A research project headed by a faculty member from the Ohio University Heritage College of Osteopathic Medicine, which will explore whether administering a protein that's produced in the body can help prevent obesity and type 2 diabetes, has received $464,145 in funding from the National Institutes of Health.
Chunmin Lo, Ph.D., assistant professor of biomedical sciences, is principal investigator on the project, which will look at the way brown adipose (fat) tissue, or BAT, converts dietary lipids (fatty acids or their derivatives) into heat energy, thus helping to prevent obesity.
A protein that says 'stop eating'
Lo's research will focus on the effects of a protein that naturally occurs in the body. When a person eats a meal high in fat, she explained, one result is that the small intestine secretes a compound called Apolipoprotein A-IV (ApoA-IV), which is known to act as a "satiation protein," telling the body to stop eating.
Chronic consumption of a high-fat diet, however, causes an eventual decrease in BAT thermogenesis (heat production), which can lead to obesity and related medical problems such as diabetes. In addition to its known satiety effect, ApoA-IV also appears to play a role in stimulating BAT thermogenesis; this is the main focus of Lo's research project.
Lo wants to test whether injecting synthetic recombinant ApoA-IV into the bodies of laboratory rodents, some of which have been made obese through a high-fat diet, will increase BAT thermogenesis and energy expenditure, and divert lipids into BAT to maintain this heat production, thus reducing obesity. She also wants to learn more about the role neural circuits may play in the process.
"Our hypothesis is that this protein can increase energy expenditure, increase heat production," she said. "So what we want to know is how this protein could apply to human beings to reduce their body weight."
Looking at the role of nerve activity
Evidence suggests that when ApoA-IV induces heat production in BAT, this process may involve stimulation of neural circuits related to BAT. Thus, the action of ApoA-IV on the nervous system may play a role in inhibiting food intake, as well as in stimulating BAT thermogenesis. The second part of the research will look at this question.
"In the first phase we want to know is it possible that this protein could increase the energy expenditure and breakdown of lipids in brown adipose tissue and generate heat," Lo said. "The second part is we want to know about the neural systems involved."