0 10 20 30 40 50 0 50 100 150 Time (hrs) % Resistance No Exposure VEGF IL-6/R VEGF + IL-6/R ↑ Exposure Start IL-6 and VEGF each disrupt the blood-retinal barrier independently. When combined, they cause an even greater loss of barrier integrity Ocular inflammation damages tight junctions between endothelial cells • This compromises the integrity of the blood retina barrier, which increases vascular permeability • The integrity of the blood- retinal barrier can be measured by barrier resistance Exposure to both IL-6/R and VEGF additively induces greater loss in barrier function than either IL-6 or VEGF alone • As measured by decreased barrier resistance in human umbilical vein endothelial cells (HUVEC) HUVEC cells were treated as indicated after growth to establish barrier Assessing vascular endothelial barrier integrity using electrical resistance measurements High barrier resistance from intact tight junctions IL-6/R and VEGF induce a greater loss of barrier resistance and function than either VEGF or IL-6 alone 43