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Alveolar macrophage function is selectively altered after endotoxemia in rats
J W Christman1, S F Petras, M Hacker
1Department of Internal Medicine, University of Vermont, Burlington 05405.
Infection and Immunity
|May 1, 1988
Summary
Gram-negative bacterial endotoxin selectively alters alveolar macrophage functions. This study reveals enhanced adherence and hydrogen peroxide production, alongside reduced chemotaxis, impacting adult respiratory distress syndrome.
Area of Science:
- Immunology
- Cell Biology
- Respiratory Medicine
Background:
- Alveolar macrophages (AMs) are crucial immune cells in the lungs.
- Gram-negative bacterial endotoxin is linked to adult respiratory distress syndrome (ARDS).
- The selective impact of endotoxin on AM functions is not fully understood.
Purpose of the Study:
- To investigate the selective effects of in vivo endotoxin exposure on specific alveolar macrophage functions.
- To determine which AM functions are enhanced, inhibited, or unaffected by endotoxin.
Main Methods:
- Rats were treated with gram-negative bacterial endotoxin (5.0 mg/kg).
- Alveolar macrophages were recovered from control and endotoxin-treated rats.
- Functional assays assessed AM adherence, viability, survival, chemotaxis, hydrogen peroxide production, phagocytosis, and secretion of biological response modifiers.
Main Results:
- Endotoxemia enhanced AM adherence but did not affect cell number or viability.
- AM chemotactic movement decreased by 60%, while hydrogen peroxide production increased by 65%.
- Phagocytosis remained unaffected, but secretion of neutrophil chemotactic activity and interleukin-1 increased significantly.
Conclusions:
- Endotoxemia selectively alters AM functions, enhancing some while inhibiting others.
- These selective functional changes in AMs may play a role in the pathogenesis of ARDS associated with gram-negative sepsis.