Ex vivo expansion of hemopoietic precursor cells on a sublayer treated with parathyroid hormone

The kinetics of hemopoietic precursor cells was studied in cultures treated with parathyroid hormone in a concentration of 10(-7) M. Long-term culturing of bone marrow with parathyroid hormone did not change the number of mature cells, while the number of precursors forming colonies in semisolid media increased 7-fold and the number of cells forming cobblestone areas on day 28 increased 9-10-fold. After 24 h culturing of bone marrow cells on an irradiated sublayer pretreated with parathyroid hormone for 8 and 12 weeks, the number of early hemopoietic precursor cells forming cobblestone areas on day 28 of culturing increased 2-and 5.5-fold, respectively. The expression of Bmi-1 gene responsible for self-maintenance of stem hemopoietic cells increased in cultures treated with parathyroid hormone. It seems that parathyroid hormone can be used for expansion of hemopoietic stem cells ex vivo, which is essential for their transplantation to patients.