Effect of adiponectin on carotid arterial stiffness in type 2 diabetic patients treated with pioglitazone and metformin

Adiponectin, an adipocyte-specific plasma protein, has been reported to exhibit protective effects against atherosclerosis as well as an insulin-sensitizing effect. This study was designed to investigate the effect of adiponectin on carotid arterial stiffness in type 2 diabetic patients treated with pioglitazone and metformin. Twenty type 2 diabetic patients were enrolled and divided into 2 groups, a pioglitazone-treated group (n = 10) and a metformin-treated group (n = 10). Before and after intervention, plasma adiponectin levels were measured by enzyme-linked immunosorbent assay and carotid arterial stiffness was evaluated by the stiffness parameter beta, measured by ultrasound equipped with a phase-locked echo-tracking system. In the pioglitazone group, plasma adiponectin level significantly increased and stiffness parameter beta significantly decreased, whereas in the metformin group neither of these parameters changed significantly. The changes in stiffness parameter beta were significantly and inversely correlated with change in plasma adiponectin level after treatment with pioglitazone or metformin in the group of all subjects (r = -0.472, P = .036). In conclusion, the present study is the first to demonstrate that increase in adiponectin level after treatment with the insulin sensitizers pioglitazone and metformin may improve arterial stiffness in patients with type 2 diabetes mellitus. (c) 2006 Elsevier Inc. All rights reserved.