A Prospective Randomized Controlled Study Of Gastric Bypass Surgery For Nonobese Type 2 Diabetes Mellitus

Background Bariatric operations such as Roux-en-Y gastric bypass (RYGB) and Biliopancreatic diversion (BPD) caused impressive improvement of type 2 diabetes millitus (T2DM) was found in the severely obese patients who underwent gastric bypass(GBP) to facilitate weight loss. Large majority of the patients experienced durable remission of T2DM. Recently, the trials of RYGB in people with body mass index (BMI) lower than 35 kg/m2 have reported similar or even higher diabetes remission rates than those conducted in severely obese patients. Consistent with theses reports, experimental studies indicate that RYGB improve T2DM in both obese and nonobese diabetic animals. The mechanisms mediating antidiabetic effects of bariatric procedure remain poorly understood. The glycemic control improves more after RYGB than after purely restrictive bariatric operations, indicating that antidiabetic effect of RYGB is likely related to intestinal bypass and further research is needed..Objective The aim of this study was to compare the therapeutic effects of 4 commonly used gastrointestinal reconstruction operations on nonobese T2DM, and then, to investigate that exclusion of a short segment of proximal small intestine (primarily the duodenum) from contact with ingested nutrients exerts antidiabetes effects, presumably via different gastric bypass operations and the key position that influence antidiabetic effects. The results from this study might to guide selection the way of digestive tract reconstruction for nonobese patients with T2DM, and to elucidate the antidiabetes mechanisms of gastric bypass.Methods This study was a prospective randomized controlled clinical study involving 40 nonobese T2DM patients(BMI<35 kg/m2) who associated with gastritic diseases had to gastrectomy and digestive tract reconstruction.40 patients were randomized divided into four groups exception of who could not tolerate the operation.4 operations include total gastrectomy Y-anastomosis (RY), subtotal gastrectomy BillrothⅡgastro-jejunostomy completion(BⅡ) and BⅠ-type distal gastrectomy with gastroduodenal anastomosis (BⅠ), and proximal gastrectomy remnant gastric esophageal anastomosis (PG). The follow-up period was for 6 month after operayion. The clinical outcomes were compared between 4 groups. Clinical observations and laboratory examinations include BMI, waist circumference, taking hypoglycemic drug dosage, fasting blood glucose, glycated hemoglobin(GHbAl), plasma insulin and C-peptide levels at baseline and postoperation. ResultsThe clinical effects of the four different operative procedures on the primary diseases were similar, and there was no significant differences in the patient's hospitalization days, surgery healing, body weight and waist circumference and the disease recovery state (P> 0.05).In B I group,3 patients reduced the oral blood glucose dosage and 7 patients had no changes. In PG group,2 patients reduced the insulin dosage of controlling of blood glucose and 8 patients had no changes. In RY group,2 patients'blood glucose and GHbAl levels were normal and stopped the dosage; 7 patients reduced the insulin dosage of controlling of blood glucose and 1 patient had no changes. In BⅡgroup,2 patients'blood glucose and GHbAl levels was normal and stoping the dosage; 2 patients reduced the insulin dosage of controlling of blood glucose; 5 patients reduced the oral blood glucose dosage and 1 patient had no changes.The BⅡgroup and the RY group at fasting blood glucose decreased significantly; while the BⅠgroup and the PG group had no significant improvement of postoperative changes in blood glucose (P> 0.05). Comparing with these groups showed that the group BⅡand the RY group's blood glucose decrease was significantly stronger than the BⅠgroup and the PG group (P<0.05);and there was no significant difference of blood glucose among others (P> 0.05).The GHbAl of BⅡgroup surgery after 1 month and RY group surgery after 2 months decreased significantly (P<0.05); but BⅠgroup and PG group had no significant postoperative change (P>0.05). After the surgery, BⅡgroup (2 months:P<0.05; 6 months: P<0.01))and RY groups (6 months:P<0.01) GHbAl decrease situation had the significantly difference comparing with BⅠgroup and PG groups; and there was no big difference for others (P>0.05)The plasma insulin levels were significantly increased for BⅡgroup and RY groups after the surgery for 1 month (P<0.05); and the insulin level had no significant difference before and after the surgery for BⅠand PG group (P>0.05). The plasma insulin levels increasing between BⅡand RY groups had the significant difference comparing with BⅠgroup and PG groups (P＜0.05); and the others had no significant difference (P>0.05) The C-peptide levels for BⅡand RY groups were progressively increased, and it increased to the most obvious state for 6 months(P<0.01). The C-peptide levels were no significant difference for BⅠand PG groups before and after the surgery(P>0.05); the C-peptide levels increasing were significant difference between BⅡand RY groups comparing with BⅠand PG groups after the surgery(P<0.05); and the others had no significant difference (P>0.05).Conclusion The surgery results for primary diseases of 4 operations were very similar. The gastro-intestinal surgery caused impressive improvement of T2DM in patients with RY and BⅡmore effectively than with BⅠand PG. The results indicate that GBP has significantly antidiabetic effect for nonobese patients with T2DM. The gastrectomy in 4 operations was unlikely related to the antidiabetic effect, as neither total gastrectomy nor varied subtotal gastrectomy could influence the effect. Glycemic control improves more after RY and BⅡthan after BⅠand PG indicating that effect is likely related to intestinal bypass and that exclusion proximal small intestine (primarily the duodenum) from contact with ingested nutrients is the key procedure for antidiabetic effects. Although there were some difference in 2 GBP procedures(BⅡand RY), the antidiabetic effects were very similar. This result suggest that gastric bypass did in our study differences in ways and length did not influence the antidiabetic effect.In summary, the results in our study proved GBP antidiabetic effect mediated by enhancing insulin secretion, increasing C peptide level,and decrease in glycated hemoglobin, which consistent with the reports of gut-islet-axis theory. In Surgical treatment for patients with gastrointestinal diseases associated with T2DM the gastric bypass similar to RYGB is an important priority according to such insights, so that patients can get the best therapeutic effect.