Abstract
Purpose:
Choroidal neovascularization (CNV) is a commonly occuring pathology in various eye diseases, e.g. in an advanced stage of age-related macular degeneration (AMD). Vascular endothelial growth factor (VEGF) is known to be upregulated and leads to enhanced endothelial cell growth. The polyphenols resveratrol, epigallocatechine gallate (EGCG) and curcumin have antiproliferative and antiinflammatory effects. In this study, the effects of these polyphenols on human retinal endothelial cells (hREC) were investigated in a cell culture model.
Methods:
hREC were cultured in 2% serum-containing cell culture medium and different concentrations of resveratrol, EGCG and curcumin were tested. Flow-cytometric analysis was performed after 24, 48 and 72 hours of incubation. Absolute cell numbers were counted, cell proliferation was measured with the Carboxyfluorescein succinimidyl ester (CFSE) dilution assay and dead cells were analysed with the nuclear dye Hoechst 33258. Apoptotic cells could be distinguished with active caspase 3 staining.
Results:
All three polyphenols diminished absolute cell numbers and the number of cell cycles in a dose-dependent manner compared to the untreated control. 25 µM Resveratrol led to a significant reduction in cell cycle numbers over 48 hours of nearly 40%. EGCG also had a strong effect on the proliferation and 25 µM reduced the accomplished cell cycles to 0,65 (control: 0,78), with 50 µM the effect was even stronger. Curcumin showed effects already with 5 µM and these effects were enhanced with 10 µM. Only EGCG with a concentration of 25 µM and higher slightly induced cell death, resveratrol even significantly reduced apoptosis of hREC.
Conclusions:
All three polyphenols reduced the absolute number of hREC and had an inhibitory effect on the cell proliferation by reducing the number of cell cycles in a dose-dependent manner. In comparison to previously published data on retinal pigment epithelial cells (Alex et al., 2010) the concentrations were lower to achieve these effects on hREC. In vivo, a cell specific targeting might therefore be achieved by dosing. Further studies are needed to evaluate effects on other retinal cells.
Keywords: 453 choroid: neovascularization •
503 drug toxicity/drug effects •
529 flow cytometry