K469E polymorphism of the intracellular adhesion molecule 1 gene is associated with proliferative diabetic retinopathy in Caucasians with type 2 diabetes

Background:  In proliferative diabetic retinopathy (PDR) increased levels of cytokines, inflammatory cells and angiogenic factors are present. These factors increase the expression of cellular adhesion molecules (CAMs) The objective of this study was to investigate the association between the polymorphisms of the ICAM-1 gene (K469E, G241A) and the development of PDR among patients with type 2 diabetes in the Slovenian population (Caucasians).
Methods:  For the purpose, 195 subjects with type 2 diabetes with PDR were compared with 143 subjects with type 2 diabetes of duration of more than 10 years who had no clinical signs of diabetic retinopathy. We analysed serum ICAM levels in 54 subjects with type 2 diabetes and 25 subjects without diabetes.
Results:  A significantly higher frequency of the EE genotype of the K469E polymorphism of the ICAM-1 was found in the patients with PDR compared with those without diabetic retinopathy (OR = 2.0, 95% confidence interval [CI] = 1.1–3.5; P  = 0.013), whereas the G241A polymorphism of the ICAM-1 gene failed to yield an association with PDR. Moreover, significantly higher sICAM-1 serum levels were demonstrated in diabetics with the EE genotype compared with those with the other (EK + KK) genotypes (918 ± 104 vs. 664 ± 209 µg/L; P  = 0.001). The G241A polymorphism of the ICAM-1 gene, on the other hand, failed to affect sICAM-1 serum levels in diabetics.
Conclusions:  We may conclude that the EE genotype of the K469E polymorphism of the ICAM-1 might be a risk factor for PDR in the Slovenian population (Caucasians) with type 2 diabetes.