THE FUNCTION OF ADIPOCYTES IN THE BONE-MARROW STROMA - AN UPDATE

The adipocyte is the most abundant stromal cell phenotype in adult hum an bone marrow, Four hypotheses may explain their function, First, adi pocytes may serve a passive role, simply occupying excess space in the bone marrow cavity, Second, they may play an active role in systemic lipid metabolism, Third, adipocytes may provide a localized energy res ervoir in the bone marrow, Or fourth, marrow adipocytes may contribute directly to the promotion of hematopoiesis and influence osteogenesis , This article reviews recent findings concerning bone marrow adipocyt e morphology and physiology, the transcriptional and cytokine mechanis ms regulating their differentiation, and the interrelationships existi ng between bone marrow adipocytes, hematopoiesis, and osteogenesis, Ov erall, these data lend support to a ''plastic'' model of bone marrow s tromal cell differentiation; adipocytes may share common functions wit h stromal stem cells, osteoblasts, and hematopoietic supportive cells, (C) 1996 by Elsevier Science Inc.