Evaluation of serum irisin, retinol-binding protein-4 in human obesity

Retinol-binding protein 4(RBP4), and irisin originally described as an adipocyte-specific hormone, has been suggested to be an important link between obesity, insulin resistance and diabetes. To test the hypothesis that irisin and RBP4, and insulin concentrations will be higher in obese subject than in normal weight. A total of 176 individuals were evaluated, which divided into three groups according to BMI. Group I (Normal Weight group n=75), Group II (Over Weight group, n=50), Group III (Obese group, n=51). Serum irisin RBP4and insulin levels were evaluated by enzyme-linked immunosorbent assay. The statistical analysis (students t-test) exhibited significant (P> 0.0001)elevation for Serum RBP4 , Irisin, and insulin in over weight and obese groups compared with normal weight groups{(57.6 ± 16.0), and (70.1 ± 19.9)vs (41.8 ± 13.3) µg/ml ; p< 0.001},{(168.19 ± 11.71) and (171.35 ± 11.81) vs(146.19 ± 9.13) ng/mL: p< 0.05},{(7.25 ± 2.04), and (9.02 ± 4.75) vs (4.91±1.87) mU/mL; p< 0.001} respectively. Linear regression analysis showed significant positive correlations between serum insulin with RBP4 and, Irisin.

Conclusion: In the cross sectional study, obese individuals had significant upregulation of circulating irisin, and RBP4 compared to non-obese subjects.