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. 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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. 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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.

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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

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 ...

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 ...