Focal delivery of nitro-oleic acid using ultrasound targeted microbubble cavitation for the treatment of microvascular obstruction

随着再灌注治疗的引入，急性心肌梗死的死亡率显著下降，从1980年的20%下降到 2008年为5%，但尽管我们的再灌注时间逐渐减少，但一直处于平稳状态。现在，后MI 慢性心力衰竭(CHF)呈上升趋势，且与梗塞面积直接相关。微血管阻塞(MVO) 这是完全再灌注的主要障碍，限制了心肌挽救。这会导致较低的心肌梗塞后射血 并被认为是导致心梗后心力衰竭的最重要因素。 在他的第一次R01中，PI证明了超声靶向微泡空化(UTMC)治疗 在物理上缓解了MVO，这种现象背后的特定机械机制。而UTMC可能 处理MVO的物理阻塞、相关的炎症和缺血再灌注损伤 残留，并可能对心肌环境造成严重危害。 在此建议应用基于硝基脂肪酸(NFA)的治疗策略，与 UTMC。NFA是内源产生的亲电脂肪酸，其硝基取代基是 在调节多效性抗炎信号反应的过程中起关键作用。目前，NFA 可以安全地在人类身上使用(口服和静脉注射)，并已进入第二阶段临床试验。 然而，没有方法可以集中在特定的病理部位。由于两亲性，NFA 与目前大多数MB组合物中存在的磷脂具有良好的分子间相互作用。 因此，我们打算合成新的硝基脂肪酸MBS(NFABS)，用于UTMC在MVO动物模型中的应用。 结合到MBS中，在破裂时释放其外壳内容物，允许快速和有针对性地释放 在MVO现场。NFAB-UTMC治疗策略的优势包括：(A)快速、靶向递送， (B)最初的NO供体作用，以及(C)急性和慢性炎症反应的多效性调节 在MVO中发现。我们假设通过超声靶向传递的硝基脂肪酸微泡 微泡空化，促进硝基脂肪酸定向输送到微血管部位 并可提高治疗效果。这将在以下具体目标中进行测试： 目的1：合成和表征超声靶向的新型硝基脂肪酸微泡 微气泡空化。体外表征需要分析硝基脂肪酸MBS的化学组成 以及声学行为。 目的2：确定超声靶向硝基脂肪酸微泡空化的疗效 微泡治疗微血管阻塞。这一策略的应用，以及控制 条件，将检验假设，UTMC与NFABS导致增加当地交付和NFA的行动 在健康的啮齿动物后肢模型中，与全身NFA注射(目标2A)进行比较。这一模型还将测试 假设UTMC联合NFAB可以减少MVO的持续时间和严重程度(目标2B)。

With the introduction of reperfusion therapy, mortality from AMI has decreased markedly, from 20% in 1980 to 5% in 2008, but has plateaued despite the fact that our time to reperfusion has progressively declined. Now, post MI chronic heart failure (CHF) is increasing and is directly related to infarct size. Microvascular obstruction (MVO) is a major obstacle to complete reperfusion and limits myocardial salvage. It results in lower post MI ejection fraction and is felt to be the single most important contributor to post MI CHF. In his first R01, the PI demonstrated that ultrasound targeted microbubble cavitation (UTMC) therapy physically relieves MVO and that specific mechanical mechanisms underly this phenomenon. While UTMC may address the physical obstruction of MVO, the associated inflammation and ischemia-reperfusion injury remain and can be significantly deleterious to the myocardial environment. It is proposed herein to apply a nitro-fatty acid (NFA)-based therapeutic strategy, in combination with UTMC. NFA are endogenously-produced electrophilic fatty acids having a nitroalkene substituent that is critical in mediating the modulation of pleiotropic anti-inflammatory signaling responses. Currently, NFA can be safely administered in humans (orally and intravenously) and have advanced to Phase 2 clinical trials. However, there is no method for concentrating at specific sites of pathology. Due to an amphipathic nature, NFA have favorable intermolecular interactions with the phospholipids present in most current MB compositions. Thus, we intend to synthesize novel nitro-fatty acid MBs (NFABs) for use with UTMC in an animal model of MVO. Incorporation into MBs, which release their shell contents when ruptured, allows for rapid and targeted release at the site of MVO. The advantages of a NFAB-UTMC therapeutic strategy, include (a) rapid, targeted delivery, (b) initial NO donor actions, and (c) pleiotropic modulation of both the acute and chronic inflammatory responses found in MVO. We hypothesize that nitro-fatty acid microbubbles, delivered via ultrasound-targeted microbubble cavitation, facilitates the targeted delivery of nitro-fatty acid to sites of microvascular obstruction and can improve therapeutic treatment. This will be tested in the following Specific Aims: Aim 1: Synthesize and characterize novel nitro-fatty acid microbubbles for ultrasound-targeted microbubble cavitation. In vitro characterization entails analysis of nitro-fatty acid MBs chemical composition and acoustic behavior. Aim 2: Determine the efficacy of ultrasound-targeted microbubble cavitation with nitro-fatty acid microbubbles for the treatment of microvascular obstruction. Application of this strategy, along with control conditions, will test the hypothesis that UTMC with NFABs results in increased local delivery and actions of NFA in a healthy rodent hindlimb model, compared against systemic NFA delivery (Aim 2A). This model will also test the hypothesis that UTMC with NFABs can lessen both the duration and severity of MVO (Aim 2B).