Continuous activation of primitive hematopoietic cells in long-term human marrow cultures containing irradiated tumor cells

Are Stem Cell Characteristics Altered by Disease State?

Autologous stem cell transplantation combined with gene therapy can potentially be used to treat genetically inherited diseases. However, characterization of multipotential cells from a disease state remains extremely limited. We have characterized adult bone marrow stromal cells (MSCs) derived from three retinal degenerative mouse models and compared them to marrow stromal cells derived from their normal strain counterparts. Despite similar profiles soon after harvest, at 30 days postisolation, marrow stromal cells derived from a disease origin were shown to contain a large pool (approximately 89-99%) of undifferentiated marrow stromal cells (CD90(+)/STRO-1(+)) as compared to their normal counterparts (approximately 19-43%). Fetal bovine serum appeared essential for marrow stromal cell proliferation and was not found to induce differentiation, although it could be substituted with other additives including epidermal growth factor (EGF), platelet-derived growth factor (PDGF), and leukemia inhibitory factor (LIF). We also showed that resulting CD90(+)/STRO(+) cells derived from both states could be directed into desired lineages expressing at the same rate and that they could be transduced with the same efficiency using different viral vehicles. This investigation has shown the existence of a large pool of undifferentiated stem cells derived from the disease state that have the potential to form the desired cell types when appropriately cued.

Marrow stromal cells as stem cells for nonhematopoietic tissues

Marrow stromal cells can be isolated from other cells in marrow by their tendency to adhere to tissue culture plastic. The cells have many of the characteristics of stem cells for tissues that can roughly be defined as mesenchymal, because they can be differentiated in culture into osteoblasts, chondrocytes, adipocytes, and even myoblasts. Therefore, marrow stromal cells present an intriguing model for examining the differentiation of stem cells. Also, they have several characteristics that make them potentially useful for cell and gene therapy.

Effects of Bestatin on hematopoiesis in long-term human bone marrow cultures

The effects of Bestatin (Ubenimex, UBX) on normal hematopoiesis were investigated using long-term bone marrow cultures (LTBMC) to determine whether it might enhance hematopoiesis over a long period, as well as induce the release of cytokines. LTBMC were inoculated with 0.1 or 1.0 microgram/ml of UBX at the onset of culture and was added at each weekly medium change. The cellularity and the content of the progenitors in nonadherent layer were examined each week for 5 weeks; those from the adherent layer were examined at week 5. The number of the nucleated mature cells and that of the myeloid progenitors from the nonadherent layer increased significantly (approximately two-fold) following treatment with UBX vs controls. The total number of colonies and the number of myeloid progenitors, but not that of erythroid progenitors, from the adherent layer increased significantly (about 1.5-fold) following treatment with 1.0 microgram/ml UBX. The level of interleukin-6 (IL-6) in the culture supernatants was significantly increased one day after the addition of 1.0 microgram/ml UBX. Findings indicate that UBX stimulated both the production of mature cells and myeloid progenitors on normal hematopoiesis in LTBMC. This was mediated by an indirect action via IL-6 production.