This work was supported by funding from the National Institutes of Health (R01-DK105346, P41-GM122698, 5U2C-DK119889). A portion of this work was performed in the McKnight Brain Institute at the National High Magnetic Field Laboratory&#39;s Advanced Magnetic Resonance Imaging and Spectroscopy (AMRIS) Facility, which is supported by the National Science Foundation Cooperative Agreement No. DMR-1644779 and the State of Florida.

Experiments involving mice were handled in compliance with the University of Florida Institutional Animal Care and Use Committee (protocol number #201909320). The mouse strain used was C57BL/6J; all mice were male. This method is generally applicable for studies using other standard mouse strains as well. This surgery is optimally performed by two individuals working together.
1. Initial set-up
<ol>
	<li>Perfuse livers with perfusate containing Krebs-Henseleit electrolytes<s...

<ol>
	<li>Ragavan, M., McLeod, M. A., Giacalone, A. G., Merritt, 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=Hyperpolarized+Dihydroxyacetone+Is+a+Sensitive+Probe+of+Hepatic+Gluconeogenic+State.">Hyperpolarized Dihydroxyacetone Is a Sensitive Probe of Hepatic Gluconeogenic State.</a> Metabolites. 11 (7), 441 (2021).</li><li>Lumata, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperpolarized+(13)C+Magnetic+Resonance+and+Its+Use+in+Metabolic+Assessment+of+Cultured+Cells+and+Perfused+Organs.">Hyperpolarized (13)C Magnetic Resonance and Its Use in Metabolic Assessment of Cultured Cells and Perfused Organs.</a> Methods in Enzymology. 561, 561-573 (2015).</li><li>Moreno, K. X., 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=Real-time+detection+of+hepatic+gluconeogenic+and+glycogenolytic+states+using+hyperpolarized+[2-13C]+dihydroxyacetone.">Real-time detection of hepatic gluconeogenic and glycogenolytic states using hyperpolarized [2-13C] dihydroxyacetone.</a> The Journal of Biological Chemistry. 289 (52), 35859-35867 (2014).</li><li>Moreno, K. X., 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=Hyperpolarized+&#948;-[1-13C]+gluconolactone+as+a+probe+of+the+pentose+phosphate+pathway.">Hyperpolarized &#948;-[1-13C] gluconolactone as a probe of the pentose phosphate pathway.</a> NMR in Biomedicine. 30 (6), (2017).</li><li>Merritt, M. E., Harrison, C., Sherry, A. D., Malloy, C. R., Burgess, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flux+through+hepatic+pyruvate+carboxylase+and+phosphoenolpyruvate+carboxykinase+detected+by+hyperpolarized+13C+magnetic+resonance.">Flux through hepatic pyruvate carboxylase and phosphoenolpyruvate carboxykinase detected by hyperpolarized 13C magnetic resonance.</a> Proceedings of the National Academy of Sciences of the United States of America. 108 (47), 19084-19089 (2011).</li><li>Bailey, L. E., Ong, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Krebs-Henseleit+solution+as+a+physiological+buffer+in+perfused+and+superfused+preparations.">Krebs-Henseleit solution as a physiological buffer in perfused and superfused preparations.</a> Journal of Pharmacological Methods. 1 (2), 171-175 (1978).</li><li>Kolwicz, S. C., Tian, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Assessment+of+Cardiac+Function+and+Energetics+in+Isolated+Mouse+Hearts+Using+31P+NMR+Spectroscopy.">Assessment of Cardiac Function and Energetics in Isolated Mouse Hearts Using 31P NMR Spectroscopy.</a> Journal of Visualized Experiments: JoVE. (42), e2069 (2010).</li><li>Hwang, G. 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=Protective+effect+of+butylated+hydroxylanisole+against+hydrogen+peroxide-induced+apoptosis+in+primary+cultured+mouse+hepatocytes.">Protective effect of butylated hydroxylanisole against hydrogen peroxide-induced apoptosis in primary cultured mouse hepatocytes.</a> Journal of Veterinary Science. 16 (1), 17-23 (2015).</li><li>Bessems, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+isolated+perfused+rat+liver:+standardization+of+a+time-honoured+model.">The isolated perfused rat liver: standardization of a time-honoured model.</a> Laboratory Animals. 40 (3), 236-246 (2006).</li><li>Beal, E. W., 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=A+Small+Animal+Model+of+Ex+Vivo+Normothermic+Liver+Perfusion.">A Small Animal Model of Ex Vivo Normothermic Liver Perfusion.</a> Journal of Visualized Experiments: JoVE. (136), e57541 (2018).</li><li>Collins, J. B., Song, J., Mahabir, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Onset+and+duration+of+intradermal+mixtures+of+bupivacaine+and+lidocaine+with+epinephrine.">Onset and duration of intradermal mixtures of bupivacaine and lidocaine with epinephrine.</a> The Canadian Journal of Plastic Surgery. 21 (1), 51-53 (2013).</li><li>. Medical Dictionary Available from: <a target="_blank" href="https://www.merriam-webster.com/medical">https://www.merriam-webster.com/medical</a> (2022)</li><li>Thorpe, D. 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> A Dissection in Color: The Rat (and the Sheep's Brain). , (1968).</li><li>Cabral, 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=Purification+of+Hepatocytes+and+Sinusoidal+Endothelial+Cells+from+Mouse+Liver+Perfusion.">Purification of Hepatocytes and Sinusoidal Endothelial Cells from Mouse Liver Perfusion.</a> Journal of Visualized Experiments: JoVE. (132), e56993 (2018).</li><li>. Operations Manual Setup, Installation and Maintenance Available from: <a target="_blank" href="https://www.chem.ucla.edu/dept/Faculty/merchant/pdf/electrode_prep_maintenance.pdf">https://www.chem.ucla.edu/dept/Faculty/merchant/pdf/electrode_prep_maintenance.pdf</a> (2006)</li><li>. Heparin Available from: <a target="_blank" href="https://go.drugbank.com/drugs/DB01109">https://go.drugbank.com/drugs/DB01109</a> (2022)</li><li>Overmyer, K. A., Thonusin, C., Qi, N. R., Burant, C. F., Evans, C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impact+of+anesthesia+and+euthanasia+on+metabolomics+of+mammalian+tissues:+studies+in+a+C57BL/6J+mouse+model.">Impact of anesthesia and euthanasia on metabolomics of mammalian tissues: studies in a C57BL/6J mouse model.</a> PloS One. 10 (2), 0117232 (2015).</li></ol>

The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

This surgical procedure is challenging and requires extensive practice to achieve reproducible results. Isoflurane and carrier gas should be adjusted as needed to maintain the viability of the animal through as much of the surgical procedure as possible. Environment, time of day, age, weight, and several other factors will affect anesthesia. Weight, diet, strain of mice and age could affect surgery as fat buildup can interfere with visualizing the portal vein. When taping the paws down, care must be taken to not apply an...

Ex vivo perfusions are crucial in the study of hepatic metabolism, and perfusion through the portal vein is the standard for these studies. In order to study hepatic metabolism in isolation, the liver must be resected from the body to avoid complications arising from metabolism in other organs (i.e., whole-body metabolism) and to exert control over hormone availability (insulin, glucagon, etc.). This approach can be essential for understanding the effects of diseases such as diabetes, NAFLD, and NASH on hepatic metabolism as well as mechanisms of drug action. This article serves as a guide to hepatic resection and perfusion. We have developed a streamlined procedure to perform these metabolic liver studies with sufficient rigor and reproducibility. If the surgery is not performed correctly, there is pronounced variability in the metabolic data obtained. We describe an organized method to perform portal vein catheterization and liver resection in the context of metabolic studies in situ in a nuclear magnetic resonance (NMR) spectrometer, as described in the literature1,2,3,4,5.
Currently, there is no literature describing an ex vivo hepatic perfusion using a glass column within an NMR. Nor is there a video or text publication providing a clear example of how to perform the procedure with the mouse liver, specifically, demonstrating how to catheterize the portal vein, resect a liver, transfer, and hang the liver onto a glass column. As the genetically modified mouse is ubiquitously used for studying liver metabolism, this is an essential procedure that deserves a complete description. Liver perfusion surgeries are not new, but this article is a gold standard method accompanied by a video demonstrating the technical excellence described in this paper to aid everyone interested in this procedure. The method presented here would be best applied to real-time metabolism to detect the function and turnover of metabolites in disease models.
This method uses a 100 cm water-jacketed glass column, which allows the liver to hang at the bottom of the cannula encapsulated by perfusate inside an NMR tube. Heated water in the glass jacket is used to control perfusate temperature. A thin layer oxygenator is pressurized with 95%/5% O2/CO2 for pH control. By using three separate pumps, the perfusate column height is set, which provides constant pressure to the liver. Flow rates are not controlled beyond the application of constant pressure (Figure 1). To confirm the liver is appropriately functioning, oxygen measurements are taken along with flow rates. In our hands, this set of preconditions leads to highly repeatable NMR experiments for the assessment of liver metabolic function.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1 mL Luer-Lock Single Use Sterile Disposable Syringe</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Non-specific Brand</td>
		</tr>
		<tr>
			<td>100 cm Water Jacketed Glass Column</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Custom Made</td>
		</tr>
		<tr>
			<td>2-0 Silk Suture</td>
			<td>Braintree Scientific</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>22 Gauge Catherter 1 in. Without Safety</td>
			<td>Terumo</td>
			<td>SRFF2225</td>
			<td></td>
		</tr>
		<tr>
			<td>23 G 0.75 in. Hypodemeric Needles</td>
			<td>Exel International</td>
			<td>26407</td>
			<td></td>
		</tr>
		<tr>
			<td>27 G 1.5 in. Hypodemeric Needles</td>
			<td>Exel International</td>
			<td>26426</td>
			<td></td>
		</tr>
		<tr>
			<td>4x4 in. Surgical Platform</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Custom Made</td>
		</tr>
		<tr>
			<td>70% Alcohol Wipe</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Non-specific Brand</td>
		</tr>
		<tr>
			<td>Circulating Water Bath</td>
			<td>MS Lauda</td>
			<td>N/A</td>
			<td>Model no longer manufactured</td>
		</tr>
		<tr>
			<td>Cotton Tip Applicator</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Non-specific Brand</td>
		</tr>
		<tr>
			<td>Delicate Operating Scissors; Straight; Sharp-Sharp; 30mm Blade Length; 4 3/4 &#34;</td>
			<td>Roboz</td>
			<td>RS-6702</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #5/45 Forceps</td>
			<td>Fine Scientific Tools</td>
			<td>11251-35</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #7 - Fine Forceps</td>
			<td>Fine Scientific Tools</td>
			<td>11274-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemostats</td>
			<td>Fine Scientific Tools</td>
			<td>13015-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Heparin Sodium Injectable 1000 units/mL</td>
			<td>RX Generics</td>
			<td>71288-0402-02</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Patterson Veterinary</td>
			<td>14043-0704-06</td>
			<td></td>
		</tr>
		<tr>
			<td>Lidocaine HCl 2%</td>
			<td>VEDCO Inc.</td>
			<td>50989-0417-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Membrane-Thin-Layer Oxygenator</td>
			<td>Radnoti</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Metzenbaum Scissors; Curved; Blunt; 27 mm Blade Length; 5 &#34;</td>
			<td>Roboz</td>
			<td>RS-6013</td>
			<td></td>
		</tr>
		<tr>
			<td>Oxygen Meter System</td>
			<td>Hanstech Instruments Ltd.</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Saline 0.9% Solution</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Saline is made in lab</td>
		</tr>
		<tr>
			<td>Scale</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Non-specific Brand</td>
		</tr>
		<tr>
			<td>&#160;Variable Speed Analog Console Pump Systems</td>
			<td>Cole Palmer</td>
			<td>N/A</td>
			<td>Models are custom per application</td>
		</tr>
		<tr>
			<td>Weigh boats</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Non-specific Brand</td>
		</tr>
	</tbody>
</table>

ex vivo hepatic perfusion through the portal vein in mouse

Metabolic diseases such as diabetes, pre-diabetes, non-alcoholic fatty liver disease (NAFLD), and nonalcoholic steatohepatitis (NASH) are becoming increasingly common. Ex vivo liver perfusions allow for a comprehensive analysis of liver metabolism using nuclear magnetic resonance (NMR), in nutritional conditions that can be rigorously controlled. As in silico simulations remain a primarily theoretical means of assessing hormone actions and the effects of pharmaceutical intervention, the perfused liver remains one of the most valuable test beds for understanding hepatic metabolism. As these studies guide basic insights into hepatic physiology, results must be accurate and reproducible. The greatest factor in the reproducibility of ex vivo hepatic perfusion is the quality of surgery. Therefore, we have introduced an organized and streamlined method to perform ex vivo mouse liver perfusions in the context of in situ NMR experiments. We also describe a unique application and discuss common issues encountered in these studies. The overall purpose is to provide an uncomplicated guide to a technique we have refined over several years that we deem the golden standard for obtaining reproducible results in hepatic resections and perfusions in the context of in situ NMR experiments. The distance to the center of the field for the magnet as well as the inaccessibility of the tissue to intervention during the NMR experiment makes our methods novel.

Liver function is primarily assessed by oxygen consumption and flow rate. A flow rate of 4-8 mL/min and oxygen consumption of 1 &#181;mol/min.g is typical. These measures will vary depending on specific experimental conditions and biological differences.
The exact amount of isoflurane used will depend on the type of anesthesia system being used as well as the environment and age/weight of the mouse. During the surgery, the isoflurane and delivery gas do not change, although some changes may be...

Watch this Scientific Journal Video about Ex Vivo Hepatic Perfusion Through the Portal Vein in Mouse at JoVE.com

Ex Vivo Hepatic Perfusion Through the Portal Vein in Mouse

The protocol describes a straightforward method of resectioning an intact mouse liver for metabolic studies through portal vein perfusion.

Ex Vivo Hepatic Perfusion Through the Portal Vein in Mouse

Metabolic diseases such as diabetes, pre-diabetes, non-alcoholic fatty liver disease (NAFLD), and nonalcoholic steatohepatitis (NASH) are becoming ...

This video demonstrates a streamlined procedure developed to perform metabolic liver studies with sufficient rigor and reproducibility, which can serve as a guide to perform hepatic resection for its vivo perfusion studies. The technique is best applied to real-time metabolism to detect the function, in turnover metabolites in disease models. Perfusion allows precise control of nutrients and hormones available to the liver.Although the technique is not directed towards therapy, liver perfusions can be instrumental in understanding the etiology and impact of diseases, such as diabetes, NAFLD, and NASH on hepatic metabolism. As new pharmaceuticals are developed, methods for assessing hepatic central energy metabolism become essential. This method can be used with models of several diseases, including cancers and at several different stages of disease progression.To begin with, place the nose of the mouse into a nose cone after the induction of anesthesia, and taped down its paws. Administer lidocaine through a subcutaneous injection bilaterally in the anterior iliac crest region. Perform a toe pinch test to confirm the absence of all pain reflexes.Perform celiotomy to expose the internal organs by making a three centimeter wide incision. Expand the incision using a hemostat that pulls the traction by clamping on the xiphoid process. Use a cotton tipped applicator to clear the small and large intestines covering the portal vein.Position a silk suture under the arch of the portal vein proximal to the liver. Place the second silk suture proximal or distal of the inferior mesenteric vein distal from the liver using a 2-0 suture. Once the sutures are in place, cannulate the portal vein with a 22 gauge catheter, keeping the bevel pointing up.Enter the portal vein at no more than a 15 degree angle. Tie the first suture past the catheter tapper. After the portal vein is cannulated, anchor the catheter two to three millimeter distal from the branch of the portal vein with the silk suture.Secure the lower portion of the catheter with the second suture. Tie a knot with the suture to secure the catheter to the distal portion of the portal vein and the surrounding tissue. After the catheter is secured, insert a one milliliter syringe with a 27 gauge needle having 38.1 millimeters length into the catheter to flush blood and air bubbles.Use a one millimeter inner diameter and five millimeter outer diameter silicone tube with a fixed stop cock to couple the perfusion column to the catheter, allowing the flow of the buffer into the liver, marking the start of the perfusion. After starting a timer, relieve increased vascular pressure by incision using scissors into the inferior vena cava. Confirm flow of perfusate through the liver by observing the homogenous change in liver color from pink or red to a pale yellow.Once the flow is confirmed, excise the stomach, small intestine, large intestine, and the right kidney from surrounding tissue. With the help of the surgical assistant, maneuver the liver around the abdominal and thoracic cavity as the surgeon cuts through the parietal peritoneum and thoracic tissue to resect the liver. Lift the liver upwards and cut the remaining connective tissues holding the liver in place with scissors.Slowly manipulate the liver for ease of view. The flow rate and oxygen consumption measurements are vital to monitoring the liver's health and function. There is often a slight difference in oxygen consumption between fed and fasted livers, which can be attributed to increased energy demands imposed by glucogenesis in the fasted liver.The most important steps include inserting the catheter at a 15 degree angle, visualizing the catheter tip, rolling the wrist and shoulders when tying the suture, and avoiding torsion on the portal vein. The excised tissue can be studied after the perfusion with any number of biochemical or analytical approaches. Ex vivo perfusions in combination with real-time MRI and spectroscopy enable the measurement of metabolic fluxes in real-time.Naturally, this extends to perturbation of flux from a control state in response to the diseases.

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JoVE Journal

Biochemistry

7.9K vues.  University of Florida. Cette vidéo démontre une procédure simplifiée développée pour effectuer des études métaboliques du foie avec suffisamment de rigueur et de reproductibilité, qui peut servir de guide pour effectuer une résection hépatique pour ses études de perfusion vivo. La technique est mieux appliquée au métabolisme en temps réel pour détecter la fonction, dans les métabolites du chiffre d’affaires dans les modèles de maladie. La perfusion permet un contrôle précis des nutriments et d...