Platelet-derived growth factor plays a key role in proliferative vitreoretinopathy

Purpose. The action of growth factors is thought to make a substantial contribution to the events leading to proliferative vitreoretinopathy (PVR). In this study, the importance of platelet-derived growth factor (PDGF) was tested in a rabbit model of PVR. Methods. The approach was to compare the extent of PVR induced by cells that do or do not express the receptors for PDGF and therefore differ in their ability to respond to PDGF. Results. Mouse embryo fibroblasts derived from PDGF receptor knock-out embryos that do not express either of the two PDGF receptors induced PVR poorly when injected into the eyes of rabbits that had previously undergone gas vitrectomy. Re- expression of the PDGF β receptor in these cells did not improve the ability of the cells to cause PVR. In contrast, injection of cells expressing the PDGF α receptor resulted in stage 3 or higher PVR in 8 of 10 animals. Conclusions. These findings show that PDGF makes an important contribution to the development of PVR in this animal model. Furthermore, there is a marked difference between the two receptors for PDGF, and it is the PDGF α receptor that is capable of driving events that lead to PVR.