Name: invasive hemodynamic assessment for the right ventricular system and hypoxia-induced pulmonary arterial hypertension in mice
Uploaded: 2019-10-24T13:30:00
Description: Watch this Scientific Journal Video about Invasive Hemodynamic Assessment for the Right Ventricular System and Hypoxia-Induced Pulmonary Arterial Hypertension in Mice at JoVE.com

This research is supported by the Postgraduate Education and Teaching Reform Project of Peking Union Medical College (10023-2016-002-03), the Fuwai Hospital Youth Fund (2018-F09), and the Director Fund of Beijing Key Laboratory of Pre-clinical Research and Evaluation for Cardiovascular Implant Materials (2018-PT2-ZR05).

The animal protocol was reviewed and approved by the Institutional Animal Care and Use Committee at Fuwai Hospital, Chinese Academy of Medical Science, Peking Union Medical College (NO.0000287). The experimental animals were housed and fed according to the guidelines of animal welfare in China.
NOTE: Eight- to 12-week-old male C57BL mice were housed in an environment with a 12 h dark/ 12 h light cycle. The PAH mice were housed for 4 weeks under an oxygen concentration of 10%, maintained by an ...

<ol>
	<li>Humbert, 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=Advances+in+therapeutic+interventions+for+patients+with+pulmonary+arterial+hypertension.">Advances in therapeutic interventions for patients with pulmonary arterial hypertension.</a> Circulation. 130 (24), 2189-2208 (2014).</li><li>Chatterjee, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Swan-Ganz+catheters:+past,+present,+and+future:+a+viewpoint.">The Swan-Ganz catheters: past, present, and future: a viewpoint.</a> Circulation. 119 (1), 147-152 (2009).</li><li>Adamson, P. 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=CHAMPION+trial+rationale+and+design:+the+long-term+safety+and+clinical+efficacy+of+a+wireless+pulmonary+artery+pressure+monitoring+system.">CHAMPION trial rationale and design: the long-term safety and clinical efficacy of a wireless pulmonary artery pressure monitoring system.</a> Journal of Cardiac Failure. 17 (1), 3-10 (2011).</li><li>Abraham, W. T., 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=Wireless+pulmonary+artery+haemodynamic+monitoring+in+chronic+heart+failure:+a+randomised+controlled+trial.">Wireless pulmonary artery haemodynamic monitoring in chronic heart failure: a randomised controlled trial.</a> The Lancet. 377 (9766), 658-666 (2011).</li><li>Adamson, P. 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=Wireless+pulmonary+artery+pressure+monitoring+guides+management+to+reduce+decompensation+in+heart+failure+with+preserved+ejection+fraction.">Wireless pulmonary artery pressure monitoring guides management to reduce decompensation in heart failure with preserved ejection fraction.</a> Circulation: Heart Failure. 7 (6), 935-944 (2014).</li><li>Shatat, 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=Endothelial+Kruppel-like+Factor+4+modulates+pulmonary+arterial+hypertension.">Endothelial Kruppel-like Factor 4 modulates pulmonary arterial hypertension.</a> American Journal of Respiratory Cell and Molecular Biology. 50 (3), 647-653 (2014).</li><li>. SPR-1000 Mouse Pressure Catheter Available from: <a target="_blank" href="https://millar.com/products/research/pressure/single-pressure-no-lumen/spr-1000">https://millar.com/products/research/pressure/single-pressure-no-lumen/spr-1000</a> (2019)</li><li>Tabima, D. M., Hacker, T. A., Chesler, N. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+right+ventricular+function+in+the+normal+and+hypertensive+mouse+hearts+using+admittance-derived+pressure-volume+loops.">Measuring right ventricular function in the normal and hypertensive mouse hearts using admittance-derived pressure-volume loops.</a> American Journal of Physiology Heart and Circulatory Physiology. 299 (6), 2069-2075 (2010).</li><li>Skuli, N., 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=Endothelial+deletion+of+hypoxia-inducible+factor-2alpha+(HIF-2alpha)+alters+vascular+function+and+tumor+angiogenesis.">Endothelial deletion of hypoxia-inducible factor-2alpha (HIF-2alpha) alters vascular function and tumor angiogenesis.</a> Blood. 114 (2), 469-477 (2009).</li><li>. LabChart Available from: <a target="_blank" href="https://www.adinstruments.com/products/labchart?creative=290739105773_keyword=labchart_matchtype=e_network=g_device=c_gclid=CjwKCAjwxrzoBRBBEiwAbtX1n42I2S06KmccVncUHkmExU8KKOXXREyzx8bvTrxYMSze-ooE0atcbRoCliwQAvD_BwE">https://www.adinstruments.com/products/labchart?creative=290739105773_keyword=labchart_matchtype=e_network=g_device=c_gclid=CjwKCAjwxrzoBRBBEiwAbtX1n42I2S06KmccVncUHkmExU8KKOXXREyzx8bvTrxYMSze-ooE0atcbRoCliwQAvD_BwE</a> (2019)</li><li>Marius, M. H., 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=Definitions+and+diagnosis+of+pulmonary+hypertension.">Definitions and diagnosis of pulmonary hypertension.</a> Journal of the American College of Cardiology. 62 (25), 42-50 (2013).</li><li>Ciuclan, 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=A+novel+murine+model+of+severe+pulmonary+arterial+hypertension.">A novel murine model of severe pulmonary arterial hypertension.</a> American Journal of Respiratory and Critical Care Medicine. 184 (10), 1171-1182 (2011).</li><li>Brown, R. H., Walters, D. M., Greenberg, R. S., Mitzner, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+of+endotracheal+intubation+and+pulmonary+functional+assessment+for+repeated+studies+in+mice.">A method of endotracheal intubation and pulmonary functional assessment for repeated studies in mice.</a> Journal of Applied Physiology. 87 (6), 2362-2365 (1999).</li><li>Chen, W. C., 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+systolic+pressure+measurements+in+combination+with+harvest+of+lung+and+immune+tissue+samples+in+mice.">Right ventricular systolic pressure measurements in combination with harvest of lung and immune tissue samples in mice.</a> Journal of Visualized Experiments. (71), 50023 (2013).</li><li>Ma, Z., Mao, L., Rajagopal, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemodynamic+characterization+of+rodent+models+of+pulmonary+arterial+hypertension.">Hemodynamic characterization of rodent models of pulmonary arterial hypertension.</a> Journal of Visualized Experiments. (110), 53335 (2016).</li><li>Chen, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Berberine+attenuates+hypoxia-induced+pulmonary+arterial+hypertension+via+bone+morphogenetic+protein+and+transforming+growth+factor-&#946;+signaling.">Berberine attenuates hypoxia-induced pulmonary arterial hypertension via bone morphogenetic protein and transforming growth factor-&#946; signaling.</a> Journal of Cellular Physiology. , (2019).</li><li>Bueno-Beti, C., Hadri, L., Hajjar, R. J., Sassi, Y., Ishikawa, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Sugen+5416/Hypoxia+mouse+model+of+pulmonary+arterial+hypertension.">The Sugen 5416/Hypoxia mouse model of pulmonary arterial hypertension.</a> Experimental Models of Cardiovascular Diseases. Methods in Molecular Biology. vol 1816. , (2018).</li></ol>

Tracheal intubation is the first important step for open-chest surgeries. The classic method of tracheal intubation for small animals, such as rats or mice, involves making a T-shaped incision on the trachea and directly inserting Y-type tracheal tubing into the trachea. In practice, we find that this method is not easy during operation. The Y-type tracheal tubing is too large for small animals and forms an angle with the trachea. Thus, it is difficult to fix the tubing in place. Additionally, once the intubation tubing ...

Pulmonary arterial hypertension (PAH) is a chronic and severe cardiopulmonary disorder with elevation in pulmonary artery pressure (PAP) and right ventricular pressure (RVP) that is caused by cellular proliferation and fibrosis of small pulmonary arteries1. Pulmonary artery catheters, also called Swan-Ganz catheters2, are commonly used in the clinical monitoring of RVP and PAP. Furthermore, a wireless PAP monitoring system has been used clinically3,4,5. To mimic the disease for study in mice, a hypoxic environment is used to simulate human clinical manifestations of PAH6. In the evaluation of PAP in animals, large animals are relatively easy to monitor through pulmonary artery catheters using the same technique as for human subjects, but small animals such as rats and mice are difficult to assess because of their small body size. Hemodynamic measurement of the right ventricular system in mice is possible with an ultrasmall size 1 Fr catheter7. A method for measuring RVP and PAP in mice has been reported in the literature8,9, but the methodology lacks a detailed description. RVP and PAP are more challenging to measure than left ventricular pressure because of the anatomical differences between the left and right heart systems.
To get both PAP and RVP parameters in the same mouse, we describe an open-chest surgery-based approach for right heart hemodynamic measurements, its validation with healthy and PAH mice, and how to avoid generating artificial data during the complicated open-chest surgery. Although this technique is best performed by a well-trained surgeon, it has the advantage of being able to assess PAP and RVP in the same mouse.

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	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">2,2,2-Tribromoethanol</td>
			<td style="width:192px;">Sigma-Aldrich</td>
			<td style="width:157px;">T48402-5G</td>
			<td style="width:183px;">For anesthesia</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Animal temperature controller</td>
			<td style="width:192px;">Physitemp Instruments, Inc.</td>
			<td style="width:157px;">TCAT-2LV</td>
			<td style="width:183px;">For temperature control</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Dissection forceps</td>
			<td style="width:192px;">Fine Science Tools, Inc.</td>
			<td style="width:157px;">11274-20</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Gemini Cautery System</td>
			<td style="width:192px;">Gemini</td>
			<td style="width:157px;">GEM 5917</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Intravenous catheter (22G)</td>
			<td style="width:192px;">BD angiocath</td>
			<td style="width:157px;">381123</td>
			<td style="width:183px;">For intubation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">LabChart 7.3</td>
			<td style="width:192px;">ADInstruments</td>
			<td style="width:157px;"></td>
			<td style="width:183px;">For data analysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Light illumination system</td>
			<td style="width:192px;">Olympus</td>
			<td style="width:157px;"></td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Mikro-Tip catheter</td>
			<td style="width:192px;">Millar Instruments, Houston, TX</td>
			<td style="width:157px;">SPR-1000</td>
			<td style="width:183px;">For pressure measurement</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Millar Pressure-Volume Systems</td>
			<td style="width:192px;">Millar Instruments, Houston, TX</td>
			<td style="width:157px;">MVPS-300</td>
			<td style="width:183px;">For pressure measurement</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">O2 Controller and Hypoxia chamber</td>
			<td style="width:192px;">Biospherix</td>
			<td style="width:157px;">ProOx 110</td>
			<td style="width:183px;">For chronic hypoxia</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">PowerLab Data Acquisition System</td>
			<td style="width:192px;">ADInstruments</td>
			<td style="width:157px;">PowerLab 16/30</td>
			<td style="width:183px;">For data recording</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Scissors</td>
			<td style="width:192px;">Fine Science Tools, Inc.</td>
			<td style="width:157px;">14084-08</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Small animal ventilator</td>
			<td style="width:192px;">Harvard Apparatus</td>
			<td style="width:157px;">Mini-Vent 845</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Stereomicroscope</td>
			<td style="width:192px;">Olympus</td>
			<td style="width:157px;">SZ61</td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Surgery tape</td>
			<td style="width:192px;">3M</td>
			<td style="width:157px;"></td>
			<td style="width:183px;">For surgery</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Terg-a-zyme enzyme</td>
			<td style="width:192px;">Sigma-Aldrich</td>
			<td style="width:157px;">Z273287-1EA</td>
			<td style="width:183px;">For catheter cleaning</td>
		</tr>
	</tbody>
</table>

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.

The pressure transducer catheter was inserted into the right ventricle (Figure 3A) through a tunnel expanded by a 25 G needle, and a typical RVP waveform (Figure 3C) was obtained. The catheter was continually adjusted and slowly advanced and kept in the same axis as the pulmonary artery while passing through the pulmonary valve (Figure 3B). When the pressure sensor was successfully ...

Watch this Scientific Journal Video about Invasive Hemodynamic Assessment for the Right Ventricular System and Hypoxia-Induced Pulmonary Arterial Hypertension in Mice at JoVE.com

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

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. ...

This protocol is an open chest surgery based hemodynamic assessment and it is useful for the right ventricular and pulmonary artery pressure evaluation in small animals such as mice. The advantage of this procedure is that it can generate both VP and PAP parameters at the same time. So it is preferable for evaluations of PAH models.Begin by setting up the equipment for surgery. Soak the pressure transducer catheter in 0.9%saline at room temperature for at least 30 minutes before the hemodynamic experiment. Then, connect the catheter to a pressure volume system.Calibrate the pressure transducer by turning the calibration knob to zero and 25 millimeters of mercury to send a verification pressure signal to the data acquisition software, then configure the calibration setting. Turn the knob to transducer, and adjust the balance valve to zero baseline. Set up a standard stereo microscope, temperature controlled small animal surgical table, and a light illumination system for microsurgery.Once the mouse is properly anesthetized, remove the chest and neck fur using a shaver and hair removal lotion. Secure the mouse in the supine position on the temperature controlled surgical table. After ensuring that the anesthesia is in effect, make a midline incision on the neck skin.Dissect the skeletal muscle using curved forceps and expose the trachea. Perform intubation through the mouth with a 22 gauge intravenous sheath catheter, confirming that the tubing is in the trachea with forceps. Connect the tubing to a small animal ventilator and secure it for ventilation using tape.Then, make a midline incision on the chest skin and carefully dissect the chest muscle using a cautery tool. Cut the sternum using scissors across the middle, and expose the thoracic cavity. Make sure to prevent any bleeding using the cautery tool.Expose the right ventricle with retractors, then insert the saline soaked pressure transducer catheter through a small tunnel created with a 25 gauge needle into the right ventricle to measure right ventricular pressure, or RVP. Hold the catheter cable and cross the pulmonary valve in a coaxial manner with the pulmonary artery. Observe the pressure waveform, and obtain a stable pulmonary artery pressure or PAP signal.Next, record the hemodynamic data using the data acquisition software. Carefully remove the catheter from the right heart system and place it into a one milliliter syringe containing 1%digestive enzyme solution. This protocol was successfully used to obtain RVP and PAP waveforms in mice by inserting a pressure transducer catheter into the right ventricle and the pulmonary artery.In order to avoid generating artificial data, segments with noise were excluded from the data analysis and corrections were made if the zero level of the catheter had drifted. RVP and PAP were measured in mice with induced chronic hypoxia, and the results were compared to those obtained from a control group. Systolic PAP, diastolic PAP, mean PAP, and right ventricular systolic pressure were all significantly increased in the chronic hypoxia group.The most important thing to remember is to insert the pressure transducer catheter into the right ventricle carefully, making sure to avoid damage to the catheter and confirm the smooth RVP waveform appears on the screen.

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Research

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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. ...

Hemodynamic Characterization of Rodent Models of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle proliferation and obliteration of pulmonary arterioles. This in turn results in right ventricular (RV) failure, with significant morbidity and mortality. Rodent models of PAH, in the mouse and the rat, are important for understanding the pathophysiology underlying this rare disease. Notably, different models of PAH may be associated with different degrees of pulmonary hypertension, RV hypertrophy and RV failure. Therefore, a complete hemodynamic characterization of mice and rats with PAH is critical in determining the effects of drugs or genetic modifications on the disease. 
Here we demonstrate standard procedures for assessment of right ventricular function and hemodynamics in both rat and mouse PAH models. Echocardiography is useful in determining RV function in rats, although obtaining standard views of the right ventricle is challenging in the awake mouse. Access for right heart catheterization is obtained by the internal jugular vein in closed-chest mice and rats. Pressures can be measured using polyethylene tubing with a fluid pressure transducer or a miniature micromanometer pressure catheter. Pressure-volume loop analysis can be performed in the open chest. After obtaining hemodynamics, the rodent is euthanized. The heart can be dissected to separate the RV free wall from the left ventricle (LV) and septum, allowing an assessment of RV hypertrophy using the Fulton index (RV/(LV+S)). Then samples can be harvested from the heart, lungs and other tissues as needed.

Pulmonary arterial hypertension (PAH) is a disease of pulmonary arterioles that leads to their obliteration and the development of right ventricular failure. Rodent models of PAH are critical in understanding the pathophysiology of PAH. Here we demonstrate hemodynamic characterization, with right heart catheterization and echocardiography, in the mouse and rat.

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle ...

Shunt Surgery, Right Heart Catheterization, and Vascular Morphometry in a Rat Model for Flow-induced Pulmonary Arterial Hypertension

In this protocol, PAH is induced by combining a 60 mg/kg monocrotalin (MCT) injection with increased pulmonary blood flow through an aorto-caval shunt (MCT+Flow). The shunt is created by inserting an 18-G needle from the abdominal aorta into the adjacent caval vein. Increased pulmonary flow has been demonstrated as an essential trigger for a severe form of PAH with distinct phases of disease progression, characterized by early medial hypertrophy followed by neointimal lesions and the progressive occlusion of the small pulmonary vessels. To measure the right heart and pulmonary hemodynamics in this model, right heart catheterization is performed by inserting a rigid cannula containing a flexible ball-tip catheter via the right jugular vein into the right ventricle. The catheter is then advanced into the main and the more distal pulmonary arteries. The histopathology of the pulmonary vasculature is assessed qualitatively, by scoring the pre- and intra-acinar vessels on the degree of muscularization and the presence of a neointima, and quantitatively, by measuring the wall thickness, the wall-lumen ratios, and the occlusion score.

This protocol describes a surgical procedure to create a model for flow-induced pulmonary arterial hypertension (PAH) in rats and the procedures to analyze the principle hemodynamic and histological end-points in this model.

In this protocol, PAH is induced by combining a 60 mg/kg monocrotalin (MCT) injection with increased pulmonary blood flow through an aorto-caval shunt ...

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.

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 ...

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 ...

Non-invasive Assessment of Dorsiflexor Muscle Function in Mice

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively affect skeletal muscle. This can result in a loss of muscle mass (atrophy) and/or loss of muscle quality (reduced force per unit of muscle mass), both of which are prevalent in chronic disease, muscle-specific disease, immobilization, and aging (sarcopenia). Skeletal muscle function in animals can be evaluated by a range of different tests. All tests have limitations related to the physiological testing environment, and the selection of a specific test often depends on the nature of the experiments. Here, we describe an in vivo, non-invasive technique involving a helpful and easy assessment of force frequency-curve (FFC) in mice that can be performed on the same animal over time. This permits monitoring of disease progression and/or efficacy&#160;of a potential therapeutic treatment.

Measurement of rodent skeletal muscle contractile function is a useful tool that can be used to track disease progression as well as efficacy of therapeutic intervention. We describe here the non-invasive, in vivo assessment of the dorsiflexor muscles that can be repeated over time in the same mouse.

Assessment of skeletal muscle contractile function is an important measurement for both clinical and research purposes. Numerous conditions can negatively ...

Left Atrial Stenosis Induced Pulmonary Venous Arterialization and Group 2 Pulmonary Hypertension in Rat

The mechanism of mitral stenosis-induced pulmonary venous arterialization and group 2 pulmonary hypertension (PH) is unclear. There is no rodent model of group 2 PH, due to mitral stenosis (MS), to facilitate the investigation of disease mechanisms and potential therapeutic strategies. We present a novel rat model of pulmonary venous congestion-induced pulmonary venous arterialization and group 2 PH caused by left atrial stenosis (LAS). LAS is achieved by constricting the left atrium using a half-closed titanium clip. After the LAS surgery, a rat model with a transmitral inflow velocity greater than or equal to 2.0 m/s on echocardiography gradually develops pulmonary venous arterialization and group 2 PH over an 8- to 10-week period. In this protocol, we provide the step-by-step procedure of how to perform the LAS surgery. The presented LAS rat model mimics MS in humans and is useful for studying the underlying molecular mechanism of pulmonary venous arterialization and for the preclinical evaluation of therapies for group 2 PH.

Left atrial stenosis (LAS) is a novel surgical technique used for studying group 2 pulmonary hypertension (PH) and mechanisms underlying pulmonary venous arterialization. Here, we present a protocol to constrict the left atrium using a titanium clip to cause pulmonary venous arterialization and moderate PH in a rat.

The mechanism of mitral stenosis-induced pulmonary venous arterialization and group 2 pulmonary hypertension (PH) is unclear. There is no rodent model of ...

Induction and Characterization of Pulmonary Hypertension in Mice using the Hypoxia/SU5416 Model

Pulmonary Hypertension (PH) is a pathophysiological condition, defined by a mean pulmonary arterial pressure exceeding 25 mm Hg at rest, as assessed by right heart&#160;catheterization. A broad spectrum of diseases can lead to PH, differing in their etiology, histopathology, clinical presentation, prognosis, and response to&#160;treatment. Despite significant progress in the last years, PH remains an uncured disease. Understanding the underlying mechanisms can pave the way for the development of new therapies. Animal models are important research tools to achieve this goal. Currently, there are several models available for recapitulating PH. This protocol describes a two-hit mouse PH model. The stimuli for PH development are hypoxia and the injection of SU5416, a vascular endothelial growth factor (VEGF) receptor antagonist. Three weeks after initiation of Hypoxia/SU5416, animals develop pulmonary vascular remodeling imitating the histopathological changes observed in human PH (predominantly Group 1). Vascular remodeling in the pulmonary circulation results in the remodeling of the right&#160;ventricle (RV). The procedures for measuring RV pressures (using the open chest method), the morphometrical analyses of the RV (by dissecting and weighing both cardiac ventricles) and the histological assessments of the remodeling (both pulmonary by assessing vascular remodeling and cardiac by assessing RV cardiomyocyte hypertrophy and fibrosis) are described in detail. The advantages of this protocol are the possibility of the application both in wild type and in genetically modified mice, the relatively easy and low-cost implementation, and the quick development of the disease of interest (3 weeks). Limitations of this method are that mice do not develop a severe phenotype and PH is reversible upon return to normoxia. Prevention, as well as therapy studies, can easily be implemented in this model, without the necessity of advanced skills (as opposed to surgical rodent models).

This protocol describes the induction of pulmonary hypertension (PH) in mice based on the exposure to hypoxia and the injection of a VEGF receptor antagonist. The animals develop PH and right ventricular (RV) hypertrophy 3 weeks after the initiation of the protocol. The functional and morphometrical characterization of the model is also presented.

Pulmonary Hypertension (PH) is a pathophysiological condition, defined by a mean pulmonary arterial pressure exceeding 25 mm Hg at rest, as assessed by ...