Hematopoietic cell culture therapies (Part II): clinical aspects and applications

McAdams, Todd A.; Winter, Jane N.; Miller, William M.; Papoutsakis, Eleftherios T.

doi:10.1016/0167-7799(96)10054-8

Cited by 34 publications

(20 citation statements)

References 51 publications

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“…We chose MNCs for this study because of their significant potential for clinical use, which may be equal or greater to that of CD34 + cells (McAdams et al, 1996). In comparing the performance of PB MNCs versus CB MNCs, we noticed that, in general, both types of cells responded similarly to culture pH.…”

Section: Discussionmentioning

confidence: 99%

Variations in culture pH affect the cloning efficiency and differentiation of progenitor cells in ex vivo haemopoiesis

1997

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Summary.Haemopoietic cultures may experience pH variations of as much as 0·5 units depending on culture duration and cell density. Since pH is a potent modulator of cellular proliferation and differentiation, we examined its effects on the performance of both semisolid and liquid haemopoietic cultures. Culture pH was found to have substantial effects both on progenitor cloning efficiency (as measured in liquid cultures) and on progenitor cell differentiation (as measured in methylcellulose cultures). Liquid cultures were conducted with both peripheral blood (PB) mononuclear cells (MNCs) and cord blood (CB) MNCs using growth factor combinations that promote either erythroid expansion (IL-3/IL-6/SCF/ Epo) or granulocyte/macrophage expansion (IL-3/IL-6/SCF/ G-CSF/GM-CSF). Reduced pH was found to have either a positive or neutral effect on the expansion and cloning efficiency of progenitors in ex vivo liquid cultures. Cloning efficiencies of PB BFU-E in the erythroid combination were 9-fold higher at low pH (7·1) when compared to high pH (7·6). A small pH increase of 0·2 units over physiological values consistently produced significant reductions (42-85%) in cloning efficiencies for all cell types and cytokine combinations tested. Methylcellulose cultures conducted using CB MNC and PB MNC indicated that differentiation of CFU-GM into progeny was optimal between pH 7·2 and 7·4. The differentiation of erythroid progenitors (BFU-E) progressively increased as pH was increased from 6·95 (no colonies detected) to 7·4 (maximum colonies detected), to 7·6 (maximum haemoglobin content). Methylcellulose cultures using PB CD34 + cells exhibited similar patterns to the MNC cultures. We conclude that even small variations in pH substantially affected the performance of human haemopoietic cultures. The erythroid lineage was particularly sensitive, with its extent of differentiation increasing with increasing pH. PB progenitors are more sensitive to pH variations than CB progenitors.

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Section: Discussionmentioning

confidence: 99%

Variations in culture pH affect the cloning efficiency and differentiation of progenitor cells in ex vivo haemopoiesis

1997

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“…This, in turn, will require more precise understanding of the conditions required to optimize expansion of the population of interest as well as knowledge of the effects of altered conditions on this endpoint in both small-and large-scale culture systems. Because the utility of hematopoietic stem cell (HSC) transplants is well established in clinical medicine (Aglietta et al, 1998;Hoffman, 1999;McAdams et al, 1996;Srour et al, 1999) and the problems due to inadequate HSC numbers are well defined, we have chosen to focus on ex vivo HSC expansion as an initial process for the analysis of interacting cytokine dose effects on stem cell fate decisions in vitro.…”

Section: Introductionmentioning

confidence: 99%

Common and distinct features of cytokine effects on hematopoietic stem and progenitor cells revealed by dose–response surface analysis

Audet

Miller

Eaves

et al. 2002

Biotech & Bioengineering

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Recent studies have identified thrombopoietin (TPO), flt-3 ligand (FL), Steel factor (SF), and interleukin-11 (IL-11) as cytokines able to stimulate amplification of the most primitive murine hematopoietic cells in vitro. However, dose-response and interaction parameters that predict how to optimize mixtures of these cytokines have not been previously defined. To obtain this information, Sca-1(+)lin(-) and c-kit(+)Sca-1(+)lin(-) adult mouse bone marrow cells were cultured for 10 and 14 days, respectively, in serum-free medium with varying concentrations of these cytokines. Quantitative assays were performed to determine the influences of the cytokine combinations tested on changes in long-term repopulating hematopoietic stem cells (HSCs), in vitro colony-forming cells (CFCs), and total cell numbers. A two-level factorial design was first used to screen the effects of TPO, SF, FL, and IL-11 as well as two different incubation temperatures. IL-11 and SF were found to be the most significant stimulators of murine HSC expansion. More detailed analyses of the effects on c-kit(+)Sca-1(+)lin(-) cells of IL-11, SF, and FL concentrations and their interactions using response surface methodology showed IL-11 to have a maximal stimulatory effect on HSC expansion at 20 ng/mL with higher concentrations being inhibitory. In contrast, not even high concentration saturation of the effects of either SF or FL was observed as the stimulatory effect of both SF and FL increased beyond 300 ng/mL. A negative interaction between SF and FL on HSCs was discovered. Interestingly, a generally similar pattern of cytokine effects was found to influence the 14-day output of CFCs and total cells from the same c-kit(+)Sca-1(+)lin(-) starting cell population. However, compared with HSCs, the cytokine requirements for maximizing the generation of CFCs and total cells were at much lower cytokine doses. From the information provided by the factorial analysis, mathematical models based on Monod kinetics for inhibitory substrates were developed that allow total cell, CFC, and HSC expansion to be predicted as a function of the IL-11, SF, and FL concentrations in terms of more widely recognized parameters. Overall, these methods should also serve as a guide for the future design and testing of other ex vivo stem cell expansion systems.

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“…As evidenced by recent clinical trials (Brugger et al, 1995), ex vivo expanded hematopoietic cells offer great promise for the reconstitution of in vivo hematopoiesis in immunocompromised patients who have undergone chemotherapy. Other potential applications for ex vivo expansion include production of cycling stem and progenitor cells for gene therapy, expansion of dendritic cells for immunotherapy, and production of red blood cells and platelets for transfusions (McAdams et al, 1996b).…”

Section: Introductionmentioning

confidence: 99%

Real-time method for determining the colony-forming cell content of human hematopoietic cell cultures

Collins

Nielsen²,

Wong³

et al. 1997

Biotechnol. Bioeng.

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Hematopoietic cell culture therapies (Part II): clinical aspects and applications

Cited by 34 publications

References 51 publications

Variations in culture pH affect the cloning efficiency and differentiation of progenitor cells in ex vivo haemopoiesis

Variations in culture pH affect the cloning efficiency and differentiation of progenitor cells in ex vivo haemopoiesis

Common and distinct features of cytokine effects on hematopoietic stem and progenitor cells revealed by dose–response surface analysis

Real-time method for determining the colony-forming cell content of human hematopoietic cell cultures

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