GENETICALLY ENHANCED CARDIOVASCULAR DEVICES

基因增强心血管设备

• 批准号: 2231053
• 负责人: TIMOTHY SCOTT-BURDEN
• 金额: $ 15.96万
• 依托单位: TEXAS HEART INSTITUTE
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-08-01 至 1998-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2231053
• 关键词: auxiliary heart prosthesis; biomaterial development /preparation; biomaterial interface interaction; cell type; circulatory assist; cow; gene expression; genetic manipulation; genetic regulation; human tissue; nitric oxide; platelet aggregation inhibitors; prostacyclins; protein engineering; smooth muscle; tissue /cell culture; vascular endothelium

An estimated four million people suffer from congestive heart disease in the United States. The annual death rate from this condition is about half a million and the reduction of these numbers is dependent on heart transplant surgery. However the availability of donor hearts is severely limited (+/- 2000/annum) and is unlikely to improve. Patients awaiting transplantation may resort to implantation of a left ventricular assist device (LVAD) since this, not only retards further general, deterioration, but improves cardiovascular performance. This procedure, which was primarily developed as a "bridging" strategy for transplant patients awaiting donor hearts, may become an alternative to new heart transplantation. The performance of LVADs has been marred by episodes of thrombosis, these occur both soon after implantation (within first 48 hr) and at later stages (after 20-30 days), initiation of the latter appears random and unpredictable. In an effort to prevent these life-threatening events we propose to cover the blood-contacting LVAD surfaces with cells genetically engineered to produce prostacyclin and endothelium-derived relaxing factor, identified as NO, two compounds that inhibit platelet aggregation. The enhanced production of prostacyclin will be engineered into autologous saphenous vein endothelial and smooth muscle cells by viral-vector introduction of prostaglandin H synthase (PGHS). NO production will be accomplished by introduction of NO synthase genes into smooth muscle cells. Since high yields of autologous endothelial cells are difficult to obtain, these will be used to cover the Dacron inlet surfaces at the pump-tissue interface. These are the sites of early thrombosis whereas the textured pump surfaces, that become rapidly covered with a fibrin coagulum following implantation, maybe more involved in the initiation of later thromboembolic events. Production of NO by smooth muscle cells covering the textured pump surfaces will prevent both platelet activation (in combination with prostacyclin) and excessive smooth muscle cell proliferation. Activity of NO synthase (NOS), the enzyme responsible for NO production is dependent on a cofactor, tetrahydrobiopterin. De novo synthesis of this factor is regulated GTP cyclohydrolase activity. Introduction of GTP cyclohydrolase genes into smooth muscle cells will ensure full productivity of NOS. The modification of smooth muscle cells to produce prostacyclin and NO constitutively will engender them with anti-coagulant properties that are normally associated with the endothelium and yet their proliferative activity, an apparent disadvantage to the use of myocytes, will be controlled by the production of NO.

估计有400万人患有充血性心脏病 美国。这种情况的年死亡率约为一半 一百万，这些数字的减少取决于心脏 移植手术。但是，捐助者心的可用性严重 有限（+/- 2000/年），不太可能改善。正在等待的患者 移植可能植入左心室辅助 设备（LVAD）以来，不仅会降低一般性的变质， 但是改善了心血管表现。 此过程，那是 主要作为移植患者的“桥接”策略开发 等待捐助者的心，可能会成为新心的替代品 移植。 LVADS的表现受到了情节的破坏 血栓形成，这些都发生在植入后不久（在前48小时内） 在后来的阶段（20-30天后），后者的开始 随机且不可预测。 为了防止这些威胁生命 我们建议用细胞覆盖血液接触的LVAD表面 经过基因工程生产前列环蛋白和内皮衍生的 放松因子，被识别为否，两种抑制血小板的化合物 聚合。前列环蛋白的增强生产将被设计 通过 病毒载体引入前列腺素H合酶（PGHS）。不 生产将通过将无合酶基因引入到 平滑肌细胞。由于自体内皮细胞的高收率是 难以获得，这些将用于覆盖DACRON入口表面 在泵组织接口。这些是早期血栓形成的部位 而纹理的泵表面则迅速覆盖 植入后的纤维蛋白凝结物，可能更多地参与 启动后来的血栓栓塞事件。平滑生产 覆盖纹理泵表面的肌肉细胞将防止 血小板激活（结合前列环蛋白）和过度 平滑肌细胞增殖。无合酶（NOS）的活性， 负责无生产的酶取决于辅因子， 四氢无菌蛋白。该因素的从头综合是受调节的GTP 环氢酶活性。将GTP环氢酶基因引入 平滑肌细胞将确保NOS的全部生产力。修改 平滑肌细胞产生前列环蛋白，没有组成型会 使他们拥有通常相关的抗凝特性 具有内皮和它们的增殖活性，明显 使用肌细胞的缺点将​​由生产控制 否。