Ex vivo
 expansion of megakaryocyte progenitor cells from normal bone marrow and peripheral blood and from patients with haematological malignancies

The presence of primitive hematopoietic progenitor cells or stem cells in peripheral blood (PBSC's) harvests was investigated in a single cell culturing assay and compared with the results obtained in aspirates of normal bone marrow. Based on the presence of CD33, rather differentiated progenitor cells (CD34+/33+) were distinguished from more primitive cells (CD34+/33-). The growth potential of CD34+/33+ and CD34+/33- cells have been studied. Single cell sorting was performed from peripheral blood harvests, obtained from three patients with multiple myeloma during hematopoietic recovery after treatment with high dose cyclophosphamide and rhu-GM-CSF. To test the effect of “stem cell recruiting factors” the cells were sorted in 96-well plates, pre-filled with liquid medium both in the presence of IL-3 + G-CSF + GM-CSF + Epo and the same growth factors supplemented with SCF+ IL-6. Addition of SCF and IL-6 to the culturing medium enhanced the plating efficiency of CD34+/33- cells considerably more than that of CD34+/33+ cells. This was observed in harvests of peripheral blood as well as in aspirates of normal bone marrow. The differences between CD34+/33+ and CD34+/33- were even more pronounced when only the large colonies (>500 cells/well) were taken into consideration. Assuming that IL-6 and SCF are “stem cell recuiting factors”, the CD34+/33- fraction contains more clonogenic cells than the CD34+/33+ fraction. In all three patients the first CD34+ cells appearing in the peripheral blood (PB) after cytoreductive treatment were predominantly CD34+/33- (>80%). At later stages when the leukocyte counts had reached higher values the CD34+/33+ cells predominated. We conclude that peripheral blood stem cell harvests contain primitive multipotential clonogenic progenitor cells (of the CD34+/33- phenotype).

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Maintenance of transplantation potential in ex vivo expanded CD34(+)- selected human peripheral blood progenitor cells

Blood ◽

10.1182/blood.v84.9.2898.2898 ◽

1994 ◽

Vol 84 (9) ◽

pp. 2898-2903 ◽

Cited By ~ 108

Author(s):

R Henschler ◽

W Brugger ◽

T Luft ◽

T Frey ◽

R Mertelsmann ◽

...

Keyword(s):

Progenitor Cells ◽

Peripheral Blood ◽

Large Scale ◽

Ex Vivo ◽

Human Peripheral Blood ◽

Ex Vivo Expansion ◽

High Dose ◽

Peripheral Blood Progenitor Cells ◽

Limiting Dilution

Abstract CD34(+)-selected hematopoietic progenitor cells are being increasingly used for autotransplantation, and recent evidence indicates that these cells can be expanded ex vivo. Of 15 patients with solid tumors undergoing a phase I/II clinical trial using CD34(+)-selected peripheral blood progenitor cells (PBPCs) after high-dose chemotherapy, we analyzed the frequency of long-term culture-initiating cells (LTCIC) as a measure of transplantation potential before and after ex vivo expansion of CD34+ cells. PBPCs were mobilized by combination chemotherapy and granulocyte colony-stimulating factor (G-CSF). The original unseparated leukapheresis preparations, the CD34(+)-enriched transplants, as well as nonabsorbed fractions eluting from the CD34 immunoaffinity columns (Ceprate; CellPro, Bothell, WA) were monitored for their capacity to repopulate irradiated allogeneic stroma in human long-term bone marrow cultures. We found preservation of more than three quarters of fully functional LTCIC in the CD34(+)-selected fractions. Quantitation of LTCIC by limiting dilution analysis showed a 53-fold enrichment of LTCIC from 1/9,075 in the unseparated cells to an incidence of 1/169 in the CD34+ fractions. Thus, in a single apheresis, it was possible to harvest a median of 1.65 x 10(4) LTCIC per kg body weight (range, 0.71 to 3.72). In addition, in six patients, large-scale ex vivo expansions were performed using a five-factor cytokine combination consisting of stem cell factor (SCF), interleukin-1 (IL-1), IL-3, IL-6, and erythropoietin (EPO), previously shown to expand committed progenitor cells. LTCIC were preserved, but not expanded during the culture period. Optimization of ex vivo expansion growth factor requirements using limiting dilution assays for LTCIC estimation indicated that the five-factor combination using SCF, IL-1, IL-3, IL-6, and EPO together with autologous plasma was the most reliable combination securing both high progenitor yield and, at the same time, optimal preservation of LTCIC. Our data suggest that ex vivo-expanded CD34+ PBPCs might be able to allow long-term reconstitution of hematopoiesis.

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2'-Deoxycytidine protects normal human bone marrow progenitor cells in vitro against the cytotoxicity of 3'-azido-3'-deoxythymidine with preservation of antiretroviral activity

Blood ◽

10.1182/blood.v74.6.1923.1923 ◽

1989 ◽

Vol 74 (6) ◽

pp. 1923-1928 ◽

Cited By ~ 12

Author(s):

K Bhalla ◽

M Birkhofer ◽

GR Li ◽

S Grant ◽

W MacLaughlin ◽

...

Keyword(s):

Bone Marrow ◽

Progenitor Cells ◽

High Dose ◽

Normal Bone Marrow ◽

Normal Bone ◽

Bone Marrow Progenitor Cells ◽

Bone Marrow Progenitor ◽

High Concentrations ◽

Anti Hiv

Abstract Bone marrow cytotoxicity of 3′-azido-3′-deoxythymidine (AZT), an anti- human immunodeficiency virus (anti-HIV) drug, has been attributed to deoxyribonucleotide pool perturbations that might result in impaired DNA synthesis in normal bone marrow elements. We examined, in vitro, the effect of high, but clinically achievable and nontoxic, concentrations of 2′-deoxycytidine (dCyd) (greater than or equal to 100 mumol/L) on high-dose AZT mediated growth inhibition and intracellular biochemical perturbations in normal bone marrow progenitor cells. Colony formation by bone marrow progenitor cells in semisolid medium was significantly protected by dCyd against the inhibitory effects of co-administered, high concentrations of AZT (10 mumol/L). Also, dCyd significantly corrected AZT mediated depletion of intracellular thymidine triphosphate (dTTP) and dCyd triphosphate (dCTP) levels in normal bone marrow mononuclear cells (BMMC). Moreover, dCyd reduced the intracellular accumulation of AZT triphosphate (AZT-TP) and its DNA incorporation in BMMC. In contrast, co-administration of dCyd (100 mumol/L to 1 mmol/L) did not reverse AZT (10 mumol/L) mediated suppression of HIV infectivity in HUT-102 cells in culture, although a partial reduction in intracellular AZT-TP pools and its DNA incorporation as well as a correction of AZT mediated depletion of dTTP and dCTP pools was observed in these cells. These studies suggest that dCyd at high concentrations might ameliorate the bone marrow cytotoxicity of high-dose AZT without impairing its anti-HIV effect.

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Cytokines increase human hemopoietic cell adhesiveness by activation of very late antigen (VLA)-4 and VLA-5 integrins.

Journal of Experimental Medicine ◽

10.1084/jem.181.5.1805 ◽

1995 ◽

Vol 181 (5) ◽

pp. 1805-1815 ◽

Cited By ~ 234

Author(s):

J P Lévesque ◽

D I Leavesley ◽

S Niutta ◽

M Vadas ◽

P J Simmons

Keyword(s):

Bone Marrow ◽

Progenitor Cells ◽

Normal Bone Marrow ◽

Gm Csf ◽

Normal Bone ◽

Cd34 Cells ◽

Late Antigen ◽

Beta 1 Integrin ◽

Functional States ◽

Adhesive Interactions

Cytokines are known to be important regulators of normal hemopoiesis, acting in concert with components of the bone marrow microenvironment. Interactions with this microenvironment are known to regulate the proliferation, differentiation, and homing of hemopoietic progenitor (CD34+) cells. Adhesive interactions with the extracellular matrix retain CD34+ cells in close proximity to cytokines, but may also provide important costimulatory signals. Thus, the functional states of adhesion receptors are critical properties of CD34+ cells, but the physiological mechanisms responsible for regulating functional properties of cell adhesion receptors on primitive hemopoietic cells are still unknown. We confirm that the integrins very late antigen (VLA)-4 and VLA-5 are expressed on the CD34+ cell lines MO7e, TF1, and on normal bone marrow CD34+ progenitor cells, but in a low affinity state, conferring on them a weak adhesive phenotype on fibronectin (Fn). Herein, we show that the cytokines interleukin (IL)-3, granulocyte-macrophage CSF (GM-CSF), and KIT ligand (KL) are physiological activators of VLA-4 and VLA-5 expressed by MO7e, TF1, and normal bone marrow CD34+ progenitor cells. Cytokine-stimulated adhesion on Fn is dose dependent and transient, reaching a maximum between 15 and 30 min and returning to basal levels after 2 h. This cytokine-dependent activation is specific for VLA-4 and VLA-5, since activation of other beta 1 integrins was not observed. The addition of second messenger antagonists staurosporine and W7 abolished all cytokine-stimulated adhesion to Fn. In contrast, genistein inhibited KL-stimulated adhesion, but failed to inhibit GM-CSF- and IL-3-stimulated adhesion. Our data suggest that cytokines GM-CSF and IL-3 specifically stimulate beta 1 integrin function via an "inside-out" mechanism involving protein kinase activity, while KL stimulates integrin activity through a similar, but initially distinct, pathway via the KIT tyrosine-kinase. Thus, in addition to promoting the survival, proliferation, and development of hemopoietic progenitors, cytokines also regulate adhesive interactions between progenitor cells and the bone marrow microenvironment by modifying the functional states of specific integrins. These data are of importance in understanding the fundamental processes of beta 1 integrin activation and cellular response to mitogenic cytokines as well as on the clinical setting where cytokines induce therapeutic mobilization of hematopoietic progenitors.

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Characterization of ‘Early’ vs ‘Late’ Endothelial Progenitor Cells (EPCs) Which Are Derived from Human Umbilical Cord Blood (HCB) during Ex Vivo Expansion.

Blood ◽

10.1182/blood.v106.11.1706.1706 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1706-1706

Author(s):

Eun-Sun Yoo ◽

Jee-Young Ahn ◽

Yun-Kyung Bae ◽

Seung-Eun Lee ◽

Sang min Lee ◽

...

Keyword(s):

Bone Marrow ◽

Peripheral Blood ◽

Ex Vivo ◽

Tube Formation ◽

Ex Vivo Expansion ◽

Human Umbilical Cord ◽

Vascular Injuries ◽

Rt Pcr ◽

Different Types

Abstract EPCs have been isolated from adult peripheral blood and bone marrow. Recently, several groups reported that two types (‘early’ & ‘late’) of EPC could be isolated from peripheral blood and bone marrow when pertinent cocktails of cytokines were used. Interestingly, early and late EPCs are different in terms of expression of surface markers, the abilities of tube formation in vitro and the capabilities of re-vascularization on hind limb ischemia models in mice. We found EPC formation during ex vivo expansion of HCB and one EPC could be found from 314 CD34+ cells from HCB based on limiting dilutional assay (ref. Stem Cells; 2003, Yoo et al). However, little is known about the characteristics of ‘early’ and ‘late’ EPCs that are derived from HCB. In this study, our aims are to isolate the ‘early’ and ‘late’ EPCs from HCB during ex-vivo HCB expansion period and to characterize the biologic properties between ‘early’ and ‘late’ EPCs. 1 x 108 mononuclear cells were plated on a 100mm culture dish coated with 50ug/ml of human fibronectin (Calbiochem) and cultured in EGM-2 BulletKit system (Clonetics). Endothelial cells were assessed by colony counts, flow cytometry, proliferation assay, RT-PCR and in vitro tube formation in Matrigel plate. Migration of EPCs were also measured by in vitro transmigration assay in the presence of VEGF and SDF-1. In results, early spindle-shaped cells (‘early’ EPCs) which were grown at first week of culture were positive for CD31, CD14 and CXCR-4. Cobblestone shaped cells (‘late’ EPC) were in peak growth at second and third weeks of culture and were also positive using above antibodies except CD14. Early EPCs had not expressed mRNA of KDR, vWF and VE-Cadherin by RT-PCR. However, late EPCs expressed high level of mRNA of those endothelial marker genes. Both early and late EPCs expressed mRNA of eNOS. Late EPC produced more nitric oxide and formed more capillary tubes than those of early spindle-shaped cells. Early EPCs were readily migrated by VEGF and SDF-1 compared with those of late EPCs. In conclusions, we have found two different types of EPCs with different biologic properties during HCB ex vivo expansion. These findings may have potential clinical applications for “cell therapy” on vascular injuries (ie, hindlimb ischemia and myocardial infacrtion). Murine models for vascular injuries are being established to test the efficacy of different types of EPCs from HCB in our Lab.

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