Hematopoiesis with Obesity and Exercise: Role of the Bone Marrow Niche.

Hematopoietic stem and progenitor cells (HSPC), the most primitive cells of the hematopoietic system responsible for maintaining all mature blood cells, display the hallmark characteristics of self-renewal and multi-potent differentiation into mature cell lineages. HSPC activity is directed by the bone marrow niche, a complex environment composed of heterogeneous cell populations that regulate HSPC function through the secretion of a wide array of cytokines and growth factors. Diet induced obesity results in a dramatic remodeling of the bone marrow niche, skewing HSPC function resulting in a compromised immune system. Exercise is a viable treatment option for deficits imposed by obesity and to combat immune dysfunction; however, the impact of exercise on the bone marrow niche is not well defined. This review summarizes the available information on how obesity disrupts the normal bone marrow niche and HSPC function. In addition, we review the limited data available detailing how exercise may be used to combat obesity induced bone marrow dysfunction, and discuss future directions for research in this field.