Abstract
Purpose::
Choroidal neovascularization (CNV) is a main complication that causes severe vision loss in age-related macular degeneration patients. Neovascularization is a complex multistep process including migration and proliferation of vascular endothelial cells. Platelet-activating factor (PAF) is a biologically active phospholipid functioning through activation of a G-protein-coupled receptor. It is one of the most potent proinflammatory factors described. It has also been linked to the angiogenesis in some ocular tissues such as the cornea. PAF stimulates corneal neovascularization in some animal models. PAF also contribute to the angiogenic activity of certain cytokines including vascular endothelial growth factor (VEGF) which plays an important role in the pathogenesis of CNV. It is therefore of importance to study the role of PAF in the pathogenesis of CNV. Our previous study showed that PAF receptors are present in choroidal endothelial cells both in vivo and in vitro. The purpose of this study is to investigate the effect of PAF on the migration and proliferation of choroidal endothelial cells (CE).
Methods::
CE cells were originally isolated from monkey and cultured in Eagle's minimal essential medium at 37º C until the cells reached 80% confluence. Cells were then harvested following trypsinization. Cell migration status and proliferation rate were analyzed in the presence and absence of the exogenous stable derivative of PAF (c-PAF), the PAF receptor antagonist (WEB 2086) and bevacizumab (Avastin), a monoclonal antibody specific against VEGF. The transwell assay was used to study CE cell migration. Colorimetric assay with Thiazolyl Blue Terazolium Bromide as the marker was used to study CE cell proliferation. In addition, Annexin V was utilized as the apoptotic cell marker to study possible apoptotic effect of WEB 2086 and Avastin on the CE cells.
Results::
cPAF stimulated CE cell migration in a concentration-dependent manner and no significant effect on the proliferation of these cells was observed. . The effect of cPAF on CE migration was inhibited by WEB 2086 and Avastin. WEB 2086 and Avastin did not alter apoptotic cell death of CE cells compared to the control.
Conclusions::
PAF may play a role in the pathogenesis of choroidal neovascularization by stimulating choroidal endothelial cell migration.
Keywords: age-related macular degeneration • choroid: neovascularization