Utilization of cord blood-expanded stem cells for megakaryocyte and platelet production

DESCRIPTION provided by applicant Platelet transfusions are the most effective treatments for patients with thrombocytopenia The growing demand for platelet transfusions is often limited by shortage in the platelets PTL supply due to dependency on volunteer donors short shelf life risk of infections and alloimmunization It is therefore critical to create an efficient donor independent source of PTLs that could complement and possibly replace the current donor dependent transfusion system The search for a different source of platelets for transfusion was accelerated by the recent advances in hematopoietic stem cell expansion which became a promising source for generating platelets ex vivo However creating a clinically relevant platelet product ex vivo has been hampered by technological and quantitative limitations The major barrier in generating PTLs suitable for transfusion is the low number of PTLs that can be produced by cultured megakaryocytes MK ex vivo and the difficulties in recapitulating the complexity of physiological human thrombopoiesis in culture The studies proposed in this application are designed to develop an alternative approach by creating a MK cell product that can generate platelets in vivo after its transfusion into patients Creating such
product will not only circumvent the technological hurdles and costs associated with ex vivo PTL production but also provide the foundation for developing a cell based therapy for thrombocytopenic patients and possibly preclude alloimmunization In addition MKs generated from this study will be advanced to a manufacturing phase to create the first commercially available source of CD MKs for use in research A commercial supply of MKs would dramatically accelerate the pace of research in human thrombopoiesis This goal will be accomplished by implementing a new culture system protocol in which a MK cell product comprising MK progenitors precursors immature MKs and mature MKs will be generated from a validated source of cord blood derived CD hematopoietic stem cells expanded by means of epigenetic reprograming by treatment with valproic acid These proposed feasibility studies are designed to characterize the resultant MKs phenotypically and functionally determine the MKsandapos potency ex vivo and in vivo in transplantation assays in an immunodeficient mouse model and test the MKsandapos ability to remain viable and functional following cryopreservation and storage These studies will lead to development of a platform for developing a commercial MK cell product for clinical use to treat thrombocytopenia and for laboratory research

PUBLIC HEALTH RELEVANCE Utilization of cord blood expanded stem cells for megakaryocyte and platelet production Platelets are small blood cells that help stop bleeding patients with various diseases can develop thrombocytopenia or low platelet count which is often treated with platelet transfusions from a relatively small pool of volunteer donors This project will develop a new therapy that creates healthy platelet making cells that can be given to thrombocytopenic patients to make new platelets within the patientsandapos own bodies Our approach will not only solve many technical issues surrounding platelet collection and storage but could also bypass the need for platelet donors and prevent a dangerous reaction that sometimes follows platelet transfusions