Ultrasound image-guided treatment of ischemia-reperfusion injury using argon microbubbles

该提案的关键健康意义涉及超声介导、图像引导、局部治疗 使用回声氩微泡在神经元和心脏模型中的缺血再灌注损伤（IRI） （Armbs）.不存在临床上批准的用于治疗经历缺氧后受损组织的方法 缺血和再灌注损伤，如中风或心脏骤停。稀有气体，如氩气（Ar）和氙气（Xe） 是非常有前途的细胞保护剂，已显示在体外和体内成功治疗急性IRI。 动物模型尽管已经对ESTA进行了更详细的研究，包括在早期的临床试验中， 价格昂贵，难以获得。AR便宜一百倍，而且广泛可用， 优异的有机保护效率。此外，抑制作用的机制取决于其与 细胞膜上的谷氨酸受体，而Ar据报道通过刺激各种内源性 细胞保护信号通路，使其成为更通用的抗凋亡剂。目前的氩治疗时间较长 和全身性的，通过吸入，使其对损伤部位非特异性的，可能降低治疗效果。作为 解决方案，我们建议开发MB（MB）用于治疗气体的局部输送。MB是 由于它们由临床超声引起的非线性振荡而固有地产生回声。治疗气体，如 然而，由于前者的高水溶性，Ar难以在气泡内稳定。该团队已经 最近成功地在小规模生产的稳定，回声，惰性气体MB的优化， MB外壳组成，导致与儿童医院的临床医生进行了富有成效的持续合作。 费城（CHOP）。拟议的研究将通过实施三个具体的 目标。(1)将以>1010 MB/mL的高产率配制1-10 µm ArMB。优化的超声信号 将在流动体模和小鼠模型中通过测量幅度、灌注和 对比的持久性。(2)超声介导气泡释放Ar治疗IRI的疗效观察 将在基于体外细胞培养的模拟氧诱导的神经元和心脏损伤中进行估计 葡萄糖剥夺ArMBs的有效性将通过增强细胞活力、减少caspase 激活和上调磷脂酰肌醇3激酶（PI 3 K-AKT）途径。(3)进一步鼓励 使用ArMB将通过比较它们的IRI处理结果与大量Ar暴露于细胞的结果来识别， 暴露于XeMB。即使谷氨酸受体失活，ArMB活性也会显示出与谷氨酸受体的结合。 ArMB用于多种细胞保护治疗的可行性。PI团队将利用其专业知识， 胶体设计，细胞动力学和超声成像，以精确设计ArMB外壳，并严格 建立这种新的，廉价的代理人在体外的有效性，为团队的长期目标，测试ArMB的 在大型动物模型中对IRI进行非侵入性的图像引导治疗，并将其转化为临床环境。

The key health significance of this proposal involves the ultrasound-mediated, image-guided, localized treatment of ischemia reperfusion injury (IRI) in neuronal and cardiac models using echogenic argon microbubbles (ArMBs). There exist no clinically approved methods for treating damaged tissue after experiencing hypoxic ischemic and reperfusion injuries such as stroke or cardiac arrest. Noble gases like argon (Ar) and xenon (Xe) are highly promising cytoprotective agents that have been shown to successfully treat acute IRI in vitro and in animal models. Whereas Xe has been researched in greater detail including in early clinical trials, it can be prohibitively expensive and difficult to obtain. Ar is a hundred times cheaper and widely available, while exhibiting excellent organoprotective efficiency. Furthermore, the mechanism of Xe action depends on its interaction with glutamate receptors on cell membranes, whereas Ar is reported to work by stimulating various endogenous cellular protecting signaling pathways, making it a more versatile antiapoptotic agent. Current Ar therapy is long and systemic, via inhalation, making it non-specific to the injury site, likely diminishing therapeutic effect. As a solution, we propose the development of MBs (MBs) for localized delivery of the therapeutic gas. MBs are inherently echogenic due to their non-linear oscillations induced by clinical ultrasound. Therapeutic gases such as Ar, however, are difficult to stabilize inside bubbles due to the former's high aqueous solubility. The team has recently succeeded in small-scale production of stable, echogenic, noble gas MBs through optimization of the MB shell composition, leading to a productive, ongoing collaboration with clinicians at the Children's Hospital of Philadelphia (CHOP). The proposed research will be conducted through the implementation of three specific aims. (1) 1-10 µm ArMBs will be formulated at a high yield of >1010 MBs per mL. Ultrasound signal of optimized ArMBs will be investigated in flow phantoms and in a mouse model by measuring the magnitude, perfusion, and persistence of contrast. (2) The therapeutic effect of ultrasound mediated Ar release from bubbles in treating IRI will be estimated in in vitro cell culture-based simulations of neuronal and cardiac injuries induced by oxygen glucose deprivation. The validity of ArMBs will be proved by enhanced cell viability, decrease in caspase activation, and upregulation in the phosphatidylinositol 3 kinase (PI3K-AKT) pathway. (3) Further incentive to use ArMBs will be recognized by comparing their IRI treatment results to that of bulk Ar exposure to cells and exposure to XeMBs. ArMB activity even with the deactivation of glutamate receptors will be shown to cement the feasibility of ArMBs for a variety of cytoprotective treatments. The PI team will leverage their expertise in colloidal design, cellular dynamics, and ultrasound imaging to precisely engineer the ArMB shell and to rigorously establish the validity of this new, inexpensive agent in vitro for the team's long-term goal of testing ArMBs for non-invasive, image guided treatment of IRI in large animal models and translating them to clinical settings.