Mitochondrial Membrane Potential Response of Retinal Pigment Epithelium Cells In Vitro to Anti-VEGF Agents: Ranibizumab, Bevacizumab, Aflibercept and Ziv-aflibercept

Abstract

 

Purpose

 

Vascular endothelial growth factor (VEGF) plays an important role in normal retinal function and in maintenance of the choriocapillaris by the retinal pigment epithelium (RPE). Chronic use of anti-VEGF agents to treat wet age-related macular degeneration (AMD), while of obvious net benefit to patients, may also lead to progression of geographic atrophy and dry AMD in treated eyes. Experimental studies have shown the presence of VEGF-blockade toxicity in retinal ganglion cells, photoreceptors and choriocapillaris in mouse models. The aim of this study was to compare the effects of anti-VEGF drugs on mitochondrial membrane potential of RPE cells in culture in order to determine if these drugs have measurable and differing safety profiles.

 

Methods

 

Human RPE cells (ARPE-19) were exposed for 24 hours to one of the four anti-VEGF drugs at 1/2X, 1X, 2X or 10X clinical concentrations (X= drug dose per 4 ml of culture media: ranibizumab, 0.5mg; bevacizumab, 1.25mg; aflibercept, 2mg; ziv-aflibercept, 2mg). Mitochondrial membrane potential assay using JC-1 dye was performed to evaluate early apoptotic changes as a marker of cell damage rather than frank cell death.

 

Results

 

Mitochondrial membrane potential was not significantly decreased at one half the clinical dose (1/2X) for any of the four drugs tested. Similarly, for ranibizumab and aflibercept, cells exposed to 1X clinical dose revealed no significant change in mitochondrial potential. However, bevacizumab and ziv-aflibercept at the 1X clinical dose showed a significant reduction in mitochondrial membrane potential. At supranormal doses, only ranabizumab at the 2X clinical dose did not show a reduction in mitochondrial membrane potential. At 10X clinical dose all four drugs showed significant reductions in mitochondrial membrane potential. (Figure.1)

 

Conclusions

 

At clinical dose (1X), neither ranibizumab nor aflibercept produced evidence of mitochondrial toxicity. However, both bevacizumab and ziv-aflibercept showed mild mitochondrial toxicity at clinically equivalent doses. At supranormal doses, only ranibizumab at twice the clinical dose showed no significant evidence of mitochondrial toxicity.

 

 

Figure 1. Mitochondrial Membrane Potential of ARPE-19 cells after treatment with Ranibizumab, Bevacizumab, Aflibercept and Ziv-aflibecept. (ns-not significant)

 

Keywords: 412 age-related macular degeneration • 701 retinal pigment epithelium • 748 vascular endothelial growth factor