Endoplasmic reticulum stress-induced hepatic stellate cell apoptosis through calcium-mediated JNK/P38 MAPK and Calpain/Caspase-12 pathways

Since ischemic heart disease (IHD) is a major cause of mortality and heart failure, novel therapeutic strategies are expected to improve the clinical outcomes of patients with acute myocardial infarction. Brief episodes of ischemia/reperfusion performed at the onset of reperfusion can reduce infarct size; a phenomenon termed “ischemic postconditioning.” Extensive research has determined that different autacoids (e.g., adenosine, bradykinin, opioid, etc.) and cytokines, their respective receptors, kinase signaling pathways, and mitochondrial modulation are involved in ischemic conditioning. Modification of these factors by pharmacological agents mimics the cardioprotection by ischemic postconditioning. Here, the potential mechanisms of ischemic postconditioning, the presence of comorbidities, and the possible extrapolation to the clinical setting are reviewed. In the near future, large, multicentered, randomized, placebo-controlled, clinical trials will be required to determine whether pharmacological and/or ischemic postconditioning can improve the clinical outcomes of patients with IHD.     

Phosphomimetic Modulation of eNOS Improves Myocardial Reperfusion and Mimics Cardiac Postconditioning in Mice

Objective

Myocardial infarction resulting from ischemia-reperfusion injury can be reduced by cardiac postconditioning, in which blood flow is restored intermittently prior to full reperfusion. Although key molecular mechanisms and prosurvival pathways involved in postconditioning have been identified, a direct role for eNOS-derived NO in improving regional myocardial perfusion has not been shown. The objective of this study is to measure, with high temporal and spatial resolution, regional myocardial perfusion during ischemia-reperfusion and postconditioning, in order to determine the contribution of regional blood flow effects of NO to infarct size and protection.

Methods and Results

We used myocardial contrast echocardiography to measure regional myocardial blood flow in mice over time. Reperfusion after myocardial ischemia-reperfusion injury is improved by postconditioning, as well as by phosphomimetic eNOS modulation. Knock-in mice expressing a phosphomimetic S1176D form of eNOS showed improved myocardial reperfusion and significantly reduced infarct size. eNOS knock-out mice failed to show cardioprotection from postconditioning. The size of the no-reflow zone following ischemia-reperfusion is substantially reduced by postconditioning and by the phosphomimetic eNOS mutation.

Conclusions and Significance

Using myocardial contrast echocardiography, we show that temporal dynamics of regional myocardial perfusion restoration contribute to reduced infarct size after postconditioning. eNOS has direct effects on myocardial blood flow following ischemia-reperfusion, with reduction in the size of the no-reflow zone. These results have important implications for ongoing clinical trials on cardioprotection, because the degree of protective benefit may be significantly influenced by the regional hemodynamic effects of eNOS-derived NO.     

Myocardial ischemic postconditioning: a brief ischemia causes conversion of resistent reperfusion-induced ventricular fibrillation into the normal rhythm

Brief episodes of myocardial ischemia-reperfusion were shown to be protective against reperfusion injury when used during early reperfusion after a prolonged ischemic episode. This phenomenon has been termed myocardial ischemic postconditioning. In this study, an effect of ischemic postconditioning on persistent reperfusion-induced ventricular fibrillation was studied in the rat isolated heart. 2 minutes of global ischemia on the 15th minute of reperfusion after 30 minutes of regional ischemia effectively abolished the persistent ventricular fibrillation. In non-postconditioned hearts, the ventricular fibrillation continued to the end of reperfusion. The ischemic postconditioning seems to exert a strong antiarrhythmic effect protecting the heart against persistent reperfusion-induced ventricular tachyarrhythmias.     

心肺复苏后脑缺血再灌注损伤治疗理念及相关动物模型研究进展

心肺复苏后脑缺血再灌注损伤是一个复杂的病理生理变化过程,由多种损伤机制共同参与。自心肺复苏后系统性综合治疗和亚低温治疗在临床上广泛应用后,目前已有多种治疗理念在不同的动物实验和动物模型基础上被提出,包括缺血预处理、药物预处理、缺血后处理、和药物后处理,而后吸入麻醉药对心肺复苏后脑缺血再灌注损伤的保护作用受到了人们的重视,而七氟烷后处理已经成为目前研究的热点之一。为了指导临床上的心肺复苏,人们一直在利用不同动物模型,探究不同保护方法,寻找有效的脑保护药物。而各种治疗理念的提出均是建立在动物实验和动物模型的基础上,窒息性心肺复苏模型模拟围术期气道梗阻,能较贴切的复制临床上由窒息引起的心肺复苏后脑损伤,对将来指导临床复苏具有重大意义。     

缺血后处理内源性心脏保护的研究进展

再灌注疗法是临床治疗心肌缺血最有效的措施,但会引起再灌注损伤,调动机体内源性保护机制可以减轻再灌注损伤,保护缺血心肌。缺血预处理（ischemic preconditioning,IPC）和后处理（ischemic postconditioning,I-postC）是缺血心脏有效的内源性保护现象,可以减轻缺血再灌注（ischemia／reperfusion,I／R）后心肌坏死与心肌功能障碍,减少恶性心律失常的发生。内源性心脏保护的机制主要是通过诱导触发因子释放,经多条细胞内信号转导途径的介导,作用于多种效应器,影响氧自由基产生、钙超载等I／R损伤的关键环节而发挥心肌细胞保护作用。特别是可以在缺血后实施的I-postC具有良好的临床应用前景。本文以I-postC为重点综述内源性心脏保护作用、机制及其临床应用现状。     

Involvement of CCR-2 chemokine receptor activation in ischemic preconditioning and postconditioning of brain in mice

The present study has been designed to investigate the potential role of CCR-2 chemokine receptor in ischemic preconditioning as well as postconditioning induced reversal of ischemia-reperfusion injury in mouse brain. Bilateral carotid artery occlusion of 17min followed by reperfusion for 24h was employed in present study to produce ischemia and reperfusion induced cerebral injury in mice. Cerebral infarct size was measured using triphenyltetrazolium chloride staining. Memory was evaluated using elevated plus-maze test and Morris water maze test. Rota rod test was employed to assess motor incoordination. Bilateral carotid artery occlusion followed by reperfusion produced cerebral infarction and impaired memory and motor co-ordination. Three preceding episodes of bilateral carotid artery occlusion for 1min and reperfusion of 1min were employed to elicit ischemic preconditioning of brain, while three episodes of bilateral carotid artery occlusion for 10s and reperfusion of 10s immediately after the completion of were employed to elicit ischemic postconditioning of brain. Both prior ischemic preconditioning as well as ischemic postconditioning immediately after global cerebral ischemia prevented markedly ischemia-reperfusion-induced cerebral injury as measured in terms of infarct size, loss of memory and motor coordination. RS 102895, a selective CCR-2 chemokine receptor antagonist, attenuated the neuroprotective effect of both the ischemic preconditioning as well as postconditioning. It is concluded that the neuroprotective effect of both ischemic preconditioning as well as ischemic postconditioning may involve the activation of CCR-2 chemokine receptors.     

High cholesterol diet effects on ischemia-reperfusion injury of the heart

Ischemic heart disease is the leading cause of morbi-mortality in developed countries. Both ischemia-reperfusion injury and mechanisms of cardioprotection have been studied for more than 50?years. It is known that the physiopathological mechanism of myocardial ischemia involves several factors that are closely related to its development, of which hypercholesterolemia is one of the main ones. Therefore, the objective of this review was to elucidate the effects of a high-cholesterol diet on normal ventricular function and ischemia-reperfusion injury associated phenomenon such as post-ischemic ventricular dysfunction (stunned myocardium). Although there exist many studies considering several aspects of this physiopathological entity, the majority were carried out on normal animals. Thus, experiments carried out on hypercholesterolemic models are controversial, in particular those evaluating different mechanisms of cardioprotection such as ischemic preconditioning and postconditioning, and cardioprotection granted by drugs such as statins, which apart from exerting a lipid-lowering effect, exert pleiotropic effects providing cardioprotection against ischemia-reperfusion injury. These controversial results concerning the mechanisms of cardioprotection vary according to quality, composition, and time of administration of the high-cholesterol diet, as well as the species used in each experiment. Thus, to compare the results it is necessary to take all of these variables into account, since they can change the obtained results.     

How to use the paradigm of ischemic preconditioning to protect the heart?

Ischemic preconditioning affords the most powerful protection to a heart submitted to a prolonged ischemia-reperfusion. During the past decade, a huge amount of work allowed to better understand the features of this protective effect as well as the molecular mechanisms. Ischemic preconditioning reduces infarct size and improves functional recovery; its effects on arrhythmias remain debated. Triggering of the protection involves cell surface receptors that activate pro-survival pathways including protein kinase C, PI3-kinase, possibly Akt and ERK1/2, whose downstream targets remain to be determined. Much attention has been recently focused on the role of mitochondrial K(+)ATP channels and the permeability transition pore that seem to play a major role in the progression toward irreversible cellular injury. Based on these experimental studies attempts have been made to transfer preconditioning from bench to bedside. Human experimental models of ischemic preconditioning have been set up, including cardiac surgery, coronary angioplasty or treadmill exercise, to perform pathophysiological studies. Yet, protecting the heart of CAD (coronary artery disease) patients requires a pharmacological approach. The IONA trial has been an example of the clinical utility of preconditioning. It helped to demonstrate that chronic administration of nicorandil, a K(+)ATP opener that mimics ischemic preconditioning in experimental preparations, improves the cardiovascular prognosis in CAD patients. Recent experimental studies appear further encouraging. It appears that "postconditioning" the heart (i.e. performing brief episodes of ischemia-reperfusion at the time of reperfusion) is as protective as preconditioning. In other words, a therapeutic intervention performed as late as at the time of reflow can still significantly limit infarct size. Further work is needed to determine whether this may be transferred to the clinical practice.     

Sevoflurane postconditioning protects isolated rat hearts against ischemia-reperfusion injury: the role of radical oxygen species,extracellular signal-related kinases 1/2 and mitochondrial permeability transition pore

The roles of reactive oxygen species (ROS), extracellular signal-regulated kinase 1/2 (ERK 1/2) and mitochondrial permeability transition pore (mPTP) in sevoflurane postconditioning induced cardioprotection against ischemia-reperfusion injury in Langendorff rat hearts were investigated. When compared with the unprotected hearts subjected to 30 min of ischemia followed by 1 h of reperfusion, exposure of 3% sevoflurane during the first 15 min of reperfusion significantly improved functional recovery, decreased infarct size, reduced lactate dehydrogenase and creatine kinase-MB release, and reduced myocardial malondialdehyde production. However, these protective effects were abolished in the presence of either ROS scavenger N-acetylcysteine or ERK 1/2 inhibitor PD98059, and accompanied by prevention of ERK 1/2 phosphorylation and elimination of inhibitory effect on mPTP opening. These findings suggested that sevoflurane postconditioning protected isolated rat hearts against ischemia-reperfusion injury via the recruitment of the ROS-ERK 1/2-mPTP signaling cascade.     

远端缺血后处理对脑缺血保护作用的研究进展

近20多年来人们对脑缺血损伤的保护研究很多,但真正能将脑缺血保护从基础研究应用到临床治疗的措施甚少。多数基础研究表明缺血预处理对大鼠脑缺血具有保护作用,然而由于脑缺血的不可预见性,研究者们将目标转向了缺血后处理。远端缺血后处理是指在非缺血器官交替实施短时间的缺血和再灌注后对缺血器官所产生的作用。由于脑组织本身对缺血的敏感,很难控制缺血后处理的程度,因此远端缺血后处理被应用到脑缺血的保护研究具有很强的临床应用价值,其机制可能与氧自由基、神经传导、蛋白质、内质网应激、Akt信号通路、线粒体途径、mitoKATP和阿片受体有关。本文主要就近几年远程缺血后处理对脑缺血保护的概念、实施方法、保护作用及分子机制做一综述。     

心肌再灌注损伤保护的机制和策略

局部缺血部位快速再灌注虽然保护了心肌,但也引起再灌注损伤。目前还没有减轻再灌注损伤的特效疗法,但近年来研究显示,G蛋白耦联受体（Gprotein-coupledreceptor,GPCR）的激动剂、胰岛素和缺血后处理可以在各种实验条件和各类动物模型中有效抵抗再灌注损伤。这些干预手段启动的心脏保护机制可能包括激活再灌注损伤补救激酶（reperfus ioninjury salvage kinase,RISK）途径、抑制糖原合酶激酶-3β（glycogen synthase kinase3β,GSK-3β）以及抑制线粒体膜通透性转换孔（mitochondrial permeabili tytransition pore,mPTP）开放等。这些研究成果有利于开发治疗急性心肌梗死的有效临床手段。     

腺苷和乙酰胆碱后适应诱导的心肌保护作用

近年来缺血后适应的提出成为抗再灌注损伤的里程碑,其良好的临床可控性和可靠的保护效应引起人们广泛关注。缺血后适应即在心肌长时间缺血后再灌注之前,进行数次短暂的再灌注,缺血的循环处理,诱导产生心肌保护效应,其循环次数和间隔时间存在种属差异。研究证实后适应不仅限制急性期梗死面积,还可以减轻长期损伤,其是否与保护血管内皮、抑制中性粒细胞介导的氧化损伤相关还存在争议。上调再灌注损伤补救激酶（reperfusion injury salvageHnase,RISK）通路是后适应保护的重要机制之一,即激活磷脂酰肌醇一3激酶（phosphatidy linositol3-kinase,P13K）-Akt途径和,或细胞外信号调节激酶（extracellular signal-regulatedkinase,ERK）途径,抑制线粒体通透性转换孔的开放,减少细胞凋亡和坏死。但是这两条途径的地位和关系还有待于进一步研究。为了更加适用于临床,研究者将机械调控转变为药物干预,观察药物能否模拟缺血后适应发挥保护作用,即药物后适应。腺苷是研究最广泛,也是最有希望成为临床正式用药的一种药物。我们实验室首先提出了乙酰胆碱可以模拟缺血后适应,通过线粒体ATP敏感钾通道发挥心肌保护效应。本文着重阐述缺血后适应保护缺血,再灌注损伤的效应和信号转导通路,尤其是腺苷和乙酰胆碱模拟药物后适应的可能机制和临床应用。     

5-脂氧合酶（5-LOX）及代谢产物在异氟醚预处理脑保护作用中的研究进展

缺血性脑血管疾病（Ischemia Cerebral Vascular Disease,ICVD）可造成不同程度的神经功能障碍,以其高发病率、高致残率、高复发率、高死亡率严重威胁着人们的身体健康。而脑组织缺血后再灌注损伤即脑缺血再灌注损伤（ischemia-reperfusion injury）是脑缺血性疾病的最主要的损伤原因之一,因此阐明脑缺血再灌注损伤发生发展的病理生理机制、探寻有效的预防保护措施成为当今研究的重点问题。本文回顾、归纳脑缺血再灌注损伤的相关分子机制及异氟醚预处理对脑缺血再灌注损伤的保护作用,分析5-脂氧合酶及其代谢产物在脑缺血再灌注损伤中的作用及其与其他分子的相互关系,旨在探讨5-脂氧合酶及其代谢产物在异氟醚预处理保护脑缺血再灌注损伤中可能起到的作用。为脑缺血再灌注损伤的防治提供更多的理论依据。     

Induction and Assessment of Ischemia-reperfusion Injury in Langendorff-perfused Rat Hearts

The biochemical events surrounding ischemia reperfusion injury in the acute setting are of great importance to furthering novel treatment options for myocardial infarction and cardiac complications of thoracic surgery. The ability of certain drugs to precondition the myocardium against ischemia reperfusion injury has led to multiple clinical trials, with little success. The isolated heart model allows acute observation of the functional effects of ischemia reperfusion injury in real time, including the effects of various pharmacological interventions administered at any time-point before or within the ischemia-reperfusion injury window. Since brief periods of ischemia can precondition the heart against ischemic injury, in situ aortic cannulation is performed to allow for functional assessment of non-preconditioned myocardium. A saline filled balloon is placed into the left ventricle to allow for real-time measurement of pressure generation. Ischemic injury is simulated by the cessation of perfusion buffer flow, followed by reperfusion. The duration of both ischemia and reperfusion can be modulated to examine biochemical events at any given time-point. Although the Langendorff isolated heart model does not allow for the consideration of systemic events affecting ischemia and reperfusion, it is an excellent model for the examination of acute functional and biochemical events within the window of ischemia reperfusion injury as well as the effect of pharmacological intervention on cardiac pre- and postconditioning. The goal of this protocol is to demonstrate how to perform in situ aortic cannulation and heart excision followed by ischemia/reperfusion injury in the Langendorff model.     

Hypercholesterolemic Myocardium Is Vulnerable to Ischemia-Reperfusion Injury and Refractory to Sevoflurane-Induced Protection

Recent studies have demonstrated that volatile anesthetic postconditioning confers myocardial protection against ischemia-reperfusion (IR) injury through activation of the reperfusion injury salvage kinase (RISK) pathway. As RISK has been shown to be impaired in hypercholesterolemia. Therefore, we investigate whether anesthetic-induced cardiac protection was maintained in hypercholesterolemic rats. In the present study, normocholesteolemic or hypercholesterolemic rat hearts were subjected to 30 min of ischemia and 2 h of reperfusion. Animals received 2.4% sevoflurane for 5 min or 3 cycles of 10-s ischemia/10-s reperfusion. The hemodynamic parameters, including left ventricular developed pressure, left ventricular end-diastolic pressure and heart rate, were continuously monitored. The infarct size, apoptosis, p-Akt, p-ERK1/2, p-GSK3β were determined. We found that both sevoflurane and ischemic postconditioning significantly improved heart pump function, reduced infarct size and increased the phosphorylation of Akt, ERK1/2 and their downstream target of GSK3β in the healthy rats. In the hypercholesterolemic rats, neither sevoflurane nor ischemic postconditioning improved left ventricular hemodynamics, reduced infarct size and increased the phosphorylated Akt, ERK1/2 and GSK3β. In contrast, GSK inhibitor SB216763 conferred cardioprotection against IR injury in healthy and hypercholesterolemic hearts. In conclusions, hyperchoesterolemia abrogated sevoflurane-induced cardioprotection against IR injury by alteration of upstream signaling of GSK3β and acute GSK inhibition may provide a novel therapeutic strategy to protect hypercholesterolemic hearts against IR injury.     

HIF 在心肌缺血再灌注中的作用

缺氧诱导因子(HIF)是参与缺氧转录反应调控的转录调控因子,HIF的活化在缺氧时细胞中保护起重要作用,HIF及HIF依赖的基因如诱导型一氧化氮合酶(iNOS)、血红素氧合酶(HO-1)的激活可减轻心脏的缺血-再灌注损伤,HIF调节的基因表达可能介导了缺血预处理和缺血后处理的保护作用。本文对HIF在心肌缺血再灌注损伤中的保护作用予以综述。     

Postconditioning reduces infarct size and cardiac myocyte apoptosis via the opioid receptor and JAK-STAT signaling pathway

Brief intermittent episodes of ischemia and reperfusion could reduce infarct size, a phenomenon called ??postconditioning?? at the onset of reperfusion after a prolonged period of ischemia. To investigate whether the opioid receptors and signaling factor JAK-STAT might be responsible for the cardioprotection in ischemic postconditioning, and the possible molecular machinery of cardioprotection. Hundred and twenty healthy New Zealand rabbits were divided into six groups. The myocardial infarct size, cardiac myocyte apoptosis, BCL-2 and P-Stat3 protein expression were tested in the current study. The results suggested that ischemic postconditioning might increase BCL-2 protein expression by activating the opioid receptors and JAK-STAT signaling pathway, and also to reduce ischemia-reperfusion-induced cardiomyocyte apoptosis and to play a key role in myocardial protection. However, further research still needs to be done to unravel the underlying mechanisms.     

缺血后处理对兔脊髓缺血再灌注微循环损伤的影响

探讨缺血后处理对兔脊髓缺血再灌注微循环损伤的影响.成年新西兰大白兔24只随机分为假手术组(C组),缺血再灌注损伤组(IR组),缺血后处理组(P组).IR组和P组采用Zivin改进法制备脊髓缺血再灌注模型,P组在缺血30 min后行复灌1 min/缺血1 min相同处理3次.采用激光多普勒检测缺血前,缺血时及再灌注各时点血流量值,在再灌注24 h时取兔脊髓组织作HE染色观察病理形态学,比色法检测脊髓组织一氧化氮(Nitric oxide,NO)的含量,放免法检测内皮素-1(Endothelin-1,ET-1)及免疫组化法检测血红素氧合酶(Hemeoxygenase-1,HO-1)的表达.研究发现与缺血前基础值相比,再灌注10 min时IR组与P组血流量均有增高,在再灌注30、60、120 min,IR组血流量值有不同程度的降低;与IR组相比,P组血流量值在再灌注各时点均有不同程度的增高.与IR组相比,P组NO含量与HO-1表达均有增加,ET-1含量明显减少,NO/ET-1显著高于IR组(P<0.05或0.01),且P组脊髓病理学损伤轻于IR组.结果表明缺血后处理可减轻兔脊髓缺血再灌注微循环损伤,改善脊髓血流量,...