Marrow Adipose Tissue and its Interactions with the Skeletal, Hematopoietic, and Immune Systems

Adipocytes were identified in the bone marrow (BM) more than 100 years ago, yet until recently little has been known about their formation, function or interactions with other BM cells. We know now that marrow adipose tissue (MAT) increases with age, and in response to a variety of stressors. BM adipocytes have also been shown to have regulatory roles through their interactions with multiple cell populations within the marrow. Furthermore, recent and ongoing research is uncovering the cellular origin of BM adipocytes, implicating marrow adipose tissue as a distinct adipose depot. This chapter will highlight recent data regarding these areas, and the interaction of MAT with cells in the skeletal, hematopoietic and immune systems.