Ex vivo expansion of apheresis‐derived peripheral blood hematopoietic progenitors

Abstract

Because the administration of hematopoietic growth factors and the use of stem cell support often fails to alleviate the neutropenic phase induced by cytotoxic drugs, several investigators have attempted to expand ex vivo hematopoietic progenitors for clinical use. These attempts have clearly shown that the cultured cells are functional and can be safely administered to patients, but that the in vivo performance is disappointing and the concept as a whole is not yet clinically useful. The major reasons for these unsuccessful attempts are thought to be cumbersome cell fractionation techniques, contamination, prolonged incubation, and the use of less than ideal cytokine combinations. In response, we have developed a simple procedure for ex vivo expansion of myeloid progenitor cells. In this assay, unfractionated mononuclear cells from apheresis donors are incubated in nonpyrogenic plastic bags for 7 days in the presence of culture medium either containing fetal calf serum or human plasma, granulocyte colony-stimulating factor, and stem cell factor. We have demonstrated that under these conditions the number of colony-forming units (CFU) granulocyte-macrophage (CFU-GM) and of CFU-granulocyte-macrophage-erythroid-megakaryocyte (CFU-GEMM) increased 7- and 9-fold, respectively, by day 7 and the number of burst-forming units-erythroid (BFU-E) increased 2.7-fold by day 5 of culture. Significant increases in the numbers of cells expressing CD34+, CD34+/CD38+, CD34+/CD33+, CD34+/CD15+, and CD34+/CD90+ and significant declines in the numbers of cells expressing CD34+/CD38- and CD19 surface antigens were also observed. The relative numbers of cells expressing T-cell markers and CD56 surface antigen did not change. By using different concentrations of various hematopoietic growth factor combinations, we can increase the number of mature and immature cells of different hematopoietic lineages.

Application of porous glycosaminoglycan‐based scaffolds for expansion of human cord blood stem cells in perfusion culture

“…The successful application of HSC transplant technology is directly dependent on efficient engraftment of HSCs within the transplanted cell population. However, due to limited quantities of HSCs, many investigators have attempted to achieve ex vivo expansion of HSCs 1–8. Although a number of hematopoietic growth factors have been identified, ex vivo expansion of HSCs is hampered by the tendency of these cells to differentiate in response to treatment with cytokines (e.g., stem cell factor (SCF), interleukin‐3, and thrombopoietin).…”

“…However, due to limited quantities of HSCs, many investigators have attempted to achieve ex vivo expansion of HSCs. [1][2][3][4][5][6][7][8] Although a number of hematopoietic growth factors have been identified, ex vivo expansion of HSCs is hampered by the tendency of these cells to differentiate in response to treatment with cytokines (e.g., stem cell factor (SCF), interleukin-3, and thrombopoietin). Selfrenewal, proliferation, and differentiation of HSCs in vivo are controlled by interactions with stromal cells, ECM components, and cytokines in the bone marrow microenvironment.…”