Anti-VEGF drugs for retinal diseases could have serious side effects, scientis...(ritical. She and her laboratory mimicked...),Health

After two weeks, the team found no effect on blood vessels of the inner retina, but did find a significant increase in the number of dying cells of the inner and outer nuclear layers which include amacrine cells that participate in transmitting the visual signal; Muller cells that also participate in the visual signal and support the photoreceptors; and, photoreceptors, which are responsible for color and night vision. The team then used electroretinograms to measure visual function and found a significant loss in visual function. Consistent with these observations, they discovered that both photoreceptors and Muller cells express VEGFR2, the major VEGF signaling receptor and they found that neighboring Muller cells express VEGF.

Parallel studies in tissue culture demonstrated that suppressing VEGF in Muller cells led to Muller cell death, indicating an autocrine role for VEGF in Muller cells (i.e. Muller cells both make VEGF and use it for survival). Further, they used cultures of freshly isolated photoreceptors to show that VEGF can act as a protectant for these cells.

"Insight into the complex role of VEGF in the eye and in other parts of the body indicates that increased care should be taken in the long-term use of these drugs and that this new information should be considered in the design of future clinical studies to ensure that these possible side effects are taken into account," says D'Amore.

"Mice eyes differ from human eyes in many ways, so we cannot directly extrapolate these results to humans, but this study is an important heads-up that clinical application of anti-VEGF therapy in the eye needs to proceed with caution," she adds.

From a clinical perspective, Dr. Del
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