Adipose Insulin Resistance and Decreased Adiponectin Are Correlated With Metabolic Abnormalities in Nonobese Men

Abstract

Context: Adipose tissue dysfunction is characterized by decreased adiponectin (AN) levels and impaired adipose tissue insulin sensitivity (ATIS) and is associated with metabolic disorders. While Asians readily develop metabolic disease without obesity, it remains unclear how decreased AN level and impaired ATIS affect metabolic abnormalities in nonobese Asians.

Design and setting: To investigate the relationships between decreased AN level, impaired ATIS, and metabolic abnormalities, we studied 94 Japanese men whose body mass index was less than 25 kg/m2. We divided the subjects into 4 groups based on their median AN level and ATIS, the latter calculated as the degree of insulin-mediated suppression of free fatty acids during hyperinsulinemic euglycemic clamp, and compared the metabolic parameters in the 4 groups.

Results: The High-ATIS/High-AN group (n = 29) showed similar anthropometric data to the High-ATIS/Low-AN group (n = 18). In contrast, both the Low-ATIS/High-AN (n = 18) and Low-ATIS/Low-AN (n = 29) groups showed significantly lower muscle insulin sensitivity than the High-ATIS groups. The intrahepatic lipid level in the Low-ATIS/Low-AN group was significantly higher than that in the High-ATIS groups. In addition, the Low-ATIS/Low-AN group had a significantly higher fasting serum triglyceride level and significantly lower high-density lipoprotein cholesterol level than the other 3 groups.

Conclusions: In nonobese Japanese men with high ATIS, the AN level was not associated with metabolic characteristics. On the other hand, subjects with low ATIS showed reduced muscle insulin sensitivity, and those with a decreased AN level demonstrated multiple metabolic abnormalities, represented by fatty liver and dyslipidemia.

Keywords: adiponectin; dyslipidemia; ectopic fat; free fatty acid; insulin resistance; nonobese.