98th Annual Meeting DOG 2000

P 9

Effect of Thalidomide and Prednisolonone on the secretion of growth factors by human RPE cells in vitro

M. J. Jakobczyk-Zmija, C. Kaven, J. Kampmeier, C. W. Spraul, G. E. Lang

Purpose: Thalidomide and prednisolone are therapeutic agents that may have beneficial effects on the treatment of proliferative vitreoretinal diseases. The effect of thalidomide and prednisolone on the secretion of PDGF and bFGF by human RPE cells into their cell culture medium was investigated.

Methods: Human RPE cells were confluently seeded into 96-multiwell-plates and allowed to adhere. Afterwards, the culture medium was changed to serumfree medium and the cells were incubated for 48 hr with HAM`s F-10 + 1% BSA plus either thalidomide (50 µg/ml) or prednisolone (100ng/ml). Culture medium without the drugs served as a control. The amount of secreted PDGF and bFGF into the culture medium was determined by ELISA. Assays were performed in duplicate and repeated three times. For statistical evaluation the Student-t-test was used.

Results: Thalidomide showed no significant effect on the secretion of growth factors by human RPE cells. Prednisolone significantly lowered PDGF secretion, but had no effect on bFGF secretion. In the control medium 28.3 pg/ml PDGF and 39.0 pg/ml bFGF were detected, with thalidomide it was 26.0 pg/ml PDGF (p=0.4) and 77.3 pg/ml bFGF (p=0.5). In the prednisolone-containing assays, a concentration of 10.4 pg/ml PDGF (p=0.03) and 31.3 pg/ml bFGF was measured (p=0.1).

Conclusions: The secretion of bFGF by human RPE cells is not influenced neither by thalidomide nor by prednisolone. In contrast, PDGF secretion was reduced by prednisolone, but not by thalidomide. This implicates that prednisolone may alter parts of the endomembrane systems or of the secretory signal sequence of PDGF. Therefore, prednisolone may be an useful agent in blocking autocrine PDGF-loops in RPE cells.

University of Ulm, Department of Ophthalmology, Germany