相对速率高于男性，但本研究中所测定的蛋白质并不能解释这一现象，这表明其他因素决定了脂肪代谢中的性别差异。
我们探究了参与脂肪代谢的关键蛋白质，这些蛋白质可能与脂肪氧化峰值（PFO）相关，并解释运动期间燃料代谢中的性别差异。36名健康成年人[15名女性；年龄40±11岁；峰值耗氧量42.5±9.5毫升/（千克体重·分钟）；均值±标准差]完成了两项运动测试，通过间接量热法测定PFO。获取静息状态下的脂肪组织和/或骨骼肌活检样本，以测定脂肪组织中PLIN1、ABHD5（CGI - 58）、LIPE（HSL）、PNPLA2（ATGL）、ACSL1、CPT1B和雌激素受体α（ERα）的蛋白质含量，以及骨骼肌中FABP 3（FABPpm）、PNPLA2（ATGL）、ACSL1、CTP1B和ESR1（ERα）的蛋白质含量。发现PFO[每分钟每千克去脂体重（FFM）的毫克数]与骨骼肌中PNPLA2（ATGL）的蛋白质含量[r = 0.41（0.03 - 0.68），P < 0.05]和CPT1B的蛋白质含量[r = 0.45（0.09 - 0.71），P < 0.05]之间存在中等强度的相关性。未一致发现其他具有统计学意义的双变量相关性。女性的相对PFO高于男性[脂肪组织（n = 14）和骨骼肌（n = 12）亚组中分别为7.1±1.9与4.5±1.3以及7.3±1.7与4.8±1.2毫克/（千克FFM·分钟），P < 0.05]。这些蛋白质的含量未发现具有统计学意义的性别差异。PFO的调节可能涉及肌细胞内甘油三酯水解和线粒体脂肪酸转运相关的过程，并且脂肪组织可能比肌肉发挥的作用更小。脂肪代谢中的性别差异可能归因于骨骼肌和脂肪组织中与甘油三酯水解和脂肪酸转运相关的蛋白质静息含量之外的其他因素。
