Teduglutide, a novel mucosally active analog of glucagon-like peptide-2 (GLP-2) for the treatment of moderate to severe Crohn's disease

Therapeutic stapled peptides: Efficacy and molecular targets

Peptide stapling, by employing a stable, preformed alpha-helical conformation, results in the production of peptides with improved membrane permeability and enhanced proteolytic stability, compared to the original peptides, and provides an effective solution to accelerate the rapid development of peptide drugs. Various reviews present peptide stapling chemistries, anchoring residues and one- or two-component cyclization, however, therapeutic stapled peptides have not been systematically summarized, especially focusing on various disease-related targets. This review highlights the latest advances in therapeutic peptide drug development facilitated by the application of stapling technology, including different stapling techniques, synthetic accessibility, applicability to biological targets, potential for solving biological problems, as well as the current status of development. Stapled peptides as therapeutic drug candidates have been classified and analysed mainly by receptor- and ligand-based stapled peptide design against various diseases, including cancer, infectious diseases, inflammation, and diabetes. This review is expected to provide a comprehensive reference for the rational design of stapled peptides for different diseases and targets to facilitate the development of therapeutic peptides with enhanced pharmacokinetic and biological properties.

A nanoparticle platform for combined mucosal healing and immunomodulation in inflammatory bowel disease treatment

Current treatments for inflammatory bowel disease (IBD) treatment consist of anti-inflammatory products. In this study, we sought to induce the physiological secretion of glucagon-like peptide 2, a peptide with intestinal growth-promoting activity, via nanoparticles while simultaneously providing with immunomodulation by tailoring the nanoparticle surface. To this end, we developed hybrid lipid hyaluronate-KPV conjugated nanoparticles loaded with teduglutide for combination therapy in IBD. The nanocarriers induced (or did not induce) immunosuppression depending on the presence (or absence) of a hyaluronan-KPV functionalization. This strategy holds promise as a nanoparticle platform for combined mucosal healing and immunomodulation in IBD treatment.

Potential Application of Intestinal Organoids in Intestinal Diseases

To accurately reveal the scenario and mecahnism of gastrointestinal diseases, the establishment of in vitro models of intestinal diseases and drug screening platforms have become the focus of attention. Over the past few decades, animal models and immortalized cell lines have provided valuable but limited insights into gastrointestinal research. In recent years, the development of intestinal organoid culture system has revolutionized in vitro studies of intestinal diseases. Intestinal organoids are derived from self-renewal and self-organization intestinal stem cells (ISCs), which can replicate the genetic characteristics, functions, and structures of the original tissues. Consequently, they provide new stragety for studying various intestinal diseases in vitro. In the review, we will discuss the culture techniques of intestinal organoids and describe the use of intestinal organoids as research tools for intestinal diseases. The role of intestinal epithelial cells (IECs) played in the pathogenesis of inflammatory bowel diseases (IBD) and the treatment of intestinal epithelial dysfunction will be highlighted. Besides, we review the current knowledge on using intestinal organoids as models to study the pathogenesis of IBD caused by epithelial dysfunction and to develop new therapeutic approaches. Finally, we shed light on the current challenges of using intestinal organoids as in vitro models.

Chemotherapy-induced gastrointestinal toxicity: Pathogenesis and current management

Chemotherapy is the most common treatment for malignant tumors. However, chemotherapy-induced gastrointestinal toxicity (CIGT) has been a major concern for cancer patients, which reduces their quality of life and leads to treatment intolerance and even cessation. Nevertheless, prevention and treatment for CIGT are challenging, due to the prevalence and complexity of the condition. Chemotherapeutic drugs directly damage gastrointestinal mucosa to induce CIGT, including nausea, vomiting, anorexia, gastrointestinal mucositis, and diarrhea, etc. The pathogenesis of CIGT involves multiple factors, such as gut microbiota disorders, inflammatory responses and abnormal neurotransmitter levels, that synergistically contribute to its occurrence and development. In particular, the dysbiosis of gut microbiota is usually linked to abnormal immune responses that increases inflammatory cytokines' expression, which is a common characteristic of many types of CIGT. Chemotherapy-induced intestinal neurotoxicity is also a vital concern in CIGT. Currently, modern medicine is the dominant treatment of CIGT, however, traditional Chinese medicine (TCM) has attracted interest as a complementary and alternative therapy that can greatly alleviate CIGT. Accordingly, this review aimed to comprehensively summarize the pathogenesis and current management of CIGT using PubMed and Google Scholar databases, and proposed that future research for CIGT should focus on the gut microbiota, intestinal neurotoxicity, and promising TCM therapies, which may help to develop more effective interventions and optimize managements of CIGT.

Are gut dysbiosis, barrier disruption, and endotoxemia related to adipose tissue dysfunction in metabolic disorders? Overview of the mechanisms involved

Recently, compelling evidence points to dysbiosis and disruption of the epithelial intestinal barrier as major players in the pathophysiology of metabolic disorders, such as obesity. Upon the intestinal barrier disruption, components from bacterial metabolism and bacteria itself can reach peripheral tissues through circulation. This has been associated with the low-grade inflammation that characterizes obesity and other metabolic diseases. While circulating bacterial DNA has been postulated as a common feature of obesity and even type 2 diabetes, almost no focus has been given to the existence and effects of bacteria in peripheral tissues, namely the adipose tissue. As a symbiont population, it is expected that gut microbiota modulate the immunometabolism of the host, thus influencing energy balance mechanisms and inflammation. Gut inflammatory signals cause direct deleterious inflammatory responses in adipose tissue and may also affect key gut neuroendocrine mechanisms governing nutrient sensing and energy balance, like incretins and ghrelin, which play a role in the gut-brain-adipose tissue axis. Thus, it is of major importance to disclose how gut microbiota and derived signals modulate neuroendocrine and inflammatory pathways, which contribute to the dysfunction of adipose tissue and to the metabolic sequelae of obesity and related disorders. This review summarizes the current knowledge regarding these topics and identifies new perspectives in this field of research, highlighting new pathways toward the reduction of the inflammatory burden of metabolic diseases.

Glepaglutide, a novel glucagon-like peptide-2 agonist, has anti-inflammatory and mucosal regenerative effects in an experimental model of inflammatory bowel disease in rats

BACKGROUND

Glucagon-like peptide-2 (GLP-2) enhances intestinal repair and attenuates inflammation in preclinical inflammatory bowel disease (IBD) models, making GLP-2 analogues attractive candidates for IBD therapy. Glepaglutide is a long-acting GLP-2 receptor agonist in clinical development for treatment of short bowel syndrome. Here, we investigated if glepaglutide is therapeutically beneficial in rats with small intestinal inflammation.

METHODS

Small intestinal inflammation was induced with indomethacin in naive Wistar rats, followed by glepaglutide administration at different disease stages. Glepaglutide was administered in co-treatment and post-treatment regimens. Small intestinal length and concentrations of inflammatory markers α-1-acid glycoprotein and myeloperoxidase were used to assess anti-inflammatory effects. Small intestinal mass was evaluated to determine intestinotrophic effects.

RESULTS

Glepaglutide co- and post-treatment significantly reduced severity of small intestinal inflammation, evidenced by reversed small intestinal shortening and decreased α-1-acid glycoprotein and/or myeloperoxidase concentration(s). Co- and post-treatment with glepaglutide also significantly increased small intestinal mass, indicating intestinal regenerative effects. Similar effects were observed in naive rats after glepaglutide treatment.

CONCLUSION

Glepaglutide has anti-inflammatory and intestinotrophic effects without the need for pre-treatment in a rat model of small intestinal inflammation. Thus, glepaglutide is of potential clinical interest for patients with IBD.

Biodegradable Polymeric Nanoparticles Loaded with Flavonoids: A Promising Therapy for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a group of disorders that cause chronic non-specific inflammation in the gastrointestinal (GI) tract, primarily affecting the ileum and colon. The incidence of IBD has risen sharply in recent years. Despite continuous research efforts over the past decades, the aetiology of IBD is still not fully understood and only a limited number of drugs are available for its treatment. Flavonoids, a ubiquitous class of natural chemicals found in plants, have been widely used in the prevention and treatment of IBD. However, their therapeutic efficacy is unsatisfactory due to poor solubility, instability, rapid metabolism, and rapid systemic elimination. With the development of nanomedicine, nanocarriers can efficiently encapsulate various flavonoids and subsequently form nanoparticles (NPs), which greatly improves the stability and bioavailability of flavonoids. Recently, progress has also been made in the methodology of biodegradable polymers that can be used to fabricate NPs. As a result, NPs can significantly enhance the preventive or therapeutic effects of flavonoids on IBD. In this review, we aim to evaluate the therapeutic effect of flavonoid NPs on IBD. Furthermore, we discuss possible challenges and future perspectives.

Therapeutic Potential of GLP-2 Analogs in Gastrointestinal Disorders: Current Knowledge, Nutritional Aspects, and Future Perspectives

PURPOSE OF REVIEW

Although Glucagon-like peptide (GLP)-1 receptor agonists have been used for almost two decades in the treatment of diabetes mellitus type 2 and, lately, in obesity, recent years have seen an increasing interest in the pharmacological agonism of other proglucagon-derived peptides, including GLP-2. Herein, we aimed to review the available evidence on the effects of GLP-2 agonism from animal and clinical studies. Furthermore, we summarize the current clinical applications of GLP-2 agonists among patients with intestinal failure associated with short bowel syndrome (SBS-IF) as well as potential future expansion of their indications to other intestinal disorders.

RECENT FINDINGS

Evidence from preclinical studies has highlighted the cellular trophic and functional beneficial actions of GLP-2 on small intestinal and colonic mucosa. Subsequently, pharmacologic agonism of GLP-2 has gathered interest for the treatment of patients with conditions pertaining to the loss of intestinal anatomical and/or functional integrity to a degree requiring parenteral support, collectively referred to as intestinal failure. GLP-2 analogs positively influence nutrient absorption in animal models and humans, although continued therapy is likely needed for sustained effects. The degradation-resistant GLP-2-analog teduglutide has received approval for the treatment of SBS-IF, in which it may decisively reduce patient dependency on parenteral support and improve quality of life. Another two longer-acting analogs, glepaglutide and apraglutide, are currently undergoing phase III clinical trials. The use of GLP-2 analogs is effective in the management of SBS-IF and may show promise in the treatment of other severe gastrointestinal disorders associated with loss of effective intestinal resorptive surface area.

Glucagon-like peptide-2 analogues for Crohn’s disease patients with short bowel syndrome and intestinal failure

Short bowel syndrome (SBS) with intestinal failure (IF) is a rare but severe complication of Crohn’s disease (CD), which is the most frequent benign condition that leads to SBS after repeated surgical resections, even in the era of biologics and small molecules. Glucagon-like peptide-2 analogues have been deeply studied recently for the treatment of SBS-IF. These drugs have a significant intestinotrophic effect and the potential to reduce the chronic dependence of SBS-IF patients on parenteral support or nutrition. Teduglutide has been approved for the treatment of SBS-IF, and apraglutide is currently in clinical development. The use of these drugs was examined with a focus on their use in CD patients.

GLP-1 and GLP-2 Orchestrate Intestine Integrity, Gut Microbiota, and Immune System Crosstalk

The intestine represents the body’s largest interface between internal organs and external environments except for its nutrient and fluid absorption functions. It has the ability to sense numerous endogenous and exogenous signals from both apical and basolateral surfaces and respond through endocrine and neuronal signaling to maintain metabolic homeostasis and energy expenditure. The intestine also harbours the largest population of microbes that interact with the host to maintain human health and diseases. Furthermore, the gut is known as the largest endocrine gland, secreting over 100 peptides and other molecules that act as signaling molecules to regulate human nutrition and physiology. Among these gut-derived hormones, glucagon-like peptide 1 (GLP-1) and -2 have received the most attention due to their critical role in intestinal function and food absorption as well as their application as key drug targets. In this review, we highlight the current state of the literature that has brought into light the importance of GLP-1 and GLP-2 in orchestrating intestine–microbiota–immune system crosstalk to maintain intestinal barrier integrity, inflammation, and metabolic homeostasis.

Mechanisms of mucosal healing: treating inflammatory bowel disease without immunosuppression?

Almost all currently available treatments for inflammatory bowel disease (IBD) act by inhibiting inflammation, often blocking specific inflammatory molecules. However, given the infectious and neoplastic disease burden associated with chronic immunosuppressive therapy, the goal of attaining mucosal healing without immunosuppression is attractive. The absence of treatments that directly promote mucosal healing and regeneration in IBD could be linked to the lack of understanding of the underlying pathways. The range of potential strategies to achieve mucosal healing is diverse. However, the targeting of regenerative mechanisms has not yet been achieved for IBD. Stem cells provide hope as a regenerative treatment and are used in limited clinical situations. Growth factors are available for the treatment of short bowel syndrome but have not yet been applied in IBD. The therapeutic application of organoid culture and stem cell therapy to generate new intestinal tissue could provide a novel mechanism to restore barrier function in IBD. Furthermore, blocking key effectors of barrier dysfunction (such as MLCK or damage-associated molecular pattern molecules) has shown promise in experimental IBD. Here, we review the diversity of molecular targets available to directly promote mucosal healing, experimental models to identify new potential pathways and some of the anticipated potential therapies for IBD.

Mechanisms of mucosal healing: treating inflammatory bowel disease without immunosuppression?

Almost all currently available treatments for inflammatory bowel disease (IBD) act by inhibiting inflammation, often blocking specific inflammatory molecules. However, given the infectious and neoplastic disease burden associated with chronic immunosuppressive therapy, the goal of attaining mucosal healing without immunosuppression is attractive. The absence of treatments that directly promote mucosal healing and regeneration in IBD could be linked to the lack of understanding of the underlying pathways. The range of potential strategies to achieve mucosal healing is diverse. However, the targeting of regenerative mechanisms has not yet been achieved for IBD. Stem cells provide hope as a regenerative treatment and are used in limited clinical situations. Growth factors are available for the treatment of short bowel syndrome but have not yet been applied in IBD. The therapeutic application of organoid culture and stem cell therapy to generate new intestinal tissue could provide a novel mechanism to restore barrier function in IBD. Furthermore, blocking key effectors of barrier dysfunction (such as MLCK or damage-associated molecular pattern molecules) has shown promise in experimental IBD. Here, we review the diversity of molecular targets available to directly promote mucosal healing, experimental models to identify new potential pathways and some of the anticipated potential therapies for IBD.

A Novel Pathway of Flavonoids Protecting against Inflammatory Bowel Disease: Modulating Enteroendocrine System

Inflammatory bowel disease (IBD) is a comprehensive term for chronic or relapsing inflammatory diseases occurring in the intestinal tract, generally including Crohn's disease (CD) and ulcerative colitis (UC). Presently, the pathogenesis of IBD is unknown, yet multiple factors have been reported to be related with the development of IBD. Flavonoids are phytochemicals with biological activity, which are ubiquitously distributed in edible plants, such as fruits and vegetables. Recent studies have demonstrated impressively that flavonoids have anti-IBD effects through multiple mechanisms. These include anti-inflammatory and antioxidant actions; the preservation of the epithelial barrier integrity, the intestinal immunomodulatory property, and the shaping microbiota composition and function. In addition, a few studies have shown the impact of flavonoids on enterohormones release; nonetheless, there is hardly any work showing the link between flavonoids, enterohormones release and IBD. So far, the interaction between flavonoids, enterohormones and IBD is elucidated for the first time in this review. Furthermore, the inference can be drawn that flavonoids may protect against IBD through modulating enterohormones, such as glucagon-like peptide 1 (GLP-1), GLP-2, dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors), ghrelin and cholecystokinin (CCK). In conclusion, this manuscript explores a possible mechanism of flavonoids protecting against IBD.

Autonomic Nervous System Neuroanatomical Alterations Could Provoke and Maintain Gastrointestinal Dysbiosis in Autism Spectrum Disorder (ASD): A Novel Microbiome-Host Interaction Mechanistic Hypothesis

Dysbiosis secondary to environmental factors, including dietary patterns, antibiotics use, pollution exposure, and other lifestyle factors, has been associated to many non-infective chronic inflammatory diseases. Autism spectrum disorder (ASD) is related to maternal inflammation, although there is no conclusive evidence that affected individuals suffer from systemic low-grade inflammation as in many psychological and psychiatric diseases. However, neuro-inflammation and neuro-immune abnormalities are observed within ASD-affected individuals. Rebalancing human gut microbiota to treat disease has been widely investigated with inconclusive and contradictory findings. These observations strongly suggest that the forms of dysbiosis encountered in ASD-affected individuals could also originate from autonomic nervous system (ANS) functioning abnormalities, a common neuro-anatomical alteration underlying ASD. According to this hypothesis, overactivation of the sympathetic branch of the ANS, due to the fact of an ASD-specific parasympathetic activity deficit, induces deregulation of the gut-brain axis, attenuating intestinal immune and osmotic homeostasis. This sets-up a dysbiotic state, that gives rise to immune and osmotic dysregulation, maintaining dysbiosis in a vicious cycle. Here, we explore the mechanisms whereby ANS imbalances could lead to alterations in intestinal microbiome-host interactions that may contribute to the severity of ASD by maintaining the brain-gut axis pathways in a dysregulated state.

Research-Based Product Innovation to Address Critical Unmet Needs of Patients with Inflammatory Bowel Diseases

Despite progress in recent decades, patients with inflammatory bowel diseases face many critical unmet needs, demonstrating the limitations of available treatment options. Addressing these unmet needs will require interventions targeting multiple aspects of inflammatory bowel disease pathology, including disease drivers that are not targeted by available therapies. The vast majority of late-stage investigational therapies also focus primarily on a narrow range of fundamental mechanisms. Thus, there is a pressing need to advance to clinical stage differentiated investigational therapies directly targeting a broader range of key mechanistic drivers of inflammatory bowel diseases. In addition, innovations are critically needed to enable treatments to be tailored to the specific underlying abnormal biological pathways of patients; interventions with improved safety profiles; biomarkers to develop prognostic, predictive, and monitoring tests; novel devices for nonpharmacological approaches such as minimally invasive monitoring; and digital health technologies. To address these needs, the Crohn's & Colitis Foundation launched IBD Ventures, a venture philanthropy-funding mechanism, and IBD Innovate®, an innovative, product-focused scientific conference. This special IBD Innovate® supplement is a collection of articles reflecting the diverse and exciting research and development that is currently ongoing in the inflammatory bowel disease field to deliver innovative and differentiated products addressing critical unmet needs of patients. Here, we highlight the pipeline of new product opportunities currently advancing at the preclinical and early clinical development stages. We categorize and describe novel and differentiated potential product opportunities based on their potential to address the following critical unmet patient needs: (1) biomarkers for prognosis of disease course and prediction/monitoring of treatment response; (2) restoration of eubiosis; (3) restoration of barrier function and mucosal healing; (4) more effective and safer anti-inflammatories; (5) neuromodulatory and behavioral therapies; (6) management of disease complications; and (7) targeted drug delivery.

The Role of Dipeptidyl Peptidase 4 as a Therapeutic Target and Serum Biomarker in Inflammatory Bowel Disease: A Systematic Review

BACKGROUND

The roles dipeptidyl peptidase 4 (DPP4), aminopeptidase N (APN), and their substrates in autoimmune diseases are being increasingly recognized. However, their significance in inflammatory bowel diseases (IBD) is not entirely understood. This systematic review aims to discuss the pathophysiological processes related to these ectopeptidases while comparing findings from preclinical and clinical settings.

METHODS

This review was conducted according to the PRISMA guidelines. We performed a literature search in PubMed, SCOPUS, and Web of Science to identify all reports from inception until February 2020. The search included validated animal models of intestinal inflammation and studies in IBD patients. Quality assessment was performed using SYRCLE's risk of bias tool and CASP qualitative and cohort checklists.

RESULTS

From the 45 included studies, 36 were performed in animal models and 12 in humans (3 reports included both). Overall, the methodological quality of preclinical studies was acceptable. In animal models, DPP4 and APN inhibition significantly improved intestinal inflammation.Glucagon-like peptide (GLP)-1 and GLP-2 analogs and GLP-2-relase-inducing drugs also showed significant benefits in recovery from inflammatory damage. A nonsignificant trend toward disease remission with the GLP-2 analog teduglutide was observed in the sole interventional human study. All human studies reported an inverse correlation between soluble DPP4/CD26 levels and disease severity, in accordance with the proposal of DPP4 as a biomarker for IBD.

CONCLUSIONS

The use of DPP4 inhibitors and analogs of its substrates has clear benefits in the treatment of experimentally induced intestinal inflammation. Further research is warranted to validate their potential diagnostic and therapeutic applications in IBD patients.

Acute Low-Intensity Treadmill Running Upregulates the Expression of Intestinal Glucose Transporters via GLP-2 in Mice

The effects of exercise on nutrient digestion and absorption in the intestinal tract are not well understood. A few studies have reported that exercise training increases the expression of molecules involved in carbohydrate digestion and absorption. Exercise was also shown to increase the blood concentration of glucagon-like peptide-2 (GLP-2), which regulates carbohydrate digestion and absorption in the small intestine. Therefore, we investigated the effects of exercise on the expression of molecules involved in intestinal digestion and absorption, including GLP-2. Six-week-old male mice were divided into a sedentary (SED) and low-intensity exercise (LEx) group. LEx mice were required to run on a treadmill (12.5 m/min, 1 h), whereas SED mice rested. All mice were euthanized 1 h after exercise or rest, and plasma, jejunum, ileum, and colon samples were collected, followed by analysis via IHC, EIA, and immunoblotting. The levels of plasma GLP-2 and the jejunum expression of the GLP-2 receptor, sucrase-isomaltase (SI), and glucose transporter 2 (GLUT2) were higher in LEx mice. Thus, we showed that acute low-intensity exercise affects the expression of molecules involved in intestinal carbohydrate digestion and absorption via GLP-2. Our results suggest that exercise might be beneficial for small intestine function in individuals with intestinal frailty.

Therapeutic Advances in Diabetes, Autoimmune, and Neurological Diseases

Since 2015, 170 small molecules, 60 antibody-based entities, 12 peptides, and 15 gene- or cell-therapies have been approved by FDA for diverse disease indications. Recent advancement in medicine is facilitated by identification of new targets and mechanisms of actions, advancement in discovery and development platforms, and the emergence of novel technologies. Early disease detection, precision intervention, and personalized treatments have revolutionized patient care in the last decade. In this review, we provide a comprehensive overview of current and emerging therapeutic modalities developed in the recent years. We focus on nine diseases in three major therapeutics areas, diabetes, autoimmune, and neurological disorders. The pathogenesis of each disease at physiological and molecular levels is discussed and recently approved drugs as well as drugs in the clinic are presented.

Gut Hormones in Health and Obesity: The Upcoming Role of Short Chain Fatty Acids

We are currently facing an obesity pandemic, with worldwide obesity rates having tripled since 1975. Obesity is one of the main risk factors for the development of non-communicable diseases, which are now the leading cause of death worldwide. This calls for urgent action towards understanding the underlying mechanisms behind the development of obesity as well as developing more effective treatments and interventions. Appetite is carefully regulated in humans via the interaction between the central nervous system and peripheral hormones. This involves a delicate balance in external stimuli, circulating satiating and appetite stimulating hormones, and correct functioning of neuronal signals. Any changes in this equilibrium can lead to an imbalance in energy intake versus expenditure, which often leads to overeating, and potentially weight gain resulting in overweight or obesity. Several lines of research have shown imbalances in gut hormones are found in those who are overweight or obese, which may be contributing to their condition. Therefore, this review examines the evidence for targeting gut hormones in the treatment of obesity by discussing how their dysregulation influences food intake, the potential possibility of altering the circulating levels of these hormones for treating obesity, as well as the role of short chain fatty acids and protein as novel treatments.

Immunomodulatory and Anti-Inflammatory Strategies to Reduce Comorbidity Risk in People with HIV

PURPOSE OF REVIEW

In this review, we will discuss treatment interventions targeting drivers of immune activation and chronic inflammation in PWH.

RECENT FINDINGS

Potential treatment strategies to prevent the progression of comorbidities in PWH have been identified. These studies include, among others, the use of statins to modulate lipid alterations and subsequent innate immune receptor activation, probiotics to restore healthy gut microbiota and reduce microbial translocation, hydroxychloroquine to reduce immune activation by altering Toll-like receptors function and expression, and canakinumab to block the action of a major pro-inflammatory cytokine IL-1β. Although many of the treatment strategies discussed here show promise, due to the complex nature of chronic inflammation and comorbidities in PWH, larger clinical studies are needed to understand and target the prominent drivers and inflammatory cascades underlying these end-organ diseases.

Prevention of Rat Intestinal Injury with a Drug Combination of Melatonin and Misoprostol

A healthy intestinal barrier prevents uptake of allergens and toxins, whereas intestinal permeability increases following chemotherapy and in many gastrointestinal and systemic diseases and disorders. Currently, there are no approved drugs that target and repair the intestinal epithelial barrier while there is a medical need for such treatment in gastrointestinal and related conditions. The objective of this single-pass intestinal perfusion study in rats was to investigate the preventive cytoprotective effect of three mucosal protective drugs—melatonin, misoprostol, and teduglutide—with different mechanisms of action on an acute jejunal injury induced by exposing the intestine for 15 min to the anionic surfactant, sodium dodecyl sulfate (SDS). The effect was evaluated by monitoring intestinal clearance of ⁵¹Cr-labeled ethylenediaminetetraacetate and intestinal histology before, during, and after luminal exposure to SDS. Our results showed that separate pharmacological pretreatments with luminal misoprostol and melatonin reduced acute SDS-induced intestinal injury by 47% and 58%, respectively, while their use in combination abolished this injury. This data supports further development of drug combinations for oral treatments of conditions and disorders related to a dysregulated or compromised mucosal epithelial barrier.

Site-Specific and Temporal Effects of Apraglutide, a Novel Long-Acting Glucagon-Like Peptide-2 Receptor Agonist, on Intestinal Growth in Mice

Long-acting glucagon-like peptide-2 receptor (GLP-2R) agonists are well-established to increase intestinal growth in rodents and, most notably, humans with short bowel syndrome. Most of the trophic effects of GLP-2R agonists are reported to be mediated through increased growth of the crypt-villus axis, resulting in enhanced mucosal mass and improved intestinal function. The present study examined the effects of apraglutide, a novel GLP-2R agonist, on the growth of the small intestine and colon after 3, 7, and 10 weeks of treatment in male and female mice. Apraglutide (3 mg/kg; three times per week) significantly increased small intestinal weight (P < 0.001) and length (P < 0.001) after 3 weeks of administration, with a further increase in effectiveness after 10 weeks (P < 0.01). Crypt depth and villus height were both markedly increased after 3 weeks of apraglutide administration (P < 0.001) but did not show any further increase with duration of treatment, whereas crypt number and intestinal circumference were increased after 7 and 10 weeks (P < 0.01) but not after 3 weeks of apraglutide treatment. Both the weight and the length of the colon were also enhanced by apraglutide treatment for 3 weeks (P < 0.001), and these effects were maintained but did not improve further with continued apraglutide administration. The results of this study demonstrate that the novel, long-acting GLP-2R agonist, apraglutide, demonstrates an unexpected marked ability to increase intestinal length as well as exert time- and location-dependent specificity in its intestinotrophic actions. SIGNIFICANCE STATEMENT: The novel long-acting glucagon-like peptide 2 receptor agonist, apraglutide, enhances intestinal weight as well as intestinal length in a time- and site-dependent fashion.

Pharmacological Characterization of Apraglutide, a Novel Long-Acting Peptidic Glucagon-Like Peptide-2 Agonist, for the Treatment of Short Bowel Syndrome

Glucagon-like peptide-2 (GLP-2) agonists have therapeutic potential in clinical indications in which the integrity or absorptive function of the intestinal mucosa is compromised, such as in short bowel syndrome (SBS). Native hGLP-2, a 33-amino acid peptide secreted from the small intestine, contributes to nutritional absorption but has a very short half-life because of enzymatic cleavage and renal clearance and thus is of limited therapeutic value. The GLP-2 analog teduglutide (Revestive/Gattex; Shire Inc.) has been approved for use in SBS since 2012 but has a once-daily injection regimen. Pharmacokinetic (PK) and pharmacodynamic studies confirm that apraglutide, a novel GLP-2 analog, has very low clearance, long elimination half-life, and high plasma protein binding compared with GLP-2 analogs teduglutide and glepaglutide. Apraglutide and teduglutide retain potency and selectivity at the GLP-2 receptor comparable to native hGLP-2, whereas glepaglutide was less potent and less selective. In rat intravenous PK studies, hGLP-2, teduglutide, glepaglutide, and apraglutide had clearances of 25, 9.9, 2.8, and 0.27 ml/kg per minute, respectively, and elimination half-lives of 6.4, 19, 16, and 159 minutes, respectively. The unique PK profile of apraglutide administered via intravenous and subcutaneous routes was confirmed in monkey and minipig and translated into significantly greater in vivo pharmacodynamic activity, measured as small intestinal growth in rats. Apraglutide showed greater intestinotrophic activity than the other peptides when administered at less-frequent dosing intervals because of its prolonged half-life. We postulate that apraglutide offers several advantages over existing GLP-2 analogs and is an excellent candidate for the treatment of gastrointestinal diseases, such as SBS. SIGNIFICANCE STATEMENT: Apraglutide is a potent and selective GLP-2 agonist with an extremely low clearance and prolonged elimination half-life, which differentiates it from teduglutide (the only approved GLP-2 agonist). The enhanced pharmacokinetics of apraglutide will benefit patients by enabling a reduced dosing frequency and removing the need for daily injections.

Free Fatty Acid Receptors as new potential therapeutic target in inflammatory bowel diseases

Family of Free Fatty Acid Receptors (FFARs), specific G protein-coupled receptors comprises of four members: FFAR1-4, where each responds to different chain length of fatty acids (FAs). Over the years, FFARs have become attractive pharmacological targets in the treatment of type 2 diabetes, metabolic syndrome, cardiovascular diseases and asthma; recent studies also point to their role in inflammation. It is now well-established that activation of FFAR1 and FFAR4 by long and medium chain FAs may lead to reduction of inflammatory state; FFAR2 and FFAR3 are activated by short chain FAs, but only FFAR2 was shown to alleviate inflammation, mostly by neutrophil inhibition. All FFARs have thus been proposed as targets in inflammatory bowel diseases (IBD). Here we discuss current knowledge and future directions in FFAR research related to IBD.

Glucagon-like peptide-2 mobilizes lipids from the intestine by a systemic nitric oxide-independent mechanism

AIM

To test the hypothesis that gut hormone glucagon-like peptide-2 (GLP-2) mobilizes intestinal triglyceride (TG) stores and stimulates chylomicron secretion by a nitric oxide (NO)-dependent mechanism in humans.

METHODS

In a randomized, single-blind, cross-over study, 10 healthy male volunteers ingested a high-fat formula followed, 7 hours later, by one of three treatments: NO synthase inhibitor L-N^G -monomethyl arginine acetate (L-NMMA) + GLP-2 analogue teduglutide, normal saline + teduglutide, or L-NMMA + placebo. TG in plasma and lipoprotein fractions were measured, along with measurement of blood flow in superior mesenteric and coeliac arteries using Doppler ultrasound in six participants.

RESULTS

Teduglutide rapidly increased mesenteric blood flow and TG concentrations in plasma, in TG-rich lipoproteins, and most robustly in chylomicrons. L-NMMA significantly attenuated teduglutide-induced enhancement of mesenteric blood flow but not TG mobilization and chylomicron secretion.

CONCLUSIONS

GLP-2 mobilization of TG stores and stimulation of chylomicron secretion from the small intestine appears to be independent of systemic NO in humans.

Recent Developments in Therapeutic Peptides for the Glucagon-like Peptide 1 and 2 Receptors

Glucagon-like peptide 1 (GLP-1) and glucagon-like peptide 2 (GLP-2) are proglucagon derived peptides that are released from gut endocrine cells in response to nutrient intake. These molecules are rapidly inactivated by the action of dipeptidyl peptidase IV (DPP-4) which limits their use as therapeutic agents. The recent emergence of three-dimensional structures of GPCRs such as GLP-1R and glucagon receptor has helped to drive the rational design of innovative peptide molecules that hold promise as novel peptide therapeutics. One emerging area is the discovery of multifunctional molecules that act at two or more pharmacological systems to enhance therapeutic efficacy. In addition, drug discovery efforts are also focusing on strategies to improve patient convenience through alternative routes of peptide delivery. These novel strategies highlight the broad utility of peptide-based therapeutics in human disease settings where unmet needs still exist.

Review article: the role of the autonomic nervous system in the pathogenesis and therapy of IBD

BACKGROUND

There is a growing body of evidence implicating a role for the brain-gut axis in the pathogenesis of inflammation in patients with IBD.

AIMS

To perform a narrative review of published literature regarding the association of the autonomic nervous system and intestinal inflammation and to describe the rationale for and emerging use of autonomic manipulation as a therapeutic agent METHODS: Current relevant literature was summarised and critically examined.

RESULTS

There is substantial pre-clinical and clinical evidence for a multifaceted anti-inflammatory effect of the vagus at both systemic and local intestinal levels. It acts via acetylcholine-mediated activation of α-7-acetylcholine receptors involving multiple cell types in innate and adaptive immunity and the enteric nervous system with subsequent protective influences on the intestinal barrier, inflammatory mechanisms and the microbiome. In patients with IBD, there is evidence for a sympatho-vagal imbalance, functional enteric neuronal depletion and hyporeactivity of the hypothalamic-pituitary-adrenal axis. Direct or transcutaneous vagal neuromodulation up-regulates the cholinergic anti-inflammatory pathway in pre-clinical and clinical models with down-regulation of systemic and local intestinal inflammation. This is supported by two small studies in Crohn's disease although remains to be investigated in ulcerative colitis.

CONCLUSIONS

Modulating the cholinergic anti-inflammatory pathway influences inflammation both systemically and at a local intestinal level. It represents a potentially underutilised anti-inflammatory therapeutic strategy. Given the likely pathogenic role of the autonomic nervous system in patients with IBD, vagal neuromodulation, an apparently safe and successful means of increasing vagal tone, warrants further clinical exploration.

Inflammatory Bowel Disease and Short Bowel Syndrome

Short bowel syndrome / intestinal failure (SBS/IF) is a rare and debilitating disease process that mandates a multidisciplinary approach in its management. Inflammatory bowel disease (IBD), in particular Crohn's disease (CD), predisposes patients to development of SBS/IF. This review discusses SBS/IF from the perspective of IBD, with an emphasis on prevention and treatment in the setting of CD. The aims of this review are to emphasize the unique treatment goals of the newly diagnosed SBS/IF patient, and highlight the role of both medical and surgical therapies in the management of IBD-related SBS/IF, including intestinal transplantation.

The roles of glucagon-like peptide-2 and the intestinal epithelial insulin-like growth factor-1 receptor in regulating microvillus length

Microvilli are tiny projections on the apical end of enterocytes, aiding in the digestion and absorption of nutrients. One of their key features is uniform length, but how this is regulated is poorly understood. Glucagon-like peptide-2 (GLP-2) has been shown to increase microvillus length but, the requirement of its downstream mediator, the intestinal epithelial insulin-like growth factor-1 receptor (IE-IGF-1R), and the microvillus proteins acted upon by GLP-2, remain unknown. Using IE-IGF-1R knockout (KO) mice, treated with either long-acting human (h) (GLY²)GLP-2 or vehicle for 11d, it was found that the h(GLY²)GLP-2-induced increase in microvillus length required the IE-IGF-1R. Furthermore, IE-IGF-1R KO alone resulted in a significant decrease in microvillus length. Examination of the brush border membrane proteome as well as of whole jejunal mucosa demonstrated that villin was increased with h(GLY²)GLP-2 treatment in an IE-IGF-1R-dependent manner. Under both basal conditions and with h(GLY²)GLP-2 treatment of the IE-IGF-1R KO mice, changes in villin, IRTKS-1, harmonin, β-actin, and myosin-1a did not explain the decrease in microvillus length, in either the brush border or jejunal mucosa of KO animals. Collectively, these studies define a new role for the IE-IGF-1R within the microvillus, in both the signaling cascade induced by GLP-2, as well as endogenously.

Role of glucagon-like peptides in inflammatory bowel diseases-current knowledge and future perspectives

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are chronic, relapsing, intestinal inflammatory disorders with complex and yet unrevealed pathogenesis in which genetic, immunological, and environmental factors play a role. Nowadays, a higher proportion of elderly IBD patients with coexisting conditions, such as cardiovascular disease and/or diabetes is recorded, who require more complex treatment and became a great challenge for gastroenterologists. Furthermore, some patients do not respond to anti-IBD therapy. These facts, together with increasing comorbidities in patients with IBD, imply that urgent, more complex, novel therapeutic strategies in the treatment are needed. Glucagon-like peptides (GLPs) possess numerous functions in the human body such as lowering blood glucose level, controlling body weight, inhibiting gastric emptying, reducing food ingestion, increasing crypt cell proliferation, and improving intestinal growth and nutrient absorption. Thus, GLPs and dipeptidyl peptidase IV (DPP-IV) inhibitors have recently gained attention in IBD research. Several animal models showed that treatment with GLPs may lead to improvement of colitis. This review presents data on the multitude effects of GLPs in the inflammatory intestinal diseases and summarizes the current knowledge on GLPs, which have the potential to become a novel therapeutic option in IBD therapy.

Off-Label Teduglutide Therapy in Non-intestinal Failure Patients with Chronic Malabsorption

BACKGROUND

Teduglutide, a glucagon-like peptide 2 analog, has demonstrated efficacy in treating adult patients with short bowel syndrome (SBS) and dependence on parenteral nutrition (PN), but its role in chronic malabsorptive states that do not necessitate PN remains uncertain.

AIMS

To evaluate teduglutide use beyond its approved indications and to discuss the results of this adjunctive treatment in patients resistant to established therapy.

RESULTS

This series reports four patients treated with teduglutide off-label. The first case had Crohn's disease (CD) with persistent colocutaneous fistulae that demonstrated complete closure after 8 months of teduglutide therapy. The second case involved a PN-dependent CD patient with persistent fistulae and intra-abdominal abscesses who weaned off PN and had a significant improvement in her nutritional status after 3 months of teduglutide therapy. The third case had CD complicated by severe malnutrition and previous PN-associated line infections, but by 9 months of teduglutide therapy, she gained 5 kg and no longer required re-initiation of PN. The fourth case had a high-output diverting ileostomy with resultant impaired healing of a stage IV decubitus ulcer, and after 2 months of therapy, the patient's pre-albumin increased by 250% and the ulcer had decreased by 40% in size.

CONCLUSION

The use of teduglutide might be broadened to include patients with functional SBS not meeting strict criteria for intestinal failure. Further studies should evaluate the efficacy of teduglutide in patients who may require short-term small intestine rehabilitation or who have chronically impaired absorptive capacity not yet requiring PN.

Systematic review: outcomes and adverse events from randomised trials in Crohn's disease

BACKGROUND

The suitability of disease activity indices has been challenged, with growing interest in objective measures of inflammation.

AIM

To undertake a systematic review of efficacy and safety outcomes in placebo-controlled randomised controlled trials (RCTs) of patients with Crohn's disease.

METHODS

MEDLINE, EMBASE, CINAHL and Cochrane Library were searched until November 2015, for RCTs of adult Crohn's disease patients treated with medical or surgical therapies. Data on efficacy and safety outcomes, end-point definitions, and measurement instruments were extracted and stratified by publication date (pre-2009 and 2009 onwards).

RESULTS

One hundred and eighty-one RCTs (110 induction and 71 maintenance) were identified, including 23 850 patients. About 92.3% reported clinical efficacy endpoints. The Crohn's Disease Activity Index (CDAI) dominated, defining clinical response or remission in 63.5% of trials (35 definitions of response or remission). CDAI < 150 was the commonest endpoint, but reporting reduced between periods (46.4%-41.1%), whilst use of CDAI100 increased (16.8%-30.4%). Fistula studies most commonly reported fistula closure (9, 90.0%). Reporting of biomarker, endoscopy and histology endpoints increased overall (33.3%-40.6%, 14.4%-30.4% and 3.2%-12.5%, respectively), but were heterogeneous and rarely reported in fistula trials. Patient-reported outcome measures were reported in 41.4% of trials and safety endpoints in 35.4%. Many of the common adverse events relate to disease exacerbation or treatment failure.

CONCLUSIONS

Trial endpoints vary across studies, over time and are distinct in fistula studies. Despite growth in reporting of objective measures of inflammation and in patient-reported outcome measures, there is a lack of standardisation. This confirms the need for a core outcome set for comparative effectiveness research in Crohn's disease.

Examining the pathophysiology of short bowel syndrome and glucagon-like peptide 2 analogue suitability in chronic intestinal failure: experience from a national intestinal failure unit

INTRODUCTION

Short bowel syndrome (SBS) is a leading cause of intestinal failure (IF). Home parenteral nutrition (HPN) remains the standard treatment, with small intestinal transplantation reserved for cases with severe complications to HPN. There have recently been significant developments in growth factor therapy. We aimed to develop a greater contemporary understanding of our SBS-IF subset.

METHOD

We performed a retrospective observational study of a prospectively maintained HPN audit database in October 2017. Intestinal anatomical details and parenteral requirements were recorded. Each case was assessed for eligibility for growth factor therapy using recently published trials.

RESULTS

Of 273 patients receiving HPN, 152 (55.7%) had type three IF as a result of SBS (SBS-IF), with a mean duration of HPN of 61 months (range 4-416). Mean length of small intestine was 98 cm. Furthermore, 114 (41.8%) patients had an end jejunostomy (SBS-J), 18 (6.6%) had an end ileostomy, and 7.3% of patients had all or part of the colon-in-continuity. Crohn's disease was the most common underlying pathology. Univariate analysis for the whole HPN cohort demonstrated SBS-IF and a longer duration of HPN to be associated with higher PN energy requirements, p ≤ 0.0001. Of all, 73 (48%) patients with SBS-IF were deemed suitable for GLP-2 analogue therapy, with co-morbidity being the most frequent cause of non-suitability (29.1%).

CONCLUSION

We describe a large U.K. HPN cohort using ESPEN pathophysiological and clinical severity classification. The majority of patients with SBS-IF had a jejunostomy and relatively few had colon-in-continuity. Co-morbidity is the most common contra-indication to GLP-2 analogue therapy.

CLINICAL RELEVANCY

GLP-2 analogues are emerging as an important treatment for patients with short bowel syndrome. Our study explores patient suitability in a large HPN cohort managed in a national IF centre. Furthermore, the international variation in the pathophysiology of SBS-IF varies significantly, which can have a bearing on PN requirements and outcomes when GLP-2 analogues are used.

Stapled, Long-Acting Glucagon-like Peptide 2 Analog with Efficacy in Dextran Sodium Sulfate Induced Mouse Colitis Models

Glucagon-like peptide 2 (GLP-2) is a hormone that has been shown to stimulate intestinal growth and attenuate intestinal inflammation. Despite being efficacious in a variety of animal models of disease, its therapeutic potential is hampered by the short half-life in vivo. We now describe a highly potent, stapled long-acting GLP-2 analog, peptide 10, that has a more than 10-fold longer half-life than teduglutide and improved intestinotrophic and anti-inflammatory effects in mouse models of DSS-induced colitis.

Glucagon like peptide-2 and neoplasia; a systematic review

Glucagon like peptide-2 is synthesized from enteroendocrine L cells primarily located in the ileum and large intestine. GLP-2 stimulates crypt cell proliferation, increases intestinal blood flow, enhances gut barrier function, induces mucosal healing, and exerts an anti-apoptotic effect. Due to these effects GLP-2 is used in the treatment of short bowel syndrome (SBS). Areas covered: The aim of this systematic review was to provide information on the potential risk of intestinal neoplasia in patients receiving treatment with GLP-2. The literature search was performed independently by two authors in the following databases; Pubmed, Embase, Scopus, Web of Science and Cochrane. Expert commentary: This systematic review indicated that treatment with GLP-2(1-33) up to 30 months in humans without any known pre-existing cancer did not confer an increased risk of intestinal neoplasia in patients or animals. However, due to the small amount of patients studied it is premature to reach any final conclusions about GLP-2 - induced neoplasia. GLP-2(1-33) treatment in animals with a pre-induced cancer showed that GLP-2(1-33) may promote growth of existing neoplasia.

Safety and Efficacy of Teduglutide (Gattex) in Patients With Crohn's Disease and Need for Parenteral Support Due to Short Bowel Syndrome-associated Intestinal Failure

BACKGROUND

Teduglutide is a GLP-2 analogue indicated for treatment of adults with short bowel syndrome (SBS). Because of the rarity of SBS, real-world safety or efficacy data are not available in patients with Crohn's disease (CD) and SBS treated with teduglutide.

AIM

To evaluate teduglutide's safety and efficacy in CD patients with SBS.

METHODS

We conducted a retrospective cohort study at 3 tertiary centers in the United States between 2012 and 2014. Demographic, clinical, and therapeutic data were retrieved from medical record systems.

RESULTS

Thirteen CD patients were included, 8 (62%) of whom were on concomitant immunosuppression. Median duration of teduglutide therapy was 365 days [interquartile range (IQR), 122 to 482 d] and 9/13 patients (69%) remain on therapy. At teduglutide initiation, 69% were on parenteral nutrition. At conclusion of follow-up, 1 patient was on parenteral nutrition. All patients were on intravenous fluids (IVF) before teduglutide; median IVF were 9000 mL/wk (IQR, 7000 to 14,000 mL/wk). IVF requirements decreased by a median of 3100 mL/wk (IQR, 2400 to 8400 mL/wk). Six patients (46%) ceased IVF. Adverse events attributed to teduglutide were obstructive symptoms (n=1), pancreatitis (n=1), asymptomatic lipase and amylase elevation (n=1), nausea (n=1), and abdominal pain (n=1). Catheter-related sepsis occurred in 4 patients.

CONCLUSIONS

This is the first report evaluating the safety and efficacy of teduglutide in a cohort of CD patients with SBS requiring parenteral support. More of half the cohort was on concomitant immunosuppression. Teduglutide seemed to be safe and the majority of patients were weaned off parenteral support.

Integrated Neural and Endocrine Control of Gastrointestinal Function

The activity of the digestive system is dynamically regulated by external factors, including body nutritional and activity states, emotions and the contents of the digestive tube. The gut must adjust its activity to assimilate a hugely variable mixture that is ingested, particularly in an omnivore such as human for which a wide range of food choices exist. It must also guard against toxins and pathogens. These nutritive and non-nutritive components of the gut contents interact with the largest and most vulnerable surface in the body, the lining of the gastrointestinal tract. This requires a gut sensory system that can detect many classes of nutrients, non-nutrient components of food, physicochemical conditions, toxins, pathogens and symbionts (Furness et al., Nat Rev Gastroenterol Hepatol 10:729-740, 2013). The gut sensors are in turn coupled to effector systems that can respond to the sensory information. The responses are exerted through enteroendocrine cells (EEC), the enteric nervous system (ENS), the central nervous system (CNS) and the gut immune and tissue defence systems. It is apparent that the control of the digestive organs is an integrated function of these effectors. The peripheral components of the EEC, ENS and CNS triumvirate are extensive. EEC cells have traditionally been classified into about 12 types (disputed in this review), releasing about 20 hormones, together making the gut endocrine system the largest endocrine organ in the body. Likewise, in human the ENS contains about 500 million neurons, far more than the number of neurons in the remainder of the peripheral autonomic nervous system. Together gut hormones, the ENS and the CNS control or influence functions including satiety, mixing and propulsive activity, release of digestive enzymes, induction of nutrient transporters, fluid transport, local blood flow, gastric acid secretion, evacuation and immune responses. Gut content receptors, including taste, free fatty acid, peptide and phytochemical receptors, are primarily located on EEC. Hormones released by EEC act via both the ENS and CNS to optimise digestion. Toxic chemicals and pathogens are sensed and then avoided, expelled or metabolised. These defensive activities also involve the EEC and signalling from EEC to the ENS and the CNS. A major challenge is to develop a comprehensive understanding of the integrated responses of the gut, via its effector systems, the ENS, extrinsic innervation, EEC and the gut immune system, to the sensory information it receives.

Irinotecan-induced mucositis: the interactions and potential role of GLP-2 analogues

PURPOSE

A common side effect of irinotecan administration is gastrointestinal mucositis, often manifesting as severe diarrhoea. The damage to the structure and function of the gastrointestinal tract caused by this cytotoxic agent is debilitating and often leads to alterations in patients' regimens, hospitalisation or stoppage of treatment. The purpose of this review is to identify mechanisms of irinotecan-induced intestinal damage and a potential role for GLP-2 analogues for intervention.

METHODS

This is a review of current literature on irinotecan-induced mucositis and GLP-2 analogues mechanisms of action.

RESULTS

Recent studies have found alterations that appear to be crucial in the development of severe intestinal mucositis, including early apoptosis, alterations in proliferation and cell survival pathways, as well as induction of inflammatory cascades. Several studies have indicated a possible role for glucagon-like peptide-2 analogues in treating this toxicity, due to its proven intestinotrophic, anti-apoptotic and anti-inflammatory effects in other models of gastrointestinal disease.

CONCLUSION

This review provides evidence as to why and how this treatment may improve mucositis through the possible molecular crosstalk that may be occurring in models of severe intestinal mucositis.

Rate and Predictors of Endoscopic Mucosal Healing in Biologic Naive Patients with Inflammatory Bowel Disease by Azathioprine Treatment: A Real World, 10 Years' Experience from a Single Centre in Turkey

BACKGROUND

There is increasing evidence that endoscopic mucosal healing (EMH) is a key target in inflammatory bowel disease (IBD) therapy. However, there is limited evidence of EMH rates with conventional IBD therapy outside of Western population groups.

AİM

To evaluate the role of azathioprine (AZA) in inducing EMH in IBD patients.

METHODS

Patients with inflammatory bowel disease were evaluated in terms of endoscopic mucosal healing and the incidence of surgical interventions during the azathioprine treatment between 1995 to 2014.

RESULTS

A total of 120 inflammatory bowel disease patients were enrolled. Endoscopic mucosal healing was found in 37% patients with inflammatory bowel disease (42% in chronic ulcerative colitis and 33% in Crohn's disease). Male gender had a negative impact on the efficacy of azathioprine (P<0.05). Responder inflammatory bowel disease patients were older (age at the IBD diagnose) than the nonresponder (P<0.05). Azathioprine therapy reduced the number of the surgical interventions (P<0.05).

CONCLUSİON

We showed that azathioprine therapy significantly induced endoscopic mucosal healing in biologic naïve patients with active inflammatory bowel disease as well as decreasing the surgical interventions, with negative predictive factors identified by a younger age at IBD presentation and male gender.

Current and potential therapeutic targets of glucagon-like peptide-2

Glucagon-like peptide-2 (GLP-2) is a gut hormone that promotes highly specific growth and function of the intestinal epithelium. Recent studies have begun to elucidate the complex mechanism of action of GLP-2, which is mediated indirectly through other intestinal factors. Although a long-acting GLP-2 analog has recently been approved for treatment of adult patients with short bowel syndrome, there remain numerous conditions characterized by intestinal insufficiency for which pre-clinical studies, as well as some limited clinical data, support further consideration of GLP-2 for expanded therapeutic use.

The intestinal microbiome, barrier function, and immune system in inflammatory bowel disease: a tripartite pathophysiological circuit with implications for new therapeutic directions

We discuss the tripartite pathophysiological circuit of inflammatory bowel disease (IBD), involving the intestinal microbiota, barrier function, and immune system. Dysfunction in each of these physiological components (dysbiosis, leaky gut, and inflammation) contributes in a mutually interdependent manner to IBD onset and exacerbation. Genetic and environmental risk factors lead to disruption of gut homeostasis: genetic risks predominantly affect the immune system, environmental risks predominantly affect the microbiota, and both affect barrier function. Multiple genetic and environmental 'hits' are likely necessary to establish and exacerbate disease. Most conventional IBD therapies currently target only one component of the pathophysiological circuit, inflammation; however, many patients with IBD do not respond to immune-modulating therapies. Hope lies in new classes of therapies that target the microbiota and barrier function.

Inflammation Meets Metabolic Disease: Gut Feeling Mediated by GLP-1

Chronic diseases, such as obesity and diabetes, cardiovascular, and inflammatory bowel diseases (IBD) share common features in their pathology. Metabolic disorders exhibit strong inflammatory underpinnings and vice versa, inflammation is associated with metabolic alterations. Next to cytokines and cellular stress pathways, such as the unfolded protein response (UPR), alterations in the enteroendocrine system are intersections of various pathologies. Enteroendocrine cells (EEC) have been studied extensively for their ability to regulate gastrointestinal motility, secretion, and insulin release by release of peptide hormones. In particular, the L-cell-derived incretin hormone glucagon-like peptide 1 (GLP-1) has gained enormous attention due to its insulinotropic action and relevance in the treatment of type 2 diabetes (T2D). Yet, accumulating data indicate a critical role for EEC and in particular for GLP-1 in metabolic adaptation and in orchestrating immune responses beyond blood glucose control. EEC sense the lamina propria and luminal environment, including the microbiota via receptors and transporters. Subsequently, mediating signals by secreting hormones and cytokines, EEC can be considered as integrators of metabolic and inflammatory signaling. This review focuses on L cell and GLP-1 functions in the context of metabolic and inflammatory diseases. The effects of incretin-based therapies on metabolism and immune system are discussed and the interrelation and common features of metabolic and immune-mediated disorders are highlighted. Moreover, it presents data on the impact of inflammation, in particular of IBD on EEC and discusses the potential role of the microbiota as link between nutrients, metabolism, immunity, and disease.