١ The Relationship of Plasma Visfatin and Retinol Binding Protein - 4 to Fat Composition - assessed

Background and objectives: Adipose tissue is responsible for releasing various adipokines which have been related to insulin resistance. Understanding the relationship of these adipokines to insulin resistance may help in early diagnosis and faster the development of new treatments for diabetes. The objective of this study was to determine the possible association between these adipokines (visfatin and retinol-binding protein-4 (RBP-4)) in type 2 diabetes and obesity. The role of ultrasound measurements was to determine which of the adipose tissue most closely relates to visfatin and RBP-4 levels. The subcutaneous fat or the visceral fat. Participants and Research Design: According to the body mass index (BMI), 40 type 2 diabetes patients were divided into two equal groups, the 1 st was non-obese diabetic patients with BMI < 25 Kg/ m 2 and the other was obese diabetic patients with BMI >25 Kg/m 2 . There were 40 healthy persons in the control group; also, divided into two equal groups according to the BMI. Anthropometric and biochemical measurements were done by using standardized techniques. Fasting plasma visfatin, RBP-4 and insulin levels were measured by enzyme-linked immunosorbent assay. Insulin resistance index was calculated by the homeostasis model assessment (HOMAIR). Visceral fat in multiple sites, subcutaneous fat were measured by Ultrasonography in addition to assessment of presence or absence of fat deposition in the liver. Results: The levels of plasma visfatin were increased significantly in diabetics compared to control group; moreover, visfatin concentration in diabetics obese was significantly higher compared to diabetics non obese. It was also highly related to the amount of visceral fat but not with subcutaneous fat. The levels of plasma RBP-4 were significantly higher in obese patients compared to control group. Furthermore, the levels of RBP4 were significantly higher in diabetics in comparison to non-diabetics with similar BMI values. Plasma visfatin was positively correlated with RBP-4, BMI, waist / hip ratio (WHR), insulin, insulin resistance index and visceral fat area in diabetic patients, while it was negatively correlated with systolic blood pressure. On the other hand, plasma RBP-4 correlated positively with visfatin, BMI, WHR, blood glucose, insulin and insulin resistance index, and fatty liver detected by ultrasound in diabetic patients. RBP-4 was not related to either visceral or subcutaneous fat. Stepwise regression analysis revealed that plasma visfatin levels remained positively associated with visceral fat and WHR; while plasma RBP4 levels remained positively correlated with BMI, fatty liver in diabetic patients. Conclusion: Plasma visfatin levels are significantly higher in diabetics than control subjects and positively correlated with visceral fat but not with subcutaneous fat.