Endotoxin-induced prostanoid production by the burn wound can cause distant lung dysfunction

Area of Science:

• Biomedical Science
• Physiology
• Toxicology

Background:

• Full-thickness burns are associated with systemic inflammatory responses.
• Endotoxins can trigger inflammatory cascades and organ dysfunction.

Purpose of the Study:

• To investigate if burn tissue in the presence of endotoxin releases prostanoids, specifically thromboxane A2 (TxA2).
• To determine if local TxA2 production in burn tissue can cause distant lung dysfunction.
• To compare this to lung injury from intravenous endotoxin administration.

Main Methods:

• Sheep with full-thickness burns received subeschar injections of Escherichia coli endotoxin.
• Measurements included burn lymph and pulmonary artery TxB2 levels, pulmonary artery pressure, PaO2, and lung lymph flow (QL).
• The effect of ibuprofen on TxA2 production and lung response was assessed.

Main Results:

• Subeschar endotoxin significantly increased burn tissue TxA2 production and pulmonary artery pressure, while decreasing PaO2.
• Lung injury was observed without evidence of increased lung permeability.
• Ibuprofen administration prevented both TxA2 production and lung dysfunction.
• Intravenous endotoxin caused lung TxA2 production and a two-phase lung injury with increased protein permeability.

Conclusions:

• Burn tissue, when exposed to endotoxin, can locally produce TxA2, leading to distant lung dysfunction.
• Circulating endotoxin is not required for this burn-induced lung response.
• The lung is the source of TxA2 during endotoxemia, whereas the burn is the source when endotoxin is applied locally beneath the eschar.