Polymorphonuclear leukocyte-induced vasocontraction and endothelial dysfunction. Role of selectins

Area of Science:

• Cardiovascular Biology
• Immunology
• Cell Adhesion

Background:

• Polymorphonuclear leukocytes (PMNs) contribute to cardiovascular pathologies.
• Selectin adhesion molecules and their ligands are implicated in inflammatory cell recruitment.

Purpose of the Study:

• To investigate the role of P-selectin, L-selectin, and sialyl Lewisx in PMN-induced coronary vasocontraction and endothelial dysfunction.
• To determine if blocking these interactions can prevent PMN-mediated vascular injury.

Main Methods:

• Cat coronary artery rings were stimulated with thrombin or hydrogen peroxide.
• Autologous PMNs were added, and vasocontraction was measured.
• The effects of anti-P-selectin, anti-L-selectin antibodies, and a sialyl Lewisx-containing oligosaccharide were assessed.
• Endothelial function was evaluated via acetylcholine-induced relaxation.

Main Results:

• PMNs induced significant vasocontraction and endothelial dysfunction in stimulated coronary rings.
• Pretreatment with anti-selectin antibodies or sialyl Lewisx-containing oligosaccharide attenuated PMN-induced vasocontraction and endothelial dysfunction.
• PMN adherence to the endothelium was also reduced by these blocking agents.
• Vascular smooth muscle function remained unaffected.

Conclusions:

• PMN-endothelial interactions mediated by P-selectin, L-selectin, and sialyl Lewisx play a critical role in coronary vasocontraction and endothelial dysfunction.
• These mechanisms may contribute to early endothelial dysfunction following ischemia-reperfusion injury.