Bernacca G M, Gulbransen M J, Wilkinson R, Wheatley D J
University Department of Cardiac Surgery, Royal Infirmary, Glasgow, UK.
Biomaterials. 1998 Jul;19(13):1151-65. doi: 10.1016/s0142-9612(98)00016-7.
Polyurethanes have proven durable materials for the manufacture of flexible trileaflet heart valves, during in vitro tests. The response of two polyurethanes of differing primary structure to parameters of blood compatibility has now been investigated, using an in vitro test cell. Platelet (beta-thromboglobulin) release, complement (C3a) activation, the activation of free plasma and surface-bound factor XII were studied using fresh, human blood (no anticoagulant) or citrated plasma in control and surface-modified polyurethane. Surface modifications were designed to affect material thrombogenicity and included covalent attachment of heparin, taurine, a platelet membrane glycoprotein fragment, polyethylene oxide (PEO), 3-aminopropyltriethoxysilane, and glucose or glucosamine. Unmodified control polyurethanes caused platelet release and complement activation. High molecular weight (2000 D) polyethylene oxide reduced platelet release slightly but only glucose attachment to the surface produced a significant reduction in platelet activation. All modifications reduced C3 activation compared with controls, but the greatest reduction was achieved with polyethylene oxide attachment or glycosylation. Most surface modifications were more activating of factor XII, both in plasma and on the material surfaces, than the control polyurethanes. Heparin and high molecular weight PEO produced the greatest activation of factor XII in the free plasma form, but low molecular weight PEO and glucosamine produced the greatest activation of surface-bound factor XIIa. The least activating surfaces, affecting both free plasma and surface-bound factor XIIa, were those treated with platelet membrane glycoprotein fragment and glucose. PEO surfaces performed relatively well, compared with controls and most surface modifications. The best overall surface, however, was the glucose-modified surface which was least activating considering all parameters of blood compatibility.
在体外测试中，聚氨酯已被证明是制造柔性三叶心脏瓣膜的耐用材料。现在，使用体外测试细胞研究了两种具有不同一级结构的聚氨酯对血液相容性参数的反应。在对照和表面改性的聚氨酯中，使用新鲜人血（无抗凝剂）或枸橼酸盐血浆研究血小板（β-血小板球蛋白）释放、补体（C3a）激活、游离血浆和表面结合的因子XII的激活。表面改性旨在影响材料的血栓形成性，包括肝素、牛磺酸、血小板膜糖蛋白片段、聚环氧乙烷（PEO）、3-氨丙基三乙氧基硅烷以及葡萄糖或氨基葡萄糖的共价连接。未改性的对照聚氨酯会导致血小板释放和补体激活。高分子量（2000 D）的聚环氧乙烷略微降低了血小板释放，但只有表面附着葡萄糖才显著降低了血小板激活。与对照相比，所有改性都降低了C3激活，但聚环氧乙烷附着或糖基化实现了最大程度的降低。与对照聚氨酯相比，大多数表面改性在血浆和材料表面上对因子XII的激活作用更强。肝素和高分子量的PEO在游离血浆形式下对因子XII的激活作用最大，但低分子量的PEO和氨基葡萄糖对表面结合的因子XIIa的激活作用最大。对游离血浆和表面结合的因子XIIa激活作用最小的表面是用血小板膜糖蛋白片段和葡萄糖处理过的表面。与对照和大多数表面改性相比，PEO表面表现相对较好。然而，综合考虑所有血液相容性参数，最佳的整体表面是葡萄糖改性表面，其激活作用最小。
