Retinol binding protein-4 : a driver of cardiometabolic risk in type 2 diabetes mellitus

Abstract EN

The current pandemic of type 2 diabetes is closely associated with obesity and insulin resistance.

It is therefore essential that we gain a greater understanding of the pathogenesis of these two conditions and develop new approaches for their prevention and treatment.

Retinol binding protein-4 (RBP-4) was reported in (2005) by Yang et al., as an adipokine that impair insulin sensitivity. The aim of the current study was to determine the association of visceral adiposity and circulating RBP-4 level in subjects with and without type 2 diabetes and to investigate the association between RBP-4 and various markers related to insulin resistane and diabetic complications. This study was conducted on 48 patients with type 2 diabetes mellitus (Group I), they were 30 males and 18 females with age ranged from 45–60 years.

They were divided into 2 subgroups according to the absence (Group Ia, n=33) or presence (Group Ib, n=15) of microvascular diabetic complications (neuropathy, nephropathy and retinopathy).

Twenty age and sex-matched healthy subjects were also included as a control group (Group II), they were 12 males and 8 females. All studied subjects underwent anthropometric measures, body mass index (BMI), waist circumference (WC), visceral fat area (VFA) by CT abdomen at L4-L5, in addition to various markers of insulin resistance including RBP-4, adiponectin, homeostasis model assessment of insulin resistance (HOMA-IR). Our results showed that RBP-4 level was significantly higher in patients with type 2 diabetes (Group I) than in the control group (Group II) (P<0.05).

Also, it was significantly higher in the group of patients with microvascular complications (Group Ib) when compared to the uncomplicated group (Group Ia) (P<0.001). In our results we could find that RBP-4 was positively correlated with HOMA-IR (r= 0.61, P<0.05), triglyceride (r= 0.52, P<0.05), hsCRP (r= 0.57, P<0.05) and negatively correlated with adiponectin (r= -0.56, P<0.05) and HDL-C (r= -0.61, P<0.05) in the diabetic group.

RBP-4 was found to be positively correlated with BMI (r= 0.48 & 0.46, P<0.05), WC (r= 0.59 & 0.57, P<0.05), VFA (r= 0.60 & 0.59, P<0.05) in both group I and group II respectively In conclusion, serum RBP-4 levels is found to be positively correlated with visceral adiposity in subjects with and without type 2 diabetes mellitus and is associated with certain markers related to insulin resistance and diabetic microvascular complications.

Thus, lowering RBP-4 may be a new target for treating insulin resistance and diabetes.