Morphology, phagocytosis, and vitamin A metabolism of cultured human retinal pigment epithelium

We have developed a simple assay for the quantitative and qualitative study of phagocytosis in cultured human pigment epithelial cells. This in vitro system, both with latex particles, and later rod outer segments, should be helpful in evaluating the effects of drugs and environmental conditions on the phagocytic activity of human RPE, and should also prove a useful method to explore the role of phagocytosis in various human diseases of the choroid and retina, especially in retinitis pigmentosa. In addition, our studies suggest that human RPE growing in tissue culture continues to produce cytoplasmic retinol binding protein. These in vitro cultures of human RPE should prove useful for the study of vitamin A metabolism in normal human retinal pigment epithelium as well as in exploring the role of retinol metabolism in various human retinal disorders.