The authors would like to thank Jean Pierre Marmuse for his constant help and support; Eglantine Voitellier, Jean-Baptiste Cavin, and Houneyda El Jindi for setting up the models and the illustrations; Anne-Charlotte Jarry and Andreia Goncalves for their help with the videos; Sara J. Zaat for editing the text in English. Matthieu A. Siebert and Lara Ribeiro-Parenti were recipients of sponsorships from the Fondation pour la recherch&#233; m&#233;dicale (FRM) and the Association fran&#231;aise de chirurgie (AFC).

All animal use conformed to the European Community guidelines and was approved by the local ethics committee (Comit&#233; d&#39;&#233;thique en exp&#233;rimentation animale N&#176; 121) and the Ministry of Higher Education and Research (Ref #02285.03).
1. Animals and Diets
<ol>
	<li>Rats
	<ol>
		<li>Use male Wistar rats weighing 260 - 320 g, started on a high-fat diet (HFD) at 7 weeks of age.</li>
	</ol>
	</li>
	<li>Diet
	<ol>
		<li>Induce a diet-induced obesity, with at least 12 preoperative weeks of the HFD. Give the rats free access to water and the HFD. 
		NOTE: The HFD consists of a purified laboratory hypercaloric rodent diet containing 45% fat (see Table of Materials).</li>
		<li>Ensure that the rats are obese at the time of surgery, with a weight between 600 - 800 g.</li>
	</ol>
	</li>
</ol>
2. Material
<ol>
	<li>Surgical equipment
	<ol>
		<li>Autoclave all surgical instruments before surgery.</li>
		<li>Lay out all the surgical instruments needed for the procedure (see Table of Materials).</li>
		<li>Perform the anastomosis under magnifying glasses, using conventional and microsurgical instruments.</li>
		<li>Ensure that the rats are positioned on the warming plate at a temperature of 37 &#176;C and under a heat lamp. Position the isothermal electric board as needed.</li>
	</ol>
	</li>
	<li>Anesthesia and animal preparation
	<ol>
		<li>Anesthetize the rat with an inhalation of 3% vol isoflurane in air for the induction of the anesthesia in the rodent box.</li>
		<li>Transfer the rat to the warming plate and maintain the anesthesia with the facemask at the same flow rate of 3%. Ensure that the anesthetization is complete by pinching the tail of the animal.</li>
		<li>Shave the anterior fur, corresponding to the laparotomy&#39;s incision zone, a ~3 cm-wide zone from the xiphoid to the animal pelvis, using an electric razor.</li>
		<li>Shave a 3 cm-wide zone on the back of the animal, centered on the neck of the animal. This step facilitates monopolar power conduction.</li>
		<li>Spray an alcohol-based disinfectant solution over the operation site.</li>
	</ol>
	</li>
</ol>
3. Surgery
<ol>
	<li>Laparotomy
	<ol>
		<li>Apply alcohol-based local antiseptic on the shaved skin.</li>
		<li>Open the abdomen with a midline cutaneous incision from the xiphoid process of about 3 cm in length with a scalpel. Open the fascia and the peritoneum along the linea alba with a monopolar scalpel.</li>
		<li>Ensure that the peritoneal cavity is opened on the entire length of the cutaneous incision. 
		Expose the peritoneal cavity with a self-retractor.</li>
	</ol>
	</li>
	<li>Greater curve and hiatal dissection
	<ol>
		<li>Dissect the greater gastric curve from the junction between the glandular and nonglandular stomach to the left side of the abdominal esophagus with surgical scissors.</li>
		<li>Progressively coagulate the gastrosplenic vessels with the monopolar scalpel, in order to fully liberate the great gastric curve to the His angle. Then expose the hiatal area by sectioning of thin ligaments.</li>
		<li>Dissect the right side of the abdominal esophagus, preserving the left gastric artery and vagal nerve, using a manual dissector.</li>
	</ol>
	</li>
	<li>Gastric pouch confection
	<ol>
		<li>Nonglandular stomach ablation
		<ol>
			<li>Apply a 35 mm staple gun (see Table of Materials) at the junction between the glandular and nonglandular stomach to the left side of the gastroesophageal junction. Ensure that the nonglandular stomach is on the right side of the stapler.</li>
			<li>Fire the gun and then remove the resected nonglandular stomach.</li>
		</ol>
		</li>
		<li>Gastric pouch
		<ol>
			<li>Apply a second stapler using a thoraco-abdominal (TA) device (3 - 3.5 mm) (see Table of Materials), parallel to the first stapling, on the right side of the gastroesophageal junction to exclude the antrum and a part of the body of the stomach.</li>
			<li>Ensure that the result of the two staple lines is a gastric pouch about 0.5 cm wide.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>OAGB
	<ol>
		<li>Small bowel measurement
		<ol>
			<li>Locate the duodenojejunal angle. The proximal jejunum is the small bowel portion located under the medial portion of the colon; it is the only nonmobile part of the small bowel in the rat.</li>
			<li>With a 5 cm-long tape, manually measure 35 cm from the duodenojejunal angle. Then perform a punctiform enterotomy on the antimesenteric side of the jejunum.</li>
		</ol>
		</li>
		<li>Gastrojejunal anastomosis
		<ol>
			<li>Perform a punctiform gastrotomy with the monopolar scalpel on the greater curve side of the gastric pouch, precisely between the two previous staple lines. If the gastric pouch is not totally empty, perform gentle manual pressure on the gastric pouch to empty it.</li>
			<li>Perform an end-to-side gastrojejunal anastomosis with nontraumatic forceps and a small needle-holder.</li>
			<li>Start the suture with two extremity stitches of 7-0 isotactic polypropylene (see Table of Materials), suturing the two extremities of the gastrotomy with the extremities of the enterotomy.</li>
			<li>Then, with the same threads used for the two extremity stitches, perform two running sutures on each side of the anastomosis. If needed, return the anastomosis to facilitate the maneuver. Ensure the quality of the anastomosis by placing close stitches, at least seven or eight on each side of the anastomosis.</li>
			<li>Take 1 mm-wide serosa in every stitch. Avoid taking any mucosa in the stitch in order to gently bury the enteric and gastric mucosa inside the suture. 
			NOTE: The result of this is a terminolateral gastrojejunal anastomosis with a biliopancreatic limb on the left and an alimentary (AL)/CL on the right. Ensure that the anastomosis is permeable with gentle pressure on the gastric pouch.</li>
		</ol>
		</li>
	</ol>
	</li>
	<li>Closure and immediate care
	<ol>
		<li>Rinse the peritoneal cavity with 0.9% NaCl solution and manually replace the abdominal organs into their physiological positions.</li>
		<li>Close the abdominal wall with one running suture of braided polyester suture 2-0 (see Table of Materials) with a classical needle-holder.</li>
		<li>Close the skin with one running suture of polyglactin 910 4-0 (see Table of Materials).</li>
		<li>Perform two parietal injections of lidocaine 1% on each side of the laparotomy. Administer a total dose of 1 mL/kg of lidocaine 1% into the rectus abdominal muscle aponeurosis.</li>
	</ol>
	</li>
</ol>
4. Postoperative Care
<ol>
	<li>Perform an intramuscular injection of 20,000 units/kg penicillin G.</li>
	<li>Perform a subcutaneous injection of 10 mL of isotonic polyionic solution potassium (2 g of KCl/L, 4 g of NaCl/L, and 50 g of glucose/L). In this injection, it is possible to mix with suitable analgesics such as buprenorphine (0.1mg/kg) and meloxicam (2mg/kg).</li>
	<li>Place the rats in individual cages warmed up by a lamp until they are fully awake.</li>
	<li>Frequently inspect the animals in order to administer postoperative treatment with suitable analgesia and hydration (isotonic polyionic solution).</li>
	<li>Inject suitable analgesic, buprenorphine (0.1 mg/kg) and meloxicam (2 mg/kg), subcutaneously from the immediate postoperative period till day 4, every 12 h.</li>
	<li>Keep the rats with free access to water during day 1. On day 2/3, give them free access to a liquid diet. On day 4, give them ad libitum access to a normal diet.</li>
</ol>

<ol>
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Consensus conference statement bariatric surgery for morbid obesity: health implications for patients, health professionals, and third-party payers.</a> Surgery for Obesity and Related Disease. 1, 371-381 (2005).</li><li>Mingrone, G., 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=Bariatric-metabolic+surgery+versus+conventional+medical+treatment+in+obese+patients+with+type+2+diabetes:+5+year+follow-up+of+an+open-label,+single-centre,+randomised+controlled+trial.">Bariatric-metabolic surgery versus conventional medical treatment in obese patients with type 2 diabetes: 5 year follow-up of an open-label, single-centre, randomised controlled trial.</a> Lancet. 386, 964-973 (2015).</li><li>Nguyen, N. T., Varela, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bariatric+surgery+for+obesity+and+metabolic+disorders:+state+of+the+art.">Bariatric surgery for obesity and metabolic disorders: state of the art.</a> Nature Reviews. Gastroenterology &amp; Hepatology. 14, 160-169 (2017).</li><li>Rutledge, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+mini-gastric+bypass:+experience+with+the+first+1,274+cases.">The mini-gastric bypass: experience with the first 1,274 cases.</a> Obesity Surgery. 11, 276-280 (2001).</li><li>Lee, W. 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=Laparoscopic+Roux-en-Y+vs.+mini-gastric+bypass+for+the+treatment+of+morbid+obesity:+a+10-year+experience.">Laparoscopic Roux-en-Y vs. mini-gastric bypass for the treatment of morbid obesity: a 10-year experience.</a> Obesity Surgery. 22, 1827-1834 (2012).</li><li>Victorzon, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Single-anastomosis+gastric+bypass:+better,+faster,+and+safer?.">Single-anastomosis gastric bypass: better, faster, and safer?.</a> Scandinavia Journal of Surgery. 104, 48-53 (2015).</li><li>Magouliotis, D. E., Tasiopoulou, V. S., Tzovaras, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One+anastomosis+gastric+bypass+versus+Roux-en-Y+gastric+bypass+for+morbid+obesity:+a+meta-analysis.">One anastomosis gastric bypass versus Roux-en-Y gastric bypass for morbid obesity: a meta-analysis.</a> Clinical Obesity. 8, 159-169 (2018).</li><li>Seyfried, F., le Roux, C. W., Bueter, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lessons+learned+from+gastric+bypass+operations+in+rats.">Lessons learned from gastric bypass operations in rats.</a> Obesity Facts. 4 Suppl 1, 3-12 (2011).</li><li>Wang, F. G., Yu, Z. P., Yan, W. M., Yan, M., Song, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+safety+and+effectiveness+between+laparoscopic+mini-gastric+bypass+and+laparoscopic+sleeve+gastrectomy:+A+meta-analysis+and+systematic+review.">Comparison of safety and effectiveness between laparoscopic mini-gastric bypass and laparoscopic sleeve gastrectomy: A meta-analysis and systematic review.</a> Medicine (Baltimore). 96, e8924 (2017).</li><li>Hong, J., Park, S., Menzo, E. L., Rosenthal, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Midterm+outcomes+of+laparoscopic+sleeve+gastrectomy+as+a+stand-alone+procedure+in+super-obese+patients.">Midterm outcomes of laparoscopic sleeve gastrectomy as a stand-alone procedure in super-obese patients.</a> Surgery for Obesity and Related Disease. 14 (3), 297-303 (2017).</li><li>Abellan, I., 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+influence+of+the+percentage+of+the+common+limb+in+weight+loss+and+nutritional+alterations+after+laparoscopic+gastric+bypass.">The influence of the percentage of the common limb in weight loss and nutritional alterations after laparoscopic gastric bypass.</a> Surgery for Obesity Related Disease. 10, 829-833 (2014).</li><li>Nora, M., Morais, T., Almeida, R., Guimar&#227;es, M., Monteiro, M. 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The authors have nothing to disclose.

This protocol has the advantage of mimicking OAGB practiced routinely in humans. Its safety and reproducibility in rats have been demonstrated in clinical and metabolic results.
The anastomosis in this protocol poses a technical difficulty and is the main critical step. For this, it is necessary to use specific microsurgical tools, such as a microsurgery needle-holder or magnifying glasses. In order to realize a hermetic anastomosis without any stenosis, it is necessary to perform at least sev...

Morbid obesity is a major health issue in the western world, with increasing prevalence1. Bariatric surgery remains the only long-term effective therapy for morbid obesity2, with clear benefits on obesity-related comorbidities3. Roux-en-Y gastric bypass (RYGB) remains the gold standard as it is one of the oldest procedures and one of the most-performed worldwide with the longest follow-up4. OAGB is a more recent procedure first described in 2001 by Rutledge5. It has been described as an effective alternative to RYGB6 and has some advantages. Early data indicates a similar efficacy to RYGB with respect to weight-loss and the resolution of obesity-related comorbidities6,7. Furthermore, the risks of stenosis or leakage of the jejunojejunal anastomosis in RYGB are avoided, and the risk of an internal hernia may be lower than with RYGB8.
The physiological mechanisms underlying weight-loss after bariatric surgery remain controversial and can be difficult to study in humans9. Animal models are useful to understand how bariatric surgeries may impact glucose metabolism, neuroendocrine modifications, or satiety mechanisms. Comparative data between procedures are lacking and long-term effects of these surgeries need to be better understood10. It is not possible to fully standardize pre- and postoperative clinical care, and satisfactory follow-up can be difficult to achieve: some studies report loss-to-follow-up rates as high as 30% for the first year11.
The concept of gastric bypass is a combination of a restrictive procedure, due to the creation of a gastric pouch, and a moderate degree of malabsorption, resulting from the exclusion of the duodenum and the proximal jejunum from the gastrointestinal transit. Currently, limb length in bariatric surgery is still a matter of debate12,13. Available data show a high variability of procedures and no consensus has yet been reached on the optimal limb length for OAGB14,15. Nonetheless, many authors have reported a 200 cm BPL length as the standard for OAGB16,17,18. The mean length of the small bowel is about 700 cm19.
Several rodent models of RYGB have been developed worldwide20, with great variations in terms of pouch size, limb length, and the preservation of the vagal nerve. But very few authors reported a model of experimental OAGB; for this reason, theresearch team developed a model of OAGB in collaboration with bariatric surgeons. The rationale behind the development of the model was to mimic gastric bypass practiced in humans. The model incorporates the construction of a gastric pouch with the exclusion of the antrum and the body of the stomach. For it, the surgeon makes an ablation of the nonglandular stomach using a stapling device. Compared to a previous protocol20, the team decided to add a per-operative prophylactic antibiotic treatment in order to diminish the morbidity linked to gastrointestinal anastomosis, as is routine in human surgery21.
The rat limb length used in this model was chosen to reproduce the ratio between the BPL and the CL in humans. Preliminary measurements have shown the total small bowel length in rats to be between 90 and 120 cm22. Consequently, the length of the BPL chosen for OAGB was 35 cm. Furthermore, this model is practicable without making any vascular ligation, avoiding gastric pouch ischemia.

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	<tbody>
		<tr height="62">
			<td height="62" style="height:62px;width:223px;">High-Fat Diet, 45 % fat&#160;</td>
			<td style="width:73px;">Genestil, Royaucourt, France</td>
			<td style="width:123px;">C 1090-45</td>
			<td style="width:172px;">http://www.genestil.com/</td>
		</tr>
		<tr height="125">
			<td height="125" style="height:125px;">Metzenbaum Scissors</td>
			<td style="width:73px;">World Precision instrument, Sarasota, US</td>
			<td align="right">501739</td>
			<td>https://www.wpi-europe.com</td>
		</tr>
		<tr height="125">
			<td height="125" style="height:125px;">Dumont Tweezers</td>
			<td style="width:73px;">World Precision instrument, Sarasota, US</td>
			<td>14098</td>
			<td>https://www.wpi-europe.com</td>
		</tr>
		<tr height="125">
			<td height="125" style="height:125px;width:223px;">Iris Forceps</td>
			<td style="width:73px;">World Precision instrument, Sarasota, US</td>
			<td>15915</td>
			<td>https://www.wpi-europe.com</td>
		</tr>
		<tr height="125">
			<td height="125" style="height:125px;width:223px;">Iris Scissors 10cm</td>
			<td style="width:73px;">World Precision instrument, Sarasota, US</td>
			<td>14218</td>
			<td>https://www.wpi-europe.com</td>
		</tr>
		<tr height="125">
			<td height="125" style="height:125px;">Needle Holder</td>
			<td style="width:73px;">World Precision instrument, Sarasota, US</td>
			<td>14110</td>
			<td>https://www.wpi-europe.com</td>
		</tr>
		<tr height="125">
			<td height="125" style="height:125px;">Alm Self Retaining Retractor</td>
			<td style="width:73px;">World Precision instrument, Sarasota, US</td>
			<td>14240</td>
			<td>https://www.wpi-europe.com</td>
		</tr>
		<tr height="125">
			<td height="125" style="height:125px;">Baby Mixter Hemostatic Forceps,&#160; Right Angle</td>
			<td style="width:73px;">World Precision instrument, Sarasota, US</td>
			<td style="width:123px;">501240</td>
			<td>https://www.wpi-europe.com</td>
		</tr>
		<tr height="104">
			<td height="104" style="height:104px;">Non woven sterile swabs</td>
			<td style="width:73px;">LCH Medical Products, Paris, France</td>
			<td>SN40-0755</td>
			<td>www.lch-medical.com</td>
		</tr>
		<tr height="125">
			<td height="125" style="height:125px;width:223px;">Galilean Binocular Loupe 2.5x</td>
			<td style="width:73px;">World Precision instrument, Sarasota, US</td>
			<td style="width:123px;">504056</td>
			<td>https://www.wpi-europe.com</td>
		</tr>
		<tr height="104">
			<td height="104" style="height:104px;">Digestive thread: Isotactic polypropylene, monofil Prolene 7-0&#160;</td>
			<td style="width:73px;">Ethicon, Issy les&#160; Moulineaux, France</td>
			<td style="width:123px;">EH7813E</td>
			<td>www.ethicon.com</td>
		</tr>
		<tr height="83">
			<td height="83" style="height:83px;">Parietal thread : Coated Braided Polyester Ti-Cron 2-0</td>
			<td style="width:73px;">Covidien, Mannsfield, MA, USA</td>
			<td>3003-52</td>
			<td>www.covidien.com</td>
		</tr>
		<tr height="104">
			<td height="104" style="height:104px;">Cutaneous thread : Polyglactin, VICRYL RAPIDE 4-0&#160;</td>
			<td style="width:73px;">Ethicon, Issy les&#160; Moulineaux, France</td>
			<td>VR3100</td>
			<td>www.ethicon.com</td>
		</tr>
		<tr height="104">
			<td height="104" style="height:104px;">ETS-Flex 35- mm staple gun</td>
			<td style="width:73px;">Ethicon, Issy les&#160; Moulineaux, France</td>
			<td style="width:123px;">ATS45</td>
			<td>www.ethicon.com</td>
		</tr>
		<tr height="104">
			<td height="104" style="height:104px;">Proximate Reloadable Staplers</td>
			<td style="width:73px;">Ethicon, Issy les&#160; Moulineaux, France</td>
			<td>XR30V</td>
			<td>www.ethicon.com</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;">TA-DST 30mm-3.5mm</td>
			<td>Ethicon, Issy les&#160; Moulineaux, France</td>
			<td>TX30B</td>
			<td>www.ethicon.com</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Alcoholic 5% Betadine</td>
			<td>MEDA Pharma, Merignac, France</td>
			<td>41085</td>
			<td>www.medapharma.fr</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">LIDOCAINE AGUETTANT 20 mg/ml</td>
			<td>LABORATOIRE AGUETTANT, Lyon, France</td>
			<td>3400940000000.0</td>
			<td>https://www.aguettant.fr</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Penicillin G 5MUI</td>
			<td>Panpharma, Luitre, France</td>
			<td>3.40E+12</td>
			<td>https://www.panpharma.eu/fr</td>
		</tr>
		<tr height="62">
			<td height="62" style="height:62px;">Bionolyte G5 ; Sodium chloride 0.4%, glucose 5%, potassium chloride 0.2%)</td>
			<td style="width:73px;">Baxter, Maurepas, France</td>
			<td style="width:123px;"></td>
			<td></td>
		</tr>
		<tr height="62">
			<td height="62" style="height:62px;width:223px;">Liquid diet</td>
			<td style="width:73px;">Genestil, Royaucourt, France</td>
			<td style="width:123px;">C-0200T</td>
			<td>http://www.genestil.com/</td>
		</tr>
		<tr height="83">
			<td height="83" style="height:83px;width:223px;">Isoflurane 100%</td>
			<td style="width:73px;">Centravet, Plancoet, France</td>
			<td style="width:123px;">ISO007</td>
			<td>http://cooperative.centravet.net</td>
		</tr>
	</tbody>
</table>

one-anastomosis gastric bypass (oagb) in rats

The goal of this protocol is to set up a preclinical model of bariatric surgery and, more specifically, OAGB in obese rats. Based on this preclinical model, longitudinal studies can be carried out to provide an improved understanding of the mechanisms underlying the outcomes seen after bariatric surgery in humans. For this purpose, rats are operated on through a laparotomy under general anesthesia with isoflurane. First, the surgeon creates a long and tubular gastric pouch: after greater curve and hiatal dissection, the nonglandular stomach is stapled and removed. Then, the remaining stomach is also stapled in order to create a gastric tube and exclude the antrum of the stomach. After that, the surgeon performs a single end-to-side gastrojejunostomy 35 cm from the duodenojejunal angle. This limb length has been chosen in order to reproduce the same ratio between the biliopancreatic limb (BPL) and common limb (CL) length as in human bariatric surgery. The operation ends by aponeurotic and cutaneous closure. The early postoperative management consists of subcutaneous hydration, an intramuscular prophylactic antibiotic injection, a parietal injection of xylocaine, the administration of painkillers, and a progressive reintroduction of diet.

This protocol is reproducible and mimics OAGB as practiced on humans. The safety of this protocol is supported with published data23,24 with a low mortality rate between 12% and 25%. Different surgeons in the research team with a similar mortality rate have practiced this protocol.
Nonetheless, learning rodent surgery is complex, and the use of magnifying glasses is mand...

Watch this Scientific Journal Video about One-anastomosis Gastric Bypass OAGB in Rats at JoVE.com

One-anastomosis Gastric Bypass OAGB in Rats

This protocol is for the performance of one-anastomosis gastric bypass (OAGB) on rat. The operator performs a long and tubular-stapled gastric pouch followed by hand-sewn anastomosis. For this model, the operator reproduces the same ratio between biliopancreatic and common limb in humans; therefore, the biliopancreatic limb measures 35 cm.

One-anastomosis Gastric Bypass (OAGB) in Rats

The goal of this protocol is to set up a preclinical model of bariatric surgery and, more specifically, OAGB in obese rats. Based on this preclinical ...

one-anastomosis-gastric-bypass-oagb-in-rats

Research

JoVE Journal

Medicine

10.8K Views.  Universit	é Paris Diderot, Assistance Publique-Hôpitaux de Paris (AP-HP). This protocol is for the performance of one-anastomosis gastric bypass (OAGB) on rat. The operator performs a long and tubular-stapled gastric pouch followed by hand-sewn anastomosis. For this model, the operator reproduces the same ratio between biliopancreatic and common limb in humans; therefore, the biliopancreatic limb measures 35 cm. 

Video: One-anastomosis Gastric Bypass OAGB in Rats

Acute Myocardial Infarction in Rats

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular diseases. Animal models that mimic human cardiac disease, such as myocardial infarction (MI) and ischemia-reperfusion (IR) that induces heart failure as well as pressure-overload (transverse aortic constriction) that induces cardiac hypertrophy and heart failure (Goldman and Tarnavski), are useful models to study cardiovascular disease. In particular, myocardial ischemia (MI) is a leading cause for cardiovascular morbidity and mortality despite controlling certain risk factors such as arteriosclerosis and treatments via surgical intervention (Thygesen). Furthermore, an acute loss of the myocardium following myocardial ischemia (MI) results in increased loading conditions that induces ventricular remodeling of the infarcted border zone and the remote non-infarcted myocardium. Myocyte apoptosis, necrosis and the resultant increased hemodynamic load activate multiple biochemical intracellular signaling that initiates LV dilatation, hypertrophy, ventricular shape distortion, and collagen scar formation. This pathological remodeling and failure to normalize the increased wall stresses results in progressive dilatation, recruitment of the border zone myocardium into the scar, and eventually deterioration in myocardial contractile function (i.e. heart failure). The progression of LV dysfunction and heart failure in rats is similar to that observed in patients who sustain a large myocardial infarction, survive and subsequently develops heart failure (Goldman). The acute myocardial infarction (AMI) model in rats has been used to mimic human cardiovascular disease; specifically used to study cardiac signaling mechanisms associated with heart failure as well as to assess the contribution of therapeutic strategies for the treatment of heart failure. The method described in this report is the rat model of acute myocardial infarction (AMI). This model is also referred to as an acute ischemic cardiomyopathy or ischemia followed by reperfusion (IR); which is induced by an acute 30-minute period of ischemia by ligation of the left anterior descending artery (LAD) followed by reperfusion of the tissue by releasing the LAD ligation (Vasilyev and McConnell). This protocol will focus on assessment of the infarct size and the area-at-risk (AAR) by Evan's blue dye and triphenyl tetrazolium chloride (TTC) following 4-hours of reperfusion; additional comments toward the evaluation of cardiac function and remodeling by modifying the duration of reperfusion, is also presented. Overall, this AMI rat animal model is useful for studying the consequence of a myocardial infarction on cardiac pathophysiological and physiological function.

The rat model of acute myocardial infarction (AMI) is useful to study the consequence of a MI on cardiac pathophysiological and physiological function.

With heart failure leading the cause of death in the USA (Hunt), biomedical research is fundamental to advance medical treatments for cardiovascular ...

Roux-en-Y Gastric Bypass Operation in Rats

Currently, the most effective therapy for the treatment of morbid obesity to induce significant and maintained body weight loss with a proven mortality benefit is bariatric surgery1,2. Consequently, there has been a steady rise in the number of bariatric operations done worldwide in recent years with the Roux-en-Y gastric bypass (gastric bypass) being the most commonly performed operation3. Against this background, it is important to understand the physiological mechanisms by which gastric bypass induces and maintains body weight loss. These mechanisms are yet not fully understood, but may include reduced hunger and increased satiation4,5, increased energy expenditure6,7, altered preference for food high in fat and sugar8,9, altered salt and water handling of the kidney10 as well as alterations in gut microbiota11. Such changes seen after gastric bypass may at least partly stem from how the surgery alters the hormonal milieu because gastric bypass increases the postprandial release of peptide-YY (PYY) and glucagon-like-peptide-1 (GLP-1), hormones that are released by the gut in the presence of nutrients and that reduce eating12.
During the last two decades numerous studies using rats have been carried out to further investigate physiological changes after gastric bypass. The gastric bypass rat model has proven to be a valuable experimental tool not least as it closely mimics the time profile and magnitude of human weight loss, but also allows researchers to control and manipulate critical anatomic and physiologic factors including the use of appropriate controls. Consequently, there is a wide array of rat gastric bypass models available in the literature reviewed elsewhere in more detail 13-15. The description of the exact surgical technique of these models varies widely and differs e.g. in terms of pouch size, limb lengths, and the preservation of the vagal nerve. If reported, mortality rates seem to range from 0 to 35%15. Furthermore, surgery has been carried out almost exclusively in male rats of different strains and ages. Pre- and postoperative diets also varied significantly.
Technical and experimental variations in published gastric bypass rat models complicate the comparison and identification of potential physiological mechanisms involved in gastric bypass. There is no clear evidence that any of these models is superior, but there is an emerging need for standardization of the procedure to achieve consistent and comparable data. This article therefore aims to summarize and discuss technical and experimental details of our previously validated and published gastric bypass rat model.

Numerous studies using gastric bypass rat models have been recently conducted to uncover the underlying physiological mechanisms of Roux-en-Y gastric bypass operations. This article aims to demonstrate and discuss the technical and experimental details of our published gastric bypass rat model to understand advantages and limitations of this experimental tool.

Currently, the most effective therapy for the treatment of morbid obesity to induce significant and maintained body weight loss with a proven mortality ...

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.

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 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 ...

Intraoperative Gastroscopy for Tumor Localization in Laparoscopic Surgery for Gastric Adenocarcinoma

Determining resection margins for gastric cancer, which are not exposed to the serosal surface of the stomach, is the most important procedure during totally laparoscopic gastrectomy (TLG). The aim of this protocol is to introduce a procedure for intraoperative gastroscopy, in order to directly mark tumors during TLG for gastric cancer in the middle third of the stomach. Patients who were diagnosed with adenocarcinoma in the middle third of the stomach were enrolled in this case series. Before surgery, additional gastroscopy for tumor localization is not performed. Under general anesthesia, laparoscopic mobilization of the stomach is performed first. After the first portion of the duodenum is mobilized from the pancreas and clamped, the surgeon moves to the other side for the gastroscopic procedure. On the insertion of a gastroscope through the oral cavity into the stomach, 2 - 3 cc of indigo carmine is administered via an endoscopic injector into the gastric muscle layer at the proximal margin of the stomach. The location of stained serosa in the laparoscopic view is used to guide distal subtotal gastrectomy, however, total gastrectomy is performed if the tumor is too close to the esophagogastric junction. A specimen is sampled after distal gastrectomy to confirm sufficient length from resection margin to tumor before reconstruction. In our case series, all patients had tumor-free margins and required no additional resection. There was no morbidity related to the gastroscopic procedure, and the time required for the procedure has gradually decreased to about five minutes. Intraoperative gastroscopy for tumor localization is an accurate and tolerated method for gastric cancer patients undergoing totally laparoscopic distal gastrectomy.

In early gastric cancer, the aim of surgery is to precisely remove the distal stomach including the primary tumor. To do this, accurate localization of the tumor is crucial, especially in totally laparoscopic surgery. This protocol describes a procedure for intraoperative gastroscopy in totally laparoscopic subtotal gastrectomy.

Determining resection margins for gastric cancer, which are not exposed to the serosal surface of the stomach, is the most important procedure during ...

Vein Interposition Model: A Suitable Model to Study Bypass Graft Patency

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. Research models for bypass graft failure are essential for a better understanding of pathobiological and pathophysiological processes during graft patency loss. Large animal models, such as pigs or sheep, resemble human anatomical structures but require special facilities and equipment. This video describes a rat vein interposition model to investigate vein graft patency loss. Rats are inexpensive and easy to handle. Compared to mouse models, the convenient size of rats permits better operability and enables a sufficient amount of material to be obtained for further diverse analysis. In brief, the inferior epigastric vein of a donor rat is harvested and used to replace a segment of the femoral artery. Anastomosis is conducted via single stitches and sealed with fibrin glue. Graft patency can be monitored non-invasively using duplex sonography. Myointimal hyperplasia, which is the main cause for graft patency loss, develops progressively over time and can be calculated from histological cross sections.

This video demonstrates a model to study the development of myointimal hyperplasia after venous interposition surgery in rats.

Bypass grafting is an established treatment method for coronary artery disease. Graft patency continues to be the Achilles heel of saphenous vein grafts. ...

Techniques of Sleeve Gastrectomy and Modified Roux-en-Y Gastric Bypass in Mice

Obesity is a major public health issue, with a prevalence of 4 to 28% for men and 6.2 to 36.5% for women in Europe (from 2003 to 2008). Morbid obesity is frequently associated with metabolic complications, such as type 2 diabetes, hypertension, and dyslipidemia, reducing life expectancy and quality. In the absence of any effective noninvasive treatments, bariatric surgery is a valuable therapeutic option for patients with morbid obesity (body mass index (BMI) &#62;40 kg/m2), leading to long-term, sustained weight loss and improvements in metabolic complications. However, the underlying cellular and molecular mechanisms sustaining the beneficial effects of bariatric surgery are not yet fully understood. Due to the numerous genetically-modified strains available, the mouse model is the most convenient animal model to explore the molecular mechanisms behind the pleiotropic beneficial effects of bariatric surgeries. Here, we detailed the optimized healthcare methods and surgical protocols in mice for the two most widely-used bariatric surgeries: the sleeve gastrectomy and the modified Roux-en-Y gastric bypass. Deciphering the molecular mechanisms underlying the therapeutic effects of bariatric surgeries offers the promise of identifying new therapeutics targets.

Bariatric surgery is the most efficient way to reduce body weight and the deadly metabolic complications (diabetes, obesity, and dyslipidemia) frequently associated with morbid obesity. Mouse models of bariatric surgery represent a unique asset for deciphering molecular mechanisms behind the beneficial effects of these surgeries on diabetes, hypertension, and dyslipidemia.

Obesity is a major public health issue, with a prevalence of 4 to 28% for men and 6.2 to 36.5% for women in Europe (from 2003 to 2008). Morbid obesity is ...

Cardiopulmonary Bypass in a Mouse Model: A Novel Approach

As prolonged cardiopulmonary bypass becomes more essential during cardiac interventions, an increasing clinical demand arises for procedure optimization and for minimizing organ damage resulting from prolonged extracorporal circulation. The goal of this paper was to demonstrate a fully functional and clinically relevant model of cardiopulmonary bypass in a mouse. We report on the device design, perfusion circuit optimization, and microsurgical techniques. This model is an acute model, which is not compatible with survival due to the need for multiple blood drawings. Because of the range of tools available for mice (e.g., markers, knockouts, etc.), this model will facilitate investigation into the molecular mechanisms of organ damage and the effect of cardiopulmonary bypass in relation to other comorbidities.

This paper describes how to perform cardiopulmonary bypass in mice. This novel model will facilitate the investigation of the molecular mechanisms involved in organ damage.

As prolonged cardiopulmonary bypass becomes more essential during cardiac interventions, an increasing clinical demand arises for procedure optimization ...

Preparation of Decellularized Kidney Scaffolds in Rats

Tissue engineering is a cutting-edge discipline in biomedicine. Cell culture techniques can be applied for regeneration of functional tissues and organs to replace diseased or damaged organs. Scaffolds are needed to facilitate the generation of three-dimensional organs or tissues using differentiated stem cells in vivo. In this report, we describe a novel method for developing vascularized scaffolds using decellularized rat kidneys. Eight-week-old Sprague-Dawley rats were used in this study, and heparin was injected into the heart to facilitate flow into the renal vessels, allowing heparin to perfuse into the renal vessels. The abdominal cavity was opened, and the left kidney was collected. The collected kidneys were perfused for 9 h using detergents, such as Triton X-100 and sodium dodecyl sulfate, to decellularize the tissue. Decellularized kidney scaffolds were then gently washed with 1% penicillin/streptomycin and heparin to remove cellular debris and chemical residues. Transplantation of stem cells with the decellularized vascular scaffolds is expected to facilitate the generation of new organs. Thus, the vascularized scaffolds may provide a foundation for tissue engineering of organ grafts in the future.

This protocol introduces a method to develop a scaffold using decellularized rat kidneys. The protocol includes decellularization and recellularization processes to confirm bioavailability. Decellularization is performed using Triton X-100 and sodium dodecyl sulfate.

Tissue engineering is a cutting-edge discipline in biomedicine. Cell culture techniques can be applied for regeneration of functional tissues and organs ...

A Protocol for Roux-en-Y Gastric Bypass in Rats using Linear Staplers

Roux-en-Y gastric bypass (RYGB) is commonly performed for the treatment of severe obesity and type 2 diabetes. However, the mechanism of weight loss and metabolic changes are not well understood. Multiple factors are thought to play a role, including reduced caloric intake, decreased nutrient absorption, increased satiety, the release of satiety-promoting hormones, shifts in bile acid metabolism, and alterations in the gut microbiota.
The rat RYGB model presents an ideal framework to study these mechanisms. Prior work on mouse models have had high mortality rates, ranging from 17 to 52%, limiting their adoption. Rat models demonstrate more physiologic reserve to surgical stimulus and are technically easier to adopt as they allow for the use of surgical staplers. One challenge with surgical staplers, however, is that they often leave a large gastric pouch which is not representative of RYGB in humans. 
In this protocol, we present a RYGB protocol in rats that result in a small gastric pouch using surgical staplers. Utilizing two stapler fires which remove the forestomach of the rat, we obtain a smaller gastric pouch similar to that following a typical human RYGB. Surgical stapling also results in better hemostasis than sharp division. Additionally, the forestomach of the rat does not contain any glands and its removal should not alter the physiology of RYGB.
Weight loss and metabolic changes in the RYGB cohort were significant compared to the sham cohort, with significantly lower glucose tolerance at 14 weeks. Furthermore, this protocol has an excellent survival of 88.9% after RYGB. The skills described in this protocol can be acquired without previous microsurgical experience. Once mastered, this procedure will provide a reproducible tool for studying the mechanisms and effects of RYGB.

Roux-en-Y gastric bypass (RYGB) is performed to treat obesity and diabetes. However, the mechanisms underlying RYGB's efficacy are not fully understood, and studies are limited by technical difficulty leading to high mortality in animal models. This article provides instructions on how to perform RYGB in rats with high success rates.

Roux-en-Y gastric bypass (RYGB) is commonly performed for the treatment of severe obesity and type 2 diabetes. However, the mechanism of weight loss and ...