Review article: an analysis of safety profiles of treatments for diarrhoea-predominant irritable bowel syndrome

Chang-Kang-Fang alleviates diarrhea predominant irritable bowel syndrome (IBS-D) through inhibiting TLR4/NF-κB/NLRP3 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Chang-Kang-Fang (CKF), originated from traditional Chinese medicine (TCM) formulas, has been utilized to treat diarrhea predominant irritable bowel syndrome (IBS-D) based on clinical experience. However, the underlying mechanism of CKF for treating IBS-D remains unclear and need further clarification.

AIM OF THE STUDY

The objective of this present investigation was to validate the efficacy of CKF on IBS-D model rats and to uncover its potential mechanism for the treatment of IBS-D.

MATERIALS AND METHODS

We first established the IBS-D rat model through neonatal maternal separation (NMS) in combination with restraint stress (RS) and the administration of senna decoction via gavage. To confirm the therapeutic effect of CKF on treating IBS-D, abdominal withdrawal reflex (AWR) scores, the quantity of fecal pellets, and the fecal water content (FWC) were measured to evaluate the influence of CKF on visceral hypersensitivity and the severity of diarrhea symptom after the intragastric administration of CKF for 14 days. Subsequently, enzyme linked immunosorbent assay (ELISA) was applied to assess the effect of CKF on neuropeptides substance P (SP) and 5-hydroxytryptamine (5-HT), as well as inflammatory cytokines in serum and in intestinal tissues. Further, colonic pathological changes, the amount of colonic mast cells, and the expression level of occludin in rat colon tissues, were investigated by hematoxylin-eosin (HE) staining, toluidine blue staining, and immunohistochemistry, respectively. To explore the underlying mechanisms, alterations in colonic RNA transcriptomics for the normal, model, and CKF treatment groups were assessed using RNA sequencing (RNA-Seq). Subsequently, quantitative real-time polymerase chain reaction (qRT-PCR), Western blot (WB), and immunofluorescence (IF) assays were applied to validate the effect of CKF on predicted pathways in vivo and in vitro. In addition, to elucidate the potential active compounds in CKF, 11 representative components found in CKF were selected, and their anti-inflammation potentials were evaluated using LPS-treated RAW264.7 cell models.

RESULTS

CKF treatment significantly reduced the number of fecal pellets, attenuated visceral hypersensitivity, and decreased 5-HT and SP concentrations in serum and colon tissues, along with a reduction in colonic mast cell counts, correlating with improved symptoms in IBS-D rats. Meanwhile, CKF treatment reduced the colonic inflammatory cell infiltration, lowered the levels of IL-6, TNF-α, and IL-1β in serum and colon tissues, and increased the occludin protein expression in colon tissues to improve inflammatory response and colonic barrier function. RNA-Seq, in conjugation with our previous network pharmacology analysis, indicated that CKF might mitigate the symptoms of IBS-D rats by inhibiting the Toll like receptor 4/Nuclear factor kappa-B/NLR family pyrin domain-containing protein 3 (TLR4/NF-κB/NLRP3) pathway, which was confirmed by WB, IF, and qRT-PCR experiments in vivo and in vitro. Furthermore, coptisine, berberine, hyperoside, epicatechin, and gallic acid present in CKF emerged as potential active components for treating IBS-D, as they demonstrated in vitro anti-inflammatory effects.

CONCLUSION

Our findings demonstrate that CKF effectively improves the symptoms of IBS-D rats, potentially through the inhibition of the TLR4/NF-κB/NLRP3 pathway. Moreover, this study unveils the potential bioactive components in CKF that could be applied in the treatment of IBS-D.

Probiotic Yeast from Miso Ameliorates Stress-Induced Visceral Hypersensitivity by Modulating the Gut Microbiota in a Rat Model of Irritable Bowel Syndrome

Background/Aims

Recent studies indicate that probiotics, which have attracted attention as a treatment for irritable bowel syndrome, affect intestinal homeostasis. In this study, we investigated whether Zygosaccharomyces sapae (strain I-6), a probiotic yeast isolated from miso (a traditional Japanese fermented food), could improve irritable bowel syndrome symptoms.

Methods

Male Wistar rats were exposed to water avoidance stress (WAS). The number of defecations during WAS and the visceral hypersensitivity before and after WAS were evaluated using colorectal distension. Tight junction changes were assessed by Western blotting. Some rats were fed with strain I-6 or β-glucan from strain I-6. Changes in the intestinal microbiota were analyzed. The effect of fecal microbiota transplantation after WAS was evaluated similarly. Caco-2 cells were stimulated with interleukin-1β and tight junction changes were investigated after coculture with strain I-6.

Results

The increased number of stool pellets and visceral hypersensitivity induced by WAS were suppressed by administering strain I-6. The decrease in tight junction protein occludin by WAS was reversed by the administration of strain I-6. β-Glucan from strain I-6 also suppressed those changes induced by WAS. In the rat intestinal microbiota, treatment with strain I-6 altered the β-diversity and induced changes in bacterial occupancy. Upon fecal microbiota transplantation, some symptoms caused by WAS were ameliorated.

Conclusions

These results suggest that traditional fermented foods such as miso in Japan are valuable sources of probiotic yeast candidates, which may be useful for preventing and treating stress-induced visceral hypersensitivity.

Pharmacokinetic considerations for drugs that treat diarrhea-predominant irritable bowel syndrome: what's new?

INTRODUCTION

Irritable bowel syndrome (IBS), which presents a significant healthcare and socioeconomic burden, is one of the main issues in the field of therapy. Hence, it is imperative to tackle this matter by evaluating the safety and efficacy of the available treatments and determining the ideal approach for each patient.

AREAS COVERED

We reviewed the pharmacokinetics and safety of pharmacologic interventions administered in diarrhea-predominant IBS (IBS-D) patients. PubMed, Google Scholar and the USFDA databases were searched up to November 2023 to include all updated information on eluxadoline, alosetron, and rifaximin.

EXPERT OPINION

The most effective way to treat IBS-D is to focus on managing the most common symptoms. However, healthcare providers face a challenge when it comes to identifying the right treatment for each patient, and the root cause of this is the diversity of IBS-D population. Studies have shown that there are differences in how men and women metabolize drugs, which may lead to gender-specific adverse reactions. Women tend to have higher drug concentrations in their bloodstream and take longer to eliminate them. Therefore, healthcare providers may need to reduce the dosage for female patients. Integrating IBS care into sustainable development efforts can indirectly contribute to achieving SDGs and promote health and well-being for all.

Most patients with disorders of gut-brain interaction receive pharmacotherapy with major or moderate drug-gene interactions

BACKGROUND

How variations predicted by pharmacogenomic testing to alter drug metabolism and therapeutic response affect outcomes for patients with disorders of gut- brain interaction is unclear.

AIMS

To assess the prevalence of pharmacogenomics-predicted drug-gene interactions and symptom outcomes for patients with disorders of gut-brain interaction.

METHODS

Patients who were treated in our clinical practice for functional dyspepsia/bowel disorder underwent pharmacogenomic testing. The change in symptoms from baseline to 6 months was compared for patients with variations in CYP2D6 and CYP2C19, which metabolize neuromodulators, and SLC6A4, which encodes the sodium- dependent serotonin transporter.

RESULTS

At baseline, 79 of 94 participants (84%) had at least one predicted major drug- gene interaction, and all 94 (100%) had at least one predicted moderate interaction. For the 44 participants who completed a survey of their symptoms at 6 months, the mean (SD) irritable bowel syndrome-symptom severity score decreased from 284 (71) at baseline to 231 (95) at 6 months (p < 0.001). Among patients taking selective serotonin reuptake inhibitors, the decrease in symptom severity (p = 0.03) and pain (p = 0.002) scores from baseline to 6 months was greater for patients with a homozygous SLC6A4 long/long genotype (n = 30) (ie, increased serotonin transporter activity) than for patients with homozygous short/short or heterozygous long/short genotypes (n = 64). Symptom outcomes were not affected by CYP2D6 or CYP2C19 variations.

CONCLUSIONS

The homozygous SLC6A4 long/long genotype confers better symptom resolution for patients with disorders of gut-brain interaction who take selective serotonin reuptake inhibitors than do the homozygous short/short or heterozygous long/short genotypes.

Opioid-Induced Pronociceptive Signaling in the Gastrointestinal Tract Is Mediated by Delta-Opioid Receptor Signaling

Opioid tolerance (OT) leads to dose escalation and serious side effects, including opioid-induced hyperalgesia (OIH). We sought to better understand the mechanisms underlying this event in the gastrointestinal tract. Chronic in vivo administration of morphine by intraperitoneal injection in male C57BL/6 mice evoked tolerance and evidence of OIH in an assay of colonic afferent nerve mechanosensitivity; this was inhibited by the δ-opioid receptor (DOPr) antagonist naltrindole when intraperitoneally injected in previous morphine administration. Patch-clamp studies of DRG neurons following overnight incubation with high concentrations of morphine, the µ-opioid receptors (MOPr) agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-Enkephalin (DAMGO) or the DOPr agonist [D-Ala2, D-Leu5]-Enkephalin evoked hyperexcitability. The pronociceptive actions of these opioids were blocked by the DOPr antagonist SDM25N but not the MOPr antagonist D-Pen-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 The hyperexcitability induced by DAMGO was reversed after a 1 h washout, but reapplication of low concentrations of DAMGO or [D-Ala2, D-Leu5]-Enkephalin restored the hyperexcitability, an effect mediated by protein kinase C. DOPr-dependent DRG neuron hyperexcitability was blocked by the endocytosis inhibitor Pitstop 2, and the weakly internalizing DOPr agonist ARM390 did not cause hyperexcitability. Bioluminescence resonance energy transfer studies in HEK cells showed no evidence of switching of G-protein signaling from Gi to a Gs pathway in response to either high concentrations or overnight incubation of opioids. Thus, chronic high-dose opioid exposure leads to opioid tolerance and features of OIH in the colon. This action is mediated by DOPr signaling and is dependent on receptor endocytosis and downstream protein kinase C signaling.SIGNIFICANCE STATEMENT Opioids are effective in the treatment of abdominal pain, but escalating doses can lead to opioid tolerance and potentially opioid-induced hyperalgesia. We found that δ-opioid receptor (DOPr) plays a central role in the development of opioid tolerance and opioid-induced hyperalgesia in colonic afferent nociceptors following prolonged exposure to high concentrations of MOPr or DOPr agonists. Furthermore, the role of DOPr was dependent on OPr internalization and activation of a protein kinase C signaling pathway. Thus, targeting DOPr or key components of the downstream signaling pathway could mitigate adverse side effects by opioids.

Bile acid-gut microbiota crosstalk in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction with an increasing prevalence, and its precise aetiology remains unclear. Gut microbiota dysbiosis has been found to be associated with IBS pathogenesis. In addition, a high incidence of bile acid diarrhoea and disturbed bile acid metabolism has been observed in IBS patients. The abundant microorganisms inhabited in human gut have essential functions in bile acid biotransformation, and can immensely affect the size and constitution of bile acid pool. Meanwhile, the alterations of bile acid profile can inversely interfere with the gut microbiota. This review discussed the role of intricate correlations between bile acids and gut microbiota in IBS pathogenesis and delineated the possible molecular mechanisms, mainly the signalling induced by farnesoid X receptor and transmembrane G protein-coupled receptor 5. Besides, some biomarkers for identifying bile acid diarrhoea in IBS population were listed, assisting the diagnosis and classification of IBS. Moreover, it also assessed some therapeutic strategies for IBS that regulate the bile acid-gut microbiota axis, such as dietary modulation, probiotics/prebiotics, faecal microbiota transplantation, and antibiotics. Collectively, this article illustrated the relationship between bile acids and gut microbiota in IBS pathophysiology and might offer some novel therapeutic options for IBS.

Performance of a multi-compounds nutraceutical formulation in patients with symptomatic uncomplicated diverticular disease

BACKGROUND

Symptomatic uncomplicated diverticular disease (SUDD) is a recognized clinical condition characterized by abdominal pain and changes in bowel habits, attributed to diverticula but without macroscopic signs of diverticulitis. There is no consensus about the management of these patients. Enteroflegin®, an association of natural active ingredients, could be effective in the treatment of those patients.

METHODS

We conducted a retrospective observational study to evaluate the performances of Enteroflegin® in patients with SUDD. Patients were treated with Enteroflegin® 2 cp/day for 10 days per month for 6 months. Primary endpoint was the clinical remission rate, defined as the absence of any symptoms; secondary endpoints were the impact of the treatment on reduction of symptoms, on fecal calprotectin (FC) expression, and the prevention of acute diverticulitis.

RESULTS

Three hundred and fifty patients were retrospectively enrolled (183 males, median age 64 yrs, IQR 54-70). Enteroflegin® was effective in inducing remission in 9.34% and 17.64% of patients at 3 and 6 months respectively (p<0.001). Reduction of symptoms occurred in 92.3% and in 85.3% of patients at 3 and 6 months respectively (p<0.001), and symptoms' recurrence or worsening was recorded in only 1.71% of patients during the follow-up. FC expression dropped from 181,3 μg/g at baseline to 100,2 μg/g (p<0.001) and to 67,9 μg/g (p<0.001) at 3 and 6 months of follow-up respectively. No adverse event was recorded during the follow-up. Finally, acute diverticulitis occurred in just 2% of patients during the follow-up.

CONCLUSIONS

Enteroflegin® seems to be an effective nutraceutical compound in obtaining remission and symptom relief in SUDD patients. Further randomized, placebo-controlled clinical trials are needed to confirm these preliminary data.

Moxibustion for diarrhea in COVID-19: A protocol for systematic review and meta-analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) is an acute respiratory infectious disease that is often accompanied by diarrhea, patients with symptoms such as diarrhea are more likely to develop severe pneumonia, while diarrhea is the most prominent among atypical symptoms. The incidence of diarrhea in COVID-19 patients is 2.0% to 49.5%. Moxibustion has been proven to have a therapeutic effect on diarrhea; however, there is no high-quality evidence on moxibustion for diarrhea in COVID-19 patients. This study was designed to evaluate the effectiveness and safety of moxibustion for the treatment of diarrhea in patients with COVID-19.

METHODS

Randomized controlled trials from December 2019 to December 2021 will be included without restrictions on language or publication date. PubMed, EMBASE, Cochrane Library, Web of Science, Chinese Biomedical Databases, China National Knowledge Infrastructure, Wanfang database, and VIP database will be searched. Two researchers will independently select studies, extract data and evaluate study quality. Cochrane risk of bias tool for randomized trials will be used to assess the risk of bias of included studies. Statistical analyses will be performed using the Review Manager V.5.3 and stata 14.0.

RESULTS

The results of this meta-analysis will be submitted to a peer-reviewed journal for publication.

CONCLUSION

This study will provide evidence for whether moxibustion therapy is beneficial to the treatment of diarrhea in COVID-19.

ETHICS AND DISSEMINATION

Ethical approval is not required for this study. The systematic review will be published in a peer-reviewed journal, presented at conferences, and shared on social media platforms. This review would be disseminated in a peer-reviewed journal or conference presentations.

PROSPERO REGISTRATION NUMBER

CRD42022302933.

Moxibustion for diarrhea-predominant irritable bowel syndrome: A protocol for systematic review and network meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is commonly accompanied by intestinal dysfunction, and diarrhea-predominant irritable bowel syndrome accounts for approximately 23.4% of all cases of IBS. The purpose of this study was to evaluate the efficacy and safety of moxibustion in the treatment of diarrhea-predominant irritable bowel syndrome.

METHODS

According to the retrieval strategies, randomized controlled trials (RCTs) on moxibustion therapies for IBS-D will be obtained from the China National Knowledge Infrastructure, WanFang Data, Chinese Scientific Journals Database, PubMed, Embase, and Cochrane Library, regardless of publication date or language. Studies will be screened based on inclusion and exclusion criteria, and the Cochrane risk bias assessment tool will be used to evaluate the quality of the literature. The network meta-analysis will be performed with the Markov chain Monte Carlo method and carried out with Stata 14.2 and WinBUGS 1.4.3 software. Ultimately, the quality of the evidence obtained from the results will be evaluated.

RESULTS

This study will evaluate whether moxibustion therapy can effectively treat diarrhea-predominant irritable bowel syndrome.

CONCLUSION

This study will provide evidence for whether moxibustion therapy is beneficial to the treatment of human diarrhea-predominant irritable bowel syndrome.

INPLASY REGISTRATION NUMBER

INPLASY202180003.

Moxibustion for diarrhea-predominant irritable bowel syndrome: A protocol for systematic review and network meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is commonly accompanied by intestinal dysfunction, and diarrhea-predominant irritable bowel syndrome accounts for approximately 23.4% of all cases of IBS. The purpose of this study was to evaluate the efficacy and safety of moxibustion in the treatment of diarrhea-predominant irritable bowel syndrome.

METHODS

According to the retrieval strategies, randomized controlled trials (RCTs) on moxibustion therapies for IBS-D will be obtained from the China National Knowledge Infrastructure, WanFang Data, Chinese Scientific Journals Database, PubMed, Embase, and Cochrane Library, regardless of publication date or language. Studies will be screened based on inclusion and exclusion criteria, and the Cochrane risk bias assessment tool will be used to evaluate the quality of the literature. The network meta-analysis will be performed with the Markov chain Monte Carlo method and carried out with Stata 14.2 and WinBUGS 1.4.3 software. Ultimately, the quality of the evidence obtained from the results will be evaluated.

RESULTS

This study will evaluate whether moxibustion therapy can effectively treat diarrhea-predominant irritable bowel syndrome.

CONCLUSION

This study will provide evidence for whether moxibustion therapy is beneficial to the treatment of human diarrhea-predominant irritable bowel syndrome.

INPLASY REGISTRATION NUMBER

INPLASY202180003.

A survey of gastroenterologists in the United States on the use of central neuromodulators for treating irritable bowel syndrome

BACKGROUND

Central neuromodulators are an effective treatment for irritable bowel syndrome (IBS) but may be used less frequently than other therapies.

AIMS

To survey gastroenterologists in the United States (US) about their use of neuromodulators in patients with IBS.

METHODS

A 23-question survey was distributed to gastroenterologists in the United States. Comparisons in prescribing practices were conducted between (a) gastroenterologists who were "high prescribers" versus "low prescribers" of neuromodulators in patients with IBS and (b) gastroenterologists and "gastroenterology experts" in the use of neuromodulators using descriptive statistics and multivariable logistic regression analyses.

RESULTS

The 525 gastroenterologists who were surveyed used neuromodulators for a median range of 21%-30% of their patients with IBS. Neuromodulators were described as extremely/very important in managing IBS by 55% of clinicians. Significant predictors of high-prescribing behaviour were academic versus clinical practice setting (odds ratio [OR] 2.60 [95% CI 1.61-4.20]), disorders of brain-gut interaction focused practice (OR 4.80 [2.60-8.84]), and greater perceived effectiveness of neuromodulators (OR 2.75 [1.30-5.84]). Compared to gastroenterologists, experts prescribed neuromodulators to a higher percentage of their patients with IBS (41%-50% vs 21%-30%; P = 0.019) and more frequently found neuromodulators effective (70% vs 27%; P = 0.003). However, concern about side effects was the most common barrier to neuromodulator use (59%).

CONCLUSIONS

The majority of US gastroenterologists believe central neuromodulators are important in treating IBS, and 27% believe they are effective in most patients. High prescribers are in academic practice, focus in IBS and perceive central neuromodulators as effective. Education is needed to improve gastroenterologists' prescribing behaviour.

Probiotics, Prebiotics, and Synbiotics: Implications and Beneficial Effects against Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is still a common functional gastrointestinal disease that presents chronic abdominal symptoms but with a pathophysiology that is not yet fully elucidated. Moreover, the use of the synergistic combination of prebiotics and probiotics, known as synbiotics, for IBS therapy is still in the early stages. Advancements in technology led to determining the important role played by probiotics in IBS, whereas the present paper focuses on the detailed review of the various pathophysiologic mechanisms of action of probiotics, prebiotics, and synbiotics via multidisciplinary domains involving the gastroenterology (microbiota modulation, alteration of gut barrier function, visceral hypersensitivity, and gastrointestinal dysmotility) immunology (intestinal immunological modulation), and neurology (microbiota–gut–brain axis communication and co-morbidities) in mitigating the symptoms of IBS. In addition, this review synthesizes literature about the mechanisms involved in the beneficial effects of prebiotics and synbiotics for patients with IBS, discussing clinical studies testing the efficiency and outcomes of synbiotics used as therapy for IBS.

Management of irritable bowel syndrome with diarrhea: focus on eluxadoline

OBJECTIVE

We sought to summarize current recommendations for the diagnosis of diarrhea-predominant irritable bowel syndrome (IBS-D) and describe available management options, highlighting a newer US Food and Drug Administration (FDA)-approved agent, eluxadoline.

METHODS

Literature on IBS-D was assessed up to January 2020 using PubMed, with key search terms including "IBS-D diagnosis", "IBS-D management", and "eluxadoline".

RESULTS

IBS is a common gastrointestinal disorder affecting up to 14% of US adults and is particularly prevalent in women and those aged under 50. Symptoms include abdominal pain associated with altered bowel habits (i.e. diarrhea and/or constipation subtyped based on the predominant stool pattern). As IBS-D is challenging to manage with varying symptom severity, effective treatment requires a personalized management approach. Evidence-based therapeutic options endorsed by the American Gastroenterological Association and the American College of Gastroenterology can be used to effectively guide treatment. Dietary and lifestyle modifications, including adequate hydration, reducing caffeine and alcohol intake, and increasing soluble fiber intake may lead to symptom improvement. Over-the-counter medications such as loperamide are frequently recommended and may improve stool frequency and rectal urgency; however, for the outcome of abdominal pain, mixed results have been observed. Several off-label prescription medications are useful in IBS-D management, including tricyclic antidepressants, bile acid sequestrants, and antispasmodics. Three prescription medications have been approved by the FDA for IBS-D: alosetron, eluxadoline, and rifaximin.

CONCLUSIONS

IBS-D can be effectively managed in the primary care setting in the absence of alarm features. Benefits and risks of pharmacologic interventions should be weighed during treatment selection.

Patients With Irritable Bowel Syndrome Are Willing to Take Substantial Medication Risks for Symptom Relief

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is a common chronic functional bowel disorder for which patients take significant risks to ameliorate symptoms. Unfortunately, there is no cure for IBS. We assessed the willingness of patients with IBS to take medication risks and the costs they would pay to improve symptoms.

METHODS

We mailed a survey on medication risk to patients with IBS who met the Rome IV criteria. The survey collected data on patient demographics, symptoms, medication use, prior medication-averse events, and pain catastrophization. A standard gamble evaluated respondents' willingness to take medication risks, and a willingness-to-pay set of questions quantified maximal spending on a hypothetical medication to treat IBS.

RESULTS

Among respondents (n = 215; 81.8% female; mean age, 57 y) the average duration of IBS symptoms was 17.7 years. Patients whose predominant symptom was severe diarrhea (diarrhea-predominant IBS) reported accepting a mean 10.2% ± 15.7% risk of sudden death for a 99% chance of cure. Pain catastrophizing scale scores were not associated with an increased likelihood of taking medication risks. Patients with IBS would be willing to pay an average amount of $73 per month (if annual income was <$75,000) and $197 per month (if annual income was >$75,000) for a medication that would resolve their pain.

CONCLUSIONS

In a survey of 215 patients with IBS, we found that patients with diarrhea-predominant IBS are willing to take extraordinary risks to improve their symptoms, whereas patients with IBS and pain catastrophization are not. Clinician understanding of patients' willingness to take medication risks might help them guide their patients through complex therapeutic options.

ACG Clinical Guideline: Management of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a highly prevalent, chronic disorder that significantly reduces patients' quality of life. Advances in diagnostic testing and in therapeutic options for patients with IBS led to the development of this first-ever American College of Gastroenterology clinical guideline for the management of IBS using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Twenty-five clinically important questions were assessed after a comprehensive literature search; 9 questions focused on diagnostic testing; 16 questions focused on therapeutic options. Consensus was obtained using a modified Delphi approach, and based on GRADE methodology, we endorse the following: We suggest that a positive diagnostic strategy as compared to a diagnostic strategy of exclusion be used to improve time to initiating appropriate therapy. We suggest that serologic testing be performed to rule out celiac disease in patients with IBS and diarrhea symptoms. We suggest that fecal calprotectin be checked in patients with suspected IBS and diarrhea symptoms to rule out inflammatory bowel disease. We recommend a limited trial of a low fermentable oligosaccharides, disacchardies, monosaccharides, polyols (FODMAP) diet in patients with IBS to improve global symptoms. We recommend the use of chloride channel activators and guanylate cyclase activators to treat global IBS with constipation symptoms. We recommend the use of rifaximin to treat global IBS with diarrhea symptoms. We suggest that gut-directed psychotherapy be used to treat global IBS symptoms. Additional statements and information regarding diagnostic strategies, specific drugs, doses, and duration of therapy can be found in the guideline.

When to use probiotics in luminal gastrointestinal disorders?

PURPOSE OF REVIEW

With the growing popularity and commercialization of probiotics, it is important to understand the implications of existing randomized controlled trials and their applicability in the clinical setting to treat luminal gastrointestinal diseases.

RECENT FINDINGS

Probiotics may be useful in the prevention of antibiotic-associated diarrhea, prevention of Clostridioides difficile infection and eradication of Helicobacter pylori. Some evidence supports the use of probiotics in the treatment of ulcerative colitis, prevention and treatment of pouchitis and irritable bowel syndrome. Caution has to be exercised in immunocompromised and critically ill individuals. New society guidelines do not encourage probiotic use in gastrointestinal disorders with the exception of premature infants to prevent necrotizing enterocolitis.

SUMMARY

Despite burgeoning body of literature and wide acceptance by the public, a thorough understanding of efficacy and safety of probiotics is lacking. Uniform dosage, standardized clinical end points, personalization based on host microbial profile and longer duration of follow-up on the research front may help in the future in appropriate positioning of probiotics in health and disease.

Effect of mild moxibustion on intestinal microbiota and NLRP6 inflammasome signaling in rats with post-inflammatory irritable bowel syndrome

BACKGROUND

About one-third of refractory irritable bowel syndrome (IBS) cases are caused by gastrointestinal (GI) infection/inflammation, known as post-infectious/post-inflammatory IBS (PI-IBS). Although it is known that intestinal microbiota and host NOD-like receptor family pyrin domain containing 6 (NLRP6) inflammsome signaling are closely related to PI-IBS and moxibustion has a therapeutic effect on PI-IBS, whether moxibustion regulates the intestinal flora and host NLRP6 events in PI-IBS remains unclear.

AIM

To examine the regulatory effect of moxibustion on intestinal microbiota and host NLRP6 inflammatory signaling in PI-IBS.

METHODS

Sprague-Dawley rats were divided into a normal control group, a model control group, a mild moxibustion group, and a sham mild moxibustion group. PI-IBS rats in the mild moxibustion group were treated with moxibusiton at bilateral Tianshu (ST 25) and Zusanli (ST36) for 7 consecutive days for 10 min each time. The sham group rats were given the same treatment as the mild moxibustion group except the moxa stick was not ignited. Abdominal withdrawal reflex (AWR) score was measured to assess the visceral sensitivity, and colon histopathology and ultrastructure, colonic myeloperoxidase (MPO) activity, and serum C-reactive protein (CRP) level were measured to evaluate low-grade colonic inflammation in rats. The relative abundance of selected intestinal bacteria in rat feces was detected by 16S rDNA PCR and the NLRP6 inflammsome signaling in the colon was detected by immunofluorescence, qRT-PCR, and Western blot.

RESULTS

The AWR score was significantly decreased and the low-grade intestinal inflammation reflected by serum CRP and colonic MPO levels was inhibited in the mild moxibustion group compared with the sham group. Mild moxibustion remarkably increased the relative DNA abundances of Lactobacillus, Bifidobacterium, and Faecalibacterium prausnitzii but decreased that of Escherichia coli in the gut of PI-IBS rats. Additionally, mild moxibustion induced mRNA and protein expression of intestine lectin 1 but inhibited the expression of IL-1β, IL-18, and resistance-like molecule β by promoting the NLRP6 and reducing the mRNA and protein expression of apoptosis-associated speck-like protein containing CARD (ASC) and cysteinyl-aspartate-specific proteinase 1 (Caspase-1). The relative DNA abundances of Lactobacillus, Bifidobacteria, Faecalibacterium prausnitzii, and Escherichia coli in each group were correlated with the mRNA and protein expression of NLRP6, ASC, and Caspase-1 in the colon.

CONCLUSION

These findings indicated that mild moxibustion can relieve low-grade GI inflammation and alleviate visceral hypersensitivity in PI-IBS by regulating intestinal microbes and controlling NLRP6 inflammasome signaling.

Gastrointestinal motility and absorptive disorders in patients with inflammatory bowel diseases: Prevalence, diagnosis and treatment

Inflammatory bowel diseases (IBD), Crohn`s disease and ulcerative colitis, are chronic conditions associated with high morbidity and healthcare costs. The natural history of IBD is variable and marked by alternating periods of flare and remission. Even though the use of newer therapeutic targets has been associated with higher rates of mucosal healing, a great proportion of IBD patients remain symptomatic despite effective control of inflammation. These symptoms may include but not limited to abdominal pain, dyspepsia, diarrhea, urgency, fecal incontinence, constipation or bloating. In this setting, commonly there is an overlap with gastrointestinal (GI) motility and absorptive disorders. Early recognition of these conditions greatly improves patient care and may decrease the risk of mistreatment. Therefore, in this review we describe the prevalence, diagnosis and treatment of GI motility and absorptive disorders that commonly affect patients with IBD.

Radiographic dose-dependency study of loperamide effects on gastrointestinal motor function in the rat. Temporal relationship with nausea-like behavior

BACKGROUND

Loperamide is a potent mu opioid receptor agonist available over the counter to treat diarrhea. Although at therapeutic doses loperamide is devoid of central effects, it may exert them if used at high doses or combined with drugs that increase its systemic and/or central bioavailability. Recently, public health and scientific interest on loperamide has increased due to a growing trend of misuse and abuse, and consequent reports on its toxicity. Our aim was to evaluate in the rat the effects of increasing loperamide doses, with increasing likelihood to induce central effects, on gastrointestinal motor function (including gastric dysmotility and nausea-like behavior).

METHODS

Male Wistar rats received an intraperitoneal injection of vehicle or loperamide (0.1, 1, or 10 mg kg^-1 ). Three sets of experiments were performed to evaluate: (a) central effects (somatic nociceptive thresholds, immobility time, core temperature, spontaneous locomotor activity); (b) general gastrointestinal motility (serial X-rays were taken 0-8 hours after intragastric barium administration and analyzed semiquantitatively, morphometrically, and densitometrically); and (c) bedding intake (a rodent indirect marker of nausea). Animals from sets 1 and 3 were used to evaluate gastric dysmotility ex vivo at 2 and 4 hours after administration, respectively.

KEY RESULTS

Loperamide significantly induced antinociception, hypothermia, and hypolocomotion (but not catalepsy) at high doses and dose-dependently reduced gastrointestinal motor function, with the intestine exhibiting higher sensitivity than the stomach. Whereas bedding intake occurred early and transiently, gastric dysmotility was much more persistent.

CONCLUSIONS AND INFERENCES

Our results suggest that loperamide-induced nausea and gastric dysmotility might be temporally dissociated.

Current strategies toward safer mu opioid receptor drugs for pain management

INTRODUCTION

Pain relief remains a major public health challenge. The most efficient available painkillers are opioids targeting the mu opioid receptor (MOR). MORs are expressed in the areas of the brain [including pain and respiratory centers] that are important for processing reward and aversion. Thus, MOR activation efficiently alleviates severe pain, but the concomitant reward and respiratory depressant effects pose a threat; patients taking opioids potentially develop opioid addiction and high risk for overdose. Areas covered: Ongoing efforts to generate safer opioid analgesics are reviewed here. The design of biased compounds that trigger MOR induced G protein over β-arrestin signaling, peripheral opioids, drugs targeting MORs in heteromers and drugs enhancing endogenous opioid activity are discussed. Expert opinion: There is evidence that throttling MOR signaling may lead to an era of opioids that are truly efficient painkillers with lower side effects and risk of overdose. However, few of the drugs derived from the advanced approaches outlined here, are getting approval by regulatory committees for use in clinical settings. Thus, there is an urgent need to (i) better clarify mechanisms underlying the hazardous physiological effects of MOR activation, and (ii) fully validate the safety of these new MOR-based therapies.

Side effects associated with pharmacotherapy for pediatric irritable bowel syndrome and functional abdominal pain - not otherwise specified: a systematic review

INTRODUCTION

To systematically review the literature regarding the side effects of pharmacotherapy in children with irritable bowel syndrome (IBS) and functional abdominal pain - not otherwise specified (FAP-NOS). Areas covered: Cochrane Library, PubMed, and Embase databases were searched from inception to May 2018. The following inclusion criteria were applied: (1) randomized controlled trials (RCTs), cohort studies or case-control studies; (2) in children aged 4-18 years or adult studies if children are reported separately; (3) reporting a diagnosis of IBS or FAP-NOS as defined by the authors; and (4) reporting the occurrence of side effects of pharmacotherapy. Quality assessment of included studies was conducted. Expert opinion: A total of 4619 articles were identified; 17 were included. In 10/17 (59%) studies, side effects of pharmacotherapy (antispasmodics, antidepressants, antihistaminic agents, serotonergic agents and antibiotics) occurred. The majority of side effects were: (1) limited to the gastrointestinal tract and central nervous system and, 2) mild and transient. No serious adverse events were reported. This systematic review shows that data on safety in children with functional abdominal pain disorders are scarce, and highlights the lack of high-quality research for potential side effects of pediatric IBS and FAP-NOS. Further research by means of large well-designed-follow-up studies is necessary.