Insights into underlying mechanism and improved efficacy of the adjustable gastric band (#129)
Currently, bariatric surgery remains the only effective treatment for morbid obesity. Laparoscopic adjustable gastric banding (LAGB) is one of the most commonly performed bariatric procedures; however, the mechanism(s) underlying its efficacy are unclear. This study aims to elucidate the role of sensory neural pathways in mediating AGB-induced satiety in a rodent model and assess the effectiveness of adjuvant therapies on AGB-induced weight loss.
Adult male Sprague Dawley rats (n=8-10/group) were fitted with an AGB, just below the gastro-oesophageal junction. To determine the importance of vagal sensory afferents in mediating the increase in neural activation following gastric band inflation, capsaicin was used to ablate unmyelinated c-fibres. Biotelemetry devices implanted between the interscapular lobes of brown adipose tissue (BAT) were used to assess the impact of AGB on energy expenditure in BAT. Pharmacological agents (thyroxine and Contrave) were combined with AGB inflation for four weeks to assess their impact on AGB induced weight loss.
Capsaicin treatment resulted in a complete elimination of the elevated Fos labelling in the NTS but only a partial attenuation of AGB induced weight loss. Furthermore, AGB induced reductions in body weight and fat mass in obese rats are associated with reductions in energy expenditure that can be effectively ameliorated by co-treatment with factors such as thyroid hormone, which increase energy expenditure in BAT (p<.05).
These data support the hypothesis that LAGB exerts its effects via the modulation of both, neural and hormonal pathways. Adjuvant therapies that increase energy expenditure can enhance the effectiveness of the AGB.