A multi-omics study reveals the therapeutic effect of Linderae Radix water extract on irritable bowel syndrome (IBS-D)

ETHNOPHARMACOLOGICAL RELEVANCE

Linderae Radix (Lindera aggregata (Sims) Kosterm) is a traditional Chinese medicine known for its capability to regulate qi and relieve pain, particularly in the context of gastrointestinal disorders.

AIM OF THE STUDY

While our previous research has demonstrated the efficacy of the Linderae Radix water extract (LRWE) in the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D), the precise mechanisms remain elusive. This study aims to provide a comprehensive understanding of the therapeutic effects of LRWE on IBS-D through multi-omics techniques.

MATERIALS AND METHODS

16 S rRNA gene sequencing combined with LC-MS metabolomics was employed to investigate the effect of LRWE on the gut microbiota and metabolites of IBS-D rats. Spearman correlation analysis was performed on the gut microbiota and metabolites.

RESULTS

LRWE administration significantly ameliorated IBS-D rats' symptoms, including diarrhea, visceral hypersensitivity, and low-grade intestinal inflammation. Gut microbiota analysis revealed that LRWE influenced the diversity of the gut microbiota in IBS-D rats by significantly reducing the relative abundance of Patescibacteria and Candidatus Saccharimonas, while increasing the relative abundance of Jeotgalicoccus. Serum metabolomic analysis identified 16 differential metabolites, associated with LRWE's positive effects on IBS-D symptoms, focusing on glyoxylate and dicarboxylic acid metabolism, and cysteine and methionine metabolism. Spearman analysis demonstrated a strong correlation between cecal microbiota composition and serum metabolite levels.

CONCLUSIONS

This study elucidates that LRWE plays a crucial role in the comprehensive therapeutic approach to IBS-D by restoring the relative abundance of gut microbiota and addressing the disturbed metabolism of endogenous biomarkers. The identified bacteria and metabolites present potential therapeutic targets for IBS-D.

Mechanisms of Peitu Yimu acupuncture in repairing intestinal mucosal barrier by regulating CRF/CRFR1 pathway in diarrhea-predominant irritable bowel syndrome rats

OBJECTIVES

To investigate the effect of Peitu Yimu(strengthening spleen and soothing liver) acupuncture on intestinal mucosal barrier function and corticotropin-releasing factor (CRF)/CRF receptor 1 (CRFR1) pathway in rats with diarrhea-predominant irritable bowel syndrome (IBS-D), so as to explore its underlying mechanism in alleviating IBS-D.

METHODS

Forty female SD rats were randomly divided into blank, model, electroacupuncture (EA), and agonist groups, with 10 rats in each group. Except for the blank group, rats in the other groups were given folium sennae infusion by gavage combined with chronic unpredictable mild stress to establish IBS-D model. Rats in the EA group received acupuncture at "Tianshu"(ST25) and EA at "Zusanli"(ST36) and "Taichong"(LR3) (2 Hz/15 Hz) on one side for 20 min, with the side chosen alternately every other day, for 14 days after modeling. Rats in the agonist group received acupuncture 30 min after intravenous injection of CRFR1 agonist urocortin, with the same manipulation method and time as the EA group. Before and after intervention, visceral pain threshold and stool Bristol scores were measured. Elevated plus maze test and open field test were used to detect anxiety and depression like behavior of rats. ELISA was used to detect the contents of CRF and CRFR1 in rats serum. Immunohistochemistry was used to detect the positive expressions of CRF, CRFR1, zonula occludens protein 1(ZO-1), occlusal protein(Occludin), and closure protein 1 (Claudin-1) in colon tissue.

RESULTS

Compared with the blank group, the visceral pain threshold, open arm time percentage (OT%), total distance of movement in the open field test, and positive expression of ZO-1, Occludin, and Claudin-1 in colon were decreased (P<0.01, P<0.05), while Bristol stool scores, serum CRF and CRFR1 contents, and positive expressions of CRF and CRFR1 in colon were increased (P<0.01) in the model group. After intervention and compared with the model group, the visceral pain threshold, OT%, total distance of movement in the open field test, and positive expressions of ZO-1, Occludin, and Claudin-1 in colon were increased (P<0.05, P<0.01), while Bristol stool scores, serum CRF and CRFR1 contents, and positive expressions of CRF and CRFR1 in colon were decreased (P<0.01) in the EA group；the Bristol stool scores, serum CRF content, and CRF positive expression in colon were significantly decreased in the agonist group (P<0.01).

CONCLUSIONS

Peitu Yimu acupuncture can significantly improve visceral hypersensitivity and anxiety-depression state in IBS-D rats. Its mechanism may be related to the inhibition of CRF/CRFR1 pathway and restoration of intestinal tight junction protein expressions.

New paradigm of oral rehydration in patients affected by irritable bowel syndrome with chronic diarrhea

Irritable bowel syndrome with diarrhea is a very frequent clinical condition characterized by disabling intestinal symptoms. This disease presents with daily abdominal pain for at least 3 months related to defecation and associated with a change in the frequency of bowel movements and the shape of the stool. International surveys about this disease report a global prevalence of about 1.5%. A new amino acid based electrolyte solution has recently been commercialized for oral rehydration in diarrhea. It is composed of water, electrolytes, and five selected amino acids that function as sodium co-transporters without containing glucose. In recent years, some studies explored the effectiveness of the amino acid based electrolyte beverage in oncologic patients with gastrointestinal mucositis, reporting good results. Recently, a prospective study to evaluate the clinical impact of the amino acid based medical beverage was conducted in patients with diarrhea predominant irritable bowel syndrome. The research was based on a real-life methodology minimizing the disruption of the routine care. One hundred patients suffering from irritable bowel syndrome with diarrhea drank a solution based on selected amino acids twice a day for 2 wk. Each enrolled patient completed the study and showed a significant response rate with regard to stool consistency and pain reduction. Based on this data, we can hypothesize that the amino acid based oral rehydration solution could be a valid tool in the treatment of patients affected by irritable bowel syndrome with diarrhea. It is certainly necessary to plan high-quality clinical trials comparing glucose based oral solutions and amino acid based solutions in patients with persisting diarrhea. Probably in the near future all oral rehydration solutions will contain amino acids.

Serotonin receptor 2B induces visceral hyperalgesia in rat model and patients with diarrhea-predominant irritable bowel syndrome

BACKGROUND

Serotonin receptor 2B (5-HT2B receptor) plays a critical role in many chronic pain conditions. The possible involvement of the 5-HT2B receptor in the altered gut sensation of irritable bowel syndrome with diarrhea (IBS-D) was investigated in the present study.

AIM

To investigate the possible involvement of 5-HT2B receptor in the altered gut sensation in rat model and patients with IBS-D.

METHODS

Rectosigmoid biopsies were collected from 18 patients with IBS-D and 10 patients with irritable bowel syndrome with constipation who fulfilled the Rome IV criteria and 15 healthy controls. The expression level of the 5-HT2B receptor in colon tissue was measured using an enzyme-linked immunosorbent assay and correlated with abdominal pain scores. The IBS-D rat model was induced by intracolonic instillation of acetic acid and wrap restraint. Alterations in visceral sensitivity and 5-HT2B receptor and transient receptor potential vanilloid type 1 (TRPV1) expression were examined following 5-HT2B receptor antagonist administration. Changes in visceral sensitivity after administration of the TRPV1 antagonist were recorded.

RESULTS

Here, we observed greater expression of the 5-HT2B receptor in the colonic mucosa of patients with IBS-D than in that of controls, which was correlated with abdominal pain scores. Intracolonic instillation of acetic acid and wrap restraint induced obvious chronic visceral hypersensitivity and increased fecal weight and fecal water content. Exogenous 5-HT2B receptor agonist administration increased visceral hypersensitivity, which was alleviated by successive administration of a TRPV1 antagonist. IBS-D rats receiving the 5-HT2B receptor antagonist exhibited inhibited visceral hyperalgesia.Moreover, the percentage of 5-HT2B receptor-immunoreactive (IR) cells surrounded by TRPV1-positive cells (5-HT2B receptor I+) and total 5-HT2B receptor IR cells (5-HT2B receptor IT) in IBS-D rats was significantly reduced by the administration of a 5-HT2B receptor antagonist.

CONCLUSION

Our finding that increased expression of the 5-HT2B receptor contributes to visceral hyperalgesia by inducing TRPV1 expression in IBS-D patients provides important insights into the potential mechanisms underlying IBS-D-associated visceral hyperalgesia.

Effectiveness of an amino acid beverage formulation in diarrhea-predominant irritable bowel syndrome: A pragmatic real-world study

BACKGROUND

Amino-acid based medical foods have shown promise in alleviating symptoms of drug induced gastrointestinal side effects; particularly, diarrhea-predominant symptoms. Irritable bowel syndrome (IBS) is a gastrointestinal disorder that affects up to 9% of people globally, with diarrhea predominant IBS (IBS-D) being the most prevalent subtype. Further trials are needed to explore potential added benefits when integrated into standard care for IBS-D.

AIM

To assess the effectiveness of an amino acid-based medical food as an adjunct to standard of care for adults with IBS-D.

METHODS

This is a pragmatic, real world, open label, single arm study comparing a 2-week baseline assessment to a 2-week intervention period. One hundred adults, aged 18 to 65 years, with IBS-D, according to Rome IV criteria, were enrolled after completing a 2-week baseline assessment period and received a 2-week supply of an amino acid based medical food which was consumed at home twice daily on top of their standard of care. The primary outcome was an assessment of tolerability after 2-weeks of consumption, while secondary outcomes included changes in stool consistency (Bristol Stool Form Scale), severity of abdominal pain & discomfort, symptoms of urgency, Global Improvement Survey (GIS), and the IBS severity scoring system (IBS-SSS).

RESULTS

The test product was well-tolerated as each participant successfully completed the full 14-day trial, and there were no instances of dropouts or discontinuation of the study product reported. Forty percent of participants achieved a 50% or more reduction in the number of days with type 6-7 bowel movements (IBS-D stool consistency responders). Fifty-three percent of participants achieved a clinically meaningful reduction of 30% in mean weekly pain scores, and 55% experienced the same for mean weekly discomfort scores (IBS-D pain and discomfort responders). Participants experienced a mean -109.4 (95% confidence interval: -130.1, -88.8) point reduction on the IBS-SSS and 52% experienced a minimally clinically important difference of > 95 points. An IBS-SSS category shift from severe to moderate or mild occurred in 69% of participants. For functional symptoms, 76% of participants reported symptom relief on the GIS.

CONCLUSION

The amino acid-based medical food was well-tolerated, when added to the standard of care, and demonstrated improvements in both overall IBS symptom severity and IBS-D symptoms within just 2 wk.

Different therapies of Chinese herbal medicine for diarrhea-predominant irritable bowel syndrome: A network meta-analysis of double-blinded, placebo-controlled trials

ETHNOPHARMACOLOGICAL RELEVANCE

Shuganjianpi Therapy (SGJP), Jianpi Therapy (JP), Shugan Therapy (SG), Jianpiwenshen Therapy (JPWS), and Shuganjianpiwenshen Therapy (SGJPWS), consisting of formulas from Chinese herbal medicine (CHM), have been tremendously applied to irritable bowel syndrome (IBS). However, it remains uncertain when exploring the preferable option among different CHM therapies for diarrhea-predominant irritable bowel syndrome (IBS-D).

AIM OF THE STUDY

To compare and rank the efficacy and safety of different CHM therapies for IBS-D.

MATERIALS AND METHODS

We searched randomized, double-blinded, placebo-controlled trials through mainstream databases from their inception to October 31, 2022. Eligible randomized controlled trials (RCTs) applied one of the CHM therapies as the experimental group and placebo as the control group. Two authors independently extracted data into a form and evaluated the quality of the retrieved articles by the Cochrane Risk of Bias Tool. At least one of the following outcomes was assessed: Serotonin, Neuropeptide Y (NPY), Incidence of Adverse Events (AE), and Irritable Bowel Syndrome-Severity Scoring System (IBS-SSS) with its subscales of Severity of Abdominal Pain (SAP), Frequency of Abdominal Pain (FAP), Severity of Abdominal Distension (SAD), Dissatisfaction with Bowel Habits (DBH), and Interference with Quality of Life (IQOL). A Bayesian network meta-analysis on a random-effect model was conducted using R 4.2.2 software.

RESULTS

1367 records were retrieved from databases in an initial search. Fourteen studies involving six interventions with 2248 participants were identified. Provided pairwise comparisons, the surface under the cumulative ranking curve (SUCRA) ranking, and cluster analysis, JPWS was the best option for ameliorating clinical symptoms simultaneously, which included IBS-SSS, SAP, FAP, SAD, DBH, and IQOL. As for AE, JPWS contributed to fewer adverse events than others as well. In respect of serum indicators, we noticed the dominance of SGJP in regulating both serotonin and NPY.

CONCLUSIONS

JPWS and SGJP were the most prominent CHM therapies for IBS-D in terms of clinical symptoms, including abdominal pain, distension, bowel habits, and improvement of quality of life. The effect of JP and SG for IBS-D required further investigation. As a potential candidate, SGJP may well treat IBS-D by mediating dysmotility, visceral hypersensitivity, and the gut-brain axis with an increase of NPY and a reduction of serotonin. For safety, JPWS was ideal for the fewest adverse events in the treatment of IBS-D. On account of a small sample size and possible geographical publication bias, more double-blinded and placebo-controlled trials with larger samples worldwide would be necessary for strengthening current evidence.

Effect of acupuncture on the expression of neuropeptides and related inflammatory factors in rats with diarrhea-predominant irritable bowel syndrome

OBJECTIVES

To observe the effect of acupuncture on the expressions of neuropeptides and related inflammatory factors in rats with diarrhea-predominant irritable bowel syndrome(IBS-D), so as to explore the mechanism of acupuncture in the treatment of IBS-D.

METHODS

Male Wistar rats were randomly divided into blank group, model group, medication group, and acupuncture group, with 6 rats in each group. Except for the blank group, the other groups were subjected to 14-day "acetic acid enema + restraint stress" to establish the IBS-D rat model. After successful modeling, the medication group received gavage of pinaverium bromide(15 mg/kg) once a day, and the acupuncture group received acupuncture at "Baihui"(GV20) and bilateral "Tianshu"(ST25), "Shangjuxu"(ST37), "Zusanli"(ST36), and "Taichong"(LR3) for 20 min every day, both groups were treated continuously for 14 days. The general state of the rats in each group was observed, and the body weight of the rats was measured. The open-field experiment was conducted to measure the horizontal and vertical movements, and the number of fecal pellets of rats. The histopathological morphology of hypothalamus and colon of rats was observed by HE staining. Toluidine blue staining was used to observe and count the mast cells(MCs) in the colon tissue of rats. ELISA was used to detect the serum contents of tumor necrosis factor-α(TNF-α) and interleukin(IL)-10. Real-time fluorescence quantitative PCR was performed to detect the mRNA expressions of calcitonin gene-related peptide(CGRP) in the hypothalamus and colon tissue. Western blot was used to detect the expressions of corticotropin-releasing factor(CRF) in the hypothalamus and colon tissue.

RESULTS

HE staining showed that there was inflammatory cell infiltration in the lamina propria of colon in the model group, and it was reduced in the other groups. Compared with the blank group, the model group showed significantly decreased body weight, decreased walking distance and upright times in open field experiment, decreased serum IL-10 contents(P<0.05, P<0.01), increased fecal pellet number (P<0.01), increased MC number in the colon tissue, serum TNF-α contents, and CGRP mRNA expressions and CRF expressions in the hypothalamus and colon tissue(P<0.01). Compared with the model group, both medication and acupuncture groups showed significantly increased body weight, walking distance and upright times in the open-field experiment, and serum IL-10 contents(P<0.01, P<0.05), significantly decreased fecal pellet number (P<0.05), significantly decreased MC number in the colon tissue, serum TNF-α contents, and CGRP mRNA expressions in the hypothalamus and colon tissue(P<0.01)；at the same time, the acupuncture group showed significantly decreased CRF expressions in the hypothalamus and colon tissue(P<0.01, P<0.05). There was no significant difference in the above indicators between the medication group and the acupuncture group.

CONCLUSIONS

Acupuncture can improve the general and emotional state, inflammatory response, and neuropeptide expression in rats with IBS-D, and alleviate the symptoms of IBS-D, which may be related to the regulation of neuropeptides and inflammatory factors levels.

Comparison of the effects of moxibustion and acupuncture of combined "Biao-Ben" acupoints on intestinal sensitivity and autonomic nervous system function in rats with diarrhea-predominant irritable bowel syndrome

OBJECTIVES

To compare the effects of moxibustion and acupuncture of combined "Biao-Ben" acupoints (Biao indicates pathogenic factors of disease, Ben refers to body constitution) on a rat model of irritable bowel syndrome with diarrhea (IBS-D).

METHODS

Forty female SD rats were randomly divided into 4 groups：normal group, model group, moxibustion group, and acupuncture group, with 10 rats in each group. The IBS-D rat model was established by administering acute-chronic stress combined with folium sennae gavage for 28 days. Rats in the moxibustion group received moxibustion at bilateral "Zusanli"(ST36), "Guanyuan"(CV4), and "Neiguan"(PC6), while those in the acupuncture group received acupuncture at the same acupoints, both for 15 min every time, once a day. The treatments were administered for 21 days. The loose stool rate was observed. Colonic pain threshold and colonic distension threshold were measured by a self-made balloon catheter. Total distance traveled and grid crossing numbers were observed by open field test. Heart rate variability(HRV) time domain indexes SDANN and PNN50 were acguired by using electrophysiological recorder. Histopathological changes in the colon tissue were observed after HE staining. Contents of interleukin-6(IL-6), IL-8, and tumor necrosis factor-alpha(TNF-α) in serum were detected by ELISA.

RESULTS

Compared with the normal group, rats in the model group showed increased loose stool rate(P<0.05), decreased pain threshold and distension threshold(P<0.05), reduced total distance traveled and grid crossing numbers in the open field test(P<0.05), decreased HRV time domain indexes SDANN and PNN50(P<0.01, P<0.05), and elevated levels of serum IL-6, IL-8, and TNF-α contents(P<0.05). Compared with the model group, the moxibustion group and acupuncture group showed decreased loose stool rate(P<0.05), increased total distance traveled and grid crossing numbers in the open field test(P<0.05), increased pain threshold and distension threshold(P<0.05), increased SDANN and PNN50 (P<0.05), and decreased levels of serum IL-6, IL-8, and TNF-α contents(P<0.05). Compared with the acupuncture group, the moxibustion group showed further decreased loose stool rate(P<0.05), increased total distance traveled and grid crossing numbers in the open field test(P<0.05), increased pain threshold and distension threshold(P<0.05), increased SDANN and PNN50(P<0.05), and decreased levels of serum IL-6, IL-8, and TNF-α contents(P<0.05). No significant pathological changes were observed in the colon tissue of rats in each group.

CONCLUSIONS

Moxibustion of combined "Biao-Ben" acupoints is more effective in regulating HRV and serum IL-6, IL-8, and TNF-α contents in the IBS-D rat model. Based on the combined "Biao-Ben" acupoints method, moxibustion has better therapeutic effects on IBS-D than acupuncture.

Efficacy and dose response of Lactiplantibacillus plantarum in diarrhea-predominant irritable bowel syndrome

BACKGROUND

Probiotics have shown promise in alleviating symptoms of diarrhea-predominant irritable bowel syndrome (IBS-D); however, the certainty of evidence is low. Well-powered randomized controlled dose-ranging trials are warranted on promising single-strain candidates.

AIM

To investigate the clinical efficacy of Lactiplantibacillus plantarum (L. plantarum) Lpla33 (DSM34428) in adults with IBS-D.

METHODS

This is a randomized, double-blind, placebo-controlled, multi-center, and dose-ranging study. Three hundred and seven adults, 18-70 years of age, with IBS-D, according to Rome IV criteria, were allocated (1:1:1) to receive placebo or L. plantarum Lpla33 at 1 × 109 (1B) or 1 × 1010 (10B) colony-forming units/d over an 8-wk intervention period. The primary outcome was the change in IBS severity scoring system (IBS-SSS) total score after 8 wk, while secondary and exploratory outcomes included abdominal pain severity, IBS related quality of life, stool and microbial profile, and perceived stress.

RESULTS

IBS-SSS was significantly reduced, after 8 wk, in participants receiving L. plantarum 1B (-128.45 ± 83.30; P < 0.001) and L. plantarum 10B (-156.77 ± 99.06; P < 0.001), compared to placebo (-58.82 ± 74.75). Further, a dose-ranging effect was observed, with a greater absolute reduction in the L. plantarum 10B group (P < 0.05). A reduction in sub-scores related to abdominal pain, abdominal distension, bowel habits, and quality of life was observed in both L. plantarum groups compared to placebo (P < 0.001). Further, 62.5% and 88.4% of participants administered L. plantarum 1B and 10B, respectively, were classified as stool consistency responders based on a reduction in diarrheal stool form, as compared to 26.3% in the placebo group (P < 0.001). In contrast, no significant shifts were observed in microbial diversity.

CONCLUSION

L. plantarum Lpla33 (DSM34428) is well tolerated and improves IBS symptom severity with a dose-ranging effect and a corresponding normalization of bowel habits in adults with IBS-D.

Altered gut microbiota-host bile acid metabolism in IBS-D patients with liver depression and spleen deficiency pattern

BACKGROUND

Dysregulation of gut microbiota-host bile acid (BA) co-metabolism is a critical pathogenic factor of diarrhea-predominant irritable bowel syndrome (IBS-D). Traditional Chinese Medicine (TCM), instructed by pattern differentiation, is effective in treating IBS-D, in which liver depression and spleen deficiency (LDSD) is the most prevalent pattern. Still, it is unclear the linkage between the LDSD pattern and the BA metabolic phenotype.

PURPOSE

This study aimed to uncover the biological basis of the LDSD pattern from the BA metabolic perspective.

METHODS

Patients with IBS-D completed questionnaires regarding the irritable bowel severity scoring system (IBS-SSS), stool frequency, Stool Bristol scale, and Self-Rating Scales of mental health. Fasting blood and morning feces were collected to analyze the gut metagenome and BA-related indices/metabolites.

RESULTS

IBS-D patients with LDSD had a higher incidence of BA overexcretion (41% vs. 23% non-LDSD) with significant elevations in fecal total BAs and serum BA precursor 7α-hydroxy-4-cholesten-3-one levels. Compared to controls or non-LDSD patients, LDSD patients had a featured fecal BA profile, with higher proportions of deoxycholic acid (DCA), 7-ketodeoxycholic acid, and lithocholic acid. It is consistent with the BA-metabolizing genomic changes in the LDSD gut microbiota characterized by overabundances of 7-dehydroxylating bacteria and BA-inducible genes (baiCD/E/H). The score of bowel symptoms (stool frequency and abdominal pain) showing greater severity in the LDSD pattern were positively correlated with bai-expressing bacterial abundances and fecal DCA levels separately.

CONCLUSION

We clarified a differed BA metabolic phenotype in IBS patients with LDSD, which closely correlates with the severity of bowel symptoms. It demonstrates that gut microbiota and host co-metabolism of BAs would provide crucial insight into the biology of the LDSD pattern and its internal relationship with IBS progression.

[Study on the mechanism of electroacupuncture repairing intestinal barrier via regulating mast cell in rats with diarrhea-predominant irritable bowel syndrome]

OBJECTIVE

To observe the effect of electroacupuncture (EA) on mast cell activation-related substances and intestinal barrier function in diarrhea-predominant irritable bowel syndrome (IBS-D) model rats, so as to explore its underlying mechanisms.

METHODS

Thirty female SD rats were randomly divided into control group, model group and EA group, with 10 rats in each group. IBS-D model was established by chronic unpredictable mild stress combined with senna solution gavage. Rats in the EA group received EA treatment (2 Hz/15 Hz，0.1-1.0 mA) at "Zusanli" (ST36), "Taichong"(LR3) and "Tianshu"(ST25), 20 min per day, for a total of 14 days, with sides alternated daily. Visceral pain threshold was used to evaluate visceral hypersensitivity, diarrhea index was used to evaluate diarrhea degree. After all treatments, the pathological scores of colon were recorded after HE staining, the contents of cholecystokinin (CCK), substance P (SP), tryptase (TPS) and adenosine triphosphate (ATP) in colon were detected by ELISA, and the expressions of colonic tight junction protein ZO-1 and occludin were detected by Western blot.

RESULTS

Compared with the control group, the visceral pain threshold, the expression levels of colonic ZO-1 and occludin proteins decreased (P<0.01), while the diarrhea index, the contents of colonic CCK, SP, TPS and ATP were significantly increased (P<0.01) in the model group. After intervention, in comparison with the model group, the visceral pain thre-shold, the protein expression levels of colonic ZO-1 and occludin protein increased (P<0.01), while the diarrhea index, the contents of colonic CCK, SP, TPS and ATP were significantly decreased (P<0.01) in the EA group.

CONCLUSION

EA can significantly alleviate the symptoms of visceral hypersensitivity and diarrhea in IBS-D rats. Its mechanism may be related to down-regulating colonic CCK, SP, TPS and ATP, inhibiting mast cell activation and degranulation, and up-regulating colonic barrier tight junction proteins.

Effect of acupuncture for diarrhea-predominant irritable bowel syndrome: study protocol for a randomized clinical trial

Background

Diarrhea-predominant irritable bowel syndrome (IBS-D) is the most common subtype of IBS. Acupuncture is commonly used to treat IBS-D, but its effect is uncertain because of the poor quality of prior studies. This trial aims to evaluate the efficacy and safety of acupuncture treatment for IBS-D through comparisons with sham acupuncture.

Methods/design

This is a large-scale, multi-center, randomized, two-arm interventional clinical trial. Participants will take part in a total of 20 weeks of study, which contained 3 phases: 2-week screening, 6-week treatment, and 12-week follow-up. Based on the composite response rate of the primary endpoint in our pilot study (a sham acupuncture response rate of 27% and a true acupuncture of approximately 45%), 280 randomly allocated participants were planned. Eligible participants will be randomly assigned to the true acupuncture group and sham acupuncture group according to a ratio of 1:1, and a total of 15 sessions of treatment overall 6-week treatment period will be brought. The primary endpoint is a composite response rate at week 6, and the responder is defined as who responses in both abdominal pain intensity and stool consistency. Furthermore, composite response rates at other weeks, IBS Symptom Severity Scale, IBS Quality of Life, Adequate Relief scale, and individual IBS symptoms (abdominal pain, bloating, stool frequency) are chosen as secondary endpoints.

Discussion

This trial may provide high-quality evidence for the efficacy and safety of acupuncture in the treatment of IBS-D. The results of this study will be published in peer-reviewed journals.

Trial registration

Chinese Clinical Trial Registry: ChiCTR2100044762. Registered on 26 March 2021.

The Chinese herbal formula Huoxiang Zhengqi for diarrhea-predominant irritable bowel syndrome (CHAIRS): a study protocol for a double-blinded randomized controlled trial

Background

Diarrhea-predominant irritable bowel syndrome (IBS-D) is a common chronic digestive disease. Recent observational studies have reported that the Chinese herbal formula Huoxiang Zhengqi (HXZQ) can relieve IBS-D symptoms, but no high-level evidence is presented. Therefore, we want to evaluate the efficacy and safety of HXZQ for IBS-D patients.

Methods

This is a double-blind, randomized, placebo-controlled trial. The 212 eligible patients with IBS-D will be randomly assigned to receive either HXZQ oral liquid or a placebo, at a 1:1 ratio, for 4 weeks with a 4-week follow-up period. Adequate relief will be the primary outcome measures. IBS symptom severity score, IBS quality-of-life questionnaire, EQ-5D-5L, and Chinese medicine symptom questionnaire will be the secondary outcome measures.

Discussion

This trial aims to demonstrate the efficacy and safety of HXZQ for IBS-D, which is expected to be an effective IBS-D treatment.

Trial registration

The trial was registered with the Chinese Clinical Trial Registry, ChiCTR1900026837. Registered on 24 October 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05444-w.

[Mind-regulating and spleen-strengthening needling technique improves abdominal hypersensitivity and emotion by enhancing functional connectivity between hippocampus and brain regions in diarrhea-predominant irritable bowel syndrome patients]

OBJECTIVE

To compare the difference of brain functional connectivity between diarrhea-predominant irritable bowel syndrome (IBS-D) patients and healthy volunteers and changes after acupuncture intervention, so as to investigate the underlying mechanism of acupuncture in regulating functional activities of IBS-D patients by using seed point correlation analysis.

METHODS

A total of 25 IBS-D patients and 25 healthy volunteers were recruited in the present study and respectively attributed to acupuncture group and control group. The IBS-D patients received manual acupuncture stimulation of Baihui (GV20), Yintang (EX-HN3), and bilateral Tianshu (ST25), Zusanli (ST36), Shangjuxu (ST37), Sanyinjiao (SP6) and Taichong (LR3) with mind-regulating and spleen-strengthening technique for 30 min, once a day, 3 days a week for 6 weeks. Before and after the intervention, the IBS symptom severity scale (IBS-SSS) was used to assess the patients' state of abdominal pain, distention and defecation, and Hamilton Anxiety Rating Scale (HAMA) employed to evaluate the patients' anxiety severity. The resting state functional magnetic resonance imaging (rs-fMRI) data were acquired and preprocessed by using SPM8 and DPARSE soft-wares. Seeds (bilate-ral hippocampus regions) to whole-brain analysis was performed to obtain the mean time series of the left and right seed regions, followed by making Pearson correlation analysis to obtain the correlation coefficient (time series from each seed region with the rest of the voxels in the brain), and making a multivariate comparative correction to get data of functional connectivity (FC) of bilateral hippocampus regions and to find the related difference in the brain regions. Then, the differences of the FC of brain regions between IBS-D patients and healthy volunteers were compared.

RESULTS

Following acupuncture treatment, both the HAMA and IBS-SSS scores were significantly reduced in the acupuncture group compared with its pre-treatment (P<0.01). Compared with the healthy volunteers, there were a reduction in the functional connectivity between the left hippocampus seed region and the right inferior temporal gyrus, left fusiform gyrus and left superior gyrus, and between the right hippocampus region and the right fusiform gyrus, left inferior temporal gyrus, left inferior occipital gyrus, left rectus gyrus, left insula, left precuneus, right angular gyrus, left middle occipital gyrus, right precuneus, and the left superior temporal gyrus, and an increase in the FC between the left hippocampus and left superior temporal gyrus was increased in ISB-D patients. Self-comparison showed that after the treatment, the FC was increased between the left hippocampus seed region and the right inferior temporal gyrus, left fusiform gyrus, bilateral lingual gyrus, left amygdala, right inferior occipital gyrus, right insula, right middle frontal gyrus, left middle frontal gyrus and the left middle occipital gyrus; and between the right hippocampus seed region and the posterior inferior cerebellar lobe, left inferior temporal gyrus, left suboccipital gyrus, right fusiform gyrus, left insula, right inferior frontal gyrus, left superior temporal gyrus, left middle occipital gyrus, right middle frontal gyrus, left supplementary motor area and right supplementary motor area, and decreased between the left hippocampus region and the left anterior cingulate, paracingulate gyrus and the right posterior central gyrus in IBS-D patients.

CONCLUSION

Mind-regulating and spleen-strengthening acupuncture intervention may improve the abdominal pain and distension and emotional state in IBS-D patients, which is possibly associated with its effect in enhancing FC between the hippocampus and brain regions.

[Involvement of Pirt /TRPV1 signaling in acupuncture-induced reduction of visceral hypersensitivity in diarrhea-predominant irritable bowel syndrome rats]

OBJECTIVE

To observe the effect of electroacupuncture (EA) on the expression of Pirt (a regulator of TRPV1) in the dorsal root ganglia (DRG) and transient receptor potential vanilloid 1 (TRPV1, a molecular sensor of noxious heat and capsaicin) in the colonic mucosa in rats suffering from diarrhea-predominant irritable bowel syndrome (IBS-D), so as to explore its mechanisms underlying alleviation of visceral hypersensitivity of IBS-D.

METHODS

Forty SD rats (half male and half female) were randomly assigned to control, model, EA, and medication groups by lottery, with 10 rats in each group. The IBS-D model was established by chronic unpredictable mild stress (CUMS) and gavage of senna soaking fluid. Rats in the EA group received EA (2 Hz/15 Hz,0.1-1 mA) stimulation of unilateral "Tianshu"(ST25), "Zusanli" (ST36), "Sanyinjiao"(SP6) and "Taichong"(LR3) for 15 min once a day for 14 days, and rats of the medication group received intragastric administration of pinave-rium bromide (10 mL/kg, 2.7 mg/mL) once daily for 14 days. The visceral pain threshold (VPT) was measured by using abdominal wall withdrawal reflex (AWR) test. The diarrhea index （loose stool rate ［total number of loose stool/total number of defecation］ X mean loose degree ［0-4 grades according to the filter paper stain diameter］ in 6 h/d） was used to assess the severity of diarrhea. The expression of Pirt in the DRG and TRPV1 in the colonic mucosa tissue was detected using immunohistochemistry.

RESULTS

After modeling, the VPT was obviously reduced (P<0.01), while the diarrhea index, mean optical density of Pirt and TRPV1 were remarkably increased in the model group relevant to the control group (P<0.01). After the interventions, the VPT was obviously increased while the diarrhea index, and the mean optical density of Pirt and TRPV1 was noticeably decreased in both EA and the medicine groups in contrast to the model group (P<0.01). No significant differences were found between the EA and medicine groups in up-regulating VPT and down-regulating the diarrhea index, and Pirt and TRPV1 expression (P>0.05).

CONCLUSION

EA can effectively alleviate visceral hypersensitivity in IBS-D rats, which may be related to its effect in down-regulating the expression level of DRG Pirt and colonic TRPV1.

Gut microbiota composition and functional prediction in diarrhea-predominant irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is common and difficult to treat and its pathogenesis is closely related to gut microbiota. However, differences in gut microbiota of patients in different regions make it more difficult to elucidate the mechanism of IBS. We performed an analysis of gut microbiota composition and functional prediction in Chinese patients with diarrhea-predominant IBS (IBS-D).

METHODS

Fecal samples were obtained from 30 IBS-D patients and 30 healthy controls (HCs) in Nanchang, China. Using 16S gene sequence profiles, we analyzed the abundance of dominant microbiota at different taxonomy levels. Based on 16S information, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was used to predicting the function of gut microbiota.

RESULTS

Compared to HCs, gut microbiota richness but not diversity was decreased in IBS-D patients. The abundant phyla Firmicutes, Fusobacteria and Actinobacteria decreased significantly, and Proteobacteria increased significantly in IBS-D patients. PICRUSt indicated that function expression of gut microbiota in IBS-D patients was up-regulated in metabolism of cofactors and vitamins, xenobiotics biodegradation and metabolism, and down-regulated in environmental adaptation, cell growth and death.

CONCLUSIONS

Compared with the normal population in China, IBS-D patients are characterized by complex and unstable gut microbiota, which may influence inflammation and metabolism of the host.

Diarrhea-Predominant Irritable Bowel Syndrome: Medical Management Update

Irritable bowel syndrome (IBS) is a prevalent gastrointestinal disorder, which impacts the quality of life, work productivity and social activities of patients. Diarrhea-predominant IBS (IBS-D) is one of several subtypes, and accounts for approximately one third of all cases. Currently available treatments are typically unable to alleviate the cardinal symptoms of IBS-D, including abdominal pain and diarrhea, and a clinical unmet need remains for an effective treatment which simultaneously relieves multiple symptoms. Patients may benefit from a multipronged, individualized approach, including dietary modifications, and psychological and pharmacological therapies. The aim of this review is to provide an update on the available and upcoming treatment options for IBS-D in Canada, with reference to the recently updated Canadian IBS consensus guidelines. Initial treatment approaches include lifestyle modifications, dietary modifications, and non-prescription therapies such as peppermint oil. While some medications such as tricyclic antidepressants are also used to treat IBS-D symptoms, eluxadoline and rifaximin are the only two pharmacological therapies approved for the treatment of IBS-D in Canada. Key clinical trial data for the currently available pharmacological options are presented to provide an overview of the efficacy and safety of these agents.

Efficacy of Tong-Xie-Yao-Fang granule and its impact on whole transcriptome profiling in diarrhea-predominant irritable bowel syndrome patients: study protocol for a randomized controlled trial

BACKGROUND

Irritable bowel syndrome (IBS) is one kind of common functional bowel disease with obscure pathogenesis, and exploration about whole transcriptome profiling in IBS-D is still negligible. Conventional medications have limited effects, which makes focus shifted to traditional Chinese medicine (TCM). Tong-Xie-Yao-Fang, as a classic herbal formula in TCM, is pretty effective and safe for the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D), but the underlying therapeutic mechanism remains unknown. We aim to verify the efficacy and safety of TXYF granule (the formula particles mixed together) in IBS-D and elucidate the gene-level mechanism of IBS-D and therapeutic targets of TXYF granule based on whole transcriptome analysis.

METHODS/DESIGN

This is a randomized, double-blind, and placebo-controlled clinical trial consisting of 2 weeks of run-in period, 12 weeks of treatment period, and 8 weeks of follow-up period. We will enroll 120 participants with IBS-D, who will be randomly assigned to the TXYF granule group and the placebo group, and recruit additional 10 healthy individuals as controls for mechanistic outcome. The two groups respectively take TXYF granule or placebo orally for treatment. The primary outcome is the response rate of IBS-Symptom Severity Score (IBS-SSS). The secondary outcomes include adequate relief (AR), IBS-Quality of Life Questionnaire (IBS-QOL), and long-term efficacy. Mechanistic outcome is the whole transcriptome profiling of the intestinal mucosae from IBS participants before and after the treatment and healthy individuals.

DISCUSSION

This trial will prove the effectiveness and safety of TXYF granule with high-quality evidence and provide a penetrating and comprehensive perspective on the molecular mechanism of IBS-D by whole transcriptome analysis, which makes us pinpoint specific biomarkers of IBS-D and therapeutic targets of TXYF.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR-IOR-1900021785 . Registered on 9 March 2019.

[Effect of moxibustion on TLR4/MyD88/NF-κB signaling pathway in colon of diarrhea-predo-minant irritable bowel syndrome rats]

OBJECTIVE

To observe the effect of moxibustion on serum inflammatory factors, Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and nuclear factor Kappa B (NF-κB) in colon tissue of rats with diarrhea-predominant irritable bowel syndrome (IBS-D)，so as to explore the mechanism of moxibustion in the treatment of IBS-D.

METHODS

Healthy male SD rats were randomly divided into blank group, model group and moxibustion group, with 8 rats in each group. The IBS-D model was established by chronic restraint combined with gavage of Senna-leaf solution. The rats of the moxibustion group was treated with moxibustion at "Tianshu"(ST25)and "Shangjuxu"(ST37)for 30 min， once a day for 7 d. After the intervention, the rate of loose stools and the minimum threshold volume of abdominal withdrawal reflex (AWR) induced by colorectal distension were observed. The contents of serum inflammatory factors IL-1β, TNF-α and IL-6 were detected by ELISA. The pathological changes of rat colon were observed by H.E. staining. The average optical density of TLR4 and NF-κB (p65) in colon tissue was detected by immunohistochemistry. The relative expressions of TLR4, MyD88 and NF-κB (p65) mRNAs in colon tissues were detected by real-time fluorescence quantitative PCR, and the expression levels of TLR4, MyD88 and NF-κB (p65) proteins in colon tissues were detected by Western blot.

RESULTS

There was a mild degree of inflammation in colon in rats of the model group. Compared with the blank group, the minimum volume threshold of AWR decreased significantly (P< 0.01), and the rate of loose stools, the contents of IL-1β, IL-6 and TNF-α in serum as well as the expressions of TLR4, MyD88, NF-κB (p65) mRNAs and protein in colon tissues were significantly increased in the model group (P<0.01). Compared with the model group, the inflammation was alleviated in colonic mucosa, the minimum volume threshold of AWR increased significantly (P<0.01), and rate of loose stools decreased significantly (P<0.01) in the moxibustion group, the contents of IL-1β, TNF-α and IL-6 in serum and the expression levels of TLR4, MyD88, NF-κB (p65) mRNAs and proteins in colon tissue decreased significantly in the moxibustion group (P<0.01).

CONCLUSION

Moxibustion ST25 and ST37 can improve diarrhea symptom and visceral hypersensitivity in IBS-D rats, which may be related with its effects in inhibiting TLR4/MyD88/NF-κB signaling pathway and reducing the expression of inflammatory factors.

[Effect of electroacupuncture on intestinal epithelial mucosal barrier function in rats with diarrhea-predominant irritable bowel syndrome]

OBJECTIVE

To observe the effect of electroacupuncture (EA) on intestinal epithelial mucosal barrier function in diarrhea-predominant irritable bowel syndrome(IBS-D) rats, so as to explore its mechanisms underlying improvement of IBS-D.

METHODS

Forty SD rats (half male and half female) were randomly divided into control, model, EA and medication (Pinaverium Bromide, PB) groups, with 10 rats in each group. The IBS-D model was established by chronic unpredictable mild stress combined with gavage of Senna-leaf solution. EA (2 Hz/15 Hz，0.1-1 mA) was applied to unilateral "Zusanli"(ST36),"Tianshu" (ST25), "Sanyinjiao"(SP6) and "Taichong"(LR3) alternatively for 15 min, once daily for 14 days. Rats of the medication group was treated by gavage of PB (10 mL·kg^-1·d^-1) for 14 days. The visceral sensitivity (pain) was assessed by using the pressure threshold which the inserted rectal balloon catheter air-inflation (connected to a blood pressure gauge) induced stronger abdominal muscular contraction to force the rat's abdomen to lift the experimental stand surface. The diarrhea index was used to evaluate loose stool grade. The expression of Claudin-1 and Occludin (intestinal epithelial tight junction proteins) of colon tissue was detected by immunohistochemistry. The activity of plasma diamine oxidase (DAO) was assayed by using spectrophotometry.

RESULTS

Compared with the control group, the diarrhea index and plasma DAO activity in the model group were significantly increased (P<0.01), while the visceral pain threshold, expression of Claudin-1 and Occludin in the model group were significantly decreased (P<0.01). After the treatment, the diarrhea index and plasma DAO activity were significantly lower in both EA and medication groups than that in the model group (P<0.01), and the visceral pain threshold and expression levels of Claudin-1 and Occludin were obviously increased (P<0.05, P<0.01). No significant differences were found between the EA and medication groups in all the above-mentioned indexes (P>0.05).

CONCLUSION

Electroacupuncture can significantly improve abdominal pain and diarrhea in IBS-D model rats, which may be closely associated with its effects in up-regulating the expression of intestinal epithelial tight junction proteins Claudin-1 and Occludin to restore the function of intestinal epithelial mucosal barrier.

Small intestinal bacterial overgrowth is associated with Diarrhea-predominant irritable bowel syndrome by increasing mainly Prevotella abundance

Objective: Diarrhea-predominant irritable bowel syndrome (IBS-D) is the main subtype of IBS, a chronic functional gastrointestinal disorder. Small intestinal bacterial overgrowth (SIBO), which is characterized by dysbiosis of the bowel, causes gastrointestinal symptoms quite similar to IBS-D. However, whether SIBO correlates with IBS-D and its further mechanism remain unknown.Materials and Methods: The study included 60 IBS-D patients that fulfilled Rome IV criteria and 60 healthy controls. All subjects were undergoing a lactose breath test (LBT) to diagnose SIBO. IBS-D patients were further assigned to negative SIBO (SIBO^-) subgroup and positive SIBO (SIBO⁺) subgroup to analyze the scores of symptoms and differences in the fecal microbiota.Results: The prevalence of SIBO in IBS-D patients was higher than that in healthy controls (51.7% vs. 16.7%, p ≤ .001). In addition, IBS-SSS in SIBO⁺ subgroup was significantly higher than SIBO^- subgroup (p = .015). The 16S rRNA analyses showed that composition and abundance of fecal microbiota were obviously different between the two subgroups. There was a remarkable increase in Prevotella in IBS-D patients, especially in IBS-D SIBO⁺ sufferers. Meanwhile, there were a moderately positive correlation of the abundance of Prevotella (rho = 0.458, p ≤ .001) with IBS-SSS.Conclusion: SIBO is associated with IBS-D, which may be related to alteration in the intestinal microbiota. These findings suggest the potent role of Prevotella in gastrointestinal symptoms between SIBO and IBS-D, thus provide a novel insight into the connection between SIBO and IBS-D.

Metabolomics analysis revealed metabolic changes in patients with diarrhea-predominant irritable bowel syndrome and metabolic responses to a synbiotic yogurt intervention

PURPOSE

Irritable bowel syndrome is a gastrointestinal disorder which can influence human metabolism. It has been demonstrated that probiotics are beneficial in controlling IBS. Thus, the main objective of the present study was to determine metabolic changes in response to diarrhea predominant irritable bowel syndrome (IBS-D) and to investigate the metabolic effects of a synbiotic intervention on serum, urine, and stool samples from IBS-D patients and healthy controls using proton nuclear magnetic resonance (¹HNMR).

METHODS

A ¹HNMR-based metabolomics study was conducted on urine and serum metabolites from 16 healthy and eight IBS-D participants at baseline and after 4 weeks of a synbiotic yogurt intervention.

RESULTS

At the baseline, serum acetoacetate, myo-inositol, and sarcosine concentrations were higher and threonine and methionine concentrations were lower in the IBS-D cohort than the control group. Moreover, Indoxyl-sulfate concentration of urine was lower and dimethylamine and taurine were higher in the IBS-D group. After intervention, serum concentration of ketone bodies decreased, choline, phenylalanine, and branched-chain amino acids increased in IBS-D group. Metabolomics analysis indicated a shift in one-carbon metabolism. Thus, the level of serum homocysteine was determined and found to be higher in the IBS-D cohort at baseline, and then decreased after the intervention.

CONCLUSION

IBS causes a shift in one-carbon metabolism and these changes can be reversed by a synbiotic intervention. An increase in the number of fecal Lactobacilli and an improvement in the health status of IBS-D patients were also observed in response to intervention.

Inhibitory effects of patchouli alcohol on stress-induced diarrhea-predominant irritable bowel syndrome

AIM

To elucidate the mechanism of patchouli alcohol (PA) in treatment of rat models of diarrhea-predominant irritable bowel syndrome (IBS-D).

METHODS

We studied the effects of PA on colonic spontaneous motility using its cumulative log concentration (3 × 10-7 mol/L to 1 × 10-4 mol/L). We then determined the responses of the proximal and distal colon segments of rats to the following stimuli: (1) carbachol (1 × 10-9 mol/L to 1 × 10-5 mol/L); (2) neurotransmitter antagonists including Nω-nitro-L-arginine methyl ester hydrochloride (10 μmol/L) and (1R*, 2S*)-4-[2-Iodo-6-(methylamino)-9H-purin-9-yl]-2-(phosphonooxy)bicyclo[3.1.0]hexane-1-methanol dihydrogen phosphate ester tetraammonium salt (1 μmol/L); (3) agonist α,β-methyleneadenosine 5'-triphosphate trisodium salt (100 μmol/L); and (4) single KCl doses (120 mmol/L). The effects of blockers against antagonist responses were also assessed by pretreatment with PA (100 μmol/L) for 1 min. Electrical-field stimulation (40 V, 2-30 Hz, 0.5 ms pulse duration, and 10 s) was performed to observe nonadrenergic, noncholinergic neurotransmitter release in IBS-D rat colon. The ATP level of Kreb's solution was also determined.

RESULTS

PA exerted a concentration-dependent inhibitory effect on the spontaneous contraction of the colonic longitudinal smooth muscle, and the half maximal effective concentration (EC50) was 41.9 μmol/L. In comparison with the KCl-treated IBS-D group, the contractile response (mg contractions) in the PA + KCl-treated IBS-D group (11.87 ± 3.34) was significantly decreased in the peak tension (P < 0.01). Compared with CCh-treated IBS-D rat colon, the cholinergic contractile response of IBS-D rat colonic smooth muscle (EC50 = 0.94 μmol/L) was significantly decreased by PA (EC50 = 37.43 μmol/L) (P < 0.05). Lack of nitrergic neurotransmitter release in stress-induced IBS-D rats showed contraction effects on colonic smooth muscle. Pretreatment with PA resulted in inhibitory effect on L-NAME-induced (10 μmol/L) contraction (P < 0.05). ATP might not be the main neurotransmitter involved in inhibitory effects of PA in the colonic relaxation of stress-induced IBS-D rats.

CONCLUSION

PA application may serve as a new therapeutic approach for IBS-D.

Modified Shenling Baizhu powder combined with electroacupuncture for treatment of diarrhea-predominant irritable bowel syndrome: Effect on clinical symptoms and psychological state

AIM

To evaluate the safety and efficacy of modified Shenling Baizhu powder combined with electroacupuncture (EA) in the treatment of diarrhea-predominant irritable bowel syndrome (D-IBS) with regard to the improvement of clinical symptoms and psychological state.

METHODS

Seventy D-IBS patients were randomly divided into an observation group and a control group (n = 35 each). The observation group was treated with modified Shenling Baizhu powder combined with EA at Tianshu (ST25), Shangjuxu (ST37), Zusanli (ST36), Sanyinjia (SP6), Taichong (LR3), Baihui (GV20), 30 min for each treatment, 5 times a week, for 4 wk. The control group were treated with maleic acid trimebutine, 0.1 g each time, three times a day, for 4 wk. The irritable bowel syndrome symptom severity score (IBS-SSS), irritable bowel syndrome quality of life (IBS-QOL), and symptom check list-90 (SCL-90) were sued to evaluate the clinical symptoms, quality of life, and psychological symptoms in the two groups before treatment, after 4 wk of treatment, and at 4 wk after treatment, respectively. Drug adverse reactions were also recorded.

RESULTS

The clinical curative effect was 97.1% in the observation group and 91.4% in the control group. After 4 wk of treatment, the degree and frequency of abdominal pain and overall IBS-SSS score was significantly better (P < 0.05), and anxiety was more significantly improved in the observation group than in the control group. At 4 wk after treatment, the scores of anxiety, somatic mind, physical role, and health concerns were improved more significantly in the observation group than in the control group (P < 0.05), with anxiety and health concerns improved most prominently (P < 0.01). SCL-90 symptoms showed no statistically significant difference between the two groups before treatment (P > 0.05); however, at 4 wk after treatment, there was a significant difference between the two groups with regard to somatization score (P < 0.05).

CONCLUSION

Modified Shenling Baizhu powder combined with EA can significantly improve the clinical symptoms and psychological status of D-IBS patients, without obvious adverse reactions.

Downregulation of mucosal mast cell activation and immune response in diarrhoea-irritable bowel syndrome by oral disodium cromoglycate: A pilot study

BACKGROUND AND GOAL

Diarrhoea-predominant irritable bowel syndrome (IBS-D) exhibits intestinal innate immune and mucosal mast cell (MC) activation. MC stabilisers have been shown to improve IBS symptoms but the mechanism is unclear. Our primary aim was to investigate the effect of oral disodium cromoglycate (DSCG) on jejunal MC activation and specific innate immune signalling pathways in IBS-D, and secondarily, its potential clinical benefit.

STUDY

Mucosal MC activation (by ultrastructural changes, tryptase release and gene expression) and innate immune signalling (by protein and gene expression) were quantified in jejunal biopsies from healthy (HS; n = 16) and IBS-D subjects after six months of either treatment with DSCG (600 mg/day, IBS-D-DSCG group; n = 18) or without treatment (IBS-D-NT group; n = 25). All IBS-D patients recorded abdominal pain and bowel habits at baseline and in the last 10 days prior to jejunal sampling.

RESULTS

IBS-D-NT exhibited significant MC activation and over-expression of immune-related genes as compared to HS, whereas in IBS-D-DSCG MC activity and gene expression were similar to HS. Furthermore, DSCG significantly reduced abdominal pain and improved stool consistency.

CONCLUSION

Oral DSCG modulates mucosal immune activity and improves gut symptoms in IBS-D patients. Future placebo-controlled clinical trials are needed for confirmation of clinical benefit of DSCG for IBS-D.

Regulating effect of TongXie-YaoFang on colonic epithelial secretion via Cl- and HCO3- channel

AIM

To investigate the pharmacological effect of TongXie-YaoFang (TXYF) formula, a Chinese herbal formula, on Diarrhea-predominant irritable bowel syndrome (D-IBS) rats.

METHODS

In a neonatal maternal separation plus restraint stress (NMS + RS) model of D-IBS, male Sprague Dawley rats were randomly divided into two groups (NMS + RS group and TXYF-formula group) with no handlings were used as controls (NH group). Starting from postnatal day 60, rats in TXYF-formula group were administered TXYF-formula (4.92 g/100 g bodyweight) orally twice a day for 14 consecutive days while NH group and NMS + RS group were given distilled water. Using short-circuit current technology, we observed 5-HT-induced changes of current across ion channels, such as cystic fibrosis transmembrane conductance regulator (CFTR) Cl^- channel, epithelial Na⁺ channel (ENaC), Ca²⁺-dependent Cl^- channel (CACC), Na⁺-K⁺-2Cl^- co-transporter (NKCC), and Na⁺-HCO₃^- co-transporter (NBC), in the colonic epithelium of three groups after exposure to drugs and specific blockers with a Power Lab System (AD Instruments International).

RESULTS

Under basal conditions, the changes of short-circuit current (∆Isc, µA/cm²) induced by 5-HT were similar in NH group and TXYF-formula group, and both higher than NMS + RS group (70.86 µA/cm² ± 12.32 µA/cm², 67.67 µA/cm² ± 11.68 µA/cm² vs 38.8 µA/cm² ± 7.25 µA/cm², P < 0.01, respectively). When CACC was blocked by 4,4′-diisothiocyanato-stilbene-2,2′-disulfonic acid, 5-HT-induced ∆Isc was smaller in NMS + RS group than in NH group and TXYF-formula group, respectively (48.41 µA/cm² ± 13.15 µA/cm² vs 74.62 µA/cm² ± 10.73 µA/cm², 69.22 µA/cm² ± 11.7 µA/cm², P < 0.05, respectively). The similar result could be obtained when ENaC was blocked by Amiloride (44.69 µA/cm² ± 12.58 µA/cm² vs 62.05 µA/cm² ± 11.26 µA/cm², 62.11 µA/cm² ± 12.01 µA/cm², P < 0.05, respectively). However, when CFTR Cl^- channel was blocked by 1,1-dimethyl piperidinium chloride (DPC), 5-HT-induced ∆Isc did not significantly differ in three groups (42.28 µA/cm² ± 10.61 µA/cm² vs 51.48 µA/cm² ± 6.56 µA/cm² vs 47.75 µA/cm² ± 7.99 µA/cm², P > 0.05, respectively). The similar results could also be obtained in three groups when NBC and NKCC were respectively blocked by their blockers.

CONCLUSION

TXYF-formula can regulate the Cl^- and HCO₃^- secretion of colonic mucosa via CFTR Cl^- channel, Cl^-/HCO₃^- exchanger, NBC and NKCC co-transporters.

Comparison of 5-hydroxytryptophan signaling pathway characteristics in diarrhea-predominant irritable bowel syndrome and ulcerative colitis

AIM: To study differences in the visceral sensitivity of the colonic mucosa between patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and those with ulcerative colitis (UC) in remission and to relate these differences with changes in the 5-hydroxytryptophan (5-HT) signaling pathway.

METHODS: Gastrointestinal symptoms were used to determine the clinical symptom scores and rectal visceral sensitivity of patients with IBS-D and patients with UC in remission. Blood levels of 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) were measured using an HPLC-electrochemical detection system. The levels of 5-HT 3 receptor (3R), 4R, and 7R mRNAs in colonic biopsy samples were detected using reverse transcription-polymerase chain reaction. The protein expression of TPH1 was analyzed by Western blot and immunohistochemistry.

RESULTS: Abdominal pain or discomfort, stool frequency, and the scores of these symptoms in combination with gastrointestinal symptoms were higher in the IBS-D and UC groups than in the control groups. However, no significant differences were observed between the IBS-D and UC remission groups. With respect to rectal visceral sensitivity, the UC remission and IBS-D groups showed a decrease in the initial perception threshold, defecating threshold and pain threshold. However, these groups exhibited significantly increased anorectal relaxation pressure. Tests examining the main indicators of the 5-HT signaling pathway showed that the plasma 5-HT levels, 5-HIAA concentrations, TPH1 expression in the colonic mucosa, and 5-HT3R and 5-HT5R expression were increased in both the IBS-D and the UC remission groups; no increases were observed with respect to 5-HT7R expression.

CONCLUSION: The IBS-D and UC groups showed similar clinical symptom scores, visceral sensitivity, and levels of serotonin signaling pathway indicators in the plasma and colonic mucosa. However, the pain threshold and 5-HT7R expression in the colonic mucosa were significantly different between these groups. The results reveal that (1) IBS-D and UC are related to visceral sensitivity pathogenesis and the clinical manifestations of these conditions and (2) the observed differences in visceral hypersensitivity are possibly due to differences in levels of the 5-HT7 receptor, a component of the 5-HT signaling pathway.

Influence of Jianpi Huashi granule on 5-HT, 5-HTR3, and 5-HTR4 expression in the brain of rats with diarrhea-predominant irritable bowel syndrome

AIM: To investigate the effect of Jianpi Huashi granule on 5-hydroxytryptamine (5-HT), 5-hydroxytryptamine receptor 3 (5-HTR3), and 5-HTR4 expression in the brain of rats with diarrhea-predominant irritable bowel syndrome (D-IBS) to evaluate their implications in the therapeutic effects of Jianpi Huashi granule in improving colonic motility and visceral sensitivity.

METHODS: A rat model of D-IBS was established by intragastric administration of Sennae decoction combined with restraint stress. Rats were divided into several groups. Jianpi Huashi granule was given to rats in Jianpi Huashi groups, Pinaverium bromide tablets to rats in the positive group and water to the other groups. ELISA was used to detect the content of 5-HT in the hippocampus. Immunohistochemistry assay was used to detect the expression of 5-HT, 5-HTR3, and 5-HTR4 in the prefrontal cortex, hippocampus, and hypothalamus. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA expression of 5-HTR3 and 5-HTR4 in the hippocampus.

RESULTS: In the D-IBS model group, the content of 5-HT in the hippocampus (327.30 ± 22.35 vs 265.33 ± 13.60) and the expression of 5-HT in the prefrontal cortex, hippocampus, hypothalamus (0.16 ± 0.02 vs 0.08 ± 0.01, 0.19 ± 0.02 vs 0.09 ± 0.01, 0.17 ± 0.02 vs 0.08 ± 0.01, P < 0.01 for all) were increased significantly compared to the normal group. The expression of 5-HTR3 (0.29 ± 0.02 vs 0.10 ± 0.01, 0.23 ±0.02 vs 0.09 ± 0.01, 0.22 ± 0.02 vs 0.09 ± 0.02, P < 0.01 for all) and 5-HTR4 (0.25 ± 0.02 vs 0.11 ± 0.01, 0.28 ± 0.02 vs 0.10 ± 0.02, 0.27 ± 0.02 vs 0.11 ± 0.02, P < 0.01 for all) in the prefrontal cortex, hippocampus and hypothalamus, and the expression of 5-HTR3 and 5-HTR4 mRNAs (0.54 ± 0.01 vs 0.17 ± 0.05, 0.73 ± 0.08 vs 0.10 ± 0.02, P < 0.01 for all) in the hippocampus were significantly increased in the model group compared with the normal group. After treatment, the contents of 5-HT in the hippocampus in the positive control group, medium- and high-dose Jianpi Huashi granule groups were significantly decreased (298.92 ± 12.16, 286.29 ± 24.43, 279.86 ± 20.05 vs 327.30 ± 22.35, P < 0.05, P < 0.01), the expression of 5-HT in the prefrontal cortex in medium- and high-dose Jianpi Huashi granule groups was significantly reduced (0.12 ± 0.01, 0.11 ± 0.01 vs 0.16 ± 0.02, P < 0.01 for both), and the expression of 5-HT in the hippocampus and hypothalamus in the positive control group, medium- and high-dose Jianpi Huashi granule groups was significantly decreased. The expression of 5-HTR3 mRNA in the hippocampus in all treatment groups was significantly reduced.

CONCLUSION: Jianpi Huashi granule regulates colonic motility and visceral sensitivity in rats with D-IBS possibly by modulating the expression of 5-HT, 5-HTR3, and 5-HTR4 in the brain.

Nerve growth factor and diarrhea-predominant irritable bowel syndrome (IBS-D): a potential therapeutic target?

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder characterized by recurrent abdominal pain or discomfort associated with abnormal bowel habits. Diarrhea-predominant IBS (IBS-D) is a major subtype of IBS, the predominant manifestations of which are abdominal pain and diarrhea. The pathogenesis of IBS-D remained unknown until recently. The effects of psychosocial stress, central hypervigilance, neuroendocrine abnormality, disturbed gastrointestinal motility, mucosal immune activation, intestinal barrier dysfunction, visceral hypersensitivity (VH), altered gut flora, and genetic susceptibility may be involved in its development. Recently, increased attention has been placed on the neural-immune-endocrine network mechanism in IBS-D, especially the role of various neuroendocrine mediators. As a member of the neurotrophin family, nerve growth factor (NGF) has diverse biological effects, and participates in the pathogenesis of many diseases. Basic studies have demonstrated that NGF is associated with inflammatory- and stress-related VH, as well as stress-related intestinal barrier dysfunction. The aim of this study is to summarize recent literature and discuss the role of NGF in the pathophysiology of IBS-D, especially in VH and intestinal barrier dysfunction, as well as its potential as a therapeutic target in IBS-D.

Influence of Jianpi Huashi granule on CRF and CRFR1 expression in the brain-gut axis of rats with diarrhea-predominant irritable bowel syndrome

AIM: To evaluate the effect of Jianpi Huashi granule on corticotropin releasing factor (CRF) and corticotropin releasing factor receptor 1 (CRFR1) expression in the colon, hippocampus and hypothalamus of rats with diarrhea-predominant irritable bowel syndrome (D-IBS).

METHODS: A rat model of D-IBS was established by intragastric administration of Sennae decoction combined with restraint stress. Rats were divided into several groups. Jianpi Huashi granule was given to rats in Jianpi Huashi groups, pinaverium bromide tablets to rats in the positive group and water to the other groups. ELISA was used to detect the content of CRF in the colon. Immunohistochemistry assay was used to detect the expression of CRFR1 in the colon, hippocampus, and hypothalamus, and CRF in the hippocampus and hypothalamus. RT-PCR was used to detect the expression of CRF and CRFR1 mRNAs in the colon and hippocampus.

RESULTS: In the D-IBS model group, the content of CRF in the colon (67.1 ± 3.8 vs 36.0 ± 3.0) and the expression of CRF in the hippocampus and hypothalamus (0.23 ± 0.02 vs 0.09 ± 0.01, 0.17 ± 0.02 vs 0.09 ± 0.01) were increased significantly compared to the normal group (P < 0.01 for all). The expression of CRFR1 in the colon, hippocampus and hypothalamus was also increased significantly (0.17 ± 0.01 vs 0.03 ± 0.01, 0.20 ± 0.02 vs 0.09 ± 0.01, 0.19 ± 0.02 vs 0.07 ± 0.01, P < 0.01 for all). The expression of CRF and CRFR1 mRNAs in the colon and hippocampus was significantly increased in the model group compared to the normal group (0.89 ± 0.04 vs 0.09 ± 0.01, 1.09 ± 0.09 vs 0.21 ± 0.04, 0.56 ± 0.01 vs 0.15 ± 0.05, 1.26 ± 0.14 vs 0.23 ± 0.06, P < 0.01 for all). After treatment, the expression of CRF in the colon and hippocampus in all treatment groups was significantly decreased (51.0 ± 3.4, 54.6 ± 4.1, 45.1 ± 4.7, 43.3 ± 3.9 vs 67.1 ± 3.8; 0.18 ± 0.02, 0.19 ± 0.02, 0.15 ± 0.02, 0.11 ± 0.01 vs 0.23 ± 0.02, P < 0.01 for all), and the expression of CRF in the positive control group, medium- and high-dose Jianpi Huashi granule groups in the hypothalamus was significantly decreased (0.15 ± 0.02, 0.13 ± 0.01, 0.12 ± 0.01 vs 0.17 ± 0.02, P < 0.05 or P < 0.01). The expression of CRFR1 in the colon, hippocampus and hypothalamus in the positive control group, medium- and high-dose Jianpi Huashi granule groups was significantly reduced (0.10 ± 0.01, 0.08 ± 0.01, 0.05 ± 0.01 vs 0.17 ± 0.01, 0.16 ± 0.01, 0.14 ± 0.02, 0.13 ± 0.01 vs 0.20 ± 0.02, 0.15 ± 0.02, 0.13 ± 0.01, 0.11 ± 0.01 vs 0.19 ± 0.02, P < 0.05 or P < 0.01). The expression of CRF mRNA in the colon in all treatment groups was significantly reduced (0.63 ± 0.04, 0.76 ± 0.06, 0.32 ± 0.06, 0.13 ± 0.03 vs 0.89 ± 0.04, P < 0.01 for all), while the expression of CRF mRNA in the hippocampus in the medium- and high-dose Jianpi Huashi granule groups was significantly decreased (0.76 ± 0.11, 0.67 ± 0.10 vs 1.09 ± 0.09, P < 0.01 for all). The expression of CRFR1 mRNA in the colon in the positive control group, medium- and high-dose Jianpi Huashi granule groups was significantly reduced (0.47 ± 0.03, 0.40 ± 0.06, 0.24 ± 0.06 vs 0.56 ± 0.01, P < 0.05 or P < 0.01), while the expression of CRFR1 mRNA in the hippocampus in the medium- and high-dose Jianpi Huashi granule groups was significantly decreased (0.62 ± 0.06, 0.60 ± 0.07 vs 1.26 ± 0.14, P < 0.01 for all).

CONCLUSION: Jianpi Huashi granule regulates colonic motility and visceral sensitivity in rats with D-IBS possibly by modulating the expression of CRF and CRFR1 in the colon, hippocampus and hypothalamus.

Influence of Jianpi Huashi granule on colonic motility and c-fos expression in the central nerve system in rats with diarrhea-predominant irritable bowel syndrome

AIM: To evaluate the effect of Jianpi Huashi granule on colonic motility and c-fos expression in the central nerve system in rats with diarrhea-predominant irritable bowel syndrome (D-IBS).

METHODS: A rat model of D-IBS was established by intragastric administration of Sennae decoction combined with restraint stress. Rats were divided into several groups. Jianpi Huashi granule was given to rats in Jianpi Huashi groups, pinaverium bromide tablets to rats in the positive group and water to the other groups. Maclab/4e 4-channel physiology recorder was used to record colon motion curves and evaluate colonic motility using motility index. Immunohistochemistry assay was used to detect the expression of c-fos in the spinal horn, prefrontal cortex, hippocampus and hypothalamus. ELISA was used to detect the contents of c-fos and 5-hydroxytryptamine in the spinal cord and hippocampus.

RESULTS: In the D-IBS model group, the colonic motility index increased significantly compared to the normal group (939.01 ± 91.96 vs 574.78 ± 53.33, P < 0.01). The expression of c-fos in the spinal horn, prefrontal cortex, hippocampus and hypothalamus was significantly increased in the model group compared to the normal group (0.25 ± 0.03 vs 0.08 ± 0.01, 0.15 ± 0.02 vs 0.06 ± 0.01, 0.23 ± 0.02 vs 0.08 ± 0.02, 0.16 ± 0.02 vs 0.07 ± 0.01, P < 0.01 for all). The contents of c-fos in the spinal cord and hippocampus were increased significantly in the model group compared to the normal group (19.68 ± 1.17 vs 11.10 ± 2.59, 12.32 ± 1.22 vs 5.38 ± 0.88, P < 0.01 for both). After treatment, the colonic motility index in the medium- and high-dose Jianpi Huashi granule groups was significantly decreased (731.91 ± 67.34, 695.20 ± 80.58 vs 939.01 ± 91.96, P < 0.01 for both), the expression of c-fos was significantly reduced (0.14 ± 0.02, 0.10 ± 0.01 vs 0.25 ± 0.03; 0.11 ± 0.01, 0.09 ± 0.02 vs 0.15 ± 0.02; 0.16 ± 0.01, 0.12 ± 0.01 vs 0.23 ± 0.02; 0.12 ± 0.01, 0.09 ± 0.01 vs 0.16 ± 0.02, P < 0.01 for all), and the content of c-fos was also significantly decreased (16.02 ± 1.58, 15.62 ± 1.64 vs 19.68 ± 1.17; 8.53 ± 2.05, 7.28 ± 1.54 vs 12.32 ± 1.22, P < 0.01 for all).

CONCLUSION: Jianpi Huashi granule regulates colonic motility in rats with D-IBS possibly by modulating the expression of c-fos in the central nerve system.

Factorial study of moxibustion in treatment of diarrhea-predominant irritable bowel syndrome

AIM: To identify an appropriate therapeutic regimen for using aconite cake-separated moxibustion to treat diarrhea-predominant irritable bowel syndrome (D-IBS).

METHODS: A factorial design was employed to examine the two factors of moxibustion frequency and number of cones. The two tested frequencies were three or six moxibustion sessions per week, and the two tested doses were one or two cones per treatment. A total of 166 D-IBS patients were randomly divided into four treatment groups, which included each combination of the examined frequencies and doses. The bilateral Tianshu acupoints (ST25) and the Qihai acupoint (RN6) were selected for aconite cake-separated moxibustion. Each patient received two courses of treatment, and each course had a duration of 2 wk. For each group, the scores on the Birmingham irritable bowel syndrome (IBS) symptom questionnaire, the IBS Quality of Life scale, the Self-Rating Depression Scale (SDS), the Self-Rating Anxiety Scale (SAS), the Hamilton Depression (HAMD) scale, and the Hamilton Anxiety (HAMA) scale were determined before treatment, after the first course of treatment, and after the second course of treatment.

RESULTS: The symptom, quality of life, SDS, SAS, HAMD, and HAMA scores of the patients in all 4 aconite cake-separated moxibustion groups were significantly lower after the first and second courses of treatment than before treatment (P < 0.001 for all). The symptom, quality of life, SDS, SAS, HAMD, and HAMA scores of the patients in all four aconite cake-separated moxibustion groups were significantly lower after the second course of treatment than after the first course of treatment (P < 0.001 for all). Between-group comparisons after the second course of treatment revealed that the symptom scores for group 1 (1 cone, 3 treatments/wk) and group 3 (2 cones, 3 treatments/wk) were significantly lower than that for group 2 (1 cone, 6 treatments/wk) (5.55 ± 5.05 vs 10.45 ± 6.61, P < 0.001; 5.65 ± 4.00 vs 10.45 ± 6.61, P < 0.001). Regarding the two levels of the two examined factors for aconite cake-separated moxibustion, after the first course of treatment, the changes in HAMA scores were significantly different for the two tested moxibustion frequencies (P = 0.011), with greater changes for the “6 treatments/wk” groups than for the “3 treatments/wk” groups; in addition, there were interaction effects between the number of cones and moxibustion frequency (P = 0.028). After the second course of treatment, changes in symptom scores for the 2 tested moxibustion frequencies were significantly different (P = 0.002), with greater changes for the “3 treatments/wk” groups than for the “6 treatments/wk” groups.

CONCLUSION: An aconite cake-separated moxibustion treatment regimen of 3 treatments/wk and 1 cone/treatment appears to produce better therapeutic effects for D-IBS compared with the other tested regimens.

Association between HTR3E gene polymorphism and intestinal symptoms of diarrhea-predominant irritable bowel syndrome in Chinese women

AIM: To investigate the relationship between 5-hydroxytryptamine-3 E receptor (HTR3E) gene polymorphism and intestinal symptoms of diarrhea-predominant irritable bowel syndrome (IBS-D) in Chinese women.

METHODS: Polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique was used to detect the 3'UTR variant c.*76G>A of the HTR3E gene in 300 healthy female subjects and 294 female IBS-D patients.

RESULTS: There were significant differences between the IBS-D patients and controls in the frequencies of the GA genotype (χ² = 6.362, P = 0.012) and the A allele (χ² = 5.970, P = 0.015). Compared with the GG genotype of HTR3E, the patients with GA genotype had a higher frequency of defecation (χ² = 7.68, P = 0.021) and more serious stool form (χ² = 6.225, P = 0.044).

CONCLUSION: The GA genetype of HTR3E might be an important predisposing factor for IBS-D in Chinese females and might contribute to the deterioration of the intestinal symptoms.

Microscopic colitis: Common cause of unexplained nonbloody diarrhea

Microscopic colitis (MC) is characterized by chronic, watery, secretory diarrhea, with a normal or near normal gross appearance of the colonic mucosa. Biopsy is diagnostic and usually reveals either lymphocytic colitis or collagenous colitis. The symptoms of collagenous colitis appear most commonly in the sixth decade. Patients report watery, nonbloody diarrhea of a chronic, intermittent or chronic recurrent course. With collagenous colitis, the major microscopic characteristic is a thickened collagen layer beneath the colonic mucosa, and with lymphocytic colitis, an increased number of intraepithelial lymphocytes. Histological workup can confirm a diagnosis of MC and distinguish the two distinct histological forms, namely, collagenous and lymphocytic colitis. Presently, both forms are diagnosed and treated in the same way; thus, the description of the two forms is not of clinical value although this may change in the future. Since microscopic colitis was first described in 1976 and only recently recognized as a common cause of diarrhea, many practicing physicians may not be aware of this entity. In this review, we outline the epidemiology, risk factors associated with MC, its etiopathogenesis, the approach to diagnosis and the management of these individuals.

Effect of Changjitai decoction on expression of substance P mRNA in the colonic mucosa and hypothalamus of rats with diarrhea-predominant irritable bowel syndrome

AIM: To detect the expression of substance P (SP) mRNA in the colonic mucosa and hypothalamus of rats with diarrhea-predominant irritable bowel syndrome (IBS-D), and to assess the therapeutic effect of traditional Chinese medicine Changjitai decoction on visceral hypersensitivity in rats with IBS-D.

METHODS: Sixty male Sprague-Dawley rats were equally and randomly divided into six groups: normal group, model control group, dicetel group, low-, medium-, and high-dose Changjitai groups. IBS-D was induced by restraint stress for 2 wk combined with intragastric administration of 2 mL of Radix Rhizoma Rhei leachate from the third day in rats of all groups except the normal group. After treatment with corresponding drug for 2 wk, rats in the model group and treatment groups underwent colorectal distention immediately and then killed. The changes in defecation were monitored by measuring fecal pellets. The expression of SP mRNA in the hypothalamus and colon was detected by RT-PCR.

RESULTS: In the model control group, the frequency of defecation increased obviously compared to the normal group, and the characteristics of stools deteriorated simultaneously. The expression of SP mRNA in the hypothalamus and colon was significantly increased in the model group compared to the normal group (0.988 ± 0.192 vs 0.606 ± 0.151, P < 0.01; 1.042 ± 0.293 vs 0.768 ± 0.116, P < 0.05). After treatment with Changjitai decoction or diceter, the frequency of defecation and the characteristics of stools ameliorated significantly (13, 17, 14 vs 24, P < 0.05). There were no significantly differences in the above parameters between the Changjitai groups and dicetel group. SP mRNA levels were significantly reduced in the Changjitai decoction groups compared to the model control group (hypothalamus: 0.678 ± 0.103, 0.733 ± 0.103 vs 0.988 ± 0.192, P < 0.01; colon: 0.546 ± 0.278, 0.500 ± 0.260 vs 1.042 ± 0.293, both P < 0.01; 0.731 ± 0.199 vs 1.042 ± 0.293, P < 0.05).

CONCLUSION: Changjitai decoction relieves diarrhea symptoms, ameliorates the stress state, inhibits bowel motility, and reduces visceral hypersensitivity in rats with IBS-D possibly by modulating the expression of SP mRNA in the hypothalamus and colon.

Relationship among food intolerance, severity of symptoms and the number of mast cells in the ileocecal junction in patients with diarrhea-predominant irritable bowel syndrome

AIM: To analyze the relationship among food intolerance, severity of symptoms and the number of mucosal mast cells (MCs) in the ileocecal junction (ICJ) in patients with diarrhea-predominant irritable bowel syndrome (D-IBS), and to explore the influence of food intolerance on the pathogenesis of D-IBS.

METHODS: Twenty-two patients with D-IBS fulfilling the Rome III criteria and 21 asymptomatic healthy controls underwent colonoscopy in which two adjacent biopsy samples were taken from the ICJ. Mucosal MCs were detected by toluidine blue staining. The Food Intolerance Questionnaire was used to evaluate the perceived food intolerance status of D-IBS patients and controls. The Functional Bowel Disorder Severity Index (FBDSI) and IBS Symptom Severity Scale (IBS-SSS) were used to evaluate the severity of symptoms in D-IBS patients. The relationship among the scores of FBDSI and IBS-SSS, the number of MCs and the scores of food intolerance in D-IBS patients was analyzed.

RESULTS: The number of mucosal MCs in the ICJ was significantly higher in patients with D-IBS than in controls (4.68 ± 0.55/HP vs 1.33 ± 0.54/HP, P < 0.001). Compared to controls, perceived FI was more frequent in patients with D-IBS (P < 0.05). The scores of FBDSI and IBS-SSS were positively correlated with that of food intolerance in D-IBS patients (FBDSI: r = 0.992, P < 0.001; IBS-SSS: r = 0.970, P < 0.001), and with the number of mucosal MCs in the ICJ (FBDSI: r = 0.957, P < 0.001; IBS-SSS: r = 0.985, P < 0.001). The scores of food intolerance in D-IBS patients were positively correlated with the number of mucosal MCs in the ICJ (r = 0.964, P < 0.001). The number of mucosal MCs in the ICJ were significantly higher in healthy subjects with self-reported food intolerance than in those without food intolerance (P < 0.05).

CONCLUSION: The symptoms of D-IBS are positively correlated with increased number of enteric mucosal MCs which might be caused by food antigen. Food intolerance is more frequent in D-IBS patients than in controls. D-IBS symptoms may be caused or exacerbated by food intolerance.

Eye acupuncture therapy up-regulates aquaporin 3 expression in the colon of rats with diarrhea-predominant irritable bowel syndrome

AIM: To explore mechanisms underlying therapeutic effects of eye acupuncture against diarrhea-predominant irritable bowel syndrome (D-IBS) by investigating the expression of vasoactive intestinal peptide (VIP) and aquaporin 3 (AQP3) in the colon of D-IBS rats.

METHODS: Thirty male Wistar rats were randomly divided into three groups: control group, D-IBS model group, and eye acupuncture group. D-IBS was induced in rats of the D-IBS model group and eye acupuncture group by chronic stress and constraint. The eye acupuncture group underwent eye acupuncture therapy for 7 d. VIP mRNA expression in the colon was detected by RT-PCR. The mRNA and protein expression of AQP3 in the colon was detected by immunohistochemistry and real-time PCR, respectively.

RESULTS: Compared to the control group, the mRNA expression level of VIP in the colon was increased significantly (0.94 ± 0.07 vs 0.64 ± 0.15, P < 0.01) and the mRNA and protein expression levels of AQP3 in the colon were remarkably decreased (1.09 ± 0.09 vs 7.02 ± 1.25; 0.284 ± 0.020 vs 0.601 ± 0.027, both P < 0.01) in the D-IBS model group. Eye acupuncture therapy remarkably decreased the mRNA expression of VIP (0.78 ± 0.15 vs 0.94 ± 0.07, P < 0.01) but significantly increased the mRNA and protein expression of AQP3 (2.33 ± 0.66 vs 1.09 ± 0.09; 0.374 ± 0.03 vs 10.284 ± 0.020, both P < 0.01) in D-IBS rats.

CONCLUSION: Oversecretion of VIP and hyposerection of AQP3 may be involved in the pathogenesis of D-IBS. Eye acupuncture therapy exerts therapeutic effects against D-IBS in rats possibly by down-regulating VIP expression and up-regulating AQP3 expression in the colon.

Acupuncture treatment of diarrhea-predominant irritable bowel syndrome: a randomized controlled trial

AIM: To evaluate the clinical effect of acupuncture treatment for diarrhea-predominant irritable bowel syndrome (D-IBS).

METHODS: This is a prospective, randomized, controlled trial. According to diagnostic criteria and selection criteria, 120 patients were randomized into two equal groups: intervention group and control group. The intervention group underwent acupuncture therapy and pinaverium treatment, while the control group underwent sham acupuncture and pinaverium treatment. The period of treatment is four weeks. After treatment for 2 and 4 wk, the changes of symptoms, including abdominal pain, abdominal distension, and stool characters, were observed and serum vasoactive intestinal peptide (VIP) levels were measured by ELISA.

RESULTS: The total response rate was significantly higher in the intervention group than in the control group (96% vs 76%, P < 0.05). The improvement in abdominal pain, abdominal distension, and stool characters was more significant in the intervention group than in the control group (1.32 ± 0.17 vs 3.37 ± 0.49, P = 0.000; 0.95 ± 0.06 vs 3.34 ± 0.24, P = 0.000; 0.48 ± 0.15 vs 3.64 ± 0.78 , P = 0.000). Before treatment, there is no significant difference in serum VIP levels between the two groups. However, after treatment, serum VIP levels in the intervention group were significantly lower than those in the control group (42.72 μg/L ± 12.78 μg/L vs 102.72 μg/L ± 21.23 μg/L, P = 0.000) .

CONCLUSION: Acupuncture treatment can relieve gastrointestinal symptoms and exert a treatment effect on D-IBS possibly by regulating VIP secretion.

Urgency as an Endpoint in Irritable Bowel Syndrome

BACKGROUND

The choice of endpoints is crucial for proper evaluation of agents in clinical trials of irritable bowel syndrome (IBS). In a recently published draft guidance for IBS from the United States Food and Drug Administration (FDA), urgency was not considered an appropriate primary endpoint. The FDA's position is that it is not clear how patients with diarrhea-predominant IBS (D-IBS) "define or describe urgency". The aims of this study were to evaluate the association of urgency with stool frequency and consistency in patients with D-IBS and to describe results from patient interviews on their understanding of the term urgency.

METHODS

A retrospective analysis of clinical trial data in patients with D-IBS was conducted. Analyses focused on the relationship of urgency to stool frequency and consistency. Interviews were conducted with patients with D-IBS to test their understanding of the term urgency.

RESULTS

On the days that patients reported urgency, as compared to the days that patients did not report urgency, they had more frequent bowel movements (3.9 versus 1.8) and looser stools (Bristol Stool Score: 5.4 versus 4.2). The differences for both parameters, evaluated on the days with or without urgency, were statistically significant. In patient interviews, patients with D-IBS had a clear understanding of the concept and terminology of urgency and considered it one of their two most bothersome symptoms.

CONCLUSIONS

Urgency should be considered a suitable co-primary endpoint in D-IBS studies.

Huangshu Enema down-regulates VIP expression in the colonic mucosa of rats with diarrhea-predominant irritable bowel syndrome

AIM: To investigate the effect of Chinese medicine Huangshu Enema (HSE) on the expression of vasoactive intestinal polypeptide (VIP) in the colonic mucosa of rats with diarrhea-predominant irritable bowel syndrome (D-IBS) and to explore possible mechanisms involved.

METHODS: Forty-eight female Sprague-Dawley rats were randomly divided into normal control group, model group, HSE treatment group and dicetel treatment group (n = 12 for each group). D-IBS was induced in rats by intragastric administration of senna decoction and restraint stress. The expression of VIP in the colonic mucosa of rats was determined by immunohistochemistry.

RESULTS: The number of VIP-positive cells and VIP staining intensity in the colonic mucosa of rats were significantly higher in the model group than in the normal control group (21.06 ± 2.69 vs 6.25 ± 2.08, t = 17.4216, P < 0.01; 2.43 ± 0.63 vs 0.63 ± 0.62, t = 6.5223, P < 0.01), in the model group than in the two treatment groups (t = 11.6697 and 5.5119; t = 6.0910 and 2.1575, respectively; both P < 0.01), and in the dicetel treatment group than in the HSE treatment group (10.62 ± 2.36 vs 15.31 ± 2.65, t = 5.2876, P < 0.01; 1.25 ± 0.58 vs 1.93 ± 0.68, t = 2.9272, P < 0.01).

CONCLUSION: HSE can reduce the number of VIP-positive cells and VIP staining intensity in the colonic mucosa of D-IBS rats and thereby exerts therapeutic effects against D-IBS.

Establishment and evaluation of a rat IBS model induced by intracolonic instillation of acetic acid and restraint stress

AIM: To explore the method to establish a rat model of diarrhea-predominant irritable bowel syndrome and to provide experimental evidence for future research.

METHODS: Forty male Wistar rats were divided into four groups: IBS1 group, IBS2 group, positive group and normal control group. A rat model of IBS was established by intracolonic instillation of acetic acid and restraint stress and using Williams method. Visceral hypersensitivity was evaluated by abdominal with-drawal reflex and abdominal electrical activity, while histological diversification was evaluated by histological examination.

RESULTS: Visceral hypersensitivity (abdominal with-drawal reflex and abdominal electrical activity) was significantly enhanced in two model groups than two control groups (F = 6.318, 3.978, 7.810, all P < 0.05; F = 6.318, 3.978, 7.810, all P < 0.05). There were no signs of obvious inflammation in the rats of each group.

CONCLUSION: A rat model of IBS induced by intracolonic instillation of acetic acid and restraint stress and Williams method is in accord with visceral hypersensitivity of IBS, feasible for experimental study.