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Thrombogenicity of polysaccharide-coated surfaces
Jeffrey F W Keuren1, Simone J H Wielders, George M Willems
1Department of Biochemistry, Maastricht University, P.O. Box 616, 6200 MD, Maastricht, The Netherlands.
Biomaterials
|March 5, 2003
Summary
Heparin-coated artificial surfaces significantly reduce thrombin generation in blood. Standard protein adsorption and platelet adhesion tests do not accurately predict the reduced thrombogenicity of these surfaces.
Area of Science:
- Biomaterials Science
- Surface Chemistry
- Hemostasis
Background:
- Heparinization of artificial surfaces is known to reduce thrombogenicity.
- The precise mechanisms by which immobilized heparin mitigates thrombogenicity remain unclear.
- Understanding these mechanisms is crucial for developing safer medical devices.
Purpose of the Study:
- To investigate the mechanisms underlying heparin's antithrombotic effect on artificial surfaces.
- To compare heparin, alginic acid, and chondroitin-6-sulphate coatings regarding protein adsorption, platelet adhesion, and thrombin generation.
- To evaluate the suitability of protein adsorption and platelet adhesion assays for assessing surface thrombogenicity.
Main Methods:
- Coating artificial surfaces with heparin, alginic acid, and chondroitin-6-sulphate.
- Assessing protein adsorption using purified proteins and flowing plasma.
- Evaluating platelet adhesion from flowing whole blood.
- Measuring thrombin generation potential on coated and uncoated surfaces.
Main Results:
- Heparin-coated surfaces showed higher binding capacity for purified proteins compared to alginic acid and chondroitin sulphate.
- Only heparinized surfaces adsorbed significant antithrombin from flowing plasma; fibrinogen adsorption was negligible on all tested surfaces.
- No platelet adhesion was observed on any coated surface under flowing whole blood conditions.
- Heparinized surfaces demonstrated virtually no thrombin generation, while alginic acid and chondroitin sulphate showed marked reductions compared to uncoated surfaces.
Conclusions:
- Protein adsorption and platelet adhesion assays using anticoagulated blood are unreliable for assessing the thrombogenicity of coated artificial surfaces.
- Heparinized surfaces effectively inhibit thrombin generation, indicating a superior antithrombotic effect.
- The study highlights the importance of direct thrombin generation measurements for evaluating the performance of antithrombotic coatings.