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Comparative analysis of multipotent mesenchymal stromal cells from human bone marrow, umbilical cord and adipose tissue
thesisposted on 2017-02-14, 00:53 authored by Mathias, Louisa Jane
Cytoablative therapies and generalised immunosuppressants used to treat cancer often leave patients susceptible to opportunistic infections. Immune regeneration post hematopoietic stem cell transplantation (HSCT) can be delayed; especially in the elderly and in some instances, full recovery is never achieved. Furthermore, some patients develop steroid resistant Graft-versus- Host Disease (GvHD), which is associated with morbidity and mortality. Multipotent mesenchymal stromal cells (MSCs) are a population of stromal cells that have been shown to enhance hematopoietic recovery. In addition to this, clinical studies have shown that MSCs can be effective at reducing and in some cases eliminate GvHD. MSCs are traditionally sourced from the bone marrow (BM). However, the BM is not a rich source of these cells and collection of BM from the donor is invasive. Therefore, an alternative source may be required. The umbilical cord (UC) and adipose (Ad) tissue contain cells that possess a similar phenotype and function to BM MSCs. A comparative analysis of BM, UC and Ad MSCs may provide an alternative source for therapeutic use. Therefore we isolated MSCs from the UC and Ad and compared them to BM for their growth in vitro, differentiation potential and immunomodulation of leukocyte proliferation in the presence and absence of inflammatory cytokines. The in vivo function of these cells was examined by their relative ability to enhance hematopoietic recovery in a model of BMT and their ability to reduce inflammation in asthma. We were able to routinely isolate MSCs from the UC and Ad. The cells obtained from these tissues were heterogeneous and included leukocytes and endothelial cells, with the UC also containing epithelial cells. MSCs were purified by standard plastic adherence and these were further expanded in culture over multiple passages. Functional differences in self renewal and multipotency were observed between donors, however, UC MSCs were overall less proliferative than BM and Ad MSCs, and less readily differentiated. We found that the MSC phenotype from each source was comparable, and that MSCs from each source also expressed the fibroblast and pericyte surface proteins, PDGFR-! and CD146. Interferon-", TNF and IL-17 treatment did not change the fibroblast colony forming unit (CFU-F) potential of the MSCs or general phenotype, except for Human Leukocyte Antigen (HLA) iv expression and this was cytokine dependant. Adipose MSCs reduced peripheral blood mononuclear cell (PBMC) proliferation in a mixed lymphocyte reaction (MLR) more efficiently than UC and BM MSCs. Interestingly, however, PBMCs proliferated at a low level in response to MSCs in co-culture. We found that pre-treatment with IFN-" enhanced the suppressive ability of both BM and Ad MSCs, but not UC MSCs. BM MSCs exclusively enhanced hematopoiesis in congenic but not allogeneic BMT and this was dependent on the dose of BM cells transplanted. BM, UC and Ad MSCs reduced inflammation in an asthma model and we found that Ad MSCs were also able to reduce T cell proliferation in this model. Collectively, this data suggests that adipose tissue represents a good alternative source of MSCs for the treatment of inflammatory conditions, however, BM MSCs remain the best source of MSCs to enhance hematopoieisis in vivo.