Indicators of oxidative tissue damage and inflammatory activity in epiretinal membranes of proliferative diabetic retinopathy, proliferative vitreoretinopathy and macular pucker.

PURPOSE

To evaluate whether oxidative tissue damage and inflammatory reactions occur in epiretinal membranes of eyes suffering from proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), and macular pucker (MP).

METHODS

Epiretinal membranes were removed during surgery and frozen at -80 degrees C (PDR, n = 26; PVR, n = 24; MP, n = 15), and oxidative tissue damage and inflammatory activity (MPO) of the membrane tissue were determined. The values are expressed as means of thiobarbituric acid-reactive substances (TBARS, nmol/mg) and MPO (units/mg).

RESULTS

Both TBARS and MPO activity were significantly elevated (P < 0.05) in membranes of eyes suffering from PVR and PDR compared to MP. The myeloperoxidase activity in PDR membranes was significantly increased (P < 0.05) compared to PVR.

CONCLUSIONS

Inflammatory cells and oxidative metabolites lead to oxidative reactions in PDR and PVR. The proliferation of membrane tissue may be enhanced through products of the lipoxygenase pathway, which is active in inflammatory cells and leads to oxidative tissue damage. Chemoattraction of leukocytes by oxidative metabolites renders the process self-progagating. Since patients suffering from MP have an intact vitreous body with an intact antioxidative system, this reaction occurs to a lesser degree, resulting in less membrane-growth activity. The cell-growth-enhancing properties of inflammatory cells should be further investigated in PDR and PVR with regard to new therapeutic interventions.