Vorremmo ringraziare il Dott. Corey Reynolds e il Core mouse BCM Fenotipizzazione per il loro aiuto esperto con questo progetto e l&#39;accesso alle strutture tipo. XHTW è un WM Keck Foundation Scholar Illustri giovani nella ricerca medica, ed è anche supportato da NIH / NHLBI concede R01-R01-HL089598 e HL091947 e Distrofia Muscolare associazione concedere # 69238. Questo lavoro è supportato anche in parte dalla Fondazione Leducq Alleanza per CaMKII segnalazione di Cuore.

1. I topi preparazione per gli studi di imaging <ol><li> Prima gli studi di imaging, anestetizzare il mouse (2% isofluorano mescolato con 0,5 L / min 100% O 2) nella camera di induzione. Assicurati di filtro gas di scarico per la sicurezza dell&#39;operatore. Rimuovere l&#39;animale dalla camera di induzione e l&#39;utilizzo tosatrici per accorciare il pelo dalla scollatura a livello del torace a metà. Quindi rimuovere il corpo capelli rimanenti con la panna depilazione. Questa preparazione può essere effettuato un giorno prima degli studi di imaging per minimizzare potenziali risposte allo stress indesiderate nei topi. </li><li> Applicare duralube gel in entrambi gli occhi per evitare l&#39;essiccazione della sclera (evitare il contatto della cornea con l&#39;applicatore di gel). Posizionare il mouse anestetizzato in posizione supina in cima a una piastra elettrica con incorporato derivazioni al fine di mantenere la temperatura corporea. </li><li> Mettere il muso all&#39;interno di un cono collegati al sistema di anestesia per mantenere un livello stazionario sedazione durante tutta la procedura (1,0% al 1,5% isoflurano mescolato con 0,5 L / min 100% O 2). Eseguire un pizzico punta o la coda per confermare la sedazione. Se necessario, il livello di anestesia può essere regolato per ottenere una frequenza cardiaca di 450 ± 50 battiti al minuto (bpm). </li><li> Inserire delicatamente una sonda rettale (dopo lubrificante) di monitorare continuativamente e regolare la temperatura corporea tramite il pad di riscaldamento. E &#39;importante mantenere la temperatura corporea in un range ristretto (37,0 ° C ± 0,5 ° C), come anche moderati cambiamenti di temperatura e frequenza cardiaca influenzare la funzione cardiaca nei topi. </li><li> Applicare il gel elettrodi ai quattro zampe e incollate agli elettrodi ECG. </li></ol> 2. Funzione sistolica valutazione del Cuore <ol><li> Per iniziare questa procedura, applicare uno strato di gel per ultrasuoni preriscaldato al torace, in primo luogo l&#39;area sovrastante il cuore. Gel dovrebbe essere riscaldato a temperatura corporea approssimativa. Un volume di gel freddo può rapidamente aggiungere al tasso di perdita della temperatura corporea. Evitare bolle d&#39;aria nel gel, che possono interferire con l&#39;imaging a ultrasuoni. </li><li> Immobilizzare il mouse in una posizione leggermente verso l&#39;alto (a testa) con una leggera angolazione. Utilizzando un micromanipolatore, immobilizzare la sonda ecografica con un angolo di 90 ° tra la sonda e il cuore. </li><li> Per cominciare a fare le misurazioni ecocardiografiche asse corto, abbassare la sonda sul torace parasternale. Evitare di posizionare la sonda direttamente sopra lo sterno o sulla pelle, in modo da distorcere il segnale. </li><li> In primo luogo, eseguiremo bidimensionali (2D) immagini (&#39;B-mode&#39;) per ottenere una vista lungo l&#39;asse corto parasternale. Regolare l&#39;area di visualizzazione della sonda per ottenere un&#39;immagine completa a seconda delle dimensioni del cuore dell&#39;animale. </li><li> Un&#39;immagine corretta in questo orientamento includerà il ventricolo sinistro e una parte leggera della parete del ventricolo destro. La freccia (mostrato in video) indica i muscoli antero-laterale e postero-papillare, le pareti posteriore e anteriore del ventricolo sinistro, la parete del setto intraventricolare, e una parte leggera della parete del ventricolo destro. Durante queste misurazioni, prestare particolare attenzione ai potenziali alterazioni dei movimenti di parete (per esempio, ipocinesia, akinasia, asincronia) o aneurismi. </li><li> Quindi, useremo ecocardiografia M-mode, che fornisce un 1-dimensionali (1D) vista, per ottenere misurazioni multa di dimensioni e della contrattilità cardiaca. Memorizzare delle immagini acquisite per la successiva valutazione dei parametri della funzione sistolica ventricolare sinistra. </li></ol> 3. Valutazione della funzione diastolica del Cuore <ol><li> Mentre ancora la visualizzazione della parasternale asse corto, siamo in grado di eseguire Doppler tissutale (TDI) per misurare la velocità di movimento del miocardio. La regione di interesse è segnato per includere una parete posteriore del ventricolo sinistro per la valutazione degli assi radiali. La forma d&#39;onda ottenute avrà quattro punte per valutare la funzione diastolica: IVRT, E &#39;, A&#39;, e IVCT. S &#39;rappresenta la velocità sistolica. (Figura 3B) Questi parametri saranno descritti più avanti nella sezione rappresentante risultati. </li><li> Pulse-Doppler (PWD) può essere utilizzato per misurare la velocità del flusso sanguigno all&#39;interno di una piccola area ad una specifica profondità nel tessuto miocardico. Per l&#39;immagine della trans-mitralico modello di flusso, inclinare l&#39;animale all&#39;indietro in posizione di Trendelenburg. Inclinare la sonda verso l&#39;alto, in modo che la sonda è ortogonale con l&#39;apice del cuore. </li><li> Ora aumentare il livello isoflurano per abbassare la frequenza cardiaca a 300-350 bpm, che rallenterà il movimento della valvola mitrale. Per gli studi di confronto, è importante per mantenere la frequenza cardiaca simile tra gli animali. </li><li> Visualizzare i movimenti della valvola mitrale come punto di riferimento per misurare il flusso attraverso la valvola. Posizionare il volume del campione alla punta della valvola mitrale. </li><li> Misurare i modelli di flusso attraverso la valvola mitrale tramite PWD. Due onde sono tipicamente visto, uno che rappresenta il riempimento passivo del ventricolo (inizio [E] d&#39;onda), ecoerenti con il riempimento attivo con sistole atriale (atriale [A] onda) uno. In un cuore sano, la E-velocità dell&#39;onda è leggermente superiore a quella del Un&#39;onda (Figura 3C). </li><li> Una volta che tutte le misure sono, rimuovere il gel per elettrodi (strofinando delicatamente con garze standard) e vincoli dall&#39;animale. Permettere all&#39;animale sfrenato di recuperare in cima alla riscaldata ECG pad in posizione verticale e spegnere l&#39;anestesia. Quando il mouse si risveglia, tornare alla sua gabbia. </li></ol> 4. Rappresentante Risultati ecocardiografia transtoracica Non invasiva studi ecocardiografici possono essere utilizzati per valutare la morfologia e la funzione ventricolare sinistra in modelli murini di patologie cardiache. 4,5 Questa tecnica è ampiamente utilizzata e fornisce un&#39;alternativa alle procedure terminale per valutare la funzione LV, come intracardiaca pressione-volume measurements.8 o l&#39;ex modello cuore vivo di lavoro. 9 Valutazione delle dimensioni della camera da LV transtoracica ecocardiografia M-mode permette di individuare anomalie allargamento della camera bassa tensione o lo spessore della parete aumentato in vari modelli di malattie cardiache. 5 Così, ecocardiografia transtoracica, combinata con impulsi Doppler , costituisce un viale completo per la valutazione non invasiva della pressione sistolica e diastolica funzione cardiaca nei topi. <img src="/files/ftp_upload/1738/1738fig1.jpg" alt="Figura 1" /> Figura 1. Panoramica di Vevo 770 ad alta risoluzione In Vivo Micro-Imaging System ecocardiografia Doppler ed Imaging. (A) Usiamo il VisualSonics sistema ferroviario integrato con unità di monitoraggio fisiologico, ECG a bordo, e RMV 30MHz testa di scansione. (B) Il mouse è posizionato correttamente e moderazione nel consiglio di riscaldamento con elettrodi ECG (colore oro). I quattro arti sono registrate nel elettrodi ECG. (CD) fotografie che mostrano gli angoli corretto per pulse-Doppler utilizzato come strumento di funzione diastolica, come descritto nella sezione 4 del protocollo. L&#39;orientamento della sonda per misurazioni funzione sistolica si mostrano nel protocollo video. <img src="/files/ftp_upload/1738/1738fig2.jpg" alt="Figura 2" /> Figura 2. Rappresentante Immagini ecocardiografia 2D (B-mode). (A) para-sternale asse corto che mostra la parte anteriore del ventricolo sinistro (AW) e posteriore (PW) pareti, il muro del setto intraventricolare (SW), e la parete laterale (LW). Il diametro del lume ventricolare sinistra può essere misurato come il diametro interno del ventricolo sinistro (LVID). L&#39;asterisco indica il muscolo papillare postero-mediale. (B) apicale quattro camere con un area di visualizzazione sopra la valvola mitrale per la determinazione di E / A velocità di picco. MVAL, volantino della valvola mitrale anteriore; MVPL, volantino della valvola mitrale posteriore; RV, ventricolo destro; LV, ventricolo sinistro. <img src="/files/ftp_upload/1738/1738fig3.jpg" alt="Figura 3" /> Figura 3. Acquisizione e quantificazione dei dati e di Ecocardiografia Doppler. Questa figura contiene immagini rappresentative dei dati acquisiti corrispondenti alle immagini ecocardiografia 2D presentato nella Figura 2. (A) M-mode tracciare le linee che indicano telesistolico (ESD) e telediastolico diametri (EDD). LVAWD / S, spessore della parete ventricolare sinistra anteriore (diastole / sistole); LVPWD / S, a sinistra spessore della parete posteriore ventricolare (diastole / sistole). (B) tracciati rappresentante per Doppler tissutale della parete posteriore LV. IVRT, tempo isovolumica rilassamento; IVCT, tempo di contrazione isovolumica. E &#39;d&#39;onda corrisponde al moto dell&#39;anello mitrale durante il riempimento diastolico precoce del ventricolo sinistro, e la A&#39; onda proviene da sistole atriale durante la fine di riempimento del ventricolo sinistro. S &#39;rappresenta la velocità sistolica. (C) Pulse wave registrazione Doppler delle punte della valvola mitrale opuscolo fornisce mitrale modelli di velocità del flusso da cui presto velocità diastolica (E), la velocità diastolica in ritardo con la contrazione diastolica (A), e il rapporto E / A può essere derivata. Il IVRT è anche una variabile utile per caratterizzare la funzione diastolica e la pressione di riempimento. ET indica il tempo di eiezione.

<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>

E &#39;importante uniformare il livello di anestesia, 10 della temperatura corporea, e la frequenza cardiaca in una coorte di topi per facilitare il confronto tra i diversi gruppi o genotipi di topi usando ecocardiografia M-mode. Per la valutazione PWD di funzione diastolica, della frequenza cardiaca deve essere abbassato al fine di valutare le proprietà diastolica del cuore murino. Le funzioni vitali degli animali devono essere attentamente monitorati al fine di prevenire l&#39;insufficienza emodinamica e la morte. D&#39;altra parte, per misure di funzione sistolica mediante ecocardiografia M-modello, frequenza cardiaca inferiore a 400 battiti al minuto può causare telediastolico diametro per aumentare dovuti al riempimento aumentato del ventricolo sinistro.

* Il software richiesto è un software Vevo tra B-Modalità di applicazione, il polso onda applicazione Doppler, e cardiovascolare pacchetto di strumenti di analisi.

transthoracic echocardiography in mice

Negli ultimi anni, i modelli murini sono diventati la principale strada per lo studio dei meccanismi molecolari della disfunzione cardiaca derivanti da cambiamenti nell&#39;espressione genica. Transgeniche e metodi di gene targeting può essere utilizzato per generare topi con alterata funzione cardiaca e dimensioni,<sup&gt; 1-3</sup&gt; E, di conseguenza,<em&gt; In vivo</emTecniche&gt; sono necessari per valutare il loro fenotipo cardiaco. L&#39;ecocardiografia transtoracica, impulsi Doppler (PWD), e Doppler tissutale (TDI) può essere utilizzato per fornire misure dimensionali del cuore mouse e di quantificare il grado di cardiaca sistolica e diastolica prestazioni. L&#39;imaging bidimensionale viene utilizzato per rilevare l&#39;anatomia o movimenti anormali del ventricolo sinistro, mentre M-mode eco è utilizzato per la quantificazione delle dimensioni e della contrattilità cardiaca.<sup&gt; 4,5</sup&gt; Inoltre, PWD viene utilizzato per quantificare la velocità localizzata di flusso turbolento,<sup&gt; 6</sup&gt; Mentre TDI viene utilizzato per misurare la velocità del movimento del miocardio.<sup&gt; 7</sup&gt; Quindi, l&#39;ecocardiografia transtoracica offre un metodo completo per la valutazione non invasiva della funzione cardiaca nei topi.

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

Transthoracic Echocardiography in Mice

L&#39;ecocardiografia transtoracica offre un metodo non invasivo per la valutazione della funzione cardiaca nei topi. Una combinazione di ultrasuoni e Doppler modalità di imaging possono essere utilizzate per ottenere misure dimensionali del cuore e del flusso sanguigno intracardiaco, che insieme forniscono una valutazione delle cardiaca sistolica e diastolica prestazioni.

L&#39;ecocardiografia transtoracica in topi

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

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JoVE Journal

Medicine

61.5K Views.  Baylor College of Medicine (BCM). L'ecocardiografia transtoracica offre un metodo non invasivo per la valutazione della funzione cardiaca nei topi. Una combinazione di ultrasuoni e Doppler modalità di imaging possono essere utilizzate per ottenere misure dimensionali del cuore e del flusso sanguigno intracardiaco, che insieme forniscono una valutazione delle cardiaca sistolica e diastolica prestazioni.

Video: 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.

L&#39;ecocardiografia murini e imaging a ultrasuoni

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

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Medicina

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 ecocardiografia fetale

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 Misurazione della frequenza cardiaca in mouse da non invasiva ecocardiografia M-mode

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.

Valutazione del ventricolo destro Struttura e funzione in modello murino di polmonare Arteria Costrizione da ecocardiografia transtoracica

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.

Ultrasound-guided transtoracica intramiocardico iniezione nei topi

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

Carotid Artery Infusions for Pharmacokinetic and Pharmacodynamic Analysis of Taxanes in Mice

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study model. As the use of mouse models are often a vital step in preclinical drug discovery and drug development1-8, it is necessary to design a system to introduce drugs into mice in a uniform, reproducible manner. Ideally, the system should permit the collection of blood samples at regular intervals over a set time course. The ability to measure drug concentrations by mass-spectrometry, has allowed investigators to follow the changes in plasma drug levels over time in individual mice1, 9, 10. In this study, paclitaxel was introduced into transgenic mice as a continuous arterial infusion over three hours, while blood samples were simultaneously taken by retro-orbital bleeds at set time points. Carotid artery infusions are a potential alternative to jugular vein infusions, when factors such as mammary tumors or other obstructions make jugular infusions impractical. Using this technique, paclitaxel concentrations in plasma and tissue achieved similar levels as compared to jugular infusion. In this tutorial, we will demonstrate how to successfully catheterize the carotid artery by preparing an optimized catheter for the individual mouse model, then show how to insert and secure the catheter into the mouse carotid artery, thread the end of the catheter out through the back of the mouse&#8217;s neck, and hook the mouse to a pump to deliver a controlled rate of drug influx. Multiple low volume retro-orbital bleeds allow for analysis of plasma drug concentrations over time.

This method was developed with the goal of delivering a steady drug solution via the carotid artery, to assess the pharmacokinetics of novel drugs in mouse models.

Infusi carotide di farmacocinetica e di farmacodinamica Analisi dei taxani nei topi

When proposing the use of a drug, drug combination, or drug delivery into a novel system, one must assess the pharmacokinetics of the drug in the study ...

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.

Transtoracica Speckle monitoraggio ecocardiografia per la valutazione quantitativa del ventricolo sinistro del miocardio Deformazione

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

Murine Echocardiography of Left Atrium, Aorta, and Pulmonary Artery

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic pressure through echocardiography, as well as to obtain measurements of the Aorta and PA diameter in mice.
Mice older than 10 d of age can be analyzed using the present technique. The technique is composed of 3 main steps: set-up, image acquisition, and image analysis. The set-up step consists of getting the mouse anesthetized with 1% isoflurane, shaving it, and taping it in a supine position to a heated EKG board where the image acquisition will take place. The image acquisition step consists of learning to identify the cardiac structures and obtaining all the required images with its correspondent probe and axis in order to be able to calculate volumes and diameters. The image analysis step consists of measuring the previously acquired images with the aid of computer software.
Advantages of the proposed technique include a fast (15 min) procedure that would allow the researcher to evaluate interventions in a non-invasive, non-terminal approach and therefore follow the same mouse over time; each mouse can be used as its own control. This fact plus having the same operator perform all the acquisition and analysis for the entire experiment minimizes the limitation of operator-dependency. The present methodology is useful for mouse researchers in cardiovascular and pulmonary medicine.

The following protocol describes the methodology for the acquisition and analysis of echocardiographic images used to obtain the Left Atrial Volume (LAV), Aorta (Ao) diameter, and Pulmonary Artery (PA) diameter in mice. This technique is a non-invasive, non-terminal procedure that allows assessment of the cardiopulmonary function.

Murine ecocardiografia di Sinistra Atrium, Aorta, e l&#39;arteria polmonare

The present methodology teaches the investigator how to measure and use the LAV as a surrogate of chronic elevations in Left Ventricular diastolic ...

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.

Ecocardiografia 2D e 3D nell'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 ...

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.