The authors have nothing to disclose.

プロトコルは、ワシントン大学の施設内動物管理使用委員会のガイドラインに従います。 1.手術手順およびイメージングのための準備<ol><li> TACまたは偽手術の対象とC57BL / 6マウスは、以前に10を説明しました。 </li><li>一週間TACまたは偽手術後、1リットル/分のO 2を混合し、2％イソフルランで誘導チャンバ内でマウスを麻酔。つま先や尾のピンチに無反応により適切な麻酔を確認してください。麻酔下ながら乾燥を防ぐために、目に獣医の軟膏を使用してください。脱毛クリームを適用することにより、胸毛を削除してください。 70％エタノールでマウスの皮膚を消毒します。 </li><li>仰臥位で動物取扱プラットフォームにマウスを固定します。 1リットル/分のO 2と混合した1％イソフルラン-麻酔の安定したレベルを維持するために、0.5を提供するためにノーズコーンを使用しています。 </li><li>マウスの足に電極ゲルを適用し、電極パッドにそれらをテープ。 </li><li>体温を監視するための直腸プローブを挿入します。加熱パッドまたはランプを経由して37℃の体温を維持。 </li><li>マウス胸、心臓を覆う主領域に予熱した超音波ゲルの層を適用します。注：超音波ゲルを除去し、イメージング処理後、滅菌ガーゼでマウスを乾かします。 </li></ol>大動脈弓ビューで、[使用するBモードとドップラーイメージングは​​、横大動脈狭窄を評価します<ol><li>大動脈、主要幹線分岐し、狭窄部位を可視化するために、大動脈弓のビューを取得するためにBモードの設定を使用します。 <ol><li>左側臥位にマウスを回転させることが可能な限りプラットフォームの左側を傾けます。垂直位置で待機することにより、超音波トランスデューサを持ち、ノッチがマウスのあごに向いて、右傍胸骨ラインに沿って胸の上に置きます。注：transdを下げたときに、マウスの胸部を圧縮しないでください。ucer;圧力の最小量が必要とされます。 </li><li>肩甲骨のレベルでトランスデューサを傾け、大動脈弓が見えてくるまで少し時計回りに回転。腕頭動脈（IA）および左総頸動脈（LCCA）（ 図1）の分岐との間に配置される横方向の大動脈狭窄部位を観察します。 注：いいえくびれは、偽手術マウスでは検出されませんでした。 </li></ol></li><li>狭窄サイト全体の血流の方向と速度を監視するために、カラードプラモードに切り替えるには、ワークステーションの「カラードップラー」ボタンをクリックします。 「シネストア」ボタンをクリックして画像を取得し、保存します。 </li><li>最高速度で狭窄ジェットを検索するための狭窄部位のすぐ遠位波ドプラモード、および場所のサンプルボリューム（破線のカーソルボックス）パルスに切り替えるに「PWドップラー」ボタンをクリックし、「PWド​​ップラー」ボタンをクリックしてください大動脈FLの波形を取得しますOWとメジャーピーク速度（ 図2）。 </li><li>圧力勾配= 4×V maxの2：変更されたベルヌーイの式を用いて狭窄サイト全体の圧力勾配を計算します。唯一の更なる分析のために40〜80 mmHgの範囲の圧力勾配をマウスに含まれています。 </li></ol>傍胸骨長軸ビューで、[使用するBモードとMモードイメージングは​​、心臓寸法及び収縮を評価します<ol><li>マウスがプラットフォーム上で仰臥位で横たわっていると、ノッチは、マウスの頭を指している垂直な方法でトランスデューサーを保持します。左胸骨傍のラインに胸部平行にトランスデューサを下げ、30°反時計回りに回転させます。 </li><li>心の完全長軸「サジタル」ビューを得るために、Bモードイメージングを使用してください。トランスデューサの角度を調整し、左心室、室内隔壁、および右心室壁のわずかな部分を可視化する深さに焦点を当てます。 S心臓壁の厚さおよびチャンバ寸法の後の測定用の画像をaveの。このようなIVSまたはLVAW、LVID、およびLVPWなどの選択パラメータは、「心臓パッケージ」を使用して、その後、測定値を得るために、各パラメータに対応する線を描画するには画像をクリックしてください。 </li><li>心臓壁運動パターンを観察し、無動、運動低下、および非同期性を含む可能性運動異常、かどうかを確認します。 注：無動と運動低下は、心臓壁の動きの完全および部分的な損失を示し、それぞれ。非同期は、不規則な、まとまりのない心臓壁の動きを示しています。 </li><li>乳頭筋のレベルでLVの壁に垂直にMモード、場所Mモードカーソルに切り替えて、心臓の寸法および短縮率（ 図3）の後の測定のための画像を取得します。 </li></ol>傍胸骨短軸ビュー、心臓形態と機能を評価するために使用するBモードとMモードイメージング4. <ol><li>金曜日オム傍胸骨長軸ビューは、トランスデューサ90°時計回りに回転させることにより、胸骨傍短軸像を得ます。はっきりと見えると右（2と4時の位置）に位置する乳頭筋の両方で、Bモードで心臓の水平断面「横」ビューを提供するために、トランスデューサを調整します。 </li><li> Mモードに切り替えて、左心室のミッドレベルでMモードの軸を配置します。心臓壁の厚さ、チャンバーの寸法、および短縮率（ 図4）の後の測定のために画像を取得して保存。 IVSまたはLVAW、LVID、およびLVPW含む「心臓パッケージ」、SAXでの選択パラメータ（短軸）を使用し、測定値を得るために、各パラメータに対応する線を描画するには画像をクリックしてください。 注：ここで得られた測定値は、傍胸骨長軸ビュー（ 図5）で得られたものと密接に相関するはずです。 </li></ol>アピカル四腔像、使用5.収縮期および拡張期機能を評価するためにドップラーイメージング<ol><li>画面下部の心房と左と右の両方の心室を視覚化するために心尖部四腔像を取得します。 Bモードでは、短軸像から、ダウン角にマウスの頭を、プラットフォームの左上隅を傾け、マウスの右の肩に向けてトランスデューサを向けます。これは頂点に向かって見上げる心の「冠状」ビューを達成するために本質的です。 </li><li> Bモードで僧帽弁を可視化し、カラードプラモードに切り替えて、僧帽弁の先端に試料容量（破線カーソルボックス）を配置します。 </li><li>僧帽弁を横切る流れのパターンを評価するためにPWドプラモードに切り替えます。僧帽弁血流の方向にドップラープローブカーソルを平行に合わせます。ピーク速度（ 図6）を決定するためにプローブの角度20°未満を使用してください。 </li><li>後で測定のための画像を保存します。 「心臓パッケージ」を使用し、選択して &quot;MV流れ。「各パラメータをクリックして、測定値を得るために、対応する線を描画可能な測定は、次のとおりです。ピークE速度（初期のアクティブ心室弛緩を充填）、速度（心房収縮と後半充填）ピーク、僧帽弁等容性弛緩と収縮時間（IVRTをし、それぞれIVCT）、および駆出時間（ET）。 </li><li> MPI =（IVCT + IVRT）/ ETにより心筋の性能指数（MPI）を計算します。 </li></ol>動物の6.術後の治療<ol><li>必要なときに腹腔内手術用動物に鎮痛および/または滅菌生理食塩水を与えます。 </li><li>動物が腹臥位に加熱パッド上で回復させます。それは胸骨横臥位を維持するのに十分な意識を取り戻したまで無人の動物を放置しないでください。完全に回復するまで、他の動物の会社に手続きを経た動物を返さないでください。 </li></ol>

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

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

心エコー検査は、広く心疾患2,6の齧歯類モデルにおいて心機能を評価するために使用されてきました。このような圧力-容積ループ測定11などの侵襲的または端末の方法論などに比べると、ex vivoでの心臓12は 、心エコー検査は、生きている動物で進行中の心臓の構造的および機能的変化を評価するための強力な、非侵襲的なツールを提供して取り組んでいます。...

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

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

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

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

図1は、偽（ 図1A）に供したマウスの心臓またはTAC手術（ 図1B）の大動脈弓図のBモード画像を示しています。大動脈弓、腕頭動脈は、総頸動脈を左、および左鎖骨下動脈が示されています。大動脈狭窄は、TACにはっきりと見えることに注意してくださいが、心を偽ません。大動脈のビューからのカラードップラー画像は、 ?...

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

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

このプロトコルの目的は、非侵襲的B-およびMモード心エコー法およびカラー/脈波ドップラーイメージングを用いて、横方向の大動脈狭窄によって作成された心臓病のマウスモデルにおいて心臓の構造的および機能的変化を評価することです。

心臓形態学的および心エコーイメージングによって横大動脈狭窄のマウスモデルにおける機能の変更の評価

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

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

Research

JoVE Journal

Medicine

18.1K ビュー.  University of Washington. このプロトコルの目的は、非侵襲的B-およびMモード心エコー法およびカラー/脈波ドップラーイメージングを用いて、横方向の大動脈狭窄によって作成された心臓病のマウスモデルにおいて心臓の構造的および機能的変化を評価することです。 

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

Transthoracic Echocardiography in Mice

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

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

マウスにおける経胸壁心エコー

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

医学

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.

マウス心エコー検査と超音波イメージング

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

Ultrasonic Assessment of Myocardial Microstructure

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

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

心筋微細構造の超音波評価

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

Assessment of Right Ventricular Structure and Function in Mouse Model of Pulmonary Artery Constriction by Transthoracic Echocardiography

Emerging clinical data support the notion that RV dysfunction is critical to the pathogenesis of cardiovascular disease and heart failure1-3. Moreover, the RV is significantly affected in pulmonary diseases such as pulmonary artery hypertension (PAH). In addition, the RV is remarkably sensitive to cardiac pathologies, including left ventricular (LV) dysfunction, valvular disease or RV infarction4. To understand the role of RV in the pathogenesis of cardiac diseases, a reliable and noninvasive method to access the RV structurally and functionally is essential.
A noninvasive trans-thoracic echocardiography (TTE) based methodology was established and validated for monitoring dynamic changes in RV structure and function in adult mice. To impose RV stress, we employed a surgical model of pulmonary artery constriction (PAC) and measured the RV response over a 7-day period using a high-frequency ultrasound microimaging system. Sham operated mice were used as controls. Images were acquired in lightly anesthetized mice at baseline (before surgery), day 0 (immediately post-surgery), day 3, and day 7 (post-surgery). Data was analyzed offline using software.
Several acoustic windows (B, M, and Color Doppler modes), which can be consistently obtained in mice, allowed for reliable and reproducible measurement of RV structure (including RV wall thickness, end-diastolic&#160;and end-systolic dimensions), and function (fractional area change, fractional shortening, PA peak velocity, and peak pressure gradient) in normal mice and following PAC.
Using this method, the pressure-gradient resulting from PAC was accurately measured in real-time using Color Doppler mode and was comparable to direct pressure measurements performed with a Millar high-fidelity microtip catheter. Taken together, these data demonstrate that RV measurements obtained from various complimentary views using echocardiography are reliable, reproducible and can provide insights regarding RV structure and function. This method will enable a better understanding of the role of RV cardiac dysfunction.

Right ventricle (RV) dysfunction is critical to the pathogenesis of cardiovascular disease, yet limited methodologies are available for its evaluation. Recent advances in ultrasound imaging provide a noninvasive and accurate option for longitudinal RV study. Herein, we detail a step-by-step echocardiographic method using a murine model of RV pressure overload.

経胸壁心エコー検査による肺動脈狭窄のマウスモデルにおける右室の構造と機能の評価

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

Transverse Aortic Constriction in Mice

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

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

マウスの横大動脈狭窄

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

生物学

Echocardiographic Approaches and Protocols for Comprehensive Phenotypic Characterization of Valvular Heart Disease in Mice

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in rodents, with detailed descriptions of the appropriate methods for anesthesia, the echocardiographic windows used, the imaging planes and probe orientations for image acquisition, the methods for data analysis, and the limitations of emerging technologies for the evaluation of cardiac and valvular function. Importantly, we also highlight several future areas of research in cardiac and heart valve imaging that may be leveraged to gain insights into the pathogenesis of valve disease in preclinical animal models. We propose that using a systematic approach to evaluating cardiac and heart valve function in mice can result in more robust and reproducible data, as well as facilitate the discovery of previously underappreciated phenotypes in genetically-altered and/or physiologically-stressed mice.

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

マウスの弁膜症の包括的表現型の特徴のための心エコーアプローチとプロトコル

The aim of this manuscript and accompanying video is to provide an overview of the methods and approaches used for imaging heart valve function in ...

Minimally Invasive Transverse Aortic Constriction in Mice

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

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

マウスにおける低侵襲横大動脈狭窄

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

Echocardiographic and Histological Examination of Cardiac Morphology in the Mouse

An increasing number of genetically modified mouse models has become available in recent years. Moreover, the number of pharmacological studies performed in mice is high. Phenotypic characterization of these mouse models also requires the examination of cardiac function and morphology. Echocardiography and magnetic resonance imaging (MRI) are commonly used approaches to characterize cardiac function and morphology in mice. Echocardiographic and MRI equipment specialized for use in small rodents is&#160;expensive and requires a dedicated space. This protocol describes cardiac measurements in mice using a clinical echocardiographic system with a 15 MHz human vascular probe. Measurements are performed on anesthetized adult mice. At least three image sequences are recorded and analyzed for each animal in M-mode in the parasternal short-axis view. Afterwards, cardiac histological examination is performed, and cardiomyocyte diameters are determined on hematoxylin-eosin- or wheat germ agglutinin (WGA)-stained paraffin sections. Vessel density is determined morphometrically after Pecam-1 immunostaining. The protocol has been applied successfully to pharmacological studies and different genetic animal models under baseline conditions, as well as after experimental myocardial infarction by the permanent ligation of the left anterior descending coronary artery (LAD). In our experience, echocardiographic investigation is limited to anesthetized animals and is feasible in adult mice weighing at least 25 g.

Echocardiographic examination is frequently used in mice. Expensive high-resolution ultrasound devices have been developed for this purpose. This protocol describes an affordable echocardiographic procedure combined with histological morphometric analyses to determine cardiac morphology.

マウスの心臓形態の心エコー検査・組織学的検討

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

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

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

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

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

A Modified Technique for Transverse Aortic Constriction in Mice

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

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

マウスにおける横行大動脈狭窄の修正技術

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