Name: decellularization of whole human heart inside a pressurized pouch in an inverted orientation
Uploaded: 2018-11-26T13:30:00
Description: Watch this Scientific Journal Video about Decellularization of Whole Human Heart Inside a Pressurized Pouch in an Inverted Orientation at JoVE.com

This research was supported by the Houston Endowment grant and the Texas Emerging Technology Fund. The authors acknowledge the organ procurement agency LifeGift, Inc. and the donor&#39;s families for making this study possible.

All experiments adhered to the ethics committee guidelines from the Texas Heart Institute.
1. Organ Preparation
NOTE: In collaboration with LifeGift, a nonprofit organ procurement organization in Texas (http://www.lifegift.org), donated human hearts not suitable for transplant were used for research with approved consent.
<ol>
	<li>To procure hearts, intravenously infuse 30,000 U heparin to the hearts. Securely suture cardioplegia cannula in the aorta and attach a...

<ol>
	<li>Writing Group Members. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Executive+Summary:+Heart+Disease+and+Stroke+Statistics--2016+Update:+A+Report+From+the+American+Heart+Association.">Executive Summary: Heart Disease and Stroke Statistics--2016 Update: A Report From the American Heart Association.</a> Circulation. 133 (4), 447-454 (2016).</li><li>Zia, 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=Hearts+beating+through+decellularized+scaffolds:+whole-organ+engineering+for+cardiac+regeneration+and+transplantation.">Hearts beating through decellularized scaffolds: whole-organ engineering for cardiac regeneration and transplantation.</a> Critical Reviews in Biotechnology. 36 (4), 705-715 (2016).</li><li>Zimmermann, W. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strip+and+Dress+the+Human+Heart.">Strip and Dress the Human Heart.</a> Circulation Research. 118 (1), 12-13 (2016).</li><li>Ott, H. C., 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=Perfusion-decellularized+matrix:+Using+nature's+platform+to+engineer+a+bioartificial+heart.">Perfusion-decellularized matrix: Using nature's platform to engineer a bioartificial heart.</a> Nature Medicine. 14 (2), 213-221 (2008).</li><li>Sanchez, P. L., 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=Acellular+human+heart+matrix:+A+critical+step+toward+whole+heart+grafts.">Acellular human heart matrix: A critical step toward whole heart grafts.</a> Biomaterials. 61, 279-289 (2015).</li><li>Peloso, 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=Current+achievements+and+future+perspectives+in+whole-organ+bioengineering.">Current achievements and future perspectives in whole-organ bioengineering.</a> Stem Cell Research &amp; Therapy. 6, 107 (2015).</li><li>Guyette, J. P., 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=Perfusion+decellularization+of+whole+organs.">Perfusion decellularization of whole organs.</a> Nature Protocols. 9 (6), 1451-1468 (2014).</li><li>Momtahan, N., Sukavaneshvar, S., Roeder, B. L., Cook, A. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strategies+and+Processes+to+Decellularize+and+Cellularize+Hearts+to+Generate+Functional+Organs+and+Reduce+the+Risk+of+Thrombosis.">Strategies and Processes to Decellularize and Cellularize Hearts to Generate Functional Organs and Reduce the Risk of Thrombosis.</a> Tissue Engineering Part B-Reviews. 21 (1), 115-132 (2015).</li><li>Lee, P. F., 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=Inverted+orientation+improves+decellularization+of+whole+porcine+hearts.">Inverted orientation improves decellularization of whole porcine hearts.</a> Acta Biomaterialia. , (2016).</li><li>Momtahan, 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=Automation+of+Pressure+Control+Improves+Whole+Porcine+Heart+Decellularization.">Automation of Pressure Control Improves Whole Porcine Heart Decellularization.</a> Tissue Eng Part C Methods. , (2015).</li><li>Weymann, 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=Development+and+Evaluation+of+a+Perfusion+Decellularization+Porcine+Heart+Model+-+Generation+of+3-Dimensional+Myocardial+Neoscaffolds.">Development and Evaluation of a Perfusion Decellularization Porcine Heart Model - Generation of 3-Dimensional Myocardial Neoscaffolds.</a> Circulation Journal. 75 (4), 852-860 (2011).</li><li>Weymann, 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=Bioartificial+heart:+A+human-sized+porcine+model--the+way+ahead.">Bioartificial heart: A human-sized porcine model--the way ahead.</a> PLoS One. 9 (11), e111591 (2014).</li><li>Remlinger, N. T., Wearden, P. D., Gilbert, T. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Procedure+for+decellularization+of+porcine+heart+by+retrograde+coronary+perfusion.">Procedure for decellularization of porcine heart by retrograde coronary perfusion.</a> Journal of Visualized Experiments. (70), e50059 (2012).</li><li>Guyette, J. P., 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=Bioengineering+Human+Myocardium+on+Native+Extracellular+Matrix.">Bioengineering Human Myocardium on Native Extracellular Matrix.</a> Circulation Research. 118 (1), 56-72 (2016).</li><li>Sanchez, P. L., 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=Data+from+acellular+human+heart+matrix.">Data from acellular human heart matrix.</a> Data Brief. 8, 211-219 (2016).</li><li>Garreta, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myocardial+commitment+from+human+pluripotent+stem+cells:+Rapid+production+of+human+heart+grafts.">Myocardial commitment from human pluripotent stem cells: Rapid production of human heart grafts.</a> Biomaterials. 98, 64-78 (2016).</li><li>Wainwright, J. 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=Preparation+of+Cardiac+Extracellular+Matrix+from+an+Intact+Porcine+Heart.">Preparation of Cardiac Extracellular Matrix from an Intact Porcine Heart.</a> Tissue Engineering Part C-Methods. 16 (3), 525-532 (2010).</li><li>Larson, A. M., Yeh, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ex+vivo+characterization+of+sub-10-fs+pulses.">Ex vivo characterization of sub-10-fs pulses.</a> Optics Letters. 31 (11), 1681-1683 (2006).</li><li>Lee, P. F., Yeh, A. T., Bayless, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nonlinear+optical+microscopy+reveals+invading+endothelial+cells+anisotropically+alter+three-dimensional+collagen+matrices.">Nonlinear optical microscopy reveals invading endothelial cells anisotropically alter three-dimensional collagen matrices.</a> Experimental Cell Research. 315 (3), 396-410 (2009).</li><li>Lee, P. F., Bai, Y., Smith, R. L., Bayless, K. J., Yeh, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Angiogenic+responses+are+enhanced+in+mechanically+and+microscopically+characterized,+microbial+transglutaminase+crosslinked+collagen+matrices+with+increased+stiffness.">Angiogenic responses are enhanced in mechanically and microscopically characterized, microbial transglutaminase crosslinked collagen matrices with increased stiffness.</a> Acta Biomaterialia. 9 (7), 7178-7190 (2013).</li><li>Wu, Z., 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=Multi-photon+microscopy+in+cardiovascular+research.">Multi-photon microscopy in cardiovascular research.</a> Methods. 130, 79-89 (2017).</li><li>Ramanathan, T., Skinner, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coronary+blood+flow.">Coronary blood flow.</a> Continuing Education in Anaesthesia Critical Care &amp; Pain. 5 (2), 61-64 (2005).</li><li>Murthy, V. L., 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=Clinical+Quantification+of+Myocardial+Blood+Flow+Using+PET:+Joint+Position+Paper+of+the+SNMMI+Cardiovascular+Council+and+the+ASNC.">Clinical Quantification of Myocardial Blood Flow Using PET: Joint Position Paper of the SNMMI Cardiovascular Council and the ASNC.</a> Journal of Nuclear Cardiology. 25 (1), 269-297 (2018).</li><li>Molina, D. K., DiMaio, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normal+organ+weights+in+men:+Part+I-the+heart.">Normal organ weights in men: Part I-the heart.</a> The American Journal of Forensic Medicine and Pathology. 33 (4), 362-367 (2012).</li><li>Molina, D. K., DiMaio, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Normal+Organ+Weights+in+Women:+Part+I-The+Heart.">Normal Organ Weights in Women: Part I-The Heart.</a> The American Journal of Forensic Medicine and Pathology. 36 (3), 176-181 (2015).</li><li>Robertson, M. J., Dries-Devlin, J. L., Kren, S. M., Burchfield, J. S., Taylor, 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=Optimizing+cellularization+of+whole+decellularized+heart+extracellular+matrix.">Optimizing cellularization of whole decellularized heart extracellular matrix.</a> PLoS One. 9 (2), e90406 (2014).</li><li>Robertson, M. J., Soibam, B., O'Leary, J. G., Sampaio, L. C., Taylor, 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=Cellularization+of+rat+liver:+An+in+vitro+model+for+assessing+human+drug+metabolism+and+liver+biology.">Cellularization of rat liver: An in vitro model for assessing human drug metabolism and liver biology.</a> PLoS One. 13 (1), e0191892 (2018).</li><li>Baghalishahi, 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=Cardiac+extracellular+matrix+hydrogel+together+with+or+without+inducer+cocktail+improves+human+adipose+tissue-derived+stem+cells+differentiation+into+cardiomyocyte-like+cells.">Cardiac extracellular matrix hydrogel together with or without inducer cocktail improves human adipose tissue-derived stem cells differentiation into cardiomyocyte-like cells.</a> Biochemical and Biophysical Research Communications. , (2018).</li><li>Perea-Gil, 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=In+vitro+comparative+study+of+two+decellularization+protocols+in+search+of+an+optimal+myocardial+scaffold+for+recellularization.">In vitro comparative study of two decellularization protocols in search of an optimal myocardial scaffold for recellularization.</a> American Journal of Translational Research. 7 (3), 558-573 (2015).</li><li>Freytes, D. O., O'Neill, J. D., Duan-Arnold, Y., Wrona, E. A., Vunjak-Novakovic, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+cardiac+extracellular+matrix+hydrogels+for+cultivation+of+human+stem+cell-derived+cardiomyocytes.">Natural cardiac extracellular matrix hydrogels for cultivation of human stem cell-derived cardiomyocytes.</a> Methods Molecular Biology. 1181, 69-81 (2014).</li><li>Oberwallner, B., 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=Preparation+of+cardiac+extracellular+matrix+scaffolds+by+decellularization+of+human+myocardium.">Preparation of cardiac extracellular matrix scaffolds by decellularization of human myocardium.</a> Journal of Biomedical Materials Research Part A. 102 (9), 3263-3272 (2014).</li></ol>

To our knowledge, this is the first study to report inverted decellularization of human hearts inside a pressurized pouch with time-lapse monitoring of flow rate and cell debris removal. The pericardium-like pouch keeps the orientation of the heart stable throughout the decellularization procedure. Submerging and inverting the whole hearts inside a pouch prevents dehydration and minimizes excessive strain on the aorta (from heart weight) when compared to the conventional upright Langendorff perfusion decellularization me...

Heart failure leads to high mortality in patients. The ultimate treatment option for end-stage heart failure is allo-transplantation. However, there is a long wait-list for transplantation due to the shortage of donor organs, and patients face post-transplantation hurdles that range from life-long immunosuppression to chronic organ rejection1,2. Bioengineering functional hearts by repopulating decellularized human-sized hearts with a patient&#39;s own cells could circumvent these hurdles3.
A major step in &#34;engineering&#34; a heart is the creation of a scaffold with appropriate vascular and parenchymal structure, composition and function to guide the alignment and organization of delivered cells. In the presence of the appropriate framework, cells seeded on the scaffold should recognize the environment and perform the expected function as part of that organ. In our opinion, decellularized organ extracellular matrix (dECM) comprises the necessary characteristics of the ideal scaffold.
By utilizing intrinsic vasculature, complex whole-organ decellularization can be achieved via antegrade or retrograde perfusion4 to remove cellular components while preserving the delicate 3D extracellular matrix and vasculature2,5,6,7. A functional vasculature is important in bioengineering whole organs just as it is in vivo, for nutrient distribution and waste removal8. Coronary perfusion decellularization has been proven to be effective in creating decellularized hearts from rats4, or pigs4,7,9,10,11,12,13, and humans5,7,14,15,16. Yet, integrity of the valves, atria and other &#34;thin&#34; regions can suffer.
Human-size decellularized heart scaffolds can be obtained from pigs using pressure control7,9,10,11,12 or infusion flow rate control13,17 and from human donors using pressure control5,7,14,15. Decellularization of human donor hearts occurs over 4-8 days under pressure controlled at 80-100 mmHg in upright orientation5,15,16 or over 16 days under pressure controlled at 60 mmHg14. Under antegrade, pressure-controlled decellularization, the aortic valve competency plays a crucial role in maintaining coronary perfusion efficiency and stable pressure at the aortic root. Our previous work revealed that the orientation of the heart influences its coronary perfusion efficiency during the decellularization procedure and therefore the scaffold integrity in the end9.
As a continuation of our previous work9, we introduce a novel concept wherein a pericardium-like pouch is added to improve whole-heart decellularization. We describe the decellularization of human hearts placed inside pressurized pouches, inversely oriented, and under pressure controlled at 120 mmHg at the aortic root. This protocol includes monitoring the flow profile and collection of outflow media throughout the decellularization procedure to evaluate coronary perfusion efficiency and cell debris removal. Biochemical assays are then performed to test the effectiveness of the method.

<table>
	<tbody>
		<tr>
			<td>2-0 silk suture</td>
			<td>Ethicon</td>
			<td>SA85H</td>
			<td>Suture used to ligate superior and inferior vena cava</td>
		</tr>
		<tr>
			<td>1/4&#34; x 3/8&#34; connector with luer</td>
			<td>NovoSci</td>
			<td>332023-000</td>
			<td>Connect aorta and pulmonary artery</td>
		</tr>
		<tr>
			<td>Masterflex platinum-cured silicone tubing</td>
			<td>Cole-Parmer</td>
			<td>HV-96410-16</td>
			<td>Tubing to connect heart chambers/veins</td>
		</tr>
		<tr>
			<td>infusion and outflow line</td>
			<td>Smiths Medical</td>
			<td>MX452FL</td>
			<td>For flowing solutions through the vasculature</td>
		</tr>
		<tr>
			<td>Polyester pouch (Ampak 400 Series SealPAK Pouches)</td>
			<td>Fisher scientific</td>
			<td>01-812-17</td>
			<td>Pericardium-like pouch for containing heart during decellularization</td>
		</tr>
		<tr>
			<td>Snapware Square-Grip Canister</td>
			<td>Snapware</td>
			<td>1022</td>
			<td>1-liter Container used for perfusing heart</td>
		</tr>
		<tr>
			<td>Black rubber stoppers</td>
			<td>VWR</td>
			<td>59586-162</td>
			<td>To seal the perfusion container</td>
		</tr>
		<tr>
			<td>Peristaltic pump</td>
			<td>Harvard Apparatus</td>
			<td>881003</td>
			<td>To pump fluid through the inflow lines and to drain fluids</td>
		</tr>
		<tr>
			<td>2 L aspirator bottle with bottom sidearm</td>
			<td>VWR</td>
			<td>89001-532</td>
			<td>For holding solutions/perfusate</td>
		</tr>
		<tr>
			<td>Quant-iT PicoGreen dsDNA Assay kit</td>
			<td>Life Technologies</td>
			<td>P7589</td>
			<td>For quantifying dsDNA</td>
		</tr>
		<tr>
			<td>Calf thymus standard</td>
			<td>Sigma</td>
			<td>D4522</td>
			<td>DNA standard</td>
		</tr>
		<tr>
			<td>Blyscan Glycosaminoglycan Assay Kit</td>
			<td>Biocolor Ltd</td>
			<td>Blyscan #B1000</td>
			<td>GAG assay kit</td>
		</tr>
		<tr>
			<td>Plate reader</td>
			<td>Tecan</td>
			<td>Infinite M200 Pro</td>
			<td>For analytical assays</td>
		</tr>
		<tr>
			<td>GE fluoroscopy</td>
			<td>General Electric</td>
			<td>OEC 9900 Elite</td>
			<td>Angiogram</td>
		</tr>
		<tr>
			<td>Visipaque</td>
			<td>GE</td>
			<td>13233575</td>
			<td>Contrast agent</td>
		</tr>
	</tbody>
</table>

decellularization of whole human heart inside a pressurized pouch in an inverted orientation

The ultimate solution for patients with end-stage heart failure is organ transplant. But donor hearts are limited, immunosuppression is required, and ultimately rejection can occur. Creating a functional, autologous bio-artificial heart could solve these challenges. Biofabrication of a heart comprised of scaffold and cells is one option. A natural scaffold with tissue-specific composition as well as micro- and macro-architecture can be obtained by decellularizing hearts from humans or large animals such as pigs. Decellularization involves washing out cellular debris while preserving 3D extracellular matrix and vasculature and allowing &#34;cellularization&#34; at a later timepoint. Capitalizing on our novel finding that perfusion decellularization of complex organs is possible, we developed a more &#34;physiological&#34; method to decellularize non-transplantable human hearts by placing them inside a pressurized pouch, in an inverted orientation, under controlled pressure. The purpose of using a pressurized pouch is to create pressure gradients across the aortic valve to keep it closed and improve myocardial perfusion. Simultaneous assessment of flow dynamics and cellular debris removal during decellularization allowed us to monitor both fluid inflow and debris outflow, thereby generating a scaffold that can be used either for simple cardiac repair (e.g. as a patch or valve scaffold) or as a whole-organ scaffold.

After a 7-day decellularization with antegrade aortic perfusion under constant pressure of 120 mmHg, the human heart turned translucent (Figure 6B). The heart was grossly dissected into 19 sections for biochemical (DNA, GAG and SDS) analysis (Figure 6C) to evaluate the final decellularized product.
Throughout the decellularization process, infusion flow rate of differen...

Watch this Scientific Journal Video about Decellularization of Whole Human Heart Inside a Pressurized Pouch in an Inverted Orientation at JoVE.com

Decellularization of Whole Human Heart Inside a Pressurized Pouch in an Inverted Orientation

This method enables decellularization of a complex solid organ using a simple protocol based on osmotic shock and perfusion of ionic detergent with minimal organ matrix disruption. It comprises a novel decellularization technique for human hearts inside a pressurized pouch with real-time monitoring of flow dynamics and cellular debris outflow.

The ultimate solution for patients with end-stage heart failure is organ transplant. But donor hearts are limited, immunosuppression is required, and ...

This method can help answer key questions about generating vascularized scaffolds, which are really the Holy Grail of the tissue engineering field. The main advantage of this technique is that a pressurized pouch in an inverted orientation improves the decellularization of non-transplantable human organs and lets us do that in a sterile fashion over an appropriate time frame. To prepare the heart for decellularization, first perform an internal inspection for possible defects.If a septal defect is present, correct the defect with the appropriate sutures. Next, ligate the superior and inferior vena cavas with 2-0 silk suture. Suture the right atrium wall with 5-0 PROLENE, and dissect the aorta away from the main pulmonary artery for subsequent cannulation.Insert the connectors, according to the diameter of the vessel, into the aorta and the pulmonary artery, and secure the connectors with 2-0 silk sutures. Using one of the pulmonary vein orifices, insert a tubing line through the left atrium toward the left ventricle, and connect an infusion line to the connector in the aorta and an outflow line to the connector in the pulmonary artery. Place the prepared heart into a polyester pouch in the inverted orientation, and place the pouch into a perfusion container.Connect each of the lines to the respective ports in the rubber stopper, according to the diameter of container, and insert the stopper into the lid of the perfusion container to seal the polyester pouch. Then, perfuse PBS via the infusion port of the rubber stopper to verify the outflow from the pulmonary artery and from the line inserted into the left ventricle, using this flow to clean the organ of any residual traces of blood within the vasculature. When the heart is ready, place the assembled bioreactor in an upright orientation, and connect the infusion line, pressure-head line, pulmonary artery-outflow line, and bioreactor draining line to the rubber cap surface ports on top of the perfusion bioreactor.Then, decellularize the heart for four hours with hypertonic solution, two hours with hypotonic solution, 120 hours with sodium dodecyl sulfate, or SDS, and a final wash with 120 liters of PBS, all under constant 120 millimeters of mercury pressure as measured at the aortic root. During the last 10 liters of the PBS wash, add 500 milliliters of sterile 2.1%peracetic acid solution neutralized with 10 normal sodium hydroxide to the perfusion solution to sterilize the scaffold. Typically, the flow rate into the aorta during the decellularization process gradually decreases as the perfusion solution changes from hypertonic to hypotonic.In contrast, the flow rate increases when the perfusion solution is changed from a hypotonic solution to SDS, at which point the infusion flow rate demonstrates fluctuations. The outflow rate from the pulmonary artery demonstrates a similar trend with the hyper-and hypotonic solutions. However, the outflow rate during the SDS perfusion exhibits an overall decrease.The coronary perfusion efficiency also decreases over time as the different reagents are perfused through the vasculature. As the outflow perfusate from the pulmonary artery and left ventricle are simultaneously collected, their debris content can be compared by spectroscopy. The turbidity of the effluent from both the vessels decreases over time during the perfusions, although the turbidity from the pulmonary artery exhibits a more abrupt color change compared to that observed from the left ventricle during the initial perfusion period.Evaluation of the correlation between the outflow turbidity and the cell debris by a bicinchoninic acid protein assay from six decellularized human hearts reveals a linear correlation between the protein concentration and the effluent turbidity. While attempting this procedure, it's important to monitor the flow rate and to collect the perfusate periodically to actually monitor the perfusion process. Following this procedure, other techniques like mechanical evaluation or sterility testing can be used to evaluate the fidelity of the scaffold and its potential use for recellularization to generate a functional cardiac tissue.After its development, this technique paved the way for researchers in the regenerative medicine and tissue engineering field to explore the generation of whole vascularized organs, literally changing the solid organ transplant field. Don't forget that working with human organs and tissues and chemicals such as SDS can be extremely hazardous, and always wear appropriate personal protection equipment when undertaking this procedure.

decellularization-whole-human-heart-inside-pressurized-pouch-an

Research

JoVE Journal

Bioengineering

Decellularization and Recellularization of Whole Livers

The liver is a complex organ which requires constant perfusion for delivery of nutrients and oxygen and removal of waste in order to survive1. Efforts to recreate or mimic the liver microstructure with grounds up approach using tissue engineering and microfabrication techniques have not been successful so far due to this design challenge. In addition, synthetic biomaterials used to create scaffolds for liver tissue engineering applications have been limited in inducing tissue regeneration and repair in large part due to the lack of specific cell binding motifs that would induce the proper cell functions2. Decellularized native tissues such blood vessels3and skin4on the other hand have found many applications in tissue engineering, and have provided a practical solution to some of the challenges. The advantage of decellularized native matrix is that it retains, to an extent, the original composition, and the microstructure, hence enhancing cell attachment and reorganization5.
In this work we describe the methods to perform perfusion-decellularization of the liver, such that an intact liver bioscaffold that retains the structure of major blood vessels is obtained. Further, we describe methods to recellularize these bioscaffolds with adult primary hepatocytes, creating a liver graft that is functional in vitro, and has the vessel access necessary for transplantation in vivo.

Perfusion decellularization is a novel technique to produce whole liver scaffolds that retains the organ's extracellular matrix composition and microarchitecture. Herein, the method of preparing whole organ scaffolds using perfusion decellularization and subsequent repopulation with hepatocytes is described. Functional and transplantable liver grafts can be generated using this technique.

The liver is a complex organ which requires constant perfusion for delivery of nutrients and oxygen and removal of waste in order to survive1. Efforts to ...

Multiparametric Optical Mapping of the Langendorff-perfused Rabbit Heart

Optical imaging and fluorescent probes have significantly advanced research methodology in the field of cardiac electrophysiology in ways that could not have been accomplished by other approaches1. With the use of the calcium- and voltage-sensitive dyes, optical mapping allows measurement of transmembrane action potentials and calcium transients with high spatial resolution without the physical contact with the tissue. This makes measurements of the cardiac electrical activity possible under many conditions where the use of electrodes is inconvenient or impossible1. For example, optical recordings provide accurate morphological changes of membrane potential during and immediately after stimulation and defibrillation, while conventional electrode techniques suffer from stimulus-induced artifacts during and after stimuli due to electrode polarization1. 
The Langendorff-perfused rabbit heart is one of the most studied models of human heart physiology and pathophysiology. Many types of arrhythmias observed clinically could be recapitulated in the rabbit heart model. It was shown that wave patterns in the rabbit heart during ventricular arrhythmias, determined by effective size of the heart and the wavelength of reentry, are very similar to that in the human heart2. It was also shown that critical aspects of excitation-contraction (EC) coupling in rabbit myocardium, such as the relative contribution of sarcoplasmic reticulum (SR), is very similar to human EC coupling3. Here we present the basic procedures of optical mapping experiments in Langendorff-perfused rabbit hearts, including the Langendorff perfusion system setup, the optical mapping systems setup, the isolation and cannulation of the heart, perfusion and dye-staining of the heart, excitation-contraction uncoupling, and collection of optical signals. These methods could be also applied to the heart from species other than rabbit with adjustments to flow rates, optics, solutions, etc.
Two optical mapping systems are described. The panoramic mapping system is used to map the entire epicardium of the rabbit heart4-7. This system provides a global view of the evolution of reentrant circuits during arrhythmogenesis and defibrillation, and has been used to study the mechanisms of arrhythmias and antiarrhythmia therapy8,9. The dual mapping system is used to map the action potential (AP) and calcium transient (CaT) simultaneously from the same field of view10-13. This approach has enhanced our understanding of the important role of calcium in the electrical alternans and the induction of arrhythmia14-16.

This article describes the basic procedures for conducting optical mapping experiments in the Langendorff-perfused rabbit heart using the panoramic imaging system, and the dual (voltage and calcium) imaging modality.

Optical imaging and fluorescent probes have significantly advanced research methodology in the field of cardiac electrophysiology in ways that could not ...

Procedure for Decellularization of Porcine Heart by Retrograde Coronary Perfusion

Perfusion-based whole organ decellularization has recently gained interest in the field of tissue engineering as a means to create site-specific extracellular matrix scaffolds, while largely preserving the native architecture of the scaffold. To date, this approach has been utilized in a variety of organ systems, including the heart, lung, and liver 1-5. Previous decellularization methods for tissues without an easily accessible vascular network have relied upon prolonged exposure of tissue to solutions of detergents, acids, or enzymatic treatments as a means to remove the cellular and nuclear components from the surrounding extracellular environment6-8. However, the effectiveness of these methods hinged upon the ability of the solutions to permeate the tissue via diffusion. In contrast, perfusion of organs through the natural vascular system effectively reduced the diffusion distance and facilitated transport of decellularization agents into the tissue and cellular components out of the tissue. Herein, we describe a method to fully decellularize an intact porcine heart through coronary retrograde perfusion. The protocol yielded a fully decellularized cardiac extracellular matrix (c-ECM) scaffold with the three-dimensional structure of the heart intact. Our method used a series of enzymes, detergents, and acids coupled with hypertonic and hypotonic rinses to aid in the lysis and removal of cells. The protocol used a Trypsin solution to detach cells from the matrix followed by Triton X-100 and sodium deoxycholate solutions to aid in removal of cellular material. The described protocol also uses perfusion speeds of greater than 2 L/min for extended periods of time. The high flow rate, coupled with solution changes allowed transport of agents to the tissue without contamination of cellular debris and ensured effective rinsing of the tissue. The described method removed all nuclear material from native porcine cardiac tissue, creating a site-specific cardiac ECM scaffold that can be used for a variety of applications.

A method to rapidly and completely remove cellular components from an intact porcine heart through retrograde perfusion is described. This method yields a site specific cardiac extracellular matrix scaffold which has the potential for use in multiple clinical applications.

Perfusion-based  whole organ decellularization has recently gained interest in the field of  tissue engineering as a means to create site-specific ...

A Decellularization Methodology for the Production of a Natural Acellular Intestinal Matrix

Successful tissue engineering involves the combination of scaffolds with appropriate cells in vitro or in vivo. Scaffolds may be synthetic, naturally-derived or derived from tissues/organs. The latter are obtained using a technique called decellularization. Decellularization may involve a combination of physical, chemical, and enzymatic methods. The goal of this technique is to remove all cellular traces whilst maintaining the macro- and micro-architecture of the original tissue.
Intestinal tissue engineering has thus far used relatively simple scaffolds that do not replicate the complex architecture of the native organ. The focus of this paper is to describe an efficient decellularization technique for rat small intestine. The isolation of the small intestine so as to ensure the maintenance of a vascular connection is described. The combination of chemical and enzymatic solutions to remove the cells whilst preserving the villus-crypt axis in the luminal aspect of the scaffold is also set out. Finally, assessment of produced scaffolds for appropriate characteristics is discussed.

The article describes a methodology for the production of an acellular matrix from rat intestine. The derivation of intestinal scaffolds is important for future applications in tissue engineering, stem cell biology and drug testing.

Successful tissue engineering involves the  combination of scaffolds with appropriate cells in vitro or in vivo.  Scaffolds may be synthetic, ...

An Injectable and Drug-loaded Supramolecular Hydrogel for Local Catheter Injection into the Pig Heart

Regeneration of lost myocardium is an important goal for future therapies because of the increasing occurrence of chronic ischemic heart failure and the limited access to donor hearts. An example of a treatment to recover the function of the heart consists of the local delivery of drugs and bioactives from a hydrogel. In this paper a method is introduced to formulate and inject a drug-loaded hydrogel non-invasively and side-specific into the pig heart using a long, flexible catheter. The use of 3-D electromechanical mapping and injection via a catheter allows side-specific treatment of the myocardium. To provide a hydrogel compatible with this catheter, a supramolecular hydrogel is used because of the convenient switching from a gel to a solution state using environmental triggers. At basic pH this ureido-pyrimidinone modified poly(ethylene glycol) acts as a Newtonian fluid which can be easily injected, but at physiological pH the solution rapidly switches into a gel. These mild switching conditions allow for the incorporation of bioactive drugs and bioactive species, such as growth factors and exosomes as we present here in both in vitro and in vivo experiments. The in vitro experiments give an on forehand indication of the gel stability and drug release, which allows for tuning of the gel and release properties before the subsequent application in vivo. This combination allows for the optimal tuning of the gel to the used bioactive compounds and species, and the injection system.

Supramolecular hydrogelators based on ureido-pyrimidinones allow full control over the macroscopic gel properties and the sol&#8211;gel switching behavior using pH. Here, we present a protocol for formulating and injecting such a supramolecular hydrogelator via a catheter delivery system for local delivery directly in relevant areas in the pig heart.

Regeneration of lost myocardium is an important goal for future therapies because of the increasing occurrence of chronic ischemic heart failure and the ...

Procedure for Decellularization of Rat Livers in an Oscillating-pressure Perfusion Device

Decellularization and recellularization of parenchymal organs may enable the generation of functional organs in vitro, and several protocols for rodent liver decellularization have already been published. We aimed to improve the decellularization process by construction of a proprietary perfusion device enabling selective perfusion via the portal vein and/or the hepatic artery. Furthermore, we sought to perform perfusion under oscillating surrounding pressure conditions to improve the homogeneity of decellularization. The homogeneity of perfusion decellularization has been an underestimated factor to date. During decellularization, areas within the organ that are poorly perfused may still contain cells, whereas the extracellular matrix (ECM) in well-perfused areas may already be affected by alkaline detergents. Oscillating pressure changes can mimic the intraabdominal pressure changes that occur during respiration to optimize microperfusion inside the liver. In the study presented here, decellularized rat liver matrices were analyzed by histological staining, DNA content analysis and corrosion casting. Perfusion via the hepatic artery showed more homogenous results than portal venous perfusion did. The application of oscillating pressure conditions improved the effectiveness of perfusion decellularization. Livers perfused via the hepatic artery and under oscillating pressure conditions showed the best results. The presented techniques for liver harvesting, cannulation and perfusion using our proprietary device enable sophisticated perfusion set-ups to improve decellularization and recellularization experiments in rat livers.

The presented techniques for liver harvesting, cannulation and perfusion using our proprietary device enable sophisticated perfusion set-ups to improve decellularization and recellularization experiments in rat livers.

Decellularization and recellularization of parenchymal organs may enable the generation of functional organs in vitro, and several protocols for rodent ...

Decellularization and Recellularization Methodology for Human Saphenous Veins

Vascular conduits used during most vascular surgeries are allogeneic or synthetic grafts that often lead to complications caused by immunosuppression and poor patency. Tissue engineering offers a novel solution to generate personalized grafts with a natural extracellular matrix containing the recipient&#39;s cells using the method of decellularization and recellularization. We show a detailed method for performing decellularization of the human saphenous vein and recellularization by perfusion of peripheral blood. The vein was decellularized by perfusing 1% Triton X-100, 1% tri-n-butyl-phosphate (TnBP) and 2,000 Kunitz units of deoxyribonuclease (DNase). Triton X-100 and TnBP were perfused at 35 mL/min for 4 h while DNase was perfused at 10 mL/min at 37 &#176;C for 4 h. The vein was washed in ultrapure water and PBS and then sterilized in 0.1% peracetic acid. It was washed again in PBS and preconditioned in endothelial medium. The vein was connected to a bioreactor and perfused with endothelial medium containing 50 IU/mL heparin for 1 h. Recellularization was performed by filling the bioreactor with fresh blood, diluted 1:1 in Steen solution, and adding endocrine gland-derived vascular endothelial growth factors (80 ng/mL), basic fibroblast growth factors (4 &#181;L/mL), and acetyl salicylic acid (5 &#181;g/mL). The bioreactor was then moved into an incubator and perfused for 48 h at 2 mL/min while maintaining glucose between 3 - 9 mmol/L. Later, the vein was washed with PBS, filled with endothelial medium and perfused for 96 h in the incubator. Treatment with Triton X-100, TnBP and DNase decellularized the saphenous vein in 5 cycles. The decellularized vein looked white in contrast to normal and recellularized veins (light red). The hematoxylin &#38; eosin (H&#38;E) staining showed the presence of nuclei only in normal but not in decellularized veins. In the recellularized vein, H&#38;E-staining showed the presence of cells on the luminal surface of the vein.

Here, we describe a protocol for the saphenous vein decellularization using detergents and recellularization by perfusion of the peripheral blood and the endothelial medium.

Vascular conduits used during most vascular surgeries are allogeneic or synthetic grafts that often lead to complications caused by immunosuppression and ...

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

Organ engineering is a novel strategy to generate liver organ substitutes that can potentially be used in transplantation. Recently, in vivo liver engineering, including in vivo organ decellularization followed by repopulation, has emerged as a promising approach over ex vivo liver engineering. However, postoperative survival was not achieved. The aim of this study is to develop a novel surgical technique of in vivo selective liver lobe perfusion in rats as a prerequisite for in vivo liver engineering. We generate a circuit bypass only through the left lateral lobe. Then, the left lateral lobe is perfused with heparinized saline. The experiment is performed with 4 groups (n = 3 rats per group) based on different perfusion times of 20 min, 2 h, 3 h, and 4 h. Survival, as well as the macroscopically visible change of color and the histologically determined absence of blood cells in the portal triad and the sinusoids, is taken as an indicator for a successful model establishment. After selective perfusion of the left lateral lobe, we observe that the left lateral lobe, indeed, turned from red to faint yellow. In a histological assessment, no blood cells are visible in the branch of the portal vein, the central vein, and the sinusoids. The left lateral lobe turns red after reopening the blocked vessels. 12/12 rats survived the procedure for more than one week. We are the first to report a surgical model for in vivo single liver lobe perfusion with a long survival period of more than one week. In contrast to the previously published report, the most important advantage of the technique presented here is that perfusion of 70% of the liver is maintained throughout the whole procedure. The establishment of this technique provides a foundation for in vivo partial liver engineering in rats, including decellularization and recellularization.

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

We establish a novel surgical technique for an in vivo single liver lobe perfusion model in rat as a prerequisite for further studying in vivo partial liver engineering in the future.

Organ engineering is a novel strategy to generate liver organ substitutes that can potentially be used in transplantation. Recently, in vivo liver ...

Isolation and Decellularization of a Whole Porcine Pancreas

Tissue engineering of the whole pancreas can improve current treatments for diabetes mellitus. The ultimate goal is to tissue engineer pancreas from an allogeneic or xenogeneic source with human cells. A demonstration of methods for the efficient dissection, decellularization, and recellularization of porcine pancreas might benefit the field. Akin to human pancreases, porcine pancreases have a special anatomical arrangement with three lobes (splenic, duodenal, and connection) rounded by the duodenum and small intestine. The duodenal lobe of the pancreas connects to the duodenum by several small blood vessels. Tissue engineering of the pancreas is complicated because of its exocrine and endocrine nature. In this paper, we show a detailed protocol to dissect the whole porcine pancreas and decellularize it with detergents while saving its structure and some extracellular matrix components. To achieve complete perfusion, the aorta is chosen as inlet and the portal vein as outlet. The other blood vessels (hepatic artery, splenic vein, splenic artery,&#160;mesenteric artery and vein tree) and bile duct are ligated. To prevent the formation of thrombus, the pig is heparinized and, immediately after dissection, the organ is flushed with cold heparin. To inhibit the action of exocrine enzymes, the pancreas decellularization is set at 4 &#176;C. The decellularization is performed by perfusion of Triton X-100, sodium deoxycholate, and deoxyribonuclease, with an intermittent and final extensive washing. With a successful decellularization, the pancreas appears white, and a histological evaluation with hematoxylin and eosin shows an absence of nuclei with a preserved extracellular matrix structure. Thus, the proposed method can be used to successfully dissect and decellularize whole porcine pancreas.

Tissue engineering of the whole pancreas is a challenge because of its exocrine and endocrine functions. We show a method for the dissection of an intact porcine pancreas and the process of successful decellularization by perfusion of detergents Triton X-100, sodium deoxycholate, and deoxyribonuclease.

Tissue engineering of the whole pancreas can improve current treatments for diabetes mellitus. The ultimate goal is to tissue engineer pancreas from an ...

Cardiac Spheroids as in vitro Bioengineered Heart Tissues to Study Human Heart Pathophysiology

Despite several advances in cardiac tissue engineering, one of the major challenges to overcome remains the generation of a fully functional vascular network comprising several levels of complexity to provide oxygen and nutrients within bioengineered heart tissues. Our laboratory has developed a three-dimensional in vitro model of the human heart, known as the "cardiac spheroid" or "CS". This presents biochemical, physiological, and pharmacological features typical of the human heart and is generated by co-culturing its three major cell types, such as cardiac myocytes, endothelial cells, and fibroblasts. Human induced pluripotent stem cells-derived cardiomyocytes (hiPSC-CMs or iCMs) are co-cultured at ratios approximating the ones found in vivo with human cardiac fibroblasts (HCFs) and human coronary artery endothelial cells (HCAECs) in hanging drop culture plates for three to four days. The confocal analysis of CSs stained with antibodies against cardiac Troponin T, CD31 and vimentin (markers for cardiac myocytes, endothelial cells and fibroblasts, respectively) shows that CSs present a complex endothelial cell network, resembling the native one found in the human heart. This is confirmed by the 3D rendering analysis of these confocal images. CSs also present extracellular matrix (ECM) proteins typical of the human heart, such as collagen type IV, laminin and fibronectin. Finally, CSs present a contractile activity measured as syncytial contractility closer to the one typical of the human heart compared to CSs that contain iCMs only. When treated with a cardiotoxic anti-cancer agent, such as doxorubicin (DOX, used to treat leukemia, lymphoma and breast cancer), the viability of DOX-treated CSs is significantly reduced at 10 &#181;M genetic and chemical inhibition of endothelial nitric oxide synthase, a downstream target of DOX in HCFs and HCAECs, reduced its toxicity in CSs. Given these unique features, CSs are currently used as in vitro models to study heart biochemistry, pathophysiology, and pharmacology.

This protocol aims to fabricate 3D cardiac spheroids (CSs) by co-culturing cells in hanging drops.&#160;Collagen-embedded CSs are treated with doxorubicin (DOX, a cardiotoxic agent) at physiological concentrations to model heart failure. In vitro testing using DOX-treated CSs may be used to identify novel therapies for heart failure patients.

Despite several advances in cardiac tissue engineering, one of the major challenges to overcome remains the generation of a fully functional vascular ...