Targeting mitochondria in SV heart disease

项目摘要 随着手术技术和围手术期管理的进步，有一种 越来越多的单心室先天性心脏病(SV)患者 活到童年甚至更久。由于长期施加的压力和体积负荷 这些患者仍然处于发展和发展的持续风险中。 心力衰竭的进展。不幸的是，人们对心脏衰竭的原因知之甚少 与衰竭的儿童或成人双室心不同。此外，向心脏的过渡 发生在室性心动过速的心脏衰竭也是不完全理解的。这种缺乏理解的现象 心力衰竭的发病机制是确定有效心力衰竭的主要障碍。 有针对性的治疗。此外，SV的稀有性使其很难进行前瞻性的操作 受控药物研究是在成人心力衰竭人群中常规进行的，因此， 治疗是基于对不同患者群体的临床试验的推断， 轶事经验，或潜在的理论上的感知利益。磷酸二酯酶-5 抑制剂(PDE5i)，如西地那非，就是这种越来越多使用的疗法的一个例子 在现有证据基础有限的SV患者群体中。广为流传，而且公平 在SV患者中不分青红皂白地使用PDE5i的部分原因是一些出版物表明 小系列SV患者的临床结果呈阳性。最近发表的NHLBI燃料 (Fontan udenafil运动纵向评估)试验显示改善了亚极量 400例Fontan患者的运动试验。这些令人鼓舞的研究与我们最近的 心脏衰竭患者PDE5表达和活性增加的研究报告 提示心肌可能是PDE5i的有效靶点。 虽然历史上在SV中使用PDE5i的基本原理是增加肺血流量， 我们假设衰竭的心动过速心肌，特别是线粒体，代表一个 也是PDE5i治疗的靶点。我们的初步数据表明：(1)线粒体 衰竭时功能障碍、sirtuin信号改变和线粒体蛋白乙酰化增加 室性心动过速(SVHF)；(2)线粒体活性氧(ROS)减少。 电子顺磁共振(EPR)检测心力衰竭心排出量 体内携带PDE5i；(3)减少蛋白质乙酰化，改善线粒体功能 PDE5i体外治疗心力衰竭心脏；(4)非心动过速患者线粒体功能受损 失败(SVNF)(原代移植或Norwood标本)用PDE5i体外处理的心脏； (5)原代心肌细胞线粒体功能障碍和ROS增加 通过添加PDE5i或SIRT 3激活剂而改善的SVHF患者血清， 和厚朴酚(HNK)。我们假设线粒体功能障碍参与了心衰的转变。 PDE5i可改善心脏衰竭时的线粒体功能。 依赖的态度。我们建议使用人体组织和心肌细胞模型来 完成建议的实验。这个项目的目的是为了了解过渡 并提供临床前证据，以便更有针对性地使用 优化临床护理和改善结果的目标。

Project Summary With advancements in operative techniques and perioperative management, there is an increasing number of patients with single ventricle congenital heart disease (SV) that are surviving into childhood and beyond. Due to the chronic pressure and volume load placed on the single systemic ventricle, these patients remain at constant risk for the development and progression of cardiac failure. Unfortunately, very little is known about how the failing SV heart differs from the failing pediatric or adult biventricular heart. Additionally, the transition to heart failure that occurs in the SV heart is also incompletely understood. This lack of understanding in the mechanisms underlying SV heart failure are a major hurdle in the identification of effective targeted therapies. In addition, the rarity of SV makes it very difficult to perform prospective controlled drug studies as is routinely done in the adult heart failure population and as a result, treatments are based on extrapolation of clinical trials from different patient populations, anecdotal experience, or potential for theoretic perceived benefit. Phosphodiesterase-5 inhibitors (PDE5i), such as sildenafil, are an example of such a therapy that is increasingly used in the SV patient population with a limited existing evidence-basis. Widespread, and fairly indiscriminate use of PDE5i for SV patients is driven in part by several publications suggesting positive clinical results in small series of SV patients. The recently published NHLBI FUEL (Fontan Udenafil Exercise Longitudinal assessment) trial demonstrated improved submaximal exercise in 400 fontan patients. These encouraging studies combined with our recent publication demonstrating increased PDE5 expression and activity in failing SV hearts suggesting that the myocardium may be a viable target of PDE5i. While historically the rationale for the use of PDE5i in SV is to augment pulmonary blood flow, we hypothesize that the failing SV myocardium, and specifically the mitochondria, represent a target of PDE5i therapy as well. Our preliminary data demonstrate: (1) Mitochondrial dysfunction, altered sirtuin signaling, and increased mitochondrial protein acetylation in failing SV myocardium (SVHF); (2) Decreased mitochondrial reactive oxygen species (ROS) generation detected by Electron Paramagnetic Resonance (EPR) in failing SV hearts treated ex vivo with PDE5i; (3) Decreased protein acetylation and improvement in mitochondrial function in failing SV hearts treated ex vivo with PDE5i; (4) Impaired mitochondria function in SV Non- Failing (SVNF) (primary transplant or Norwood specimens) hearts treated ex vivo with PDE5i; and (5) Mitochondrial dysfunction and increased ROS in primary cardiomyocytes treated with SVHF patient serum, which is improved by the addition of PDE5i or the SIRT 3 activator, honokiol (HNK). We hypothesize that mitochondrial dysfunction is involved in the HF transition of SV hearts, and that PDE5i improves mitochondrial function in failing SV hearts in a sirtuin- dependent manner. We propose the use of human tissue and a cardiomyocyte model to complete the proposed experiments. The purpose of this project is to understand the transition to HF in the SV population and provide pre-clinical evidence to inform more targeted use of, with the goal of optimizing clinical care and improving outcomes.