A team of scientists from North Carolina, in the US, has come up with a patch that slowly and safely releases a drug capable of locally transforming white fat to metabolism-boosting brown fat.
The process of multiplying the number of brown fat cells in the body or somehow boosting their activity has been associated with a lower chance of developing metabolic syndrome and conditions that raise the risk for type 2 diabetes.
White fat greatly affects metabolic risk because white fat cells store energy in the form of a single large oily droplet that is relatively inert. In contrast, brown fat cells contain many smaller droplets as well as energy-demanding mitochondria.
These mitochondria in turn utilise the droplets to generate heat and burn a larger number of calories in the process, hence the interest in inciting the body to produce extra brown fat or rev up existing brown fat.
The easiest way to turn white fat brown is to expose people to low temperatures. However, as researchers learned more about brown fat, they have identified compounds that can activate brown fat without the need for unpleasantly chilling temperatures.
Last year, a research team from Harvard University and MIT engineered one such compound using rosiglitazone, formerly marketed as the blood sugar-lowering drug Avandia, which accumulates in fat tissue when injected intravenously.
Rosiglitazone has been shown to enhance brown fat activation in rats through a mechanism involving the peroxisome proliferator-activated receptor (PPAR), a master regulator of both white and brown fat cells.
In this new study, biomedical scientists at the University of North Carolina partnered with nanotechnology experts across the country and in China to load rosiglitazone into a cell delivery vehicle in the form of a patch in order to release it locally.
The patch has dozens of tiny microneedles on its surface that deliver the drug where it is needed to spur the transformation of energy-storing white fat into calorie-burning brown fat. Using the patch instead of injections may also reduce some of the side effects of the drug.
The research team created nanoparticles containing either rosiglitazone or CL 316243, a drug that is known to produce heat and break down fat in mice via a different mechanism than PPAR.
To test the patches, the researchers attached either an empty patch or one containing either of the two drugs to the lower abdomen of obese mice. The researchers changed the patch every three days for four weeks, then analysed the animals’ fat tissue.
The treated mice had 20 per cent less subcutaneous fat and more beige fat, which behaves a lot like brown fat, under the patch. A higher number of genes associated with brown fat were turned on and they also had lower fasting blood glucose levels.
While these findings need to be replicated in humans first, this new patch technology holds promise to help lower risks of developing metabolic syndrome by reducing the amount of abdominal white fat tissue stores.