Update on Pharmacotherapy for Irritable Bowel Syndrome

Baizhu shaoyao decoction restores the intestinal barrier and brain-gut axis balance to alleviate diarrhea-predominant irritable bowel syndrome via FoxO1/FoxO3a

BACKGROUND

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common functional gastrointestinal disease. Besides, baizhu shaoyao decoction (BSD) is an effective treatment for IBS-D; however, its mechanism of action remains unclear.

PURPOSE

This study aims to assess the ability of BSD to therapy IBS-D and to elucidate the underlying mechanism.

METHODS

First, comprehensive analyses, including ADME (absorption, distribution, metabolism, excretion) screening, Venn analysis, Gene Ontology (GO) analysis, and network construction, were performed to characterize IBS-D-related pathways and explore the synergistic effects of BSD active compounds. Next, an IBS-D model was constructed using a three-factor superposition method of neonatal maternal separation, chronic immobilization stress stimulation, and Sennae folium aqueous extract lavage. Moreover, the impact of BSD was assessed based on the body weight, fecal water content, and abdominal withdrawal reflex (AWR), and the results of the open field test, sucrose preference test, intestinal permeability assessment, transmission electron microscopy, and TdT-mediated dUTP nick-end labeling (TUNEL) analysis. The factors that regulate the BSD effects on IBS-D were estimated using immunoblotting, quantitative reverse transcription polymerase chain reaction (q-RTPCR), immunohistochemistry, and transcriptome sequencing analyses.

RESULTS

We found that BSD improved depressive behavior, brain-gut peptide levels, and intestinal permeability induced by IBS-D by increasing the abundance of intestinal tight junctions. In addition, BSD reduced secretory immunoglobulin A levels and the number of intestinal mast cells in IBS-D rats. Network pharmacology and transcriptome sequencing analysis further revealed that the forkhead box O (FoxO) signaling pathway contributed to the BSD-induced alleviation of IBS-D, as BSD regulated the protein and mRNA levels of FoxO1, glycogen synthase kinase 3β, and FoxO3a. Importantly, a FoxO1 inhibitor effectively alleviated IBS-D symptoms in rats, whereas a FoxO3a agonist had the opposite effects.

CONCLUSION

These results demonstrate that BSD alleviates depression and intestinal symptoms by regulating brain-gut peptide expression and restoring the intestinal barrier function via the FoxO signaling pathway. Furthermore, our study uses serum pharmacochemistry technology to analyze the in vivo components of TCM formula under effective condition, solving the problem of the discovery of the effective components of TCM to some extent.

Deciphering chemical and metabolite profiling of Chang-Kang-Fang by UPLC-Q-TOF-MS/MS and its potential active components identification

Chang-Kang-Fang (CKF) formula, a Traditional Chinese Medicine (TCM) prescription, has been widely used for the treatment of irritable bowel syndrome (IBS). However, its potential material basis and underlying mechanism remain elusive. Therefore, this study employed an integrated approach that combined ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) with network pharmacology to systematically characterize the phytochemical components and metabolites of CKF, as well as elucidating its underlying mechanism. Through this comprehensive analysis, a total of 150 components were identified or tentatively characterized within the CKF formula. Notably, six N-acetyldopamine oligomers from CicadaePeriostracum and eight resin glycosides from Cuscutae Semen were characterized in this formula for the first time. Meanwhile, 149 xenobiotics (58 prototypes and 91 metabolites) were detected in plasma, urine, feces, brain, and intestinal contents, and the in vivo metabolic pathways of resin glycosides were elaborated for the first time. Furthermore, network pharmacology and molecular docking analyses revealed that alkaloids, flavonoids, chromones, monoterpenes, N-acetyldopamine dimers, p-hydroxycinnamic acid, and Cus-3/isomer might be responsible for the beneficial effects of CKF in treating IBS, and CASP8, MARK14, PIK3C, PIK3R1, TLR4, and TNF may be its potential targets. These discoveries offer a comprehensive understanding of the potential material basis and clarify the underlying mechanism of the CKF formula in treating IBS, facilitating the broader application of CKF in the field of medicine.

Discovery of Tenapanor: A First-in-Class Minimally Systemic Inhibitor of Intestinal Na+/H+ Exchanger Isoform 3

We present herein the design, synthesis, and optimization of gut-restricted inhibitors of Na⁺/H⁺ exchanger isoform 3 (NHE3). NHE3 is predominantly expressed in the kidney and gastrointestinal tract where it acts as the major absorptive sodium transporter. We desired minimally systemic agents that would block sodium absorption in the gastrointestinal tract but avoid exposure in the kidney. Starting with a relatively low-potency highly bioavailable hit compound (1), potent and minimally absorbed NHE3 inhibitors were designed, culminating with the discovery of tenapanor (28). Tenapanor has been approved by the U.S. Food and Drug Administration (FDA) for the treatment of irritable bowel syndrome with constipation in adults.

Clinical evaluation of the effect of Zataria multiflora Boiss and Trachyspermum copticum (L.) on the patients with irritable bowel syndrome

BACKGROUND AND AIM

Irritable Bowel Syndrome (IBS) is the most common gastrointestinal dysfunction characterized by abdominal pain or discomfort, as well as changes in bowel movements and stool shape. Given the global trend towards the increased use of complementary and alternative medicine (CAM), the high prevalence of IBS, the lack of a standard treatment for all IBS subtypes, and patients' willingness to use CAM treatments, investigations into CAM treatments are needed. Accordingly, the present study aimed to investigate the effect of a mix of two herbal medicines (Zataria-Trachyspermum, ZT) on the clinical symptoms of patients with IBS.

EXPERIMENTAL PROCEDURE

The present study was performed on 3 groups including the positive control, experimental, and placebo groups. The sample size was calculated as 150 participants. Fifty patients were assigned to one of three parallel groups (ZT capsule, placebo, and mebeverine capsule) by block randomization. All three groups were treated for 4 weeks. The patients were monitored in the follow-up stage for 2 additional weeks.

RESULTS

After the fourth week of intervention, symptoms of pain, bloating, and reflux showed a significant decrease in the ZT group compared to the placebo and mebeverine groups (P <0.05). Moreover, the participants in the ZT group reported a significant decrease in fatigue compared to the other two groups (P <0.05).

CONCLUSION

This study confirmed the positive effect of ZT on IBS symptoms, especially pain, bloating, constipation, and bowel movements.

Irritable Bowel Syndrome in Pregnancy

Irritable bowel syndrome (IBS) affects a significant percentage of the general population and is more common in women. A large proportion of women affected with IBS are of childbearing age; however, there is a paucity of studies and guidelines to specifically address the epidemiology, course, maternal/fetal prognosis, or management of IBS in pregnancy. This scarcity of literature on IBS and pregnancy poses significant challenges to healthcare providers in counseling and managing patients. In this comprehensive review, we summarize the current literature and knowledge gaps regarding the effects of pregnancy on IBS and vice versa, along with the efficacy and safety profiles of commonly used IBS diets and medications in pregnancy. The management of pregnant women with IBS should be multidisciplinary, with emphasis on education and judicious use of dietary modifications and pharmacologic options that are deemed relatively safe during pregnancy.

Efficacy of opioid receptor modulators in patients with irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

While irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal diseases in clinical practice, it has diverse pathogenesis. Because of its sudden and lingering intractable symptoms, it seriously affects patients work and life. Opioid receptors are G protein-coupled receptors distributed across the brain, spinal cord, skin, and gastrointestinal tract, and each of the subtypes has a unique role and specific distribution. They play a role in regulating gastrointestinal motility, secretion, and visceral sensations in the gastrointestinal tract. Therefore, this meta-analysis aims to evaluate the effects of opioid receptor modulators on improving the symptoms of IBS.

METHODS

Searching the key words (Irritable Bowel Syndromes or Syndrome, Irritable Bowel OR Syndromes, Irritable Bowel OR Colon, Irritable OR Irritable Colon OR Colitis, Mucous OR Colitides, Mucous OR Mucous Colitides OR Mucous Colitis) AND (opioid receptor modulators OR eluxadoline OR Viberzi OR asimadoline OR loperamide), a preliminary search on PubMed (English), EMBASE (English), Cochrane Library (English), China National Knowledge Infrastructure Database (CNKI, Chinese), WanFang (Chinese), VIP citation databases (Chinese) and SinoMed (Chinese) databases yielded 1023 papers published in English and Chinese from inception to July 1, 2019. Nine studies were included in the final meta-analysis. Because this is a systematic review and meta-analysis, ethical approval is not necessary.

RESULTS

The random-effects meta-analysis based on these 9 studies and their 4156 patients found that opioid receptor modulators have a statistically significant beneficial effect on IBS global symptoms (RR = 0.85, 95%CI = 0.79-0.92, P < .01) and bowel movement frequency (SMD = -1.26, 95%CI = -2.49--0.04, P < .05), and while there was an improvement trend in stool consistency and quality of life, these findings were not statistically significant.

CONCLUSIONS

This is the first meta-analysis to examine the use of opioid receptor modulators in IBS, and few adverse events were reported in the available trials. Compared with the control group, eluxadolin has a better effect in improving IBS global symptoms and abdominal pain and has statistical significance and showed a low rate of constipation development in IBS patients in comparison with known effects of other opioid receptor modulators. However, current findings are based on a considerably limited evidence base with marked heterogeneity. Future studies should aim to identify subpopulations of patients with IBS and need to evaluate the long-term safety of these therapies.PROSPERO registration number: CRD42020141597.

Shortcomings of Trials Assessing Antidepressants in the Management of Irritable Bowel Syndrome: A Critical Review

Irritable bowel syndrome (IBS) is a common disorder requiring complex, multidisciplinary management. Antidepressants are commonly used and recommended in guidelines for the treatment of patients with IBS. We assessed randomized controlled trials (RCTs) on antidepressants in patients with IBS, with specific attention to study design and data quality/reporting characteristics. Following a comprehensive search, data and RCT characteristics were systematically summarized. Fragility index, representing the number of positive “events” that the study relies on for its significance, was calculated. Eighteen RCTs were included. Overall, tricyclic antidepressants (TCAs), but not selective serotonin reuptake inhibitors (SSRIs), appeared to be efficacious in IBS. Eight studies reported on adverse events (AEs), which were significantly greater in patients receiving antidepressants versus placebo. The median (mean) fragility index of TCA trials was 0 (1.5). RCTs with positive results had significantly lower placebo rates (20.8%) versus negative studies (45.7%; p < 0.0001). RCTs exhibited limitations related to study design (sample size and blinding), data analysis (outcomes and placebo response), and data reporting (selective reporting of AEs and publication bias). Careful consideration of limitations of RCTs on antidepressants in IBS is warranted to formulate a safe and beneficial treatment regimen for patients with IBS.

Efficacy of Lactobacillus paracasei HA-196 and Bifidobacterium longum R0175 in Alleviating Symptoms of Irritable Bowel Syndrome (IBS): A Randomized, Placebo-Controlled Study

Specific probiotic strains can alleviate the gastrointestinal (GI) symptoms and psychiatric comorbidities of irritable bowel syndrome (IBS). In this randomized, double-blind, placebo-controlled study, the efficacy of Lactobacillus paracasei HA-196 (L. paracasei) and Bifidobacterium longum R0175 (B. longum) in reducing the GI and psychological symptoms of IBS was evaluated in 251 adults with either constipation (IBS-C), diarrhea (IBS-D), or mixed-pattern (IBS-M). Following a 2-week run-in period, participants were randomized to one of three interventions: L. paracasei (n = 84), B. longum (n = 83) or placebo (n = 81). IBS symptoms, stool frequency and consistency and quality of life were assessed by questionnaires. The differences from baseline in the severity of IBS symptoms at 4 and 8 weeks were similar between groups. Participants in this study were classified, after randomization, into subtypes according to Rome III. Within the L. paracasei group, complete spontaneous and spontaneous bowel movement frequency increased in participants with IBS-C (n = 10) after 8 weeks of supplementation (both p < 0.05) and decreased in participants with IBS-D (n = 10, p = 0.013). Both L. paracasei and B. longum supplementation improved the quality of life in emotional well-being and social functioning compared with baseline (all p < 0.05). In conclusion, L. paracasei and B. longum may reduce GI symptom severity and improve the psychological well-being of individuals with certain IBS subtypes.

Efficacy and Safety of Probiotics, Prebiotics and Synbiotics in the Treatment of Irritable Bowel Syndrome: A systematic review and meta-analysis

Treatments that target alterations in gut microbiota may be beneficial for patients with irritable bowel syndrome (IBS). A systematic review and meta-analysis was conducted of randomised clinical trials (RCTs) evaluating the efficacy and safety of probiotics, prebiotics and synbiotics. Factors considered in the analysis included global IBS symptoms and/or abdominal pain, secondary symptoms and the frequency of adverse events. A total of 33 RCTs involving 4,321 patients were identified. Overall, probiotics significantly improved global IBS symptoms compared to placebos (standardised mean difference = −0.32, 95% confidence interval: −0.48 to −0.15; P <0.001), with significant heterogeneity between studies (I² = 72%; P <0.001). This remained apparent in both single- and multi-strain probiotic interventions as well as synbiotic formulations. However, evidence regarding prebiotics was scarce. There were no significant inter-group differences in terms of the frequency of adverse events. Future RCTs should address methodological limitations, including short follow-up periods and patient adherence.

Randomized Clinical Trial: Crofelemer Treatment in Women With Diarrhea-Predominant Irritable Bowel Syndrome

INTRODUCTION

Crofelemer, the active compound purified from latex of Croton lechleri, has been shown to improve HIV and traveler's diarrhea and improve pain in women with irritable bowel syndrome-diarrhea (IBS-D). This trial evaluated the effect of crofelemer on abdominal pain in women with IBS-D.

METHODS

Women with IBS-D were randomized to crofelemer (125 mg) or placebo twice daily for 12 weeks. The primary efficacy endpoint was overall change in percentage of abdominal pain/discomfort-free days. Post hoc analysis for Food and Drug Administration (FDA) monthly responders was performed for stool consistency, abdominal pain, and combined stool consistency and abdominal pain.

RESULTS

A total of 240 women were enrolled. There was no significant difference in overall percentage of pain/discomfort-free day between the groups. In post hoc analysis, FDA abdominal pain monthly responders were significantly more likely during months 1 through 2 (58.3% vs 45.0%, P = 0.030) as well as during the entire 3 months (54.2% vs 42.5%, P = 0.037) in the crofelemer group when compared with placebo. However, there was no significant difference in the percentage of FDA stool consistency monthly responders or combined stool consistency and pain monthly responders between the groups. Crofelemer had a safety profile similar to placebo.

DISCUSSION

Crofelemer did not significantly improve abdominal pain over placebo by the primary endpoint. However, it did based on the FDA abdominal pain monthly responder endpoint. This suggests that crofelemer may have a role in the treatment of abdominal pain associated with IBS-D. Further studies are warranted to evaluate the potential of crofelemer as a visceral analgesic.

Current and emerging pharmacological approaches for treating diarrhea-predominant irritable bowel syndrome

Introduction: Irritable bowel syndrome with diarrhea (IBS-D) is among the most common functional gastrointestinal (GI) disorders and is associated with impaired quality of life, increased health-care utilization, and significant costs to patients and society. The treatment of IBS is typically hierarchal with initial therapies consisting of dietary and lifestyle modifications. Pharmacotherapy with over-the-counter and prescription medications is also commonly used for symptomatic control in the course of therapy.Areas covered: Three medications are approved by the United States Food and Drug Administration (FDA) for IBS-D, with all of them demonstrating efficacy in randomized, placebo-controlled trials. In this review, the authors discuss the clinical trial data applicable to the current FDA approved IBS-D therapies as well as review data related to new and emerging therapies for this condition.Expert opinion: Clinicians should be familiar with emerging therapies for IBS-D as they may provide benefit to some IBS-D patients. The exact mechanisms of action of many of the emerging agents for IBS-D remain unknown. Despite substantial differences and limitations in the design and quality of supporting studies, there is an increasing body of evidence suggesting that emerging agents may promote meaningful symptom improvement in patients with IBS-D.