Objectives The retinol binding protein 4 (RBP4) has recently been described as a protein highly related with insulin resistance (IR) states like obesity and diabetes. The chronic inflammatory states, like in rheumatoid arthritis (RA), are linked also to insulin resistance by mechanisms that are unknown. Therefore, RA is considered as an insulin resistance model related with a chronic inflammatory state, where diabetes and obesity, classical factors for IR, are absent. The objective of this study is to estimate RBP4 expression in RA patients.
Methods 101 RA patients and 115 age and sex-matched controls were included. Pancreatic beta cell function was estimated by classical insulinresistance indexes like HOMA (homeostatic model assessment 2). RBP4, C peptide and insuline levels were measured in patients and controls by a specific enzyme-linked immunosorbent assay (ELISA). Multivariate analysis was performed to compare results between patients and controls and the data were adjusted for glucocorticoids intake and for IR classical risk factors.
Results RBP4 levels did not show differences between controls and patients, after adjusting for sex, age, body mass index (BMI) and waist circumference (lnRBP4 2,83 mcg/dl in patients vs. 2,70 mcg/dl, p=0,33). On going steroids patients showed higher RBP4 levels (lnRBP4 3,03 vs 2,61 mcg/dl, p=0.00), after adjusting for age, sex, BMI and waist circumference. Similarly, in the univariate analysis, RBP4 levels tended to correlate with steroid average dose (r=0,20, p=0,14). In our serie, RBP4 levels were not related with the classical IR characteristics, like abdominal waist and BMI, both in controls and patients. Nor these levels showed relation with ESR, CRP, insuline levels or disease activity indexes.
Conclusions The molecular mechanisms that lead to IR in RA patients appear to be different from those that ocurr in obesity and diabetes status. RBP4 does not seem to play a role in IR in patients with RA.
Disclosure of Interest None Declared