Human Cord Blood Hematopoietic Cells Research Articles

Engineering human mini-bones for the standardized modeling of healthy hematopoiesis, leukemia, and solid tumor metastasis.

The bone marrow microenvironment provides indispensable factors to sustain blood production throughout life. It is also a hotspot for the progression of hematologic disorders and the most frequent site of solid tumor metastasis. Preclinical research relies on xenograft mouse models, but these models preclude the human-specific functional interactions of stem cells with their bone marrow microenvironment. Instead, human mesenchymal cells can be exploited for the in vivo engineering of humanized niches, which confer robust engraftment of human healthy and malignant blood samples. However, mesenchymal cells are associated with major reproducibility issues in tissue formation. Here, we report the fast and standardized generation of human mini-bones by a custom-designed human mesenchymal cell line. These resulting humanized ossicles (hOss) consist of fully mature bone and bone marrow structures hosting a human mesenchymal niche with retained stem cell properties. As compared to mouse bones, we demonstrate superior engraftment of human cord blood hematopoietic cells and primary acute myeloid leukemia samples and also validate hOss as a metastatic site for breast cancer cells. We further report the engraftment of neuroblastoma patient-derived xenograft cells in a humanized model, recapitulating clinically described osteolytic lesions. Collectively, our human mini-bones constitute a powerful preclinical platform to model bone-developing tumors using patient-derived materials.

Human cord blood hematopoietic cells acquire neural features when cultured in the presence of neurogenic cytokines

In vitro growth of hematopoietic cells depends on the presence of hematopoietic cytokines. To date, it is unclear if these cells would be able to respond to non-hematopoietic cytokines. In the present study, we have explored this by culturing human hematopoietic cells in presence of neurogenic cytokines. Lineage-negative (Lin−) umbilical cord blood (UCB)-derived cells -enriched for hematopoietic stem and progenitor cells- were cultured in presence of different combinations of hematopoietic cytokines, neurotrophins, epidermal growth factor, fibroblast growth factor, and neurogenic culture media, in a 3-phase culture system. A proportion (1–22%) of Lin− UCB hematopoietic cells normally express neural markers and are capable of responding to neural cytokines. Neural cytokines did not have effects on hematopoietic cell proliferation; however, we observed generation of neural-like cells, assessed by morphology, and a significant increase in the proportion of cells expressing neural markers. Such neural-like cells, however, retained expression of hematopoietic markers. It seems that under our culture conditions, no actual transdifferentiation of hematopoietic cells into neural cells occurred; instead, the cells generated in culture seem to be hematopoietic cells that acquired neural features upon contact with neurogenic factors. The identity of UCB cells that acquired a neural phenotype is still unclear.

Background and Future Considerations for Human Cord Blood Hematopoietic Cell Transplantation, Including Economic Concerns

Cord blood (CB) has been used since 1988 as a source of hematopoietic stem cells (HSCs) and progenitor cells for hematopoietic cell transplantation (HCT) to treat patients with malignant and nonmalignant disorders. CB has both advantages and disadvantages when compared with other tissue sources of HSCs such as bone marrow and mobilized peripheral blood, which are also being used in the setting of HCT. This short review focuses on some historical information, as well as current efforts that are being assessed to enhance the efficacy of CB HCT. Also of importance are the costs of CB, and the feasibility and economics of using such to be identified, and newly confirmed improvements worldwide for the greatest number of patients. In this context, simple methods that would not necessarily entail the need for selected cell-processing facilities to ex vivo expand or improve the CB graft's functional activity may be of interest, with one such possibility being the use of an orally active inhibitor of the enzyme dipeptidylpeptidase 4, alone or in combination with other new and innovative approaches for improving HSC engraftment and in vivo repopulating capability of CB.

Co-infusion of ex vivo-expanded, parental MSCs prevents life-threatening acute GVHD, but does not reduce the risk of graft failure in pediatric patients undergoing allogeneic umbilical cord blood transplantation

When compared with BMT, umbilical cord blood transplantation (UCBT) is associated with a lower rate of engraftment and delayed hematological/immunological recovery. This leads to increased risk of TRM in the early post transplantation period due to infection. Acute GVHD, although occurring less frequently in UCBT compared with BMT, is also significantly associated with increased rate of early TRM. BM MSCs are known to support normal in vivo hematopoiesis, and co-transplantation of MSCs has been shown to enhance engraftment of human cord blood hematopoietic cells in nonobese diabetic/SCID mice. In 13 children with hematological disorders (median age 2 years) undergoing UCBT, we co-transplanted paternal, HLA-disparate MSCs with the aim of improving hematological recovery and reducing rejection. We observed no differences in hematological recovery or rejection rates compared with 39 matched historical controls, most of whom received G-CSF after UCBT. However, the rate of grade III and IV acute GVHD was significantly decreased in the study cohort when compared with controls (P=0.05), thus resulting in reduced early TRM. Although these data do not support the use of MSCs in UCBT to support hematopoietic engraftment, they suggest that MSCs, possibly because of their immunosuppressive effect, may abrogate life-threatening acute GVHD and reduce early TRM.

G-CSF- and GM-CSF-induced upregulation of CD26 peptidase downregulates the functional chemotactic response of CD34 +CD38 − human cord blood hematopoietic cells

Cytokine treatment with granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and stem cell factor (SCF) is a mainstay of current and future clinical and research protocols for peripheral blood stem cell mobilization, therapeutic care after hematopoietic stem cell transplantation (HSCT), and ex vivo hematopoietic stem and progenitor cell (HSC/HPC) expansion. We have previously shown that the peptidase CD26 (DPPIV/dipeptidylpeptidase IV) negatively regulates HSC/HPC and that inhibition of CD26 improves the chemotactic ability and trafficking of HSC/HPC. We set out to establish whether short-term in vitro G-CSF, GM-CSF, or SCF treatment upregulates CD26 and thereby has a detrimental effect on the chemotactic potential of HSC/HPC that could be reversed by CD26 inhibitor treatment. CD34+ or CD34+CD38- cells, a population enriched in HSC, were isolated from human umbilical cord blood and subjected to G-CSF, GM-CSF, or SCF treatment. We then evaluated CD26 expression, CD26 activity, and CXCL12 (SDF-1)-induced migration in the presence or absence of a CD26 inhibitor, Diprotin A. Treatment with G-CSF and GM-CSF but not SCF upregulates CD26 expression and activity resulting in a CD26 inhibitor-reversible downregulation of CXCL12-induced chemotactic response. Short-term in vitro G-CSF and GM-CSF treatment upregulates the peptidase CD26, resulting in downregulation of the functional ability of CD34+CD38- cells to respond to the chemokine CXCL12. This suggests that current and future clinical protocols utilizing G-CSF and GM-CSF may have unforeseen detrimental effects on the trafficking of HSC/HPC during HSCT that can be overcome through the use of CD26 inhibitors.

961. Influence to Gene Expression of Human Cord Blood Hematopoietic Cells by Gene Transduction Using a Third-generation Self-inactivating Lentiviral Vector

961. Influence to Gene Expression of Human Cord Blood Hematopoietic Cells by Gene Transduction Using a Third-generation Self-inactivating Lentiviral Vector