Homocysteine induces oxidative stress in young adult central retinal vein occlusion

Objectives High levels of plasma homocysteine have been reported to be toxic to the vascular endothelium, thereby creating an environment of hypercoagulability and occlusion. Elevated homocysteine has been reported as a risk factor for young adult central retinal vein occlusion (CRVO) cases. This study aimed to see if oxidative stress is an independent risk factor or is homocysteine dependent.

Methods 23 young adult CRVO patients and 54 age and sex-matched controls were included in the study. Oxidative stress markers thiobarbituric acid-reacting substance (TBARS), superoxide dismutase (SOD), total thiols, glutathione peroxidase and total antioxidant capacity (TAC) were estimated. The effect of homocysteine (25–200 μM) on cultured bovine retinal endothelial cells (BREC) on oxidative stress parameter TBARS was measured.

Results There was a significant increase in the plasma TBARS in CRVO cases compared with controls (p=0.000). SOD and TAC were significantly lower in CRVO cases than controls (p=0.000, p=0.022). There was a significant negative correlation between TAC and TBARS (p=0.00) and a significant positive correlation between homocysteine and TBARS (p=0.029). Nominal regression analysis showed that TAC and homocysteine influence TBARS significantly. The in-vitro study in BREC cells revealed that homocysteine increased the TBARS dose and time dependently.

Conclusion TBARS and homocysteine are known to be independent risk factors for CRVO. TBARS can be influenced by both homocysteine and TAC, thereby contributing to the aetiopathology of CRVO by increasing oxidative stress.