Does adiponectin level explain the atherogenic properties of Hp 2-2 phenotype in type 2 diabetic patients?

Objectives: Haptoglobin (Hb) and adiponectin are antioxidant proteins and independent predictors of atherosclerotic vascular disease in diabetic patients. The link between Hp phenotype and circulating adiponectin levels were examined.

Methods: Diabetic patients were divided into two groups by Hp phenotype: Hp 2-2 group and non-Hp 2-2 group (Hp 2-1 and Hp 1-1). Blood glucose, HbA1C, insulin, lipids, CRP, HOMA-IR, 25OH vitamin D, leptin and adiponectin levels were measured. Pulse wave velocity (PWV) was performed using SphygmoCor (version 7.1, AtCor Medical, Sydney, Australia).

Results: PWV was significantly higher in patients homozygous for the 2 allele (Hp 2-2) compared to non-Hp 2-2 patients (Hp 1-1 and Hp 1-2), p < 0.0001. Adiponectin was significantly lower in Hp 2-2 patients than in non-Hp 2-2 group (p < 0.016). Neither leptin nor the leptin adiponectin ratio (LAR) differed significantly between groups.

Conclusions: PWV was significantly higher and plasma adiponectin levels were significantly lower in diabetic patients homozygous for the 2 allele (Hp 2-2). These differences were detected despite the lack of by-phenotype differences in glycemic control, blood pressure level or presence of cardiovascular risk factor and suggest an active role of adiponectin in the pathophysiology of vascular disease in this population.