分子イメージングを利用した冠動脈硬化性病変の非侵襲的診断法の開発

应用气泡免疫脂质体分子成像技术和超声心动图检测犬左心耳血栓背景：虽然左心耳血栓的存在被广泛认为会增加房颤患者发生脑梗死的风险，但其形态是无定形的，难以在临床环境中使用常规超声心动图进行检测和组织学评价。脂质体是纳米颗粒，其可以将各种试剂递送到靶组织，例如气泡，并且可以用与靶分子结合的抗体或肽包被。方法：采用反相蒸发囊泡法（REV）和超声破碎法制备RGD肽（Arg-Gly-Asp）包被的免疫泡状脂质体。RGD肽对血栓中大量存在的整合素（αvβ3）具有亲和力。结扎麻醉犬左心耳120分钟（n=4）。在通过超声心动图评估的血栓识别之后，首先在超声心动图观察下静脉注射生理盐水作为对照研究（图A）。注射生理盐水10分钟后，静脉注射免疫泡脂质体。使用超声心动图明确识别出左心耳血栓（图B）。在实验方案结束时采集左心耳样本（图C）。结论：免疫泡脂质体的加入，可使左心耳血栓清晰可辨。免疫泡脂质体超声心动图可提供犬左心耳血栓的诊断信息。靶向分子的气泡脂质体可能是一种新的超声心动图模式。

Molecular imaging using bubble immune-liposomes and echocardiography to detect thrombus in left atrial appendage in canine hearts.Background : Although the presence of thrombus in left atrial appendage was widely known to increase the risk of cerebral infarction in patients with atrial fibrillation, but its morphology was amorphous and has been difficult for the detection and histological evaluation using the conventional echocardiography in the clinical settings. Liposomes are nanoparticles that can deliver various agents to target tissues such as bubble and could be coated with antibody or peptide binding to the target molecule. We investigated whether immune-bubble liposomes could detect the thrombus in left atrial appendage in dogs.Methods and Results : Bubble liposomes coated with RGD peptide(Arg-Gly-Asp) were prepared by reversephase evaporation vesicle(REV) and sonication methods. RGD peptide has an affinity to integrin(αvβ3) which was abundant in the thrombus. We ligated the left atrial appendage of anesthetic dogs for 120 minutes(n=4). After the identification of thrombus evaluated by echocardiography, firstly we intravenously administed saline under the observation of echocardiography as control study(Figure A). After 10 minutes of the infusion of saline, we intravenously administed immune-bubble lipomes into the dogs. Thrombus in left auricular appendage was clearly identified using echocardiography(Figure B.) Left atrial appendage samples were obtained at the end of the experimental protocol(Figure C.) and its histological analysis revealed to be a thrombus.Conclusion : By adding immune-bubble liposomes, thrombus in left atrial appendage can be clearly recognized. Echocardiography using immune-bubble liposomes provide the diagnostic information of the thrombus in left atrial appendage in dogs. Bubble liposomes targeting to the molecule could be a novel echocardiographic modality.