Emerging treatments for irritable bowel syndrome

Common Urinary and Bowel Disorders in the Geriatric Population

The prevalence of urinary incontinence and other lower urinary tract symptoms increases with older age. These symptoms are more noticeable in men after the seventh decade of life and in women after menopause. Constipation and fecal incontinence are major causes of symptoms in elderly patients and can significantly impair quality of life. This article summarizes the current literature regarding the occurrence and implications of lower urinary tract and bowel symptoms in the geriatric population.

The Incidence of Sexual Dysfunction in Patients With Irritable Bowel Syndrome

Introduction

Several studies have suggested that patients with irritable bowel syndrome (IBS) frequently have symptoms of sexual dysfunction.

Aim

The current study aims to map the current knowledge about the burden of sexual dysfunction in patients with IBS.

Methods

A literature review was conducted on PubMed and EMBASE using the following search terms or combinations thereof: irritable bowel syndrome; functional colonic disease; sexual function; sexual health; sexual behavior; sexual dysfunction; dyspareunia; erectile dysfunction; quality of life; and questionnaire.

Main Outcome Measure

Sexual dysfunction.

Results

1,273 texts were found, 331 duplicates were removed, and 844 texts were excluded because they did not meet the inclusion criteria, leaving 98 full text articles. These were examined and it was found that 41 fulfilled the criteria. 4 questionnaires were found; Irritable Bowel Syndrome Quality of Life (IBS-QOL) questionnaire, the Irritable Bowel Syndrome – Quality of Life (IBSQOL) questionnaire, the Irritable Bowel Syndrome-36 question (IBS-36) questionnaire, and the Arizona Sexual Experience Scale. Subscores for sexual relations in IBS-QOL ranged from 37.7−100 (11.9) for patients with IBS and 82.2−100 (6.6) for controls. The IBSQOL and IBS-36 subscores for sexual relations ranged from 49.7−90.5 (9) to 3.9−5.4 (0.8) with no healthy controls for comparison. After interventions were implemented, there was an improvement in subscores (the IBS-QOL mean changed to 10.5%, IBSQOL mean changed to 3.8%, and the IBS-36 mean changed to 40%). The study using Arizona Sexual Experience Scale showed that 51% of patients with IBS had sexual dysfunction and also scored lower on the IBSQOL questionnaire.

Conclusion

The information about sexual dysfunction in patients with IBS is sparse and emerges primarily from quality of life questionnaires. It seems as though patients with IBS have more sexual problems compared to controls, but further investigation regarding the extent and type of sexual dysfunction is needed.

Sørensen J, Schantz Laursen B, Drewes AM, et al. The Incidence of Sexual Dysfunction in Patients With Irritable Bowel Syndrome. Sex Med 2019;7:371–383.

Review of Rifaximin: Latest Treatment Frontier for Irritable Bowel Syndrome Mechanism of Action and Clinical Profile

Background:

Irritable bowel syndrome is classified as a functional gastrointestinal disorder with the primary symptom of abdominal pain in conjunction with bloating and bowel movement disorder. It affects up to 15% of the world’s population. Among its subtypes, the most common is diarrhoea predominant. However, the current treatment options for diarrhoea-predominant irritable bowel syndrome have had not very promising results; most, such as antispasmodics, only provide partial symptomatic relief. Treatment with antidepressants and alosetron (a 5HT3 antagonist) has shown the most promise to date. The latest drug to be approved for the treatment of irritable bowel syndrome-diarrhoea is rifaximin, which was approved in May 2015. It is a minimally absorbed antibiotic that is used to change the gut microbiota. Small intestinal bacterial overgrowth is one of the causes suggested for irritable bowel syndrome, particularly for the diarrhoea-predominant type. There are various methods for detecting bacterial overgrowth, the simplest of which is breath tests. Rifaximin has been shown to be of benefit to these patients.

Purpose:

The purpose of the study is to discuss the potential mechanism of action of rifaximin, a minimally absorbed antibiotic. In addition, we evaluate the various clinical trials undertaken to study the efficacy and safety profile of rifaximin.

Effects of five candidate laxatives derived from Liriope platyphylla on the 5-HT receptor signaling pathway in three cell types present in the transverse colon

The laxative effects of aqueous extract of Liriope platyphylla (AEtLP) on loperamide (Lop)‑induced constipation have been reported; however, the key compounds and the mechanism underlying these effects remain unclear. Therefore, the laxative effects of five candidates derived from L. platyphylla: Diosgenin (DG), 5-hydroxymethylfurfural (5-HMF), adenosine (AD), hydroxypropyl cellulose (HPC) and uridine (UD) were investigated by examining the alteration of G protein α (Gα) expression, protein kinase C (PKC) phosphorylation and inositol triphosphate (IP3) concentration levels in the 5-hydroxytryptamine (5‑HT; serotonin) receptor signaling pathway. Primary rat intestine smooth muscle cells (pRISMCs), intestinal epithelial cells (IEC)‑18 and B35 cells were cotreated with Lop and the five compounds in order to screen the candidates. AEtLP, prucalopride (PCP) and bisacodyl (BS) served as positive controls. In pRISMCs, Gα expression levels were recovered in the majority of candidate‑treated groups, whereas PKC phosphorylation recovery was observed only in the DG, 5‑HMF and AD treatment groups. In IEC‑18 cells, the AD treatment group mimicked the effects of PCP on PKC phosphorylation levels, whereas the DG, 5‑HMF, HPC and UD treatment groups mimicked the effects of AEtLP and BS. In B35 cells, a greater upregulation of PKC phosphorylation levels were observed in the UD treatment group compared with the PCP and BS treatment groups, whereas DG, 5‑HMF and AD treatment reduced the PKC phosphorylation levels to a greater extent than AEtLP treatment. However, effects similar to AEtLP, PCP and BS on Gα expression levels were not detected in any treatment groups in IEC‑18 and B35 cells. Furthermore, the level of IP3 was enhanced only in pRISMCs, in which all five candidates were effective, while the greatest concentration was observed in the UD treatment group. In conclusion, the results of the present study suggest that UD may be considered the compound with the greatest laxative activity, which may regulate the 5‑HT receptor signaling pathway.

Effects of antidepressants in patients with irritable bowel syndrome and comorbid depression

BACKGROUND

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder that affects up to 15% of community dwelling individuals. Psychiatric comorbidities, particularly symptoms of major depressive disorder (MDD), occur in up to 90% of patients with IBS.

OBJECTIVE

This article reviews the available literature on the use of antidepressants for both IBS and psychiatric depressive symptoms in patients with IBS.

METHODS

MEDLINE and International Pharmaceutical Abstracts (both, 1980-May 2010) were searched for English-language publications that involved antidepressant treatment of MDD in patients with IBS. The search terms were depression, irritable, bowel, treatment, and functional. The reference lists of key articles were searched for additional pertinent articles. Randomized controlled trials published in the past 10 years were given priority.

RESULTS

Of 46 articles identified by the literature search, 11 were included in the review: 4 studies of selective serotonin reuptake inhibitors (SSRIs), 4 of tricyclic antidepressants (TCAs), 1 comparing an SSRI and a TCA, 1 of the serotonin-norepinephrine reuptake inhibitor duloxetine, and a case report involving the tetracyclic antidepressant mirtazapine. Most of the identified studies excluded patients with a diagnosis of depression and/or anxiety. No controlled studies were identified in which the primary outcome was objective assessment of MDD symptoms in patients with IBS. Two of the SSRI studies, one of citalopram and the other of paroxetine, reported approximately 50% improvement in IBS symptoms (both studies, P = 0.01); the study of paroxetine reported a 30% improvement in scores on the Beck Depression Inventory (P = 0.01). The 2 studies of fluoxetine found no statistically significant benefit on IBS symptoms. TCAs were reported to have benefits on IBS symptoms, predominantly diarrhea. Only one of the TCA studies examined and found a significant improvement in depressive symptoms with desipramine 150 mg/d (P = 0.025). Both the open-label study of duloxetine and the case report involving mirtazapine found improvements in IBS and psychiatric symptoms.

CONCLUSIONS

The evidence for the benefit of antidepressant treatment in patients with IBS and comorbid depression was limited and contradictory. Some anti-depressants may help symptoms of IBS, although whether the same drugs and doses are associated with improvements in concomitant depressive symptoms remains to be elucidated.

The D-alanine content of lipoteichoic acid is crucial for Lactobacillus plantarum-mediated protection from visceral pain perception in a rat colorectal distension model

The mechanisms leading to positive effects of probiotics in irritable bowel syndrome and inflammatory bowel disease have not been clarified, but the possible involvement of cell wall components is widely discussed. Reduction of the D-alanine content of lipoteichoic acid (LTA) in Lactobacillus plantarum (Dlt(-) mutant) enhanced its anti-inflammatory properties in a mouse colitis model. Another lactobacillus species inhibited visceral pain perception in response to colorectal distension (CRD) in rats. Therefore, we investigated if LTA modification influences the constitutive intestinal pain perception in addition to modulation of cytokine release. Male Sprague-Dawley rats were gavaged with L. plantarum, L. plantarum Dlt(-) mutant or buffer control, respectively and the responses to CRD were tested in this non-inflammatory model. Tumour necrosis factor (TNF), interferon (IFN)-gamma and interleukin (IL)-10 release were measured in colon tissue homogenates and upon anti-CD3/CD28 activation of isolated splenocytes and mesenteric lymphocytes. Control animals showed significant bradycardia following noxious CRD, whereas only the L. plantarum Dlt(-) mutant inhibited the response. The mutant also decreased the activation-induced release of TNF and IFN-gamma from mesenteric T cells and the IL-10 concentration in colonic tissue, while increasing the activation-induced secretion of IL-10 in splenocytes and mesenteric lymphocytes and the baseline IL-10 release of splenocytes. In conclusion, d-alanine depletion of LTA in L. plantarum inhibited visceral pain perception in healthy, non-inflamed rats. Regardless of the non-inflammatory nature of the model decreased visceral pain perception was seen in parallel with anti-inflammatory properties.

Effect of tegaserod on colonic transit time in male patients with constipation-predominant irritable bowel syndrome

BACKGROUND AND AIMS

Tegaserod is approved for the treatment of constipation-predominant irritable bowel syndrome (C-IBS) in females. The aim of this study was to evaluate the effect of tegaserod on colonic transit time (CTT) and symptoms in male patients with C-IBS.

METHODS

Forty-four males with C-IBS (Rome II) were enrolled. After a baseline washout period of 2 weeks, 40 patients were randomized to 6 mg twice daily of tegaserod or placebo for 12 weeks. Daily bowel habits and weekly satisfactory relief of symptoms were recorded. Total and segmental CTT were measured using radiopaque markers at baseline and after treatment.

RESULTS

The mean +/- SD for the total colonic, right colonic, left colonic and rectosigmoid transit time (in hours) were 18.96 +/- 3.92, 7.74 +/- 1.55, 5.64 +/- 1.51 and 5.58 +/- 2.2 in the tegaserod group compared to 22.47 +/- 3.73, 9.69 +/- 2.33, 6.6 +/- 1.32 and 6.18 +/- 2.22 in the placebo group at the end of 12 weeks. There was a statistically significant difference in the total, right and left CTT in the tegaserod group (P < 0.05) at the end of treatment. Global satisfactory relief at the end of 12 weeks was 75% in the tegaserod group and 50% in the placebo group (P > 0.05). Greater stool frequency occurred in the tegaserod group (P > 0.05). There was a significant decrease in the stool consistency at the end of 12 weeks in patients treated with tegaserod (P < 0.05).

CONCLUSIONS

Tegaserod causes significant acceleration of CTT in male patients with C-IBS. Although there was a trend towards improvement in bowel symptoms in the treated group, this effect was not statistically significant.

Ageing and the gut

The current concepts on diagnosis, clinical features, and management of common gastrointestinal conditions in the elderly population, taking into account physiological aspects of ageing, are evaluated. Gastrointestinal (GI) disorders are discussed with an emphasis on oesophageal problems, Helicobacter pylori infection, malabsorption, diverticular disease, and cancer. GI problems are acquiring greater importance in hospitals and in the community and their incidence is increasing. Newer treatments have less impact on patients' wellbeing and meticulously planned investigation and treatment is needed. Careful selection of patients and application of modern techniques has improved survival and outcomes, with comparable results to those in younger age groups.

The rationale, efficacy and safety evidence for tegaserod in the treatment of irritable bowel syndrome

A growing body of evidence implicates abnormal serotonergic regulation of gastrointestinal function in the pathogenesis of the irritable bowel syndrome (IBS). Drugs targeting this system are therefore attractive concepts. The partial 5-HT4 receptor agonist tegaserod might be predicted to have positive therapeutic effects on a constipated and uncomfortable gut. However, IBS runs a chronic, benign course and carries no associated mortality, so it is imperative that the safety profile of new pharmacological agents made available to physicians is exemplary. The authors review the evidence for 5-HT in the aetiology of IBS and its symptoms, and the data available concerning the partial 5-HT4 receptor agonist tegaserod, in terms of rationale, efficacy and safety.

Review article: The role of serotonergic agents in the treatment of patients with primary chronic constipation

Chronic constipation is a highly prevalent disorder that is associated with significant direct and indirect costs and has substantial impact on patient quality of life. It is more common among women and non-white populations and is evenly distributed across adult age groups. Constipation is a heterogeneous disorder associated with multiple symptoms and aetiologies. Recent research has increased our understanding of the pathogenesis of this disorder and the central role of the neurotransmitter serotonin in mediating gastrointestinal motility, secretion and sensation. Abnormal serotonin signalling and reuptake appear to play central roles in the symptoms of a subset of patients with chronic constipation. This observation provides a rationale for the use of targeted serotonergic agents for the treatment of chronic constipation. As the role of serotonin in gastrointestinal function is further elucidated and additional candidate drugs are developed, it is likely that serotonergic agents will afford additional treatment options for patients with chronic constipation. This article provides a concise review of the evidence supporting a role for serotonin in the pathogenesis of chronic constipation and a summary of the currently available evidence supporting the use of serotonergic agents for this disorder.

Rationale for using serotonergic agents to treat irritable bowel syndrome

PURPOSE

The role of serotonin in gastrointestinal (GI)-tract functioning, the pharmacologic rationale for using serotonergic agents in the treatment of irritable bowel syndrome (IBS), and clinical experience with novel serotonergic agents are described.

SUMMARY

IBS is a common multisymptom disorder that is associated with a high socioeconomic burden. The goal of treatment is to provide rapid and sustained global relief of the multiple symptoms of IBS with a single, effective, well-tolerated agent. Traditional treatment options target single symptoms, and many patients are dissatisfied with the level of relief achieved and adverse effects. Research has revealed that serotonin is involved in three major actions in the gut: (1) mediating intestinal motility, (2) mediating intestinal secretion in the GI tract, and (3) modulating perception in the bowels. Serotonin is also a vital link in the brain-gut axis. Alterations in key elements of serotonin signaling have been demonstrated in patients with IBS. Tegaserod, a selective serotonin type 4 (5-HT(4))-receptor partial agonist, is indicated for use in women with IBS whose primary bowel symptom is constipation. Alosetron, a 5-HT(3)-receptor antagonist, is indicated for use in women with severe diarrhea-predominant IBS in whom traditional therapies have failed. The clinical usefulness of several other serotonergic agents for IBS is being investigated.

CONCLUSION

The use of serotonergic agents in patients with IBS is based on the critical role that serotonin plays in the maintenance of normal gut function and brain-gut communication. Pharmacologic therapies targeting specific serotonin receptors represent an important step in the management of IBS.

Effect of enterokinetic prucalopride on intestinal motility in fast rats

AIM: To evaluate the effects of prucalopride on intestinal prokinetic activity in fast rats and to provide experimental basis for clinical treatment of gastrointestinal motility diseases.

METHODS: Gastrointestinal propulsion rate was measured by the migration rate of activated charcoal, which reflexes gastrointestinal motility function. 120 Spraque-Dawley rats were randomly divided into four groups and received an intravenous injection of physiological saline (served as control), prucalopride 1 mg/kg, prucalopride 2 mg/kg and cisapride 1 mg/kg, respectively. The gastrointestinal propulsion rate was measured 1, 2 or 4 h after intravenous injection of the drugs.

RESULTS: Significant accelerations of gastrointestinal propulsion rate in prucalopride 1 mg/kg and 2 mg/kg groups were found compared with control group at 2 and 4 h (83.2% ± 5.5%, 81.7% ± 8.5% vs 70.5% ± 9.2%, P < 0.01; 91.2% ± 2.2%, 91.3% ± 3.9% vs 86.8% ± 2.6%, P < 0.01). The gastrointestinal propulsion rates at 1, 2 or 4 h were faster in prucalopride 1 mg/kg and 2 mg/kg groups than in cisapride group (84.0% ± 11.7%, 77.1% ± 11.9% vs 66.3% ± 13.6%, P < 0.01, P < 0.05; 83.2% ± 5.5%, 81.7% ± 8.5% vs 75.4% ± 5.9%, P < 0.01, P < 0.05; 91.2% ± 2.2%, 91.3% ± 3.9% vs 88.6% ± 3.5%, P < 0.05, P < 0.05). No difference of gastrointestinal propulsion rate was found between prucalopride 1 mg/kg group and prucalopride 2 mg/kg group (P > 0.05).

CONCLUSION: Prucalopride accelerates intestinal motility in fast rats, and has no dose dependent effect.

Chronic diffuse musculoskeletal pain, fibromyalgia and co-morbid unexplained clinical conditions

This chapter reviews our current knowledge on the presence of overlapping syndromes in one form of chronic diffuse pain, fibromyalgia. Patients with fibromyalgia often present with signs and symptoms of other unexplained clinical conditions, including chronic fatigue syndrome, irritable bowel syndrome, temporomandibular disorders, and multiple chemical sensitivities. The high prevalence, impact on function and opportunities for treatment underscore the need for clinicians and researchers to screen routinely for co-morbid unexplained clinical conditions among persons with fibromyalgia. We, therefore, describe a simple approach to screening for such conditions in accordance with published criteria. Interventions should directly address both fibromyalgia symptoms and co-morbid unexplained clinical conditions, as well as the multiple factors that propagate pain, fatigue and limitations in function.

The enteric nervous system III: a target for pharmacological treatment

The past decade has seen major advances in the pharmacological understanding of the nervous system of the gastrointestinal tract, the enteric nervous system, and its importance for gut functions in several states of disease. Indeed, the enteric nervous system has become a promising target in the treatment of many gastrointestinal symptoms and disorders. Some of these new therapeutic concepts, such as botulinum toxin for achalasia and serotonergic drugs for functional bowel diseases, are already in clinical use. This paper is part 3 of three Minireviews in Pharmacology & Toxicology, and presents the neurogastrointestinal pharmacological therapeutic options in gastrointestinal pain, functional gastrointestinal disorders, inflammatory bowel diseases, cancer and related conditions with focus on future drug targets. The diagnosis of gastrointestinal neuropathy, the role of serotonin and related neuroendocrine transmitters, serotonergic drugs, and neurotrophic factors in neurogastrointestinal pharmacology will be addressed in this context.