Tumour necrosis factor α-308 G/a and -238 G/a polymorphisms as predicator of diabetic retinopathy in Egyptians.

Background: Diabetic retinopathy (DR) is a duration dependent serious micro vascular insult of diabetes mellitus. Inflammation has a critical role in the development of early and late stage of DR. Tumour necrosis factor alpha (TNF-α) is an inflammatory cytokine that promoteup regulation of adhesion molecule expression, leukocyte recruitment and monocyte attraction. TNF-α levels are increased in retinas or vitreous of diabetic animals. A cross-sectional, observational study was performed in a sample of diabetic patients who attend diabetes polyclinic of RIO Hospital, Giza, Egypt, between October 2016 and December 2019. Three hundred diabetic patients were studied (150 males and 150 females). 100 diabetic patients without retinopathy, 100 diabetic patients with proliferative retinopathy (PDR), 100diabetic patients with non-proliferative retinopathy (NPDR), also 100 healthy subjects as a control group All patients and subjects were analysed for serum TNF-α levels by ELISA assay and -308 G/A and -238 G/A polymorphism by using Restriction fragment length polymorphisms.

Aim: Evaluating the role of tumour necrosis factor α and -308 G/A, -238 G/A polymorphisms in the pathogenesis of proliferative diabetic retinopathy among Egyptian patients.

Results: A statistically significant increase in TNF-α levels was detected in diabetic without retinopathy, NPDR and PDR groups compared to control group (p > .001). There were no significant different in Genotype and allele frequencies of the -308G/A, and -238 G/A, polymorphisms in both NPDR and PDR. However, the G/G genotype of the -308 G/A polymorphism occurred more frequently in PDR patients with than NPDR patients (0.74% vs 0.68%).

Conclusion: The present study clearly demonstrated increased levels of TNF-α, in diabetic patients with diabetic without retinopathy, NPDR and PDR. Furthermore, this study suggested that TNF-α assay could be used as diagnostic tools to predict the initiation and progression of diabetic retinopathy. They could serve as biomarkers not only for an early detection of the disease, but also to monitor the effects of therapy. Also, the G/G genotype of the -308 G/A polymorphism and the G allele of TNF-α gene were more frequent in PDR patients than with NPDR.