Name: echocardiographic approaches and protocols for comprehensive phenotypic characterization of valvular heart disease in mice
Uploaded: 2017-02-14T12:30:00
Description: Watch this Scientific Journal Video about Echocardiographic Approaches and Protocols for Comprehensive Phenotypic Characterization of Valvular Heart Disease in Mice at JoVE.com

This work was supported by NIH grants HL111121 (JDM) and TR000954 (JDM).

1. Prepare the Materials and Equipment (Table 1 and Figure 1)
<ol>
	<li>Turn on the ultrasound machine. Enter the animal ID, date, and time (for serial imaging experiments) and other relevant information.</li>
	<li>Use a high-frequency ultrasound transducer, 40 MHz for imaging mice less than ~20 g or 30 MHz for mice greater than ~20 g.</li>
	<li>Connect the platform to the electrocardiogram (ECG) monitor for ECG gating of imaging for certain modalities. 
	NOTE: Critically, this also allows for the instantaneous ca...

<ol>
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O., 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=Focused+update+incorporated+into+the+ACC/AHA+2006+guidelines+for+the+management+of+patients+with+valvular+heart+disease:+a+report+of+the+American+College+of+Cardiology/American+Heart+Association+Task+Force+on+Practice+Guidelines+(Writing+Committee+to+Revise+the+1998+Guidelines+for+the+Management+of+Patients+With+Valvular+Heart+Disease):+endorsed+by+the+Society+of+Cardiovascular+Anesthesiologists,+Society+for+Cardiovascular+Angiography+and+Interventions,+and+Society+of+Thoracic+Surgeons.">Focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients With Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons.</a> Circulation. 118, e523-e661 (2008).</li><li>Yutzey, K. 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Induction of anesthesia
Proper induction and maintenance of anesthesia is critical for the accurate assessment of changes in heart valve and cardiac function in mice. Given the rapid induction of anesthesia elicited by isoflurane and the relatively long wash-out time of this anesthetic following deep anesthesia, we do not use a stand-alone anesthesia chamber for induction. Instead, as noted in detail above, animals are guided directly to the anesthesia cone, which allows for rapi...

Aging is associated with progressive increases in cardiovascular calcification1. Hemodynamically significant aortic valve stenosis affects 3% of the population over the age of 652, and patients with even moderate aortic valve stenosis (peak velocity of 3-4 m/s) have a 5 year event-free survival of less than 40%3. Presently, there are no effective treatments to slow the progression of aortic valve calcification, and surgical aortic valve replacement is the only available treatment for advanced aortic valve stenosis4.
Studies aimed at gaining a deeper understanding of the mechanisms that contribute to the initiation and progression of aortic valve calcification are a key first step in moving towards pharmacological and non-surgical methods to manage aortic valve stenosis5,6. Genetically-altered mice have played a major role in developing our understanding of the mechanisms that contribute to a variety of diseases and are now coming to the forefront of mechanistic studies aimed at understanding the biology of aortic valve stenosis6,7,8. Unlike other cardiovascular diseases such as atherosclerosis and heart failure-where standard protocols for evaluating vascular and ventricular function are for the most part well-established-there are unique challenges associated with in vivo phenotyping of heart valve function in mice. While recent reviews have provided thorough discussions regarding the advantages and disadvantages to numerous imaging and invasive modalities used to assess valve function in rodents9,10,11, to date, we are not aware of a publication that provides a comprehensive, step-by-step protocol for phenotyping heart valve function in mice.
The purpose of this manuscript is to describe the methods and protocols to phenotype heart valve function in mice. All methods and procedures have been approved by the Mayo Clinic Institutional Animal Care and Use Committee. Key components of this protocol include the depth of anesthesia, the evaluation of cardiac function, and the evaluation of heart valve function. We hope this report will not only serve to guide investigators interested in pursuing research in the field of heart valve disease, but will also start a national and international dialogue related to protocol standardization to ensure data reproducibility and validity in this rapidly-growing field. Importantly, successful imaging using high-resolution ultrasound systems requires a working knowledge of the principles of sonography (and terminology commonly used in sonography), an understanding of the fundamental principles of cardiac physiology, and significant experience with sonography to allow for accurate and time-efficient assessment of cardiac function in rodents.

<table border="0" cellpadding="0" cellspacing="0" width="1906">
	<tbody>
		<tr height="34">
			<td height="34" style="height:34px;width:693px;">High resolution ultrasound machine</td>
			<td style="width:453px;">VisualSonics, Fujifilm</td>
			<td style="width:293px;">Vevo 2100&#160;</td>
			<td style="width:467px;"></td>
		</tr>
		<tr height="68">
			<td height="68" style="height:68px;width:693px;">Isoflurane diffuser (capable of delivering 1 % to 1.5 % isoflurane mixed with 1 L/min 100% O2</td>
			<td>VisualSonics, Fujifilm</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr height="68">
			<td height="68" style="height:68px;width:693px;">Transducers for small mice (550D) or larger mice (400)</td>
			<td>MicroScan, VisualSonics, Fujifilm</td>
			<td>MS 550D, MS 400</td>
			<td></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:693px;">Animal platform</td>
			<td>VisualSonics, Fujifilm</td>
			<td>11503</td>
			<td></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:693px;">Advanced physiological monitoring unit</td>
			<td>VisualSonics, Fujifilm</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:693px;">Isoflurane</td>
			<td>Terrell</td>
			<td>NDC 66794-019-10</td>
			<td></td>
		</tr>
		<tr height="74">
			<td height="74" style="height:74px;width:693px;">Nose cone and tubing connected to isoflurane diffuser and 100% O2</td>
			<td>Custom Engineered in-house</td>
			<td>--</td>
			<td></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:693px;">Hair razor</td>
			<td>Andis Super AGR+ vet pack clipper</td>
			<td>AD65340</td>
			<td></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:693px;">Ultrasound gel</td>
			<td>Parker Laboratories</td>
			<td>REF 01-08</td>
			<td></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:693px;">Electrode gel&#160;</td>
			<td>Parker Laboratories</td>
			<td>REF 15-25</td>
			<td></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:693px;">Adhesive tapes</td>
			<td>Fisher Laboratories</td>
			<td>1590120B</td>
			<td></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:693px;">Paper towels</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

echocardiographic approaches and protocols for comprehensive phenotypic characterization of valvular heart disease in mice

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in rodents, with detailed descriptions of the appropriate methods for anesthesia, the echocardiographic windows used, the imaging planes and probe orientations for image acquisition, the methods for data analysis, and the limitations of emerging technologies for the evaluation of cardiac and valvular function. Importantly, we also highlight several future areas of research in cardiac and heart valve imaging that may be leveraged to gain insights into the pathogenesis of valve disease in preclinical animal models. We propose that using a systematic approach to evaluating cardiac and heart valve function in mice can result in more robust and reproducible data, as well as facilitate the discovery of previously underappreciated phenotypes in genetically-altered and/or physiologically-stressed mice.

Examples of images that are routinely obtained from animal cardiac ultrasound imaging are included in this manuscript. An illustration of transducer placement on the animal&#39;s chest is provided to give the reader a clear understanding of where the transducer is positioned to obtain the images as described. A photograph of the ultrasound laboratory set-up is also included to emphasize the importance of the proper equipment, particularly the ultrasound transducer to be used and the metho...

Watch this Scientific Journal Video about Echocardiographic Approaches and Protocols for Comprehensive Phenotypic Characterization of Valvular Heart Disease in Mice at JoVE.com

Echocardiographic Approaches and Protocols for Comprehensive Phenotypic Characterization of Valvular Heart Disease in Mice

This protocol provides a detailed description of the echocardiographic approach for comprehensive phenotyping of heart and heart valve function in mice.

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in ...

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