Enhanced Intestinal Motility during Oral Glucose Tolerance Test after Laparoscopic Sleeve Gastrectomy: Preliminary Results Using Cine Magnetic Resonance Imaging

Gastrointestinal Permeability After Bariatric Surgery: A Systematic Review

Gastrointestinal permeability refers to the movement of substances across the gut wall. This is mediated by endotoxemia (bacterial products entering the systemic circulation), and is associated with metabolic disease. The effect of bariatric surgery on permeability remains uncertain; the associated dietary, metabolic and weight changes are suggested to influence, or trigger, altered permeability. The primary aim of this study is to synthesize evidence and analyze the effect of bariatric surgery on permeability. A systematic review was performed, searching MEDLINE, EMBASE, and Scopus until February 2023, using MESH terms "intestinal permeability", "bariatric", for studies reporting in vivo assessment of permeability. Three cohort studies and two case series were identified (n=96). Data was heterogeneous; methodology and controls preclude meta-analysis. Gastroduodenal permeability reduced post-sleeve gastrectomy (SG). Two studies showed an increase in small intestinal permeability after biliopancreatic diversion. Two studies revealed a decrease in post-Roux-en-Y gastric bypass. One study identified increased colonic permeability six months post-SG. Evidence regarding permeability change after bariatric surgery is conflicting, notably for the small intestine. Impaired colonic permeability post-SG raises concerns regarding colonic protein fermentation and harmful dietary sequelae. There are multiple interacting variables confounding gastrointestinal permeability change; procedure type, altered microbiota and metabolic response to surgery. Further understanding of this important aspect of obesity is required, both before and after bariatric surgery.

Bariatric surgery and the neurohormonal switch: Early insulin resistance recordings after laparoscopic sleeve gastrectomy

Laparoscopic sleeve gastrectomy (LSG) is a bariatric operation with a safe risk profile. It has been proven to successfully reduce weight, decrease insulin resistance (IR), and ameliorate diabetes mellitus. The aim of this study was to determine if there is an early improvement in IR after LSG and its association with weight loss. This was a prospective observational study of 32 patients who underwent LSG at a single center over a 3-year period. Serum insulin and fasting glucose levels were recorded preoperatively, on day 1 postoperatively, and 3 weeks after LSG. IR levels were calculated using the Homeostasis Model Assessment 2 Version 2.23. IR levels were compared along with the overall weight loss, via body mass index. β-cell function was the secondary outcome. IR significantly improved the day after surgery with a statistically significant mean difference of 0.89 units (P = .043) and significantly more so 3 weeks postoperatively, with a mean difference of 4.32 units (P < .0005). β-cell function reduced 3 weeks postoperatively, with a mean difference of 23.95 %β (P = .025), while body mass index significantly reduced, with a mean difference of 4.32 kg/m2 (P < .0005). Early improvement of IR was observed on postoperative day 1 after LSG before any weight loss. This raises the possibility of an undetermined, underlying neurohormonal switch that improves IR. Further investigation is needed to determine this mechanism, as it may lead to an improvement in the medical management of diabetes mellitus.

Nutrients handling after bariatric surgery, the role of gastrointestinal adaptation

Bariatric surgery determines a rearrangement of the gastrointestinal tract that influences nutrient handling and plays a role in the metabolic changes observed after surgery. Most of the changes depend on the accelerated gastric emptying observed in Roux-en-Y gastric bypass (RYGB) and, to a lesser extent, in sleeve gastrectomy (SG). The rapid delivery of meal into the jejunum, particularly after RYGB, contributes to the prompt appearance of glucose in peripheral circulation. Glucose increase is the principal determinant of GLP-1 increase with the consequent stimulation of insulin secretion, the latter balanced by a paradoxical glucagon increase that stimulates EGP to prevent hypoglycaemia. Protein digestion and amino acid absorption appear accelerated after RYGB but not after SG. After RYGB, the adaptation of the gut to the new condition participates to the metabolic change. The intestinal transit is delayed, the gut microbioma is changed, the epithelium becomes hypertrophic and increases the expression of glucose transporter and of the number of cell secreting hormones. These changes are not observed after SG. After RYGB-less after SG-bile acids (BA) increase, influencing glucose metabolism probably modulating FXR and TGR5 with an effect on insulin sensitivity. Muscle, hepatic and adipose tissue insulin sensitivity improve, and the gut reinforces the recovery of IS by enhancing glucose uptake and through the effect of the BA. The intestinal changes observed after RYGB result in a light malabsorption of lipid but not of carbohydrate and protein. In conclusion, functional and morphological adaptations of the gut after RYGB and SG activate inter-organs cross-talk that modulates the metabolic changes observed after surgery.Level of evidence Level V, narrative literature review.

Serum Glucagon, Bile Acids, and FGF-19: Metabolic Behavior Patterns After Roux-en-Y Gastric Bypass and Vertical Sleeve Gastrectomy

BACKGROUND

Metabolic/bariatric surgery is a highly effective treatment for obesity and metabolic diseases. Serum glucagon, bile acids, and FGF-19 are key effectors of various metabolic processes and may play central roles in bariatric surgical outcomes. It is unclear whether these factors behave similarly after Roux-en-Y gastric bypass (RYGB) vs vertical sleeve gastrectomy (VSG).

METHODS

Serum glucagon, bile acids (cholic acid [CA], chenodeoxycholic acid [CDCA], deoxycholic acid [DCA]), and FGF-19 were analyzed in samples of fasting blood collected before bariatric surgery, on postoperative days 2 and 10, and at 3- and 6-month follow-up.

RESULTS

From September 2016 to July 2017, patients with obesity underwent RYGB or VSG; 42 patients (RYGB n = 21; VSG n = 21) were included in the analysis. In the RYGB group, glucagon, CA, and CDCA increased continuously after surgery (p = 0.0003, p = 0.0009, p = 0.0001, respectively); after an initial decrease (p = 0.04), DCA increased significantly (p = 0.0386). Serum FGF-19 was unchanged. In the VSG group, glucagon increased on day 2 (p = 0.0080), but decreased over the 6-month study course (p = 0.0025). Primary BAs (CA and CDCA) decreased immediately after surgery (p = 0.0016, p = 0.0091) and then rose (p = 0.0350, p = 0.0350); DCA followed the curve of the primary BAs until it fell off at 6 months (p = 0.0005). VSG group serum FGF-19 trended upward.

CONCLUSION

RYGB and VSG involve different surgical techniques and final anatomical configurations. Between postoperative day 2 and 6-month follow-up, RYGB and VSG resulted in divergent patterns of change in serum glucagon, bile acids, and FGF-19.

HIDA and Seek: Challenges of Scintigraphy to Diagnose Bile Reflux Post-Bariatric Surgery

INTRODUCTION

Oesophageal bile reflux after bariatric surgery may trigger development of Barrett's oesophagus. Gastro-oesophageal reflux of bile is captured by hepatobiliary iminodiacetic acid (HIDA) scintigraphy; however, anatomical and physiological changes after bariatric surgery warrant protocol modifications to optimise bile reflux detection.

METHODS

HIDA scintigraphy occurred 6 months after either sleeve gastrectomy, Roux-en-Y gastric bypass or one-anastomosis gastric bypass. Standard HIDA scanning involves (i) 6-h fast and 24-h abstinence from opioids; (ii) IV administration of 99mTc di-isopropyl iminodiacetic acid; and (iii) dual anterior/posterior 60-min dynamic scanning of the duodenum, stomach and oesophagus. Three challenges were identified, and modifications were implemented, namely, (1) anatomical localisation of refluxed bile on planar scintigraphy was improved by adding a SPECT/CT for 3D imaging; (2) impaired cholecystokinin-controlled gallbladder emptying, following bypassed duodenum, was addressed by ingestion of a 'fatty meal'; and (3) intestinal hypomotility after gastric bypass was counteracted by longer scan duration (75-90 min) to allow bile to pass beyond the gastro-jejunal anastomosis.

RESULTS

HIDA scan was undertaken in 18 patients, 13 of whom underwent the modified protocol. The tailored protocol ameliorated issues identified with the standard HIDA scan protocol; thus, accurate anatomical localisation was achieved in all patients, no delayed gallbladder emptying was observed, and bile was observed beyond the gastro-jejunal anastomosis in all gastric bypass patients. The modified technique was well tolerated by patients.

CONCLUSION

A tailored HIDA scan protocol with addition of a SPECT-CT scan, ingestion of a fatty meal and prolonged scanning duration results in enhanced bile reflux detection in post-bariatric surgical patients.

Alterations in Small Intestine and Liver Morphology, Immunolocalization of Leptin, Ghrelin and Nesfatin-1 as Well as Immunoexpression of Tight Junction Proteins in Intestinal Mucosa after Gastrectomy in Rat Model

The stomach is responsible for the processing of nutrients as well as for the secretion of various hormones which are involved in many activities throughout the gastrointestinal tract. Experimental adult male Wistar rats (n = 6) underwent a modified gastrectomy, while control rats (n = 6) were sham-operated. After six weeks, changes in small intestine (including histomorphometrical parameters of the enteric nervous plexuses) and liver morphology, immunolocalization of leptin, ghrelin and nesfatin-1 as well as proteins forming adherens and tight junctions (E-cadherin, zonula occludens-1, occludin, marvelD3) in intestinal mucosa were evaluated. A number of effects on small intestine morphology, enteric nervous system ganglia, hormones and proteins expression were found, showing intestinal enteroplasticity and neuroplasticity associated with changes in gastrointestinal tract condition. The functional changes in intestinal mucosa and the enteric nervous system could be responsible for the altered intestinal barrier and hormonal responses following gastrectomy. The results suggest that more complicated regulatory mechanisms than that of compensatory mucosal hypertrophy alone are involved.

Changes in bowel habits after laparoscopic sleeve gastrectomy

Introduction

Bariatric surgery has a significant impact on dietary intake, weight loss, patient’s metabolism and also on defaecation stereotypes.

Aim

To investigate changes in bowel habits of morbidly obese patients after laparoscopic sleeve gastrectomy (LSG).

Material and methods

This was a prospective clinical cohort study conducted to assess changes in bowel habits after LSG in a single institution.

Results

In total, 124 patients were enrolled in the study (age 47.1 ±11.2 years, body mass index (BMI) 44.3 ±6.8 kg/m²). The mean weight loss 6 months after LSG was 29.1 ±11.1 kg; percentage excess weight loss was 56.2 ±20.4%. Before surgery, 35.5% of patients had constipation and 6.5% of patients had faecal incontinence (FI). No correlation was found between rising level of BMI and constipation or incontinence prevalence/severity. Data analysis has not confirmed increased prevalence/severity of postoperative constipation or incontinence 6 months after LSG. Out of the group of patients with preoperative constipation, clinically relevant improvement was noted in 45.5% of patients after the surgery. Among patients without constipation before surgery, impairment was noted in 21.2% of patients. Out of the group of patients with preoperative incontinence, improvement was found in 37.5% of patients; none of these patients reported clinically relevant impairment of incontinence symptoms.

Conclusions

The present study has not revealed increased prevalence/severity of postoperative constipation or anal incontinence 6 months after LSG. Our findings suggest that weight loss in patients after LSG might be associated with an improvement of constipation symptoms of individual patients.

Vertical Sleeve Gastrectomy Has Better Weight Evolution and Serum Concentrations of Vitamin D when Compared with Roux-Y Gastric Bypass

OBJECTIVE

The objective of this study is to compare the weight evolution and serum concentrations of vitamin D in individuals undergoing Roux-en-Y Gastric Bypass (RYGB) and Sleeve after 1 follow-up year.

METHODOLOGY

Descriptive, prospective, and longitudinal study, with 108 individuals divided into 2 groups: RYGB (55 patients) and Sleeve (53), evaluated preoperatively, and at 6 and 12 postoperatively months. Anthropometric data, serum concentrations of 25(OH)D, calcium, and parathyroid hormone were analyzed.

RESULTS

The Sleeve group showed greater reductions in excess weight and excess body mass index (BMI) when compared with the RYGB group at both times (p < 0.001). Besides, after 12 months, those who had undergone the Sleeve procedure also had higher percentages of surgical success (84.4% versus 65.0%, p = 0.038). The prevalence of preoperative inadequacy of 25(HO)D in both groups was 78.7%. After 6 months, there was an increase in serum concentrations of 25(HO)D in both groups (p < 0.001), but without significant differences between the groups (p = 0.154). In the comparison between 6 and 12 months, there was only a reduction for the RYGB group (p = 0.001). Also, when comparing both groups, the means of vitamin D in patients undergoing RYGB were also lower after 12 months (p = 0.003). There was a negative correlation between vitamin D and parathyroid hormone (r = - 0.235 p = 0.030). The mean serum concentrations of calcium were adequate at all times.

CONCLUSION

Patients undergoing the Sleeve procedure had a better evolution in weight loss and are at a lower risk of vitamin D inadequacy than those undergoing RYGB.

Short-Term Results Suggest That Sleeved Stomach without Resection Is as Effective as Sleeve Gastrectomy in Improving Glucose Control in Type 2 Diabetes Mellitus Sprague-Dawley Rat Model

Background

Although sleeve gastrectomy results in good weight loss and metabolic improvements, it is an irreversible procedure. Therefore, we attempted to assess the possibility of creating a sleeved stomach without resection. Material and Methods. A total of 22 male Sprague-Dawley rats with type 2 diabetes were randomly assigned into 3 different groups: (1) sleeve gastroplasty with gastric remnant-jejunal anastomosis (SGP, n = 8); (2) sleeve gastrectomy (SG, n = 8); and (3) SHAM (n = 6). Body weight, food intake, fasting blood glucose (FBG), hormonal analysis, and oral glucose tolerance test (OGTT) were performed and measured preoperatively and postoperatively.

Results

During the postoperative period, SGP and SG showed significantly lower food intake and body weight when compared with the preoperative levels, respectively (p value < 0.05). Postoperatively, SGP and SG showed improvements in FBG and glucose tolerance levels compared to their respective preoperative levels (p < 0.05). FBG and glucose tolerance levels did not differ between SGP and SG postoperatively. SG resulted in a reduction in fasting ghrelin levels when compared with the preoperative level (p < 0.05). Fasting insulin levels did not differ preoperatively and postoperatively among all groups. Postoperatively, fasting GLP-1 levels were higher in SGP and SG when compared with the preoperative levels, but no statistical significance was observed. Compared preoperatively, the SGP and SG procedures resulted in a decline in HOMA-IR at postoperative 6th week (p < 0.05).

Conclusion

Our animal experiment suggested that at least in the short term, sleeved stomach without resection resulted in similar weight loss and improved glucose control effects compared to sleeve gastrectomy.

Serum Bile Acid Levels Before and After Sleeve Gastrectomy and Their Correlation with Obesity-Related Comorbidities

BACKGROUND AND AIMS

The rising prevalence of morbid obesity is increasing the demand for bariatric surgery. The benefits observed after bariatric surgery seems to be not fully explained by surgery-induced weight loss or traditional cardiovascular risk factors regression or improvement. Some evidences suggest that bile acid (BA) levels change after bariatric surgery, thus suggesting that BA concentrations could influence some of the metabolic improvement induced by bariatric surgery. In this report, we have characterized circulating BA patterns and compared them to metabolic and vascular parameters before and after sleeve gastrectomy (SG).

PATIENTS AND METHODS

Seventy-nine subjects (27 males, 52 females, aged 45 ± 12 years, mean BMI 45 ± 7 kg/m²) SG candidates were included in the study. Before and about 12 months after SG, all subjects underwent a clinical examination, blood tests (including lipid profile, plasma glucose and insulin, both used for calculating HOMA-IR, and glycated hemoglobin), ultrasound visceral fat area estimation, ultrasound flow-mediated dilation evaluation, and determination of plasma BA concentrations.

RESULTS

Before SG, both primary and secondary BA levels were higher in insulin-resistant obese subjects than in non-insulin resistant obese, and BA were positively associated with the markers of insulin-resistance. After SG, total (conjugated and unconjugated) cholic acids significantly decreased (p 0.007), and total lithocholic acids significantly increased (p 0.017). SG-induced total cholic and chenodeoxycholic acid changes were directly associated with surgery-induced glycemia (p 0.011 and 0.033 respectively) and HOMA-IR (p 0.016 and 0.012 respectively) changes.

CONCLUSIONS

Serum BA are associated with glucose metabolism and particularly with markers of insulin-resistance. SG modifies circulating BA pool size and composition. SG-induced BA changes are associated with insulin-resistance amelioration. In conclusion, an interplay between glucose metabolism and circulating BA exists but further studies are needed.

Intestinal barrier function in morbid obesity: results of a prospective study on the effect of sleeve gastrectomy

BACKGROUND

Obesity has been associated with impaired intestinal barrier function. It is not known whether bariatric surgery leads to changes in intestinal barrier function. We hypothesized that obesity is associated with disturbances in gastrointestinal barrier function, and that after bariatric surgery barrier function will improve.

METHODS

Prospective single center study in which we assessed segmental gut permeability by urinary recovery of a multisugar drink in 27 morbidly obese (BMI 43.3 ± 1.1 kg/m²) and 27 age and gender matched lean subjects (BMI 22.9 ± 0.43 kg/m²). Fecal calprotectin, SCFAs, plasma cytokines, and hsCRP were assessed as inflammatory and metabolic markers. Comparisons: (a) morbidly obese subjects vs. controls and (b) 2 and 6 months postsleeve vs. presleeve gastrectomy (n = 14). In another group of 10 morbidly obese and 11 matched lean subjects colonic and ileal biopsies were obtained in order to measure gene transcription of tight junction proteins.

RESULTS

Gastroduodenal permeability (urinary sucrose recovery) was significantly increased in obese vs. lean controls (p < 0.05). Small intestinal and colonic permeability (urinary recovery of lactulose/L-rhamnose and sucralose/erythritol, respectively) in obese subjects were not significantly different from controls. Morbidly obese subjects had a proinflammatory systemic and intestinal profile compared with lean subjects. After sleeve gastrectomy BMI decreased significantly (p < 0.001). Postsleeve gastroduodenal permeability normalized to values that do not differ from lean controls.

CONCLUSIONS

Gastroduodenal permeability, but not small intestinal or colonic permeability, is significantly increased in morbidly obese patients. After sleeve gastrectomy, gastroduodenal permeability normalized to values in the range of lean controls. Thus, the proximal gastrointestinal barrier is compromised in morbid obesity and is associated with a proinflammatory intestinal and systemic profile.

Impact of Laparoscopic Sleeve Gastrectomy on Gastrointestinal Motility

Objective

Laparoscopic sleeve gastrectomy (LSG) was considered mainly as a restrictive procedure due to anatomic alterations in the upper gastrointestinal tract. Additionally, due to neurohormonal alterations, LSG modifies the gastrointestinal motility, which controls appetite and feeling of satiety.

Aim

The aim of the study was to review the impact of laparoscopic sleeve gastrectomy on gastrointestinal motility.

Material and Methods

A search of the medical literature was undertaken in Pubmed, Web of Science, and Cochrane library. Esophageal, gastric, bowel motility were assessed separately.

Results

Nine studies assessed esophageal motility. The data remain debatable attributing to the heterogeneity of follow-up timing, surgical technique, bougie size, and distance from pylorus. The stomach motility was assessed in eighteen studies. Functionally, the sleeve was divided into a passive sleeve and an accelerated antrum. All scintigraphic studies revealed accelerated gastric emptying after LSG except of one. Patients demonstrated a rapid gastroduodenal transit time. The resection of the gastric pacemaker had as a consequence aberrant distal ectopic pacemaking or bioelectrical quiescence after LSG. The bowel motility was the least studied. Small bowel transit time was reduced; opposite to that the initiation of cecal filling and the ileocecal valve transit was delayed.

Conclusion

Laparoscopic sleeve gastrectomy has impacts on gastrointestinal motility. The data remain debatable for esophageal motility. Stomach and small bowel motility were accelerated, while the initiation of cecal filling and the ileocecal valve transit was delayed. Further pathophysiological studies are needed to evaluate the correlation of motility data with clinical symptoms.

Acceleration of small bowel motility after oral administration of dai-kenchu-to (TJ-100) assessed by cine magnetic resonance imaging

Dai-kenchu-to (TJ-100) is an herbal medicine used to shorten the duration of intestinal transit by accelerating intestinal movement. However, intestinal movement in itself has not been evaluated in healthy volunteers using radiography, fluoroscopy, and radioisotopes because of exposure to ionizing radiation. The purpose of this study was to evaluate the effect of TJ-100 on intestinal motility using cinematic magnetic resonance imaging (cine MRI) with a steady-state free precession sequence. Ten healthy male volunteers received 5 g of either TJ-100 or lactose without disclosure of the identity of the substance. Each volunteer underwent two MRI examinations after taking the substances (TJ-100 and lactose) on separate days. They drank 1200 mL of tap water and underwent cine MRI after 10 min. A steady-state free precession sequence was used for imaging, which was performed thrice at 0, 10, 20, 30, 40, and 50 min. The bowel contraction frequency and distention score were assessed. Wilcoxon signed-rank test was used, and differences were considered significant at a P-value <0.05. The bowel contraction frequency tended to be greater in the TJ-100 group and was significantly different in the ileum at 20 (TJ-100, 8.95 ± 2.88; lactose, 4.80 ± 2.92; P < 0.05) and 50 min (TJ-100, 9.45 ± 4.49; lactose, 4.45 ± 2.65; P < 0.05) between the groups. No significant differences were observed in the bowel distention scores. Cine MRI demonstrated that TJ-100 activated intestinal motility without dependence on ileum distention.

Mechanisms of surgical control of type 2 diabetes: GLP-1 is key factor

GLP-1 secretion in response to meals is dramatically increased after gastric bypass operations. GLP-1 is a powerful insulinotropic and anorectic hormone, and analogs of GLP-1 are widely used for the treatment of diabetes and recently approved also for obesity treatment. It is, therefore, reasonable to assume that the exaggerated GLP-1 secretion contributes to the antidiabetic and anorectic effects of gastric bypass. Indeed, human experiments with the GLP-1 receptor antagonist, Exendin 9-39, have shown that the improved insulin secretion, which is responsible for part of the antidiabetic effect of the operation, is reduced and or abolished after GLP-1 receptor blockade. Also the postoperative improvement of glucose tolerance is eliminated and or reduced by the antagonist, pointing to a key role for the exaggerated GLP-1 secretion. Indeed, there is evidence that the exaggerated GLP-1 secretion is also responsible for postprandial hypoglycemia sometimes observed after bypass. Other operations (biliopancreatic-diversion and or sleeve gastrectomy) appear to involve different and/or additional mechanisms, and so does experimental bariatric surgery in rodents. However, unlike bypass surgery in humans, the rodent operations are generally associated with increased energy metabolism pointing to an entirely different mechanism of action in the animals.

Magnetic resonance imaging biomarkers of gastrointestinal motor function and fluid distribution

Magnetic resonance imaging (MRI) is a well established technique that has revolutionized diagnostic radiology. Until recently, the impact that MRI has had in the assessment of gastrointestinal motor function and bowel fluid distribution in health and in disease has been more limited, despite the novel insights that MRI can provide along the entire gastrointestinal tract. MRI biomarkers include intestinal motility indices, small bowel water content and whole gut transit time. The present review discusses new developments and applications of MRI in the upper gastrointestinal tract, the small bowel and the colon reported in the literature in the last 5 years.

Laparoscopic sleeve gastrectomy: More than a restrictive bariatric surgery procedure?

Sleeve gastrectomy (SG) is a restrictive bariatric surgery technique that was first used as part of restrictive horizontal gastrectomy in the original Scopinaro type biliopancreatic diversion. Its good results as a single technique have led to a rise in its use, and it is currently the second most performed technique worldwide. SG achieves clearly better results than other restrictive techniques and is comparable in some aspects to the Roux-en-Y gastric bypass, the current gold standard in bariatric surgery. These benefits have been associated with different pathophysiologic mechanisms unrelated to weight loss such as increased gastric emptying and intestinal transit, and activation of hormonal mechanisms such as increased GLP-1 hormone and decreased ghrelin. The aim of this review was to highlight the salient aspects of SG regarding its historical evolution, pathophysiologic mechanisms, main results, clinical applications and perioperative complications.

GLP-1: a mediator of the beneficial metabolic effects of bariatric surgery?

There has been increasing interest in the role that gut hormones may play in contributing to the physiological changes produced by certain bariatric procedures, such as Roux-en-Y gastric bypass and sleeve gastrectomy. Here, we review the evidence implicating one such gut hormone, glucagon-like peptide-1, as a mediator of the metabolic benefits of these two procedures.

Association between postprandial symptoms and gastric emptying after sleeve gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is an effective bariatric procedure. However, postprandial symptoms can compromise its beneficial effect. It is not known if a changed gastric emptying and these symptoms are related. This study aimed to assess the association between postprandial symptoms and the gastric emptying pattern after LSG.

METHODS

A gastric emptying study with a solid and liquid meal component was performed in the second year after LSG. Before the test, symptoms were assessed using a standardized questionnaire, and during the test, symptoms were scored on a visual analog scale (VAS). Gastric emptying results were expressed as lag phase, half time of gastric emptying (T½), and caloric emptying rate/minute.

RESULTS

Twenty patients (14 F/6 M; age 45.6 ± 7.7 years, weight 93.4 ± 28.2 kg, BMI 31.6 ± 8.1 kg/m(2)) participated in this study; 13 had a low symptom score (≤9, group I), 7 a high symptom score (≥18, group II). VAS scores for epigastric pain, nausea, and belching were significantly higher in group II. Lag phase (solid) was 6.4 ± 4.5 min in group I, 7.3 ± 6.3 in group II (p = 0.94); T½ (solid) was 40.6 ± 10.0 min in group I, 34.4 ± 9.3 in group II (p = 0.27); caloric emptying rate was 3.9 ± 0.6 kcal/min in group I, 3.9 ± 1.0 kcal/min in group II (p = 0.32).

CONCLUSIONS

Patients with postprandial symptoms after LSG reported more symptoms during the gastric emptying study than patients without symptoms. However, there was no difference between gastric emptying characteristics between both groups, suggesting that abnormal gastric emptying is not a major determinant of postprandial symptoms after LSG.

Potential mechanisms mediating improved glycemic control after bariatric/metabolic surgery

Conservative medical treatment for morbid obesity generally fails to sustain weight loss. On the other hand, surgical operations, so-called bariatric surgery, have evolved due to their long-term effects. The global increase in the overweight population and the introduction of laparoscopic surgery have resulted in the use of bariatric surgery spreading quickly worldwide in recent years. Recent clinical evidence suggests that bariatric surgery not only reduces body weight, but also improves secondary serious diseases, including type 2 diabetes mellitus, in so-called metabolic surgery. Moreover, several potential mechanisms mediating the improvement in glycemic control after bariatric/metabolic surgery have been proposed based on the animal and human studies. These mechanisms include changes in the levels of gastrointestinal hormones, bacterial flora, bile acids, intestinal gluconeogenesis and gastrointestinal motility as well as adipose tissue and inflammatory mediators after surgery. The mechanisms underlying improved glycemic control are expected to accelerate the promotion of both metabolic and bariatric surgery. This article describes the current status of bariatric surgery worldwide and in Japan, reviews the accumulated data for weight loss and diabetic improvements after surgery and discusses the potential mechanisms mediating improved glycemic control.

Multiple Factors Related to the Secretion of Glucagon-Like Peptide-1

The glucagon-like peptide-1 is secreted by intestinal L cells in response to nutrient ingestion. It regulates the secretion and sensitivity of insulin while suppressing glucagon secretion and decreasing postprandial glucose levels. It also improves beta-cell proliferation and prevents beta-cell apoptosis induced by cytotoxic agents. Additionally, glucagon-like peptide-1 delays gastric emptying and suppresses appetite. The impaired secretion of glucagon-like peptide-1 has negative influence on diabetes, hyperlipidemia, and insulin resistance related diseases. Thus, glucagon-like peptide-1-based therapies (glucagon-like peptide-1 receptor agonists and dipeptidyl peptidase-4 inhibitors) are now well accepted in the management of type 2 diabetes. The levels of glucagon-like peptide-1 are influenced by multiple factors including a variety of nutrients. The component of a meal acts as potent stimulants of glucagon-like peptide-1 secretion. The levels of its secretion change with the intake of different nutrients. Some drugs also have influence on GLP-1 secretion. Bariatric surgery may improve metabolism through the action on GLP-1 levels. In recent years, there has been a great interest in developing effective methods to regulate glucagon-like peptide-1 secretion. This review summarizes the literature on glucagon-like peptide-1 and related factors affecting its levels.

Enteroendocrine secretion of gut hormones in diabetes, obesity and after bariatric surgery

Gastric bypass surgery is associated with a major weight loss and often causes remission in patients with type 2 diabetes. Surgery is also associated with dramatic increases in the secretion of the gut hormones, glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), both of which regulate appetite and food intake, while GLP-1 in addition functions as an incretin hormone, stimulating insulin secretion. It has been possible to probe the role of GLP-1 for the diabetes resolution after gastric bypass using a GLP-1 receptor antagonist, and it is clear that the enhanced beta cell sensitivity to glucose which underlies the enhanced insulin secretion in the patients after the operation depends critically on the increased GLP-1 secretion. Both hormones seem to contribute importantly to the reduction in food intake after bypass and, therefore, to the weight loss. Currently, there are no data to indicate that decreased secretion of the hormones is involved in the pathogenesis of obesity and/or diabetes, but impaired secretion generally observed in obesity (and hence also in diabetes) may contribute to the development. Because of these effects receptor agonists for both hormones are currently being developed for the treatment of obesity and diabetes.