Spatiotemporal mapping of erythroid, stromal, and osteogenic niche formation to support physiologic red cell production in a three-dimensional hollow fibre perfusion bioreactor (Conference Abstract)

Current in vitro human erythroid culture platforms require abnormally high cytokine supplementation and use lower cell density (6/mL) compared with that present in bone marrow during physiologic erythropoiesis. These in vitro culture conditions limit extracellular interactions, are not dynamic, and exhaust stem and progenitor cell pools, thereby limiting culture longevity. We have developed a three-dimensional hollow fibre perfusion bioreactor (HFBR) comprised of a collagen-coated polyurethane scaffold which surrounded ceramic hollow fibres (HFs) and expanded dense inocula of human umbilical cord blood (CB) mononuclear cells (MNCs; >107/mL) when perfused with cytokine-free media in long-term culture. In order to study the role of this manufactured HFBR microenvironment on spatiotemporal physiologic erythropoiesis, we now extend our previous reports by implementing 5-fold less cytokine concentrations than those used in typical ex vivo erythropoietic cultures. Herein, we show a >107 red cell harvest from the HFBR culture over 28-days with spontaneous expansion of stromal cells, maintenance of erythroid progenitor pools, and formation of stromal and erythroid cell niches in defined areas within the HFBR structure with differential in situ production of 23 growth factors varying over time..