Abstract
Purpose:
Diabetic retinopathy (DR) is a multifactorial progressive disease of the retina, involving many different cells, molecules, and factors. Hyperglicemia, hyperlipidemia, dysregulated hormones levels and growth factors induce a cascade of biochemical and physiological changes leading to the neurovascular damage in the retina through oxidative stress, inflammation and apoptosis. The aim of our study was to evaluate whether plasma Homocysteine (Hcy) levels in diabetic patients with and without retinopathy represent a risk factor in the diabetic retinopathy and a therapeutic target.
Methods:
We enrolled 175 diabetic consecutive patients (81 females, 84 males; mean age 65.2 ± 11.8 years, mean duration of diabetes 7.6 ± 5.4 years). The control group was 80 randomly selected healthy subjects under 65 years of age (42 males and 38 females) aged 24 - 64 years (mean 44.6 ± 10.5 years) composed of blood donors and randomly selected volunteers working at the University of Catania; the second control group was composed by 75 randomly - selected patients (34 males and 40 females) ages 30 - 85 years (mean age 60 ± 9.2 years) 50% of whom were institutionalized in Catania. Following on from this study, further work was performed in vitro to test toxicity effects of Hcy in retinal cells.
Results:
The values of sensitivity for both Proliferative Diabetic Retinopathy and Non-Proliferative Diabetic Retinopathy groups were 64% and 63% respectively, and a specificity of 70% for both groups. Predictive value of positive test were 69% vs 54%, Predictive value of negative test 65% vs 50%, Efficiency of the test 67% vs 51%. The odds ratio values were respectively 4.24 vs 1.16. In vitro findings correlated with Hcy associated-toxicity.
Conclusions:
In our study higher plasma levels of homocysteine have been found in diabetic with proliferative diabetic retinopathy compared to both those non proliferative DR and diabetics without retinopathy. Previous studies show that Hcy binds NMDA receptor and leads to oxidative stress, cytoplasmatic calcium influx, cellular apoptosis, and endothelial dysfunction. Therefore the management of homocysteine plasma levels can be a pharmacological target.
Keywords: 499 diabetic retinopathy •
464 clinical (human) or epidemiologic studies: risk factor assessment •
700 retinal neovascularization