Thalidomide and prednisolone inhibit growth factor-induced human retinal pigment epithelium cell proliferation in vitro.

Thalidomide and prednisolone were recently introduced as treatment modalities in age-related macular degeneration (AMD). Growth factor-induced activation of retinal pigment epithelial (RPE) cells is a crucial event in this disease. The purpose was to examine the effect of thalidomide and prednisolone on growth factor-preactivated RPE cells. Human RPE cells were stimulated with 10 ng/ml platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF), or vascular endothelial growth factor (VEGF) for 24 h. Afterwards, thalidomide (50 microg/ml) or prednisolone (100 ng/ml) were added for 24 h. RPE cell proliferation was determined by [3H]-thymidine incorporation. PDGF and bFGF significantly stimulated human RPE cell proliferation (p < 0.005), the value for VEGF stimulation was not significant (p = 0.3). The effect of the growth factors was diminished after addition of thalidomide and prednisolone (p < 0.005). The current study shows that the inhibitory properties of thalidomide and prednisolone remain even after growth factor activation of the cells. Copyright 2001 S. Karger AG, Basel