Assessing vascular permeability and nanobubble extravasation with contrast-enhanced ultrasound imaging

项目总结 在许多慢性炎症性疾病中，血管内皮细胞由于以下原因而变得病理上具有渗透性 血管生成、生长因子和炎症细胞因子的产生(例如组胺， 缓激肽等)。在癌症中，这一过程可以被利用来通过增强的 渗透性和滞留(EPR)效应。然而，基于纳米颗粒的疗法导致了不一致的 结果在患者中。这是由多种因素造成的，其中一个主要因素是肿瘤血管构筑的异质性。 无论是病人之间还是单个肿瘤内。将纳米颗粒输送到肿瘤并进入肿瘤 实质因免疫系统的摄取、无效的边集和低效而变得复杂。 渗出。需要指导以告知临床医生哪些疗法对每个患者可能是最有效的。 有效的指导可以减少医疗费用和药物的负面副作用。一款便宜、安全、 非侵入性的实时成像方法可能能够对血管通透性的程度进行分类 在肿瘤中，一旦得到验证，就可以为患者提供个性化的治疗方案。这样的工具不仅可以用来 适用于肿瘤，但适用于所有涉及病理可渗透血管系统的疾病。考虑到这一目标， 本申请中拟议的研究的目标是致力于开发一种实时方法 基于新型纳米气泡(NB)的对比增强技术评价肿瘤血管通透性 活体超声(CEUS)。该方法将建立在临床上使用的动态CEUS协议的基础上 微泡(MBS)。直径为100-400纳米的NBS已被证明渗入肿瘤。 薄壁组织。在开发这种方法时使用临床超声将确保最终转化为 患者是安全的、成本效益高的、非侵入性的，并且可以广泛获得。为了测试这一目标，目标1实验 将侧重于根据Nb大小确定Nb动态CEU动力学，并与MBS进行比较。它还将确定 流动环境中NBS的动力学参数、边际作用和外渗性 血液和通透性内皮细胞。这些结果将有助于确定渗出的NBS的大小和 在AIM 2中应用于更复杂的体内设置时的内皮通透性程度。AIM 2a将使用 可控通透性水平的鸡胚绒毛尿囊膜(CAM)模型检测NB动态 活体内CEUS参数。在已知渗透率水平的情况下，CAM结果将提供基本信息 用于评估体内通透性的程度。这种方法将应用于不受控制的肿瘤环境 在目标2b中。这项拟议的研究将产生：1)关于造影剂大小如何影响相互作用的新信息 利用红细胞和动态CEUS参数，2)实时分析与肿瘤相关的EPR效应， 产生新的生理数据，以及3)确定病理程度的非侵入性方法 体内通透性。这项建议将提供有关血管渗透性和外渗性的重要知识。 纳米颗粒的潜力，这对改善患者护理至关重要。

PROJECT SUMMARY In many chronic inflammatory diseases, vascular endothelial cells become pathologically permeable due to conditions like angiogenesis and production of growth factors and inflammatory cytokines (e.g. histamine, bradykinin, etc.). In cancer, this process can be exploited for delivery of nanoparticles to tumors via the enhanced permeability and retention (EPR) effect. However, nanoparticle-based therapeutics have led to inconsistent results in patients. This is due to many factors, with a main one being heterogeneous tumor vascular architecture both between patients and within a single tumor. Transport of the nanoparticle to the tumor and into the parenchyma is complicated by uptake by the immune system, ineffective margination, and inefficient extravasation. Guidance is needed to inform clinicians on what therapies may be most effective for each patient. Effective guidance could reduce health-care costs and negative side effects of medication. An inexpensive, safe, non-invasive, and real-time imaging method may be capable of categorizing the extent of vascular permeability in tumors and once validated, personalize therapeutic regimens for patients. Such a tool could be used not only for tumors, but for all diseases involving pathologically permeable vasculature. With this goal in mind, the objective of the proposed research in this application is to work toward development of a real-time method for evaluating vascular permeability over the entire tumor using novel nanobubble (NB)-based contrast-enhanced ultrasound (CEUS) in vivo. This method will build upon dynamic CEUS protocols used clinically with microbubbles (MBs). NBs, which are 100-400 nm in diameter, have been shown to extravasate into the tumor parenchyma. The use of clinical ultrasound in developing this method will ensure that eventual translation to patients is safe, cost-effective, non-invasive, and widely accessible. To test this objective, Aim 1 experiments will focus on identifying NB dynamic CEUS kinetics based on NB size and compared to MBs. It will also identify kinetic parameters, margination, and extravasation of NBs in a flow environment in the presence of human whole blood and permeabilized endothelium. These results will help identify the size of extravasated NBs and the degree of endothelial permeability when applied to a more complicated in vivo setup in Aim 2. Aim 2a will use a chick embryo chorioallantoic membrane (CAM) model with controlled levels of permeability to test NB dynamic CEUS parameters in vivo. With known levels of permeability, the CAM results will provide essential information for assessing the extent of permeability in vivo. This method will be applied to an uncontrolled tumor environment in Aim 2b. This proposed research will yield: 1) new information on how contrast agent size affects interaction with red blood cells and dynamic CEUS parameters, 2) a real-time analysis of the tumor-associated EPR effect, yielding new physiological data, and 3) a non-invasive method for determining the extent of pathological permeability in vivo. This proposal will provide crucial knowledge on vascular permeability and extravasation potential of nanoparticles, which is essential to improve patient care.