Functional Restriction and a New Balance between Proximal and Distal Gut: The Tools of the Real Metabolic Surgery

This article aims to question the utility of current surgical methods and their alternatives for the treatment of worldthreatening “diabesity” pandemic. We, as surgeons, need to address the following question honestly—“Are we offering the best surgical procedure to our patients?” Despite the evidence suggestive of inadequate and disappointing results with restrictive techniques like vertical banded gastroplasty (VBG) and gastric banding, why is the surgical fraternity still performing restrictive operations and trying to revise the restrictive or combination operations (i.e., gastric bypass) with further restriction? It is quite unfortunate to note the growing number of revision operations performed by bariatric and metabolic surgeons. Apparently, any restriction on humans seems to fail eventually, as observed with mechanical restrictive operations done for the surgical treatment of obesity. Therefore, we wish to highlight the potential surgical use of ileal anorexigenic neuropeptides (i.e., GLP-1, PYY, and oxyntomodulin) for the treatment of metabolic syndrome and related co-morbidities. From this perspective, it is plausible to take a short look at the physiology of hunger and satiety. After ingesting a portion of a meal, the food is sent to the gut for digestion. Hunger is a vital primitive instinct, which is not resolved in the stomach, but in the gut. Only when food reaches the ileum does signals of satiety are released, gastric emptying slows down, and a feeling of fullness coincides. Thus, satisfaction occurs only after eating a considerable amount of food and not after the first bite. However, restrictions like a band, pouch, narrow anastomosis, or a tube, limit ingestion and are unable to provide a marked intestinal satiety as a natural consequence of the abovementioned physiological process. Mechanical restriction represents a static obstacle for the passage of food after each ingestion step, and is clearly counterintuitive from a physiological viewpoint [1]. On the other hand, ileal proximalization and activation of the ileal peptides may bring forth a type of “functional restriction” and “metabolic satiety” that limit the stocking, not ingestion. Metabolic surgery should stay away from mechanical restriction and target a functional restriction. The only possible way to accomplish this is to activate the ileal anorexigenic neuropeptides in the early course of digestion. If the intestinal satiety signals are too weak or come late during digestion, it would be possible for an individual to consume greater amounts of food before the emergence of metabolic satiety. Malabsorptive operations, particularly biliopancreatic diversion (BPD) and duodenal switch (DS), do have the capability to induce the release of these peptides, since the whole jejunum is bypassed, and the gastro–ileal or duodeno–ileal anastomosis deliver food directly into ileum. However, these operations have a price to pay in the form of malabsorption and nutritional deficiencies. On the other hand, “functional restriction” through surgical ileal proximalization offers a chance to release the aforementioned peptides without causing significant malabsorption. These peptides not only induce satiety, but also improve the insulinemic responses, suppress the activity and release of glucagon, and decrease endogenous glucose production and free fatty acid release. Two major issues should be addressed though. Firstly, how can it be possible to obtain surgical ileal proximalization without causing significant malabsorption, and secondly, what is the significance of the presence of malabsorption after A. Celik (*) Department of Metabolic Surgery, Taksim German Hospital, Siraselviler Cad. No. 119Beyoglu Istanbul, Turkey e-mail: [email protected]