Treatment of abdominal pain in irritable bowel syndrome

Spinal cord injury-induced neurogenic bowel: A role for host-microbiome interactions in bowel pain and dysfunction

Background and aims

Spinal cord injury (SCI) affects roughly 300,000 Americans with 17,000 new cases added annually. In addition to paralysis, 60% of people with SCI develop neurogenic bowel (NB), a syndrome characterized by slow colonic transit, constipation, and chronic abdominal pain. The knowledge gap surrounding NB mechanisms after SCI means that interventions are primarily symptom-focused and largely ineffective. The goal of the present studies was to identify mechanism(s) that initiate and maintain NB after SCI as a critical first step in the development of evidence-based, novel therapeutic treatment options.

Methods

Following spinal contusion injury at T9, we observed alterations in bowel structure and function reflecting key clinical features of NB. We then leveraged tissue-specific whole transcriptome analyses (RNAseq) and fecal 16S rRNA amplicon sequencing in combination with histological, molecular, and functional (Ca2+ imaging) approaches to identify potential mechanism(s) underlying the generation of the NB phenotype.

Results

In agreement with prior reports focused on SCI-induced changes in the skin, we observed a rapid and persistent increase in expression of calcitonin gene-related peptide (CGRP) expression in the colon. This is suggestive of a neurogenic inflammation-like process engaged by antidromic activity of below-level primary afferents following SCI. CGRP has been shown to disrupt colon homeostasis and negatively affect peristalsis and colon function. As predicted, contusion SCI resulted in increased colonic transit time, expansion of lymphatic nodules, colonic structural and genomic damage, and disruption of the inner, sterile intestinal mucus layer corresponding to increased CGRP expression in the colon. Gut microbiome colonization significantly shifted over 28 days leading to the increase in Anaeroplasma, a pathogenic, gram-negative microbe. Moreover, colon specific vagal afferents and enteric neurons were hyperresponsive after SCI to different agonists including fecal supernatants.

Conclusions

Our data suggest that SCI results in overexpression of colonic CGRP which could alter colon structure and function. Neurogenic inflammatory-like processes and gut microbiome dysbiosis can also sensitize vagal afferents, providing a mechanism for visceral pain despite the loss of normal sensation post-SCI. These data may shed light on novel therapeutic interventions targeting this process to prevent NB development in patients.

Probiotic-Associated Central Venous Catheter Bloodstream Infections Lead to Increased Mortality in the ICU

OBJECTIVES

To determine the occurrence rate and impact on patient outcomes of probiotic-associated central venous catheter bloodstream infections in the ICU.

DESIGN

Retrospective observational cohort study.

SETTING

The cohort was gathered using HCA Healthcare's data warehouse.

PATIENTS

Adult patients with central venous catheters in the ICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Blood culture data were used to determine whether an infection had occurred with an organism contained in an administered probiotic. Eighty-six probiotic-associated central venous catheter bloodstream infections were identified among the 23,015 patient cohort who received probiotics (0.37%). The number needed to harm was 270. Zero infections were found in the cohort that did not receive probiotics. Patients who contracted a probiotic infection had increased mortality (odds ratio, 2.23; 1.30-3.71; p < 0.01). Powder formulations had an increased rate of infection compared with nonpowder formulations (0.76% vs 0.33%; odds ratio, 2.03; 1.05-3.95; p = 0.04).

CONCLUSIONS

Probiotic administration is associated with a substantial rate of probiotic-associated bloodstream infection in ICU patients with central venous catheters in place. Probiotic-associated bloodstream infections result in significantly increased mortality. Powder formulations cause bloodstream infections more frequently than nonpowder formulations. In ICU patients with central venous catheters, the risks of probiotic-associated central venous catheter bloodstream infection and death outweigh any potential benefits of probiotic administration.

Targeting the endocannabinoid system for the treatment of abdominal pain in irritable bowel syndrome

The management of visceral pain in patients with disorders of gut-brain interaction, notably irritable bowel syndrome, presents a considerable clinical challenge, with few available treatment options. Patients are increasingly using cannabis and cannabinoids to control abdominal pain. Cannabis acts on receptors of the endocannabinoid system, an endogenous system of lipid mediators that regulates gastrointestinal function and pain processing pathways in health and disease. The endocannabinoid system represents a logical molecular therapeutic target for the treatment of pain in irritable bowel syndrome. Here, we review the physiological and pathophysiological functions of the endocannabinoid system with a focus on the peripheral and central regulation of gastrointestinal function and visceral nociception. We address the use of cannabinoids in pain management, comparing them to other treatment modalities, including opioids and neuromodulators. Finally, we discuss emerging therapeutic candidates targeting the endocannabinoid system for the treatment of pain in irritable bowel syndrome.

Diet and Pediatric Functional Gastrointestinal Disorders in Mediterranean Countries

Background: The increased intake of FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyol) rich foods has been suggested as a possible trigger of functional gastrointestinal disorders (FGIDs). Despite the high FODMAP content, the Mediterranean diet (MD) appears to have beneficial effects on health. Our aim was to evaluate whether the prevalence of FGIDs in different Mediterranean countries may be influenced by FODMAP consumption and adherence to the MD. Methods: A school-based, cross-sectional, multicenter study was performed in six countries in the Mediterranean area: Croatia, Greece, Israel, Italy, Macedonia, and Serbia. Subjects 4-18 years were examined in relation to their eating habits and the presence of FGIDs, using Rome IV criteria, 3-day food diaries and Mediterranean Diet Quality Index in Children and Adolescents (KIDMED) questionnaires. Results: We enrolled 1972 subjects between 4 and 9 years old (Group A), and 2450 subjects between 10 and 18 years old (Group B). The overall prevalence of FGIDs was 16% in Group A and 26% in Group B. FODMAP intake was significantly different among countries for both age groups. In both groups, no significant association was found between FGIDs and FODMAPs. Adherence to the MD in all countries was intermediate, except for Serbia, where it was low. In both groups, we found a statistically significant association between FGIDs and the KIDMED score (Group A: OR = 0.83, p < 0.001; Group B: OR = 0.93, p = 0.005). Moreover, a significant association was found between the KIDMED score and functional constipation (Group A: OR = 0.89, p = 0.008; Group B: OR = 0.93, p = 0.010) and postprandial distress syndrome (Group A: OR = 0.86, p = 0.027; Group B: OR = 0.88, p = 0.004). Conclusions: Our data suggest that the prevalence of FGIDs in the Mediterranean area is not related to FODMAP consumption, whereas adherence to the MD seems to have a protective effect.

Belgian consensus on irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is characterised by recurrent abdominal pain related to defaecation or associated with altered stool frequency or consistency. Despite its prevalence, major uncertainties in the diagnostic and therapeutic management persist in clinical practice.

METHODS

A Delphi consensus was conducted by 20 experts from Belgium, and consisted of literature review and voting process on 78 statements. Grading of recommendations, assessment, development and evaluation criteria were applied to evaluate the quality of evidence. Consensus was defined as > 80 % agreement.

RESULTS

Consensus was reached for 50 statements. The Belgian consensus agreed as to the multifactorial aetiology of IBS. According to the consensus abdominal discomfort also represents a cardinal symptom, while bloating and abdominal distension often coexist. IBS needs subtyping based on stool pattern. The importance of a positive diagnosis, relying on history and clinical examination is underlined, while additional testing should remain limited, except when alarm features are present. Explanation of IBS represents a crucial part of patient management. Lifestyle modification, spasmolytics and water-solube fibres are considered first-line agents. The low FODMAP diet, selected probiotics, cognitive behavioural therapy and specific treatments targeting diarrhoea and constipation are considered appropriate. There is a consensus to restrict faecal microbiota transplantation and gluten-free diet, while other treatments are strongly discouraged.

CONCLUSIONS

A panel of Belgian gastroenterologists summarised the current evidence on the aetiology, symptoms, diagnosis and treatment of IBS with attention for the specificities of the Belgian healthcare system.

Electrocardiogram Before Tricyclic Antidepressant Use: Minimal Impact in Pediatric Functional Gastrointestinal Disorders

OBJECTIVES

The aim of this study was to determine the effect of electrocardiogram (ECG) findings on the initiation of tricyclic antidepressants (TCAs) for functional gastrointestinal disorders (FGIDs) and to evaluate cardiac outcomes related to low dose TCA use.

METHODS

We performed a retrospective chart review of all pediatric outpatients at a tertiary pediatric hospital with an ECG ordered by a pediatric gastroenterologist when considering initiation of a TCA between January 2011 and February 2018. We collected demographics, previous cardiovascular testing results, TCA dosing, and pertinent outcomes, including cardiology referrals, emergency department, and hospital admissions, and death during the study period. All ECGs were reviewed for corrected QT (QTc) interval, heart rate, and other abnormalities.

RESULTS

Of 233 patients with screening ECGs, most (84.1%) were prescribed a TCA. Functional abdominal pain or dyspepsia account for 82.0% of diagnoses. Initial TCA dosing of amitriptyline varied widely, 10-50 mg/day, and the dose was not associated with QTc intervals. TCAs were not started in only 1.7% (4/233) due to ECG results. A significant ECG abnormality prompting cardiology referral was found in eight (3.4%) with a prolonged QTc interval in one (0.4%). In 10.7% (25/233) of patients, screening ECG was obtained despite available ECG in the chart. No deaths and no emergency department or hospital visits for arrhythmia or drug overdose occurred.

CONCLUSION

Screening ECGs infrequently influence TCA initiation and may lead to increased resource utilization. The overall frequency of cardiology referral due to ECG results is low. Serious adverse cardiac events are unlikely with low dose TCA administration.

Probiotic VSL#3 Treatment Reduces Colonic Permeability and Abdominal Pain Symptoms in Patients With Irritable Bowel Syndrome

Background: Little is known regarding the clinical impact of treatment and treatment duration of probiotic VSL#3 on gut and microbiome function in irritable bowel syndrome (IBS). As part of a safety trial, we assessed the effect of VSL#3 treatment duration on abdominal pain, stooling, gut permeability, microbiome composition and function.

Methods: Adults with IBS were randomized into an open label trial to receive the probiotic VSL#3 for 4 or 8 weeks. Adverse events, abdominal pain, and stooling patterns were recorded daily. Gut permeability, fecal bile acid levels, and microbiome composition were profiled at baseline and after treatment.

Results: Fifteen subjects completed the trial (4-week: n = 8; 8-week: n = 7). Number of pain episodes decreased in both groups (P = 0.049 and P = 0.034; 4- vs. 8-week, respectively). Probiotic organisms contained in VSL#3 were detected in feces by whole shotgun metagenomic sequencing analysis and relative abundances of Streptococcus thermophilus, Bifidobacterium animalis, Lactobacillus plantarum, and Lactobacillus casei subsp. paraccasei correlated significantly with improved abdominal pain symptoms and colonic permeability at study completion. Although abdominal pain correlated significantly with the detection of probiotic species at study completion, a composite view of gut microbiome structure showed no changes in community diversity or composition after VSL#3 treatment.

Conclusions: Probiotic organisms identified in stool correlated significantly with improvement in colonic permeability and clinical symptoms, prompting future studies to investigate the mechanistic role of VSL#3 and colonic permeability in IBS pathophysiology in a larger randomized controlled trial.

Clinical Trial Registration:www.clinicaltrials.gov, Identifier: NCT00971711.

Efficacy of Acupuncture in the Treatment of Chronic Abdominal Pain

Context

Abdominal pain is a widespread complaint and is one of the common reasons leading patients to seek medical care, either in emergency situations or with their primary providers. While acute abdominal pain is a better defined, usually surgical condition, chronic abdominal pain requires longer, typically lifelong, therapy. Chronic abdominal pain may also present with acute flares and complications. Here we review seminal and novel evidence discussing the use of acupuncture in the treatment of abdominal pain, indications, and conditions that may benefit from this approach.

Evidence Acquisition

Chronic abdominal pain is a common complaint causing significant morbidity and disability and has a hefty price tag attached. Recent studies show it may be prevalent in as much as 25% of the adult population. It is defined as three episodes of severe abdominal pain over the course of three months. Chronic abdominal pain could be the result of chronicity of acute pain or of chronic pain syndromes, most commonly IBD syndromes and IBS. While a plethora of treatments exists for both conditions, these treatments usually fall short of complete symptom control, and there is a need for complementary measures to curb disability and increase the quality of life in these patients. Acupuncture is a form of integrative medicine that has long been used in Chinese and traditional medicine, based on the rebalancing of the patient’s Qi, or Ying/Yang balance. It has been shown to be effective in treating several other conditions, and novel evidence may expand its use into other fields as well. Clinical trials studying acupuncture in chronic pain conditions have been promising, and recent evidence supports the use of abdominal pain in chronic abdominal pain conditions as well. Though not curative, acupuncture is a complementary approach that helps reduce symptoms and improved quality of life.

Conclusions

Chronic abdominal pain is a widespread condition, mostly affected by the IBS and IBD spectrum. Etiologies are still being studied for these conditions, and while novel treatment approaches are absolute game changers for these patients, many continue to experience some level of symptoms and disability. Acupuncture may provide further alleviation of these symptoms in select patients, thus improving quality of life, reducing disability, and saving healthcare dollars. It is a largely safe and inexpensive method that may significantly contribute to the quality of life of selected patients.

Dietary tryptophan depletion alters the faecal bacterial community structure of compulsive drinker rats in schedule-induced polydipsia

RATIONALE

Compulsive behaviour, present in different psychiatric disorders such as obsessive-compulsive disorder, schizophrenia and drug abuse, is associated with altered levels of serotonin (5-hydroxytryptamine, 5-HT). The gut microbiota regulates tryptophan (TRP) metabolism and may affect global 5-H synthesis in the enteric and central nervous systems, suggesting a possible involvement of gut microbiota in compulsive spectrum disorders.

OBJECTIVES

The present study investigated whether chronic TRP depletion by diet alters the faecal bacterial community profiles of compulsive versus non-compulsive rats in schedule-induced polydipsia (SIP). Peripheral plasma 5-HT and brain-derived neurotrophic factor (BDNF) levels were evaluated.

METHODS

Wistar rats were selected as High Drinkers (HD) or Low Drinkers (LD) according to their SIP behaviour and were fed for 14 days with either a TRP-free diet (T-) or a TRP-supplemented diet (T+). The faecal bacterial community structure was investigated with 16S rRNA gene-targeted denaturing gradient gel electrophoresis (DGGE) fingerprinting analysis.

RESULTS

Compulsive HD rats showed a lower bacterial diversity than LD rats, irrespectively of the diet. The TRP-depleted HD rats, the only group increasing compulsive licking in SIP, showed a reduction of bacterial evenness and a highly functionally organized community compared with the other groups, indicating that this bacterial community is more fragile to external changes due to the dominance of a low number of species. The chronic TRP depletion by diet effectively reduced peripheral plasma 5-HT levels in both HD and LD rats, while plasma BDNF levels were not altered.

CONCLUSIONS

These results highlight the possible implication of reduced microbial diversity in compulsive behaviour and the involvement of the serotonergic system in modulating the gut brain-axis in compulsive spectrum disorders.

Imipramine improves visceral sensation and gut barrier in rat models of irritable bowel syndrome

An impaired gut barrier, possibly leading to visceral hypersensitivity has been recently recognized to be one of the pivotal pathophysiology of irritable bowel syndrome (IBS). We previously showed that lipopolysaccharide (LPS), corticotropin-releasing factor (CRF), and repeated water avoidance stress (WAS) induce visceral hypersensitivity and colonic hyperpermeability via pro-inflammatory cytokine signaling (rat IBS models). Although the precise mechanisms of action are unclear, imipramine, a tricyclic antidepressant, improves IBS symptoms, and also has anticytokine properties. In this study, we hypothesized that imipramine improves the gut barrier to ameliorate IBS symptoms. To test this hypothesis, we determined its effects on visceral hypersensitivity and colonic hyperpermeability in rat IBS models. The visceral pain threshold in response to colonic balloon distention was electrophysiologically estimated by abdominal muscle contractions, and colonic permeability was measured by quantifying the absorbed Evans blue in colonic tissue in vivo. Subcutaneous imipramine injection (7, 20, 50 mg/kg) dose-dependently inhibited LPS-induced (1 mg/kg, subcutaneously) visceral hypersensitivity and colonic hyperpermeability. Imipramine also blocked these gastrointestinal (GI) changes induced by CRF (50 μg/kg, intraperitoneally) or repeated WAS (1 h daily for 3 days). Yohimbine (an α₂-adrenoceptors antagonist), sulpiride (a dopamine D₂ receptor antagonist), and naloxone hydrochloride (an opioid receptor antagonist) reversed these effects of imipramine in the LPS model. Therefore, imipramine may block GI changes in IBS via α₂-adrenoceptors, dopamine D₂, and opioid signaling. The improvement in the gut barrier resulting in inhibition of visceral pain is considered a valid mechanism of imipramine to ameliorate IBS symptoms.

Small Intestinal Bacterial Overgrowth Diagnosed by a Breath Test and Improved by Rifaximin in a Patient with Hepatic Encephalopathy and Alcoholic Liver Cirrhosis

A 66-year-old Japanese man was admitted to our hospital with grade 2 hepatic encephalopathy (HE). Abdominal computed tomography and laboratory examinations revealed decompensated liver cirrhosis. Intravenous administration of branched-chain amino acids immediately ameliorated the HE, and lactulose was initiated. However, a breath test revealed small intestinal bacterial overgrowth (SIBO); therefore, rifaximin was additionally initiated. The breath test was repeated after discharge, when no evidence of SIBO or overt HE was identified. This case suggested that a breath test is effective for the identification of SIBO and that the administration of a poorly absorbed antibiotic should be considered in SIBO-positive HE patients taking lactulose.

The Effect of Phloroglucinol in Patients With Diarrhea-predominant Irritable Bowel Syndrome: A Randomized, Double-blind, Placebo-controlled Trial

BACKGROUND/AIMS

We aim to evaluate the efficacy and safety of phloroglucinol in patients with diarrhea-predominant irritable bowel syndrome (IBS-D).

METHODS

Seventy-two patients with IBS-D who met Rome III criteria were 1:1 randomized in a parallel, double-blind design to receive phloroglucinol or placebo for 2 weeks. Patients were followed for 1 week after the end of treatment. The primary outcome was the proportion of responders, defined as those who answered "moderate or more of improvement" to the subject global assessment for at least 1 week of the 2-week treatment period. Secondary outcomes included the proportion of these patients during the 3-week period including 1 week of follow-up, IBS symptoms (abdominal pain/discomfort, diarrhea, urgency, mucus in stool, bloating, and passage of gas), stool frequency and consistency, and IBS quality of life (IBS-QOL).

RESULTS

The proportion of responders during 2-week treatment period tended to be higher in the phloroglucinol group than in the placebo group, although the difference did not reach statistical significance (55.6% vs 30.6%, P = 0.056). The proportion of responders during the 3-week period was significantly higher in the phloroglucinol group than in the placebo group (61.6% vs 30.6%, P = 0.013). Individual symptom scores, IBS-QOL, stool frequency and consistency tended to improve in the phloroglucinol group, but there were no statistical significances compared to those of the placebo group. No serious adverse events were reported in both groups.

CONCLUSIONS

Phloroglucinol could be a safe and beneficial option for the management of overall IBS symptoms in patients with IBS-D. Further large scaled studies are warranted.

Painful interactions: Microbial compounds and visceral pain

Visceral pain, characterized by abdominal discomfort, originates from organs in the abdominal cavity and is a characteristic symptom in patients suffering from irritable bowel syndrome, vulvodynia or interstitial cystitis. Most organs in which visceral pain originates are in contact with the external milieu and continuously exposed to microbes. In order to maintain homeostasis and prevent infections, the immune- and nervous system in these organs cooperate to sense and eliminate (harmful) microbes. Recognition of microbial components or products by receptors expressed on cells from the immune and nervous system can activate immune responses but may also cause pain. We review the microbial compounds and their receptors that could be involved in visceral pain development.

Effect of electroacupuncture at homotopic and heterotopic acupoints on abdominal pain in patients with irritable bowel syndrome: study protocol for a randomized controlled trial

BACKGROUND

Acupuncture has been widely applied in the clinic to treat irritable bowel syndrome (IBS), but the underlying mechanism remains unknown. Diffuse noxious inhibitory control (DNIC) is deficient in patients with IBS, which attenuates the systemic analgesic effect elicited by noxious stimulation that is remote from pain areas. Therefore, the aim of this study is to investigate the analgesic effect of electroacupuncture (EA) at homotopic or heterotopic acupoints on abdominal pain in patients with IBS.

METHODS/DESIGN

This study is a randomized, single-blinded, controlled, four-arm parallel trial. A total of 144 patients will be randomly assigned to four groups: a homotopic noxious stimulation group (group A), a homotopic innocuous stimulation group (group B), a heterotopic noxious stimulation group (group C), and a heterotopic innocuous stimulation group (group D). Each patient will receive 14 sessions of treatment, twice per week for 7 weeks. The primary outcome will be pain intensity measured with the visual analog scale. The secondary outcomes will include the IBS Symptom Severity Scale, IBS Quality of Life questionnaire, pain threshold (PT), and the Symptom Checklist-90 for psychological distress. The PT will be measured before and after every treatment. All other outcomes will be evaluated before the 1st treatment, after 7th and 14th treatment, and 3 months later during follow-up.

DISCUSSION

The aim of this study is to assess the analgesic effect of EA at homotopic (abdomen) acupoints and heterotopic (lower limb) acupoints on abdominal pain in patients with IBS, as well as the difference in analgesic effects between noxious and innocuous stimulation.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR-IPR-15006879 . Registered on 5 August 2015.

Chronic abdominal pain in irritable bowel syndrome - current and future therapies

INTRODUCTION

Irritable bowel syndrome (IBS) is a functional gut disorder that typically manifests in early adult years. One of the two major symptoms of the disease is chronic, visceral pain. The patients report pain as the most distressing symptom with the greatest impact on quality of life, challenging both to patients and healthcare providers. Areas covered: This review focuses on the pathophysiology of abdominal pain in IBS and describes current treatment possibilities. It also covers latest findings that may lead to novel pharmacological options in IBS pain management. Expert commentary: Pain is the main contributor to severity in IBS. Seeking pain alleviation is the most common reason that IBS sufferers consult with their physicians. Not all patients report being satisfied with available treatments for pain in IBS and there is a pressing need to find new, more efficient therapies for this syndrome.

Trends in Teenagers' Nonopiod Substance Exposures Reported to Poison Control Centers, 2010-2015

OBJECTIVE

To describe current trends in nonopioid substance exposures and associated outcomes among teenagers nationwide.

STUDY DESIGN

In this cross-sectional study, we used 2010-2015 data from the American Association of Poison Control Centers' National Poison Data System and Poisson tests to document trends in the rate of calls to poison control centers involving adolescents stratified by sex, exposures by substance category, proportion of intentional exposures, and severity of exposures.

RESULTS

The number of calls per 1000 persons increased from 5.7 to 6.8 for teenage girls and decreased from 4.7 to 4.3 for boys. Reported exposures to prescription and over-the-counter medications and illicit street drugs increased between 24% and 73%, and reported opioid exposures decreased by 16%. Among teenage girls, intentional exposures increased from 57% to 68%, with cases increasingly managed in health care facilities and more likely to result in worse health outcomes.

CONCLUSIONS

The increase in intentional nonopioid substance exposures among teenage girls, with serious and potentially life-threatening consequences, is a matter of serious concern. Similar trends were not observed among teenage boys.

[Clinical Approach to Abdominal Pain as Functional Origin]

Abdominal pain is a common symptom that patients refer to a hospital. Organic causes should be differentiated in patients with abdominal pain and treatment should be administered in accordance with the causes. A meticulous history taking and physical examination are highly useful in making a diagnosis, and blood tests, imaging modalities, and endoscopy are useful for confirming diagnosis. However, in many cases, patients have functional disorders with no obvious abnormal findings obtained even if many diagnostic tests are performed. Patients with functional disorders usually complain the vague abdominal pain located in the center and other portions of the abdominal area. Although the most representative disease is irritable bowel syndrome, functional abdominal pain syndrome is currently researched as a new disease entity of functional abdominal pain. As various receptors related to functional abdominal pain have been discovered, drugs associated with those receptors are used to treat the disorders, and additional new drugs are vigorously developed. In addition, medical therapy with pharmacological or non-pharmacological psychiatric treatment is effective for treating functional abdominal pain.

Hwangryunhaedok-tang induces the depolarization of pacemaker potentials through 5-HT3 and 5-HT4 receptors in cultured murine small intestine interstitial cells of Cajal

AIM

To investigate the effects of a water extract of Hwangryunhaedok-tang (HHTE) on the pacemaker potentials of mouse interstitial cells of Cajal (ICCs).

METHODS

We dissociated ICCs from small intestines and cultured. ICCs were immunologically identified using an anti-c-kit antibody. We used the whole-cell patch-clamp configuration to record the pacemaker potentials generated by cultured ICCs under the current clamp mode (I = 0). All experiments were performed at 30 °C-32 °C

RESULTS

HHTE dose-dependently depolarized ICC pacemaker potentials. Pretreatment with a 5-HT₃ receptor antagonist (Y25130) or a 5-HT₄ receptor antagonist (RS39604) blocked HHTE-induced pacemaker potential depolarizations, whereas pretreatment with a 5-HT₇ receptor antagonist (SB269970) did not. Intracellular GDPβS inhibited HHTE-induced pacemaker potential depolarization and pretreatment with a Ca²⁺-free solution or thapsigargin abolished the pacemaker potentials. In the presence of a Ca²⁺-free solution or thapsigargin, HHTE did not depolarize ICC pacemaker potentials. In addition, HHTE-induced pacemaker potential depolarization was unaffected by a PKC inhibitor (calphostin C) or a Rho kinase inhibitor (Y27632). Of the four ingredients of HHT, Coptidis Rhizoma and Gardeniae Fructus more effectively inhibited pacemaker potential depolarization.

CONCLUSION

These results suggest that HHTE dose-dependently depolarizes ICC pacemaker potentials through 5-HT₃ and 5-HT₄ receptors via external and internal Ca²⁺ regulation and via G protein-, PKC- and Rho kinase-independent pathways.

The neurokinin-2 receptor antagonist ibodutant improves overall symptoms, abdominal pain and stool pattern in female patients in a phase II study of diarrhoea-predominant IBS

BACKGROUND

Tachykinins have been implicated in the pathophysiology of IBS with diarrhoea (IBS-D). Our aim was to study the efficacy and safety of ibodutant, a selective neurokinin-2 (NK2) receptor antagonist, in patients with IBS-D.

METHODS

This multinational double-blind, placebo-controlled study recruited 559 patients with IBS-D according to Rome III criteria. After a 2-week treatment-free run-in, patients were randomised to ibodutant 1 mg, 3 mg, 10 mg or placebo once daily for eight consecutive weeks. Responders were those with a combined response of satisfactory relief (weekly binary question yes/no) of overall IBS symptoms and abdominal pain/discomfort on ≥75% weeks (primary end point). Secondary end points included abdominal pain and stool pattern. Data were also analysed according to US Food and Drug Administration (FDA)-approved interim end points (improvement of pain and stool consistency). Safety was assessed by monitoring adverse events and laboratory tests. Prespecified statistical analysis involved the whole group as well as gender subgroups.

RESULTS

Demographics and baseline characteristics were comparable for all treatment arms. In the overall population, responsiveness tended to increase with escalating ibodutant doses. In the prespecified analysis by gender, ibodutant 10 mg demonstrated significant superiority over placebo in females (p=0.003), while no significant effect occurred in males. This was confirmed for secondary end points and for the responder analysis according to FDA-approved end points. The tolerability and safety of ibodutant was excellent at all doses.

CONCLUSIONS

Ibodutant showed dose-dependent efficacy response in IBS-D, reaching statistical significance at the 10 mg dose in female patients. The safety and tolerability profile of ibodutant was similar to placebo.

TRIAL REGISTRATION NUMBER

NCT01303224.

Treatment of Functional Abdominal Pain With Antidepressants: Benefits, Adverse Effects, and the Gastroenterologist's Role

OBJECTIVES

Pediatric functional abdominal pain is often treated with tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs). The aim is investigating antidepressant use for treatment efficacy, correlation of response to psychiatric factors, and impact of adverse effects in regard to physicians' prescribing patterns.

METHODS

Retrospective review (2005-2013) children (5-21 years old) with functional abdominal pain treated with SSRI or TCA. Of the 531 cases with functional abdominal pain, 192 initiated SSRIs or TCAs while followed by gastroenterology. Charts reviewed for symptoms, adverse effects, and response: decreased pain or increased daily functioning.

RESULTS

Sixty-three of 84 (75%) SSRI patients improved, 56 of 92 (61%) TCA patients improved (P = 0.03). Logistic regression controlling for psychiatric factors: SSRI remained significant over TCA (P = 0.04). Thirty-two of 67 (48%) patients with constipation received TCAs and 26 of 45 (58%) patients with diarrhea received SSRIs (P = 0.64). Three SSRI patients reported gastrointestinal effects, all diarrheal-type symptoms, and 2 TCA patients reported gastrointestinal effects, both constipation, in all it led to discontinuation. Thirteen (29%) of diarrheal-type patients reported adverse effects causing discontinuation as compared to 7 (8%) in the constipation group (P = .01). Twenty-one (25%) SSRI patients reported adverse effects with 5 (6%) mood disturbances. Twenty (22%) TCA patients reported adverse effects, 13 (14%) with mood disturbances (P = .07). Overall, 12 (14%) SSRI patients discontinued medication due to adverse effects, whereas 16 (17%) TCA patients (P = 0.24) did.

CONCLUSIONS

Patients had significantly greater response to SSRIs than TCAs, remaining significant after controlling for psychiatric factors. Little significance is given to patient's associated gastrointestinal symptoms, frequently resulting in adverse effects and termination of medication.

Neurotransmitters: The Critical Modulators Regulating Gut-Brain Axis

Neurotransmitters, including catecholamines and serotonin, play a crucial role in maintaining homeostasis in the human body. Studies on these neurotransmitters mainly revolved around their role in the "fight or flight" response, transmitting signals across a chemical synapse and modulating blood flow throughout the body. However, recent research has demonstrated that neurotransmitters can play a significant role in the gastrointestinal (GI) physiology. Norepinephrine (NE), epinephrine (E), dopamine (DA), and serotonin have recently been a topic of interest because of their roles in the gut physiology and their potential roles in GI and central nervous system pathophysiology. These neurotransmitters are able to regulate and control not only blood flow, but also affect gut motility, nutrient absorption, GI innate immune system, and the microbiome. Furthermore, in pathological states, such as inflammatory bowel disease (IBD) and Parkinson's disease, the levels of these neurotransmitters are dysregulated, therefore causing a variety of GI symptoms. Research in this field has shown that exogenous manipulation of catecholamine serum concentrations can help in decreasing symptomology and/or disease progression. In this review article, we discuss the current state-of-the-art research and literature regarding the role of neurotransmitters in regulation of normal GI physiology, their impact on several disease processes, and novel work focused on the use of exogenous hormones and/or psychotropic medications to improve disease symptomology. J. Cell. Physiol. 232: 2359-2372, 2017. © 2016 Wiley Periodicals, Inc.

Chemical profiles and pharmacological activities of Chang-Kang-Fang, a multi-herb Chinese medicinal formula, for treating irritable bowel syndrome

ETHNOPHARMACOLOGICAL RELEVANCE

Chang-Kang-Fang formula (CKF), a multi-herb traditional Chinese medicinal formula, has been clinically used for treatment of irritable bowel syndrome (IBS). The mechanisms of CKF for treating IBS and the components that are responsible for the activities were still unknown.

AIM OF THE STUDY

To investigate the chemical profiles and effects of CKF on IBS model.

MATERIALS AND METHODS

The chemical profiles of CKF were investigated by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-Q/TOF-MS/MS). On colon irritation induced rat neonates IBS model, the influence of CKF on neuropeptides, including substance P (SP), calcitonin gene-related peptide (CGRP), vasoactive intestinal polypeptide (VIP) and 5-hydroxytryptamine (5-HT), were measured by ELISA, and the effect on intestinal sensitivity was assessed based on the abdominal withdrawal reflex (AWR) scores. In addition, the activities of CKF against acetic acid-induced nociceptive responses and prostigmin methylsulfate triggered intestinal propulsion in mice were also evaluated.

RESULTS

80 components were identified or tentatively assigned from CKF, including 11 alkaloids, 20 flavanoids, 4 monoterpenoids, 9 iridoid glycoside, 9 phenylethanoid glycosides, 10 chromones, 7 organic acid, 3 coumarins, 2 triterpene and 5 other compounds. On IBS rat model, CKF was observed to reduce AWR scores and levels of SP, CGRP, VIP and 5-HT. Moreover, CKF reduced the acetic acid-induced writhing scores at all dosages and reduced the intestinal propulsion ration at dosage of 7.5 and 15.0g/kg/d.

CONCLUSIONS

CKF could alleviate the symptoms of IBS by modulating the brain-gut axis through increasing the production of neuropeptides such as CGRP, VIP, 5-HT and SP, releasing pain and reversing disorders of intestinal propulsion. Berberine, paeoniflorin, acteoside, flavonoids and chromones may be responsible for the multi-bioactivities of CKF.

Downregulation of the spinal NMDA receptor NR2B subunit during electro-acupuncture relief of chronic visceral hyperalgesia

The involvement of spinal NR2B, a N-methyl-D-aspartate (NMDA) receptor subunit, in the therapeutic effect of electro-acupuncture (EA) on chronic visceral hyperalgesia was investigated. Chronic visceral hyperalgesia was induced using an irritable bowel syndrome (IBS) model in rats. Graded colorectal distention (CRD) stimuli at strengths of 20, 40, 60 and 80 mmHg were applied, and behavioral tests were performed to measure the abdominal withdrawal reflex (AWR) in response to the CRD stimuli and assess the severity of the visceral hyperalgesia. Rats were randomly divided into four groups: normal intact (control) group, IBS model (model) group, EA-treated IBS rats (EA) group and sham EA-treated IBS rats (sham EA) group. For the EA treatment, electric stimuli were applied through needles inserted into two acupoints [Zu-san-li (ST-36) and Shang-ju-xu (ST-37)] in both hind limbs, while the sham EA treatment consisted of only the insertion of needles into these same acupoints without an application of electric stimuli. Our results showed that AWR scores of the model group responding to CRD stimuli of 20, 40, 60 and 80 mmHg were significantly increased. These increased scores subsequently decreased following EA treatment (P < 0.05) compared with those for the other groups. The expression of NR2B in the superficial laminae (SDH, laminae I and II), nucleus proprius (NP, laminae III and IV), neck of the dorsal horn (NECK, laminae V and VI) and central canal region (lamina X) at thoracolumbar (T13-L2) and lumbosacral (L6-S2) segmental level significantly increased in the model group versus the control group (P < 0.05) and significantly decreased after EA treatment (P < 0.05). There were no significant changes in neither AWR scores nor expression of the NR2B subunit in these spinal regions after the sham EA treatment. These results confirm that EA can relieve chronic visceral hyperalgesia in IBS model rats and suggest that such an effect is possibly mediated through the downregulation of the NR2B subunits of NMDA at the spinal level.

Good adherence to mediterranean diet can prevent gastrointestinal symptoms: A survey from Southern Italy

AIM

To evaluate how different levels of adherence to a mediterranean diet (MD) correlate with the onset of functional gastrointestinal disorders.

METHODS

As many as 1134 subjects (598 M and 536 F; age range 17-83 years) were prospectively investigated in relation to their dietary habits and the presence of functional gastrointestinal symptoms. Patients with relevant chronic organic disease were excluded from the study. The Mediterranean Diet Quality index for children and adolescents (KIDMED) and the Short Mediterranean Diet Questionnaire were administered. All subjects were grouped into five categories according to their ages: 17-24 years; 25-34; 35-49; 50-64; above 64.

RESULTS

On the basis of the Rome III criteria, our population consisted of 719 (63.4%) individuals who did not meet the criteria for any functional disorder and were classified as controls (CNT), 172 (13.3%) patients meeting criteria for prevalent irritable bowel syndrome (IBS), and 243 (23.3%) meeting criteria for prevalent functional dyspepsia (FD). A significantly lower adherence score in IBS (0.57 ± 0.23, P < 0.001) and FD (0.56 ± 0.24, P < 0.05) was found compared to CNT (0.62 ± 0.21). Females with FD and IBS exhibited significantly lower adherence scores (respectively 0.58 ± 0.24, P < 0.05 and 0.56 ± 0.22, P < 0.05) whereas males were significantly lower only for FD (0.53 ± 0.25, P < 0.05). Age cluster analyses showed a significantly lower score in the 17-24 years and 25-34 year categories for FD (17-24 years: 0.44 ± 0.21, P < 0.001; 25-34 years: 0.48 ± 0.22, P < 0.05) and IBS (17-24 years: 0.45 ± 0.20, P < 0.05; 24-34 years: 0.44 ± 0.21, P < 0.001) compared to CNT (17-24 years: 0.56 ± 0.21; 25-34 years: 0.69 ± 0.20).

CONCLUSION

Low adherence to MD may trigger functional gastrointestinal symptoms, mainly in younger subjects. Moreover, with increasing age, patients tend to adopt dietary regimens closer to MD.

Modern Management of Irritable Bowel Syndrome: More Than Motility

In the treatment of irritable bowel syndrome (IBS), loperamide seems efficacious for diarrhea and ispaghula for constipation, while musculotropic spasmolytics may relieve abdominal pain. Antidepressants were found to be efficacious for abdominal pain, but their tolerance may be problematic and the therapeutic effect varied largely between trials. While meta-analyses suggest efficacy of probiotics as a group, the quality of the trials is often suboptimal and there is large variability. Lubiprostone, a chloride channel activator, and linaclotide, a guanylyl cyclase-C agonist, showed favorable effects on multiple symptoms in IBS with constipation. For IBS with diarrhea (IBS-D), the 5-HT3 receptor antagonist ramosetron showed efficacy in men and women, but is currently only approved in Japan. A multicenter study with the anti-emetic 5-HT3 receptor antagonist ondansetron showed efficacy on stool pattern in IBS-D. The poorly absorbable antibiotic rifaximin and eluxadoline, a mu opioid receptor agonist and delta antagonist, both showed efficacy in phase III trials in IBS-D and were approved by the FDA. Eluxadoline was associated with increased occurrence of sphincter of Oddi spasm and biliary pancreatitis. The non-pharmacological treatment of IBS, with dietary interventions (mainly gluten elimination and low FODMAP (fructose, oligo-, di-, monosaccharides and polyols)) has received a lot of attention lately. While responder rates vary across studies, perhaps based on regional variations in dietary intake of FODMAPs, the dietary approach seems to have acquired recognition as a valid therapeutic alternative. Long-term studies and comparative studies with pharmacotherapy, as well as elucidation of the underlying mechanisms of action, are needed.

What goes around comes around: novel pharmacological targets in the gut-brain axis

The gut and the brain communicate bidirectionally through anatomic and humoral pathways, establishing what is known as the gut-brain axis. Therefore, interventions affecting one system will impact on the other, giving the opportunity to investigate and develop future therapeutic strategies that target both systems. Alterations in the gut-brain axis may arise as a consequence of changes in microbiota composition (dysbiosis), modifications in intestinal barrier function, impairment of enteric nervous system, unbalanced local immune response and exaggerated responses to stress, to mention a few. In this review we analyze and discuss several novel pharmacological targets within the gut-brain axis, with potential applications to improve intestinal and mental health.

Does a low FODMAP diet help IBS?

Irritable bowel syndrome (IBS) is a common condition that can have a significant impact on a person's quality of life. The cause of IBS is unknown but several mechanisms have been proposed including visceral hypersensitivity, central sensitisation, abnormal gut motility and altered gut microbiota. IBS is challenging to manage and many patients report insufficient symptomatic relief from treatment. Approximately 60% of patients identify food as a trigger for their symptoms, and there has been interest in exclusion diets for managing IBS. Dietary adaptation is a common self-management strategy for patients with IBS, with many self-diagnosing intolerance to specific foods. This may lead to patients adopting over-restrictive or inappropriate diets. In recent years, a diet low in poorly absorbed short-chain carbohydrates, known collectively as FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols), has been advocated for the treatment of IBS. Here, we discuss the background to the FODMAP diet and review the evidence supporting its use for people with IBS.

Serotonin and colonic motility

The role of serotonin (5-hydroxytryptamine [5-HT]) in gastrointestinal motility has been studied for over 50 years. Most of the 5-HT in the body resides in the gut wall, where it is located in subsets of mucosal cells (enterochromaffin cells) and neurons (descending interneurons). Many studies suggest that 5-HT is important to normal and dysfunctional gut motility and drugs affecting 5-HT receptors, especially 5-HT3 and 5-HT4 receptors, have been used clinically to treat motility disorders; however, cardiovascular side effects have limited the use of these drugs. Recently studies have questioned the importance and necessity of 5-HT in general and mucosal 5-HT in particular for colonic motility. Recent evidence suggests the importance of 5-HT3 and 5-HT4 receptors for initiation and generation of one of the key colonic motility patterns, the colonic migrating motor complex (CMMC), in rat. The findings suggest that 5-HT3 and 5-HT4 receptors are differentially involved in two different types of rat CMMCs: the long distance contraction (LDC) and the rhythmic propulsive motor complex (RPMC). The understanding of the role of serotonin in colonic motility has been influenced by the specific motility pattern(s) studied, the stimulus used to initiate the motility (spontaneous vs induced), and the route of administration of drugs. All of these considerations contribute to the understanding and the controversy that continues to surround the role of serotonin in the gut.

Stress-induced visceral pain: toward animal models of irritable-bowel syndrome and associated comorbidities

Visceral pain is a global term used to describe pain originating from the internal organs, which is distinct from somatic pain. It is a hallmark of functional gastrointestinal disorders such as irritable-bowel syndrome (IBS). Currently, the treatment strategies targeting visceral pain are unsatisfactory, with development of novel therapeutics hindered by a lack of detailed knowledge of the underlying mechanisms. Stress has long been implicated in the pathophysiology of visceral pain in both preclinical and clinical studies. Here, we discuss the complex etiology of visceral pain reviewing our current understanding in the context of the role of stress, gender, gut microbiota alterations, and immune functioning. Furthermore, we review the role of glutamate, GABA, and epigenetic mechanisms as possible therapeutic strategies for the treatment of visceral pain for which there is an unmet medical need. Moreover, we discuss the most widely described rodent models used to model visceral pain in the preclinical setting. The theory behind, and application of, animal models is key for both the understanding of underlying mechanisms and design of future therapeutic interventions. Taken together, it is apparent that stress-induced visceral pain and its psychiatric comorbidities, as typified by IBS, has a multifaceted etiology. Moreover, treatment strategies still lag far behind when compared to other pain modalities. The development of novel, effective, and specific therapeutics for the treatment of visceral pain has never been more pertinent.

The role of FODMAPs in irritable bowel syndrome

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a condition affecting approximately 10-15% of Western populations. The Rome III criteria are applied to many studies to validate the diagnosis of IBS. The low fermentable oligo, di, monosaccharides and polyol (FODMAP) diet has been the subject of many robust clinical trials and is now used as the primary dietary therapy internationally. This review examines the current evidence for the role of the low FODMAP diet in IBS.

RECENT FINDINGS

Detailed commentary on original research involving FODMAPs and IBS symptoms from 2013 to 2014 is provided.

SUMMARY

The low FODMAP diet has been shown to be an efficacious therapy for reduction of functional gastrointestinal symptoms seen in IBS. Recent publications provide randomized controlled trial and prospective observational evidence in support of the diet for symptom management. The low FODMAP diet appears to be superior to a gluten-free diet in people with self-reported nonceliac gluten sensitivity. Although the low FODMAP diet has not been shown to reduce the prebiotic effect in the colon, total colonic bacterial load was reduced. Further research investigating the potential health implications of both this and the nutritional adequacy of the liberalized low FODMAP diet is required.