Researchers at Schepens Eye Research Institute have found that when the eye is missing a diffusible form of vascular endothelial growth factor (VEGF), i.e. one that when secreted can reach other cells at a distance, the retina shows defects similar geographic atrophy (GA). This study was published in the November 3, 2009 print edition of PNAS (Proceedings of the National Academy of Sciences) and it may also impact the use of anti-VEGF drugs and further the understanding of GA.

The Schepens team hypothesized that in a healthy individual, the RPE produces forms of VEGF that, when secreted, can move away from the RPE and reach the underlying choriocapillaris to support its function and survival.  In the PNAS study, the researchers tested their hypothesis using a genetic mouse model in which the RPE produced a form of VEGF that was unable to diffuse. As the mice aged, they began to display an age-dependent degeneration of both the choriocapillaris and RPE, culminating with the death of photoreceptors and vision loss, similar to that observed in GA.

The next step in the research is to determine if this model can be used to investigate the role of RPE-choriocapillaris interaction in AMD and to design new therapies.

Read the abstract/article here ^[1] (log in required).