You're probably familiar with white fat – it's the stuff that all-too-easily accumulates around our bellies and thighs. But not all fat is created equal: white fat has a healthier cousin, brown fat, which the body burns easier. Promoting brown fat has been the subject of research for a few years, and now a team from Purdue University has developed a technique to convert white to brown, by loading nanoparticles with an existing drug and injecting them into fat deposits.

The Purdue team made use of a cell signalling pathway called Notch signalling, where one cell controls the gene transcription of its neighbors, which changes what kind of cell that neighbor ultimately becomes. Blocking that signal can prevent certain progenitor cells from becoming white fat cells, and instead turn them into brown fat.

The researchers did this using a drug called Dibenzazepine, which is known to disrupt Notch signalling, and wrapped it in nanoparticles made of a polymer called PLGA. Measuring less than 200 nanometers wide, these particles can be injected into fat deposits where they'll be absorbed by individual fat cells, and once inside, they can release their payload of Dibenzazepine in a very targeted attack.

"We can control the delivery to specific sites in the body, in this case the bad fat or white fat cells," says Meng Deng, co-author of the study. "Once those engineered particles are inside the fat cells, they can slowly release the drug in the cells, potentially limiting the off-target interactions in other tissue in the body and reducing the frequency of dosing."

The researchers tested their system in mice, and found that weekly injections of the nanoparticles into a specific fat deposit increased the amount of brown fat that formed. In turn, that reduced the overall amount of fat in the mice, and improved related health issues, like glucose intolerance and insulin sensitivity.

While this study was conducted in mice, the researchers are hopeful that it could eventually be applied to a human treatment to prevent obesity and reduce the risk of run-on diseases like diabetes.

The research was published in the journal Molecular Therapy.