Abstract: The present description relates to in vitro methods for culturing hematopoietic stem cells (HSCs) under mild hyperthermia conditions (e.g., between 38° C. and 40° C.) in the presence of a pyrimidoindole derivative agonist of hematopoietic stem cell expansion. The combined use of mild hyperthermia and the pyrimidoindole derivative act synergistically to promote expansion of CD34+ HSCs and/or differentiation into progenitor cells (e.g., megakaryocytic progenitors). The present description also relates to in vitro expanded cell populations of HSCs and/or progenitors, as well as uses thereof in therapy (e.g., transplantation).

Abstract: The present description relates to in vitro methods for culturing hematopoietic stem cells (HSCs) under mild hyperthermia conditions (e.g., between 38° C. and 40° C.) in the presence of a pyrimidoindole derivative agonist of hematopoietic stem cell expansion. The combined use of mild hyperthermia and the pyrimidoindole derivative act synergistically to promote expansion of CD34+ HSCs and/or differentiation into progenitor cells (e.g., megakaryocytic progenitors). The present description also relates to in vitro expanded cell populations of HSCs and/or progenitors, as well as uses thereof in therapy (e.g., transplantation).

Abstract: Based on previous evidence suggesting positive effects of fever on in vivo hematopoiesis, the effect of hyperthermia on the expansion and differentiation of megakaryocytes (MKs) in ex vivo cultures of CB CD34-enriched cells has now been tested. Cells were cultured at 37° C. or 39° C. for 14 days in cytokine conditions optimized for MK development, and analyzed periodically by microscopy, flow cytometry and colony assays. Compared to 37° C., cultures maintained at 39° C. produced much more total cells (5×), MK progenitors (9×) and total MKs (7×), and showed accelerated (3-4 days) and enhanced MK maturation with increased yields of proplatelets and platelets (11.7×). The increased number of CD34+ cells and myeloid progenitors in the 39° C. cultures also suggested a general stimulatory effect of hyperthermia on the expansion of more primitive stem/progenitor cells and of cells of other lineages.

Abstract: Based on previous evidence suggesting positive effects of fever on in vivo hematopoiesis, the effect of hyperthermia on the expansion and differentiation of megakaryocytes (MKs) in ex vivo cultures of CB CD34-enriched cells has now been tested. Cells were cultured at 37° C. or 39° C. for 14 days in cytokine conditions optimized for MK development, and analyzed periodically by microscopy, flow cytometry and colony assays. Compared to 37°?C., cultures maintained at 39° C. produced much more total cells (5X), MK progenitors (9X) and total MKs (7X), and showed accelerated (3-4 days) and enhanced MK maturation with increased yields of proplatelets and platelets (11.7X). The increased number of CD34+ cells and myeloid progenitors in the 39° C. cultures also suggested a general stimulatory effect of hyperthermia on the expansion of more primitive stem/progenitor cells and of cells of other lineages.