Significance of bone marrow stromal cells in hematopoiesis and hematological disorders.

Bone marrow stromal cells (SC) play a crucial role in sustaining proliferation, differentiation and self-renewal of hematopoietic stem cells. It is quite possible that adherent cell layers derived from bone marrow support hematopoiesis in liquid culture (21). Bone marrow SC consist of various types of cells, with fibroblasts (FB) as one of the main components. In the last several years, many laboratories have performed detailed analyses of the regulatory role of SC in hematopoiesis using long-term liquid cultures and semi-solid colony assays. In this review, the author summarizes and discusses characteristics of SC, especially FB; their hematopoietic stimulatory and inhibitory effects; and their significance in hematological disorders.