Increased levels of retinol binding protein 4 in patients with advanced heart failure correct after hemodynamic improvement through ventricular assist device placement

Background: Chronic heart failure is associated with higher risk for developing diabetes mellitus. Secretory products from adipocytes may contribute to the deterioration in glycemic control and increased insulin resistance (IR). Retinol binding protein 4 (RBP4) is an adipose tissue-derived protein with pro-diabetogenic effects. The aim of the present study was to investigate the relationship of RBP4 in patients with heart failure. Methods and Results: Serum levels of RBP4, insulin, and fasting glucose were assessed in 58 patients with severe heart failure at the time of left ventricular assist device (LVAD) implantation and in 44 patients at the time of explantation, as well as in 10 normal control subjects. Serum RBP4 levels were measured by specific enzyme-linked immunosorbent assay, and IR was assessed using the homeostatic model of IR (HOMA-IR). Fasting glucose, insulin and HOMA-IR were significantly higher in patients at the time of LVAD implantation compared to controls (all P<0.01). RBP-4 and HOMA-IR significantly decreased after LVAD implantation (21.7±8.8 mg/dl to 16.0±3.8 mg/dl, P<0.05; 4.2±2.7 to 2.5±2.0, P<0.01). Conclusions: Patients with advanced heart failure have increased levels of RBP4, and LVAD implantation reduces RBP4. These findings implicate RBP4 in the cascade of reversible metabolic derangements in advanced heart failure.