The bone marrow adipocyte: a cell with a future

Although bone marrow adipocytes are an essential element of the bone marrow microenvironment, they have attracted little interest. Their number varies considerably in the course of development and in different disorders where hematopoiesis is itself subject to variation, A privileged relationship wa s thus thought to exist between adipocytes and hematopoiesis, and was first considered to be limited to support or provision energy and lipid precurso rs from adipocytes to the hematopoietic cells. Owing to the development of cell culture, we can now consider that the bone marrow adipocyte, through i ts endocrine properties and in particular its ability to secrete leptin, pl ays a direct role in the differentiation and proliferation of hematopoietic progenitors. Moreover, phenotypic conversion may be possible between bone marrow adipocytes and osteoblasts, reflecting the common origin of these tw o cell types. Taking into account these particular properties, the future s hould tell us whether this cell should be considered, beside the white and brown adipocyte, as a third type of adipocyte.