Name: assessment of cardiac morphological and functional changes in mouse model of transverse aortic constriction by echocardiographic imaging
Uploaded: 2016-06-21T14:00:00.000+00:00
Duration: 9 min 5 s
Description: Watch this Scientific Journal Video about Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging at JoVE.com

The authors have nothing to disclose.

Das Protokoll folgt den Richtlinien der Institutional Animal Care und Use Committee der University of Washington. 1. Chirurgische Verfahren und Vorbereitung für die Imaging <ol><li> Gegenstand C57BL / 6 - Mäusen zu TAC oder Scheinoperation , wie zuvor beschrieben 10. </li><li> Eine Woche nach der TAC oder Scheinoperation, betäuben die Maus in die Induktionskammer mit 2% Isofluran gemischt mit 1 l / min O 2. Bestätigen Sie die richtige anesthetization durch Teilnahmslosigkeit bis Fuß oder Schwanz einklemmen. Verwenden Veterinär Salbe auf die Augen Trockenheit während der Narkose zu verhindern. Entfernen Sie die Brusthaare durch Enthaarungscreme Anwendung. Desinfizieren Sie die Haut von Mäusen mit 70% Ethanol. </li><li> Sichern Sie die Maus auf ein Tier-Handling-Plattform in der Rückenlage. Um einen konstanten Niveau der Narkose erhalten, verwenden Sie eine nosecone 0,5 zu liefern - 1% Isofluran mit 1 l / min O 2 gemischt. </li><li> Bewerben Elektroden-Gel auf die Pfoten der Maus und klebt sie an die Elektroden-Pad. </li><li> Legen Sie eine rektale Sonde Körpertemperatur zu überwachen. Aufrechterhaltung der Körpertemperatur bei 37 ° C über ein Heizkissen oder eine Lampe. </li><li> Tragen Sie eine Schicht vorgewärmten Ultraschall-Gel auf die Maus Brust, vor allem der Bereich des Herzens liegt. Hinweis: Entfernen Sie Ultraschall-Gel und trocknen Sie die Maus mit steriler Gaze nach dem Bildgebungsverfahren. </li></ol> 2. Geben Sie im Aortenbogen Ansicht, Verwenden B-Mode und Doppler-Imaging Quer Aortakonstriktion zur Bewertung <ol><li> Verwenden Sie die B-Modus-Einstellung, um den Aortenbogen Ansicht zu erhalten, um die Aorta, Hauptarterienäste und die Verengung Ort zu visualisieren. <ol><li> Kippen Sie die linke Seite der Plattform so weit wie möglich mit der Maus in die linke Dekubitus Position zu drehen. Halten Sie den Ultraschallwandler durch Ständer in vertikaler Position und legen Sie es auf der Brust auf der rechten Parasternallinie, mit der Kerbe zeigt in Richtung Kinn der Maus. Hinweis: Verwenden Sie die Maus nicht Thorax komprimieren, wenn die TRANSD SenkungÜçer; minimale Menge an Druck erforderlich. </li><li> Kippen Sie den Wandler auf der Ebene der Skapula und drehen leicht nach rechts, bis Aortenbogen in Sicht kommt. Beachten Sie die Quer Aortakonstriktion Stelle, die zwischen der Verzweigung der Truncus (IA) und linken Arteria carotis communis (LCCA) (Abbildung 1) befindet. Hinweis: Keine Verengung in Sham-Maus erkannt wird. </li></ol></li><li> Auf den &quot;Farb-Doppler&quot; -Taste auf der Arbeitsstation zu Farb-Doppler-Modus zu wechseln Direktionalität und die Geschwindigkeit des Blutflusses über der Verengungsstelle zu überwachen. Erwerben und Speichern von Bildern von den &quot;cine speichern&quot; klicken. </li><li> Klicken Sie auf die &quot;PW-Doppler&quot; Taste zum Wechseln zwischen Welle Doppler-Modus zu pulsieren, und Platz Probenvolumen (die gestrichelte Cursor-Box) unmittelbar distal der Engstelle Stelle für den stenotischen Strahl mit der höchsten Geschwindigkeit zu suchen, klicken Sie auf die &quot;PW-Doppler&quot; Taste zu erhalten, Wellenformen von Aorten-flow und messen Spitzengeschwindigkeit (Abbildung 2). </li><li> Berechnen Druckgradienten über die Website Engstelle unter Verwendung der modifizierten Bernoulli-Gleichung: Druckgefälle = 4 x V max 2. Nur gehören Mäuse mit einem Druckgradienten von 40 bis 80 mmHg für eine weitere Analyse reichen. </li></ol> 3. Im Parasternal langen Achse, den Einsatz B-Modus und M-Modus Bildgebung zur Beurteilung Cardiac Dimensions und Kontraktilität <ol><li> Mit der Maus auf die Plattform in der Rückenlage liegen, halten Sie die Wandler in vertikaler Art und Weise mit der Kerbe zeigt auf den Kopf der Maus. Senken Sie den Wandler auf dem Thorax parallel zur linken Parasternallinie und drehen 30 ° gegen den Uhrzeigersinn. </li><li> Verwenden B-Modus-Bildgebung eine volle lange Achse &quot;sagittal&quot; Ansicht des Herzens zu erhalten. Stellen Sie den Winkel des Wandlers und Fokustiefe linken Ventrikels sichtbar zu machen, die intraventrikuläre septalen Wand und einen kleinen Teil der rechten Ventrikelwand. Save die Bilder für die spätere Messungen der Herzwanddicke und Kammer Dimension. Mit &quot;Herz-Paket&quot;, wählen Sie Parameter wie IVS oder LVAW, LVID und LVPW, und klicken Sie dann auf das Bild für jeden Parameter entsprechenden Linien zu zeichnen, um die Messungen zu erhalten. </li><li> Beobachten Herzwandbewegungsmuster und prüfen, ob mögliche Bewegungsstörungen, einschließlich Akinese, Hypokinesie und Asynchronität. Hinweis: Akinese und Hypokinesie bezeichnen vollständige und teilweise Verlust der Bewegung der Herzwand sind. Asynchrony bezeichnet unregelmäßig, unkoordinierte Herzwandbewegung. </li><li> Schalter zu M-Modus, place M-mode - Cursor senkrecht zu den LV Wänden auf Höhe der Papillarmuskel und erfassen Bilder für die spätere Messung des Herzabmessungen und fractional shortening (Abbildung 3). </li></ol> 4. Im Parasternal Kurzachsenansicht, den Einsatz B-Modus und M-Modus Imaging Herz Morphologie beurteilen und Funktion <ol><li> From die parasternal langen Achse, erhalten parasternal Kurzachsenansicht des Wandlers 90 ° im Uhrzeigersinn durch Drehen. Einstellen der Wandler eine horizontale Querschnitts &quot;quer&quot; Ansicht des Herzens, in B-Modus zu geben, wobei beide Papillarmuskeln deutlich sichtbar und auf der rechten Seite (der 2 und 4-Uhr-Position). </li><li> Wechseln Sie in den M-Modus und legen Sie die M-Mode-Achse in der mittleren Ebene des linken Ventrikels. Erwerben und Speichern von Bildern für die spätere Messungen der Herzwanddicke, Kammer Dimension und fraktionelle Verkürzung (Abbildung 4). Mit &quot;Herz-Paket&quot;, wählen Sie Parameter in SAX (kurze Achse) einschließlich IVS oder LVAW, LVID und LVPW, und klicken Sie auf das Bild für jeden Parameter entsprechenden Linien zu zeichnen, um die Messungen zu erhalten. Hinweis: Die Messungen hier erhalten eng mit denen in der parasternal langen Achse (Abbildung 5) korrelieren sollte. </li></ol> 5. Im Apikale Vierkammerblick, VerwendenDoppler-Bildgebung zur Beurteilung systolisch und diastolisch Funktion <ol><li> Erhalten, die apikalen Vierkammerblick beide linken und rechten Ventrikel mit den Vorhöfen am unteren Rand des Bildschirms sichtbar zu machen. Im B-Modus, von der kurzen Achse Ansicht, kippen Sie die linke obere Ecke der Plattform Winkel der Kopf der Maus nach unten und den Wandler in Richtung der rechten Schulter der Maus orientieren. Dies ist im Wesentlichen eine &quot;koronalen&quot; Ansicht des Herzens gegen die Spitze oben schauen zu erreichen. </li><li> Visualisieren Sie die Mitralklappe in B-Modus, und schalten Sie auf Farb-Doppler-Modus, indem die Probe Volumen (die gestrichelte Cursor-Box) an der Spitze der Mitralklappe. </li><li> Wechseln Sie in den PW-Doppler-Modus Strömungsmuster über die Mitralklappe zu beurteilen. Ausrichten der Doppler-Sonde Cursor parallel zur Richtung der Mitral Blutung. Verwenden einer Sondenwinkel von weniger als 20 ° zur Spitzengeschwindigkeit (6) bestimmen. </li><li> Speichern Sie die Bilder für die spätere Messungen. Verwenden Sie &quot;Herz-Paket&quot; und wählen Sie &quot;MV Flow. &quot;Jeden Parameter Klicken Sie auf und ziehen Linien entsprechen, um die Messungen zu erhalten Verfügbare Messungen umfassen:. Peak E Geschwindigkeit (früh mit aktiver ventrikuläre Entspannung Füllung), Peak A Geschwindigkeit (spät mit Vorhofkontraktion Füllung), Mitral isovolumetrischen Entspannung und Kontraktionszeiten (IVRT und IVCT jeweils) und Auswurfzeit (ET). </li><li> Berechnen myokardiale Performance-Index (MPI) von MPI = (IVCT + IVRT) / ET. </li></ol> 6. Post-Verfahrens Behandlung von Tier <ol><li> Geben Analgesie und / oder steriler Kochsalzlösung intraperitoneal chirurgische Tiere, wenn notwendig. </li><li> Lassen Sie das Tier auf einem Heizkissen in Bauchlage zu erholen. Verwenden Sie kein Tier unbeaufsichtigt lassen, bis es genügend Bewusstsein zu halten Brustlage wiedergewonnen hat. Nicht ein Tier zurück, die das Verfahren für die Gesellschaft von anderen Tieren unterzogen wurde, bis sie vollständig erholt. </li></ol>

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	<li>Rockman, H. 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=Segregation+of+atrial-specific+and+inducible+expression+of+an+atrial+natriuretic+factor+transgene+in+an+in+vivo+murine+model+of+cardiac+hypertrophy.">Segregation of atrial-specific and inducible expression of an atrial natriuretic factor transgene in an in vivo murine model of cardiac hypertrophy.</a> Proc Natl Acad Sci USA. 88 (18), 8277-8281 (1991).</li><li>Tanaka, 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=Transthoracic+echocardiography+in+models+of+cardiac+disease+in+the+mouse.">Transthoracic echocardiography in models of cardiac disease in the mouse.</a> Circulation. 94 (5), 1109-1117 (1996).</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 (2), 138-144 (2009).</li><li>Heineke, J., Molkentin, J. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regulation+of+cardiac+hypertrophy+by+intracellular+signalling+pathways.">Regulation of cardiac hypertrophy by intracellular signalling pathways.</a> Nat Rev Mol Cell Biol. 7 (8), 589-600 (2006).</li><li>Oka, 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=Cardiac-specific+deletion+of+Gata4+reveals+its+requirement+for+hypertrophy,+compensation,+and+myocyte+viability.">Cardiac-specific deletion of Gata4 reveals its requirement for hypertrophy, compensation, and myocyte viability.</a> Circ Res. 98 (6), 837-845 (2006).</li><li>Gardin, J. M., Siri, F. M., Kitsis, R. N., Edwards, J. G., Leinwand, L. 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+left+ventricular+mass+and+systolic+function+in+mice.">Echocardiographic assessment of left ventricular mass and systolic function in mice.</a> Circ Res. 76 (5), 907-914 (1995).</li><li>Respress, J. L., Wehrens, X. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transthoracic+echocardiography+in+mice.">Transthoracic echocardiography in mice.</a> J Vis Exp. (39), e1738 (2010).</li><li>Pistner, A., Belmonte, S., Coulthard, T., Blaxall, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Murine+echocardiography+and+ultrasound+imaging.">Murine echocardiography and ultrasound imaging.</a> J Vis Exp. (42), e2100 (2010).</li><li>Patten, R. D., Aronovitz, M. J., Bridgman, P., Pandian, N. G. <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+pulse+wave+and+color+flow+Doppler+echocardiography+in+mouse+models+of+human+disease.">Use of pulse wave and color flow Doppler echocardiography in mouse models of human disease.</a> J Am Soc Echocardiogr. 15 (7), 708-714 (2002).</li><li>deAlmeida, A. C., van Oort, R. J., Wehrens, X. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transverse+aortic+constriction+in+mice.">Transverse aortic constriction in mice.</a> J Vis Exp. (38), e1729 (2010).</li><li>Pacher, P., Nagayama, T., Mukhopadhyay, P., B&#225;tkai, S., Kass, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measurement+of+cardiac+function+using+pressure-volume+conductance+catheter+technique+in+mice+and+rats.">Measurement of cardiac function using pressure-volume conductance catheter technique in mice and rats.</a> Nat Protoc. 3 (9), 1422-1434 (2008).</li><li>Larsen, T. 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=The+isolated+working+mouse+heart:+methodological+considerations.">The isolated working mouse heart: methodological considerations.</a> Pflugers Arch. 437 (6), 979-985 (1999).</li><li>Roth, D. M., Swaney, J. S., Dalton, N. D., Gilpin, E. A., Ross, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+anesthesia+on+cardiac+function+during+echocardiography+in+mice.">Impact of anesthesia on cardiac function during echocardiography in mice.</a> Am J Physiol Heart Circ Physiol. 282 (6), H2134-H2140 (2002).</li><li>Pearlman, A. S., Stevenson, J. G., Baker, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Doppler+echocardiography:+applications,+limitations+and+future+directions.">Doppler echocardiography: applications, limitations and future directions.</a> Am J Cardiol. 46 (7), 1256-1262 (1980).</li><li>Bauer, 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=Echocardiographic+speckle-tracking+based+strain+imaging+for+rapid+cardiovascular+phenotyping+in+mice.">Echocardiographic speckle-tracking based strain imaging for rapid cardiovascular phenotyping in mice.</a> Circ Res. 108 (8), 908-916 (2011).</li></ol>

This work was supported in part by NIH/NHLBI grants R00HL0908076 and R01HL116507 (to Q.L.).

Echokardiographie wurde in großem Umfang verwendet , um die Herzfunktion in Nagetiermodellen von Herzerkrankungen 2,6 beurteilen. Im Vergleich zu invasiven oder Terminal - Methoden wie Druck-Volumen - Schleifenmessung 11 und ex vivo Arbeits Herz 12, Echokardiographie bietet eine leistungsfähige, nichtinvasive Werkzeug zur Beurteilung laufenden Herz strukturelle und funktionelle Veränderungen in lebenden Tieren. Zur Gewinnung zuverlässiger Daten ist es wichtig , die Körperte...

Mouse models of heart disease, such as TAC and myocardial infarction (MI), have been proven to be valuable to study disease mechanisms as well as to develop novel therapeutic strategies3. TAC initially induces compensatory hypertrophy, but prolonged pressure overload leads to cardiac dilatation and heart failure4. The tightness of the aortic constriction directly determines the degree of cardiac hypertrophy and its transition to heart failure. Noninvasive and reliable measurement of pressure gradient across the aortic constriction is essential for the success of these studies. Doppler imaging has been used to assess pressure gradient produced by TAC5, which is a noninvasive alternative for catheter-based pressure measurement.
Echocardiography has been widely used to noninvasively measure cardiac morphology as well as systolic and diastolic function in mice6-8. Two-dimensional B-mode imaging is used to detect abnormal movements or structural changes of the heart. One-dimensional M-mode imaging is used for quantification of cardiac dimensions and contractility. Color and PW Doppler imaging has recently been used on rodent ultrasound, which has broad applications for echocardiography, including measurement of flow directionality and velocity, as well as systolic and diastolic performance9. 
Longitudinal real-time monitoring of cardiac function using echocardiography in B-mode, M-mode, color and PW Doppler mode provides comprehensive assessment of cardiac structure and function in mice under physiological and pathological conditions. Here we provide a detailed description of the use of echocardiographic imaging to monitor dynamic cardiac morphological and functional changes in mice following TAC or sham surgery.

<table><tbody><tr><td>Anesthesia equipment</td><td>Harvard Apparatus, 84 October Hill Road&lt;br/&gt; Holliston, MA</td><td>723015</td><td></td></tr><tr><td>Vevo 2100 Imaging System</td><td>VisualSonics Inc., 3080 Yonge Street Suite 6100, Box 66, Toronto, Ontario, Canada</td><td>Vevo 2100</td><td></td></tr><tr><td>Aquasonic ultrasound gel</td><td>Parker Laboratories, 286 Eldridge Rd, Fairfield, NJ&amp;nbsp;</td><td>03-50</td><td></td></tr><tr><td>Isoflurane</td><td>Piramal Healthcare, Inc, 3950 Schelden Circle&lt;br/&gt; Bethlehem, PA&amp;nbsp;</td><td>NDC 66794-017-25</td><td></td></tr><tr><td>F/air anesthesia gas filter unit</td><td>A.M. Bickford, Inc, 12318 Big Tree Rd, Wales Center, NY&amp;nbsp;</td><td>80120</td><td></td></tr></tbody></table>

assessment of cardiac morphological and functional changes in mouse model of transverse aortic constriction by echocardiographic imaging

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable noninvasive method is essential to assess real-time cardiac morphological and functional changes in animal models of heart disease. Transthoracic echocardiography represents an important tool for noninvasive assessment of cardiac structure and function2. Here we used a high-resolution ultrasound imaging system to monitor myocardial remodeling and heart failure progression over time in a mouse model of TAC. B-mode, M-mode, and Doppler imaging were used to precisely assess cardiac hypertrophy, ventricular dilatation, and functional deterioration in mice following TAC. Color and pulse wave (PW) Doppler imaging was used to noninvasively measure pressure gradient across the aortic constriction created by TAC and to assess transmitral blood flow in mice. Thus transthoracic echocardiographic imaging provides comprehensive noninvasive measurements of cardiac dimensions and function in mouse models of heart disease.

Figur 1 zeigt B-Modus - Bilder des Aortenbogens Ansicht Maus Herz unterworfen sham (1A) oder TAC Chirurgie (1B). Der Aortenbogen, Truncus, links Arteria carotis communis und linken Schlüsselbeinarterie gezeigt. Beachten Sie, dass Aortakonstriktion in TAC deutlich sichtbar ist, aber nicht Schein-Herz. Farb - Doppler - Bilder von Aorten - Ansicht sind in 2A gezeigt. Die Wellenformen des Aorten - Strömung über die Einsch...

Watch this Scientific Journal Video about Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging at JoVE.com

Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging

Das Ziel dieses Protokolls ist es, nicht-invasiven Herz strukturelle und funktionelle Veränderungen in einem Mausmodell der Herzkrankheit durch Quer Aortakonstriktion geschaffen beurteilen zu können, unter Verwendung von B- und M-Mode-Echokardiographie und Farbe / Puls-Doppler-Bildgebung.

Beurteilung der Herz Morphologische und funktionelle Veränderungen in Maus-Modell der Quer Aortakonstriktion durch Echokardiographie

Transverse aortic constriction (TAC) in mice has been used as a valuable model to study mechanisms of cardiac hypertrophy and heart failure1. A reliable ...

assessment-cardiac-morphological-functional-changes-mouse-model

Research

JoVE Journal

Medicine

18.1K Aufrufe.  University of Washington.  Das Ziel dieses Protokolls ist es, nicht-invasiven Herz strukturelle und funktionelle Veränderungen in einem Mausmodell der Herzkrankheit durch Quer Aortakonstriktion geschaffen beurteilen zu können, unter Verwendung von B- und M-Mode-Echokardiographie und Farbe / Puls-Doppler-Bildgebung. 

Serie: Assessment of Cardiac Morphological and Functional Changes in Mouse Model of Transverse Aortic Constriction by Echocardiographic Imaging

Transthoracic Echocardiography in Mice

In recent years, murine models have become the primary avenue for studying the molecular mechanisms of cardiac dysfunction resulting from changes in gene expression. Transgenic and gene targeting methods can be used to generate mice with altered cardiac size and function,1-3 and as a result, in vivo techniques are needed to evaluate their cardiac phenotype. Transthoracic echocardiography, pulse wave Doppler (PWD), and tissue Doppler imaging (TDI) can be used to provide dimensional measurements of the mouse heart and to quantify the degree of cardiac systolic and diastolic performance. Two-dimensional imaging is used to detect abnormal anatomy or movements of the left ventricle, whereas M-mode echo is used for quantification of cardiac dimensions and contractility.4,5 In addition, PWD is used to quantify localized velocity of turbulent flow,6 whereas TDI is used to measure the velocity of myocardial motion.7 Thus, transthoracic echocardiography offers a comprehensive method for the noninvasive evaluation of cardiac function in mice.

Transthoracic echocardiography offers a noninvasive method for the evaluation of cardiac function in mice. A combination of ultrasound and Doppler imaging modalities can be used to obtain dimensional measurements of the heart and intracardiac blood flow, which together provide an assessment of cardiac systolic and diastolic performance.

Transthorakale Echokardiographie in Mäuse

In recent years, murine models have become the primary avenue for studying the molecular mechanisms of cardiac dysfunction resulting from changes in gene ...

Forschung

Medizin

Murine Echocardiography and Ultrasound Imaging

Rodent models of cardiac pathophysiology represent a valuable research tool to investigate mechanism of disease as well as test new therapeutics.1 Echocardiography provides a powerful, non-invasive tool to serially assess cardiac morphometry and function in a living animal.2 However, using this technique on mice poses unique challenges owing to the small size and rapid heart rate of these animals.3 Until recently, few ultrasound systems were capable of performing quality echocardiography on mice, and those generally lacked the image resolution and frame rate necessary to obtain truly quantitative measurements. Newly released systems such as the VisualSonics Vevo2100 provide new tools for researchers to carefully and non-invasively investigate cardiac function in mice. This system generates high resolution images and provides analysis capabilities similar to those used with human patients. Although color Doppler has been available for over 30 years in humans, this valuable technology has only recently been possible in rodent ultrasound.4,5 Color Doppler has broad applications for echocardiography, including the ability to quickly assess flow directionality in vessels and through valves, and to rapidly identify valve regurgitation. Strain analysis is a critical advance that is utilized to quantitatively measure regional myocardial function.6 This technique has the potential to detect changes in pathology, or resolution of pathology, earlier than conventional techniques. Coupled with the addition of three-dimensional image reconstruction, volumetric assessment of whole-organs is possible, including visualization and assessment of cardiac and vascular structures. Murine-compatible contrast imaging can also allow for volumetric measurements and tissue perfusion assessment.

This video demonstrates use of a rail-mounted high-frequency ultrasound probe to perform echocardiography on an anesthetized mouse. The methods describe both conventional two-dimensional and M-mode measurements of cardiac function in addition to newer, more powerful tools such as color Doppler, strain analysis, as well as general and targeted contrast imaging.

Murine Echokardiographie und Ultraschall-Bildgebung

Rodent models of cardiac pathophysiology represent a valuable research tool to investigate mechanism of disease as well as test new therapeutics.1  ...

Ultrasonic Assessment of Myocardial Microstructure

Echocardiography is a widely accessible imaging modality that is commonly used to noninvasively characterize and quantify changes in cardiac structure and function. Ultrasonic assessments of cardiac tissue can include analyses of backscatter signal intensity within a given region of interest. Previously established techniques have relied predominantly on the integrated or mean value of backscatter signal intensities, which may be susceptible to variability from aliased data from low frame rates and time delays for algorithms based on cyclic variation. Herein, we describe an ultrasound-based imaging algorithm that extends from previous methods, can be applied to a single image frame&#160;and accounts for the full distribution of signal intensity values derived from a given myocardial sample. When applied to representative mouse and human imaging data, the algorithm distinguishes between subjects with and without exposure to chronic afterload resistance. The algorithm offers an enhanced surrogate measure of myocardial microstructure and can be performed using open-access image analysis software.

Echocardiography is commonly used to noninvasively characterize and quantify changes in cardiac structure and function. We describe an ultrasound-based imaging algorithm that offers an enhanced surrogate measure of myocardial microstructure and can be performed using open-access image analysis software.

Ultraschall-Bewertung der myokarddialen Mikrostruktur

Echocardiography is a widely accessible imaging modality that is commonly used to noninvasively characterize and quantify changes in cardiac structure and ...

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.

Beurteilung der rechtsventrikulären Struktur und Funktion in Maus-Modell der Lungenarterie Verengung durch transthorakale Echokardiographie

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

Transverse Aortic Constriction in Mice

Transverse aortic constriction (TAC) in the mouse is a commonly used experimental model for pressure overload-induced cardiac hypertrophy and heart failure.1 TAC initially leads to compensated hypertrophy of the heart, which often is associated with a temporary enhancement of cardiac contractility. Over time, however, the response to the chronic hemodynamic overload becomes maladaptive, resulting in cardiac dilatation and heart failure.2 The murine TAC model was first validated by Rockman et al.1, and has since been extensively used as a valuable tool to mimic human cardiovascular diseases and elucidate fundamental signaling processes involved in the cardiac hypertrophic response and heart failure development. When compared to other experimental models of heart failure, such as complete occlusion of the left anterior descending (LAD) coronary artery, TAC provides a more reproducible model of cardiac hypertrophy and a more gradual time course in the development of heart failure. Here, we describe a step-by-step procedure to perform surgical TAC in mice. To determine the level of pressure overload produced by the aortic ligation, a high frequency Doppler probe is used to measure the ratio between blood flow velocities in the right and left carotid arteries.3, 4 With surgical survival rates of 80-90%, transverse aortic banding is an effective technique of inducing left ventricular hypertrophy and heart failure in mice.

Transverse aortic constriction (TAC) in the mouse is a commonly used experimental model to study mechanisms underlying cardiac hypertrophy and heart failure development. Here, we describe procedures to constrict the aorta to create a reproducible degree of cardiac hypertrophy in mice.

Quer Aorten-Verengung in Mäuse

Transverse aortic constriction (TAC) in the mouse is a commonly used experimental model for pressure overload-induced cardiac hypertrophy and heart ...

Biologie

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.

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

Echokardiographische Ansätze und Protokolle für die umfassende phänotypischen Charakterisierung von Herzklappenerkrankungen bei Mäusen

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 ...

Minimally Invasive Transverse Aortic Constriction in Mice

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard open-chest transverse aortic constriction (TAC). Although transverse aortic constriction is a highly functional method for the induction of high pressure in the left ventricle, it is a more difficult and lengthy procedure due to its use of artificial ventilation with tracheal intubation. TAC is oftentimes also less survivable, as the newer method, MTAC, neither requires the cutting of the ribs and intercostal muscles nor tracheal intubation with a ventilation setup. In MTAC, as opposed to a thoracotomy to access to the chest cavity, the aortic arch is reached through a midline incision in the anterior neck. The thyroid is pulled back to reveal the sternal notch. The sternum is subsequently cut down to the second rib level, and the aortic arch is reached simply by separating the connective tissues and thymus. From there, a suture can be wrapped around the arch and tied with a spacer, and then the sternal cut and skin can be closed. MTAC is a much faster and less invasive way to induce left ventricular hypertension and enables the possibility for high-throughput studies. The success of the constriction can be verified using high-frequency trans-thoracic echocardiography, particularly color Doppler and pulsed-wave Doppler, to determine the flow velocities of the aortic arch and left and right carotid arteries, the dimension of the blood vessels, and the left ventricular function and morphology. A successful constriction will also trigger significant histopathological changes, such as cardiac muscle cell hypertrophy with interstitial and perivascular fibrosis. Here, the procedure of MTAC is described, demonstrating how the resulting flow changes in the carotid arteries can be examined with echocardiography, gross morphology, and histopathological changes in the heart.

Minimally invasive transverse aortic constriction (MTAC) conserves the essentials of regular transverse aortic constriction (TAC) while eliminating the use of a ventilator with tracheal intubation. It proves to be a highly desirable method for high-throughput studies on left ventricular overload, particularly in translational studies.

Minimal Invasive Quer Aortakonstriktion bei Mäusen

Minimally invasive transverse aortic constriction (MTAC) is a more desirable method for the constriction of the transverse aorta in mice than standard ...

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.

Echokardiographische und histologische Untersuchung der kardiale Morphologie in der Maus

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

Revealing Subtle Changes in Cardiac Function using Transthoracic Dobutamine Stress Echocardiography in Mice

Left ventricular (LV) dysfunction paves the final pathway for a multitude of cardiac disorders. With the non-invasive high-frequency transthoracic dobutamine stress echocardiography in humans, a reductionist investigation approach to unmask subtle changes in cardiac function has become possible. Here, we provide a protocol for using this technique in mice to facilitate expanded analysis of LV architecture and function in physiology and pathology enabling the observation of alterations in models of cardiac disease hidden in unstressed hearts. This investigation can be performed in one and the same animal and allows both, basal and pharmacologically stress-induced measurements. We outline detailed criteria for appropriate anesthesia, imaging-based LV analysis, consideration of intra- and interobserver variability, and obtaining positive inotrope response that can be attained in mice after intraperitoneal injection of dobutamine under near physiological conditions. To recapitulate the characteristics of human physiology and disease in small animal models, we highlight critical pitfalls in evaluation, e.g., a pronounced Bowditch effect in mice. To further meet translational objectives, we compare stress-induced effects in humans and mice. When used in translational studies, attention must be paid to physiological differences between mice and human. Experimental rigor dictates that some parameters assessed in patients can only be used with caution due to restrictions in spatial and temporal resolution in mouse models.

Left ventricular dysfunction constitutes the final common pathway for a host of cardiac disorders. We here provide a detailed protocol of transthoracic dobutamine stress echocardiography approach for comprehensive evaluation of the left ventricular function of mouse models of cardiac disease as well as cardiac phenotyping.

Left ventricular (LV) dysfunction paves the final pathway for a multitude of cardiac disorders. With the non-invasive high-frequency transthoracic ...

A Modified Technique for Transverse Aortic Constriction in Mice

Transverse aortic constriction (TAC) is a frequently used surgery in research regarding heart failure and cardiac hypertrophy based on the formation of pressure overload in mouse models. The main challenge of this procedure is to clearly visualize the transverse aortic arch and precisely band the target vessel. Classical approaches perform a partial thoracotomy to expose the transverse aortic arch. However, it is an open-chest model that causes a rather large surgical trauma and requires a ventilator during the surgery. To prevent unnecessary trauma and simplify the operating procedure, the aortic arch is approached via the proximal proportion of the sternum, reaching and binding the target vessel using a small self-made retractor that contains a snare. This procedure can be conducted without entering the pleura cavity and does not need a ventilator or microsurgical operation, which leaves the mice with physiological breathing patterns, simplifies the procedure, and significantly reduces operation time. Due to the less invasive approach and less operation time, mice can undergo fewer stress reactions and recover rapidly.

The present protocol describes a modified and simplified technique with a minimally invasive transverse aortic constriction (TAC) procedure using a self-made retractor. This procedure can be conducted without a ventilator or microscope and introduces pressure overload, eventually leading to cardiac hypertrophy or heart failure.

Eine modifizierte Technik zur transversalen Aortenverengung bei Mäusen

Transverse aortic constriction (TAC) is a frequently used surgery in research regarding heart failure and cardiac hypertrophy based on the formation of ...