This study was supported by an operating grant from the Canadian Institutes of Health Research (CIHR) to Q.F. (grant #MOP-119600).

的C57BL / 6和CD-1 IG-S小鼠繁殖对从Charles River购得。在这项研究中使用的动物，根据加拿大议会关于动物保护的准则，处理，研究方案被动物利用小组委员会在西部大学，伦敦，加拿大的批准。 1.动物护理<ol><li>分娩是完整的，幼仔已初步母乳喂养由他们的母亲了几个小时后，将它们放置在不同的笼子里带有CD-1养母。 CD-1母亲显示具有较强的本能培养一个平静的表型，并有较低的倾向蚕食受伤的幼崽15。 </li></ol> 2.手术<ol><li>通过将小狗在一个密封的腔异氟醚麻醉诱导（约500微升100％V / V异氟烷允许耗散超过1300 立方厘米室）。保持在腔室中的小鼠直到运动（约30秒）停止。 </li><li>莫删除从异氟醚室使用，并通过将鼠标放在湿冰上诱发低温麻醉。为了避免冻伤，把冰无菌手术手套里面，手套包裹内的鼠标和覆盖冰手套或包裹鼠标在无菌湿纱布，将它放在冰上。 注:小鼠更快地冷却时用冰冷的接触是在一个较大的表面面积，并且因此熔融的冰可以缩短低温诱导时间。 </li><li>缺乏运动反应到脚趾和尾巴捏麻醉确认。 注:挑起动作的停止发生在15℃和8℃之间的体温。 （冷却时间到该温度约1分钟）。完整的呼吸暂停和心脏停搏不需要 LAD结扎。 </li><li>移动至冰床装有手术显微镜手术区。确保鼠标小狗在整个手术过程中保持在冰上。 注:手术区，纱布和手术器械应灭菌。 Mainta在整个手术过程中无菌区，和穿一次性使用无菌手术手套。小鼠出生与他们的眼睛闭17不需要眼膏。 </li><li>放置在右侧卧位鼠标小狗。用聚维酮碘溶液，然后用乙醇棉签轻轻擦拭消毒的胸部。 </li><li>通过切割皮肤xyphoid和左腋下之间的左前足下面几毫米的左胸部进行皮肤切口沿腋中线。还用剪刀通过底层胸肌层进行切割。 </li><li>用钳分离肋骨，肋间肌请在第 4肋间左侧开胸。 注:新生儿肋是很脆弱的，并且可以容易破裂。要沿肋间肌开钳（而不是抓筋）避免这种情况，轻轻分开肋骨。 </li><li>可视化的左冠状动脉前降支（LAD）从左边出现AURICLE肺静脉后面和降超出心大静脉。 注意:在这个早期新生儿窗口，胸腺常常可视化并可以覆盖心脏基部的一部分。在LAD可以看出出现的胸腺的位置的旁边，这取决于胸椎切口的角度。 </li><li>通过使动脉下方11-0尼龙缝线（0.007毫米直径针）穿过中间心室左外耳（ 图1C）下面结扎LAD。缺血被确认与缝合部位（ 图1G）下方的心肌的热烫。 </li><li>关闭使用8-0尼龙缝合线（0.15毫米直径的针）胸切口​​。用两个缝合关闭肋骨。结扎，以确保针头穿过体腔时，不会刺破肺之前放置两个肋缝线。 </li><li>关闭肋骨后，从冰床鼠标。保持手术区域内的鼠标和直接将其放置在无菌手术以逢过一个温暖的加热垫在37℃开始升温。 </li><li>一旦在无菌受热面积，关闭使用8-0尼龙缝合线（0.15毫米直径的针），肌肉和皮肤层。使用一个缝合肌肉层和使用两个缝合的皮肤切口。 注:肌肉和皮肤层可以在加热垫以减少低温曝光时间关闭。鼠标温度开始上升，一旦放置在加热垫，但肌肉和皮肤缝合过程中保持足够维持麻醉足够低。 </li></ol> 3.手术恢复<ol><li>继续在一个温暖的加热垫迅速升温，直到自发运动的回报。无人看管，直到它已经恢复了足够的意识，以保持胸骨斜卧不要让动物。用乙醇棉签轻轻擦拭损伤部位取下聚维酮碘和血。 </li><li>从麻醉中足够的恢复后，从无菌手术区域中删除，从培育被褥把它涂抹妈妈的笼子里，和返回的小狗养母。这有助于防止产妇拒绝或拆。 注意:不要幼仔返回与其他动物的笼子，直到完全康复。如果整个垃圾没有被使用，并同窝留在养母，将恢复幼仔垃圾的中间。如果执行一个以上的手术，完整的老鼠返回自己的养母之前单个垃圾所需的所有手术。 </li><li>观察养母的行为向小狗每10 - 15分钟2 - 3小时，以确保接受小狗。如果母亲显示侵略朝受伤小狗，取出小狗和异氟烷过量安乐死（&gt; 5％;直到呼吸停止），随后断头。不需要围手术期镇痛药物的集中疼痛反射没有完全在这个15岁早期开发:注意。 </li></ol> 4.心肌的测量梗死面积4 -6小时后心肌梗死<ol><li>让幼崽在护理CD-1养母的恢复期限4 - 6小时。从笼中取出母亲的小狗和异氟醚过量，然后用剪子斩首安乐死吧。 </li><li>切除心脏解剖显微镜下，注意不要撕心肌。 <ol><li>切断从xyphoid过程皮肤对胸部的顶部。打开腹壁胸腔下方。抓住较低的肋骨，并通过肋骨和肌肉切断沿纵向从隔膜到腋下左侧中线，腋。 </li><li>拿在横向平面剪刀，并通过隔膜精心切割从左右侧。请务必将低于心脏水平剪刀，以免到顶点的任何损害。 </li><li>把握胸廓和切割肋右侧和肌肉沿右腋中线。用剪刀删除对心脏血管的所有连接。抓住卸下胸腔的心脏的基础。 </li></ol></li><li>部分使用手术​​碳钢刀片的心脏成三块。使沿心脏的短轴首次下调的缝合和心尖之间的中点。使在缝合（ 图3A）的电平的第二切口。 注:此留下一个顶点部分约为0.75毫米厚的重0.0018克;中间基座部分约为1毫米厚，重0.0065克;和心脏的基地。 </li><li>放置在1％2,3,5-氯化三苯基四唑（TTC）的心脏切片在室温下进行10 - 15分钟。仔细观察标本，以避免过度染色。 </li><li>为了增加对比度，用4％多聚甲醛的染色心脏切片在4℃过夜。要计算％梗死面积，心脏照片节和测量成像软件梗死面积。而梗死区域划定为白色的18存活心肌污渍红色。 </li></ol> 5.测量心功能的超声心动图后MI <ol><li>让幼崽在护理CD-1养母的恢复，为期24 - 48小时。通过将小狗在密封腔异氟醚（5％异氟醚）诱导麻醉。保持在腔室中的小鼠直到运动（约30秒）停止。 </li><li>固定小狗中在加热的基座（温度37℃），其在一锥形鼻部仰卧位以提供0.5 - 1％异氟烷（麻醉维护）。放置预温热回波凝胶左侧胸部区域。 </li><li>获取左心室（LV）的胸骨旁长轴观。确保图像被获得下面在LV缝合线的水平。获取位置后，转动超声探头（40 MHz）的90°，以获得胸骨旁短轴观，并记录M型超声心动图图像。 </li><li>测量端舒张压和结束从短轴线M模式图像收缩期左室内部直径。计算射血分数和fractio最终缩短。 </li></ol> 6.心肌的测量梗死面积24小时后MI <ol><li>让幼崽在护理CD-1养母的恢复，为期24小时。从笼中取出母亲的小狗和异氟醚过量，然后用剪子斩首安乐死吧。 </li><li>打开胸腔，如步骤4.2。切除心脏前，请认真把握只是用细镊子膜片上方的胸主动脉。持在冠状面细剪刀，平贴胸壁，并切断胸主动脉关闭后胸壁在颅方向移动剪刀。 </li><li>切断从胸壁和任何其他连接游离的主动脉，直到它到达心脏。通过抓住上腔静脉和切割到身体的所有其它血管连接切除心脏。 </li><li>冲洗心脏（附主动脉）在盐水中。仔细导管插入用30号针头胸主动脉和扎奥尔塔用8-0尼龙缝合线套管。 </li><li>以1毫升/分钟的速率灌注通过经由30号针头的主动脉内皮素-1 5ml盐水的心脏。以1毫升/分钟的速率灌注用150微升的2％伊文思蓝溶液的心脏。从套管中取出心脏，部分为三个部分和第4节与TTC留下污点。 </li><li>要计算梗死面积，心脏照片节和测量成像软件梗死面积。存活心肌渍蓝，在危险中的污渍面积红色，梗死面积划定为白色。 </li></ol>

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The authors have nothing to disclose.

这里展示了外科LAD结扎是产生的MI在新生小鼠的可靠方法。这个模型提供了一个可重复的模型来研究哺乳动物心脏再生的研究人员。冠状血管的可视化是此方法的一个关键组成部分，以确保正确的缝线放置，从而保证重复性。而成年小鼠不具有变温功能，体温和新生小鼠的代谢率是密切随环境温度相关联。此外，新生小鼠的小尺寸使其非常适用于低温诱导表面冷却。手术和鼠标体温的定时是在复?...

心肌梗死（MI）是死亡的主要原因全世界，并且仍然负责大约三分之一的心脏衰竭病例1。而经皮介入和使用血栓溶解的不断优化的出现增加了再灌注MI后，心肌细胞死亡和收缩心肌的损失仍然发生。此外，还留了大量的"无选项"病人谁不是候选人或没有看到这些措施的好处。这些患者继续经历禁用缺血导致瘢痕形成和有害的心室重构的脑梗死愈合的机制。该方法最终导致心脏衰竭，为此，预后仍然尽管与血管紧张素转换酶（ACE）抑制剂和β-阻断剂的最佳药物管理不善。遗憾的是，一年期死亡率为患者严重受损左心室功能仍然为高达26％2。心脏移植是治疗心脏衰竭的最终治疗方案。然而，对于心脏移植的有限施主池不使这对大多数患者一个可行的选择。因此，新的治疗剂的发现，以恢复受损心肌仍然是最重要解决心脏疾病的问题。因此，心脏损伤可靠的动物模型需要作为这一进程的一个重要组成部分。 传统的教条已经决定了成人的心肌细胞的有丝分裂后，终末分化细胞，不能分割或去区分，以取代受损心肌3。因此，成年哺乳动物心脏永远无法完全从伤病中恢复，失去了心肌细胞将与纤维组织所代替。因此，研究主要集中在治疗剂，以减少梗塞扩展和减少疤痕形成。然而最近，一个范式转变发生在心脏周围的愈合和许多研究工作思路已被重定向把重点放在心脏再生4的潜力。 直到最近， 在体内心脏再生的研究仅限于非脊椎动物模型，如那些在urodele两栖动物和硬骨鱼5-7。然而，在新生小鼠的能力用于心脏再生的发现已经导致的哺乳动物心脏再生的两种手术模型的开发:心尖和冠状动脉闭塞的切除以诱导心肌梗塞8,9。在2011年，一个鼠标顶点切除模型来证明完整心脏再生有可能在1日龄（P1）。然而，这种力量的初步新生儿期后迅速下降。哺乳动物的心脏在P7出生祖细胞数量下降后不久就失去了它的再生潜能，并成为心肌双核，输其增殖能力，并永久退出细胞周期10,11。了解新生和成年哺乳动物心脏之间的根本分歧可能会导致新的见解心脏再生。 而先端切除确实提供洞察收缩组织的再生长，该模型不模拟典型的人心脏损伤，因此不借给本身以及对治疗剂的开发。冠状动脉闭塞模型，然而，更直接地模拟MI病状的病理生理方面，并且因此可以提供更有用的见解可能适用于供人类使用的治疗进步的机制。 外科冠状动脉结扎已被用作在许多动物模型12-14的有用实验技术。在成人冠状动脉结扎模型中，将动物麻醉并插管以允许胸腔的开口，同时维持respirati上。该心脏继续定期击败，允许冠状血管的可视化，并允许精确缝合位置。此外，心脏仍然是粉红色的灌注继续，结扎后缺血心肌出现面色苍白，表示成功的冠状动脉结扎术。对新生小鼠中描述的协议，但是，是较不可靠的冠状动脉不可视和外科医生必须估计何处放置缝合线15。虽然冠状动脉脉管系统的一般解剖的方向是相同的，动物个体变异和在LAD的分支中存在16。因此，当"盲目去"的动脉很容易错过。然后如超声心动图的其它技术是必需的，以确认心肌梗塞的成功诱导，并确保所有的手术导致类似梗塞大小。这里描述的改善在最近发表的方法15，其中，在LAD的位置可以ESTABlished，因此LAD可连接可重复诱发心肌梗死。 这种技术不需要在新生小鼠在低温状态气管插管或机械通气，如开胸不会导致肺萎陷。然而，在前面描述的方法，严重低温必须被诱导到两个完整呼吸暂停和心律15停止的点。这种方法的主要限制是冠状动脉不再灌注和心脏甚至LAD结扎前出现面色苍白。在这里所描述的方法中，冠状动脉可视化是可能在深低温和心律停止，与手术后的新生小鼠的完全恢复之前的一个点麻木的。此方法提供100％的再现性的一大优势。

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myocardial infarction in neonatal mice, a model of cardiac regeneration

冠状动脉结扎诱发心肌梗塞已在许多动物模型被用来作为一种工具来研究心脏修复和再生机制，并定义治疗的新目标。几十年来，完整的心脏再生的模型，两栖类和鱼类存在，但哺乳动物对口不可用。近期A产后窗口发现其间的小鼠具有再生能力，导致建立心肌再生的哺乳动物模型。哺乳动物心脏再生的新生小鼠的手术模型在本文中描述。简言之，将日龄1（P1）的小鼠通过异氟烷麻醉，并放置在冰垫以诱导体温过低。胸部被打开后，与左冠状动脉前降支（LAD）被可视化，缝线周围放置在LAD以造成心肌缺血左心室。手术过程需要10-15分钟。可视化的冠状动脉被准确缝合位置和重现性是至关重要的。心肌梗死和心功能不全是由三苯基氯化四氮唑（TTC）染色和超声心动图检查确诊分别。完全再生后21天心肌梗死是由组织学验证。该协议可以用于心肌梗塞后阐明哺乳动物心脏再生的机制的工具。

在P1的心肌梗死程序可以在10内完成 - 15分钟并拥有死亡率为7.8％（5出64个幼崽）。手术后，老鼠从低温麻醉未来5内恢复 - 20分钟（恢复时间取决于体温外科医生的麻醉和速度期间达成）。当使用P7幼仔（用于与非再生心肌比较），需要冷却的一个较长时期达到麻木。 P7幼仔大得多，并有更多的困难来自心脏损伤和低温回收，导致死亡率的26.9％（14选自52幼仔）的高得多。 ...

Watch this Scientific Journal Video about Myocardial Infarction in Neonatal Mice, A Model of Cardiac Regeneration at JoVE.com

Myocardial Infarction in Neonatal Mice, A Model of Cardiac Regeneration

This protocol describes a highly reproducible model of cardiac regeneration by surgical induction of myocardial infarction in the left ventricle of postnatal day 1 mice. The method involves induction of hypothermic anesthesia and ligation of the left anterior descending coronary artery.

心肌梗死新生小鼠，心肌再生的模型

Myocardial infarction induced by coronary artery ligation has been used in many animal models as a tool to study the mechanisms of cardiac repair and ...

myocardial-infarction-in-neonatal-mice-a-model-of-cardiac-regeneration

Research

JoVE Journal

Medicine

18.3K 次观看.  Western University. This protocol describes a highly reproducible model of cardiac regeneration by surgical induction of myocardial infarction in the left ventricle of postnatal day 1 mice. The method involves induction of hypothermic anesthesia and ligation of the left anterior descending coronary artery.

视频: Myocardial Infarction in Neonatal Mice, A Model of Cardiac Regeneration

Acute Myocardial Infarction in Rats

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular diseases. Animal models that mimic human cardiac disease, such as myocardial infarction (MI) and ischemia-reperfusion (IR) that induces heart failure as well as pressure-overload (transverse aortic constriction) that induces cardiac hypertrophy and heart failure (Goldman and Tarnavski), are useful models to study cardiovascular disease. In particular, myocardial ischemia (MI) is a leading cause for cardiovascular morbidity and mortality despite controlling certain risk factors such as arteriosclerosis and treatments via surgical intervention (Thygesen). Furthermore, an acute loss of the myocardium following myocardial ischemia (MI) results in increased loading conditions that induces ventricular remodeling of the infarcted border zone and the remote non-infarcted myocardium. Myocyte apoptosis, necrosis and the resultant increased hemodynamic load activate multiple biochemical intracellular signaling that initiates LV dilatation, hypertrophy, ventricular shape distortion, and collagen scar formation. This pathological remodeling and failure to normalize the increased wall stresses results in progressive dilatation, recruitment of the border zone myocardium into the scar, and eventually deterioration in myocardial contractile function (i.e. heart failure). The progression of LV dysfunction and heart failure in rats is similar to that observed in patients who sustain a large myocardial infarction, survive and subsequently develops heart failure (Goldman). The acute myocardial infarction (AMI) model in rats has been used to mimic human cardiovascular disease; specifically used to study cardiac signaling mechanisms associated with heart failure as well as to assess the contribution of therapeutic strategies for the treatment of heart failure. The method described in this report is the rat model of acute myocardial infarction (AMI). This model is also referred to as an acute ischemic cardiomyopathy or ischemia followed by reperfusion (IR); which is induced by an acute 30-minute period of ischemia by ligation of the left anterior descending artery (LAD) followed by reperfusion of the tissue by releasing the LAD ligation (Vasilyev and McConnell). This protocol will focus on assessment of the infarct size and the area-at-risk (AAR) by Evan's blue dye and triphenyl tetrazolium chloride (TTC) following 4-hours of reperfusion; additional comments toward the evaluation of cardiac function and remodeling by modifying the duration of reperfusion, is also presented. Overall, this AMI rat animal model is useful for studying the consequence of a myocardial infarction on cardiac pathophysiological and physiological function.

The rat model of acute myocardial infarction (AMI) is useful to study the consequence of a MI on cardiac pathophysiological and physiological function.

大鼠急性心肌梗死

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular ...

科研

医学

MRI and PET in Mouse Models of Myocardial Infarction

Myocardial infarction is one of the leading causes of death in the Western world. The similarity of the mouse heart to the human heart has made it an ideal model for testing novel therapeutic strategies.
In vivo magnetic resonance imaging (MRI) gives excellent views of the heart noninvasively with clear anatomical detail, which can be used for accurate functional assessment. Contrast agents can provide basic measures of tissue viability but these are nonspecific. Positron emission tomography (PET) is a complementary technique that is highly specific for molecular imaging, but lacks the anatomical detail of MRI. Used together, these techniques offer a sensitive, specific and quantitative tool for the assessment of the heart in disease and recovery following treatment.
In this paper we explain how these methods are carried out in mouse models of acute myocardial infarction. The procedures described here were designed for the assessment of putative protective drug treatments. We used MRI to measure systolic function and infarct size with late gadolinium enhancement, and PET with fluorodeoxyglucose (FDG) to assess metabolic function in the infarcted region. The paper focuses on practical aspects such as slice planning, accurate gating, drug delivery, segmentation of images, and multimodal coregistration. The methods presented here achieve good repeatability and accuracy maintaining a high throughput.

We describe how to perform MRI and PET imaging of the mouse heart. The protocol is tailored to assess treatment efficacy in models of myocardial infarction and heart failure.

MRI和PET心肌梗死小鼠模型

Myocardial infarction is one of the leading causes of death in the Western world. The similarity of the mouse heart to the human heart has made it an ...

Myocardial Infarction and Functional Outcome Assessment in Pigs

Introduction of newly discovered cardiovascular therapeutics into first-in-man trials depends on a strictly regulated ethical and legal roadmap. One important prerequisite is a good understanding of all safety and efficacy aspects obtained in a large animal model that validly reflect the human scenario of myocardial infarction (MI). Pigs are widely used in this regard since their cardiac size, hemodynamics, and coronary anatomy are close to that of humans. Here, we present an effective protocol for using the porcine MI model using a closed-chest coronary balloon occlusion of the left anterior descending artery (LAD), followed by reperfusion. This approach is based on 90 min of myocardial ischemia, inducing large left ventricle infarction of the anterior, septal and inferoseptal walls. Furthermore, we present protocols for various measures of outcome that provide a wide range of information on the heart, such as cardiac systolic and diastolic function, hemodynamics, coronary flow velocity, microvascular resistance, and infarct size. This protocol can be easily tailored to meet study specific requirements for the validation of novel cardioregenerative biologics at different stages (i.e. directly after the acute ischemic insult, in the subacute setting or even in the chronic MI once scar formation has been completed). This model therefore provides a useful translational tool to study MI, subsequent adverse remodeling, and the potential of novel cardioregenerative agents.

This protocol describes the porcine myocardial infarction (MI) model using a 90 min closed-chest coronary balloon occlusion of the left anterior descending artery (LAD), followed by reperfusion. Furthermore, the protocol for several outcome parameters, such as cardiac function, hemodynamics, microvascular resistance, and infarct size, are also presented.

心肌梗死和功能预后评估的猪

Introduction of newly discovered cardiovascular therapeutics into first-in-man trials depends on a strictly regulated ethical and legal roadmap. One ...

Minimal Invasive Surgical Procedure of Inducing Myocardial Infarction in Mice

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last decades. For clarification of the underlying mechanisms and the development of new therapeutic strategies, the availability of valid animal models are mandatory. Since we need new insights into pathomechanisms of cardiovascular diseases under in vivo conditions to combat myocardial infarction, the validity of the animal model is a crucial aspect. However, protection of animals are highly relevant in this context. Therefore, we establish a minimally invasive and simple model of myocardial infarction in mice, which assures a high reproducibility and survival rate of animals. Thus, this models fulfils the requirements of the 3R principle (Replacement, Refinement and Reduction) for animal experiments and assure the scientific information needed for further developing of therapeutical strategies for cardiovascular diseases.

A highly reproducible model for myocardial infarction in mice with minimal invasive manipulations is described. The model can be easily performed, resulting in a high reproducibility and survival rate. Thus, the described model will reduce the number of required animals as requested by the 3R principle (Replacement, Refinement and Reduction).

在诱导小鼠心肌梗死的微创手术过程

Myocardial infarction still remains the main cause of death in western countries, despite considerable progress in the stent development area in the last ...

Permanent Ligation of the Left Anterior Descending Coronary Artery in Mice: A Model of Post-myocardial Infarction Remodelling and Heart Failure

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It is characterized by fluid retention, shortness of breath, and fatigue, in particular on exertion. Heart failure is a growing public health problem, the leading cause of hospitalization, and a major cause of mortality. Ischemic heart disease is the main cause of heart failure.
Ventricular remodelling refers to changes in structure, size, and shape of the left ventricle. This architectural remodelling of the left ventricle is induced by injury (e.g., myocardial infarction), by pressure overload (e.g., systemic arterial hypertension or aortic stenosis), or by volume overload. Since ventricular remodelling affects wall stress, it has a profound impact on cardiac function and on the development of heart failure. A model of permanent ligation of the left anterior descending coronary artery in mice is used to investigate ventricular remodelling and cardiac function post-myocardial infarction. This model is fundamentally different in terms of objectives and pathophysiological relevance compared to the model of transient ligation of the left anterior descending coronary artery. In this latter model of ischemia/reperfusion injury, the initial extent of the infarct may be modulated by factors that affect myocardial salvage following reperfusion. In contrast, the infarct area at 24 hr after permanent ligation of the left anterior descending coronary artery is fixed. Cardiac function in this model will be affected by 1) the process of infarct expansion, infarct healing, and scar formation; and 2) the concomitant development of left ventricular dilatation, cardiac hypertrophy, and ventricular remodelling.
Besides the model of permanent ligation of the left anterior descending coronary artery, the technique of invasive hemodynamic measurements in mice is presented in detail.

Heart failure is the leading cause of hospitalization and a major cause of mortality. A model of permanent ligation of the left anterior descending coronary artery in mice is applied to investigate ventricular remodelling and cardiac dysfunction post-myocardial infarction. The technique of invasive hemodynamic measurements in mice is presented.

左冠状动脉前降支的小鼠结扎:对心肌梗死后重塑和心衰模型

Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It ...

Primary Outcome Assessment in a Pig Model of Acute Myocardial Infarction

Mortality after acute myocardial infarction remains substantial and is associated with significant morbidity, like heart failure. Novel therapeutics are therefore required to confine cardiac damage, promote survival and reduce the disease burden of heart failure. Large animal experiments are an essential part in the translational process from experimental to clinical therapies. To optimize clinical translation, robust and representative outcome measures are mandatory. The present manuscript aims to address this need by describing the assessment of three clinically relevant outcome modalities in a pig acute myocardial infarction (AMI) model: infarct size in relation to area at risk (IS/AAR) staining, 3-dimensional transesophageal echocardiography (TEE) and admittance-based pressure-volume (PV) loops. Infarct size is the main determinant driving the transition from AMI to heart failure and can be quantified by IS/AAR staining. Echocardiography is a reliable and robust tool in the assessment of global and regional cardiac function in clinical cardiology. Here, a method for three-dimensional transesophageal echocardiography (3D-TEE) in pigs is provided. Extensive insight into cardiac performance can be obtained by admittance-based pressure-volume (PV) loops, including intrinsic parameters of myocardial function that are pre- and afterload independent. Combined with a clinically feasible experimental study protocol, these outcome measures provide researchers with essential information to determine whether novel therapeutic strategies could yield promising targets for future testing in clinical studies.

Reliable and accurate outcome assessment is the key for translation of preclinical therapies into clinical treatment. The current paper describes how to assess three clinically relevant primary outcome parameters of cardiac performance and damage in a pig acute myocardial infarction model.

急性心肌梗死的猪模型主要成果评估

Mortality after acute myocardial infarction remains substantial and is associated with significant morbidity, like heart failure. Novel therapeutics are ...

Real-time Pressure-volume Analysis of Acute Myocardial Infarction in Mice

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any potential therapeutic approach directed against acute left ventricular (LV) dysfunction. Current imaging modalities (e.g., echocardiography and magnetic resonance imaging) have several limitations since data on LV pressure cannot directly be measured. LV catheterization in mice undergoing coronary artery occlusion could serve as a novel method for a real-time evaluation of LV function.
At the beginning of the procedure, mice were anesthetized followed by endotracheal intubation. For LV catheterization, the right carotid artery was exposed via middle-neck incision. The catheter was introduced and placed into the LV cavity. Left thoracotomy was conducted and the left main coronary artery (LCA) was ligated. To induce reperfusion, the suture was released after 45 min. Pressure-volume data was recorded at all times.
Ligation of the LCA caused a decrease in LV systolic function as evidenced by a 30% reduction in stroke volume, LV ejection fraction (EF), and cardiac output. Maximum dP/dt as a parameter for LV contractility was also significantly reduced and diastolic function was severely impaired (minimum dP/dt -40%). Reperfusion over a period of 20 min did not lead to a complete recovery of LV function.
Real-time pressure-volume analysis served as a valid procedure for monitoring cardiac function during acute myocardial infarction in mice. Maintaining stable anesthesia and a standardized surgical approach was crucial to ensure valid results. As the early phase of acute myocardial infarction is critical for morbidity and mortality, the delineated method could be beneficial for preclinical evaluation of new strategies for cardioprotection.

Acute myocardial infarction in mice induces acute but incompletely characterized changes in left ventricular (LV) function. LV catheterization in mice undergoing coronary artery occlusion serves as a novel method for a real-time evaluation of LV function.

小鼠急性心肌梗死的实时压力容积分析

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any ...

A Cryoinjury Model to Study Myocardial Infarction in the Mouse

The use of animal models is essential for developing new therapeutic strategies for acute coronary syndrome and its complications. In this article, we demonstrate a murine cryoinjury infarct model that generates precise infarct sizes with high reproducibility and replicability. In brief, after intubation and sternotomy of the animal, the heart is lifted from the thorax. The probe of a handheld liquid nitrogen delivery system is applied onto the myocardial wall to induce cryoinjury. Impaired ventricular function and electrical conduction can be monitored with echocardiography or optical mapping. Transmural myocardial remodeling of the infarcted area is characterized by collagen deposition and loss of cardiomyocytes. Compared to other models (e.g., LAD-ligation), this model utilizes a handheld liquid nitrogen delivery system to generate more uniform infarct sizes.

This article demonstrates a model to study cardiac remodeling after myocardial cryoinjury in mice.

研究小鼠心肌梗死的低温损伤模型

The use of animal models is essential for developing new therapeutic strategies for acute coronary syndrome and its complications. In this article, we ...

Establishing a Swine Model of Post-myocardial Infarction Heart Failure for Stem Cell Treatment

Although advances have been achieved in the treatment of heart failure (HF) following myocardial infarction (MI), HF following MI remains one of the major causes of mortality and morbidity around the world. Cell-based therapies for cardiac repair and improvement of left ventricular function after MI have attracted considerable attention. Accordingly, the safety and efficacy of these cell transplantations should be tested in a preclinical large animal model of HF prior to clinical use. Pigs are widely used for cardiovascular disease research due to their similarity to humans in terms of heart size and coronary anatomy. Therefore, we sought to present an effective protocol for the establishment of a porcine chronic HF model using closed-chest coronary balloon occlusion of the left circumflex artery (LCX), followed by rapid ventricular pacing induced with pacemaker implantation. Eight weeks later, the stem cells were administered by intramyocardial injection in the peri-infarct area. Then the infarct size, cell survival, and left ventricular function (including echocardiography, hemodynamic parameters, and electrophysiology) were evaluated. This study helps establish a stable preclinical large animal HF model for stem cell treatment.

We sought to establish a swine model of heart failure induced by left circumflex artery blockage and rapid pacing to test the effect and safety of intramyocardial administration of stem cells for cell-based therapies.

建立干细胞治疗心肌梗塞心力衰竭的猪模型

Although advances have been achieved in the treatment of heart failure (HF) following myocardial infarction (MI), HF following MI remains one of the major ...

Intramyocardial Transplantation of MSC-Loading Injectable Hydrogels after Myocardial Infarction in a Murine Model

One of the major issues facing current cardiac stem cell therapies for preventing postinfarct heart failure is the low retention and survival rates of transplanted cells within the injured myocardium, limiting their therapeutic efficacy. Recently, the use of scaffolding biomaterials has gained attention for improving and maximizing stem cell therapy. The objective of this protocol is to introduce a simple and straightforward technique to transplant bone marrow-derived mesenchymal stem cells (MSCs) using injectable hydroxyphenyl propionic acid (GH) hydrogels; the hydrogels are favorable as a cell delivery platform for cardiac tissue engineering applications due to their ability to be cross-linked in situ and high biocompatibility. We present a simple method to fabricate MSC-loading GH hydrogels (MSC/hydrogels) and evaluate their survival and proliferation in three-dimensional (3D) in vitro culture. In addition, we demonstrate a technique for intramyocardial transplantation of MSC/hydrogels in mice, describing a surgical procedure to induce myocardial infarction (MI) via left anterior descending (LAD) coronary artery ligation and subsequent MSC/hydrogels transplantation.

Stem cell-based therapy has emerged as an efficient strategy to repair injured cardiac tissues after myocardial infarction. We provide an optimal in vivo application for stem cell transplantation using gelatin hydrogels that are able to be enzymatically cross-linked.

Murine 模型心肌梗塞后 MSC 加载注射水凝胶的心内移植

One of the major issues facing current cardiac stem cell therapies for preventing postinfarct heart failure is the low retention and survival rates of ...