Reduction of cardiac injury in DCD hearts with prolonged ischemic period: Role of MPTP opening and calpain activation

减少缺血期延长的 DCD 心脏的心脏损伤：MPTP 打开和钙蛋白酶激活的作用

• 批准号: 10368400
• 负责人: Mohammed Quader
• 金额: --
• 依托单位: VA VETERANS ADMINISTRATION HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10368400
• 关键词: Affect; Autologous Transplantation; Brain Death; Brain Injuries; CASP1 gene; Calcium; Calpain; Cardiac; Cardiac Death; Cause of Death; Cell Death; Cessation of life; Clinical; Combined Modality Therapy; Coupling; Cyclosporine; Cytosol; Development; Electron Transport; Enzymes; Evaluation; Family suidae; Funding; Generations; Goals; Heart; Heart Injuries; Heart Transplantation; Heart failure; Heterotopic Transplantation; Impairment; In Situ; Incidence; Individual; Inflammation; Injury; Intervention; Ischemia; Kidney; Kidney Transplantation; Lead; Life; Liver; Lung; Mediating; Mediator of activation protein; Metabolism; Mitochondria; Modeling; Muscle Cells; Myocardial Ischemia; Myocardial dysfunction; Myocardium; Organ; Patients; Peptide Hydrolases; Persons; Pharmacology; Play; Process; Protocols documentation; Rattus; Reactive Oxygen Species; Reperfusion Injury; Reperfusion Therapy; Research; Risk; Role; Savings; Solid; Source; Spectrin; Structural Protein; Testing; Time; Translations; Transplantation; Veterans; Warm Ischemia; Work; base; effectiveness study; experience; experimental study; follow-up; graft dysfunction; graft function; heart function; improved; inhibitor; junctophilin; liver transplantation; mechanical circulatory support; mitochondrial dysfunction; mitochondrial permeability transition pore; myocardial injury; novel; porcine model; prevent; protective effect

Patients with end-stage heart failure (HF) require mechanical circulatory support, and if eligible, heart transplantation (HTx). The supply of donor hearts has reached a plateau since the only current source of donor hearts consists of patients with irreversible complete brain damage (donation after brain death, DBD). However, the number of eligible HT recipients increased exponentially. Unfortunately, due to this demand-supply mismatch, up to 20% of patients die while listed for HTx. Thus, there is an urgent need to expand the heart donor pool. A potential new source of such donor hearts is from DCD (donation after circulatory death) donors. DCD donors have increased the transplantation rates of solid organs, including liver, lungs and kidney, by 50%. Unfortunately, DCD protocol induces a sustained warm ischemic time that damages the myocardium precluding its use for clinical transplantation. Thus, the ischemia (ISC) from DCD protocol, the potential myocardial injury from storage, and reperfusion (REP) associated injury combine to represent additional risks to exacerbate injury in the DCD heart, precluding their routine use in clinical transplantation. A limited number of HTx are performed utilizing DCD hearts under strict protocol with very short ischemia times (<20 minutes). Extending the acceptable ischemia time (35 minutes) will allow significant additional DCD hearts to be utilized for HTx. Although the warm ISC is inevitable in DCD hearts, REP injury can be decreased through interventions applied at the onset of REP. We propose that the development of new strategies to prevent REP injury will reduce damage to the DCD heart. Mitochondria are critical targets and mediators of cardiac injury during REP. Mitochondrial permeability transition pore (MPTP) opening is considered a final step to induce cell death during ISC-REP. Since MPTP opening predominantly occurs during REP, there is a window of opportunity to decrease MPTP opening by applying intervention at the onset of REP. Cyclosporine A (CyA) is a classic MPTP inhibitor that decreases cardiac injury in hearts following ISC-REP. We propose that administration of the CyA at the onset of REP can reduce cardiac injury in the DCD hearts. Calpain1 and 2 (CPN1/2) are calcium-dependent proteases that are activated during ISC-REP. Activation of CPN1/2 impairs cardiac function by degrading structural proteins, including spectrin and junctophilin-2 (JPH2). Activation of CPN1/2 also contributes to mitochondrial dysfunction during ISC-REP. In addition, activation of CPN1/2 increases inflammation by cleaving and activating caspase-1. Therefore, we will test if the administration of CPN1/2 inhibitor (MDL-28170, MDL) can decrease cardiac injury in DCD hearts. We will further test if the combined treatment with CyA and MDL can provide additional protection compared to individual CyA or MDL treatment in DCD hearts, especially with a longer ischemia period. Aim 1 will evaluate the MPTP opening and CPN1/2 activation in rat DCD hearts, especially with a longer period of ISC. We will further study if REP after DCD hearts with a prolonged period of ISC further increases MPTP opening and CPN1/2 activation. Aim 2 will study the effectiveness of CyA or MDL treatment in decreasing cardiac injury in DCD hearts individually and in combination with a prolonged period of ISC. Aim 3 will study the protective effect of CyA or MDL in heterotopic transplanted rat hearts with a longer duration of follow-up (2 weeks). To establish the translation potential of our work, we will test the benefits of CyA and MDL in a DCD pig heart auto- transplantation model. Our planned experiments and the anticipated results will increase DCD hearts' availability for HTx even with longer periods of ISC-REP. Using an integrated treatment approach as proposed, we aim to move towards using DCD hearts for clinical transplantation.

终末期心力衰竭（HF）患者需要机械循环支持，如果符合条件， 移植（HTx）。由于目前唯一的供体来源， 心脏由不可逆的完全脑损伤（脑死亡后捐赠，DBD）患者组成。然而，在这方面， 符合条件的HT接受者的数量呈指数级增长。不幸的是，由于这种需求-供应 不匹配，高达20%的患者在列出HTx时死亡。因此，迫切需要扩大心脏供体 池这种供体心脏的潜在新来源是来自DCD（循环死亡后的捐赠）供体。DCD 捐赠者使包括肝，肺和肾在内的实体器官的移植率提高了50%。 不幸的是，DCD方案诱导了持续的热缺血时间，这损害了心肌， 其用于临床移植。因此，DCD方案的缺血（ISC），潜在的心肌损伤 储存和再灌注（REP）相关损伤联合收割机共同代表了加重损伤的额外风险 在DCD心脏中，排除了它们在临床移植中的常规使用。执行有限数量的HTx 在严格的方案下使用DCD心脏，缺血时间非常短（<20分钟）。扩展可接受的 缺血时间（35分钟）将允许显著额外的DCD心脏用于HTx。虽然温暖 ISC在DCD心脏中是不可避免的，REP损伤可以通过在发作时应用的干预来减少。 众议员我们认为，制定新的策略来预防REP损伤将减少对DCD的损害 心线粒体是REP过程中心脏损伤的关键靶点和介质。 转换孔（MPTP）开放被认为是ISC-REP期间诱导细胞死亡的最后一步。 开放主要发生在REP期间，有机会通过以下方式降低MPTP开放 环孢素A（CyA）是一种经典的MPTP抑制剂， ISC-REP后心脏的心脏损伤。我们建议在REP开始时给予CyA， 减少DCD心脏的心脏损伤。钙蛋白酶1和2（CPN 1/2）是钙依赖性蛋白酶， CPN 1/2的激活通过降解结构蛋白损害心脏功能， 包括血影蛋白和嗜连接蛋白-2（JPH 2）。CPN 1/2的激活也有助于线粒体功能障碍 此外，CPN 1/2的活化通过切割和活化半胱天冬酶-1而增加炎症。 因此，我们将测试CPN 1/2抑制剂（MDL-28170，MDL）的施用是否可以减少心脏损伤 在DCD的心中。我们将进一步测试CyA和MDL的联合治疗是否可以提供额外的保护 与单独CyA或MDL治疗DCD心脏相比，尤其是在缺血时间较长的情况下。要求1 将评估大鼠DCD心脏中MPTP开放和CPN 1/2激活，特别是具有较长时间的ISC。 我们将进一步研究长时间ISC的DCD心脏后REP是否进一步增加MPTP开放 和CPN 1/2激活。目的2研究CyA或MDL治疗减轻心肌损伤的有效性 在单独的DCD心脏和与延长的ISC的组合中。目标3将研究保护性 CyA或MDL在异位移植大鼠心脏中的作用，随访时间更长（2周）。到 为了建立我们工作的翻译潜力，我们将在DCD猪心中测试CyA和MDL的益处， 移植模型我们计划的实验和预期的结果将增加DCD心脏的可用性 对于HTx，即使ISC-REP的时间较长。使用所提出的综合治疗方法，我们的目标是 将DCD心脏用于临床移植。