Diverse NF-kappaB expression in epiretinal membranes after human diabetic retinopathy and proliferative vitreoretinopathy.

PURPOSE Formation of epiretinal membranes (ERMs) after proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR) results in progressive deterioration of vision, but its pathogenic mechanisms are still unknown. This study was conducted to examine the role of nuclear factor kappa B (NF-kappaB) in the formation of ERMs after PDR and PVR. METHODS ERM samples were obtained by vitrectomy from 10 patients with PDR (aged 53+/-12 years with 14+/-5 years of diabetes), 20 patients with PVR, and 17 patients with idiopathic ERMs. Ten PVR and 17 idiopathic ERM samples were processed for reverse transcription-polymerase chain reaction (RT-PCR) analysis. In addition, 10 PDR and 10 PVR membranes were processed for immunohistochemical analysis. RESULTS NF-kappaB mRNA expression levels were significantly higher (10 of 10 versus 9 of 17 subjects in idiopathic ERM, p=0.0119) in PVR subjects. Immunohistochemical analysis showed NF-kappaB protein expression in 8 of the 10 PDR samples as well as all 10 PVR samples, and NF-kappaB positive cells were partially double labeled with glial cell markers. Interestingly, NF-kappaB protein was also overlapped with angiogenic factor interleukin-8 (IL-8) in glial cells as well as vascular endothelial cells. CONCLUSIONS These results suggest that NF-kappaB is involved in the formation of both glial and vascular endothelial cell components, and that these two cell types might have functional interactions that lead to the enlargement of intraocular proliferative membranes.