Os autores gostariam de agradecer Brogan Visitante, Michelle Weaver e Kristen Lippert. O financiamento para este estudo foi fornecido pelo NIH Grant R03EB009237, bem como bolsas de formação NIH T32EB001026-06 do Instituto Nacional de Imagem Biomédica e Bioengenharia e T32HL076124-05.

1. Preparação de tecidos e Experimento Setup <ol><li> Colheita de órgãos suínos imediatamente após a eutanásia de um abatedouro ou de pesquisa e enxaguar o excesso de sangue. Aparar o coração do excesso de gordura e de tecido, mantendo os átrios e aorta intacta. Aparar a gordura para separar a artéria pulmonar da aorta. Se houver quaisquer cortes no tecido, descartar adequadamente. </li><li> Enrole cada coração individualmente em papel freezer e armazenar todo o tecido em um congelador -80 ° C durante pelo menos 24 horas para garantir a congelação completa. </li><li> Quando pronto para uso (geralmente menos do que 3 meses), descongelar um coração porcino intacto congelado em água do tipo 1 durante a noite submersa num copo de L 4 a 4 ° C. </li><li> Depois que o coração está completamente descongelado, pat o coração seco, pesar no coração, e registrar o peso. O coração de um porco peso de mercado deve pesar cerca de 375-450 g. </li><li> Ligue tamanho 18 tubulação Masterflex a ¼ final &quot;de um redutor de farpado. Insira o redutor farpado etubo no interior da aorta. Braçadeiras de mangueira coloque 2 ou laços zip seguras ao redor da aorta, logo abaixo do tronco braquiocefálico. O redutor e tubo deve permanecer acima da válvula da aorta, para as artérias coronárias podem ser perfundidos (Figura 1). </li><li> Use uma seringa de 30 ou 60 ml para encher o tubo com água Tipo I. Inserir o tubo no interior do cartucho de uma bomba Masterflex rolo no seu ponto médio aproximado. Submerge final do fluxo de entrada da tubagem no fundo de um copo de L 4 preenchido com 2,5 L de água e fixar o tubo. </li><li> Colocar o coração no copo cheio de água, e a bomba principal para remover bolhas de ar. Se forem observadas bolhas provenientes da aorta onde o tubo é inserido, a aorta pode precisar de ser reposicionada ou protegido com laços adicionais. Uma vedação estanque ao ar é importante para manter a pressão adequada durante o processo de descelularização (Figura 2). </li><li> Colocar o copo L 4 contendo 3 L de uma 0,2% NaN Trypsin/0.05% EDTA/0.05%3 Solução de agitar placa e aquecê-la a 37 ° C em preparação para o processo de descelulação. </li></ol> 2. Lava tecido <ol><li> Definir a bomba a uma taxa de fluxo de 400 ml / min, assegurando que a dimensão da mangueira correcto está seleccionado. Lave o coração com água tipo I para 15-25 min. Como a bomba é iniciado, o coração deve inchar e derramar o sangue dos ventrículos. Solução fresca deve ser substituído a cada 5-10 minutos, ou conforme necessário, com base na quantidade de sangue removido a partir do coração. Se o sangue não é emanada a partir do coração, ajustar o tubo e as braçadeiras conforme necessário. </li><li> Parar a bomba e transferir o coração para uma proveta separada cheio com Solução Salina Tamponada com Fosfato 2X (PBS). Depois o tubo é imerso em solução, o arranque da bomba e aumentar a taxa de fluxo de 700 ml / min. O coração deve permanecer em solução durante 15 minutos, a mudança da solução a cada 5 min. Cada alteração solução requer que a bomba seja interrompido temporariamente, enquanto o tecido e tubo é movidopara o copo de novo. </li><li> Transferir o coração ao Tipo I de água durante 10 minutos e aumentar a taxa de fluxo de 750 ml / min. </li></ol> 3. Perfusão decelularização e solução <ol><li> Transferir o coração ao copo contendo 0,2% Trypsin/0.05% EDTA/0.05% NaN3 a 37 ° C. Aumentar a velocidade da bomba de 1200 ml / min e ligar a bomba. Use uma barra de agitação colocados na parte inferior do copo para fazer circular solução no copo. O coração deve permanecer na Trypsin/0.05% EDTA/0.05% 0,2% NaN3 solução a 37 ° C durante um total de três horas. Depois de 1 hora, aumentar a velocidade da bomba de 1500 ml / min. Depois de uma hora adicional, aumentar a velocidade da bomba de 1800 ml / min. O tecido é sujeito a lentamente velocidades de perfusão aumentado para condicionar os tecidos e prevenir a ruptura dos vasos. O coração vai inchar e quase o dobro em tamanho durante esta etapa do protocolo. O tecido vai perder a sua cor natural, progredindo a partir do átrio para o ápice durante todo diae protocolo (Figura 3). </li><li> Depois de cada solução de perfusão, de um de dois passos lavagem é realizada para remover os restos celulares, resíduos químicos, e a lise das células de ajuda. Cada lavagem é constituída por uma lavagem de 10 min em água de Tipo I, seguido por uma lavagem de 10 min com 2X solução de PBS à temperatura ambiente. Cada lavagem consiste na remoção da solução a partir do recipiente original, a adição de soluções de lavagem, e fazer circular o perfusato no copo contendo o coração submerso. Após a 0,2% Trypsin/0.05% EDTA/0.05% NaN3 solução de água, perfundir a 1.900 ml / min e, em seguida, perfundir 2X PBS a 1950 ml / min. </li><li> Transferir o coração para uma solução de 3% de Triton% X-100/0.05 EDTA/0.05% NaN3 à temperatura ambiente. Aumentar a velocidade da bomba de 2000 ml / min e uma solução de perfundir durante uma hora. Remover a solução a partir do recipiente e substituir com solução fresca, aumentar a velocidade da bomba a 2100 ml / min, e perfundir a solução fresca durante mais uma hora e meia, trazendo o tempo total em3% de Triton X-100/0.05% EDTA/0.05% NaN 3-2,5 h. </li><li> Enxaguar o tecido em água do tipo I em 2150 ml / min e em PBS 2x 2180 ml / min, durante 10 min cada. </li><li> Transferir o coração para uma solução de desoxicolato de sódio a 4%, à temperatura ambiente. Aumentar a velocidade da bomba de 2200 ml / min e uma solução de perfundir durante 3 hr. </li><li> Enxaguar o tecido em água e de tipo I em 2X PBS a 2200 ml / min durante 15 minutos cada, depois de alterar as soluções de 5-10 min para cada solução. Os passos descritos de perfusão pode ser dividida em vários dias por realizar a etapa de lavagem duas vezes e armazenando o coração com tubagem ligado durante a noite a 4 ° C e submersos em água do tipo I. </li><li> No dia seguinte, executar a 5 minutos, lavar com água de Tipo I, a 750 ml / min, seguida por uma lavagem de 5 minutos em PBS 1X a 1,500 ml / min. O protocolo pode então ser continuada a uma taxa de fluxo descrito na solução apropriada. </li></ol> 4. Desinfecção e Processamento Final <ol><li> Transferir o coração a uma perac 0,1%ácido etic / solução de etanol a 4% e solução perfundir durante 1,5 horas a 2200 ml / min. </li><li> As enxaguaduras finais para o tecido são todos realizados a 2.200 ml / min. Perfundir o tecido com 1X PBS durante 15 min, seguido por duas lavagens de 5 min em água de tipo I. Esta série de lavagens é repetido mais uma vez, a fim de completar o procedimento de perfusão de solução. </li><li> Desligar a bomba e retirar o coração da solução para drenar o coração. Cortar os laços da aorta, remover todos os tubos, e colocar o coração em um copo vazio para drenar durante 1 h. O excesso de líquido terá de ser drenado periodicamente. Deite o coração de uma almofada absorvente para drenar completamente o coração (Figura 4). </li><li> Depois de a maior parte da água é removida, registrar o peso da matriz extracelular cardíaca (C-ECM). O coração pode ser esperado para perder cerca de 20-25% do seu peso inicial, durante o processo de descelulação. </li><li> Dissecar os ventrículos direito e esquerdo, bem como do septo ventricular para DNA quantificatie no processamento histológico, a fim de confirmar a descelularização completa do tecido (Figura 5). </li><li> Congele o C-ECM a -80 ° C durante pelo menos 2 horas antes da liofilização. </li></ol>

<ol>
	<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=Regeneration+and+orthotopic+transplantation+of+a+bioartificial+lung.">Regeneration and orthotopic transplantation of a bioartificial lung.</a> Nat. Med. 16, 927-933 (2010).</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> Nat. Med. , (2008).</li><li>Petersen, T. H., 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+lungs+for+in+vivo+implantation.">Tissue-engineered lungs for in vivo implantation.</a> Science. 329, 538-541 (2010).</li><li>Uygun, B. 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=Organ+reengineering+through+development+of+a+transplantable+recellularized+liver+graft+using+decellularized+liver+matrix.">Organ reengineering through development of a transplantable recellularized liver graft using decellularized liver matrix.</a> Nat. Med. , (2010).</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 Eng. Part C Methods. 16, 525-532 (2010).</li><li>Crapo, P. M., Gilbert, T. W., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+overview+of+tissue+and+whole+organ+decellularization+processes.">An overview of tissue and whole organ decellularization processes.</a> Biomaterials. 32, 3233-3243 (2011).</li><li>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=Strategies+for+tissue+and+organ+decellularization.">Strategies for tissue and organ decellularization.</a> Journal of cellular biochemistry. , (2012).</li><li>Gilbert, T. W., Sellaro, T. L., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decellularization+of+tissues+and+organs.">Decellularization of tissues and organs.</a> Biomaterials. 27, 3675-3683 (2006).</li><li>Akhyari, 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=The+quest+for+an+optimized+protocol+for+whole-heart+decellularization:+a+comparison+of+three+popular+and+a+novel+decellularization+technique+and+their+diverse+effects+on+crucial+extracellular+matrix+qualities.">The quest for an optimized protocol for whole-heart decellularization: a comparison of three popular and a novel decellularization technique and their diverse effects on crucial extracellular matrix qualities.</a> Tissue Eng. Part C Methods. 17, 915-926 (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=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 : official journal of the Japanese Circulation Society. 75, 852-860 (2011).</li><li>Cortiella, J., 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=Influence+of+acellular+natural+lung+matrix+on+murine+embryonic+stem+cell+differentiation+and+tissue+formation.">Influence of acellular natural lung matrix on murine embryonic stem cell differentiation and tissue formation.</a> Tissue Eng. Part A. 16, 2565-2580 (1089).</li><li>Remlinger, N. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrated+xenogeneic+decellularized+tracheal+matrix+as+a+scaffold+for+tracheal+reconstruction.">Hydrated xenogeneic decellularized tracheal matrix as a scaffold for tracheal reconstruction.</a> Biomaterials. 31, 3520-3526 (2010).</li><li>Sellaro, T. L., Ravindra, A. K., Stolz, D. B., Badylak, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maintenance+of+hepatic+sinusoidal+endothelial+cell+phenotype+in+vitro+using+organ-specific+extracellular+matrix+scaffolds.">Maintenance of hepatic sinusoidal endothelial cell phenotype in vitro using organ-specific extracellular matrix scaffolds.</a> Tissue Eng. 13, 2301-2310 (2007).</li><li>Wainwright, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Right+ventricular+outflow+tract+repair+with+a+cardiac+biologic+scaffold.">Right ventricular outflow tract repair with a cardiac biologic scaffold.</a> Cells, tissues, organs. 195, 159-170 (2012).</li></ol>

Dr. Gilbert estava no Conselho Consultivo Científico em ACell, Inc. enquanto o estudo estava sendo feito, e, recentemente, tornou-se o vice-presidente de Pesquisa e Desenvolvimento. ACell, Inc. vende matriz bexiga urinária e não tem interesse comercial no presente estudo.

O presente estudo descreve a metodologia para a descelularização consistente e eficaz de um coração porcino. O protocolo foi uma modificação de um relatório publicado anteriormente 1, e inclui uma exposição mais longa ao fluxo e pressão elevada, o que proporcionou resultados mais reprodutíveis. O tecido resultante descelularizado atendeu a todos os critérios publicados para a descelularização sucesso de tecido 2. Solução muda frequentes foram realizadas para limitar a reintrodução...

<table border="1"><tbody><tr><td> Nome do reagente / Material </td><td> Companhia </td><td> Número de Catálogo </td><td> Comentários </td></tr><tr><td> Tripsina </td><td> Gibco </td><td> 15090 </td><td></td></tr><tr><td> EDTA </td><td> Pescador </td><td> BP120-500 </td><td></td></tr><tr><td> NaN3 </td><td> Sigma </td><td> S2002-500G </td><td></td></tr><tr><td> Triton X-100 </td><td> Sigma </td><td> X100-1L </td><td></td></tr><tr><td> PBS 10X </td><td> Pescador </td><td> BP399-20 </td><td></td></tr><tr><td> Deoxicolato de sódio </td><td> Sigma </td><td> D6750-500G </td><td></td></tr><tr><td> Ácido Peracético </td><td> Pfaltz e Bauer </td><td> P05020 </td><td> 35% CAS # 79-21-0 </td></tr><tr><td> Etanol </td><td> Pharmco </td><td> 111000200 </td><td></td&gt; </tr><tr><td> Masterflex bomba de acionamento </td><td> Cole Parmer </td><td> SI-07524-50 </td><td></td></tr><tr><td> Tubulação Masterflex </td><td> Cole Parmer </td><td> 96400-18 </td><td> Tamanho 18 </td></tr><tr><td> Redutor farpado </td><td> Cole Parmer </td><td> EW-30612-20 </td><td></td></tr><tr><td> Beaker 4L </td><td> Fisher Scientific </td><td> 02-540T </td><td></td></tr></tbody></table>

procedure for decellularization of porcine heart by retrograde coronary perfusion

Perfusão baseado descelularização órgão inteiro recentemente ganhou interesse no campo da engenharia de tecidos, como um meio de criar locais específicos andaimes de matriz extracelular, enquanto que em grande parte preservando a arquitectura nativa do andaime. Até à data, esta abordagem tem sido utilizada para uma variedade de sistemas de órgãos, incluindo o coração, pulmão, fígado e 1-5. Métodos anteriores para a descelularização de tecidos, sem uma rede de fácil acesso vascular têm contado após a exposição prolongada do tecido a soluções de detergentes, ácidos, ou tratamentos enzimáticos, como um meio para remover os componentes celulares e nucleares a partir do ambiente circundante extracelular 6-8. No entanto, a eficácia destes métodos articulada sobre a capacidade das soluções para permear o tecido por meio de difusão. Em contraste, a perfusão de órgãos por meio do sistema natural vascular reduzido eficazmente a distância de difusão e transporte facilitado de decellularizatiem agentes para o tecido e os componentes celulares para fora do tecido. Aqui, nós descrevemos um método para a plena decellularize um coração suíno intacta através de perfusão coronariana retrógrada. O protocolo produziu uma totalmente descelularizado cardíaca matriz extracelular (ECM-c) de andaime com a estrutura tridimensional do coração intacto. O nosso método de uso de uma série de enzimas, ácidos e detergentes, juntamente com enxaguamentos hipertónicas e hipotónico para ajudar na remoção e lise de células. O protocolo utilizado uma solução de Tripsina a separar as células da matriz seguido de soluções de Triton X-100 e desoxicolato de sódio para ajudar na remoção do material celular. O protocolo descrito também utiliza velocidades de perfusão superiores a 2 L / min, por períodos de tempo prolongados. A taxa de fluxo elevada, juntamente com a solução muda de agentes de transporte autorizados para o tecido, sem contaminação de detritos celulares e eficaz assegurada a lavagem do tecido. O método descrito removido todo o material nuclear da native tecido cardíaco porcino, criando um local específico cardíaco ECM andaime que pode ser utilizado para uma variedade de aplicações.

O efeito da descelularização sobre corações porcinos inteiros naturalmente varia devido a diferenças no tamanho, pressões e arranjo do vaso. Portanto, a composição exacta dos derivados scaffolds da matriz extracelular não será o mesmo de coração para coração. A realização do protocolo descrito produzirá um coração que parece branca ou translúcida, o que indica a perda de material celular. No entanto, é geralmente aceite que um tecido, pode ser considerado como &quot;descelularizado&quot; com base na...

Watch this Scientific Journal Video about Procedure for Decellularization of Porcine Heart by Retrograde Coronary Perfusion at JoVE.com

Procedure for Decellularization of Porcine Heart by Retrograde Coronary Perfusion

Um método para rápida e completamente remover componentes celulares a partir de um coração porcino intacta através da perfusão retrógrada é descrito. Este método produz um sítio específico cardíaco matriz extracelular andaime que tem o potencial para uso em várias aplicações clínicas.

Procedimento para decelularização do Coração Suínos por perfusão coronariana retrógrada

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

procedure-for-decellularization-porcine-heart-retrograde-coronary

Research

JoVE Journal

Bioengineering

23.7K visualizações.  McGowan Institute for Regenerative Medicine. Um método para rápida e completamente remover componentes celulares a partir de um coração porcino intacta através da perfusão retrógrada é descrito. Este método produz um sítio específico cardíaco matriz extracelular andaime que tem o potencial para uso em várias aplicações clínicas.

Vídeo: Procedure for Decellularization of Porcine Heart by Retrograde Coronary Perfusion

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.

Decelularização e Recellularization de Fígados inteiros

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 ...

Bioengenharia

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.

Procedimento para Decelularização de fígados de rato em uma Perfusão dispositivo oscilante pressão

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

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.

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.

Decellularization do coração humana dentro de uma bolsa pressurizada em uma orientação invertida

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

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.

Isolamento e Decellularization de um pâncreas todo porcino

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

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate (LAL) Assays

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause inflammation, fever, hypo- or hypertension, and, in extreme cases, can lead to tissue and organ damage that may become fatal. The amounts of endotoxin in pharmaceutical products, therefore, are strictly regulated. Among the methods available for endotoxin detection and quantification, the Limulus Amoebocyte Lysate (LAL) assay is commonly used worldwide. While any pharmaceutical product can interfere with the LAL assay, nano-formulations represent a particular challenge due to their complexity. The purpose of this paper is to provide a practical guide to researchers inexperienced in estimating endotoxins in engineered nanomaterials and nanoparticle-formulated drugs. Herein, practical recommendations for performing three LAL formats including turbidity, chromogenic and gel-clot assays are discussed. These assays can be used to determine endotoxin contamination in nanotechnology-based drug products, vaccines, and adjuvants.

Detection of Endotoxin in Nano-formulations Using Limulus Amoebocyte Lysate LAL Assays

Detection of endotoxins in engineered nanomaterials represents one of the grand challenges in the field of nanomedicine. Here, we present a case study that describes the framework composed of three different LAL formats to estimate potential endotoxin contamination in nanoparticles.

Deteção da endotoxina em Nano-formulações usando Limulus Amoebocyte Lysate (LAL) ensaios

When present in pharmaceutical products, a Gram-negative bacterial cell wall component endotoxin (often also called lipopolysaccharide) can cause ...

Time-Resolved In Vivo Measurement of Neuropeptide Dynamics by Capacitive Immunoprobe in Porcine Heart

The ability to measure biomarkers in vivo relevant to the assessment of disease progression is of great interest to the scientific and medical communities. The resolution of results obtained from current methods of measuring certain biomarkers can take several days or weeks to obtain, as they can be limited in resolution both spatially and temporally (e.g., fluid compartment microdialysis of interstitial fluid analyzed by enzyme-linked immunosorbent assay [ELISA], high-performance liquid chromatography [HPLC], or mass spectrometry); thus, their guidance of timely diagnosis and treatment is disrupted. In the present study, a unique technique for detecting and measuring peptide transmitters in vivo through the use of a capacitive immunoprobe biosensor (CI probe) is reported. The fabrication protocol and in vitro characterization of these probes are described. Measurements of sympathetic stimulation-evoked neuropeptide Y (NPY) release in vivo are provided. NPY release is correlated to the sympathetic release of norepinephrine for reference. The data demonstrate an approach for the fast and localized measurement of neuropeptides in vivo. Future applications include intraoperative real-time assessment of disease progression and minimally invasive catheter-based deployment of these probes.

Time-Resolved In Vivo Measurement of Neuropeptide Dynamics by Capacitive Immunoprobe in Porcine Heart

Established immunochemical methods to measure peptide transmitters in vivo rely on microdialysis or bulk fluid draw to obtain the sample for offline analysis. However, these suffer from spatiotemporal limitations. The present protocol describes the fabrication and application of a capacitive immunoprobe biosensor that overcomes the limitations of the existing techniques.

Medição in vivo de neuropeptídeos por imunoprobe capacitivo no coração suíno

The ability to measure biomarkers in vivo relevant to the assessment of disease progression is of great interest to the scientific and medical ...

Procurement and Perfusion-Decellularization of Porcine Vascularized Flaps in a Customized Perfusion Bioreactor

Large volume soft tissue defects lead to functional deficits and can greatly impact the patient&#39;s quality of life. Although surgical reconstruction can be performed using autologous free flap transfer or vascularized composite allotransplantation (VCA), such methods also have disadvantages. Issues such as donor site morbidity and tissue availability limit autologous free flap transfer, while immunosuppression is a significant limitation of VCA. Engineered tissues in reconstructive surgery using decellularization/recellularization methods represent a possible solution. Decellularized tissues are generated using methods that remove native cellular material while preserving the underlying extracellular matrix (ECM) microarchitecture. These acellular scaffolds can then be subsequently recellularized with recipient-specific cells.
This protocol details the procurement and decellularization methods used to achieve acellular scaffolds in a pig model. In addition, it also provides a description of the perfusion bioreactor design and setup. The flaps include the porcine omentum, tensor fascia lata, and the radial forearm. Decellularization is performed via ex vivo perfusion of low concentration sodium dodecyl sulfate (SDS) detergent followed by DNase enzyme treatment and peracetic acid sterilization in a customized perfusion bioreactor.
Successful tissue decellularization is characterized by a white-opaque appearance of flaps macroscopically. Acellular flaps show the absence of nuclei on histological staining and a significant reduction in DNA content. This protocol can be used efficiently to generate decellularized soft tissue scaffolds with preserved ECM and vascular microarchitecture. Such scaffolds can be used in subsequent recellularization studies and have the potential for clinical translation in reconstructive surgery.

The protocol describes the surgical procurement and subsequent decellularization of vascularized porcine flaps by the perfusion of sodium dodecyl sulfate detergent through the flap vasculature in a customized perfusion bioreactor.

Aquisição e Perfusão-Descelularização de Flaps Vascularizados Suínos em Biorreator de Perfusão Customizado

Large volume soft tissue defects lead to functional deficits and can greatly impact the patient&#39;s quality of life. Although surgical reconstruction ...

Procurement and Decellularization of Rat Hindlimbs Using an Ex Vivo Perfusion-Based Bioreactor for Vascularized Composite Allotransplantation

Patients with severe traumatic injuries and tissue loss require complex surgical reconstruction. Vascularized composite allotransplantation (VCA) is an evolving reconstructive avenue for transferring multiple tissues as a composite subunit. Despite the promising nature of VCA, the long-term immunosuppressive requirements are a significant limitation due to the increased risk of malignancies, end-organ toxicity, and opportunistic infections. Tissue engineering of acellular composite scaffolds is a potential alternative in reducing the need for immunosuppression. Herein, the procurement of a rat hindlimb and its subsequent decellularization using sodium dodecyl sulfate (SDS) is described. The procurement strategy presented is based upon the common femoral artery. A machine perfusion-based bioreactor system was constructed and used for ex vivo decellularization of the hindlimb. Successful perfusion decellularization was performed, resulting in a white translucent-like appearance of the hindlimb. An intact, perfusable, vascular network throughout the hindlimb was observed. Histological analyses showed the removal of nuclear contents and the preservation of tissue architecture across all tissue compartments.

Procurement and Decellularization of Rat Hindlimbs Using an Ex Vivo Perfusion-Based Bioreactor for Vascularized Composite Allotransplantation

We describe the surgical technique and decellularization process for composite rat hindlimbs. Decellularization is conducted using low-concentration sodium dodecyl sulfate through an ex vivo machine perfusion system.

Captação e Descelularização de Membros Posteriores de Rato Usando Biorreator Ex Vivo à Base de Perfusão para Alotransplante Composto Vascularizado

Patients with severe traumatic injuries and tissue loss require complex surgical reconstruction. Vascularized composite allotransplantation (VCA) is an ...

Avaliação das propriedades hidrodinâmicas em valvas aórticas suínas montadas

An Ex Vivo Porcine Model for Hydrodynamic Testing of Experimental Aortic Valve Procedures and Novel Medical Devices

The options for testing new cardiac procedures and investigative medical devices prior to use in an animal model are limited. In this study, we present a method for mounting a porcine aortic valve in a pulse duplicator to evaluate its hydrodynamic properties. These properties can then be evaluated before and after the procedure under investigation is performed and/or the investigative medical device is applied. Securing the inflow segment presents some difficulty owing to the lack of circumferential myocardium in the left ventricular outflow tract. This method addresses that issue by securing the inflow segment using the anterior leaflet of the mitral valve and then suturing the left ventricular free wall around the inflow fixture. The outflow segment is secured simply by inserting the fixture into an incision in the superior aspect of the aortic arch. We found that specimens had significantly different hydrodynamic properties before and after tissue fixation. This finding induced us to use fresh specimens in our testing and should be considered when using this method. In our work, we used this method to test novel intracardiac patch materials for use in the valvular position by performing an aortic valve neocuspidization procedure (Ozaki procedure) on the mounted porcine aortic valves. These valves were tested before and after the procedure to assess the change in hydrodynamic properties in comparison to the native valve. Herein, we report a platform for hydrodynamic testing of experimental aortic valve procedures that enables comparison with the native valve and between different devices and techniques used for the procedure under investigation.

Autor em destaque: Avançando nos testes de procedimentos cardíacos antes de embarcar em estudos com animais de grande porte 

We present a method for mounting a porcine aortic valve on a pulse duplicator to test its hydrodynamic properties. This method can be used to determine the change in hydrodynamics after the application of an experimental procedure or novel medical device prior to use in a large animal model.

Um Modelo Ex Vivo Porcino para Testes Hidrodinâmicos de Procedimentos Experimentais de Valva Aórtica e Novos Dispositivos Médicos

The options for testing new cardiac procedures and investigative medical devices prior to use in an animal model are limited. In this study, we present a ...