Este trabajo ha sido posible gracias a la Fundación de tejidos y células humanas de Investigación, lo que hace que los tejidos humanos disponibles para la investigación. Se recibió apoyo financiero para este trabajo por parte del Ministerio Federal de Educación e Investigación (nombre subvención: Virtual Network hígado, el número de concesión: 0.315.759) y Hepacult GmbH. También damos las gracias a los asistentes técnicos del Banco de tejidos Großhadern hospital para la recogida de las muestras de hígado y los asistentes técnicos del Fondo para el Core aislamiento de células para llevar a cabo la perfusión del hígado y el aislamiento de hepatocitos. En particular, nos gustaría dar las gracias a Natalja Löwen para demostrar este procedimiento en el video. Por último, nos gustaría dar las gracias a Natalja Löwen y Edeltraud Hanesch para la creación de las ilustraciones de la figura 1 y las figuras en el resumen esquemático del video.

1. Preparación de la perfusión y el aislamiento Soluciones <ol><li> Preparar las soluciones necesarias para la perfusión de la pieza hígado y el aislamiento de hepatocitos de acuerdo a la Tabla 1. Las soluciones pueden ser almacenadas a 4 ° C hasta su uso. </li><li> Filtro estéril todas las soluciones utilizando un filtro de 0,22 micras. </li><li> Todas las soluciones que entran en contacto con el hígado deben ser estériles. </li></ol> 2. Preparación de equipos y soluciones para infusión <ol><li> Equipamiento para la perfusión de la pieza de hígado debe establecerse como se muestra en la Figura 1. </li><li> El baño de agua se establece a una temperatura apropiada, que es diferente en cada particular, experimental, de tal manera que las soluciones están a la temperatura de 37 ° C cuando llegan a la pieza de hígado. En este caso, el baño de agua se fijó en 41 ° C para calentar las soluciones 1, 2 y 3 y el condensador de vidrio con camisa. Solución 4 debe calentarse hasta37 ° C en un baño de agua separada para su uso para reducir la pérdida de actividad de la colagenasa. </li><li> Poco antes de la perfusión del hígado, encienda el regulador del tanque de gas que contiene 95% O 2/5% CO 2 a gas del aparato de oxigenación (Figura 1E). </li></ol> 3. Perfusión del Hígado <ol><li> Un trozo de hígado con tanto cápsula intacta de Glisson posible e idealmente con superficie sólo 1 de corte se debe obtener de un patólogo para perfusión. </li><li> Coloque esta pieza de hígado en el embudo Büchner que contiene un disco de filtro perforada (Figura 1B). </li><li> El sistema de perfusión debe ser cebado con la solución 1. </li><li> Con un caudal bajo, cánulas de irrigación curvo con punta de oliva se debe insertar en los vasos sanguíneos más grandes en la superficie de corte de la pieza de hígado. Cuando la sangre limpia las del hígado, el tejido se vuelve más claro en áreas con buena perfusión. El número de cánulas utilizado para diversos tamañosde hígados se muestra en la Figura 2A. El tamaño relativa elegida debe resultar en un ajuste cómodo que sostendrá la cánula en su lugar. Los vasos sanguíneos más pequeños se deben dejar abiertos para el tampón de perfusión para drenar fuera de la pieza de hígado. </li><li> Aumentar la tasa de flujo en la bomba peristáltica a entre 110 a 460 ml / min dependiendo del tamaño del hígado (Figura 2B). Esto se traduce en una tasa media de flujo de 44 ± 16 ml / min por cánula (Figura 2C). La velocidad elegida depende de la pieza de hígado y debe resultar en un plumping ligero de la pieza de hígado. En algunos casos, puede ser necesario para sujetar cerró algunos de los vasos abiertos con pinzas vasculares micro para lograr el ligero voluminizador mencionado anteriormente. Una buena perfusión se puede observar cuando el pedazo de hígado es un color más claro en todo. </li><li> Mantenga la pieza de hígado húmedo durante la perfusión cubriéndola con una gasa empapada en solución salina. </li><li> Perfundir con 1 l de solución 1 para eliminar cualquier remaining sangre en la pieza de hígado. </li><li> Cambiar el fluido de perfusión a la Solución 2 y perfundir durante 10 min. </li><li> Cambie el líquido de perfusión a la Solución 3 y perfundir con 0,5 L. </li><li> Cambiar el fluido de perfusión a la Solución 4, que contiene 0,1-0,15% de la colagenasa (Tabla 2). </li><li> Para este paso, la perfusión debe llevarse a cabo de una manera de recirculación para 9-12 min o hasta que el hígado está lo suficientemente digerido; el tejido hepático debería aparecer a separarse ligeramente debajo de la cápsula de Glisson y sentir ablandado cuando se sondearon con el lado romo de un bisturí. </li></ol> 4. Aislamiento de los hepatocitos <ol><li> Apague la bomba peristáltica y extraiga las cánulas de la pieza de hígado. </li><li> Colocar la pieza de hígado en un plato de cristalización que contiene 100-200 ml de solución 5. </li><li> Retire la cápsula de Glisson con cuidado y suavidad sacudir las células. Si hay regiones que no están bien perfundidos, un bisturí se puede utilizar para cortar a travésestas regiones para liberar las células que contiene. Añadir más Solución 5 según sea necesario durante el proceso. </li><li> Añadir más solución de 5 hasta que se alcanza un volumen final de 500 ml. </li><li> Filtrar la suspensión celular dos veces; primero a través de una malla de 210 micras de nylon seguido de una malla de nylon 70 micras. A continuación, se vierte la suspensión celular en tubos de 200 ml de centrífuga. </li><li> Centrifugar la suspensión celular a 72 g durante 5 min a 4 ° C. Aspirar el sobrenadante y resuspender el sedimento celular suavemente suavemente en 200 ml de solución 5. </li><li> Repita el paso número lavado 4.6 tres veces. En el paso de centrifugación final, volver a suspender las células en una solución de almacenamiento en frío (ver la lista de materiales). Las células deben ser aproximadamente de 2-5 million hepatocitos por mililitro para la evaluación del rendimiento y la viabilidad mediante un ensayo de azul tripán exclusión basada en hemocitómetro. </li><li> Para llevar a cabo un ensayo de exclusión con azul de tripano, añadir 0,1 ml de células diluidas adecuadamente (≈ 2-5 million / ml) a un tubo de microcentrífuga que contiene 0,5 ml de azul de tripano solutien (0,4% de azul de tripano disolvió en solución salina tamponada con fosfato (PBS)) y 0,4 ml de PBS. Después de mezclar la suspensión de células a fondo, cargar un hemocitómetro con la suspensión y examinar bajo un microscopio a un aumento de 100X. Al examen microscópico, las células muertas se tiñen azul, mientras que las células vivas aparecen sin teñir. Contar el número de células vivas y totales en cada una de las 1 mm 2 cuadrículas marcadas en el hemocitómetro. Viabilidad (%), el rendimiento de las células vivas (millones de hepatocitos por la solución de almacenamiento en frío ml (CSS) o millones de hepatocitos por g de hígado) puede calcularse utilizando las fórmulas siguientes. </li></ol><img alt="Ecuación 1" fo:src="/files/ftp_upload/50615/50615eq1highres.jpg" src="/files/ftp_upload/50615/50615eq1.jpg" /> Nota: En este caso, el factor de dilución de azul de tripano es 10 y el factor de hemocitómetro es 10.000.

<ol>
	<li>Seglen, P. O. <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+isolated+rat+liver+cells.">Preparation of isolated rat liver cells.</a> Methods in Cell Biology. 13, 29-83 (1976).</li><li>Schneider, W. C., Potter, V. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+assay+of+animal+tissues+for+respiratory+enzymes+II.+Succinic+dehydrogenase+and+cytochrome+oxidase.">The assay of animal tissues for respiratory enzymes II. Succinic dehydrogenase and cytochrome oxidase.</a> J. Biol. Chem. 149, 217-227 (1943).</li><li>Aubin, P. M. G., Bucher, N. L. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Study+of+Binucleate+Cell+Counts+in+Resting+and+Regenerating+Rat+Liver+Employing+a+Mechanical+Method+for+the+Separation+of+Liver+Cells.">A Study of Binucleate Cell Counts in Resting and Regenerating Rat Liver Employing a Mechanical Method for the Separation of Liver Cells.</a> Anat. Rec. 112, 797-809 (1952).</li><li>Anderson, N. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Mass+Isolation+of+Whole+Cells+from+Rat+Liver.">The Mass Isolation of Whole Cells from Rat Liver.</a> Science. 117, 627-628 (1953).</li><li>Jacob, S. T., Bhargava, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+Method+for+Preparation+of+Liver+Cell+Suspensions.">New Method for Preparation of Liver Cell Suspensions.</a> Experimental Cell Research. 27 (62), 453-467 (1962).</li><li>Berry, M. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolic+Properties+of+Cells+Isolated+from+Adult+Mouse+Liver.">Metabolic Properties of Cells Isolated from Adult Mouse Liver.</a> Journal of Cell Biology. 15, 1-8 (1962).</li><li>Laws, J. O., Stickland, L. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metabolism+of+Isolated+Liver+Cells.">Metabolism of Isolated Liver Cells.</a> Nature. 178, 309-310 (1038).</li><li>Berry, M. N., Friend, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-yield+preparation+of+isolated+rat+liver+parenchymal+cells:+a+biochemical+and+fine+structural+study.">High-yield preparation of isolated rat liver parenchymal cells: a biochemical and fine structural study.</a> The Journal of Cell Biology. 43, 506-520 (1969).</li><li>Seglen, P. O. <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+Rat-Liver+Cells+.3.+Enzymatic+Requirements+for+Tissue+Dispersion.">Preparation of Rat-Liver Cells .3. Enzymatic Requirements for Tissue Dispersion.</a> Experimental Cell Research. 82 (73), 391-398 (1973).</li><li>Thasler, W. 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=Charitable+State-Controlled+Foundation+Human+Tissue+and+Cell+Research:+Ethic+and+Legal+Aspects+in+the+Supply+of+Surgically+Removed+Human+Tissue+For+Research+in+the+Academic+and+Commercial+Sector+in+Germany.">Charitable State-Controlled Foundation Human Tissue and Cell Research: Ethic and Legal Aspects in the Supply of Surgically Removed Human Tissue For Research in the Academic and Commercial Sector in Germany.</a> Cell and Tissue Banking. 4, 49-56 (2003).</li><li>Queral, A. E., DeAngelo, A. B., Garrett, C. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+different+collagenases+on+the+isolation+of+viable+hepatocytes+from+rat+liver.">Effect of different collagenases on the isolation of viable hepatocytes from rat liver.</a> Analytical Biochemistry. 138, 235-237 (1984).</li><li>Smedsrod, B., Pertoft, H. <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+Pure+Hepatocytes+and+Reticuloendothelial+Cells+in+High-Yield+from+a+Single-Rat+Liver+by+Means+of+Percoll+Centrifugation+and+Selective+Adherence.">Preparation of Pure Hepatocytes and Reticuloendothelial Cells in High-Yield from a Single-Rat Liver by Means of Percoll Centrifugation and Selective Adherence.</a> J. Leukocyte Biol. 38, 213-230 (1985).</li><li>Cantrell, E., Bresnick, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Benzpyrene+Hydroxylase-Activity+in+Isolated+Parenchymal+and+Nonparenchymal+Cells+of+Rat-Liver.">Benzpyrene Hydroxylase-Activity in Isolated Parenchymal and Nonparenchymal Cells of Rat-Liver.</a> Journal of Cell Biology. 52, 316-321 (1972).</li><li>Weiskirchen, R., Gressner, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+culture+of+hepatic+stellate+cells.">Isolation and culture of hepatic stellate cells.</a> Methods in Molecular Medicine. 117, 99-113 (2005).</li><li>Baccarani, U., 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=Steatotic+versus+cirrhotic+livers+as+a+source+for+human+hepatocyte+isolation.">Steatotic versus cirrhotic livers as a source for human hepatocyte isolation.</a> Transplant P. 33, 664-665 (2001).</li><li>Renz, J. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Utilization+of+extended+donor+criteria+liver+allografts+maximizes+donor+use+and+patient+access+to+liver+transplantation.">Utilization of extended donor criteria liver allografts maximizes donor use and patient access to liver transplantation.</a> Annals of Surgery. 242, 556-563 (2005).</li><li>Schemmer, 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=Extended+donor+criteria+have+no+negative+impact+on+early+outcome+after+liver+transplantation:+a+single-center+multivariate+analysis.">Extended donor criteria have no negative impact on early outcome after liver transplantation: a single-center multivariate analysis.</a> Transplant Proc. 39, 529-534 (2007).</li><li>Alexandre, 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=Influence+of+pre-,+intra-+and+post-operative+parameters+of+donor+liver+on+the+outcome+of+isolated+human+hepatocytes.">Influence of pre-, intra- and post-operative parameters of donor liver on the outcome of isolated human hepatocytes.</a> Cell and Tissue Banking. 3, 223-233 (2002).</li><li>Spotnitz, W. D., Burks, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=State-of-the-art+review:+Hemostats,+sealants,+and+adhesives+II:+Update+as+well+as+how+and+when+to+use+the+components+of+the+surgical+toolbox.">State-of-the-art review: Hemostats, sealants, and adhesives II: Update as well as how and when to use the components of the surgical toolbox.</a> Clinical and applied thrombosis/hemostasis : official journal of the International Academy of Clinical and Applied Thrombosis/Hemostasis. 16, 497-514 (2010).</li><li>Spotnitz, W. D., Burks, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hemostats,+sealants,+and+adhesives+III:+a+new+update+as+well+as+cost+and+regulatory+considerations+for+components+of+the+surgical+toolbox.">Hemostats, sealants, and adhesives III: a new update as well as cost and regulatory considerations for components of the surgical toolbox.</a> Transfusion. 52, 2243-2255 (2012).</li><li>Toriumi, D. M., Raslan, W. F., Friedman, M., Tardy, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Histotoxicity+of+cyanoacrylate+tissue+adhesives.+A+comparative+study.">Histotoxicity of cyanoacrylate tissue adhesives. A comparative study.</a> Archives of otolaryngology--head &amp; neck surgery. 116, 546-550 (1990).</li><li>Vinters, H. V., Galil, K. A., Lundie, M. J., Kaufmann, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+histotoxicity+of+cyanoacrylates.+A+selective+review.">The histotoxicity of cyanoacrylates. A selective review.</a> Neuroradiology. 27, 279-291 (1985).</li><li>Bhogal, R. 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=Isolation+of+primary+human+hepatocytes+from+normal+and+diseased+liver+tissue:+a+one+hundred+liver+experience.">Isolation of primary human hepatocytes from normal and diseased liver tissue: a one hundred liver experience.</a> PloS ONE. 6, e18222 (2011).</li><li>Olson, 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=Concordance+of+the+toxicity+of+pharmaceuticals+in+humans+and+in+animals.">Concordance of the toxicity of pharmaceuticals in humans and in animals.</a> Regul. Toxicol. Pharm. 32, 56-67 (2000).</li><li>Koebe, H. G., Pahernik, S. A., Sproede, M., Thasler, W. E., Schildberg, F. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Porcine+hepatocytes+from+slaughterhouse+organs.+An+unlimited+resource+for+bioartificial+liver+devices.">Porcine hepatocytes from slaughterhouse organs. An unlimited resource for bioartificial liver devices.</a> ASAIO Journal. 41, 189-193 (1995).</li><li>Russell, W. M. S., Burch, R. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The principles of humane experimental technique. , (1959).</li></ol>

La optimización de este protocolo fue parcialmente financiado por una subvención del Hepacult GmbH. Dr. Wolfgang Thasler es uno de los fundadores de Hepacult GmbH y sigue siendo uno de los miembros de la junta directiva de esta empresa. El empleo de Maresa Demmel es parcialmente por Hepacult. Maria Hauner es empleado por Hepacult GmbH. Hepacult es un spin-off de la firma biotecnológica de la Universidad, que ofrece los hepatocitos humanos con el consentimiento y el libre acceso con fines de investigación.

Este protocolo da como resultado el aislamiento de hepatocitos humanos con una alta viabilidad y pureza. Con el fin de alcanzar estos resultados, es importante comenzar con una pieza adecuada de hígado. El trozo de hígado debe tener la cápsula de Glisson intacta en todas las superficies excepto por 1 superficie de corte. Otro factor importante es el lote particular de colagenasa utilizado, como diferentes lotes pueden dar lugar a marcadas diferencias en viabilidades de los hepatocitos después de la digestión 1...

A correction was made to: <a href="http://www.jove.com/video/50615/isolation-human-hepatocytes-two-step-collagenase-perfusion">Isolation of Human Hepatocytes by a Two-step Collagenase Perfusion Procedure </a>
The changes listed below have been made to Table 1.
1). In the recipe for Solution 2, the Final Concentration of EGTA has been changed from:
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td></td>
			<td>EGTA&#160;</td>
			<td>0.1mM</td>
		</tr>
	</tbody>
</table>
to:
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td></td>
			<td>EGTA&#160;</td>
			<td>1mM</td>
		</tr>
	</tbody>
</table>
2). In the recipes for Solution 3 and 4, the Final Concentration of Calcium chloride dihydrate has been changed from:
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td></td>
			<td>Calcium chloride dihydrate&#160;</td>
			<td>0.5&#181;M</td>
		</tr>
	</tbody>
</table>
to:
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td></td>
			<td>Calcium chloride dihydrate&#160;</td>
			<td>5mM</td>
		</tr>
	</tbody>
</table>

A correction was made to: Isolation of Human Hepatocytes by a Two-step Collagenase Perfusion Procedure.
The Final Concentration of EGTA in Solution 2 and the Final Concentration of Calcium chloride dihydrate in solutions 3 and 4 have been updated in Table 1.

Erratum: Isolation of Human Hepatocytes by a Two-step Collagenase Perfusion Procedure

Una suspensión de células de hígado puede prepararse a partir del hígado por métodos mecánicos o enzimáticos. Los métodos mecánicos utilizados para preparar las células del hígado enteros incluyen obligar al hígado a través de una gasa 2, agitando un trozo de hígado con perlas de vidrio en un agitador de Kahn 3, utilizando homogeneizadores de vidrio con morteros sueltas 4,5 etc Con los años, los métodos mecánicos han caído en favor debido a los daños a las membranas celulares y la pérdida de función de los hepatocitos aislados 6,7. En consecuencia, el uso de un método enzimático es actualmente el principal método para el aislamiento de hepatocitos. Aislamiento de hepatocitos utilizando un método enzimático mejoró notablemente cuando Berry y Friend 8 perfundidos colagenasa y hialuronidasa a través del hígado a través de la vena porta en ratas. Este proceso utiliza la perfusión de la vasculatura para permitir que las enzimas entran en estrecho contacto con la mayoría de las células, conduciendo aun aumento de 6 veces en el rendimiento de hepatocitos 8. Además, este método produjo células que conservan su integridad estructural, prácticamente sin transformación del retículo endoplásmico en vesículas aisladas y ningún daño mitocondrial 8. Este método se modificó por Seglen 1, que fue pionero en un procedimiento de perfusión en dos etapas para el aislamiento de células del hígado. En este procedimiento, el hígado de la rata se perfunde con un tampón de Ca2 + libre seguido de la perfusión con un tampón de colagenasa que contiene Ca 2 + 1. La eliminación de Ca 2 + en la primera etapa ayuda a romper los desmosomas, mientras que se requiere la adición de Ca 2 + en el segundo paso para la actividad de la colagenasa óptimo 1,9. Dado que el trabajo publicado descrito anteriormente se ha realizado en ratas, este artículo tiene como objetivo demostrar un procedimiento modificado que se puede utilizar para el aislamiento de hepatocitos con alta viabilidad de zumbidoun hígados. El uso de hepatocitos humanos sigue siendo importante para la investigación traslacional y para la validación de los experimentos con modelos animales. Los pedazos de hígado humano utilizados en este estudio fueron obtenidas con el consentimiento de la gobernanza a través de la Fundación Tejido Humano y la investigación con células, una fundación sin fines de lucro controladas por el Estado 10. Después de un patólogo elimina lo que se requiere para el diagnóstico, pedazos de hígado se recogieron a partir del tejido restante. El tejido seccionado por el patólogo era morfológicamente tejido sano obtenido a partir de los márgenes de resección después de la resección hepática.

<table border="1">
	<tbody>
		<tr>
			<td>Name of Reagent/Material</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>Bubble trap</td>
			<td>Ga&szlig;ner Glastechnik</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Glass jacketed condenser</td>
			<td>Ga&szlig;ner Glastechnik</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>41 &deg;C Water bath</td>
			<td>Julabo</td>
			<td>35723-H24/EG</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>37 &deg;C Water bath</td>
			<td>GFL</td>
			<td>1083</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Compressed gas cylinder (95 % O2/5 % CO2)</td>
			<td>Linde</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Gas permeable tubing</td>
			<td>Neolab</td>
			<td>2-4440</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Peristaltic pump</td>
			<td>Ismatec</td>
			<td>IP65</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Scalpel</td>
			<td>Feather</td>
			<td>320010</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Forceps</td>
			<td>Omnilab</td>
			<td>5171014</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Conical flasks 1 L</td>
			<td>Schott Duran</td>
			<td>2121654</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Conical flasks 5 L</td>
			<td>Schott Duran</td>
			<td>2121673</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Beakers</td>
			<td>Schott Duran</td>
			<td>2110654</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>200 ml centrifuge tubes</td>
			<td>Becton Dickinson</td>
			<td>352075</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Crystallizing dish</td>
			<td>Omnilab</td>
			<td>5144063</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Curved irrigation cannulae with ball tips</td>
			<td>Ernst Kratz GmbH</td>
			<td>1464LL/ 1465LL A+B/ 1472LL</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Micro vascular clamps</td>
			<td>Ernst Kratz GmbH</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>B&uuml;chner funnel</td>
			<td>Carl Roth</td>
			<td>HT38.1</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Nylon mesh 210 &mu;m</td>
			<td>Neolab</td>
			<td>4-1413</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Nylon mesh 70 &mu;m</td>
			<td>Neolab</td>
			<td>4-1419</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>0.22 &mu;m sterile filters</td>
			<td>Peske</td>
			<td>99505</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>500 ml bottles</td>
			<td>Schott Duran</td>
			<td>2180144</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>1 L bottles</td>
			<td>Schott Duran</td>
			<td>2180154</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Hemocytometer</td>
			<td>Peske</td>
			<td>06-0001</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>1.5 ml tubes</td>
			<td>Eppendorf</td>
			<td>0030 120,086</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>50 ml conical tubes</td>
			<td>BD Biosciences</td>
			<td>352070</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Ice bucket</td>
			<td>Neolab</td>
			<td>1508454</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Sterile Pasteur pipettes</td>
			<td>Brand</td>
			<td>747715</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Motorised pipette filler (Pipette boy acu)</td>
			<td>Integra</td>
			<td>155017</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Refridgerated centrifuge</td>
			<td>Eppendorf</td>
			<td>5810R</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Laminar flow</td>
			<td>Kendro</td>
			<td>Hera safe-KS9</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Aspirator (Low-flow surgical suction pump)</td>
			<td>Atmos</td>
			<td>C361</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Laboratory Gas Burner</td>
			<td>Integra</td>
			<td>Fire Boy eco</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Disposable laboratory coat</td>
			<td>Paperlynen GmbH</td>
			<td>MD0202414</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Surgical mask with visor</td>
			<td>Kimberly-Clark</td>
			<td>48247</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Surgical hood</td>
			<td>Barrier</td>
			<td>42072</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Latex gloves</td>
			<td>Semper Care</td>
			<td>CE0321</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Collagenase (Batch number NB 4G)</td>
			<td>Serva</td>
			<td>17465</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Calcium chloride dihydrate</td>
			<td>Merck</td>
			<td>2382</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>EGTA</td>
			<td>Sigma</td>
			<td>E4378</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Roth</td>
			<td>9265.2</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Hepes</td>
			<td>Roth</td>
			<td>9105.3</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Potassium chloride</td>
			<td>Serva</td>
			<td>26868</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Albumin</td>
			<td>Biomol</td>
			<td>01400-2</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Serva</td>
			<td>22700</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Sodium hydrogen carbonate</td>
			<td>Serva</td>
			<td>30180</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>0.4% Trypan blue solution</td>
			<td>Lonza</td>
			<td>17-942E</td>
			<td>&nbsp;</td>
		</tr>
		<tr>
			<td>Cold storage solution</td>
			<td>Hepacult GmbH</td>
			<td>&nbsp;</td>
			<td>&nbsp;</td>
		</tr>
	</tbody>
</table>

isolation of human hepatocytes by a two-step collagenase perfusion procedure

El hígado, un órgano con una capacidad de regeneración excepcional, lleva a cabo una amplia gama de funciones, tales como la desintoxicación, el metabolismo y la homeostasis. Como tal, los hepatocitos son un modelo importante para una gran variedad de preguntas de investigación. En particular, el uso de hepatocitos humanos es especialmente importante en los campos de la farmacocinética, la toxicología, la regeneración del hígado y la investigación de translación. Por lo tanto, este método presenta una versión modificada de un procedimiento de perfusión con colagenasa de dos etapas para aislar los hepatocitos como se ha descrito por Seglen 1. Anteriormente, los hepatocitos han sido aislados por métodos mecánicos. Sin embargo, los métodos enzimáticos han demostrado ser superior como hepatocitos conservan su integridad y función estructural después del aislamiento. Este método que aquí se presenta se adapta el método previamente diseñado para hígados de rata a pedazos de hígado humano y los resultados en un gran rendimiento de hepatocitos con una viabilidad de 77 ± 10%. La principaldiferencia en este procedimiento es el proceso de cannulization de los vasos sanguíneos. Además, el método descrito aquí también se puede aplicar a los hígados de otras especies con tamaños de hígado o de los vasos sanguíneos comparables.

Configuración de perfusión El equipo necesario para la perfusión hepática debe establecerse de acuerdo con la figura 1. Viabilidad y Rentabilidad de hepatocitos aislados de humanos La viabilidad media de hepatocitos humanos aislados fue de 77 ± 10% y el rendimiento promedio de los hepatocitos fue de 13 ± 11 millones hepatocitos / g de hígado, con los valores expresados ​​como medias ± desviación estándar. El n...

Watch this Scientific Journal Video about Isolation of Human Hepatocytes by a Two-step Collagenase Perfusion Procedure at JoVE.com

Isolation of Human Hepatocytes by a Two-step Collagenase Perfusion Procedure

Se describe un procedimiento de perfusión con colagenasa de dos etapas modificado para el aislamiento de hepatocitos humanos. Este método también se puede aplicar a otros hígados de mamíferos. Los hepatocitos aislados están disponibles con un alto rendimiento y la viabilidad, por lo que un modelo adecuado para la investigación científica en áreas como la regeneración hepática, farmacocinética y toxicología.

El aislamiento de hepatocitos humanos por una colagenasa perfusión Procedimiento de dos pasos

The liver, an organ with an exceptional regeneration capacity, carries out a wide range of functions, such as detoxification, metabolism and homeostasis. ...

isolation-human-hepatocytes-two-step-collagenase-perfusion

Research

JoVE Journal

Biology

30.8K vistas.  Grosshadern Hospital, Munich.  Se describe un procedimiento de perfusión con colagenasa de dos etapas modificado para el aislamiento de hepatocitos humanos. Este método también se puede aplicar a otros hígados de mamíferos. Los hepatocitos aislados están disponibles con un alto rendimiento y la viabilidad, por lo que un modelo adecuado para la investigación científica en áreas como la regeneración hepática, farmacocinética y toxicología. 

Video: Isolation of Human Hepatocytes by a Two-step Collagenase Perfusion Procedure

Derivation of Human Embryonic Stem Cells by Immunosurgery

The ability of human embryonic stem cells to self-renew and differentiate into all cell types of 
the body suggests that they hold great promise for both medical applications and as a research 
tool for addressing fundamental questions in development and disease. Here, we provide a 
concise, step-by-step protocol for the derivation of human embryonic stem cells from embryos 
by immunosurgical isolation of the inner cell mass. 


The ability of human embryonic stem cells to self-renew and differentiate into all cell types of 
the body suggests that they hold great promise for both medical applications and as a research 
tool for addressing fundamental questions in development and disease. Here, we provide a 
concise, step-by-step protocol for the derivation of human embryonic stem cells from embryos 
by immunosurgical isolation of the inner cell mass.

Derivación de células estaminales embrionarias humanas por Immunosurgery

The ability of human embryonic stem cells to self-renew and differentiate into all cell types of 
the body suggests that they hold great promise for both ...

Investigación

Biología

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 ...

Mouse Islet of Langerhans Isolation using a Combination of Purified Collagenase and Neutral Protease

The interrogation of beta cell gene expression and function in vitro has squarely shifted over the years from the study of rodent tumorigenic cell lines to the study of isolated rodent islets. Primary islets offer the distinct advantage that they more faithfully reflect the biology of intracellular signaling pathways and secretory responses. Whereas the method of islet isolation using tissue dissociating enzyme (TDE) preparations has been well established in many laboratories1-4, variations in the consistency of islet yield and quality from any given rodent strain limit the extent and feasibility of primary islet studies. These variations often occur as a result of the crude partially purified TDEs used in the islet isolation procedure; TDEs frequently exhibit lot-to-lot variations in activity and often require adjustments to the dose of enzyme used. A small number of reports have used purified TDEs for rodent cell isolations5, 6, but the practice is not widespread despite the routine use and advantages of purified TDEs for human islet isolations. In collaboration with VitaCyte, LLC (Indianapolis, IN), we developed a modified mouse islet isolation protocol based on that described by Gotoh7, 8, in which the TDEs are perfused directly into the pancreatic duct of mice, followed by crude tissue fractionation through a Histopaque gradient9, and isolation of purified islets. A significant difference in our protocol is the use of purified collagenase (CIzyme MA) and neutral protease (CIzyme BP) combination. The collagenase was characterized by the use of a6 fluorescence collagen degrading activity (CDA) assay that utilized fluorescently labeled soluble calf skin fibrils as substrate6. This substrate is more predictive of the kinetics of collagen degradation in the tissue matrix because it relies on native collagen as the substrate. The protease was characterized with a sensitive fluorescent kinetic assay10. Utilizing these improved assays along with more traditional biochemical analysis enable the TDE to be manufactured more consistently, leading to improved performance consistency between lots. The protocol described in here was optimized for maximal islet yield and optimal islet morphology using C57BL/6 mice. During the development of this protocol, several combinations of collagenase and neutral proteases were evaluated at different concentrations, and the final ratio of collagenase:neutral protease of 35:10 represents enzyme performance comparable to Sigma Type XI. Because significant variability in average islet yields from different strains of rats and mice have been reported, additional modifications of the TDE composition should be made to improve the yield and quality of islets recovered from different species and strains.

A detailed description of mouse islet isolation is described using the technique of in situ pancreatic ductal cannulation and perfusion of a combination of purified collagenase and neutral protease.

Aislamiento de ratón Islet Langerhans utilizando una combinación de colagenasa purificada y proteasa neutra

The interrogation of beta cell gene expression and function in vitro has squarely shifted over the years from the study of rodent tumorigenic cell lines ...

GST-His purification: A Two-step Affinity Purification Protocol Yielding Full-length Purified Proteins

Key assays in enzymology for the biochemical characterization of proteins in vitro necessitate high concentrations of the purified protein of interest. Protein purification protocols should combine efficiency, simplicity and cost effectiveness1. Here, we describe the GST-His method as a new small-scale affinity purification system for recombinant proteins, based on a N-terminal Glutathione Sepharose Tag (GST)2,3 and a C-terminal 10xHis tag4, which are both fused to the protein of interest. The latter construct is used to generate baculoviruses, for infection of Sf9 infected cells for protein expression5. GST is a rather long tag (29 kDa) which serves to ensure purification efficiency. However, it might influence physiological properties of the protein. Hence, it is subsequently cleaved off the protein using the PreScission enzyme6. In order to ensure maximum purity and to remove the cleaved GST, we added a second affinity purification step based on the comparatively small His-Tag. Importantly, our technique is based on two different tags flanking the two ends of the protein, which is an efficient tool to remove degraded proteins and, therefore, enriches full-length proteins. The method presented here does not require an expensive instrumental setup, such as FPLC. Additionally, we incorporated MgCl2 and ATP washes to remove heat shock protein impurities and nuclease treatment to abolish contaminating nucleic acids. In summary, the combination of two different tags flanking the N- and the C-terminal and the capability to cleave off one of the tags, guaranties the recovery of a highly purified and full-length protein of interest.

In the present protocol, we demonstrate a highly efficient and cost-effective small-scale protein purification method, which allows purification of recombinant proteins by uniquely combining a cleavable GST-tag and a small His-tag.

GST-Su purificación: A dos pasos Affinity Protocolo Purificación Cediendo largos proteínas purificadas

Key assays in enzymology for the biochemical characterization of proteins in vitro necessitate high concentrations of the purified protein of interest. ...

Examination of Drosophila Larval Tracheal Terminal Cells by Light Microscopy

Cell shape is critical for cell function. However, despite the importance of cell morphology, little is known about how individual cells generate specific shapes. Drosophila tracheal terminal cells have become a powerful genetic model to identify and elucidate the roles of genes required for generating cellular morphologies. Terminal cells are a component of a branched tubular network, the tracheal system that functions to supply oxygen to internal tissues. Terminal cells are an excellent model for investigating questions of cell shape as they possess two distinct cellular architectures. First, terminal cells have an elaborate branched morphology, similar to complex neurons; second, terminal cell branches are formed as thin tubes and contain a membrane-bound intracellular lumen. Quantitative analysis of terminal cell branch number, branch organization and individual branch shape, can be used to provide information about the role of specific genetic mechanisms in the making of a branched cell. Analysis of tube formation in these cells can reveal conserved mechanisms of tubulogenesis common to other tubular networks, such as the vertebrate vasculature. Here we describe techniques that can be used to rapidly fix, image, and analyze both branching patterns and tube formation in terminal cells within Drosophila larvae. These techniques can be used to analyze terminal cells in wild-type and mutant animals, or genetic mosaics. Because of the high efficiency of this protocol, it is also well suited for genetic, RNAi-based, or drug screens in the Drosophila tracheal system.

Examination of Drosophila Larval Tracheal Terminal Cells by Light Microscopy

Here, we present a method for light microscopy analysis of tracheal terminal cells in Drosophila larvae. This method allows for quick examination of branch and lumen morphology in whole animals and would be useful for analysis of individual mutants or screens for mutations affecting terminal cell development.

El examen de<em&gt; Drosophila</em&gt; Larvas células traqueales de terminales por microscopía de luz

Cell shape is critical for cell function. However, despite the importance of cell morphology, little is known about how individual cells generate specific ...

Protocol for Isolation of Primary Human Hepatocytes and Corresponding Major Populations of Non-parenchymal Liver Cells

Beside parenchymal hepatocytes, the liver consists of non-parenchymal cells (NPC) namely Kupffer cells (KC), liver endothelial cells (LEC) and hepatic Stellate cells (HSC). Two-dimensional (2D) culture of primary human hepatocyte (PHH) is still considered as the &#34;gold standard&#34; for in vitro testing of drug metabolism and hepatotoxicity. It is well-known that the 2D monoculture of PHH suffers from dedifferentiation and loss of function. Recently it was shown that hepatic NPC play a central role in liver (patho-) physiology and the maintenance of PHH functions. Current research focuses on the reconstruction of in vivo tissue architecture by 3D- and co-culture models to overcome the limitations of 2D monocultures. Previously we published a method to isolate human liver cells and investigated the suitability of these cells for their use in cell cultures in Experimental Biology and Medicine1. Based on the broad interest in this technique the aim of this article was to provide a more detailed protocol for the liver cell isolation process including a video, which will allow an easy reproduction of this technique.
Human liver cells were isolated from human liver tissue samples of surgical interventions by a two-step EGTA/collagenase P perfusion technique. PHH were separated from the NPC by an initial centrifugation at 50 x g. Density gradient centrifugation steps were used for removal of dead cells. Individual liver cell populations were isolated from the enriched NPC fraction using specific cell properties and cell sorting procedures. Beside the PHH isolation we were able to separate KC, LEC and HSC for further cultivation.
Taken together, the presented protocol allows the isolation of PHH and NPC in high quality and quantity from one donor tissue sample. The access to purified liver cell populations could allow the creation of in vivo like human liver models.

A technique to isolate human hepatocytes and non-parenchymal liver cells from the same donor is described. The different liver cell types build the basis for functional liver models and tissue engineering. This new method aims to isolate liver cells in a high yield and viability.

Protocolo para el aislamiento de hepatocitos primarios humanos y la correspondiente principales poblaciones de células hepáticas no parenquimatosas

Beside parenchymal hepatocytes, the liver consists of non-parenchymal cells (NPC) namely Kupffer cells (KC), liver endothelial cells (LEC) and hepatic ...

Microbiota Analysis Using Two-step PCR and Next-generation 16S rRNA Gene Sequencing

The human gut is colonized by trillions of bacteria that support physiologic functions such as food metabolism, energy harvesting, and regulation of the immune system. Perturbation of the healthy gut microbiome has been suggested to play a role in the development of inflammatory diseases, including multiple sclerosis (MS). Environmental and genetic factors can influence the composition of the microbiome; therefore, identification of microbial communities linked with a disease phenotype has become the first step towards defining the microbiome&#8217;s role in health and disease. Use of 16S rRNA metagenomic sequencing for profiling bacterial community has helped in advancing microbiome research. Despite its wide use, there is no uniform protocol for 16S rRNA-based taxonomic profiling analysis. Another limitation is the low resolution of taxonomic assignment due to technical difficulties such as smaller sequencing reads, as well as use of only forward (R1) reads in the final analysis due to low quality of reverse (R2) reads. There is need for a simplified method with high resolution to characterize bacterial diversity in a given biospecimen. Advancements in sequencing technology with the ability to sequence longer reads at high resolution have helped to overcome some of these challenges. Present sequencing technology combined with a publicly available metagenomic analysis pipeline such as R-based Divisive Amplicon Denoising Algorithm-2 (DADA2) has helped advance microbial profiling at high resolution, as DADA2 can assign sequence at the genus and species levels. Described here is a guide for performing bacterial profiling using two-step amplification of the V3-V4 region of the 16S rRNA gene, followed by analysis using freely available analysis tools (i.e., DADA2, Phyloseq, and METAGENassist). It is believed that this simple and complete workflow will serve as an excellent tool for researchers interested in performing microbiome profiling studies.

Described here is a simplified standard operating procedure for microbiome profiling using 16S rRNA metagenomic sequencing and analysis using freely available tools. This protocol will help researchers who are new to the microbiome field as well as those requiring updates on methods to achieve bacterial profiling at a higher resolution.

Análisis de microbiota utilizando PCR de dos pasos y secuenciación genética de rRNA 16S de próxima generación

The human gut is colonized by trillions of bacteria that support physiologic functions such as food metabolism, energy harvesting, and regulation of the ...

A Two-Step Strategy that Combines Epigenetic Modification and Biomechanical Cues to Generate Mammalian Pluripotent Cells

Cell phenotype can be reversed or modified with different methods, with advantages and limitations that are specific for each technique. Here we describe a new strategy that combines the use of chemical epigenetic erasing with mechanosensing-related cues, to generate mammalian pluripotent cells. Two main steps are required. In the first step, adult mature (terminally differentiated) cells are exposed to the epigenetic eraser 5-aza-cytidine to drive them into a pluripotent state. This part of the protocol was developed, based on the increasing understanding of the epigenetic mechanisms controlling cell fate and differentiation, and involves the use of the epigenetic modifier to erase cell differentiated state and then drive into a transient high plasticity window.
In the second step, erased cells are encapsulated in polytetrafluoroethylene (PTFE) micro-bioreactors, also known as Liquid Marbles, to promote 3D cell rearrangement to extend and stably maintain the acquired high plasticity. PTFE is a non-reactive hydrophobic synthetic compound and its use permits the creation of a cellular microenvironment, which cannot be achieved in traditional 2D culture systems. This system encourages and boosts the maintenance of pluripotency though bio-mechanosensing-related cues.
The technical procedures described here are simple strategies to allow for the induction and maintenance of a high plasticity state in adult somatic cells. The protocol allowed the derivation of high plasticity cells in all mammalian species tested. Since it does not involve the use of gene transfection and is free of viral vectors, it may represent a notable technological advance for translational medicine applications. Furthermore, the micro-bioreactor system provides a notable advancement in stem cell organoid technology by in vitro re-creating a specific micro-environment that allows for the long-term culture of high plasticity cells, namely as ESCs, iPSCs, epigenetically erased cells and MSCs.

We here present a method that combines the use of chemical epigenetic erasing with mechanosensing-related cues to efficiently generate mammalian pluripotent cells, without the need of gene transfection or retroviral vectors. This strategy is, therefore, promising for translational medicine and represents a notable advancement in stem cell organoid technology.

Una estrategia de dos pasos que combina la modificación epigenética y las señales biomecánicas para generar células pluripotentes de mamíferos

Cell phenotype can be reversed or modified with different methods, with advantages and limitations that are specific for each technique. Here we describe ...

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 ...

Cuantificación mejorada de proteínas mediante el aislamiento mitocondrial en dos pasos

Two-Step Tag-Free Isolation of Mitochondria for Improved Protein Discovery and Quantification

Most physiological and disease processes, from central metabolism to immune response to neurodegeneration, involve mitochondria. The mitochondrial proteome is composed of more than 1,000 proteins, and the abundance of each can vary dynamically in response to external stimuli or during disease progression. Here, we describe a protocol for isolating high-quality mitochondria from primary cells and tissues. The two-step procedure comprises (1) mechanical homogenization and differential centrifugation to isolate crude mitochondria, and (2) tag-free immune capture of mitochondria to isolate pure organelles and eliminate contaminants. Mitochondrial proteins from each purification stage are analyzed by quantitative mass spectrometry, and enrichment yields are calculated, allowing the discovery of novel mitochondrial proteins by subtractive proteomics. Our protocol provides a sensitive and comprehensive approach to studying mitochondrial content in cell lines, primary cells, and tissues.

Autor destacado: Aislamiento sin etiquetas en dos pasos de mitocondrias para mejorar el descubrimiento y la cuantificación de proteínas  

We present a two-step protocol for high-quality mitochondria isolation that is compatible with protein discovery and quantification at a proteome scale. Our protocol does not require genetic engineering and is thus suitable for studying mitochondria from any primary cells and tissues.