Engraftment Outcomes after HPC Co-Culture with Mesenchymal Stromal Cells and Osteoblasts

• Main Authors: Matthew M. Cook, Michael R. Doran, Katarina Kollar, Valerie Barbier, Ingrid G. Winkler, Jean-Pierre Levesque, Gary Brooke, Kerry Atkinson
• Format: Article
• Language: English
• Published: MDPI AG 2013-09-01
• Series: Journal of Clinical Medicine
• Subjects: haematopoietic stem cells; mesenchymal stromal cells; osteoblasts; ex vivo expansion; haematopoietic reconstitution
• Online Access: http://www.mdpi.com/2077-0383/2/3/115

Haematopoietic stem cell (HSC) transplantation is an established cell-based therapy for a number of haematological diseases. To enhance this therapy, there is considerable interest in expanding HSCs in artificial niches prior to transplantation. This study compared murine HSC expansion supported through co-culture on monolayers of either undifferentiated mesenchymal stromal cells (MSCs) or osteoblasts. Sorted Lineage− Sca-1+ c-kit+ (LSK) haematopoietic stem/progenitor cells (HPC) demonstrated proliferative capacity on both stromal monolayers with the greatest expansion of LSK shown in cultures supported by osteoblast monolayers. After transplantation, both types of bulk-expanded cultures were capable of engrafting and repopulating lethally irradiated primary and secondary murine recipients. LSKs co-cultured on MSCs showed comparable, but not superior, reconstitution ability to that of freshly isolated LSKs. Surprisingly, however, osteoblast co-cultured LSKs showed significantly poorer haematopoietic reconstitution compared to LSKs co-cultured on MSCs, likely due to a delay in short-term reconstitution. We demonstrated that stromal monolayers can be used to maintain, but not expand, functional HSCs without a need for additional haematopoietic growth factors. We also demonstrated that despite apparently superior in vitro performance, co-injection of bulk cultures of osteoblasts and LSKs in vivo was detrimental to recipient survival and should be avoided in translation to clinical practice.