Prevention of polyurethane valve cusp calcification with covalently attached bisphosphonate diethylamino moieties
Prevention of polyurethane valve cusp calcification with covalently attached bisphosphonate diethylamino moieties
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DOI：
10.1002/jbm.a.10896
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发表时间：
2003-08-01
影响因子：
4.9
通讯作者：
Levy, RJ
中科院分区：
文献类型：
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作者：
Alferiev, I;Stachelek, SJ;Levy, RJ
目的：聚氨酯人工瓣膜瓣叶钙化导致主要功能损害。以前，我们表明，聚氨酯心脏瓣膜改性与共价连接的双膦酸酯基团在体内抗钙化。然而，我们还发现聚氨酯表面上的高极性阴离子双膦酸酯基团吸引钠反离子吸附，从而将弹性体的吸水率增加到总重量的20%。在这项研究中，我们解决了增加的吸水性，通过调查的假设，共价连接阳离子二乙氨基基团的双膦酸酯改性的聚氨酯将减少吸水性。因此，我们评估了由这种改性聚合物组成的心脏瓣膜小叶的机械和体内抗钙化特性。研究方法：二乙基氨基和双膦酸酯基团（DBP）附加到聚氨酯Biosspan的硬段使用先前公布的溴烷基化方法。吸水率和双轴机械和单轴破坏测试用于确定DBP改性的聚合物的机械性能。大鼠皮下植入物（60天）和延长（150天）在幼年绵羊单肺小叶置换提供了体内评估的双膦酸盐改性聚氨酯。结果：DBP改性聚氨酯和未改性聚氨酯的吸水率分别为1.86%和2.3%。双轴力学测试表明，DBP改性的聚合物比未改性的对照材料更柔顺，但所有聚合物材料具有相似的单轴失效特性。在大鼠皮下和绵羊循环植入物中，通过扫描电子显微镜评估，DBP改性聚氨酯抗钙化，在人工绵羊瓣叶置换术中完全抑制钙化。结论：DBP聚氨酯具有与未改性聚氨酯相当的物理（吸水性）和生物力学性能，并且可以抵抗血流植入物中的固有心脏瓣膜小叶钙化。(C)2003 Wiley Periodicals，Inc.
Objective: Calcification of polyurethane prosthetic valve leaflets causes a major functional impairment. Previously we showed that polyurethane heart valves modified with covalently linked bisphosphonate groups were resistant to calcification in vivo. However, we also found that the highly polar anionic bisphosphonate groups on the polyurethane surface attracted sodium counter ion adsorption, and thereby increased the elastomer's water absorption to 20% of total weight. In this study we address the increased water absorption by investigating the hypothesis that covalently attaching cationic diethylamino groups to the bisphosphonate-modified polyurethane will reduce water absorption. Thus we evaluated the mechanical and in vivo anticalcification properties of heart-valve leaflets composed of this modified polymer. Methods: Diethylamino and bisphosphonate groups (DBP) were appended to the polyurethane Biospan's hard segment using previously published bromoalkylation methodology. Water absorption and biaxial mechanical and uniaxial failure testing were used to determine the mechanical properties of the DBP-modified polymer. Rat subdermal implants (60 days) and extended (150 days) single pulmonary leaflet replacements in juvenile sheep provided in vivo assessments of the bisphosphonate-modified polyurethane. Results: The water absorption properties of the DBP-modified polymers and unmodified polyurethanes were 1.86 and 2.3 %, respectively. Biaxial mechanical tests showed the DBP-modified polymer was more compliant than the unmodified control material, but all polymeric material had similar uniaxial failure properties. In both rat subdermal and sheep circulatory implants, the DBP-modified polyurethane resisted calcification, as assessed by scanning electron microscopy, with complete calcification inhibition in prosthetic sheep valve leaflet replacements. Conclusion: DBP polyurethane possesses physical (water absorption) and biomechanical properties comparable to unmodified polyurethane and can resist intrinsic heart-valve leaflet calcification in blood-stream implants. (C) 2003 Wiley Periodicals, Inc.