A Rodent Model of Adjustable Gastric Band Surgery—Implications for the Understanding of Underlying Mechanisms

Obesity Surgery (Impact Factor: 3.74). 05/2009; 19(5):625-631. DOI: 10.1007/s11695-008-9751-0

ABSTRACT BackgroundBariatric surgery is currently the only anti-obesity therapy that can deliver weight loss of up to 20–30% of body weight.
Laparoscopic adjustable gastric banding (LAGB) and Roux-en-y gastric bypass are the most commonly performed of these surgeries.
The mechanisms by which LAGB initiates an increase in satiety remain completely unknown. The aim of this study is to establish
a rodent model of adjustable gastric banding (AGB) that will enable investigation of these mechanisms.

MethodsSprague–Dawley rats were implanted with adjustable gastric bands immediately below the gastro-esophageal junction around the
glandular stomach. This band, as in humans, can be inflated via an exteriorized port resulting in an incremental impact on
the stomach.

ResultsRats with an incremental inflation of the AGB showed a clear stepwise reduction in food intake and body weight. Normal food
intake and body weight gain were restored with band deflation. Barium-assisted X-ray of the stomach showed the formation of
a small gastric pouch proximal to the inflated band in a manner analogous to the human LAGB.

ConclusionsThis is the first animal model of the AGB that allows incremental inflation for optimal tightening of the band in the conscious
animal with corresponding effects on food intake and body weight. This model will allow measurement of acute and chronic neural
and hormonal changes following activation of the band in the conscious animal and will provide the potential to inform and
improve surgical approaches that are at the forefront of obesity treatments.

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    ABSTRACT: Bariatric procedures vary in efficacy, but overall are more effective than behavioral and pharmaceutical treatment. Roux-en-Y Gastric Bypass causes increased secretion of Glucagon-like peptide 1 (GLP-1), and reduces body weight more than adjustable gastric banding (AGB), which does not trigger increased GLP-1 secretion. Since GLP-1-based drugs consistently reduce body weight, we hypothesized that GLP-1 receptor (GLP-1R) agonists would augment the effects of AGB. Male Long Evans rats with diet-induced obesity received AGB implantation or sham surgery. GLP-1R agonism, cannabinoid receptor-1 (CB1-R) antagonism, or vehicle was combined with inflation to evaluate interaction between AGB and pharmacological treatments. GLP1-R agonism reduced BW in both sham and AGB rats (left un-inflated) compared to vehicle-treated animals. Subsequent band inflation was ineffective in vehicle-treated rats, but enhanced weight loss stimulated by GLP1-R agonism. In contrast, there were no additional BW loss when CB1-R antagonism was given with AGB. We found band inflation to trigger neural activation in areas of the nucleus of the solitary tract known to be targeted by GLP1-R agonism, offering potential mechanism for the interaction. These data show that GLP-1R agonism, but not CB1-R antagonism, improves weight loss achieved by AGB, and suggest an opportunity to optimize bariatric surgery with adjunctive pharmacotherapy.
    Diabetes 06/2013; 62(9). DOI:10.2337/db13-0117 · 8.47 Impact Factor
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    ABSTRACT: OBJECTIVE:: To examine the influence of age and gender on the development of proximal gastric pouch distension (PPD) after laparoscopic adjustable gastric banding (LAGB) surgery. BACKGROUND:: PPD is the most common reason for revision with adjustable gastric banding surgery. Maintaining the anatomical integrity of bariatric surgery is a key to long-term success. It is therefore important to understand risk factors for complications. METHODS:: We extracted details of 3000 consecutive individuals who underwent primary LAGB procedures at a single center between February 2005 and May 2011. Contemporaneous details of all complications were recorded in a database. The characteristics of those that subsequently required revision surgery for PPD were assessed and compared with those that did not. RESULTS:: There were 132 cases for PPD requiring surgical intervention before September 2011. Incident PPD occurred in 5.1% and 1.3% of women and men, respectively. The mean age of those with PPD was 39.9 ± 9.25 compared with 43.9 ± 11.0 for those without it. The age and gender effects were independent, and the age effect was restricted to women. The adjusted odds ratios were 0.971 (95% CI [confidence interval], 0.954-0.986, P < 0.001) for age and 0.26 (95% CI, 0.12-0.56, P = 0.001) for male gender and younger women were more likely to have asymmetrical distension. CONCLUSIONS:: Younger women are at higher risk of PPD after LAGB surgery than men and women older than 50 years. Sex hormones may play a role in predisposing to gastric stretch after surgery. These findings may apply more broadly to the gastric "restrictive" component of other bariatric procedures.
    Annals of surgery 04/2012; 257(3). DOI:10.1097/SLA.0b013e3182504665 · 7.19 Impact Factor
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    ABSTRACT: BACKGROUND:Bariatric surgical procedures, including the laparoscopic adjustable gastric band (LAGB), are currently the only effective treatments for morbid obesity, however, there is no clear understanding of the mechanisms underpinning the efficacy of LAGB. The aim of this study is to examine changes in activation of the sensory neuronal pathways and levels of circulating gut hormones associated with inflation of an AGB.DESIGN AND RESULTS:The trajectory within the central nervous system of polysynaptic projections of sensory neurons innervating the stomach was determined using the transsynaptically transported herpes simplex virus (HSV). Populations of HSV-infected neurons were present in the brainstem, hypothalamus and cortical regions associated with energy balance. An elevation of Fos protein was present within the nucleus of the solitary tract, a region of the brainstem involved in the control of food intake, following acute and chronic band inflation. Two approaches were used to test (1) the impact of inflation of the band alone (on a standard caloric background) or (2) the impact of a standard caloric meal (on the background of the inflated band) on circulating gut hormones. Importantly, there was a significant elevation of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) following oral gavage of a liquid meal in animals with pre-inflated bands. There was no impact of inflation of the band alone on circulating GLP-1, PYY or ghrelin in animals on a standard caloric background.CONCLUSION:These data are consistent with the notion that the LAGB exerts its effects on satiety, reduced food intake and reduced body weight by the modulation of both neural and hormonal responses with the latter involving an elevation of meal-related levels of GLP-1 and PYY. These data are contrary to the view that the surgery is purely 'restrictive'.International Journal of Obesity advance online publication, 27 March 2012; doi:10.1038/ijo.2012.25.
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