Noninvasive Measurement of Retinal Microvascular Permeability During Loss of Endothelial Quiescence.

In the retina EC dysfunction and angiogenesis are driven by an altered microenvironment e.g., diabetes, leading to hypoxia and inflammation in the retinal layers, resulting in excessive vascular leakage and growth. The gold standard for measuring blood-retinal barrier permeability in response to disease and or therapy has been the gold standard Evans blue (EB) assay. However, this technique has limitations in vivo, including nonspecific tissue binding and toxicity. Here we describe a novel imaging methodology combining sodium fluorescein fundus angiography (FFA) with mathematical quantification allowing retinal permeability to be noninvasively and accurately measured at multiple time points in the same animal, minimizing animal use in line with the 3Rs framework. In addition, this technique is a nontoxic, high throughput, sensitive, and cost-effective alternative technique to the Evans blue assay. Moreover, this technique can be translated to other species.