Tumor Necrosis Factor Mediates Hypertriglyceridemia During Thermal Injury in Mice Genetically Susceptible to Lipopolysaccharides

Abstract

A rise in plasma triglycerides has been noted after thermal injury in a number of animal species including humans. In this study we identified a factor, tumor necrosis factor, which was responsible for increased plasma triglycerides during thermal injury that was induced by scalding. Two strains of mice that differed genetically in susceptibility to lipopolysaccharides were used. These were CH3HEB/HeJ (LPS-) and CH3HEB/FeJ (LPS+). A 15% total body surface area was burned; this resulted in an increase of plasma triglycerides of 126% of preburn levels in the LPS+ strain 24 hours after burn injury. No change in triglycerides was noted in the LPS- mice at any time after burn injury. Sera from LPS+ mice at 1 to 2 hours after burn injury was injected into nonburned animals of the same strain; this caused a 62% +/- 5% increase in plasma triglycerides 24 hours after injection. When thermally injured LPS+ mice were injected with anti-tumor necrosis factor-alpha at 1 hour after injury, they did not show a rise in plasma triglycerides at any time between 24 to 72 hours after injury. Hepatic secretion of triglycerides was also measured 1 day after burn; the average secretion of triglycerides was significantly reduced (2.69 +/- 0.36 mg/kg/hr, compared with 3.83 +/- 0.15 mg/kg/hr for the control). We conclude that tumor necrosis factor, a cytokine that inhibits lipoprotein lipase, causes hypertriglyceridemia during thermal injury in spite of a decreased secretion of triglycerides. This is the first report that demonstrates that hypertriglyceridemia that is secondary to thermal injury is induced by tumor necrosis factor.