"We figured out how obesity occurs," says William A. Banks, M.D., professor of geriatrics in the department of internal medicine and professor of pharmacological and physiological science at Saint Louis University School of Medicine. "The next step is coming up with the solution."
The scientists used mice to look at how leptin, a hormone secreted by fat cells that tells us to stop eating, gets into the brain. They found that in obese mice, high triglycerides, a type of fat in the bloodstream, prevents leptin from getting into the brain, where it can do its work in turning off feeding and burning calories.
"High triglycerides are blocking the leptin from getting into the brain. If leptin can't get into the brain, it can't tell you to stop eating," says Banks, who is principal investigator and a staff physician at Veterans Affairs Medical Center in St. Louis.
"This is a big deal. We now know what is keeping leptin from getting to where it needs to do its work."
Paradoxically high triglycerides occur in both fat and starving animals and make the brain think the body's starving so the animal keeps eating, which makes it gain more weight.
"We figured out why the troops aren't getting to the front. There is all of this leptin in the blood but it isn't getting to the brain because triglyerides are impairing the transportation system.
"We feel that we now understand what part of the system is broken - why leptin isn't working. We have a better understanding of why people are becoming obese," Banks says.
The research points scientists to a new direction in solving the obesity epidemic.
"Lowering triglyceride levels may very well be a big part of the answer," Banks says. "This is a reasonable deduction that should be tested."
Contact: Nancy Solomon
Saint Louis University