Inhibition of macrophage procoagulant activity with lipids reduces intra-abdominal abscess formation in mice
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1Department of Surgery, University of Michigan, Ann Arbor, USA.
Abstract:
Macrophage procoagulant activity (PCA) has been proposed as a critical element in the formation of intra-abdominal abscesses. We tested the ability of local and systemic lipids (a known PCA inhibitor in vitro) to alter both peritoneal macrophage PCA and mixed Escherichia coli/Bacteroides fragilis intra-abdominal abscess formation in vivo. Lipids given intraperitoneally inhibited measured inducible peritoneal macrophage PCA for 8 h, and, in other animals, significantly decreased the number of abscesses formed and prevented abscesses in 29% of animals. Parallel experiments using subcutaneous intralipids did not show these effects. These results support the hypothesis that macrophage PCA produced locally is critical for intraperitoneal abscess formation.
Insights
Local lipids inhibit macrophage procoagulant activity (PCA), reducing intra-abdominal abscess formation in vivo. This supports the critical role of macrophage PCA in developing these infections.
Area of Science:
- Immunology
- Surgical Infection
Background:
- Macrophage procoagulant activity (PCA) is implicated in intra-abdominal abscess development.
- Lipids are known in vitro inhibitors of PCA.
Purpose of the Study:
- To investigate the effect of local and systemic lipids on peritoneal macrophage PCA.
- To determine if lipids can prevent intra-abdominal abscess formation in vivo.
Main Methods:
- Administered lipids intraperitoneally and subcutaneously in an animal model.
- Measured peritoneal macrophage PCA.
- Assessed abscess formation following inoculation with Escherichia coli and Bacteroides fragilis.
Main Results:
- Intraperitoneal lipids inhibited inducible peritoneal macrophage PCA for 8 hours.
- Intraperitoneal lipids significantly decreased abscess numbers and prevented abscesses in 29% of animals.
- Subcutaneous intralipids did not produce these effects.
Conclusions:
- Local administration of lipids inhibits macrophage PCA in vivo.
- Macrophage PCA generated locally is crucial for the development of intra-abdominal abscesses.
- Targeting macrophage PCA may offer a therapeutic strategy for intra-abdominal infections.