Adiponectin is associated with improvement of endothelial function after rosiglitazone treatment in non-diabetic individuals with metabolic syndrome

Objective The risks of metabolic syndrome (MetSyn) rely on the interaction between insulin resistance, metabolic abnormalities, inflammation and vascular dysfunction. Insulin sensitizers counteract some of these abnormalities. The objective of this study was to evaluate the effects of rosiglitazone (ROSI) on vascular reactivity, adipokines and inflammatory markers in a group of non-diabetic subjects with MetSyn. Methods and results Thirty subjects with NCEP-ATPIII criteria for MetSyn and eight healthy subjects were studied at baseline and 18 subjects with MetSyn were treated with ROSI 8 mg/day for 24 weeks. Venous occlusion plethysmography exams before and during intra-arterial infusions of acetylcholine and sodium nitroprusside were performed to assess endothelial-dependent and independent vasodilation. Forearm blood flow (FBF) and vascular resistance (VR) responses were analyzed. Treatment with ROSI improved endothelial function (235% increment in FBF; p < 0.01 and 56% decrement in VR; p = 0.01), adiponectin (7.3[3.6–17.9] versus 37.9[19.3–42.4]; p < 0.01), HOMA-IR (3.5 ± 1.2 versus 2.7 ± 1.6; p < 0.05), C-reactive protein (CRP) (1.05[0.57–2.07] versus 0.3[0.2–0.8]; p < 0.01) and fibrinogen (3.1 ± 0.73 versus 2.62 ± 0.64; p < 0.05) levels. The difference between groups on endothelial-dependent vasodilation, adiponectin and CRP levels disappeared after treatment and the improvement of endothelial function was associated with the increment of adiponectin levels. Conclusion ROSI treatment restored endothelial function in MetSyn subjects, probably through an adiponectin-mediated process.