The Effects of the Laparoscopic Roux-en-Y Gastric Bypass and the Laparoscopic Mini Gastric Bypass on the Remission of Type II Diabetes Mellitus and the Pathophysiological Mechanisms That Drive the Conversion of Malign to Benign Obesity

Metabolic surgery has proven to be a viable long-term solution in the treatment of morbid obesity and its comorbidities. It induces rapid remission of type 2 diabetes mellitus (T2DM). Type 2 Diabetes Mellitus is present in one quarter of patients at the bariatric outpatient clinic. Non alcoholic fatty liver disease (NAFLD) is present in 80% of all morbidly obese subjects and is a major risk factor for development of insulin resistance and non alcoholic steatohepatis (NASH), with the latter becoming the major indication for liver transplantation in the USA. It is increasingly recognized that the immune system, possibly driven by innate lymphoid cells (ILC's), and the intestinal microbiome are major players in this obesity related disease and the switch from benign to malign (insulin resistance and T2DM) obesity. However, the exact mechanisms of action behind the surgery-driven switch back from malign to benign obesity are unknown. Also, it is undecided which metabolic surgery grants best results in the remission of T2DM and which procedure does that at the lowest rate of surgical complications, long term difficulties and side effects. The Laparoscopic Roux-en-Y Gastric Bypass (LRYGB), an efficient but complex procedure, is the golden standard in the Netherlands. The Laparoscopic Mini Gastric Bypass (LMGB) is technically less challenging and has been introduced to overcome some of the limitations of LRYGB. It has been hypothesized that the LMGB has a more rapid and durable glycaemic control, possibly due to the altered constitution and the augmented length of the biliary limb. There is reason to believe that the improved glycaemic control might become apparent within the first year of surgery and that it might remain thereafter. However, it is unknown what order of magnitude is to be expected and whether subgroups of T2DM patients will benefit the LMGB more. Also, it is unknown whether and to what extent intestinal microbiota and immunological tone can predict the metabolic response (improvement in insulin sensitivity) and NAFLD/NASH reduction and whether differences are expected between these two surgeries. Increased understanding of the pathophysiological mechanisms as well as their relationship to metabolic disturbances are thought to be of crucial importance to discover new diagnostic and therapeutical targets in obesity associated insulin resistance/T2DM and NAFLD/NASH. Primary objective is to evaluate and compare the glycaemic control in T2DM within the first year of LRYGB and LMBG. Secondary aim is to gain insight in the pathophysiological mechanisms that drive the conversion of malign to benign obesity.