Most current treatments prescribed for obesity are aimed at reducing food intake by targeting the central nervous system. However, these can have significant psychiatric or cardiovascular side effects, which have resulted in over 80% of these medications being withdrawn from the market.
Dr. Yanchuan Shi, who leads the neuroendocrinology group at the Garvan Institute of Medical Research, in Sydney, Australia, wanted to test a new way of reducing weight gain with a new medication they developed, without affecting the central nervous system. Their research has been published in the latest issue of the journal Nature Communications.
The new medication, called "BIB03304," focuses on a nerve signaling molecule called NPY, which helps many animals, including mice and humans, survive conditions in which food shortages are commonplace. NPY is a metabolism regulator that plays a critical role during states of low energy supply, where it helps store fat as a survival mechanism.
According to a report by the Medical News Today website, the team investigated the effects of BIBO3304 on mice and human fat cells from people with obesity. For seven weeks, the researchers fed mice a high-fat diet, with or without BIBO3304. They found that the mice given the drug gained 40% less weight. This, the team discovered, resulted from increased heat generation in the animals' brown adipose tissue and reduced overall fat mass. The drug blocks a type of cell receptor for NPY called Y1 that is found in fat tissue and other tissues in the body.
Interestingly, the scientists discovered that the fat tissue from both mice and humans with obesity had higher activity of the genes for the Y1 receptor than tissue from individuals with a healthy weight. This may partly explain why losing weight can be so difficult, given that NPY increases food intake and reduces energy output when it binds to Y1.
When the researchers applied BIBO3304 to fat cells from people with obesity, the cells switched on the same genes involved in heat generation as those that had been activated in the mice.
This suggests that the drug, or similar molecules, could work in the same way in people as it does in mice.
