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World J Diabetes. Jan 25, 2016; 7(2): 27-33
Published online Jan 25, 2016. doi: 10.4239/wjd.v7.i2.27
From bariatric to metabolic surgery: Looking for a “disease modifier” surgery for type 2 diabetes
Renzo Cordera, Gian Franco Adami
Renzo Cordera, Department of Internal Medicine, University of Genova, 16132 Genova, Italy
Gian Franco Adami, Department of Surgery, University of Genova, 16132 Genova, Italy
Author contributions: Authors equally contributed to this review article from its conception to critically analyzing literature, drafting and editing the manuscript.
Conflict-of-interest statement: Authors declare no conflicts of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Renzo Cordera, MD, Professor of Endocrinology, Department of Internal Medicine, University of Genova, Viale Benedetto XV, 6, 16132 Genova, Italy. record@unige.it
Telephone: +39-10-3538947
Received: July 24, 2015
Peer-review started: July 30, 2015
First decision: October 30, 2015
Revised: December 8, 2015
Accepted: December 29, 2015
Article in press: January 4, 2016
Published online: January 25, 2016
Processing time: 175 Days and 9.3 Hours
Abstract

In this review the recent evolution of the comprehension of clinical and metabolic consequences of bariatric surgery is depicted. At the beginning bariatric surgery aim was a significant and durable weight loss. Later on, it became evident that bariatric surgery was associated with metabolic changes, activated by unknown pathways, partially or totally independent of weight loss. Paradigm of this “metabolic” surgery is its effects on type 2 diabetes mellitus (T2DM). In morbid obese subjects it was observed a dramatic metabolic response leading to decrease blood glucose, till diabetes remission, before the achievement of clinically significant weight loss, opening the avenue to search for putative anti-diabetic “intestinal” factors. Both proximal duodenal (still unknown) and distal (GLP1) signals have been suggested as hormonal effectors of surgery on blood glucose decrease. Despite these findings T2DM remission was never considered a primary indication for bariatric surgery but only a secondary one. Recently T2DM remission in obese subjects with body mass index (BMI) greater than 35 has become a primary aim for surgery. This change supports the idea that “metabolic surgery” definition could more appropriate than bariatric, allowing to explore the possibility that metabolic surgery could represent a “disease modifier” for T2DM. Therefore, several patients have undergone surgery with a primary aim of a definitive cure of T2DM and today this surgery can be proposed as an alternative therapy. How much surgery can be considered truly metabolic is still unknown. To be truly “metabolic” it should be demonstrated that surgery could cause T2DM remission not only in subjects with BMI > 35 but also with BMI < 35 or even < 30. Available evidence on this topic is discussed in this mini-review.

Keywords: Obesity; Severe obesity; Obesity related metabolic co-morbidities; Type 2 diabetes; Type 2 diabetes remission; Type 2 diabetes control; Bariatric/metabolic surgery

Core tip: In severely obese patients with type 2 diabetes mellitus (T2DM), weight loss after bariatric surgery is often accompanied by long term remission of T2DM and other obesity co-morbidities, these anti-diabetic outcomes are due both to body fat loss and to still unknown factors specifically regulated by surgery. On the other hand, the same surgical procedures in obese patients with a body mass index < 35, are associated with T2DM remission in only 50% of subjects. These findings raise the question whether bariatric surgery could be considered a metabolic one. We propose that “bariatric” surgery could be considered “metabolic” only in the case that it could demonstrate its effect on long lasting T2DM remission in morbid as well as in non-morbid obese subjects.