Nanoparticles Prevent Diet-Induced Obesity in Mice

In humans, the much more prevalent white fat cells store fat, but brown fat cells burn fat. When researchers discovered that white fat can be converted into brown fat in vitro after stimulation by either rosiglitazone or a prostaglandin E₂ analogue (NEJM JW Gen Med Oct 15 2008 and Nature 2008; 454:961), the idea that these molecules could be used to treat or prevent obesity was born. These agents also stimulate angiogenesis and attract the new blood supply that newly created brown fat cells need. But how could the same transformation be achieved in vivo?

A multi-institutional team created nanoparticles with two properties: (1) they contained either rosiglitazone or the prostaglandin E₂ analogue; (2) they adhered selectively to the endotheliu…