CANDIDATE GENE ANALYSIS IN DIABETIC RETINOPATHY: IGF-I GENE

The alteration of IGF-I systemic level in diabetes is typically characterized by depletion of free IGF-I plasma level and its decreased bioavailability. With regard to protective and advantageous effects of IGF-I on tissue healing and cellular regeneration such depletion could facilitate or accelerate tissue damages and complications. By contrast, the local concentration of IGF-I is reportedly increased in particular tissues during some occasions, which has also clinical implications as IGF-I could function in an autocrine and paracrine manner.The present study was conducted to assess that whether the differential outcome of diabetic subjects relative to diabetic retinopathy (DR) is linked to some extent to the structural variations of IGF-I gene. Two polymorphisms of the IGF-I gene at positions -383*C/T and -1089*C/T were employed for genotyping analysis by ARMS-PCR assay and the data of genotype/allele distribution was compared between two subgroups of 248 British Caucasian type 1 diabetic subjects, 135 cases with DR and 113 controls (DR-). The distribution of these polymorphisms did not associate significantly with presence or absence of DR (P≥ 0.05). Since the involvement of IGF-I in development of DR is fairly rational, our results firstly may reflect some reservations about the functionality of the employed polymorphic markers and secondly may indicate that all regulators of IGF-I functionality or its local concentration level including IGFBPs and IGFRs should be taken into account, so their genes could be the subject of new study to accomplish current investigation. Keywords: