Gostaríamos de agradecer ao Dr. Corey Reynolds eo BCM Núcleo Fenotipagem do mouse para a sua ajuda de peritos, com este projecto e acesso às instalações de tipo. XHTW é um WM Keck Foundation Scholar Distinguished Jovens em Pesquisa Médica, e também é suportado pelo NIH / NHLBI concede R01-R01-HL089598 e HL091947 e Muscular Dystrophy Association conceder # 69238. Este trabalho também é suportado, em parte, pela Leducq Fundação Aliança para Sinalização CaMKII no Coração.

1. Ratos se preparando para estudos de imagem <ol><li> Antes de os estudos de imagem, anestesiar o rato (isoflurano a 2% misturado com 0,5 L / min 100% O 2) na câmara de indução. Certifique-se de filtro de fumo para a segurança do operador. Remover o animal da câmara de indução e use cortar cabelo para raspar a pele do decote no peito ao nível médio. Em seguida, retire o cabelo com o creme restante do corpo depilação. Esta preparação pode ser realizada um dia antes de estudos de imagem para minimizar potenciais respostas ao estresse indesejado nos ratos. </li><li> Aplicar duralube gel para ambos os olhos para evitar a secagem da esclera (evitar contato com a córnea com o aplicador de gel). Posicione o mouse anestesiados em decúbito dorsal sobre uma almofada de aquecimento com embutidos ECG, a fim de manter a temperatura corporal. </li><li> Coloque o focinho dentro de um cone de nariz ligado ao sistema de anestesia para manter um nível de sedação steady-state durante todo o procedimento (1,0% para 1,5%, isoflurano misturado com 0,5 L / min 100% O 2). Realizar uma pitada toe ou cauda para confirmar sedação. Se necessário, o nível de anestesia pode ser ajustado para obter uma freqüência cardíaca alvo de 450 ± 50 batimentos por minuto (bpm). </li><li> Suavemente inserir uma sonda retal (após lubrificação) para monitorar continuamente e ajustar a temperatura do corpo através da almofada de aquecimento. É importante para manter a temperatura corporal dentro de uma faixa estreita (37,0 ° C ± 0,5 ° C), como até mesmo mudanças moderadas na temperatura e freqüência cardíaca afetam a função cardíaca em camundongos. </li><li> Aplique gel eletrodo aos quatro patas e gravá-los para os eletrodos de ECG. </li></ol> 2. Função Sistólica avaliação do Coração <ol><li> Para iniciar este procedimento, aplique uma camada de gel de ultra-som pré-aquecido até o peito, principalmente a área que cobre o coração. Gel deve ser aquecido à temperatura corporal aproximados. Um volume de gel frio pode rapidamente aumentar a taxa de perda de temperatura corporal. Evite bolhas de ar no gel, o que pode interferir com a imagem ultra-sônica. </li><li> Imobilizar o mouse em uma posição ligeiramente para cima (até a cabeça) com um pequeno ângulo. Usando um micromanipulador, imobilizar a sonda de ultra-som com um ângulo de 90 ° entre a sonda eo coração. </li><li> Para começar a fazer curto-eixo medidas ecocardiográficas, menor a sonda sobre o tórax parasternally. Evite colocar a sonda diretamente sobre o esterno ou sobre a pele, pois isso irá distorcer o sinal. </li><li> Primeiro, vamos realizar duas dimensões (2D) imagem (&quot;B-mode &#39;) para obter uma visão ao longo do eixo curto paraesternal. Ajustar a área de visualização da sonda para obter uma imagem completa, dependendo do tamanho do coração do animal. </li><li> Uma imagem adequada neste orientação irá incluir o ventrículo esquerdo e uma pequena parte da parede do ventrículo direito. A seta (mostrado no vídeo) indica os músculos ântero-lateral e póstero-papilar, as paredes anterior e posterior do VE, a parede septal intraventricular, e uma parcela pequena da parede do ventrículo direito. Durante essas medidas, preste especial atenção ao potencial de anormalidades na movimentação das paredes (por exemplo, hipocinesia, akinasia assincronia) ou aneurismas. </li><li> Em seguida, vamos usar no modo M, que fornece uma visão 1-dimensional (1D), para obter medidas multa de dimensões e contratilidade cardíaca. Armazenar as imagens adquiridas para posterior avaliação de parâmetros de função sistólica ventricular esquerda. </li></ol> 3. Avaliar a função diastólica do Coração <ol><li> Enquanto a visualização do eixo curto paraesternal, podemos realizar o Doppler tecidual (TDI) para medir a velocidade de movimentação do miocárdio. A região de interesse é marcado para incluir uma parede posterior do ventrículo esquerdo para avaliação do eixo radial. A forma de onda obtida terá quatro picos para avaliar a função diastólica: TRIV, E &#39;, A&#39;, e TCIV. S &#39;representa velocidade sistólica. (Figura 3B) Estes parâmetros serão descritos mais adiante na seção de resultados representativos. </li><li> Pulso de onda Doppler (PWD) pode ser usado para medir a velocidade do fluxo sanguíneo dentro de uma pequena área de uma determinada profundidade no tecido do miocárdio. Para a imagem do padrão de fluxo trans-mitral, incline o animal para trás na posição de Trendelenburg. Inclinação da sonda para cima, tais que a sonda é ortogonal com o ápice do coração. </li><li> Agora aumentar o nível de isoflurano para diminuir a freqüência cardíaca a 300-350 bpm, o que irá atrasar o movimento da válvula mitral. Para estudos comparativos, é importante para manter a freqüência cardíaca semelhante entre os animais. </li><li> Visualize os movimentos da válvula mitral como ponto de referência para medir o fluxo através da válvula. Coloque o volume da amostra na ponta da válvula mitral. </li><li> Medida os padrões de fluxo através da válvula mitral usando PWD. Duas ondas são caracteristicamente vistos, uma representando o enchimento passivo do ventrículo (precoce [E] wave), econsistente com o preenchimento ativa com a sístole atrial (onda [A] atrial). Em um coração saudável, a velocidade da onda E é ligeiramente maior do que a onda A (Figura 3C). </li><li> Uma vez que todas as medições são concluídos, remova o gel do eletrodo (suavemente limpar com compressas de gaze padrão) e as restrições do animal. Permitir que o animal desenfreada para recuperar em cima da almofada aquecida ECG em uma posição ereta e desligue a anestesia. Quando o mouse desperta, devolvê-lo à sua jaula. </li></ol> 4. Representante transtorácico Resultados Ecocardiografia Não-invasivo ecocardiografia pode ser usada para avaliar a morfologia e função ventricular esquerda em modelos murinos de doenças cardíacas. 4,5 Esta técnica é amplamente utilizada e fornece uma alternativa aos procedimentos de terminal para avaliar a função LV, tais como ciclo pressão-volume intracardíaco measurements.8 ou ex vivo modelo de coração de trabalho. 9 Avaliação de dimensões LV câmara por ecocardiografia transtorácica modo-M permite a detecção de aumento anormal da câmara do VE ou aumento da espessura da parede em vários modelos de doença cardíaca. 5 Assim, o ecocardiograma transtorácico, combinado com pulso de onda Doppler , constitui um caminho completo para a avaliação não-invasiva da função cardíaca sistólica e diastólica em camundongos. <img src="/files/ftp_upload/1738/1738fig1.jpg" alt="Figura 1" /> Figura 1. Visão geral do Vevo Resolução 770 Alta In Vivo Sistema de Micro-Imaging para Ecocardiografia e Doppler. (A) Usamos o sistema ferroviário VisualSonics integrada com unidade de monitoração fisiológica, placa EKG, e 30MHz RMV cabeça de leitura. (B) O mouse é posicionado corretamente e contenção na placa de aquecimento com eletrodos integrados ECG (cor ouro). Os quatro membros são gravadas na eletrodos de ECG. (CD) Fotografias mostrando ângulos adequados para pulso-Doppler de onda usado para obter medidas de função diastólica, como descrito no ponto 4 do protocolo. Sonda de orientação para as medições da função sistólica são mostrados no protocolo de vídeo. <img src="/files/ftp_upload/1738/1738fig2.jpg" alt="Figura 2" /> Figura 2. Representante 2D Imagens de Ecocardiografia (B-mode). (A) Para-esternal visão de curto eixo mostrando o anterior do ventrículo esquerdo (AW) e posterior (PW) paredes, a parede septal intraventricular (SW), e da parede lateral (PV). O diâmetro do lúmen do ventrículo esquerdo pode ser medida como o diâmetro do ventrículo esquerdo interna (DIVE). O asterisco indica o músculo papilar póstero-medial. (B) vista de quatro câmaras apical com uma área de visualização sobre a válvula mitral para a determinação de E / A velocidades de pico. MVAL, folheto anterior da valva mitral; MVPL, folheto posterior da válvula mitral; RV, ventrículo direito; LV, do ventrículo esquerdo. <img src="/files/ftp_upload/1738/1738fig3.jpg" alt="Figura 3" /> Figura 3. Aquisição e Quantificação de Dados Ecocardiografia e Doppler. Este número contém imagens representativas de dados adquiridos correspondentes às imagens 2D ecocardiografia apresentado na Figura 2. (A) M-mode traçado com linhas indicando sistólico final (ESD) e diastólica final diâmetros (EDD). LVAWD / S, do ventrículo esquerdo a espessura da parede anterior (diástole / sístole); PPVED / S, do ventrículo esquerdo a espessura da parede posterior (diástole / sístole). (B) traçados Representante para Doppler tecidual da parede posterior do VE. TRIV, o tempo de relaxamento isovolumétrico; TCIV, tempo de contração isovolumétrica. E a &#39;onda corresponde ao movimento do anel mitral durante enchimento diastólico inicial do LV, e os A&#39; onda origina-sístole atrial durante o final de enchimento do VE. S &#39;representam velocidade sistólica. (C) pulso de onda de gravação Doppler de dicas folheto da valva mitral fornece padrões de fluxo mitral velocidade a partir do qual a velocidade diastólica precoce (E), velocidade diastólica final com a contração diastólica (A), ea relação E / A pode ser obtida. O TRIV também é uma variável útil para caracterizar a função diastólica e pressões de enchimento. ET indica tempo de ejeção.

<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>

É importante padronizar o nível de anestesia, 10, temperatura corporal e freqüência cardíaca dentro de uma coorte de ratos para facilitar a comparação entre os grupos ou genótipos diferentes de camundongos ao usar modo M da ecocardiografia. PWD para avaliação da função diastólica, freqüência cardíaca deve ser reduzida a fim de avaliar as propriedades diastólicas do coração de camundongos. As funções vitais do animal devem ser cuidadosamente observados para evitar falência hemodinâmica e da morte. Por outro lado, para medições de função sistólica usando modelo M-ecocardiografia taxas, coração abaixo de 400 batimentos por minuto pode causar diastólica final diâmetros a aumentar devido ao enchimento aumento do VE.

* O software necessário é Vevo software incluindo B-Mode aplicação, aplicação da onda de pulso Doppler e análise cardiovascular pacote de ferramentas.

transthoracic echocardiography in mice

Nos últimos anos, tornaram-se modelos murinos da avenida principal de estudar os mecanismos moleculares da disfunção cardíaca decorrente de alterações na expressão genética. Gene transgênico e métodos de segmentação podem ser usados ​​para gerar ratos com tamanho alterado cardíaca e função,<sup&gt; 03/01</sup&gt; E, como resultado,<em&gt; In vivo</emTécnicas de&gt; são necessários para avaliar seu fenótipo cardíaco. Ecocardiografia transtorácica, o pulso de onda Doppler (PWD), e Doppler tecidual (TDI) pode ser usado para fornecer medições dimensionais do coração do rato e quantificar o grau de sistólica cardíaca diastólica e desempenho. Imagem bidimensional é usado para detectar a anatomia anormal ou movimentos do ventrículo esquerdo, enquanto M-mode echo é usado para a quantificação de dimensões e contratilidade cardíaca.<sup&gt; 4,5</sup&gt; Além disso, PWD é usado para quantificar a velocidade localizadas do fluxo turbulento,<sup&gt; 6</sup&gt; Enquanto TDI é usado para medir a velocidade de movimentação do miocárdio.<sup&gt; 7</sup&gt; Assim, o ecocardiograma transtorácico oferece um método abrangente para a avaliação não invasiva da função cardíaca em camundongos.

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

Transthoracic Echocardiography in Mice

O ecocardiograma transtorácico oferece um método não invasivo para a avaliação da função cardíaca em camundongos. A combinação de ultra-som Doppler e modalidades podem ser usadas para obter medições dimensionais do coração eo fluxo sangüíneo intracardíaco, que juntos fornecem uma avaliação da pressão arterial sistólica cardíaca diastólica e desempenho.

Ecocardiografia transtorácica em Ratos

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

61.5K visualizações.  Baylor College of Medicine (BCM). O ecocardiograma transtorácico oferece um método não invasivo para a avaliação da função cardíaca em camundongos. A combinação de ultra-som Doppler e modalidades podem ser usadas para obter medições dimensionais do coração eo fluxo sangüíneo intracardíaco, que juntos fornecem uma avaliação da pressão arterial sistólica cardíaca diastólica e desempenho.

Vídeo: 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.

Ecocardiografia murino e ultra-sonografia

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

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.

Ecocardiografia Fetal murino

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.

Na medição utero da frequência cardíaca em rato por não invasiva em modo M Ecocardiografia

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.

Avaliação da Estrutura e Função do Ventrículo Direito em modelo de camundongo Pulmonary Artery constrição por Ecocardiografia transtorácica

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.

Guiada por ultra-som transtorácica intramiocárdico Injection em Ratos

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.

Infusões artéria carótida para farmacocinéticas e farmacodinâmicas Análise de taxanos em Ratos

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.

Transtorácica salpico de rastreamento A ecocardiografia para a avaliação quantitativa do Ventrículo Esquerdo do miocárdio Deformação

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.

Murino Ecocardiografia de Esquerda Atrium, Aorta, ea artéria pulmonar

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 no 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.