FXII contact activation products have an inhibitory effect on αFXIIa

Area of Science:

• Biochemistry
• Materials Science
• Hemostasis

Background:

• The intrinsic pathway of blood coagulation is activated upon contact with foreign surfaces, like biomaterials.
• This contact activation generates enzymes that initiate plasma coagulation.
• Understanding these interactions is crucial for biomaterial development and thrombosis prevention.

Purpose of the Study:

• To investigate the role of surface wettability in Factor XII (FXII) activation and subsequent inhibition of coagulation.
• To determine the effect of prekallikrein on FXII activation products and their inhibitory capacity.
• To elucidate the complex interactions between plasma proteins, material surfaces, and the coagulation cascade.

Main Methods:

• Activation of FXII using hydrophilic and hydrophobic glass beads in buffer solutions.
• Quantification of FXII activation products and their inhibitory effects on exogenous alpha-FXIIa (αFXIIa).
• Assessment of the influence of prekallikrein on FXII activation and inhibition.

Main Results:

• FXII contact activation products suppressed the procoagulant activity of αFXIIa in a concentration-dependent manner.
• Inhibition rates varied with surface wettability, with similar inhibition observed at high αFXIIa concentrations (~39%).
• Prekallikrein increased FXIIa production and modulated inhibitor levels on hydrophilic surfaces, while the combination of activation products and surfaces enhanced inhibition.

Conclusions:

• Biomaterial contact activation generates FXII-derived inhibitors that modulate coagulation.
• Surface wettability and prekallikrein presence significantly influence the inhibitory capacity of FXII activation products.
• These findings deepen our understanding of plasma-material interactions and their impact on the coagulation cascade.