Aims/hypothesis: Formation of epiretinal membranes (ERMs) in the posterior fundus results in progressive deterioration of vision. ERMs have been associated with numerous clinical conditions including proliferative diabetic retinopathy (PDR), but its pathogenic mechanisms are still unknown. This study was conducted to examine whether or not nuclear factor kappa B (NF-kappaB), a transcription factor that can be activated by various pathological conditions, is involved in the formation of ERMs after PDR.
Methods: ERM samples were obtained by vitrectomy from 22 cases with PDR aged 56+/-11 years with 18+/-10 years of diabetes and 15 cases with idiopathic ERM. They were processed for reverse transcription-polymerase chain reaction (RT-PCR) analysis. In addition, 5 ERM samples from PDR patients aged 51+/-16 years with 15+/-6 years of diabetes were processed for immunohistochemical analysis.
Results: NF-kappaB mRNA expression levels were higher (20 out of 22 cases vs. 9 out of 15 subjects in idiopathic ERM, p<0.05) in PDR subjects. Immunohistochemical analysis showed NF-kappaB protein expression in all the 5 ERMs derived from PDR patients, and that region was partially double-labelled with interleukin-8 (IL-8) and von Willebrand factor (vWF).
Conclusions/interpretation: These results suggest a possibility that NF-kappaB is involved in the formation of ERMs after PDR, especially for the development of vascular endothelial cell component.