OPENING THE BLOOD BRAIN BARRIER FOR MOLECULAR IMAGING

打开血脑屏障进行分子成像

• 批准号: 7719656
• 负责人: Kullervo Hynynen
• 金额: $ 2.82万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7719656
• 关键词: Acoustics; Animal Model; Animals; Antibodies; Back; Blood; Blood - brain barrier anatomy; Brain; Brain Diseases; Brain Neoplasms; Caliber; Cancer Patient; Charge; Clinical; Compatible; Computer Retrieval of Information on Scientific Projects Database; Contrast Media; Coupling; Depth; Devices; Diagnosis; Disease; Disruption; Distal; Doxorubicin; Doxorubicin Hydrochloride Liposome; ERBB2 gene; Effectiveness; Epidermal Growth Factor Receptor; Fluorometry; Frequencies; Funding; Gadopentetate Dimeglumine; Glioma; Goals; Grant; Hair; Head; Heating; Human; Image; Institution; Length; Lesion; Life; Magnetic Resonance Imaging; Malignant Neoplasms; Measurement; Methods; Microscopy; Microspheres; Molecular; Molecular Weight; Monitor; Monoclonal Antibodies; Mus; Neoplasm Metastasis; Neuraxis; Nude Rats; Oryctolagus cuniculus; Penetration; Plastics; Positioning Attribute; Procedures; Rattus; Research; Research Personnel; Resources; Roche brand of trastuzumab; Signal Transduction; Sonication; Source; Standards of Weights and Measures; System; Techniques; Testing; Therapeutic; Time; Tissues; Tracer; Transducers; Ultrasonography; United States National Institutes of Health; Vascular blood supply; Vendor; Water; Work; base; brain tissue; chemotherapy; clinically relevant; cranium; dopamine D4 receptor; dosage; lipid solubility; malignant breast neoplasm; molecular imaging; molecular size; prevent; research study; size; success; tool; tumor; tumor growth

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The delivery of large molecular agents into the central nervous system (CMS) via the blood supply is often impossible because the blood brain barrier (BBB) protects the brain tissue from foreign molecules. The factors that determine penetration of substances from the blood to the CNS are lipid solubility, molecular size, and charge. The BBB prevents penetration of ionized water-soluble materials with molecular weight greater than 180. Thus most of the potential molecular imaging agents cannot reach the brain tissue via the blood supply. A technique that allows these agents to reach the brain tissue will open the door to new possibilities for the diagnosis and monitoring of brain disorders that currently cannot be performed. Such a technique would also result in a new research tool to investigate brain function and disorders in animal models using molecular imaging. Optimization of ultrasound-induced BBB disruption To optimize the procedure, we will first investigate different acoustic parameters to determine the best values for BBB disruption. In experiments in rabbits, we will vary the ultrasound frequency, burst length, repetition frequency, and sonication duration, and gauge the BBB disruption using MRI contrast agents, or as needed, other tracers. Further, we will investigate different commercially-available ultrasound contrast agents. The goal will be to determine which parameters result in the largest BBB disruption without causing unwanted damage to the brain. At the end of this work, we anticipate that we will have the parameters that will be used clinically. We will also characterize what sized agents we can deliver to the brain using fluorescent microspheres (from a vendor such as Invitrogen, Carlsbad, CA). These spheres can be purchased at different diameters (and excitation and emission wavelengths) and imaged and quantified with fluorescent microscopy. Spheres that are excited or fluoresce at different wavelengths can be injected at the same time, thereby providing quantitative images of the extent of the distribution of different size agents. We will inject the microspheres immediately after sonication and at later times to investigate the time course of the resealing of the BBB. These times will be determined from the experiments in the first aim: we will inject the spheres at the times when the BBB is roughly 25% and 50% closed. From those measurements we can evaluate whether the molecular size of the agent that can be delivered depends on the time after sonication. We will also be able to determine whether the closing of the BBB depends on the size of the tracer or if it closes to all agents at the same time. Finally, we will continue our work investigating methods to monitor the procedure using acoustic emission signals. In our preliminary work, we found that a sharp increase in harmonics of the ultrasound frequency occurred during sonications that resulted in BBB disruption. Based on this work, we will develop an automated system that uses the emission signals in real time to control the ultrasound bursts and we hope to be able to determine online the correct ultrasound intensities to use to maximize the BBB disruption without inducing inertial cavitation. Having such a method to guide the procedure will be important because it is difficult to determine the acoustic intensity when focusing deep into living tissue  especially when the sonications are delivered through the intact skull. Delivery of therapeutics in animal models In this work, we will continue our efforts in delivering therapeutics to the animal brain through the ultrasound-induced BBB disruption. In our preliminary work, we have demonstrated that we can deliver clinically relevant dosages of a chemotherapy agent (liposomal doxorubicin  Doxil¿) to the normal rat brain, and we have demonstrated that we can deliver antibodies (dopamine D4 receptor-targeting antibodies) into the brains of mice. We will test the delivery of Doxil¿ into gliomas inoculated in rat brain. We will compare the growth of these tumors for cases with and without BBB disruption of the tissue surrounding the tumors through serial MRI studies. We will also quantify the amount of doxorubicin delivered to the brain using fluorometry (excitation: 480 nm; emission: 590 nm). In addition, we will investigate the delivery of Herceptin¿, a humanized anti-human epidermal growth-factor receptor 2 (HER2 / c-erbB2) monoclonal antibody that is used clinically used to treat breast cancer patients and has shown great success in controlling local and distal breast cancer lesions. When these cancers metastasize to the brain, however, this effectiveness of this agent has been limited because of the BBB. First, we will demonstrate that we can deliver this antibody into the normal brain in experiments in mice. Next, we will inoculate breast cancer tumors in the brains of nude rats to test the effectiveness of this agent when its delivery is combined with BBB disruption. Methods For the experiments, the transducer will be attached to our MRI-compatible positioning device and submerged in a tank of degassed, deionized water. We currently have systems available for our clinical 1.5 and 3T clinical scanners. In the upcoming year, we will also construct a system for our 4.7T animal magnet as well. The anesthetized animal will be placed on its back on a plastic a tray. Acoustic coupling between the water tank and the animal's head will be achieved with plastic bag filled with water. The hair in the beam path will be removed prior to the experiments. Before the animal is placed on the system, the focal position will be located in the MRI coordinate space by imaging the heating produced by sonications in a tissue-mimicking phantom. Based on this registration, we can accurately target the focus in the brain with an accuracy of ~0.5 mm using anatomical MR images as a guide. BBB opening can be confirmed immediately after sonication using standard MRI contrast agents (such as Magnevist¿, Berlex Inc., Wayne NJ).

该副本是使用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这是调查员的机构。 通过血液供应将大分子剂传递到中枢神经系统（CMS）通常是不可能的，因为血脑屏障（BBB）保护脑组织免受外国分子的侵害。确定物质从血液到中枢神经系统渗透的因素是脂溶性，分子大小和电荷的因素。 BBB防止分子量大于180的电离水溶性材料的渗透。大多数潜在的分子成像剂无法通过血液供应到达脑组织。一种允许这些药物到达脑组织的技术将为诊断和监测目前无法执行的脑部疾病的新可能性打开大门。这种技术还将导致一种新的研究工具，以使用分子成像研究动物模型中的脑功能和疾病。 超声引起的BBB破坏的优化 为了优化该过程，我们将首先研究不同的声学参数，以确定BBB中断的最佳值。在兔子的实验中，我们将改变超声频率，爆发长度，重复频率和社会持续时间，并使用MRI对比剂或根据需要的其他示踪剂来评估BBB的破坏。此外，我们将研究不同的市售超声对比剂。目标是确定哪些参数会导致最大的BBB破坏，而不会对大脑造成不必要的损害。在这项工作结束时，我们预计我们将拥有将在临床上使用的参数。 我们还将使用荧光微球（来自Invitrogen，Carlsbad，CA）的荧光微球（CA）来表征我们可以传递到大脑的大小的药物。这些球体可以在不同的直径（以及兴奋和发射波长）下购买，并用荧光显微镜成像并定量。可以同时注入激发或荧光的球体或荧光的球体，从而提供不同尺寸剂分布程度的定量图像。我们将在社交后和以后的时间后立即注入微球，以研究BBB重新密封的时间过程。这些时间将从第一个目标中的实验中确定：我们将在BBB约25％和50％关闭的时代注入球体。从这些测量值我们可以评估可以传递的药物的分子大小是否取决于社会后的时间。我们还将能够确定BBB的关闭是否取决于示踪剂的大小，还是同时关闭所有代理。 最后，我们将继续我们的工作调查方法，以使用声学信号来监视程序。在我们的初步工作中，我们发现超声频率的谐波在超声频率中发生急剧增加，导致BBB破坏。基于这项工作，我们将开发一个自动化系统，该系统实时使用排放信号来控制超声爆发，我们希望能够在线确定正确的超声强度，以最大程度地使用BBB，而无需引起惯性辐射。使用这种指导过程的方法将很重要，因为在深入生命组织时，很难确定声学强度，尤其是当超声处理通过完整的头骨传递时。 在动物模型中提供治疗 在这项工作中，我们将通过超声引起的BBB破坏来继续努力为动物大脑提供治疗。在我们的初步工作中，我们证明了我们可以将化学疗法剂（脂质体竭曲霉素DOXIL）提供给正常大鼠脑的临床相关剂量，并且我们已经证明我们可以将抗体（多巴胺D4受体受体靶向抗体）输送到小鼠的大脑中。 我们将测试在大鼠脑中接种的胶质瘤中的doxil。我们将通过串行MRI研究对这些肿瘤的肿瘤的生长进行比较。我们还将使用荧光法（激发：480 nm;发射：590 nm）来量化递送到大脑的阿霉素的量。 此外，我们还将调查赫斯蒂素（Herceptin）的递送，赫斯蒂素（Herceptin™）是一种人源化的抗人表皮生长因素受体2（HER2 / C-ERBB2）单克隆抗体，用于治疗乳腺癌患者，并在控制局部和不同的乳腺癌病变方面表现出巨大的成功。但是，当这些癌症转移到大脑时，由于BBB，该药物的这种有效性受到限制。首先，我们将证明我们可以在小鼠实验中将这种抗体输送到正常的大脑中。接下来，我们将接种裸大鼠大脑中的乳腺癌肿瘤，以测试该药物的递送与BBB破坏结合时的有效性。 方法 对于实验，传感器将连接到我们与MRI兼容的定位装置上，并浸入脱气的去离子水罐中。目前，我们有可用于临床1.5和3T临床扫描仪的系统。在接下来的一年中，我们还将为4.7吨动物磁铁构建一个系统。麻醉的动物将放在塑料托盘上的背上。水箱和动物头之间的声音耦合将用充满水的塑料袋来实现。梁路径中的头发将在实验之前去除。在将动物放置在系统上之前，焦点位置将通过对模拟组织中的超声处理产生的加热成像，将焦点位置放置在MRI坐标空间中。基于此注册，使用解剖学MR图像作为指导，我们可以准确地靶向大脑中的焦点。使用标准MRI对比剂（例如Magnevist，Berlex Inc.，Wayne NJ）进行超声处理后，可以立即确认BBB开口。