Gastrointestinal motility disorders in patients with inactive Crohn's disease

Smooth muscle dysfunction in the pre-inflammation site in stenotic Crohn's-like colitis: implication of mechanical stress in bowel dysfunction in gut inflammation

Background and Aims: Gut smooth muscle dysfunctions contribute to symptoms such as abdominal cramping, diarrhea, and constipation in inflammatory bowel disease (IBD). The mechanisms for muscle dysfunctions are incompletely understood. We tested the hypothesis that mechanical stress plays a role in muscle dysfunction in a rat model of Crohn's-like colitis where inflammatory stenosis leads to mechanical distention in the pre-inflammation site. Methods: Crohn's-like colitis was induced by intracolonic instillation of TNBS (65 mg/kg) in Sprague-Dawley rats. Control rats were instilled with saline. The rats were fed with either regular solid food or exclusively liquid diet. Rats were euthanized by day 7. Results: When rats were fed with solid food, TNBS treatment induced localized transmural inflammation with stenosis in the instillation site and marked distention with no inflammation in the pre-inflammation site of the colon. Smooth muscle contractility was suppressed, and expression of cyclo-oxygenase-2 (COX-2) and production of prostaglandin E2 (PGE2) were increased not only in the inflammation site but also in the pre-inflammation site. Liquid diet treatment, mimicking exclusive enteral nutrition, completely released mechanical distention, eliminated COX-2 expression and PGE2 production, and improved smooth muscle contractility especially in the pre-inflammation site. When rats were administered with COX-2 inhibitor NS-398 (5 mg/kg, i. p. daily), smooth muscle contractility was restored in the pre-inflammation site and significantly improved in the inflammation site. Conclusion: Colonic smooth muscle contractility is significantly impaired in stenotic Crohn's-like colitis rats not only in the inflammation site, but in the distended pre-inflammation site. Mechanical stress-induced expression of COX-2 plays a critical role in smooth muscle dysfunction in the pre-inflammation site in Crohn's-like colitis rats.

Oxaliplatin-Induced Damage to the Gastric Innervation: Role in Nausea and Vomiting

Nausea and vomiting are common gastrointestinal side effects of oxaliplatin chemotherapy used for the treatment of colorectal cancer. However, the mechanism underlying oxaliplatin-induced nausea and vomiting is unknown. The stomach is involved in the emetic reflex but no study investigated the effects of oxaliplatin treatment on the stomach. In this study, the in vivo effects of oxaliplatin treatment on eating behaviour, stomach content, intrinsic gastric neuronal population, extrinsic innervation to the stomach, levels of mucosal serotonin (5-hydroxytryptamine, 5-HT), and parasympathetic vagal efferent nerve activity were analysed. Chronic systemic oxaliplatin treatment in mice resulted in pica, indicated by increased kaolin consumption and a reduction in body weight. Oxaliplatin treatment significantly increased the stomach weight and content. The total number of myenteric and nitric oxide synthase-immunoreactive neurons as well as the density of sympathetic, parasympathetic, and sensory fibres in the stomach were decreased significantly with oxaliplatin treatment. Oxaliplatin treatment significantly increased the levels in mucosal 5-HT and the number of enterochromaffin-like cells. Chronic oxaliplatin treatment also caused a significant increase in the vagal efferent nerve activity. The findings of this study indicate that oxaliplatin exposure has adverse effects on multiple components of gastric innervation, which could be responsible for pica and gastric dysmotility.

Endoscopic Treatment of Postoperative Bleeding, Bezoars, and Foreign Bodies

Altered gastrointestinal anatomy is common in patients with inflammatory bowel disease, particularly in those who underwent bowel surgery. Commonly performed surgeries are bowel resection and anastomosis and strictureplasty for Crohn's disease; and restorative proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis. The area of anastomosis and suture line is at the greatest risk for the development of postoperative bleeding. Altered bowel anatomy, especially the presence of strictures, strictureplasty, or structural or functional pouch outlet obstruction, puts these patients at risk for bezoar formation and foreign body retention, including video endoscopy capsule. This article will focus on postoperative bleeding, bezoar formation, and video capsule retention in patients with inflammatory bowel disease. Endoscopic management of these conditions is useful and is becoming an increasingly popular alternative to surgery.

[Functional Gastrointestinal Disorders in Patients with Inflammatory Bowel Disease]

With emerging more effective drugs, the therapeutic goal of inflammatory bowel disease (IBD) has progressed from clinical remission to mucosal healing. Although the inflammation could be controlled more effectively than before, symptoms such as abdominal pain and bowel habit change is still bothersome to some IBD patients. Recently, these "refractory functional gastrointestinal symptoms" in quiescent IBD patients has been paid more attention. The pathophysiology could be multifactorial with genetics, change in gut motility associated with post inflammatory condition, increased permeability, impaired colorectal function, visceral hypersensitivity and gut microbiota. Because both IBD and functional gastrointestinal disease (FGID) could share similar symptoms and some pathophysiology, it is sometimes challenging to distinguish them exactly. However, to reduce the risk of overtreatment or insufficient control of inflammation, exact diagnosis of functional disease or symptoms in quiescent IBD patients is important. Because there is limited randomized controlled trials or prospective study currently, most of the therapeutic approach in IBD patients are empirical or referred to those of functional gastrointestinal disorders. However, approaches based on pathophysiological mechanisms could give appropriate therapies for both IBD and FGIDs.

Formulation strategies to improve the efficacy of intestinal permeation enhancers. Adv Drug Deliv Rev 2021;177:113925. [PMID: 34418495 DOI: 10.1016/j.addr.2021.113925]

The use of chemical permeation enhancers (PEs) is the most widely tested approach to improve oral absorption of low permeability active agents, as represented by peptides. Several hundred PEs increase intestinal permeability in preclinical bioassays, yet few have progressed to clinical testing and, of those, only incremental increases in oral bioavailability (BA) have been observed. Still, average BA values of ~1% were sufficient for two recent FDA approvals of semaglutide and octreotide oral formulations. PEs are typically screened in static in vitro and ex-vivo models where co-presentation of active agent and PE in high concentrations allows the PE to alter barrier integrity with sufficient contact time to promote flux across the intestinal epithelium. The capacity to maintain high concentrations of co-presented agents at the epithelium is not reached by standard oral dosage forms in the upper GI tract in vivo due to dilution, interference from luminal components, fast intestinal transit, and possible absorption of the PE per se. The PE-based formulations that have been assessed in clinical trials in either immediate-release or enteric-coated solid dosage forms produce low and variable oral BA due to these uncontrollable physiological factors. For PEs to appreciably increase intestinal permeability from oral dosage forms in vivo, strategies must facilitate co-presentation of PE and active agent at the epithelium for a sustained period at the required concentrations. Focusing on peptides as examples of a macromolecule class, we review physiological impediments to optimal luminal presentation, discuss the efficacy of current PE-based oral dosage forms, and suggest strategies that might be used to improve them.

Disorders of the enteric nervous system - a holistic view

The enteric nervous system (ENS) is the largest division of the peripheral nervous system and closely resembles components and functions of the central nervous system. Although the central role of the ENS in congenital enteric neuropathic disorders, including Hirschsprung disease and inflammatory and functional bowel diseases, is well acknowledged, its role in systemic diseases is less understood. Evidence of a disordered ENS has accumulated in neurodegenerative diseases ranging from amyotrophic lateral sclerosis, Alzheimer disease and multiple sclerosis to Parkinson disease as well as neurodevelopmental disorders such as autism. The ENS is a key modulator of gut barrier function and a regulator of enteric homeostasis. A 'leaky gut' represents the gateway for bacterial and toxin translocation that might initiate downstream processes. Data indicate that changes in the gut microbiome acting in concert with the individual genetic background can modify the ENS, central nervous system and the immune system, impair barrier function, and contribute to various disorders such as irritable bowel syndrome, inflammatory bowel disease or neurodegeneration. Here, we summarize the current knowledge on the role of the ENS in gastrointestinal and systemic diseases, highlighting its interaction with various key players involved in shaping the phenotypes. Finally, current flaws and pitfalls related to ENS research in addition to future perspectives are also addressed.

Functional gastrointestinal disorders in inflammatory bowel disease: Time for a paradigm shift?

Recent advances in biological therapies have revolutionalised and redefined treatment targets in inflammatory bowel disease (IBD). There is now a stronger emphasis on achieving the more stringent therapeutic goals of mucosal and histological healing, rather than clinical remission alone. Consequently, the treatment of refractory “functional” gastrointestinal symptoms, often attributed as the aftermath of previous inflammation, has recently become more prominent in quiescent disease. With further expected advances in anti-inflammatory treatments on the horizon, the burden of such symptoms in quiescent disease, which have been relatively neglected, is set to become an even bigger problem. In this article, we highlight the current state of research and understanding in this field, including recent developments and clinical practice guidelines on the diagnosis and management of functional gastrointestinal symptoms, such as irritable bowel syndrome and functional anorectal and pelvic floor disorders, in patients with quiescent IBD. These disorders are not only highly prevalent in these patients, they are often misdiagnosed, and are difficult to treat, with very few evidence-based therapies. Moreover, they are associated with substantial impairment in quality-of-life, considerable morbidity, and psychological distress. There is therefore an urgent need for a change in emphasis towards earlier recognition, positive diagnosis, and targeted treatment for patients with ongoing functional gastrointestinal symptoms in the absence of active IBD. This article also highlights the need for further research to develop much needed evidence-based therapies.

Site-specific targeted drug delivery systems for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) includes Crohn's disease and ulcerative colitis and manifests as a complex and dysregulated immune response. To date, there is no cure for IBD; thus, lifelong administration of maintenance drugs is often necessary. Since conventional IBD treatment strategies do not target the sites of inflammation, only limited efficacy is observed with their use. Moreover, the possibility of severe side effects resulting from systemic drug redistribution is high when conventional drug treatments are used. Therefore, a straightforward disease-targeted drug delivery system is desirable. Based on the pathophysiological changes associated with IBD, novel site-specific targeted drug delivery strategies that deliver drugs directly to the inflammation sites can enhance drug accumulation and decrease side effects. This review summarizes novel inflammation targeted delivery systems in the management of IBD. It also discusses the challenges and new perspectives in this field.

Abnormal gut motility in inflammatory bowel disease: an update

BACKGROUND

There is substantial evidence linking disturbed gastrointestinal motility to inflammation. Thus, it is not surprising that abnormalities of gastrointestinal motility play a role in inflammatory bowel disease (IBD), affecting patient outcomes. We performed a review of the literature to investigate the relationship between abnormal gut motility and IBD.

METHODS

With an extensive literature search, we retrieved the pertinent articles linking disturbed gut motility to IBD in various anatomical districts.

RESULTS

The evidence in the literature suggests that abnormal gastrointestinal motility plays a role in the clinical setting of IBD and may confuse the clinical picture.

CONCLUSIONS

Abnormal gut motility may be important in the clinical setting of IBD. However, additional data obtained with modern techniques (e.g., magnetic resonance imaging) are needed to individuate in a more precise manner gastrointestinal motor dysfunctions, to understand the nature of clinical manifestations and properly tailor the treatment of patients.

Changes in colonic contractility in response to inflammatory bowel disease: Long-term assessment in a model of TNBS-induced inflammation in rats

AIMS

Inflammatory bowel disease is a chronic relapsing inflammation that affects the gastrointestinal tract, causing changes in colonic motility. The evolution of these changes is not completely understood and possibly related to symptoms that appear in different degrees of the intestinal inflammation. Therefore, our aim is evaluate during 14 days of assessment aspects of colonic contractility using 2,4,6-trinitrobenzenesulfonic acid (TNBS) model of inflammation in rats and associate the inflammatory process with colonic motility.

METHODS

Contractility and inflammatory parameters were assessed in the same animal in six different moments: before intestinal inflammation induction, 2, 5, 8, 11, and 14 days after induction. The mechanical activity was determined by alternating current biosusceptometry (ACB) and subdivided into rhythmic propagating ripples (RPR) and rhythmic propulsive motor complexes (RPMC). We assessed inflammation by determining myeloperoxidase activity in feces.

RESULTS

Transient and permanent changes were observed in colonic motility as a function of the inflammatory process evaluated through myeloperoxidase activity. We identified two contraction profiles: RPR and RPMC. The microscopic analysis demonstrated a depth of damage caused by an injury that was associated with changes in motility.

CONCLUSIONS

We implemented a robust and adequate (specific) signal processing to quantify two measured colonic frequency patterns. Thus, we performed a detailed temporal analysis of the consequences of TNBS-induced inflammation on colonic motility in rats. Our approach enables further long-term assessments in the same animal with different mechanisms and duration of injury, remission, treatments and their motor consequences.

Neuromuscular blockade reversal with sugammadex versus pyridostigmine/glycopyrrolate in laparoscopic cholecystectomy: a randomized trial of effects on postoperative gastrointestinal motility

Background

Acetylcholinesterase inhibitors (e.g., pyridostigmine bromide) are used for neuromuscular blockade (NMB) reversal in patients undergoing surgery under general anesthesia (GA). Concurrent use of anticholinergic agents (e.g., glycopyrrolate) decreases cholinergic side effects but can impede bowel movements. Sugammadex has no cholinergic effects; its use modifies recovery of gastrointestinal (GI) motility following laparoscopic cholecystectomy compared to pyridostigmine/glycopyrrolate. This study evaluated the contribution of sugammadex to the recovery of GI motility compared with pyridostigmine and glycopyrrolate.

Methods

We conducted a prospective study of patients who underwent laparoscopic cholecystectomy. Patients were randomly allocated to the experimental group (sugammadex, Group S) or control group (pyridostigmine-glycopyrrolate, Group P). After anesthesia (propofol and rocuronium, and 2% sevoflurane), recovery was induced by injection of sugammadex or a pyridostigmine-glycopyrrolate mixture. As a primary outcome, patients recorded the time of their first passage of flatus (‘gas-out time’) and defecation. The secondary outcome was stool types.

Results

One-hundred and two patients participated (Group S [n = 49], Group P [n = 53]). Mean time from injection of NMB reversal agents to gas-out time was 15.03 (6.36–20.25) h in Group S and 20.85 (16.34–25.86) h in Group P (P = 0.001). Inter-group differences were significant. Time until the first defecation as well as types of stools was not significantly different.

Conclusions

Sugammadex after laparoscopic cholecystectomy under GA resulted in an earlier first postoperative passage of flatus compared with the use of a mixture of pyridostigmine and glycopyrrolate. These findings suggest that the use of sugammadex has positive effects on the recovery of GI motility.

Hypothesis: Mechanism of irritable bowel syndrome in inflammatory bowel disease

Functional bowel symptoms can be occurred during remission from inflammatory bowel disease. In this case, a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet is effective for the amelioration or prevention of symptoms. However, the reason is not fully explained. This report proposes a hypothesis regarding the entire process in which inflammatory bowel disease with IBS-like symptoms (IBD-IBS) causes symptoms. A detailed process was assumed, starting from high pressure in the lumen and finally to abdominal symptoms. In this process, relationships were linked based on interactions such as ischemia, compliance, pain threshold, visceral hypersensitivity, mast cells, and permeability reported in IBD-IBS. In the process mapping, to understand the relationship between the amount of gas increased by FODMAP and ischemia, the hydrodynamic hypothesis and Ritchie's hypothesis were adapted. Ischemia in dilated intestines due to an increase in gas volume can induce excessive spasms via the mast cells and show the whole process of lowering the pain threshold. From the standpoint of the mechanism of IBD-IBS, the origin trigger may be FODMAP. Therefore, a low-FODMAP diet is recommended to relieve and prevent IBD-IBS symptoms.

Identification of Specific Oral and Gut Pathogens in Full Thickness Colon of Colitis Patients: Implications for Colon Motility

Impaired colon motility is one of the leading problems associated with inflammatory bowel disease (IBD). An expanding body of evidence supports the role of microbiome in normal gut function and in progression of IBD. The objective of this work is to determine whether diseased full thickness colon specimens, including the neuromuscular region (critical for colon motility function), contain specific oral and gut pathogens. In addition, we compared the differences in colon microbiome between Caucasians (CA) and African Americans (AA). Thirty-nine human full thickness colon (diseased colon and adjacent healthy colon) specimens were collected from Crohn's Colitis (CC) or Ulcerative Colitis (UC) patients while they underwent elective colon surgeries. We isolated and analyzed bacterial ribosomal RNA (rRNA) from colon specimens by amplicon sequencing of the 16S rRNA gene region. The microbiome proportions were quantified into Operational Taxonomic Units (OTUs) by analysis with Quantitative Insights Into Microbial ecology (QIIME) platform. Two hundred twenty-eight different bacterial species were identified by QIIME analysis. However, we could only decipher the species name of fifty-three bacteria. Our results show that proportion of non-detrimental bacteria in CC or UC colon samples were altered compared to adjacent healthy colon specimens. We further show, for the first time in full thickness colon specimens, that microbiome of CC and UC diseased specimens is dominated by putative oral pathogens belonging to the Phyla Firmicutes (Streptococcus, Staphylococcus, Peptostreptococcus), and Fusobacteria (Fusobacterium). In addition, we have identified patterns of differences in microbiome levels between CA and AA specimens with potential implications for health disparities research. Overall, our results suggest a significant association between oral and gut microbes in the modulation of colon motility in colitis patients.

Current perspectives on the diagnosis and management of functional anorectal disorders in patients with inflammatory bowel disease

Despite advances in inflammatory bowel disease (IBD) therapies, a significant proportion of patients with quiescent disease experience persistent, debilitating symptoms of faecal incontinence (FI), urgency and defaecatory disorders due to anorectal dysfunction. Such symptoms are often underreported or misdiagnosed and can lead to potentially premature treatment 'escalation' and under-utilisation of pelvic floor investigations. In this review article, we consider putative pathophysiological post-inflammatory changes resulting in altered anorectal sensitivity, motility and neuromuscular coordination and how this may drive symptoms in quiescent IBD. Finally, we discuss a pragmatic approach to investigating and managing anorectal dysfunction and highlight areas for future research for this often-neglected group of patients.

Angiotensin II type II receptors and colonic dysmotility in 2,4-dinitrofluorobenzenesulfonic acid-induced colitis in rats

BACKGROUND

Angiotensin II (Ang II), the main peptide of the renin-angiotensin system (RAS), has been suggested to be involved in inflammatory bowel diseases. Since RAS has emerged as gut motility regulator, and dysmotility is associated with intestinal inflammation, our objective was to investigate in rat 2,4-dinitrobenzenesulfonic acid (DNBS)-induced colitis the functionality of RAS and its contribution to colonic motor alterations.

METHODS

The effects of Ang II on the longitudinal colonic muscular contractility of control and DNBS-treated rats were characterized in vitro. Transcripts encoding for Ang II receptors were investigated by RT-PCR.

KEY RESULTS

Inflamed preparations showed a longitudinal muscle marked hypocontractility. Angiotensin II caused contractile effects in both preparations, but the responses in DNBS preparations were reduced compared to controls. In both preparations, Losartan, AT₁ receptor antagonist, reduced Ang II effects. PD123319, AT₂ receptor antagonist, enhanced Ang II responses only in DNBS rats, as well as N^ω -Nitro-L-arginine (L-NNA), nitric oxide (NO) synthase inhibitor, or tetrodotoxin (TTX), neural toxin. The co-administration of PD123319 and TTX or L-NNA produced no additive effects. PD123319 per se improved colonic contractility in inflamed tissues. The effect was reduced in the presence of L-NNA or TTX. All Ang II receptor subtypes were expressed in both preparations.

CONCLUSIONS & INFERENCES

AT₁ receptors mediate Ang II contractile responses in rat colon. During inflammation a recruitment of Ang II AT₂ receptors would counteract AT₁ -contractile activity. A tonic activation of AT₂ receptors would contribute to the general reduction in muscle contractility during experimental inflammation. A role for enteric neurons and NO is also suggested.

Relationship between use of selective serotonin reuptake inhibitors and irritable bowel syndrome: A population-based cohort study

AIM

To investigate the relationship between selective serotonin reuptake inhibitor (SSRI) use and the subsequent development of irritable bowel syndrome (IBS).

METHODS

This retrospective, observational, population-based cohort study collected data from Taiwan's National Health Insurance Research Database. A total of 19653 patients newly using SSRIs and 78612 patients not using SSRIs, matched by age and sex at a ratio of 1:4, were enrolled in the study from January 1, 2000 to December 31, 2010. The patients were followed until IBS diagnosis, withdrawal from the National Health Insurance system, or the end of 2011. We analyzed the effects of SSRIs on the risk of subsequent IBS using Cox proportional hazards regression models.

RESULTS

A total of 236 patients in the SSRI cohort (incidence, 2.17/1000 person-years) and 478 patients in the comparison cohort (incidence, 1.04/1000 person-years) received a new diagnosis of IBS. The mean follow-up period from SSRI exposure to IBS diagnosis was 2.05 years. The incidence of IBS increased with advancing age. Patients with anxiety disorders had a significantly increased adjusted hazard ratio (aHR) of IBS (aHR = 1.33, 95%CI: 1.11-1.59, P = 0.002). After adjusting for sex, age, urbanization, family income, area of residence, occupation, the use of anti-psychotics and other comorbidities, the overall aHR in the SSRI cohort compared with that in the comparison cohort was 1.74 (95%CI: 1.44-2.10; P < 0.001). The cumulative incidence of IBS was higher in the SSRI cohort than in the non-SSRI cohort (log-rank test, P < 0.001).

CONCLUSION

SSRI users show an increased risk of subsequent diagnosis of IBS in Taiwan.

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.

Alterations of colonic function in the Winnie mouse model of spontaneous chronic colitis

The Winnie mouse, carrying a missense mutation in Muc2, is a model for chronic intestinal inflammation demonstrating symptoms closely resembling inflammatory bowel disease (IBD). Alterations to the immune environment, morphological structure, and innervation of Winnie mouse colon have been identified; however, analyses of intestinal transit and colonic functions have not been conducted. In this study, we investigated in vivo intestinal transit in radiographic studies and in vitro motility of the isolated colon in organ bath experiments. We compared neuromuscular transmission using conventional intracellular recording between distal colon of Winnie and C57BL/6 mice and smooth muscle contractions using force displacement transducers. Chronic inflammation in Winnie mice was confirmed by detection of lipocalin-2 in fecal samples over 4 wk and gross morphological damage to the colon. Colonic transit was faster in Winnie mice. Motility was altered including decreased frequency and increased speed of colonic migrating motor complexes and increased occurrence of short and fragmented contractions. The mechanisms underlying colon dysfunctions in Winnie mice included inhibition of excitatory and fast inhibitory junction potentials, diminished smooth muscle responses to cholinergic and nitrergic stimulation, and increased number of α-smooth muscle actin-immunoreactive cells. We conclude that diminished excitatory responses occur both prejunctionally and postjunctionally and reduced inhibitory purinergic responses are potentially a prejunctional event, while diminished nitrergic inhibitory responses are probably due to a postjunction mechanism in the Winnie mouse colon. Many of these changes are similar to disturbed motor functions in IBD patients indicating that the Winnie mouse is a model highly representative of human IBD.

NEW & NOTEWORTHY

This is the first study to provide analyses of intestinal transit and whole colon motility in an animal model of spontaneous chronic colitis. We found that cholinergic and purinergic neuromuscular transmission, as well as the smooth muscle cell responses to cholinergic and nitrergic stimulation, is altered in the chronically inflamed Winnie mouse colon. The changes to intestinal transit and colonic function we identified in the Winnie mouse are similar to those seen in inflammatory bowel disease patients.

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.

Diagnosis and management of functional symptoms in inflammatory bowel disease in remission

Inflammatory bowel disease (IBD) patients in remission may suffer from gastrointestinal symptoms that resemble irritable bowel syndrome (IBS). Knowledge on this issue has increased considerably in the last decade, and it is our intention to review and summarize it in the present work. We describe a problematic that comprises physiopathological uncertainties, diagnostic difficulties, as IBS-like symptoms are very similar to those produced by an inflammatory flare, and the necessity of appropriate management of these patients, who, although in remission, have impaired quality of life. Ultimately, from almost a philosophical point of view, the presence of IBS-like symptoms in IBD patients in remission supposes a challenge to the traditional functional-organic dichotomy, suggesting the need for a change of paradigm.

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.

Systematic review with meta-analysis: post-infectious functional dyspepsia

BACKGROUND

The prevalence of functional dyspepsia (FD) following infectious gastroenteritis has not been systematically reviewed.

AIM

To conduct a systematic review and calculate the summary odds ratio (OR) for the development of FD following infectious gastroenteritis, as compared to a control population.

METHODS

Published studies in PubMed, EmBASE, and Cochrane Database and abstracts from standard sources were screened for eligible studies. Data from studies meeting inclusion criteria were pooled for meta-analysis.

RESULTS

Nineteen studies were eligible for inclusion. The mean prevalence of FD following acute gastroenteritis (AGE) was 9.55% (FD, n = 909; AGE, n = 9517) in adult populations. The summary OR for the development of post-infectious FD was 2.54 (95% CI = 1.76-3.65) at more than 6 months after AGE, as compared to the prevalence in controls within the same population. This is compared with the summary OR (3.51; 95% CI = 2.05-6.00) for the development of post-infectious irritable bowel syndrome (IBS) in the same population at more than 6 months after AGE. There was significant statistical heterogeneity with an I(2) of 72.8% for the summary OR of post-infectious FD. Several pathogens, including Salmonella spp., Escherichia coli O157, Campylobacter jejuni, Giardia lamblia and Norovirus have been shown to be associated with post-infectious FD symptoms.

CONCLUSIONS

Infectious gastroenteritis is associated with an increased risk for subsequent dyspepsia as well as for irritable bowel syndrome. Post-infectious FD and post-infectious irritable bowel syndrome may represent different aspects of the same pathophysiology. Further studies will be needed to determine this.

Pain management in patients with inflammatory bowel disease: translational approaches from bench to bedside

Abdominal pain is a common symptom in patients with inflammatory bowel disease (IBD) that negatively affects quality of life and can lead to increased health-seeking behavior. Although abdominal pain has been traditionally attributed to inflammation, there is growing literature demonstrating the existence of functional abdominal pain in patients with IBD, of which there are a variety of potential causes. Thus, when approaching a patient with IBD who has abdominal pain, in addition to IBD-related complications (e.g., inflammation/stricture), it is important to screen for related contributors, including peripheral factors (visceral hypersensitivity, bacterial overgrowth, and bowel dysmotility) and centrally mediated neurobiological and psychosocial underpinnings. These central factors include psychological symptoms/diagnoses, sleep disturbance, and stress. Opioid-induced hyperalgesia (e.g., narcotic bowel syndrome) is also growing in recognition as a potential central source of abdominal pain. This review draws from clinical studies and animal models of colitis and abdominal pain to consider how knowledge of these potential etiologies can be used to individualize treatment of abdominal pain in patients with IBD, including consideration of potential novel treatment modalities for the future. Accurate assessment of the source(s) of pain in patients with IBD can help guide appropriate diagnostic workup and use of disease-modifying therapy.

Automated small bowel motility measurements in MRI using 2D coronal slices - does the intrasegmental location matter? A pilot study

INTRODUCTION

To evaluate if small bowel motility analyses are influenced by the positioning of the 2D-cross-section measurement point within the lumen.

MATERIALS AND METHODS

Forty-four small-bowel motility measurements were included in this institutional review board-approved, prospective study. Motility sequences (Dixon-dynFFE; Temporal-resolution 1s, breath-hold) of the ileocecal region were acquired using magnetic resonance imaging (3.0-Tesla; Ingenia-Philips). Motility was analyzed in three different compartments of the small bowel lumen (ventral, central, dorsal). Curve characteristics were statistically compared.

RESULTS

Mean luminal diameter, contraction amplitudes (P>.05) and the extent of luminal occlusion during contraction (P=.11) did not differ significantly between the compartments (ventral/central/dorsal) of the bowel lumen.

CONCLUSION

Quantitative motility parameters are not substantially influenced by the choice of cross sections on coronal planes as long as the segment is visible throughout the measurement.

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.

Implications of the colonic deposition of free hemoglobin-α chain: a previously unknown tissue by-product in inflammatory bowel disease

BACKGROUND

We analyzed inflamed mucosal/submucosal layers of ulcerative colitis (UC = 63) and Crohn's colitis (CC = 50), and unexpectedly, we unveiled a pool of free hemoglobin alpha (Hb-α) chain. Patients with colitides have increased reactive oxidative stress (ROS), DNA oxidation products, free iron in mucosa, in preneoplastic, and in colitis-cancers and increased risks of developing colorectal cancer. All inflammatory bowel disease-related colorectal cancer lesions are found in segments with colitis. Linking this information, we investigated whether free Hb-α is key transformational stepping that increases colitis-related colorectal cancer vulnerability.

METHODS

UC/CC samples were profiled using matrix-assisted laser desorption/ionization mass spectrometry; protein identification was made by liquid chromatography. Diverticulitis was used as control (Ctrl). The presence of Hb(n) (n = α, β, or hemin)/Hb was validated by Western blotting and immunohistochemistry. We tested for DNA damage (DNAD) by exposing normal colonic epithelial cell line, NCM460, to 10 μM and 100 μM of Hb(n)/Hb, individually for 2, 6, and 12 hours. Quantification of Hb-α staining was done by Nikon Elements Advance Research Analysis software. ROS was measured by the production of 8-OHdG. DNAD was assessed by Comet assay. Colonic tissue homogenate antioxidants Nrf2-, CAT-, SOD-, and GPx-expressions were analyzed densitometrically/normalized by β-actin.

RESULTS

Immunohistochemistry of CC/UC mucosal/submucosal compartments stained strongly positive for Hb-α and significantly higher versus Ctrl. NCM460 exposed to Hb(n)/Hb exhibited steadily increasing ROS and subsequent DNAD. DNAD was higher in 10 μM than 100 μM in Hb-β/hemin the first 2 hours then plateaued followed by DNAD repair. This may be likely due to apoptosis in the later concentration. Nrf2 enzyme activities among UC, CC, and ulcerative colitis-associated colon cancer (UCAC) were observed impaired in all inflammatory bowel disease subjects. Decreased levels of Nrf2 among patients with UC versus patients with CC with active disease were insignificant as well as versus Ctrls but significantly lower in UCAC versus Ctrl. SOD was decreased in UC and UCAC and GPx in CC but statistically not significant. Comparing CC versus UC, SOD was significantly lower in CC (P < 0.05). CAT was observed increased among patients with CC/UC/UCAC and GPx in UC and UCAC versus Ctrl, respectively, and significantly increased in CC versus Ctrl (P < 0.01).

CONCLUSIONS

In the colitides, mucosal/submucosal tissue microenvironments demonstrated pool of free Hb-α chain. In vitro exposure of NCM460 cells to Hb(n)/Hb induced ROS and DNAD. Toxic effect of free Hb-α, in colonic epithelial cells, is therefore through production of ROS formation modulated by impairment of antioxidant effects. Targeting reduction-oxidation-sensitive pathways and transcription factors may offer options for inflammatory bowel disease-management and colitis-related cancer prevention.

Correlation between morphological expansion and impairment of intra- and prelesionary motility in inflammatory small bowel lesions in patients with Crohn's disease - preliminary data

INTRODUCTION

The aim of this study is to investigate if alterations of intra- and prelesionary motility in inflamed small-bowel segments correlate with length, wall-thickness and prelesionary dilatation of inflammatory small bowel lesions in patients suffering from Crohn's disease assessed with MRI.

METHODS AND MATERIALS

This retrospective IRB approved study included 25 patients (12 males, 18-77y) with inflammatory lesions examined using (MRE) magnetic resonance imaging enterography. Cine MRE was performed using a coronal 2D steady-state free precession sequence (TR 2.9, TE 1.25) on a 1.5T MRI scanner. Small bowel motility was examined using a dedicated MR-motility assessment software (Motasso, Vers. 1.0, Sohard AG, Bern, Switzerland). Motility patterns (contraction frequency, relative occlusion rate and mean diameter) were assessed in correlation to wall thickness, length and prelesionary dilatation of the lesions. Statistical analysis was performed by calculation of the Pearson's-Correlation coefficient.

RESULTS

The length of the inflammatory segments, the wall thickening and prelesionary dilatation did not correlate with the frequency of the contractions (r=0.17, p=0.477; r=0.316, p=0.123; r=0.161, p=0.441) or the impairment of luminal occlusion (r=0.274, p=0.184; r=0.199, p=.0339; r=0.015, p=0.945) and only the prelesionary dilatation (r=0.410, p=0.042) correlated to the mean luminal diameter of the segment.

CONCLUSION

The degree of motility impairment within inflammatory small bowel lesions does not significantly correlate with the extent of the lesion but with the motility measured in prelesionary, non-affected segments, suggesting an interdependent functional aspect of inflammation even in morphologically non-affected small bowel segments.

Small-bowel dislocation during long-term MRI observation - insights in intestinal physiology

Magnetic resonance imaging (MRI) of the abdomen is a widely established imaging modality in the diagnostic workup of patients suffering from abdominal disorders. Small-bowel motility analyses using MRI have recently been introduced to provide functional information about the intestine not provided by morphological analyses. This is of clinical importance as motility disorders correlate with inflammation. Yet motility analyses mainly rely on a series of acquisitions in coronal orientation. Temporal displacement of small-bowel loops out of the coronal slice could falsify qualitative and quantitative motility analyses. Thus, our study quantified three-dimensional (3D) dislocation of small-bowel loops during abdominal MRI examinations with the patient lying in prone position to investigate its influence on motility analyses. Our study revealed segmental small-bowel displacement during MRI examinations in prone position to predominantly occur in craniocaudal orientation and in a smaller extent in lateral and ventrodorsal orientation. However, the displacement amplitudes are rather small and might not significantly influence small-bowel motility analyses in 2D coronal plane in general.

Dyssynergic defecation: a treatable cause of persistent symptoms when inflammatory bowel disease is in remission

BACKGROUND

Introduction of biologic agents in inflammatory bowel disease (IBD) has increased the likelihood of disease remission. Despite resolution of active inflammation, a subset of IBD patients report persistent defecatory symptoms.

AIM

To evaluate a group of patients with inflammatory bowel disease with suspected functional defecatory disorders, by use of anorectal manometric testing and subsequent biofeedback therapy.

METHODS

A group of IBD patients with persistent defecatory problems despite clinical improvement were included in this study. These patients had no evidence of left-sided disease. Endoscopic and radiographic study findings and timing in relation to the manometry study were recorded. Anorectal manometry was performed by the standard protocol and included rectal sensory assessment, ability to expel a balloon, and pressure dynamics with simulated defecation.

RESULTS

Thirty IBD patients (Crohn's 23 patients; ulcerative colitis six patients) presented with defecatory disorders including constipation (67%) increased stooling (10%), and rectal urgency and/or incontinence and rectal pain (6%). All but one patient had anorectal manometric criteria of dyssynergia (presence of anismus motor pattern and inability to expel the balloon). Of the patients who completed biofeedback therapy, 30% had a clinically significant (≥7-point) improvement in SIBDQ score, with a reduction in health-care utilization after a six-month period (p=0.02).

CONCLUSIONS

Despite remission, some inflammatory bowel disease patients have persistent defecatory symptoms. Defecatory symptoms may not be predictive of an underlying inflammatory disorder. Lack of inflammatory activity and absence of left-sided disease should prompt investigation of functional disorders. Anorectal manometric testing and biofeedback therapy for patients with a diagnosis of dyssynergia may be a useful therapy.

ColoPulse tablets perform comparably in healthy volunteers and Crohn's patients and show no influence of food and time of food intake on bioavailability

ColoPulse tablets are an innovative development in the field of oral drug delivery and are characterized by a colon-specific release. Until now ColoPulse dosage forms (only capsules) have been studied in healthy volunteers having a standardized breakfast three hours after administration but not in specific patient groups and not with a shorter interval between administration and breakfast. Information on bioavailability and release characteristics of ColoPulse tablets in Crohn's patients and the influence of food and time of food intake is a prerequisite to properly design future clinical studies with active substances in these patients. In the current cross-over study bioavailability and drug release characteristics of ColoPulse tablets were compared in healthy volunteers and in Crohn's patients in remission. Furthermore the influence of food and time of food intake on the in vivo drug release behavior of ColoPulse tablets was investigated. In this study the dual label isotope strategy was used which means that a ColoPulse tablet containing (13)C-urea and an uncoated, immediate release tablet containing (15)N2-urea were taken simultaneously. Breath and urine samples were collected during the test day for isotope analysis. The appearance of the stable isotopes in breath and/or urine provides information on the site of release from the dosage form, release characteristics and bioavailability. Both tablets were administered on two different days in a cross-over design: the first day with a breakfast (non-standardized) one hour after administration and the second day with a standardized breakfast three hours after administration of the tablets. There was no difference in instructions for administration between both days. Results of 16 healthy volunteers and 14 Crohn's patients were evaluated. At least 86% (51 out of 59) of all ColoPulse tablets administered in this study released their contents at the desired intestinal region. There was no significant difference in bioavailability between healthy volunteers and Crohn's patients on both days (day 1 75.8% vs 90.2%, p=0.070 and day 2 83.4% vs 91.4%, p=0.265). There was also no significant influence of food and time of food intake on bioavailability in healthy volunteers (75.8% and 83.4%, p=0.077) and in Crohn's patients (90.2% and 91.4%, p=0.618) when day 1 and day 2 were compared. Release characteristics did not significantly differ between healthy volunteers and Crohn's patients. However, food and time of food intake had some, clinically non-relevant, influence on the release characteristics within both groups which is in line with the fact that food affects gastro-intestinal transit times. This study shows that ColoPulse tablets enable the site-specific delivery of drugs or other compounds (e.g. diagnostics) deep in the ileo-colonic region of the intestine of Crohn's patients in a comparable amount and rate as in healthy volunteers. Food and time of food intake had no relevant influence on bioavailability. In conclusion ColoPulse delivery systems are promising and deserve further research for local therapy with immunosuppressive drugs in Crohn's patients in the near future.

Paradoxical regulation of ChAT and nNOS expression in animal models of Crohn's colitis and ulcerative colitis

Morphological and functional changes in the enteric nervous system (ENS) have been reported in inflammatory bowel disease. We examined the effects of inflammation on the expression of choline acetyltransferase (ChAT) and nNOS in the muscularis externae of two models of colonic inflammation, trinitrobenzene sulfonic acid (TNBS)-induced colitis, which models Crohn's disease-like inflammation, and DSS-induced colitis, which models ulcerative Colitis-like inflammation. In TNBS colitis, we observed significant decline in ChAT, nNOS, and protein gene product (PGP) 9.5 protein and mRNA levels. In DSS colitis, ChAT and PGP9.5 were significantly upregulated while nNOS levels did not change. The nNOS dimer-to-monomer ratio decreased significantly in DSS- but not in TNBS-induced colitis. No differences were observed in the percentage of either ChAT (31 vs. 33%)- or nNOS (37 vs. 41%)-immunopositive neurons per ganglia or the mean number of neurons per ganglia (55 ± 5 vs. 59 ± 5, P > 0.05). Incubation of the distal colon muscularis externae in vitro with different types of inflammatory mediators showed that cytokines decreased ChAT and nNOS expression, whereas H₂O₂, a component of oxidative stress, increased their expression. NF-κB inhibitor MG-132 did not prevent the IL-1β-induced decline in either ChAT or nNOS expression. These findings showed that TNBS- and DSS-induced inflammation differentially regulates the expression of two critical proteins expressed in the colonic myenteric neurons. These differences are likely due to the exposure of the myenteric plexus neurons to different combinations of Th1-type inflammatory mediators and H₂O₂ in each model.

Software-assisted small bowel motility analysis using free-breathing MRI: feasibility study

PURPOSE

To validate a software prototype allowing for small bowel motility analysis in free breathing by comparing it to manual measurements.

MATERIALS AND METHODS

In all, 25 patients (15 male, 10 female; mean age 39 years) were included in this Institutional Review Board-approved, retrospective study. Magnetic resonance imaging (MRI) was performed on a 1.5T system after standardized preparation acquiring motility sequences in free breathing over 69-84 seconds. Small bowel motility was analyzed manually and with the software. Functional parameters, measurement time, and reproducibility were compared using the coefficient of variance and paired Student's t-test. Correlation was analyzed using Pearson's correlation coefficient and linear regression.

RESULTS

The 25 segments were analyzed twice both by hand and using the software with automatic breathing correction. All assessed parameters significantly correlated between the methods (P < 0.01), but the scattering of repeated measurements was significantly (P < 0.01) lower using the software (3.90%, standard deviation [SD] ± 5.69) than manual examinations (9.77%, SD ± 11.08). The time needed was significantly less (P < 0.001) with the software (4.52 minutes, SD ± 1.58) compared to manual measurement, lasting 17.48 minutes for manual (SD ± 1.75 minutes).

CONCLUSION

The use of the software proves reliable and faster small bowel motility measurements in free-breathing MRI compared to manual analyses. The new technique allows for analyses of prolonged sequences acquired in free breathing, improving the informative value of the examinations by amplifying the evaluable data.

Mechanisms of motility change on trinitrobenzenesulfonic Acid-induced colonic inflammation in mice

Ulcerative colitis is an inflammatory bowel disease (IBD) characterized by recurrent episodes of colonic inflammation and tissue degeneration in human or animal models. The contractile force generated by the smooth muscle is significantly attenuated, resulting in altered motility leading to diarrhea or constipation in IBD. The aim of this study is to clarify the altered contractility of circular and longitudinal smooth muscle layers in proximal colon of trinitrobenzen sulfonic acid (TNBS)-induced colitis mouse. Colitis was induced by direct injection of TNBS (120 mg/kg, 50% ethanol) in proximal colon of ICR mouse using a 30 G needle anesthetized with ketamin (50 mg/kg), whereas animals in the control group were injected of 50% ethanol alone. In TNBS-induced colitis, the wall of the proximal colon is diffusely thickened with loss of haustration, and showed mucosal and mucular edema with inflammatory infiltration. The colonic inflammation is significantly induced the reduction of colonic contractile activity including spontaneous contractile activity, depolarization-induced contractility, and muscarinic acetylcholine receptor-mediated contractile response in circular muscle layer compared to the longitudinal muscle layer. The inward rectification of currents, especially, important to Ca(2+) and Na(+) influx-induced depolarization and contraction, was markedly reduced in the TNBS-induced colitis compared to the control. The muscarinic acetylcholine-mediated contractile responses were significantly attenuated in the circular and longitudinal smooth muscle strips induced by the reduction of membrane expression of canonical transient receptor potential (TRPC) channel isoforms from the proximal colon of the TNBS-induced colitis mouse than the control.

Dyspeptic symptoms and delayed gastric emptying of solids in patients with inactive Crohn's disease

Background

Patients with Crohn’s disease (CD) have been shown to present dyspeptic symptoms more frequently than the general population. Some of these symptoms could be related to motility disorders to some degree. Then, we propose to investigate whether gastric emptying of solids in patients with inactive CD is delayed and to determine the relationships between gastric emptying and dyspeptic symptoms in inactive CD.

Methods

Twenty-six patients with inactive Crohn’s disease, as defined by a Crohn’s Disease Activity Index (CDAI) < 150, underwent a gastric emptying test by breath test using ¹³C octanoic acid coupled to a solid meal and answered a validated questionnaire (The Porto Alegre Dyspeptic Symptoms Questionnaire) to assess dyspeptic symptoms. Patients with scores ≥ 6 were considered to have dyspepsia. The control group was composed by 19 age- and sex-matched healthy volunteers.

Results

Patients with CD had a significantly longer t 1/2 and t lag (p<0.05) than the controls. CD patients with dyspepsia had significantly (p<0.05) prolonged gastric emptying when compared to patients without dyspeptic symptoms. When the individual symptom patterns were analyzed, only vomiting was significantly associated with delayed gastric emptying (p<0.05). There was no difference between the subgroups of patients with respect to gender, CDAI scores, disease location, clinical behavior (obstructive/obstructive) or previous gastrointestinal surgery.

Conclusion

Delayed gastric emptying in inactive Crohn’s disease patients seems to be associated with dyspeptic symptoms, particularly vomiting, even without any evidence of gastrointestinal obstruction.

Enhanced excitability of guinea pig inferior mesenteric ganglion neurons during and following recovery from chemical colitis

Postganglionic sympathetic neurons in the prevertebral ganglia (PVG) provide ongoing inhibitory tone to the gastrointestinal tract and receive innervation from mechanosensory intestinofugal afferent neurons primarily located in the colon and rectum. This study tests the hypothesis that colitis alters the excitability of PVG neurons. Intracellular recording techniques were used to evaluate changes in the electrical properties of inferior mesenteric ganglion (IMG) neurons in the trinitrobenzene sulfonic acid (TNBS) and acetic acid models of guinea pig colitis. Visceromotor IMG neurons were hyperexcitable 12 and 24 h, but not 6 h, post-TNBS during "acute" inflammation. Hyperexcitability persisted at 6 days post-TNBS during "chronic" inflammation, as well as at 56 days post-TNBS when colitis had resolved. In contrast, there was only a modest decrease in the current required to elicit an action potential at 24 h after acetic acid administration. Vasomotor neurons from inflamed preparations exhibited normal excitability. The excitatory effects of XE-991, a blocker of the channel that contributes to the M-type potassium current, and heteropodatoxin-2, a blocker of the channel that contributes to the A-type potassium current, were unchanged in TNBS-inflamed preparations, suggesting that these currents did not contribute to hyperexcitability. Riluzole, an inhibitor of persistent sodium currents, caused tonic visceromotor neurons to accommodate to sustained current pulses, regardless of the inflammatory state of the preparation, and restored a normal rheobase in neurons from TNBS-inflamed preparations but did not alter the rheobase of control preparations, suggesting that enhanced activity of voltage-gated sodium channels may contribute to colitis-induced hyperexcitability. Collectively, these data indicate that enhanced sympathetic drive as a result of hyperexcitable visceromotor neurons may contribute to small bowel dysfunction during colitis.

Pain management in patients with inflammatory bowel disease: insights for the clinician

Abdominal pain is a common symptom in patients with inflammatory bowel disease (IBD) and has a profound negative impact on patients' lives. There are growing data suggesting that pain is variably related to the degree of active inflammation. Given the multifactorial etiologies underlying the pain, the treatment of abdominal pain in the IBD population is best accomplished by individualized plans. This review covers four clinically relevant categories of abdominal pain in patients with IBD, namely, inflammation, surgical complications, bacterial overgrowth, and neurobiological processes and how pain management can be addressed in each of these cases. The role of genetic factors, psychological factors, and psychosocial stress in pain perception and treatment will also be addressed. Lastly, psychosocial, pharmacological, and procedural pain management techniques will be discussed. An extensive review of the existing literature reveals a paucity of data regarding pain management specific to IBD. In addition, there is growing consensus suggesting a spectrum between IBD and irritable bowel syndrome (IBS) symptoms. Thus, this review for adult and pediatric clinicians also incorporates the literature for the treatment of functional abdominal pain and the clinical consensus from IBD and IBS experts on pharmacological, behavioral, and procedural methods to treat abdominal pain in this population.

Nano- and microparticulate drug carriers for targeting of the inflamed intestinal mucosa

Conventional treatment of inflammatory bowel disease (IBD) is based on the daily administration of high doses of immune-suppressant or anti-inflammatory drugs, often complicated by serious adverse effects. Thus, a carrier system that delivers the drug specifically to the inflamed intestinal regions and shows prolonged drug release would be desirable. The advent of TNF-α antibodies and other biopharmaceuticals as potent and specific immune modulators in recent years has broadened the treatment options in IBD, but further increases the necessity for adequate drug delivery, as integrity and bioactivity of the biological active have to be ensured. Exploiting the pathophysiological idiosyncrasies of IBD such as increased mucus production, changes in the structure of the intestinal epithelium and invasion of activated macrophages, different colloidal drug carrier systems have been designed to passively or actively target the site of inflammation. This review introduces different micro- or nanoparticulate drug delivery systems for oral application in IBD therapy for the delivery of small molecular compounds and next generation therapeutics from the group of biological (i.e. peptide and nucleotide based) drugs.

Cytokine-induced alterations of gastrointestinal motility in gastrointestinal disorders

Inflammation and immune activation in the gut are usually accompanied by alteration of gastrointestinal (GI) motility. In infection, changes in motor function have been linked to host defense by enhancing the expulsion of the infectious agents. In this review, we describe the evidence for inflammation and immune activation in GI infection, inflammatory bowel disease, ileus, achalasia, eosinophilic esophagitis, microscopic colitis, celiac disease, pseudo-obstruction and functional GI disorders. We also describe the possible mechanisms by which inflammation and immune activation in the gut affect GI motility. GI motility disorder is a broad spectrum disturbance of GI physiology. Although several systems including central nerves, enteric nerves, interstitial cells of Cajal and smooth muscles contribute to a coordinated regulation of GI motility, smooth muscle probably plays the most important role. Thus, we focus on the relationship between activation of cytokines induced by adaptive immune response and alteration of GI smooth muscle contractility. Accumulated evidence has shown that Th1 and Th2 cytokines cause hypocontractility and hypercontractility of inflamed intestinal smooth muscle. Th1 cytokines downregulate CPI-17 and L-type Ca²⁺ channels and upregulate regulators of G protein signaling 4, which contributes to hypocontractility of inflamed intestinal smooth muscle. Conversely, Th2 cytokines cause hypercontractilty via signal transducer and activator of transcription 6 or mitogen-activated protein kinase signaling pathways. Th1 and Th2 cytokines have opposing effects on intestinal smooth muscle contraction via 5-hydroxytryptamine signaling. Understanding the immunological basis of altered GI motor function could lead to new therapeutic strategies for GI functional and inflammatory disorders.

Impaired integrity of DNA after recovery from inflammation causes persistent dysfunction of colonic smooth muscle

BACKGROUND & AIMS

Patients with inflammatory bowel disease who are in remission and those who developed irritable bowel syndrome after enteric infection continue to have symptoms of diarrhea or constipation in the absence of overt inflammation, indicating motility dysfunction. We investigated whether oxidative stress during inflammation impairs integrity of the promoter of Cacna1c, which encodes the pore-forming α1C subunit of Ca(v)1.2b calcium channels.

METHODS

We used long-extension polymerase chain reaction to evaluate DNA integrity in tissues from distal colons of rats; trinitrobenzene sulfonic acid was used to induce inflammation.

RESULTS

The H2O2 increased in the muscularis externa 1-7 days after inflammation was induced with trinitrobenzene sulfonic acid. The oxidative stress significantly impaired DNA integrity in 2 specific segments of the Cacna1c promoter: -506 to -260 and -2193 to -1542. The impairment peaked at day 3 and recovered partially by day 7 after induction of inflammation; expression of the products of Cacna1c followed a similar time course. Oxidative stress suppressed the expression of nuclear factor-erythroid-2-related factor 2 (Nrf2), an important regulator of anti-oxidant proteins. Intraperitoneal administration of sulforaphane significantly reversed the suppression of Nrf2, oxidative damage in the promoter of Cacna1c, and suppression of Cacna1c on day 7 of inflammation. The inflammation subsided completely by 56 days after inflammation was induced; however, impairment of DNA integrity, expression of Nrf2 and Cacna1c, and smooth muscle reactivity to acetylcholine remained suppressed at this time point.

CONCLUSIONS

Oxidative stress during inflammation impairs the integrity of the promoter of Cacna1c; impairment persists partially after inflammation has subsided. Reduced transcription of Cacna1c contributes to smooth muscle dysfunction in the absence of inflammation.

Crohn's disease: ultrastructure of interstitial cells in colonic myenteric plexus

The role of the interstitial cells of Cajal (ICC) in chronic inflammatory bowel disease, i.e., ulcerative colitis (UC) and Crohn's disease (CD), remains unclear. Ultrastructural alterations in ICC in the colonic myenteric plexus (ICC-MP) have been reported previously in UC, but descriptions of ICC-MP and other interstitial cells in the myenteric region of the colon are lacking for CD. In the present study, we characterized the ultrastructure of interstitial cells, nerves, and glial cells in the myenteric region in Crohn's colitis (CC). In comparison with controls, varicosities of the myenteric bundles were dilated and appeared to be empty. Lipid droplets and lipofuscin-bodies were prominent in glial cells and neurons. ICC-MP were scanty but, as in controls, had caveolae, prominent intermediate filaments, cytoplasmic dense bodies, and membrane-associated dense bands with a patchy basal lamina. ICC-MP were similar in the various colonic regions. ICC-MP in CC showed no signs of degeneration or cytological changes. As in controls, fibroblast-like cells had abundant coated vesicles but lacked prominent intermediate filaments and caveolae. Macrophages also appeared as in controls. In comparison with ICC-MP in UC, the cytology of ICC-MP in CC were thus undisturbed. The ultrastructural differences between UC and CC might reflect pathophysiological differences of importance for understanding pathogenetic differences between CD and UC.

Differential immune and genetic responses in rat models of Crohn's colitis and ulcerative colitis

Crohn's disease and ulcerative colitis are clinically, immunologically, and morphologically distinct forms of inflammatory bowel disease (IBD). However, smooth muscle function is impaired similarly in both diseases, resulting in diarrhea. We tested the hypothesis that differential cellular, genetic, and immunological mechanisms mediate smooth muscle dysfunction in two animal models believed to represent the two diseases. We used the rat models of trinitrobenzene sulfonic acid (TNBS)- and dextran sodium sulfate (DSS)-induced colonic inflammations, which closely mimic the clinical and morphological features of Crohn's disease and ulcerative colitis, respectively. DSS inflammation induced oxidative stress initially in mucosa/submucosa, which then propagated to the muscularis externa to impair smooth muscle function. The muscularis externa showed no increase of cytokines/chemokines. On the other hand, TNBS inflammation almost simultaneously induced oxidative stress, recruited or activated immune cells, and generated cytokines/chemokines in both mucosa/submucosa and muscularis externa. The generation of cytokines/chemokines did not correlate with the recruitment and activation of immune cells. Consequently, the impairment of smooth muscle function in DSS inflammation was primarily due to oxidative stress, whereas that in TNBS inflammation was due to both oxidative stress and proinflammatory cytokines. The impairment of smooth muscle function in DSS inflammation was due to suppression of Gα(q) protein of the excitation-contraction coupling. In TNBS inflammation, it was due to suppression of the α(1C)1b subunit of Ca(v)1.2b channels, CPI-17 and Gα(q). TNBS inflammation increased IGF-1 and TGF-β time dependently in the muscularis externa. IGF-1 induced smooth muscle hyperplasia; both IGF-1 and TGF-β induced hypertrophy. In conclusion, both TNBS and DSS induce transmural inflammation, albeit with different types of inflammatory mediators. The recruitment or activation of immune cells does not correlate directly with the intensity of generation of inflammatory mediators. The inflammatory mediators in TNBS and DSS inflammations target different genes to impair smooth muscle function.

Crohn's disease of the colon: ultrastructural changes in submuscular interstitial cells of Cajal

Interstitial cells of Cajal (ICC) at the submuscular border of the human colon (ICC-SMP) are the proposed pacemaker cells of the musculature. In patients with Crohn's disease (CD) of the colon, ICC-SMP showed characteristic cytological changes from controls. The changes comprised secondary lysosomes in connection with lipid droplets and cytoplasmic vacuoles or multiple empty, confluent and often outbulging vacuoles merging with cisterns of granular endoplasmic reticulum and clusters of glycogen granules. These changes were most pronounced in patients with macroscopical mucosal inflammation but were also demonstrable in uninvolved colonic segments. Relationships of ICC to other cells were undisturbed. The changes were selective to ICC-SMP, as glial cells, muscle cells and fibroblast-like cells at the submuscular border showed no cytological alterations compared with controls. Varicosities of the submuscular plexus were often empty and dilated. Fibroblast-like cells selectively encased macrophages and mast cells. The cytological changes in ICC-SMP in CD are thus similar to changes seen in ulcerative colitis and may be of pathophysiological significance with regard to the motility and sensory disturbances seen in patients with CD.

Stress-induced alterations in mast cell numbers and proteinase-activated receptor-2 expression of the colon: role of corticotrophin-releasing factor

This study was performed in order to assess whether acute stress can increase mast cell and enterochromaffin (EC) cell numbers, and proteinase-activated receptor-2 (PAR2) expression in the rat colon. In addition, we aimed to investigate the involvement of corticotrophin-releasing factor in these stress-related alterations. Eighteen adult rats were divided into 3 experimental groups: 1) a saline-pretreated non-stressed group, 2) a saline-pretreated stressed group, and 3) an astressin-pretreated stressed group. The numbers of mast cells, EC cells, and PAR2-positive cells were counted in 6 high power fields. In proximal colonic segments, mast cell numbers of stressed rats tended to be higher than those of non-stressed rats, and their PAR2-positive cell numbers were significantly higher than those of non-stressed rats. In distal colonic segments, mast cell numbers and PAR2-positive cell numbers of stressed rats were significantly higher than those of non-stressed rats. Mast cell and PAR2-positive cell numbers of astressin-pretreated stressed rats were significantly lower than those of saline-pretreated stressed rats. EC cell numbers did not differ among the three experimental groups. Acute stress in rats increases mast cell numbers and mucosal PAR2 expression in the colon. These stress-related alterations seem to be mediated by release of corticotrophin-releasing factor.

Long-term downregulation of protease-activated receptor-2 expression in distal colon in rats following bacillary dysentery

The aim of this study was to determine changes of PAR-2 expression in distal colon and the sensitivity of colonic muscle to SLIGRL-NH2, the PAR-2-activating peptide (PAR-2-AP) following bacillary dysentery. Shigella flexneri was administrated intragastrically in healthy male rats to induce bacillary dysentery. The effect of SLIGRL-NH2 on the motility of colonic muscle strips were examined. The expression of PAR-2 was determined by immunohistochemistry and Western blotting. Intragastric administration of S.flexneri induced acute inflammation at the mucosa of the distal colon at 4-11 days, and the inflammation disappeared 18 days later. PAR-2-AP-induced TTX insensitive relaxation of the colonic muscle strips. This inhibitory effect on colonic circular muscle strips was reduced on days 11-35, but the carbachol-induced contraction did not change. PAR-2 was located at the colon smooth muscles cells and myenteric nerve plexus. The amount of PAR-2 expression in distal colon was down regulated on days 11-35. These data indicated that bacillary dysentery exerted a long-term downregulation on the expression of PAR-2 in distal colon. This might be the reason of the low sensitivity of the colon circular muscle strips to the PAR-2-AP-induced relaxation following intragastric administration of S.flexneri.

Persistent gut motor dysfunction in a murine model of T-cell-induced enteropathy

BACKGROUND

Inflammatory bowel disease (IBD) patients in remission often experience irritable bowel syndrome (IBS)-like symptoms. We investigated the mechanism for intestinal muscle hypercontractility seen in T-cell-induced enteropathy in recovery phase.

METHODS

BALB/c mice were treated with an anti-CD3 antibody (100 microg per mouse) and euthanized at varying days post-treatment to investigate the histological changes, longitudinal smooth muscle cell contraction, cytokines (Th1, Th2 cytokines, TNF-alpha) and serotonin (5-HT)-expressing enterochromaffin cell numbers in the small intestine. The role of 5-HT in anti-CD3 antibody-induced intestinal muscle function in recovery phase was assessed by inhibiting 5-HT synthesis using 4-chloro-DL-phenylalanine (PCPA).

KEY RESULTS

Small intestinal tissue damage was observed from 24 h after the anti-CD3 antibody injection, but had resolved by day 5. Carbachol-induced smooth muscle cell contractility was significantly increased from 4 h after injection, and this muscle hypercontractility was evident in recovery phase (at day 7). Th2 cytokines (IL-4, IL-13) were significantly increased from 4 h to day 7. 5-HT-expressing cells in the intestine were increased from day 1 to day 7. The 5-HT synthesis inhibitor PCPA decreased the anti-CD3 antibody-induced muscle hypercontractility in recovery phase.

CONCLUSIONS & INFERENCES

Intestinal muscle hypercontractility in remission is maintained at the smooth muscle cell level. Th2 cytokines and 5-HT in the small intestine contribute to the maintenance of the altered muscle function in recovery phase.

Mechanisms of gastric emptying disturbances in chronic and acute inflammation of the distal gastrointestinal tract

It is unclear why patients with inflammation of the distal bowel complain of symptoms referable to the upper gastrointestinal tract, specifically to gastric emptying (GE) disturbances. Thus we aimed to determine occurrence and putative pathomechanisms of gastric motor disorders in such patients. Thirteen healthy subjects (CON), 13 patients with Crohn's disease (CD), 10 with ulcerative colitis (UC), and 7 with diverticulitis (DIV) underwent a standardized (13)C-octanoic acid gastric emptying breath test. Plasma glucose, CCK, peptide YY, and glucagon-like peptide-1 (GLP-1) were measured periodically and correlated with GE parameters. Results were given in means +/- SD. Compared with CON, GE half time (T) was prolonged by 50% in CD (115 +/- 55 vs. 182 +/- 95 min, P = 0.037). Six CD, 2 DIV, and 2 UC patients had pathological T (>200 min). Postprandial plasma glucose was increased in all patients but was highest in DIV and correlated with T (r = 0.90, P = 0.006). In CD, mean postprandial CCK levels were increased threefold compared with CON (6.5 +/- 6.7 vs. 2.1 +/- 0.6 pmol/l, P = 0.027) and were correlated with T (r = 0.60, P = 0.041). Compared with CON, GLP-1 levels were increased in UC (25.1 +/- 5.2 vs. 33.5 +/- 13.0 pmol/l, P = 0.046) but markedly decreased in DIV (9.6 +/- 5.2 pmol/l, P < 0.0001). We concluded that a subset of patients with CD, UC, or DIV has delayed GE. GE disturbances are most pronounced in CD and might partly be caused by excessive CCK release. In DIV there might be a pathophysiological link between decreased GLP-1 release, postprandial hyperglycemia, and delayed GE. These explorative data encourage further studies in larger patient groups.

The functional-organic dichotomy: postinfectious irritable bowel syndrome and inflammatory bowel disease-irritable bowel syndrome

Gastroenterologists often encounter situations when the clinical and pathophysiological features that typically distinguish functional from organic disorders overlap. This "blurring of boundaries" can occur with post-infectious irritable bowel syndrome (PI-IBS), a subset of IBS and a newly described entity IBD-IBS. The key associating features include pain and usually diarrheal symptoms that are disproportionate to the observed pathology, microscopic inflammation, and often a co-association with psychological distress. A previous initiating gastrointestinal infection is required for PI-IBS and assumed for IBD-IBS. Using this perspective we discuss the clinical and pathophysiological features of PI-IBS and IBD-IBS and the growing evidence for the overlapping features of these two disorders in terms of alteration of gut flora, immune dysregulation, and role of stress. A unifying model of PI-IBS and IBD-IBS is proposed that may have important clinical and research implications. It obligates us to reframe our understanding of illness and disease from the dualistic biomedical model into a more integrated biopsychosocial (BPS) perspective.