This work was supported by grants from the National Natural Science Foundation of China (81770271; to Y, Liao), the Joint Funds of the National Natural Science Foundation of China (U1908205; to Y, Liao), and the Municipal Planning Projects of Scientific Technology of Guangzhou (201804020083; to Dr Liao).

All procedures were carried out following the guidelines of the Care and Use of Laboratory Animals published by the US National Institutes of Health (NIH Publication No. 85-23, revised in 1996). C57BL/6J male mice (8&#8211;10 weeks, 20&#8211;25 g) were provided by the Animal Center of South Medical University.
1. Preoperative preparation
<ol>
	<li>Pinch off the tip of a 25 G needle with a needle holder and blunt it with a hard object like the holder.</li>
	<li>Pass a 5&#8211;0 absorbable suture through the needle and then curve it to 90&#176; with a holder13. 
	NOTE: According to different research purposes, investigators could select absorbable lines with different absorption time. In this protocol, we used a 2-week absorbable suture to constrict the aortic arch.</li>
	<li>Curve another 25 G needle to 120&#176; and smoothen the tip with a holder to be used as a spacer in the ligation step. 
	NOTE: A 25 G needle was used as a spacer for mice having body weight (BW) &#62;25 g. Use a 26 G needle for mice with 19&#8211;24 g BW.</li>
	<li>Disinfect the operative site with 75% alcohol.</li>
	<li>Adjust the heating pad temperature to 37 &#176;C.</li>
	<li>Prepare sterilized surgical instruments (including 1 ophthalmic scissors, 1 micro scissors, 2 microsurgical elbow tweezers, 1 needle holder, and 1 micro needle holder).</li>
</ol>
2. Induction of anesthesia and shaving
<ol>
	<li>Anesthetize a mouse by intraperitoneal injection of a mixture of xylazine (5 mg/kg) and ketamine (100 mg/kg) diluted in saline solution (0.9% NaCl). Confirm complete anesthetization with the negative pedal withdrawal reflex.</li>
	<li>Keep the mouse in supine position by fixing the incisors with a suture and fixing the limbs with adhesive tapes.</li>
	<li>Apply depilatory cream to remove hair on its neck and xiphoid. Disinfect the area with iodine followed by 75% alcohol.</li>
</ol>
3. Surgery
<ol>
	<li>Make an incision over 10 mm at the midline position between supra-sternal notch and chest with a scalpel. Then, separate the skin and the superficial fascia.</li>
	<li>Identify the first intercostal space by counting the ribs from the sternal angle. Perform the incision in the first intercostal space and as close as possible to the sternum. Bluntly penetrate it with elbow tweezers to open this space.</li>
	<li>Gently separate the parenchyma and the thymus until the transverse aortic arch is visible. 
	NOTE: Do not damage the parietal pleura to avoid pneumothorax.</li>
	<li>Pass the 5&#8211;0 absorbable suture under the aortic arch between the brachiocephalic artery and the left common carotid artery with a latch needle14. Please make sure that the brachiocephalic artery, the left common carotid artery, and the left subclavian artery are visible in the operation field.</li>
	<li>Place the spacer, prepared in step 1.3, on the transverse aorta and perform a double knot on the spacer with the suture in step 3.4. 
	NOTE: The tip of the spacer must be blunt to avoid damaging the transverse aorta while removing it.</li>
	<li>Remove the spacer quickly but gently, and then cut the ends of the suture.</li>
	<li>Close the first intercostal space and the skin using 5&#8211;0 nylon sutures. Disinfect the skin again with 75% alcohol.</li>
	<li>Place the mouse on the heating pad to promote recovery. Inject buprenorphine (0.1 mg/kg, q12h) intraperitoneally for the first 3 days after the surgery.</li>
	<li>Return the mouse to the cage in a 12 h light/dark cycle room when it recovers consciousness.</li>
	<li>Perform sham surgery identical to all the above steps but without the constriction (step 3.5).</li>
	<li>Perform surgery for the silk suture group, identical to all the above steps but using a 5&#8211;0 silk suture in step 1.2.</li>
</ol>
4. Echocardiographic assessment of successful ligation and measurements
<ol>
	<li>Perform echocardiographic assessment on the Day (D) 7 after surgery.</li>
	<li>Anesthetize the mouse with 3% isoflurane through inhalation for induction, and 1.5% for maintaining the depth of anesthesia, with a 0.5&#8211;1 L/min oxygen flow rate.</li>
	<li>Place the mouse in supine position on the platform, maintained at 37 &#176;C, and tape its limbs to the electrode.</li>
	<li>Remove the chest hair with a depilatory cream and apply ultrasonic coupling agent to the mouse&#8217;s chest.</li>
	<li>Assess transverse aortic constriction with a 30 MHz probe.
	<ol>
		<li>Tilt the platform to the far left. Keep the probe in vertical position and lower it on the chest along the right parasternal line. Then, manipulate X-axis and Y-axis under B-mode until the aortic arch is clearly visible.</li>
		<li>Locate the constriction by B-mode to obtain the aortic arch view11. Use the color Doppler mode and pulsed wave to measure the peak flow velocity and select mice with a velocity of more than 3,000 mm/s as the TAC group (values are based on preliminary experiments).</li>
		<li>Calculate the pressure gradient according to the modified version of Bernoulli&#39;s equation11: 
		pressure gradient = 4 x Vmax2. 
		NOTE: The ideal pressure gradient for transverse aortic constriction model ranges from 40&#8211;80 mmHg11.</li>
		<li>Save the data and images using Cine Store and Frame Store.</li>
	</ol>
	</li>
	<li>Assess dimensions and contractility of left ventricular (LV) with a 30 MHz probe.
	<ol>
		<li>Reset the platform to the horizontal position. Keep the probe at 30&#176; counterclockwise relative to the left parasternal line.</li>
		<li>Use B-mode and manipulate X and Y to obtain a clear and full-long axis view of the heart.</li>
		<li>Press M-mode to show the indicator line. Acquire images with Cine Store and Frame Store for later measurement of the LV chamber dimension, fractional shortening, and LV wall thickness.</li>
	</ol>
	</li>
	<li>Once done, stop isoflurane inhalation and allow the mouse to recover from anesthesia. Then, return the animal to its cage in a 12 h light/dark cycle room.</li>
	<li>On D14 and D28 after surgery, repeat the above steps to measure the cardiac parameters and then harvest the heart for histological studies.</li>
</ol>

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The authors have nothing to disclose.

There is still a vastly underexplored area in cardiac non-ischemic preconditioning. Based on our previous studies, we switched to using absorbable sutures to improve the myocardial hypertrophic preconditioning model.
In previous reports, many investigators used silk suture to constrict the aortic arch8,14,15. Silk suture was easily available and was often used for surgical wound suture, tissue ligatio...

Ischemic preconditioning is a phenomenon that induces brief non-lethal episodes of ischemia and reperfusion to the heart and has the capacity to dramatically reduce myocardial injury1. Given the obvious clinical implications of ischemic preconditioning, such as limiting myocardial infarct size2 and suppressing ventricular tachyarrhythmias after myocardial revascularization3, there have been lots of research to dissect the mechanisms underlying cardio-protective effects induced by preconditioning4,5. In contrast, other non-ischemic types of preconditioning have received relatively little attention. Cardiac hypertrophy may be blunted in patients with aortic stenosis undergoing aortic valve replacement6. Wherever the state of pathological myocardial hypertrophy exists, the principle of preconditioning is rarely reported.
In 1991, Rockman et al. firstly established a mouse model of left ventricular hypertrophy by transverse aortic constriction (TAC)7. By operating TAC twice in mice, we have previously proved that myocardial hypertrophic preconditioning (MHP) leads to transient hypertrophic stimulation in the heart thereby making the heart more resistant to sustained hypertrophic stress in the future8. The characteristics of the MHP model have been validated by ultrasound biomicroscope and hemodynamic assessment9. Key points in constructing the model was to perform thoracotomy three times, TAC for a week, debanding for a week, and secondary TAC for 6 weeks. However, debanding could cause bleeding, which made it difficult to be mastered by novices and difficult to be popularized. In addition, it is also a technical challenge to intubate mice. Improper intubation could cause tracheal injury, pneumothorax, and even death in mice. So, it is necessary and valuable to improve some procedures while constructing the MHP model.
To reduce the difficulty of the model and increase its success, we switched to absorbable sutures for the first TAC and monitored the model&#39;s success by measuring pressure gradient across the aortic constriction under echocardiography10. Based on our preliminary experiment, it would be difficult to induce sufficient myocardial hypertrophy in mice with too low-pressure gradient, while mice with too high-pressure gradient would develop acute heart failure or even die. The ideal pressure gradient for the model ranges from 40&#8211;80 mmHg11. In addition, this experiment did not rely on a ventilator, which could effectively avoid ventilator-associated technical manipulation and injury12.

<table><tbody><tr><td>Absorbable suture (5-0)</td><td>Shandong Kang Lida Medical Products Co., Ltd</td><td>5-0</td><td>Ligation</td></tr><tr><td>Animal ultrasound system VEVO2100</td><td>Visual Sonic</td><td>VEVO2100</td><td>Echocardiography</td></tr><tr><td>Cold light illuminator</td><td>Olympus</td><td>ILD-2</td><td>Light</td></tr><tr><td>Heat pad- thermostatic surgical system (ALC-HTP-S1)</td><td>SHANGHAI ALCOTT BIOTECH CO</td><td>ALC-HTP-S1</td><td>Heating</td></tr><tr><td>Isoflurane</td><td>RWD life science</td><td>R510-22</td><td>Inhalant anaesthesia</td></tr><tr><td>Matrx VIP 3000 Isofurane Vaporizer</td><td>Midmark Corporation</td><td>VIP 3000</td><td>Anesthetization</td></tr><tr><td>Medical nylon suture (5-0)</td><td>Ningbo Medical Needle Co.</td><td>5-0</td><td>Close the skin</td></tr><tr><td>Pentobarbital sodium salt</td><td>Merck</td><td>25MG</td><td>Anesthetization</td></tr><tr><td>Precision electronic balance</td><td>Denver Instrument</td><td>TB-114</td><td>Weighing sensor</td></tr><tr><td>Self-made spacer</td><td></td><td></td><td>25-gauge needle</td></tr><tr><td>Silk suture (5-0)</td><td>Yangzhou Yuankang Medical Devices Co., Ltd.</td><td>5-0</td><td>Ligation</td></tr><tr><td>Small animal microsurgery equipment</td><td>Napox</td><td>MA-65</td><td>Surgical instruments</td></tr><tr><td>Transmission Gel</td><td>Guang Gong pai</td><td>250ML</td><td>Echocardiography</td></tr><tr><td>Veet hair removal cream</td><td>Reckitt Benchiser</td><td>RQ/B 33 Type 2</td><td>Remove hair of mice</td></tr><tr><td>Vertical automatic electrothermal pressure steam sterilizer</td><td>Hefei Huatai Medical Equipment Co.</td><td>LX-B50L</td><td>Auto clean the surgical instruments</td></tr></tbody></table>

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.

In this study, we randomly divided 45 mice into three groups, the sham, the silk suture group, and the absorbable suture group (the number of each group on D0 (baseline), D14, and D28 after TAC was 15, 10, and 5, respectively). On D7, D14, D21, and D28 after the surgery, the constricted peak velocity was determined by echocardiography. We found that the blood flow velocity at the constriction was still greater than 3,000 mm/s in the second week after TAC even though an absorbable suture had been used to constrict the aor...

Watch this Scientific Journal Video about Operating Transverse Aortic Constriction with Absorbable Suture to Obtain Transient Myocardial Hypertrophy at JoVE.com

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

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.

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

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6.2K Views.  Southern Medical University. Dit protocol presenteert een verbeterde methode om voorbijgaande myocardhypertrofie met absorbeerbare hechting te verkrijgen, waarbij de afname van linkerventrikelhypertrofie wordt gesimuleerd na het verwijderen van drukoverbelasting. Het kan waardevol zijn voor de studies naar myocardhypertrofische conditionering.

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

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

Ascending aortic constriction is the most common and successful surgical model for creating pressure overload induced cardiac hypertrophy and heart failure. Here, we describe a detailed surgical procedure for creating pressure overload and cardiac hypertrophy in rats by constriction of the ascending aorta using a small metallic clip. After anesthesia, the trachea is intubated by inserting a cannula through a half way incision made between two cartilage rings of trachea. Then a skin incision is made at the level of the second intercostal space on the left chest wall and muscle layers are cleared to locate the ascending portion of aorta. The ascending aorta is constricted to 50&#8211;60% of its original diameter by application of a small sized titanium clip. Following aortic constriction, the second and third ribs are approximated with prolene sutures. The tracheal cannula is removed once spontaneous breathing was re-established. The animal is allowed to recover on the heating pad by gradually lowering anesthesia. The intensity of pressure overload created by constriction of the ascending aorta is determined by recording the pressure gradient using trans-thoracic two dimensional Doppler-echocardiography. Overall this protocol is useful to study the remodeling events and contractile properties of the heart during the gradual onset and progression from compensated cardiac hypertrophy to heart failure stage.

We describe a stepwise procedure for creating pressure overload and left ventricular hypertrophy in Wistar rats by constriction of the ascending aorta using a small metallic clip. This model is extensively used for studying remodeling changes during cardiac hypertrophy and for identifying and evaluating strategies for regression of such changes.

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

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.

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.

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.

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.

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

Studying Left Ventricular Reverse Remodeling by Aortic Debanding in Rodents

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, mice undergo RR upon removal of the aortic constriction. In this paper, we describe a step-by-step procedure to perform a minimally invasive surgical aortic debanding in mice. Echocardiography was subsequently used to assess the degree of cardiac hypertrophy and dysfunction during LV remodeling and RR and to determine the best timing for aortic debanding. At the end of the protocol, terminal hemodynamic evaluation of the cardiac function was conducted, and samples were collected for histological studies. We showed that debanding is associated with surgical survival rates of 70-80%. Moreover, two weeks after debanding, the significant reduction of ventricular afterload triggers the regression of ventricular hypertrophy (~20%) and fibrosis (~26%), recovery of diastolic dysfunction as assessed by the normalization of left ventricular filling and end-diastolic pressures (E/e&#39;&#160;and LVEDP). Aortic debanding is a useful experimental model to study LV RR in rodents. The extent of myocardial recovery is variable between subjects, therefore, mimicking the diversity of RR that occurs in the clinical context, such as aortic valve replacement. We conclude that the aortic banding/debanding model represents a valuable tool to unravel novel insights into the mechanisms of RR, namely the regression of cardiac hypertrophy and the recovery of diastolic dysfunction.

Here we describe a step-by-step protocol of surgical aorta debanding in the well-established mice model of aortic-constriction. This procedure not only allows studying the mechanisms underlying the left ventricular reverse remodeling and regression of hypertrophy but also to test novel therapeutic options that might accelerate myocardial recovery.

To better understand the left ventricular (LV) reverse remodeling (RR), we describe a rodent model wherein, after aortic banding-induced LV remodeling, ...

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.

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

Ascending Aortic Banding for Studying Pressure-Overload Induced Heart Failure

A Minimally Invasive Model of Aortic Stenosis in Swine

Large animal models of heart failure play an essential role in the development of new therapeutic interventions due to their size and physiological similarities to humans. Efforts have been dedicated to creating a model of pressure-overload induced heart failure, and ascending aortic banding while still supra-coronary and not a perfect mimic of aortic stenosis in humans, closely resembling the human condition.
The purpose of this study is to demonstrate a minimally invasive approach to induce left ventricular pressure overload by placing an aortic band, precisely calibrated with percutaneously introduced high-fidelity pressure sensors. This method represents a refinement of the surgical procedure (3Rs), resulting in homogenous trans-stenotic gradients and reduced intragroup variability. Additionally, it enables swift and uneventful animal recovery, leading to minimal mortality rates. Throughout the study, animals were followed for up to 2 months after surgery, employing transthoracic echocardiography and pressure-volume loop analysis. However, longer follow-up periods can be achieved if desired. This large animal model proves valuable for testing new drugs, particularly those targeting hypertrophy and the structural and functional alterations associated with left ventricular pressure overload.

Author Spotlight: Development of a Minimally Invasive Large-Animal Model for Reliable and Reproducible Cardiovascular Research 

This protocol describes a minimally invasive surgical procedure for ascending aortic banding in swine.

Large animal models of heart failure play an essential role in the development of new therapeutic interventions due to their size and physiological ...

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.

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

Biology

Generating Murine Model of Myocardial Infarction: A Surgical Procedure for Permanent Ligation of Left Anterior Descending Coronary Artery in Mouse Model

Source: Lugrin, J. et al. <a href="https://www.jove.com/video/59591" target="_blank">Murine Myocardial Infarction Model using Permanent Ligation of Left Anterior Descending Coronary Artery</a>. J. Vis. Exp. (2019)
In this video, we describe a surgical procedure to generate a mouse model of myocardial infarction by permanently ligating the left anterior descending coronary artery.

Source: Lugrin, J. et al. Murine Myocardial Infarction Model using Permanent Ligation of Left Anterior Descending Coronary Artery. J. Vis. Exp. (2019)
In ...

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

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