Figure 2. Therapies for obesity and diabetes that target the BAT differentiation and activation pathway.

The development of a fully functional brown adipocyte can be divided into three phases: the multipotent mesenchymal stem cell; the brown preadipocyte; and the mature brown adipocytes. Shown in the upper part of the panel are key hormonal regulators of each phase. There are two principal approaches to utilizing BAT as a therapy for obesity and diabetes. One is the conventional in-vitro pharmaceutical approach of developing hormones or drugs that activate components of the pathway leading from the precursor cells to mature, activated brown adipocytes. The other is a novel ex-vivo strategy whereby progenitor cells are isolated from patients surgically, treated with factors that promote brown adipocyte differentiation, and then transplanted back into the same individuals to establish functional BAT that can be activated to burn off excess calories.