Liver metabolism and energy production in Staphylococcus aureus septic shock in mice

Changes in energy expenditure and fat metabolism in rats infused with interleukin-1

Metabolic alterations related to resting energy expenditure (REE) and fat metabolism have been noted during sepsis, and often depend on the causative agent and the stage and severity of the illness. We studied the effect of IL-1, the protein mediator of the 'acute phase' response during infection, on REE, respiratory quotient (RQ), and fat metabolism in male rats (210 g), who were infused over an 8-h period with (1-14C)-palmitate (PALM), (2-3H)-glycerol (GLY) and either saline or interleukin-1 (IL-1). At 7-8 h post infusion, the IL-1 group showed a significant increase in REE but no change in RQ. The IL-1 group also exhibited a significant decrease in serum free fatty acid (FFA) and an increase in FFA clearance. Free fatty acid flux, %PALM oxidation, serum (GLY), glycerol clearance, and glycerol flux (a measure of lipolytic rate) were not significantly different between the two groups. We conclude that IL-1 can mimic the increase in REE seen during infection; the increase in REE is not due to a selective increase in fat oxidation only, although the unchanged RQ and increased REE suggest that there is a proportional increase in net FFA oxidation.

Mitochondrial function in shock

Studies utilizing animal models of circulatory shock have revealed mitochondrial structural and functional damage in the liver, kidney, and brain. Adenosine triphosphate (ATP) synthesis and calcium transport rates of these mitochondria decline significantly during circulatory shock. The specific enzyme functions affected deleteriously by low flow states are the ATP synthetase, adenine nucleotide translocase, and carrier-mediated calcium transport. Other cellular alterations that possibly are responsible for, or are related to, the shock-induced mitochondrial deterioration are discussed. Differences in the mitochondrial responses to endotoxemia and hyperdynamic sepsis are described. Data are presented on the beneficial effects of early glucocorticoid treatment in prevention of mitochondrial functional deterioration during endotoxemia.