Preserving Duodenal-Jejunal (Foregut) Transit Does Not Impair Glucose Tolerance and Diabetes Remission Following Gastric Bypass in Type 2 Diabetes Sprague-Dawley Rat Model

Enteroendocrine Reprogramming by Altered Epithelial-Mesenchymal Crosstalk in Metabolic Surgery

Metabolic surgery is an effective treatment option for type 2 diabetes. However, the therapeutic scope has been limited by unexpected inconsistent outcomes. This study aims to overcome these obstacles by determining fundamental mechanisms from a novel perspective by analyzing and comparing the surgical anatomy, clinical characteristics, and outcomes of metabolic surgery, including duodenal-jejunal bypass, Roux-en-Y gastric bypass, biliopancreatic diversion, one anastomosis gastric bypass, and their modified procedures, predominantly focusing on nonobese patients to mitigate confounding effects from overweighted type 2 diabetes. Regional epithelial cell growth and unique villus formation along the anterior-posterior axis of the small intestine depend on crosstalk between the epithelium and the underlying mesenchyme. Due to altered crosstalk between the epithelium and the opposite mesenchyme at the anastomotic site, the enteroendocrine lineage of the distal intestine is replaced by the proximal epithelium after the bypass procedure. Subsequent intestinal compensatory proliferation accelerates the expansion of the replaced epithelium, including enteroendocrine cells. The primary reasons for unsatisfactory results are incomplete duodenal exclusion and insufficient biliopancreatic limb length. We anticipate that this novel mechanism will have a significant impact on metabolic surgery outcomes and provide valuable insight into optimizing its effectiveness in type 2 diabetes.

Comparison of three different anastomotic methods of sleeve gastrectomy with transit bipartition using an obese rodent model

The long-term effects and safety of single-anastomosis sleeve ileal (SASI) bypass have not been confirmed. The one anastomosis procedure carries the risk of bile reflux, and Braun anastomosis has the capacity to reduce bile reflux. This study was designed to compare the influences of bile reflux and histological changes in the esogastric sections of rats. Obese Sprague-Dawley rats underwent sleeve gastrectomy with transit bipartition (RYTB) (n = 12), SASI (n = 12), SASI bypass with Braun anastomosis (BTB) (n = 12), esojejunostomy (EJ) (n = 12), and SHAM (n = 8) surgery. During the 12-week follow-up period, weight changes, glucose improvement, and changes in serum nutrition were evaluated. Histological expression and bile acid concentration in the rats in all groups were also evaluated. No significant differences in weight loss and glucose improvements were observed in the RYTB, SASI, and BTB groups. The RYTB and BTB groups had significantly lower bile acid concentration and albumin levels than the SASI group. In addition, mucosal height in the RYTB and BTB groups was significantly lower than in the SASI group. Braun anastomosis had a significant effect on anti-reflux. BTB may be a superior primary procedure due to its potential for parallel bariatric and metabolic improvements, effective anti-reflux effects, simplified operations, and avoidance of severe malnutrition. Further clinical studies are needed to confirm these findings.

Effect of duodenal-jejunal bypass on diabetes in the early postoperative period

Metabolic surgery is an effective treatment for patients with type 2 diabetes mellitus (T2DM). The aim of this study was to investigate the effect of duodenal-jejunal bypass (DJB) in a rat model of T2DM during the early postoperative period. A rat model of non-obese T2DM was allocated to two groups: a sham group and a DJB group. On postoperative day 1 (1POD), oral glucose tolerance testing (OGTT) was performed and the changes of glucose transporter expressions in the small intestine was evaluated. [18F]-fluorodeoxyglucose ([18]-FDG) uptake was measured in sham- and DJB-operated rats using positron emission tomography-computed tomography (PET-CT). DJB improved the glucose tolerance of the rats on 1POD. The expression of sodium-glucose cotransporter 1 (SGLT1) and glucose transporter 1 (GLUT1) was high, and that of GLUT2 was low in the alimentary limb (AL) of rats in the DJB group. PET-CT showed that [18F]-FDG uptake was high in the proximal jejunum of DJB-operated rats. These results may show that DJB improve glucose tolerance in very early postoperative period as the result of glucose accumulation in the AL because of changes in glucose transporter expression.

Comparison of the Outcomes of Single Anastomosis Duodeno-Ileostomy with Sleeve Gastrectomy (SADI-S), Single Anastomosis Sleeve Ileal (SASI) Bypass with Sleeve Gastrectomy, and Sleeve Gastrectomy Using a Rodent Model with Diabetes

OBJECTIVE

Single anastomosis duodeno-ileostomy with sleeve gastrectomy (SADI-S) is a powerful form of bariatric surgery; however, it has a high risk of malnutrition. Single anastomosis sleeve ileal (SASI) bypass with sleeve gastrectomy may be used as an alternative procedure to avoid malnutrition associated with SADI-S; however, no comparison between the two procedures has been performed.

METHODS

Sprague-Dawley rats with diabetes (n = 32) were divided into four groups: SADI-S (n = 8), SASI (n = 8), SG (n = 8), and SHAM (n = 8). Body weight, food intake, and fasting blood glucose were measured, and the oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were performed before and after surgery. Blood samples were collected before and after the surgery to assess the levels of glucagon-like peptide-1 (GLP-1), hemoglobin, albumin, vitamin B12, calcium, and iron.

RESULTS

The SADI-S and SASI groups showed significantly greater weight loss and better glucose control than the SG group postoperatively. The SADI-S and SASI groups showed similar improvements in glucose control throughout the study. The SADI-S and SASI groups had significantly higher GLP-1 levels than the SG group at 6 months. The SADI-S and SASI groups presented with various degrees of deficiencies, with the SADI-S group showing a higher risk for hypoalbuminemia and iron deficiency than the SASI group.

CONCLUSIONS

The SASI procedure may be a better alternative as it has excellent bariatric and metabolic results with lower risk for hypoalbuminemia and can be easily converted into either SADI-S or SG procedures. Nevertheless, further clinical results are needed.

Can we abandon foregut exclusion for an ideal and safe metabolic surgery?

Foregut (foregut exclusions) and hindgut (rapid transit of nutrients to the distal intestine) theories are the most commonly used explanations for the metabolic improvements observed after metabolic surgeries. However, several procedures that do not comprise duodenal exclusions, such as sleeve with jejunojejunal bypass, ileal interposition, and transit bipartition and sleeve gastrectomy were found to have similar diabetes remission rates when compared with duodenal exclusion procedures, such as gastric bypass, biliopancreatic diversion with duodenal switch, and diverted sleeve with ileal interposition. Moreover, the complete exclusion of the proximal intestine could result in the malabsorption of several important micronutrients. This article reviews commonly performed procedures, with and without foregut exclusion, to better comprehend whether there is a critical need to include foregut exclusion in metabolic surgery.

Comparing the Anti-diabetic Effect of Sleeve Gastrectomy with Transit Bipartition Against Sleeve Gastrectomy and Roux-en-Y Gastric Bypass Using a Diabetic Rodent Model

PURPOSE

Roux-en-Y gastric bypass (RYGB) has superior long-term diabetes remission outcomes to sleeve gastrectomy (SG). However, in regions with a high prevalence of gastric cancer, RYGB may not be the best option. This study aimed to investigate the anti-diabetic effect of SG with transit bipartition (SG-TB) compared with SG and RYGB.

MATERIALS AND METHODS

A total of 32 diabetic Sprague-Dawley rat models were assigned to one of four groups: SG (n = 8), RYGB (n = 8), SG-TB (n = 8), and SHAM (n = 8). Body weight, food intake, blood glucose, and hormonal changes (glucagon-like peptide-1 (GLP-1), insulin, and glucagon) were measured to investigate the effect of surgery in all groups. Oral glucose tolerance test and insulin tolerance test were performed before and 8 weeks after surgery.

RESULTS

There were no significant differences in the postoperative changes in body weight and food intake among the SG, RYGB, and SG-TB groups. Postoperatively, the RYGB and SG-TB groups had significantly higher GLP-1 levels and lower insulin levels than the SG group. Further, RYGB and SG-TB had significantly better glucose control improvements than SG. There were no significant differences in GLP-1, insulin, glucagon, and homeostasis model assessment of insulin resistance levels between RYGB and SG-TB. The preoperative and postoperative values of all variables in the SHAM group did not show significant differences.

CONCLUSION

In this study using a diabetes-induced rodent model, we found that the anti-diabetic effect of SG-TB is superior to that of SG and non-inferior to that of RYGB.

Absorbable suture can be effectively and safely used to close the mesenteric defect in a gastric bypass Sprague-Dawley rat model

Background

To observe if closing the mesenteric defect with absorbable sutures creates a safe adhesion compared to non-absorbable suture after Roux-en-Y gastric bypass.

Methods

Rats were randomly assigned to 5 experimental groups according to the different suture materials used in closing the mesenteric defects (Peterson’s space) after Roux-en-Y gastric bypass. Group A (control group), Group B (non-absorbable suture, Prolene suture), Group C (biological glue), Group D (non-absorbable suture, polyester suture) and Group E (absorbable suture). All rats were followed up for 8 weeks postoperatively and underwent laparotomy to observe the degree of adhesion and closure of the mesenteric defect.

Results

No significant difference was found in the decrease in food intake and body weight among all groups. No internal hernia (IH) occurred in any group. The mesenteric defects of Group A remained completely visible without any closure or adhesion. Multiple gaps were found between the Prolene suture and the mesentery along the suture line in Group B. The mesenteric defects of Group C were complete closed with multiple adhesions of the small intestine and the greater omentum. The mesenteric defects in both Group D and Group E closed completely. The average adhesion scores in Group A and Group B were 0 and 0.33 ± 0.52 respectively. The average adhesion score in group C (3.83 ± 0.41) was higher than the other groups (p<0.05). The average adhesion scores in Group D and E were similar (3.17 ± 0.41 and 3.00 ± 0.00 respectively).

Conclusion

Absorbable suture created a safe adhesion score between the mesentery which was not inferior to non-absorbable sutures.

The effect of distal-ileal exclusion after Roux-en-Y gastric bypass on glucose tolerance and GLP-1 response in type-2 diabetes Sprague-Dawley rat model

BACKGROUND

An increase in glucagon-like peptide-1 (GLP-1) mediating early diabetes remission after Roux-en-Y gastric bypass (RYGB) is believed to be associated with distal-ileal stimulation.

OBJECTIVE

To observe the effect of distal-ileal exclusion on glucose tolerance and GLP-1 response after RYGB.

SETTING

Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu, China.

METHODS

A type 2 diabetes model was created in 40 Sprague-Dawley rats that were randomly assigned to a RYGB group (n = 32) and a sham group (n = 8). Four weeks after surgery, the RYGB group was further divided into the RYGB control group (n = 8) and the distal-ileal exclusion group (RYGB-IEx, n = 24). Rats in the RYGB-IEx group underwent laparotomy, and the last 20 cm of ileum was excluded. An oral glucose tolerance test, insulin tolerance test, and mixed-meal tolerance test conducted preoperatively were repeated in all groups at 4 and 8 weeks postoperatively.

RESULTS

Compared with preoperative level, GLP-1 was significantly increased after RYGB. GLP-1 area under the curve recorded after oral gavage at week 4 postoperatively was significantly higher than the preoperative level (P < .05). GLP-1, insulin area under the curve, and improved glucose-excursion on oral glucose tolerance test 4 weeks after gastric bypass were not reversed at week 8 after distal-ileal exclusion in the RYGB-IEx group. Food intake increased significantly after distal-ileal exclusion in the RYGB-IEx group.

CONCLUSION

These findings suggest that distal-ileal stimulation might not be required for incretin response and diabetes remission after gastric bypass in the type 2 diabetes Sprague-Dawley rat model.