Name: echocardiographic measurement of right ventricular diastolic parameters in mouse
Uploaded: 2019-04-27T12:30:00
Description: Watch this Scientific Journal Video about Echocardiographic Measurement of Right Ventricular Diastolic Parameters in Mouse at JoVE.com

The study was funded by the Ludwig Boltzmann Institute for Lung Vascular Research.

The study was performed according to national regulations for animal experimentation and EU Directive 2010/63. Prepare equipment as described previously by Brittain&#160;et al.8.
1. Mouse Preparation
<ol>
	<li>Obtain 12&#160;to 13 week-old male C57Bl6/J mice and house them with a 12 h light/dark cycle, at a constant room temperature, and with ad libitum access to standard laboratory chow and water, until the start of the experiment.</li>
	<li>Anesthetize the ...

<ol>
	<li>Egemnazarov, B., Crnkovic, S., Nagy, B. M., Olschewski, H., Kwapiszewska, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Right+ventricular+fibrosis+and+dysfunction:+Actual+concepts+and+common+misconceptions.">Right ventricular fibrosis and dysfunction: Actual concepts and common misconceptions.</a> Matrix Biology: Journal of the International Society for Matrix Biology. 68-69, 507-521 (2018).</li><li>Rain, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Right+ventricular+diastolic+impairment+in+patients+with+pulmonary+arterial+hypertension.">Right ventricular diastolic impairment in patients with pulmonary arterial hypertension.</a> Circulation. 128, 1-10 (2013).</li><li>Egemnazarov, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pressure+overload+creates+right+ventricular+diastolic+dysfunction+in+a+mouse+model:+assessment+by+echocardiography.">Pressure overload creates right ventricular diastolic dysfunction in a mouse model: assessment by echocardiography.</a> Journal of the American Society of Echocardiography. 28, 828-843 (2015).</li><li>Crnkovic, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+and+molecular+factors+associated+with+TAPSE+in+hypoxic+pulmonary+hypertension.">Functional and molecular factors associated with TAPSE in hypoxic pulmonary hypertension.</a> American Journal of Physiology. Lung Cellular and Molecular Physiology. 311, 59-73 (2016).</li><li>Shi, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=miR-223-IGF-IR+signalling+in+hypoxia-+and+load-induced+right-ventricular+failure:+a+novel+therapeutic+approach.">miR-223-IGF-IR signalling in hypoxia- and load-induced right-ventricular failure: a novel therapeutic approach.</a> Cardiovascular Research. 111, 184-193 (2016).</li><li>de Raaf, M. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tyrosine+kinase+inhibitor+BIBF1000+does+not+hamper+right+ventricular+pressure+adaptation+in+rats.">Tyrosine kinase inhibitor BIBF1000 does not hamper right ventricular pressure adaptation in rats.</a> American Journal of Physiology - Heart and Circulatory Physiology. 311, 604-612 (2016).</li><li>Zhou, Y. Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comprehensive+transthoracic+cardiac+imaging+in+mice+using+ultrasound+biomicroscopy+with+anatomical+confirmation+by+magnetic+resonance+imaging.">Comprehensive transthoracic cardiac imaging in mice using ultrasound biomicroscopy with anatomical confirmation by magnetic resonance imaging.</a> Physiological Genomics. 18, 232-244 (2004).</li><li>Brittain, E., Penner, N. L., West, J., Hemnes, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Echocardiographic+assessment+of+the+right+heart+in+mice.">Echocardiographic assessment of the right heart in mice.</a> Journal of Visualized Experiments. (81), e50912 (2013).</li><li>Kitchen, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonparametric+vs+parametric+tests+of+location+in+biomedical+research.">Nonparametric vs parametric tests of location in biomedical research.</a> American Journal of Ophthalmology. 147, 571-572 (2009).</li><li>Yan, F., Robert, M., Li, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Statistical+methods+and+common+problems+in+medical+or+biomedical+science+research.">Statistical methods and common problems in medical or biomedical science research.</a> International Journal of Physiology, Pathophysiology and Pharmacology. 9, 157-163 (2017).</li><li>Guihaire, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Non-invasive+indices+of+right+ventricular+function+are+markers+of+ventricular-arterial+coupling+rather+than+ventricular+contractility:+insights+from+a+porcine+model+of+chronic+pressure+overload.">Non-invasive indices of right ventricular function are markers of ventricular-arterial coupling rather than ventricular contractility: insights from a porcine model of chronic pressure overload.</a> European Heart Journal Cardiovascular Imaging. 14, 1140-1149 (2013).</li><li>Sareen, N., Ananthasubramaniam, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain+Imaging:+From+Physiology+to+Practical+Applications+in+Daily+Practice.">Strain Imaging: From Physiology to Practical Applications in Daily Practice.</a> Cardiology in Review. 24, 56-69 (2016).</li><li>Thavendiranathan, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+myocardial+strain+imaging+by+echocardiography+for+the+early+detection+of+cardiotoxicity+in+patients+during+and+after+cancer+chemotherapy:+a+systematic+review.">Use of myocardial strain imaging by echocardiography for the early detection of cardiotoxicity in patients during and after cancer chemotherapy: a systematic review.</a> Journal of the American College of Cardiology. 63, 2751-2768 (2014).</li><li>Sengelov, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Global+Longitudinal+Strain+Is+a+Superior+Predictor+of+All-Cause+Mortality+in+Heart+Failure+With+Reduced+Ejection+Fraction.">Global Longitudinal Strain Is a Superior Predictor of All-Cause Mortality in Heart Failure With Reduced Ejection Fraction.</a> JACC: Cardiovascular Imaging. 8, 1351-1359 (2015).</li><li>Silvani, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physiological+Mechanisms+Mediating+the+Coupling+between+Heart+Period+and+Arterial+Pressure+in+Response+to+Postural+Changes+in+Humans.">Physiological Mechanisms Mediating the Coupling between Heart Period and Arterial Pressure in Response to Postural Changes in Humans.</a> Frontiers in Physiology. 8, 163 (2017).</li><li>Mohan, M., Anandh, B., Thombre, D. 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The echocardiographic RV function and dimension assessment from parasternal positions have been well described. In contrast, the apical position in mouse echocardiography has been neglected partly due to technical difficulties. Using a horizontal platform position, it is difficult to obtain a sufficient acoustic window for four-chamber view imaging. To facilitate the imaging of this position, the platform can be tilted to the left, a manipulation similar to the left-sided positioning of patients. This should result in a ...

Diastolic dysfunction is a prominent feature of right ventricular (RV) remodeling1 and is associated with pressure-overload conditions2. Echocardiography (EchoCG) can be used for the characterization of RV diastolic dysfunction3,4. Despite recent developments in small animal echocardiography, measurements of diastolic parameters are rarely reported. In contrast, measurements of the systolic function are widely used for the characterization of transgenic mice5, as well as for the evaluation of a treatment response6.
This can be partly explained by the difficulties in the measurement of diastolic parameters from the apical four-chamber view. Visualization of the heart in this position can be facilitated by tilting the fixation platform LeCa or RiCr. Even if these manipulations are used, echocardiographers do not report them in their manuscripts4,7. Therefore, it remains unclear whether these manipulations provide comparable results. Moreover, this also precludes a development of standardized nomenclature of this position for mice.
The aim of this study was to describe two positions for apical four-chamber view visualization and compare their results. To determine the differences between the two positions, we have utilized the mouse pulmonary artery banding (PAB) model, in which a tantalum clip leads to a partial occlusion of the pulmonary artery. This occlusion results in right ventricle remodeling and dysfunction. Full details of the PAB operation can be found in previously published work3. Sham-operated mice, where the clip was placed next to the pulmonary artery, were used for comparison. EchoCG investigations were performed three weeks post-operation using the imaging system with a 30 MHz scan head (see Table of Materials for both). Nomenclature for the description of the positions and orientations between the mouse and the ultrasound beam is used as described by Zhou et al.7.

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		<col />
		<col />
		<col />
		<col />
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	<tbody>
		<tr height="40">
			<td height="40" style="height:40px;width:244px;">RMV-707B scan head 30 MHz</td>
			<td style="width:189px;">Visual Sonics</td>
			<td style="width:239px;">P/N 11459</td>
			<td style="width:167px;">mouse scan head</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">VisualSonics Vevo 770&#174; High-Resolution Imaging System</td>
			<td>Visual Sonics</td>
			<td>770-230</td>
			<td>ultrasound machine</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Veet depilation creme for sensitive skin</td>
			<td>Veet</td>
			<td>07768307&#160;</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Surgical tape Durapore 3M</td>
			<td>3M Deutschland GmbH</td>
			<td>1538-1</td>
			<td>for fixation</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Askina Brauncel cellulose swabs</td>
			<td>B.Braun</td>
			<td>9051015</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Aquasonic ultrasound gel</td>
			<td>Parker Laboratories Inc.</td>
			<td>BT025-0037L</td>
			<td></td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Electrode Gel</td>
			<td>GE medical systems information technologies Inc.</td>
			<td>2034731-002</td>
			<td>apply to extremities for countinous ECG and heart rate monitoring</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">Thermasonic gel warmer</td>
			<td>Parker Laboratories Inc.</td>
			<td>82-04-20</td>
			<td>to reduce heat loss warm up the ultrasound gel before use</td>
		</tr>
	</tbody>
</table>

echocardiographic measurement of right ventricular diastolic parameters in mouse

Diastolic dysfunction is a prominent feature of right ventricular (RV) remodeling associated with conditions of pressure overload. However, the RV diastolic function is rarely quantified in experimental studies. This might be due to technical difficulties in the visualization of the RV in the apical four-chamber view in rodents. Here we describe two positions facilitating the visualization of the apical four-chamber view in mice to assess the RV diastolic function.
The apical four-chamber view is enabled by tilting the mouse fixation platform to the left and caudally (LeCa) or to the right and cranially (RiCr). Both positions provide images of comparable quality. The results of the RV diastolic function obtained from two positions are not significantly different. Both positions are comparably easy to perform. This protocol can be incorporated into published protocols and enables detailed investigations of the RV function.

The apical four-chamber view is difficult to obtain in mice. Therefore, manipulations of the platform position can help to visualize the heart by changing its position in the thorax. The tilting of the platform to the left and to the right improved the acoustic window and provided images of comparable quality in B-mode (Figure 1). After obtaining the correct positions, measurements in PW-, M-, and TDI-modes provided images of comparable quality (<strong class...

Watch this Scientific Journal Video about Echocardiographic Measurement of Right Ventricular Diastolic Parameters in Mouse at JoVE.com

Echocardiographic Measurement of Right Ventricular Diastolic Parameters in Mouse

Here we describe and compare two positions for obtaining the apical four-chamber view in mice. These positions enable the quantification of the right ventricular function, provide comparable results, and can be used interchangeably.

Diastolic dysfunction is a prominent feature of right ventricular (RV) remodeling associated with conditions of pressure overload. However, the RV ...

Usually visualization of the apical four chamber view is possible only in 65 to 70%of investigated mice. The main advantage of this technique is that the combined usage of both tilting positions enables that requisition in almost all investigated mice. After the mouse has reached the appropriate level of light sedation, fix the mouse on a heated platform and apply electrode gel to the extremities for continuous monitoring of the heart rate and temperature.Remove the chest hair with depilatory cream and apply a layer of ultrasound coupling gel to the tip of the transducer. For an apical four chamber view with the left and caudal platform tilt, angle the platform 10 to 15 degrees to the left and 10 to 15 degrees caudally. Position the transducer above the apex within the imaging plane, 45 degrees to the coronal plane with the central axis of the ultrasound beam directed cranially posteriorly and to the left.Press the B-mode button to activate the B-mode to de-imaging and locate the left ventricul, left atrium, right ventricle, right atrium, mitral valve and tricuspid valve on the acoustic window. To ensure that you are in the right position slide the transducer up and down along the coronal plane. Manipulate the imagine plane in the coronal plane and rotate clock and counter clockwise around the central axis until both ventricles are visualized at their longest dimension, and both atria are visible to obtain the four chamber view.Press cine store to save the recording. Then press scan freeze to pause the system. To measure the transtricuspid blood flow velocity press scan freeze to activate the system and press overlay several times to activate the sample volume for the post wave mode.With the four chamber imaging view use the track ball to position the sample volume at the opening of the tricuspid valves and click pulse wave mode to measure the inflow velocities. Click cine store to save the optimized recording followed by scan freeze to pause the system. For measurement of the tricuspid annular plane systolic excursion, click scan freeze to activate the system and switch to B-mode.Some manipulations of the image might be necessary to regain the correct four chamber view. Click overlay several times to activate the sample volume of the M-mode and use the trackball to align the sample volume with the lateral part of the tricuspid annulus. Use the trackball to pull the edges of the sample volume until the entire amplitude of the cardiac movement during the cardiac cycle is covered.And activate the M-mode. The tricuspid annulus movements should appear as a wave, then click cine store to save the recording and scan freeze to pause the system. For measurement of the tissue doppler parameters activate the system and the B-mode.Click overlay several times to activate the sample volume for tissue doppler imaging and use the trackball to align the sample volume with the lateral part of the tricuspid annulus, such that the right ventricle free wall creates an angle with the tricuspid valve. Pull the edges of the sample to adjust the sample volume to include the systolic and diastolic extreme positions of the annulus, and click tissue to activate the tissue doppler imaging mode. Then click cine store to save the recording and scan freeze to pause the system.Tilting the platform to the left and to the right improves the acoustic window and provides images of comparable quality in healthy and diseased mouse hearts in the B-mode. After obtaining the correct positions, measurements in the M-mode, tissue doppler imaging mode and pulsed wave mode provide images of comparable quality with similar diastolic parameter results obtained in either the right cranial or left caudal platform positions in both healthy and diseased hearts. Further, correlation analysis reveals a good agreement between the values obtained from these two facilitated positions.While attempting this procedure it's important to remember that echocardiography is a non-invasive technique for the evaluation of the cardiac function. Following this procedure, tissue samples can be collected after the physiological measurements to answer additional questions about the morphologic substrate or molecular mechanisms of cardiac dysfunction. This technique has paved the way for the researchers in the field of pulmonary hypertension to explore the mechanisms of the right ventricle adaptation to pressure overload using mouse models of pulmonary hypertension.To obtain the producible results between experiments, tightly control the physiological parameters of the animal such as heart rate and body temperature and maintain the level of anesthesia as superficial as possible to minimize influencing cardiac function.

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Research

JoVE Journal

Medicine

Echocardiographic Assessment of the Right Heart in Mice

Transgenic and toxic models of pulmonary arterial hypertension (PAH) are widely used to study the pathophysiology of PAH and to investigate potential therapies. Given the expense and time involved in creating animal models of disease, it is critical that researchers have tools to accurately assess phenotypic expression of disease. Right ventricular dysfunction is the major manifestation of pulmonary hypertension. Echocardiography is the mainstay of the noninvasive assessment of right ventricular function in rodent models and has the advantage of clear translation to humans in whom the same tool is used. Published echocardiography protocols in murine models of PAH are lacking.
In this article, we describe a protocol for assessing RV and pulmonary vascular function in a mouse model of PAH with a dominant negative BMPRII mutation; however, this protocol is applicable to any diseases affecting the pulmonary vasculature or right heart. We provide a detailed description of animal preparation, image acquisition and hemodynamic calculation of stroke volume, cardiac output and an estimate of pulmonary artery pressure.

This article provides a protocol for the echocardiographic assessment of right ventricular size and pulmonary hypertension in mice. Applications include phenotype determination and serial assessment in transgenic and toxin-induced mouse models of cardiomyopathy and pulmonary vascular disease.

Transgenic and toxic models of pulmonary arterial hypertension (PAH) are widely used to study the pathophysiology of PAH and to investigate potential ...

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, ...

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.

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

Assessment of Sarcoplasmic Reticulum Calcium Reserve and Intracellular Diastolic Calcium Removal in Isolated Ventricular Cardiomyocytes

Intracellular calcium recycling plays a critical role in regulation of systolic and diastolic function in cardiomyocytes. Cardiac sarcoplasmic reticulum (SR) serves as a Ca2+ reservoir for contraction, which reuptakes intracellular Ca2+ during relaxation. The SR Ca2+ reserve available for beats is determinate for cardiac contractibility, and the removal of intracellular Ca2+ is critical for cardiac diastolic function. Under some pathophysiological conditions, such as diabetes and heart failure, impaired calcium clearance and SR Ca2+ store in cardiomyocytes may be involved in the progress of cardiac dysfunction. Here, we describe a protocol to evaluate SRCa2+ reserve and diastolic Ca2+ removal. Briefly, a single cardiomyocyte was enzymatically isolated, and the intracellular Ca2+ fluorescence indicated by Fura-2 was recorded by a calcium imaging system. To employ caffeine for inducing total SR Ca2+ release, we preset an automatic perfusion switch program by interlinking the stimulation system and the perfusion system. Then, the mono-exponential curve fitting was used for analyzing decay time constants of calcium transients and caffeine-induced calcium pulses. Accordingly, the contribution of the SR Ca2+-ATPase (SERCA) and Na+-Ca2+ exchanger (NCX) to diastolic calcium removal was evaluated.

Intracellular calcium recycling plays a critical role in regulation of systolic and diastolic function in cardiomyocytes. Here, we describe a protocol to evaluate sarcoplasmic reticulum Ca2+ reserve and diastolic calcium removal function in cardiomyocytes by a calcium imaging system.

Intracellular calcium recycling plays a critical role in regulation of systolic and diastolic function in cardiomyocytes. Cardiac sarcoplasmic reticulum ...

Echocardiographic and Histological Examination of Cardiac Morphology in the Mouse

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed in mice is high. Phenotypic characterization of these mouse models also requires the examination of cardiac function and morphology. Echocardiography and magnetic resonance imaging (MRI) are commonly used approaches to characterize cardiac function and morphology in mice. Echocardiographic and MRI equipment specialized for use in small rodents is&#160;expensive and requires a dedicated space. This protocol describes cardiac measurements in mice using a clinical echocardiographic system with a 15 MHz human vascular probe. Measurements are performed on anesthetized adult mice. At least three image sequences are recorded and analyzed for each animal in M-mode in the parasternal short-axis view. Afterwards, cardiac histological examination is performed, and cardiomyocyte diameters are determined on hematoxylin-eosin- or wheat germ agglutinin (WGA)-stained paraffin sections. Vessel density is determined morphometrically after Pecam-1 immunostaining. The protocol has been applied successfully to pharmacological studies and different genetic animal models under baseline conditions, as well as after experimental myocardial infarction by the permanent ligation of the left anterior descending coronary artery (LAD). In our experience, echocardiographic investigation is limited to anesthetized animals and is feasible in adult mice weighing at least 25 g.

Echocardiographic examination is frequently used in mice. Expensive high-resolution ultrasound devices have been developed for this purpose. This protocol describes an affordable echocardiographic procedure combined with histological morphometric analyses to determine cardiac morphology.

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed ...

A Pulmonary Trunk Banding Model of Pressure Overload Induced Right Ventricular Hypertrophy and Failure

Right ventricular (RV) failure induced by sustained pressure overload is a major contributor to morbidity and mortality in several cardiopulmonary disorders. Reliable and reproducible animal models of RV failure are therefore warranted in order to investigate disease mechanisms and effects of potential therapeutic strategies. Banding of the pulmonary trunk is a common method to induce isolated RV hypertrophy but in general, previously described models have not succeeded in creating a stable model of RV hypertrophy and failure.
We present a rat model of pressure overload induced RV hypertrophy caused by pulmonary trunk banding (PTB) that enables different phenotypes of RV hypertrophy with and without RV failure. We use a modified ligating clip applier to compress a titanium clip around the pulmonary trunk to a pre-set inner diameter. We use different clip diameters to induce different stages of disease progression from mild RV hypertrophy to decompensated RV failure.
RV hypertrophy develops consistently in rats subjected to the PTB procedure and depending on the diameter of the applied banding clip, we can accurately reproduce different disease severities ranging from compensated hypertrophy to severe decompensated RV failure with extra-cardiac manifestations.
The presented PTB model is a valid and robust model of pressure overload induced RV hypertrophy and failure that has several advantages to other banding models including high reproducibility and the possibility of inducing severe and decompensated RV failure.

We present a surgical method to induce right ventricular hypertrophy and failure in rats.

Right ventricular (RV) failure induced by sustained pressure overload is a major contributor to morbidity and mortality in several cardiopulmonary ...

Transthoracic Echocardiographic Examination in the Rabbit Model

Large animal models such as the rabbit are valuable for translational preclinical research. Rabbits have a similar cardiac electrophysiology compared to that of humans and that of other large animal models such as dogs and pigs. However, the rabbit model has the additional advantage of lower maintenance costs compared to other large animal models. The longitudinal evaluation of cardiac function using echocardiography, when appropriately implemented, is a useful methodology for preclinical assessment of novel therapies for heart failure with reduced ejection fraction (e.g. cardiac regeneration). The correct use of this non-invasive tool requires the implementation of a standardized examination protocol following international guidelines. Here we describe, step by step, a detailed protocol supervised by veterinary cardiologists for performing echocardiography in the rabbit model, and demonstrate how to correctly obtain the different echocardiographic views and imaging planes, as well as the different imaging modes available in a clinical echocardiography system routinely used in human and veterinary patients.

Here we describe, step by step, a detailed protocol for performing echocardiography in the rabbit model. We show how to correctly obtain the different echocardiographic views and imaging planes, as well as the different imaging modes available in a clinical echocardiography system routinely used in human and veterinary patients.

Large animal models such as the rabbit are valuable for translational preclinical research. Rabbits have a similar cardiac electrophysiology compared to ...

Invasive Hemodynamic Assessment for the Right Ventricular System and Hypoxia-Induced Pulmonary Arterial Hypertension in Mice

Pulmonary arterial hypertension (PAH) is a chronic and severe cardiopulmonary disorder. Mice are a popular animal model used to mimic this disease. However, the evaluation of right ventricular pressure (RVP) and pulmonary artery pressure (PAP) remains technically challenging in mice. RVP and PAP are more difficult to measure than left ventricular pressure because of the anatomical differences between the left and right heart systems. In this paper, we describe a stable right heart hemodynamic measurement method and its validation using healthy and PAH mice. This method is based on open-chest surgery and mechanical ventilation support. It is a complicated procedure compared to closed chest procedures. While a well-trained surgeon is required for this surgery, the advantage of this procedure is that it can generate both RVP and PAP parameters at the same time, so it is a preferable procedure for the evaluation of PAH models.

Here, we present a protocol to perform an invasive hemodynamic assessment of the right ventricle and pulmonary artery in mice using an open-chest surgery approach.

Pulmonary arterial hypertension (PAH) is a chronic and severe cardiopulmonary disorder. Mice are a popular animal model used to mimic this disease. ...

Generation and Characterization of Right Ventricular Myocardial Infarction Induced by Permanent Ligation of the Right Coronary Artery in Mice

Right ventricular infarction (RVI) is a common presentation in clinical practice. Severe RVI can lead to fatal hemodynamic dysfunction and arrhythmia. In contrast to the extensively used mouse myocardial infarction (MI) model generated by left coronary artery ligation, the RVI mouse model is rarely employed due to the difficulty associated with model generation. Research on the mechanisms and treatment of RVI-induced RV remodeling and dysfunction requires animal models to mimic the pathophysiology of RVI in patients. This study introduces a feasible procedure for RVI model generation in C57BL/6J mice. Further, this model was characterized based on the following: infarct size evaluation at 24 h after MI, assessment of cardiac remodeling and function with echocardiography, RV hemodynamics assessment, and histology of the infarct zone at 4 weeks after RVI. In addition, a coronary vasculature cast was performed to observe the coronary arterial arrangement in RV. This mouse model of RVI would facilitate the research on mechanisms of right heart failure and seek new therapeutic targets of RV remodeling.

There are several differences between the right and left ventricles. However, the pathophysiology of right ventricular infarction (RVI) has not been clarified. In the present protocol, a reproducible method for RVI mouse model generation is introduced, which may provide a means to explain the mechanism of RVI.

Right ventricular infarction (RVI) is a common presentation in clinical practice. Severe RVI can lead to fatal hemodynamic dysfunction and arrhythmia. In ...

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.

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