The patch uses nanotechnology to increase the body’s metabolism and transform energy-storing white fat into energy-burning brown fat, according to the report released Friday by ACS Nano, a publication of the American Chemical Society. During the four weeks of the study, conducted by Columbia University Medical Center (CUMC) and the University of North Carolina, the mice saw 20 percent reduction in body fat where the patch was applied.
“Many people will no doubt be excited to learn that we may be able to offer a noninvasive alternative to liposuction for reducing love handles,” said study co-author Li Qiang, assistant professor of pathology and cell biology at Columbia University Medical Center in New York.
According to Science Daily, to apply the treatment, the drugs are encased in nanoparticles, which are approximately 250 nanometers (nm) in diameter -- too small to be seen by the naked eye. The nanoparticles are then packed into a centimeter-square skin patch containing dozens of microscopic needles. When applied to skin, the needles painlessly pierce the skin and gradually release the drug from nanoparticles into underlying tissue.
"The nanoparticles were designed to effectively hold the drug and then gradually collapse, releasing it into nearby tissue in a sustained way instead of spreading the drug throughout the body quickly," said Zhen Gu, PhD, patch designer, study co-leader associate professor of joint biomedical engineering at the University of North Carolina at Chapel Hill and North Carolina State University.
The new treatment approach was tested in obese mice by loading the nanoparticles with one of two compounds -- rosiglitazone (Avandia) or beta-adrenergic receptor agonist -- known to promote browning in mice but not in humans. Each mouse was given two patches -- one loaded with drug-containing nanoparticles and another without it -- that were placed on either side of the lower abdomen. New patches were applied every three days for a total of four weeks. Control mice were also given two empty patches.
Mice treated with either of the two drugs had a 20 percent reduction in fat on the treated side compared to the untreated side. They also had significantly lower fasting blood glucose levels than untreated mice. Even in lean mice, the treatment with either of the two drugs increased the animals' oxygen consumption (a measure of overall metabolic activity) by about 20 percent compared to untreated controls.
Genetic analyses revealed that the treated side contained more genes associated with brown fat than on the untreated side, suggesting that the observed metabolic changes and fat reduction were due to an increase in browning in the treated mice.
The patch has not been tested in humans. The researchers are currently studying which drugs, or combination of drugs, work best to promote localized browning and increase overall metabolism.