Abstract
Purpose: :
To analyze levels of malondialdehyde (MDA), a marker of membrane lipid peroxidation, and the total antioxidant capacity in the blood, aqueous humor, and vitreous bodies of diabetic and nondiabetic patients. We also assessed the energy charge potential (ECP), a biomarker of tissue energy status, in blood samples.
Methods: :
Nineteen patients with type 2 diabetes mellitus and diabetic retinopathy were examined. Ten were scheduled for cataract surgery and pars plana vitrectomy because of proliferative diabetic retinopathy (PDR). The other nine had mild nonproliferative retinopathy (NPDR). Fourteen nondiabetic, age-matched subjects were enrolled as a control group. These patients and the diabetic patients with NPDR patients were scheduled for cataract surgery and vitrectomy for the removal of epiretinal membranes. Blood, aqueous humor, and vitreous body samples were collected at the time of surgery, and MDA concentrations and blood ECP were measured with high performance liquid chromatography. The total antioxidant capacity of the samples was estimated with the oxygen radical absorbance capacity method.
Results: :
The level of serum and vitreous MDA in PDR group is significantly higher compared to controls and to NPDR patients. PDR patients have also lower levels of total antioxidant capacity at the level of vitreous body and aqueous humor but not at the level of blood plasma as compared with control subjects and with NPDR patients. In blood plasma samples, the ECP value resulted to be significantly lower in all diabetic patients as compared to control subjects.
Conclusions: :
Our study supports the hypothesis that oxidative stress and the decrease of antioxidant defensive mechanism are associated with the progression of diabetic retinopathy to the proliferative form. Anti-oxidants supply may have the potential effects of correcting oxidative stress and may help to inhibit disease progression.
Keywords: oxidation/oxidative or free radical damage • diabetic retinopathy • vitreoretinal surgery