Leucocyte/endothelium interactions and microvessel permeability: coupled or uncoupled?

Area of Science:

• Immunology
• Vascular Biology
• Inflammation Research

Background:

• Leukocyte adhesion and migration are critical for host defense but can cause tissue injury.
• Anti-adhesion therapies have shown limited success in preventing inflammation-induced vascular dysfunction.
• The mechanisms of leukocyte adhesion differ from those causing microvessel permeability increases.

Purpose of the Study:

• To review emerging evidence on adhesion-uncoupled permeability changes.
• To re-evaluate the relationship between leukocyte/platelet activation and microvessel permeability.
• To propose targeting endothelial activation as a therapeutic strategy.

Main Methods:

• Literature review focusing on recent studies.
• Analysis of temporal and spatial dissociations between adhesion and permeability.
• Synthesis of findings on endothelial activation and platelet-dependent leukocyte recruitment.

Main Results:

• Leukocyte adhesion and emigration are not always coupled to microvessel permeability increases.
• Endothelial activation by inflammatory mediators drives platelet adhesion and leukocyte recruitment.
• Platelet-dependent leukocyte recruitment augments microvessel permeability.

Conclusions:

• Targeting endothelial activation and enhancing endothelial barrier function may be more effective than anti-adhesion therapies.
• Understanding the distinct mechanisms regulating permeability is crucial for developing better treatments.
• Re-evaluating the coupled relationship between inflammatory cell activation and vascular permeability is necessary.