Diapedese: Molecular Mechanisms and Regulation

Introduction to Diapedese

• The activation of the vascular endothelium by inflammation or infection leads to the conversion of the endothelium from an anticoagulant to a procoagulant state, which is essential for the immune and inflammatory response, according to the American College of Physicians 1, 2

Endothelial Activation and Leukocyte Capture

• The activated endothelium expresses adhesion molecules such as P-selectin and E-selectin on its luminal surface, which interact with ligands on leukocytes, promoting the initial rolling of leukocytes along the vascular wall, as stated by the European Society of Cardiology 2

Firm Adhesion and Transmigration

• The firm adhesion of leukocytes to the endothelial surface is mediated by the interaction between leukocyte integrins (such as LFA-1) and endothelial adhesion molecules ICAM-1 and VCAM-1, which is a crucial step in the diapedesis process, according to the American Heart Association 2, 3

Clinical Implications

• Excessive diapedesis contributes to tissue injury and organ dysfunction in pathological conditions such as sepsis, highlighting the importance of regulating diapedesis in clinical settings, as noted by the American College of Physicians 1, 2, 4

Neutrophil Recruitment and Endothelial Interactions

Molecular Mechanisms

• The transmigration phase of neutrophil recruitment involves immunoglobulin superfamily members and other adhesion molecules 5

Distinguishing from Other Adhesion Molecules

• N-cadherins are not significantly involved in neutrophil-endothelial interactions during inflammation 6