Expression of growth, trophic and inflammation factors in epiretinal membranes in patients with severe proliferative vitreoretinopathy

Proliferative vitreoretinopathy (PVR) is an ocular pathology caused by an eye inflammation, complicating the course of rhegmatogenous retinal detachment. Cell proliferation on the surface of the retina and epiretinal membrane formation are stimulated by growth factors and inflammatory mediators. Cyclooxygenase (COX) catalyzes the production of prostaglandins from arachidonic acid, that is one of the mechanisms of initiation and maintenance of the inflammatory reaction. Nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) ensure the viability of neurons and glial cells in the retina. Vascular endothelial growth factor (VEGF) has angiogenic, neuroprotective, anti-apoptotic effects on the retina. Here, Tikhonovich et al examine the expression level of COX-1 and COX-2, neurotrophins BDNF and NGF, VEGF in epiretinal membranes from patients with a severe proliferative vitreoretinopathy. Moreover, their study findings suggest that the presence of membrane, formed under the PVR condition, promotes maintenance of inflammation in the eye and stimulates its own growth. One one side, the membrane performs neuroprotective function by secreting growth factors that preserve the viability of retinal ganglion cells which are situated directly under the fibrous tissue, on the other--the production of these factors ensures the viability, growth and development of membrane cells. For the first time it is found that COX-1, COX- 2, BDNF and VEGF are expressed in the membranes, formed as a result of rhegmatogenous retinal detachment complicated by PVR. NGF synthesis is observed in 30% of cases. Correlations in expression of COX-1, VEGF and BDNF are observed in epiretinal membranes formed in the course of PVR.