Effect of a calcium channel blocker and antispasmodic in diarrhoea-predominant irritable bowel syndrome

The role of the gut microbiome in disorders of gut-brain interaction

Disorders of Gut-Brain Interaction (DGBI) are widely prevalent and commonly encountered in gastroenterology practice. While several peripheral and central mechanisms have been implicated in the pathogenesis of DGBI, a recent body of work suggests an important role for the gut microbiome. In this review, we highlight how gut microbiota and their metabolites affect physiologic changes underlying symptoms in DGBI, with a particular focus on their mechanistic influence on GI transit, visceral sensitivity, intestinal barrier function and secretion, and CNS processing. This review emphasizes the complexity of local and distant effects of microbial metabolites on physiological function, influenced by factors such as metabolite concentration, duration of metabolite exposure, receptor location, host genetics, and underlying disease state. Large-scale in vitro work has elucidated interactions between host receptors and the microbial metabolome but there is a need for future research to integrate such preclinical findings with clinical studies. The development of novel, targeted therapeutic strategies for DGBI hinges on a deeper understanding of these metabolite-host interactions, offering exciting possibilities for the future of treatment of DGBI.

The Role of Ion Channels in Functional Gastrointestinal Disorders (FGID): Evidence of Channelopathies and Potential Avenues for Future Research and Therapeutic Targets

Several gastrointestinal (GI) tract abnormalities, including visceral hypersensitivity, motility, and intestinal permeability alterations, have been implicated in functional GI disorders (FGIDs). Ion channels play a crucial role in all the functions mentioned above. Hormones and natural molecules modulate these channels and represent targets of drugs and bacterial toxins. Mutations and abnormal functional expression of ion channel subunits can lead to diseases called channelopathies. These channelopathies in gastroenterology are gaining a strong interest, and the evidence of co-relationships is increasing. In this review, we describe the correlation status between channelopathies and FGIDs. Different findings are available. Among others, mutations in the ABCC7/CFTR gene have been described as a cause of constipation and diarrhea. Mutations of the SCN5A gene are instead associated with irritable bowel syndrome. In contrast, mutations of the TRPV1 and TRPA genes of the transient receptor potential (TRP) superfamily manifest hypersensitivity and visceral pain in sensory nerves. Recently, mice and humans affected by Cantu syndrome (CS), which is associated with the mutations of the KCNJ8 and ABCC9 genes encoding for the Kir6.1 and SUR2 subunits, showed dysfunction of contractility throughout the intestine and death in the mice after the weaning on solid food. The discovery of a correlation between channelopathies and FIGD opens new avenues for discovering new direct drug targets for specific channelopathies, leading to significant implications for diagnosing and treating functional GI diseases.

Indian consensus statements on irritable bowel syndrome in adults: A guideline by the Indian Neurogastroenterology and Motility Association and jointly supported by the Indian Society of Gastroenterology

The Indian Neurogastroenterology and Motility Association (INMA), earlier named the Indian Motility and Functional Diseases Association developed this evidence-based practice guidelines for the management of irritable bowel syndrome (IBS). A modified Delphi process was used to develop this consensus containing 28 statements, which were concerning diagnostic criteria, epidemiology, etiopathogenesis and comorbidities, investigations, lifestyle modifications and treatments. Owing to the Coronavirus disease-19 (COVID-19) pandemic, lockdowns and mobility restrictions, web-based meetings and electronic voting were the major tools used to develop this consensus. A statement was regarded as accepted when the sum of "completely accepted" and "accepted with minor reservation" voted responses were 80% or higher. Finally, the consensus was achieved on all 28 statements. The consensus team members are of the view that this work may find use in teaching, patient care, and research on IBS in India and other nations.

The effects of Saccharomyces boulardii on rat colonic hypermotility induced by repeated water avoidance stress and the potential mechanism

Background

Saccharomyces boulardii (Sb) has been reported to have the potential to regulate gut motility. The aim of this experiment was to explore the possible function of Sb in gut hypermotility elicited by repeated water avoidance stress (WAS).

Methods

Adult male Wistar rats (N = 24) were divided into one of the following three groups: control (C), NS (normal saline) + WAS group (N), and Sb + WAS group (S). A diarrhea-predominant irritable bowel syndrome (IBS-D) model in rats was induced using the WAS method. Gut motility was evaluated by stool pellet expulsion per hour. The contractile activity of the colonic muscle strips was measured using an RM6240 multichannel physiological signal instrument. qRT-PCR and immunohistochemistry were used to assess Toll-like receptor 4 (TLR4) expression in colon tissue. ELISA was used to measure the level of cytokines in the serum and colonic tissue. Also, the microbiota composition was determined using high-throughput 16S rRNA sequencing.

Result

The results showed that oral Sb decreased the WAS-induced increased defecation and colonic hypermotility in vivo. Furthermore, Sb also decreased the contractile amplitude of colonic circular muscle (CM) and longitudinal muscle (LM) strips in a dose-dependent manner in vitro. Repeated WAS increased TLR4 expression, but Sb reversed it. Sb also reduced interleukin-6 (IL-6), IL-1β, and interferon-γ (IFN-γ) levels in serum and colonic tissue, while increasing IL-10 levels in colonic tissue. Meanwhile, the rats from the NS + WAS group had decreased microbiota diversity and had lower relative abundances of Patescibacteria, Epsilonbacteraeota, Cyanobacteria, and Turicibacter compared with controls. The rats in the Sb + WAS group showed a tendency to increase the relative abundance of Blautia when compared to control rats and had lower relative abundances of Acidobacteria and Anaerostipes compared with the NS + WAS group.

Conclusion

Our findings demonstrated that Sb improved colonic hypermotility in rats, reversed the high-expression of TLR4 in the colon caused by repeated WAS, modulated cytokines in the colon and serum, and altered the gut microbiota, indicating that Sb may be useful for IBS-D.

The Efficacy of Mebeverine in the Treatment of Irritable Bowel Syndrome-A Systematic Review

BACKGROUND

Irritable bowel syndrome (IBS) is a common gastrointestinal tract disorder, affecting 10-20% of adults worldwide. Mebeverine is an antispasmodic agent indicated for the symptomatic treatment of abdominal pain caused by intestinal smooth muscle spasms and intestinal functional disorders in the course of IBS. The aim of this article was to perform a systematic literature review and update previous overviews of the efficacy and safety of mebeverine treatment in IBS.

METHODS

Major electronic medical databases, PubMed, EMBASE and Cochrane, were systematically searched from January 1965 to January 2021.

RESULTS

Twenty-two studies met our inclusion criteria, including 19 randomised trials, two observational retrospective studies, and one non-randomised, single-blinded study. Six studies reported a significant decrease in abdominal pain after mebeverine treatment (p-values ranging from <0.05 to <0.001). Only three studies showed no improvement after mebeverine treatment in terms of the severity of abdominal pain or discomfort. Some of the included studies also showed significant improvements in abnormal bowel habits, abdominal distension, as well as stool frequency and consistency. Adverse events were rare and associated mainly with IBS symptoms.

CONCLUSIONS

Mebeverine is an effective treatment option in IBS, with a good safety profile and low frequency of adverse effects.

Efficacy of pinaverium bromide in the treatment of irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

Spasmolytic agents are an attractive first line treatment option for irritable bowel syndrome (IBS). Pinaverium bromide (pinaverium) has antispasmodic effects on gastrointestinal smooth muscle and can relieve major IBS symptoms, but an up-to-date meta-analysis comparing the efficacy of pinaverium with placebo is lacking. The aim is to perform a systematic review and meta-analysis to assess the efficacy of pinaverium compared with placebo for IBS treatment.

METHODS

All placebo-controlled trials evaluating pinaverium for IBS treatment were included, up to October 2019. Treatment efficacy was evaluated by overall patient IBS symptoms. Individual symptoms were also evaluated. The effect of pinaverium versus placebo was expressed as standardized mean difference (SMD) and risk ratio (RR). Odds ratio (OR) and number needed to treat (NNT) were also calculated.

RESULTS

Eight studies were included for analysis. Pinaverium treatment had a beneficial effect on overall IBS symptom relief with a positive SMD of 0.64 [95% confidence interval (CI) 0.45-0.82, p < 0.0001] and a positive RR of 1.75 (1.26-2.43, p < 0.0008). No significant difference was found by publication year, gender, age, methodological quality score (MQS), or sample size. No publication bias was detected. OR was 3.43 (2.00-5.88, p < 0.0001), and NNT was 4. Pinaverium also demonstrated a beneficial treatment effect for abdominal pain, stool change, and bloating improvement or resolution.

CONCLUSION

Pinaverium is superior to placebo for the treatment of IBS symptoms, irrespective of patient age or gender, study publication year, sample size, or MQS. The NNT in this meta-analysis is amongst the lowest for studies and meta-analyses of antispasmodics versus placebo in IBS.

Synthesis of N-Methylmorpholinium Derivatives Possessing a 1,3,4-Oxadiazole Core as Feasible Antibacterial Agents against Plant Bacterial Diseases

To develop a kind of quaternary ammonium compounds that can safely apply in agriculture for managing the plant bacterial diseases, herein, a series of N-methylmorpholinium derivatives possessing a classical 1,3,4-oxadiazole core were prepared and the antibacterial activities both in vitro and in vivo were screened. Bioassay results revealed that compounds 3l and 3i showed the strongest antibacterial activity toward pathogens Xanthomonas oryzae pv. oryzae and X. axonopodis pv. citri with the lowest EC50 values of 1.40 and 0.90 μg/mL, respectively. Phytotoxicity test trials indicated that target compounds bearing a bulky N-methylmorpholinium pendant are safe for plants. The following in vivo bioassays showed that compound 3l could control the rice bacterial blight disease, thereby affording good control efficiencies of 55.95% (curative activity) and 53.09% (protective activity) at the dose of 200 μg/mL. Preliminary antibacterial mechanism studies suggested that target compounds had strong interactions with the cell membrane of bacteria via scanning electron microscopy imaging. Additionally, this kind of framework also displayed certain antifungal activity toward Fusarium oxysporum and Phytophthora cinnamomi. Given the above privileged characteristics, this kind of 1,3,4-oxadiazole-tailored N-methylmorpholinium derivatives could stimulate the design of safe quaternary ammonium bactericides for controlling plant bacterial diseases.

Characteristics of Contents of Lower intestine in the 65-74 Years of Age Range Could Impact the Performance of Safe and Efficacious Modified Release Products

We characterized the contents of distal ileum and proximal colon of older people from a pharmaceutical product performance perspective, under two extreme situations, i.e. 5 h after a glass of water to fasted volunteers (fasted state) and 5 h after a high-calorie, high-fat meal to fasted volunteers (fed state). Five males and three females (65-70 y) participated in a two-phase crossover study. Contents were collected via colonoscopy. In distal ileum, luminal pH was lower and buffer capacity was higher than in young adults; differences reached significance for pH in the fed state. In proximal colon, differences reached significance for pH/fasted state and for buffer capacity/both fasted and fed states. Aqueous fraction of contents contained more short chain fatty acids than previously observed in young adults. In distal ileum, osmolality was significantly higher than in young adults. In proximal colon, aqueous fraction in the fasted state was significantly lower and long chain fatty acids 5 h after meal was significantly higher than in young adults. Characteristics of contents of lower intestine that are relevant to the performance of certain modified release products differ between individuals 65-74 years old and young adults, the typical age group employed in safety and efficacy studies of oral drug products.

Irritable Bowel Syndrome: News from an Old Disorder

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder, which can affect all members of a society, regardless of age, sex, race or socioeconomic status. Because of its high prevalence and chronic nature, it represents a significant economic burden. In fact, these patients have a relevant impairment of their quality of life, which limits their work productivity and daily social activities, especially when it is associated with other disorders, such as anxiety and depression. The diagnosis of IBS relies on symptom-based diagnostic criteria with normal results on a limited number of complementary tests that rule out other possible diagnoses. The aetiology of this condition is incompletely established. However, evidence suggests that it is a multifactorial disorder with several different mechanisms that have been implicated as responsible for the symptoms. Since the treatment strategy is usually based on predominant symptoms and their severity, it is important to recognise the underlying mechanisms in order to successfully relief the visceral pain and altered bowel habits. The aim of this non-systematic review of the literature was to explore the pathophysiology and treatment options of IBS, highlighting the most recent evidence, from the new Rome IV criteria to the new drug armamentarium.

Will controlled release mebeverine be able to surpass placebo in treatment of diarrhoea predominant irritable bowel syndrome?

BACKGROUND AND AIMS

Irritable bowel syndrome (IBS) is a chronic relapsing disorder characterized by abdominal pain-discomfort and altered bowel habits. The IBS-diarrhoea predominant subtype (IBS-D) is defined as >25% of bowel movements representing type 6 or 7 of the Bristol Stool Form Scale. Management of IBS-D is mainly symptomatic, including lifestyle modification. Due to absence of standard treatment, multiple drugs are used. A controlled release (CR) form of mebeverine, recommended for spasmodic gastrointestinal disorders (including IBS) has recently been introduced in Indian market. We have conducted a placebo-controlled double blind randomized controlled trial [CTRI/2018/03/012897] to evaluate the effectiveness and safety of this product.

METHODS

40 patients of IBS-D were recruited from medicine out-patient department (OPD) of a tertiary care hospital and randomized to two parallel groups. One received mebeverine 200 mg CR tablets twice daily for 8 weeks, while other received matching placebo. Outcome parameters were number of bowel movements per day over past 7 days (NoBM7d), severity of abdominal cramps and IBS quality of life (IBSQoL) score. Medication adherence record and treatment emergent adverse events were captured.

RESULTS

Mebeverine group showed modest but statistically significant improvement in NoBM7d, cramps and IBSQoL from baseline to 4 and 8 weeks. The changes within the placebo group were not statistically significant. Also, the intergroup differences at both 4 and 8 weeks were not statistically significant. Adherence was better in mebeverine group and both interventions were well tolerated.

CONCLUSIONS

Mebeverine 200 mg CR twice daily has modest effect in IBS-D and therefore will not be a good choice for patients with severe symptoms.

Second Asian Consensus on Irritable Bowel Syndrome

BACKGROUND/AIMS

There has been major progress in our understanding of the irritable bowel syndrome (IBS), and novel treatment classes have emerged. The Rome IV guidelines were published in 2016 and together with the growing body of Asian data on IBS, we felt it is timely to update the Asian IBS Consensus.

METHODS

Key opinion leaders from Asian countries were organized into 4 teams to review 4 themes: symptoms and epidemiology, pathophysiology, diagnosis and investigations, and lifestyle modifications and treatments. The consensus development process was carried out by using a modified Delphi method.

RESULTS

Thirty-seven statements were developed. Asian data substantiate the current global viewpoint that IBS is a disorder of gut-brain interaction. Socio-cultural and environmental factors in Asia appear to influence the greater overlap between IBS and upper gastrointestinal symptoms. New classes of treatments comprising low fermentable oligo-, di-, monosacharides, and polyols diet, probiotics, non-absorbable antibiotics, and secretagogues have good evidence base for their efficacy.

CONCLUSIONS

Our consensus is that all patients with functional gastrointestinal disorders should be evaluated comprehensively with a view to holistic management. Physicians should be encouraged to take a positive attitude to the treatment outcomes for IBS patients.

Pharmacologic Agents for Chronic Diarrhea

Chronic diarrhea is usually associated with a number of non-infectious causes. When definitive treatment is unavailable, symptomatic drug therapy is indicated. Pharmacologic agents for chronic diarrhea include loperamide, 5-hydroxytryptamine type 3 (5-HT3) receptor antagonists, diosmectite, cholestyramine, probiotics, antispasmodics, rifaximin, and anti-inflammatory agents. Loperamide, a synthetic opiate agonist, decreases peristaltic activity and inhibits secretion, resulting in the reduction of fluid and electrolyte loss and an increase in stool consistency. Cholestyramine is a bile acid sequestrant that is generally considered as the first-line treatment for bile acid diarrhea. 5-HT3 receptor antagonists have significant benefits in patients with irritable bowel syndrome (IBS) with diarrhea. Ramosetron improves stool consistency as well as global IBS symptoms. Probiotics may have a role in the prevention of antibiotic-associated diarrhea. However, data on the role of probiotics in the treatment of chronic diarrhea are lacking. Diosmectite, an absorbent, can be used for the treatment of chronic functional diarrhea, radiation-induced diarrhea, and chemotherapy-induced diarrhea. Antispasmodics including alverine citrate, mebeverine, otilonium bromide, and pinaverium bromide are used for relieving diarrheal symptoms and abdominal pain. Rifaximin can be effective for chronic diarrhea associated with IBS and small intestinal bacterial overgrowth. Budesonide is effective in both lymphocytic colitis and collagenous colitis. The efficacy of mesalazine in microscopic colitis is weak or remains uncertain. Considering their mechanisms of action, these agents should be prescribed properly.

Irritable bowel syndrome: The evolution of multi-dimensional looking and multidisciplinary treatments

Irritable bowel syndrome (IBS) is common in the society. Among the putative pathogeneses, gut dysmotility results in pain and disturbed defecation. The latter is probably caused by the effect of abnormal gut water secretion. The interaction between abnormal gas accumulation, abdominal pain and bloating remains controversial. Visceral hypersensitivity and its modification along with the central transmission are the characteristics of IBS patients. The identification of biologic markers based on genetic polymorphisms is undetermined. Imbalanced gut microbiota may alter epithelial permeability to activate nociceptive sensory pathways which in turn lead to IBS. Certain food constituents may exacerbate bowel symptoms. The impact of adult and childhood abuses on IBS is underestimated. Using the concept of biopsychosocial dysfunction can integrate multidimensional pathogeneses. Antispasmodics plus stool consistency modifiers to treat the major symptoms and defecation are the first-line drug treatment. New drugs targeting receptors governing bowel motility, sensation and secretion can be considered, but clinicians must be aware of their potential serious side effects. Psychiatric drugs and modalities may be the final options for treating intractable subjects. Probiotics of multi-species preparations are safe and worth to be considered for the treatment. Antibiotics are promising but their long-term safety and effectiveness are unknown. Diet therapy including exclusion of certain food constituents is an economic measure. Using relatively safe complementary and alternative medicines (CAMs) may be optional to those patients who failed classical treatment. In conclusion, IBS is a heterogeneous disorder with multidimensional pathogeneses. Personalized medicines with multidisciplinary approaches using different classes of drugs, psychiatric measures, probiotics and antibiotics, dietary therapy, and finally CAMs, can be considered.

Magnolol inhibits colonic motility through down-regulation of voltage-sensitive L-type Ca2+ channels of colonic smooth muscle cells in rats

This study aimed to investigate the effect of magnolol (5,5'-diallyl-2,2'-biphenyldiol) on contraction in distal colonic segments of rats and the underlying mechanisms. Colonic segments were mounted in organ baths for isometric force measurement. Whole-cell voltage-sensitive L-type Ca(2+) currents were recorded on isolated single colonic smooth muscle cells using patch-clamp technique. The spontaneous contractions and acetylcholine (ACh)- and Bay K 8644-induced contractions were inhibited by magnolol (3-100 μM). In the presence of Bay K8644 (100 nM), magnolol (10-100 μM) inhibited the contraction induced by 10 μM ACh. By contrast, tetrodotoxin (100 nM) and Nώ-nitro-L-arginine methyl ester (L-NAME 100 μM) did not change the inhibitory effect of magnolol (10 μM). In addition, magnolol (3-100 μM) inhibited the L-type Ca(2+) currents. The present results suggest that magnolol inhibits colonic smooth muscle contraction through downregulating L-type Ca(2+) channel activity.

HEF-19-induced relaxation of colonic smooth muscles and the underlying mechanisms

AIM: To investigate the relaxant effect of chromane HEF-19 on colonic smooth muscles isolated from rabbits, and the underlying mechanisms.

METHODS: The relaxant effect and action mechanisms of HEF-19 were investigated using descending colon smooth muscle of the rabbits. Preparations 1 cm long were mounted in 15-mL tissue baths containing Tyrode’s solution, maintained at 37 ± 0.5 °C and aerated with a mixture of 5% CO₂ in oxygen (Carbogen). The tension and amplitude of the smooth muscle strips were recorded after adding HEF-19 (10^-6, 10^-5 and 10^-4 mol/L). After cumulative administration of four antispasmodic agents, including acetylcholine chloride (Ach) (10^-4 mol/L), histamine (10^-4 mol/L), high-K⁺ (60 mmol/L) and BaCl₂ (8.2 mmol/L), HEF-19 (3 × 10^-7-3 × 10^-4 mol/L) was added to investigate the relaxant effect of HEF-19. CaCl₂ (10^-4-2.5 × 10^-3 mol/L) was added cumulatively to the smooth muscle preparations pretreated with and without HEF-19 (1 × 10^-6 or 3 × 10^-6 mol/L) and verapamil (1 × 10^-7 mol/L) to study the mechanisms involved. Finally, phasic contraction was induced with ACh (15 × 10^-6 mol/L), and CaCl₂ (4 × 10^-3 mol/L) was added to the smooth muscle preparations pretreated with and without HEF-19 (3 × 10^-6 mol/L or 1 × 10^-5 mol/L) and verapamil (1 × 10^-7 mol/L) in calcium-free medium to further study the underlying mechanisms.

RESULTS: HEF-19 (1 × 10^-6, 1 × 10^-5 and 1 × 10^-4 mol/L) suppressed spontaneous contraction of rabbit colonic smooth muscles. HEF-19 (3 × 10^-7-3 × 10^-4 mol/L) relaxed in a concentration-dependent manner colonic smooth muscle preparations pre-contracted with BaCl₂, high-K⁺ solution, Ach or histamine with respective EC₅₀ values of 5.15 ± 0.05, 5.12 ± 0.08, 5.58 ± 0.16 and 5.25 ± 0.24, thus showing a spasmolytic activity. HEF-19 (1 × 10^-6 mol/L and 3 × 10^-6 mol/L) shifted the concentration-response curves of CaCl₂ to the right and depressed the maximum response to CaCl_2. The two components contracted by Ach were attenuated with HEF-19 (3 × 10^-6 mol/L or 10^-5 mol/L) in calcium-free medium.

CONCLUSION: HEF-19 inhibited rabbit colonic smooth muscle contraction, probably through inhibiting opening of voltage-dependent Ca²⁺ channels. HEF-19 reduced inflow and intracellular release of Ca²⁺ ions.

The evaluation of otilonium bromide treatment in asian patients with irritable bowel syndrome

Background/Aims

Antispasmodics including otilonium bromide (OB) are recommended to treat irritable bowel syndrome (IBS). However, reports about OB experience in Asia is sparse. The purpose of present study was to provide the efficacy of OB in treating Asian IBS patients.

Methods

Overall, 117 IBS patients meeting Rome II criteria were enrolled in an 8-week, double-blind, active-controlled and single center trial. Randomized participants received either OB 40 mg or mebeverine 100 mg 3 doses daily. The primary endpoints were to evaluate the net changes of abdominal pain/discomfort frequency score (APDFS) and safety profile, while the secondary endpoints were to assess the changes in abdominal pain/discomfort intensity, flatulence, abdominal bloating, satisfied stool frequency etc.

Results

Finally, 49 OB and 52 mebeverine subjects were eligible for efficacy analysis. Compared to baselines in per protocol populations, the reduced APDFSs in OB and mebeverine were 0.55 ± 1.20 (P = 0.011) and 0.37 ± 1.11 (P = 0.042), respectively, to show similarly reduced scores. The most reported side effects included dry mouth, nausea and dizziness. Besides, the improved APDFSs at 4th week visit, final alleviations in abdominal pain intensity, flatulence, abdominal bloating and satisfied stool frequency with global assessments filled by both patients and investigators were significantly achieved by both treatments, and OB was not inferior to mebeverine in treating these parameters.

Conclusions

In Orientals, OB is as effective as mebeverine for alleviating IBS symptoms in terms of abdominal pain, flatulence, abdominal bloating etc. However, obvious side effects are also observed. A large-scaled trial and post-marketing surveillance are recommended to confirm its efficacy and safety.

Bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder. The role of pharmacotherapy for IBS is limited and focused mainly on symptom control.

OBJECTIVES

The objective of this systematic review was to evaluate the efficacy of bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome.

SEARCH STRATEGY

Computer assisted structured searches of MEDLINE, EMBASE, The Cochrane library, CINAHL and PsychInfo were conducted for the years 1966-2009. An updated search in April 2011 identified 10 studies which will be considered for inclusion in a future update of this review.

SELECTION CRITERIA

Randomized controlled trials comparing bulking agents, antispasmodics or antidepressants with a placebo treatment in patients with irritable bowel syndrome aged over 12 years were considered for inclusion. Only studies published as full papers were included. Studies were not excluded on the basis of language. The primary outcome had to include improvement of abdominal pain, global assessment or symptom score.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from the selected studies. Risk Ratios (RR) and Standardized Mean Differences (SMD) with 95% confidence intervals (CI) were calculated. A proof of practice analysis was conducted including sub-group analyses for different types of  bulking agents, spasmolytic agents or antidepressant medication. This was followed by a proof of principle analysis where only the studies with adequate allocation concealment were included.

MAIN RESULTS

A total of 56 studies (3725 patients) were included in this review. These included 12 studies of bulking agents (621 patients), 29 of antispasmodics (2333 patients), and 15 of antidepressants (922 patients). The risk of bias was low for most items. However, selection bias is unclear for many of the included studies because the methods used for randomization and allocation concealment were not described. No beneficial effect for bulking agents over placebo was found for improvement of abdominal pain (4 studies; 186 patients; SMD 0.03; 95% CI -0.34 to 0.40; P = 0.87), global assessment (11 studies; 565 patients; RR 1.10; 95% CI 0.91 to 1.33; P = 0.32) or symptom score (3 studies; 126 patients SMD -0.00; 95% CI -0.43 to 0.43; P = 1.00). Subgroup analyses for insoluble and soluble fibres also showed no statistically significant benefit. Separate analysis of the studies with adequate concealment of allocation did not change these results. There was a beneficial effect for antispasmodics over placebo for improvement of abdominal pain (58% of antispasmodic patients improved compared to 46% of placebo; 13 studies; 1392 patients; RR 1.32; 95% CI 1.12 to 1.55; P < 0.001; NNT = 7), global assessment (57% of antispasmodic patients improved compared to 39% of placebo; 22 studies; 1983 patients; RR 1.49; 95% CI 1.25 to 1.77; P < 0.0001; NNT = 5) and symptom score (37% of antispasmodic patients improved compared to 22% of placebo; 4 studies; 586 patients; RR 1.86; 95% CI 1.26 to 2.76; P < 0.01; NNT = 3). Subgroup analyses for different types of antispasmodics found statistically significant benefits for cimteropium/ dicyclomine, peppermint oil, pinaverium and trimebutine. Separate analysis of the studies with adequate allocation concealment found a significant benefit for improvement of abdominal pain. There was a beneficial effect for antidepressants over placebo for improvement of abdominal pain (54% of antidepressants patients improved compared to 37% of placebo; 8 studies; 517 patients; RR 1.49; 95% CI 1.05 to 2.12; P = 0.03; NNT = 5), global assessment (59% of antidepressants patients improved compared to 39% of placebo; 11 studies; 750 patients; RR 1.57; 95% CI 1.23 to 2.00; P < 0.001; NNT = 4) and symptom score (53% of antidepressants patients improved compared to 26% of placebo; 3 studies; 159 patients; RR 1.99; 95% CI 1.32 to 2.99; P = 0.001; NNT = 4). Subgroup analyses showed a statistically significant benefit for selective serotonin releasing inhibitors (SSRIs) for improvement of  global assessment and for tricyclic antidepressants (TCAs) for improvement of abdominal pain and symptom score. Separate analysis of studies with adequate allocation concealment found a significant benefit for improvement of symptom score and global assessment. Adverse events were not assessed as an outcome in this review.

AUTHORS' CONCLUSIONS

There is no evidence that bulking agents are effective for treating IBS.  There is evidence that antispasmodics are effective for the treatment of IBS. The individual subgroups which are effective include: cimetropium/dicyclomine, peppermint oil, pinaverium and trimebutine. There is good evidence that antidepressants are effective for the treatment of IBS. The subgroup analyses for SSRIs and TCAs are unequivocal and their effectiveness may depend on the individual patient. Future research should use rigorous methodology and valid outcome measures.

The clinical significances of irritable bowel syndrome in Taiwan

BACKGROUND AND AIM

According to the Rome III definition, irritable bowel syndrome (IBS) has been a biopsychosocial dysfunction. We tried to know whether the IBS clinical manifestations were comparable to other countries.

METHOD

We have reviewed the IBS publications in Taiwan, thus its clinical significances are summarized and compared to others.

RESULTS

Among a selected population of paid physical checkup, the Rome I & II criteria defined prevalences were 17.5% and 22.1%, respectively without an observed female predominance. However, female was a factor leading to constipation predominant IBS (C-IBS). Taiwan IBS patients did excessively consume society resource in terms of physician visits and absenteeism. They also had more chance of cholecystectomy, whereas normal appendix was often found in case of appendectomy. Overlapping extra-colonic manifestations, e.g. dyspepsia and lower urinary tract symptoms were common. Helicobacter pylori infection and female gender were closely related to the coexisted dyspepsia. Various psychiatric disturbances were also confirmed here. Intestinal transit correlated well with bowel symptoms, e.g. slow in constipation but fast in diarrhea. Diminished cholinergic activity was observed among the C-IBS patients. Various agents including mebeverine, pinaverium, peppermint oil, smectitie and tegarserod did somewhat improve IBS symptoms. Unfortunately, the IBS knowledge was not well understood among the medical professionals.

CONCLUSIONS

IBS is common in Taiwan, its impacts on the society are similarly observed while female gender often results in severe impacts. Disordered motility and cholinergic nervous system are likely some of its pathogeneses. Current recommended treatments are effectively demonstrated.

A sensitive and specific liquid chromatography/tandem mass spectrometry method for determination of pinaverium bromide in human plasma: application to a pharmacokinetic study in healthy volunteers

A sensitive and specific method using liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS) for the determination of pinaverium bromide in human plasma was developed and validated. Pinaverium bromide and an internal standard (paclitaxel) were isolated from plasma samples by precipitating plasma, and determined by LC-MS/MS in multiple-reaction monitoring mode. The main metabolite of pinaverium bromide and endogenous substances in plasma did not show any interference. The calibration curve was linear over the plasma concentration range of 10.0-10000.0 pg/mL with a correlation coefficient of 0.9979. The relative standard derivations intra- and inter-day at 30.0, 300.0 and 8000.0 pg/mL in plasma were less than 15%. The absolute recoveries of pinaverium bromide and the internal standard were 99.7-111.7 and 106.2%, respectively. The lower limit of quantitation was 10 pg/mL. The analytical method was successfully applied to study the pharmacokinetics of pinaverium bromide tablets in healthy Chinese volunteers.

Asian motility studies in irritable bowel syndrome

Altered motility remains one of the important pathophysiologic factors in patients with irritable bowel syndrome (IBS) who commonly complain of abdominal pain and stool changes such as diarrhea and constipation. The prevalence of IBS has increased among Asian populations these days. Gastrointestinal (GI) physiology may vary between Asian and Western populations because of differences in diets, socio-cultural backgrounds, and genetic factors. The characteristics and differences of GI dysmotility in Asian IBS patients were reviewed. MEDLINE search work was performed including following terms, 'IBS,' 'motility,' 'transit time,' 'esophageal motility,' 'gastric motility,' 'small intestinal motility,' 'colonic motility,' 'anorectal function,' and 'gallbladder motility' and over 100 articles were categorized under 'esophagus,' 'stomach,' 'small intestine,' 'colon,' 'anorectum,' 'gallbladder,' 'transit,' 'motor pattern,' and 'effect of stressors.' Delayed gastric emptying, slow tansit in constipation predominant IBS patients, rapid transit in diarrhea predominant IBS patients, accelerated motility responses to various stressors such as meals, mental stress, or corticotrophin releasing hormones, and altered rectal compliance and altered rectal accomodation were reported in many Asian studies regarding IBS. Many conflicting results were found among these studies and there are still controversies to conclude these as unique features of Asian IBS patients. Multinational and multicenter studies are needed to be performed vigorously in order to elaborate characteristics as well as differences of altered motililty in Asian patients with IBS.

A systematic review of efficacy and tolerability of mebeverine in irritable bowel syndrome

We evaluated the efficacy and tolerability of mebeverine, a musculotropic antispasmodic agent, in irritable bowel syndrome (IBS) and compared its usual dosages by meta-analysis. Medical databases and all relevant literature were searched from 1965 to June 2009 for any placebo-controlled clinical trials of mebeverine, using search terms such as mebeverine, clinical trials, and IBS. Eight randomized trials met our criteria, including six trials that compared mebeverine with placebo and two that compared mebeverine tablets with capsules. These eight trials included 555 patients randomized to receive either mebeverine or placebo with 352 (63%) women and 203 (37%) men in all subtypes of IBS. The pooled relative risk (RR) for clinical improvement of mebeverine was 1.13 (95% CI: 0.59-2.16, P = 0.7056) and 1.33 (95% CI: 0.92-1.93, P = 0.129) for relief of abdominal pain. The efficacy of mebeverine 200 mg compared to mebeverine 135 mg indicated RRs of 1.12 (95% CI: 0.96-1.3, P = 0.168) for clinical or global improvement and 1.08 (95% CI: 0.87-1.34, P = 0.463) for relief of abdominal pain. Thus, mebeverine is mostly well tolerated with no significant adverse effects; however, its efficacy in global improvement of IBS is not statistically significant.

Neuro-immune interactions in inflammatory bowel disease and irritable bowel syndrome: future therapeutic targets

The gastro-intestinal tract is well known for its largest neural network outside the central nervous system and for the most extensive immune system in the body. Research in neurogastroenterology implicates the involvement of both enteric nervous system and immune system in symptoms of inflammatory bowel disease and irritable bowel syndrome. Since both disorders are associated with increased immune cell numbers, nerve growth and activation of both immune cells and nerves, we focus in this review on the involvement of immune cell-nerve interactions in inflammatory bowel disease and irritable bowel syndrome. Firstly, the possible effects of enteric nerves, especially of the nonadrenergic and noncholinergic nerves, on the intestinal immune system and their possible role in the pathogenesis of chronic intestinal inflammatory diseases are described. Secondly, the possible effects of immunological factors, from the innate (chemokines and Toll-like receptors) as well as the adaptive (cytokines and immunoglobulins) immune system, on gastro-intestinal nerves and its potential role in the development of inflammatory bowel disease and irritable bowel syndrome are reviewed. Investigations of receptor-mediated and intracellular signal pathways in neuro-immune interactions might help to develop more effective therapeutic approaches for chronic inflammatory intestinal diseases.

Mast cells and nerves tickle in the tummy: implications for inflammatory bowel disease and irritable bowel syndrome

Mast cells are well known as versatile cells capable of releasing and producing a variety of inflammatory mediators upon activation and are often found in close proximity of neurons. In addition, inflammation leads to local activation of neurons resulting in the release neuropeptides, which also play an important immune modulatory role by stimulation of immune cells. In intestinal disorders like inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), the number of mast cells is known to be much higher than in the normal intestine. Moreover, both these disorders are also reported to be associated with alterations in neuropeptide content and in neural innervation. Mutual association between mast cells and enteric nerves has been demonstrated to be increased in pathophysiological conditions and contribute to spreading and amplification of the response in IBD and IBS. In this review the focus lies on studies appointed to the direct interaction between mast cells and nerves in IBD, IBS, and animal models for these disorders so far.

Irritable bowel syndrome in the 21st century: perspectives from Asia or South-east Asia

Asian irritable bowel syndrome (IBS) studies not only confirm the truth of this functional disorder but also describe the current disease situation of this continent, with its variable socioeconomic backgrounds. Most Asian community IBS prevalence is within 5-10%, regardless of gender or ethnic character. As well as meeting the main Rome II criteria, Asian IBS subjects also have many minor symptoms. Thus this recommendation remains useful to diagnose Asian IBS. Also, female patients commonly express constipation-predominant (C-) symptoms. Extra-colonic symptoms are common in Asia, for example dyspepsia, insomnia and irritable urinary bladder. Asian IBS subjects do experience psychological disturbances including anxiety, depression, agoraphobia and neuroticism. Accordingly, their quality of life is poor and there is absenteeism leading to excessive physician visits. Abnormal gut motor and sensory functions have been indicated among the Asian IBS subjects. Now, there is evidence of altered colonic neuroimmune function leading to gut hypersensitivity and dysmotility. An Asia-Pacific trial also confirmed tegaserod efficacy on female C-IBS subjects. More than 90% of nurses have very limited IBS knowledge, and are unable even to explain it clearly. In conclusion, Western recommended criteria clearly diagnose Asian IBS and many factors are mutual leading to IBS. Current IBS treatments remain useful but additional reeducation for medical professionals appears to be needed.

Actions of R- and S-verapamil and nifedipine on rat vascular and intestinal smooth muscle

1 We have investigated the actions of the calcium entry blockers nifedipine, R-verapamil and S-verapamil in rat aorta, colon and vas deferens. 2 In aorta and colon, these agents produced concentration-dependent relaxations of KCl (80 mM)-induced contractions. In both tissues, the order of potency was nifedipine > S-verapamil > R-verapamil. However, nifedipine showed selectivity for aorta (potency ratio, colon/aorta: 4.36), S-verapamil showed no selectivity (0.62), but R-verapamil showed selectivity for colon (0.19). 3 In prostatic portions of rat vas deferens, nifedipine (10 microM) abolished the contraction to a single electrical stimulus, but R- and S-verapamil were without effect. In epididymal portions of rat vas deferens, R- and S-verapamil inhibited alpha1-adrenoceptor-mediated contractions to a single electrical stimulus at concentrations of 10 microM and above. 4 In conclusion, R-verapamil may prove useful as an intestinal selective calcium entry blocker in the treatment of intestinal disease with a hypermotility component, e.g. irritable bowel syndrome.

Analysis of factors that determine the compliance of rat jejunum to distension in vivo

Distension of the intestine is commonly used to elicit reflex responses at other sites in the gastrointestinal tract, and also to evaluate pain of intestinal origin. The sensory neurones, that initiate the reflexes or pain responses, react to the forces generated in the wall of the intestine. Thus, the responses of the intestine at the site of distension, particularly changes in contractile activity, influence the signals from the gut. In the present work we have analysed the relationship between distension and pressure changes in the jejunum of the rat, in vivo. Isovolumic distension for 5 min caused an initial pressure increase which declined quickly in the first 30 s, and then declined more slowly. Phasic pressure increases were superimposed on the baseline pressure change. Hexamethonium blocked the phasic pressure increases, whereas the initial rapid and subsequent slower pressure decline during distension persisted. Inhibition of nitric oxide synthase (NOS) increased intraluminal pressure and caused increased frequency and irregularity of phasic pressure increases. However, the decline in jejunal pressure during distension was not changed by inhibition of NOS. The pressure decline during isovolumic distension was similar whether saline or paraffin oil were used to distend the intestine, indicating that the decline was not due to increased hydrostatic pressure causing water and electrolyte to cross the mucosal epithelium from the lumen to the intestinal interstitium. Hyoscine had no significant effect on the pressure profile when the intestine was distended. However, when the systemic or the local circulation of the jejunum was infused with nicardipine, the pressure that was achieved during isovolumic distension was less, although the rate of change in pressure during the slow decline was similar. It is concluded that distension evokes phasic pressure increases in the jejunum, that are nerve-mediated, and increases the tension in the wall through a stretch-activated increase in contractile force generated by the circular muscle. The decline in pressure during maintained distension is primarily a consequence of visco-elastic properties of the wall of the intestine.

Effect of pinaverium bromide on stress-induced colonic smooth muscle contractility disorder in rats

AIM

To investigate the effect of pinaverium bromide, a L-type calcium channel blocker with selectivity for the gastrointestinal tract on contractile activity of colonic circular smooth muscle in normal or cold-restraint stressed rats and its possible mechanism.

METHODS

Cold-restraint stress was conducted on rats to increase fecal pellets output. Each isolated colonic circular muscle strip was suspended in a tissue chamber containing warm oxygenated Tyrode-Ringer solution. The contractile response to ACh or KCl was measured isometrically on ink-writing recorder. Incubated muscle in different concentrations of pinaverium and the effects of pinaverium were investigated on ACh or KCl-induced contraction. Colon smooth muscle cells were cultured from rats and (Ca(2+))(i) was measured in cell suspension using the Ca(2+) fluorescent dye fura-2/AM.

RESULTS

During stress, rats fecal pellet output increased 61 % (P<0.01). Stimulated with ACh or KCl, the muscle contractility was higher in stress than that in control. Pinaverium inhibited the increment of (Ca(2+))(i) and the muscle contraction in response to ACh or KCl in a dose dependent manner. A significant inhibition of pinaverium to ACh or KCl induced (Ca(2+))(i) increment was observed at 10(-6) mol/L. The IC(50) values for inhibition of ACh induced contraction for the stress and control group were 1.66X10(-6) mol/L and 0.91X10(-6) mol/L, respectively. The IC(50) values for inhibition of KCl induced contraction for the stress and control group were 8.13X10(-7) mol/L and 3.80X10(-7) mol/L, respectively.

CONCLUSION

Increase in (Ca(2+))(i) of smooth muscle cells is directly related to the generation of contraction force in colon. L-type Ca(2+) channels represent the main route of Ca(2+) entry. Pinaverium inhibits the calcium influx through L-type channels; decreases the contractile response to many kinds of agonists and regulates the stress-induced colon hypermotility.