1. Donor Operation
<ol>
	<li>The donor rat should be kept fasting for 24 hr (free access to water/glucose solution).</li>
	<li>To induce Isoflurane inhalation anesthesia, start with 2% on standard atomizer, and then reduce to 1% after performing laparotomy. Perform a toe pinch to check sedation.</li>
	<li>Shave the abdomen and clean with skin prep 3 times (Kodan). Then perform a median incision after subcutaneous administration of the analgesic.</li>
	<li>After the graft is wrapped in saline soaked gauze, separate the physiological adhesions between the pancreas and the ascending colon gently with a Q-tip (under the surgical microscope with 6x magnification).</li>
	<li>Ligate and divide the ileocecal &amp; right &amp; middle colic vessels using 7-0 silk. After the ascending colon is spread out to the right side of the superior mesenteric vein (SMV), the ileocecal, right and middle colic vessels can be identified for ligation and division using 7-0 ties.</li>
	<li>Retract the stomach upward, so that the entire SMV is straightened out and exposed. Use a mosquito clamp for retraction. The clamp is held by plasticine mass formed into shape as needed.</li>
	<li>Ligate and divide the pancreatico-duodenal veins coming from the SMV. All small pancreatico-duodenal veins originating from the SMV must be carefully identified, ligated with 7-0 silk and divided before the pancreatic tissue can be removed from the graft.</li>
	<li>Ligate and divide the lose connective tissue including all lymphatics between the SMV and the abdominal aorta. With the graft still on the right side of the abdomen, the lose connective tissue including all lymphatics between the SMV and the abdominal aorta is accessible. This connective tissue must be ligated using 7-0 silk and divided to avoid postoperative lymphorrhea from the intestinal graft.</li>
	<li>Ligate and divide the right renal artery. After the connective tissue is divided, the right renal artery becomes accessible and is ligated and divided using 7-0 silk.</li>
	<li>Systemically heparinise the rat using 200 units of heparin i.v. via the penile vein.</li>
	<li>Ligate the marginal arteries, and divide the small bowel at the duodeno-jejunal junction and at the terminal ileum.</li>
	<li>The aorta is ligated proximally to the origin of the SMA. The portal vein is transected at the confluence with the splenic vein. Then the graft is harvested with its vascular pedicle consisting of the SMA with an aortic segment.</li>
</ol>
2. Backtable Procedure
<ol>
	<li>Perfuse the graft using 3 ml of University of Wisconsin solution (UW) at 4 &deg;C via the aortic conduit and irrigate the intestinal lumen from the jejunal end with 30 ml of Uro-Nebacetin N solution at 4 &deg;C (lumen irrigation is mandatory).</li>
</ol>
Immediately after extracting the graft, the aortic conduit is used for perfusion with 3 ml chilled UW solution. For this, a 20 G i.v. catheter on a 10 ml syringe is used. The perfusate should be observed to flow out freely from the divided portal vein. For the intestinal irrigation with Nebacetin, a 50 ml syringe is used.
<ol start="2">
	<li>Store the graft in UW solution at 4 &deg;C during the preparation of the recipient.</li>
</ol>
3. Recipient Operation
<ol>
	<li>The recipient rat should be kept fasting for 24 hr (free access to water/glucose solution).</li>
	<li>To induce Isoflurane inhalation anesthesia, start with 2% on standard atomizer, and then reduce to 1% after performing laparotomy. Perform a toe pinch to check sedation.</li>
	<li>Shave the abdomen and clean with skin prep 3 times (Kodan). Then perform a median incision after subcutaneous administration of Carprofen 5 mg/kg s.c. for intraoperative analgesia.</li>
	<li>Wrap the recipient bowel in normal saline soaked gauze and place it on the recipient's chest.</li>
	<li>Open the retroperitoneum bluntly with Q-tips, and expose the abdominal aorta and inferior vena cava just below the renal vessels down to the level of the iliac vessels, if necessary also use microscissors. Ligate the small lumbar and spinal tribuaries from the aorta and vena cava using 7-0 silk to avoid blood loss. (To do this, change the surgical microscope zoom to 16x.)</li>
	<li>Cross-clamp the aorta and the IVC below the left renal vessels proximally and above the iliac bifurcation distally using microvessel clips. Only one clamp is used proximally as well as distally to clamp both vessels simultaneously. Incise both vessels anteriorly using a microknife and wash out remaining blood.</li>
	<li>Create an end-to-side anastomosis between the graft aortic segment and the recipient's infrarenal aorta using a continuous 10-0 Prolene suture.. Initially, the graft is placed on the the right side of the abdomen (the head of the rat positioned at 12 o'clock) to perform the back wall stitches of the arterial anastomosis and tying of the lower stay suture. Then, the graft is turned over to the left side of the abdomen (the head of the rat positioned at 9 o'clock) to expose and suture the front wall of the anastomosis.</li>
	<li>An end-to-side anastomosis between the graft portal vein and the recipient's IVC is performed likewise by running sutures using 10-0 Prolene. With the rat still lying sideways (head in 9 o'clock position), the graft is positioned on the left side of the abdomen and a lower stay suture is placed. The anastomosis is started with the back wall from inside the vessel. After the lower stay suture is tied, the front wall stitches can be performed from outside.</li>
	<li>Remove the distal clamps first, followed by the upper clamps. Any anastomotic bleeding is controlled by direct pressure using Q-tips. The graft should be checked for equal and quick reperfusion.</li>
	<li>Resect the entire recipient's small intestine after ligation of the mesenteric vessels. Recipients undergo subtotal enterectomy, preserving 2-3 cm of proximal jejunum and 1 cm of distal ileum.</li>
	<li>Restore enteric continuity by proximal (jejuno-jejunostomy) and distal (ileo-ileostomy) end-to end intestinal anastomoses using an interrupted one-layer suture with 6-0 Monocryl. Approximately 16 sutures are needed to complete the anastomoses.</li>
	<li>Irrigate the peritoneal cavity with normal saline until clean. Administer 2 ml of normal saline intraperitoneally for fluid replacement. Then close the abdomen using a continuous suture with 3-0 Vicryl for the muscle layer plus a continuous skin suture.</li>
	<li>In the postoperative period the rats should be kept fasting (with access to water and glucose solution) for another 24 hr then restarted on standard rat chow and water ad libitum. Analgesia with carprofen should be administered for 3 days (see dosage below).</li>
</ol>

<ol>
	<li>Abu-Elmagd, 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=Five+Hundred+Intestinal+and+Multivisceral+Transplantations+at+a+Single+Center:+Major+Advances+With+New+Challenges.">Five Hundred Intestinal and Multivisceral Transplantations at a Single Center: Major Advances With New Challenges.</a> Ann. Surg. 250 (4), 567-56 (2009).</li><li>Berney, T., 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=Portal+versus+systemic+drainage+of+small+bowel+allografts:+comparative+assessment+of+survival,+function,+rejection,+and+bacterial+translocation.">Portal versus systemic drainage of small bowel allografts: comparative assessment of survival, function, rejection, and bacterial translocation.</a> J. Am. Coll. Surg. 195 (6), 804 (2002).</li><li>Fishbein, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intestinal+transplantation.">Intestinal transplantation.</a> N. Engl. J. Med. 361 (10), 998 (2009).</li><li>Hernandez, 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=Is+portal+venous+outflow+better+than+systemic+venous+outflow+in+small+bowel+transplantation?+Experimental+study+in+syngeneic+rats.">Is portal venous outflow better than systemic venous outflow in small bowel transplantation? Experimental study in syngeneic rats.</a> J. Pediatr. Surg. 40 (2), 336 (2005).</li><li>Monchik, G. J., Russell, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transplantation+of+small+bowel+in+the+rat:+technical+and+immunological+considerations.">Transplantation of small bowel in the rat: technical and immunological considerations.</a> Surgery. 70 (5), 693 (1971).</li><li>Murase, 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=Graft-versus-host+disease+after+brown+Norway-to-Lewis+and+Lewis-to-Brown+Norway+rat+intestinal+transplantation+under+FK506.">Graft-versus-host disease after brown Norway-to-Lewis and Lewis-to-Brown Norway rat intestinal transplantation under FK506.</a> Transplantation. 55 (1), 1 (1993).</li><li>Murase, 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=Immunomodulation+of+intestinal+transplant+with+allograft+irradiation+and+simultaneous+donor+bone+marrow+infusion.">Immunomodulation of intestinal transplant with allograft irradiation and simultaneous donor bone marrow infusion.</a> Transplant Proc. 31 (1-2), 565 (1999).</li><li>Pech, T., 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=Perioperative+infliximab+application+ameliorates+acute+rejection+associated+inflammation+after+intestinal+transplantation.">Perioperative infliximab application ameliorates acute rejection associated inflammation after intestinal transplantation.</a> Am. J. Transplant. 10 (11), 2431 (2010).</li><li>Schaefer, 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=Resident+macrophages+are+involved+in+intestinal+transplantation-associated+inflammation+and+motoric+dysfunction+of+the+graft+muscularis.">Resident macrophages are involved in intestinal transplantation-associated inflammation and motoric dysfunction of the graft muscularis.</a> Am J Transplant. 7 (5), 1062 (2007).</li><li>Schaefer, 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=Mechanism+and+impact+of+organ+harvesting+and+ischemia-reperfusion+injury+within+the+graft+muscularis+in+rat+small+bowel+transplantation.+Transplant.">Mechanism and impact of organ harvesting and ischemia-reperfusion injury within the graft muscularis in rat small bowel transplantation. Transplant.</a> Proc. 38 (6), 1821 (2006).</li><li>Schaefer, 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=Acute+rejection+and+the+muscularis+propria+after+intestinal+transplantation:+the+alloresponse,+inflammation,+and+smooth+muscle+function.">Acute rejection and the muscularis propria after intestinal transplantation: the alloresponse, inflammation, and smooth muscle function.</a> Transplantation. 85 (10), 1465 (2008).</li><li>Xue, L., 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=Surgical+experience+of+refined+3-cuff+technique+for+orthotopic+small-bowel+transplantation+in+rat:+a+report+of+270+cases.">Surgical experience of refined 3-cuff technique for orthotopic small-bowel transplantation in rat: a report of 270 cases.</a> Am. J. Surg. 198 (1), 110 (2009).</li><li>Zhang, X. 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=Simplified+techniques+in+rat+heterotopic+small+bowel+transplantation.">Simplified techniques in rat heterotopic small bowel transplantation.</a> Transplant. Proc. 38 (6), 1840 (2006).</li><li>Zhao, Y., 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+establishment+of+a+new+en+bloc+combined+liver-small+bowel+transplantation+model+in+rats.+Transplant.">The establishment of a new en bloc combined liver-small bowel transplantation model in rats. Transplant.</a> Proc. 39 (1), 278 (2007).</li></ol>

No conflicts of interest declared.

While intestinal transplant models in rats have been described as early as in the 1970ies 5 most of the recently employed models involve heterotopic intestinal transplantation using different techniques 13. While the heterotopic procedures in general have the advantage of easier microsurgical techniques and easier accessibility of the graft for assessment, heterotopic intestinal transplantation has the big disadvantage of not taking into account the multiple interactions of the transplanted small bowel and its functional aspects like contractile activity and mucosal barrier function that characterizes an orthotopic graft in the context of a vast host of commensals and pathogens. Our group has gained a large experience with the herein described orthotopic model and our findings suggest that many of the specific alterations caused by inflammatory and adaptive immune responses have to be assessed in context with the functional properties of the transplanted small bowel like contractility and mucosal integrity. Of note, the anastomotic techniques employed here do not include the usage of arterial or venous cuffs, some of which have been shown to facilitate the procedure and reduce the critical warm ischemia time, especially in models of multivisceral transplantation 12,14. Although it may be necessary to employ cuff techniques in rodent models of multivisceral transplantation, the complicative potential of the cuffs has led us to avoid similar techniques in this model of single intestinal transplantation. We have not attempted to use portal drainage techniques in this model. Apart from being technically challenging (the small portal vein diameter could lead to venous outflow problems), which would make the whole model more difficult to establish - it is a fact that in clinical intestinal transplantation systemic drainage is used in the majority of cases. Thus, the described technique reflects clinical practice combined with technical feasibility. Portal drainage of the grafts has not been shown to be associated with superior outcomes in several clinical and experimental studies 2,4. Sufficiently short ischemia times of around 35 minutes necessary for stable animal survival can be achieved after completion of the learning curve for this model.
Orthotopic small bowel transplantation according to this protocol can be learned by a microsurgically experienced researcher after performing approximately 30-40 procedures. The visualization as achieved by the JoVE format allows for direct visual observation and accurate reproduction of the employed techniques that possibly leads to quicker establishment of the method and less animal sacrifice. Critical points are bleeding, cold and warm ischemia time and bowel anastomotic stenosis/insufficiency. The cold ischemia time in this experimental setting is not as crucial as warm ischemia time but should not exceed 45 minutes. The warm ischemia time should be around 35 minutes and also not exceed 45 minutes, as this may cause higher postoperative mortality. The ideal donor and recipient weight is around 200 g because smaller rats do not tolerate the procedure well and weight over 300 g is associated with excessive intraabdominal fat. The rats lose up to 20% of body weight in the direct postoperative period but should start to gain weight again after 6-8 days postoperatively (Figure 2). Daily health checks (alertness, fur and mucosal appearance, weight, stool quality and frequency) should be performed until the animal is sacrificed. We recommend daily administration of antibiotics and analgesia for at least the first three days as described above. After initial practice, particularly of the microvascular and bowel anastomoses, this model provides reliable and stable long term survival of around 80-90% in the isogenic setting. In the allogenic setting survival is generally lower, depends mainly on immunologic phenomena like acute and chronic rejection and may vary widely according to the immunosuppressive regimen used and tested.
Technical notes: The donor operation time should be about 45 minutes. The recipient operation should not much exceed 1.5 hours. A heating pad should be used routinely to avoid hypothermia in the recipient. For easy vascular access, the lateral tail vein of the recipient can be cannulated at the beginning of the procedure using a 22 G intravenous catheter. Irrigation of the intestinal lumen, as described above may not be necessary, omitting this step has to our knowledge no negative effects on outcome and mortality.
Animal study requirements: The animals were kept according to applying laws and regulations of the Federal Republic of Germany, State North Rhine-Westfalia. The document numbers under which the experiments were approved can be requested from the corresponding author.

<table border="1">
 <tbody>
 <tr>
 <td>Name of the reagent</td>
 <td>Company</td>
 <td>Catalogue number</td>
 <td>Comments (optional)</td>
 </tr>
 <tr>
 <td>University of Wisconsin (UW) solution (ViaSpan)</td>
 <td>Bristol-Myers Squibb </td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Uro-Nebacetin N solution</td>
 <td>Nycomed</td>
 <td>6967855</td>
 <td></td>
 </tr>
 <tr>
 <td>Ampicillin</td>
 <td>Ratiopharm</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Carprofen (Rimadyl)</td>
 <td>Pfizer</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Prolene 10-0 unresorbable suture</td>
 <td>Ethicon</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Monocryl 6-0 resorbable suture</td>
 <td>Ethicon</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Vicryl 3-0 resorbable suture</td>
 <td>Ethicon</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>i.v. Catheter G 20 1.1x33 mm</td>
 <td>Braun</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>i.v. Catheter G 22 0.9x25 mm</td>
 <td>Braun</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Kodan Skin Prep</td>
 <td>Sch&uuml;lke</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>NaCl 0.9% Infusion solution</td>
 <td>Braun</td>
 <td></td>
 <td></td>
 </tr>
 <tr>
 <td>Curved forceps small </td>
 <td>FineScienceTools</td>
 <td>11009-13 </td>
 <td></td>
 </tr>
 <tr>
 <td>Micro forceps curved </td>
 <td>AESCULAP </td>
 <td>BD 333 </td>
 <td></td>
 </tr>
 <tr>
 <td>Micro forceps curved </td>
 <td>AESCULAP </td>
 <td>FD281R </td>
 <td></td>
 </tr>
 <tr>
 <td>Micro forceps straight 1 </td>
 <td>WPI</td>
 <td>5</td>
 <td></td>
 </tr>
 <tr>
 <td>Micro forceps straight 2 </td>
 <td>WPI</td>
 <td>2</td>
 <td></td>
 </tr>
 <tr>
 <td>Micro needle holder </td>
 <td>WPI </td>
 <td>14081 </td>
 <td></td>
 </tr>
 <tr>
 <td>Micro scissors</td>
 <td>FineScienceTools</td>
 <td>15006-09 </td>
 <td></td>
 </tr>
 <tr>
 <td>Micro scalpel </td>
 <td>MANI</td>
 <td>Ophthalmic knife</td>
 <td></td>
 </tr>
 <tr>
 <td>Micro clamps</td>
 <td>AESCULAP </td>
 <td>FB329R </td>
 <td></td>
 </tr>
 </tbody>
</table>

orthotopic small bowel transplantation in rats

Small bowel transplantation has become an accepted clinical option for patients with short gut syndrome and failure of parenteral nutrition (irreversible intestinal failure). In specialized centers improved operative and managing strategies have led to excellent short- and intermediate term patient and graft survival while providing high quality of life 1,3. Unlike in the more common transplantation of other solid organs (i.e. heart, liver) many underlying mechanisms of graft function and immunologic alterations induced by intestinal transplantation are not entirely known6,7. Episodes of acute rejection, sepsis and chronic graft failure are the main obstacles still contributing to less favorable long term outcome and hindering a more widespread employment of the procedure despite a growing number of patients on home parenteral nutrition who would potentially benefit from such a transplant. The small intestine contains a large number of passenger leucocytes commonly referred to as part of the gut associated lymphoid system (GALT) this being part of the reason for the high immunogenity of the intestinal graft. The presence and close proximity of many commensals and pathogens in the gut explains the severity of sepsis episodes once graft mucosal integrity is compromised (for example by rejection). To advance the field of intestinal- and multiorgan transplantation more data generated from reliable and feasible animal models is needed. The model provided herein combines both reliability and feasibility once established in a standardized manner and can provide valuable insight in the underlying complex molecular, cellular and functional mechanisms that are triggered by intestinal transplantation. We have successfully used and refined the described procedure over more than 5 years in our laboratory 8-11. The JoVE video-based format is especially useful to demonstrate the complex procedure and avoid initial pitfalls for groups planning to establish an orthotopic rodent model investigating intestinal transplantation.

Normal postoperative course
The transplanted animals should recover quickly from the procedure under a heat lamp for approximately 1 hr. Hypothermia is a major cause of postoperative mortality and should be carefully avoided intra- and postoperatively. Intraoperative fluid losses must be replaced by s.c. injection of 2.5 ml normal saline plus 2.5 ml Glucose 5% every 8 hr for the first 24 hr. The rats should also have free access to glucose solution (or gel diet) and water p.o. for the first 24 hr postoperatively. After this period they should regain normal feeding behavior with free access to standard rat chow and water ad libitum. Pain is controlled by administration of carprofen 5 mg/kg s.c. daily for three days, with the first shot to be administered at anesthesia induction. Perioperative antibiotic prophylaxis is only needed in the allogenic setting, and can be administered over 5-7 days (ampicillin 15 mg/kg s.c., q. 12 hr). General appearance, fur condition as well as mucosal appearance should be normal. After POD 1 the activity level should return to preoperative status, apathic or abnormal behavior suggests early surgical complications. After initial loss of up to 20% of body weight the rats will start to gain weight again around postoperative day 6-8 and will have reached around 90 % of their preoperative weight normally around postoperative day 14 (in the isogenic setting without rejection).
Postoperative complications
As stated above, a distended abdomen, apathic behavior, discontinuation of feeding and changes in general appearance (ruffled fur, secretion from the eyes) should be considered as symptoms of possible complications. The animals should be seen by the surgeon and a veterinarian. Conditions like dehydration, inflammatory state due to peritonitis, ileus due to stenosis of the bowel anastomosis, insufficient pain medication and others must be ruled out and treated. If the animal does not recover despite treatment, discontinuation of the experiment must be evaluated on a case by case basis according to applying animal experiment regulations.
<img alt="Figure 1a" src="/files/ftp_upload/4102/4102fig1a.jpg" /> 
 Figure 1a. Instruments. 
1. Microscope (LEICA) 
2. Anesthesia apparatus (EICKEMEYER)
<img alt="Figure 1b" src="/files/ftp_upload/4102/4102fig1b.jpg" /> 
 Figure 1b. Instruments. 
3. Shaver 
4. Electronic scalpel (GEIGER) 
5. Surgical forceps 
6. DeBakey forceps curved 
7. Curved forceps small 
8. Micro forceps curved 
9. Micro forceps straight 1 
10. Micro forceps straight 2 
11. Micro needle holder 
12. Needle holder 
13. Mosquito clamp 
14. Scissors 1 
15. Scissors 2 
16. Microscissors 
17. Micro Scalpel
<img alt="Figure 1c" src="/files/ftp_upload/4102/4102fig1c.jpg" /> 
 Figure 1c. Instruments. 
18. Microclamps 
19. Canulas and Q-Tips (not depicted) 
20. Syringes (50 ml, 10 ml, 2.5 ml, 1 ml)
<img alt="Figure 1d" src="/files/ftp_upload/4102/4102fig1d.jpg" /> 
 Figure 1c. Instruments. 
21. UW solution for graft storage 
22. Antibiotics (Uro-nebacetin N) for graft lumen irrigation 
23. UW for graft perfusion 
24. Normal saline 
25. Dish with normal saline (for backtable)
<img alt="Figure 2" src="/files/ftp_upload/4102/4102fig2.jpg" /> 
 Figure 2. Average postoperative weight (cumulative data). Figure 2 shows the average postoperative weight after orthotopic small bowel transplantation. After initial loss of up to 20% of body weight the rats start to gain weight again around postoperative day 6-8 and will have reached 90% of their preoperative weight normally around postoperative day 14 (in the isogenic setting without rejection / immunosuppression). Figure 2 represents weight loss data, not survival, the decreasing number of available animals to measure weight loss is mainly due to sacrifing of animals for experiments.
<img alt="Figure 3" src="/files/ftp_upload/4102/4102fig3.jpg" /> 
 Figure 3. The pancreatic tissue (arrow) has to be removed from the colon.
<img alt="Figure 4" src="/files/ftp_upload/4102/4102fig4.jpg" /> 
 Figure 4. After ligating and dividing the lose connective tissue including all lymphatics between SMV and the abdominal aorta, the right renal artery (arrow) is divided between silk ligatures.
<img alt="Figure 5" src="/files/ftp_upload/4102/4102fig5.jpg" /> 
 Figure 5. Perfusion of the graft with UW solution via the aortic conduit.
<img alt="Figure 6" src="/files/ftp_upload/4102/4102fig6.jpg" /> 
 Figure 6. After preparation of recipient vena cava and aorta the vessels are exposed, ready for clamping.
<img alt="Figure 7" src="/files/ftp_upload/4102/4102fig7.jpg" /> 
 Figure 7. Cross clamp is performed on vena cava and aorta simultaneously using microclamps.
<img alt="Figure 8" src="/files/ftp_upload/4102/4102fig8.jpg" /> 
 Figure 8. (a) The aorto-aortic anastomosis is performed using stay sutures. (b)After completion of the aorto-aortic anastomosis, the portocaval anastomosis will be performed next. The lower stay suture is already in place.
<img alt="Figure 9" src="/files/ftp_upload/4102/4102fig9.jpg" /> 
 Figure 9. (a) The portocaval anastomosis is started after the second stay suture is in place. (b) After completion of the portocaval anastomosis.
<img alt="Figure 10" src="/files/ftp_upload/4102/4102fig10.jpg" /> 
 Figure 10. After removal of the clamps the graft reperfuses well.
<img alt="Figure 11" src="/files/ftp_upload/4102/4102fig11.jpg" /> 
 Figure 11. (a) Placement of stay sutures for the bowel anastomosis. (b) Completed bowel anastomosis.

Watch this Scientific Journal Video about Orthotopic Small Bowel Transplantation in Rats at JoVE.com

Orthotopic Small Bowel Transplantation in Rats

Small bowel transplantation has become an accepted treatment option for patients with irreversible intestinal failure. Our experimental model of orthotopic small bowel transplantation in rats serves as a reliable tool to address underlying immunologic and inflammatory processes that complicate intestinal transplantation.

Small  bowel transplantation has become an accepted clinical option for patients with  short gut syndrome and failure of parenteral nutrition ...

orthotopic-small-bowel-transplantation-in-rats

Nanyang Technological University

Research

JoVE Journal

Medicine

14.1K Views.  University of Bonn, Germany. Small bowel transplantation has become an accepted treatment option for patients with irreversible intestinal failure. Our experimental model of orthotopic small bowel transplantation in rats serves as a reliable tool to address underlying immunologic and inflammatory processes that complicate intestinal transplantation.

Video: Orthotopic Small Bowel Transplantation in Rats

Development of Obliterative Bronchiolitis in a Murine Model of Orthotopic Lung Transplantation

Orthotopic lung transplantation in rats was first reported by Asimacopoulos and colleagues in 1971 1. Currently, this method is well accepted and standardized not only for the study of allo-rejection but also between syngeneic strains for examining mechanisms of ischemia-reperfusion injury after lung transplantation. Although the application of the rat and other large animal model 2 contributed significantly to the elucidation of these studies, the scope of those investigations is limited by the scarcity of knockout and transgenic rats. Due to no effective therapies for obliterative bronchiolitis, the leading cause of death in lung transplant patients, there has been an intensive search for pre-clinical models that replicate obliterative bronchiolitis. The tracheal allograft model is the most widely used and may reproduce some of the histopathologic features of obliterative bronchiolitis 3. However, the lack of an intact vasculature with no connection to the recipient's conducting airways, and incomplete pathologic features of obliterative bronchiolitis limit the utility of this model 4. Unlike transplantation of other solid organs, vascularized mouse lung transplants have only recently been reported by Okazaki and colleagues for the first time in 2007 5. Applying the basic principles of the rat lung transplant, our lab initiated the obliterative bronchiolitis model using minor histoincompatible antigen murine orthotopic single-left lung transplants which allows the further study of obliterative bronchiolitis immunopathogenesis6.

Obliterative bronchiolitis is the key impediment to the long-term survival of lung transplant recipients and the lack of a robust preclinical model precludes examining obliterative bronchiolitis immunopathogenesis. Unlike other solid organ transplants, vascularized mouse lung transplantation has only recently been developed. Here we show our independently developed obliterative bronchiolitis model after murine orthotopic single-lung transplantation.

Orthotopic lung transplantation in rats was first reported by Asimacopoulos and colleagues in 1971 1. Currently, this method is well accepted and ...

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 ...

Orthotopic Aortic Transplantation in Mice for the Study of Vascular Disease

Vascular procedures involving anastomoses in the mouse are generally thought to be difficult and highly dependent on the skill of the individual surgeon. This is largely true, but there are a number of important principles that can reduce the difficulty of these procedures and enhance reproducibility. Orthotopic aortic transplantation is an excellent procedure in which to learn these principles because it involves only two end-to-end anastomoses, but requires good suturing technique and handling of the vessels for consistent success. This procedure begins with the procurement of a length of abdominal aorta from a donor animal, followed by division of the native aorta in the recipient. The procured aorta is then placed between the divided ends of the recipient aorta and sutured into place using end-to-end anastomoses. To accomplish this objective successfully requires a high degree of concentration, good tools, a steady hand, and an appreciation of how easily the vasculature of a mouse can be damaged, resulting in thrombosis. Learning these important principles is what occupies most of the beginner's time when learning microsurgery in small rodents. Throughout this protocol, we refer to these important points. This model can be used to study vascular disease in a variety of different experimental systems1-8. In the context shown here, it is most often used for the study of post-transplant vascular disease, a common long-term complication of solid organ transplantation in which intimal hyperplasia occurs within the allograft. The primary advantage of the model is that it facilitates quantitative morphometric analyses and the transplanted vessel lies contiguous to the endogenous vessel, which can serve as an additional control9. The technique shown here is most often used for mice weighing 18-25 grams. We have accumulated most of our experience using the C57BL/6J, BALB/cJ, and C3H/HeJ strains.

We describe a technique in which a section of the abdominal aorta from a mouse is transplanted orthotopically to just below the renal arteries in an allogeneic or syngeneic recipient. This technique can be useful in studies in which transplantation of large arteries of uniform size is deemed advantageous.

Vascular procedures involving anastomoses in the mouse are generally thought to be difficult and highly dependent on the skill of the individual surgeon. ...

Orthotopic Hind Limb Transplantation in the Mouse

In vivo animal model systems, and in particular mouse models, have evolved into powerful and versatile scientific tools indispensable to basic and translational research in the field of transplantation medicine. A vast array of reagents is available exclusively in this setting, including mono- and polyclonal antibodies for both diagnostic and interventional applications. In addition, a vast number of genotyped, inbred, transgenic, and knock out strains allow detailed investigation of the individual contributions of humoral and cellular components to the complex interplay of an immune response and make the mouse the gold standard for immunological research. 
Vascularized Composite Allotransplantation (VCA) delineates a novel field of transplantation using allografts to replace "like with like" in patients suffering traumatic or congenital tissue loss. This surgical methodological protocol shows the use of a non-suture cuff technique for super-microvascular anastomosis in an orthotopic mouse hind limb transplantation model. The model specifically allows for comparison between established paradigms in solid organ transplantation with a novel form of transplants consisting of various different tissue components. Uniquely, this model allows for the transplantation of a viable vascularized bone marrow compartment and niche that have the potential to exert a beneficial effect on the balance of immune acceptance and rejection. This technique provides a tool to investigate alloantigen recognition and allograft rejection and acceptance, as well as enables the pursuit of functional nerve regeneration studies to further advance this novel field of transplantation.

This novel model for orthotopic hind limb transplantation in the mouse, applying a non-suture cuff technique for super-microvascular anastomosis, provides a powerful tool for in&#160;vivo mechanistic immunological research related to vascularized composite allotransplantation (VCA).

In vivo animal model systems, and in particular mouse models, have evolved into powerful and versatile scientific tools indispensable to basic and ...

Transarterial Administration of Oncolytic Viruses for Locoregional Therapy of Orthotopic HCC in Rats

Hepatocellular carcinoma (HCC) is a disease with limited treatment options and poor prognosis. In recent years, oncolytic virotherapies have proven themselves to be potentially powerful tools to fight malignancy. Due to the unique dual blood supply in the liver, it is possible to apply therapies locally to orthotopic liver tumors, which are predominantly fed by arterial blood flow. We have previously demonstrated that hepatic arterial delivery of oncolytic viruses results in safe and efficient transduction efficiency of multifocal HCC lesions, resulting in significant prolongation of survival in immune competent rats. This procedure closely mimics the application of transarterial embolization in patients, which is the standard palliative care provided to many HCC patients. The ability to administer tumor therapies through the hepatic artery in rats allows for a highly sophisticated preclinical model for evaluating novel viral vectors under development. Here we describe the detailed protocol for microdissection of the hepatic artery for infusion of oncolytic virus vectors to treat orthotopic HCC.

Oncolytic virotherapies are under development as novel therapeutics for the treatment of hepatocellular carcinoma (HCC). Here we describe a method for locoregional therapy of HCC via hepatic arterial administration of oncolytic virus.

Hepatocellular carcinoma (HCC) is a disease with limited treatment options and poor prognosis.  In recent years, oncolytic virotherapies have proven ...

A Pre-Clinical Porcine Model of Orthotopic Heart Transplantation

Fifty-years following the first successful report, cardiac transplantation remains the gold-standard treatment for eligible patients with advanced heart failure. Multiple small-animal models of heart transplantation have been used to study the acute and long-term effects of novel therapies. However, few are tested and demonstrated success in clinical trials. It is of critical importance to evaluate new therapies in a clinically relevant large-animal model for efficient and reliable translation of basic studies&#39;&#160;findings. Here, we describe a pre-clinical large-animal (porcine) model of orthotopic heart transplantation that has been firmly established and previously used to investigate novel cardioprotective strategies. This procedure focuses on acute ischemia-reperfusion injury and is a reliable method to investigate novel interventions which have been tested and validated in smaller experimental models, such as the murine model. We demonstrate its usefulness in assessing cardiac performance during the early post-transplantation period and other potential possibilities enabled by the model.

Here, we describe a pre-clinical large-animal (porcine) model of orthotopic heart transplantation that has been firmly established and utilized to investigate novel cardioprotective strategies.

Fifty-years following the first successful report, cardiac transplantation remains the gold-standard treatment for eligible patients with advanced heart ...

Orthotopic Rat Kidney Transplantation: A Novel and Simplified Surgical Approach

Kidney transplantation offers increased survival rates and improved quality of life for patients with end-stage renal disease, as compared to any type of renal replacement therapy. Over the past few decades, the rat kidney transplantation model has been used to study the immunological phenomena of rejection and tolerance. This model has become an indispensable tool to test new immunomodulatory pharmaceuticals and regimens prior to proceeding with expensive preclinical large animal studies.
This protocol provides a detailed overview of how to reliably perform orthotopic kidney transplantation in rats. This protocol includes three distinctive steps that increase the probability of success: perfusion of the donor kidney by flushing through the portal vein and the use of a cuff system to anastomose the renal veins and ureters, thereby decreasing cold and warm ischemia times. Using this technique, we have achieved survival rates beyond 6 months with normal serum creatinine in animals with syngeneic or tolerant kidney transplants. Depending on the aim of the study, this model can be modified by pre- or posttransplant treatments to study the acute, chronic, cellular, or antibody-mediated rejection. It is a reproducible, reliable, and cost-effective animal model to study different aspects of kidney transplantation.

The purpose of this manuscript and protocol is to explain and demonstrate in detail the surgical procedure of orthotopic kidney transplantation in rats. This method is simplified to achieve the correct perfusion of the donor kidney and shorten the reperfusion time by using the venous and ureteral cuff anastomosis technique.

Kidney transplantation offers increased survival rates and improved quality of life for patients with end-stage renal disease, as compared to any type of ...

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 ...

Orthotopic Kidney Auto-Transplantation in a Porcine Model Using 24 Hours Organ Preservation And Continuous Telemetry

In the present era of organ transplantation with critical organ shortage, various strategies are employed to expand the pool of available allografts for kidney transplantation (KT). Even though, the use of allografts from extended criteria donors (ECD) could partially ease the shortage of organ donors, ECD organs carry a potentially higher risk for inferior outcomes and postoperative complications. Dynamic organ preservation techniques, modulation of ischemia-reperfusion and preservation injury, and allograft therapies are in the spotlight of scientific interest in an effort to improve allograft utilization and patient outcomes in KT.
Preclinical animal experiments are playing an essential role in translational research, especially in the medical device and drug development. The major advantage of the porcine orthotopic auto-transplantation model over ex vivo or small animal studies lies within the surgical-anatomical and physiological similarities to the clinical setting. This allows the investigation of new therapeutic methods and techniques and ensures a facilitated clinical translation of the findings. This protocol provides a comprehensive and problem-oriented description of the porcine orthotopic kidney auto-transplantation model, using a preservation time of 24 hours and telemetry monitoring. The combination of sophisticated surgical techniques with highly standardized and state-of-the-art methods of anesthesia, animal housing, perioperative follow up, and monitoring ensure the reproducibility and success of this model.

Large animal models play an essential role in preclinical transplantation research. Due to its similarities to the clinical setup, the porcine model of orthotopic kidney auto-transplantation described in this article provides an excellent in vivo setting for the testing of organ preservation techniques and therapeutic interventions.

In the present era of organ transplantation with critical organ shortage, various strategies are employed to expand the pool of available allografts for ...

Left Lung Orthotopic Transplantation in a Juvenile Porcine Model for ESLP

Lung transplantation is the gold-standard treatment for end-stage lung disease, with over 4,600 lung transplantations performed worldwide annually. However, lung transplantation is limited by a shortage of available donor organs. As such, there is high waitlist mortality. Ex situ lung perfusion (ESLP) has increased donor lung utilization rates in some centers by 15%-20%. ESLP has been applied as a method to assess and recondition marginal donor lungs and has demonstrated acceptable short- and long-term outcomes following transplantation of extended criteria donor (ECD) lungs. Large animal (in vivo) transplantation models are required to validate ongoing in vitro research findings. Anatomic and physiologic differences between humans and pigs pose significant technical and anesthetic challenges. An easily reproducible transplant model would permit the&#160;in vivo&#160;validation of current ESLP strategies and the preclinical evaluation of various interventions designed to improve donor lung function. This protocol describes a porcine model of orthotopic left lung allotransplantation. This includes anesthetic and surgical techniques, a customized surgical checklist, troubleshooting, modifications, and the benefits and limitations of the approach.

This protocol describes a juvenile porcine model of orthotopic left lung allotransplantation designed for use with ESLP research. Focus is made on anesthetic and surgical techniques, as well as critical steps and troubleshooting.

Lung transplantation is the gold-standard treatment for end-stage lung disease, with over 4,600 lung transplantations performed worldwide annually. ...