Direct comparison of the migration of three cell types involved in epiretinal membrane formation.

PURPOSE: The purpose of the present study was to develop an accurate and sensitive migration assay to compare the migratory capabilities of retinal pigment epithelial (RPE) cells, retinal glial (RG) cells, and fibroblasts (the cell types crucial in epiretinal membrane [ERM] formation) under identical microenvironmental conditions and thus to identify potential target areas in ERM management.
METHODS: Cultured bovine RPE and RG cells and scleral fibroblasts (SFs) in both single and mixed cell type populations were induced to migrate in modified 48-well Boyden chambers. The labels used to distinguish between the cell types were latex microspheres and carmine particles. The chemoattractants used were fibronectin and PDGF, both of which are associated with epiretinal membrane development.
RESULTS: When migrating independently, all three cell types showed a positive response to fibronectin at an optimal concentration of 10 microg/mL. The RG cells migrated in a significantly greater number than the RPE cells (P < 0.05), but the differences in number of migrating cells between RG cells and SFs and RPE cells and SFs were not significant. When the cells were labeled and migrating together, it became clear that the RG cells consistently migrated in a higher number than the SFs (P <or= 0.001) and both the SFs and RG cells showed a greater migratory response than the RPE cells (P <or= 0.01).
CONCLUSIONS: The mixed cell migration (MCM) test system is a simple and useful assay to distinguish between the migratory responses of different cell types in the same microenvironment. It has highlighted the pronounced migratory response of RG cells to standard chemoattractants and has cast some level of doubt that, in comparative migratory terms, RPE cells are particularly good responders.