[Stromal bone marrow cells and the hematopoietic microenvironment]

Stromal clonogenic fibroblasts of the bone marrow possessing osteogenic potential are responsible for hemopoietic bone marrow microenvironment. These cells may be recovered from the bone marrow by cloning in cell cultures; their progeny cells upon retransplantation into the body form new bone marrow organs. Microenvironmental cells are histogenetically independent of hemopoietic cells. In bone marrow cell suspensions prepared by bone marrow tissues trypsinization stromal clonogenic cells are present in greater concentrations than in those prepared by mechanical mincing of the bone marrow tissue. New ectopic bone marrow organs may be created by transplantation of trypsinized suspensions in porous sponges.