Enhanced maintenance and retroviral transduction of primitive hematopoietic progenitor cells using a novel three-dimensional culture system.

Current techniques for the in vitro maintenance of hematopoietic stem cells often lead to loss of pluripotency. Overcoming the technical difficulties that result in alterations in stem cells in vitro has important implications for areas of basic science and clinical medicine such as cell expansion, bone marrow transplantation and gene therapy. Recent insights into hematopoietic stem cell biology have demonstrated that the three-dimensional architecture of the culture environment may influence the maintenance of stem cell pluripotency in vitro. An intriguing hypothesis is that the utilization of three-dimensional culture systems may improve the maintenance and manipulation of these cells in vitro. We report that a novel, three-dimensional, tantalum-coated porous biomaterial (TCPB) may be employed effectively as a hematopoietic progenitor cell culture device that offers distinct advantages over conventional culture systems. Specifically, we demonstrate that the use of TCPB for culturing hematopoietic progenitor cells in the absence of exogenous cytokines results in enhanced hematopoietic progenitor cell survival, improved maintenance of the immature CD34+/38- phenotype, and improved retroviral transduction of CD34+ cells and long-term culture 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 useful in advancing the in vitro culture and transduction of hematopoietic stem and progenitor cells.