This work was made possible by the Human Tissue and Cell Research Foundation, which makes human tissues available for research. Financial support for this work was received from the Federal Ministry of Education and Research (grant name: Virtual Liver Network, grant number: 0315759) and Hepacult GmbH. Our thanks also go to the technical assistants from the Grosshadern Hospital Tissue bank for the collection of the liver samples and the technical assistants from the Cell Isolation Core Facility for carrying out the liver perfusion and hepatocyte isolation. In particular, we would like to thank Natalja L&ouml;wen for demonstrating this procedure in the video. Finally, we would like to thank Natalja L&ouml;wen and Edeltraud Hanesch for creating the illustrations for Figure 1 and the figures in the schematic overview of the video.

1. Preparation of Perfusion and Isolation Solutions
<ol>
	<li>Prepare the solutions required for the perfusion of the liver piece and the isolation of hepatocytes according to Table 1. Solutions can be stored at 4 &deg;C until use.</li>
	<li>Sterile filter all solutions using a 0.22 &mu;m filter.</li>
	<li>All solutions that come into contact with the liver should be sterile.</li>
</ol>
2. Preparation of Perfusion Equipment and Solutions
<ol>
	<li>The equipment for the perfusion of the liver piece should be set up as shown in Figure 1.</li>
	<li>The water bath should be set at an appropriate temperature, which is different in each particular experimental set-up, such that the solutions are at the temperature of 37 &deg;C when they reach the liver piece. In this case, the water bath is set at 41 &deg;C to warm the Solutions 1, 2 and 3 and the jacketed glass condenser. Solution 4 should be warmed up to 37 &deg;C in a separate water bath for use to reduce the loss of collagenase activity.</li>
	<li>Shortly before liver perfusion, turn on the regulator of the gas tank containing 95% O2/5% CO2 to gas the oxygenation apparatus (Figure 1E).</li>
</ol>
3. Perfusion of the Liver
<ol>
	<li>A liver piece with as much intact Glisson's capsule as possible and ideally with only 1 cut surface should be obtained from a pathologist for perfusion.</li>
	<li>Place this liver piece on the B&uuml;chner funnel that contains a perforated filter disc (Figure 1B).</li>
	<li>The perfusion system should be primed with Solution 1.</li>
	<li>With a low flow rate, curved irrigation cannulae with olive tips should be inserted into the larger blood vessels on the cut surface of the liver piece. As blood flushes out from the liver, the tissue becomes lighter in areas with good perfusion. The number of cannulae used for various sizes of livers is shown in Figure 2A. The gauge size chosen should result in a snug fit that will hold the cannulae in place. The smaller blood vessels should be left open for the perfusion buffer to drain out of the liver piece.</li>
	<li>Increase the flow rate on the peristaltic pump to between 110-460 ml/min depending on the size of the liver (Figure 2B). This results in an average flow rate of 44&plusmn;16 ml/min per cannula (Figure 2C). The speed chosen depends on the liver piece and should result in a slight plumping up of the liver piece. In some cases, it may be necessary to clamp shut some of the open vessels with micro vascular clamps to achieve the slight plumping mentioned above. A good perfusion can be observed when the liver piece is a lighter color throughout.</li>
	<li>Keep the liver piece moist during perfusion by covering it with a piece of gauze soaked in saline.</li>
	<li>Perfuse with 1 L of Solution 1 to flush out any remaining blood in the liver piece.</li>
	<li>Change the perfusion fluid to Solution 2 and perfuse for 10 min.</li>
	<li>Switch the perfusion fluid to Solution 3 and perfuse with 0.5 L.</li>
	<li>Change the perfusion fluid to Solution 4, which contains 0.1-0.15% of collagenase (Table 2).</li>
	<li>For this step, perfusion should be carried out in a recirculating manner for 9-12 min or until the liver is sufficiently digested; the liver tissue should appear to break apart slightly under the Glisson's capsule and feel softened when probed with the blunt side of a scalpel.</li>
</ol>
4. Isolation of Hepatocytes
<ol>
	<li>Turn off the peristaltic pump and remove cannulae from the liver piece.</li>
	<li>Place the liver piece in a crystallizing dish containing 100-200 ml of Solution 5.</li>
	<li>Remove the Glisson's capsule carefully and gently shake out the cells. If there are regions that are not well perfused, a scalpel can be used to cut through these regions to release cells contained within. Add more Solution 5 as needed during the process.</li>
	<li>Add more Solution 5 until a final volume of 500 ml is reached.</li>
	<li>Filter cell suspension twice; first through a 210 &mu;m nylon mesh followed by a 70 &mu;m nylon mesh. Next, pour the cell suspension into 200 ml centrifuge tubes.</li>
	<li>Centrifuge the cell suspension at 72 g for 5 min at 4 &deg;C. Aspirate supernatant and gently resuspend cell pellet gently in 200 ml of Solution 5.</li>
	<li>Repeat the washing step number 4.6 three times. On the final centrifuge step, resuspend cells in cold storage solution (see list of materials). Cells should be approximately 2-5 million hepatocytes per milliliter for assessment of yield and viability using a hemocytometer-based trypan blue exclusion assay.</li>
	<li>To carry out a trypan blue exclusion assay, add 0.1 ml of appropriately diluted cells (&asymp;2-5 million/ml) to a microfuge tube containing 0.5 ml of trypan blue solution (0.4% trypan blue dissolved in phosphate-buffered saline (PBS)) and 0.4 ml of PBS. After mixing the cell suspension thoroughly, load a hemocytometer with the suspension and examine under a microscope at 100X magnification. Under microscopy, the dead cells will be stained blue while the live cells appear unstained. Count the number of live and total cells in each of the 1 mm2 grids marked on the hemocytometer. Viability (%), yield of live cells (million hepatocytes per ml cold storage solution (CSS) or million hepatocytes per g liver) can be calculated using the formulae below.</li>
</ol>
<img alt="Equation 1" fo:src="/files/ftp_upload/50615/50615eq1highres.jpg" src="/files/ftp_upload/50615/50615eq1.jpg" /> 
Note: In this case, the trypan blue dilution factor is 10 and the hemocytometer factor is 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. 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Optimization of this protocol was partially funded by a grant from Hepacult GmbH. Dr. Wolfgang Thasler is one of the founders of Hepacult GmbH and remains one of the members of the board in this company. The employment of Maresa Demmel is partially by Hepacult. Maria Hauner is employed by Hepacult GmbH. Hepacult is a spin-off biotechnological firm from the University, which offers human hepatocytes with consent and open access for research purposes.

This protocol results in the isolation of human hepatocytes with high viability and purity. In order to achieve these results, it is important to start with a suitable piece of liver. The piece of liver should have intact Glisson's capsule on all surfaces except for 1 cut surface. Another important factor is the particular batch of collagenase used, as different batches can result in marked differences in viabilities of hepatocytes after digestion 11. Therefore, different batches of collagenase should be teste...

A correction was made to: <a href="https://www-jove-com.remotexs.ntu.edu.sg/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

A liver cell suspension can be prepared from the liver by mechanical or enzymatic methods. Mechanical methods used to prepare whole liver cells include forcing the liver through cheesecloth 2, shaking a liver piece with glass beads in a Kahn shaker 3, using glass homogenizers with loose pestles 4,5 etc. Over the years, mechanical methods have fallen out of favor due to the damage to cell membranes and the loss of function of the isolated hepatocytes 6,7. Consequently, the use of an enzymatic method is currently the main method for isolation of hepatocytes.
Isolation of hepatocytes using an enzymatic method was greatly improved when Berry and Friend 8 perfused collagenase and hyaluronidase through the liver via the portal vein in rats. This perfusion process utilized the vasculature to allow the enzymes to come into close contact with the majority of the cells, leading to a 6-fold increase in yield of hepatocytes 8. Further, this method yielded cells that retained their structural integrity, with virtually no transformation of endoplasmic reticulum into isolated vesicles and no mitochondrial damage 8.
This method was modified by Seglen 1, who pioneered a two-step perfusion procedure for liver cell isolation. In this procedure, the rat liver is perfused with a Ca2+ free buffer followed by perfusion with a collagenase buffer containing Ca2+ 1. The removal of Ca2+ in the first step helps to disrupt desmosomes, while the addition of Ca2+ in the second step is required for optimum collagenase activity 1,9.
Given that the published work described above has been performed in rats, this article aims to demonstrate a modified procedure that can be used for isolation of hepatocytes with high viability from human livers. The use of human hepatocytes remains important for translational research and for validating experiments using animal models. The human liver pieces used in this study were acquired with consent for governance through the Human Tissue and Cell Research Foundation, a state-controlled non-profit foundation 10. After a pathologist removed what was required for diagnosis, liver pieces were collected from the remaining tissue. The tissue sectioned off by the pathologist was morphologically healthy tissue obtained from resection margins after liver resection.

<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

The liver, an organ with an exceptional regeneration capacity, carries out a wide range of functions, such as detoxification, metabolism and homeostasis. As such, hepatocytes are an important model for a large variety of research questions. In particular, the use of human hepatocytes is especially important in the fields of pharmacokinetics, toxicology, liver regeneration and translational research. Thus, this method presents a modified version of a two-step collagenase perfusion procedure to isolate hepatocytes as described by Seglen 1.
Previously, hepatocytes have been isolated by mechanical methods. However, enzymatic methods have been shown to be superior as hepatocytes retain their structural integrity and function after isolation. This method presented here adapts the method designed previously for rat livers to human liver pieces and results in a large yield of hepatocytes with a viability of 77&plusmn;10%. The main difference in this procedure is the process of cannulization of the blood vessels. Further, the method described here can also be applied to livers from other species with comparable liver or blood vessel sizes.

Perfusion Setup
The equipment required for liver perfusion should be set up according to Figure 1.
Viability and Yield of Isolated Human Hepatocytes
The average viability of isolated human hepatocytes was 77&#177;10% and the average yield of hepatocytes was 13&#177;11 million hepatocytes/g liver, with values expressed as means &#177; standard deviation. The number of hepatocyte isolations carried out to obtain these averages wa...

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

A modified two-step collagenase perfusion procedure for isolation of human hepatocytes is described. This method can also be applied to other mammalian livers. The isolated hepatocytes are available in high yield and viability, making them a suitable model for scientific research in areas such as liver regeneration, pharmacokinetics and toxicology.

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

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30.9K Views.  Grosshadern Hospital, Munich. A modified two-step collagenase perfusion procedure for isolation of human hepatocytes is described. This method can also be applied to other mammalian livers. The isolated hepatocytes are available in high yield and viability, making them a suitable model for scientific research in areas such as liver regeneration, pharmacokinetics and toxicology.

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.

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 ...

In vivo Liver Endocytosis Followed by Purification of Liver Cells by Liver Perfusion

The liver is the metabolic center of the mammalian body and serves as a filter for the blood. The basic architecture of the liver is illustrated in figure 1 in which more than 85% of the liver mass is composed of hepatocytes and the remaining 15% of the cellular mass is composed of Kupffer cells (KCs), stellate cells (HSCs), and sinusoidal endothelial cells (SECs). SECs form the blood vessel walls within the liver and contain specialized morphology called fenestrae within in the cytoplasm. Fenestration of the cytoplasm is the appearance of holes (&tilde;100 &mu;m) within the cells so that the SECs act as a sieve in which most chylomicrons, chylomicron remnants and macromolecules, but not cells, pass through to the hepatocytes and HSCs 1 (Fig. 1). Due to the lack of a basement membrane, the gap between the SECs and hepatocytes form the Space of Disse. HSCs occupy this space and play a prominent role in regulation and response to injury, storage of retinoic acid and immunoregulation of the liver 2.
SECs are among the most endocytically active cells of the body displaying an array of scavenger receptors on their cell surface 3. These include SR-A, Stabilin-1 and Stabilin-2. Generally, small colloidal particles less than 230 nm and macromolecules in buffer phase are taken up by SECs, whereas, large particles and cellular debris is endocytosed (phagocytosed) by KCs 4. Thus, the bulk clearance of extracellular material such as the glycosaminoglycans from blood is largely dependent on the health and endocytic functions of SECs 5,6. For example, an increase in blood hyaluronan levels is indicative of liver disease ranging from mild to more severe forms 7.
With the exception of one report 8, there are no immortalized SEC cell lines in existence. Even this immortalized cell line is de-differentiated in that it does not express scavenger receptors that are present on primary SECs (our data, not shown). All cell biological studies must be performed on primary cells obtained freshly from the animal. Unfortunately, SECs dedifferentiate under standard culture conditions and must be used within 1 or 2 days upon isolation from the animal. Differentiation of SECs is marked by the expression of Stabilin-2 or HARE receptor 9 , CD31, and the presence of cytoplasmic fenestration 1. Differentiation of SECs can be extended by the addition of VEGF in culture media or by culturing cells in hepatocyte conditioned medium 10,11.
In this report, we will demonstrate the endocytic activity of SECs in the intact organ using radio-labeled heparin for hyaluronan for the SEC-specific Stabilin-2 receptor. We will then purify hepatocytes and SECs from the perfused liver to measure endocytosis.

In vivo Liver Endocytosis Followed by Purification of Liver Cells by Liver Perfusion

The study of liver sinusoidal endothelial cells (SECs) must be performed with primary cells obtained from the animal as no cell lines exist. This method relies on liver digestion and differential centrifugation for SEC purification for subsequent culturing and experimentation.

The liver is the metabolic center of the mammalian body and serves as a filter for the blood.  The basic architecture of the liver is illustrated in ...

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.

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.

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.

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.

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

Isolation of Primary Myofibroblasts from Mouse and Human Colon Tissue

The myofibroblast is a stromal cell of the gastrointestinal (GI) tract that has been gaining considerable attention for its critical role in many GI functions. While several myofibroblast cell lines are commercially available to study these cells in vitro, research results from a cell line exposed to experimental cell culture conditions have inherent limitations due to the overly reductionist nature of the work. Use of primary myofibroblasts offers a great advantage in terms of confirming experimental findings identified in a cell line. Isolation of primary myofibroblasts from an animal model allows for the study of myofibroblasts under conditions that more closely mimic the disease state being studied. Isolation of primary myofibroblasts from human colon tissue provides arguably the most relevant experimental data, since the cells come directly from patients with the underlying disease. We describe a well-established technique that can be utilized to isolate primary myofibroblasts from both mouse and human colon tissue. These isolated cells have been characterized to be alpha-smooth muscle actin and vimentin-positive, and desmin-negative, consistent with subepithelial intestinal myofibroblasts. Primary myofibroblast cells can be grown in cell culture and used for experimental purposes over a limited number of passages.

The myofibroblast is an influential stromal cell of the gastrointestinal tract that regulates important physiologic processes in both normal and disease states. We describe a technique that allows for the isolation of primary myofibroblasts from both mouse and human colon tissue, which can be utilized for in vitro experimentation.

The myofibroblast is  a stromal cell of the gastrointestinal (GI) tract that has been gaining  considerable attention for its critical role in many GI ...

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.

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.

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.

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