Studies on the mechanism of bowel disturbance in ulcerative colitis

Assessing anorectal function in patients with recurrent ulcerative colitis

PURPOSE

Ulcerative colitis (UC) is an inflammatory bowel disease with an unclear etiology that can lead to irreversible changes in distal colonic function in chronic patients. This study investigated anorectal function in recurrent UC patients and identified influencing factors.

METHODS

This prospective study enrolled 33 recurrent UC patients and 40 newly diagnosed patients from January 2019 to December 2022. Data collection included clinical records, scores, and anorectal function assessments. Regression analyses were used to identify factors impacting anorectal function.

RESULTS

Recurrent UC patients had higher baseline CRP and fecal calprotectin levels, increased anxiety and depression, and more severe fecal incontinence. They also had lower BMIs, serum Hb and albumin (ALB) levels, and Inflammatory Bowel Disease Questionnaire scores than did initial-onset UC patients. Multivariate linear regression analysis revealed that long disease duration (coef. - 0.376, P < 0.001) and high fecal calprotectin level (coef. - 0.656, P < 0.001) independently influenced the initial sensation threshold in recurrent UC patients. Additionally, high fecal calprotectin (coef. - 0.073, P = 0.013) and high Zung Self-Rating Anxiety Scale score (coef. - 0.489, P = 0.001) were identified as two independent determinants of the defecation volume threshold. For the defecation urgency threshold, the independent factors included high disease duration (coef. - 0.358, P = 0.017) and high fecal calprotectin level (coef. - 0.499, P = 0.001). Similarly, the sole independent factor identified for the maximum capacity threshold was high fecal calprotectin (coef. - 0.691, P = 0.001).

CONCLUSION

Recurrent UC patients had increased rectal sensitivity and compromised anorectal function, which significantly impacted quality of life. Proactively managing the disease, reducing UC relapses, and addressing anxiety are effective measures for improving anorectal function in these patients.

The colon targeting efficacies of mesalazine medications and their impacts on the gut microbiome

Successful treatment of ulcerative colitis (UC) is highly dependent on several parameters, including dosing regimen and the ability to deliver drugs to the disease site. In this study two strategies for delivering mesalazine (5-aminosalicylic acid, 5-ASA) to the colon were compared in an advanced in vitro model of the human gastrointestinal (GI) tract, the SHIME® system. Herein, a prodrug strategy employing bacteria-mediated drug release (sulfasalazine, Azulfidine®) was evaluated alongside a formulation strategy that utilised pH and bacteria-mediated release (5-ASA, Octasa® 1600 mg). SHIME® experiments were performed simulating both the GI physiology and colonic microbiota under healthy and inflammatory bowel disease (IBD) conditions, to study the impact of the disease state and ileal pH variability on colonic 5-ASA delivery. In addition, the effects of the products on the colonic microbiome were investigated by monitoring bacterial growth and metabolites. Results demonstrated that both the prodrug and formulation approaches resulted in a similar percentage of 5-ASA recovery under healthy conditions. On the contrary, during experiments simulating the GI physiology and microbiome of IBD patients (the target population) the formulation strategy resulted in a higher proportion of 5-ASA delivery to the colonic region as compared to the prodrug approach (P < 0.0001). Interestingly, the two products had distinct effects on the synthesis of key bacterial metabolites, such as lactate and short chain fatty acids, which varied according to disease state and ileal pH variability. Further, both 5-ASA and sulfasalazine significantly reduced the growth of the faecal microbiota sourced from six healthy humans. The findings support that the approach selected for colonic drug delivery could significantly influence the effectiveness of UC treatment, and highlight that drugs licensed for UC may differentially impact the growth and functioning of the colonic microbiota.

Colitis-Induced Small Intestinal Hypomotility Is Dependent on Enteroendocrine Cell Loss in Mice

BACKGROUND & AIMS

The abdominal discomfort experienced by patients with colitis may be attributable in part to the presence of small intestinal dysmotility, yet mechanisms linking colonic inflammation with small-bowel motility remain largely unexplored. We hypothesize that colitis results in small intestinal hypomotility owing to a loss of enteroendocrine cells (EECs) within the small intestine that can be rescued using serotonergic-modulating agents.

METHODS

Male C57BL/6J mice, as well as mice that overexpress (EECOVER) or lack (EECDEL) NeuroD1+ enteroendocrine cells, were exposed to dextran sulfate sodium (DSS) colitis (2.5% or 5% for 7 days) and small intestinal motility was assessed by 70-kilodalton fluorescein isothiocyanate-dextran fluorescence transit. EEC number and differentiation were evaluated by immunohistochemistry, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining, and quantitative reverse-transcriptase polymerase chain reaction. Mice were treated with the 5-hydroxytryptamine receptor 4 agonist prucalopride (5 mg/kg orally, daily) to restore serotonin signaling.

RESULTS

DSS-induced colitis was associated with a significant small-bowel hypomotility that developed in the absence of significant inflammation in the small intestine and was associated with a significant reduction in EEC density. EEC loss occurred in conjunction with alterations in the expression of key serotonin synthesis and transporter genes, including Tph1, Ddc, and Slc6a4. Importantly, mice overexpressing EECs revealed improved small intestinal motility, whereas mice lacking EECs had worse intestinal motility when exposed to DSS. Finally, treatment of DSS-exposed mice with the 5-hydroxytryptamine receptor 4 agonist prucalopride restored small intestinal motility and attenuated colitis.

CONCLUSIONS

Experimental DSS colitis induces significant small-bowel dysmotility in mice owing to enteroendocrine loss that can be reversed by genetic modulation of EEC or administering serotonin analogs, suggesting novel therapeutic approaches for patients with symptomatic colitis.

Comparison of prebiotic candidates in ulcerative colitis using an in vitro fermentation model

AIMS

This study explored the effect of three different prebiotics, the human milk oligosaccharide 2'-fucosyllactose (2'-FL), an oligofructose-enriched inulin (fructo-oligosaccharide, or FOS), and a galacto-oligosaccaride (GOS) mixture, on the faecal microbiota from patients with ulcerative colitis (UC) using in vitro batch culture fermentation models. Changes in bacterial groups and short-chain fatty acid (SCFA) production were compared.

METHODS AND RESULTS

In vitro pH controlled batch culture fermentation was carried out over 48 h on samples from three healthy controls and three patients with active UC. Four vessels were run, one negative control and one for each of the prebiotic substrates. Bacterial enumeration was carried out using fluorescence in situ hybridization with flow cytometry. SCFA quantification was performed using gas chromatography mass spectrometry. All substrates had a positive effect on the gut microbiota and led to significant increases in total SCFA and propionate concentrations at 48 h. 2'-FL was the only substrate to significantly increase acetate and led to the greatest increase in total SCFA concentration at 48 h. 2'-FL best suppressed Desulfovibrio spp., a pathogen associated with UC.

CONCLUSIONS

2'FL, FOS, and GOS all significantly improved the gut microbiota in this in vitro study and also led to increased SCFA.

Quantified small bowel motility in patients with ulcerative colitis and gastrointestinal symptoms: a pilot study

BACKGROUND

Gastrointestinal (GI) symptoms are common in patients with ulcerative colitis (UC), even when the disease is in remission, possibly due to abnormalities in GI motility. Small bowel motility can be assessed globally and in specific intestinal regions during magnetic resonance enterography (MRE) using a displacement mapping technique.

PURPOSE

To investigate whether small bowel motility in MRE differs between patients with UC and controls, and if altered motility correlates with GI symptoms.

MATERIAL AND METHODS

In 2016-2018, patients who were admitted for MRE, regardless of clinical indication, were consecutively invited to the study. Healthy volunteers were recruited. The participants completed a questionnaire regarding GI symptoms and relevant clinical data were reviewed in the medical records. The dynamic imaging series obtained during MRE were sent for motility mapping and a motility index (MI) was calculated in jejunum, ileum and terminal ileum in all participants.

RESULTS

In total, 224 patients and healthy volunteers were enrolled in the study. Fifteen were diagnosed with UC and 22 were considered healthy controls. In UC, the prevalence of GI symptoms was higher than in controls (P < 0.001), both in remission and in active disease. There was no correlation between GI symptoms and small bowel motility in UC. Jejunal motility was lower in UC than in controls (P = 0.049).

CONCLUSION

Jejunal motility is decreased in UC compared with healthy controls, but there is no relationship between small bowel motility and GI symptoms in UC.

Constipation in ulcerative colitis: pathophysiology and practical management

Clinical experience suggests that there is a cohort of patients with refractory colitis who do have faecal stasis that contributes to symptoms. The underlying physiology is poorly understood, partly because until recently the technology to examine segmental colonic motility has not existed. Patients are given little information on how proximal faecal stasis can complicate colitis. Treatment guidelines are scanty and many patients are offered little apart from laxatives and advice on increasing fibre intake, which often makes symptoms worse. This article aims to review the history, pathology and management, and create impetus for future research on this underappreciated condition.

Inhibition of APE1/Ref-1 Redox Signaling Alleviates Intestinal Dysfunction and Damage to Myenteric Neurons in a Mouse Model of Spontaneous Chronic Colitis

BACKGROUND

Inflammatory bowel disease (IBD) associates with damage to the enteric nervous system (ENS), leading to gastrointestinal (GI) dysfunction. Oxidative stress is important for the pathophysiology of inflammation-induced enteric neuropathy and GI dysfunction. Apurinic/apyrimidinic endonuclease 1/redox factor-1 (APE1/Ref-1) is a dual functioning protein that is an essential regulator of the cellular response to oxidative stress. In this study, we aimed to determine whether an APE1/Ref-1 redox domain inhibitor, APX3330, alleviates inflammation-induced oxidative stress that leads to enteric neuropathy in the Winnie murine model of spontaneous chronic colitis.

METHODS

Winnie mice received APX3330 or vehicle via intraperitoneal injections over 2 weeks and were compared with C57BL/6 controls. In vivo disease activity and GI transit were evaluated. Ex vivo experiments were performed to assess functional parameters of colonic motility, immune cell infiltration, and changes to the ENS.

RESULTS

Targeting APE1/Ref-1 redox activity with APX3330 improved disease severity, reduced immune cell infiltration, restored GI function ,and provided neuroprotective effects to the enteric nervous system. Inhibition of APE1/Ref-1 redox signaling leading to reduced mitochondrial superoxide production, oxidative DNA damage, and translocation of high mobility group box 1 protein (HMGB1) was involved in neuroprotective effects of APX3330 in enteric neurons.

CONCLUSIONS

This study is the first to investigate inhibition of APE1/Ref-1's redox activity via APX3330 in an animal model of chronic intestinal inflammation. Inhibition of the redox function of APE1/Ref-1 is a novel strategy that might lead to a possible application of APX3330 for the treatment of IBD.

Risk for Irritable Bowel Syndrome in Patients with Helicobacter Pylori Infection: A Nationwide Population-Based Study Cohort Study in Taiwan

Background: The association between Helicobacter pylori (H. pylori) infection and the risk of developing irritable bowel syndrome (IBS) has yet to be investigated; thus, we conducted this nationwide cohort study to examine the association in patients from Taiwan. Methods: A total of approximately 2669 individuals with newly diagnosed H. pylori infection and 10,676 age- and sex-matched patients without a diagnosis of H. pylori infection from 2000 to 2013 were identified from Taiwan’s National Health Insurance Research Database. The Kaplan–Meier method was used to determine the cumulative incidence of H. pylori infection in each cohort. Whether the patient underwent H. pylori eradication therapy was also determined. Results: The cumulative incidence of IBS was higher in the H. pylori-infected cohort than in the comparison cohort (log-rank test, p < 0.001). After adjustment for potential confounders, H. pylori infection was associated with a significantly increased risk of IBS (adjusted hazard ratio (aHR) 3.108, p < 0.001). In addition, the H. pylori-infected cohort who did not receive eradication therapy had a higher risk of IBS than the non-H. pylori-infected cohort (adjusted HR 4.16, p < 0.001). The H. pylori-infected cohort who received eradication therapy had a lower risk of IBS than the comparison cohort (adjusted HR 0.464, p = 0.037). Conclusions: Based on a retrospective follow-up, nationwide study in Taiwan, H. pylori infection was associated with an increased risk of IBS; however, aggressive H. pylori infection eradication therapy can also reduce the risk of IBS. Further underlying biological mechanistic research is needed.

A dual pH and microbiota-triggered coating (Phloral™) for fail-safe colonic drug release

Enteric-coated dosage forms are widely used for targeting the ileo-colonic region of the gastrointestinal (GI) tract. However, accurate targeting is challenging due to intra- and inter-individual variability in intestinal paramaters such as fluid pH and transit times, which occasionally lead to enteric coating failure. As such, a unique coating technology (Phloral™), which combines two independent release mechanisms - a pH trigger (Eudragit® S; dissolving at pH 7) and a microbiota-trigger (resistant starch), has been developed, offering a fail-safe approach to colonic targeting. Here, we demonstrate that the inclusion of resistant starch in the coating does not affect the pH mediated drug release mechanism or the robustness of the coating in the upper GI tract. In order to make the resistant starch more digestible by bacterial enzymes, heat treatment of the starch in the presence of butanol was required to allow disruption of the crystalline structure of the starch granules. Under challenging conditions of limited exposure to high pH in the distal small intestine fluid and rapid transit through the colon, often observed in patients with inflammatory bowel disease, particularly in ulcerative colitis, this dual-trigger pH-enzymatic coating offers a revolutionary approach for site specific drug delivery to the large intestine.

Is there an association between Helicobacter pylori infection and irritable bowel syndrome? A meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a prevalent and debilitating gastrointestinal condition. Research has reported persistent, low-grade mucosal inflammation and significant overlaps between patients with IBS and those with dyspepsia, suggesting a possible pathogenic role of Helicobacter pylori (H. pylori) in IBS. This study therefore aimed to provide the first systematic review and meta-analysis on the association between H. pylori infection and IBS.

AIM

To investigate the association between H. pylori infection and IBS.

METHODS

Using the keywords "H. pylori OR Helicobacter OR Helicobacter pylori OR infection" AND "irritable bowel syndrome OR IBS", a preliminary search of PubMed, Medline, Embase, Cochrane Database of Systematic Reviews, Web of Science, Google Scholar and WanFang databases yielded 2924 papers published in English between 1 January 1960 and 1 June 2018. Attempts were also made to search grey literature.

RESULTS

A total of 13 clinical studies were systematically reviewed and nine studies were included in the final meta-analysis. Random-effects meta-analysis found a slight increased likelihood of H. pylori infection in patients with IBS, albeit this was not statistically significant (pooled odds ratio 1.47, 95% confidence interval: 0.90-2.40, P = 0.123). It must also be acknowledged that all of the available studies reported only crude odd ratios. H. pylori eradication therapy also does not appear to improve IBS symptoms. Although publication bias was not observed in the funnel plot, there was a high degree of heterogeneity amongst the studies included in the meta-analysis (I 2 = 87.38%).

CONCLUSION

Overall, current evidence does not support an association between IBS and H. pylori infection. Further rigorous and detailed studies with larger sample sizes and after H. pylori eradication therapy are warranted.

Colonic Transit Disorder Mediated by Downregulation of Interstitial Cells of Cajal/Anoctamin-1 in Dextran Sodium Sulfate-induced Colitis Mice

Background/Aims

Interstitial cells of Cajal (ICC) and their special calcium-activated chloride channel, anoctamin-1 (ANO1) play pivotal roles in regulating colonic transit. This study is designed to investigate the role of ICC and the ANO1 channel in colonic transit disorder in dextran sodium sulfate (DSS)-treated colitis mice.

Methods

Colonic transit experiment, colonic migrating motor complexes (CMMCs), smooth muscle spontaneous contractile experiments, intracellular electrical recordings, western blotting analysis, and quantitative polymerase chain reaction were applied in this study.

Results

The mRNA and protein expressions of c-KIT and ANO1 channels were significantly decreased in the colons of DSS-colitis mice. The colonic artificial fecal-pellet transit experiment in vitro was significantly delayed in DSS-colitis mice. The CMMCs and smooth muscle spontaneous contractions were significantly decreased by 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), an ANO1 channel blocker, and NG-Nitro-L-arginine methyl ester hydrochloride (L-NAME), an inhibitor of nitric oxide synthase activity, in DSS-colitis mice compared with that of control mice. Intracellular electrical recordings showed that the amplitude of NPPB-induced hyperpolarization was more positive in DSS-colitis mice. The electric field stimulation-elicited nitric-dependent slow inhibitory junctional potentials were also more positive in DSS-colitis mice than those of control mice.

Conclusion

The results suggest that colonic transit disorder is mediated via downregulation of the nitric oxide/ICC/ANO1 signalling pathway in DSS-colitis mice.

Protection afforded by methanol extract of Calotropis procera latex in experimental model of colitis is mediated through inhibition of oxidative stress and pro-inflammatory signaling

Calotropis procera, a latex producing plant is known to possess medicinal properties including its beneficial effect in gastrointestinal disorders. The anti-inflammatory effect of its latex in various experimental models is noteworthy and in light of this the present study was carried out with an objective to evaluate its efficacy in ulcerative colitis, an inflammatory condition of the colon. Colitis was induced in rats by acetic acid and the rats were divided into four groups where one group served as experimental control and the other groups were treated with two doses of methanol extract of dried latex of C. procera (MeDL; 50 and 150 mg/kg) and mesalazine (MSZ; 300 mg/kg). The study also included normal control (NC) group for comparison of various parameters related to colon like macroscopic changes, ulcer score, adherent mucus content, weight/length ratio, small intestinal transit, oxidative stress and inflammatory markers, tissue histology and immunoreactivity of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and nuclear factor kappa beta (NFκB) subunit p65. Treatment of colitic rats with MeDL produced a significant reduction in colonic mucosal damage as revealed by macroscopic and microscopic evaluation and normalization of tissue levels of oxidative stress markers and pro-inflammatory mediators. The protection afforded by MeDL was also evident from its restorative effect on tissue histology and expression of COX-2, iNOS and NFκB(p65). This study shows that by targeting oxidative stress and NFκB(p65) mediated pro-inflammatory signaling, the latex of C. procera affords protection in colitis and its effect was comparable to that of mesalazine. This study suggests that latex of C. procera could serve as a promising therapeutic option for treating inflammatory conditions of the colon.

Characterization of ulcerative colitis-associated constipation syndrome (proximal constipation)

BACKGROUND

The syndrome of constipation with other abdominal symptoms ("proximal constipation") in ulcerative colitis (UC) is commonly recognized by practitioners but is poorly described, with no recognized definition and little understanding with regard to prevalence and effect of therapies on disease outcomes. This study aimed to address these issues in a cross-sectional, consecutive series of patients with UC.

METHODS

A working definition of proximal constipation was established. Consecutive patients were recruited, and their disease activity, recent medications, and investigations plus abdominal symptoms were assessed at a study visit. Relevant clinical data were also extracted from medical records.

RESULTS

Of 125 patients with UC, (mean age 47, range 14-84 years, 61 male), 58 (46%) fulfilled the definition of proximal constipation. The main symptoms were reduced stool frequency (69%), hard stools (43%), abdominal pain (40%), excessive flatus (29%), straining (24%), and sensation of incomplete emptying (14%). Proximal constipation was associated with female gender (OR 3.45 [1.45-8.24]), left-sided (OR 2.84 [1.14-7.11]) and concurrently active disease (OR 5.56 [1.96-16.67]), but not age, disease duration or therapy. A total of 88% had an increase in anti-inflammatory therapy, with the use of laxatives or fiber supplements in 63% compared with 1.4% of those without proximal constipation.

CONCLUSIONS

Proximal constipation is common, and its risk increases in active and distal disease, especially in women. Validation of its definition and evaluation of therapeutic strategies are needed. A new term "ulcerative colitis-associated constipation syndrome" is proposed to more accurately depict its nature.

Metformin maintains mucosal integrity in experimental model of colitis by inhibiting oxidative stress and pro-inflammatory signaling

Metformin, an antidiabetic drug, is well known for its multifarious properties and its ability to modulate inflammatory cascade. Ulcerative colitis (UC) is an inflammatory condition of the colon where drugs exhibiting anti-inflammatory property have been shown to induce and maintain remission. The objective of the present study was to evaluate the efficacy of metformin against acetic-acid induced colitis in rat. The study included five groups of rats namely normal control, experimental control, drug treated groups (50 and 500mg/kg of metformin, MET50, MET500 and 300mg/kg of mesalazine, MSZ300). Parameters like small intestinal transit and colonic macroscopic changes, ulcer score, weight/length (W/L) ratio, levels of oxidative stress and inflammatory markers, tissue histology and expression of COX-2, iNOS, NFκB(p65) were evaluated. The results of this study show that treatment with metformin significantly decreased colonic mucosal damage, maintained oxidative homeostasis and normalized intestinal transit and W/L ratio in a dose-dependent manner. The restorative effect of metformin on colonic mucosa was accompanied by a marked reduction in the tissue levels of pro-inflammatory mediators and immunoreactivity of COX-2, iNOS and NFκB(p65). Further, its protective effect was found to be comparable to that of mesalazine. This study shows that metformin targets oxidative stress and down regulates transcription factor NFκB(p65) mediated pro-inflammatory signaling and has a therapeutic potential in treating inflammatory conditions of the colon.

Budesonide Multimatrix Is Efficacious for Mesalamine-refractory, Mild to Moderate Ulcerative Colitis: A Randomised, Placebo-controlled Trial

BACKGROUND AND AIMS

Safety and efficacy of budesonide multimatrix, an oral extended-release second-generation corticosteroid designed for targeted delivery throughout the colon, were examined for induction of remission in patients with mild to moderate ulcerative colitis refractory to baseline mesalamine therapy.

METHODS

A randomised, double-blind, placebo-controlled, multicentre trial evaluated efficacy and safety of budesonide multimatrix for induction of remission [ulcerative colitis disease activity index score ≥ 4 and ≤ 10] in 510 adults randomised to once-daily oral budesonide multimatrix 9 mg or placebo for 8 weeks. Patients continued baseline treatment with oral mesalamine ≥ 2.4 g/day.

RESULTS

Combined clinical and endoscopic remission at Week 8 was achieved by 13.0% and 7.5% of patients receiving budesonide multimatrix [n = 230] or placebo [n = 228], respectively, in the modified intention-to-treat population [p = 0.049]. Clinical remission [ulcerative colitis disease activity index rectal bleeding and stool frequency subscale scores of 0] was similar in both groups [p = 0.70]. More patients receiving budesonide multimatrix vs placebo achieved endoscopic remission [ulcerative colitis disease activity index mucosal appearance subscale score of 0; 20.0% vs 12.3%; p = 0.02] and histological healing [27.0% vs 17.5%; p = 0.02]. Adverse event rates were similar [budesonide multimatrix, 31.8%; placebo, 27.1%]. Mean morning cortisol concentrations decreased at Weeks 2, 4, and 8 with budesonide multimatrix but remained within the normal range.

CONCLUSION

Budesonide multimatrix was safe and efficacious for inducing clinical and endoscopic remission for mild to moderate ulcerative colitis refractory to oral mesalamine therapy.

Factors Associated with Fecal Incontinence in Women of Childbearing Age with Crohn's Disease

BACKGROUND

Fecal incontinence is common in women with Crohn's disease, but little is known about the impact of childbirth, perianal Crohn's disease, and past surgical history on fecal incontinence.

METHODS

Self-administered questionnaires were mailed to consecutive women referred to a tertiary gastroenterology centre with a focus on fecal incontinence and childbirth. These data were cross-referenced with a prospective database of the same patients' own Crohn's disease histories. Fecal incontinence was defined as a Cleveland Clinic Incontinence Score ≥5. Factors associated with fecal incontinence were analyzed.

RESULTS

A total of 173 patients were assessed, including 113 parous women. The prevalence of fecal incontinence was 37.5% (95% CI, 30.7-45.0). The disease duration, a history of anal surgery for fistula, the number of childbirths per woman and Crohn's activity were all independently associated with fecal incontinence in a multivariate analysis model. Specifically, among the group of parous women, fecal incontinence was associated with prior abdominal surgery, prior anal surgery, and Crohn's activity. The mode of delivery was not statistically associated with fecal incontinence.

CONCLUSIONS

Fecal incontinence is a significant complaint in at least one-third of women of childbearing age with Crohn's disease. Patients'disease and treatment histories seem to have a comparable effect to their childbirth history concerning the presence of fecal incontinence. Both physicians and surgeons who are involved in the management of Crohn's disease need to keep this in mind.

Impairment of Small Intestinal Function in Ulcerative Colitis: Role of Enteric Innervation

Small intestinal dysfunction has been described in patients with ulcerative colitis and in experimental animal models of colitis. This is demonstrated by a decrease in fluid, electrolyte, amino acid, fat and carbohydrate absorption as well as by deranged intestinal motility. Histopathological changes in the small intestines in colitis have not been consistently demonstrated, but there is evidence of structural and biochemical alterations as shown by increased intestinal permeability and a decrease in the expression of multiple brush border membrane enzymes such as disaccharidases and aminopetidases, in both humans and experimental animals. The pathophysiology of this dysfunction has not been elucidated, but it is thought to include alterations in neural circuitry such as increased neuronal excitability, neuronal damage and changes of neuropeptidergic innervation and receptors as well as an increase in local production of pro-inflammatory cytokines and alterations in the production of some neurohumoral mediators. In the following, we provide an update on the advancement of clinical and scientific contributions to elucidate the underlying mechanisms of the alteration of the functions of apparently intact small intestinal segments, induced by ulcerative colitis.

Assessment of Small Intestinal Transit Times in Ulcerative Colitis and Crohn's Disease Patients with Different Disease Activity Using Video Capsule Endoscopy

Small intestinal transit times (SITT) influence drug bioavailability. This study aimed to compare SITT in Crohn's disease and ulcerative colitis patients with non-inflammatory bowel disease (IBD) and to determine influence of disease activity on transit times, and in addition, to establish the utility of small bowel video capsule endoscopy (SB-VCE) in investigation of SITT in IBD patients. A retrospective review was performed on consecutive patients who had undergone SB-VCE at a university hospital out-patient clinic. In total, 125 non-IBD patients, 55 Crohn's disease patients, and 23 ulcerative colitis patients were included. SITT were calculated from the first duodenal image to the first cecal image. Disease activity was assessed based on endoscopy results and inflammatory markers (calprotectin, C-reactive protein, erythrocyte sedimentation rate). SITT were longer in ulcerative colitis patients compared to non-IBD patients (median 264 min vs. 216 min, p = 0.010). Patients with active Crohn's disease (n = 33) also displayed prolonged SITT compared to non-IBD patients (median 253 min vs 216 min, p = 0.017) and patients with quiescent Crohn's disease (n = 22) (p = 0.005). SITT can be prolonged in IBD patients depending on disease activity which may alter the drug release profiles and clinical response to colonic drug delivery systems. SB-VCE is a simple, non-invasive tool that can be utilized in pharmacokinetic studies to understand drug bioavailability in different patient groups. Moreover, this variability in transit times needs to be simulated in dissolution testing for in vitro in vivo correlations.

Enteric Neuronal Regulation of Intestinal Inflammation

Recent research has highlighted the importance of the two-way interaction between the nervous and immune systems. This interaction is particularly important in the bowel because of the unique properties of this organ. The lumen of the gut is lined by a very large but remarkably thin surface that separates the body from the enteric microbiome. Immune defenses against microbial invasion are thus well developed and neuroimmune interactions are important in regulating and integrating these defenses. Important concepts in the phylogeny of neuroimmunity, enteric neuronal and glial regulation of immunity, changes that occur in the enteric nervous system during inflammation, the fundamental role of serotonin (5-HT) in enteric neuroimmune mechanisms, and future perspectives are reviewed.

Gastric myoelectrical activity in patients with inflammatory bowel disease

Aim: Inflammatory bowel disease is characterized by the presence of gastrointestinal motility disturbances; however alterations in the gastric myoelectrical activity have not been characterized. In this study we have recorded the gastric myoelectrical activity in patients with ulcerative colitis (UC) and Crohn's disease (CD) during their clinical remission. Materials and Methods: Gastric activity was assessed using electrogastrography (EGG) in patients with UC (n = 60), CD (n = 40) and healthy controls (n = 40). In each case, their response to water load test, as well as the dominant frequency (DF), dominant power (DP) and the power ratio (PR) of the electrical activity were recorded. Results: In healthy controls, the resting DF was 2.57 ± 1.05 cycles per minute (cpm), which decreased after water ingestion (2.34 ± 0.99 cpm; P = 0.001). Compared to healthy controls, patients with UC had low resting DF (bradygastria) (2.57 ± 1.05 vs. 1.86 ± 1.28 cpm; P = 0.01). The change in DF after water ingestion was insignificant in patients with UC and CD. Post-water ingestion, healthy controls exhibited an increase in the DP as compared to the resting state, (7.1 [2.93, 102.56] vs. 15.94 [3.92, 133.41] µV²; P = 0.02). Patients with UC (1.26 [0.14, 9.83] vs. 3.27 [0.61, 42.12] µV²) and CD (2.54 [0.44, 47.06] vs. 15.8 [0.1, 126.68] µV²) also showed a significant increase in the DP post-water ingestion. Conclusions: Patients with ulcerative colitis have altered resting gastric myoelectrical activity during the remission phase of the disease.

Regional gastrointestinal transit times in severe ulcerative colitis

BACKGROUND

Gastrointestinal (GI) dysmotility may present secondary to inflammatory bowel disease. The main aim of this study was to investigate GI motility in ulcerative colitis (UC) patients during severe disease activity.

METHODS

Twenty patients with severe UC were studied with a novel telemetric capsule system (3D-Transit) designed for minimally invasive, ambulatory assessment of total and regional GI transit times. Ten patients were available for follow-up during remission. Data were compared to those of 20 healthy subjects (HS).

KEY RESULTS

Total GI transit time was significantly longer in patients with severe UC (median 44.5 h [range 9.9-102.7 h]) than in HS (median 27.6 h [range 9.6-56.4 h]) (p = 0.032). Additionally, during severe UC, transit time was prolonged through the proximal colon (p = 0.003) and there were strong trends toward longer than normal small intestinal transit time (HS: median 4.9 h [range 3.4-8.3 h] vs severe UC patients: median 5.9 h [range 3.9-11.9 h]; p = 0.053) and colorectal transit times (HS: median 18.2 h [range 1.5-43.7] vs severe UC patients: median 34.9 h [range 0.4-90.9 h]; p = 0.056). Our data further indicate that total GI and colorectal transit times may be prolonged in UC during early remission.

CONCLUSIONS & INFERENCES

Total GI transit times are significantly prolonged during severe UC.

Aberrant Motility in Unaffected Small Bowel is Linked to Inflammatory Burden and Patient Symptoms in Crohn's Disease

BACKGROUND

Inflammation-related enteric dysmotility has been postulated as a cause for abdominal symptoms in Crohn's disease (CD). We investigated the relationship between magnetic resonance imaging-quantified small bowel (SB) motility, inflammatory activity, and patient symptom burden.

METHODS

The Harvey-Bradshaw index (HBI) and fecal calprotectin were prospectively measured in 53 patients with CD (median age, 35; range, 18-78 years) the day before magnetic resonance enterography, which included a dynamic (cine), breath-hold motility sequence, repeated to encompass the whole SB volume. A validated registration-based motility quantitation technique produced motility maps, and regions of interest were drawn to include all morphologically normal SB (i.e., excluding diseased bowel). Global SB motility was correlated with calprotectin, HBI, and symptom components (well-being, pain, and diarrhea). Adjustment for age, sex, smoking, and surgical history was made using multivariate linear regression.

RESULTS

Median calprotectin was 336 (range, 0-1280). Median HBI, motility mean, and motility variance were 3 (range, 0-16), 0.33 (0.18-0.51), and 0.01 (0.0014-0.034), respectively. Motility variance was significantly negatively correlated with calprotectin (rho = -0.33, P = 0.015), total HBI (rho = -0.45, P < 0.001), well-being (rho = -0.4, P = 0.003), pain (rho = -0.27, P = 0.05), and diarrhea (rho = -0.4, P = 0.0025). The associations remained highly significant after adjusting for covariates. There was no association between mean motility and calprotectin or HBI (P > 0.05).

CONCLUSIONS

Reduced motility variance in morphologically normal SB is associated with patient symptoms and fecal calprotectin levels, supporting the hypothesis that inflammation-related enteric dysmotility may explain refractory abdominal symptoms in CD.

Magnetic resonance imaging-quantified small bowel motility is a sensitive marker of response to medical therapy in Crohn's disease

BACKGROUND

Magnetic resonance enterography (MRE) can measure small bowel motility, reduction in which reflects inflammatory burden in Crohn's Disease (CD). However, it is unknown if motility improves with successful treatment.

AIM

To determine if changes in segmental small bowel motility reflect response to anti-TNFα therapy after induction and longer term.

METHODS

A total of 46 patients (median 29 years, 19 females) underwent MRE before anti-TNFα treatment; 35 identified retrospectively underwent repeat MRE after median 55 weeks of treatment and 11 recruited prospectively after median 12 weeks. Therapeutic response was defined by physician global assessment (retrospective group) or a ≥3 point drop in the Harvey-Bradshaw Index (prospective group), C-reactive protein (CRP) and the MaRIA score. Two independent radiologists measured motility using an MRE image-registration algorithm. We compared motility changes in responders and nonresponders using the Mann-Whitney test.

RESULTS

Anti-TNFα responders had significantly greater improvements in motility (median = 73.4% increase from baseline) than nonresponders (median = 25% reduction, P < 0.001). Improved MRI-measured motility was 93.1% sensitive (95%CI: 78.0-98.1%) and 76.5% specific (95% CI: 52.7-90.4%) for anti-TNFα response. Patients with CRP normalisation (<5 mg/L) had significantly greater improvements in motility (median = 73.4% increase) than those with persistently elevated CRP (median = 5.1%, P = 0.035). Individuals with post-treatment MaRIA scores of <11 had greater motility improvements (median = 94.7% increase) than those with post-treatment MaRIA score >11 (median 15.2% increase, P = 0.017).

CONCLUSIONS

Improved MRI-measured small bowel motility accurately detects response to anti-TNFα therapy for Crohn's disease, even as early as 12 weeks. Motility MRI may permit early identification of nonresponse to anti-TNFα agents, allowing personalised treatment.

Budesonide foam induces remission in patients with mild to moderate ulcerative proctitis and ulcerative proctosigmoiditis

BACKGROUND & AIMS

Budesonide is a high-potency, second-generation corticosteroid designed to minimize systemic adverse consequences of conventional corticosteroids. We performed 2 randomized, phase 3 trials to evaluate the ability of budesonide rectal foam, formulated to optimize retention and provide uniform delivery of budesonide to the rectum and distal colon, to induce remission in patients with ulcerative proctitis or ulcerative proctosigmoiditis.

METHODS

Two identically designed, randomized, double-blind, placebo-controlled trials evaluated the efficacy of budesonide foam for induction of remission in 546 patients with mild to moderate ulcerative proctitis or ulcerative proctosigmoiditis who received budesonide foam 2 mg/25 mL twice daily for 2 weeks, then once daily for 4 weeks, or placebo.

RESULTS

Remission at week 6 occurred significantly more frequently among patients receiving budesonide foam than placebo (Study 1: 38.3% vs 25.8%; P = .0324; Study 2: 44.0% vs 22.4%; P < .0001). A significantly greater percentage of patients receiving budesonide foam vs placebo achieved rectal bleeding resolution (Study 1: 46.6% vs 28.0%; P = .0022; Study 2: 50.0% vs 28.6%; P = .0002) and endoscopic improvement (Study 1: 55.6% vs 43.2%; P = .0486; Study 2: 56.0% vs 36.7%; P = .0013) at week 6. Most adverse events occurred at similar frequencies between groups, although events related to changes in cortisol values were reported more frequently with budesonide foam. There were no cases of clinically symptomatic adrenal insufficiency.

CONCLUSIONS

Budesonide rectal foam was well tolerated and more efficacious than placebo in inducing remission in patients with mild to moderate ulcerative proctitis and ulcerative proctosigmoiditis. ClinicalTrials.gov ID: NCT01008410 and NCT01008423.

Colitis-induced neuroplasticity disrupts motility in the inflamed and post-inflamed colon

Effective colonic motility involves an intricate pattern of excitatory and inhibitory neuromuscular signals that arise from the enteric neural circuitry of the colon. Recent investigations have demonstrated that inflammation leads to a variety of changes in the physiological properties of the neurons in this circuitry, including hyperexcitability of neurons at the afferent end of the peristaltic reflex, synaptic facilitation, and attenuated inhibitory neuromuscular transmission. Furthermore, links have been established between these changes and disrupted motor activity in the colon, and we now know that some of these changes persist long after recovery from inflammation. It is highly likely that inflammation-induced neuroplasticity, which is not detectable by clinical diagnostics, contributes to disrupted motility in active and quiescent inflammatory bowel disease and in functional gastrointestinal disorders.

Crosstalk at the mucosal border: importance of the gut microenvironment in IBS

The aetiology and pathology of IBS, a functional bowel disorder thought to lack an organic cause, is largely unknown. However, studies suggest that various features, such as altered composition of the gut microbiota, together with increased intestinal permeability, a changed balance in the enteroendocrine system and a dysregulated immune system in the gut, most likely have an important role in IBS. Exactly how these entities act together and give rise to symptoms is still unknown, but an altered gut microbiota composition could lead to dysregulation of the intestinal barrier as well as the enteroendocrine and the immune systems, which (through interactions with the nervous system) might generate symptoms. This Review highlights the crosstalk between the gut microbiota, the enteroendocrine system, the immune system and the role of intestinal permeability in patients with IBS.

Fibrosis in ulcerative colitis: mechanisms, features, and consequences of a neglected problem

Chronic intestinal inflammation and impaired tissue repair leading to intestinal fibrosis are a commonly observed complication in inflammatory bowel disease. This is particularly true for small bowel Crohn's disease. However, the development of fibrosis in ulcerative colitis has remained largely unexplored. This is surprising, given knowledge about its prevalence for decades, well described histopathologic features of fibrotic and stricturing ulcerative colitis, the relevance of the extracellular matrix for intestinal inflammation and fibrosis, and the clinical impact of fibrosis on stricture formation, motility, and the necessary discrimination from colonic malignancy. This systematic review summarizes the current knowledge of ulcerative colitis-related fibrosis, including epidemiology, basic mechanisms, histopathology, and clinical implications.

Neuroplasticity and dysfunction after gastrointestinal inflammation

The gastrointestinal tract is innervated by several distinct populations of neurons, whose cell bodies either reside within (intrinsic) or outside (extrinsic) the gastrointestinal wall. Normally, most individuals are unaware of the continuous, complicated functions of these neurons. However, for patients with gastrointestinal disorders, such as IBD and IBS, altered gastrointestinal motility, discomfort and pain are common, debilitating symptoms. Although bouts of intestinal inflammation underlie the symptoms associated with IBD, increasing preclinical and clinical evidence indicates that infection and inflammation are also key risk factors for the development of other gastrointestinal disorders. Notably, a strong correlation exists between prior exposure to gut infection and symptom occurrence in IBS. This Review discusses the evidence for neuroplasticity (structural, synaptic or intrinsic changes that alter neuronal function) affecting gastrointestinal function. Such changes are evident during inflammation and, in many cases, long after healing of the damaged tissues, when the nervous system fails to reset back to normal. Neuroplasticity within distinct populations of neurons has a fundamental role in the aberrant motility, secretion and sensation associated with common clinical gastrointestinal disorders. To find appropriate therapeutic treatments for these disorders, the extent and time course of neuroplasticity must be fully appreciated.

Glial-derived neurotrophic factor reduces inflammation and improves delayed colonic transit in rat models of dextran sulfate sodium-induced colitis

BACKGROUND

Intestinal inflammation is well known to cause gut dysmotility through the effects on the enteric nervous system. Glial-derived neurotrophic factor (GDNF) has been demonstrated to have anti-inflammatory effects and neuronal protective actions. The aim of this study was to investigate whether the GDNF could improve inflammation-induced gut dysmotility.

METHODS

Recombinant adenoviral vectors encoding GDNF (Ad-GDNF) were administered intracolonically in experimental colitis induced by dextran sulfate sodium (DSS). The disease activity index (DAI) and histological score were measured. Colonic transit was measured by using phenol red and assessed with the geometric center. PGP 9.5 immunostaining was used to examine the number and distribution of enteric neurons. The expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and myeloperoxidase (MPO) activity were measured by ELISA assay. The expression of Akt, caspase-3, bcl-2 and PGP 9.5 was analyzed by western blot assay.

RESULTS

A significant neuronal cell loss and a significant delay in colonic transit accompanied with the neuronal loss following inflammation were observed. GDNF prevented partially the loss of enteric neurons and ameliorated significantly experimental colitis and delayed colonic transit by, at least in part, down-regulation of TNF-α and IL-1β expression, decrease of infiltration of leukocytes, and inhibition of neuronal cell apoptosis.

CONCLUSIONS

GDNF reduces inflammation and improves delayed colonic transit in DSS-induced colitis. GDNF may be a useful therapeutic agent for the treatment of gut dysmotility in patients with UC.

Intestinal microbiota and immune function in the pathogenesis of irritable bowel syndrome

The pathophysiology of irritable bowel syndrome (IBS) is believed to involve alterations in the brain-gut axis; however, the etiological triggers and mechanisms by which these changes lead to symptoms of IBS remain poorly understood. Although IBS is often considered a condition without an identified "organic" etiology, emerging evidence suggests that alterations in the gastrointestinal microbiota and altered immune function may play a role in the pathogenesis of the disorder. These recent data suggest a plausible model in which changes in the intestinal microbiota and activation of the enteric immune system may impinge upon the brain-gut axis, causing the alterations in gastrointestinal function and the clinical symptoms observed in patients with IBS. This review summarizes the current evidence for altered intestinal microbiota and immune function in IBS. It discusses the potential etiological role of these factors, suggests an updated conceptual model for the pathogenesis of the disorder, and identifies areas for future research.

Severity of fecal urgency and incontinence in inflammatory bowel disease: clinical, manometric and sonographic predictors

BACKGROUND

Fecal incontinence (FI) and urgency are prevalent symptoms in patients with inflammatory bowel diseases (IBD). It is unclear which factors determine their severity. We evaluated associations of clinical activity, anorectal motility, and endoanal sonography with FI severity in IBD.

METHODS

Fifty-eight consecutive IBD patients and 14 healthy volunteers participated in a cross-sectional, tertiary-center study. Active disease was defined as Crohn's disease activity index ≥ 150 and as simple clinical colitis index > 2. We assessed anal pressures and fatigue rate index (FRI) of the external anal sphincter (EAS) by manometry, rectal compliance and sensitivity by balloon distension, and sphincter defects by endoanal ultrasound. Significant bivariate associations between these parameters and the fecal incontinence severity scale (FISS) were evaluated in multivariate analysis.

RESULTS

Twenty-seven patients (47%) reported urgency, 13 of which (22%) reported FI. Defects of the internal anal sphincter (IAS) and the EAS were diagnosed in 14 (24%) and 13 patients (22%), respectively. Patients had significantly lower rectal compliance and FRI compared with controls. FISS demonstrated significant bivariate associations with clinical disease activity (P = 0.0115), FRI (P = 0.0018), sonographic IAS and EAS defects (P < 0.0001 and 0.0059), rectal compliance (P = 0.0001), and volume at the threshold of a constant urge (Vurge, P = 0.0002). In multivariate analysis, FISS was associated with clinical disease activity (P = 0.0325), FRI (P = 0.0367), Vurge (P = 0.0091), and sonographic IAS defect(s) (P = 0.0008). The derived model explained 62% of the variance in FISS (P < 0.0001).

CONCLUSIONS

Clinical disease activity and manometric and sonographic anorectal parameters are associated with FI severity in IBD. Prospective studies are warranted to evaluate their predictive value in continence outcomes.

Pharmacokinetics and pharmacodynamics of psychotropic drugs: effect of sex

Data on the specific effects of sex on pharmacokinetics, as well as tolerability, safety, and efficacy of psychotropic medications are still meager, mainly because only recently sex-related issues have attracted a certain degree of interest within the pharmacological domain. Therefore, with the present study, we aimed to provide a comprehensive review of the literature on this topic, through careful MEDLINE and PubMed searches of the years 1990-2012. Generally, data on pharmacokinetics are more consistent and numerous than those on pharmacodynamics. Sex-related differences have been reported for several parameters that influence pharmacokinetics, such as gastric acidity, intestinal motility, body weight and composition, blood volume, liver enzymes (mainly the cytochrome P450), or renal excretion, which may alter plasma drug levels. Sex-related peculiarities may also account for a different sensitivity of men and women to side effects and toxicity of psychotropic drugs. Further, some differences in drug response, mainly to antipsychotics and antidepressants, have been described. Further studies are, however, necessary to explore more thoroughly the impact of sex on the pharmacokinetics and pharmacodynamics of psychotropic drugs, in order to reach the most appropriate and tailored prescription for each patient.

Exploring anorectal manometry as a method to study the effect of locally administered ropivacaine in patients with ulcerative colitis

The symptoms of distal ulcerative colitis have been related to changes in rectal sensitivity and capacity due to inflammation, altered gastrointestinal motility, and sensory perception. With the use of anorectal manometry, the function was measured in seven patients with active distal proctitis during local treatment with ropivacaine. Seven healthy subjects were studied in the same way for comparison with normal conditions. The anal resting pressure and squeezing pressure were similar in all groups. Significantly lower rectal distention volumes were required for rectal sensation, critical volume, and to induce rectal contractility in patients with active disease compared to controls. Rectal compliance was significantly reduced in patients with active and quiescent disease. The increased rectal sensitivity and contractility in patients with active colitis appear to be related to active mucosal inflammation and ulceration. The frequency and urgency of defecation and the fecal incontinence may be due to a hypersensitive, hyperactive, and poorly compliant rectum. The findings in our study indicate that the inflammatory damage to the rectal wall with poor compliance is unaffected by local anaesthetics such as ropivacaine. The symptomatic relief and reduction in clinical symptoms following treatment are not reflected in the anorectal manometric findings.

One-year investigator-blind randomized multicenter trial comparing Asacol 2.4 g once daily with 800 mg three times daily for maintenance of remission in ulcerative colitis

BACKGROUND

Mesalazine (Asacol) is still widely prescribed in divided doses for ulcerative colitis (UC), despite evidence that adherence is improved by once-daily (OD) prescribing. We aimed to investigate whether OD Asacol was as effective as three times (TDS) daily dosing, and to evaluate the role of treatment adherence.

METHODS

An investigator-blind randomized trial was undertaken comparing OD Asacol (three 800 mg tablets) versus one 800 mg TDS in maintenance of remission of UC over 1 year. The primary endpoint was relapse rate, and noninferiority would be concluded if the lower limit of the two-sided 95% confidence interval (CI) of the difference in proportions relapsing (TDS-OD) exceeded -10%. Adherence was measured by tablet counts and self-reported adherence. A subgroup of patients used a bottle cap that recorded all bottle opening events.

RESULTS

In all, 213 patients were randomized. In the intention-to-treat (ITT) population, relapse rates were 31% (95% CI 22%-40%) in the OD and 45% (95% CI 35%-54%) in the TDS group. Primary analysis confirmed the noninferiority of OD dosing. Two of the study populations, ITT and per-protocol (PP), showed potential superiority of OD dosing. All measures of adherence showed that it was significantly better in the OD group. Multivariate analysis, however, showed OD dosing was associated with lower relapse risk independently of adherence.

CONCLUSIONS

OD dosing with Asacol 2.4 g is as safe and effective as TDS dosing, and secondary analysis confirmed significantly reduced relapse rates. The benefit, however, was clinically borderline and may relate in part to ease of adherence.

Diarrhea in chronic inflammatory bowel diseases

Diarrhea is a common clinical feature of inflammatory bowel diseases and may be accompanied by abdominal pain, urgency, and fecal incontinence. The pathophysiology of diarrhea in these diseases is complex, but defective absorption of salt and water by the inflamed bowel is the most important mechanism involved. In addition to inflammation secondary to the disease, diarrhea may arise from a variety of other conditions. It is important to differentiate the pathophysiologic mechanisms involved in the diarrhea in the individual patient to provide the appropriate therapy. This article reviews microscopic colitis, ulcerative colitis, and Crohn's disease, focusing on diarrhea.

Review article: delivery and efficacy of topical 5-aminosalicylic acid (mesalazine) therapy in the treatment of ulcerative colitis

BACKGROUND

The use of topical therapy in the treatment of ulcerative colitis has declined in recent years despite evidence of good efficacy.

AIMS

To review US prescription trends for 5-aminosalicylic acid (5-ASA) since the US approval of Asacol extended-release oral mesalazine (mesalamine) in 1992; to estimate the optimal level of 5-ASA exposure in the distal colon; to determine factors influencing distal colonic exposures; and to compare the effectiveness of different 5-ASA formulations (oral, topical suspension, foam, suppositories) in clinical trials.

METHODS

Review of clinical trials, physiologic studies and prescription trends of various mesalazine formulations for treatment of distal ulcerative colitis.

RESULTS

Between 1992 and 2009, prescriptions for oral mesalazine increased sixfold, whereas topical suspensions declined by 10%. In clinical trials, topical therapy resulted in higher remission and clinical response rates than oral therapy, with trends to earlier improvement. The mucosal concentrations of 5-ASA achieved by topical agents in the distal colon were up to 200-fold higher than those achieved by oral administration alone. Despite active colitis, over 40% of a topically administered 4 g 5-ASA suspension (equal to 1.6 g) reached the sigmoid colon. This likely represents a therapeutic exposure of 5-ASA. Although topical therapies are less convenient than oral medications, treatment algorithms have failed to take into account quality of life improvements resulting from more rapid and complete treatment response.

CONCLUSIONS

Topical mesalazine therapy is superior to oral therapy in distal ulcerative colitis for both therapeutic response and drug delivery. Practice patterns should be re-evaluated in light of this information.

Colitis affects the smooth muscle and neural response to motilin in the rabbit antrum

BACKGROUND AND PURPOSE

The underlying mechanisms of gastric dysfunction during or after an episode of intestinal inflammation are poorly understood. This study investigated the effects of colitis on the contractile effects of motilin, an important endocrine regulator of gastric motility, in the antrum.

EXPERIMENTAL APPROACH

Myeloperoxidase (MPO) activity, NF-kappaB activity and motilin receptor density were determined in the antrum of rabbits 5 days after the induction of 2,4,6-trinitrobenzenesulphonic acid colitis. Smooth muscle and neural responses to motilin were studied in antral smooth muscle strips in vitro.

KEY RESULTS

Colitis did not affect MPO activity, but increased NF-kappaB activity in the antrum. Motilin receptor density in the antrum was not affected. Under control conditions, motilin induced a slowly developing tonic smooth muscle contraction. Five days post-inflammation, tonic contractions to motilin were reduced and preceded by a rapid initial contraction. Other kinases were recruited for the phosphorylation of myosin light chain (MLC) (a multi-functional MLC kinase), and for the inhibition of MLC phosphatase (Rho kinase in addition to protein kinase C) to mediate the motilin-induced contractions during inflammation. Colitis potentiated the cholinergic neural on-contractions in the antrum. This was associated with a hyper-reactivity to motilin and an increased muscle response to ACh.

CONCLUSIONS AND IMPLICATIONS

Colitis altered the course of the motilin-induced smooth muscle contraction in the antrum. This involved changes in the kinases phosphorylating MLC. Increased cholinergic excitability to motilin in the antrum may play a role in the pathogenesis of inflammation-associated gastric motility disorders.

Alterations to enteric neural signaling underlie secretory abnormalities of the ileum in experimental colitis in the guinea pig

Inflammatory bowel diseases (IBD) can involve widespread gastrointestinal dysfunction, even in cases in which inflammation is localized to a single site. The underlying pathophysiology of dysfunction in noninflamed regions is unclear. We examined whether colitis is associated with altered electrogenic ion transport in the ileal mucosa and/or changes in the properties of ileal submucosal neurons. Colitis was induced by administration of trinitrobenzene sulfonic acid (TNBS), and the uninflamed ileum from animals was examined 3, 7, and 28 days later. Electrogenic ion transport was assessed in Ussing chambers. Intracellular microelectrode recordings were used to examine the neurophysiology of the submucosal plexus of the ileum in animals with colitis. Noncholinergic secretion was reduced by 33% in the ileum from animals 7 days after the induction of colitis. The epithelial response to vasoactive intestinal peptide (VIP) was unaltered in animals with colitis, but the response to carbachol was enhanced. Slow excitatory synaptic transmission was dramatically reduced in VIP-expressing, noncholinergic secretomotor neurons. This change was detected as early as 3 days following TNBS treatment. No changes to fast synaptic transmission or the number of VIP neurons were observed. In addition, cholinergic secretomotor neurons fired more action potentials during a given stimulus, and intrinsic primary afferent neurons had broader action potentials in animals with colitis. These findings implicate changes to enteric neural circuits as contributing factors in inflammation-induced secretory dysfunction at sites proximal to a localized inflammatory insult.

Elevated human beta-defensin-2 levels indicate an activation of the innate immune system in patients with irritable bowel syndrome

OBJECTIVES

Irritable bowel syndrome (IBS) is a highly prevalent functional disorder. According to the Rome criteria, macroscopic and histological inflammation is a crucial exclusion criterion for IBS. Human defensins appear to be part of the innate immune system in the gastrointestinal tract. Human beta-defensin-2 (HBD-2) was the first inducible human antimicrobial protein discovered. The expression is induced by probiotic microorganisms and proinflammatory cytokines. Recent results imply that HBD-2 is expressed in active intestinal inflammation, especially in ulcerative colitis (UC). Our aim was to evaluate fecal measurements of HBD-2 in patients with active UC and IBS, and in healthy controls (HCs).

METHODS

Fecal specimens were collected from a total of 100 participants (30 with active UC, 46 IBS, and 24 HCs). Exclusion criteria were the current use of probiotics and antibiotics. Furthermore, IBS patients with elevated C-reactive protein or leukocytes, a history of bacterial overgrowth or infectious gastrointestinal disease over the last 6 month were excluded. Disease status was addressed in all participating subjects by medical history and current symptoms. In addition, each IBS and UC patient underwent ileocolonoscopy with histopathology. Fecal inflammation markers lactoferrin (Lf) and calprotectin (Cal) were measured by enzyme-linked immunosorbent assay (ELISA) and reported as microg/g. Fecal HBD-2 was measured by ELISA and reported as ng/g feces. In addition, immunoblots were performed for fecal HBD-2. Paraffin-embedded tissue from colonic biopsies was tested for HBD-2 peptides by immunohistochemistry.

RESULTS

Lf as well as Cal was elevated in active UC (mean: 152.1+/-s.d. 374.7 microg/g; 103.5+/-87.1 microg/g), compared with IBS (8.3+/-19.4 microg/g; 18.6+/-23.3 microg/g), and HCs (0.4+/-0.5 microg/g; 7.1+/-7.9 microg/g). Scheffe post hoc tests revealed significant differences (P=0.006; P<0.001) between active UC vs. IBS and HC. In contrast, HBD-2 levels were highest in active UC (mean: 106.9+/-s.d. 91.5 ng/g), almost as high in IBS (pts 76.0+/-67.9 ng/g), and lowest for HCs (29.9+/-16.1 ng/g). Scheffe post hoc tests revealed significant differences (P<0.001) between the groups of patients (UC and IBS) vs. HCs. Immunohistochemical investigation was consistent with fecal secretion data and demonstrated the presence of beta-defensin 2 peptides in colonic epithelial enterocytes in UC as well as IBS patients with elevated fecal HBD-2.

CONCLUSIONS

The results indicate significantly elevated levels of HBD-2 in patients with IBS compared with HCs and similar to those with active UC. The results support an activation of the mucosal innate defense system toward a proinflammatory response in IBS patients in the absence of macroscopic signs of inflammation.

Enterochromaffin cell hyperplasia in irritable pouch syndrome

BACKGROUND

Irritable pouch syndrome (IPS) is a functional disease in patients with ileal pouch-anal anastomosis following colectomy for ulcerative colitis (UC). The pathophysiology of IPS is characterized by the presence of visceral hypersensitivity, similar to that seen in irritable bowel syndrome. However, the exact etiology and pathogenesis of IPS are not known. We hypothesized that serotonin-containing enteroendocrine cells or enterochromaffin (EC) cell hyperplasia and alterations in the mucosal immune cells may contribute to the patients' symptoms. The aim of the study was to assess EC cell hyperplasia and alterations in the mucosal immune cells in IPS.

METHODS

The Pouchitis Disease Activity Index (PDAI) was used to quantify symptoms and mucosal inflammation in 36 patients with IPS and 25 patients with normal pouches. The histology and immunohistochemistry of pouch mucosal biopsies were assessed by a blinded gastrointestinal pathologist for intraepithelial lymphocytes (IEL), CD3+ T cells, CD25- (interleukin [IL]-2 receptor), tryptase- (mast cells), and serotonin-expressing cells. The numbers of IEL and immune-stained cells were compared between the two groups.

RESULTS

Both groups were compatible demographically in terms of age, gender, duration of UC, stage, indication, and duration of the pouch surgery. There were no differences in the number of IEL, CD3+ T cells, CD25+ cells, and mast cells between the IPS and normal control groups. However, there were a significantly larger number of EC cells in the IPS group than that in the control group (54.8 +/- 24.9 vs 36.7 +/- 17.5 per 4 200x epithelial cells, P < 0.005). The number of EC cells appeared to be correlated with the symptom score (r = 0.276, P= 0.032). There were no significant correlations between the PDAI endoscopy and histology scores and the number of EC cells or between the PDAI scores and the number of IEL or other immune-stained cells.

CONCLUSIONS

A greater number of EC cells were found in the IPS group than the normal pouch group, and the number of EC cells appeared to be correlated with the clinical symptoms of IPS. EC cell hyperplasia may be a contributing mechanism of visceral hypersensitivity and symptoms in IPS.

Impairment and restoration of spontaneous contractile activity of longitudinal smooth muscles in the TNBS-inflamed hamster distal colon

In the present study, we aimed to determine how inflammation affects spontaneous motility in the longitudinal direction of a hamster colon preparation. Trinitrobenzene sulfonic acid (TNBS) injected into the distal colon caused diarrhea 4-7 days after the treatment, but diarrhea was not observed in hamsters kept for 4 weeks. At 1 week after induction of colitis, spontaneous motility in the longitudinal direction was strongly suppressed. Contraction of longitudinal smooth muscles induced by electrical field stimulation was impaired, but not that induced by exogenously applied acetylcholine, indicating that acute inflammation preferentially impairs neurotransmissions with a minor effect on contractility of the longitudinal smooth muscle itself. The spontaneous motility reappeared in the colonic preparation isolated from the hamster maintained for 4 weeks after induction of colitis. The reappearance of the motility accompanied cholinergic and nitrergic regulations of contractile activity. These results demonstrated that impairment and following restoration of spontaneous contractile activity of longitudinal smooth muscles in the TNBS-inflamed distal colon of the hamster may depend on the damage and recovery of neural factors, rather than alteration of muscle contractility.

Review article: gastrointestinal sensory and motor disturbances in inflammatory bowel disease - clinical relevance and pathophysiological mechanisms

BACKGROUND

It is well known that inflammation has a profound impact on the neuromuscular apparatus of the gastrointestinal tract during the inflammatory insult and in periods of remission, at the site of inflammation and at distance from this site. The importance of this interaction is illustrated by the higher prevalence of functional gut disorders in patients with inflammatory bowel disease.

AIMS

To document the epidemiological and clinical significance of functional alterations of gut motility and sensitivity in patients with inflammatory bowel disease and to formulate potential pathophysiological mechanisms.

RESULTS AND CONCLUSIONS

Functional gut disorders occur frequently in patients with inflammatory bowel disease, both during inflammatory episodes and in periods of remission, and have a major impact on their quality of life. The clinical manifestations of these motility and sensitivity disorders vary and are often difficult to treat, mainly because therapeutic guidelines and specific diagnostic tests to distinguish inflammatory bowel disease from functional gut disorders are lacking. Chronic bowel inflammation results in a complicated interaction between neuroendocrine serotonin-predominant cells of the mucosa, inflammatory cells (particularly mast cells) in the submucosa, the intrinsic and extrinsic innervation and the muscular apparatus including the interstitial cells of Cajal. The outcome of this interaction is a perturbation of gastrointestinal motor function, both locally and at distance from the site of inflammation and during both acute inflammation and remission.

Ileal pouch-anal anastomosis

BACKGROUND

Since 1977, restorative proctocolectomy with ileoanal anastomosis (IAA) has evolved into the surgical treatment of choice for most patients with intractable ulcerative colitis. Construction of an ileal pouch reservoir is now standard, usually in the form of J pouch (IPAA). The aim of this report is to review selection criteria for, and functional outcomes, follow-up and management of complications of IPAA after 30 years of widespread clinical application.

METHODS AND RESULTS

Literature published in English on the clinical indications, surgical technique, morbidity, complications and outcome following IAA and IPAA was sourced by electronic search, performed independently by two reviewers who selected potentially relevant papers based on title and abstract. Additional articles were identified by cross-referencing from papers retrieved in the initial search.

CONCLUSION

The functional results of IPAA are good. Pouchitis, irritable pouch syndrome and cuffitis are specific long-term complications but rarely result in failure. Pouch salvage is possible in selected patients with poor functional outcomes. One-stage operations are increasingly performed.

Time course of neural and contractile disturbances in a rat model of colitis induced by Trichinella spiralis

Colitis induced by Trichinella spiralis in rat induces alterations in the spontaneous motor pattern displayed by circular colonic muscle [Auli, M., Fernandez, E., 2005. Characterization of functional and morphological changes in a rat model of colitis induced by T. spiralis. Digestive Diseases and Sciences 50(8), 1432-1443]. We examined the temporal relationship between the severity of inflammation and the altered contractility of the underlying circular muscle as well as the role of NANC inhibitory pathways in the disruption of the motility pattern. Colitis was induced by intrarectal administration of T. spiralis larvae. Responses to acetylcholine (ACh) and increased extracellular potassium as well as the effect of tetrodotoxin (TTX, 1 microM), N-nitro-l-arginine (L-NOARG, 1 mM) and apamin (1 microM) were determined in vitro in the organ bath with circular muscle strips from sham-infected and infected rats at days 2-30 postinfection (PI). Microelectrode recordings were performed to study the putative changes in electrical activity of colonic smooth muscle cells. Responses to ACh and KCl were decreased at all days PI compared to sham. Intracellular calcium depletion had a greater inhibitory effect in inflamed tissue (6-14 PI). The effect of TTX, L-NOARG and apamin on the spontaneous contractions was found to be altered in all infected rats, i.e. their effects were transient and milder. Inflamed tissue showed lower resting membrane potential and a decreased duration of inhibitory junction potentials induced by electrical stimulation. These data suggest that the decreased contractility of colonic circular smooth muscle induced by the intrarectal T. spiralis infection results from the impairment of the excitation-contraction coupling, from a persistent hyperpolarization of smooth muscle cells and from impaired NANC inhibitory neurotransmission.

Serotonin synthesis and uptake in symptomatic patients with Crohn's disease in remission

BACKGROUND & AIMS

Symptoms resembling irritable bowel syndrome (IBS) are reported frequently in Crohn's disease (CD) patients in remission. Studies of the mucosal content of serotonin, which is a pivotal neurotransmitter in the gut, suggest that serotonin availability is altered in IBS patients. We aimed to study the role of serotonin in the generation of IBS-like symptoms in CD patients in remission.

METHODS

Ileal and colonic biopsy specimens were obtained from 20 CD patients in remission, 10 with and 10 without IBS-like symptoms, and 11 healthy controls. Enterochromaffin cells were counted, and messenger RNA expression levels of tryptophan hydroxylase (TpH)-1 and serotonin reuptake transporter were determined.

RESULTS

The levels of mucosal serotonin reuptake transporter expression were significantly higher in the ileum than in the colon, in all groups studied (P < .02). When the ileum and colon were analyzed separately, TpH-1 expression in the colon of CD patients with IBS-like symptoms was found to be significantly higher compared with the 2 other studied groups (controls, P < .005; CD patients without IBS-like symptoms, P < .01). The number of enterochromaffin cells per gland was comparable for the patient groups in the ileum and colon.

CONCLUSIONS

CD patients in remission who experience IBS-like symptoms have increased mucosal TpH-1 levels in the colon, suggesting that increased serotonin biosynthesis in the colon plays a role in the generation of the symptoms.