Adipose-derived stromal cells--their utility and potential in bone formation.

Many organs contain connective tissue or stromal cells and these cells play important roles in growth, development and tissue repair. Subcutaneous adipose tissue represents an accessible reservoir for the isolation of human stromal cells. Ex vivo, the adipose tissue-derived human stromal cells can be expanded more than 100-fold. These primary cultures respond to adipogenic agonists by accumulating lipid and expressing adipocyte specific proteins, including leptin and the peroxisome proliferator-activated receptor gamma (PPARgamma). In contrast, when the adipose tissue-derived stromal cells are exposed to osteogenic factors, they display osteoblastic gene markers and mineralize their extracellular matrix. This work demonstrates that subcutaneous adipose tissue is a readily available source of multipotential stromal cells. It is possible that these cells will be used clinically to treat a broad range of orthopedic, rheumatologic and periodontal disorders.