Name: left atrial stenosis induced pulmonary venous arterialization and group 2 pulmonary hypertension in rat
Uploaded: 2018-11-18T14:00:00
Description: Watch this Scientific Journal Video about Left Atrial Stenosis Induced Pulmonary Venous Arterialization and Group 2 Pulmonary Hypertension in Rat at JoVE.com

The authors acknowledge the Mitacs-Japan Society for the Promotion of Science (JSPS) Summer Program. Ping Yu Xiong was supported by funding from the Mitacs-JSPS Summer Program to visit the Jikei University School of Medicine. Dr. Minamisawa is supported in part by the Ministry of Education, Culture, Sports, Science and Technology of Japan (S.M.), the MEXT-Supported Program for the Strategic Research Foundation at Private Universities (S.M.), the Vehicle Racing Commemorative Foundation (S.M.), and The Jikei University Graduate Research Fund (S.M.) with financial support for this project. Dr. Archer is supported in part by U.S. National Institutes of Health (NIH) grants NIH 1R01HL113003-01A1 (S.L.A.) and NIH 2R01HL071115-08 (S.L.A.), the Canada Foundation for Innovation, Tier 1 Canada Research Chair in Mitochondrial Dynamics and Translational Medicine (S.L.A.), the William J. Henderson Foundation, the Canadian Vascular Network, and the Queen&#39;s Cardiopulmonary Unit (QCPU).
The authors acknowledge Mr. Tadashi Kokubo, Chief of Photographic Services of the Academic Information Center at the Jikei University School of Medicine, for filming the video.

The LAS experimental protocol has been approved by the Jikei University School of Medicine Animal Care Committee and the University Research and Ethics Committee (protocol #2015-118).
1. Pre-operative Preparation
<ol>
	<li>After arriving at the animal facility, provide 5-week-old male Sprague Dawley rats between 150 to 200 g with 1 week to acclimate to their new home prior to the operation.</li>
	<li>Prepare the following equipment before the surgery by autoclaving: 1) a small animal respira...

<ol>
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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=Prevalence+of+Pulmonary+Hypertension+in+the+General+Population:+The+Rotterdam+Study.">Prevalence of Pulmonary Hypertension in the General Population: The Rotterdam Study.</a> PLoS ONE. 10 (6), e0130072 (2015).</li><li>Wijeratne, D. 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=Increasing+Incidence+and+Prevalence+of+World+Health+Organization+Groups+1+to+4+Pulmonary+Hypertension:+A+Population-Based+Cohort+Study+in+Ontario,+Canada.">Increasing Incidence and Prevalence of World Health Organization Groups 1 to 4 Pulmonary Hypertension: A Population-Based Cohort Study in Ontario, Canada.</a> Circulation: Cardiovascular Quality and Outcomes. 11 (2), (2018).</li><li>Briongos Figuero, 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=Predictors+of+persistent+pulmonary+hypertension+after+mitral+valve+replacement.">Predictors of persistent pulmonary hypertension after mitral valve replacement.</a> Heart and Vessels. 31 (7), 1091-1099 (2016).</li><li>Jiang, B. H., Tardif, J. C., Shi, Y., Dupuis, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bosentan+does+not+improve+pulmonary+hypertension+and+lung+remodeling+in+heart+failure.">Bosentan does not improve pulmonary hypertension and lung remodeling in heart failure.</a> European Respiratory Society. 37 (3), 578-586 (2011).</li><li>Dayeh, N. 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J., Hadri, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pulmonary+hypertension+arising+from+left+heart+disease+causes+intrapulmonary+venous+arterialization+in+rats.">Pulmonary hypertension arising from left heart disease causes intrapulmonary venous arterialization in rats.</a> The Journal of Thoracic and Cardiovascular Surgery. 155 (1), 281-282 (2018).</li><li>Alsoufi, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Not+a+Cinderella+story.">Not a Cinderella story.</a> The Journal of Thoracic and Cardiovascular Surgery. 155 (1), 282-284 (2018).</li><li>Kato, 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=Pulmonary+vein+stenosis+and+the+pathophysiology+of+&amp;#34;upstream&amp;#34;+pulmonary+veins.">Pulmonary vein stenosis and the pathophysiology of &amp;#34;upstream&amp;#34; pulmonary veins.</a> The Journal of Thoracic and Cardiovascular Surgery. 148 (1), 245-253 (2014).</li></ol>

The LAS rat is a novel group 2 PH model that has already received substantial interest from researchers in the field12,13. Comparing to the two existing group 2 models, namely the pulmonary vein stenosis (PVS) model14, using piglets, and the supracoronary aortic banding (SAB) rat model8,9,10, the LAS rat model has several advantages. Compared to t...

The purpose of this article is to demonstrate the step-by-step procedure of how to perform the LAS surgery in rats. Surgically induced LAS closely mimics MS and cor triatriatum in humans, which involve the creation of a mechanical obstruction in the left atrium1. Obstruction of the left ventricular (LV) inflow often causes a congestion of the pulmonary venous circulation, and patients gradually develop PH. The World Health Organization classifies PH due to left heart diseases as group 2, which is the most prevalent group of PH2,3,4. The diagnosis of PH in patients with left heart diseases is associated with a greater than a sevenfold increase in the 1-year standardized mortality4. Currently, there is no approved therapy for group 2 PH apart from treating the underlying left heart diseases (e.g., surgically replacing the stenotic mitral valve). However, even effective mitral valve replacement does not resolve PH fully in up to half of the patients with MS5. This persistent PH is due to adverse pulmonary vascular remodeling, which is poorly understood. Hence, animal models are important to enhancing our understanding of the underlying molecular mechanisms of adverse pulmonary vascular remodeling in group 2 PH.
There are a few animal models of group 2 PH. Coronary artery ligation6,7 and transverse aortic banding8,9,10 in rodents are the most commonly used group 2 PH animal models. The major disadvantage of these models is the involvement of LV, which makes the outcome of group 2 PH studies difficult to interpret. In contrast, the LV remains intact in the LAS model. Furthermore, the LAS model is clinically relevant because it results in the slow and progressive development of PH over a 10-week period11. In humans, MS is considered significant if the transmitral Doppler flow velocity is greater than 2.0 m/s11, and we also use this number as a cut-off to determine whether the LAS surgery has produced significant stenosis. Furthermore, although the LAS model generates mild or moderate PH, it demonstrates characteristic histologic changes, similar to those in human patients, namely the development of intrapulmonary venous arterialization11. The LAS rat model is a novel and clinically relevant group 2 PH model with preserved LV function. It is suitable for studying the pathophysiology of persistent pulmonary vascular remodeling, identifying molecular targets, and testing novel therapies for group 2 PH.

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	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:159px;">5-0 Prolene Suture</td>
			<td style="width:132px;">Johnson &#38; Johnson - Ethicon</td>
			<td style="width:123px;">8725H</td>
			<td style="width:222px;">Polypropylene suture with HEMO-SEAL Technology</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:159px;">Anaesthesia Machine</td>
			<td style="width:132px;">Wakenyaku Co., Ltd.</td>
			<td style="width:123px;">BRTK-100A</td>
			<td>Air pump and anaethesia machine</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:159px;">Angiocatheter guidewire</td>
			<td style="width:132px;">Self-made</td>
			<td style="width:123px;"></td>
			<td>10 cm guidewire glued to a 1 cc syringe&#160;</td>
		</tr>
		<tr height="62">
			<td height="62" style="height:63px;width:159px;">Chest retractor</td>
			<td style="width:132px;">Natsume Seisakusho Co., Ltd.</td>
			<td style="width:123px;">F-2</td>
			<td></td>
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		<tr height="21">
			<td height="21" style="height:21px;width:159px;">Chest tube 23G</td>
			<td style="width:132px;">Self-made</td>
			<td style="width:123px;"></td>
			<td>10 cc syringe attached to a 23G needle plus plastic tube</td>
		</tr>
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			<td height="62" style="height:63px;width:159px;">Curved forceps</td>
			<td style="width:132px;">Natsume Seisakusho Co., Ltd.</td>
			<td style="width:123px;">A-14</td>
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			<td height="21" style="height:21px;width:159px;">Heating pad</td>
			<td style="width:132px;">Vivaria</td>
			<td style="width:123px;">MP-916-NV</td>
			<td>Keep body temperature at 37 degree celsius</td>
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		<tr height="21">
			<td height="21" style="height:21px;">Horizon Ligating Clips</td>
			<td style="width:132px;">Teleflex</td>
			<td style="width:123px;">REF 003200</td>
			<td>Size Medium-Large</td>
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			<td height="21" style="height:21px;">Horizon Manual-Load Ligating Clip Applier For Medium-Large Size Horizon</td>
			<td style="width:132px;">Teleflex</td>
			<td>REF 337085</td>
			<td>Ligation Clips Angled Jaw, (20cm)</td>
		</tr>
		<tr height="62">
			<td height="62" style="height:63px;width:159px;">Needle holder</td>
			<td style="width:132px;">Natsume Seisakusho Co., Ltd.</td>
			<td style="width:123px;">MC-40</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:159px;">Rodent Respirator</td>
			<td style="width:132px;">CWE Inc</td>
			<td style="width:123px;">SAR-830/P</td>
			<td>Small animal ventilator</td>
		</tr>
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			<td height="62" style="height:63px;width:159px;">Scissors</td>
			<td style="width:132px;">Natsume Seisakusho Co., Ltd.</td>
			<td style="width:123px;">B-12</td>
			<td>Straight scissors ideally with round tips</td>
		</tr>
		<tr height="62">
			<td height="62" style="height:63px;width:159px;">Straight forceps</td>
			<td style="width:132px;">Natsume Seisakusho Co., Ltd.</td>
			<td style="width:123px;">A-7</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:159px;">Tongue depressor</td>
			<td style="width:132px;">Uchida Yoko Co., Ltd.</td>
			<td style="width:123px;">8-615-2417</td>
			<td>Use the wide end</td>
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</table>

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.

The effectiveness of the LAS is confirmed using echocardiography, 2 weeks postoperative. Rats with an LV inflow velocity greater than 2.0 m/s, measured with a four-chamber view, are considered to have developed significant stenosis (Figure 1) and reliably develop moderate PH and pulmonary venous arterialization 8 - 10 weeks post-LAS surgery.
Ten weeks post-LAS surgery, the rats in the LAS group show...

Watch this Scientific Journal Video about Left Atrial Stenosis Induced Pulmonary Venous Arterialization and Group 2 Pulmonary Hypertension in Rat at JoVE.com

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

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 ...

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