Decreased retinol binding protein 4 concentrations are associated with cholesterol gallstone disease

Circulating retinol binding protein 4 (RBP4) is associated with a variety of obesity-related diseases. This study investigated whether there were aberrant concentrations of RBP4 in cholesterol gallstone disease.

Serum RBP4 levels of 100 cholesterol gallstone patients and 147 healthy controls were measured by enzyme-linked immunosorbent assay and further correlated with clinical and biochemical characteristics, including insulin resistance and renal function. Gallstone specimens were obtained during laparoscopic cholecystectomy and analyzed for their chemical composition using Fourier transform infrared spectroscopy

Significantly lower serum RBP4 levels were found in patients with cholesterol gallstones in comparison with controls (30.57 +/- 13.64 mg/L vs. 41.52 +/- 20.25 mg/L, p<0.001). Lower serum RBP4 levels were also associated with gallstone occurrence (odds ratio = 0.93; 95% confidence interval = 0.88-0.96; p = 0.004). Serum RBP4 levels of all subjects were positively correlated with total cholesterol, triglyceride, creatinine, insulin resistance and albumin, and inversely correlated with aspartate aminotransferase and alanine aminotransferase. In multivariate analysis, cholesterol gallstone formation was significantly associated with a lower serum RBP4 level (odds ratio = 4.2; 95% confidence interval= 1.40-12.57; p = 0.010). RBP4 levels were significantly decreased regardless of renal function in patients with gallstones, but levels increased proportionate to renal dysfunction in people without gallstones.

Circulating RBP4 decreases in cholesterol gallstone disease independent of renal function. Further studies are needed to investigate the relationship between liver function and RBP4 levels in these patients.