The ileal brake: a fifteen-year progress report

Glucagon-like peptide-1 receptor agonist-based agents and weight loss composition: Filling the gaps

Excess adiposity is at the root of type 2 diabetes (T2D). Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have emerged as first-line treatments for T2D based on significant weight loss results. The composition of weight loss using most diets consists of <25% fat-free mass (FFM) loss, with the remainder from fat stores. Higher amounts of weight loss (achieved with metabolic bariatric surgery) result in greater reductions in FFM. Our aim was to assess the impact that GLP-1RA-based treatments have on FFM. We analysed studies that reported changes in FFM with the following agents: exenatide, liraglutide, semaglutide, and the dual incretin receptor agonist tirzepatide. We performed an analysis of various weight loss interventions to provide a reference for expected changes in FFM. We evaluated studies using dual-energy X-ray absorptiometry (DXA) for measuring FFM (a crude surrogate for skeletal muscle). In evaluating the composition of weight loss, the percentage lost as fat-free mass (%FFML) was equal to ΔFFM/total weight change. The %FFML using GLP-1RA-based agents was between 20% and 40%. In the 28 clinical trials evaluated, the proportion of FFM loss was highly variable, but the majority reported %FFML exceeding 25%. Our review was limited to small substudies and the use of DXA, which does not measure skeletal muscle mass directly. Since FFM contains a variable amount of muscle (approximately 55%), this indirect measure may explain the heterogeneity in the data. Assessing quantity and quality of skeletal muscle using advanced imaging (magnetic resonance imaging) with functional testing will help fill the gaps in our current understanding.

Recent Advances and Therapeutic Benefits of Glucagon-Like Peptide-1 (GLP-1) Agonists in the Management of Type 2 Diabetes and Associated Metabolic Disorders

Glucagon-like peptide-1 (GLP-1) agonists have emerged as a groundbreaking class of medications for managing type 2 diabetes and associated metabolic disorders. These agents not only improve glycemic control by increasing insulin secretion and reducing glucagon levels but also promote significant weight loss, enhance cardiovascular and renal health, and offer potential neuroprotective benefits. Their multifaceted mechanisms include appetite suppression, increased energy expenditure, and direct neuroprotective effects. GLP-1 agonists have shown recent benefits in Obstructive Sleep Apnea, and the treatment of neurodegenerative diseases such as Alzheimer's and Parkinson's, as well as reducing the risk of stroke. This review highlights the therapeutic potential of GLP-1 agonists in diabetes management and beyond, advocating for continued research to optimize their clinical use and explore new therapeutic avenues.

Glucagon-Like Peptide Receptor-1 Agonists Used for Medically-Supervised Weight Loss in Patients With Hip and Knee Osteoarthritis: Critical Considerations for the Arthroplasty Surgeon

Patients with morbid obesity and concomitant hip or knee osteoarthritis represent a challenging patient demographic to treat as these patients often present earlier in life, have more severe symptoms, and have worse surgical outcomes following total hip and total knee arthroplasty. Previously, bariatric and metabolic surgeries represented one of the few weight loss interventions that morbidly obese patients could undergo prior to total joint arthroplasty. However, data regarding the reduction in complications with preoperative bariatric surgery remain mixed. Glucagon-like peptide receptor-1 (GLP-1) agonists have emerged as an effective treatment option for obesity in patients with and without diabetes mellitus. Furthermore, recent data suggest these medications may serve as potential anti-inflammatory and disease-modifying agents for numerous chronic conditions, including osteoarthritis. This review will discuss the GLP-1 agonists and GLP-1/glucose-dependent insulinotropic polypeptide dual agonists currently available, along with GLP-1/glucose-dependent insulinotropic polypeptide/glucagon triple agonists presently being developed to address the obesity epidemic. Furthermore, this review will address the potential problem of GLP-1-related delayed gastric emptying and its impact on the timing of elective total joint arthroplasty. The review aims to provide arthroplasty surgeons with a primer for implementing this class of medication in their current and future practice, including perioperative instructions and perioperative safety considerations when treating patients taking these medications.

Normal Ileal Mucus Is Inadequate for Epithelial Protection in Ileal Pouch Mucosa

BACKGROUND

Clinical, nonspecific pouchitis is common after restorative proctocolectomy for ulcerative colitis, but its cause is unknown. A possible lack of protection for the ileal mucosa in its role as a reservoir for colonic-type bacteria may be the missing piece in defining the causes of pouchitis.

OBJECTIVE

The study aimed to review the causes of pouchitis and introduce the hypothesis that inadequate mucus protection in the pouch, combined with a predisposition to abnormal inflammation, is the most common cause of nonspecific pouchitis.

DATA SOURCES

Review of PubMed and MEDLINE for articles discussing pouchitis and intestinal mucus.

STUDY SELECTION

Studies published from 1960 to 2023. The main search terms were "pouchitis," and "intestinal mucus," whereas Boolean operators were used with multiple other terms to refine the search. Duplicates and case reports were excluded.

MAIN OUTCOME MEASURES

Current theories about the cause of pouchitis, descriptions of the role of mucus in the physiology of intestinal protection, and evidence of the effects of lack of mucus on mucosal inflammation.

RESULTS

The crossreference of "intestinal mucus" with "pouchitis" produced 9 references, none of which discussed the role of mucus in the development of pouchitis. Crossing "intestinal mucus" with "pouch" resulted in 32 articles, combining "pouchitis" with "barrier function" yielded 37 articles, and "pouchitis" with "permeability" yielded only 8 articles. No article discussed the mucus coat as a barrier to bacterial invasion of the epithelium or mentioned inadequate mucus as a factor in pouchitis. However, an ileal pouch produces a colonic environment in the small bowel, and the ileum lacks the mucus protection needed for this sort of environment. This predisposes pouch mucosa to bacterial invasion and chronic microscopic inflammation that may promote clinical pouchitis in patients prone to an autoimmune response.

LIMITATIONS

No prior studies address inadequate mucus protection and the origin of proctitis. There is no objective way of measuring the autoimmune tendency in patients with ulcerative colitis.

CONCLUSIONS

Studies of intestinal mucus in the ileal pouch and its association with pouchitis are warranted.

Fat digestion and absorption: Normal physiology and pathophysiology of malabsorption, including diagnostic testing

Fat digestion and absorption play crucial roles in maintaining energy homeostasis and supporting essential physiological functions. The initial stage of fat digestion occurs in the stomach, where gastric lipase begins the hydrolysis of triglycerides. However, most fat digestion takes place in the small intestine via pancreatic enzymes and bile salts. Emulsification of fat by bile acids facilitates enzymatic action, breaking down triglycerides into free fatty acids and monoglycerides, which are then able to be absorbed by enterocytes. Fat malabsorption can result from various underlying conditions, such as exocrine pancreatic insufficiency, bile acid disorders, or intestinal diseases. The clinical manifestations of fat malabsorption include steatorrhea, malnutrition, and deficiencies of fat-soluble vitamins. Diagnostic approaches involve assessing fecal fat levels, imaging studies, and various functional tests to identify the specific etiology. This review article will describe the normal physiologic process of fat digestion and absorption and discuss various pathophysiology that can lead to fat malabsorption within the gastrointestinal tract as well as their respective diagnostic testing modalities. Effective digestion of fat is essential for overall health, because it allows for absorption of many essential nutrients, plays an integral role in cellular and structural function, and supplies energy to the body. When this is dysfunctional, disorders of malabsorption can occur. This article will give a brief overview of the physiologic process of fat digestion and absorption in healthy individuals as well as review important pathophysiology that can lead to fat malabsorption within the gastrointestinal tract and current diagnostic testing modalities.

Impact of gastric and bowel surgery on gastrointestinal drug delivery

General surgical procedures on the gastrointestinal tract are commonly performed worldwide. Surgical resections of the stomach, small intestine, or large intestine can have a significant impact on the anatomy and physiological environment of the gastrointestinal tract. These physiological changes can affect the effectiveness of orally administered formulations and drug absorption and, therefore, should be considered in rational drug formulation design for specific pathological conditions that are commonly associated with surgical intervention. For optimal drug delivery, it is important to understand how different surgical procedures affect the short-term and long-term functionality of the gastrointestinal tract. The significance of the surgical intervention is dependent on factors such as the specific region of resection, the degree of the resection, the adaptive and absorptive capacity of the remaining tissue, and the nature of the underlying disease. This review will focus on the common pathological conditions affecting the gastric and bowel regions that may require surgical intervention and the physiological impact of the surgery on gastrointestinal drug delivery. The pharmaceutical considerations for conventional and novel oral drug delivery approaches that may be impacted by general surgical procedures of the gastrointestinal tract will also be addressed.

Nutritional Management of Intestinal Failure due to Short Bowel Syndrome in Children

BACKGROUND

The most common cause of intestinal failure (IF) in childhood remains short bowel syndrome (SBS), where bowel mass is significantly reduced due to a congenital atresia or resection and parenteral nutrition (PN) needed. Home PN has improved outcome and quality of life, but the long-term therapeutic goal is to achieve enteral autonomy whilst avoiding long term complications. This paper is aimed at discussing nutritional strategies available to clinicians caring for these patients.

METHODS

A literature search was performed from 1992 to 2022 using Pubmed, MEDLINE and Cochrane Database of Systematic Reviews, and recent guidelines were reviewed. In the absence of evidence, recommendations reflect the authors' expert opinion.

RESULTS

Consensus on the best possible way of feeding children with IF-SBS is lacking and practice varies widely between centres. Feeding should commence as soon as possible following surgery. Oral feeding is the preferred route and breast milk (BM) the first milk of choice in infants. Donor BM, standard preterm or term formula are alternatives in the absence of maternal BM. Extensively hydrolysed or amino acid-based feeds are used when these are not tolerated. Solids should be introduced as soon as clinically appropriate. Children are encouraged to eat by mouth and experience different tastes and textures to avoid oral aversion. Aggressive weaning of PN and tube (over-) feeding are now discouraged.

CONCLUSIONS

To date, uniform agreement on the optimal type of feed, timing of food introduction and feeding regime used is lacking and great difference in practice remains. There is need for more research to establish common treatment protocols.

Gastrin and Nitric Oxide Production in Cultured Gastric Antral Mucosa Are Altered in Response to a Gastric Digest of a Dietary Supplement

In vitro organ culture can provide insight into isolated mucosal responses to particular environmental stimuli. The objective of the present study was to investigate the impact of a prolonged culturing time as well as the addition of acidic gastric fluid into the in vitro environment of cultured gastric antral tissue to evaluate how altering the commonly used neutral environment impacted tissue. Furthermore, we aimed to investigate the impact of G's Formula, a dietary supplement for horses, on the secretion of gastrin, interleukin1-beta (IL-1β), and nitric oxide (NO). These biomarkers are of interest due to their effects on gastric motility and mucosal activity. Gastric mucosal tissue explants from porcine stomachs were cultured in the presence of a simulated gastric fluid (BL, n = 14), simulated gastric fluid containing the dietary supplement G's Formula (DF, n = 12), or an equal volume of phosphate buffered saline (CO, n = 14). At 48 and 60 h, 10⁻⁵ M carbachol was used to stimulate gastrin secretion. Cell viability was assessed at 72 h using calcein and ethidium-homodimer 1 staining. Media was analyzed for gastrin, IL-1β, and NO at 48, 60, and 72 h. There were no effects of treatment or carbachol stimulation on explant cell viability. Carbachol resulted in a significant increase in gastrin concentration in CO and DF treatments, but not in BL. NO was higher in CO than in BL, and NO increased in the CO and DF treatments but not in BL. In conclusion, the addition of carbachol and gastric digests to culture media did not impact cell viability. The use of an acidic gastric digest (BL) reduced the effect of cholinergic stimulation with carbachol at a concentration of 10⁻⁵ M and reduced NO secretion. The addition of the dietary supplement to the gastric digest (DF) appeared to mediate these effects within this model. Further research is required to evaluate the specific effects of this dietary supplement on direct markers of mucosal activity and the functional relevance of these results in vivo.

Formulation strategies to improve the efficacy of intestinal permeation enhancers. Adv Drug Deliv Rev 2021;177:113925. [PMID: 34418495 DOI: 10.1016/j.addr.2021.113925]

The use of chemical permeation enhancers (PEs) is the most widely tested approach to improve oral absorption of low permeability active agents, as represented by peptides. Several hundred PEs increase intestinal permeability in preclinical bioassays, yet few have progressed to clinical testing and, of those, only incremental increases in oral bioavailability (BA) have been observed. Still, average BA values of ~1% were sufficient for two recent FDA approvals of semaglutide and octreotide oral formulations. PEs are typically screened in static in vitro and ex-vivo models where co-presentation of active agent and PE in high concentrations allows the PE to alter barrier integrity with sufficient contact time to promote flux across the intestinal epithelium. The capacity to maintain high concentrations of co-presented agents at the epithelium is not reached by standard oral dosage forms in the upper GI tract in vivo due to dilution, interference from luminal components, fast intestinal transit, and possible absorption of the PE per se. The PE-based formulations that have been assessed in clinical trials in either immediate-release or enteric-coated solid dosage forms produce low and variable oral BA due to these uncontrollable physiological factors. For PEs to appreciably increase intestinal permeability from oral dosage forms in vivo, strategies must facilitate co-presentation of PE and active agent at the epithelium for a sustained period at the required concentrations. Focusing on peptides as examples of a macromolecule class, we review physiological impediments to optimal luminal presentation, discuss the efficacy of current PE-based oral dosage forms, and suggest strategies that might be used to improve them.

A Review of the Extraction and Closed-Loop Spray Drying-Assisted Micro-Encapsulation of Algal Lutein for Functional Food Delivery

In this study, the physical and chemical properties and bioavailability of lutein have been summarized, with the novelty of this work being the review of lutein from production to extraction, through to preservation and drying, in order to deliver a functional food ingredient. The potential health functions of lutein have been introduced in detail. By comparing algae and marigold flowers, the advantages of algae extraction technology have been discussed. In this article, we have introduced the use of closed-loop spray drying technology to microencapsulate lutein to improve its stability and solubility. Microencapsulation of unstable substances by spray drying is a potentially useful direction that is worth exploring further.

Bariatric and Metabolic Therapies Targeting the Small Intestine

The global prevalence of obesity and type 2 diabetes (T2DM) necessitates an increased reliance on effective and safe endoscopic therapies. While surgery is highly effective, endoscopic therapies may be able to reach a greater number of affected individuals and help to reduce the burden of disease worldwide. Although current endoscopic treatments entail space occupying gastric devices as well as suturing or plication, innovative, non-Food and Drug Administration (FDA) approved small bowel specific endoscopic bariatric and metabolic therapies have been developed within the last several years. Small intestine therapies include endoluminal bypass liners, duodenal mucosal resurfacing, endoscopic anastomosis systems, and restricted duodenal flow treatments. These endoscopic bariatric and metabolic therapies rely upon foregut and hindgut mechanisms to achieve weight loss and improve glucose homeostasis. This review will detail these important small bowel mechanisms and evaluates current small bowel endoscopic treatments.

Ileal Transposition in Rats Reduces Energy Intake, Body Weight, and Body Fat Most Efficaciously When Ingesting a High-Protein Diet

Purpose

Ileal transposition (IT) allows exploration of hindgut effects of bariatric procedures in inducing weight loss and reducing adiposity. Here we investigated the role of dietary macronutrient content on IT effects in rats.

Methods

Male Lewis rats consuming one of three isocaloric liquid diets enriched with fat (HF), carbohydrates (HC), or protein (HP) underwent IT or sham surgery. Body weight, energy intake, energy efficiency, body composition, and (meal-induced) changes in plasma GIP, GLP-1, PYY, neurotensin, and insulin levels were measured.

Results

Following IT, HC intake remained highest leading to smallest weight loss among dietary groups. IT in HF rats caused high initial weight loss and profound hypophagia, but the rats caught up later, and finally had the highest body fat content among IT rats. HP diet most efficaciously supported IT-induced reduction in body weight and adiposity, but (as opposed to other diet groups) lean mass was also reduced. Energy efficiency decreased immediately after IT irrespective of diet, but normalized later. Energy intake alone explained variation in post-operative weight change by 80%. GLP-1, neurotensin, and PYY were upregulated by IT, particularly during (0–60 min) and following 17-h post-ingestive intake, with marginal diet effects. Thirty-day post-operative cumulative energy intake was negatively correlated to 17-h post-ingestive PYY levels, explaining 47% of its variation.

Conclusion

Reduction in energy intake underlies IT-induced weight loss, with highest efficacy of the HP diet. PYY, GLP-1, and neurotensin levels are upregulated by IT, of which PYY may be most specifically related to reduced intake and weight loss after IT.

Advances in Oral Drug Delivery for Regional Targeting in the Gastrointestinal Tract - Influence of Physiological, Pathophysiological and Pharmaceutical Factors

The oral route is by far the most common route of drug administration in the gastrointestinal tract and can be used for both systemic drug delivery and for treating local gastrointestinal diseases. It is the most preferred route by patients, due to its advantages, such as ease of use, non-invasiveness, and convenience for self-administration. Formulations can also be designed to enhance drug delivery to specific regions in the upper or lower gastrointestinal tract. Despite the clear advantages offered by the oral route, drug delivery can be challenging as the human gastrointestinal tract is complex and displays a number of physiological barriers that affect drug delivery. Among these challenges are poor drug stability, poor drug solubility, and low drug permeability across the mucosal barriers. Attempts to overcome these issues have focused on improved understanding of the physiology of the gastrointestinal tract in both healthy and diseased states. Innovative pharmaceutical approaches have also been explored to improve regional drug targeting in the gastrointestinal tract, including nanoparticulate formulations. This review will discuss the physiological, pathophysiological, and pharmaceutical considerations influencing drug delivery for the oral route of administration, as well as the conventional and novel drug delivery approaches. The translational challenges and development aspects of novel formulations will also be addressed.

Possible role of peptide YY (PYY) in the pathophysiology of irritable bowel syndrome (IBS)

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder of unknown aetiology for which there is no effective treatment. Although IBS does not increase mortality, it reduces the quality of life and is an economic burden to both the patients themselves and society as a whole. Peptide YY (PYY) is localized in endocrine cells located in the ileum, colon and rectum. The concentration of PYY and the density of PYY cells are decreased in both the colon and rectum but unchanged in the ileum of patients with IBS. The low density of PYY cells in the large intestine may be caused by a decreased number of stem cells and their progeny toward endocrine cells. PYY regulates the intestinal motility, secretion and absorption as well as visceral sensitivity via modulating serotonin release. An abnormality in PYY may therefore contribute to the intestinal dysmotility and visceral hypersensitivity seen in IBS patients. Diet management involving consuming a low-FODMAP diet restores the density of PYY cells in the large intestine and improves abdominal symptoms in patients with IBS. This review shows that diet management appears to be a valuable tool for correcting the PYY abnormalities in the large intestine of IBS patients in the clinic.

Effect of wheat distillers dried grains with solubles and exogenous xylanase on laying hen performance and egg quality

Despite the rapid increase in the use of wheat distillers dried grains with solubles (DDGS) within the poultry sector, little information is available on how the long-term feeding of this by-product will affect the performance of laying hens. This experiment examined the effect of wheat DDGS, with and without exogenous xylanase on dietary apparent metabolizable energy (AME), total tract dry matter retention (DMR), nitrogen retention (NR), fat digestibility (FD) coefficients, feed intake (FI), bodyweight gain (BWG), eggs laid, mean egg weight, egg mass output, and egg quality characteristics including albumin height (AH), Haugh units (HU), yolk color, eggshell strength, and thickness. A total of 320 Hy-Line brown laying hens were randomly allocated to 80 enriched layer colonies (groups of 4). A total of 2 control wheat-soybean meal-based diets were formulated to contain 11.60 MJ/kg. One of the diets contained 300 g/kg wheat DDGS, while the other was DDGS free, with a respective crude protein content of 171.1 g/kg and 166.5 g/kg. Both diets were divided by 2 and half of them were supplemented with 2,500 U/kg of xylanase, resulting in 4 diets in total. Data was analyzed as a 2 × 2 factorial arrangement of treatments with analysis of variance (ANOVA). Diets were fed ad libitum from 17 to 43 wk of age and data was collected from 23 to 43 wk. The inclusion of wheat DDGS reduced (P < 0.001) dry matter retention (DMR), FI, BWG, eggs laid, mean egg weight, and egg mass. However, xylanase supplementation improved AME and NR in diets containing wheat DDGS and FD in diets without DDGS (DDGS × xylanase, P < 0.05) and tended to improve (P < 0.10) BWG and egg mass output. For egg quality measurements, the inclusion of DDGS improved (P = 0.046) HU values, eggshell strength (P < 0.001), and increased (P < 0.001) yolk color intensity. This experiment showed xylanase can be used to improve the AME and NR of DDGS-based diets. However, the long-term feeding of 300 g/kg wheat DDGS negatively impacts the productive performance of hens.

Indications and outcomes of home parenteral nutrition in patients with an ileoanal pouch

INTRODUCTION

Restorative proctocolectomy is a surgical treatment for patients with medically refractory ulcerative colitis and some cases of familial adenomatous polyposis. Intestinal failure, defined as an inability to maintain adequate hydration and micronutrient balances when on a conventionally accepted normal diet, is a rare complication of restorative proctocolectomy. We describe our experience of patients with restorative proctocolectomy who have developed intestinal failure requiring parenteral support.

MATERIAL AND METHODS

This was a retrospective analysis using a database of patients referred to our intestinal failure unit from January 1998 to January 2016. We analysed the records of all those patients who had restorative proctocolectomy who developed intestinal failure.

RESULTS

807 patient records analysed, 35 patients were found to have had a restorative proctocolectomy (13 male and 22 female). Ninety-one percent (n = 32) of patients developed IF as a consequence of unpredictable complications which occurred after RPC formation. Potentially predictable complications were noted in 9% (n = 3) of patients.

DISCUSSION AND CONCLUSIONS

Most cases of intestinal failure in restorative proctocolectomy were unpredictable. In a small number of patients, accurate assessment and measurement of the small intestine may have better predicted the adverse outcome of intestinal failure allowing improved pre-operative counseling of patients.

Pilot Study of a New Model of Bariatric Surgery: Laparoscopic Intestinal Bipartition-Safety and Efficacy Against Metabolic Disorders

BACKGROUND

Despite the availability of many gastric surgery techniques to reduce obesity and its associated comorbidities, most of these procedures can result in life-threatening conditions including lifetime chronic illnesses and death. Vertical sleeve gastrectomy and Roux-en-Y gastric bypass have been reported to improve obesity-related comorbidities such as T2DM, but the long-term efficacy of these two procedures is unknown, and their significant impact on long-term weight loss was diminished by complications as reported in previous studies. Recently, laparoscopic biliopancreatic diversion with duodenal switch (BPD/DS) was developed to achieve sustained weight loss (Buchwald et al. Am J Med. 122:248-56, 2009; Sjöström et al. N Engl J Med. 351:2683-93, 2004) as well as an improvement in comorbid conditions, such as T2DM and hypertension (Buchwald et al. in Am J Med. 122:248-56, 2009; Dorman et al. Surgery. 152:758-65, 2012). The malabsorptive strategy of bypassing portions of the small intestine and delivering nutrients directly to the ileum may promote weight loss by enhanced activation of a negative feedback mechanism known as the "ileal brake" (Näslund et al. J Gastrointest Surg. 5:556-67, 2001). The purpose of this pilot study was to evaluate the safety, reproducibility, and efficiency of a new surgical bariatric model of laparoscopic intestinal bipartition (LIB) in patients with a BMI between 35 and 40 kg/m². The setting was in university hospitals.

METHODS

Between January 2011 and September 2012, seven patients were enrolled in the study and underwent the LIB procedure. One patient was operated by LIB for morbid obesity with comorbidities, especially T2DM, without any previous bariatric or gastric surgery. Six patients underwent the surgery after a sleeve gastrectomy for ≥ 4 years with a recurrence of obesity and diabetes.

RESULTS

The comorbidity factors decreased to the normal values in all patients at 6 months, 1 year, and 5 years postoperatively. The percentage of total weight loss was 21.1% at 6 months, 22.6% at 1 year, and 15.6% at 5 years. Weight excess was significantly lower at 6-month, 1-year, and 5-year postoperatively compared with baseline (p < 0.001). Comparison of comorbidity values at 6 months, 1 year, and 5 years did not show any significant differences.

CONCLUSION

Laparoscopic intestinal bipartition produced a total recovery from obesity-related comorbidities, especially T2DM and EWL without any signs of nutritional deficiency, although the 5-year follow-up is ongoing in order to demonstrate the efficacy and long-term durability of this procedure.

Growth factors and their use in short bowel

PURPOSE OF REVIEW

To examine the most recent literature on the clinical trials associated with the relevant growth factors that have been of interest in the treatment of short bowel.

RECENT FINDINGS

Short bowel is a rare but devastating condition that condemns patients to lifelong parenteral support. Historically, treatment options negating the need for parenteral support were limited. Therapeutic growth factor use is of interest, but the clinical trial data are inconclusive. The STEPS-2 trial was the first trial that showed a sustained positive effect of the growth factor glucagon-like peptide-2 (GLP-2). This led to a phase shift in the management of short bowel, with the US Food and Drug Administration approval of the GLP-2 analogue teduglutide in 2012. This review summarizes all the relevant clinical trials of growth factors in the treatment of short bowel.

SUMMARY

GLP-2 has shown that growth factors can revolutionize the treatment of short bowel. Data however are lacking with regards to the solitary use of other factors. This review highlights the need for further work using the factors in combination as well as considering their use in novel methods for example in the field of regenerative medicine.

The Effect of Lupinus albus on Growth Performance, Body Composition and Satiety Hormones of Male Pigs Immunized against Gonadotrophin Releasing Factor

Two hundred and ninety four pigs were used with the aim to develop a dietary management strategy using Lupinus albus L. (albus lupins) to reduce the increase in feed intake and subsequent increase in carcass fatness in pigs immunized against gonadotrophin releasing factor (immunocastrates; IC males) and entire male pigs in the late finishing stage. From day (d) 0 to 28, IC males fed the control diet grew faster (p = 0.009) than entire males fed the control diet but there was no difference in growth rate between sexes for pigs fed albus lupins for 14 days pre-slaughter (Albus 14) or pigs fed albus lupins for 28 days pre-slaughter (Albus 28). From d 15 to 28, IC males receiving the Albus 14 diet grew more slowly (p < 0.001) than entire males receiving the Albus 14 diet. From d 15 to 28 (p < 0.001), IC males fed the control diet ate more feed than entire males fed the control diet, although there was no difference between sexes in feed intake of the Albus 14 and Albus 28 diet. Immunocastrates had a lower backfat when fed either Albus 14 or Albus 28 compared to the control diet, although there was no difference between diets for entire males. There was also a trend for pigs on the Albus 14 and Albus 28 diets to have a higher lean deposition (p = 0.055) and a lower fat deposition (p = 0.056) compared to the pigs on the control diet. Pigs fed the Albus 28 diet had a lower plasma ghrelin concentration compared to pigs fed the Albus 14 or the control diet (p = 0.002). Pigs fed the Albus 28 diet had a higher peptide YY concentration than those fed the control or albus 14 diet (p = 0.004). The inclusion of albus lupins at 20% in the diets of IC male pigs for either 14 or 28 days pre-slaughter was successful in reducing feed intake, body fat and backfat to similar levels of entire males. However, the growth rate of the IC male pigs was impacted more than would be desirable.

Does the Ileal Brake Contribute to Delayed Gastric Emptying After Pancreatoduodenectomy?

Delayed gastric emptying (DGE) represents a significant cause for morbidity following pancreatoduodenectomy (PD). At a time when no specific and universally effective therapy exists to treat these patients, elucidating other potential (preventable or treatable) mechanisms for DGE is important. The aim of the manuscript was to test the hypothesis that ileal brake contributes to DGE in PD patients receiving jejunal tube feeding by systematically reviewing experimental and clinical literature. A series of clinically relevant questions were framed related to the potential role of the ileal brake in development of DGE post-PD and formed the basis of targeted literature searches. A comprehensive search of major reference databases from January 1980 to June 2015 was carried out which included human and animal studies. The ileal brake is a feedback loop neurally mediated by the vagus and sympatho-adrenergic pathways and hormonally by gut peptides including glucagon-like peptide-1, peptide YY (PYY), and neurotensin. The most potent stimulus for this inhibitory reflex is intra-ileal fat. There is evidence to indicate the role of an inhibitory reflex (on gastric emptying) mediated by PYY and CCK which, in turn, are stimulated by nutrient delivery into the distal small intestine providing indirect support to the role of ileal brake in post-PD DGE. The ileal brake is a likely factor contributing to DGE post-PD. While there has been no study to directly test this hypothesis, there is compelling indirect evidence to support it. Designing a trial that would answer such a question appears to be the most appropriate way forward.

Feed-forward neural network model for hunger and satiety related VAS score prediction

BACKGROUND

An artificial neural network approach was chosen to model the outcome of the complex signaling pathways in the gastro-intestinal tract and other peripheral organs that eventually produce the satiety feeling in the brain upon feeding.

METHODS

A multilayer feed-forward neural network was trained with sets of experimental data relating concentration-time courses of plasma satiety hormones to Visual Analog Scales (VAS) scores. The network successfully predicted VAS responses from sets of satiety hormone data obtained in experiments using different food compositions.

RESULTS

The correlation coefficients for the predicted VAS responses for test sets having i) a full set of three satiety hormones, ii) a set of only two satiety hormones, and iii) a set of only one satiety hormone were 0.96, 0.96, and 0.89, respectively. The predicted VAS responses discriminated the satiety effects of high satiating food types from less satiating food types both in orally fed and ileal infused forms.

CONCLUSIONS

From this application of artificial neural networks, one may conclude that neural network models are very suitable to describe situations where behavior is complex and incompletely understood. However, training data sets that fit the experimental conditions need to be available.

Surgical cure for type 2 diabetes by foregut or hindgut operations: a myth or reality? A systematic review

BACKGROUND

Bariatric surgery results in remission of type 2 diabetes mellitus in a significant proportion of patients. Animal research has proposed the foregut and hindgut hypotheses as possible mechanisms of remission of T2DM independent of weight loss. These hypotheses have formed the basis of investigational procedures designed to treat T2DM in non-obese (in addition to obese) patients. The aim of this study was to review the procedures that utilise the foregut and hindgut hypotheses to treat T2DM in humans.

METHODS

A systematic review was conducted to identify the investigational procedures performed in humans that are based on the foregut and hindgut hypotheses and then to assess their outcomes.

RESULTS

Twenty-four studies reported novel procedures to treat T2DM in humans; only ten utilised glycated haemoglobin A1c (HbA1c) in their definition of remission. Reported remission rates were 20-40 % for duodenal-jejunal bypass (DJB), 73-93 % for duodenal-jejunal bypass with sleeve gastrectomy (DJB-SG), 62.5-100 % for duodenal-jejunal bypass sleeve (DJBS) and 47-95.7 % for ileal interposition with sleeve gastrectomy (II-SG). When using a predetermined level of HbA1c to define remission, the remission rates were lower (27, 63, 0 and 65 %) for DJB, DJB-SG, DJBS and II-SG.

CONCLUSIONS

The outcomes of the foregut- and hindgut-based procedures are not better than the outcomes of just one of their components, namely sleeve gastrectomy. The complexity of these procedures in addition to their comparable outcomes to a simpler operation questions their utility.

Gut feedback mechanisms and food intake: a physiological approach to slow carbohydrate bioavailability

Glycemic carbohydrates in foods are an important macronutrient providing the biological fuel of glucose for a variety of physiological processes. A classification of glycemic carbohydrates into rapidly digestible carbohydrate (RDC) and slowly digestible carbohydrate (SDC) has been used to specify their nutritional quality related to glucose homeostasis that is essential to normal functioning of the brain and critical to life. Although there have been many studies and reviews on slowly digestible starch (SDS) and SDC, the mechanisms of their slow digestion and absorption were mostly investigated from the material side without considering the physiological processes of their in vivo digestion, absorption, and most importantly interactions with other food components and the gastrointestinal tract. In this article, the physiological processes modulating the bioavailability of carbohydrates, specifically the rate and extent of their digestion and absorption as well as the related locations, in a whole food context, will be discussed by focusing on the activities of the gastrointestinal tract including glycolytic enzymes and glucose release, sugar sensing, gut hormones, and neurohormonal negative feedback mechanisms. It is hoped that a deep understanding of these physiological processes will facilitate the development of innovative dietary approaches to achieve desired carbohydrate or glucose bioavailability for improved health.

Formulation and characterization of self-nanoemulsifying drug delivery systems containing monoacyl phosphatidylcholine

The study investigated the use of monoacyl phosphatidylcholine (MAPC) in self-nanoemulsifying drug delivery system (SNEDDS). A D-optimal design was used to generate two sets of formulations containing long-chain (LC) or medium-chain (MC) glycerides, caprylocaproyl macrogol-8 glycerides (Labrasol), Lipoid S LPC 80 (LPC) (80% MAPC) and ethanol. The formulations were characterized using dynamic light scattering, microscopy, in vitro lipolysis and viscometric measurements. All LC formulations within the investigated range were predicted to generate polydisperse emulsions while MC formulations generated nanoemulsions with droplet sizes from 23 to 167 nm. Using LPC in MC formulations reduced the nanoemulsion droplet sizes in simulated gastric and intestinal media. The nanoemulsion droplet size of MC SNEDDS containing LPC was not affected by gastrointestinal pH, while the zeta potentials increased at low pH. During in vitro lipolysis, less fatty acids were released when LPC was incorporated into the formulations (2.05 ± 0.02 mmol reduced to 1.76 ± 0.05 mmol when incorporating 30% LPC). Replacing Labrasol by LPC increased the formulation dynamic viscosity from 57 ± 1 mPas (0% LPC) to 436 ± 8 mPas (35% LPC) at 25°C, however, this did not considerably prolong the formulation dispersion time. In conclusion, MC SNEDDS containing LPC are promising formulations when desiring to reduce the amount of synthetic surfactants and possibly modify the digestion rate.

Functional food microstructures for macronutrient release and delivery

There is a need to understand the role of fat, protein and carbohydrate in human health, and also how foods containing and/or structured using these macronutrients can be designed so that they can have a positive impact on health. This may include a reduction in fat, salt or sugar, the protection and targeted release of micronutrients or active ingredients from/to particular parts of the digestive system, improvement of gastrointestinal health or satiety enhancing properties. Such foods can be designed with various macro- and microstructures that will impact on macronutrient release and delivery. These include simple and double emulsions, the use of Pickering particles and shells, nanoparticles, liposomes, gelled networks, fluid gels and gel particles, foams, self-assembled structures, and encapsulated systems. In order to design foods that deliver these benefits understanding of how these structures behave in the gastrointestinal tract is also required, which should involve utilising both in vitro and in vivo studies. This review aims to draw together research in these areas, by focusing on the current state of the art, but also exciting possibilities for future research and food development.

The role of the neuropeptide Y (NPY) family in the pathophysiology of inflammatory bowel disease (IBD)

Inflammatory bowel disease (IBD) includes three main disorders: ulcerative colitis, Crohn's disease, and microscopic colitis. The etiology of IBD is unknown and the current treatments are not completely satisfactory. Interactions between the gut neurohormones and the immune system are thought to play a pivot role in inflammation, especially in IBD. These neurohormones are believed to include members of the neuropeptide YY (NPY) family, which comprises NPY, peptide YY (PYY), and pancreatic polypeptide (PP). Understanding the role of these peptides may shed light on the pathophysiology of IBD and potentially yield an effective treatment tool. Intestinal NPY, PYY, and PP are abnormal in both patients with IBD and animal models of human IBD. The abnormality in NPY appears to be primarily caused by an interaction between immune cells and the NPY neurons in the enteric nervous system; the abnormalities in PYY and PP appear to be secondary to the changes caused by the abnormalities in other gut neurohormonal peptides/amines that occur during inflammation. NPY is the member of the NPY family that can be targeted in order to decrease the inflammation present in IBD.

Clinical management of post-pyloric enteral feeding in children

Post-pyloric feeding (PF) allows the administration of enteral nutrition beyond the pylorus, either into the duodenum or, ideally, into the jejunum. The main indications of PF are: upper gastrointestinal tract obstructions, pancreatic rest (e.g., acute pancreatitis), gastric dysmotility (e.g., critically ill patients and chronic intestinal pseudo-obstruction) or severe gastroesophageal reflux with risk of aspiration (e.g., neurological disability). Physiological and clinical evidence derives from adults, but can also be pertinent to children. This review will discuss the practical management and potential clinical applications of PF in pediatric patients. Some key studies pertaining to the physiological changes during PF will also be considered because they support the strategy of PF management.

Diet in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder that is characterized by intermittent abdominal pain/discomfort, altered bowel habits and abdominal bloating/distension. This review aimed at presenting the recent developments concerning the role of diet in the pathophysiology and management of IBS. There is no convincing evidence that IBS patients suffer from food allergy/intolerance, and there is no evidence that gluten causes the debated new diagnosis of non-coeliac gluten sensitivity (NCGS). The component in wheat that triggers symptoms in NCGS appears to be the carbohydrates. Patients with NCGS appear to be IBS patients who are self-diagnosed and self-treated with a gluten-free diet. IBS symptoms are triggered by the consumption of the poorly absorbed fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) and insoluble fibre. On reaching the distal small intestine and colon, FODMAPS and insoluble fibre increase the osmotic pressure in the large-intestine lumen and provide a substrate for bacterial fermentation, with consequent gas production, abdominal distension and abdominal pain or discomfort. Poor FODMAPS and insoluble fibres diet reduces the symptom and improve the quality of life in IBS patients. Moreover, it changes favourably the intestinal microbiota and restores the abnormalities in the gastrointestinal endocrine cells. Five gastrointestinal endocrine cell types that produce hormones regulating appetite and food intake are abnormal in IBS patients. Based on these hormonal abnormalities, one would expect that IBS patients to have increased food intake and body weight gain. However, the link between obesity and IBS is not fully studied. Individual dietary guidance for intake of poor FODMAPs and insoluble fibres diet in combination with probiotics intake and regular exercise is to be recommended for IBS patients.

Advances in oral nano-delivery systems for colon targeted drug delivery in inflammatory bowel disease: selective targeting to diseased versus healthy tissue

Colon targeted drug delivery is an active area of research for local diseases affecting the colon, as it improves the efficacy of therapeutics and enables localized treatment, which reduces systemic toxicity. Targeted delivery of therapeutics to the colon is particularly advantageous for the treatment of inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease. Advances in oral drug delivery design have significantly improved the bioavailability of drugs to the colon; however in order for a drug to have therapeutic efficacy during disease, considerations must be made for the altered physiology of the gastrointestinal (GI) tract that is associated with GI inflammation. Nanotechnology has been used in oral dosage formulation design as strategies to further enhance uptake into diseased tissue within the colon. This review will describe some of the physiological challenges faced by orally administered delivery systems in IBD, the important developments in orally administered nano-delivery systems for colon targeting, and the future advances of this research.

FROM THE CLINICAL EDITOR

Inflammatory Bowel Disease (IBD) poses a significant problem for a large number of patients worldwide. Current medical therapy mostly aims at suppressing the active inflammatory episodes. In this review article, the authors described and discussed the various approaches current nano-delivery systems can offer in overcoming the limitations of conventional drug formulations.

Gut hormones in the treatment of short-bowel syndrome and intestinal failure

PURPOSE OF REVIEW

The approval of teduglutide, a recombinant analog of human glucagon-like peptide (GLP) 2, by the US Food and Drug Administration (Gattex) and the European Medicines Agency (Revestive) has illustrated the potential of selected gut hormones as treatments in patients with short-bowel syndrome and intestinal failure. Gut hormones may improve the structural and functional intestinal adaptation following intestinal resection by decreasing a rapid gastric emptying and hypersecretion, by increasing the intestinal blood flow, and by promoting intestinal growth. This review summarizes the findings from phase 2 and 3 teduglutide studies, and pilot studies employing GLP-1 and agonists for this orphan condition.

RECENT FINDINGS

In a 3-week, phase 2, metabolic balance study, teduglutide increased the intestinal wet weight absorption by approximately 700 g/day and reduced fecal energy losses by approximately 0.8 MJ/day (∼200 Kcal/day). In two subsequent 24-week, phase 3 studies, teduglutide reduced the need for parenteral support in the same magnitude. Adverse events were mainly of gastrointestinal origin and consistent with the known mechanism of action of teduglutide. Pilot studies suggest that GLP-1 may be less potent. Synergistic effects may be seen by co-treatment with GLP-2.

SUMMARY

Gut hormones promote intestinal adaptation and absorption, decreasing fecal losses, thereby decreasing or even eliminating the need for parenteral support. This will aid the intestinal rehabilitation in these severely disabled short-bowel syndrome patients.

New approaches to the treatments of short bowel syndrome-associated intestinal failure

PURPOSE OF REVIEW

Teduglutide, a recombinant analog of human glucagon-like peptide 2, has recently been approved in the US and Europe (Gattex and Revestive, respectively) as the first targeted treatment of short bowel syndrome-associated intestinal failure (SBS-IF). Glucagon-like peptide 2 improves structural and functional intestinal adaptation following intestinal resection by decelerating a rapid gastric emptying, by decreasing gastric hypersecretion, by increasing intestinal blood flow and by promoting intestinal growth. This review summarizes the findings from phase 2 and 3 studies preceding the US Food and Drug Administration and the European Medicines Agency approval of subcutaneous teduglutide for this orphan condition.

RECENT FINDINGS

In a 3-week, phase 2, metabolic balance study, teduglutide increased intestinal wet weight absorption by approximately 700 g/day and reduced fecal energy losses by approximately 0.8 MJ/day (∼200 kcal/day). In two subsequent 24-week, phase 3 studies, teduglutide reduced the need for parenteral support in the same magnitude. Teduglutide had an acceptable tolerability profile, where adverse events generally were of gastrointestinal origin consistent with the known mechanism of action.

SUMMARY

Teduglutide will add incremental benefit to the limited medical treatment armamentarium in SBS patients by maximizing intestinal absorption, decreasing fecal losses, thereby decreasing or even eliminating the need for parenteral support. Future research should target and implement other key hormones with similar and possible additive or synergistic effects, thereby further promoting structural and functional adaptation and intestinal rehabilitation in these severely disabled SBS patients.

Lipids, CHOs, proteins: can all macronutrients put a 'brake' on eating?

The gastrointestinal (GI) tract and specifically the most distal part of the small intestine, the ileum, has become a renewed focus of interest for mechanisms targeting appetite suppression. The 'ileal brake' is stimulated when energy-containing nutrients are delivered beyond the duodenum and jejunum and into the ileum, and is named for the feedback loop which slows or 'brakes' gastric emptying and duodeno-jejunal motility. More recently it has been hypothesized that the ileal brake also promotes secretion of satiety-enhancing GI peptides and suppresses hunger, placing a 'brake' on food intake. Postprandial delivery of macronutrients to the ileum, other than unavailable carbohydrates (CHO) which bypass absorption in the small intestine en route to fermentation in the large bowel, is an uncommon event and hence this brake mechanism is rarely activated following a meal. However the ability to place a 'brake' on food intake through delivery of protected nutrients to the ileum is both intriguing and challenging. This review summarizes the current clinical and experimental evidence for activation of the ileal brake by the three food macronutrients, with emphasis on eating behavior and satiety as well as GI function. While clinical studies have shown that exposure of the ileum to lipids, CHOs and proteins may activate GI components of the ileal brake, such as decreased gut motility, gastric emptying and secretion of GI peptides, there is less evidence as yet to support a causal relationship between activation of the GI brake by these macronutrients and the suppression of food intake. The predominance of evidence for an ileal brake on eating comes from lipid studies, where direct lipid infusion into the ileum suppresses both hunger and food intake. Outcomes from oral feeding studies are less conclusive with no evidence that 'protected' lipids have been successfully delivered into the ileum in order to trigger the brake. Whether CHO or protein may induce the ileal brake and suppress food intake has to date been little investigated, although both clearly have GI mediated effects. This review provides an overview of the mechanisms and mediators of activation of the ileal brake and assesses whether it may play an important role in appetite suppression.

Digestive physiology of the pig symposium: potential applications of knowledge of gut chemosensing in pig production

Pig production is a commodity business, which makes it a cost-driven business. Pig producers and their advisors are appropriately reluctant to adopt technologies without confidence that improved production will more than pay for the cost of the technology. Physiological effects of technologies targeting gut sensory pathways must translate to demonstrably improved health and/or productive performance if they are to be adopted. The types and degrees of stressors experienced by pigs in commercial production vary widely and often differ from those in research herds, and those variations influence their productive responses to nutritional and health technologies. Pigs are most vulnerable to disease soon after weaning, and the diets fed to pigs at that time are more expensive and offered in much smaller amounts than those fed later in life. Those factors make it easier to justify expensive dietary technologies for young pigs than for older ones. New developments in gut chemosensing appear important, but their practical application is not yet clear. We suggest investigation of the potential to connect chemical detection by the gut to pig productivity and/or efficiency through these mechanisms: 1) trophic effects on the intestines, which lead to improved enteric health or enhanced nutrient digestion and absorption, 2) enhanced barrier function in the intestinal mucosa, 3) increased feed intake, 4) enhanced insulin secretion and sensitivity, which may be especially useful in lactating sows to improve subsequent reproduction, and 5) other signals triggered by products of enteric fermentation, possibly short-chain fatty acids, that may influence gut integrity, feed intake, and reproductive function. Each of these mechanisms relates to a practical issue in pig production. Practical application would likely be achieved through dietary changes, but separate management factors, drugs, or other interventions may also be developed.

Dietary strategies to increase satiety

Obesity has a multifactorial etiology. Although obesity is widespread and associated with serious health hazards, its effective prevention and treatment have been challenging. Among the currently available treatment approaches, lifestyle modification to induce a negative energy balance holds a particularly larger appeal due to its wider reach and relative safety. However, long-term compliance with dietary modifications to reduce energy intake is not effective for the majority. The role of many individual nutrients, foods, and food groups in inducing satiety has been extensively studied. Based on this evidence, we have developed sample weight-loss meal plans that include multiple satiating foods, which may collectively augment the satiating properties of a meal. Compared to a typical American diet, these meal plans are considerably lower in energy density and probably more satiating. A diet that exploits the satiating properties of multiple foods may help increase long-term dietary compliance and consequentially enhance weight loss.

A role for neuropeptide Y in the gender-specific gastrointestinal, corticosterone and feeding responses to stress

BACKGROUND AND PURPOSE

Exposure to an acute stress inhibits gastric emptying and stimulates colonic transit via central neuropeptide Y (NPY) pathways; however, peripheral involvement is uncertain. The anxiogenic phenotype of NPY(-/-) mice is gender-dependent, raising the possibility that stress-induced gastrointestinal (GI) responses are female-dominant through NPY. The aim of this study was to determine GI transit rates, corticosterone levels and food intake after acute restraint (AR) or novel environment (NE) stress in male and female NPY(-/-) and WT mice.

EXPERIMENTAL APPROACH

Upper gastrointestinal transit (UGIT) (established 30 min after oral gavage) and corticosterone levels were determined under basal or restrained conditions (30 min) and after treatment i.p. with Y(1) antagonist BIBO3304 or Y(2) antagonist BIIE0246. Faecal pellet output (FPO) was established after AR and treatment i.p. with NPY in the NE, as were colonic bead expulsion rates.

KEY RESULTS

UGIT and FPO were similar in unrestrained male and female mice. NPY(-/-) females displayed significantly slower UGIT than NPY(-/-) males after AR, but both genders displayed significantly higher FPO and reduced food intake relative to WT counterparts. Peripheral NPY treatment increased bead expulsion time in WT mice. AR male NPY(-/-) mice had higher levels of corticosterone than male WT mice; whilst in AR WT mice, after peripheral Y(1) and Y(2) receptor antagonism in males, and Y(2) antagonism in females, corticosterone was significantly elevated.

CONCLUSIONS AND IMPLICATIONS

NPY possesses a role in the gender-dependent susceptibility to stress-induced GI responses. Furthermore, NPY inhibits GI motility through Y(2) receptors and corticosterone release via peripheral Y(1) and Y(2) receptors.

Efficacy of Olibra: a 12-week randomized controlled trial and a review of earlier studies

BACKGROUND

Intervention strategies that harness the body's appetite and satiety regulating signals provide a means of countering excessive energy intake.

METHODS

Eighty-two subjects were enrolled (18-60 years, body mass index: 25-40 kg/m(2)) in a randomized, placebo-controlled, double-blind, parallel trial. During a 12-week period, the effects of Olibra™ fat emulsion (2.1 g twice daily) on food intake, appetite, satiety, weight, and body composition were compared with those of a twice daily administered placebo (1.95 g milk fat). On days -7, 0, and 28, Olibra or the placebo added to 200 g of yogurt was served at breakfast and lunch. Food intake, appetite, and satiety were assessed after lunch and dinner. Body weight was measured on days -7, 0, 14, 28, 56, and 84. Body fat, waist circumference, and waist-hip ratio were determined on days 0 and 84. The Eating Inventory was administered at screening and on day 28. Data relating to 71 subjects were analyzed using analysis of covariance.

RESULTS

At 12 weeks, body weight was reduced in the test group (2.17 ± 0.46 kg standard error of the mean, p < .0001) and the control group (1.68 ± 0.42 kg, p < .0001). Waist circumference decreased by 2.93 ± 0.85 cm in the test group (p = .001) and by 1.78 ± 0.74 cm in the control group (p = .02). Differential weight and waist circumference reductions were not significant. Hunger scores (Eating Inventory) decreased more in the test group (p = .0082). Differential group effects were not significant for body fat, waist-hip ratio, food intake, appetite, and satiety.

CONCLUSIONS

At this dose, Olibra did not exert a consistent effect on food intake, appetite regulation, body weight, or body composition.

Changes in gastrointestinal hormones and leptin after Roux-en-Y gastric bypass surgery

BACKGROUND

Roux-en-Y gastric bypass (RYGB) imparts long-term weight loss, the mechanisms for which are not well understood. Changes in leptin and gastrointestinal (GI) hormones, including glucagon-like peptide 1 (GLP-1), peptide YY (PYY), and ghrelin, may contribute to the relative success of RYGB compared with conventional weight loss methods. This study evaluated changes in GI hormones and leptin post-RYGB. The study also evaluated whether GI hormones differed after a short-term dose of protein or fat.

METHODS

GLP-1, PYY, ghrelin, and leptin were assessed in 16 women before RYGB and up to 1 year after RYGB. Plasma was collected before and at several times after a short-term equicaloric dose of protein or fat.

RESULTS

GLP-1 area under the curve (AUC) increased at week 6 and 1 year in the fat beverage (FAT-BEV) group compared with baseline. PYY AUC remained elevated at 1 year in the FAT-BEV group. Ghrelin AUC decreased at week 2, week 6, and 1 year in the protein beverage (PRO-BEV) group compared with baseline. Ghrelin AUC was lower in the PRO-BEV group compared with the FAT-BEV group at week 6. Fasted leptin decreased at all visits in both groups and was lower in the FAT-BEV group compared with the PRO-BEV group at 1 year.

CONCLUSIONS

Changes from baseline were evident for all GI hormones and leptin; some differences were evident soon after surgery (ghrelin, leptin), whereas others were maintained long term (GLP-1, PYY, ghrelin, leptin). In response to a short-term stimulus, protein suppressed ghrelin and fat potently stimulated GLP-1 and PYY. Future work in this area is warranted.

Gastric motility physiology and surgical intervention

Disordered gastric motility represents a spectrum of dysfunction ranging from delayed gastric emptying to abnormally rapid gastric transit, commonly referred to as the "dumping syndrome." Both extremes of gastric motility disorders can arise from similar pathologic processes, and produce remarkably identical symptoms. This fact underscores the need to attain a precise diagnosis to ensure the institution of optimal therapy. Disordered gastric motility is primarily managed with dietary modification followed by pharmacotherapy, as traditional surgical interventions tend to be fraught with complications. However, continued improvements in minimally invasive diagnostic and therapeutic modalities promise novel options for earlier and more effective treatment.

Efficacy of the glucagon-like peptide-1 agonist exenatide in the treatment of short bowel syndrome

BACKGROUND

Short bowel syndrome (SBS) is a serious clinical disorder characterized by diarrhea and nutritional deprivation. Glucagon-like peptide-1 (GLP-1) is a key hormone, produced by L-cells in the ileum, that regulates proximal gut transit. When extensive ileal resection occurs, as in SBS, GLP-1 levels may be deficient. In this study, we test whether the use of GLP-1 agonist exenatide can improve the nutritional state and intestinal symptoms of patients with SBS.

METHODS

Five consecutive patients with SBS based on ≤90 cm of small bowel and clinical evidence of nutritional deprivation were selected. Baseline SBS symptoms, demographic and laboratory data were obtained. Antroduodenal manometry was performed on each subject. Each patient was then started on exenatide and over the following month, the baseline parameters were repeated.

KEY RESULTS

The subjects consisted of four males and one female, aged 46-69 years. At baseline, all had severe diarrhea that ranged from 6 to 15 bowel movements per day, often occurring within minutes of eating. After exenatide, all five patients had immediate improvement in bowel frequency and form; bowel movements were no longer meal-related. Total parenteral nutrition was stopped successfully in three patients. Antroduodenal manometry revealed continuous low amplitude gastric contractions during fasting which completely normalized with exenatide.

CONCLUSIONS & INFERENCES

Exenatide is a novel and safe treatment option for SBS. It produced substantial improvement in the bowel habits, nutritional status and quality of life of SBS patients. Successful treatment with exenatide may significantly reduce the need for parenteral nutrition and small bowel transplant.

Sleeve gastrectomy with ileal transposition (SGIT) induces a significant weight loss and diabetes improvement without exclusion of the proximal intestine

INTRODUCTION

Current effective bariatric procedures such as gastric bypass generate a duodenal-jejunal exclusion, which has been implicated in the resolution of type 2 diabetes. The aim of this study was to test the hypothesis that sleeve gastrectomy with ileal transposition (SGIT), a new procedure, is as effective as Roux-en-Y gastric bypass (RYGB) to induce glucose control on an obese rat model of type 2 diabetes mellitus.

METHODS

Twenty eight obese diabetic Zucker rats, weighing 571 ± 151 g were assigned into three procedures: SGIT (n = 11), RYGB (n = 7), and sham operation (n = 10). Animals were followed, evaluating weekly weight increase and food intake. We performed an insulin tolerance test after 8 weeks and measured serum peptide tyrosine-tyrosine (PYY 3-36) and ghrelin levels.

RESULTS

Nine weeks after surgery, sham-operated animals increased their body weight by 24%. In far contrast, SGIT and RYGB rats weighed 21% and 18% less than sham animals, respectively (sham, 884 ± 15 g; SGIT, 720 ± 19 g; RYGB, 754 ± 14 g; p < 0.001). No significant differences were found between SGIT and RYGB. Cumulative food intake in SGIT and RYGB procedures decreased by 29.6% and 32.9%, respectively (sham, 576.3 ± 33 g; SGIT, 405.8 ± 10 g; RYGB, 386.4 ± 21 g; p < 0.001). No differences were found between SGIT and RYGB rats. Sixty minutes after oral gavage, PYY levels were increased by 185% and 74% in SGIT and RYGB, respectively (sham, 63.4 ± 2.1 pg/ml; SGIT, 192.7 ± 17 pg/ml; RYGB, 117.7 ± 4.8 pg/ml; p < 0.001). Glucose tolerance was improved after SGIT and RYGB surgery demonstrated by area under the curve analysis (sham, 27,090 ± 1,424; SGIT, 17,704 ± 1,288 mg/dl; p < 0.018; RYGB, 16,212 ± 2,522; p < 0.01).

CONCLUSION

SGIT proved to be as effective as RYGB on obese diabetic rats as a weight loss procedure. Also, glucose homeostasis improved in SGIT, similar to RYGB, in spite of the absence of duodenal-jejunal exclusion. This observation does not support the theory that RYGB reversal of diabetes is due to duodenal-jejunal exclusion.