Antithrombogenic surfaces: Characterization and bioactivity of surface immobilized PGE1-heparin conjugate

✍ Scribed by Jacobs, Harvey A. ;Okano, Teruo ;Kim, Sung Wan

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 1024 KB
• Volume: 23
• Category: Article
• ISSN: 0021-9304
• DOI: 10.1002/jbm.820230606

✦ Synopsis

A covalently bonded conjugate of commercial grade heparin and prostaglandin E l (PGE,) was synthesized to prevent both fibrin formation and platelet aggregation during thrombus formation. The PGE,heparin conjugate was immobilized on an imidazole carbamate derivatized sepharose bead surface through hydrophilic spacer groups (diamino-terminated polyethylene oxides). One end of the spacer group was coupled to the derivatized surface through a urethane bond between the amine group of the spacer and the derivatized surface. The free amine group of the immobilized spacers was coupled to a carboxylic group of the PGE,-heparin conjugate through an amide bond. Bioactivity of the immobilized conjugate (heparin activity) was measured in terms of increased clotting times (thrombin time assay) and for the inactivation of Factor Xa. Bioactivity of the immobilized compound (PGE, activity) was analyzed by platelet adhesion and platelet release reactions using C14-5- hydroxytryptamine (5-HT). The conjugate immobilized via the C2 spacer showed the highest incidence of platelet adhesion, 5-HT released and the lowest activity for coagulation factors. In contrast, the 1000 a n d 4000 immobilized s y s t e m s showed a significant reduction in platelet activatior., while having the greatest effect on coagulation factors. The results of these experiments imply that the immobilized conjugate is active in preventing both pathways of thrombus formation, and the efficacy is improved through the use of long-chain hydrophilic spacer groups.