HOMOGENEOUS STROMAL CELL-POPULATION FROM NORMAL HUMAN ADULT BONE-MARROW EXPRESSING ALPHA-SMOOTH MUSCLE ACTIN-FILAMENTS

BACKGROUND: Hematopoietic microenvironment has a crucial role homing a nd regulating precursor cell growth both in physiologic and pathologic conditions. Fibroblast, endothelial cells, macrophages, adipocytes, a nd myoid cells, are the cellular component recognized in human bone ma rrow cultures. The presence of myoid cells in human bone marrow has be en observed during fetal life, whereas during adult life, it is strict ly related to pathologic conditions. EXPERIMENTAL DESIGN: The aim of t his study was to isolate a homogeneous stromal cell population. The mo nonuclear fraction obtained from the vertebral body of living humans w as cultured without hydrocortisone and horse serum to inhibit foam cel l differentiation. RESULTS: The immunocytochemistry and electron micro scopy characterization indicate that the cellular population we isolat ed had an homogeneous ''myoid'' differentiation. Moreover, these cells were able to support blast cell colony formation in vitro. CONCLUSION S: This method allowed the preparation of homogeneous myoid cell cultu res depleted of other bone marrow stromal components. The isolation of a single stromal population is relevant in order to study the functio n of contractile filaments in allowing close-binding interactions with hematopoietic precursor cells.