The authors would like to thank Jens Geiling from the Institute of Anatomy I, Jena University Hospital, for producing the schematic drawings of rat liver anatomy.

The housing and all procedures carried out were in accordance with German animal welfare legislation. All gauze, covering clothes, and surgical instruments are autoclaved and prepared before the operation. All procedures are carried out under sterile conditions.
1. Preparation of the Rat for the Surgical Procedure
<ol>
	<li>Place the rat in an induction chamber and anesthetize the rat with 4% vaporized isoflurane and 100% oxygen at 0.5 L/min for about 3 min, until the rat is completely anesthetized.</li>
	<li>Take the rat out of the induction chamber and measure its body weight.</li>
	<li>Shave the fur of the surgical region on the abdomen.</li>
	<li>Place the animal back into the isoflurane chamber for an additional 2 min to deepen anesthesia.</li>
	<li>Place the rat on the operation table in supine position.</li>
	<li>Fix the anesthesia mask to the mouth region of the rat and keep the animal anesthetized with a continuous gas flow of 2% vaporized isoflurane and 100% oxygen at a flow rate of 0.5 L/min.</li>
	<li>Fix the limbs with pieces of tape.</li>
	<li>Apply vet ointment on both eyes to prevent dryness.</li>
	<li>Administer buprenorphine 0.05 mg/kg subcutaneously, to relieve pain during the operation period.</li>
	<li>Disinfect the surgical field of the abdomen with 3 rounds of iodine tincture followed by 2 rounds of 70% alcohol.</li>
	<li>Place sterilized gauze around the area where the incision will be made to only leave the operation field of the abdomen exposed.</li>
	<li>Proceed to perform the operation when the toe-pinch withdrawal reflex of the rat is absent.</li>
</ol>
2. Laparotomy of the Rat
<ol>
	<li>Make a transverse abdominal skin and muscle incision using scissors and an electrical coagulator.</li>
	<li>Fix and pull the xiphoid process toward the head using a 4-0 polypropylene suture. 
	NOTE: Pay attention to lift up the xiphoid process vertically to better expose the liver, but proceed with caution to avoid severe respiratory restriction and suffocation.</li>
	<li>Open the peritoneal cavity by pulling both sides of the abdominal walls towards the head with two subcostal hooks to expose the liver.</li>
	<li>Cover the duodenum and small intestine in the abdominal cavity with a moistened gauze to avoid drying.</li>
	<li>Lift left and right median lobes up by using a moistened gauze and hold them against the thorax to better expose the hilum of the liver.</li>
	<li>Place the rat under a stereomicroscope (8X magnification).</li>
	<li>Drop some warm saline into the abdomen and onto the surface of the liver and intestines every several minutes, to prevent drying during the whole procedure.</li>
</ol>
3. Establishment of a Bypass Passage Within the Left Lateral Lobe
<ol>
	<li>Dissect the left portal vein and ligate it with a 6-0 silk suture at the base (Figure 2A).</li>
	<li>Block the left hepatic artery, the left bile duct along with the left median portal vein, the left median hepatic artery, and the left median bile duct with micro clamps to prevent a flow of the perfusate to the left median lobe (Figure 2B).</li>
	<li>Separate the left lateral lobe by cutting off the surrounding ligaments of the lobe with micro scissors.</li>
	<li>Block the left lateral hepatic vein by clamping at the base of the left lateral lobe with micro clamps (Figure 2C). 
	NOTE: Make sure not to clamp the left portal vein as well by mistake.</li>
	<li>Use mosquito clamps to hold the ligature of the left portal vein and keep the vein with proper tension for later cannulation.</li>
	<li>Carefully make an incision in the front wall of the left portal vein by puncturing it with a 24-G needle-dwelling catheter ( Figure 3A). 
	NOTE: To create a bypass, vascular access points on the left portal vein and the left hepatic vein are needed. For this step, it is preferred to create the vascular access by puncturing the vessels with a needle rather than making a larger incision using scissors. This reduces the risk of bleeding and later stenosis.</li>
	<li>Withdraw the catheter and take the needle out of the catheter to obtain a needle-free 24-G catheter.</li>
	<li>Connect the catheter to a perfusion tube, of which the other endpoint connects to a 20-mL syringe with 15 mL of 40 U/mL heparinized saline on a perfusion pump.</li>
	<li>Turn on the pump for perfusing the tube to expel air out from the tube and the needle-free catheter.</li>
	<li>Turn off the perfusion pump.</li>
	<li>Again, insert the needle-free catheter into the left portal vein via the punctured incision on the vein (Figure 3B). 
	NOTE: Owing to the fact there is very limited space for fixing the catheter, it is not fixed at this point. Therefore, the surgeon should use care to avoid the displacement of the cannulated catheter.</li>
	<li>Carefully make another incision at the margin of the exposed region of the left lateral hepatic vein by puncturing it with a 22- or 24-G needle-dwelling catheter (Figure 3C). 
	NOTE: It is recommended that the catheter be slightly smaller than the vessel.</li>
	<li>Withdraw the catheter and take the needle out of the catheter to obtain a needle-free 22-G catheter.</li>
	<li>Turn on the perfusion pump to perfuse heparinized saline into the left lateral lobe via the 24-G cannulated needle-free catheter of the left portal vein at a flow rate of 0.5 mL/min.</li>
	<li>Use dry gauze to absorb out-flowing waste fluid around the incision area of the left lateral hepatic vein.</li>
	<li>Cannulate the left lateral hepatic vein via the punctured incision of the vein with the 22-G needle-free catheter, to generate a fluid outlet to minimize intra-abdominal contamination (Figure 3D). 
	NOTE: It is technically difficult to fix the cannulated catheter to the liver lobe. Therefore, the surgeon should pay attention to avoid displacement of the catheter. Alternatively, without cannulation of the left lateral hepatic vein with a catheter, waste fluid can also be absorbed at the incision region of the vein only with a dry gauze.</li>
	<li>Keep perfusing the left lateral lobe with heparinized saline for around 20 min (group 1) and then only with saline for 2 h, 3 h, or 4 h (group 2, group 3, and group 4, respectively).</li>
	<li>Turn off the pump to stop the perfusion.</li>
</ol>
4. Physiological Reperfusion of the Left Lateral Lobe
<ol>
	<li>Take off both catheters from the left portal vein and the left lateral hepatic vein.</li>
	<li>Close the incision of the left portal vein with an 11-0 polyamide suture.</li>
	<li>Close the incision of the left lateral hepatic vein with an 11-0 polyamide suture as well.</li>
	<li>Unclamp the left lateral hepatic vein.</li>
	<li>Unclamp the left median portal vein, left bile duct, and left hepatic artery.</li>
	<li>Cut off the ligature on the left portal vein to reopen the vein.</li>
</ol>
5. Closure of the Abdominal Wall
<ol>
	<li>Close the muscle layer of the abdominal wall by interrupted suturing with a 4-0 absorbable polyglactin 910 suture.</li>
	<li>Close the skin layer of the abdominal wall by interrupted suturing with a 4-0 absorbable polydioxanone suture.</li>
	<li>After closing the abdomen, disinfect the skin incision with 70% alcohol.</li>
</ol>
6. Postoperative Treatment of the Rat
<ol>
	<li>Place the animal on a warming pad for resuscitation for about 10 min and then put it into a new cage.</li>
	<li>Administer buprenorphine 0.05 mg/kg subcutaneously 2x a day for a consecutive 3 d postoperatively to release pain.</li>
</ol>

<ol>
	<li>Kim, W. R., 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=OPTN+/+SRTR+2016+Annula+Data+Report:+Liver.">OPTN / SRTR 2016 Annula Data Report: Liver.</a> American Journal of Transplantation. Suppl. 1, 172-253 (2018).</li><li>Palakkan, A. A., Hay, D. C., Anil Kumar, P. R., Kumary, T. V., Ross, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liver+tissue+engineering+and+cell+sources:+issues+and+challenges.">Liver tissue engineering and cell sources: issues and challenges.</a> Liver International. 33, 666-676 (2013).</li><li>Hynes, R. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+extracellular+matrix:+not+just+pretty+fibrils.">The extracellular matrix: not just pretty fibrils.</a> Science. 326, 1216-1219 (2009).</li><li>Flaim, C. J., Chien, S., Bhatia, S. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+extracellular+matrix+microarray+for+probing+cellular+differentiation.">An extracellular matrix microarray for probing cellular differentiation.</a> Nature Methods. 2, 119-125 (2005).</li><li>Wells, R. 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+role+of+matrix+stiffness+in+regulating+cell+behavior.">The role of matrix stiffness in regulating cell behavior.</a> Hepatology. 47, 1394-1400 (2008).</li><li>Ren, 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=Evaluation+of+two+decellularization+methods+in+the+development+of+a+whole-organ+decellularized+rat+liver+scaffold.">Evaluation of two decellularization methods in the development of a whole-organ decellularized rat liver scaffold.</a> Liver International. 33, 448-458 (2013).</li><li>Yagi, 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=Human-scale+whole-organ+bioengineering+for+liver+transplantation:+a+regenerative+medicine+approach.">Human-scale whole-organ bioengineering for liver transplantation: a regenerative medicine approach.</a> Cell Transplantation. 22, 231-242 (2013).</li><li>Jiang, W. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cryo-chemical+decellularization+of+the+whole+liver+for+mesenchymal+stem+cells-based+functional+hepatic+tissue+engineering.">Cryo-chemical decellularization of the whole liver for mesenchymal stem cells-based functional hepatic tissue engineering.</a> Biomaterials. 35, 3607-3617 (2014).</li><li>Uygun, B. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organ+reengineering+through+development+of+a+transplantable+recellularized+liver+graft+using+decellularized+liver+matrix.">Organ reengineering through development of a transplantable recellularized liver graft using decellularized liver matrix.</a> Nature Medicine. 16, 814-820 (2010).</li><li>Baptista, P. 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+use+of+whole+organ+decellularization+for+the+generation+of+a+vascularized+liver+organoid.">The use of whole organ decellularization for the generation of a vascularized liver organoid.</a> Hepatology. 53, 604-617 (2011).</li><li>Bruinsma, B. G., Kim, Y., Berendsen, T. A., Yarmush, M. L., Uygun, B. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Layer-by-layer+heparinization+of+decellularized+liver+matrices+to+reduce+thrombogenicity+of+tissue+engineered+grafts.">Layer-by-layer heparinization of decellularized liver matrices to reduce thrombogenicity of tissue engineered grafts.</a> Journal of Clinical and Translational Research. 1 (1), (2015).</li><li>Park, K. 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=Decellularized+Liver+Extracellular+Matrix+as+Promising+Tools+for+Transplantable+Bioengineered+Liver+Promotes+Hepatic+Lineage+Commitments+of+Induced+Pluripotent+Stem+Cells.">Decellularized Liver Extracellular Matrix as Promising Tools for Transplantable Bioengineered Liver Promotes Hepatic Lineage Commitments of Induced Pluripotent Stem Cells.</a> Tissue Engineering Part A. 22, 449-460 (2014).</li><li>Ko, I. K., 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=Bioengineered+transplantable+porcine+livers+with+re-endothelialized+vasculature.">Bioengineered transplantable porcine livers with re-endothelialized vasculature.</a> Biomaterials. 40, 72-79 (2015).</li><li>Bao, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Construction+of+a+portal+implantable+functional+tissue-engineered+liver+using+perfusion-decellularized+matrix+and+hepatocytes+in+rats.">Construction of a portal implantable functional tissue-engineered liver using perfusion-decellularized matrix and hepatocytes in rats.</a> Cell Transplantation. 20, 753-766 (2011).</li><li>Pan, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-vivo+organ+engineering:+Perfusion+of+hepatocytes+in+a+single+liver+lobe+scaffold+of+living+rats.">In-vivo organ engineering: Perfusion of hepatocytes in a single liver lobe scaffold of living rats.</a> The International Journal of Biochemistry &amp; Cell Biology. 80, 124-131 (2016).</li><li>Madrahimov, N., 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=Marginal+hepatectomy+in+the+rat:+from+anatomy+to+surgery.">Marginal hepatectomy in the rat: from anatomy to surgery.</a> Annals of Surgery. 244, 89-98 (2006).</li><li>Mussbach, F., Settmacher, U., Dirsch, O., Dahmen, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bioengineered+Livers:+A+New+Tool+for+Drug+Testing+and+a+Promising+Solution+to+Meet+the+Growing+Demand+for+Donor+Organs.">Bioengineered Livers: A New Tool for Drug Testing and a Promising Solution to Meet the Growing Demand for Donor Organs.</a> European Surgical Research. 57, 224-239 (2016).</li><li>Mussbach, F., Settmacher, U., Dirsch, O., Dahmen, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liver+engineering+as+a+new+source+of+donor+organs:+A+systematic+review.">Liver engineering as a new source of donor organs: A systematic review.</a> Der Chirurg. 87, 504-513 (2016).</li><li>Xie, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monitoring+of+systemic+and+hepatic+hemodynamic+parameters+in+mice.">Monitoring of systemic and hepatic hemodynamic parameters in mice.</a> Journal of Visualized Experiments. (92), e51955 (2014).</li><li>Zhou, 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=Decellularization+and+Recellularization+of+Rat+Livers+With+Hepatocytes+and+Endothelial+Progenitor+Cells.">Decellularization and Recellularization of Rat Livers With Hepatocytes and Endothelial Progenitor Cells.</a> Artificial Organs. 40, E25-E38 (2016).</li><li>Yagi, 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=Human-scale+whole-organ+bioengineering+for+liver+transplantation:+a+regenerative+medicine+approach.">Human-scale whole-organ bioengineering for liver transplantation: a regenerative medicine approach.</a> Cell Transplantation. 22, 231-242 (2013).</li><li>Otsuka, H., Sasaki, K., Okimura, S., Nagamura, M., Nakasone, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Micropatterned+co-culture+of+hepatocyte+spheroids+layered+on+non-parenchymal+cells+to+understand+heterotypic+cellular+interactions.">Micropatterned co-culture of hepatocyte spheroids layered on non-parenchymal cells to understand heterotypic cellular interactions.</a> Science and Technology of Advanced Materials. 14, 065003 (2013).</li><li>Bale, S. S., 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=Long-term+coculture+strategies+for+primary+hepatocytes+and+liver+sinusoidal+endothelial+cells.">Long-term coculture strategies for primary hepatocytes and liver sinusoidal endothelial cells.</a> Tissue Engineering Part C: Methods. 21, 413-422 (2015).</li><li>Wu, Q., 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=Optimizing+perfusion-decellularization+methods+of+porcine+livers+for+clinical-scale+whole-organ+bioengineering.">Optimizing perfusion-decellularization methods of porcine livers for clinical-scale whole-organ bioengineering.</a> BioMed Research International. , 785474 (2015).</li><li>Barakat, O., 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=Use+of+decellularized+porcine+liver+for+engineering+humanized+liver+organ.">Use of decellularized porcine liver for engineering humanized liver organ.</a> Journal of Surgical Research. 173 (1), e11-e25 (2012).</li><li>Navarro-Tableros, V., 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=Recellularization+of+rat+liver+scaffolds+by+human+liver+stem+cells.">Recellularization of rat liver scaffolds by human liver stem cells.</a> Tissue Engineering Part A. 21 (11-12), 1929-1939 (2015).</li></ol>

The authors have nothing to disclose.

By blocking and cannulating the left portal vein with a catheter as a fluid inlet and the left lateral hepatic vein with another catheter as a fluid outlet, we successfully generated an in vivo fluid bypass within the left lateral lobe, indicating that although the technique is highly challenging due to the small size of the vessels for cannulation and a high risk of causing bleeding, it is feasible. Even the rats undergoing a long perfusion period of 4 hours survived at least 1 week, showing that the rats could...

The indications for organ transplantation are constantly expanding. In contrast, organ donation rates and overall quality of organs are declining, leading to an increasing demand for grafts. The number of candidates added to the liver transplant waiting list continued to increase (e.g., in the United States, 11,340 patients were added in 2016, compared with 10,636 in 2015)1. Despite substantial efforts, the number of available organs does not meet clinical needs. Due to the increased incidence of liver disease, many patients with end-stage liver diseases die on the transplant waiting list before a donor organ becomes available. To meet the huge demand for donor liver grafts, alternative approaches using liver tissue engineering principles are being actively pursued2. Nowadays, a newly developed biological technique of liver engineering could potentially overcome this shortage.
Liver engineering consists of two steps: the generation of an acellular scaffold, followed by a repopulation of the scaffold. To obtain a biological acellular liver scaffold, the explanted liver is perfused via the vascular system with ionic or nonionic detergents, which can remove the cellular material from the liver. In most previous studies, a biological acellular liver scaffold was achieved by perfusion of the liver with a combination of sodium dodecyl sulfate and TritonX100. As a result, all cells were removed, whereas the structure of the extracellular matrix was maintained. The organ scaffolds were reseeded with mature cells, hepatocellular, as well as endothelial cell lines, and primary hepatocytes with or without the simultaneous application of endothelial cells or mesenchymal stem cells (MSC). Most researchers focus on ex vivo liver engineering3,4,5,6,7,8,9,10,11,12,13,14. However, in most previous studies, only small pieces of repopulated scaffold cubes were transplanted into different heterotopic implantation sites. In a few studies, partial repopulated scaffolds were transplanted as an auxiliary graft. However, the maximal reported survival time was only 72 h8,14. As far as we know, orthotopic transplantation of a repopulated full liver graft has not yet been performed or published about. The long-term function and transplantation of engineered organs are still in their infancy. Therefore, an alternative approach to ex vivo liver engineering is needed.
In vivo liver engineering may represent an alternative to study hepatic repopulation under physiological conditions. The advantages of in vivo liver engineering compared to ex vivo liver engineering are manifold. The in vivo repopulated partial liver scaffold is subjected to physiological blood perfusion with proper temperature, sufficient oxygen, nutrients, and growth factors in contrast to ex vivo perfusion with artificial culture medium. Furthermore, the remaining partial normal liver maintains the hepatic function, principally allowing long-term survival. Since an implanted ex vivo engineered liver graft is still incapable of sustaining the long-term survival of experimental animals by its liver function8,&#160;we envision that in vivo partial liver engineeringwould ultimately become a promising model to further study the evolution of engineered livers with longer survival observations than ex vivo.
Recently, one research group (Pan and colleagues) presented, for the first time, a technique of in vivo liver engineering15. They achieved the isolated perfusion of the right inferior liver lobe in living rats despite anatomic and technical challenges. They reported the first intraoperative results of in vivo repopulation using a rat primary hepatocyte cell line. However, the in vivo surgical perfusion model of Pan et al. has disadvantages. They achieved single liver lobe perfusion in rats at the expense of completely blocking the portal vein and inferior vena cava, which may cause severe harm to the animal. The experimental rats were sacrificed after only 6 hours of intraoperative observation time. Therefore, the in vivo liver lobe perfusion technique needs further improvement to achieve postoperative survival.
We developed a novel survival model for in vivo liver lobe perfusion, based on previous studies of the hepatic anatomy of rat16, the portal vein cannulation technique for hemodynamic monitoring in mice17, and liver bioengineering18,19. The key steps for the procedure are illustrated in Figure&#160;1A - 1E.
This technique is suitable for those who want to use this experimental in vivo perfusion model for basic research on partial organ treatment by infusion with drugs, in vivo decellularization as a chemical resection for organ diseases (e.g., liver cancer), in vivo cell culture in a decellularized matrix comparing ex vivo two-dimensional and three-dimensional cell culture systems20,21,22,23,24,25,26, and in vivo liver engineering by decellularization and repopulation.

<table><tbody><tr><td>Perfusion Pump</td><td></td><td></td><td></td></tr><tr><td>Perfusor VI</td><td>B. Braun, Melsungen</td><td></td><td></td></tr><tr><td>Catheter</td><td></td><td></td><td></td></tr><tr><td>Versatus-W&amp;nbsp; Catheter</td><td>Terumo</td><td>SR+DU2419PX</td><td>24G, 0.74&amp;times;19mm</td></tr><tr><td>Versatus-W&amp;nbsp; Catheter</td><td>Terumo</td><td>SR+DU2225PX</td><td>22G, 0.9&amp;times;25mm</td></tr><tr><td>micro surgical instrument</td><td></td><td></td><td></td></tr><tr><td>micro scissors</td><td>F&amp;middot;S&amp;middot;L</td><td>No. 14058-09</td><td></td></tr><tr><td>micro serrefine</td><td>F&amp;middot;S&amp;middot;L</td><td>No.18055-05</td><td></td></tr><tr><td>Micro clamps applicator</td><td>F&amp;middot;S&amp;middot;L</td><td>No. 18057-14</td><td></td></tr><tr><td>Straight micro forceps</td><td>F&amp;middot;S&amp;middot;L</td><td>No. 00632-11</td><td></td></tr><tr><td>Curved micro forceps</td><td>F&amp;middot;S&amp;middot;L</td><td>No. 00649-11</td><td></td></tr><tr><td>micro needle-holder</td><td>F&amp;middot;S&amp;middot;L</td><td>No. 12061-01</td><td></td></tr><tr><td>general surgical instruments</td><td></td><td></td><td></td></tr><tr><td>standard sissors</td><td>F&amp;middot;S&amp;middot;L</td><td></td><td></td></tr><tr><td>mosquito clamp</td><td>F&amp;middot;S&amp;middot;L</td><td></td><td></td></tr><tr><td>serrated forcep</td><td>F&amp;middot;S&amp;middot;L</td><td></td><td></td></tr><tr><td>teethed forcep</td><td>F&amp;middot;S&amp;middot;L</td><td></td><td></td></tr><tr><td>needle-holder</td><td>F&amp;middot;S&amp;middot;L</td><td></td><td></td></tr><tr><td>suture</td><td></td><td></td><td></td></tr><tr><td>4-0 prolene</td><td>ethicon</td><td></td><td></td></tr><tr><td>4-0 ETHICON*II</td><td>ethicon</td><td></td><td></td></tr><tr><td>6-0 silk</td><td>ethicon</td><td></td><td></td></tr><tr><td>11-0 polyamide</td><td>ethicon</td><td></td><td></td></tr></tbody></table>

a novel surgical technique as a foundation for in vivo partial liver engineering in rat

Organ engineering is a novel strategy to generate liver organ substitutes that can potentially be used in transplantation. Recently, in vivo liver engineering, including in vivo organ decellularization followed by repopulation, has emerged as a promising approach over ex vivo liver engineering. However, postoperative survival was not achieved. The aim of this study is to develop a novel surgical technique of in vivo selective liver lobe perfusion in rats as a prerequisite for in vivo liver engineering. We generate a circuit bypass only through the left lateral lobe. Then, the left lateral lobe is perfused with heparinized saline. The experiment is performed with 4 groups (n = 3 rats per group) based on different perfusion times of 20 min, 2 h, 3 h, and 4 h. Survival, as well as the macroscopically visible change of color and the histologically determined absence of blood cells in the portal triad and the sinusoids, is taken as an indicator for a successful model establishment. After selective perfusion of the left lateral lobe, we observe that the left lateral lobe, indeed, turned from red to faint yellow. In a histological assessment, no blood cells are visible in the branch of the portal vein, the central vein, and the sinusoids. The left lateral lobe turns red after reopening the blocked vessels. 12/12 rats survived the procedure for more than one week. We are the first to report a surgical model for in vivo single liver lobe perfusion with a long survival period of more than one week. In contrast to the previously published report, the most important advantage of the technique presented here is that perfusion of 70% of the liver is maintained throughout the whole procedure. The establishment of this technique provides a foundation for in vivo partial liver engineering in rats, including decellularization and recellularization.

Twelve male (aged 12 - 13 weeks) Lewis rats were used to assess the effect of selective liver lobe perfusion. The experiment was performed in four groups (n = 3 rats per group). Using different perfusion periods of 20 minutes, 2 hours, 3 hours, and 4 hours, following the steps described above, we successfully achieved in vivo single lobe perfusion.
In Vivo Perfusion of the Left...

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A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

We establish a novel surgical technique for an in vivo single liver lobe perfusion model in rat as a prerequisite for further studying in vivo partial liver engineering in the future.

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

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

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Research

JoVE Journal

Bioengineering

8.0K Views.  University Hospital Jena. In de afgelopen jaren, lever engineering is uitgegroeid tot een hot topic over de hele wereld als gevolg van het potentieel van het genereren van transplantatie in staat levertransplantaties. Maar levensvatbare functie op lange termijn en de transplantatie van gemanipuleerde organen zijn nog steeds een visie op de toekomst. Onlangs in-vivo leverkwab overvloed is uitgegroeid tot een veelbelovende strategie om te beginnen met lever engineering.Een groot voordeel van deze techniek is dat ...

Video: A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

Manufacturing Devices and Instruments for Easier Rat Liver Transplantation

Orthotopic rat liver transplantation is a popular model, which has been shown in a recent JoVE paper with the use of the "quick-linker" device. This technique allows for easier venous cuff-anatomoses after a reasonable learning curve. The device is composed of two handles, which are carved out from scalpel blades, one approximator, which is obtained by modifying Kocher's forceps, and cuffs designed from fine-bore polyethylene tubing. The whole process can be performed at a low-cost using common laboratory material. The present report provides a step-by-step protocol for the design of the required pieces and includes stencils.

We describe the design of the &#x201C;quick-linker&#x201D; device for easier orthotopic rat liver transplantation.

Orthotopic rat liver transplantation is a popular model, which has been shown in a recent JoVE paper with the use of the "quick-linker" device. This ...

Orthotopic Liver Transplantation in Rats

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat liver transplantation in 1979 by Kamada et al.3, this model has remained the gold standard despite various proposed alternative techniques4. Nevertheless, its broader use is limited by its steep learning curve5.
In this video paper, we show a simple and easy-to-establish revision of Kamada's two-cuff technique. The suprahepatic vena cava anastomosis is performed manually with a running suture, and the vena porta and infrahepatic vena cava anastomoses are performed utilizing a quick-linker cuff system6. Manufacturing the quick-linker kit is shown in a separate video paper.

We present an easy-to-establish revision of the classical two-cuff technique for orthotopic liver transplantation in rat.

Clinical progress in the field of liver transplantation has been largely supported by animal models1,2. Since the publication of the first orthotopic rat ...

Medicine

Surgical Procedures for a Rat Model of Partial Orthotopic Liver Transplantation with Hepatic Arterial Reconstruction

Orthotopic liver transplantation (OLT) in rats using a whole or partial graft is an indispensable experimental model for transplantation research, such as studies on graft preservation and ischemia-reperfusion injury 1,2, immunological responses 3,4, hemodynamics 5,6, and small-for-size syndrome 7. The rat OLT is among the most difficult animal models in experimental surgery and demands advanced microsurgical skills that take a long time to learn. Consequently, the use of this model has been limited. Since the reliability and reproducibility of results are key components of the experiments in which such complex animal models are used, it is essential for surgeons who are involved in rat OLT to be trained in well-standardized and sophisticated procedures for this model.
While various techniques and modifications of OLT in rats have been reported 8 since the first model was described by Lee et al. 9 in 1973, the elimination of the hepatic arterial reconstruction 10 and the introduction of the cuff anastomosis technique by Kamada et al. 11 were a major advancement in this model, because they simplified the reconstruction procedures to a great degree. In the model by Kamada et al., the hepatic rearterialization was also eliminated. Since rats could survive without hepatic arterial flow after liver transplantation, there was considerable controversy over the value of hepatic arterialization. However, the physiological superiority of the arterialized model has been increasingly acknowledged, especially in terms of preserving the bile duct system 8,12 and the liver integrity 8,13,14.
In this article, we present detailed surgical procedures for a rat model of OLT with hepatic arterial reconstruction using a 50% partial graft after ex vivo liver resection. The reconstruction procedures for each vessel and the bile duct are performed by the following methods: a 7-0 polypropylene continuous suture for the supra- and infrahepatic vena cava; a cuff technique for the portal vein; and a stent technique for the hepatic artery and the bile duct.

Orthotopic liver transplantation in rats is an indispensable experimental model for biomedical research. Here we present our surgical procedures for orthotopic rat liver transplantation with hepatic arterial reconstruction using a 50% partial graft.

Orthotopic liver transplantation (OLT) in rats using a whole or partial graft is an indispensable experimental model for transplantation research, such as ...

Partial Lobular Hepatectomy: A Surgical Model for Morphologic Liver Regeneration

Morphological organ regeneration following acute tissue loss is common among lower vertebrates, but is rarely observed in mammalian postnatal life. Adult liver regeneration after 70% partial hepatectomy results in hepatocyte hypertrophy with some replication in remaining lobes with restoration of metabolic activity, but with permanent loss of the injured lobe&#39;s morphology and architecture. Here, we detail a new surgical method in the neonate that leaves a physiologic environment conducive to regeneration. This model involves amputation of the left lobe apex and a subsequent conservative management regimen, and lacks the necessity for ligation of major liver vessels or chemical injury, leaving a physiologic environment where regeneration may occur. We extend this protocol to amputations on juvenile (P7-14) mice, during which the injured liver transitions from organ regeneration to compensatory growth by hypertrophy. The presented, brief 30 min protocol provides a framework to study the mechanisms of regeneration, its age-associated decline in mammals, and the characterization of putative hepatic stem or progenitors.

Here, we present a new method for partial resection of the left hepatic lobe in neonatal (day 0) mice. This new protocol is suitable for studying acute liver injury and injury response in the neonatal setting.

Morphological organ regeneration following acute tissue loss is common among lower vertebrates, but is rarely observed in mammalian postnatal life. Adult ...

Developmental Biology

Rat Model of the Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy (ALPPS) Procedure

Recent clinical data support an aggressive surgical approach to both primary and metastatic liver tumors. For some indications, like colorectal liver metastases, the amount of liver tissue left behind after liver resection has become the main limiting factor of resectability of large or multiple liver tumors. A minimal amount of functional tissue is required to avoid the severe complication of post-hepatectomy liver failure, which has high morbidity and mortality. Inducing liver growth of the prospective remnant prior to resection has become more established in liver surgery, either in the form of portal vein embolization by interventional radiologists or in the form of portal vein ligation several weeks prior to resection. Recently, it was shown that liver regeneration is more extensive and rapid, when the parenchymal transection is added to portal vein ligation in a first stage and then, after only one week of waiting, resection performed in a second stage (Associating Liver Partition and Portal vein ligation for Staged hepatectomy = ALPPS). ALPPS has rapidly become popular across the world, but has been criticized for its high perioperative mortality. The mechanism of accelerated and extensive growth induced by this procedure has not been well understood. Animal models have been developed to explore both the physiological and molecular mechanisms of accelerated liver regeneration in ALPPS. This protocol presents a rat model that allows mechanistic exploration of accelerated regeneration.

Rat Model of the Associating Liver Partition and Portal Vein Ligation for Staged Hepatectomy ALPPS Procedure

Inducing rapid liver hypertrophy using Associating Liver Partition and Portal vein ligation for a Staged hepatectomy (ALPPS) has been proposed for resection of borderline resectable liver tumors. This model may elucidate mechanisms involved in rapid hypertrophy and allows testing of drugs that promote or block the acceleration of regeneration.

Recent clinical data support an aggressive surgical approach to both primary and metastatic liver tumors. For some indications, like colorectal liver ...

Intrasplenic Transplantation of Hepatocytes After Partial Hepatectomy in NOD.SCID Mice

Partial hepatectomy is a versatile and reproducible method to study liver regeneration and the effect of cell based therapeutics in various pathological conditions. Partial hepatectomy also facilitates the increased engraftment and proliferation of transplanted cells by accelerating neovascularization and cell migration towards the liver. Here, we describe a simple protocol for performing 30% hepatectomy and transplantation of cells in the spleen of a non-obese diabetic/severe combined immunodeficient NOD.SCID (NOD.CB17-Prkdcscid/J) mouse. 
In this procedure, two small incisions are made. The first incision is to expose and resect the left lobe of the liver, and another small incision is made to expose the spleen for the intrasplenic transplantation of cells. This procedure does not require any specialized surgical skills, and it can be completed in 5-7 minutes with less stress and pain, faster recovery, and better survival. We have demonstrated the transplantation of hepatocytes isolated from a green fluorescent protein (GFP) expressing mouse (Transgenic C57BL/6-Tg (UBC-GFP) 30Scha/J), as well as hepatocyte like cells of human origin (NeoHep) in partially hepatectomized NOD.SCID mice.

We have described a protocol for performing partial hepatectomy (PHx) and cell transplantation via spleen in NOD.SCID (NOD.CB17-Prkdcscid/J) mice. In this protocol, an incision is made to expose and resect the left lobe of the liver followed by another incision for the intrasplenic transplantation of cells.

Partial hepatectomy is a versatile and reproducible method to study liver regeneration and the effect of cell based therapeutics in various pathological ...

Re-Arterialized Rat Partial Liver Transplantation with an in vivo Vessel-Oriented 70% Hepatectomy

Split liver transplantation and living liver donor liver transplantation were developed in the clinic to utilize liver organs in a more efficient manner. To better understand the mechanism behind these surgical procedures, a rat partial liver transplantation (PLTx) model was established for relevant surgical studies. Because of the complexity of the rat PLTx model, a protocol with detailed descriptions is required. An article published previously reported a protocol in which ex vivo hepatectomy was used to achieve 50% rat PLTx. In contrast to this protocol, we introduced a re-arterialized PLTx with an in vivo 70% hepatectomy. An updated vessel-oriented hepatectomy was incorporated into the rat PLTx to refine the microsurgical procedure. The portal veins and hepatic arteries of the left lateral lobe and the median lobe were individually dissected and ligated before removal of the liver parenchyma, thereby decreasing the probability of bleeding in the remnant liver stump. Furthermore, an end-to-side vessel anastomosis between the common hepatic artery and the enlarged proper hepatic artery was introduced to re-arterialize the hepatic artery. By using this end-to-side vessel anastomosis technique, the diameter of the anastomosis was enlarged, thereby decreasing the difficulty of hand suture and maintaining a high rate of anastomotic patency. Moreover, the cuff anastomosis of the infrahepatic vena cava was slightly modified. A section of circumferential liver parenchyma around the vena cava of a recipient was preserved during cuff anastomosis to maintain the three-dimensional shape of the vascular lumen. This section of liver parenchyma was removed after completing the anastomosis. With this modification, the step involving placement of stay sutures was omitted, thereby further shortening the cuff anastomosis time. By using this protocol of rat PLTx, a low liver enzyme level, an intact liver lobular architecture and a high survival rate were achieved after microsurgery.

Re-Arterialized Rat Partial Liver Transplantation with an in vivo Vessel-Oriented 70% Hepatectomy

Here, a protocol involving re-arterialized rat partial liver transplantation is presented. Specifically, 70% liver was resected in vivo by using an updated technique of vessel-oriented hepatectomy. The hepatic artery was reconstructed in an end-to-side manner. The cuff technique was modified to shorten the anastomosis time of the infrahepatic vena cava.

Split liver transplantation and living liver donor liver transplantation were developed in the clinic to utilize liver organs in a more efficient manner. ...

A Rat Model of Orthotopic Liver Transplantation Using a Novel Magnetic Anastomosis Technique for Suprahepatic Vena Cava Reconstruction

The rat model of orthotopic liver transplantation (OLT) is essential for transplant research. It is a very sophisticated animal model and requires a steep learning curve. The introduction of the cuff technique for anastomosis of the portal vein (PV) and infrahepatic vena cava (IHVC) has significantly simplified the transplant procedure in rats. However, due to the short anterior wall of the recipients' suprahepatic vena cava (SHVC), the cuff technique is very difficult to use for the reconstruction of the SHVC. Most researchers in this field still use the hand-suture technique for SHVC reconstruction, which makes it the bottleneck step in rat orthotopic liver transplantation. The magnetic anastomosis technique (i.e., magnamosis) is a method of connecting two vessels using the attractive force between two magnets. Our recent study has shown that the magnetic anastomosis technique is superior to the hand-suture technique for SHVC reconstruction in rats. In this article, we show a step-by-step protocol for SHVC reconstruction in rats using the novel magnetic anastomosis technique. In this model, the reconstruction of the PV and IHVC was performed by the standard cuff technique, while the reconstruction of the bile duct (BD) was performed by a stent technique. The hepatic re-arterialization was not performed. The magnetic anastomosis technique made SHVC reconstruction much easier and significantly shortened the anphepatic phase. After a reasonable learning curve, even researchers without advanced microsurgical skills can produce reliable and reproducible results using this rat model of OLT.

The reconstruction of the suprahepatic vena cava (SHVC) remains a difficult step in rat orthotopic liver transplantation. In this article, we show a step-by-step protocol for SHVC reconstruction in rats using a novel magnetic anastomosis technique.

The rat model of orthotopic liver transplantation (OLT) is essential for transplant research. It is a very sophisticated animal model and requires a steep ...

Generation of a Rat Model of Acute Liver Failure by Combining 70% Partial Hepatectomy and Acetaminophen

Acute liver failure (ALF) is a clinical condition caused by various etiologies resulting in the loss of metabolic, biochemical, synthesizing, and detoxifying functions of the liver. In most irreversible liver damage cases, orthotropic liver transplant (OLT) remains the only available treatment. To study the therapeutic potential of a treatment for ALF, its prior testing in an animal model of ALF is essential. In the current study, an ALF model in rats was developed by combining 70% partial hepatectomy (PHx) and injections of acetaminophen (APAP) that provides a therapeutic window of 48 h. The median and left lateral lobes of the liver were removed to excise 70% of the liver mass and APAP was given 24 h postsurgically for 2 days. Survival in ALF-induced animals was found to be severely decreased. The development of ALF was confirmed by altered serum levels of the enzymes alanine amino transferase (ALT), aspartate amino transferase (AST), alkaline phosphatase (ALP); changes in prothrombin time (PT); and assessment of the international normalized ratio (INR). Study of the gene expression profile by qPCR revealed an increase in expression levels of genes involved in apoptosis, inflammation, and in the progression of liver injury. Diffused degeneration of hepatocytes and infiltration of immune cells was observed by histological evaluation. The reversibility of ALF was confirmed by the restoration of survival and serum levels of ALT, AST, and ALP after intrasplenic transplantation of syngeneic healthy rat hepatocytes. This model presents a reliable alternative to the available ALF animal models to study the pathophysiology of ALF as well as to evaluate the potential of a novel therapy for ALF. The use of two different approaches also makes it possible to study the combined effect of physical and drug-induced liver injury. The reproducibility and feasibility of current procedure is an added benefit of the model.

The acute liver failure animal model developed in the current study presents a feasible alternative for the study of potential therapies. The current model employs the combined effect of physical and drug-induced hepatic injury and provides a suitable time window to study the potential of novel therapies.

Acute liver failure (ALF) is a clinical condition caused by various etiologies resulting in the loss of metabolic, biochemical, synthesizing, and ...

Reduced Complications after Arterial Reconnection in a Rat Model of Orthotopic Liver Transplantation

The rat orthotopic liver transplantation (OLT) model is a powerful tool to study acute and chronic rejection. However, it is not a complete representation of human liver transplantation due to the absence of arterial reconnection. Described here is a modified transplantation procedure that includes the incorporation of hepatic artery (HA) reconnection, leading to a marked improvement in transplant outcomes. With a mean anhepatic time of 12 min and 14 s, HA reconnection results in improved perfusion of the transplanted liver and an increase in long-term recipient survival from 37.5% to 88.2%. This protocol includes the use of 3D-printed cuffs and holders to connect the portal vein and infrahepatic inferior vena cava. It can be implemented for studying multiple aspects of liver transplantation, from immune response and infection to technical aspects of the procedure. By incorporating a simple and practical method for arterial reconnection using a microvascular technique, this modified rat OLT protocol closely mimics aspects of human liver transplantation and will serve as a valuable and clinically relevant research model.

The goal of this study is to modify the rat orthotopic liver transplant model to better represent human liver transplantation and improve recipient survival. The presented method reestablishes hepatic arterial inflow by connecting the donor liver&#39;s common hepatic artery to the recipient liver&#39;s proper hepatic artery.

The rat orthotopic liver transplantation (OLT) model is a powerful tool to study acute and chronic rejection. However, it is not a complete representation ...

A Novel Surgical Technique As a Foundation for In Vivo Partial Liver Engineering in Rat

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