Retinal pigment epithelial cells release a chemoattractant for astrocytes
S. L. Rowen and B. M. Glaser
Astrocyte migration was studied using a modified Boyden chamber. Astrocytes
migrated in response to a concentration gradient (chemotaxis) of retinal
pigment epithelial cell-conditioned medium. In contrast, smooth muscle
cell- and corneal fibroblast-conditioned media stimulated random migration
(chemokinesis) of astrocytes but not chemotaxis. Furthermore, retinal
pigment epithelial cell-conditioned medium stimulates only random migration
of smooth muscle cells and corneal fibroblasts. The chemotactic factor
produced by retinal pigment epithelial cells appears to have a molecular
weight between 10,000 and 30,000 determined by ultrafiltration. Activity is
lost after boiling but is stable, with a pH between 2 and 7. These results
suggest that in proliferative vitreoretinopathy, retinal pigment epithelial
cells on the retina and within the vitreous cavity may release a
chemoattractant that stimulates astrocytes to migrate into the vitreous
cavity.
