Hematopoietic stem cells are isolated by monoclonal antibody staining and flow cytometry from normal individuals as well as from patients with sickle cell anemia. Stem cell activity is determined utilizing in vitro long term bone marrow cultures and limiting dilution assays with the intent of characterizing the self renewal and developmental potential of a stem cell population within these patients. Efforts on in vitro stem cell expansion have concentrated on the use of endothelial cell coculture to enhance engraftment potential and gene therapy of the primitive hematopoietic stem cells. A porcine cerebral microvasculature cell line is the focus of studies to genetically modify stem cells in vitro without differentiation or loss of function. In addition, his laboratory is investigating the regulation of human megakaryocytopoiesis, including the role of cytokines on the proliferation and maturation of these cells.
Megakaryocytes are responsible for production of platelets within the body.
During transplantation and hematologic trauma large numbers of platelets are necessary for timely recovery. Recently, Dr. Hoffman s laboratory has found a novel primitive megarkaryocyte progenitor cell that exhibits a high level of proliferative potential. This cell population may have clinical benefits in the improvement of bone marrow transplantation and in the production of novel blood products.