ENHANCED MAINTENANCE AND RETROVIRAL TRANSDUCTION OF PRIMITIVE HEMATOPOIETIC PROGENITOR CELLS USING A NOVEL 3-DIMENSIONAL CULTURE SYSTEM

Current techniques for the in vitro maintenance of hematopoietic stem cells often lead to loss of pluripotency. Overcoming the technical dif ficulties that result in alterations in stem cells in vitro has import ant implications for areas of basic science and clinical medicine such as cell expansion, bone marrow transplantation and gene therapy. Rece nt insights into hematopoietic stem cell biology have demonstrated tha t the three-dimensional architecture of the culture environment may in fluence the maintenance of stem cell pluripotency in vitro. An intrigu ing hypothesis is that the utilization of three-dimensional culture sy stems may improve the maintenance and manipulation of these cells in v itro. We report that a novel, three-dimensional, tantalum-coated porou s biomaterial (TCPB) may be employed effectively as a hematopoietic pr ogenitor cell culture device that offers distinct advantages over conv entional culture systems. Specifically, we demonstrate that the use of TCPB for culturing hematopoietic progenitor cells in the absence of e xogenous cytokines results in enhanced hematopoietic progenitor cell s urvival, improved maintenance of the immature CD34(+)/38(-) phenotype, and improved retroviral transduction of CD34(+) cells and long-term c ulture initiating cells (LTCIC), without compromising multipotency, as compared with cultures in plastic dishes or bone marrow stroma. These findings suggest that this three-dimensional culture system may be us eful in advancing the in vitro culture and transduction of hematopoiet ic stem and progenitor cells.