Ex Vivo Expansion of CD34+ Cells From Cord Blood, Bone Marrow, and Mobilized Peripheral Blood Using NANEX Nanofiber Scaffold

Abstract 4816

Hematopoietic stem cell (HSC) transplantation has become the standard of care for patients with hematologic cancers, anemia, and a variety of other malignant and non-malignant disorders, with greater than 50,000 such procedures being performed globally each year, according to the Worldwide Network for Blood and Marrow Transplantation. Although mobilized peripheral blood (MPB) has become a preferred source of HSCs for transplants, bone marrow (BM) and umbilical cord blood (UCB) are also frequently utilized. Regardless of source, several groups have reported that grafts containing lower total nucleated cell (TNC) and CD34+ cell doses contribute to delayed engraftment and higher graft failure rate. Therefore, methods to increase the total cell number while maintaining the progenitor phenotype, especially the CD34+ progenitor cells, from individual grafts would have a significant clinical impact.

Ex vivo expansion of HSCs prior to transplantation is one approach that offers tremendous promise for increasing cell doses and improving clinical outcomes. In many ex vivo culture systems, HSCs are cultured as a suspension cells and cultured in the presence of various media additives that act to enhance cell proliferation while reducing differentiation. An often-overlooked factor influencing fate decisions is the interaction of HSCs with a substrate. In the natural bone marrow microenvironment, HSCs maintain close contact with a complex network of stromal cells and extracellular matrix, likely indicating that cell-cell and cell-matrix interactions play an important role in maintaining their stem cell phenotype. With the goal of mimicking the bone marrow stem cell niche, Arteriocyte, Inc. has developed a 3-D NANEX nanofiber based cell culture substrate. The functionalized NANEX substrate is designed to provide topographical and substrate-immobilized biochemical cues that act in synergy with media additives to enhance HSC proliferation while maintain the progenitors stem cell phenotype.

Here, we present our recent work with the NANEX platform towards comparing and achieving a high yield ex vivo expansion of CD34+ cells from MPB, BM, and UCB. Additionally, through the use of flow cytometry and CFU assays, we quantify and characterize NANEX-expanded cells from each source. Furthermore, we compared NANEX to a variety of commercially available products and demonstrate that NANEX significantly improves expansion and reduces phenotype loss during ex vivo culture. Our data indicates that NANEX technology provides a robust ex vivo expansion of HSCs and, with further GMP and clinical development, offers great potential for clinical applications.