Improved metabolic responses to burn injury and endotoxaemia with the use of a novel lipid source
Burn injury complicated by endotoxaemia may elicit such severe metabolic stress responses that the resultant acute protein malnutrition contributes to multi-organ failure. Current nutritional support regimens often fail to mitigate against such lean body mass depletion. A novel medium chain triglyceride/fish oil structured lipid (MCT/fish oil) was developed to optimize the nutritional benefits of fat during stress. MCT/fish oil enterally fed for 3 days to rats with a 30% burn improved their nitrogen balance, hepatic and muscle protein synthesis compared to safflower oil (SO) fed controls. The reduced net protein catabolism was similar to published results with conventional structured lipids, but uniquely MCT/fish oil reduced the rise in total energy expenditure. Guinea pigs were next pair fed for 6 weeks with MCT/fish oil or SO and then continuously infused with a sublethal dose of Escherichia coli endotoxin. MCT/fish oil feeding produced a significantly higher omega-3/omega- 6 fatty acid ratio in plasma phospholipid of guinea pigs and prevented the severe lactic acidosis of endotoxic shock observed in SO fed animals. It is concluded that short term feeding with MCT/fish oil improved the protein and energy metabolism of burned rats. Long term feeding with MCT/fish oil attenuated the hypoxic response to endotoxic shock and prevented lactic acidosis in guinea pigs. This novel structured lipid may have a significant role in improving the nutritional support of metabolic stress following severe injury.