支持这项研究是由美国国家心脏，肺和血液研究所资助R01-HL-77921和-86400（古奇奥尼JM）。

1。 Algisyl LVR植入手术（视频） <ol><li> Algisyl LVR（LONESTAR心，加利福尼亚Laguna Hills）是一个由两部分组成的钙 - 海藻酸凝胶。的Na + -海藻酸成分是4.6％甘露糖醇的Ca 2 + -海藻酸成分包括不溶于水的颗粒悬浮在无菌的4.6％的甘露糖醇溶液（0点27）的无菌水溶液。 </li><li>种植体植入的程序，可以使用标准的胸骨切开术或小前开胸有限跳动的心脏上进行。体外循环的程序是没有必要的。 </li><li>使用前右，心肌内注射（00:33）到一个注射器通过结合这两种成分混合的Na + -海藻酸成分和钙 -海藻酸成分。 </li><li> 2分钟后，两种不同类型的藻酸盐将交叉链接和形成凝胶，准备植入物放置在心肌中的方式从一个注射挠度。 </li><li>确定中旬心室游离壁的LV中间左室心尖部和基地（00:44） </li><li>从安特罗隔槽在心室中期水平，在一个约45度角插入针头，注射0.3cc的Algisyl LVR慢慢每秒（0.1毫升），在一个不间断的运动（01:15）。 </li><li>重复注射液（步骤6）在一个单一的线（圆周）沿中旬心室水平在10至19个站点，开始从的安特罗室间隔槽和止在枕颈后的隔槽。由心室，间距相隔约1厘米的植入物的大小取决于植入物的数量。 </li></ol> 2。使用数学建模量化左室压力<ol><li>使用数学模型来量化左心室壁应力之前，必须已经获得了磁共振影像（MRI）包含LV的病人的短轴与长轴切面。阿奎sition这些图像可以使用标准MRI协议（ 如张等[20]）。 </li><li>数字化过程中从MR图像包含短轴（SA）的视图的LV的LV心内膜表面，心外膜表面。这是可以做到，使用轮廓分割对象（CSO）发现在自由软件MevisLab的库。 <ol class="lalpha"><li>在我们的实验室，我们已经创建了一个程序根据发现MevisLab CSO库模块，使一个简单的“轮廓”心内膜和心外膜的边界发现在SA鉴于MR图像包含LV。真实的三维（3D）空间中的心外膜和心内膜点，然后自动生成从这些的轮廓。 </li></ol></li><li>从第2步到一个商业软件导入的三维点，Rapidform软件（INUS科技公司，Sunnyvale，CA），创建的LV心外膜和心内膜表面初始图形交换规范（IGES）格式。 Rapidform软件创建这些IGES表面所使用的步骤是： <ol class="lalpha"><li>插入/导入。 </li><li>创建多边形网格。 </li><li>输出IGES表面。 </li></ol></li><li>导入IGES表面进入商业软件TrueGrid创建一个有限元网格的LV。 <ol class="lalpha"><li>填补空间之间的心内膜和心外膜表面的八个节点的的三线性砖元件。在一般情况下，网丝，含约3000的3个元素的元素，通过壁厚足以进行建模的LV 21。 </li><li>一旦完成后，导出网格的有限元求解器LS-DYNA（LSTC，利弗莫尔，CA）作为输入甲板。更多细节在此过程中，可以发现在古奇奥尼等 23。 </li></ol></li><li>分配肌纤维方向，使用我们的内部软件的“偷心”，修改输入甲板TrueGrid出口。作为一个向量的每个元素中更紧密分配肌纤维方向器到本地心外膜的切平面平行的。这个向量是相对于本地的圆周方向上测得的角度取向。在人类的LV，这个角度被设置为线性变化的整个壁厚从心外膜，心内膜23处的60°-60°。 </li><li>写边界条件和分配心肌材料模型中的元素从第5步输入甲板。 <ol class="lalpha"><li> LV基地使用关键字“SPC”LS-DYNA施加节点位移。的的心外膜基底环中的节点是固定的，上面的LV基地节点的其余部分被限制为仅在基底面移动。 </li><li>分配的构成的法律或描述应力应变关系（见“简介”）的所有元素，使用关键字“MAT”材料标识128 LS-DYNA。 </li><li>心内膜定义元素的表面施加压力边界条件，使用关键字“LOAD_分部“。 </li><li>定义使用关键字“DEFINE_CURVE”的压力 - 时间的负荷曲线。 <ol class="lroman"><li>为了模拟舒张结束，规定时间20mmHg以下规定的舒张末压（EDP）的压力迅速增加。的压力保持恒定在电子数据处理（EDP），并有足够的时间，然后允许为LV达到稳态。 </li><li>为了模拟收缩期结束，规定的压力迅速增加从舒张末期状态，随着时间的推移，直到规定的端部达到125mmHg的收缩压（ESP）。的压力保持恒定在ESP和足够的时间，然后允许为LV达到稳态。 </li></ol></li></ol></li><li>导入完成输入甲板进入商用有限元求解器LS-DYNA计算室壁应力和低压腔体积年底舒张和收缩结束。 </li><li>调整材料的参数反映了被动的刚度和心肌收缩性未直到计算左心室腔容积匹配的舒张和收缩结束结束时MRI测定的体积。 </li></ol>

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周子扬先生是朗星心，公司雇员

Algisyl LVR注射疗法注射进入左室游离壁材料以降低室壁应力为扩张型心肌病患设计的一种新的治疗。这种治疗方法已在临床前和临床研究15渐露头角。自2012年2月以来一直在进行一项随机对照研究，以评估这种治疗严重的心脏衰竭患者（增加HF）LV隆胸的方法。 多个迭代的产品正在开发针对不同细分医师和临床需要。心胸外科医生在手术的产品版本，海藻酸钠交付在一个标准的注射器和自定义针系统专为外科医生进行注射，通过一个小切口在胸部手术（最小开胸）。一颗跳动的心脏上进行植入手术。藻酸盐的物理性能，液压后，注射到心肌肥犊类似心肌舒张，并成为一个永久的植入物。预期总手术过程的持续时间不超过60分钟，在大多数情况下，病人的曝光限制在最小的麻醉时间。第二个产品版本，可提供的程序，可以进行介入心脏病学专家和其他专家，在一些孤立的情况下，在一种非侵入性或混合性心脏病学实验室与心脏衰竭的病人。它也将允许研究急性效果。 使用数学建模量化左心室压力用数学建模的方法，用有限元方法是目前唯一的方式来精确量化体内局部室壁应力心室。结合数学建模，医疗成像如MRI，使人们能够在特定病人的VEN计算体内局部室壁应力tricles，以帮助了解这些心室的功能状态和量化注射治疗的患者的机械效应。 尽管我们已经处理的LV，在这里作为一种均匀的材料，这种方法可以是（已）的适用范围，在非均质心室，特别是量化的被检体内的室壁应力时，心肌梗死是本。在这种情况下，边界梗死和及其相邻borderzone有从MRI使用钆作为对比剂的被识别。 TrueGrid导入这些边界创建纯粹居住的元素，每个不同的区域内，即，梗死，的borderzone和偏远地区。材料参数反映病理变化在每个区域可以被分配通过LS-DYNA中各个元素。心肌梗死的病人，使用体内心肌劳损从标签MRI测量这些参数已被发现21。谁需要手术血运重建的患者往往会出现房颤，在手术后的时期，这是与质量很差标签MRI数据。这类患者也需要从手术休养几天。因此，三维超声心动图和斑点追踪可能会是一个更合适的成像方式和心肌应变测量技术比标签磁共振成像研究外科手术的急性效应。 最后，我们使用的商业软件Rapidform软件，Truegrid和LS-DYNA在这个过程中产生心室患者特定的数学模型，因为我们发现他们是在完成各自的任务效率一般。然而，其他的软件是可用的，如腕尺（用于生成有限元网格）和Abaqus（有限元求解器），也可能是适合建立数学模型的心室。

室壁应力减少被认为是在治疗心脏衰竭1的基石。在其最简单的形式给出的拉普拉斯定律，室壁应力心室和左心室压力的直径成正比，心室的壁厚是成反比的。人们普遍认为，室壁应力增加负责的不良重塑的过程中，逐步成为心室扩张，最终导致心脏衰竭2。临床和动物研究表明，增加的壁应力诱导的蛋白质，收缩元件的合成和基因表达，支持重塑过程3,4,5。壁压力增加也被证明是一个独立的预测后续左室重构6,7。 交流，已经制定了许多新的手术治疗方法和设备entral目的是降低室壁应力力图防止和扭转8,9,10患者心脏衰竭的进展。虽然这些治疗方法共享相同的目标，他们不同的方式实现它。例如，手术减少心室程序10旨在通过手术降低左心室扩张的大小，以减少室壁应力，但其结果是一个争论的主题11,12。 近日，注射液的生物相容性材料，Algisyl LVR，进入左心室扩张型心肌病的治疗在医学界已经获得了相当的关注。这种治疗方法已被证明是有效的预防或即使扭转心脏衰竭的进展在动物研究中13,14和，最近一段时间，在人类临床试验15。相反到其他设备，治疗目的是为了减少室壁应力注入材料到左心室壁加厚。 详细了解室壁应力，特别是在人类，但是，仍然是难以捉摸的。这种缺乏了解主要是因为力或应力不能直接测量，在完整的心室16。虽然封闭形式的解析，如拉普拉斯定律方程可以估算左心室壁的压力，他们开发基于严格的假设，其中包括轴对称的LV，材料的各向同性和同质内的LV。由于这些因素，室壁应力预测在实际LV，使用拉普拉斯的法律是不准确的17。要消除这些限制，以获得更准确的预测数学建模室壁应力，采用有限元（FE）方法与特定病人的心室几何应使用简化拉普拉斯的第17条代替。 有限元法是一种NUmerical技术，经常被用来解决一系列偏微分方程（PDE）描述的边界值问题。这种方法是特别有用的，当一个封闭的形式的解决方案是难以或不能获得解析。在LV的数学模型用于量化室壁应力的背景下，偏微分方程组力学平衡方程（线性动量平衡）描述的LV LV的内膜表面运动时，施加压力或负荷。当FE方法被使用时，左心室壁被分成相互连接的子域或元素（通常有8个角节点六面体），根据一个规定的应力 - 应变关系的心肌变形。 在被动充盈舒张和收缩的主动收缩期间的LV描述大变形的应力 - 应变关系，此前已在大型动物研究验证。 LV是仿照约3倍，更严厉的肌纤维方向上比在方向垂直于肌纤维方向在舒张期18。在收缩期的主动收缩是仿照通过增加沿肌纤维方向上的刚度的LV。这种刚度增加是时间的函数，并依赖于实验确定的变量，如细 ​​胞内钙浓度和肌节长度19。 使用此规定的应力 - 应变关系的心肌，有限元方法计算负载（s）适用于LV的新的基于节点的位置。一旦新的节点位置的计算，所得到的应变和应力（变形的量度）可确定在每个元素中产生的应变和应力分布的LV内。 在这里，我们勾勒出所需的步骤，植入患者的Algisyl LVR，并创建相应的特定病人的LV治疗前后的数学模型来量化的左心室壁应力。

<table border="1">
 <tbody>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>REGENTS</td>
 </tr>
 <tr>
 <td>Na+-Alginate </td>
 <td>LoneStar Heart, Inc</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Ca2+-Alginate </td>
 <td>LoneStar Heart, Inc</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td></td>
 <td></td>
 <td></td>
 <td>EQUIPMENT</td>
 </tr>
 <tr>
 <td>MevisLab</td>
 <td>Mevis Medical Solution</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>TrueGrid</td>
 <td>XYZ Scientific Application, Inc</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Rapidform</td>
 <td>Inus Technology, Inc</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>LS-Dyna</td>
 <td>Livermore Software Technology Corporation</td>
 <td></td>
 <td></td>
 </tr>
 </tbody>
</table>

reduction in left ventricular wall stress and improvement in function in failing hearts using algisyl-lvr

注射，治疗根据临床开发，Algisyl LVR用于治疗扩张型心肌病。这种治疗方法最近被用于第一次在有症状的心脏衰竭的病人。所有患者的左心室（LV），心功能明显改善，表现为持续减少的LV体积和墙体应力。在这里，我们描述了这种新的治疗方法和所采用的方法来量化其对左心室壁应力和功能。 algisyl-LVR的Na + -海藻酸和Ca 2 + -海藻酸的生物聚合物凝胶组成。的处理流程进行了由这两种成分混合，然后把它们合并成一个注射器用于心肌内注射。此混合物注入在10至19之间的中间位置的患者的左心室游离壁的基部和先端。 磁共振成像（MRI），连同数学建模，用来量化这种治疗的效果，患者治疗前，并在不同时间点的恢复过程中。心外膜和心内膜表面首先从MR图像进行数字化重建LV几何收缩末期和舒张末期。然后从这些重建表面测量左室腔体积。 建立数学模型的LV从这些MRI重建表面区域肌纤维应力的计算。被构造成使得每个LV模式1）根据先前验证的应力 - 应变关系的心肌变形，以及2）的低压腔的容积从这些模型预测在舒张末期和收缩末期相匹配的相应的MRI测定的体积。充盈规定的舒张末压加载LV内膜的表面模拟。收缩期收缩同时加载结束模拟表面ocardial一个规定最终收缩压和加入活跃收缩肌纤维方向。区域肌纤维舒张末期和收缩末期压力计算的应力 - 应变关系的基础上，从变形的LV。

到LV游离壁变厚，并且连续注射的Algisyl-LVR的LV的大小随着时间的推移降低。在MRI的LV在患者体内的收缩期结束时，接收Algisyl-LVR（ 图1）的前个月和6个月后，左心室壁的增厚和减少的LV的大小是显而易见的。 图2示出左心室壁应力的量化中所涉及的每个步骤的结果。在图2a中，心外膜和心内膜的边缘确定的LV从短轴观中的MRI和轮廓的使用MevisLab的。将得到的IGES心内膜表面（蓝色）和心外膜表面（红色）从Rapidform软件创建使用图2b中所示的轮廓点。在此之后，心内膜和心外膜表面之间的空间填充有8节点的三线性砖元件使用TrueGrid（ 图2c的 </strONG&gt;）。每个元素中定义的肌纤维方向的载体，然后计算更紧密。这些向量显示为黑色箭头在图2d和左心室壁的切片（蓝色）显示左心室壁之间的肌纤维方向的变化如前面所述。在图2e中，在LV上示出所施加的边界条件，即，压力和位移。所施加的压力所示，箭头指向心内膜壁。在所有方向上移动，而基节点的其余部分（显示为多维数据集）中的基底面（ 图2e）被限制为仅移动限制上面的的心外膜基底环（显示为球形）的节点。最后， 图2f显示从病人治疗前的舒张末计算室壁肌纤维方向的压力。从图中很明显的应力升高，发现上面的心内膜和区域左心室壁薄。 <img src="/files/ftp_upload/50096/50096fig1.jpg" alt="图1" fo:content-width="4.5in" fo:src="/files/ftp_upload/50096/50096fig1highres.jpg"/> 图1。影响Algisyl对病人的LV（箭头）6个月后，如磁共振图像上看到的图像显示，LV已经今非昔比，壁厚增加了6个月后。 <img src="/files/ftp_upload/50096/50096fig2.jpg" alt="图2" fo:content-width="4.71in" fo:src="/files/ftp_upload/50096/50096fig2highres.jpg" /> 图2。在量化左室壁应力。涉及的步骤（一）数字化的MR图像。（二）创建IGES表面。（c）建立有限元网格（四）分配肌纤维方向。（E）施加边界条件（f）计算室壁应力（舒张末）。请参阅文本解释。

Watch this Scientific Journal Video about Reduction in Left Ventricular Wall Stress and Improvement in Function in Failing Hearts using Algisyl-LVR at JoVE.com

Reduction in Left Ventricular Wall Stress and Improvement in Function in Failing Hearts using Algisyl-LVR

本文介绍了一种新型水凝胶植入失败的心和量化其影响左心室壁应力和功能的过程。这些程序已经成功应用在狗和人类。

左室壁应力和改进功能衰竭心脏使用Algisyl LVR减少

Injection of  Algisyl-LVR, a treatment under clinical development, is intended to treat  patients with dilated cardiomyopathy. This treatment was recently ...

reduction-left-ventricular-wall-stress-improvement-function-failing

Research

JoVE Journal

Medicine

24.1K 次观看.  UCSF/VA Medical Center. 本文介绍了一种新型水凝胶植入失败的心和量化其影响左心室壁应力和功能的过程。这些程序已经成功应用在狗和人类。

视频: Reduction in Left Ventricular Wall Stress and Improvement in Function in Failing Hearts using Algisyl-LVR

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of cardiovascular disease. Although molecular biology is necessary in identifying key changes in the signaling pathway, it is not a surrogate for functional significance. While physiology can provide answers to the question of function, combining physiology with biochemical assessment of metabolites in the intact, beating heart allows for a complete picture of cardiac function and energetics. For years, our laboratory has utilized isolated heart perfusions combined with nuclear magnetic resonance (NMR) spectroscopy to accomplish this task. Left ventricular function is assessed by Langendorff-mode isolated heart perfusions while cardiac energetics is measured by performing 31P magnetic resonance spectroscopy of the perfused hearts. With these techniques, indices of cardiac function in combination with levels of phosphocreatine and ATP can be measured simultaneously in beating hearts. Furthermore, these parameters can be monitored while physiologic or pathologic stressors are instituted. For example, ischemia/reperfusion or high workload challenge protocols can be adopted. The use of aortic banding or other models of cardiac pathology are apt as well. Regardless of the variants within the protocol, the functional and energetic significance of molecular modifications of transgenic mouse models can be adequately described, leading to new insights into the associated enzymatic and metabolic pathways. Therefore, 31P NMR spectroscopy in the isolated perfused heart is a valuable research technique in animal models of cardiovascular disease.

Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy

Langendorff-mode isolated heart perfusion, in conjunction with 31P NMR spectroscopy, combines the fields of biochemistry and physiology into one experiment. The protocol allows for the dynamic measurement of high energy phosphate content and turnover in the heart while concurrently monitoring physiologic function. When performed correctly, this is a valuable technique in the assessment of cardiac energetics.

在分离的小鼠使用红桃心功能和能量学的评估 31 P核磁共振

Bioengineered mouse models have become powerful research tools in determining causal relationships between molecular alterations and models of ...

科研

医学

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

颈动脉输液的紫杉烷类化合物在小鼠体内的药代动力学和药效学分析

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

Chronic Thromboembolic Pulmonary Hypertension and Assessment of Right Ventricular Function in the Piglet

An original piglet model of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) associated with chronic Right Ventricular (RV) dysfunction is described. Pulmonary Hypertension (PH) was induced in 3-week-old piglets by a progressive obstruction of the pulmonary vascular bed. A ligation of the left Pulmonary Artery (PA) was performed first through a mini-thoracotomy. Second, weekly embolizations of the right lower pulmonary lobe were done under fluoroscopic guidance with n-butyl-2-cyanoacrylate during 5 weeks. Mean Pulmonary Arterial Pressure (mPAP) measured by ritght heart catheterism, increased progressively, as well as Right Atrial pressure and Pulmonary Vascular Resistances (PVR) after 5 weeks compared to sham animals. Right Ventricular (RV) structural and functional remodeling were assessed by transthoracic echocardiography (RV diameters, RV wall thickness, RV systolic function). RV elastance and RV-pulmonary coupling were assessed by Pressure-Volume Loops (PVL) analysis with conductance method. Histologic study of the lung and the right ventricle were also performed. Molecular analyses on RV fresh tissues could be performed through repeated transcutaneous endomyocardial biopsies. Pulmonary microvascular disease in obstructed and unobstructed territories was studied from lung biopsies using molecular analyses and pathology. Furthermore, the reliability and the reproducibility was associated with a range of PH severity in animals. Most aspects of the human CTEPH disease were reproduced in this model, which allows new perspectives for the understanding of the underlying mechanisms (mitochondria, inflammation) and new therapeutic approaches (targeted, cellular or gene therapies) of the overloaded right ventricle but also pulmonary microvascular disease.

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) and Right Ventricular (RV) dysfunction were induced in piglets by progressive obstruction of the pulmonary arteries. Consequences were remarkably similar to those observed in CTEPH patients. This animal model would be a very useful tool for pathophysiology and therapeutic experiments on CTEPH and RV failure.

慢性血栓栓塞性肺动脉高压和右心室功能的仔猪评估

An original piglet model of Chronic Thromboembolic Pulmonary Hypertension (CTEPH) associated with chronic Right Ventricular (RV) dysfunction is described. ...

A Method for Quantifying Upper Limb Performance in Daily Life Using Accelerometers

A key reason for referral to rehabilitation services after stroke and other neurological conditions is to improve one's ability to function in daily life. It has become important to measure a person's activities in daily life, and not just measure their capacity for activity in the structured environment of a clinic or laboratory. A wearable sensor that is now enabling measurement of daily movement is the accelerometer. Accelerometers are commercially-available devices resembling large wrist watches that can be worn throughout the day. Data from accelerometers can quantify how the limbs are engaged to perform activities in peoples' homes and communities. This report describes a methodology to collect accelerometry data and turn it into clinically-relevant information. First, data are collected by having the participant wear two accelerometers (one on each wrist) for 24 h or longer. The accelerometry data are then downloaded and processed to produce four different variables that describe key aspects of upper limb activity in daily life: hours of use, use ratio, magnitude ratio, and the bilateral magnitude. Density plots can be constructed that visually represent the data from the 24 h wearing period. The variables and their resultant density plots are highly consistent in neurologically-intact, community-dwelling adults. This striking consistency makes them a useful tool for determining if upper limb daily performance is different from normal. This methodology is appropriate for research studies investigating upper limb dysfunction and interventions designed to improve upper limb performance in daily life in people with stroke and other patient populations. Because of its relative simplicity, it may not be long before it is also incorporated in clinical neurorehabilitation practice.

This protocol describes a method to quantify upper limb performance in daily life using wrist-worn accelerometers.

一种使用加速度计量化上肢表现在日常生活的方法

A key reason for referral to rehabilitation services after stroke and other neurological conditions is to improve one's ability to function in daily life. ...

Technique of Minimally Invasive Transverse Aortic Constriction in Mice for Induction of Left Ventricular Hypertrophy

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure overload-induced left ventricular hypertrophy (LVH) and its progression to heart failure. In the majority of the reported investigations, this procedure is performed with intubation and ventilation of the animal which renders it demanding and time-consuming and adds to the surgical burden to the animal. The aim of this protocol is to describe a simplified technique of minimally invasive TAC without intubation and ventilation of mice. Critical steps of the technique are emphasized in order to achieve low mortality and high efficiency in inducing LVH.
Male C57BL/6 mice (10-week-old, 25-30 g, n=60) were anesthetized with a single intraperitoneal injection of a mixture of ketamine and xylazine. In a spontaneously breathing animal following a 3-4 mm upper partial sternotomy, a segment of 6/0 silk suture threaded through the eye of a ligation aid was passed under the aortic arch and tied over a blunted 27-gauge needle. Sham-operated animals underwent the same surgical preparation but without aortic constriction. The efficacy of the procedure in inducing LVH is attested by a significant increase in the heart/body weight ratio. This ratio is obtained at days 3, 7, 14 and 28 after surgery (n = 6 - 10 in each group and each time point). Using our technique, LVH is observed in TAC compared to sham animals from day 7 through day 28. Operative and late (over 28 days) mortalities are both very low at 1.7%.
In conclusion, our cost-effective technique of minimally invasive TAC in mice carries very low operative and post-operative mortalities and is highly efficient in inducing LVH. It simplifies the operative procedure and reduces the strain put on the animal. It can be easily performed by following the critical steps described in this protocol.

The aim of this protocol is to describe step-by-step the technique of minimally invasive transverse aortic constriction (TAC) in mice. By elimination of intubation and ventilation which are mandatory for the commonly used standard procedure, minimally invasive TAC simplifies the operative procedure and reduces the strain put on the animal.

小鼠横主动脉狭窄诱导左心室肥厚的技术研究

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure ...

Studying Left Ventricular Reverse Remodeling by Aortic Debanding in Rodents

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, mice undergo RR upon removal of the aortic constriction. In this paper, we describe a step-by-step procedure to perform a minimally invasive surgical aortic debanding in mice. Echocardiography was subsequently used to assess the degree of cardiac hypertrophy and dysfunction during LV remodeling and RR and to determine the best timing for aortic debanding. At the end of the protocol, terminal hemodynamic evaluation of the cardiac function was conducted, and samples were collected for histological studies. We showed that debanding is associated with surgical survival rates of 70-80%. Moreover, two weeks after debanding, the significant reduction of ventricular afterload triggers the regression of ventricular hypertrophy (~20%) and fibrosis (~26%), recovery of diastolic dysfunction as assessed by the normalization of left ventricular filling and end-diastolic pressures (E/e&#39;&#160;and LVEDP). Aortic debanding is a useful experimental model to study LV RR in rodents. The extent of myocardial recovery is variable between subjects, therefore, mimicking the diversity of RR that occurs in the clinical context, such as aortic valve replacement. We conclude that the aortic banding/debanding model represents a valuable tool to unravel novel insights into the mechanisms of RR, namely the regression of cardiac hypertrophy and the recovery of diastolic dysfunction.

Here we describe a step-by-step protocol of surgical aorta debanding in the well-established mice model of aortic-constriction. This procedure not only allows studying the mechanisms underlying the left ventricular reverse remodeling and regression of hypertrophy but also to test novel therapeutic options that might accelerate myocardial recovery.

研究左心室反向改造由主动脉脱体在啮齿动物

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, ...

Using a Chemical Biopsy for Graft Quality Assessment

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated with an increased survival rate and greater quality of patient&#8217;s life when compared to conventional dialysis. Regrettably, transplantology suffers from a lack of reliable methods for organ quality assessment. Standard diagnostic techniques are limited to macroscopic appearance inspection or invasive tissue biopsy, which do not provide comprehensive information about the graft. The proposed protocol aims to introduce solid phase microextraction (SPME) as an ideal analytical method for comprehensive metabolomics and lipidomic analysis of all low molecular compounds present in kidneys allocated for transplantation. The small size of the SPME probe enables performance of a chemical biopsy, which enables extraction of metabolites directly from the organ without any tissue collection. The minimum invasiveness of the method permits execution of multiple analyses over time: directly after organ harvesting, during its preservation, and immediately after revascularization at the recipient&#8217;s body. It is hypothesized that the combination of this novel sampling method with a high-resolution mass spectrometer will allow for discrimination of a set of characteristic compounds that could serve as biological markers of graft quality and indicators of possible development of organ dysfunction.

The protocol presents utilization of the chemical biopsy approach followed by comprehensive metabolomic and lipidomic analysis for quality assessment of kidney grafts allocated for transplantation.

使用化学活检进行移植质量评估

Kidney transplantation is a life-saving treatment for a large number of people with end-stage renal dysfunction worldwide. The procedure is associated ...

On-Site Sampling and Extraction of Brain Tumors for Metabolomics and Lipidomics Analysis

Despite the variety of tools available for cancer diagnosis and classification, methods that enable fast and simple characterization of tumors are still in need. In recent years, mass spectrometry has become a method of choice for untargeted profiling of discriminatory compound as potential biomarkers of a disease. Biofluids are generally considered as preferable matrices given their accessibility and easier sample processing while direct tissue profiling provides more selective information about a given cancer. Preparation of tissues for the analysis via traditional methods is much more complex and time-consuming, and, therefore, not suitable for fast on-site analysis. The current work presents a protocol combining sample preparation and extraction of small molecules on-site, immediately after tumor resection. The sampling device, which is of the size of an acupuncture needle, can be inserted directly into the tissue and then transported to the nearby laboratory for instrumental analysis. The results of metabolomics and lipidomics analyses demonstrate the capability of the approach for the establishment of phenotypes of tumors related to the histological origin of the tumor, malignancy, and genetic mutations, as well as for the selection of discriminating compounds or potential biomarkers. The non-destructive nature of the technique permits subsequent performance of routinely used tests e.g., histological tests, on the same samples used for SPME analysis, thus enabling attainment of more comprehensive information to support personalized diagnostics.

The manuscript presents on-site sampling of human brain tumors with solid phase microextraction followed by their biochemical profiling towards the discovery of biomarkers.

代谢组学和利皮多米分析脑肿瘤的现场采样与提取

Despite the variety of tools available for cancer diagnosis and classification, methods that enable fast and simple characterization of tumors are still ...

Echocardiographic Characterization of Left Ventricular Structure, Function, and Coronary Flow in Neonate Mice

Echocardiography is a non-invasive procedure that enables the evaluation of structural and functional parameters in animal models of cardiovascular disease and is used to assess the impact of potential treatments in preclinical studies. Echocardiographic studies are usually conducted in young adult mice (i.e., 4-6 weeks of age). The evaluation of early neonatal cardiovascular function is not usually performed because of the small size of the mouse pups and the associated technical difficulties. One of the most important challenges is that the short length of the pups&#39; limbs prevents them from reaching the electrodes in the echocardiography platform. Body temperature is the other challenge, as pups are very susceptible to changes in temperature. Therefore, it is important to establish a practical guide for performing echocardiographic studies in small mouse pups to help researchers detect early pathological changes and study the progression of cardiovascular disease over time. The current work describes a protocol for performing echocardiography in mouse pups at the early age of 7 days old. The echocardiographic characterization of cardiac morphology, function, and coronary flow in neonatal mice is also described.

The present protocol describes the echocardiographic assessment of left ventricular morphology, function, and coronary blood flow in 7-day old neonate mice.

新生小鼠左心室结构、功能和冠状动脉血流的超声心动图表征

Echocardiography is a non-invasive procedure that enables the evaluation of structural and functional parameters in animal models of cardiovascular ...

A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement

High-Intensity Interval Training (HIIT) has emerged as an interesting time-efficient approach to increase exercise adherence and improve health. However, few studies have tested the efficiency of HIIT protocols in a &#34;real world&#34; setting, e.g., HIIT protocols designed for outdoor spaces without specialized equipment. This study presents a &#34;real world&#34; training protocol, named &#34;beep training&#34;, and compares the efficiency of a HIIT regiment versus a traditional long-duration Moderate-Intensity Continuous Training (MICT) regiment using this beep training protocol on VO2 max of overweight untrained men. Twenty-two subjects performed outdoor running with MICT (n = 11) or HIIT (n = 11). Cardiorespiratory fitness was assessed before and after training protocols using a metabolic analyzer. Both training protocols were performed 3 days a week for 8 weeks using the Beep Test results. The MICT group performed the exercise program at 60%-75% of the maximum speed of the 20 m shuttle test (Vmax) and with a progression of the distance of 3,500-5,000 m. The HIIT group performed the interval exercise with 7-10 bouts of 200 m at 85%-100% of the maximum speed of the 20 m shuttle test (Vmax), interspersed with 1 min of passive recovery. Although the HIIT group presented a significantly lower training volume than the MICT group (p &#60; 0.05) after 8 weeks of beep training, HIIT was superior to MICT in improving VO2 max (MICT: ~4.1%; HIIT: ~7.3%; p &#60; 0.05). The &#34;real world&#34; HIIT regiment based on beep training protocol is a time-efficient, low-cost, and easy-to-implement protocol for overweight untrained men.

This study presents a low-cost and easy-to-implement "real world" high-intensity interval training (HIIT) protocol for scientific research and discusses its efficiency for cardiorespiratory fitness.

一种用于改善心肺健康的真实世界高强度间歇训练方案

High-Intensity Interval Training (HIIT) has emerged as an interesting time-efficient approach to increase exercise adherence and improve health. However, ...