Wir möchten Dr. Corey Reynolds und dem BCM-Maus Phänotypisierung Kern für ihre kompetente Hilfe bei diesem Projekt und Art Zugang zu den Einrichtungen zu danken. XHTW ist ein WM Keck Foundation Distinguished Young Scholar in der medizinischen Forschung, und wird auch von NIH / NHLBI gewährt R01-HL089598 und R01-HL091947 und Muscular Dystrophy Association Grant # 69238 unterstützt. Diese Arbeit ist zum Teil auch von der Stiftung Leducq Alliance for CaMKII Signaling in Herz unterstützt.

1. Vorbereitung Mice for Imaging Studies <ol><li> Vor der Bildgebung, betäuben die Maus (2% Isofluran mit 0,5 L / min 100% O 2) in der Induktion Kammer. Achten Sie darauf, Abgas für die Sicherheit des Bedieners zu filtern. Entfernen Sie das Tier aus der Induktion Kammer und die Nutzung Haarschneidemaschinen, um das Fell vom Halsausschnitt bis Mitte Brusthöhe rasieren. Dann entfernen Sie die restlichen Körperbehaarung mit Enthaarungscreme. Diese Vorbereitung kann durchgeführt werden, einen Tag vor der bildgebenden Verfahren, um potenzielle unerwünschte Stressreaktionen bei den Mäusen zu minimieren. </li><li> Bewerben duralube Gel, beide Augen zu verhindern Trocknung der Lederhaut (vermeiden Sie Kontakt mit der Hornhaut mit dem Gel-Applikator). Setzen Sie den narkotisierten Maus in Rückenlage auf einem Heizkissen mit integrierten EKG-Ableitungen, um die Körpertemperatur aufrecht zu erhalten. </li><li> Legen Sie die Schnauze in einem Nasenkonus mit dem Anästhesie-System zu einem steady-state Sedierung während des gesamten Verfahrens (1,0% bis 1,5% Isofluran mit 0,5 L / min 100% O 2 gemischt) aufrecht zu erhalten. Führen Sie eine Zehe oder Schwanz kneifen, um zu Sedierung zu bestätigen. Falls erforderlich, kann das Niveau der Anästhesie eingestellt, um eine Herzfrequenz von 450 ± 50 Schläge pro Minute (bpm) zu erhalten. </li><li> Schieben Sie eine rektale Sonde (nach Schmieröl) ständig zu überwachen und anzupassen Körpertemperatur über das Heizkissen. Es ist wichtig, um die Körpertemperatur in einem engen Bereich zu halten (37,0 ° C ± 0,5 ° C), als auch moderate Änderungen in der Temperatur und Herzfrequenz beeinflussen die Herzfunktion bei Mäusen. </li><li> Elektroden-Gel auf die vier Pfoten und klebt sie auf die EKG-Elektroden. </li></ol> 2. Auswertung systolische Funktion des Herzens <ol><li> Zu Beginn dieses Verfahrens, eine Schicht vorgeheizten Ultraschallgel auf die Brust, vor allem der Bereich über dem Herzen. Gel soll die Angleichung der Körpertemperatur erwärmt werden. Ein Volumen von kaltem Gel kann schnell auf die Rate der Körpertemperatur Verlust hinzuzufügen. Vermeiden Sie Luftblasen im Gel, das mit Ultraschall-Bildgebung stören können. </li><li> Immobilisierung der Maus in einen leichten Aufwärtstrend Position (Kopf) unter einem leichten Winkel. Mit einem Mikromanipulator, immobilisieren die Ultraschallsonde mit einem 90 ° Winkel zwischen der Sonde und des Herzens. </li><li> Zu Beginn macht kurzen Achse echokardiographischen Messungen niedriger die Sonde auf den Brustkorb parasternally. Vermeiden Sie es, die Sonde direkt über dem Brustbein oder auf die Haut, da dies das Signal verzerrt wird. </li><li> Zunächst führen wir zweidimensionale (2D)-Bildgebung (&quot;B-mode &#39;), um eine Ansicht entlang der parasternal kurzen Achse zu erhalten. Passen Sie die Anzeige der Sonde zu einem kompletten Bild je nach Größe des Tieres das Herz zu erhalten. </li><li> Ein richtiges Bild in dieser Ausrichtung wird auch die linke Herzkammer und ein geringer Teil der rechten Ventrikelwand. Der Pfeil (siehe Video) zeigt die anterolaterale und posteromedial Papillarmuskeln, die hinteren und vorderen Wand des LV, das intraventrikuläre Septum und ein geringer Teil der rechten Ventrikelwand. Bei diesen Messungen, besonderes Augenmerk auf potenzielle Wandbewegungsstörungen (zB Hypokinesie, akinasia, Asynchronie) oder Aneurysmen. </li><li> Als nächstes werden wir M-Mode-Echokardiographie, die eine 1-dimensional (1D) Ansicht bietet, zu feinen Messungen der kardialen Dimensionen und Kontraktilität zu erhalten. Shop erworbenen Bilder für die spätere Auswertung der Parameter der systolischen Funktion des linken Ventrikels. </li></ol> 3. Auswertung diastolische Funktion des Herzens <ol><li> Noch während der Anzeige der parasternal kurzen Achse, können wir durchführen Gewebe-Doppler-Bildgebung (TDI), um die Geschwindigkeit der myokardialen Bewegung zu messen. Die Region von Interesse ist markiert, um eine hintere Wand des linken Ventrikels für radiale Achse Auswertung einzubeziehen. Die Wellenform erhalten haben vier Peaks diastolischen Funktion auswerten: IVRT, E &#39;, A&#39;, und IVCT. S &#39;steht für systolische. (3B) Diese Parameter werden später in die repräsentative Ergebnisse beschrieben werden. </li><li> Pulse-Wave-Doppler (PWD) kann verwendet werden, um den Blutfluss Geschwindigkeit innerhalb einer kleinen Fläche zu messen in einer bestimmten Tiefe in das Herzmuskelgewebe werden. Um das Bild der trans-Mitral Strömungsmuster, kippen das Tier rückwärts in die Trendelenburg-Position. Kippen Sie die Sonde nach oben, so dass die Sonde senkrecht mit der Spitze des Herzens ist. </li><li> Jetzt erhöhen die Isofluran-Ebene, um die Herzfrequenz auf 300-350 bpm, die die Bewegung der Mitralklappe langsam senkt. Zum Vergleich: Studien, ist es wichtig, ähnliche Herzfrequenzen zwischen Tieren aufrecht zu erhalten. </li><li> Visualisieren Sie die Bewegungen der Mitralklappe als Bezugspunkt, um den Fluss durch das Ventil zu messen. Legen Sie die Probe Volumen an der Spitze der Mitralklappe. </li><li> Messen Sie die Strömungsmuster über der Mitralklappe unter Verwendung PWD. Zwei Wellen sind charakteristisch gesehen, eine Vertretung passive Füllung des Ventrikels (frühe [E] Welle), undeine konsistente mit aktiven Füllung mit Vorhofsystole (atrial [A]-Welle). In einem gesunden Herzen ist die E-Wellengeschwindigkeit etwas größer als die der A-Welle (Abbildung 3C). </li><li> Nachdem alle Messungen abgeschlossen sind, entfernen Sie die Elektroden-Gel (durch vorsichtiges Abwischen mit Standard-Gaze-Pads) und Beschränkungen aus dem Tierreich. Lassen Sie die hemmungslose Tier oben auf dem beheizten EKG-Pad in eine aufrechte Position zu erholen und Ausschalten der Anästhesie. Wenn die Maus weckt, senden Sie es an seinem Käfig. </li></ol> 4. Vertreter transthorakale Echokardiographie Ergebnisse Nichtinvasive echokardiographische Studien lässt sich die linksventrikuläre Morphologie und Funktion in Mausmodellen von Herzerkrankungen zu beurteilen. 4,5 Diese Technik ist weit verbreitet und stellt eine Alternative zum Terminal Verfahren zur LV-Funktion zu beurteilen, wie intrakardiale Druck-Volumen-Schleife measurements.8 oder die ex vivo arbeiten Herzmodell. 9 Beurteilung der LV Kammer Dimensionen transthorakale M-Mode-Echokardiographie ermöglicht zum Nachweis von abnormalen LV Kammer Erweiterung oder erhöhte Wandstärke in verschiedenen Modellen von Herzerkrankungen. 5 So, transthorakale Echokardiographie, mit PW-Doppler kombiniert , stellt eine umfassende Allee für die nicht-invasive Beurteilung der systolischen und diastolischen Herzfunktion bei Mäusen. <img src="/files/ftp_upload/1738/1738fig1.jpg" alt="Abbildung 1" /> Abbildung 1. Übersicht der Vevo 770 Hohe Auflösung In Vivo Micro-Imaging-System für die Echokardiographie und Doppler Imaging. (A) Wir verwenden die VisualSonics integrierten Schienensystem mit physiologischen Überwachungseinheit, EKG Bord, und RMV 30MHz Scan-Kopf. (B) Die Maus ist so positioniert und richtig Zurückhaltung auf die Heizung mit integrierten EKG-Elektroden (goldfarben). Die vier Gliedmaßen werden in die EKG-Elektroden geklebt. (CD) Fotografien richtigen Winkel für Puls-Doppler verwendet werden, um die diastolische Funktion Messungen, wie in Abschnitt 4 des Protokolls beschrieben erhalten. Probe Orientierung für den systolischen Funktion Messungen zeigen im Video-Protokoll. <img src="/files/ftp_upload/1738/1738fig2.jpg" alt="Abbildung 2" /> Abbildung 2. Vertreter 2D-Echokardiographie Bilder (B-Modus). (A) Para-sternalen kurzen Achse zeigt die linksventrikuläre anterior (AW) und posterioren (PW) Wände, die intraventrikuläre Septum (SW) und Seitenwand (LW). Der Durchmesser der linksventrikulären Lumen kann der linksventrikulären Innendurchmesser (LVID) gemessen werden. Der Stern zeigt die posteromedial Papillarmuskel. (B) Apical Vier-Kammer-Blick mit einem Sichtfenster über der Mitralklappe zur Bestimmung der E / A Spitzengeschwindigkeiten. MVAL, Mitralklappe anterioren Segels; MVPL, Mitralklappe posterioren Segels; RV, rechte Herzkammer; LV, linken Ventrikels. <img src="/files/ftp_upload/1738/1738fig3.jpg" alt="Abbildung 3" /> Abbildung 3. Erwerb und Quantifizierung der Echokardiographie und Doppler-Daten. Diese Zahl enthält repräsentative Bilder der erfassten Daten entspricht der 2D-Echokardiographie Bilder in Abbildung 2 dargestellt. (A) M-Mode-Tracing mit Linien, die end-systolischen (ESD) und enddiastolische Durchmesser (EDD). LVAWD / S, der linksventrikulären Vorderwand Dicke (Diastole / Systole); LVPWD / S, der linksventrikulären Hinterwand Dicke (Diastole / Systole). (B) Repräsentative Kurven für die Gewebe-Doppler-Bildgebung des LV Hinterwand. IVRT, isovolumetrischen Relaxationszeit; IVCT, isovolumetrischen Kontraktion Zeit. Die E-Welle entspricht der Bewegung des Mitralannulus während der frühen diastolischen Füllung des LV, und die A &#39;Welle stammt aus Vorhofsystole während der späten Füllung des LV. S &#39;darstellen systolische. (C) Pulse Doppler Aufzeichnung Mitralklappensegel Tipps bietet Mitral Einströmgeschwindigkeit Muster, aus denen Anfang der diastolische (E), spät diastolische mit diastolischer Kontraktion (A), und die E / A-Verhältnis abgeleitet werden kann. Die IVRT ist auch eine nützliche Variable, um die diastolische Funktion und Füllungsdrücke charakterisieren. ET zeigt Auswurf Zeit.

<ol>
	<li>Zhang, T. M. a. i. e. r., S, L., Dalton, N. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+deltaC+isoform+of+CaMKII+is+activated+in+cardiac+hypertrophy+and+induces+dilated+cardiomyopathy+and+heart+failure.">The deltaC isoform of CaMKII is activated in cardiac hypertrophy and induces dilated cardiomyopathy and heart failure.</a> Circ Res. 92 (8), 912-912 (2003).</li><li>Srivastava, D., Thomas, T., Lin, Q. <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+mesodermal+and+neural+crest+development+by+the+bHLH+transcription+factor,+dHAND.">Regulation of cardiac mesodermal and neural crest development by the bHLH transcription factor, dHAND.</a> Nat Genet. 16 (2), 154-154 (1997).</li><li>Sood, S., Chelu, M. G., van Oort, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intracellular+calcium+leak+due+to+FKBP12.6+deficiency+in+mice+facilitates+the+inducibility+of+atrial+fibrillation.">Intracellular calcium leak due to FKBP12.6 deficiency in mice facilitates the inducibility of atrial fibrillation.</a> Heart Rhythm. 5 (7), 1047-1047 (2008).</li><li>Gardin, J. M., Siri, F. M., Kitsis, R. N. <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), 907-907 (1995).</li><li>Tanaka, N., Dalton, N., Mao, L. <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), 1109-1109 (1996).</li><li>Patten, R. D., Aronovitz, M. J., Bridgman, P. <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), 708-708 (2002).</li><li>Garcia-Fernandez, M. A., Azevedo, J., Moreno, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Regional+Left+Ventricular+Diastolic+Dysfunction+Evaluated+by+Pulsed-Tissue+Doppler+Echocardiography.">Regional Left Ventricular Diastolic Dysfunction Evaluated by Pulsed-Tissue Doppler Echocardiography.</a> Echocardiography. 16 (5), 491-491 (1999).</li><li>Pacher, P., Nagayama, T., Mukhopadhyay, P. <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), 1422-1422 (2008).</li><li>Larsen, T. S., Belke, D. D., Sas, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Pflugers Arch. 437 (6), 979-979 (1999).</li><li>Roth, D. M., Swaney, J. S., Dalton, N. D. <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-H2134 (2002).</li></ol>

Es ist wichtig, das Niveau der Anästhesie, 10 Körpertemperatur und Herzfrequenz innerhalb einer Kohorte von Mäusen zu standardisieren, um den Vergleich zwischen verschiedenen Gruppen oder Genotypen von Mäusen zu erleichtern, wenn mit M-Mode-Echokardiographie. Für PWD Beurteilung der diastolischen Funktion, müssen Herzfrequenz abgesenkt, um den diastolischen Eigenschaften des murinen Herzen zu bewerten. Die Vitalfunktionen des Tieres muss genau beobachtet werden, um hämodynamische Scheitern und Tod zu verhindern. Auf der anderen Seite, kann für den systolischen Funktion Messungen mit M-Modell Echokardiographie, Herzfrequenz unter 400 Schlägen pro Minute führen enddiastolischen Durchmesser zu erhöhen aufgrund erhöhter Füllung des LV.

* Benötigte Software ist Vevo Software einschließlich B-Mode-Anwendung, Puls-Doppler-Anwendung und Herz-Kreislauf-Analyse-Tools-Paket.

transthoracic echocardiography in mice

In den letzten Jahren haben Mausmodellen werden die primäre Weg für die Untersuchung der molekularen Mechanismen der kardialen Dysfunktion, die sich aus Veränderungen in der Genexpression. Transgene und Gen-Targeting-Methoden können verwendet werden, um Mäuse mit veränderten kardialen Größe und Funktion zu erzeugen,<sup&gt; 1-3</sup&gt; Und als Ergebnis,<em&gt; In vivo</em&gt; Techniken sind erforderlich, um ihre Herz-Phänotyp zu bewerten. Transthorakale Echokardiographie, PW-Doppler (PWD) und Tissue Doppler Imaging (TDI) kann verwendet werden, um dreidimensionale Messungen der Maus Herz geben und den Grad der kardialen systolischen und diastolischen Leistung zu quantifizieren. Zwei-dimensionale Bildgebung wird verwendet, um abnorme Anatomie und Bewegungen des linken Ventrikels zu erkennen, während M-Mode-Echo für die Quantifizierung der kardialen Dimensionen und Kontraktilität verwendet wird.<sup&gt; 4,5</sup&gt; Darüber hinaus ist PWD verwendet, um lokale Geschwindigkeit der turbulenten Strömung zu quantifizieren,<sup&gt; 6</sup&gt; Während TDI wird verwendet, um die Geschwindigkeit der myokardialen Bewegung zu messen.<sup&gt; 7</sup&gt; So bietet transthorakale Echokardiographie eine umfassende Methode zur nicht-invasiven Beurteilung der Herzfunktion bei Mäusen.

Watch this Scientific Journal Video about Transthoracic Echocardiography in Mice at JoVE.com

Transthoracic Echocardiography in Mice

Transthorakale Echokardiographie bietet eine nichtinvasive Methode zur Beurteilung der Herzfunktion bei Mäusen. Eine Kombination aus Ultraschall und Doppler bildgebenden Verfahren kann verwendet werden, um dreidimensionale Messungen der Herz-und intrakardialen Blutflusses, die zusammen eine Beurteilung der kardialen systolischen und diastolischen Leistung zu erzielen.

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 ...

Research

JoVE Journal

Medicine

61.3K Aufrufe.  Baylor College of Medicine (BCM). Transthorakale Echokardiographie bietet eine nichtinvasive Methode zur Beurteilung der Herzfunktion bei Mäusen. Eine Kombination aus Ultraschall und Doppler bildgebenden Verfahren kann verwendet werden, um dreidimensionale Messungen der Herz-und intrakardialen Blutflusses, die zusammen eine Beurteilung der kardialen systolischen und diastolischen Leistung zu erzielen.

Serie: Transthoracic Echocardiography in Mice

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  ...

Forschung

Medizin

Murine Fetal Echocardiography

Transgenic mice displaying abnormalities in cardiac development and function represent a powerful tool for the understanding the molecular mechanisms underlying both normal cardiovascular function and the pathophysiological basis of human cardiovascular disease. Fetal and perinatal death is a common feature when studying genetic alterations affecting cardiac development 1-3. In order to study the role of genetic or pharmacologic alterations in the early development of cardiac function, ultrasound imaging of the live fetus has become an important tool for early recognition of abnormalities and longitudinal follow-up. Noninvasive ultrasound imaging is an ideal method for detecting and studying congenital malformations and the impact on cardiac function prior to death 4. It allows early recognition of abnormalities in the living fetus and the progression of disease can be followed in utero with longitudinal studies 5,6. Until recently, imaging of fetal mouse hearts frequently involved invasive methods. The fetus had to be sacrificed to perform magnetic resonance microscopy and electron microscopy or surgically delivered for transillumination microscopy. An application of high-frequency probes with conventional 2-D and pulsed-wave Doppler imaging has been shown to provide measurements of cardiac contraction and heart rates during embryonic development with databases of normal developmental changes now available 6-10. M-mode imaging further provides important functional data, although, the proper imaging planes are often difficult to obtain. High-frequency ultrasound imaging of the fetus has improved 2-D resolution and can provide excellent information on the early development of cardiac structures 11.

Fetal and perinatal death is a common feature when studying genetic alterations affecting cardiac development. High-frequency ultrasound imaging has improved 2-D resolution and can provide excellent information on early cardiac development and is an ideal method to detect the impact on cardiac structure and function prior to death.

Murine fetale Echokardiographie

Transgenic mice displaying abnormalities in  cardiac development and function represent a powerful tool for the understanding  the molecular mechanisms ...

In utero Measurement of Heart Rate in Mouse by Noninvasive M-mode Echocardiography

Congenital heart disease (CHD) is the most frequent noninfectious cause of death at birth. The incidence of CHD ranges from 4 to 50/1,000 births (Disease and injury regional estimates, World Health Organization, 2004). Surgeries that often compromise the quality of life are required to correct heart defects, reminding us of the importance of finding the causes of CHD. Mutant mouse models and live imaging technology have become essential tools to study the etiology of this disease. Although advanced methods allow live imaging of abnormal hearts in embryos, the physiological and hemodynamic states of the latter are often compromised due to surgical and/or lengthy procedures. Noninvasive ultrasound imaging, however, can be used without surgically exposing the embryos, thereby maintaining their physiology. Herein, we use simple M-mode ultrasound to assess heart rates of embryos at E18.5 in utero. The detection of abnormal heart rates is indeed a good indicator of dysfunction of the heart and thus constitutes a first step in the identification of developmental defects that may lead to heart failure.

In utero Measurement of Heart Rate in Mouse by Noninvasive M-mode Echocardiography

Ultra-high frequency ultrasound is a powerful live imaging tool to examine cardiac abnormalities in small animals. Its noninvasiveness allows maintaining the physiologic state of embryos. Herein, we show the use of M-mode ultrasound to measure the heart rates of embryos at E18.5 in utero.

In utero Messung der Herzfrequenz in Mouse von Nichtinvasive M-Mode-Echokardiographie

Congenital heart disease (CHD) is the most frequent noninfectious cause of death at birth. The incidence of CHD ranges from 4 to 50/1,000 births (Disease ...

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, ...

Ultrasound-guided Transthoracic Intramyocardial Injection in Mice

Murine models of cardiovascular disease are important for investigating pathophysiological mechanisms and exploring potential regenerative therapies. Experiments involving myocardial injection are currently performed by direct surgical access through a thoracotomy. While convenient when performed at the time of another experimental manipulation such as coronary artery ligation, the need for an invasive procedure for intramyocardial delivery limits potential experimental designs. With ever improving ultrasound resolution and advanced noninvasive imaging modalities, it is now feasible to routinely perform ultrasound-guided, percutaneous intramyocardial injection. This modality efficiently and reliably delivers agents to a targeted region of myocardium. Advantages of this technique include the avoidance of surgical morbidity, the facility to target regions of myocardium selectively under ultrasound guidance, and the opportunity to deliver injectate to the myocardium at multiple, predetermined time intervals. With practiced technique, complications from intramyocardial injection are rare, and mice quickly return to normal activity on recovery from anesthetic. Following the steps outlined in this protocol, the operator with basic echocardiography experience can quickly become competent in this versatile, minimally invasive technique.

Echocardiography-guided percutaneous intramyocardial injection represents an efficient, reliable, and targetable modality for the delivery of gene transfer agents or cells into the murine heart. Following the steps outlined in this protocol, the operator can quickly become competent in this versatile, minimally invasive technique.

Ultraschall-geführte Transthorakale intramyokardiale Injection in Mäuse

Murine models of cardiovascular disease are important for investigating pathophysiological mechanisms and exploring potential regenerative therapies. ...

Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation

The value of conventional echocardiography is limited by differences in inter-individual image interpretation and therefore largely dependent on the examiners&#39; expertise. Speckle tracking Echocardiography (STE) is a promising but technically challenging method that can be used to quantitatively assess regional and global systolic and diastolic myocardial performance. Myocardial strain and strain rate can be measured in all three dimensions&#160;&#8212; radial, circumferential, longitudinal &#8212; of myocardial deformation. Standard cross-sectional two-dimensional B-mode images are recorded and subsequently postprocessed by automated continuous frame-by-frame tracking and motion analysis of speckles within the myocardium. Images are recorded as digital loops and synchronized to a 3-lead EKG for timing purposes. Longitudinal deformation is assessed in the apical 4-, 3-, and 2-chamber views. Circumferential and radial deformation are measured in the parasternal short axis plane.
Optimal image quality and accurate tissue tracking are paramount for the correct determination of myocardial performance parameters. Utilizing transthoracic STE in a healthy volunteer, the present article is a detailed outline of the essential steps and potential pitfalls of quantitative echocardiographic myocardial deformation analysis.

Speckle tracking echocardiography is an emerging diagnostic imaging technique for the quantitative assessment of global and regional myocardial performance. Standard view echocardiographic motion images are recorded and deformation parameters are subsequently measured by automated continuous frame-by-frame tracking and motion analysis of speckles within the B-mode images of the myocardium.

Transthorakale Speckle-Tracking Echokardiographie für die quantitative Bewertung der linksventrikulären myokardialen Deformations

The value of conventional echocardiography is limited by differences in inter-individual image interpretation and therefore largely dependent on the ...

2D and 3D Echocardiography in the Axolotl (Ambystoma Mexicanum)

Cardiac malfunction as a result of ischemic heart disease is a major challenge, and regenerative therapies to the heart are in high demand. A few model species such as zebrafish and salamanders that are capable of intrinsic heart regeneration hold promise for future regenerative therapies for human patients. To evaluate the outcome of cardioregenerative experiments it is imperative that heart function can be monitored. The axolotl salamander (A. mexicanum) represents a well-established model species in regenerative biology attaining sizes that allows for evaluation of cardiac function. The purpose of this protocol is to establish methods to reproducibly measure cardiac function in the axolotl using echocardiography. The application of different anesthetics (benzocaine, MS-222, and propofol) is demonstrated, and the acquisition of two-dimensional (2D) echocardiographic data in both anesthetized and unanesthetized axolotls is described. 2D echocardiography of the three-dimensional (3D) heart can suffer from imprecision and subjectivity of measurements, and to alleviate this phenomenon a solid method, namely intra/inter-operator/observer analysis, to measure and minimize this bias is demonstrated. Finally, a method to acquire 3D echocardiographic data of the beating axolotl heart at a very high spatiotemporal resolution and with pronounced blood-to-tissue contrast is described. Overall, this protocol should provide the necessary methods to evaluate cardiac function and model anatomy, and flow dynamics in the axolotl using ultrasound imaging with applications in both regenerative biology and general physiological experiments.

2D and 3D Echocardiography in the Axolotl Ambystoma Mexicanum

Here we present echocardiography protocols for two-dimensional and three-dimensional image acquisition of the beating heart of the axolotl salamander (Ambystoma mexicanum), a model species in heart regeneration. These methods allow for longitudinal evaluation of cardiac function at a high spatiotemporal resolution.

2D und 3D Echokardiographie in der Axolotl (Z.B. geschieht)

Cardiac malfunction as a result of ischemic heart disease is a major challenge, and regenerative therapies to the heart are in high demand. A few model ...

Electromagnetic Navigation Transthoracic Nodule Localization for Minimally Invasive Thoracic Surgery

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or excision. Many of these nodules are identified and excised via minimally invasive thoracic surgery; however, subcentimeter and subsolid nodules are frequently difficult to identify intra-operatively. This can be mitigated by the use of electromagnetic transthoracic needle localization. This protocol delineates the step-by-step process of electromagnetic localization from the pre-operative period to the postoperative period and is an adaptation of the electromagnetically guided percutaneous biopsy previously described by Arias et al. Pre-operative steps include obtaining a same day CT followed by the generation of a three-dimensional virtual map of the lung. From this map, the target lesion(s) and an entry site are chosen. In the operating room, the virtual reconstruction of the lung is then calibrated with the patient and the electromagnetic navigation platform. The patient is then sedated, intubated, and placed in the lateral decubitus position. Using a sterile technique and visualization from multiple views, the needle is inserted into the chest wall at the prechosen skin entry site and driven down to the target lesion. Dye is then injected into the lesion and, then, continuously during needle withdrawal, creating a tract for visualization intra-operatively. This method has many potential benefits when compared to the CT-guided localization, including a decreased radiation exposure and decreased time between the dye injection and the surgery. Dye diffusion from the pathway occurs over time, thereby limiting intra-operative nodule identification. By decreasing the time to surgery, there is a decrease in wait time for the patient, and less time for dye diffusion to occur, resulting in an improvement in nodule localization. When compared to electromagnetic bronchoscopy, airway architecture is no longer a limitation as the target nodule is accessed via a transparenchymal approach. Details of this procedure are described in a step-by-step fashion.

Presented here is a protocol for lung nodule localization using dye marking via electromagnetically navigated transthoracic needle access. The technique described here can be accomplished in the peri-operative period to optimize nodule localization and to successful resection when performing minimally invasive thoracic surgery.

Elektromagnetische Navigation Transthorakale Knotenlokalisation für die minimalinvasive Thoraxchirurgie

The increased use of chest computed tomography (CT) has led to an increased detection of pulmonary nodules requiring diagnostic evaluation and/or ...

Transthoracic Echocardiographic Examination in the Rabbit Model

Large animal models such as the rabbit are valuable for translational preclinical research. Rabbits have a similar cardiac electrophysiology compared to that of humans and that of other large animal models such as dogs and pigs. However, the rabbit model has the additional advantage of lower maintenance costs compared to other large animal models. The longitudinal evaluation of cardiac function using echocardiography, when appropriately implemented, is a useful methodology for preclinical assessment of novel therapies for heart failure with reduced ejection fraction (e.g. cardiac regeneration). The correct use of this non-invasive tool requires the implementation of a standardized examination protocol following international guidelines. Here we describe, step by step, a detailed protocol supervised by veterinary cardiologists for performing echocardiography in the rabbit model, and demonstrate how to correctly obtain the different echocardiographic views and imaging planes, as well as the different imaging modes available in a clinical echocardiography system routinely used in human and veterinary patients.

Here we describe, step by step, a detailed protocol for performing echocardiography in the rabbit model. We show how to correctly obtain the different echocardiographic views and imaging planes, as well as the different imaging modes available in a clinical echocardiography system routinely used in human and veterinary patients.

Transthorakale Echokardiographische Untersuchung im Kaninchenmodell

Large animal models such as the rabbit are valuable for translational preclinical research. Rabbits have a similar cardiac electrophysiology compared to ...

Transthoracic Echocardiography to Assess Post-Resuscitation Left Ventricular Dysfunction After Acute Myocardial Infarction and Cardiac Arrest in Pigs

One of the main causes of out-of-hospital cardiac arrest is acute myocardial infarction (AMI). After successful resuscitation from cardiac arrest, approximately 70% of patients die before hospital discharge due to post-resuscitation myocardial and cerebral dysfunction. In experimental models, myocardial dysfunction after cardiac arrest, characterized by an impairment in both left ventricular (LV) systolic and diastolic function, has been described as reversible but very little data are available in cardiac arrest models associated with AMI in pigs. Transthoracic echocardiography is the first-line diagnostic test for the assessment of myocardial dysfunction, structural changes and/or AMI extension. In this pig model of ischemic cardiac arrest, echocardiography was done at baseline and 2-4 and 96 hours after resuscitation. In the acute phase, the examinations are done in anesthetized, mechanically ventilated pigs (weight 39.8 &#177; 0.6 kg) and ECG is recorded continuously. Mono- and bi-dimensional, Doppler and tissue Doppler recordings are acquired. Aortic and left atrium diameter, end-systolic and end-diastolic left ventricular wall thicknesses, end-diastolic and end-systolic diameters and shortening fraction (SF) are measured. Apical 2-, 3-, 4-, and 5-chamber views are acquired, LV volumes and ejection fraction are calculated. Segmental wall motion analysis is done to detect the localization and estimate the extent of myocardial infarction. Pulsed Wave Doppler echocardiography is used to record trans-mitral flow velocities from a 4-apical chamber view and trans-aortic flow from a 5-chamber view to calculate LV cardiac output (CO) and stroke volume (SV). Tissue Doppler Imaging (TDI) of LV lateral and septal mitral anulus is recorded (TDI septal and lateral s&#39;, e&#39;, a&#39; velocities). All the recordings and measurements are done according to the recommendations of the American and European Societies of Echocardiography Guidelines.

Transthoracic echocardiography is the first-line diagnostic test for post-resuscitation left ventricular dysfunction and structural changes in a pig model of cardiac arrest.

Transthorakale Echokardiographie zur Beurteilung der linksventrikulären Dysfunktion nach Reanimation nach akutem Myokardinfarkt und Herzstillstand bei Schweinen