We thank Ethicon (Johnson and Johnson surgical technologies) for kindly providing the suture cord and surgical clips. This work was supported by grants from the NExT Talent Project, Universit&#233; de Nantes, CHU de Nantes.

This protocol has been approved by the local French ethical committee for animal experimentation (Comit&#233; d&#39;&#233;thique en exp&#233;rimentation animale; reference CEEA-PdL n 06).
1. Pre-operative preparation
<ol>
	<li>Add gel diet food to the normal diet 3 days before the surgery. Fast the mice 6 h before the surgery.</li>
	<li>Induce anesthesia with 5% isoflurane (1 L/min) in a dedicated chamber with oxygen (1 L/min). Inject the mice subcutaneously with buprenorphine (0.1 mg/kg), amoxicillin (15 mg/kg), metoclopramide (1 mg/kg), meloxicam (1 mg/kg)&#160;and iron (0.5 mg/kg).</li>
	<li>Shave the first 2/3 parts of the mouse&#39;s abdomen beginning from the xiphoid process using an electric razor. Disinfect the mouse&#39;s abdomen in two steps using an iodine polyvidone solution .</li>
	<li>Place the mouse supine on a dedicated heat pad covered with a clean underpad. Maintain anesthesia using a nose cone with 2%-2.5% isoflurane (0.4 L/min) with oxygen (0.4 L/min). Use a toe-pinch test to confirm the depth of anesthetization.</li>
	<li>Cover the mouse in a sterilized plastic wrap. In order to apply hyperextension on the mouse&#39;s abdomen, fix the lower paw and use a 1 mL syringe or equivalent placed behind the mouse&#39;s back. Cut an&#160;opening in a sterile compress with the size of the future incision,&#160;and use it as an operating field to cover the mouse. The general installation is shown in Figure 2A.</li>
	<li>Before the surgery, use a face mask, a scrub cap, and sterilized gloves. Use sterilized instruments for the surgery.</li>
</ol>
2. The SADI-S protocol
<ol>
	<li>Median laparotomy
	<ol>
		<li>Under a binocular microscope (8x magnification), perform a median laparotomy with scissors or a scalpel by opening the abdominal skin from the xiphoid process to the middle of the abdomen. Ensure that the xiphoid process and the musculoaponeurotic layer are visible (Figure 2B). 
		NOTE: Administer bupivacaine (3 mg/kg) subcutaneously at the surgical&#160;site 5 mins before making the skin incision.</li>
		<li>Open the abdominal wall along the linea alba with scissors between the abdominal muscles. Be careful not to enter the thoracic cavity (Figure 2C).</li>
	</ol>
	</li>
	<li>Duodenal exclusion
	<ol>
		<li>Gently mobilize the duodenum from the abdominal cavity using a moistened cotton swab to see its anterior and posterior sides. Localize the main bile duct, which is immediately visible under the binocular microscope on the posterior side of the lesser omentum and the duodenum (Figure 3A, black arrows).</li>
		<li>Proximally from the main bile duct, visualize an area between the duodenal arteries under the binocular microscope (Figure 3A,B, blue dotted circles). Penetrate this area using curved micro forceps from one side of the duodenum to the other, and perform a duodenal ligation between the arteries using a 6-0 non-absorbable suture (Figure 3C-E). Be careful not to ligate the branches of the duodenal arteries.</li>
	</ol>
	</li>
	<li>Sleeve gastrectomy
	<ol>
		<li>Mobilize the stomach from the abdominal cavity using a moistened cotton swab and a non-traumatic clamp. Separate the stomach from the surrounding organs using micro scissors: separate the greater omentum, cut the short gastric arteries (branch of the splenic artery) between the stomach and the spleen, and the lipoma linking the stomach to the lower part of the esophagus (Figure 4A,B).</li>
		<li>Using micro scissors, perform a 5 mm gastrotomy by opening the fundus and remove the residual food using a cotton swab (Figure 4C, arrow). Rinse the gastrotomy site with sterile saline solution (37 &#176;C) to avoid contamination from the removed gastric contents.&#160;</li>
		<li>Apply surgical clips (medium size, 5.6 mm) along the stomach&#39;s greater curvature to exclude approximately 80% of the stomach. Two clips are sufficient. Remove the excluded stomach by cutting it with micro scissors (Figure 4D-G).</li>
		<li>Anchor the surgical clips to ascertain impermeability by performing a running suture (8-0) from the beginning to the end of the stomach resection (Figure 4H).</li>
	</ol>
	</li>
	<li>Duodeno-ileal anastomosis
	<ol>
		<li>Under the binocular microscope, visualize the last ileal loop, which is situated just before the caecum (Figure 5A). Gently mobilize the small intestine outside the abdominal cavity from the last ileal loop. Lay out the small bowel, as displayed in Figure 5B, so that the last ileal loop is located on the left side. Using a previously sized suture cord, measure 10 cm (approximately 1/3 of the total length of the small bowel) from the last ileal loop; this will be the site of the future anastomosis.</li>
		<li>In order to ensure that the future biliary limb comes to the anastomosis site from its left side, make a large loop of the small intestine around the site of the future anastomosis. Using micro scissors, perform a 4 mm enterotomy by opening the small bowel at this point (Figure 5C-E).&#160;Rinse the enterotomy site with&#160;sterile saline solution (37 &#176;C) to avoid contamination.</li>
		<li>Perform a 4 mm enterotomy on the excluded part of the duodenum, immediately after the pylorus, between the stomach and the ligation performed in step 2.2.2 (Figure 5F). Place an absorbable 5 mm x 5 mm hemostatic collagen compress to favor homeostasis.</li>
		<li>Using a non-absorbable 8-0 suture, perform a side-to-side duodeno-ileal anastomosis. Begin with the posterior side anastomosis, followed by the anterior side anastomosis (Figure 5G-I).</li>
	</ol>
	</li>
	<li>Abdominal closure
	<ol>
		<li>Display the small bowel in the abdominal cavity so that the biliary limb comes to the anastomosis from the superior-left side of the abdomen and the common limb falls to the lower part of the abdomen. 
		NOTE: Lavage the abdomen three times with approximately 5 mL of sterile 0.9% saline solution (37 &#176;C). Then, suction the fluid from the abdomen to remove residual gastrointestinal fluid and digested food to avoid bacterial infection and subsequent abdominal inflammation.&#160;</li>
		<li>Rehydrate the mouse with 500 &#181;L of 37 &#176;C saline solution by applying it directly into the abdominal cavity using a 1 mL syringe.</li>
		<li>Close the musculoaponeurotic layer using a single 6-0 non-absorbable running suture. Close the abdominal skin using 6-0 non-absorbable separated sutures (Figure 5J,K).</li>
	</ol>
	</li>
</ol>
3. General postoperative care
<ol>
	<li>After stopping the isoflurane, let the mouse wake on the heat pad under 0.4 L/min O2 insufflated with the nose mask. When fully awakened, which can be ensured by complete motor recuperation, place the mouse alone in a cage in a 30 &#176;C incubator. Leave the mouse in the 30 &#176;C incubator for 5 days (no specific condition for gas or humidity). 
	NOTE: The cage should be warmed beforehand.</li>
	<li>Allow free access to water immediately after surgery. Add vitamin supplements, including vitamins B1, B9, B12, and liposoluble vitamins (A, D, E, K), to water (800 mg/180 mL of water) until the end of the protocol.</li>
	<li>Maintain analgesia by subcutaneous buprenorphine injections (0.1 mg/kg) twice a day from day 1 to day 3, once a day afterward until day 5. Continue amoxicillin (15 mg/kg), meloxicam (1 mg/kg) and metoclopramide (1 mg/kg) subcutaneous injections once a day until day 3. Provide subcutaneous injections of iron (0.5 mg/kg) once a day until the end of the protocol.</li>
</ol>
4. General measurements and euthanasia
<ol>
	<li>Weigh the mice every day until postoperative day 5. Then weigh on day 7, and then weekly.</li>
	<li>To measure daily food intake, place one mouse per cage. Place a known weight of a solid diet and measure the weight of the solid diet remaining after 24 h. Measure food intake on day 3, 4, 5, 7, and then weekly.</li>
	<li>Euthanize the mice by cervical dislocation under general anesthesia (5% isoflurane (1 L/min) with oxygen (1 L/min)) with subcutaneous injection of buprenorphine (0.1 mg/kg) after cardiac left atrium incision for blood sampling (500 to 600 &#181;L of blood).</li>
	<li>Measure the blood hemoglobin concentration using an automatic hematology analyzer requiring 20 &#956;L of blood.</li>
</ol>

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L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prevalence+of+obesity+and+trends+in+the+distribution+of+body+mass+index+among+US+adults,+1999-2010.">Prevalence of obesity and trends in the distribution of body mass index among US adults, 1999-2010.</a> JAMA. 307 (5), 491-497 (2012).</li><li>Sj&#246;str&#246;m, 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=Association+of+bariatric+surgery+with+long-term+remission+of+type+2+diabetes+and+with+microvascular+and+macrovascular+complications.">Association of bariatric surgery with long-term remission of type 2 diabetes and with microvascular and macrovascular complications.</a> JAMA. 311 (22), 2297-2304 (2014).</li><li>Dyson, 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=Hepatocellular+cancer:+the+impact+of+obesity,+type+2+diabetes+and+a+multidisciplinary+team.">Hepatocellular cancer: the impact of obesity, type 2 diabetes and a multidisciplinary team.</a> Journal of Hepatology. 60 (1), 110-117 (2014).</li><li>S&#225;nchez-Pernaute, A., 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=Proximal+duodenal-ileal+end-to-side+bypass+with+sleeve+gastrectomy:+proposed+technique.">Proximal duodenal-ileal end-to-side bypass with sleeve gastrectomy: proposed technique.</a> Obesity Surgery. 17 (12), 1614-1618 (2007).</li><li>Himpens, J., Verbrugghe, A., Cadi&#232;re, G. 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Claire Blanchard has been paid by Medtronic to provide courses of clinical immersions.

Bariatric surgeries, whose techniques are constantly evolving, appear to be currently the most effective treatment for obesity and associated metabolic comorbidities3,19,20. The SADI-S procedure, firstly described in 20074, is a promising procedure associated with greater metabolic effects than other malabsorptive surgeries. Animal models, particularly mice that allow the rapid generation of genetically modified models, are strongly needed to fully understand the mechanisms underlying these improvements. Here we describe a reliable and reproductible model of SADI-S in mice.
The first critical step of the SADI-S procedure is the exclusion of the duodenum, allowing only the bile and pancreatic secretions to travel into the duodenum and the first two-thirds of the small intestine. In humans, the duodenum is cut, allowing end-to-side duodeno-ileal anastomosis4. In the rat SADI-S model described by Montana et al.15, exclusion of the duodenum by a non-absorbable suture or surgical clamp is imperfect in a few cases, resulting in duodenal repermeabilization (i.e., reintroduction of the bolus into the original digestive tract). However, a section of the duodenum followed by end-to-side anastomosis is difficult to transpose in mice, leading us to prefer duodenum ligation. Indeed, the short length of the duodenal vessels limits the duodenal mobilization if the duodenum is completely transected, making it difficult to perform termino-lateral anastomosis. Initial experiments (data not shown) showed high mortality, even with trained and skilled experimenters. Only one case of repermeabilization has been observed in this study. Special attention must be given to the duodenal arteries during this step. Circumferential devascularization of the duodenum leads to death in all cases, but mice can be expected to recover from a small devascularized area caused by distal vessel ligation. The anatomical variability of the duodenal vascularization in mice prevents us from describing a constant localization to perform this exclusion. However, 0.5 cm of the duodenum after the pylorus must be available to permit the end-to-side anastomosis.
Another critical step when performing the anastomosis is to display the bowel in a way that the biliary limb comes to the site of the duodeno-ileal anastomosis from the left side. Otherwise, the food will oppose the bile flow, causing the biliary limb to distend, the bile to diffuse to the abdominal cavity, and the mice to die from biliary peritonitis around postoperative day 2. This condition resembling an afferent loop syndrome21 can be prevented by performing a loop of the small intestine centered on the anastomosed zone of the ileum. This is necessary because, contrary to humans, the caecum is positioned on the left side of the abdomen in 80% of cases in mice22.
In humans, the common limb measures approximately 250 cm to limit malnutrition, which corresponds to approximately one-third of the total length of the small bowel23. Prior to surgeries, we measured the total length of the small intestine of the mouse model under similar feeding conditions (C57BL6/J under a chow diet) to determine the size of the common limb. As the small bowel length could vary between mice of different genetic backgrounds or following different feeding conditions, we strongly encourage future surgeons to perform a pilot study to measure the bowel size. The same size should be used for each mouse of the same background, as systematically exteriorizing the totality of the bowel for a complete measurement during surgery should be avoided (as there is increased risk of dehydration, hypothermia, and visceral injury).
The sleeve gastrectomy is part of the original SADI-S technique, allowing restriction in addition to malabsorption4. Several models of sleeve gastrectomy in mice are available in the literature12,24,25,26. The use of surgical clips instead of sutures alone allows a significant gain of time24 and reduces blood loss, two necessary conditions for surgical success. Anchoring the surgical clip using a 8-0 running suture prevented intragastric clip migration in all cases in our experiment. By removing the cardiac region, this technique allows the removal of about 80% of the stomach12. In this model, however, SADI-S was associated with overfeeding compared with the sham control mice, aiming (probably) to compensate for the malabsorption caused by bowel derivation. Other models suggested that sleeve gastrectomy in mice preferentially modified the food intake behavior instead of the absolute quantity of food ingested per day in the long term11,26. This limited restrictive effect is a limitation of this model.
This protocol has a 75% survival rate. It is worth noting that the 5-day survival was a strong predictor for long-term survival, as no late death occurred during our experiment. No anastomotic stenosis was observed. However, reaching this survival rate required at least 3 weeks of intensive microsurgical training by an experimenter specialized in animal surgery; the increased survival over time correlated with a decreased operating time. Perioperative care is one of the keys to the success of this technique. A strict analgesic protocol is needed in addition to systematic antibiotic-based therapy, and alimentation must be introduced progressively, using only a gel diet for 3 days. As previously described12, supplementation with vitamins B1, B9, B12, and liposoluble vitamins (A, D, E, K) is necessary after malabsorptive surgery, as well as iron supplementation, which prevented anemia in our experiment, but has not been described for the SADI-S model yet15.
In conclusion, SADI-S can be transposed successfully in mice, with a few modifications from its description in humans. This technique requires training and a strict perioperative protocol. Adapting this surgery to mice could allow for a better understanding of the mechanisms underlying the strong metabolic effect of this promising procedure in comparison with former models and could help to better define its surgical indications.

Obesity is an emerging and endemic situation with increasing prevalence, affecting approximately 1 in 20 adults worldwide1. Bariatric surgery has become the most effective treatment option for the affected adults in recent years, improving both weight loss and metabolic disorders2,3, with variable results depending on the type of surgical procedure used.
There are two main mechanisms that are implicated in the effects of the bariatric procedures: restriction that aims to increase satiety (such as in the sleeve gastrectomy (SG) where 80% of the stomach is removed), and malabsorption. Among the procedures that imply both restriction and malabsorption, the single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) has been proposed as an alternative to the Roux-en-Y gastric bypass (RYGB), in which a weight regain is observed in approximately 20% patients4,5. In this technique, a sleeve gastrectomy is associated with a small bowel rearrangment, dividing it into a biliary and a short common limb (one-third of the total small bowel length) (Figure 1A). Technically, the SADI-S has the advantage over the RYGB of requiring only a single anastomosis, reducing the operation time by approximately 30%. In addition, this method preserves the pylorus, which helps to reduce the risk of peptic ulcer disease and limits anastomotic leakage. The SADI-S is also associated with a high rate of metabolic improvement, strongly favoring its use during the last few years6,7.
Since metabolic effects have become increasingly foundational to bariatric procedures, elucidating their mechanisms seems crucial. Therefore, the use of animal models for bariatric procedures is of utmost importance to better understand their metabolic effects and the cellular and molecular pathways involved8. These models contributed, for example, to a better understanding of the change in food intake after SG or RYGB in a controlled environment9 and to the study of glucose or cholesterol fluxes through the intestinal barrier10,11; these informations are rarely available in clinical studies. This knowledge could help to define their optimal surgical indications. We previously described mouse models of SG and RYGB12. However, despite its promising results in clinical practice, the SADI-S has only been developed and described in rats13,14,15. However, given its genetic malleability, the mouse model has been useful in the past to study the various metabolic effects of such procedures16,17,18, and a SADI-S mouse model could be useful to evaluate effects of SADI-S despite the technical difficulty.
In this article, we describe the adaptation of the SADI-S procedure in mice (Figure 1B) in a reproducible manner. Special attention is given to the description of perioperative care.

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single-anastomosis duodeno-ileal bypass with sleeve gastrectomy model in mice

Obesity is a major health issue worldwide. As a response, bariatric surgeries have emerged to treat obesity and its related comorbidities (e.g., diabetes mellitus, dyslipidemia, non-alcoholic steatohepatitis, cardiovascular events, and cancers) through restrictive and malabsorptive mechanisms. Understanding the mechanisms by which these procedures allow such improvements often require their transposition into animals, especially in mice, because of the ease of generating genetically modified animals. Recently, the single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) has emerged as a procedure that uses both restrictive and malabsorptive effects, which is being used as an alternative to gastric bypass in case of major obesity. Thus far, this procedure has been associated with strong metabolic improvements, which has led to a marked increase in its use in daily clinical practice. However, the mechanisms underlying these metabolic effects have been poorly studied as a result of a lack of animal models. In this article, we present a reliable and reproducible model of SADI-S in mice, with a special focus on perioperative management. The description and use of this new rodent model will be helpful for the scientific community to better understand the molecular, metabolic, and structural changes induced by the SADI-S and to better define the surgical indications for clinical practice.

Learning curve 
The learning curve for this model is displayed in Figure 6. A progressive decrease in the operating time is observed, reaching approximately 60 min of surgery after 4 weeks of intensive training (Figure 6A). The 5-day postoperative survival also improved with time, reaching 77% during regular practice (Figure 6B). The most frequent causes of mortality were anastomotic leaks and an afferent loop syndrome resulting in biliary peritonitis. We observed no death later in the first month with the technique described in this manuscript. Of note, previous experiments performed without anchoring surgical clips with running sutures led to clip migration in two-thirds of the cases, resulting in one death by small bowel occlusion at 31 days. These results emphasize that mastering this model requires intensive training.
General parameters 
Mice with a C57BL6/J background were randomly assigned to the SADI-S group (n = 9; 5 males, 4 females) and the sham control group (n = 4; 2 males, 2 females). Between the SADI-S mice and the sham mice, the mean pre-operative weight (27.9 g &#177; 0.98 g vs. 28.5 g &#177; 2.4 g) and age (14.8 weeks &#177; 7.2 weeks vs. 18.7 weeks &#177; 10.3 weeks) were not significantly different. One mouse died after SADI-S at postoperative day 4 from an anastomotic leak and was therefore excluded from the following analysis. SADI-S mice experienced significant weight loss in comparison with the sham control mice from the fourth postoperative day: 21.7 g &#177; 1.6 g versus 29.0 g &#177; 0.7 g (p = 0.0081) (Figure 7A). Daily food intake (14 days) significantly increased in SADI-S mice (4.4 g &#177; 0.1 vs. 2.9 g &#177; 0.6 g per day, p = 0.027) (Figure 7B).
Mice were sacrificed 28 days after surgery. One mouse in the SADI-S group, which did not display significant weight loss, appeared to have duodenal repermeabilization. No such event was observed in the other 7 mice. As displayed in Figure 7C, the hemoglobin concentration was not significantly different from the sham control mice in the SADI-S group after iron supplementation.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/64610/64610fig01.jpg" /> 
Figure 1: Representation of single anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S). (A) In humans, the duodenum is cut proximally from the main bile duct. A latero-terminal duodeno-ileal anastomosis is performed with the remnant duodenum, defining a biliary limb (before the anastomosis) and a common limb which measures one-third of the total length of the small bowel (after the anastomosis). (B) In mice, the duodenum is excluded by ligature proximally to the main bile duct, and a latero-lateral duodeno-ileal anastomosis is performed. The figure was created with BioRender.com and Servier Medical Art templates which are licensed under a Creative Commons Attribution 3.0 Unported License; https://smart.servier.com/.&#160;<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/64610/64610fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/64610/64610fig02.jpg" /> 
Figure 2: Mouse installation for SADI-S. (A) General installation. (B) Skin opening from the xyphoid process (sternal base) to the middle of the abdomen. (C) Musculo-aponeurotic layer and peritoneal opening. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/64610/64610fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/64610/64610fig03.jpg" /> 
Figure 3: Duodenal exclusion. (A) Avascular window between duodenal arteries (blue dotted circle) on the posterior side of the duodenum, localized before the main bile duct (black arrows). (B) Avascular window between duodenal arteries (blue dotted circle) on the anterior side of the duodenum. (C,D) Duodenal exclusion using 6-0 non-absorbable suture. (E) Final view of excluded duodenum. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/64610/64610fig03large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/64610/64610fig04.jpg" /> 
Figure 4: Sleeve gastrectomy. (A) Greater omentum removal. (B) Incision of short gastric arteries. (C) Initial gastrotomy (blue arrow). (D-G) Stomach cardiac region removal using two surgical clips. (H) Surgical clips anchoring using 6-0 non-absorbable suture. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/64610/64610fig04large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/64610/64610fig05.jpg" /> 
Figure 5: Duodeno-ileal anastomosis. (A) Identification of the last ileal loop (asterisk). (B) Count 10 cm (one-third of the total length of the small bowel) from the last ileal loop (asterisk) to the site of the future anastomosis (blue arrow). (C,D) Small bowel rotation around the site of the future anastomosis (blue arrow). (E) Ileal enterotomy. (F) Duodenotomy (white arrow). (G-I) Side-to-side anastomosis in two layers between the duodenotomy (white arrow) and the ileal enterotomy (blue arrow). (J) Musculo-aponeurotic layer closure. (K) Skin closure. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/64610/64610fig05large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/64610/64610fig06.jpg" /> 
Figure 6: The SADI-S procedure learning curve. (A) The effect of training on the duration of the operation. Data are presented as the mean value &#177; SEM. (B) The effect of training on five-day survival. Data are presented as percentages. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/64610/64610fig06large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/64610/64610fig07.jpg" /> 
Figure 7: General parameters after SADI-S. (A) Postoperative body weight, (B) food intake measured for 24 h at day 14, and (C) blood hemoglobin concentrations were compared between SADI-S and sham control mice. Data are presented as the mean&#160;&#177; SEM. Statistical comparisons were made with two-way ANOVA (with Sidak&#39;s multiple comparisons test) or Mann-Whitney non-parametric tests. * p &#60; 0.05; ** p &#60; 0.01. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/64610/64610fig07large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Single-Anastomosis Duodeno-Ileal Bypass with Sleeve Gastrectomy Model in Mice at JoVE.com

Single-Anastomosis Duodeno-Ileal Bypass with Sleeve Gastrectomy Model in Mice

Single-anastomosis duodeno-ileal bypass (SADI-S) is an emerging bariatric procedure with important metabolic effects. In this article, we present a reliable and reproducible model of SADI-S in mice.

Obesity is a major health issue worldwide. As a response, bariatric surgeries have emerged to treat obesity and its related comorbidities (e.g., diabetes ...

single-anastomosis-duodeno-ileal-bypass-with-sleeve-gastrectomy-model

Nanyang Technological University

Research

JoVE Journal

Medicine

1.4K Views.  Nantes Université. Single-anastomosis duodeno-ileal bypass (SADI-S) is an emerging bariatric procedure with important metabolic effects. In this article, we present a reliable and reproducible model of SADI-S in mice.

Video: Single-Anastomosis Duodeno-Ileal Bypass with Sleeve Gastrectomy Model in Mice

Modeling Stroke in Mice - Middle Cerebral Artery Occlusion with the Filament Model

Stroke is among the most frequent causes of death and adult disability, especially in highly developed countries. However, treatment options to date are very limited. To meet the need for novel therapeutic approaches, experimental stroke research frequently employs rodent models of focal cerebral ischaemia. Most researchers use permanent or transient occlusion of the middle cerebral artery (MCA) in mice or rats.
Proximal occlusion of the middle cerebral artery (MCA) via the intraluminal suture technique (so called filament or suture model) is probably the most frequently used model in experimental stroke research. The intraluminal MCAO model offers the advantage of inducing reproducible transient or permanent ischaemia of the MCA territory in a relatively non-invasive manner. Intraluminal approaches interrupt the blood flow of the entire territory of this artery. Filament occlusion thus arrests flow proximal to the lenticulo-striate arteries, which supply the basal ganglia. Filament occlusion of the MCA results in reproducible lesions in the cortex and striatum and can be either permanent or transient. In contrast, models inducing distal (to the branching of the lenticulo-striate arteries) MCA occlusion typically spare the striatum and primarily involve the neocortex. In addition these models do require craniectomy. In the model demonstrated in this article, a silicon coated filament is introduced into the common carotid artery and advanced along the internal carotid artery into the Circle of Willis, where it blocks the origin of the middle cerebral artery. In patients, occlusions of the middle cerebral artery are among the most common causes of ischaemic stroke. Since varying ischemic intervals can be chosen freely in this model depending on the time point of reperfusion, ischaemic lesions with varying degrees of severity can be produced. Reperfusion by removal of the occluding filament at least partially models the restoration of blood flow after spontaneous or therapeutic (tPA) lysis of a thromboembolic clot in humans.
In this video we will present the basic technique as well as the major pitfalls and confounders which may limit the predictive value of this model.

Filamentous occlusion of the Middle cerebral artery is a common model for studying ischemic stroke in mice.

Stroke is among the most frequent causes of death and adult disability, especially in highly developed countries. However, treatment options to date are ...

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 ...

A Repetitive Concussive Head Injury Model in Mice

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of knowledge on the injury and its effects. To develop a better understanding of concussions, animals are often used because they provide a controlled, rigorous, and efficient model. Studies have adapted traditional animal models to perform mTBI to stimulate mild injury severity by changing the injury parameters. These models have been used because they can produce morphologically similar brain injuries to the clinical condition and provide a spectrum of injury severities. However, they are limited in their ability to present the identical features of injuries in patients. Using a traditional impact system, a repetitive concussive injury (rCHI) model can induce mild to moderate human-like concussion. The injury degree can be determined by measuring the period of loss of consciousness (LOC) with a sign of a transient termination of breathing. The rCHI model is beneficial to use for its accuracy and simplicity in determining mTBI effects and potential treatments.

Concussion presents the most common type of traumatic brain injury. Therefore, a repetitive concussive animal model, which replicates the important features of an injury in patients, may provide a means to study concussion in a rigorous, controlled, and efficient manner.

Despite the concussion/ mild traumatic brain injury (mTBI) being the most frequent occurrence of traumatic brain injury, there is still a lack of ...

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 ...

Using the Sleeve Technique in a Mouse Model of Aortic Transplantation - An Instructional Video

Orthotopic aortic transplantation using the sleeve technique reduces injury to the aorta with failure rate of only 10-20%. The time to anastomose the aorta in mice using the sleeve method was short and easy averaging 20 min, permitting studies of iso/allo grafts. The following article describes the aortic transplantation procedure used in our laboratory. The mice were anesthetized with a mixture of 1.5% volume isoflurane and 100% oxygen through a face mask. At this point, the segment of the aorta between the renal arteries and its bifurcation was separated from the vena cava, freely prepared and clampedat the proximal and distal segments with a single silk suture. Prior to the removal of the aorta, a saline solution containing heparin was injected into the inferior vena cava. Then the aorta was cut between the clamps and a saline heparin solution was used to flush the lumen. The sleeve technique with monofilament sutures was used in order to transplant the abdominal aorta in the orthotopic position.

We present an orthotopic aortic transplantation model using the sleeve technique in mice. It is a very rapid anastomosis method, which can be employed in studies of vascular disease.

Orthotopic aortic transplantation using the sleeve technique reduces injury to the aorta with failure rate of only 10-20%. The time to anastomose the ...

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 ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

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.

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.

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 ...

Sleeve Gastrectomy in Mice using Surgical Clips

The number of people who are overweight and obese is continually increasing both in the adult and adolescent populations. This coincides with the increased universal phenomenon of type 2 diabetes (T2D) and other metabolic problems. Bariatric surgery, such as SG, is currently one of the most effective and commonly used long-term treatment for obesity and T2D, but the association between them is not completely explored yet. The mechanisms underlying the outcomes seen after bariatric surgery in humans can be investigated based on preclinical animal studies. The SG reduces body weight, glucose levels and many metabolic parameters, and is easy to perform with a low incidence of complications. The goal of this work is to provide a simple method and an uncomplicated preclinical model of bariatric surgery in animals for researchers.

The prevalence of diabetes and obesity is continuously increasing worldwide. The mechanisms between diabetes, obesity and their associated mortality and co-morbidities need to be further investigated. Here, we present a protocol for sleeve gastrectomy (SG) in animals as an uncomplicated preclinical model of bariatric surgery.