Targeting antioxidant strategies for non-proliferative diabetic retinopathy

Abstract

Purpose : Overproduction of reactive oxygen species (ROS) and activation of ROS signalling pathways cause damage to the eyes. We studied the oxidative stress (OS) markers and the effects of a daily, core nutritional supplement regimen containing antioxidants and omega 3 fatty acids (A/ω3), in type 2 diabetic (T2DM) eyes.

Methods : A case-control study was carried out in 480 participants, classified into: 1) T2DM patients (n=287) with (+)/without (−) non proliferative diabetic retinopathy (NPDR) and controls (CG; n=194). Participants were randomly assigned to one A/ω3 daily pill. Evaluation through 38 months permitted to outline patient characteristics, NPDR features, and blood classic and emergent parameters, including OS by products and candidate genes. Statistics were performed by the SPSS 24.0 program.

Results : Significantly higher circulating pro-oxidants (p=0.001) and lower antioxidants (p= 0.0001) were detected in the T2DM patients versus the CG. Significantly higher plasma malondialdehyde/thiobarbituric acid reactive substances (MDA/TBARS; p=0.006) and lower antioxidant load, as from the plasma total antioxidant capacity (TAC; p=0.042) and vitamins B₁₂ (p=0.05) and C (p=0.020) levels, were detected in the T2DM+NPDR versus the T2DM-NPDR. Vitamin C is a cofactor for enzymes involved in collagen synthesis. Overexpression of matrix metalloproteinase-9 (MMP-9) gene (a secreted type IV collagenase involved in extracellular matrix remodelling and cell migration) was found in the T2DM+NPDR versus the T2DM-NPDR groups and the CG (p=0.021). Importantly, the A/ω3 regime significantly reduced the pro-oxidants (p<0.05) and increased the antioxidants (p<0.05) in all groups, with special benefit for the diabetic retina.

Conclusions : This follow-up study reinforces the need for new strategies to increase the antioxidant load, as in the case of A/ω3 supplement regimen, that may serve as dietary prophylaxis and adjunctive intervention for better eye care in patients at risk of diabetic blindness.

This is a 2021 ARVO Annual Meeting abstract.