Nowadays, bariatric surgery is the only effective treatment for morbid obesity as it induces significant weight loss that is maintained over the long term. However, the adverse effects of gastrointestinal remodeling induced by long-term surgery have not yet been fully characterized.

The last study published by the PIMS team (M. Le Gall & A Bado) in Scientific Reports compared, in a preclinical rat model, the long-term consequences of two types of bariatric surgery: one anastomosis gastric bypass (OAGB) and Roux-en-Y gastric bypass (RYGB) (see Figure). The authors evaluated the influence of biliopancreatic limb length, malabsorption and bile acid reflux on the esogastric mucosa.

After 30 weeks of follow-up, rats operated on OAGB presented a higher rate of esophagitis, fundal gastritis and peri-anastomotic foveolar hyperplasia compared to rats operated on RYGB. In addition, rats operated on OAGB with a long biliopancreatic limb also had greater weight loss and malabsorption. On the contrary, bile acid concentrations were highest in the residual gastric pouch of rats operated on OAGB with a shorter biliopancreatic limb. However, no association could be established between esogastric lesions, malabsorption, weight loss or bile acid concentrations in the residual gastric pouch. Finally, no cases of esophageal cancer, metaplasia, dysplasia, or Barrett’s esophagus have been reported.

In conclusion, in this preclinical rat model, RYGB bariatric surgery gives a better long-term outcomes than OAGB, as chronic signs of biliary reflux or reactive gastritis were observed after OAGB, even after reduction in the length of the biliopancreatic limb.

This study encourages the follow-up of patients operated on OAGB to ensure that they do not develop esogastric lesions in the long-term.

Figure: Remodeling of the gastrointestinal tract after 2 bariatric surgeries:  Roux-en-Y Gastric Bypass (RYGB) and Gastric Bypass to Anastomosis (OAGB).