Abstract

Purpose. To describe new details of epiretinal cell proliferation in flat-mounted internal limiting membrane (ILM) specimens. Methods. One hundred and nineteen ILM specimens were removed en-bloc with epiretinal membranes (ERMs) from 79 eyes with macular pucker (MP) and 40 eyes with vitreomacular traction syndrome (VMTS). Intraoperatively, posterior vitreous detachment (PVD) was assessed as complete or incomplete. Whole specimens were flat-mounted on glass slides, and processed for interference and phase contrast microscopy, cell viability assay, and immunocytochemistry. Results. Mean cell viability percentage was higher in MP than in VMTS. Two cell distribution patterns were found. Anti-CD163 labeling presented predominantly in MP with complete PVD. CD45 expression was similar in all groups of diagnosis. Anti-GFAP labeling was found in MP irrespective of the extent of PVD. Alpha-SMA labeling mainly presented in MP with incomplete PVD and in VMTS. Simultaneous antibody labeling included GFAP/CD45, GFAP/CD163, CD163/CD45, and CD163/α-SMA. Conclusions. Hyalocytes constitute a major cell type of epiretinal cell proliferation in eyes with MP and VMTS. Glial cells, notably retinal Müller cells, are involved as well. It appears that transdifferentiation of cells in vitreomacular traction might be more frequent than previously thought and that those cells possess even more different immunocytochemical properties than expected.