Complement-mediated leukocyte adhesion on poly(etherurethane ureas) under shear stress in vitro

Area of Science:

• Biomaterials Science
• Immunology
• Biophysics

Background:

• Blood-contacting biomaterials can trigger complement activation, leading to leukocyte adhesion.
• Biomaterial formulation and fluid shear stress are potential modulators of this process.

Purpose of the Study:

• To investigate how biomaterial formulation (with/without Santowhite antioxidant) and fluid shear stress affect complement activation and leukocyte adhesion.
• To determine the roles of C3, fibronectin, Factor B, and Factor H in these interactions.

Main Methods:

• Testing base poly(etherurethane ureas) with and without Santowhite antioxidant under static and shear stress conditions.
• Quantifying adherent leukocyte densities and assessing cell morphology.
• Measuring adsorption of complement factors (Factor B, Factor H) and serum proteins.
• Depleting C3 and fibronectin from suspension media to assess their role in cell adhesion.

Main Results:

• Leukocyte adhesion decreased with increasing shear stress.
• Santowhite additive significantly reduced leukocyte adhesion under shear stress but not statically.
• Monocytes adhered more than neutrophils under both conditions.
• C3 and fibronectin depletion reduced cell adhesion under shear stress.
• Santowhite increased Factor B adsorption; shear stress increased Factor H adsorption.

Conclusions:

• Leukocyte adhesion to poly(etherurethane urea) is sensitive to shear stress.
• C3 and fibronectin are crucial for maintaining leukocyte adhesion under shear stress.
• Santowhite additive, combined with shear stress, may reduce leukocyte adhesion via increased Factor H adsorption and a lower state of cellular activation.