Abstract
Bone loss with aging results from attenuated and unbalanced bone turnover that has been
associated with a decreased number of bone forming osteoblasts, an increased number of
bone resorbing osteoclasts, and an increased number of adipocytes (fat cells) in the bone
marrow. Osteoblasts and adipocytes are derived from marrow mesenchymal stroma/stem cells
(MSC). The milieu of intracellular and extracellular signals that controls MSC lineage
allocation is diverse. The adipocyte-specific transcription factor
peroxisome proliferator-activated receptor-gamma (PPAR-