Lipid peroxidation in proliferative vitreoretinopathies

Purpose To study the lipid hydroperoxide activity in vasoproliferative and fibroproliferative retinal disorders. Methods Vitreous body samples from patients undergoing vitrectomy because o f proliferative vitreoretinopathy (PVR; n = 12) or proliferative diabetic r etinopathy (PDR; n = 15), and rhegmatogenous retinal detachment/macular hol e/epiretinal membranes as the comparison group (CG; n = 14), were analysed for protein content and basal and induced lipid peroxidation (LPO), as dete rmined by the thiobarbituric acid reactive substances (TBARS) test and LPO 586 commercial kit. The antioxidant activity for superoxide dismutase (SOD) and catalase (CAT) was also assayed. Results Malondialdehyde (MDA)-like metabolites and 4-hydroxynonenal (4-HNE) mean values were first measured to assess basal LPO, and found to be signi ficantly higher in the PVR and PDR cases than in the CG (p less than or equ al to 0.0001). LPO induced by nicotine adenine dinucleotide phosphate iron (NADPH-Fe) was then assayed and the data showed that MDA mean values were 5 -fold greater for the PVR and PDR eyes than in the case of basal LPO (p les s than or equal to 0.0001). SOD activity was significantly smaller in the P VR (p = 0.0010) and PDR (p less than or equal to 0.0001) groups than in the CG. CAT levels displayed significantly lower values in the PVR and PDR cas es than in the CG (p less than or equal to 0.0001). No significant differen ces in free radical (FR) formation and antioxidant status between PVR and P DR patients were observed. Conclusions Fibrovascular proliferative vitreoretinopathies correlate with increased FR formation and decreased antioxidant activity in the human vitr eous body.