Nanoparticles show promise delivering antiobesity drugs directly into fat tissue.
A recent study used nanoparticles to deliver antiobesity drugs directly into the fat tissue in overweight mice models.
These drugs turn white adipose tissue into brown adipose tissue that burns fat and also stimulates the growth of new blood vessels (angiogenesis) in fat tissue. This helps the nanoparticle target cells and helps in turning white tissue brown.
Researchers created a new way to deliver these drugs so they accumulate in fatty tissues rather than in other parts of the body, according to the study, published in Proceedings of the National Academy of Sciences.
Promoting the growth of new blood vessels can lead to weight loss in the mice models, but these drugs can also be harmful to the rest of the body, as discovered by researchers in previous studies.
In the current study, researchers created the particles with the ability to carry drugs in their hydrophobic cores and bind to the polymer PLGA.
The drug rosiglitazone, which can treat diabetes, and an analog of prostaglandin, were both inserted into the particles. Both of these drugs activate PPAR, which is a cellular receptor that stimulates angiogenesis and the adipose transformation.
The outer shell of the particle was composed of another polymer, PEG, with targeting molecules to guide the particle to the designated area. These molecules will bind to proteins in the lining of blood vessels of surrounding adipose tissue.
Researchers found that obese mice lost about 10% of their body weight and their levels or cholesterol and triglycerides also decreased. These mice showed an increased sensitivity to insulin and did not show any side effects.
The treatment was delivered every other day for 25 days, according to the study. Currently, the particles are injected intravenously and make it suitable for morbidly obese patients who have an increased risk of obesity-related diseases.
"For it to be more broadly applicable for treatment of obesity, we have to come up with easier ways to administer these targeted nanoparticles, such as orally," said study co-author Omid Farokhzad, MD.
Orally administered nanoparticles, however, have difficulties entering the lining of the intestine. Researchers hope to find more specific adipose tissue targets that could lessen the possibility of side effects.
"This is a proof-of-concept approach for selectively targeting the white adipose tissue and 'browning it' to allow the body to burn fat. The technology could then be used with other drug molecules that may be developed or other targets that may come up," Dr Farokhzad concluded.