Alosetron in irritable bowel syndrome: strategies for its use in a common gastrointestinal disorder

Association of serotonin transporter promoter polymorphism (5-HTTLPR) with orocecal transit time in irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is a multifactorial disorder with altered intestinal motility, secretion, and sensation. Serotonin (5-HT) stimulates gut motility and alters serotonin signaling that may lead to both intestinal and extraintestinal symptoms in IBS.

AIM

The aim of this study was to examine the association of serotonin transporter gene promoter polymorphism (5-HTTLPR) in IBS with orocecal transit time (OCTT) measured by lactulose hydrogen breath test.

METHOD

This prospective case-control study included 151 IBS patients (mean±SD 37.4±11.6 years, median 36, range 19-68). Ninety-two patients were diarrhea-predominant IBS (D-IBS), 44 constipation-predominant IBS (C-IBS), 15 alternating diarrhea and constipation IBS (M-IBS), and 100 healthy controls (mean±SD 37.2±11.4 years, median 36, range 20-64 years). 5-HTTLPR gene polymorphism was studied by polymerase chain reaction-based method. 5-HT levels were measured by enzyme-linked immunosorbent assay (ELISA). Orocecal transit time (OCTT) was measured by a non-invasive lactulose hydrogen breath test. OCTT was also compared with respect to 5-HTTLPR genotypes in different IBS phenotypes.

RESULTS

Serum serotonin levels were significantly higher in overall IBS patients (152±77 ng/mL, p<0.001), D-IBS (184±76 ng/mL, p<0.001), compared to healthy controls (129±56 ng/mL). There was no difference in 5-HT levels between C-IBS (124±53 ng/mL) and controls. In the case of M-IBS, 5-HT levels were (88±49 ng/mL p<0.05) significantly lower than that of controls. OCTT was significantly shorter in D-IBS patients (95±36 min) as compared to controls (112±41 min). In contrast, C-IBS showed significantly prolonged OCTT (136±54 min). There was a significant difference in OCTT between D-IBS and C-IBS patients (p<0.001). There was no significant association found between OCTT and 5-HTTLPR.

CONCLUSIONS

Serum serotonin concentrations were increased in D-IBS compared to controls and C-IBS. OCTT was shorter in D-IBS and delayed in C-IBS patients. There was no association of 5-HTLPR polymorphism with OCTT.

Median arcuate ligament syndrome - Current state of management

Symptomatic celiac artery compression syndrome (CACS) or median arcuate ligament syndrome (MALS) is a controversial diagnosis that should be considered in patients with chronic abdominal pain of unknown etiology despite an extensive medical evaluation. Once suspected, patients should undergo mesenteric duplex ultrasound. Diagnosis is confirmed with elevated celiac artery velocities which normalize with deep inspiration followed by CT angiogram showing the typical "J-hook" conformation of the celiac artery. Patients should then undergo evaluation by a multi-disciplinary team to appropriately select and prepare patients for potential surgical treatment. Surgical options include release of the median arcuate ligament, with or without neurolysis of the celiac nerve plexus, and with or without concomitant revascularization procedures. Approaches can be open, laparoscopic, or robotic. Surgical treatment has an overall success rate of 70-80% with patients reporting improved abdominal pain and quality of life. Post-operatively, patients can have persistent or recurrent abdominal pain and should undergo re-evaluation for possible need for a revascularization procedure for stenosis of the celiac artery or celiac plexus block if the celiac artery flow is normalized. Additionally, some patients will have persistent pain consistent with functional gastrointestinal disorder (FGID) that will then require medical management. Psychiatric comorbidities have been identified as a predisposing factor that may predict poorer outcomes, and there are preliminary findings suggesting that patients with dysautonomia diagnoses may have worse outcomes as well.

Acupuncture combined with Tongxieyaofang for diarrhea-type irritable bowel syndrome: A protocol for meta-analysis

BACKGROUND

As a traditional Chinese medicine external treatment method, acupuncture is characterized by simple operation, significant treatment effect and few side effects. Tong-Xie-Yao-Fang (TXYF), a Chinese patent medicine, combined with acupuncture has been widely used on treating Diarrhea Predominant Irritable Bowel Syndrome (IBS-D). However, the efficacy and safety of TXYF combined with acupuncture for the treatment of IBS-D are unclear. This study aims to investigate verify the efficacy and safety of TXYF combined with acupuncture for IBS-D.

METHODS AND ANALYSIS

Randomized controlled trials of TXYF combined with acupuncture for all IBS-D will be searched in PubMed, the Cochrane Library, Embase, Web of Science, the China National Knowledge Infrastructure, Wanfang Database, Chinese Science and Technology Periodical Database, and Chinese Biomedical Literature Database from inception to October 20, 2020. And Baidu Scholar, Google Scholar, International Clinical Trials Registry Platform, and Chinese Clinical Trials Registry will be searched to obtain more relevant studies comprehensively. The methodological qualities, including the risk of bias, will be evaluated using the Cochrane risk of bias assessment tool, while confidence in the cumulative evidence will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Two researchers will perform data extraction and risk of bias assessment independently. Statistical analysis will be conducted in RevMan 5.3.

RESULTS

Based on the current evidence, the potential rank of the efficacy and safety of TXYF plus acupuncture for IBS-D will be assessed.

CONCLUSION

The findings of the study will provide helpful evidence for the efficacy and safety of TXYF combined with acupuncture in the treatment of IBS-D, facilitating clinical practice and further scientific studies.

Moxibustion treatment for diarrhea-predominant irritable bowel syndrome: study protocol for a randomized controlled trial

BACKGROUND

Irritable bowel syndrome (IBS) is a worldwide disease with high morbidity. The effect of current treatment with Western medicine is not satisfactory. Although moxibustion treatment is widely used for gastrointestinal diseases, randomized controlled trials on the use of this treatment for IBS are limited. This study aims to evaluate the clinical efficacy and safety of moxibustion treatment in patients with diarrhea-predominant irritable bowel syndrome (IBS-D).

METHODS/DESIGN

A multi-center, randomized, single-blind and placebo-controlled trial is employed. 104 cases will be divided into two groups: (1) a mild-warm moxibustion group in which moxa stick is 3-5 cm away from acupuncture points and the skin temperature is maintained at 43 ± 1 °C; and (2) a placebo moxibustion group in which moxa stick is 8-10 cm away from acupuncture points and the skin temperature is maintained at 37 ± 1 °C. Moxibustion is performed on bilateral ST25 and ST36 in the two groups for 30 min each time, three times a week for 6 weeks. The patients are followed up at the 12th and 18th weeks. Adequate relief is used as a primary outcome measure; IBS symptom severity score, Bristol stool form scale, IBS quality-of-life questionnaire, and hospital anxiety and depression scale are used as secondary outcome measures.

DISCUSSION

This study aims to demonstrate the safety and efficacy of moxibustion treatment for IBS-D, which may validate moxibustion as an effective therapy for treating IBS-D.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02421627 (8 April 2015).

Median arcuate ligament syndrome in the pediatric population

OBJECTIVES

Median arcuate ligament syndrome (MALS) is a vascular compression syndrome with symptoms that overlap chronic functional abdominal pain (CFAP). We report our experience treating MALS in a pediatric cohort previously diagnosed with CFAP.

PATIENTS AND METHODS

We prospectively evaluated 46 pediatric (<21years of age) patients diagnosed with MALS at a tertiary care referral center from 2008 to 2012. All patients had previously been diagnosed with CFAP. Patients were evaluated for celiac artery compression by duplex ultrasound and diagnosis was confirmed by computed tomography. Quality of life (QOL) was determined by pre- and postsurgical administration of PedsQL™ questionnaire. The patients underwent laparoscopic release of the median arcuate ligament overlying the celiac artery which included surgical neurolysis. We examined the hemodynamic changes in parameters of the celiac artery and perioperative QOL outcomes to determine correlation.

RESULTS

All patients had studies suggestive of MALS on duplex and computed tomography; 91% (n=42) positive for MALS were females. All patients underwent a technically satisfactory laparoscopic surgical release resulting in a significant improvement in blood flow through the celiac artery. There were no deaths and a total of 9 complications, 8 requiring a secondary procedure; 33 patients were administered QOL surveys. 18 patients completed the survey with 15 (83%) patients reporting overall improvement in the QOL. Overall, 31/46 patients (67%) reported improvement of symptoms since the time of surgery.

CONCLUSIONS

MALS was found to be more common in pediatric females than males. Laparoscopic release of the celiac artery can be performed safely in the pediatric population. Surgical release of the artery and resultant neurolysis resulted in significant improvement in the blood flow, symptoms, and overall QOL in this cohort. The overall improvement in QOL outcome measures after surgery leads us to conclude that MALS might be earlier diagnosed and possibly treated in patients with CFAP. We recommend a multidisciplinary team approach to care for these complex patients.

Functional Dyspepsia Treatment Trial (FDTT): a double-blind, randomized, placebo-controlled trial of antidepressants in functional dyspepsia, evaluating symptoms, psychopathology, pathophysiology and pharmacogenetics

BACKGROUND

Functional dyspepsia (FD) is a common problem affecting up to 10-25% of individuals. FD accounts for significant health care costs and affects quality of life but has no definitive treatment.

OBJECTIVES

The Functional Dyspepsia Treatment Trial (FDTT) aims to test whether treatment with an antidepressant (amitriptyline or escitalopram) leads to improvement of symptoms in patients with moderate to severe FD.

DESIGN

The FDTT is an international multicenter, parallel group, randomized, double-blind, placebo-controlled trial to evaluate whether 12 weeks of treatment with escitalopram or amitriptyline improves FD symptoms compared to treatment with placebo. Secondly, it is hypothesized that acceleration of solid gastric emptying, reduction of postprandial satiation, and enhanced gastric volume change with a meal will be significant positive predictors of short- and long-term outcomes for those on antidepressants vs. placebo. The third aim is to examine whether polymorphisms of GNβ3 and serotonin reuptake transporter influence treatment outcomes in FD patients receiving a tricyclic antidepressant, selective serotonin reuptake inhibitor therapy, or placebo.

METHODS

The FDTT enrollment began in 2006 and is scheduled to randomize 400 patients by the end of 2012 to receive an antidepressant or placebo for 12 weeks, with a 6-month post-treatment follow-up. The study incorporates multiple validated questionnaires, physiological testing, and specific genetic evaluations. The protocol was approved by participating centers' Institutional Review Boards and an independent Data Safety Monitoring Board was established for monitoring to ensure patient safety and a single interim review of the data in December 2010 (ClinicalTrials.gov number NCT00248651).

Thoughts regarding establishment of a system for assessment of the clinical efficacy of Chinese medicine in treating irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder. Chinese medicine has certain advantages in the treatment of IBS though its clinical efficacy has not been widely accepted. The major factor restricting the use of Chinese medicine for treatment of IBS is the lack of a system for assessment of the clinical efficacy of Chinese medicine. In this paper, we present some considerations on how to establish such a system for assessment of the clinical efficacy of Chinese medicine for IBS.

Alosetron for severe diarrhea-predominant irritable bowel syndrome: safety and efficacy in perspective

Irritable bowel syndrome affects 5-10% of North Americans, with an estimated one-third having a diarrhea-predominant form. Alosetron hydrochloride (Lotronex) is a serotonin receptor type 3 antagonist approved in early 2000 for use in women with diarrhea-predominant irritable bowel syndrome (IBS-D). Initial use was widespread, but infrequent serious adverse events of ischemic colitis and severe constipation-related complications prompted alosetron's voluntary withdrawal from the US market in November 2000. Unprecedented public request prompted its reintroduction in 2002 under a Risk Management Plan, including a more restricted indication and a Prescribing Program for Lotronex. Despite these measures, the use of alosetron has been very limited since its reintroduction. Possible deterrents to its use include concerns over safety and the possible medical-legal implications raised by the Risk Management Plan. It is also possible that changes in the natural history and/or diagnosis of IBS-D have reduced the target population. Given the unique regulatory history of alosetron, these issues continue to engender controversy. This article profiles these concerns and reviews the pharmacology, clinical efficacy and safety, and post-marketing experience with alosetron. Myths and misconceptions related to alosetron use, or lack thereof, are addressed to provide the reader with the evidence needed to make informed treatment decisions for their female patients with severe IBS-D.

A randomized, double-blind, placebo-controlled study to assess efficacy and safety of 0.5 mg and 1 mg alosetron in women with severe diarrhea-predominant IBS

OBJECTIVE

Alosetron is indicated for women with chronic, severe diarrhea-predominant IBS (d-IBS) who have not responded adequately to conventional therapy. Constipation is the most common adverse event with alosetron treatment. Multiple dosing regimens were assessed in a randomized, double-blind, placebo-controlled study (S3B30040) to determine efficacy, tolerability, and evaluate constipation rate.

METHODS

705 women with severe d-IBS were randomized to placebo, alosetron 0.5 mg once daily, 1 mg once daily, or 1 mg twice daily for 12 wk. The primary end point was the proportion of week 12 responders (patients with moderate or substantial improvement in IBS symptoms) on the 7-point Likert Global Improvement Scale (GIS). Secondary end points were average rate of adequate relief of IBS pain and discomfort, and bowel symptom improvements.

RESULTS

The proportion of GIS responders at week 12 (primary time point) was significantly greater in all alosetron groups compared with placebo (54/176 [30.7%], 90/177 [50.8%], 84/175 [48%], and 76/177 [42.9%] for placebo, 0.5, 1 mg once daily, and 1 mg twice daily alosetron groups, respectively; P< or = 0.02). Results were similar for the average adequate relief rate (treatment effects > or =12%, P< or = 0.038). Bowel symptoms were improved in all alosetron groups. Constipation was the most common adverse event (9%, 16%, and 19% patients in the 0.5 mg, 1 mg once daily, and 1 mg twice daily groups, respectively). One event of intestinal obstruction and one of ischemic colitis occurred in the 0.5 mg group, and one event of fecal impaction occurred in the 1 mg twice-daily group. All were self-limited and resolved without sequelae.

CONCLUSION

Alosetron 0.5 mg and 1 mg once daily as well as 1 mg twice daily are effective in providing global improvement in IBS symptoms, adequate relief of IBS pain and discomfort, and improvement in bowel symptoms in women with severe d-IBS. Lower dosing regimens resulted in a decreased constipation rate.

Evidence for spinal dorsal horn hyperexcitability in rats following sustained morphine exposure

Repeated or sustained exposure to opioids can not only induce analgesia but also long lasting enhancements in pain sensitivity, a phenomenon reported clinically and in animals. In rats, opioid-induced abnormal pain can be readily measured following continued delivery of morphine and the recruitment of descending facilitatory influences appears essential for the genesis of this state. Here, we provide evidence that an increased excitability develops in neurons of the deep dorsal horn (DH), following 7-10 days of sustained delivery of morphine. Electrophysiological recordings were made in halothane-anesthetised animals implanted with osmotic minipumps containing either morphine (45 microg/0.5 microl/h and 90 microg/0.5 microl/h) or saline. A separate group of naïve animals was also used as controls. Sustained morphine exposure resulted in dose-related and modality-specific enhancements of DH neurons (C-fibre and Adelta-fibre evoked responses, non-potentiated responses) and expanded neuronal receptive fields, as mapped with low intensity mechanical punctate stimuli. Heat and mechanical stimulation of the hindpaw (brush and von Frey filaments) produced similar enhancements in morphine-treated rats compared to control rats, reflecting spinal hyperexcitability. Interestingly, wind-up itself was unaltered. These neuroadaptive changes could form the neuronal basis for the documented clinical and experimental reports of abnormal paradoxical pain after opioids. Since brainstem excitatory controls actively operate during prolonged opioid exposure, the sustained triggering of such influences may act alongside spinal mechanisms such as wind-up to enhance central sensitisation and alter CNS excitability.

Intrarectal Lidocaine Is an Effective Treatment for Abdominal Pain Associated With Diarrhea-Predominant Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is one of the most common disorders seen by gastroenterologists. Visceral hypersensitivity is now well recognized as a clinical marker for the disease. Intrarectal lidocaine has been previously shown to decrease pain report from rectal distension in patients with IBS without any significant serum lidocaine levels. We conducted a prospective, double-blind, crossover trial on 10 patients with IBS to evaluate the effects of 300 mg intrarectal lidocaine jelly on abdominal pain. Ten Caucasian premenopausal women who met the Rome II criteria for diarrhea-predominant IBS were recruited into the study. All of the patients that participated had intermittent left lower quadrant pain and diarrhea. Each patient participated in 2 sessions in which saline jelly (placebo) and lidocaine jelly was administered on a double-blind, crossover basis. Patients participated in these sessions at a time when their ongoing pain was at least 3 on a 0 to 10 visual analogue scale. In comparison to placebo saline jelly, lidocaine jelly significantly decreased abdominal pain (P < .02) for at least 4 hours. None of the patients experienced any side effects. Intrarectal lidocaine may be a potentially useful treatment for chronic abdominal pain in IBS.

PERSPECTIVE

The possible presence of abnormal sodium channels in the rectal and or colonic visceral afferents of patients with IBS might serve as a clue as to the effectiveness of rectal lidocaine. The dose of lidocaine used in this study may be of sufficient strength to normalize aberrant sodium channels that may be present in the colon of patients with IBS without affecting normal sodium channels of either IBS or control subjects.

Enteric P2X receptors as potential targets for drug treatment of the irritable bowel syndrome

The irritable bowel syndrome (IBS) is a gastrointestinal motility disorder affecting millions of patients. IBS symptoms include diarrhea, constipation and pain. The etiology of IBS is due partly to changes in the function of nerves supplying the gastrointestinal tract, immune system activation and to psychological factors. P2X receptors are multimeric ATP-gated cation channels expressed by neuronal and non-neuronal cells. Sensory nerve endings in the gastrointestinal tract express P2X receptors. ATP released from gastrointestinal cells activates P2X receptors on sensory nerve endings to stimulate motor reflexes and to transmit nociceptive signals. Antagonists acting at P2X receptors on sensory nerves could attenuate abdominal pain in IBS patients. Primary afferent neurons intrinsic to the gut, and enteric motor- and interneurons express P2X receptors. These neurons participate in motor reflexes. Agonists acting at enteric P2X receptors may enhance gastrointestinal propulsion and secretion, and these drugs could be useful for treating constipation-predominant IBS. Antagonists acting at enteric P2X receptors would decrease propulsion and secretion and they might be useful for treating diarrhea-predominant IBS. Current knowledge of P2X receptor distribution and function in the gut of laboratory animals provides a rational basis for further exploration of the therapeutic potential for drugs acting at P2X receptors in IBS patients. However, more information about P2X receptor distribution and function in the human gastrointestinal tract is needed. Data on the distribution and function of P2X receptors on gastrointestinal immune cells would also provide insights into the therapeutic potential of P2X receptor agents in IBS.