Acute and Long-Term Outcome Investigations of Fenofibrate on Severely Burned Patients

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Following severe burn injury in human patients the mitochondrial fat oxygenation capacity is decreased in muscle. This is associated with a corresponding progression in the severity of the resistance to the action of insulin on glucose disposal and protein synthesis and breakdown in muscle, regenera...

Following severe burn injury in human patients the mitochondrial fat oxygenation capacity is decreased in muscle. This is associated with a corresponding progression in the severity of the resistance to the action of insulin on glucose disposal and protein synthesis and breakdown in muscle, regenerating wound and liver. Fatty acids or their active intracellular products ( e.g. Diacylglycerol, acyl- Coenzyme A(CoA) or acylcarnitine) are the direct inhibitors of insulin action, rather than tissue triglycerides(TG) itself. In other words, impaired mitochondrial fatty acid oxygenation is the mechanism that causes altered lipid metabolism that ultimately contributes to insulin resistance. Accumulation of active fatty acid products, such as Diacylglycerol, acyl-CoA or acylcarnitine esters in muscle cells is due to the rate of uptake of plasma free fatty acids(FFA) exceeding the rate of oxygenation within muscle due principally to a reduced capacity of mitochondria to oxidize fatty acids. Decreasing insulin sensitivity in muscle is related to impaired insulin signaling. This will be reflected by increased activity of protein kinase C (PKC). Because PKC is thought to exert its regulatory effect primarily on either tyrosine kinase activity on the insulin receptor or downstream kinase insulin receptor substrate (IRS) phosphorylation, these elements of the insulin signaling cascade will be decreased. In turn, elements of insulin signaling related to the response of muscle glucose (PI3 Kinase) and protein (P70S6k)metabolism will be reduced. The investigators propose that increased tissue PKC activity will be associated with increased tissue concentration of Diacylglycerol, acyl-CoA or acylcarnitine. The investigators hypothesize that the treatment of patients with the peroxisome proliferator-activated receptor (PPAR) alpha antagonist fenofibrate will improve mitochondrial capacity to oxidize fatty acids. Insulin sensitivity in muscle, skin and liver in terms of both glucose and protein metabolism will be improved by fenofibrate treatment.

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