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Platelet-activating factor-induced microvascular dysfunction: role of adherent leukocytes
P Kubes1, M Suzuki, D N Granger
1Department of Physiology, Louisiana State University Medical Center, Shreveport 71130.
The American Journal of Physiology
|January 1, 1990
Summary
Platelet-activating factor (PAF) increases fluid and protein leakage in the gut microvasculature. This process, involving leukocyte adhesion, contributes to intestinal injury during inflammation and ischemia.
Area of Science:
- Gastroenterology
- Microcirculation Physiology
- Immunology
Background:
- Platelet-activating factor (PAF) is linked to intestinal injury in conditions like endotoxemia and ischemia-reperfusion.
- The precise effects of PAF on intestinal microvascular exchange remain incompletely understood.
Purpose of the Study:
- To investigate the impact of PAF on intestinal water and protein transport across microvessels.
- To elucidate the role of leukocytes in PAF-mediated microvascular effects.
Main Methods:
- Local intra-arterial infusions of PAF at varying concentrations (4, 20, 40 ng/min) in an animal model.
- Measurement of intestinal transcapillary, lymphatic, and transmucosal water and protein fluxes.
- Assessment of leukocyte adherence to mesenteric venular endothelium and the effect of a specific monoclonal antibody (MoAb IB4).
Main Results:
- PAF administration significantly increased intestinal water and protein fluxes at all tested concentrations.
- PAF elevated venous hematocrit and vascular protein flux, indicating increased capillary leakage.
- PAF promoted leukocyte adherence, and treatment with MoAb IB4 attenuated these PAF-induced microvascular changes.
Conclusions:
- PAF enhances fluid and protein filtration across intestinal capillaries.
- Adherent leukocytes play a partial but significant role in mediating the microvascular effects of PAF in the intestine.