This research was supported by NIH/NCI R21CA195002-01A1, The President&#39;s Council of Cornell Women and the SUNY Graduate Diversity Fellowship. Dr. Cummings&#39; laboratory also received funding during the project period from the Cornell Comparative Cancer Biology Training Program and Eli Lilly and Company.

All experimental protocols have been approved by the Cornell University Institutional Animal Care and Use Committee.
1. Pre-surgical Preparation
NOTE: Study mice are typically on a C57BL diet-induced obese background to make studies translationally relevant to human obesity and insulin resistance. Male and female mice may be studied as described in the subsequent steps.
<ol>
	<li>At an age of 2 months, place mice on a 45% or 60% high fat diet for 2 months (see <st...

<ol>
	<li>Buchwald, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bariatric+surgery:+a+systematic+review+and+meta-analysis.">Bariatric surgery: a systematic review and meta-analysis.</a> JAMA. 292 (14), 1724-1737 (2004).</li><li>Wadden, T. A., Butryn, M. L., Byrne, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficacy+of+lifestyle+modification+for+long-term+weight+control.">Efficacy of lifestyle modification for long-term weight control.</a> Obes Res. 12, 151s-162s (2004).</li><li>Yanovski, S. Z., Yanovski, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Obesity.">Obesity.</a> N Engl J Med. 346 (8), 591-602 (2002).</li><li>Abbatini, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Long-term+effects+of+laparoscopic+sleeve+gastrectomy,+gastric+bypass,+and+adjustable+gastric+banding+on+type+2+diabetes.">Long-term effects of laparoscopic sleeve gastrectomy, gastric bypass, and adjustable gastric banding on type 2 diabetes.</a> Surg Endosc. 24 (5), 1005-1010 (2010).</li><li>Sjostrom, 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=Effects+of+bariatric+surgery+on+mortality+in+Swedish+obese+subjects.">Effects of bariatric surgery on mortality in Swedish obese subjects.</a> N Engl J Med. 357 (8), 741-752 (2007).</li><li>Adams, T. D., 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=Cancer+incidence+and+mortality+after+gastric+bypass+surgery.">Cancer incidence and mortality after gastric bypass surgery.</a> Obesity (Silver Spring). 17 (4), 796-802 (2009).</li><li>Vest, A. R., Heneghan, H. M., Schauer, P. R., Young, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surgical+management+of+obesity+and+the+relationship+to+cardiovascular+disease.">Surgical management of obesity and the relationship to cardiovascular disease.</a> Circulation. 127 (8), 945-959 (2013).</li><li>Ahmed, A. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laparoscopic+Roux-en-Y+gastric+bypass+and+its+early+effect+on+blood+pressure.">Laparoscopic Roux-en-Y gastric bypass and its early effect on blood pressure.</a> Obes Surg. 19 (7), 845-849 (2009).</li><li>Pories, 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=Who+would+have+thought+it?+An+operation+proves+to+be+the+most+effective+therapy+for+adult-onset+diabetes+mellitus.">Who would have thought it? An operation proves to be the most effective therapy for adult-onset diabetes mellitus.</a> Ann Surg. 222 (3), 339-350 (1995).</li><li>Garibay, D., 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=beta-Cell+Glucagon-Like+Peptide-1+Receptor+Contributes+to+Improved+Glucose+Tolerance+After+Vertical+Sleeve+Gastrectomy.">beta-Cell Glucagon-Like Peptide-1 Receptor Contributes to Improved Glucose Tolerance After Vertical Sleeve Gastrectomy.</a> Endocrinology. 157 (9), 3405-3409 (2016).</li><li>McGavigan, A. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TGR5+contributes+to+glucoregulatory+improvements+after+vertical+sleeve+gastrectomy+in+mice.">TGR5 contributes to glucoregulatory improvements after vertical sleeve gastrectomy in mice.</a> Gut. 66 (2), 226-234 (2017).</li><li>McGavigan, A. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vertical+sleeve+gastrectomy+reduces+blood+pressure+and+hypothalamic+endoplasmic+reticulum+stress+in+mice.">Vertical sleeve gastrectomy reduces blood pressure and hypothalamic endoplasmic reticulum stress in mice.</a> Dis Model Mech. 10 (3), 235-243 (2017).</li><li>Esteban Varela, J., Nguyen, N. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laparoscopic+sleeve+gastrectomy+leads+the+U.S.+utilization+of+bariatric+surgery+at+academic+medical+centers.">Laparoscopic sleeve gastrectomy leads the U.S. utilization of bariatric surgery at academic medical centers.</a> Surg Obes Relat Dis. 11 (5), 987-990 (2015).</li><li>Laferrere, B., 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=Effect+of+weight+loss+by+gastric+bypass+surgery+versus+hypocaloric+diet+on+glucose+and+incretin+levels+in+patients+with+type+2+diabetes.">Effect of weight loss by gastric bypass surgery versus hypocaloric diet on glucose and incretin levels in patients with type 2 diabetes.</a> J Clin Endocrinol Metab. 93 (7), 2479-2485 (2008).</li><li>Adams, T. D., 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=Health+benefits+of+gastric+bypass+surgery+after+6+years.">Health benefits of gastric bypass surgery after 6 years.</a> Jama. 308 (11), 1122-1131 (2012).</li><li>McGavigan, A. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=TGR5+contributes+to+glucoregulatory+improvements+after+vertical+sleeve+gastrectomy+in+mice.">TGR5 contributes to glucoregulatory improvements after vertical sleeve gastrectomy in mice.</a> Gut. , (2015).</li><li>Peterli, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvement+in+glucose+metabolism+after+bariatric+surgery:+comparison+of+laparoscopic+Roux-en-Y+gastric+bypass+and+laparoscopic+sleeve+gastrectomy:+a+prospective+randomized+trial.">Improvement in glucose metabolism after bariatric surgery: comparison of laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy: a prospective randomized trial.</a> Ann Surg. 250 (2), 234-241 (2009).</li><li>Ryan, K. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FXR+is+a+molecular+target+for+the+effects+of+vertical+sleeve+gastrectomy.">FXR is a molecular target for the effects of vertical sleeve gastrectomy.</a> Nature. 509 (7499), 183-188 (2014).</li><li>Wilson-Perez, H. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vertical+sleeve+gastrectomy+is+effective+in+two+genetic+mouse+models+of+glucagon-like+Peptide+1+receptor+deficiency.">Vertical sleeve gastrectomy is effective in two genetic mouse models of glucagon-like Peptide 1 receptor deficiency.</a> Diabetes. 62 (7), 2380-2385 (2013).</li><li>Pressler, J. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vertical+sleeve+gastrectomy+restores+glucose+homeostasis+in+apolipoprotein+A-IV+KO+mice.">Vertical sleeve gastrectomy restores glucose homeostasis in apolipoprotein A-IV KO mice.</a> Diabetes. 64 (2), 498-507 (2015).</li></ol>

The authors declare no conflicts of interest, except Dr. Cummings received funding from Eli Lilly and Company.

Bariatric surgery is the most effective long-term treatment for obesity and results in other health benefits such as high rates of type 2 diabetes and hypertension remission1,9,15. Murine models of bariatric surgery provide a powerful tool with which to identify the mechanisms by which bariatric surgery causes rapid and pronounced improvements in obesity comorbidities. Furthermore, murine models of bariatric surgery provide a no...

As the obesity epidemic continues to grow worldwide bariatric surgery has gained popularity as it is the most effective long-term treatment for obesity1. Unfortunately, weight loss by diet and exercise is difficult to achieve and relatively ineffective over the long-term2,3. Bariatric surgery, such as vertical sleeve gastrectomy (VSG), is defined as the manipulation of the gastrointestinal tract for the purpose of weight loss1,4. Although weight loss is a prominent outcome of bariatric surgery, bariatric surgery provides other health benefits such as improving obesity comorbidities and extending lifespan5. For example, bariatric surgery results in high rates of remission of type 2 diabetes and hypertension, and reductions in the lifetime risk of the development of certain types of cancer1,6,7. Of note, the effect of bariatric surgery causing remission of type 2 diabetes and hypertension is often observed soon after surgery and prior to weight loss8,9. This highlights the concept that there are mechanisms independent of body weight contributing to the health benefits observed after surgery. Animal models of bariatric surgery have been developed and are utilized to study the mechanisms by which these health benefits occur10,11,12.
We have validated a mouse model of VSG, which we have applied to various genetically modified mouse models to study the mechanisms by which bariatric surgery improves obesity comorbidities such as type 2 diabetes, hypertension, and colorectal cancer10,11,12. Rodent models allow more experimental control and the ability to perform genetic or pharmaceutical manipulation to define the role of specific genes or signaling pathways of interest. We are focusing primarily on VSG because VSG is the most commonly performed bariatric procedure in the clinic in the United States13. Additionally, VSG is a simple surgical model with fewer anatomic modifications compared to other procedures such as Roux-en-Y gastric bypass or biliopancreatic diversion.
Our mouse model of VSG recapitulates the following effects of bariatric surgery observed in humans: weight loss, reduced food intake, improved glucose regulation, improved islet function, increased post-prandial glucagon-like peptide-1 (GLP-1) secretion, reduced arterial blood pressure, and increased circulating bile acid concentrations10,11,12,13,14,15. Therefore, this is an ideal model to study the body weight dependent and independent mechanisms by which VSG improves or resolves obesity comorbidities. In addition, it is a reliable model that can be combined with other surgical procedures, allowing for the investigation of the impact of VSG under various disease conditions with greater mechanistic insight12.

<table>
	<tbody>
		<tr>
			<td>45% high fat diet</td>
			<td>Research Diets</td>
			<td>D12451</td>
			<td></td>
		</tr>
		<tr>
			<td>60% high fat diet</td>
			<td>Research Diets</td>
			<td>D12492</td>
			<td></td>
		</tr>
		<tr>
			<td>Boost</td>
			<td>Nestle</td>
			<td>160-67538</td>
			<td>rich chocolate flavor</td>
		</tr>
		<tr>
			<td>6-0 Suture</td>
			<td>Ethicon</td>
			<td>Z432</td>
			<td>monofilament absorbable/taper</td>
		</tr>
		<tr>
			<td>7-0 Suture</td>
			<td>Covidien</td>
			<td>8866127-01</td>
			<td>monofilament absorbable/taper</td>
		</tr>
		<tr>
			<td>Cotton Swabs</td>
			<td>Fisherbrand</td>
			<td>23-400-118</td>
			<td>small</td>
		</tr>
		<tr>
			<td>Cotton Swabs</td>
			<td>Fisherbrand</td>
			<td>233-400-101</td>
			<td>large</td>
		</tr>
		<tr>
			<td>Gauze</td>
			<td>Various</td>
			<td></td>
			<td>4x4 4 ply and 2x2 4 ply</td>
		</tr>
		<tr>
			<td>Foil</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Surgery drape</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>0.9% saline solution</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>LRS</td>
			<td>Hospira</td>
			<td>170RX</td>
			<td></td>
		</tr>
		<tr>
			<td>Betadine</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Alcohol</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Eye Ointment</td>
			<td>Paralube&#174; Vet Ointment</td>
			<td>17033-211-38</td>
			<td></td>
		</tr>
		<tr>
			<td>Tissue Adhesive</td>
			<td>Vetbond</td>
			<td>1469SB</td>
			<td></td>
		</tr>
		<tr>
			<td>Meloxicam (Metacam)</td>
			<td>Boehringer Ingelheim</td>
			<td>141-213</td>
			<td>5 mg/ml</td>
		</tr>
		<tr>
			<td>Enrofloxacin</td>
			<td>Baytril</td>
			<td>08713254-186599</td>
			<td>22.7 mg/ml</td>
		</tr>
		<tr>
			<td>Thin tipped hemostats</td>
			<td>Fine Science Tools</td>
			<td>13021-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Metzenbaum Scissor</td>
			<td>Fine Science Tools</td>
			<td>14018-18</td>
			<td></td>
		</tr>
		<tr>
			<td>Iris Scissors</td>
			<td>Fine Science Tools</td>
			<td>14058-09</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont Forcep</td>
			<td>Fine Science Tools</td>
			<td>11251-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Serrated Forcep</td>
			<td>Fine Science Tools</td>
			<td>11020-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Gavage needle</td>
			<td>Fine Science Tools</td>
			<td>18060-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Microneedle driver</td>
			<td>Fine Science Tools</td>
			<td>12075-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Spring Scissor</td>
			<td>Fine Science Tools</td>
			<td>15396-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulin syringe</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1mL syringe</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>20mL syringe</td>
			<td>Various</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glucometer (one touch ultra mini)</td>
			<td>Lifescan</td>
			<td>70021208</td>
			<td></td>
		</tr>
		<tr>
			<td>Multiplex insulin and GLP-1 kit</td>
			<td>Meso Scale Discovery</td>
			<td>K15171C-1</td>
			<td></td>
		</tr>
		<tr>
			<td>GraphPad Prism 6.00</td>
			<td>GraphPad Software</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nestlets</td>
			<td>Ancare</td>
			<td>NES3600</td>
			<td></td>
		</tr>
	</tbody>
</table>

a murine model of vertical sleeve gastrectomy

Bariatric surgery, such as vertical sleeve gastrectomy (VSG), is a surgery of the gastrointestinal tract that is performed for the purpose of weight loss. Bariatric surgery is currently the most effective long-term treatment for obesity. In addition to weight loss, bariatric surgery produces additional health benefits such as remission of type 2 diabetes, remission of hypertension, and decreased risk of developing certain types of cancer. The mechanisms beyond weight loss for these benefits remain incompletely defined. Therefore, animal models of bariatric surgery are being developed and validated to identify the mechanisms leading to these benefits, with the goal of improving understanding of gastrointestinal physiology and identifying new therapeutic targets. VSG has become the most commonly performed bariatric procedure in the clinic in the United States because it is highly effective at producing weight loss and metabolic improvement, and is simpler to perform than other bariatric procedures. Therefore, we have developed and validated a murine model of VSG. This murine VSG model recapitulates many of the effects of VSG seen in humans, including improved glucose and blood pressure regulation. The method is based on isolation of the stomach, ligation of gastric vessels, and removal of 70% of the stomach by transecting along the greater curvature of the stomach. We have successfully applied this surgical protocol to various genetically modified mouse lines to define the mechanistic contributors to the benefits of VSG. Furthermore, this murine VSG model has been combined with other surgical techniques, to achieve deeper mechanistic insight. Therefore, this is a simple and versatile model for studying gastrointestinal physiology and the health benefits of bariatric surgery.

The sham and VSG procedures are depicted in Figure 1. Figure 1A shows where the suture line is placed along the gastric walls during the sham procedure. This same area is where the stomach is cut during VSG surgery. Figure 1B shows the tubular remnant of stomach left after performance of VSG.
Statistics and Data Analysis<br...

Watch this Scientific Journal Video about A Murine Model of Vertical Sleeve Gastrectomy at JoVE.com

A Murine Model of Vertical Sleeve Gastrectomy

The following describes the performance of vertical sleeve gastrectomy in mice. This is a type of weight-loss surgery that involves removal of approximately 70% of the stomach.

Bariatric surgery, such as vertical sleeve gastrectomy (VSG), is a surgery of the gastrointestinal tract that is performed for the purpose of weight loss. ...

The overall goal of this procedure is to model the health benefits of vertical sleeve gastrectomy in mice. This method can help answer key questions in obesity research about the mechanisms by which bariatric surgery improves obesity and obesity comorbidities. The advantage of this technique is that it provides a model for studying these mechanisms which will facilitate identification of novel targets for the treatment of obesity and its comorbidities.Before beginning the procedure, apply veterinary ointment to the eyes of an anesthetized mouse and place the mouse on a heating pad. Remove the hair from the umbilicus to the axilla gently holding the skin taught to avoid skin lesions and use cotton-tip applicators to sequentially disinfect the exposed skin with povidone-iodine and ethanol. Wearing sterile gloves and using sterile technique, place sterile surgical drapes on either side of the animal.Cut a small hole in the foil to allow access to the mouse's abdomen and use a piece of autoclaved aluminum foil as a surgical drape. Make a skin incision from the mid abdomen to the xiphoid cartilage. Under a dissecting microscope, use iris scissors to cut through the body wall along the linea alba.And use new cotton-tip applicators to gently elevate the stomach out of the abdomen. Bluntly dissect the greater omentum from the greater curvature of the stomach. Then use 7-0 monofilament absorbable sutures to place two ligatures around the short gastric artery that runs between the fundus of the stomach and the spleen.When both ligatures have been placed, use spring scissors to cut between the two sutures and fully exteriorize the stomach from the abdominal cavity. Place gauze under the stomach and hydrate the organ with saline. For a sham procedure, use a 6-0 monofilament absorbable suture with a taper needle to place a loose simple continuous pattern starting two millimeters to the right of the esophagus along the ventral gastric wall and continuing along the dorsal gastric wall.Make sure the suture lies flat without restricting the stomach and use three to four throws to gently tie off the suture. For a vertical sleeve gastrectomy procedure, use a 7-0 monofilament absorbable suture with a taper needle to ligate the prominent branches of the gastric artery and vein just below the intended line of transection. Place a simple continuous line of 6-0 monofilament absorbable suture through both gastric walls just below the intended line of transection to prevent spillage of the gastric contents.Place thin-tipped hemostats above the suture line and use spring scissors to cut between the suture line and the hemostats. Remove the transected gastric tissue from the sterile surgical field and use fresh cotton-tip applicators to clean the blood and digesta from the stomach. Use a 6-0 monofilament absorbable suture with a taper needle to reinforce the apposition of the gastric walls in a simple discontinuous pattern.Using a 20-gauge gavage needle attached to a 20-milliliter syringe, perform gastric lavage with fresh saline and securely close the stomach with a minimum of 20 knots. Then gently press the stomach with a cotton applicator to test for leaks. If no leaks are detected, lavage the stomach with at least 60 more milliliters of fresh saline to remove any infectious particulates.After either procedure, use a cotton-tip applicator to return the stomach under the liver within the abdominal cavity and place an applicator along the dorsal aspect of the abdominal cavity to absorb any excess fluid. Use a blunt 18-gauge needle to inject lactated Ringer's solution with our without antibiotics directly into the abdominal cavity and use 6-0 monofilament absorbable sutures to close the abdominal muscle layer in a simple discontinuous pattern and the skin layer in a simple continuous pattern. Then place tissue adhesive on the skin and fold the skin over the suture line to protect the suture from disruption by the animal.Vertical sleeve gastrectomy operated, high-fat-diet fed mice exhibit a reduced energy intake and body weight compared to ad libitum fed, sham operated mice. Vertical sleeve gastrectomy improves glucose tolerance, increases glucose stimulated insulin secretion and increases postprandial glucagon-like peptide one secretion compared to sham operated, ad libitum fed control mice consistent with outcomes observed in humans and other rodent models of bariatric surgery. Once mastered, this procedure should be performed in 90 minutes.While learning this procedure it is important to remember to be gentle when manipulating the gastrointestinal tract. The GI tract is a very sensitive organ in mice and accidental manipulation of the small intestine can lead to GI stasis. After successfully learning this procedure, researchers can apply genetic or pharmaceutical manipulations to various disease models to investigate the mechanisms by which bariatric surgery improves health.

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10.9K Görüntüleme.  Cornell University. The overall goal of this procedure is to model the health benefits of vertical sleeve gastrectomy in mice. This method can help answer key questions in obesity research about the mechanisms by which bariatric surgery improves obesity and obesity comorbidities. The advantage of this technique is that it provides a model for studying these mechanisms which will facilitate identification of novel targets for the treatment of obesity and its comorbidities.Before beginning the procedure, ap...