Substrate Cycling in Energy Metabolism

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DESCRIPTION (provided by applicant): We have previously shown that accumulation of both peripheral and hepatic intracellular triglycerides (TGs) occurs following severe burn injury in both human patients and in a porcine animal model. This accumulation of intracellular lipids is associated in time with the development of insulin resistance both at the liver and in the muscle. Our overriding hypothesis is that accumulation of hepatic TG and related lipids induce hepatic insulin resistance following burn injury. We will use the animal model to further examine the mechanisms responsible for hepatic TG accumulation and the relation of increased hepatic TGs to insulin sensitivity. We will investigate the three aspects of hepatic TG accumulation- TG production, secretion as VLDL, and peripheral VLDL clearance. In particular, we will focus on dietary approaches to stimulating VLDL secretion and clearance and reducing hepatic TG production. Our hypothesis is that a hypocaloric diet coupled with an increased protein intake will decrease hepatic storage of TGs, and thereby improve insulin sensitivity. We propose that this is an interactive effect, meaning that neither the hypocaloric diet nor high protein alone will have the same effect as the combination of the two. We further propose that improved insulin sensitivity will be reflected in improved wound healing, maintenance of lean mass and immune function. Studies will be performed in chronically instrumented pigs using stable isotope tracer approaches to quantify appropriate metabolic parameters. The results from these studies will have direct application in the nutritional care of severely burned or injured patients. PUBLIC HEALTH RELEVANCE: Our overriding hypothesis is that accumulation of hepatic TG and related lipids induce hepatic insulin resistance following burn injury. Our central hypothesis is that a hypocaloric diet coupled with an increased protein intake will decrease hepatic storage of TGs, and thereby improve insulin sensitivity. We further propose that improved insulin sensitivity will be reflected in improved wound healing, maintenance of lean mass and immune function. The results from these studies will have direct application in the nutritional care of severely burned or injured patients.