Adipose Tissue Collagen and Inflammation in Nonobese Asian Indian Men

Objective: Obesity is thought to be the driving force for activation of adipose tissue (AT) collagen production and inflammation as well as systemic insulin resistance. The objective of this study was to determine whether these AT abnormalities can be found independent of obesity in the presence of systemic insulin resistance. Research Design and Methods: Thirty-eight normoglycemic men (14 Asian Indians and 24 white) were enrolled in the study and matched for age, body mass index, and total body fat. Subjects underwent anthropometric measurement, total body fat determination by underwater weighing, euglycemic-hyperinsulinemic clamps, and abdominal sc AT biopsy for mRNA extraction and gene expression determination. Fasting blood was collected for adipokine measurements. Results: Both groups were matched for age, body mass index, and percentage of total body fat. Subcutaneous abdominal AT mRNA expression was significantly higher for Col6a3 as well as genes associated with inflammation, CD68, MAC1, and MCP1 in Asian Indians compared with whites. Asian Indian men had significantly lower rates of glucose disposal and lower plasma adiponectin concentration. Plasma high-sensitivity C-reactive protein levels showed a trend towards higher levels in Asian Indian men. Conclusions: Increased col6a3 and macrophage infiltration in AT along with increased systemic insulin resistance is present independent of body fat content in young Asian Indian men, thus suggesting that AT dysfunction associates with systemic insulin resistance regardless of AT mass.