The effect of duodenojejunostomy and sleeve gastrectomy on type 2 diabetes mellitus and gastrin secretion in Goto-Kakizaki rats

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.

Gastrin: a new branch of the gastropancreatic axis that can explain the effect of sleeve gastrectomy on glucose metabolism

BACKGROUND

Among bariatric techniques, sleeve gastrectomy (SG) stands out owing to its efficiency. The role of the stomach as a secretory organ of many substances, such as gastrin, related to insulin secretion is well known. Gastrin induces insulin release in isolated pancreatic islets, limiting somatostatin-14 intraislet release, and has been associated with blood glucose level improvement in diabetic models after SG. SG involves gastric resection along the greater curvature. This study aimed to determine the role of gastrin in glucose metabolism improvement after SG with the aid of the gastrin antagonist netazepide.

METHODS

In 12 sham-operated, 12 SG-operated, and 12 SG-operated/netazepide-treated Wistar rats, we compared medium- and long-term plasma insulin, oral glucose tolerance test (OGTT) results, and plasma gastrin levels. In addition, gastrin expression was assessed in the gastric remnant, and the beta-cell mass was measured.

RESULTS

SG induced a medium-term elevation of the insulin response and plasma gastrin levels without modification of the OGTT results. However, long-term depletion of the insulin response with elevated OGTT areas under the curve and plasma gastrin levels appeared after SG. Netazepide prevented the SG effect on these parameters. Gastrin tissue expression was greater in SG animals than in SG/netazepide-treated or control animals. The beta-cell mass was lower in the SG group than in the control or SG/netazepide group.

CONCLUSION

Gastrin plays a central role in glucose improvement after SG. It stimulates a medium-term strong insulin response but also causes long-term beta-cell mass depletion and a loss of insulin response. These effects are prevented by gastrin antagonists such as netazepide.

Weight and Glucose Control in Rats Submitted to Sleeve Gastrectomy with Cafeteria Diet-Induced Obesity

Introduction: Sleeve gastrectomy (SG) has been widely disseminated as a surgical treatment for obesity and associated comorbidities, and currently it is one of the most performed surgeries in the world. Experimental research is becoming increasingly relevant to characterize the pathophysiological mechanisms induced by it. Objective: The aim of this study was to standardize an experimental model of SG in rats with obesity induced using a cafeteria diet (CAF) and evaluate variations in weight and glycemic control after vertical SG, maintaining the CAF. Materials and Methods: Twenty Rattus norvegicus albinus rats, Wistar strain, with an average weight of 250 g were used. The animals were randomized into two groups and underwent 4 weeks of obesity induction before the procedure. In 10 animals of the SG group, vertical SG was performed, and in 10 animals of the control/sham (C) group, simulated surgery was performed, consisting of laparotomy and bidigital compression of the stomach. The animals were followed for a total of 8 weeks, with the weight assessed weekly and fasting blood glucose assessed before the start of the CAF, at the time of surgery, and after 4 weeks of the postoperative period, when they were sacrificed. Results: Before obesity induction, the average weight was 257.8 g in the SG group 266.1 g in the C group. After obesity induction, the average weight was 384 g in the vertical sleeve gastrectomy group and 374.8 g in the C group. In the fourth postoperative week, the average weight was 391.6 g in the VSG group and 436.6 g in the C group. The average blood glucose levels were 88.7, 101.8, and 91.3 mg/dL in the VSG group and 86.6, 103.1, and 109.4 mg/dL in the C group, respectively, before the start of the diet, in the fourth preoperative week, and in the fourth postoperative week. Conclusions: Vertical SG in rats is feasible and promotes glycemic control in the postoperative period. CAF allows induction of obesity and changes in blood glucose.

Mechanisms of bariatric surgery for weight loss and diabetes remission

Obesity and type 2 diabetes(T2D) lead to defects in intestinal hormones secretion, abnormalities in the composition of bile acids (BAs), increased systemic and adipose tissue inflammation, defects of branched-chain amino acids (BCAAs) catabolism, and dysbiosis of gut microbiota. Bariatric surgery (BS) has been shown to be highly effective in the treatment of obesity and T2D, which allows us to view BS not simply as weight-loss surgery but as a means of alleviating obesity and its comorbidities, especially T2D. In recent years, accumulating studies have focused on the mechanisms of BS to find out which metabolic parameters are affected by BS through which pathways, such as which hormones and inflammatory processes are altered. The literatures are saturated with the role of intestinal hormones and the gut-brain axis formed by their interaction with neural networks in the remission of obesity and T2D following BS. In addition, BAs, gut microbiota and other factors are also involved in these benefits after BS. The interaction of these factors makes the mechanisms of metabolic improvement induced by BS more complicated. To date, we do not fully understand the exact mechanisms of the metabolic alterations induced by BS and its impact on the disease process of T2D itself. This review summarizes the changes of intestinal hormones, BAs, BCAAs, gut microbiota, signaling proteins, growth differentiation factor 15, exosomes, adipose tissue, brain function, and food preferences after BS, so as to fully understand the actual working mechanisms of BS and provide nonsurgical therapeutic strategies for obesity and T2D.

Clinical Outcomes of Resectional Roux-en-Y Gastric Bypass, Compared to Sleeve Gastrectomy for Severe Obesity

PURPOSE

Resectional Roux-en-Y gastric bypass (RRYGB) is considered an alternative bariatric surgery in countries with a high incidence of stomach cancer because there is no excluded stomach after RRYGB. This study aimed to evaluate the efficacy and safety of RRYGB.

MATERIALS AND METHODS

This study included patients who underwent RRYGB and sleeve gastrectomy (SG) between 2011 and 2021. Surgical complications and metabolic and nutritional profiles were compared between the patients preoperatively and at 1, 6, and 12 months after surgery.

RESULTS

Twenty and seventy-six patients underwent RRYGB and SG, respectively; 7 in the SG group were lost to follow-up within 1 year. Surgical complications and baseline characteristics were comparable between two groups, except for diabetes (90.0% vs. 44.7%, p < 0.001). The decrease of HbA1c levels and incidence of reflux esophagitis were lower in the RRYGB group compared to that of SG at 1-year postoperative (-3.0% vs. -1.8%, p = 0.014; 0% vs. 26.7%, p = 0.027). The percentage of total weight loss at 1- year postoperative and incidence of dumping syndrome were comparable between the two groups. The RRYGB group had significantly lower total cholesterol level (161.9 mg/dl vs. 196.4 mg/dl, p < 0.001), but higher incidence of vitamin B12 deficiency (30.0% vs. 3.6%, p = 0.003) at 1 year postoperative compared to those of the SG group.

CONCLUSIONS

The RRYGB group had better postoperative outcomes for diabetes and dyslipidemia without increasing surgical complications compared to that of the SG group. Thus, RRYGB can be considered a safe and effective alternative in areas where gastric cancer is prevalent.

NFAT5 Is Involved in GRP-Enhanced Secretion of GLP-1 by Sodium

Gastrin, secreted by G-cells, and glucagon-like peptide-1 (GLP-1), secreted by L-cells, may participate in the regulation of sodium balance. We studied the effect of sodium in mice in vivo and mouse ileum and human L-cells, on GLP-1 secretion, and the role of NFAT5 and gastrin-releasing peptide receptor (GRPR) in this process. A high-sodium diet increases serum GLP-1 levels in mice. Increasing sodium concentration stimulates GLP-1 secretion from mouse ileum and L-cells. GRP enhances the high sodium-induced increase in GLP-1 secretion. High sodium increases cellular GLP-1 expression, while low and high sodium concentrations increase NFAT5 and GRPR expression. Silencing NFAT5 in L-cells abrogates the stimulatory effect of GRP on the high sodium-induced GLP-1 secretion and protein expression, and the sodium-induced increase in GRPR expression. GLP-1 and gastrin decrease the expression of Na⁺-K⁺/ATPase and increase the phosphorylation of sodium/hydrogen exchanger type 3 (NHE3) in human renal proximal tubule cells (hRPTCs). This study gives a new perspective on the mechanisms of GLP-1 secretion, especially that engendered by ingested sodium, and the ability of GLP-1, with gastrin, to decrease Na⁺-K⁺/ATPase expression and NHE3 function in hRPTCs. These results may contribute to the better utilization of current and future GLP-1-based drugs in the treatment of hypertension.

Dipeptidyl peptidase-4 activity, lipopolysaccharide, C-reactive protein, glucose metabolism, and gut peptides 3 months after bariatric surgery

BACKGROUND

Bariatric surgery induces weight loss, but changes in glucose metabolism, gut peptides, and inflammatory biomarkers still have conflicting results.

SETTINGS

University hospital.

OBJECTIVES

We investigated glucose metabolism, gut hormones, and inflammatory profile after bariatric surgery and medical treatment.

METHODS

Forty patients with obesity were recruited and were subjected to Roux-en-Y gastric bypass (n = 15; Bariatric Surgery Group - BSG) or received medical care (n = 20; MG). Sleeve gastrectomy was performed in five patients who were excluded from analysis. Glucose, insulin, homeostatic model for the assessment of insulin resistance (HOMA-IR), glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), glucagon, ghrelin, dipeptidyl peptidase-4 (DPP-4) activity, circulating lipopolysaccharide (LPS), LPS-binding protein (LPB) and high-sensitivity C-reactive protein (hs-CRP) were evaluated before and three months after each treatment. Except for HOMA-IR, hs-CRP, and LBP, all variables were assessed at fasting and 30- and 60-minutes after a standard meal.

RESULTS

After 3 months, both groups lost weight. However, BSG had a more extensive reduction than MG (respectively, 17.6% vs. 4.25%; P < 0.01). Except for LPS levels, higher on BSG than MG (1.38 ± 0.96 vs. 0.83 ± 0.60 EU/ml, P < 0.01), groups were similar before treatment. In respect to metabolic/hormonal changes, the BSG showed higher glucose, insulin, GLP-1, and GIP levels at 30-min and also GLP-1 at 30- and 60-minutes. DPP-4 activity, HOMA-IR, and fasting LBP did not change. LPS levels at 60-minutes decreased after surgery in the BSG. hs-CRP decreased on BSG compared to MG.

CONCLUSIONS

Bariatric surgery resulted in more extensive effects on glucose metabolism, gut hormones, and inflammation.

VERTICAL GASTRECTOMY VS. EXTENDED VERTICAL GASTRECTOMY: WHAT IS THE IMPACT ON GASTROESOPHAGEAL REFLUX DISEASE IN OBESE RATS?

BACKGROUND

Extended vertical gastrectomy is a variation of the vertical gastrectomy technique requiring studies to elucidate safety in relation to gastroesophageal reflux.

AIM

To analyze comparatively vertical gastrectomy (VG) and extended vertical gastrectomy (EVG) in rats with obesity induced by cafeteria diet in relation to the presence of reflux esophagitis, weight loss and macroscopic changes related to the procedures.

METHODS

Thirty Wistar rats were randomized into three groups, and after the obesity induction period by means of a 28-day cafeteria diet, underwent a simulated surgery (CG), VG and VGA. The animals were followed up for 28 days in the post-operative period, and after euthanasia, the reflux esophagitis evaluation was histopathologically performed. Weight and macroscopy were the other variables; weight was measured weekly and the macroscopic evaluation was performed during euthanasia.

RESULTS

All animals presented some degree of inflammation and the presence of at least one inflammation criterion; however, there was no statistically significant difference in the analysis among the groups. In relation to weight loss, the animals in CG showed a gradual increase during the whole experiment, evolving to super-obesity at the end of the study, while the ones with VG and EVG had weight regain after the first post-operative period; however, a less marked regain compared to CG, both for VG and EVG.

CONCLUSION

There is no difference in relation to reflux esophagitis VG and EVG, as well as macroscopic alterations, and both techniques have the ability to control the evolution of weight during postoperative period in relation to CG.

High Resected Gastric Volume and poorly controlled DM2 in laparoscopic sleeve gastrectomy

Background

Our aim is to evaluate the effects of High Resected Gastric Volume(HRGV) on poorly Type 2 Diabetes Mellitus(DM2) after Laparoscopic Sleeve Gastrectomy(LSG).

Methods

256 patients were divided into two groups according to the RGV: < 1500 mL(Group A: 131 pts) and > 1500 mL(Group B: 147 pts). % excess body mass index loss (%EBMIL), Fasting Blood Glucose (FBG), HbA1c, C peptide were assessed before surgery and at the 3rd day, 6th,12th,24th,36th month after LSG.

Results

A significant difference in %EBMIL between the two groups at 24 and 36 months was found. RGV was not significantly associated with DM2 in the multivariate logistic regression. FBG levels showed no differences between the two groups. A significant decrease of Hb1Ac at 6 and 12 months was found in group B. The C-peptide level showed a significant reduction at 6 and 12 months in group B.

Conclusion

The HRGV may play a role in the regulation of the glucose metabolism in the first year after LSG without influence in poorly DM2 control. Further studies are needed to confirm these findings.

Which is the correlation between carcinoid tumor and Laparoscopic Sleeve Gastrectomy? A case series and literature review

Introduction

Gastric Carcinoid Tumors (GCT) are very rare in general population, but some studies evidenced a higher incidence among bariatric surgery patients. Laparoscopic Sleeve Gastrectomy (LSG) is a widely accepted procedure for the surgical treatment of morbid obesity. LSG acts both in reducing food intake and interfering with hormonal balance in the gut-brain axis. In these patients, incidental GCT diagnosis can occur both during pre-bariatric surgery investigation and during post-operative follow-up.

Methods

We retrospectively analyzed the database of obesity patients submitted to LSG in two different centers to find out incidence of GCT in patients treated by surgery from May 2013 to March 2018.

Results

From the 560 obese consecutive patients underwent LSG, we recorded two cases of patients with GCT (0.36%): the case 1 was a patient who had a pre-operative diagnosis of GTC receiving a curative LSG which totally included the carcinoid in the resected portion; the case 2 was a patient that received a curative endoscopic resection 42 months after LSG.

Discussion

the predisposing factors that can correlate GCT with obesity and LSG and in particular the hormonal changes have been discussed. We illustrated our experience about the management of these tumors in obese patients.

Conclusion

there are neither certain data which evidence a correlation between obesity and GCT, nor data to support the hypothesis of a higher incidence of GCT after bariatric surgery. Based on our experience in obese patients the finding of GCT in the pre-operatory phase is not an absolute contraindication for bariatric surgery.

•

Recent observations showed a high incidence of Gastric Carcinoid Tumor (GCT) in candidate patients for bariatric surgery.

•

From a multicenter experience with Laparoscopic Sleeve Gastrectomy.

•

We retrospectively recorded two GCT cases in obese patients (the first found out during pre-operative investigations and the second one detected 52 months after surgery).

•

The possible correlations between obesity, LSG and GTC have been discussed.

The effect of hypergastrinemia following sleeve gastrectomy and pantoprazole on type 2 diabetes mellitus and beta-cell mass in Goto-Kakizaki rats

PURPOSE

Metabolic surgery alters the secretion of gastrointestinal hormones that influence glycemic control. Elevated gastrin has been suggested to benefit patients with type 2 diabetes and has been reported following sleeve gastrectomy in rats. The present study compares the effect of hypergastrinemia following sleeve gastrectomy with proton-pump inhibitor therapy on glycemic control and beta-cell mass in lean, diabetic animals.

METHODS

Thirty-three diabetic Goto-Kakizaki rats were randomized into pantoprazole + sham operation (GK-PPI), sleeve gastrectomy (GK-SG) and vehicle + sham operation (GK-V). Body weight, glucose parameters, HbA1c, glucagon-like peptide 1, gastrin, insulin and lipids were evaluated for eighteen postoperative weeks. Total beta-cell mass was quantified by optical projection tomography.

RESULTS

After surgery, body weight development was equal among groups (P _g = 0.75). Fasting and stimulated gastrin increased for GK-PPI and GK-SG vs. GK-V (p < 0.05 for all). Fasting blood glucose was decreased for GK-PPI and GK-SG vs. GK-V (p < 0.05 and p = 0.052). HbA1c was lower for GK-SG vs. GK-V at 6 weeks and for GK-PPI vs. GK-V at twelve- and eighteen weeks postoperative (p < 0.05 for all); a borderline difference was observed for GK-SG vs. GK-V at 18 weeks (p = 0.054). Total- and LDL cholesterol was elevated for GK-PPI compared to the other two groups (p < 0.05 for all). Beta-cell mass did not differ among groups (p = 0.35).

CONCLUSIONS

Hypergastrinemia following sleeve gastrectomy and pantoprazole has a similar, modest effect on glycemic control in Goto-Kakizaki rats but does not enhance beta-cell mass after 18 weeks. Hypergastrinemia in the setting of T2DM might be of clinical relevance.

Incidence and treatment of metachronous gastric cancer after proximal gastrectomy

BACKGROUND AND PURPOSE

Proximal gastrectomy (PG) is a widely accepted function-preserving surgical procedure; however, the incidence and treatment of metachronous gastric cancer (MGC) after PG have been the subject of a number of reports.

METHODS

We collected data from 1576 consecutive patients who underwent gastrectomy for gastric cancer between January, 2003 and December, 2010, and analyzed the outcomes of 671 patients treated with PG or distal gastrectomy (DG) for cT1N0 disease. We also discuss the treatments for MGC.

RESULTS

MGC was diagnosed within a median follow-up of 52.8 months after PG and DG in six (6.6%) and nine (1.8%) patients, respectively. The cumulative prevalence of MGC after PG was significantly higher than that after DG; P = 0.005. Univariate and multivariate analysis revealed male sex and PG as significant risk factors for MGC (P = 0.014 and P = 0.026, respectively). Five of the six patients who underwent PG were treated by endoscopic submucosal dissection.

CONCLUSIONS

The incidence of MGC after PG was significantly higher than that after DG. However, most of the MGCs that developed after PG could be treated by endoscopic submucosal dissection.

Potential Hormone Mechanisms of Bariatric Surgery

PURPOSE OF REVIEW

In recent years, the role of the gastrointestinal (GI) tract in energy homeostasis through modulation of the digestion and absorption of carbohydrates and the production of incretin hormones is well recognized.

RECENT FINDINGS

Bariatric surgery for obesity has been a very effective method in substantially improving weight, and numerous studies have focused on intestinal adaptation after bariatric procedures. A number of structural and functional changes in the GI tract have been reported postsurgery, which could be responsible for the altered hormonal responses. Furthermore, the change in food absorption rate and the intestinal regions exposed to carbohydrates may affect blood glucose response. This review hopes to give new insights into the direct role of gut hormones, by summarising the metabolic effects of bariatric surgery.

Lean, but not healthy: the 'metabolically obese, normal-weight' phenotype

PURPOSE OF REVIEW

Obesity is commonly associated with metabolic dysfunction but there are obese persons who are metabolically healthy. On the opposite side of the coin, there are lean persons who carry multiple cardiometabolic risk factors, typically referred to as metabolically obese, normal-weight (MONW). This has called into question our understanding of obesity and metabolic dysfunction, as an appearance of normal weight may mask significant comorbidities and delay health interventions.

RECENT FINDINGS

High heterogeneity in MONW prevalence rates has been observed, with estimates ranging from as low as 5% to as high as 45%. Reasons for this include sample size effects, differences in MONW definition, social and demographic factors, as well as assumptions made in establishing normal weight. MONW study participants are often characterized by excess visceral adipose tissue and ectopic fat deposition, adipose tissue inflammation, altered inflammatory and adipokine profiles, reduced skeletal muscle mass and low cardiorespiratory fitness. However, more often than not, groups of MONW study participants have been somewhat 'fatter' than the control groups of metabolically healthy lean study participants, which in itself could be responsible for some of the observed differences. Very limited data are available regarding interventions to improve metabolic function in MONW study participants.

SUMMARY

There is a need for more research to better understand the characteristics of the MONW phenotype, the cause of metabolic dysfunction in the absence of obesity, and evaluate potential therapies so as to facilitate the establishment of clinical guidelines.

The effect of bariatric surgery on gastrointestinal and pancreatic peptide hormones

Bariatric surgery for obesity has proved to be an extremely effective method of promoting long-term weight reduction with additional beneficial metabolic effects, such as improved glucose tolerance and remission of type 2 diabetes. A range of bariatric procedures are in common use, including gastric banding, sleeve gastrectomy and the Roux-en-Y gastric bypass. Although the mechanisms underlying the efficacy of bariatric surgery are unclear, gastrointestinal and pancreatic peptides are thought to play an important role. The aim of this review is to summarise the effects of different bariatric surgery procedures upon gastrointestinal and pancreatic peptides, including ghrelin, gastrin, cholecystokinin (CCK), glucose-dependent insulinotropic hormone (GIP), glucagon-like peptide 1 (GLP-1), peptide YY (PYY), oxyntomodulin, insulin, glucagon and somatostatin.

Metabolic surgery: A paradigm shift in type 2 diabetes management

Obesity and type 2 diabetes mellitus (T2DM) are major public health issues globally over the past few decades. Despite dietary interventions, lifestyle modifications and the availability of several pharmaceutical agents, management of T2DM with obesity is a major challenge to clinicians. Metabolic surgery is emerging as a promising treatment option for the management of T2DM in the obese population in recent years. Several observational studies and a few randomised controlled trials have shown clear benefits of various bariatric procedures in obese individuals in terms of improvement or remission of T2DM and multiple other health benefits such as improvement of hypertension, obstructive sleep apnoea, osteoarthritis and non-alcoholic fatty liver disease. Uncertainties about the long-term implications of metabolic surgery such as relapse of T2DM after initial remission, nutritional and psychosocial complications and the optimal body mass index for different ethnic groups exist. The article discusses the major paradigm shift in recent years in the management of T2DM after the introduction of metabolic surgery.

Relationship between gastric pouch and weight loss after laparoscopic sleeve gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is considered safe and effective even as conversion procedure after primary bariatric operations. The correlation between gastric pouch volumes and patients weight loss remains unclear.

METHODS

To assess a correlation between the gastric remnant size and the weight loss, we reviewed 49 consecutive barium swallow UGS performed at our institute from August 2012 through May 2014 in LSG patients with symptoms and/or unsatisfactory weight loss. The anteroposterior (AP), laterolateral (LL) and vertical (CC) diameters of the gastric pouch were measured to calculate the volume by the formula of the ellipsoid (AP × LL × CC × 0.5). Patients were divided in two groups: group 1 without gastric pouch (n = 36) and group 2 with gastric pouch (n = 13). Correlation between pouch volume and weight loss data was calculated with t Student's and Fisher tests to compare the percent excess body mass index (BMI) and percent excess body mass loss (EBL) between two groups, and P < 0.05 was considered statistically significant.

RESULTS

The mean percent EBL was 26.54 ± 11.02 and 27.12 ± 12.35 kg/m(2) in groups with and without pouch, respectively. The mean volume of the pouch after LSG was 17.13 ± 21.56 mm(3). Pouch volume, when present, was not significantly correlated to weight loss (P = 0.88 95% CI, CL 19.88-33.20 group 2; CL 22.94-31.30 group 1).

CONCLUSIONS

No statistical correlation was found between the volume of the gastric pouch and weight loss (percent EBL) after LSG in symptomatic or with unsatisfactory weight loss patients.

Peripheral signals mediate the beneficial effects of gastric surgery in obesity

Obesity is nowadays a public health problem both in the industrialized world and developing countries. The different treatments to fight against obesity are not very successful with the exception of gastric surgery. The mechanism behind the achievement of this procedure remains unclear although the modifications in the pattern of gastrointestinal hormones production appear to be responsible for the beneficial effect. The gastrointestinal tract has emerged in the last time as an endocrine organ in charge of response to the different stimulus related to nutritional status by the modulation of more than 30 signals acting at central level to modulate food intake and body weight. The production of some of these gastric derived signals has been proved to be altered in obesity (ghrelin, CCK, and GLP-1). In fact, bariatric surgery modifies the production of both gastrointestinal and adipose tissue peripheral signals beyond the gut microbiota composition. Through this paper the main peripheral signals altered in obesity will be reviewed together with their modifications after bariatric surgery.