Evaluating Interaction of Cord Blood Hematopoietic Stem/Progenitor Cells with Functionally Integrated Three-Dimensional Microenvironments

Abstract

Despite advances in ex vivo expansion of cord blood‐derived hematopoietic stem/progenitor cells (CB‐HSPC), challenges still remain regarding the ability to obtain, from a single unit, sufficient numbers of cells to treat an adolescent or adult patient. We and others have shown that CB‐HSPC can be expanded ex vivo in two‐dimensional (2D) cultures, but the absolute percentage of the more primitive stem cells decreases with time. During development, the fetal liver is the main site of HSPC expansion. Therefore, here we investigated, in vitro, the outcome of interactions of primitive HSPC with surrogate fetal liver environments. We compared bioengineered liver constructs made from a natural three‐dimensional‐liver‐extracellular‐matrix (3D‐ECM) seeded with hepatoblasts, fetal liver‐derived (LvSt), or bone marrow‐derived stromal cells, to their respective 2D culture counterparts. We showed that the inclusion of cellular components within the 3D‐ECM scaffolds was necessary for maintenance of HSPC viability in culture, and that irrespective of the microenvironment used, the 3D‐ECM structures led to the maintenance of a more primitive subpopulation of HSPC, as determined by flow cytometry and colony forming assays. In addition, we showed that the timing and extent of expansion depends upon the biological component used, with LvSt providing the optimal balance between preservation of primitive CB HSPC and cellular differentiation. Stem Cells Translational Medicine 2018;7:271–282

Advances in ex vivo expansion of hematopoietic stem and progenitor cells for clinical applications

“…Taking advantage of extramedullary niches where HSC naturally go through an extensive expansion phase during development, the fetal liver has been hypothesized to be an exciting alternative to the model. Ferret-derived fetal livers were decellularized and repopulated with human fetal liver-derived stromal cells before infusing UCB HSC and HPC ( Mokhtari et al, 2018 ). This top-down approach harnessed in vivo produced ECM with native structure to better recreate the fetal liver niche.…”

DNA barcode to trace the development and differentiation of cord blood stem cells (Review)

“…Demerdash et al (25) indicated that the number of expansion times of the feeder culture system were limited and that the growth ability of UCBSCs was reduced following differentiation for a certain number of generations. Furthermore, the authors of that study demonstrated that feeder layer cells weakened the effect of exogenous factors on UCBSCs and the animal/human-derived feeder layer was unable to achieve its clinical effect due to contamination with heterogenic/allogeneic antigens (23,(26)(27)(28)(29).…”

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“…However, current 2D in vitro culture and expansion strategies lead to a reduction in the absolute percentage of the most primitive stem cell number over time, so reducing the regenerative potential of CB. A new S tem C ells T ranslational M edicine study from the laboratories of Shay Soker and Graça Almeida‐Porada (Wake Forest Institute for Regenerative Medicine, North Carolina, USA) recently explored CB culture using conditions that mimic the 3D fetal liver niche of primitive HSPCs . To this end, Mokhtari et al developed a 3D scaffold constructed from extracellular matrix components seeded with liver or bone marrow cells and, encouragingly, the recreation of a 3D niche inhibited the decrease in the proportion of primitive HSPCs during culture and expansion, irrespective of the cell type used.…”