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Endothelial, not hemodynamic, differences are responsible for preferential leukocyte rolling in rat mesenteric
1Freie Universität Berlin, Department of Physiology, FRG.
Circulation Research
|October 1, 1991
Summary
Leukocyte rolling, crucial for inflammation, occurs in venules but not arterioles. Hemodynamic factors do not explain this difference, suggesting venular endothelium specialization for leukocyte adhesion.
Area of Science:
- Immunology
- Physiology
- Microcirculation
Background:
- Leukocyte rolling and emigration are key inflammatory processes.
- Leukocyte adhesion predominantly occurs in venules, not arterioles.
- Hydrodynamic flow conditions may influence leukocyte-endothelial interactions.
Purpose of the Study:
- To investigate if hydrodynamic flow differences explain preferential leukocyte rolling in venules.
- To compare leukocyte rolling and adhesion in venules and arterioles under varied flow rates.
Main Methods:
- Controlled variation of wall shear rate (gamma w) in rat mesenteric venules and arterioles (20-37 microns diameter).
- Micro-occlusion techniques used to manipulate flow conditions.
- Quantification of leukocyte-endothelial interactions (rolling) and radial distribution.
Main Results:
- Significantly higher leukocyte rolling in venules (39%) compared to arterioles (0.6%).
- Leukocyte rolling in venules decreased with increasing wall shear rate (gamma w).
- Reduced flow in arterioles did not induce leukocyte rolling, even with prolonged exposure.
Conclusions:
- Hemodynamic factors are not responsible for the differential leukocyte adhesion between venules and arterioles.
- Venular endothelium exhibits specialization supporting leukocyte adhesion during inflammation.
- This specialization likely involves specific endothelial-leukocyte adhesion molecules expressed on venules.