Name: transplantation of pulmonary valve using a mouse model of heterotopic heart transplantation
Uploaded: 2014-07-23T15:00:00.000+00:00
Duration: 10 min 56 s
Description: Watch this Scientific Journal Video about Transplantation of Pulmonary Valve Using a Mouse Model of Heterotopic Heart Transplantation at JoVE.com

This work was supported, in part, by a grant from the NIH (RO1 HL098228) to CKB.

Note: All animal procedures were approved by the Nationwide Children&#8217;s Hospital Institutional Animal Care and Use Committee.
1. Pulmonary Heart Valve Harvest from a Heart Valve Donor Mouse
<ol>
	<li>Autoclave all the surgical tools before the surgery: 1x fine scissors, 3x micro forceps, 2x micro vascular clamps, 1x clamp applying forceps, 1x micro needle holder, 1x spring scissors, 1x retractor.</li>
	<li>A 6-8 week old female C57BL/6 mouse is used as a pulmonary heart valve donor. Remove the mouse from its cage and weigh it, then euthanize with a ketamine/xylazine cocktail (Ketamine, 200 mg/kg and xylazine, 20 mg/kg, IP) overdose.</li>
	<li>Clip the chest area and place the mouse in a dorsal recumbence position on a pad. Then make the thoracotomy. Expose the heart, make a small cut on the right atrium, and perfuse the left ventricle with ice cold saline.</li>
	<li>Bluntly dissect the pulmonary artery (PA) from the ascending aorta. Cut out the pulmonary valve (PV) along with 2 mm cuff of pulmonary artery. Dispose of the remainder of the heart.</li>
	<li>Store the PV in cold heparin and saline solution (100 units/ml). Note: The PV can be kept in the solution for two hours before transplantation to the donor heart.</li>
</ol>
2. Donor Heart Preparation
<ol>
	<li>A 6-8 week old female C57BL/6 mouse is used as a heart donor. Remove the mouse from its cage and weigh it, then euthanize with a ketamine/xylazine cocktail (ketamine, 200 mg/kg and xylazine, 20 mg/kg, IP) overdose. This is a terminal procedure.&#160;</li>
	<li>Clip the chest area and place the mouse in a dorsal recumbence position on a pad. Then make the thoracotomy. Bluntly separate the heart, inferior vena cava (IVC), superior vena cava (SVC), ascending aorta, PA, and pulmonary vein. Perfuse the IVC with ice cold sterile saline.</li>
	<li>Ligate the IVC, SVC, and pulmonary vein with 6-0 silk suture then cut superior to the ligatures.</li>
	<li>Cut the aorta and PA with 2 mm cuff.</li>
	<li>Cut out the PV and dispose of it.</li>
</ol>
3. Heart Valve Transplantation onto a Donor Heart
<ol>
	<li>Immediately after step 2.5, place the heart valve from step 1.5&#160;into the donor heart and orient the heart valve.</li>
	<li>Secure the PV with a stitch on the right side of the valve using 10-0 monofilament sutures on tapered needles and start to suture continuously with 5-6 stiches from the other side of the PV.</li>
	<li>After finishing the front side, rotate the heart horizontally and start to suture the back side of the PV onto the donor heart.</li>
	<li>Store the heart in a cold sterile&#160;heparin/saline solution. Note: The donor heart can be kept in the solution for two hours before implantation to the recipient mouse.</li>
</ol>
4. Heterotopic Heart Transplantation on to a Recipient Mouse
<ol>
	<li>A 6-8 week old female C57BL/6 mouse was used as a recipient. Remove the mouse from its cage and weigh it, then anesthetized with ketamine/xylazine cocktail (ketamine, 100 mg/kg and xylazine 10 mg/kg). Ketoprofen (5 mg/kg) is used as preanesthesia analgesic.</li>
	<li>After checking the level of sedation by tail pinching, clip the abdominal and chest hair. Lubricate the eyes with sterile ophthalmic ointment, and place the mouse in a dorsal recumbence position on a pad. Disinfect the abdomen with betadine and alcohol pads. Then cover the mouse with a sterile drape and expose the incision area only.</li>
	<li>Make a midline laparotomy incision from below the xyphoid to the suprapubic region, and insert a self retaining retractor. Wrap the intestines in saline moistened gauze. Bluntly define the infrarenal aorta and vena cava.</li>
	<li>Place two 6-0 silk sutures proximally and distally around the aorta and IVC to restrain blood circulation.</li>
	<li>Place the donor heart on the right side of the abdominal aorta and cover it with sterile gauze. Moisturize it with saline.</li>
	<li>Make an aortotomy in the abdominal aorta using a 30 G needle and extend the opening with scissors to the size of the donor aorta.</li>
	<li>Perform an end-to side anastomosis using sterile 10-0 monofilament sutures on tapered needles. Secure the donor aorta with one stitch on proximal end of the opening in the abdominal aorta and start to suture continuously with 4-5 stiches from the distal end of the abdominal aorta.</li>
	<li>Flip the heart to the left side, cover it with saline infused gauze, and start to suture continuously with 4-5 stiches from the distal end of the abdominal aorta.</li>
	<li>Make a venotomy in the IVC using a 30 G needle and extend the opening to the size of the donor pulmonary artery.</li>
	<li>Perform an end to side anastomosis using sterile 10-0 monofilament sutures on tapered needles. Secure the donor PA with one stitch on the proximal end of the opening in the IVC and start to suture continuously with 4-5 stiches from the distal end of the inferior vena cava. This time, because the aorta is in the way, make sure suturing of the left wall of the donor&#8217;s PA is on the inside of the IVC.</li>
	<li>Flush the IVC lumen with heparin and saline solution (100 units/ml). Close the right wall of the donor PA and recipient IVC by suturing them continuously to the distal end.</li>
	<li>Remove the distal ligature and control the hemorrhage by applying a topical absorbable sterile hemostat agent. When the hemorrhage stops completely, remove the proximal suture and control the hemorrhage the same way.</li>
	<li>Return the intestines and close the abdominal musculature and skin in two layers using a 6-0 black polyamide monofilament suture.</li>
	<li>Inject 0.5 ml saline subcutaneously and place the mouse in a recovery cage on a warming pad until the mouse is fully mobile. Upon recovery, return the mouse to a new cage with paper bedding. Give pain medication (Ibuprofen, 30 mg/kg, drinking water) for 48 hr. Do not return an animal that has undergone surgery to the company of other animals until fully recovered.</li>
</ol>

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	<li>Polito, 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=Increased+morbidity+and+mortality+in+very+preterm+VLBW+infants+with+congenital+heart+disease.">Increased morbidity and mortality in very preterm VLBW infants with congenital heart disease.</a> Intens Care Med. 39, 1104-1112 (2013).</li><li>Wren, C., Reinhardt, Z., Khawaja, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Twenty+year+trends+in+diagnosis+of+life+threatening+neonatal+cardiovascular+malformations.">Twenty year trends in diagnosis of life threatening neonatal cardiovascular malformations.</a> Arch Dis Child Fetal. 93, F33-F35 (2008).</li><li>Vacanti, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beyond+transplantation+Third+annual+Samuel+Jason+Mixter+lecture.">Beyond transplantation Third annual Samuel Jason Mixter lecture.</a> Archives of surgery. 123, 545-549 (1960).</li><li>Tudorache, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Orthotopic+replacement+of+aortic+heart+valves+with+tissue-engineered+grafts.">Orthotopic replacement of aortic heart valves with tissue-engineered grafts.</a> Tissue engineering Part A. 19, 1686-1694 (2013).</li><li>van Geldorp, M. W., 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=Patient+outcome+after+aortic+valve+replacement+with+a+mechanical+or+biological+prosthesis+weighing+lifetime+anticoagulant+related+event+risk+against+reoperation+risk.">Patient outcome after aortic valve replacement with a mechanical or biological prosthesis weighing lifetime anticoagulant related event risk against reoperation risk.</a> The Journal of thoracic and cardiovascular surgery. 137, 881-886 (2009).</li><li>El Oakley, R., Kleine, P., Bach, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Choice+of+prosthetic+heart+valve+in+today's+practice.">Choice of prosthetic heart valve in today's practice.</a> Circulation. 117, 253-256 (2008).</li><li>Quinn, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+Models+for+Bench+to+Bedside+Translation+of+Regenerative+Cardiac+Constructs.">Animal Models for Bench to Bedside Translation of Regenerative Cardiac Constructs.</a> Progress in Pediatric cardiology. 35, (2013).</li><li>Shinoka, 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=Tissue+engineering+heart+valves+valve+leaflet+replacement+study+in+a+lamb+model.">Tissue engineering heart valves valve leaflet replacement study in a lamb model.</a> The Annals of thoracic surgery. 60, S513-S516 (1995).</li><li>Sodian, R., 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=Tissue+engineering+of+heart+valves+in+vitro+experiences.">Tissue engineering of heart valves in vitro experiences.</a> The Annals of thoracic surgery. 70, 140-144 (2000).</li><li>Shinoka, 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=Tissue+engineered+heart+valves.+Autologous+valve+leaflet+replacement+study+in+a+lamb+model.">Tissue engineered heart valves. Autologous valve leaflet replacement study in a lamb model.</a> Circulation. 94, II164-II168 (1996).</li><li>Sodian, R., 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=Evaluation+of+biodegradable+three+dimensional+matrices+for+tissue+engineering+of+heart+valves.">Evaluation of biodegradable three dimensional matrices for tissue engineering of heart valves.</a> ASAIO journal (American Society for Artificial Internal Organs. 46, 107-110 (1992).</li><li>Sodian, R., 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=Early+in+vivo+experience+with+tissue-engineered+trileaflet+heart+valves).">Early in vivo experience with tissue-engineered trileaflet heart valves).</a> Circulation. 102, III22-III29 (2000).</li></ol>

We have nothing to disclose.

The mortality rate of this procedure is close to 20%, which was mostly caused by hemorrhage at the PV transplantation site and anastomosis on the donor aorta to the recipient abdominal aorta. In most of the cases, the mortality rate decreases significantly 48 hr post surgery. The survival mice showed strong heart beats and blood flow through the implanted PV. The entire process takes four hours for an experienced micro surgeon. It will take roughly 250 mice to master the technique. The heterotopic heart transplantation is relatively straight forward in comparison to the PV implantation to the donor heart. One of the most critical steps for a successful HV transplantation is harvest of the PV structure from a donor mouse. The PV structure should be transected around 1-2 mm below the valve. If the remaining tissue is too short, anastomosis will be challenging. If the tissue below the PV is too long (i.e. the PA will be too long in comparison to the ascending aorta after implantation), the implanted PA may twist or kink. Another critical step is the anastomosis between the implanted PA and recipient IVC. Since the IVC is very thin, it is extremely easy to tear during suturing.
In this model, the aortic blood comes through the aorta, flows through the coronary arteries, then exits through coronary sinus to the donor RA. So the blood volume to pass through the implanted PV is 5% of the total blood volume in estimation, which is the most significant limitation of this model in studying TEHV. To increase the blood flow though the PV, three additional models were created. First, a third anastomosis was created from the donor RV to the recipient IVC. The third anastomosis can increase blood flow by 10% to 50% of total blood volume. Second, to further increase the blood flow, after placing the third anastomosis, the IVC was ligated proximal to the third anastomosis. This method insured 50% of blood flow through the implanted PV. Third, in order to increase flow through the implanted PV and maintain more physiological circulation, the heart was transplanted with the lungs. This method could increase the flow up to 50% of total blood flow and more importantly, the left ventricle and left atrium maintain their circulation. These different physiological flow models enable us to study how the difference in physiological flow conditions affect the development of neotissue and stenosis in a transplanted heart valve.
Recently, we conducted a pilot study to transplant decellularized HV without cell seeding using the described technique in this paper. The implanted PV showed similar blood flow characteristics as the control, predecellularized transplanted PV. In the future, different types of cells will be seeded to study the neotissue formation and stenosis development of the transplanted HV. Moreover, using transgenic mice, such as green fluorescent protein (GFP) mice or a mouse model of HV disease, the process of neotissue formation can be studied mechanistically by studying the source of cells populating the decellularized or diseased heart valve using immunohistochemistry, which will aid the development of more rationally designed, second generation tissue engineered heart valves. The possibility of using different physiological flow conditions, transgenic mice, decellularized PV implantations, and possible combinations of all three show the versatility and potentially important preclinical utility of this HV transplantation model.

Congenital cardiovascular defects are one of the leading causes of infant mortality in the western world1,2.&#160; Among them, pulmonic valve stenosis and bicuspid aortic valve defects are a frequently occurring form3.&#160; Heart valve replacement surgery is a routine choice of reconstructive surgeries; however, complications including stenosis and calcification of the heart valve, and lifelong dependence on anticoagulants are a significant source of chronic ill health and death4-7. Moreover, the lack of growth potential requires revision surgeries, which further increases the mortality of those young patients4,8,9.
In an attempt to develop a functional replacement heart valve with growth potential, Shinoka et al. seeded autologous cells onto a biodegradable synthetic heart valve8. The synthetic valve transformed to a native heart valve like structure with growth potential. Preliminary large animal studies demonstrated the feasibility of using this methodology to create a functional heart valve10.&#160; However, long term implantation studies demonstrated poor durability due to progressive thickening of the valve neotissue resulting in narrowing of the heart valve. Work from Sodian et al. used the Shinoka methodology, but ultimately replaced the PGA matrix with a biodegradable elastomer, which gave the biomechanical properties of the tissue engineered valve construct a more physiological profile9,11,12. In the in vivo study, despite the success of the implantation, a confluent endothelial cell lining was not formed which could limit the long term success of this scaffold12.
In order to rationally design an improved second generation synthetic heart valve, a murine model of heart valve transplantation was created to investigate the cellular and molecular mechanisms underlying neotissue formation, valve thickening, and stenosis development. Murine models offer a vast array of molecular reagents, including transgenics, which are not readily available in other species7. In this heart valve transplantation model, an ex vivo syngeneic pulmonary heart valve replacement was performed first; and then the heart with the implanted heart valve was implanted heterotopically into a syngeneic host using a microsurgical technique. This model enables heart valve replacement without the need for cardiopulmonary bypass.
In this paper, a detailed explanation of a heart valve harvest, donor heart preparations, heart valve transplantation, and heterotopic heart transplantation is described. The results showed a continuous heartbeat from the donor heart, which was independent of the recipient heartbeat. The blood flow through the implanted pulmonary valve was measured using a high frequency ultrasound system with a pulsed wave Doppler.

<table><tbody><tr><td>DPBS</td><td>Gibco</td><td>14190-144</td><td></td></tr><tr><td>Microscope</td><td>Leica</td><td>M80</td><td></td></tr><tr><td>C57BL/6J (H-2b), Female</td><td>Jackson Laboratories</td><td>664</td><td>8-12 weeks</td></tr><tr><td>Ketamine Hydrochloride Injection</td><td>Hospira Inc.</td><td>NDC 0409-2053</td><td></td></tr><tr><td>Xylazine Sterile Solution</td><td>Akorn Inc.</td><td>NADA# 139-236</td><td></td></tr><tr><td>Ketoprofen</td><td>Fort Dodge Animal Health</td><td>NDC 0856-4396-01</td><td></td></tr><tr><td>Ibuprofen</td><td>PrecisionDose</td><td>NDC 68094-494-59</td><td></td></tr><tr><td>Heparin Sodium</td><td>Sagent Pharmaceticals</td><td>NDC 25021-400</td><td></td></tr><tr><td>Saline solution (Sterile 0.9% sodium chloride)</td><td>Hospira Inc.</td><td>NDC 0409-0138-22</td><td></td></tr><tr><td>0.9% Sodium chloride Injection</td><td>Hospira Inc.</td><td>NDC 0409-4888-10</td><td></td></tr><tr><td>Petrolatum Ophthalmic Ointment</td><td>Dechra Veterinary Products</td><td>NDC 17033-211-38</td><td></td></tr><tr><td>Iodine Prep Pads</td><td>Triad Disposables, Inc.</td><td>NDC 50730-3201-1</td><td></td></tr><tr><td>Alcohol Prep Pads</td><td>McKesson Corp.</td><td>NDC 68599-5805-1</td><td></td></tr><tr><td>Cotton tipped applicators</td><td>Fisher Sientific</td><td>23-400-118</td><td></td></tr><tr><td>Fine Scissor</td><td>FST</td><td>14028-10</td><td></td></tr><tr><td>Micro-Adson Forcep</td><td>FST</td><td>11018-12</td><td></td></tr><tr><td>Clamp Applying Forcep</td><td>FST</td><td>00072-14</td><td></td></tr><tr><td>S&amp;amp;T Vascular Clamp</td><td>FST</td><td>00396-01</td><td></td></tr><tr><td>Spring Scissors</td><td>FST</td><td>15008-08</td><td></td></tr><tr><td>Colibri Retractors</td><td>FST</td><td>17000-04</td><td></td></tr><tr><td>Dumont #5 Forcep</td><td>FST</td><td>11251-20</td><td></td></tr><tr><td>Dumont #7 - Fine Forceps</td><td>FST</td><td>11274-20</td><td></td></tr><tr><td>Dumont #5/45 Forceps</td><td>FST</td><td>11251-35</td><td></td></tr><tr><td>Tish Needle Holder/Forceps</td><td>Micrins</td><td>MI1540</td><td></td></tr><tr><td>Black Polyamide Monofilament Suture, 10-0</td><td>AROSurgical Instruments Corporation</td><td>TI638402</td><td>For sutureing the graft</td></tr><tr><td>Black Polyamide Monofilament Suture, 6-0</td><td>AROSurgical Instruments</td><td>SN-1956</td><td>For musculature and skin closure</td></tr><tr><td>Non Woven Sponges</td><td>McKesson Corp.</td><td>94442000</td><td></td></tr><tr><td>Absorbable hemostat</td><td>Ethicon</td><td>1961</td><td></td></tr><tr><td>1 ml Syringe</td><td>BD</td><td>309659</td><td></td></tr><tr><td>3 ml Syringe</td><td>BD</td><td>309657</td><td></td></tr><tr><td>10 ml Syringe</td><td>BD</td><td>309604</td><td></td></tr><tr><td>18 G 1 1/2 in, Needle</td><td>BD</td><td>305190</td><td></td></tr><tr><td>25 G 1 in., Needle</td><td>BD</td><td>305125</td><td></td></tr><tr><td>30 G 1 in., Needle</td><td>BD</td><td>305106</td><td></td></tr><tr><td>Warm Water Recircultor</td><td>Gaymar</td><td>TP-700</td><td></td></tr><tr><td>Warming Pad</td><td>Gaymar</td><td>TP-22G</td><td></td></tr><tr><td>Trimmer</td><td>Wahl</td><td>9854-500</td><td></td></tr><tr><td>VEVO2100 High Frequency Ultrasound</td><td>VisualSonics</td><td>&lt;a href=&quot;http://www.visualsonics.com/vevo2100&quot;&gt;http://www.visualsonics.com/vevo2100&lt;/a&gt;</td><td>The catalog number and pricing can be acquired from the sales representatives.</td></tr><tr><td>Ultrasound transmission gel</td><td>Parker Laboratories,&lt;br/&gt; INC.</td><td>01-02</td><td></td></tr><tr><td>Table Top Laboratory Animal Anesthesia System</td><td>VetEquip, INC.</td><td>901806</td><td></td></tr><tr><td>Isoflurane</td><td>Baxter</td><td>1001936060</td><td></td></tr></tbody></table>

transplantation of pulmonary valve using a mouse model of heterotopic heart transplantation

Tissue engineered heart valves, especially decellularized valves, are starting to gain momentum in clinical use of reconstructive surgery with mixed results. However, the cellular and molecular mechanisms of the neotissue development, valve thickening, and stenosis development are not researched extensively. To answer the above questions, we developed a murine heterotopic heart valve transplantation model. A heart valve was harvested from a valve donor mouse and transplanted to a heart donor mouse. The heart with a new valve was transplanted heterotopically to a recipient mouse. The transplanted heart showed its own heartbeat, independent of the recipient&#8217;s heartbeat. The blood flow was quantified using a high frequency ultrasound system with a pulsed wave Doppler. The flow through the implanted pulmonary valve showed forward flow with minimal regurgitation and the peak flow was close to 100 mm/sec. This murine model of heart valve transplantation is highly versatile, so it can be modified and adapted to provide different hemodynamic environments and/or can be used with various transgenic mice to study neotissue development in a tissue engineered heart valve.

Figure 1 illustrates the schematics of the heart valve transplantation model using heterotopic heart transplantation. The heart valve was harvested from a donor heart and implanted onto a heart from a second donor mouse. Then the heart with the new heart valve was implanted to the abdomen of a recipient mouse. Figure 2 shows an illustration of the implanted heart on the abdominal space (A), right after heart transplantation (B), and 5 min after transplantation. Upon removing sutures on both sides of the aorta and IVC, the heart starts to beat 1-2 min later and becomes pinker with more blood circulation. Note that the right atrium is more dilated in (C) than (B). The heart gradually beats stronger and is stable after 24 hr.
The blood flow through the implanted pulmonary valve was measured percutaneously 10 days after implantation using a high frequency ultrasound system with the pulsed-wave Doppler mode (Figure 3). The locations of the aorta, right ventricle (RV), implanted pulmonary valve (PV), and pulmonary artery (PA) in B mode was shown in Figure 3 (A). The yellow sample volume overlay is located on the implanted PV. Figure 3 (B) shows a diagram of the anatomy and the location of the sample volume overlay. As shown in Figure 3 (C), the donor heart QRS wave was detected rhythmically and independent of the recipient heart wave. The measured systolic and diastolic blood volume at the implanted PV matched the donor heart wave. The peak velocity was around 100 mm/sec.
<img alt="Figure 1" fo:content-width="5in" fo:src="/files/ftp_upload/51695/51695fig1highres.jpg" src="/files/ftp_upload/51695/51695fig1.jpg" /> 
Figure 1.&#160;Schematic of heart valve transplantation. A pulmonary heart valve was harvested from a first donor mouse and implanted into a heart from a second donor mouse. Then the heart with the new valve was implanted heterotopically into a recipient mouse.
<img alt="Figure 2" fo:content-width="5in" fo:src="/files/ftp_upload/51695/51695fig2highres.jpg" src="/files/ftp_upload/51695/51695fig2.jpg" /> 
Figure 2.&#160;The transplanted heart. A)&#160;A diagram of a heart with new heart valve implanted to abdominal space (B) right after the implantation, and (C) 5 min&#160;after implantation.
<img alt="Figure 3" fo:content-width="5in" fo:src="/files/ftp_upload/51695/51695fig3highres.jpg" src="/files/ftp_upload/51695/51695fig3.jpg" /> 
Figure 3.&#160;Blood flow measurement in implanted pulmonary valve. A)&#160;B-mode image indicating the locations of aorta, right ventricle (RV), implanted pulmonary valve (PV) and pulmonary artery (PA). B)&#160;A diagram of the anatomy and location of the sample volume overlay. C)&#160;Velocity measurement at the implanted PV with ECG wave.

Watch this Scientific Journal Video about Transplantation of Pulmonary Valve Using a Mouse Model of Heterotopic Heart Transplantation at JoVE.com

Transplantation of Pulmonary Valve Using a Mouse Model of Heterotopic Heart Transplantation

In order to understand the cellular and molecular mechanisms underlying neotissue formation and stenosis development in tissue engineered heart valves, a murine model of heterotopic heart valve transplantation was developed. A pulmonary heart valve was transplanted to recipient using the heterotopic heart transplantation technique.

Tissue engineered heart valves, especially decellularized valves, are starting to gain momentum in clinical use of reconstructive surgery with mixed ...

transplantation-pulmonary-valve-using-mouse-model-heterotopic-heart

Nanyang Technological University

Research

JoVE Journal

Medicine

18.8K Views.  Nationwide Children's Hospital.  Om de cellulaire en moleculaire mechanismen die ten grondslag liggen neotissue vorming en stenose ontwikkeling in tissue engineered hartkleppen begrijpen, een muizenmodel van heterotopische hartklep transplantatie werd ontwikkeld. Een pulmonale hartklep werd getransplanteerd naar ontvanger via de heterotopische harttransplantatie techniek. 

Video: Transplantation of Pulmonary Valve Using a Mouse Model of Heterotopic Heart Transplantation

Heterotopic Heart Transplantation in Mice

The mouse heterotopic heart transplantation has been used widely since it was introduced by Drs. Corry and Russell in 1973. It is particularly valuable for studying rejection and immune response now that newer transgenic and gene knockout mice are available, and a large number of immunologic reagents have been developed. The heart transplant model is less stringent than the skin transplant models, although technically more challenging. We have developed a modified technique and have completed over 1000 successful cases of heterotopic heart transplantation in mice. When making anastomosis of the ascending aorta and abdominal aorta, two stay sutures are placed at the proximal and distal apexes of recipient abdominal aorta with the donor s ascending aorta, then using 11-0 suture for anastomosis on both side of aorta with continuing sutures. The stay sutures make the anastomosis easier and 11-0 is an ideal suture size to avoid bleeding and thrombosis.
When making anastomosis of pulmonary artery and inferior vena cava, two stay sutures are made at the proximal apex and distal apex of the recipient s inferior vena cava with the donor s pulmonary artery. The left wall of the inferior vena cava and donor s pulmonary artery is closed with continuing sutures in the inside of the inferior vena cava after, one knot with the proximal apex stay suture the right wall of the inferior vena cava and the donor s pulmonary artery are closed with continuing sutures outside the inferior vena cave with 10-0 sutures. This method is easier to perform because anastomosis is made just on the one side of the inferior vena cava and 10-0 sutures is the right size to avoid bleeding and thrombosis. In this article, we provide details of the technique to supplement the video.

The mouse heterotopic heart transplantation model has been proven by many investigators to be an important method for studying mechanisms of rejection and immune response. However, the techniques involved are still challenging. By modifying standard techniques we have had success with more than 1000 transplants.

The mouse heterotopic heart transplantation has been used widely since it was introduced by Drs. Corry and Russell in 1973. It is particularly valuable ...

Biology

Murine Cervical Heart Transplantation Model Using a Modified Cuff Technique

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are available to perform mechanistic in vivo studies. While heart transplantation models using a suture technique were first successfully developed in rats, the translation into an equally widespread used murine equivalent was never achieved due the technical complexity of the microsurgical procedure. In contrast, non-suture cuff techniques, also developed initially in rats, were successfully adapted for use in mice1-3. This technique for revascularization involves two major steps I) everting the recipient vessel over a polyethylene cuff; II) pulling the donor vessel over the formerly everted recipient vessel and holding it in place with a circumferential tie. This ensures a continuity of the endothelial layer, short operating time and very high patency rates4.
Using this technique for vascular anastomosis we performed more than 1,000 cervical heart transplants with an overall success rate of 95%. For arterial inflow the common carotid artery and the proximal aortic arch were anastomosed resulting in a retrograde perfusion of the transplanted heart. For venous drainage the pulmonary artery of the graft was anastomosed with the external jugular vein of the recipient5.
Herein, we provide additional details of this technique to supplement the video.

The murine cervical heart transplantation model is well suited for immunological as well as ischemia reperfusion injury studies. We modified the procedure using a non-suture cuff technique and performed more than 1,000 successful transplants with this approach.
Herein, we provide additional details of this technique to supplement the video.

Mouse models are of special interest in research since a wide variety of monoclonal antibodies and commercially defined inbred and knockout strains are ...

A Modified Method for Heterotopic Mouse Heart Transplantion

Mice are often used as heart transplant donors and recipients in studies of transplant immunology due to the wide range of transgenic mice and reagents available. A difficulty is presented due to the small size of the animal and the considerable technical challenges of the microsurgery involved in heart transplantation. In particular, a high rate of technical failure early after transplantation may result from recipient death and post-operative complications such as hind limb paralysis or a non-beating heart. Here, the complete technique for heterotopic mouse heart transplantation is demonstrated, involving harvesting the donor heart and its subsequent implantation into a recipient mouse. The donor heart is harvested immediately following in situ perfusion with cold heparinized saline and transection of the ascending aorta and pulmonary artery. The recipient operation involves preparation of the abdominal aorta and inferior vena cava (IVC), followed by end-to-side anastomosis of the donor aorta with the recipient aorta using a single running 10-0 microsuture and a similar anastomosis of the donor pulmonary artery with the recipient IVC. Following the operation the animal is injected with 0.6 ml normal saline subcutaneously and allowed to recover on a 37&#160;&#176;C heating pad. The results from 227 mouse heart transplants are summarized with a success rate at 48 hr of 86.8%. Of the 13.2% failures within 48 hr, 5 (2.2%) experienced hind limb paralysis, 10 (4.4%) had a non-beating heart due to graft ischemic injury and/or thrombosis, while 15 (6.6%) died within 48 hr.

A technique is demonstrated for the microsurgical procedure for heterotopic transplantation of hearts in mice, including simplified methods for donor harvesting and recipient vessel anastomosis.

Mice are often used as heart transplant donors and recipients in studies of transplant immunology due to the wide range of transgenic mice and reagents ...

Murine Heterotopic Heart Transplant Technique

It is now over forty years since this technique was first reported by Corry, Wynn and Russell. Although it took some years for other labs to become proficient in and utilize this technique, it is now widely used by many laboratories around the world. A significant refinement to the original technique was developed and reported in 2001 by Niimi. Described here are the techniques that have evolved over more than a decade in the hands of three surgeons (Plenter, Grazia, Pietra) in our center. These techniques are now being passed on to a younger generation of surgeons and researchers.
Based largely on the Niimi experience, the procedures used have evolved in the fine details - details which we will endeavor to relate here in such a way that others may be able to use this very useful model. Like Niimi, we have found that a video aid to learning is a priceless resource for the beginner.

The manuscript describes the steps required to perform the heterotopic heart transplant in the mouse.

It is now over forty years since this technique was first reported by Corry, Wynn and Russell. Although it took some years for other labs to become ...

A Novel Microsurgical Model for Heterotopic, En Bloc Chest Wall, Thymus, and Heart Transplantation in Mice

Exploration of novel strategies in organ transplantation to prolong allograft survival and minimizing the need for long-term maintenance immunosuppression must be pursued. Employing vascularized bone marrow transplantation and co-transplantation of the thymus have shown promise in this regard in various animal models.1-11 Vascularized bone marrow transplantation allows for the uninterrupted transfer of donor bone marrow cells within the preserved donor microenvironment, and the incorporation of thymus tissue with vascularized bone marrow transplantation has shown to increase T-cell chimerism ultimately playing a supportive role in the induction of immune regulation. The combination of solid organ and vascularized composite allotransplantation can uniquely combine these strategies in the form of a novel transplant model. Murine models serve as an excellent paradigm to explore the mechanisms of acute and chronic rejection, chimerism, and tolerance induction, thus providing the foundation to propagate superior allograft survival strategies for larger animal models and future clinical application. Herein, we developed a novel heterotopic en bloc chest wall, thymus, and heart transplant model in mice using a cervical non-suture cuff technique. The experience in syngeneic and allogeneic transplant settings is described for future broader immunological investigations via an instructional manuscript and video supplement.

To study combined solid organ and vascularized composite allotransplantation, we describe a novel heterotopic en bloc chest wall, thymus, and heart transplant model in mice using a cervical non-suture cuff technique.

Exploration of novel strategies in organ transplantation to prolong allograft survival and minimizing the need for long-term maintenance immunosuppression ...

A Pre-Clinical Porcine Model of Orthotopic Heart Transplantation

Fifty-years following the first successful report, cardiac transplantation remains the gold-standard treatment for eligible patients with advanced heart failure. Multiple small-animal models of heart transplantation have been used to study the acute and long-term effects of novel therapies. However, few are tested and demonstrated success in clinical trials. It is of critical importance to evaluate new therapies in a clinically relevant large-animal model for efficient and reliable translation of basic studies&#39;&#160;findings. Here, we describe a pre-clinical large-animal (porcine) model of orthotopic heart transplantation that has been firmly established and previously used to investigate novel cardioprotective strategies. This procedure focuses on acute ischemia-reperfusion injury and is a reliable method to investigate novel interventions which have been tested and validated in smaller experimental models, such as the murine model. We demonstrate its usefulness in assessing cardiac performance during the early post-transplantation period and other potential possibilities enabled by the model.

Here, we describe a pre-clinical large-animal (porcine) model of orthotopic heart transplantation that has been firmly established and utilized to investigate novel cardioprotective strategies.

Fifty-years following the first successful report, cardiac transplantation remains the gold-standard treatment for eligible patients with advanced heart ...

Mouse Heterotopic Cervical Cardiac Transplantation Utilizing Vascular Cuffs

Murine models of cardiac transplantation are frequently utilized to study ischemia-reperfusion injury, innate and adaptive immune responses after transplantation, and the impact of immunomodulatory therapies on graft rejection. Heterotopic cervical heart transplantation in mice was first described in 1991 using sutured anastomoses and subsequently modified to include cuff techniques. This modification allowed for improved success rates, and since then, there have been multiple reports that have proposed further technical improvements. However, translation into more widespread utilization remains limited due to the technical difficulty associated with graft anastomoses, which requires precision to achieve adequate length and caliber of the cuffs to avoid vascular anastomotic twisting or excessive tension, which can result in damage to the graft. The present protocol describes a modified technique for performing heterotopic cervical cardiac transplantation in mice which involves cuff placement on the recipient's common carotid artery and the donor's pulmonary artery in alignment with the direction of the blood flow.

Mouse cardiac transplantation models represent valuable research tools for studying transplantation immunology. The present protocol details mouse heterotopic cervical cardiac transplantation that involves the placement of cuffs on the recipient's common carotid artery and the donor's pulmonary artery trunk to allow for laminar blood flow.

Murine models of cardiac transplantation are frequently utilized to study ischemia-reperfusion injury, innate and adaptive immune responses after ...

Immunology and Infection

Blood Circuit Reconstruction in an Abdominal Mouse Heart Transplantation Model

The surgical technique of heterotopic abdominal heart transplantation in mice is a standard model for research in transplantation immunology. Here, the established technique for a modified blood circuit reconstruction in a heterotopic abdominal heart transplantation model is presented. This method uses the intrathoracic inferior vena cava (IIVC) instead of the pulmonary artery of the donor heart for the anastomosis to the inferior vena cava of the recipient. It is facilitating and improving success rates for abdominal heart transplantation in mice.

A novel technique for blood circuit reconstruction in a heterotopic abdominal mouse heart transplantation model is demonstrated.

The surgical technique of heterotopic abdominal heart transplantation in mice is a standard model for research in transplantation immunology. Here, the ...

A Simplified Model for Heterotopic Heart Valve Transplantation in Rodents

There is an urgent clinical need for heart valve replacements that can grow in children. Heart valve transplantation is proposed as a new type of transplant with the potential to deliver durable heart valves capable of somatic growth with no requirement for anticoagulation. However, the immunobiology of heart valve transplants remains unexplored, highlighting the need for animal models to study this new type of transplant. Previous rat models for heterotopic aortic valve transplantation into the abdominal aorta have been described, though they are technically challenging and costly. For addressing this challenge, a renal subcapsular transplant model was developed in rodents as a practical and more straightforward method for studying heart valve transplant immunobiology. In this model, a single aortic valve leaflet is harvested and inserted into the renal subcapsular space. The kidney is easily accessible, and the transplanted tissue is securely contained in a subcapsular space that is well vascularized and can accommodate a variety of tissue sizes. Furthermore, because a single rat can provide three donor aortic leaflets and a single kidney can provide multiple sites for transplanted tissue, fewer rats are required for a given study. Here, the transplantation technique is described, providing a significant step forward in studying the transplant immunology of heart valve transplantation.

This protocol describes a simple and efficient method for the transplantation of aortic valve leaflets under the renal capsule to allow for the study of alloreactivity of heart valves.

There is an urgent clinical need for heart valve replacements that can grow in children. Heart valve transplantation is proposed as a new type of ...

A Modified Cuff Technique for Mouse Cervical Heterotopic Heart Transplantation Model

Cardiac allograft rejection limits the long-term survival of patients after heart transplantation. A mouse heart transplantation model is ideal for investigating the mechanism of cardiac allograft rejection in preclinical studies because of their high homology with human genes. This understanding would help develop unique approaches to improving patients&#39; long-term survival treated with cardiac allografts. In a mouse model, abdominal donor heart implantation is commonly performed with an end-to-end&#160;anastomosis to the recipient&#39;s aorta and inferior vena cava using stitches. In this model, the donor&#39;s heart is implanted by end-to-end anastomosis to the recipient&#39;s carotid artery and jugular vein by the modified-Cuff technique. The transplantation surgery is performed without stitching and thus may increase the survival of the recipient since there is no interference with the blood supply and venous reflux of the lower body. This mouse model would help investigate the mechanisms underlying the immunological and pathological (acute/chronic) rejection of cardiac allografts.

In the present protocol, a mouse heart transplantation model is used for investigating the mechanism of cardiac allograft rejection. In this heterotopic heart transplantation model, operation efficiency is improved, and the survival of cardiac grafts is ensured by a cervical end-to-end anastomosis of heart implantation using a modified Cuff technique.

Cardiac allograft rejection limits the long-term survival of patients after heart transplantation. A mouse heart transplantation model is ideal for ...

Transplantation of Pulmonary Valve Using a Mouse Model of Heterotopic Heart Transplantation

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