The retinal pigment epithelium (RPE) is a monolayer of polarized cells that constitutes a barrier between photoreceptor cells of the neural retina and the choroidal blood capillaries, the so-called blood-retinal barrier. These cells play a critical role in the maintenance of retinal homeostasis and visual function. Therefore, damage in this cellular layer may cause several pathologies such as age-related macular degeneration (AMD). In AMD, the damage in the RPE cells leads to photoreceptor degeneration, causing a partial or total vision loss. The molecular mechanisms involved in the early stages of the disease are still unknown, but the available studies suggest that RPE cells may undergo an epithelial-mesenchymal transition triggered by the pathological environment; thus, promoting the progression of the disease. To test this hypothesis, in the present study we have performed a protein analysis of human retinal pigment epithelial cell cultures, treated with serum from patients with AMD. The protein markers used in the analysis were first tested, classified and selected by using them to characterize the developmental process of the epithelial cell culture at 7, 14 and 21 days. The results achieved in this study are consistent with the suggested phenotypic change, but they should be considered as preliminary data that must be complemented with additional experiments.
