Name: echocardiographic assessment of the right heart in mice
Uploaded: 2013-11-27T21:00:00
Description: Watch this Scientific Journal Video about Echocardiographic Assessment of the Right Heart in Mice at JoVE.com

1. Equipment Preparation&#160;
<ol>
	<li>Examine the ultrasound transducer for defects. Depending on the equipment used, this step may be unnecessary.
	<ol>
		<li>If an air bubble is observed, remove the screw located on the right side of the transducer head, and add sterile water through the hole with a 26 G needle. Air bubbles inside the transducer head are common. They will impede the acquisition of quality images.</li>
		<li>Check the membrane covering the probe for leaks or holes. Replace if necessary.</li>
	</ol>...

<ol>
	<li>Urboniene, D., Haber, I., Fang, Y. H., Thenappan, T., Archer, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Validation+of+high-resolution+echocardiography+and+magnetic+resonance+imaging+vs.+high-fidelity+catheterization+in+experimental+pulmonary+hypertension.">Validation of high-resolution echocardiography and magnetic resonance imaging vs. high-fidelity catheterization in experimental pulmonary hypertension.</a> Am. J. Physiol. Lung Cell Mol. Physiol. 299, 401-412 (2010).</li><li>Rottman, J. N., Ni, G., Brown, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Echocardiographic+evaluation+of+ventricular+function+in+mice.">Echocardiographic evaluation of ventricular function in mice.</a> Echocardiography. 24, 83-89 (2007).</li><li>West, 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=Pulmonary+hypertension+in+transgenic+mice+expressing+a+dominant-negative+BMPRII+gene+in+smooth+muscle.">Pulmonary hypertension in transgenic mice expressing a dominant-negative BMPRII gene in smooth muscle.</a> Circ. Res. 94, 1109-1114 (2004).</li><li>Ghofrani, H. A., Seeger, W., Grimminger, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Imatinib+for+the+treatment+of+pulmonary+arterial+hypertension.">Imatinib for the treatment of pulmonary arterial hypertension.</a> N. Engl. J. Med. 353, 1412-1413 (2005).</li><li>Gomberg-Maitland, 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=A+dosing/cross-development+study+of+the+multikinase+inhibitor+sorafenib+in+patients+with+pulmonary+arterial+hypertension.">A dosing/cross-development study of the multikinase inhibitor sorafenib in patients with pulmonary arterial hypertension.</a> Clin. Pharmacol. Ther. 87, 303-310 (2010).</li><li>Brittain, E., 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+plasticity+and+functional+imaging.">Right ventricular plasticity and functional imaging.</a> Pulm. Circ. 2, 309-326 (2012).</li><li>Yang, X. 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=Echocardiographic+assessment+of+cardiac+function+in+conscious+and+anesthetized+mice.">Echocardiographic assessment of cardiac function in conscious and anesthetized mice.</a> Am. J. Physiol. 277, 1967-1974 (1999).</li><li>Suehiro, K., 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=Assessment+of+segmental+wall+motion+abnormalities+using+contrast+two-dimensional+echocardiography+in+awake+mice.">Assessment of segmental wall motion abnormalities using contrast two-dimensional echocardiography in awake mice.</a> Am. J. Physiol. Heart Circ Physiol. 280, 1729-1735 (2001).</li><li>Jones, J. E., 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=Serial+noninvasive+assessment+of+progressive+pulmonary+hypertension+in+a+rat+model.">Serial noninvasive assessment of progressive pulmonary hypertension in a rat model.</a> Am. J. Physiol. Heart Circ. Physiol. 283, 364-371 (2002).</li><li>Devaraj, 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=Detection+of+pulmonary+hypertension+with+multidetector+CT+and+echocardiography+alone+and+in+combination.">Detection of pulmonary hypertension with multidetector CT and echocardiography alone and in combination.</a> Radiology. 254, 609-616 (2010).</li><li>Kitabatake, 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=Noninvasive+evaluation+of+pulmonary+hypertension+by+a+pulsed+Doppler+technique.">Noninvasive evaluation of pulmonary hypertension by a pulsed Doppler technique.</a> Circulation. 68, 302-309 (1983).</li><li>Yared, K., 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+artery+acceleration+time+provides+an+accurate+estimate+of+systolic+pulmonary+arterial+pressure+during+transthoracic+echocardiography.">Pulmonary artery acceleration time provides an accurate estimate of systolic pulmonary arterial pressure during transthoracic echocardiography.</a> J. Am. Soc. Echocardiogr. 24, 687-692 (2011).</li><li>Cheung, M. 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=Body+surface+area+prediction+in+normal,+hypermuscular,+and+obese+mice.">Body surface area prediction in normal, hypermuscular, and obese mice.</a> J. Surg. Res. 153, 326-331 (2009).</li><li>Patten, R. D., Hall-Porter, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small+animal+models+of+heart+failure:+development+of+novel+therapies,+past+and+present.">Small animal models of heart failure: development of novel therapies, past and present.</a> Circ. Heart Fail. 2, 138-144 (2009).</li><li>Baumgartner, 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=Echocardiographic+assessment+of+valve+stenosis:+EAE/ASE+recommendations+for+clinical+practice.">Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice.</a> J. Am. Soc. Echocardiogr. 22, 1-23 (2009).</li><li>Arkles, J. 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=Shape+of+the+right+ventricular+Doppler+envelope+predicts+hemodynamics+and+right+heart+function+in+pulmonary+hypertension.">Shape of the right ventricular Doppler envelope predicts hemodynamics and right heart function in pulmonary hypertension.</a> Am. J. Respir. Crit. Care Med. 183, 268-276 (2011).</li><li>Wiesmann, F., 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=Analysis+of+right+ventricular+function+in+healthy+mice+and+a+murine+model+of+heart+failure+by+in+vivo+MRI.">Analysis of right ventricular function in healthy mice and a murine model of heart failure by in vivo MRI.</a> Am. J. Physiol. Heart Circ. Physiol. 283, 1065-1071 (2002).</li><li>West, 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=A+potential+role+for+Insulin+resistance+in+experimental+pulmonary+hypertension.">A potential role for Insulin resistance in experimental pulmonary hypertension.</a> Eur. Respir. J. , (2012).</li><li>Johnson, J. 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=Cytoskeletal+defects+in+Bmpr2-associated+pulmonary+arterial+hypertension.">Cytoskeletal defects in Bmpr2-associated pulmonary arterial hypertension.</a> Am. J. Physiol. Lung Cell Mol. Physiol. 302, L474-L484 (2012).</li><li>Johnson, J. A., West, J., Maynard, K. B., Hemnes, A. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ACE2+improves+right+ventricular+function+in+a+pressure+overload+model.">ACE2 improves right ventricular function in a pressure overload model.</a> PLoS One. 6, e20828 (2011).</li></ol>

Mouse models of disease, either transgenic or toxin-related, require phenotypic validation that the model actually recapitulates the human disease it is intended to emulate. This validation can often be accomplished by the presence or absence of a particular feature, for example development of a tumor. However, models that result in hemodynamic abnormalities such as aortic constriction models of left ventricular hypertrophy or our transgenic model of PAH are more difficult to validate. These models require either termina...

Elevated pulmonary pressure and right ventricular (RV) dysfunction are the hallmarks of pulmonary vascular disease in animal models and human patients with pulmonary arterial hypertension (PAH). Transgenic and toxic (e.g. monocrotaline or hypoxia) models of 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.
Echocardiography is the mainstay of the noninvasive assessment of ventricular function in rodent models1,2. Echocardiography has the advantage of clear translation to humans in whom the same tool is used. In addition, some genetic models exhibit incomplete penetrance3; the ability to noninvasively identify affected animals saves valuable time and resources. Noninvasive assessment of disease severity without sacrificing an animal also allows researchers to serially study the effects of investigative therapies. This is especially important given the rapidity with which translational therapies can progress to human trials4,5.
In humans, echocardiographic assessment of RV size and pulmonary hypertension is particularly challenging due to the retrosternal position and irregular shape of the RV6. Rodent models have the added challenges of small size and extremely rapid heart rates (300-700 beat/min). Recent advances including higher frame rates and smaller transducers have improved image quality and even allowed conscious imaging in some experimental protocols, though most rodent imaging is done under anesthesia7,8. Excellent experimental protocols of echocardiography in rat models of PAH have been described and validated against both MRI and invasive hemodynamics1,9. However, 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 and a model of isolated RV afterload after pulmonary artery banding; however, this protocol is applicable to any diseases affecting the pulmonary vasculature or right heart. We will describe animal preparation and detailed assessment of RV size and function as well as main pulmonary artery (PA) size. We also demonstrate the techniques and calculations needed to estimate stroke volume and cardiac output. Technical limitations preclude accurate Doppler estimates of pulmonary pressure, but we have applied a well-validated human surrogate, pulmonary artery acceleration time, to estimate PA pressure.

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			<td height="55" style="height:55px;width:251px;">Vevo 770 High Resolution Micro-Ultrasound System</td>
			<td style="width:164px;">Visualsonics Inc.</td>
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			<td height="66" style="height:66px;width:251px;">RMV (Real-Time MicroVisualization) 704B 40 mH Scanhead w/ Encapsulated Transducer</td>
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			<td style="width:247px;">get more info at www.visualsonics.com/products</td>
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			<td height="64" style="height:64px;width:251px;">Computer Mouse set up for use with the Vevo770</td>
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			<td height="86" style="height:86px;width:251px;">VetEquip Portable Tabletop Anesthesia Machine with an Isoflurane Vaporizer</td>
			<td style="width:164px;">VetEquip</td>
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			<td style="width:188px;">1527-0</td>
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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.

The principal goals of this protocol are to quantify RV size and function, and to understand the degree to which the pulmonary vasculature is diseased. Appropriate preparation of both the mouse and echocardiography equipment is essential to obtaining accurate and reproducible results. Mice should have their chest depilated and limbs secured to the imaging platform with tape. Anesthesia, in this case isoflurane, is administered via nose cone. The transducer should be checked for defects, particularly air bubbles, which ca...

Watch this Scientific Journal Video about Echocardiographic Assessment of the Right Heart in Mice at JoVE.com

Echocardiographic Assessment of the Right Heart in Mice

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 ...

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