Vascular graft-associated complement activation and leukocyte adhesion in an artificial circulation

Area of Science:

• Biomaterials Science
• Immunology
• Vascular Surgery

Background:

• Leukocyte adhesion to polymers is common, but interactions with vascular graft materials are understudied.
• Understanding leukocyte-complement interactions is crucial for vascular graft biocompatibility.

Purpose of the Study:

• To investigate complement and leukocyte activation by vascular graft materials using an in vitro perfusion system.
• To compare the responses to expanded polytetrafluoroethylene (ePTFE), Dacron Bionit (DB), and pre-clotted DB with human blood.

Main Methods:

• Utilized an in vitro perfusion system with human blood.
• Evaluated leukocyte concentration changes and surface adhesion via scanning electron microscopy.
• Measured complement activation by quantifying C5a levels.
• Tested materials including ePTFE, DB, and pre-clotted DB.

Main Results:

• All tested materials showed decreased leukocyte concentration and adhesion over time.
• Dacron induced significant leukocyte adhesion, primarily affecting neutrophils and monocytes.
• Dacron-induced adhesion correlated with increased leukocyte adhesiveness and complement activation (C5a elevation).
• Sodium citrate inhibited Dacron-induced leukocyte adhesion by preventing complement activation.
• ePTFE and silicone rubber showed minimal leukocyte or complement activation.

Conclusions:

• Dacron vascular grafts elicit significant complement-associated leukocyte activation and adhesion.
• Complement activation is a key mechanism driving Dacron-induced leukocyte adhesion.
• ePTFE and silicone rubber demonstrate better biocompatibility regarding leukocyte-graft interactions.