Anti-VEGFs may cause blindness

Long-term use of anti-vascular endothelial growth factor (VEGF) drugs should be treated with caution because endogenous VEGF plays an important role in the maintenance of retina neuronal cells, according to study results published by PLoS ONE on the 3rd November.

Patricia A. D'Amore of Schepens Eye Research Institute, Harvard Medical School, Boston, US and colleagues neutralized VEGF in rodent models, and suppressed expression of VEGF in an in vitro Müller cell line.

At 14 days of follow-up, in the rodent portion of the experiment, cell apoptosis in the inner and outer nuclear layers was significantly increased, although retinal vasculature remained intact; at week four, however, both the inner and outer nuclear layers had thinned and retinal function had decreased. The in vitro cell line demonstrated that VEGF has an autocrine role in MŸller cell survival. When exogenous VEGF was added to photoreceptor cells and the outer nuclear layers, it demonstrated a highly neuroprotective function. Both photoreceptors and Müller cells were found to express VEGFR2, a VEGF signalling receptor.

The team concluded that VEGF is necessary for the maintenance and function of retinal cells. Therefore, despite their efficacy in reducing oedema and neovascularization in age-related macular degeneration (AMD) patients, chronic use of anti-VEGF treatments should be treated with caution. Dr D'Amore now plans to continue her investigation of the role of VEGF in the eye.