Gli autori riconoscono Dipartimento di Biotecnologie, Governo dell&#39;India per il sostegno finanziario di questo progetto. Ajith Kumar GS è stato sostenuto con borsa di ricerca senior Consiglio di ricerca scientifica e industriale, Governo dell&#39;India e Binil Raj con assegno di ricerca senior Consiglio indiano di ricerca medica, Governo dell&#39;India.

Gli esperimenti sugli animali sono stati eseguiti dopo aver ottenuto l&#39;approvazione del Comitato Etico Animal Istituzionale. Ratti Wistar sono stati alloggiati in un buio 12 ore al ciclo di luce, temperatura costante (24 ± 2 ° C), con cibo e acqua ad libitum (secondo le linee guida CPCSEA). 1) Assistenza pre-operatoria e anestesia <ol><li> Tenere rat (circa 200 g di peso corporeo), sotto antibiotico ombrello 24 ore prima dell&#39;intervento chirurgico con la somministrazione di amoxicillina per via orale (dose: 500 mg / L di acqua). </li><li> Sterilizzare tutti gli strumenti chirurgici (come forbici, pinze, clip applicatore, aghi da sutura, e porta-aghi) in autoclave a 121 ° C per 15 min. </li><li> Utilizzare una piastra elettrica per mantenere la temperatura corporea degli animali intorno ai 37 ° C per evitare una rapida diminuzione della frequenza cardiaca. </li><li> Fare attenzione ad evitare la disidratazione dell&#39;animale, prima e durante l&#39;intervento chirurgico. </li><li> Anestetizzare ratto in una camera di induzione con 3% isoflurano miscelato con0,5-1,0 L / min 100% di ossigeno; mantenere l&#39;anestesia con il 1,5% isoflurano. </li><li> Controllare il riflesso pedale per confermare l&#39;anestesia successo. </li></ol> 2) Preparazione del sito chirurgico <ol><li> Mantenere il topo sopra un cuscinetto riscaldante temperatura controllata in posizione supina. </li><li> Posizionare un elastico sopra denti anteriori del ratto di mantenere l&#39;animale in posizione mantenendo anestesia con un&#39;ogiva. </li><li> Rimuovere la pelliccia dal collo e lasciato regione toracica del ratto (preferibilmente con un rasoio elettrico). </li><li> Disinfettare sito chirurgico con soluzione di povidone-iodio e poi con il 70% di alcol etilico. </li><li> Utilizzare un telino sterile per esporre solo il sito chirurgico durante la procedura operativa. Nota: Come opzione aggiuntiva per la cura degli animali, 0,25% bupivicaine ID (2,5 mg / kg) può essere incorporato prima di incidere in ogni sito di incisione per l&#39;anestesia locale / analgesia. </li></ol> 3) tracheale intubazione in Rat <ol><li> Fare una piccola incisione sulla pelle parallela alla trachea con una lama chirurgica sterile e separare accuratamente il tessuto sottostante al fine di esporre la trachea. </li><li> Applicare una cravatta di seta 4-0 filo di sutura sotto la trachea e sollevare delicatamente la cravatta verso l&#39;alto. </li><li> Effettuare una incisione a metà strada tra due anelli cartilaginei e inserire la cannula tracheale nella trachea del ratto. </li><li> Collegare la cannula tracheale di un ventilatore roditore per mantenere una frequenza respiratoria di 50 respiri / min, volume corrente di 1.70 ml di tempo e l&#39;ispirazione di 0,60 sec (per ratto con 200 g di peso corporeo). </li></ol> 4) La costrizione dell&#39;aorta ascendente <ol><li> Dopo rilevando la posizione delle nervature con le dita, fare una incisione cutanea di circa 2 cm sulla parete toracica sinistra tra il secondo e terzo costole. </li><li> Separare lo strato muscolare intercostale dopo strato e fare un&#39;incisione lungo circa 1,5 cm tra il secondo e terzo costole. (Si deve essere rimessan per evitare lesioni ai polmoni rendendo incisione tra le costole) </li><li> Ritrarre le costole e individuare la porzione ascendente dell&#39;aorta. </li><li> Posizionare una piccola clip titanio dimensioni intorno l&#39;aorta ascendente con l&#39;aiuto di un applicatore quale costrizione dell&#39;aorta al 50-60% del diametro originale. </li><li> Seguendo la costrizione aortica, ravvicinare secondo e terzo costole con 3.0 prolene in un modello sutura interrotta. Allo stesso tempo, mettere in pausa il ventilatore per circa 2-4 secondi al fine di ri-gonfiare i polmoni. </li><li> Appose gli strati muscolari con 3.0 punti di sutura prolene e la pelle con 4,0 punti di sutura in seta in un modello di sutura interrotta. Sintetici suture non assorbibili possono essere utilizzati al posto di seta per sutura della pelle. </li><li> Rimuovere cannula tracheale dal ratto respirazione spontanea una volta viene ristabilita. </li><li> Chiudere l&#39;apertura tracheale con 3.0 punti di sutura prolene e lo strato di pelle con 4.0 punti di sutura in seta. </li><li> Lasciare che l&#39;animale di recuperare il tegli riscaldamento pad abbassando gradualmente la anestesia e ventilazione respirazione assistita. </li><li> In animali di controllo sham pari età, eseguire la tracheotomia e la toracotomia senza costrizione dell&#39;aorta ascendente. </li></ol> 5) assistenza post-operatoria <ol><li> Disinfettare area chirurgica con una soluzione di povidone-iodio. </li><li> Come analgesia post-operatoria, iniettare tramadol intra-peritoneale (10 mg / kg di peso corporeo / giorno) per 1 settimana. </li><li> Iniettare sterile normale soluzione fisiologica intra-peritoneale se i segni di disidratazione appaiono dopo l&#39;intervento chirurgico (circa 1 ml). </li><li> Somministrare amoxicillina per via orale, miscelato con acqua potabile, per sette giorni (dose: 500 mg / L di acqua). </li><li> Rimuovere eventuali punti di sutura in seta rimanenti dalla pelle dopo 10 giorni di intervento chirurgico sotto anestesia per inalazione. </li></ol> 6) Conferma della costrizione di successo di aorta ascendente <ol><li> Eseguire un trans-toracica bidimensionale Doppler-ecocardiografia per determinare l&#39;intensitàtà del sovraccarico di pressione prodotta dalla costrizione dell&#39;aorta ascendente. </li><li> Anestetizzare i ratti uno settimane post-chirurgia come descritto in precedenza (passo 1.5) </li><li> Posizionare il trasduttore di ultrasuoni nella posizione sternale supra registrare il gradiente di pressione attraverso la porzione ristretta dell&#39;aorta ascendente. Nota: Ratti con un gradiente di pressione di circa 60 mm di Hg sul sito costrizione aortica si svilupperà una grave ipertrofia cardiaca di circa 8-10 settimane dopo l&#39;intervento chirurgico. </li></ol>

<ol>
	<li>Patten, R. D., Hall-Porter, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Small+animal+models+of+heart+failure:+development+of+novel+therapies,+past+and+present.">Small animal models of heart failure: development of novel therapies, past and present.</a> Circ Heart Fail. 2, 138-144 (2009).</li><li>Weinberg, E. O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angiotensin-converting+enzyme+inhibition+prolongs+survival+and+modifies+the+transition+to+heart+failure+in+rats+with+pressure+overload+hypertrophy+due+to+ascending+aortic+stenosis.">Angiotensin-converting enzyme inhibition prolongs survival and modifies the transition to heart failure in rats with pressure overload hypertrophy due to ascending aortic stenosis.</a> Circulation. 90, 1410-1422 (1994).</li><li>Schunkert, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+rat+cardiac+angiotensin+converting+enzyme+activity+and+mRNA+expression+in+pressure+overload+left+ventricular+hypertrophy.+Effects+on+coronary+resistance,+contractility,+and+relaxation.">Increased rat cardiac angiotensin converting enzyme activity and mRNA expression in pressure overload left ventricular hypertrophy. Effects on coronary resistance, contractility, and relaxation.</a> J Clin Invest. 86, 1913-1920 (1990).</li><li>Hasenfuss, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+models+of+human+cardiovascular+disease,+heart+failure+and+hypertrophy.">Animal models of human cardiovascular disease, heart failure and hypertrophy.</a> Cardiovasc Res. 39, 60-76 (1998).</li><li>Litwin, S. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serial+echocardiographic-Doppler+assessment+of+left+ventricular+geometry+and+function+in+rats+with+pressure-overload+hypertrophy.+Chronic+angiotensin-converting+enzyme+inhibition+attenuates+the+transition+to+heart+failure.">Serial echocardiographic-Doppler assessment of left ventricular geometry and function in rats with pressure-overload hypertrophy. Chronic angiotensin-converting enzyme inhibition attenuates the transition to heart failure.</a> Circulation. 91, 2642-2654 (1995).</li><li>Miyamoto, M. I., 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=Adenoviral+gene+transfer+of+SERCA2a+improves+left-ventricular+function+in+aortic-banded+rats+in+transition+to+heart+failure.">Adenoviral gene transfer of SERCA2a improves left-ventricular function in aortic-banded rats in transition to heart failure.</a> Proc Natl Acad Sci U S A. 97, 793-798 (2000).</li><li>Kagaya, Y., Hajjar, R. J., Gwathmey, J. K., Barry, W. H., Lorell, B. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+angiotensin-converting+enzyme+inhibition+with+fosinopril+improves+depressed+responsiveness+to+Ca2++in+myocytes+from+aortic-banded+rats.">Long-term angiotensin-converting enzyme inhibition with fosinopril improves depressed responsiveness to Ca2+ in myocytes from aortic-banded rats.</a> Circulation. 94, 2915-2922 (1996).</li><li>Del Monte, F., Butler, K., Boecker, W., Gwathmey, J. K., Hajjar, 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=Novel+technique+of+aortic+banding+followed+by+gene+transfer+during+hypertrophy+and+heart+failure.">Novel technique of aortic banding followed by gene transfer during hypertrophy and heart failure.</a> Physiol Genomics. 9, 49-56 (2002).</li><li>Turcani, M., Rupp, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heart+failure+development+in+rats+with+ascending+aortic+constriction+and+angiotensin-converting+enzyme+inhibition.">Heart failure development in rats with ascending aortic constriction and angiotensin-converting enzyme inhibition.</a> Br J Pharmacol. 130, 1671-1677 (2000).</li><li>Kerem, 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=Lung+endothelial+dysfunction+in+congestive+heart+failure:+role+of+impaired+Ca2++signaling+and+cytoskeletal+reorganization.">Lung endothelial dysfunction in congestive heart failure: role of impaired Ca2+ signaling and cytoskeletal reorganization.</a> Circ Res. 106, 1103-1116 (2010).</li><li>Almeida, 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), (2010).</li></ol>

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Ci sono diversi modelli chirurgici per l&#39;induzione di sovraccarico di pressione e ipertrofia cardiaca e scompenso cardiaco. In piccoli animali, Lorell e colleghi hanno sviluppato il modello che abbiamo descritto qui ed hanno segnalato la comparsa di ipertrofia cardiaca compensata 8 settimane dopo banding aortico 5. Alterazioni cardiache gradualmente progredire a uno stato scompensata e poi portare a insufficienza cardiaca. Il vantaggio principale di questo modello è la graduale insorgenza di aumento dell...

Modelli piccoli animali sono gli strumenti più preferite per lo studio dei cambiamenti cronici nello sviluppo di ipertrofia cardiaca e la sua progressione a insufficienza cardiaca. Modelli di insufficienza cardiaca con metodi chirurgici sono stati originariamente sviluppati in ratti in quanto questi animali sono più adatti per interventi chirurgici al torace aperto, ecocardiografia e la valutazione dei parametri emodinamici. Essi forniscono inoltre adeguate campioni post mortem di tessuti, cellule e gli studi a livello molecolare 1. Costrizione dell&#39;aorta ascendente è uno dei modelli chirurgiche più comuni e di successo per la creazione di sovraccarico di pressione insufficienza cardiaca 2, 3. Questo modello è adatto per studiare gli eventi rimodellamento cellulare cellulari e sub e le proprietà contrattili del cuore durante la transizione da ipertrofia ad infarto 4. Un importante vantaggio di questo modello è la graduale insorgenza di sovraccarico di pressione sul cuore 5, &lt;/ Sup&gt; 6. Questo modello è clinicamente rilevante a causa della sua lenta ma costante progressione da ipertrofia cardiaca compensata a fase scompensata e infine alla fase insufficienza cardiaca. La durata per la progressione dell&#39;ipertrofia cardiaca per insufficienza cardiaca e cambiamenti fisiologici associati sono influenzati principalmente dal grado di stenosi prodotto 7. Ascendente costrizione aortica può essere eseguita in due modi, sia utilizzando suture o mediante l&#39;applicazione di clips metalliche 8, 9. Il principale vantaggio di utilizzare un clip metallico per costrizione aortica è che le procedure chirurgiche sono meno complicati. In questo metodo si deve individuare la sovra valvolare dell&#39;aorta ascendente e inserire la clip attorno l&#39;aorta per ottenere il livello desiderato di costrizione. Un divaricatore petto non è necessario in questa procedura. Banding aortico da sutura richiede manipolazioni più chirurgici per posizionare l&#39;ago calibro accanto alla aorta ascendente e sutura intorno aprodurre il livello desiderato di costrizione aortica. Quest&#39;ultima tecnica è più tempo rispetto all&#39;uso di clips metalliche per costrizione aortica. Il metodo descritto in questo video mostra la procedura chirurgica per crescente costrizione aortica in ratti che permette la creazione di pressione sovraccarico ventricolare sinistra ipertrofia modello.

<table border="0" cellpadding="0" cellspacing="0" width="742">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Wistar rats</td>
			<td style="width:149px;"></td>
			<td style="width:119px;"></td>
			<td style="width:220px;">Maintained at ARF, RGCB</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Inhalation anaesthesia systems&#160;</td>
			<td style="width:149px;">VetEquip</td>
			<td style="width:119px;">AB19276</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Rodent ventilator</td>
			<td style="width:149px;">CWE Inc</td>
			<td style="width:119px;">SAR- 830/AP&#160;</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Rat tracheal cannula</td>
			<td style="width:149px;">CWE Inc</td>
			<td style="width:119px;">13-21032</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Ultrasound system</td>
			<td style="width:149px;">Philips</td>
			<td style="width:119px;">HD7</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Ultrasound transducer</td>
			<td style="width:149px;">Philips</td>
			<td style="width:119px;">S 12</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Titanium clip (small)</td>
			<td style="width:149px;">Horizon</td>
			<td style="width:119px;">1204</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Clip applicator</td>
			<td style="width:149px;">Weck</td>
			<td style="width:119px;">137081</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Electric shaver</td>
			<td style="width:149px;">Vinverth</td>
			<td style="width:119px;">VBT0817</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">BP blade (size:11)</td>
			<td style="width:149px;">Surgeon</td>
			<td style="width:119px;">REF10111</td>
			<td>Preparation of surgical site</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Tramadol</td>
			<td style="width:149px;">Orchid health care</td>
			<td style="width:119px;">OCH043</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Amoxycillin Hydrochloride</td>
			<td style="width:149px;">Ranbaxy</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Isoflurane</td>
			<td style="width:149px;">Piramal health care</td>
			<td style="width:119px;">A23M10A</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Syringes</td>
			<td style="width:149px;">BD</td>
			<td style="width:119px;">2015-09</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">4-0 braided silk</td>
			<td style="width:149px;">Diamond</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">3-0 prolene</td>
			<td style="width:149px;">Johnson&#38;Johnson</td>
			<td style="width:119px;">NW018</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Surgical tape</td>
			<td style="width:149px;">Romsons</td>
			<td style="width:119px;">SH 6301</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Povidone iodine</td>
			<td style="width:149px;">Win Medicare</td>
			<td style="width:119px;"></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:255px;">Temp. controlled heating pad</td>
			<td style="width:149px;">Flamingo</td>
			<td style="width:119px;">HC1003</td>
			<td></td>
		</tr>
	</tbody>
</table>

ascending aortic constriction in rats for creation of pressure overload cardiac hypertrophy model

Crescente costrizione aortica è il modello chirurgica più comune e di successo per la creazione di sovraccarico di pressione indotta ipertrofia cardiaca e insufficienza cardiaca. Qui, descriviamo una procedura chirurgica dettagliata per la creazione sovraccarico di pressione e ipertrofia cardiaca in ratti mediante costrizione dell&#39;aorta ascendente con una piccola clip metallica. Dopo l&#39;anestesia, la trachea è intubato inserendo una cannula attraverso un&#39;incisione a metà strada tra due anelli di cartilagine trachea. Poi una incisione cutanea viene effettuata a livello del secondo spazio intercostale sulla parete toracica sinistra e strati muscolari vengono cancellati per identificare la parte ascendente dell&#39;aorta. L&#39;aorta ascendente viene costretto a 50-60% del suo diametro originale mediante applicazione di una piccola clip titanio dimensioni. A seguito di costrizione aortica, la seconda e terza costola vengono approssimate con punti di sutura prolene. La cannula tracheale viene rimossa la respirazione spontanea una volta è stata ristabilita. L&#39;animale è permesso di recuperare on per il rilievo di riscaldamento abbassando gradualmente anestesia. L&#39;intensità del sovraccarico di pressione creata dalla costrizione dell&#39;aorta ascendente è determinato registrando il gradiente di pressione utilizzando transtoracica bidimensionale Doppler-ecocardiografia. Nel complesso questo protocollo è utile per studiare gli eventi di rimodellamento e le proprietà contrattili del cuore durante la graduale insorgenza e la progressione da compensata ipertrofia cardiaca allo stadio di insufficienza cardiaca.

Nei nostri esperimenti siamo in grado di raggiungere oltre il 80% i tassi di sopravvivenza. L&#39;efficacia di costrizione aortica è stata confermata eseguendo ecocardiografia Doppler. Ratti (n = 6) con un gradiente di pressione di circa 60 mm di Hg nel sito ristretta aortica sono stati osservati per 8 settimane e sacrificato per analizzare lo sviluppo di ipertrofia cardiaca (Figura 1). Dopo 8 settimane di valutazione ecocardiografica post-chirurgia ha rivelato un significativo aumento dei parametri ve...

Watch this Scientific Journal Video about Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model at JoVE.com

Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model

Descriviamo una procedura graduale per la creazione di sovraccarico di pressione e ipertrofia ventricolare sinistra in ratti Wistar dalla costrizione dell&#39;aorta ascendente con una piccola clip metallica. Questo modello è ampiamente utilizzato per studiare i cambiamenti di rimodellamento durante l&#39;ipertrofia cardiaca e per identificare e valutare le strategie per la regressione di tali cambiamenti.

Crescente aortica Costrizione in ratti per la creazione di sovraccarico di pressione cardiaca Ipertrofia Modello

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart ...

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17.0K Views.  Rajiv Gandhi Centre for Biotechnology.  Descriviamo una procedura graduale per la creazione di sovraccarico di pressione e ipertrofia ventricolare sinistra in ratti Wistar dalla costrizione dell'aorta ascendente con una piccola clip metallica. Questo modello è ampiamente utilizzato per studiare i cambiamenti di rimodellamento durante l'ipertrofia cardiaca e per identificare e valutare le strategie per la regressione di tali cambiamenti. 

Video: Ascending Aortic Constriction in Rats for Creation of Pressure Overload Cardiac Hypertrophy Model

Ultrasound Based Assessment of Coronary Artery Flow and Coronary Flow Reserve Using the Pressure Overload Model in Mice

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow reserve (CFR) in humans. Reduced CFR is accompanied by marked intramyocardial and pericoronary fibrosis and is used as an indication of the severity of dysfunction. This study explores, step-by-step, the real-time changes measured in the coronary flow velocity, CFR and systolic to diastolic peak velocity (S/D) ratio in the setting of an aortic banding model in mice. By using a Doppler transthoracic imaging technique that yields reproducible and reliable data, the method assesses changes in flow in the septal coronary artery (SCA), for a period of over two weeks in mice, that previously either underwent aortic banding or thoracotomy. 
During imaging, hyperemia in all mice was induced by isoflurane, an anesthetic that increased coronary flow velocity when compared with resting flow. All images were acquired by a single imager. Two ratios, (1) CFR, the ratio between hyperemic and baseline flow velocities, and (2) systolic (S) to diastolic (D) flow were determined, using a proprietary software and by two independent observers. Importantly, the observed changes in coronary flow preceded LV dysfunction as evidenced by normal LV mass and fractional shortening (FS). 
The method was benchmarked against the current gold standard of coronary assessment, histopathology. The latter technique showed clear pathologic changes in the coronary artery in the form of peri-coronary fibrosis that correlated to the flow changes as assessed by echocardiography. 
The study underscores the value of using a non-invasive technique to monitor coronary circulation in mouse hearts. The method minimizes redundant use of research animals and demonstrates that advanced ultrasound-based indices, such as CFR and S/D ratios, can serve as viable diagnostic tools in a variety of investigational protocols including drug studies and the study of genetically modified strains.

Coronary flow reserve (CFR) is useful for assessment of myocardial oxygen demand and evaluation of cardiovascular risk. This study establishes a step-by-step transthoracic Doppler echocardiographic (TTDE) method for longitudinal monitoring of the changes in CFR, as measured from coronary artery in mice, under the experimental pressure overload of aortic banding.

Valutazione Ecografia base di coronaropatia Flow e flusso coronarico Reserve Utilizzando la pressione Sovraccarico modello nei topi

Transthoracic Doppler echocardiography (TTDE) is a clinically useful, noninvasive tool for studying coronary artery flow velocity and coronary flow ...

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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.

The goal of this protocol is to noninvasively assess cardiac structural and functional changes in a mouse model of heart disease created by transverse aortic constriction, using B- and M-mode echocardiography and color/pulse wave Doppler imaging.

Valutazione del Cardiac morfologiche e funzionali Variazioni modello murino di trasversale aortica costrizione da parte ecocardiografica 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 ...

A Model of Cardiac Remodeling Through Constriction of the Abdominal Aorta in Rats

Heart failure is one of the leading causes of death worldwide. It is a complex clinical syndromethat includes fatigue, dyspnea, exercise intolerance, and fluid retention. Changes in myocardial structure, electrical conduction, and energy metabolism develop with heart failure, leading to contractile dysfunction, increased risk of arrhythmias, and sudden death. Hypertensive heart disease is one of the key contributing factors of cardiac remodeling associated with heart failure. The most commonly-used animal model mimicking hypertensive heart disease is created via surgical interventions, such as by narrowing the aorta. Abdominal aortic constriction is a useful experimental technique to induce a pressure overload, which leads to heart failure. The surgery can be easily performed, without the need for chest opening or mechanical ventilation. Abdominal aortic constriction-induced cardiac pathology progresses gradually, making this model relevant to clinical hypertensive heart failure. Cardiac injury and remodeling can be observed 10 weeks after the surgery. The method described here provides a simple and effective approach to produce a hypertensive heart disease animal model that is suitable for studying disease mechanisms and for testing novel therapeutics.

A rat model of abdominal aortic constriction that induces cardiac hypertrophy and remodeling is described. An efficient, highly-reproducible, and minimally-invasive method is used to provide a simple yet useful platform for research in myocardial hypertrophy and dysfunction.

Un modello di rimodellamento cardiaco Attraverso Costrizione del Aorta addominale in Rats

Heart failure is one of the leading causes of death worldwide. It is a complex clinical syndromethat includes fatigue, dyspnea, exercise intolerance, and ...

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.

Minimamente invasiva trasversale aortica costrizione nei topi

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

Technique of Minimally Invasive Transverse Aortic Constriction in Mice for Induction of Left Ventricular Hypertrophy

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure overload-induced left ventricular hypertrophy (LVH) and its progression to heart failure. In the majority of the reported investigations, this procedure is performed with intubation and ventilation of the animal which renders it demanding and time-consuming and adds to the surgical burden to the animal. The aim of this protocol is to describe a simplified technique of minimally invasive TAC without intubation and ventilation of mice. Critical steps of the technique are emphasized in order to achieve low mortality and high efficiency in inducing LVH.
Male C57BL/6 mice (10-week-old, 25-30 g, n=60) were anesthetized with a single intraperitoneal injection of a mixture of ketamine and xylazine. In a spontaneously breathing animal following a 3-4 mm upper partial sternotomy, a segment of 6/0 silk suture threaded through the eye of a ligation aid was passed under the aortic arch and tied over a blunted 27-gauge needle. Sham-operated animals underwent the same surgical preparation but without aortic constriction. The efficacy of the procedure in inducing LVH is attested by a significant increase in the heart/body weight ratio. This ratio is obtained at days 3, 7, 14 and 28 after surgery (n = 6 - 10 in each group and each time point). Using our technique, LVH is observed in TAC compared to sham animals from day 7 through day 28. Operative and late (over 28 days) mortalities are both very low at 1.7%.
In conclusion, our cost-effective technique of minimally invasive TAC in mice carries very low operative and post-operative mortalities and is highly efficient in inducing LVH. It simplifies the operative procedure and reduces the strain put on the animal. It can be easily performed by following the critical steps described in this protocol.

The aim of this protocol is to describe step-by-step the technique of minimally invasive transverse aortic constriction (TAC) in mice. By elimination of intubation and ventilation which are mandatory for the commonly used standard procedure, minimally invasive TAC simplifies the operative procedure and reduces the strain put on the animal.

Tecnica di costrizione aortico trasversale mininvasiva in topi per induzione dell'ipertrofia ventricolare sinistra

Transverse aortic constriction (TAC) in mice is one of the most commonly used surgical techniques for experimental investigation of pressure ...

A Closed-chest Model to Induce Transverse Aortic Constriction in Mice

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to perform a partial thoracotomy to visualize the transverse aortic arch. However, the surgical trauma caused by the thoracotomy in open-chest models changes the respiratory physiology as the ribs are dissected and left unattached after chest closure. To prevent this, we established a minimally invasive, closed chest approach via lateral thoracotomy. Herein we approach the aortic arch via the 2nd intercostal space without entering the chest cavities, leaving the mouse with a less traumatic injury to recover from. We perform this operation using standard laboratory settings for open chest TAC procedures with equal survival rates. Apart from maintaining physiological breathing patterns due to the closed chest approach, the mice seem to benefit by showing rapid recovery, as the less invasive technique appears to facilitate a fast healing process and to reduce immune response after trauma.

Here, we present a protocol of Transverse Aortic constriction (TAC) via a lateral thoracotomy. This technique is a minimally invasive, closed chest surgical procedure aiming to simulate pressure overload and heart failure in mice utilizing standard TAC laboratory settings.

Un modello chiuso-cassa per indurre costrizione trasversale aortica in topi

Research on cardiac hypertrophy and heart failure is frequently based on pressure overload mouse models induced by TAC. The standard procedure is to ...

A Pulmonary Trunk Banding Model of Pressure Overload Induced Right Ventricular Hypertrophy and Failure

Right ventricular (RV) failure induced by sustained pressure overload is a major contributor to morbidity and mortality in several cardiopulmonary disorders. Reliable and reproducible animal models of RV failure are therefore warranted in order to investigate disease mechanisms and effects of potential therapeutic strategies. Banding of the pulmonary trunk is a common method to induce isolated RV hypertrophy but in general, previously described models have not succeeded in creating a stable model of RV hypertrophy and failure.
We present a rat model of pressure overload induced RV hypertrophy caused by pulmonary trunk banding (PTB) that enables different phenotypes of RV hypertrophy with and without RV failure. We use a modified ligating clip applier to compress a titanium clip around the pulmonary trunk to a pre-set inner diameter. We use different clip diameters to induce different stages of disease progression from mild RV hypertrophy to decompensated RV failure.
RV hypertrophy develops consistently in rats subjected to the PTB procedure and depending on the diameter of the applied banding clip, we can accurately reproduce different disease severities ranging from compensated hypertrophy to severe decompensated RV failure with extra-cardiac manifestations.
The presented PTB model is a valid and robust model of pressure overload induced RV hypertrophy and failure that has several advantages to other banding models including high reproducibility and the possibility of inducing severe and decompensated RV failure.

We present a surgical method to induce right ventricular hypertrophy and failure in rats.

Un tronco polmonare Banding modello di sovraccarico pressorio indotto da fallimento e ipertrofia ventricolare destra

Right ventricular (RV) failure induced by sustained pressure overload is a major contributor to morbidity and mortality in several cardiopulmonary ...

Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy

Based on twice transverse aortic constrictions (TACs) in mice, it is proved that myocardial hypertrophic preconditioning (MHP) could attenuate cardiomyocyte hypertrophy and slow down progression to heart failure. For novices, however, the MHP model is usually quite difficult to establish because of the technical obstacles in ventilator operation, opening the chest repeatedly, and bleeding caused by debanding. To facilitate this model, to increase the surgical success rate and to reduce the incidence of bleeding, we switched to absorbable sutures for the first TAC combing with a ventilator-free technique. Using a 2-week absorbable suture, we demonstrated that this procedure could cause significant myocardial hypertrophy in 2 weeks; and 4 weeks after surgery, myocardial hypertrophy was almost completely regressed to the baseline. Using this protocol, the operators could master the MHP model easily with a lower operation mortality.

This protocol presents an improved method to obtain transient myocardial hypertrophy with absorbable suture, simulating left ventricular hypertrophy decrease after removing pressure overload. It could be valuable for the studies on myocardial hypertrophic preconditioning.

Constrizione aortica trasversale operativa con sutura assorbibile per ottenere ipertrofia miocardica transitoria

Based on twice transverse aortic constrictions (TACs) in mice, it is proved that myocardial hypertrophic preconditioning (MHP) could attenuate ...

O-Ring Aortic Banding Versus Traditional Transverse Aortic Constriction for Modeling Pressure Overload-Induced Cardiac Hypertrophy

Aortic banding in mice is one of the most commonly used experimental models for cardiac pressure overload-induced cardiac hypertrophy and the induction of heart failure. The previously used technique is based on a threaded suture around the aortic arch tied over a blunted 27 G needle to create stenosis. This method depends on the surgeon manually tightening the thread and, thus, leads to high variance in the diameter size. A newly refined method described by Melleby et al. promises less variance and more reproducibility after surgery. The new technique, o-ring- aortic banding (ORAB), uses a non-slip rubber ring instead of a suture with a thread, resulting in reduced variation in pressure overload and reproducible phenotypes of cardiac hypertrophy. During surgery, the o-ring is placed between the brachiocephalic and left carotid arteries. Successful constriction is confirmed by echocardiography. After 1 day, correct placement of the ring results in an increased flow velocity in the transverse aorta over the o-ring-induced stenosis. After 2 weeks, impaired cardiac function is proven by decreased ejection fraction and increased wall thickness. Importantly, besides less variance in the diameter size, ORAB is associated with lower intra- and post-operative mortality rates compared with transverse aortic constriction (TAC). Thus, ORAB represents a superior method to the commonly used TAC surgery, resulting in more reproducible results and a possible reduction in the number of animals needed.

The present protocol describes a new technique of aortic banding in mice to induce pressure overload cardiac hypertrophy. For banding, a rubber ring with a fixed inner diameter is used. This new technique promises less variance and more reproducible data for future experiments.

Bendaggio aortico O-ring rispetto alla costrizione aortica trasversale tradizionale per modellare l'ipertrofia cardiaca indotta da sovraccarico pressorio

Aortic banding in mice is one of the most commonly used experimental models for cardiac pressure overload-induced cardiac hypertrophy and the induction of ...

Modified Heterotopic Abdominal Heart Transplantation and a Novel Aortic Regurgitation Model in Rats

Over the past 50 years, many researchers have reported heterotopic abdominal heart transplantation in mice and rats, with some variations in the surgical technique. Modifying the transplantation procedure to strengthen the myocardial protection could prolong the ischemia time while preserving the donor&#39;s cardiac function. This technique&#39;s key points are as follows: transecting the donor&#39;s abdominal aorta before harvesting to unload the donor&#39;s heart; perfusing the donor&#39;s coronary arteries with a cold cardioplegic solution; and topical cooling of the donor&#39;s heart during the anastomosis procedure. Consequently, since this procedure prolongs the acceptable ischemia time, beginners can easily perform it and achieve a high success rate.
Moreover, a new aortic regurgitation (AR) model was established in this work using a technique different from the existing one,&#160;which is created by inserting a catheter from the right carotid artery and puncturing the native aortic valve under continuous echocardiographic guidance. A heterotopic abdominal heart transplantation was performed using the novel AR model. In the protocol, after the donor&#39;s heart is harvested, a stiff guidewire is inserted into the donor&#39;s brachiocephalic artery and advanced toward the aortic root. The aortic valve is punctured by pushing the guidewire further even after the resistance is felt, thus inducing AR. It is easier to damage the aortic valve using this method than with the procedure described in the conventional AR model. Additionally, this novel AR model does not contribute to the recipient&#39;s circulation; therefore, this method is expected to produce a more severe AR model than the conventional procedure.

This study demonstrates a reproducible heterotopic abdominal heart transplantation technique in rats that beginners can learn and perform. Additionally, a novel aortic regurgitation model in rats is generated by performing heterotopic abdominal heart transplantation and damaging the donor's aortic valve using a guidewire after harvesting.

Trapianto di cuore addominale eterotopico modificato e un nuovo modello di rigurgito aortico nei ratti

Over the past 50 years, many researchers have reported heterotopic abdominal heart transplantation in mice and rats, with some variations in the surgical ...