Relationship Between Retinol-Binding Protein-4/Adiponectin and Leptin/Adiponectin Ratios with Insulin Resistance and Inflammation

Background: There is much data supporting a role for adipokines in both obesity and metabolic syndrome. Insulin resistance and low-grade inflammation are crucial in the genesis of both disorders. Although data suggest that the ratio of leptin/adiponectin correlates with insulin resistance and predicts cardiovascular disease (CVD), there is scanty data on the relationship between the retinol-binding protein-4 (RBP4)/adiponectin ratio with insulin resistance and inflammation. We tested the relationship of both these ratios with measures of insulin resistance and inflammation. Methods: In 72 individuals, including controls and patients with metabolic syndrome, we calculated the homeostasis model assessment of insulin resistance (HOMA-IR) and assayed high-sensitivity C-reactive protein (hsCRP) and the adipokines, adiponectin, leptin, and RBP4. Results: Whereas both the leptin/adiponectin and RBP4/adiponectin ratios did not correlate with HOMA-IR, both correlated significantly with the prototypic biomarker of inflammation, hsCRP. Also in patients with metabolic syndrome following adjustment for adiposity, only the RBP4/adiponectin ratio was significantly increased. Conclusions: Hence it appears that whereas both the leptin/adiponectin and RBP4/adiponectin ratios correlate with inflammation, only the RBP4/adiponectin ratio was significantly increased in metabolic syndrome and would be more useful to predict CVD, especially in metabolic syndrome.