Detailed characterization of incretin cell distribution along the human small intestine

Expression of the GCG gene and secretion of active glucagon-like peptide-1 varies along the length of intestinal tract in horses

BACKGROUND

Active glucagon-like peptide-1 (aGLP-1) has been implicated in the pathogenesis of equine insulin dysregulation (ID), but its role is unclear. Cleavage of proglucagon (coded by the GCG gene) produces aGLP-1 in enteral L cells.

OBJECTIVES

The aim in vivo was to examine the sequence of the exons of GCG in horses with and without ID, where aGLP-1 was higher in the group with ID. The aims in vitro were to identify and quantify the expression of GCG in the equine intestine (as a marker of L cells) and determine intestinal secretion of aGLP-1.

STUDY DESIGN

Genomic studies were case-control studies. Expression and secretion studies in vitro were cross-sectional.

METHODS

The GCG gene sequence of the exons was determined using a hybridisation capture protocol. Expression and quantification of GCG in samples of stomach duodenum, jejunum, ileum, caecum and ascending and descending colon was achieved with droplet digital PCR. For secretory studies tissue explants were incubated with 12 mM glucose and aGLP-1 secretion was measured with an ELISA.

RESULTS

Although the median [IQR] post-prandial aGLP-1 concentrations were higher (p = 0.03) in animals with ID (10.2 [8.79-15.5]), compared with healthy animals (8.47 [6.12-11.7]), there was 100% pairwise identity of the exons of the GCG sequence for the cohort. The mRNA concentrations of GCG and secretion of aGLP-1 differed (p < 0.001) throughout the intestine.

MAIN LIMITATIONS

Only the exons of the GCG gene were sequenced and breeds were not compared. The horses used for the study in vitro were not assessed for ID and different horses were used for the small, and large, intestinal studies.

CONCLUSIONS

Differences in post-prandial aGLP-1 concentration were not due to a variant in the exons of the GCG gene sequence in this cohort. Both the large and small intestine are sites of GLP-1 secretion.

The Sleeve Gastrectomy with Jejunal Bypass (Original Technique)

Introduction: Sleeve gastrectomy with jejunal bypass (SGJB) has been used as a bariatric/metabolic procedure since 2003, in the search for a simpler than other standard techniques and as effective as them. The jejunal-ileal anastomosis can deliver food directly to the hindgut where incretins are secreted. This procedure has gained popularity around the globe and has been studied in rat models as in humans, especially in South America and Asia. In this review, we present the details of the original surgical technique SGJB, summarized all the publications of the procedure, discuss possible advantages and disadvantages, and provide scientific information to look for the real place between bariatric/metabolic procedures. Methods: With 20 years of experience performing the original SGJB, the authors present the details of the procedure. Results: The SGJB consists of a traditional sleeve with the addition of a jejunal bypass. The jejunum is transected 20-30 cm distally to the ligament of Treitz. Then, the biliopancreatic limb is anastomosed to restore transit 250-300 cm distal to the jejunum transection. This way, the ileum gets in contact with partially digested food with the subsequent production of incretins. Conclusion: In this article, we describe the original Alamo technique of SGJB. It is important to clarify the technical details since many publications have presented different lengths of the defunctionalized jejunal limb. Also, the SGJB has been categorized in the "sleeve plus" procedures and its promising outcomes should rapidly position it as an alternative metabolic surgery.

Individuals with type 2 diabetes have higher density of small intestinal neurotensin-expressing cells

Neurotensin (NT) is a gastro-intestinal hormone involved in several pathways that regulate energy and glucose homeostasis. NT was hypothesized to act in synergy with incretin hormones to potentiate its anti-diabetic effects. Additionally, circulating NT levels were shown to rise after bariatric surgery-induced weight loss. Knowledge of NT-secreting cells distribution along the small intestine and its variation according to diabetes status could provide insights on NT role in mediating type 2 diabetes (T2D) improvement after bariatric surgery. So, our aims were to characterize NT-expressing cell distribution along the human small intestine and to compare the relative density of NT-expressing cells in the small intestine of individuals with and without T2D undergoing bariatric surgery for obesity treatment. Autopsy-derived small intestine fragments (n = 30) were obtained at every 20 cm along the entire intestinal length. Additionally, jejunum biopsies (n = 29) were obtained during elective gastric bypass interventions from patients with (n = 10) or without T2D (n = 18). NT-expressing cells were identified by immunohistochemistry and quantified via computerized morphometric analysis. NT-expressing cell density increased along the human small intestine. NT-expressing cell density was significantly higher from 200 cm distal to the duodenojejunal flexure onward, as well as in subjects with T2D when compared to those without T2D. NT-expressing cell density increases along the human small gut, and a higher density is found in individuals with T2D. This finding suggests a potential role for NT in the mechanisms of disease and T2D improvement observed after bariatric surgery.

Optimal Small Bowel Limb Lengths of Roux-en-Y Gastric Bypass

PURPOSE OF REVIEW

Gastric bypass and biliopancreatic diversion (BPD) have come full circle, from a loop configuration to a Roux-en-Y and finally back to a loop configuration as one anastomosis gastric bypass and single-anastomosis duodenal switch. Most surgeons performing Roux-en-Y gastric bypass (RYGB) do not measure the common channel (CC) length and most surgeons performing BPD do not measure the biliopancreatic limb length (BPL).

RECENT FINDINGS

The small bowel length in humans is variable from as short as < 400 cm to as long as > 1000 cm. The combination of these two facts means that even if surgeons keep the limb lengths constant, surgeons will get variable limb length due to the variability of small bowel length in patients. Hence, outcomes of weight loss, resolution of medical problems, or developing nutritional deficiencies which are related to limb length are variable. In this article, we evaluate the published literature related to the effect of varying the Roux limb, BPL, CC, and total alimentary limb lengths on the outcomes of RYGB. We have focused on historical and current randomized controlled trials as well as systematic reviews and meta-analysis to outline the current literature and our interpretation of this literature.

The Molecular Determinants of Glucagon-like Peptide Secretion by the Intestinal L cell

The intestinal L cell secretes a diversity of biologically active hormones, most notably the glucagon-like peptides, GLP-1 and GLP-2. The highly successful introduction of GLP-1-based drugs into the clinic for the treatment of patients with type 2 diabetes and obesity, and of a GLP-2 analog for patients with short bowel syndrome, has led to the suggestion that stimulation of the endogenous secretion of these peptides may serve as a novel therapeutic approach in these conditions. Situated in the intestinal epithelium, the L cell demonstrates complex relationships with not only circulating, paracrine, and neural regulators, but also ingested nutrients and other factors in the lumen, most notably the microbiota. The integrated input from these numerous secretagogues results in a variety of temporal patterns in L cell secretion, ranging from minutes to 24 hours. This review combines the findings of traditional, physiological studies with those using newer molecular approaches to describe what is known and what remains to be elucidated after 5 decades of research on the intestinal L cell and its secreted peptides, GLP-1 and GLP-2.

SMALL INTESTINAL L CELL DENSITY IN PATIENTS WITH SEVERE OBESITY AFTER ROUX-EN-Y GASTRIC BYPASS

BACKGROUND:

Enteroendocrine L cells can be found in the entire gastrointestinal tract and their incretins act on glycemic control and metabolic homeostasis. Patients with severe obesity and type 2 diabetes mellitus may have lower density of L cells in the proximal intestine.

AIMS:

This study aimed to analyze the density of L cells in the segments of the small intestine in the late postoperative of Roux-en-Y gastric bypass in diabetic patients with standardization of 60 cm in both loops, alimentary and biliopancreatic.

METHODS:

Immunohistochemistry analysis assays were made from intestinal biopsies in three segments: gastrointestinal anastomosis (GIA= Point A), enteroenteral anastomosis (EEA= Point B= 60 cm distal to the GIA) and 60 cm distal to the enteroenteral anastomosis (Point C).

RESULTS:

A higher density of L cells immunostaining the glucagon-1 peptide was observed in the distal portion (Point C) when compared to the more proximal portions (Points A and B).

CONCLUSIONS:

The concentration of L cells is higher 60 cm distal to enteroenteral anastomosis when comparing to proximal segments and may explain the difference in intestinal lumen sensitization and enterohormonal response after Roux-en-Y gastric bypass.

IMMUNOHISTOCHEMICAL DETECTION OF L CELLS IN GASTROINTESTINAL TRACT MUCOSA OF PATIENTS AFTER SURGICAL TREATMENT FOR CONTROL OF TYPE 2 DIABETES MELLITUS

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is a disease of global impact that has led to an increase in comorbidities and mortality in several countries. Immunoexpression of the incretin hormones such as glucagon-like peptide-1 (GLP-1) and peptide YY (3-36) (PYY3-36) can be used as a scorer in the gastrointestinal tract to analyze L-cell activity in response to T2DM treatment. This study aimed to investigate the presence, location, and secretion of L cells in the small intestine of patients undergoing the form of bariatric surgery denominated adaptive gastroenteromentectomy with partial bipartition.

METHODS

Immunohistochemical assays, quantitative real-time polymerase chain reaction (qPCR), and Western blot analysis were performed on samples of intestinal mucosa from patients with T2DM in both the preoperative and postoperative periods.

RESULTS

All results were consistent and indicated basal expression and secretion of GLP-1 and PYY3-36 incretins by L cells. A greater density of cells was demonstrated in the most distal portions of the small intestine. No significant difference was found between GLP-1 and PYY3-36 expression levels in the preoperative and postoperative periods because of prolonged fasting during which the samples were collected.

CONCLUSION

The greater number of L cells in activity implies better peptide signaling, response, and functioning of the neuroendocrine system.

The Sensory Mechanisms of Nutrient-Induced GLP-1 Secretion

The enteroendocrine system of the gut regulates energy homeostasis through the release of hormones. Of the gut-derived hormones, GLP-1 is particularly interesting, as analogs of the hormone have proven to be highly effective for the treatment of type 2 diabetes mellitus and obesity. Observations on increased levels of GLP-1 following gastric bypass surgery have enhanced the interest in endogenous hormone secretion and highlighted the potential of endogenous secretion in therapy. The macronutrients and their digestive products stimulate the secretion of GLP-1 through various mechanisms that we have only begun to understand. From findings obtained from different experimental models, we now have strong indications for a role for both Sodium-Glucose Transporter 1 (SGLT1) and the K⁺_ATP channel in carbohydrate-induced GLP-1 secretion. For fat, the free fatty acid receptor FFA1 and the G-protein-coupled receptor GPR119 have been linked to GLP-1 secretion. For proteins, Peptide Transporter 1 (Pept1) and the Calcium-Sensing Receptor (CaSR) are thought to mediate the secretion. However, attempts at clinical application of these mechanisms have been unsuccessful, and more work is needed before we fully understand the mechanisms of nutrient-induced GLP-1 secretion.

Long-Term Results of One Anastomosis Gastric Bypass: a Single Center Experience with a Minimum Follow-Up of 10 Years

PURPOSE

The purpose of this study was to evaluate the efficacy and safety of the OAGB at least 10 years after surgery.

MATERIAL AND METHODS

We retrospectively reviewed our prospectively collected data on consecutive morbid patients with obesity receiving OAGB from January 2005 to December 2007.

RESULTS

A total of 385 patients met the inclusion criteria. The mean follow-up was 149 months. Of all patients, 52% underwent OAGB as a primary procedure and 48% as a revisional procedure. At the 10-year follow-up, the mean body mass index (BMI) was 30.7 ± 11.8, the mean %TWL was 33.4 ± 10.6, and the mean %EWL was 64.1 ± 24.6. We did not find a significant statistical difference in terms of weight loss between primary OAGB and secondary OAGB. In total, 43% of patients achieved a %EWL greater than 75%, while 29% of the patients had an EWL% that was below 50%. All of the comorbidities related to obesity showed a high improvement or fully resolved. Early complications occurred in 9 patients (2.3%), while the overall rate of late complications was 17.1%. Nineteen patients (4.9%) developed an ulcer at the gastrojejunal anastomosis level, nine patients (2.3%) were re-hospitalized for major malnutrition, thirty-eight patients (9.8%) showed a postoperative biliary reflux, and five patients (2.7%) experienced severe anemia, which required several hospitalizations for iron I.V. supplementation.

CONCLUSION

According to results of the present study, we believe that OAGB has shown to be a technique with a reasonable balance between long-term efficacy and undesirable sequelae.

Electronic Bypass for Diabetes: Optimization of Stimulation Parameters and Mechanisms of Glucagon-Like Peptide-1

OBJECTIVES

Intestinal electrical stimulation (IES) has been proposed for treating diabetes; however, its parameters need to be further systematically optimized. This study aimed to optimize the parameters of IES and investigate its possible mechanisms involving glucagon-like peptide-1 (GLP-1) in diabetic rats.

MATERIALS AND METHODS

Thirty-six high-fat diet-induced diabetic rats were chronically implanted with a pair of bipolar electrodes at the duodenum for IES. The oral glucose tolerance test (OGTT) was performed in a number of sessions with IES using different parameters and biphasic charge-balanced waveforms to derive the best values for train on-time, pulse frequency, and pulse width. Incretin hormones such as GLP-1 were assessed and the GLP-1 antagonist Exendin 9-39 was used to assess the role of GLP-1 in the ameliorating effect of IES on hyperglycemia.

RESULTS

The most effective IES parameters in reducing blood glucose (BG) during the OGTT were derived: 1.2 sec on, 0.3 sec off, 80 Hz, 3 msec. IES with these parameters reduced BG level by at least 29% from 15 min to 180 min (p < 0.05 for all points, N = 10). IES with these stimulation parameters increased plasma GLP-1 level at 30 min, 60 min, 90 min and gastric inhibitory peptide (GIP) level at 30 min (N = 8). Exendin 9-39 blocked the inhibitory effect of IES on BG (p > 0.05, IES + Exendin 9-39 vs. sham-IES, N = 8).

CONCLUSION

IES with the most effective parameters derived in this study improves hyperglycemia in diabetic rats. The ameliorating effect of IES on hyperglycemia is attributed to the enhanced release of GLP-1. IES has great potential for treating diabetes.

From Entero-Endocrine Cell Biology to Surgical Interventional Therapies for Type 2 Diabetes

The physiological roles of the enteroendocrine system in relation to energy and glucose homeostasis regulation have been extensively studied in the past few decades. Considerable advances were made that enabled to disclose the potential use of gastro-intestinal (GI) hormones to target obesity and type 2 diabetes (T2D). The recognition of the clinical relevance of these discoveries has led the pharmaceutical industry to design several hormone analogues to either to mitigate physiological defects or target pharmacologically T2D.Amongst several advances, a major breakthrough in the field was the unexpected observation that enteroendocrine system modulation to T2D target could be achieved by surgically induced anatomical rearrangement of the GI tract. These findings resulted from the widespread use of bariatric surgery procedures for obesity treatment, which despite initially devised to induce weight loss by limiting the systemic availably of nutrients, are now well recognized to influence GI hormone dynamics in a manner that is highly dependent on the type of anatomical rearrangement produced.This chapter will focus on enteroendocrine system related mechanisms leading to improved glycemic control in T2D after bariatric surgery interventions.

Role of Gastrointestinal Hormones as a Predictive Factor for Long-Term Diabetes Remission: Randomized Trial Comparing Metabolic Gastric Bypass, Sleeve Gastrectomy, and Greater Curvature Plication

PURPOSE

Long-term studies comparing the mechanisms of different bariatric techniques for T2DM remission are scarce. We aimed to compare type 2 diabetes (T2DM) remission after a gastric bypass with a 200-cm biliopancreatic limb (mRYGB), sleeve gastrectomy (SG), and greater curvature plication (GCP), and to assess if the initial secretion of gastrointestinal hormones may predict metabolic outcomes at 5 years.

MATERIAL AND METHODS

Forty-five patients with mean BMI of 39.4(1.9)kg/m² and T2DM with HbA_1c of 7.7(1.9)% were randomized to mRYGB, SG, or GCP. Anthropometric and biochemical parameters, fasting concentrations of PYY, ghrelin, glucagon, and AUC of GLP-1 after SMT were determined prior to and at months 1 and 12 after surgery. At 5-year follow-up, anthropometrical and biochemical parameters were determined.

RESULTS

Total weight loss percentage (TWL%) at year 1 and GLP-1 AUC at months 1 and 12 were higher in the mRYGB than in the SG and GCP. TWL% remained greater at 5 years in mRYGB group - 27.32 (7.8) vs. SG - 18.00 (10.6) and GCP - 14.83 (7.8), p = 0.001. At 5 years, complete T2DM remission was observed in 46.7% after mRYGB vs. 20.0% after SG and 6.6% after GCP, p < 0.001. In the multivariate analysis, shorter T2DM duration (OR 0.186), p = 0.008, and the GLP-1 AUC at 1 month (OR 7.229), p = 0.023, were prognostic factors for complete T2DM remission at 5-year follow-up.

CONCLUSIONS

Long-term T2DM remission is mostly achieved with hypoabsortive techniques such as mRYGB. Increased secretion of GLP-1 after surgery and shorter disease duration were the main predictors of T2DM remission at 5 years.

What Is an L-Cell and How Do We Study the Secretory Mechanisms of the L-Cell?

Synthetic glucagon-like peptide-1 (GLP-1) analogues are effective anti-obesity and anti-diabetes drugs. The beneficial actions of GLP-1 go far beyond insulin secretion and appetite, and include cardiovascular benefits and possibly also beneficial effects in neurodegenerative diseases. Considerable reserves of GLP-1 are stored in intestinal endocrine cells that potentially might be mobilized by pharmacological means to improve the body's metabolic state. In recognition of this, the interest in understanding basic L-cell physiology and the mechanisms controlling GLP-1 secretion, has increased considerably. With a view to home in on what an L-cell is, we here present an overview of available data on L-cell development, L-cell peptide expression profiles, peptide production and secretory patterns of L-cells from different parts of the gut. We conclude that L-cells differ markedly depending on their anatomical location, and that the traditional definition of L-cells as a homogeneous population of cells that only produce GLP-1, GLP-2, glicentin and oxyntomodulin is no longer tenable. We suggest to sub-classify L-cells based on their differential peptide contents as well as their differential expression of nutrient sensors, which ultimately determine the secretory responses to different stimuli. A second purpose of this review is to describe and discuss the most frequently used experimental models for functional L-cell studies, highlighting their benefits and limitations. We conclude that no experimental model is perfect and that a comprehensive understanding must be built on results from a combination of models.

L-Cell Expression of Melanocortin-4-Receptor Is Marginal in Most of the Small Intestine in Mice and Humans and Direct Stimulation of Small Intestinal Melanocortin-4-Receptors in Mice and Rats Does Not Affect GLP-1 Secretion

The molecular sensors underlying nutrient-stimulated GLP-1 secretion are currently being investigated. Peripheral administration of melanocortin-4 receptor (MC4R) agonists have been reported to increase GLP-1 plasma concentrations in mice and humans but it is unknown whether this effect results from a direct effect on the GLP-1 secreting L-cells in the intestine, from other effects in the intestine or from extra-intestinal effects. We investigated L-cell expression of MC4R in mouse and human L-cells by reanalyzing publicly available RNA sequencing databases (mouse and human) and by RT-qPCR (mouse), and assessed whether administration of MC4R agonists to a physiologically relevant gut model, isolated perfused mouse and rat small intestine, would stimulate GLP-1 secretion or potentiate glucose-stimulated secretion. L-cell MC4R expression was low in mouse duodenum and hardly detectable in the ileum and MC4R expression was hardly detectable in human L-cells. In isolated perfused mouse and rat intestine, neither intra-luminal nor intra-arterial administration of NDP-alpha-MSH, a potent MC4R agonist, had any effect on GLP-1 secretion (P ≥0.98, n = 5-6) from the upper or lower-half of the small intestine in mice or in the lower half in rats. Furthermore, HS014-an often used MC4R antagonist, which we found to be a partial agonist-did not affect the glucose-induced GLP-1 response in the rat, P = 0.62, n = 6). Studies on transfected COS7-cells confirmed bioactivity of the used compounds and that concentrations employed were well within in the effective range. Our combined data therefore suggest that MC4R-activated GLP-1 secretion in rodents either exclusively occurs in the colon or involves extra-intestinal signaling.

Histologic and microbiological findings of the defunctionalized loop in sleeve gastrectomy with jejunal bypass

BACKGROUND

Bariatric surgery produces anatomic changes in the digestive tract that can affect the intestinal microbiome and, in some cases, can cause small intestinal bacterial overgrowth. Since the inception of the sleeve gastrectomy with jejunal bypass (SGJB) in 2004, there has been discussion regarding the possible development of those complications associated with the now abandoned jejunoileal bypass (JIB) procedure.

OBJECTIVES

The primary endpoint was to characterize the bacteriologic and histopathologic findings in the defunctionalized jejunal loop after the SGJB procedure and to analyze the liver profile. The secondary endpoint was to report SGJB conversions or reversions and to review the differences between SGJB and JIB.

SETTING

Academic medical center.

METHODS

We conducted a prospective study of patients who underwent laparoscopy for any reason, having previously had an SGJB. A 5-cm segment at the proximal end of the excluded limb was resected. Luminal liquid and tissue samples were taken from this segment for aerobic and anaerobic cultures, and pathologic examination of the bowel wall was performed to evaluate trophism and signs of chronic inflammation. Other variables were liver function and pre- and postoperative status. Finally, we retrospectively reviewed the causes of revisional surgery in the prospective database.

RESULTS

Eleven patients underwent laparoscopy. The median time after SGJB was 14 months (range, 10-144 months). There were no complications from the procedure. Eight (72.7%) of the procedures were cholecystectomies. None of the patients showed histologic alterations or signs of chronic infection. The liquid and tissue cultures were negative. The liver tests and the laparoscopic morphology of the liver were normal in all patients, except in 1 with previously documented liver cirrhosis. The number of SGJB revisions was 19 of 1074 (1.8 %), and all of them were converted to Roux-en-Y gastric bypass for severe gastroesophageal reflux.

CONCLUSIONS

In this study, we were unable to demonstrate the presence of symptoms or histologic alterations that would suggest that patients undergoing SGJB develop small intestinal bacterial overgrowth in the short- and medium-term follow-up, unlike those who have undergone JIB. The study constitutes an initial step toward establishing what happens to the defunctionalized jejunal limb as a result of this surgical technique.

Metabolic Outcomes of Surgery for Non-Obese Type 2 Diabetes

The most plausible contributing factor to non-obese type 2 diabetes may be imbalanced incretin release from the intestinal epithelium in response to nutrients. Rerouting intestinal continuity through bypass surgery to modulate incretin release is therefore a reasonable treatment. We believe that a major determinant of metabolic outcomes is entire duodenal exclusion without leaving any duodenal epithelium and exclusion of sufficient length of jejunum. More importantly, the procedure should be implemented with safety and without sequelae. To achieve this, we invented a novel procedure with acceptable surgical safety and excellent and durable metabolic outcomes. Post-surgical intestinal adaptation should be considered to achieve successful outcomes.

Does Reconstruction Type After Gastric Resection Matters for Type 2 Diabetes Improvement?

BACKGROUND

Gastrointestinal (GI) surgery involving gastric resection and bypass of intestinal segments was reported to facilitate glucose control in obese patients with type 2 diabetes (T2D).

AIM

Our aim was to assess whether the type of post-gastrectomy GI reconstruction also influences glucose control in T2D patients with BMI below 35 kg/m² submitted to gastrointestinal surgery without bariatric intention.

METHODS

A cohort of T2D Caucasian patients (n = 40) with upper GI malignancy (n = 33) or complicated reflux disease (n = 7) were submitted to either a gastrectomy plus Billroth II (BII) gastrojejunal anastomosis (n = 17), a gastrectomy plus Roux-en-Y gastrojejunostomy (RY) reconstruction (n = 18; subtotal gastrectomy n = 7 and total gastrectomy n = 11), or atypical gastrectomy without reconstruction (no-R) (n = 5). Patients were evaluated before and 2 years after surgery for body weight, Hb1Ac, need of glucose lowering drugs, and presence of diabetes.

RESULTS

Body mass index (BMI) decreased after every surgical procedure when compared to baseline (- 0.9 ± 0.8 kg/m² for BII vs - 4.3 ± 2.6 kg/m² for RY vs - 4.6 ± 2.5 kg/m² for no-R, p < 0.05), which was only significantly different after RY surgeries. Diabetes remission occurred in 5.9% of BII patients, in 27.8% of RY patients, and 0% of no-R patients, while in patients with persistent T2D, the needs for glucose-lowering drugs were significantly also decreased after RY (31.3% BII vs 66.7% RY vs 25% no-R, p = 0.03).

CONCLUSIONS

T2D Caucasian patients undergoing post-gastrectomy GI reconstructions without a bariatric intention experience a significant improvement of T2D, in a magnitude that could be influenced by the technical procedure performed in favor of RY reconstruction. Thus, presence of T2D should be taken into consideration when deciding for the type of post-gastrectomy GI reconstruction.

A Prospective Single-Arm Trial of Modified Long Biliopancreatic and Short Alimentary Limbs Roux-En-Y Gastric Bypass in Type 2 Diabetes Patients with Mild Obesity

BACKGROUND

Type-2 diabetes (T2D) patients with body mass index (BMI) below 35 kg/m² carry lower remission rates than severely obese T2D individuals submitted to "standard limb lengths" Roux-en-Y gastric bypass (RYGB). Mild-obese patients appear to have more severe forms of T2D, where the mechanisms of glycemic control after a standard-RYGB may be insufficient. The elongation of the biliopancreatic limb may lead to greater stimulation of the distal intestine, alterations in bile acids and intestinal microbiota, among other mechanisms, leading to better metabolic outcomes. The aim of this study is to evaluate the safety and efficacy of the RYGB with a biliopancreatic limb of 200 cm in the control of T2D in patients with BMI 30-35 kg/m².

METHODS

From January 2011 to May 2015, 102 T2D patients with BMI from 30 to 34.9 kg/m² underwent laparoscopic RYGB with the biliopancreatic-limb of 200 cm and the alimentary-limb of 50 cm.

RESULTS

There were no deaths or reoperations. The mean follow-up was 28.1 months. The mean BMI dropped from 32.5 to 25.1 kg/m², while the mean fasting glucose decreased from 182.9 to 89.8 mg/dl and the mean glycated hemoglobin (HbA1c) went from 8.7 to 5.2%. During follow-up, 92.2% had their T2D under complete control (HbA1c < 6%, no anti-diabetic medications), while 7.8% were under partial control. Control of hypertension and dyslipidemia were 89.4 and 85.5%, respectively. No patient developed hypoalbuminemia, and there were mild micronutrient deficiencies.

CONCLUSIONS

RYGB with long-biliopancreatic and short-alimentary limbs is safe and seems effective in achieving complete control of T2D in patients with BMIs between 30 and 35 kg/m².

Predictive Value of Gut Peptides in T2D Remission: Randomized Controlled Trial Comparing Metabolic Gastric Bypass, Sleeve Gastrectomy and Greater Curvature Plication

BACKGROUND

Our aim was to determine the predictive value of gut hormone changes for the improvement of type 2 diabetes (T2D) following metabolic Roux-en-Y gastric bypass (mRYGB), sleeve gastrectomy (SG), and greater curvature plication (GCP) in a randomized controlled trial. Contradictory results have been obtained regarding the role of gastrointestinal hormones (in particular GLP-1) in beneficial metabolic bariatric surgery outcomes.

METHODS

Forty-five patients with T2D (mean BMI 39.4 ± 1.9 kg/m²) were randomly assigned to mRYGB, SG, or GCP. Anthropometric and biochemical parameters, fasting concentrations of PYY, ghrelin, glucagon, and area under the curve (AUC) of GLP-1 after a standard meal test were determined prior to and at months 1 and 12 after surgery.

RESULTS

Twelve months after surgery, total weight loss percentage was higher and HbA1c lower in the mRYGB group than in the SG and GCP groups (-35.2 ± 8.1 and 5.1 ± 0.6% vs. -27.8 ± 5.4 and 6.2 ± 0.8% vs. -20.5 ± 6.8 and 6.6 ± 1.3%; p = 0.007 and p < 0.001, respectively). Moreover, GLP-1 AUC at months 1 and 12 was greater and T2D remission was higher in mRYGB (80 vs. 53.3 vs. 20%, p < 0.001). Insulin treatment (odds ratio (OR) 0.025, p = 0.018) and the increase in GLP-1 AUC from baseline to month 1 (OR 1.021, p = 0.013) were associated with T2D remission.

CONCLUSIONS

mRYGB achieves a superior rate of weight loss and T2D remission at month 12. Enhanced GLP-1 secretion 1 month after surgery was a determinant of glucose metabolism improvement. Registration number ( http://www.clinicaltrials.gov ): NCT14104758.

Enteroendocrine K and L cells in healthy and type 2 diabetic individuals

AIMS/HYPOTHESIS

Enteroendocrine K and L cells are pivotal in regulating appetite and glucose homeostasis. Knowledge of their distribution in humans is sparse and it is unknown whether alterations occur in type 2 diabetes. We aimed to evaluate the distribution of enteroendocrine K and L cells and relevant prohormone-processing enzymes (using immunohistochemical staining), and to evaluate the mRNA expression of the corresponding genes along the entire intestinal tract in individuals with type 2 diabetes and healthy participants.

METHODS

In this cross-sectional study, 12 individuals with type 2 diabetes and 12 age- and BMI-matched healthy individuals underwent upper and lower double-balloon enteroscopy with mucosal biopsy retrieval from approximately every 30 cm of the small intestine and from seven specific anatomical locations in the large intestine.

RESULTS

Significantly different densities for cells positive for chromogranin A (CgA), glucagon-like peptide-1, glucose-dependent insulinotropic polypeptide, peptide YY, prohormone convertase (PC) 1/3 and PC2 were observed along the intestinal tract. The expression of CHGA did not vary along the intestinal tract, but the mRNA expression of GCG, GIP, PYY, PCSK1 and PCSK2 differed along the intestinal tract. Lower counts of CgA-positive and PC1/3-positive cells, respectively, were observed in the small intestine of individuals with type 2 diabetes compared with healthy participants. In individuals with type 2 diabetes compared with healthy participants, the expression of GCG and PYY was greater in the colon, while the expression of GIP and PCSK1 was greater in the small intestine and colon, and the expression of PCSK2 was greater in the small intestine.

CONCLUSIONS/INTERPRETATION

Our findings provide a detailed description of the distribution of enteroendocrine K and L cells and the expression of their products in the human intestinal tract and demonstrate significant differences between individuals with type 2 diabetes and healthy participants.

TRIAL REGISTRATION

NCT03044860.

Immunohistochemical Staining for Uroguanylin, a Satiety Hormone, is Decreased in Intestinal Tissue Specimens From Female Adolescents With Obesity

Gastrointestinal tract-secreted satiety hormones play a significant role in one of the largest health-care challenges for children and adults, obesity. Recent studies in mice identified a novel role for uroguanylin, the endogenous intestinal hormone that binds guanylyl cyclase C (GUCY2C), in regulating satiety via a gut-brain signaling pathway. Mice bred without GUCY2C receptors over-ate and developed obesity. We hypothesized that intestinal uroguanylin expression in pediatric patients with obesity would be lower than patients without obesity, and we attempted to examine the difference with immunohistochemistry. Retrospective chart review of gastrointestinal endoscopic procedures at an academic children's hospital identified patients with normal pathology findings on biopsy. Children aged 8-17 were included in the review; we analyzed biopsy samples from 20 matched pairs that differed only by body mass index (BMI)-for-age (average: 25%-75% vs. high: >95%). Biopsies of the duodenum, terminal ileum, ascending colon, and descending colon were subjected to immunohistochemistry for GUCY2C, uroguanylin, and the endogenous colonic hormone, guanylin. Intensity staining of all specimens was scored by a blinded pathologist. The overall staining intensity for females with high BMI-for-age was less for uroguanylin and guanylin as compared to average BMI-for-age females while GUCY2C staining was equal. Males did not exhibit different staining intensities for uroguanylin or guanylin. More matched female pairs had greater uroguanylin and guanylin staining in the average BMI-for-age cohort. The intestinal expression of uroguanylin, a key satiety hormone, appears to be diminished in female pediatric patients in the setting of obesity.

Should Roux-en-Y gastric bypass biliopancreatic limb length be tailored to achieve improved diabetes outcomes?

The objective is to access the role of Roux-en-Y gastric bypass (RYGB) biliopancreatic limb (BPL) length in type 2 diabetes (T2D) outcomes.RYGB is more effective than medical intervention for T2D treatment in obese patients. Despite the scarcity of available data, previous reports suggest that modifications of the RYGB limb lengths could improve the antidiabetic effects of the surgery.A cohort of obese T2D patients (n = 114) were submitted to laparoscopic RYGB, either with a standard BPL (SBPL) (n = 41; BPL 84 ± 2 cm) or long BPL (LBPL) (n = 73; BPL = 200 cm) and routinely monitored for weight loss and diabetic status up to 5 years after surgery.Baseline clinical features in the 2 patient subgroups were similar. After surgery, there was a significant reduction of body mass index (BMI) in both the groups, although the percentage of excess BMI loss (%EBMIL) after 5 years was higher for LBPL (75.50 ± 2.63 LBPL vs 65.90 ± 3.61 SBPL, P = .04). T2D remission rate was also higher (73% vs 55%, P < .05), while disease relapse rate (13.0% vs 32.5%; P < .05) and antidiabetic drug requirement in patients with persistent diabetes were lower after LBPL. Preoperative T2D duration predicted disease remission, but only for SBPL.RYGB with a longer BPL improves %EBMIL, T2D remission, and glycemic control in those with persistent disease, while it decreases diabetes relapse rate over time. The antidiabetic effects of LBPL RYGB also are less influenced by the preoperative disease duration. These data suggest the RYGB procedure could be tailored to improve T2D outcomes.

A Matched Cohort Analysis of Sleeve Gastrectomy With and Without 300 cm Loop Duodenal Switch With 18-Month Follow-Up

BACKGROUND

In bariatric surgery, a significant question remains unanswered-What proportion of weight loss comes from each component and does this differ with time? Single anastomosis duodenal switch (LDS) combines a vertical sleeve gastrectomy (VSG) with a loop attachment of the duodenal stump. There are two major variables the sleeve, and the intestine that processes ingested food. A comparison of patients that had a VSG with those that have had a LDS approximates the contribution of each component.

METHODS

A retrospective matched cohort analysis of VSG and LDS patients was obtained by matching every LDS patient to a VSG patient of the same sex and BMI. Excess weight lost percentage (%EWL) and the total weight loss percentage (%TWL) was analyzed. The data was compared through descriptive statistics and non-linear regression analysis.

RESULTS

Over 18 months, patients who received the LDS lost more %TWL and %EWL and the difference was statistically significant (p < 0.05). Additionally, with time, the difference became more profound. Weight loss stabilized at approximately 9-12 months and 15 to 18 for VSG and LDS patients', respectively. At 6 months post op, there was approximately 13 % difference in weight loss. This increased to 29 % difference at 18 months.

CONCLUSION

LDS patients lose more weight than VSG. Preserving 3 m of intestinal length adds 30 % greater weight loss at 18 months. Early weight loss is similar between the two operations, while the intestinal component becomes more important with weight loss differentials increasing as time since surgery lengthens.

The Importance of the Gastrointestinal Tract in Controlling Food Intake and Regulating Energy Balance

The gastrointestinal tract, the key interface between ingested nutrients and the body, plays a critical role in regulating energy homeostasis. Gut-derived signals convey information regarding incoming nutrients to the brain, initiating changes in eating behavior and energy expenditure, to maintain energy balance. Here we review hormonal, neural, and nutrient signals emanating from the gastrointestinal tract and evidence for their role in controlling feeding behavior. Mechanistic studies that have utilized pharmacologic and/or transgenic approaches targeting an individual hormone/mediator have yielded somewhat disappointing body weight changes, often leading to the hormone/mediator in question being dismissed as a potential obesity therapy. However, the recent finding of sustained weight reduction in response to systemic administration of a long-acting analog of the gut-hormone glucagon-like peptide-1 highlights the therapeutic potential of gut-derived signals acting via nonphysiologic mechanisms. Thus, we also review therapeutics strategies being utilized or developed to leverage gastrointestinal signals in order to treat obesity.

The incretin system ABCs in obesity and diabetes - novel therapeutic strategies for weight loss and beyond

Incretins are gastrointestinal-derived hormones released in response to a meal playing a key role in the regulation of postprandial secretion of insulin (incretin effect) and glucagon by the pancreas. Both incretins, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 (GLP-1), have several other actions by peripheral and central mechanisms. GLP-1 regulates body weight by inhibiting appetite and delaying gastric, emptying actions that are dependent on central nervous system GLP-1 receptor activation. Several other hormones and gut peptides, including leptin and ghrelin, interact with GLP-1 to modulate appetite. GLP-1 is rapidly degraded by the multifunctional enzyme dipeptidyl peptidase-4 (DPP-4). DPP-4 is involved in adipose tissue inflammation, which is associated with insulin resistance and diabetes progression, being a common pathophysiological mechanism in obesity-related complications. Furthermore, the incretin system appears to provide the basis for understanding the high weight loss efficacy of bariatric surgery, a widely used treatment for obesity, often in association with diabetes. The present review brings together new insights into obesity pathogenesis, integrating GLP-1 and DPP-4 in the complex interplay between obesity and inflammation, namely, in diabetic patients. This in turn will provide the basis for novel incretin-based therapeutic strategies for obesity and diabetes with promising benefits in addition to weight loss. © 2016 World Obesity.