Abstract
Purpose: :
Off-label use of intravitreal bevacizumab, a humanized anti-vascular endothelial growth factor (VEGF) antibody, has been used in a wide spectrum of retinal and retinal vascular diseases. Recent reports have demonstrated penetration of bevacizumab into the outer retina and choroid. The primary aim of this study is to evaluate the in vitro effects of bevacizumab on cell lines representative of different retinal and choroidal cells, namely monkey choroidal endothelial (RF6A), human retinal pigment epithelial (ARPE-19) cells and rat retinal ganglion cells (RGC-5).
Methods: :
RF6A, RGC-5, and ARPE-19 cells were exposed for 24 hours to increasing doses of bevacizumab (0.1, 1.0, 2.0 mg/mL.) Cell numbers were quantified with WST-1 assay and compared with controls. Cell death was assessed using propidum iodide (PI) staining by flow cytometry and fluorescent microscopy. Hydrogen peroxide (1mM) was used as a positive control in cytotoxicity and cell death experiments. VEGF (12.5, 25, 50, 100 ng/mL) induced cell proliferation and the antagonistic effect of bevacizumab was evaluated in parallel experiments by using increasing doses of VEGF (12.5, 25, 50, 100 ng/mL) and neutralizing 50ng/mL VEGF with increasing doses of bevacizumab (0.1, 1.0, 2.0 mg/mL.)
Results: :
Treatment with bevacizumab did not affect the cell viability as compared with control at the doses tested (p>0.25) nor did it increase cell death assessed by flow cytometry. These results were supported by fluorescent microscopy of PI stained cells. VEGF at 50ng/mL induced cell proliferation in all cell lines (p<0.005). Bevacizumab reduced this effect at 1.0 mg/mL in RGC-5 and ARPE-19 cells (p<0.05) and at 2.0 mg/mL in all cell lines (p<0.005)
Conclusions: :
Bevacizumab was not cytotoxic to monkey choroidal endothelial cells, rat retinal ganglion cells, and human RPE cells in vitro at doses effective against VEGF in cell proliferation studies. Further, bevacizumab had no effect on cell viability or cell death at doses 1 log unit above and below those currently used clinically.
Keywords: drug toxicity/drug effects • retinal culture • choroid