Additional effects of duodenojejunal bypass on glucose metabolism in a rat model of sleeve gastrectomy

Intestinal glucose excretion: A potential mechanism for glycemic control

The gut has been increasingly recognized in recent years as a pivotal organ in the maintenance of glucose homeostasis. Specifically, the profound and enduring improvement in glucose metabolism achieved through metabolic surgery to modify the anatomy of the gut has prompted scholars to acknowledge that the most effective strategy for treating type 2 diabetes mellitus (T2DM) involves the gut. The mechanisms underlying the regulation of glucose metabolism by the gut encompass gut hormones, bile acids, intestinal gluconeogenesis, gut microbiota, and signaling interactions between the gut and other organs (liver, brain, adipose, etc.). Recent studies have also revealed a novel phenomenon of glucose lowering through the gut: metabolic surgery and metformin promote the excretion of glucose from the circulation into the intestinal lumen by enterocytes. However, there is still limited understanding regarding the underlying mechanisms of intestinal glucose excretion and its contribution to glycemic control. This article reviews current research on intestinal glucose excretion while focusing on its role in T2DM management as well as potential mechanisms.

Transcriptome Changes and Metabolic Outcomes After Bariatric Surgery in Adults With Obesity and Type 2 Diabetes

Context

Bariatric surgery has been shown to be effective in inducing complete remission of type 2 diabetes in adults with obesity. However, its efficacy in achieving complete diabetes remission remains variable and difficult to predict before surgery.

Objective

We aimed to characterize bariatric surgery-induced transcriptome changes associated with diabetes remission and the predictive role of the baseline transcriptome.

Methods

We performed a whole-genome microarray in peripheral mononuclear cells at baseline (before surgery) and 2 and 12 months after bariatric surgery in a prospective cohort of 26 adults with obesity and type 2 diabetes. We applied machine learning to the baseline transcriptome to identify genes that predict metabolic outcomes. We validated the microarray expression profile using a real-time polymerase chain reaction.

Results

Sixteen patients entered diabetes remission at 12 months and 10 did not. The gene-expression analysis showed similarities and differences between responders and nonresponders. The difference included the expression of critical genes (SKT4, SIRT1, and TNF superfamily), metabolic and signaling pathways (Hippo, Sirtuin, ARE-mediated messenger RNA degradation, MSP-RON, and Huntington), and predicted biological functions (β-cell growth and proliferation, insulin and glucose metabolism, energy balance, inflammation, and neurodegeneration). Modeling the baseline transcriptome identified 10 genes that could hypothetically predict the metabolic outcome before bariatric surgery.

Conclusion

The changes in the transcriptome after bariatric surgery distinguish patients in whom diabetes enters complete remission from those who do not. The baseline transcriptome can contribute to the prediction of bariatric surgery-induced diabetes remission preoperatively.

Changes of Short-Chain Fatty Acids and Their Receptors in an Obese Rat Model After Sleeve Gastrectomy

BACKGROUND

Short-chain fatty acids (SCFAs) and gut microbiota have health-related effects and are associated with a wide range of disorders. However, the changes of SCFAs and their receptors after sleeve gastrectomy (SG) remain unclear. This study aimed to examine changes of SCFAs and their receptors after SG in an obese rat model.

METHODS

Thirty obese Sprague-Dawley rats eating a high-energy diet for 6 weeks were divided into three groups: sham-operated (SO) control, pair-fed (PF) control, and SG group. Six weeks after the surgery, metabolic parameters, SCFA levels in the blood and stool, mRNA and protein expression of SCFA receptors in the ileum and epididymal fat, and gut microbiota were examined.

RESULTS

Metabolic parameters in the SG group were significantly improved compared with the SO group. Acetic acid levels in the blood and stool were significantly higher in the SG group than the PF group. The butyric acid level in the stool was also significantly higher in the SG group than in the PF group. In the ileum and epididymal fat, mRNA and protein expression of GPR41 was significantly higher in the SG group than in the other two groups, and mRNA and protein expression of GPR43 was significantly higher in the SG group than in the PF group. Increases in the genera Enterococcus, Lactobacillus, Lactococcus, and Clostridium were observed in the stool after SG.

CONCLUSIONS

SG may activate SCFA pathways through a change in gut microbiota.

Role of Proximal Intestinal Glucose Sensing and Metabolism in the Blood Glucose Control in Type 2 Diabetic Rats After Duodenal Jejunal Bypass Surgery

BACKGROUND

Although gastric surgery can significantly improve blood glucose homeostasis in type 2 diabetes mellitus (T2DM), its mechanism remains unclear. This study evaluated the role of intestinal glucose sensing, glucose transport, and metabolism in the alimentary limb (A limb) of T2DM rats after duodenal jejunal bypass (DJB) surgery.

METHODS

A T2DM rat model was induced via a high-glucose high-fat diet and low-dose streptozotocin injection. The diabetic rats were divided into two groups: the DJB surgery (T2DM-DJB) group and the sham surgery (T2DM-Sham) group. Wistar rats were used as wild-type control (Control). Small animal PET was used to assess the change in glucose metabolic status in the intestine. The intestinal villi height and the number of EECs after DJB were evaluated. The expressions of sweet taste receptors (T1R2/T1R3), glucose transporters (SGLT1/GLUT2), and key enzymes involved in glucose metabolism (HK2, PFK2, PKM2, G6Pase, and PCK1) in the A limb after DJB was detected by Western blot and qRT-PCR.

RESULTS

Small animal PET analysis showed the intestinal glucose metabolism increased significantly 6 weeks after DJB surgery. The intestinal villi height and the number of EECs in the A limb 6 weeks after surgery increased significantly in T2DM-DJB rats comparing to T2DM-Sham rats. The mRNA and protein expression of T1R1/T1R3 and SGLT1/GLUT2 were downregulated in DJB-T2DM rats, while enzymes involved in glucose metabolism was upregulated in the A limb in T2DM-DJB rats.

CONCLUSION

Proximal intestinal glucose sensing and metabolism play an important role in blood glucose homeostasis by DJB.

Single-Anastomosis Duodenal Switch: Conceptual Difference between East and West

Single-anastomosis duodenal switch (SADS) has become increasingly popular. This review compared the conceptual difference between Eastern (SADS-E) and Western (SADS-W) countries. After searching for SADS through PubMed and high-impact journals, 19 articles with 2280 patients were included for analysis. We found SADS-W was reserved for patients with a high body mass index (BMI) without type 2 diabetes mellitus (T2DM). Surgeons performing SADS-W used larger bougies and preferred shorter common channels. However, SADS-E was mainly preferred in T2DM patients with a low BMI. SADS-E bypassed less bowel and used smaller bougies. The spectra of major postoperative complications, nutritional deficiencies, and gastrointestinal disorders were different between SADS-E and SADS-W. SADS-W yielded better weight loss and better T2DM remission than SADS-E. SADS are effective bariatric and metabolic procedures with promising therapeutic outcomes and acceptable safety.