Studies On The Relationship Between Hepatocyte Growth Factor And Proliferative Vitreoretinopathy

Objective:To investigate the relationship between hepatocyte growth factor (HGF) and retinal detachment (RD) with or without proliferative vitreoretinopathy (PVR), further to study the effects of HGF on the morphology, proliferation and wound healing of human retinal pigment epithelium (RPE) cells and try to explain the mechanism of HGF and PVR. Methods:We collected serum and vitreous fluid and epiretinal membranes (ERM) from patients with RD and/or not PVR, the concentrations of HGF were detected by enzyme-linked immunosorbent assay (ELISA), the ultrastructures of ERM were observed by transmission electron microscope (TEM) and HGFR/c-Met expressions by immunohistochemistry (IH). Human RPE cells were cultured in vitro. When co-incubated with HGF, the cell morphological changes and wound healing of cell damage were observed by phase-contrast microscope and cell proliferation assay by MTT. The expressions of cytokeratin (CK), vimentin, fibroblast specific protein (Fsp-1), HGF and HGFR/c-Met were detected by IH. Western blot was used to study the protein expressions of Fsp-1, CK and E-cadherin, and reverse transcriptase polymerase chain reaction (RT-PCR) for mRNA levels. The junction integrity of RPE monolayer were assessed by TEM and scanning electron microscopy (SEM). Results:The mean HGF concentration in serum of RD and PVR patients was lower than that in intraocular fluid, there was no relationship. With the development of PVR, vitreous concentrations of HGF significantly increased, but there was no different between the degree C and D. In ERM, the dominant distribution was epithelial and fibroblastoid cells combined with large number of collagen fibril, and HGFR/c-Met was expressed most in cells with pigment granules. In cultured RPE cells, the expressions of CK, vimentin, Fsp-1, HGF and HGFR/c-Met were positive. By thestimulation of HGF, we observed that the morphology of RPE cells was changed into elongated spindle shapes characteristics of fibroblasts, which led to the expressions of E-cadherin and CK lost in protein and gene levels, while the expressions of Fsp~l and TGF-B2 increased. At the same time, HGF made the junction integrity of RPE monolayer disrupt and the migration and proliferation increased. Conclusions:HGF may be an auto-secreted factor of human RPE cells. Concentrations of HGF increase in PVR. HGF can break the junction integrity of RPE monolayer, lead to an epithelial-to-mesenchymal shape change and stimulate RPE cells migration and proliferation. Those findings are consistent with the hypothesis that HGF may play a role in the RPE mesenchymal transformation that typifies PVR.