Role of Bilirubin in the Development and Progression of Diabetes Mellitus Type (2) and its Complications

Diabetes mellitus (DM) is defined as a metabolic disorder that is characterized by hyperglycemia and disturbance in the metabolism of macro-molecules. Complications of DM include micro-vascular diabetic complications such as nephropathy and retinopathy. Bilirubin is a waste toxic product, however, its role as an endogenous anti-oxidant was studied. The study aims to investigate the role of bilirubin in the progression of nephropathy and retinopathy in type (2) diabetes patients. This was conducted on 4 groups, healthy controls, diabetics without complications, diabetics with retinopathy and diabetics with nephropathy. Laboratory investigations were performed for participants including; urine albumin/creatinine ratio, glycosylated hemoglobin (HBA1C), serum total and direct bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, cholesterol, triglycerides, high-density lipoprotein –cholesterol (HDL) and fasting blood glucose (FBG). There was a significant increase in serum total bilirubin, direct bilirubin, ALT, AST, urea, creatinine, total cholesterol and HBA1C between the control group and all groups of patients. Also, there was a significant difference in urine albumin /creatinine ratio in all groups of patients compared to controls. Serum direct bilirubin was significantly higher in the diabetic nephropathy group when compared to the diabetics without complications and retinopathy groups. Serum total bilirubin was lower in diabetics with retinopathy when compared to diabetics without complications. These results mean that increased serum level of both direct and total bilirubin has a protective effect in diabetic nephropathy and retinopathy.