Impact of the high-molecular-weight form of adiponectin on endothelial function in healthy young men

Objective Adiponectin is an adipocyte-derived, antiatherogenic protein that is present in plasma as a large multimeric structure of high molecular weight (HMW) and in a trimer or hexamer form (non-HMW). The biological activities of these isoforms have not yet been elucidated. We therefore examined the effect of these isoforms on endothelial function in healthy young men. Design One hundred apparently healthy young men without overt cardiovascular disease (mean age 30 years) were recruited in this cross-sectional study based on voluntary enrolment. Measurements We evaluated endothelial function estimated by flow-mediated dilatation (FMD) of the brachial artery during reactive hyperaemia, and measured total and HMW adiponectin levels. Results Both HMW and non-HMW adiponectin levels showed a significant, inverse correlation with body mass index (BMI). FMD was significantly correlated with fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), malondialdehyde-modified low density lipoprotein (MDA-LDL), LDL particle size, and HMW adiponectin (r = 0.320, P = 0.001), but not non-HMW adiponectin (r = 0.125, P = 0.22). In multivariate analysis, HMW adiponectin and MDA-LDL were selected as independent factors capable of influencing FMD. No variables determined nitroglycerin-induced dilatation. Conclusions These results suggest that even in young men, plasma adiponectin levels can predict endothelial dysfunction before any overt vascular disease has occurred. HMW adiponectin may be more useful as a marker of endothelial dysfunction than total adiponectin.