The authors would like to gratefully thank Steffen Lippert, Khalid Aliyev, Korinna J&#246;hrens and Katharina Struecker for their help during this project.

Los animales se mantuvieron en el Centro de Medicina Experimental (FEM, Charité, Berlín, Alemania), y todos los protocolos experimentales fueron revisados ​​y aprobados por la Oficina Estatal de Sanidad y Locales (LAGeSo, Berlín, Alemania; Reg. No. O 0365 / 11). Cosecha 1. Hígado <ol><li> Preparación prequirúrgica <ol><li> Utilice una placa de corcho para la fijación. Ponga un paño médica en el plato. Utilizando cuatro agujas, fijar una máscara de inhalación en la placa de corcho para la narcosis por inhalación intraoperatoria. </li></ol></li><li> Predisposición del Portal venosa cánula <ol><li> Conecte un catéter venoso periférico (G 20) a una llave de tres vías. El catéter venoso debe ser cortado oblicuamente, con una longitud de aprox. 1,5 cm. </li><li> De-aire del sistema usando una jeringa de 10 ml llena con solución Ringer. Es muy importante cuidadosamente-air de embolia de gas porque puede afectar negativamente a la descelularización perfusión. </li></ol></li><li> Predisposiciónde la cánula arterial <ol><li> Utilice una cánula de mariposa y cortar la aguja a una longitud de 5 mm. Colocar un tubo de 5 cm (ID 0,58 mm; OD 0.96 mm) a la aguja 5 mm y fijarlo con pegamento. Inserte un tubo de 2 cm de largo (ID 0,28 mm; OD 0.61 mm) en el tubo más grande y fijarlo con pegamento. </li><li> Slip otro tubo sobre esta construcción como tope y fijarlo con pegamento. De-aire de la cánula arterial con una jeringa de 5 ml llena con solución Ringer. </li></ol></li><li> Anestesia y Analgesia <ol><li> Inducir narcosis de la rata en la cámara de inducción de la anestesia por 3,5% de isoflurano en oxígeno a una velocidad de flujo de 1,5 L / min. </li><li> Para asegurar la analgesia segura durante la operación, inyecte metamizol (100 mg de masa corporal / kg) y dosis bajas de ketamina / medetomidina (10 mg / 0,1 mg por kg de masa corporal) por vía intraperitoneal. </li><li> Suministro de 1,5% de isoflurano en 1 L / min de oxígeno a través de la máscara de inhalación para su posterior mantenimiento de la anestesia quirúrgica. </li></ol></li><li> Arreglos preoperatorias &lt;ol&gt; <li> Afeitarse el abdomen liberalmente con una máquina de corte eléctrico. Humedecer el sitio de la incisión en el abdomen afeitado con etanol al 70% para la desinfección. </li><li> Colocar el animal en posición supina en el plato preparado, inserte la cabeza en la máscara de inhalación y fijar las extremidades con cinta y los pines médica. Retire el exceso de etanol y la piel con una compresa de gasa. </li></ol></li><li> Evaluación Anestesia <ol><li> Evaluar la profundidad de anestesia viendo la frecuencia respiratoria. Cuando la anestesia parece bastante profunda (40 a 60 respiraciones / min), comprobar si la analgesia es suficiente por tratar de desencadenar el reflejo pizca dedo utilizando pinzas quirúrgicas para pellizcar la piel entre los dedos de ambas extremidades posteriores. </li></ol></li><li> Enfoque abdominal <ol><li> Haga una incisión mediana en la pared abdominal caudal por encima de la vejiga. Cortar en este punto a los dos arcos costales laterales en forma en forma de V. Tenga cuidado de no cortar el diafragma. Tire de la pared abdominal cortar sobre el pecho. </li&gt; <li> Fijar el xifoides con una pinza Overholt, tire de él craneal y fijarlo con una banda elástica. Use hisopos de algodón mojado para evacuar el intestino. Envuelva el intestino en un vendaje de gasa húmeda. Por otra parte, cubrir todos los márgenes abdominales con vendajes húmedos. </li></ol></li><li> Preparación de hígado <ol><li> Diseccionar el ligamento falciforme. Use un vendaje de gasa húmeda para mantener los lóbulos hepáticos medial y craneal izquierda bajo la cúpula del diafragma. Exponer el ligamento hepatoduodenal y el lóbulo del hígado omental superior. </li><li> Utilice dos microforceps y tijeras de primavera para diseccionar cuidadosamente el ligamento unido al lóbulo omental superior hasta el lóbulo es móvil. Mueva el lóbulo usando hisopos de algodón mojado bajo la compresa de gasa, la celebración de los lóbulos medial y dejados en su lugar. </li><li> Después de la movilización del lóbulo hepático omental superior, mueva el estómago a la izquierda. Fijar el estómago con una pinza y diseccionar el epiplón menor con microforceps y las tijeras de primavera. </li><li> Movilizar el omentos menorl lóbulo hepático hasta que es móvil y posteriormente mover el lóbulo de nuevo en su cavidad. Utilice una abrazadera Backhaus para retener el duodeno. Mueva el duodeno a la izquierda para estirar y exponer el ligamento hepatoduodenal. Circunscribir el conducto biliar común en el ligamento hepatoduodenal estirada. </li><li> Diseccionar el conducto de la bilis desde el tejido adiposo y páncreas. Cortar el conducto biliar 1,5 cm de la bifurcación de la vía biliar. Diseccionar la vena portal desde el tejido adiposo circundante. Exponer la vena gastroduodenal. </li><li> Ligar la vena gastroduodenal dos veces con seda 6-0 y dividir la vena entre las 2 ligaduras. Diseccionar el tronco celíaco y la arteria hepática común del tejido circundante hasta que toda ramas arteriales se revelan. </li><li> Libera la arteria gastroduodenal del tejido circundante. Ate la arteria gastroduodenal dos veces con seda 6-0, con los lazos distantes unos de otros. Diseccionar la arteria gastroduodenal entre las 2 ligaduras. </li><li> Libera la arteria esplénicadel tejido circundante. Ate la arteria esplénica dos veces con seda 6-0, con los lazos distantes unos de otros. Diseccionar la arteria esplénica entre las 2 ligaduras. </li><li> Libera la arteria gástrica izquierda desde el tejido circundante. Ate la arteria gástrica izquierda dos veces con seda 6-0, con los lazos distantes unos de otros. Diseccionar la arteria entre las 2 ligaduras. </li><li> Circunscribir la vena cava inferior entre el riñón derecho y el lóbulo del hígado lateral derecha. Diseccionar la vena desde el espacio retroperitoneal. Exponer la aorta siguiendo el tronco celíaco. </li><li> Diseccionar el tejido adiposo retroperitoneal. Inyectar 1000 IE heparina en 1 ml de solución salina en la vena cava inferior. Retirar la cánula y cerrar la incisión con un algodón. Espere 1-2 min para el efecto sistémico de la heparina. </li><li> Circunscribir la aorta con pinzas. Diseccionar la aorta y Exsanguinate la rata. Además, diseccionar la vena cava inferior distalmente desde el riñón. </li></ol></li><li> Portal venosa Canulación (Use la cánula preparado en la sección 1.2) <ol><li> Haga una incisión peces aftosa en la vena porta distal. Abra la incisión con fórceps y canular la vena porta. Enjuague el hígado con 20 ml de solución de Ringer hasta que los decolora hígado y fijar la cánula con ligaduras (seda 6-0). </li></ol></li><li> Arterial canulación (Use la cánula preparado en la sección 1.3) <ol><li> Diseccionar la aorta por encima del tronco celíaco. Libera el segmento de aorta desde el espacio retroperitoneal. Cortar el segmento de aorta longitudinalmente para generar un parche aórtico. Inserte la cánula de construcción propia en un soporte estático. </li><li> Utilice 2 pinzas para deslizar el parche aórtico sobre la cánula. Ligar la arteria hepática con seda 6-0 sobre la cánula y fijar el parche en el pilar. </li></ol></li><li> Explantación Hígado <ol><li> Abra el diafragma, hacer una incisión circular y diseccionar el hígado a partir de las estructuras circundantes. </li></ol></li><li> Almacenamiento <ol><li> Store el hígado en un tanque de 500 ml estéril lleno de solución 350 ml de timbre hasta su uso. </li></ol></li></ol> 2. soluciones detergentes <ol><li> 10% de solución de Triton X-100 de stock <ol><li> Llene una botella de 1000 ml con 900 ml de agua destilada. y añadir 100 ml de Triton X-100 (99,9%). Utilice un agitador para disolver el Triton X-100. Llena la botella con agua destilada. hasta un volumen total de 1.000 ml se alcanza. </li></ol></li><li> 1% Triton X-100 <ol><li> Añadir 100 ml de la solución madre (10%) a una botella de 1000 ml. Añadir 900 ml de agua destilada. y agitar la botella dos veces. Filtrar la solución 1% de Triton X-100 a través de un filtro estéril. </li></ol></li><li> 10% de SDS de la Solución <ol><li> Llene una botella de 1000 ml con 900 ml de agua destilada. y añadir 66,99 g de SDS (99,9%, la densidad de 0,67). Utilice un agitador para disolver el SDS. Llena la botella con agua destilada. hasta un volumen total de 1.000 ml se alcanza. </li></ol></li><li> 1% de SDS <ol><li> Añadir 100 ml de la solución madre (10%) a un bot 1000 mltle. Añadir 900 ml de agua destilada. y agitar la botella dos veces. Se filtra la solución de SDS al 1% a través de un filtro estéril. </li></ol></li></ol> 3. Descelularización <ol><li> Puesta en marcha del dispositivo de perfusión <img alt="Figura 1" src="/files/ftp_upload/53029/53029fig1.jpg" /></li></ol> Figura 1:. Esquema del dispositivo de perfusión para Selectivo arterial y venoso portal perfusión de cuatro hígados de rata bajo oscilantes Condiciones Presión (. Modificado de Struecker et al 14) <ol><li> Enlace el drenaje a una llave de paso de tres vías y una extensión Heidelberger para regular el nivel de llenado y llenar el reactor con 500 ml de NaCl 0,9%. <img alt="Figura 2" src="/files/ftp_upload/53029/53029fig2.jpg" /></li></ol> Figura 2:. Esquema de la perfusión set-up link la cámara de perfusión (1,400 cm 3) (1) al extremo distal (4) de la trampa de burbujas (5) a través del acceso venoso portal (2) o a través de la ac arterialproceso (3). La trampa de burbujas (5) debe estar equipado con una obturación (4) en el extremo distal y un orificio de ventilación (6). Conectar la trampa de burbujas (5) a una extensión de Heidelberger (7). Enlazar la extensión Heidelberger al segmento de bomba (8). Además, conectar el segmento de bomba (8) a otra extensión Heidelberger (9). Inserte la última extensión Heidelberger (9) en la botella de solución de detergente (10). Conectar el respirador (11) a la cámara de perfusión (o al distribuidor de presión en el caso de múltiples perfusiones). Para drenar los fluidos del reactor, conecte la salida de la botella de residuos (12). <ol><li> Introduce el segmento de la bomba en la bomba. Arrancar la bomba para llenar el ciclo con PBS, cerrar el extremo distal de la trampa de burbujas y abrir el respiradero. Cuando la parte inferior de la burbuja está cubierto de forma segura con PBS (2-3 cm), cerrar el respiradero y abrir el extremo distal de la trampa de burbujas. </li><li> Instalación de hígado <ol><li> Enlazar la llave de tres vías de la cánula de la vena portal para el acceso reactor relacionada. Connect la cánula arterial para el acceso arterial. Tenga cuidado para asegurar que el aire no entra en los sistemas. </li></ol></li><li> Aplicación de oscilantes Condiciones Presión <ol><li> Use un respirador con una frecuencia de 15 lpm y una amplitud de 26 mbar (min. 4 mbar, máx. 30 mbar). Conectar el respirador a la cámara de distribución de la presión y conectar la cámara al reactor. Iniciar la aplicación de presión. </li></ol></li><li> Protocolo Descelularización <ol><li> Realice los pasos de perfusión con un caudal de 5 ml / min. Iniciar la descelularización con la perfusión del hígado con 1% de Triton X-100 durante 90 min. Permitir emanación de residuos a través de la salida del dispositivo de perfusión para mantener el nivel de fluido dentro de la cámara de perfusión constante y por encima del hígado perfundido. Después de 90 min, cambiar el detergente a 1% de SDS. <img alt="Figura 3" src="/files/ftp_upload/53029/53029fig3.jpg" /> <img alt="Mesa 1" src="/files/ftp_upload/53029/53029table1.jpg" /></li></ol></li></ol> &lt;p&gt; Figura 3: Protocolo de perfusión para todos los grupos experimentales.

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</ol>

The authors have nothing to disclose.

Aunque la técnica presentada para la cosecha de hígado de rata y descelularización es fácilmente reproducible, hay ciertos pasos críticos a considerar: Durante la preparación para la cosecha del hígado, es importante para evitar el sangrado grave porque va a activar la coagulación de la sangre y puede conducir a la formación de coágulos de sangre dentro del hígado. En nuestra opinión, es ventajoso incisión en la aorta abdominal directamente antes de la canulación de la vena por...

Descelularización y recelularización pueden permitir la generación de órganos funcionales, trasplantables in vitro 1. Mediante la eliminación de las células y material antigénico (por ejemplo., ADN, los epítopos alfa-gal) de un órgano, la matriz extracelular no o menos inmunogénico (ECM) se puede obtener. Esta matriz conserva la microanatomía tridimensional de un órgano y puede servir como la biomatriz ideal para repoblación con células de un origen diferente, posiblemente xenogénico 2. Por lo tanto, una matriz de hígado de rata descelularizado podría ser repoblado con células de hígado humano. Este micro-hígado humanizado podría servir como un modelo ex vivo para la investigación de enfermedades (por ejemplo., Enfermedades metabólicas congénitas, enfermedades virales o tumores malignos) o para las pruebas farmacéuticas preclínico 3. Varios protocolos diferentes para perfusión descelularización hígado de rata ya se han publicado 4-13. En todos los protocolos, decellularzación se logró mediante la perfusión de detergentes iónicos o no iónicos alcalinas través de la vena portal canulado. A lo mejor de nuestro conocimiento, fuimos el primer grupo reportar rata descelularización hígado por perfusión selectiva a través de la vena porta y / o la rata arteria hepática 14. Activación de la perfusión selectiva de los diferentes sistemas vasculares en el hígado puede permitir mejores resultados descelularización y, además, pueden desempeñar un papel importante en la repoblación celular. En el estudio se detalla aquí, los hígados se perfundieron en un dispositivo de perfusión de propiedad a medida, permitiendo la perfusión bajo condiciones de presión oscilantes. Estas condiciones de presión imitan la perfusión respiratoria dependiente fisiológica del hígado: in situ, el hígado cuelga bajo la cópula del diafragma, cuyo movimiento durante la respiración tiene un impacto directo en la perfusión del hígado. La inspiración conduce específicamente a la reducción del diafragma y apretando del hígado, optimizandoflujo de salida hepato-venosa, mientras que la expiración conduce a la elevación del hígado y disminución de la presión intraabdominal para optimizar flujo de entrada venosa portal-15. Nuestro objetivo fue evaluar si oscilantes condiciones de presión tienen un impacto en la homogeneidad de la perfusión descelularización hígado de rata imitando condiciones intraabdominales ex vivo. La homogeneidad del proceso de descelularización puede ser un factor subestimado en descelularización perfusión. Todos los agentes conocidos utilizan para Descelularización hígado causan alteraciones en el ECM. Las células en áreas mal perfundidas permanecen dentro de la ECM, mientras que otras áreas están ya completamente descelularizado. Para disolver las células restantes, la duración de la perfusión o la presión deben ser elevados, causando más alteraciones a las áreas bien perfundidos. Por lo tanto, los detergentes para descelularización deben ser distribuidos de forma homogénea dentro del órgano.

<table><tbody><tr><td colspan="4">Self built arterial cannula</td></tr><tr><td>&amp;nbsp;Portex Non Sterile Polyethene Tubing</td><td>SIMS Portex</td><td>REF 800/110/100</td><td>0.28 mm ID 0.61 mm OD</td></tr><tr><td>&amp;nbsp;Portex Non Sterile Polyethene Tubing</td><td>SIMS Portex</td><td>REF 800/110/200</td><td>0.58 mm ID 0.96 mm OD</td></tr><tr><td>Venodrop Safe butterfly catheter</td><td>Fresenius Kabi</td><td>3275851</td><td>21 G</td></tr><tr><td colspan="4">portal vein cannula</td></tr><tr><td>Periphereal Venous Catheter</td><td>BD</td><td>393224</td><td>BD Venflon Pro 20G</td></tr><tr><td>Three-way stopcock</td><td>smiths medical</td><td>888-101RE</td><td></td></tr><tr><td colspan="4">surgery</td></tr><tr><td>Cotton Sticks</td><td>Hecht-Assistent</td><td>4302</td><td></td></tr><tr><td>Cotton Pads&amp;nbsp;</td><td>Shaoxing Zhengde Surgical dressing</td><td>13H118-03</td><td></td></tr><tr><td>Gauze Bandage</td><td>Hubei Haige&amp;nbsp; Medical Instruments</td><td>14388</td><td></td></tr><tr><td>&amp;nbsp;Ringer Solution</td><td>Fresenius Kabi</td><td>13 HKP022</td><td>1000 ml</td></tr><tr><td>10 ml Syringe</td><td>Braun</td><td>4606108V</td><td>10 ml/ Luer Solo</td></tr><tr><td>5 ml Syringe</td><td>Braun</td><td>4606061V</td><td>5 ml /Luer Solo</td></tr><tr><td>Suture (Silk 6/0)</td><td>Resorba</td><td>H1F</td><td>LOT 105001.81</td></tr><tr><td>medical drape</td><td>Shaoxing Zhengde Surgical dressing</td><td>D0613011</td><td></td></tr><tr><td colspan="4">surgical instruments</td></tr><tr><td>needle holder</td><td>Geuder</td><td>17570</td><td></td></tr><tr><td>micro-forceps</td><td>Inox-Electronic</td><td>91150-20</td><td></td></tr><tr><td>micro-scissors</td><td>Martin</td><td>11-740-11</td><td></td></tr><tr><td>micro-forceps</td><td>S&amp;amp;T&amp;nbsp;</td><td>112314</td><td></td></tr><tr><td>Clamp</td><td>Aesculap</td><td>BH111R</td><td></td></tr><tr><td>scissors</td><td>F S T&amp;nbsp;</td><td>14501-14</td><td></td></tr><tr><td>surgical forceps</td><td>Aesculap</td><td>BD 557</td><td></td></tr><tr><td colspan="4">Decellularisation</td></tr><tr><td>Respirator</td><td>Resmed</td><td>14.24.11.0004</td><td>SmartAIR ST</td></tr><tr><td>Perfusion Device</td><td>Charite, medical engineering laboratory</td><td>custome-made device</td><td>decellularisation device</td></tr><tr><td>peristaltic pump ismatec reglo ICC</td><td>IDEX</td><td>ISM4408&amp;nbsp;</td><td>4-channel</td></tr><tr><td>heidelberger extension 75 cm&amp;nbsp;</td><td>Fresenius Kabi</td><td>2873</td><td>75 cm</td></tr><tr><td>MS/CA pump-segment</td><td>IDEX</td><td>IS 3510&amp;nbsp;</td><td>MS/CA/click&#039;n&#039;go/POM-C</td></tr><tr><td>CA 2-stopper tube</td><td>Pharmed</td><td>BPT NSF-51</td><td></td></tr><tr><td>bubble trap&amp;nbsp;</td><td></td><td>custome-made item</td><td></td></tr><tr><td>Luer Lock hose connector</td><td>Neolab</td><td>No. 02-1887</td><td></td></tr><tr><td colspan="4">Detergents</td></tr><tr><td>SDS pellets</td><td>Carl Roth&amp;nbsp;</td><td>CN30.4&amp;nbsp;</td><td>2.5 kg</td></tr><tr><td>Triton X-100</td><td>Carl Roth&amp;nbsp;</td><td>3051.1&amp;nbsp;</td><td>10 L</td></tr><tr><td>PBS&amp;nbsp;</td><td>Gibco</td><td>14190-094</td><td>DPBS</td></tr><tr><td colspan="4">staining</td></tr><tr><td>Eosin 1%</td><td>Morphisto</td><td>10177</td><td></td></tr><tr><td>Mayer hematoxylin</td><td>AppliChem</td><td>A4840</td><td></td></tr><tr><td>gomori staining</td><td>Morphisto</td><td>11104</td><td></td></tr><tr><td>AlcainBlue-PAS staining</td><td>Morphisto</td><td>11388</td><td></td></tr><tr><td>Direct Red 80&amp;nbsp;</td><td>Sigma Aldrich</td><td>365548</td><td></td></tr></tbody></table>

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.

La homogeneidad y por lo tanto la efectividad de diferentes protocolos de descelularización se evaluaron por observación macroscópica, el análisis histológico, y el análisis del contenido de ADN restante dentro de matrices de hígado descelularizados. Además, se realizó la colada de corrosión para visualizar la microanatomía de los hígados intactos después de descelularización. Macroscopía Durante descelularización, hígados convierten lucent, lo q...

Watch this Scientific Journal Video about Procedure for Decellularization of Rat Livers in an Oscillating-pressure Perfusion Device at JoVE.com

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

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.

Procedimiento para Descelularización de rata hígados en un dispositivo de perfusión oscilante presión

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

procedure-for-decellularization-rat-livers-an-oscillating-pressure

Research

JoVE Journal

Bioengineering

10.2K vistas.  Charité – Universitätsmedizin Berlin. 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.

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

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.

Descelularización y recelularización de hígados enteros

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 ...

Investigación

Bioingeniería

Technique of Subnormothermic Ex Vivo Liver Perfusion for the Storage, Assessment, and Repair of Marginal Liver Grafts

The success of liver transplantation has resulted in a dramatic organ shortage. In most transplant regions 20-30% of patients on the waiting list for liver transplantation die without receiving an organ transplant or are delisted for disease progression. One strategy to increase the donor pool is the utilization of marginal grafts, such as fatty livers, grafts from older donors, or donation after cardiac death (DCD). The current preservation technique of cold static storage is only poorly tolerated by marginal livers resulting in significant organ damage. In addition, cold static organ storage does not allow graft assessment or repair prior to transplantation.
These shortcomings of cold static preservation have triggered an interest in warm perfused organ preservation to reduce cold ischemic injury, assess liver grafts during preservation, and explore the opportunity to repair marginal livers prior to transplantation. The optimal pressure and flow conditions, perfusion temperature, composition of the perfusion solution and the need for an oxygen carrier has been controversial in the past.
In spite of promising results in several animal studies, the complexity and the costs have prevented a broader clinical application so far. Recently, with enhanced technology and a better understanding of liver physiology during ex vivo perfusion the outcome of warm liver perfusion has improved and consistently good results can be achieved.
This paper will provide information about liver retrieval, storage techniques, and isolated liver perfusion in pigs. We will illustrate a) the requirements to ensure sufficient oxygen supply to the organ, b) technical considerations about the perfusion machine and the perfusion solution, and c) biochemical aspects of isolated organs.

Technique of Subnormothermic Ex Vivo Liver Perfusion for the Storage, Assessment, and Repair of Marginal Liver Grafts

Marginal grafts, such as fatty livers, grafts from older donors, or livers retrieved after cardiac death (DCD) tolerate conventional, cold static storage only poorly. We developed a novel model of subnormothermic ex vivo liver perfusion for preservation, assessment, and repair of marginal liver grafts prior to transplantation.

Técnica de Subnormothermic<em&gt; Ex Vivo</em&gt; Perfusión hepática para el Almacenamiento, Evaluación y Reparación de marginales injertos hepáticos

The success of liver transplantation has resulted in a dramatic organ shortage. In most transplant regions 20-30% of patients on the waiting list for ...

Medicina

Normothermic Ex Vivo Liver Machine Perfusion in Mouse

This protocol presents an optimized erythrocytes-free NEVLP system using mouse livers. Ex vivo preservation of mouse livers was achieved by employing modified cannulas and techniques adapted from conventional commercial ex vivo perfusion equipment. The system was utilized to evaluate the preservation outcomes following 12 h of perfusion. C57BL/6J mice served as liver donors, and the livers were explanted by cannulating the portal vein (PV) and bile duct (BD), and subsequently flushing the organ with warm (37 &#176;C) heparinized saline. Then, the explanted livers were transferred to the perfusion chamber and subjected to normothermic oxygenated machine perfusion (NEVLP). Inlet and outlet perfusate samples were collected at 3 h intervals for perfusate analysis. Upon completion of the perfusion, liver samples were obtained for histological analysis, with morphological integrity assessed using modified Suzuki-Score through Hematoxylin-Eosin (HE) staining. The optimization experiments yielded the following findings: (1) mice weighing over 30 g were deemed more suitable for the experiment due to the larger size of their bile duct (BD). (2) a 2 Fr (outer diameter = 0.66 mm) polyurethane cannula was better suited for cannulating the portal vein (PV) when compared to a polypropylene cannula. This was attributed to the polyurethane material&#39;s enhanced grip, resulting in reduced catheter slippage during the transfer from the body to the organ chamber. (3) for cannulation of the bile duct (BD), a 1 Fr (outer diameter = 0.33 mm) polyurethane cannula was found to be more effective compared to the polypropylene UT - 03 (outer diameter = 0.30 mm) cannula. With this optimized protocol, mouse livers were successfully preserved for a duration of 12 h without significant impact on the histological structure. Hematoxylin-Eosin (HE) staining revealed a well-preserved morphological architecture of the liver, characterized by predominantly viable hepatocytes with clearly visible nuclei and mild dilation of hepatic sinusoids.

Normothermic Ex Vivo Liver Machine Perfusion in Mouse

A normothermic ex vivo liver perfusion (NEVLP) system was created for mouse livers. This system requires experience in microsurgery but allows for reproducible perfusion results. The ability to utilize mouse livers facilitates the investigation of molecular pathways to identify novel perfusate additives and enables the execution of experiments focused on organ repair.

Normothermic ex vivo liver machine perfusión en ratón

This protocol presents an optimized erythrocytes-free NEVLP system using mouse livers. Ex vivo preservation of mouse livers was achieved by employing ...

Ingeniería

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.

Una novedosa técnica quirúrgica como base para In Vivo parcial ingeniería hígado de rata

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

Isolation of Rat Portal Fibroblasts by In situ Liver Perfusion

Liver fibrosis is defined by the excessive deposition of extracellular matrix by activated myofibroblasts. There are multiple precursors of hepatic myofibroblasts, including hepatic stellate cells, portal fibroblasts and bone marrow derived fibroblasts 1. Hepatic stellate cells have been the best studied, but portal fibroblasts are increasingly recognized as important contributors to the myofibroblast pool, particularly in biliary fibrosis 2. Portal fibroblasts undergo proliferation in response to biliary epithelial injury, potentially playing a key role in the early stages of biliary scarring 3-5. A method of isolating portal fibroblasts would allow in vitro study of this cell population and lead to greater understanding of the role portal fibroblasts play in biliary fibrosis.
Portal fibroblasts have been isolated using various techniques including outgrowth 6, 7 and liver perfusion with enzymatic digestion followed by size selection 8. The advantage of the digestion and size selection technique compared to the outgrowth technique is that cells can be studied without the necessity of passage in culture. Here, we describe a modified version of the original technique described by Kruglov and Dranoff 8 for isolation of portal fibroblasts from rat liver that results in a relatively pure population of primary cells.

Isolation of Rat Portal Fibroblasts by In situ Liver Perfusion

A technique for isolating portal fibroblasts from rat liver is described. Livers are perfused and digested in situ with collagenase, followed by ex vivo digestion of the liver slurry and size selection of cells. This method provides a pure population of portal fibroblasts without the need for passage in culture.

El aislamiento de fibroblastos portales rata por<em&gt; In situ</em&gt; Hígado de perfusión

Liver fibrosis is defined  by the excessive deposition of extracellular matrix by activated  myofibroblasts. There are multiple precursors of hepatic ...

Biología

Isolation and Primary Culture of Rat Hepatic Cells

Primary hepatocyte culture is a valuable tool that has been extensively used in basic research of liver function, disease, pathophysiology, pharmacology and other related subjects. The method based on two-step collagenase perfusion for isolation of intact hepatocytes was first introduced by Berry and Friend in 1969 1 and, since then, has undergone many modifications. The most commonly used technique was described by Seglenin 1976 2. Essentially, hepatocytes are dissociated from anesthetized adult rats by a non-recirculating collagenase perfusion through the portal vein. The isolated cells are then filtered through a 100 &mu;m pore size mesh nylon filter, and cultured onto plates. After 4-hour culture, the medium is replaced with serum-containing or serum-free medium, e.g. HepatoZYME-SFM, for additional time to culture. These procedures require surgical and sterile culture steps that can be better demonstrated by video than by text. Here, we document the detailed steps for these procedures by both video and written protocol, which allow consistently in the generation of viable hepatocytes in large numbers.

Primary hepatocytes provide a valuable tool to evaluate biochemical, molecular, and metabolic functions in a physiologically relevant experimental system. We describe a reliable protocol for rat in situ liver perfusion, which consistently generates viable hepatocytes up to 1.0 &times; 108 cells per preparation with cell viability between 88 ~ 96%.

Aislamiento y cultivo primario de células hepáticas de ratas

Primary hepatocyte culture is a valuable tool that has been extensively used in basic research of liver function, disease, pathophysiology, pharmacology ...

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.

Obtención y descelularización de extremidades posteriores de ratas utilizando un biorreactor basado en perfusión ex vivo para alotrasplante compuesto vascularizado

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

A Small Animal Model of Ex Vivo Normothermic Liver Perfusion

There is a significant shortage of liver allografts available for transplantation, and in response the donor criteria have been expanded. As a result, normothermic ex vivo liver perfusion (NEVLP) has been introduced as a method to evaluate and modify organ function. NEVLP has many advantages in comparison to hypothermic and subnormothermic perfusion including reduced preservation injury, restoration of normal organ function under physiologic conditions, assessment of organ performance, and as a platform for organ repair, remodeling, and modification. Both murine and porcine NEVLP models have been described. We demonstrate a rat model of NEVLP and use this model to show one of its important applications &#8212; the use of a therapeutic molecule added to liver perfusate. Catalase is an endogenous reactive oxygen species (ROS) scavenger and has been demonstrated to decrease ischemia-reperfusion in the eye, brain, and lung. Pegylation has been shown to target catalase to the endothelium. Here, we added pegylated-catalase (PEG-CAT) to the base perfusate and demonstrated its ability to mitigate liver preservation injury. An advantage of our rodent NEVLP model is that it is inexpensive in comparison to larger animal models. A limitation of this study is that it does not currently include post-perfusion liver transplantation. Therefore, prediction of the function of the organ post-transplantation cannot be made with certainty. However, the rat liver transplant model is well established and certainly could be used in conjunction with this model. In conclusion, we have demonstrated an inexpensive, simple, easily replicable NEVLP model using rats. Applications of this model can include testing novel perfusates and perfusate additives, testing software designed for organ evaluation, and experiments designed to repair organs.

A Small Animal Model of Ex Vivo Normothermic Liver Perfusion

There is a significant liver donor shortage, and criteria for liver donors have been expanded. Normothermic ex vivo liver perfusion (NEVLP) has been developed to evaluate and modify organ function. This study demonstrates a rat model of NEVLP and tests the ability of pegylated-catalase, to mitigate liver preservation injury.

Un pequeño modelo de la perfusión hepática normotérmica Ex Vivo

There is a significant shortage of liver allografts available for transplantation, and in response the donor criteria have been expanded. As a result, ...

Isolation of Primary Rat Hepatocytes with Multiparameter Perfusion Control

Primary hepatocytes are widely used in basic research on liver diseases and for toxicity testing in vitro. The two-step collagenase perfusion procedure for primary hepatocyte isolation is technically challenging, especially in portal vein cannulation. The procedure is also prone to occasional contamination and variations in perfusion conditions due to difficulties in the assembly, optimization, or maintenance of the perfusion setup. Here, a detailed protocol for an improved two-step collagenase perfusion procedure with multiparameter perfusion control is presented. Primary rat hepatocytes were successfully and reliably isolated by taking the necessary technical precautions at critical steps of the procedure, and by reducing the operational difficulty and mitigating the variability of perfusion parameters through the adoption of a special intravenous catheter, standardized sterile disposable tubing, temperature control, and real-time monitoring and alarm system. The isolated primary rat hepatocytes consistently exhibit high cell viability (85%-95%), yield (2-5 x 108 cells per 200-300 g rat) and functionality (albumin, urea and CYP activity). The procedure was complemented by an integrated perfusion system, which is compact enough to be set up in the laminar flow hood to ensure aseptic operation.

This protocol details the use of a special intravenous catheter, standardized sterile disposable tubing, temperature control complemented by real-time monitoring, and an alarm system for two-step collagenase perfusion procedure to improve the consistency in the viability, yield, and functionality of isolated primary rat hepatocytes.

Aislamiento de hepatocitos primarios de rata con control de perfusión multiparamétrico

Primary hepatocytes are widely used in basic research on liver diseases and for toxicity testing in vitro. The two-step collagenase perfusion procedure ...

Evaluation of Apoptosis and Lung Injury in DCD Donor Lungs Preserved by EVLP

Establishment of a Novel Ex Vivo Lung Perfusion System for Rat Lungs After Circulatory Death

The increasing scarcity of donor lungs for transplantation has spurred significant interest in the utilization of organs procured from donors after cardiac death (DCD). However, a critical challenge remains in maximizing the number of viable lungs that meet stringent criteria for clinical use. Ex vivo lung perfusion (EVLP) emerges as a promising technology to evaluate and potentially improve the function of donated lungs. This paper describes the development of a cost-effective and reproducible small animal experimental platform specifically designed for EVLP research. This platform offers a high degree of customization, enabling researchers to tailor experimental parameters to address specific research questions within the field of EVLP. The team established a rat model to simulate DCD and implemented a two-stage preservation approach. Lungs were subjected to static cold storage using a perfusate solution at 4 &#176;C for 4 h, followed by normothermic EVLP for another 4 h. Researchers evaluated various lung function parameters, including pulmonary vascular resistance, pulmonary dynamic compliance, blood gas measurements of the perfusate, and apoptotic cell death in lung tissues. The study demonstrates that EVLP could significantly improve the functional performance of DCD lungs compared to simple cold storage at 4 &#176;C, suggesting that EVLP has the potential to mitigate ischemia-reperfusion injury and enhance graft function following circulatory death, thereby increasing the pool of transplantable lungs.

The objective is to develop a new ex vivo lung perfusion (EVLP) model in rats that can sustain consistent lung function for 4 h throughout EVLP and furnish the industry with implementation specifics that will offer a sturdy method for applying EVLP to rodent models.

The increasing scarcity of donor lungs for transplantation has spurred significant interest in the utilization of organs procured from donors after ...

Procedimiento para Descelularización de rata hígados en un dispositivo de perfusión oscilante presión

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