ObjectiveThe objective of this study was to examine the hypothesis that abdominal and gluteal adipocyte turnover, lipid dynamics, and fibrogenesis are dysregulated among insulin‐resistant (IR) compared with insulin‐sensitive (IS) adolescents with obesity.MethodsSeven IS and seven IR adolescents with obesity participated in a 3‐h oral glucose tolerance test and a multi‐section magnetic resonance imaging scan of the abdominal region to examine body fat distribution patterns and liver fat content. An 8‐week 70% deuterated water (2H2O) labeling protocol examined adipocyte turnover, lipid dynamics, and fibrogenesis in vivo from biopsied abdominal and gluteal fat.ResultsAbdominal and gluteal subcutaneous adipose tissue (SAT) turnover rates of lipid components were similar among IS and IR adolescents with obesity. However, the insoluble collagen (type I, subunit α2) isoform measured from abdominal, but not gluteal, SAT was elevated in IR compared with IS individuals. In addition, abdominal insoluble collagen Iα2 was associated with ratios of visceral‐to‐total (visceral adipose tissue + SAT) abdominal fat and whole‐body and adipose tissue insulin signaling, and it trended toward a positive association with liver fat content.ConclusionsAltered extracellular matrix dynamics, but not expandability, potentially decreases abdominal SAT lipid storage capacity, contributing to the pathophysiological pathways linking adipose tissue and whole‐body IR with altered ectopic storage of lipids within the liver among IR adolescents with obesity.

中文翻译：

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细胞外基质动力学改变与肥胖青少年儿童的胰岛素抵抗相关

目的本研究的目的是检验以下假设：与胰岛素敏感 (IS) 肥胖青少年相比，胰岛素抵抗 (IR) 青少年的腹部和臀肌脂肪细胞更新、脂质动态和纤维形成失调。 方法 7 名 IS 和 7 名 IR 青少年肥胖者参加了 3 小时口服葡萄糖耐量试验和腹部多断面磁共振成像扫描，以检查身体脂肪分布模式和肝脏脂肪含量。8 周 70% 氘化水（2H2O) 标记方案检查了腹部和臀部脂肪活检的体内脂肪细胞周转率、脂质动态和纤维发生。结果 IS 和 IR 肥胖青少年的腹部和臀部皮下脂肪组织 (SAT) 脂质成分周转率相似。然而，与 IS 个体相比，IR 个体中从腹部（而非臀肌）测量到的不溶性胶原蛋白（I 型，亚基 α2）亚型 SAT 升高。此外，腹部不溶性胶原蛋白 Iα2 与内脏与总腹部脂肪（内脏脂肪组织 + SAT）的比率以及全身和脂肪组织胰岛素信号传导相关，并且与肝脏脂肪含量呈正相关。 结论基质动力学而非可扩展性可能会降低腹部 SAT 脂质储存能力，从而促成将脂肪组织和全身 IR 与肥胖 IR 青少年肝脏内脂质异位储存改变联系起来的病理生理学途径。