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Cytomatrix |
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Neuronal, Mesenchymal and Hematopoietic Cell Derived from CD34-Lin- Cell from Adult Bone Marrow |
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N. Banu, J. Reitter, K. Biber, E. Vonschild, M. Rosenzweig, M. Pykett
Cytomatrix, Woburn, MA |
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Recent studies have demonstrated that fibroblast like CD34- cells derived from the hematopoitic system have the potential to give rise to cells of diverse tissues types. To investigate the plasticity of the bone marrow derived cells, we performed an experiment containing series of different targeted culture systems. We isolated CD34-/Lin- cells from human adult bone marrow and established cultures for hematopoietic stem cells (HSC), mesenchymal stem cells (MSC) and neural stem cells (NSC) respectively. After 3 to 4 weeks, the cultures were harvested and evaluated by flow cytometry. From MSC cultures, which consist of MSC growth medium and growth factors, CD45-Cytokeratin+ (epithelial) and CD45-Vimentin+ (mesenchymal) cells were obtained. When vascular endothelial growth factor was added to the culture medium, cell expressing the endothelial cell surface marker vwf were observed. Cells isolated from hematopoietic growth culture medium supplemented with hematopoietic growth factors were predominantly CD45+CD34+CD38+. Cells cultured in neuronal growth medium and growth factors expressed neurofilament. The morphology of the cells in these three growth specific culture media was markedly different. To extend this work and asses the in vivo attributes of in vitro derived cells, cells derived from bone marrow CD34-Lin- cells cultured for 3 weeks in differentiation culture for neuronal cell growth were injected into irradiated NOD/SCID mice. After 18 days, mice were sacrificed and cells from the brain, muscle, thymus, spleen, and bone marrow were collected and stained with antibodies specific to human CD45 and MHC class-1. Human cells (CD45+ or MHC class 1+) were only identified in the brain, but not in other mouse tissues. To further confirm the FACS observation, PCR for human globin was performed which again indicated the presence of human cells only in the brain of the transplanted mice. Muscle cells of the transplanted mice and the brain and muscle of the untransplanted control mice did not show evidence for human globin. These data indicate that HSC, MSC and NSC may originate from a common precursor or pool of precursors in the CD34-/Lin- fraction of human bone marrow. These precursor cells have strong requirements for defining growth environments to enable their differentiation into particular lineages. The data also suggest that the homing of the injected cells may be organ specific. Immunohistochemistry should further reveal the nature of these cells.   |
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