Cryoprecipitate: An autologous substrate for human fetal retinal pigment epithelium

Purpose. To harvest thin membranes from cryoprecipitates isolated from huma n blood donors and utilize them as substrates for the adhesion of human fet al retinal pigment epithelial (HFRPE) cells. Methods. Frozen human cryoprecipitates from anonymous blood donors were obt ained from the blood bank. Thin cryo-membranes were harvested by their mixt ure 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 con trast and electron microscope. Cell proliferation was evaluated by their in corporation of 5-bromo-2'-deoxyuridine (BrdU). Functional viability was ass essed 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 c ells maintained their cuboidal morphology and did not dedifferentiate. The cells subsequently proliferated and migrated onto the culture plate, formin g 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 isolat ion from the recipient's blood grants an additional advantage for their app lication as a carrier for HFRPE transplantation into the subretinal space.