Effects of trace elements on albumin and lipoprotein glycation in diabetic retinopathy

Objectives: To test the effect of some trace elements, on protein and lipoprotein glycosylation and their impact on the severity of diabetic retinopathy. Methods: A case control study was conducted in 42 diabetic patients (14 without retinopathy [DC]; 14 with non-proliferative diabetic retinopathy [NPDR]; 14 with proliferative diabetic retinopathy [PDR]) at Ebin Al-Haitham Specialized Hospital, Baghdad, Iraq for Ocular Diseases from February to December 2008. In addition to 20 age and gender matched healthy controls (NC). The glycation of albumin, alpha-, pre beta-, and beta-lipoproteins was measured by agarose gel electrophoresis. Serum levels of cadmium (Cd), selenium (Se), chromium (Cr), zinc (Zn), and copper (Cu) were analyzed by flameless atomic absorption spectrophotometer. Results: There was significant elevation in the mean serum glycated beta-lipoprotein in DC (p 0.05) and a near significant increase (p=0.06) in the means of both glycated albumin and pre beta-lipoproteins among the PDR and NPDR groups. Moreover, a significant reductions in serum means of Cd (p 0.05) and Zn/Cu ratios (p 0.001) were recorded in all diabetic retinopaths as compared to DC. The Cd level rises with the increase in duration of diabetes (p 0.001) and hyperglycemia (p 0.025) whereas, the serum Cr values decreases with the progression of diabetes (p 0.025). Conclusion: Both glycation and oxidative processes are involved in the development of diabetic retinopathy, and changes in the concentration of Cd, Se, Cr, Zn, and Cu have some impact on the disease progression.