The relationship between retinol-binding protein 4 and apolipoprotein B-containing lipoproteins is attenuated in patients with very high serum triglycerides: A pilot study.

OBJECTIVE The investigation of the association between retinol-binding protein 4 (RBP4) and lipoproteins in subjects with hypertriglyceridemia. DESIGN Forty-six obese or overweight hypertriglyceridemic patients were studied at baseline and 20 of them underwent a hypocaloric low-fat diet for 3 months. RESULTS Plasma RBP4 levels were positively correlated with serum triglycerides (TG) in the subgroup of patients with TG <200 mg/dL (r=0.453, p=0.039) and negatively correlated with TG in patients with TG ≥200 mg/dL (r=-0.487, p=0.019). In the subgroup with TG <200 mg/ dL, subjects with circulating RBP4 above the median 46 mg/L had higher levels of intermediate density lipoprotein-cholesterol (IDL-C), low-density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (ApoB), while these differences were absent in patients with TG ≥200 mg/dL. The associations of percentage changes of circulating RBP4 with the percentage changes of LDL-C, very low-density lipoprotein-cholesterol (VLDL-C) and ApoB were positive after the first month and 3 months of diet for patients with baseline TG <200 mg/dL, while no correlations existed for patients with TG ≥200 mg/dL. CONCLUSIONS The positive association between circulating RBP4 and ApoB-containing lipoproteins in a steady metabolic state, as well as during a hypocaloric diet, appears to be attenuated in patients with very high TG.