Association of a Novel Adipokine with Insulin Resistance and Disease Severity in HCV Infected Patients

Abstract

Retinol-binding protein 4 (RBP4) has been identified as a protein contributing to insulin resistance (IR). As insulin resistance is present in nearly all patients with liver cirrhosis, we evaluated RBP4 in patients with chronic hepatitis C virus infected patients (CHC). This study aimed to evaluate the role of serum retinol binding protein 4 (RBP-4) as a predictor for early detection of insulin resistance (IR) in patients with CHC infection. Research Design and Methods: Serum RBP4 was measured in 60 non diabetic CHC Patients classified according to Child- Pugh classification (Child A, Child B, Child C), 20 diabetic CHC patients and 20 age- and sex-matched healthy blood donors served as control subjects. RBP-4 correlation with the homeostasis model assessment of insulin resistance index (HOMA-IR) and metabolic factors was investigated. Results: Serum RBP-4 levels were significantly lower in HCV infected patients and HCV diabetic patients compared with controls (HCV 16545.17± 10633.16, Diabetic HCV 10310 ± 4371.31, Control 27820.0 ± 9316.46, P< 0.001). In addition, serum levels of RBP-4 significantly decreased between all stages of cirrhosis, with the lowest level in Child C. HOMA-IR not significantly higher in HCV infected patients compared to control (HCV 5.54 ± 3.67, and Control 4.11 ± 2.42). RBP-4 levels correlate positively with GGT (P<0.01), CHOL (P<0.05) and TG (P<0.05) in HCV Child C, additionally, it shows significant positive correlation with TG (P< 0.05) in HCV Child B. Conclusions: Disease severity may limit the role of RBP4 as a predictor of IR in CHC. These data demonstrate that RBP4 in CHC patients decreased due to reduced hepatic production, and it is not associated with insulin resistance. Keywords: HCV, RBP4, Insulin Resistance Abbreviations: RBP4: Retinol-binding protein 4, IR: insulin resistance, HOMA-IR: homeostasis model assessment of insulin resistance index, CHC: Chronic Hepatitis C Virus.