The role of damage-associated molecular patterns in perioperative morbidities and mortalities of pediatric congenital heart diseases

项目摘要 虽然先天性心脏病（CHD）的死亡率已大大降低，但新生儿和婴儿 由于多器官损伤/衰竭，接受心脏手术的患者仍然处于发病率和死亡率的高风险中。 在儿童住院患者数据库中，新生儿和婴儿约占所有儿科患者的57 接受先天性心脏病手术，并进行了显着更高的住院死亡率（6.9%）相比， 其他年龄组。描述其器官损伤/功能障碍的原因和机制将提供 一个机会来修改我们的临床方法和开发治疗干预。损伤相关 分子模式（DAMPs）是内源性核，线粒体或胞质分子， 细胞内的生理功能。然而，在组织损伤时，DAMP被释放到血流中 通过受损细胞，并通过中性粒细胞和血小板上的模式识别受体（PRR）识别。DAMPs 可通过诱导全身炎症反应（SIRS）和高凝状态引起器官损伤 导致血栓形成。DAMPs的循环水平与SIRS和多器官损伤相关， 创伤和败血症患者。体外循环相关的缺血再灌注损伤 以及随后的器官损伤/功能障碍已经被很好地描述。在大多数心脏手术病例中， 年龄较大的儿童和成人，心脏和肺以外的器官在CPB期间持续灌注，但在 复杂的新生儿和婴儿手术，在完全循环下进行手术修复并不罕见。 停止或仅对大脑进行局部灌注，表明多个器官可能受到缺血- 再灌注损伤输血可引起器官损伤，新生儿几乎总是需要输血， 婴儿，因为他们的身体尺寸相对于CPB回路的体积较小。我们的初步研究表明， 与Toll样受体（TLR）2/4/9相互作用的DAMP循环水平在CPB分离后升高， 婴儿和新生儿。我们假设：1）在新生儿和婴儿的先天性心脏手术中， DAMP水平与高凝状态（血栓形成）以及更严重的器官损伤/功能障碍相关， 2）DAMPs通过TLRs介导的NETs介导的血栓形成和器官损伤在婴儿中比在成人中更多。在 目的1，我们将通过对Toll样受体特异性DAMP进行分析来验证第一种假设 （TLR）2、TLR 4和TLR 9与DAMP之间的关系，并检查DAMP之间的关系 和全身炎症，中性粒细胞签名，凝血，以及新生儿的术后结局 和接受手术修复的婴儿。在目标2中，我们将使用体外人血测试第二个假设， 以及体内小鼠模型。本提案的目标是：1）建立类型之间的相关性 和DAMP水平和术后器官功能障碍/结局，以及2）确定对 DAMPs包括TLR 2/4/9在年轻时的功能。一旦我们建立了相关性，我们将计划应用一个 干预以减少DAMP负荷或治疗性靶向负责任的PRR以减轻器官损伤。

Project Summary Although the mortality of congenital heart disease (CHD) has been reduced significantly, neonates and infants undergoing cardiac surgery are still at a high risk of morbidity and mortality due to multiple organ injury/failure. In the Kids’ Inpatient Database, neonates and infants occupied about 57% of all the pediatric population undergoing congenital heart surgery and carried significantly higher in-hospital mortality rate (6.9%) compared to other age groups. Delineation of the cause and mechanism of their organ injury/dysfunction would provide an opportunity to modify our clinical approach and develop therapeutic intervention. Damage-associated molecular patterns (DAMPs) are endogenous nuclear, mitochondrial, or cytosolic molecules that have physiological functions inside the cell. However, upon tissue injury, DAMPs are released into the blood stream by injured cells, and recognized by pattern recognition receptors (PRRs) on neutrophils and platelets. DAMPs can cause organ injury by inducing systemic inflammatory responses (SIRS) and hypercoagulable state resulting in thrombosis. The circulating levels of DAMPs correlated to the SIRS and multiple organ injury in patients with trauma and sepsis. Ischemia-reperfusion injury associated with cardiopulmonary bypass (CPB) and subsequent organ injury/dysfunction has been well described. In the majority of cardiac surgical cases for older children and adults, organs other than heart and lung are continuously perfused during CPB, but in complex neonatal and infant surgery, it is not rare to have surgical repair done under complete circulatory arrest or regional perfusion only to the brain, suggesting that multiple organs may be subjected to ischemia- reperfusion injury. Blood transfusion can induce organ injury and is almost always required in neonates and infants due to their small body size relative to the volume of CPB circuit. Our preliminary study showed that the circulating levels of DAMPs interacting with Toll-like receptor (TLR)2/4/9 were elevated after CPB separation in infants and neonates. We hypothesize that 1) in congenital cardiac surgery in neonates and infants, higher DAMP levels are associated with hypercoagulability (thrombosis) as well as greater organ injury/ dysfunction, and 2) DAMPs induce more NETs-mediated thrombosis and organ injury in infants via TLRs that in adults. In Aim 1, we will examine the 1st hypothesis by performing profiling of DAMPs specific to Toll-like receptor (TLR)2, TLR4 and TLR9 and DAMPs for an aggregate of PRRs, and examine the relationship between DAMPs and systemic inflammation, neutrophil signature, coagulation, as well as postoperative outcomes of neonates and infants undergoing surgical repair. In Aim 2, we will test the 2nd hypothesis using human blood in vitro as well as in vivo mouse model. The goals of this proposal are to 1) establish the correlation between the type and levels of DAMPs and postoperative organ dysfunction/ outcomes, and 2) to determine responses to DAMPs including TLR2/4/9 functions in young age. Once we establish the correlation, we will plan to apply an intervention to reduce DAMP loads or therapeutically target responsible PRRs to mitigate organ injury.