Gastric Bypass Is not a "Restrictive and Malabsorptive" Procedure

From the Knife to the Endoscope-a History of Bariatric Surgery

PURPOSE OF REVIEW

This review was conducted to gain insight into the history, present and future of bariatric and/or metabolic surgery and endoscopic treatments of obesity. The challenges that have been overcome, the challenges we still face and our recommendations for the future are discussed.

RECENT FINDINGS

Over the last few decades, a number of treatment strategies have emerged for the treatment of obesity. Both endoscopic and surgical options are available and they lead to significant weight loss and comorbidity reduction. However, to remain a credible treatment alternative to the obesity pandemic, we need to perform these procedures in much larger numbers than we currently do. Even though significant gains have been made in reducing the morbidity and mortality of surgical interventions, there is further room for improvement, especially when it comes to long-term issues. Due to its impact on almost every single organ system in the human body, bariatric surgery has attracted the attention of academics from a variety of medical disciplines. This has led to a rapidly enlarging body of high-quality scientific literature, supporting its wider use and cost-effectiveness.

CONCLUSION

Despite the advances made in bariatric surgery, the criteria determining suitability of patients for bariatric surgery in most parts of the world are still based on a consensus agreed upon in the USA in 1991. There is a need to formulate some new consensus and guidelines that would allow for a significant expansion of the pool of patients that can be offered these procedures.

Bile acids and bariatric surgery

Bariatric surgery, specifically Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG), are the most effective and durable treatments for morbid obesity and potentially a viable treatment for type 2 diabetes (T2D). The resolution rate of T2D following these procedures is between 40 and 80% and far surpasses that achieved by medical management alone. The molecular basis for this improvement is not entirely understood, but has been attributed in part to the altered enterohepatic circulation of bile acids. In this review we highlight how bile acids potentially contribute to improved lipid and glucose homeostasis, insulin sensitivity and energy expenditure after these procedures. The impact of altered bile acid levels in enterohepatic circulation is also associated with changes in gut microflora, which may further contribute to some of these beneficial effects. We highlight the beneficial effects of experimental surgical procedures in rodents that alter bile secretory flow without gastric restriction or altering nutrient flow. This information suggests a role for bile acids beyond dietary fat emulsification in altering whole body glucose and lipid metabolism strongly, and also suggests emerging roles for the activation of the bile acid receptors farnesoid x receptor (FXR) and G-protein coupled bile acid receptor (TGR5) in these improvements. The limitations of rodent studies and the current state of our understanding is reviewed and the potential effects of bile acids mediating the short- and long-term metabolic improvements after bariatric surgery is critically examined.