Can your heart prevent diabetes?
Being overweight or obese is currently deemed the single best predictor of type 2 diabetes. With the prevalence of obesity on the rise, estimates suggest that one in three American adults could have type 2 diabetes by 2050. Weight loss is key to preventing this epidemic. At SBP, scientists are investigating how hormones released by the heart may help the body burn more calories to prevent obesity and type 2 diabetes.
What color is your fat?
All fat is not created equal. Excess weight is held in energy-storing fat cells called white adipose tissue as well as energy-burning fat cells called brown adipose tissue. Increasing a person’s brown fat could improve the risks associated with obesity.
Two compounds released by the heart in response to high blood pressure—human atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP)—have been found to play a direct role in “browning” white adipose tissue. By browning, white fat starts to burn more calories, mimicking what occurs in brown fat. Sheila Collins, Ph.D., professor in the Integrative Metabolism Program and her research team, are investigating how these natriuretic peptides activate fat browning with the goal of tapping into the process to help promote weight loss and prevent diabetes.
In collaboration with Dr. Richard Pratley at the Florida Hospital – SBP Translational Research Institute for Metabolism and Diabetes, the teams are conducting clinical trials with obese and lean volunteers to test whether BNP can increase energy expenditure and improve glucose tolerance. Since recombinant human BNP is an FDA-approved drug prescribed for acute heart failure patients, the costs, and development and approval times for using BNP for these conditions may be reduced.
How does BNP work?
Investigators in Italy almost 20 years ago discovered that binding sites for BNP, called natriuretic peptide receptors (NPRs), were expressed in human adipose tissue. The natriuretic peptide ‘signaling’ receptor, NPRA, binds the natriuretic peptides, while the natriuretic peptide ‘clearance’ receptor, NPRC, removes them from circulation. Since then, several studies have reported that BNP levels are lower in the blood of obese patients compared to their lean counterparts. Additional research suggests BNP can lead to increased release of adiponectin, an insulin-sensitizing hormone produced by fat cells and that low levels of BNP in the bloodstream might contribute to insulin resistance.
According to Collins, “Early studies proposed that increased clearance is responsible for the lower peptide levels observed in obese individuals in comparison to lean individuals; however, there are no definitive studies to actually prove this or not. Important efforts are currently underway to understand how NPRs are regulated and how the peptides can be best used for their fat-burning capacity.”
Dr. Sheila Collins is a professor at Sanford Burnham Prebys Medical Discovery Institute (SBP) in Lake Nona, Fla. and a recipient of an American Diabetes Association research award. Dr. Richard Pratley is a senior investigator at the Florida Hospital – SBP Translational Research Institute, Medical Director of the Florida Hospital Diabetes Institute, and adjunct professor at SBP in Lake Nona. This post was written by Crystal Woodard, Ph.D., a post-doctoral fellow in Dr. Collins’s lab.
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