P-54: Investigation of Endothelial Nitric Oxide Synthase VNTR (Intron 4 a/b) Polymorphism in Diabetic Patient without Complication
Objective: Recent studies have implicated dysfunctional endothelial nitric oxide syntase(eNOS)as a common pathogenic pathway in diabetic vascular complications.However,functional consequences are still incompletely understood.To determine the role of NO in diabetic complications we examined the association between eNOS gene VNTR polymorphism and diabetic complications. Materials and Methods: Patients with diabetes were diagnosed according to American Diabetes Association Criteria. Diabetic retinopathy (DR) was diagnosed by an expert ophthalmologist based on ophthalmoscopic examination. Diabetic nephropathy (DN) was defined as microalbuminuria of more than 30mg/24 hours in two to three samples with exclusion of other conditions that can cause proteinuria. Diabetic neuropathy (DNU)was defined by symptoms or signs according to Diabetes Control and Complication Trial criteria.Patients with neuropathic foot ulcers were defined as neuropathy.The study group comprised of type 2 diabetes patients without complications (n=72) who were recruited from diabetes clinic in the Aliebn Abitaleb hospital, Rafsanjan University, South-east of Iran. Normal healthy controls (n=96) and patient with DNU (n=146) were recruited from the same area.All the subjects selected for this study were from Fars origin. DNA was extracted from WBCs,using salting-out method. PCR was performed to determine allele and genotype frequencies for eNOS gene VNTR polymorphism. Results: We found that both genotype and allele frequencies were significantly different between patients who were complication free (CF) compared to the controls [aa+ab vs bb p=0.007,OR=2.6 95%CI (1.2-5.8) and p=0.001, OR=2.8 95% CI (1.4-5.9)] respectively.Both genotype and allele frequencies were increased in CF patients in compared with patients with DNU, but the difference wasnot significant. Conclusion: We found a significant difference in distribution of eNOS polymorphic variants at both allele and genotype frequencies level in CF patients compared with healthy controls which might be partly due to small sample size studied or might imply the diverse effect of a allele on predisposing to the development of diabetes and its complications so, Further studies on larger number of samples and on different population are required to confirm the results we observed in this study.