Cryoprecipitate: An autologous substrate for human fetal retinal pigment epithelium

Purpose. To harvest thin membranes from cryoprecipitates isolated from human blood donors and utilize them as substrates for the adhesion of human fetal retinal pigment epithelial (HFRPE) cells. Methods. Frozen human cryoprecipitates from anonymous blood donors were obtained from the blood bank. Thin cryo-membranes were harvested by their mixture with riboflavin5-phosphate (R5P) and overnight exposure to ultra-violet light. Sheets of retinal pigment epithelium (RPE) were isolated from fetal eyes at 17-22 weeks gestational age. The sheets were subsequently attached to cryo-membranes. The morphology of the cells was examined with phase contrast and electron microscope. Cell proliferation was evaluated by their incorporation of 5-bromo-2'-deoxyuridine (BrdU). Functional viability was assessed by rod outer segment (ROS) phagocytosis. Results. Thin membrane films were made from isolated human cryoprecipitates. Isolated sheets of pure HFRPE cells were attached to the membranes. The cells maintained their cuboidal morphology and did not dedifferentiate. The cells subsequently proliferated and migrated onto the culture plate, forming cellular monolayers. The cultured cells phagocytized isolated ROS. Conclusions. Cryoprecipitate membranes may provide an ideal source for the adhesion, cultivation, and transfer of HFRPE cells. Their autologous isolation from the recipient's blood grants an additional advantage for their application as a carrier for HFRPE transplantation into the subretinal space.