Differential endothelial gap junction expression in venous vessels exposed to different hemodynamics

Area of Science:

• Vascular biology
• Biomedical engineering
• Cardiovascular research

Background:

• Vein grafts face significant hemodynamic changes after arterial anastomosis.
• Endothelial gap junction expression in arteries is sensitive to hemodynamic forces.
• Understanding these changes is crucial for vein graft adaptation and function.

Purpose of the Study:

• To investigate endothelial gap junction expression in venous vessels under varying hemodynamic stresses.
• To compare connexin (Cx) expression patterns in native veins versus those exposed to altered blood flow.
• To elucidate the role of hemodynamic forces in regulating gap junction expression in vein grafts.

Main Methods:

• Immunocytochemical analysis of connexin (Cx) expression in rat inferior vena cava (IVC) whole mounts.
• Utilized aortocaval fistula (ACF) and IVC-banded ACF rat models to simulate different hemodynamic conditions.
• Confocal microscopy was employed to quantify gap-junctional spot numbers (GJSNs) and total gap-junctional areas (TGJAs).

Main Results:

• Native vein endothelium showed lower GJSNs and TGJAs for Cx40 and Cx43 compared to thoracic aorta; Cx37 was minimally detected.
• ACF model (high flow, low pressure) increased GJSNs and TGJAs for all Cx types (Cx37, Cx40, Cx43).
• IVC-banded ACF model (high pressure, low flow) markedly increased Cx37 expression, while Cx40 and Cx43 remained unchanged.

Conclusions:

• Endothelial gap junction expression in native veins is lower than in arteries.
• Hemodynamic stresses significantly alter endothelial gap junction expression in veins.
• Specific connexin subtypes (Cx37, Cx40, Cx43) exhibit distinct responses to different hemodynamic environments in venous vessels.