21 October 2010
Sepsis is a severe infection that can often be fatal, particularly in obese patients. Now, a new study suggests why obese patients are at greater risk and suggests a possible new approach to treatment.
Sepsis is seven times more likely to kill patients who are obese, and one possible reason is that the typical Western diet over-stimulates the body's immune response to the sepsis infection.
To test the theory, Louisiana State University professor Chantal Rivera fed a Western style diet to laboratory mice.
"It was high in saturated fat, high in cholesterol, high in sugar," she said in a telephone interview. "And then [we] exposed them to a model of sepsis and tried to figure out why the inflammatory response in these septic mice that had been fed long-term with this high-fat, high-calorie diet, whether or not the inflammation would be worse — and it was — and then we tried to go after what would make the inflammatory response worse."
In her study, Rivera found a clue in a particular protein that flourished in the mice that got the Western diet.
"And what we found is that, you get this increase in proteins on the cell surface called receptors, and in particular the receptor called toll-like receptor four was enhanced, compared to mice that were fed a normal rodent chow."
And with more receptors in mice — and, presumably, people — on the Western diet, there are more places for the sepsis bacteria to infect. That's a simplification, but Rivera says identifying that receptor could give drug researchers a target for medicines that would reduce the threat of sepsis.
"Sepsis is responsible for more than 100,000 deaths annually in the U.S. alone," Rivera said. "And so, clearly, if we had a target for a drug therapy, it would greatly enhance our capabilities for the medical management of sepsis in these obese patients."
Chantal Rivera's study is published in the BioMed Central journal BMC Physiology.