Transit through the proximal colon influences stool weight in the irritable bowel syndrome

Exploring β-glucan as a micro-nano system for oral delivery targeted the colon

The critical role of oral colon-specific delivery systems (OCDDS) is important for delivering active agents to the colon and rectum specifically via the oral route. The use of micro/nanostructured OCDDS further improves drug stability, bioavailability, and retention time, leading to enhanced therapeutic effects. However, designing micro/nanoscale OCDDSs is challenging due to pH changes, enzymatic degradation, and systemic absorption and metabolism. Biodegradable natural polysaccharides are a promising solution to these problems, and β-glucan is one of the most promising natural polysaccharides due to its unique structural features, conformational flexibility, and specific processing properties. This review covers the diverse chemical structures of β-glucan, its benefits (biocompatibility, easy modification, and colon-specific degradation), and various β-glucan-based micro/nanosized OCDDSs, as well as their drawbacks. The potential of β-glucan offers exciting new opportunities for colon-specific drug delivery.

Abnormal gastrointestinal motility is a major factor in explaining symptoms and a potential therapeutic target in patients with disorders of gut-brain interaction

The objective of this article is to review the evidence of abnormal gastrointestinal (GI) tract motor functions in the context of disorders of gut-brain interaction (DGBI). These include abnormalities of oesophageal motility, gastric emptying, gastric accommodation, colonic transit, colonic motility, colonic volume and rectal evacuation. For each section regarding GI motor dysfunction, the article describes the preferred methods and the documented motor dysfunctions in DGBI based on those methods. The predominantly non-invasive measurements of gut motility as well as therapeutic interventions directed to abnormalities of motility suggest that such measurements are to be considered in patients with DGBI not responding to first-line approaches to behavioural or empirical dietary or pharmacological treatment.

Clinical efficacy of one-finger meditation massage on IBS-C based on the "gut-brain axis" theory: study protocol for a randomized controlled trial

BACKGROUND

As a common disorder of the gastrointestinal tract, irritable bowel syndrome (IBS) can have negative effects on patients and society, with irritable bowel syndrome with constipation(IBS-C) accounting for a large proportion of these effects. The main clinical manifestations of IBS-C are constipation, abdominal pain, and abdominal distension, which seriously impact the quality of life of patients. The mechanisms of IBS are complex, and the gut-brain axis has been an emerging and recognized theoretical system in recent years. Based on the theory of the gut-brain axis and the theory of Chinese medicine, we designed this study to evaluate the efficacy of one-finger meditation massage in treating IBS-C.

METHODS/DESIGN

This is a randomized controlled trial. Eligible patients with irritable bowel syndrome (IBS-C) wererandomized 1:1 to a test group (massage plus probiotics) and a control group (probiotics). Patients in the test group weretreated once every 10 days for three consecutive courses of treatment (i.e., three months) and weregiven Bifidobacterium trifolium capsules 630 mg/dose three times daily 30 min after meals every day during the treatment period, with follow-up observations at the end of the third and sixth months of the treatment period. The control group weregiven Bifidobacterium trifolium capsules 630 mg/dose, 3 times a day for 3 months, with follow-up observations at the end of the third and sixth months of the treatment period. The primary outcome indicators are the concentrations of 5-HT and substance P and the IBS Severity Scale (IBS-SSS) assessment. Secondary outcomes are the Bristol Rating Scale (BRSA) score, the IBS Quality of Life Questionnaire (IBS-QOL scale) score, and the assessment of the effectiveness of the evidence. The results wereassessed at the pretreatment, posttreatment, and follow-up stages. Any side effects weresubject to assessment.

DISCUSSION

The aim of this trial is to provide a new method of treatment based on pharmacological treatment that is easy to use, easy to promote and has proven efficacy and to establish the efficacy and safety of treating IBS-C through this trial.

REGISTRATION FOR TRIAL

Chinese Clinical Trial Registry ChiCTR2200066417 on 5 December 2022. https://www.chictr.org.cn/bin/project/edit?pid=183461.

Irritable bowel syndrome: treatment based on pathophysiology and biomarkers

OBJECTIVE

To appraise the evidence that pathophysiological mechanisms and individualised treatment directed at those mechanisms provide an alternative approach to the treatment of patients with irritable bowel syndrome (IBS).

DESIGN

A PubMED-based literature review of mechanisms and treatment of IBS was conducted independently by the two authors, and any differences of perspective or interpretation of the literature were resolved following discussion.

RESULTS

The availability of several noninvasive clinical tests can appraise the mechanisms responsible for symptom generation in IBS, including rectal evacuation disorders, abnormal transit, visceral hypersensitivity or hypervigilance, bile acid diarrhoea, sugar intolerances, barrier dysfunction, the microbiome, immune activation and chemicals released by the latter mechanism. The basic molecular mechanisms contributing to these pathophysiologies are increasingly recognised, offering opportunities to intervene with medications directed specifically to food components, receptors and potentially the microbiome. Although the evidence supporting interventions for each mechanism is not at the same level of proof, the current state-of-the-art provides the opportunity to advance the practice from treatment based on symptoms to individualisation of treatment guided by pathophysiology and clinically identified biomarkers.

CONCLUSION

These advances augur well for the implementation of evidence-based individualised treatment for patients with IBS based on actionable biomarkers or psychological disturbances.

Colorectal cancer management: Strategies in drug delivery

INTRODUCTION

Colorectal cancer (CRC) is the third most common cancer leading to death worldwide following breast and lung cancer with the incidence rate of 10%. The treatment comprises of surgery, radiation, and ablation therapy depending upon the stage of cancer.

AREAS COVERED

The review focuses on various drug delivery strategies explored to circumvent the major constraints associated with the conventional drug delivery systems- poor bioavailability, intra- and inter individual variability, exposure of normal cells to antineoplastic agents, and presence of efflux pump. All these attributes impact the effective delivery of chemotherapeutic agents at the tumor site. The various target specific drug delivery systems developed for colorectal cancer include pH dependent, microbiologically triggered, time dependent, magnetically driven, pressure dependent, prodrug/polysaccharide based, osmotic and ligand mediated systems. This review enumerates novel target specific approaches developed and investigated for potential utility in CRC therapeutics.

EXPERT OPINION

The limitations of conventional delivery systems can be overcome by development of colon-specific targeted drug delivery systems that overcome the obstacles of nonspecific biodistribution, drug resistance and unwanted adverse effects of conventional drug delivery systems. In addition, nanotechnology approaches help to increase drug solubility, bioavailability, reduce side effects and provide superior drug response in CRC.

Latest Insights on the Pathogenesis of Irritable Bowel Syndrome

The pathogenesis of irritable bowel syndrome is multifactorial and complex. Our understanding of its pathophysiology has evolved, but remains incompletely understood. Symptoms result from a dysregulation of brain-gut interactions. Evidence has identified alterations in central and peripheral (gut) mechanisms in irritable bowel syndrome and the bidirectional communication between the brain and the gut. Pertinent mechanisms include disturbed gut motility, visceral hypersensitivity, altered mucosal and immune function, altered gut microbiota, and altered central nervous system processing. This review addresses factors that increase the risk of irritable bowel syndrome and the central and peripheral mechanisms thought to underlie its symptoms.

Inulin as a Delivery Vehicle for Targeting Colon-Specific Cancer

Natural polysaccharides, as well as biopolymers, are now days widely developed for targeting colon cancer using various drug delivery systems. Currently, healing conformations are being explored that can efficiently play a multipurpose role. Owing to the capability of extravagance colonic diseases with the least adverse effects, biopolymers for site specific colon delivery have developed an increased curiosity over the past decades. Inulin (INU) was explored for its probable application as an entrapment material concerning its degradation by enzymes in the colonic microflora and its drug release behavior in a sustained and controlled manner. INU is a polysaccharide and it consists of 2 to 1 linkage having an extensive array of beneficial uses such as a carrier for delivery of therapeutic agents as an indicative/investigative utensil or as a dietary fiber with added well-being aids. In the main, limited research, as well as information, is available on the delivery of therapeutic agents using inulin specifically for colon cancer because of its capability to subsist in the stomach's acidic medium. This exceptional steadiness and robustness properties are exploited in numerous patterns to target drugs securely for the management of colonic cancer, where they effectively act and kills colonic tumor cells easily. In this review article, recent efforts and inulin-based nano-technological approaches for colon cancer targeting are presented and discussed.

Sexual dimorphism in maternally separated rats: effects of repeated homotypic stress on gastrointestinal motor functions

Experiencing stressful events during early life has been considered as a risk factor for development of functional gastrointestinal disorders in adulthood. This study aimed to investigate the sex-related differences in stress-induced gastrointestinal (GI) dysmotility in rats exposed to neonatal maternal separation (MS). Newborn pups were removed from mothers for 180 min from postnatal day-1 to day-14. Experiments were performed in male and female offsprings at adulthood. Elevated plus maze (EPM) test was used to assess MS-induced anxiety-like behaviors. Ninety minute of restraint stress was applied for once or 5 consecutive days for acute stress (AS) or repeated homotypic stress (RHS), respectively. Measurement of fecal output (FO) and gastric emptying (GE), and hypothalamic microdialysis were performed. Both in males and females, MS produced anxiety-like behaviors. AS delayed GE and increased FO in all groups. In RHS-loaded MS females, AS-induced alterations in GE and FO were restored, however, no adaptation was observed in male counterparts. Regardless of sex and neonatal stress experience, AS significantly increased corticotropin-releasing factor (CRF) release from paraventricular nucleus of hypothalamus, whereas females were found more susceptible than males. Following RHS, AS-induced elevations in CRF release were attenuated only in MS females, but not in males. Both females and males seem to be prone to AS-induced alterations in hypothalamic CRF system and in GI motor functions. Neonatal MS disturbs chronic stress coping mechanisms in males. Conversely, females are likely to circumvent the deleterious effects of neonatal MS on GI functions through developing a habituation to prolonged stressed conditions.

Targeted Drug Delivery: Trends and Perspectives

BACKGROUND

Due to various limitations in conventional drug delivery system, it is important to focus on the target-specific drug delivery system where we can deliver the drug without any degradation. Among various challenges faced by a formulation scientist, delivering the drug to its right site, in its right dose, is also an important aim. A focused drug transport aims to extend, localize, target and have a safe drug interaction with the diseased tissue.

OBJECTIVE

The aim of targeted drug delivery is to make the required amount of the drug available at its desired site of action. Drug targeting can be accomplished in a number ways that include enzyme mediation, pH-dependent release, use of special vehicles, receptor targeting among other mechanisms. Intelligently designed targeted drug delivery systems also offer the advantages of a low dose of the drug along with reduced side effects which ultimately improves patient compliance. Incidences of dose dumping and dosage form failure are negligible. A focused drug transport aims to have a safe drug interaction with the diseased tissue.

CONCLUSION

This review focuses on the available targeting techniques for delivery to the colon, brain and other sites of interest. Overall, the article should make an excellent read for the researchers in this area. Newer drug targets may be identified and exploited for successful drug targeting.

Analysis of Fecal Primary Bile Acids Detects Increased Stool Weight and Colonic Transit in Patients With Chronic Functional Diarrhea

BACKGROUND & AIMS

Patients with bile acid diarrhea (BAD) are identified based on increased levels of BAs in fecal samples collected over a 48-hr period while on a 100-gram fat diet (48-hr BA), retention of ⁷⁵Se-labeled homocholic acid taurine, or serum levels of C4 or FGF19. BAD increases fecal weight and colonic transit. We investigated whether results of tests for BAD associate with increased fecal weight and more rapid colonic transit over a 24- or 48-hr period in patients with irritable bowel syndrome with diarrhea (IBS-D). We also estimated the prevalence of increased 48-hr fecal BAs in patients with chronic diarrhea.

METHODS

We performed a retrospective study of 64 patients with IBS-D, 30 patients with IBS-constipation, 30 healthy volunteers (controls). We collected data on fecal weights (measured over a 48-hr period), colonic transit over a 24-hr period (measured by scintigraphy), and percentages of different BAs in stool samples. Colonic transit was measured as the geometric center (weighted average) of colonic counts on a scale of 1 (100% in ascending colon) to 5 (100% in stool). We performed area under the curve (AUC) analyses to assess the association between result of serum and stool tests and high fecal weight (>400g/48 hrs) or rapid colonic transit (>3.34, corresponding to isotope geometric center in sigmoid colon). We estimated the prevalence of increased 48-hr fecal BAs among 938 patients with chronic diarrhea.

RESULTS

Total fecal 48-hr BA alone, or in combination with percentage of primary fecal BAs, identified patients with increased fecal weight with an AUROC of 0.86. Percentage of primary fecal BA alone identified patients with increased fecal weight with an AUROC of 0.73. Total fecal 48-hr BA alone identified patients with increased colonic transit with an AUROC of 0.65 and percentage of primary fecal BA alone identified patients with increased colonic transit with an AUROC of 0.69; combined data on these features identified patients with increased colonic transit with an AUROC of 0.70. Serum level of C4 identified patients with increased colonic transit with an AUROC of 0.60. Primary BAs >10% identified patients with increased fecal weight (sensitivity 49% and specificity 91%) and rapid colonic transit (sensitivity 48% and specificity 87%). Among the patients with chronic diarrhea, 45.6% had fecal primary BAs >10% and 27% had increased total fecal BAs (>2337 μmol/48 hrs).

CONCLUSIONS

In a retrospective analysis of patients with IBS-D, we found percentage of primary BAs in fecal samples to provide an alternative to total fecal BAs in identification of patients with BAD or chronic diarrhea.

Colonic N-methyl-d-aspartate receptor contributes to visceral hypersensitivity in irritable bowel syndrome

BACKGROUND AND AIMS

N-methyl-d-aspartate receptor (NMDAR) in brain, spinal cord, and enteric nervous system is involved in visceral hypersensitivity. This study aimed to reveal the functional expression of NMDAR on mucosal cells in colon and to investigate the downstream signal pathway from colonic NMDAR activation to visceral hypersensitivity in irritable bowel syndrome (IBS).

METHODS

The expression of mucosal NMDAR in IBS patients and healthy controls was assessed by immunohistochemistry and Western blot and correlated with abdominal pain/discomfort scores quantified by a validated questionnaire. Electromyography recording in response to colorectal distension was recorded to measure the colonic sensitivity of mice receiving NMDA administration intracolonically. Brain-derived neurotrophic factor (BDNF) expression and extracellular signal-regulated kinase (ERK) pathway activation were examined in human colonic epithelial HT29 cells after NMDA stimulation, with or without MK801 or U0126 pretreatment.

RESULTS

A significant upregulation of mucosal NMDAR was observed in IBS patients compared with controls, which was significantly correlated with abdominal pain/discomfort scores. Intracolonic administration of NMDA in normal mice produced increased colonic sensitivity to colorectal distension and elevated expression of BDNF and activation of ERK. Activation of NMDAR in colonic epithelial HT29 cells in vitro induced increased BDNF secretion in cell supernatants and higher BDNF expression in cells, as well as elevated phosphorylated ERK.

CONCLUSIONS

This study demonstrated that the activation of mucosal NMDAR in colon may contribute to the visceral hypersensitivity in IBS, by increasing production of BDNF in an ERK-dependent pathway.

Application of three-dimensional printing for colon targeted drug delivery systems

Orally administered solid dosage forms currently dominate over all other dosage forms and routes of administrations. However, human gastrointestinal tract (GIT) poses a number of obstacles to delivery of the drugs to the site of interest and absorption in the GIT. Pharmaceutical scientists worldwide have been interested in colon drug delivery for several decades, not only for the delivery of the drugs for the treatment of colonic diseases such as ulcerative colitis and colon cancer but also for delivery of therapeutic proteins and peptides for systemic absorption. Despite extensive research in the area of colon targeted drug delivery, we have not been able to come up with an effective way of delivering drugs to the colon. The current tablets designed for colon drug release depend on either pH-dependent or time-delayed release formulations. During ulcerative colitis the gastric transit time and colon pH-levels is constantly changing depending on whether the patient is having a relapse or under remission. Hence, the current drug delivery system to the colon is based on one-size-fits-all. Fails to effectively deliver the drugs locally to the colon for colonic diseases and delivery of therapeutic proteins and peptides for systemic absorption from the colon. Hence, to overcome the current issues associated with colon drug delivery, we need to provide the patients with personalized tablets which are specifically designed to match the individual's gastric transit time depending on the disease state. Three-dimensional (3D) printing (3DP) technology is getting cheaper by the day and bespoke manufacturing of 3D-printed tablets could provide the solutions in the form of personalized colon drug delivery system. This review provides a bird's eye view of applications and current advances in pharmaceutical 3DP with emphasis on the development of colon targeted drug delivery systems.

Colonic response to laxative ingestion as assessed by MRI differs in constipated irritable bowel syndrome compared to functional constipation

BACKGROUND

Functional constipation (FC) and irritable bowel syndrome with constipation (IBS-C) share many symptoms but underlying mechanisms may be different. We have developed a magnetic resonance imaging (MRI) technique to measure intestinal volumes, transit, and motility in response to a laxative, Moviprep(®) . We aim to use these biomarkers to study the pathophysiology in IBS-C and FC.

METHODS

Twenty-four FC and 24 IBS-C were studied. Transit was assessed using the weighted average position score (WAPS) of five MRI marker pills, taken 24 h before MRI scanning. Following baseline scan, participants ingested 1 L of Moviprep(®) followed by hourly scans. Magnetic resonance imaging parameters and bowel symptoms were scored from 0 to 4 h.

KEY RESULTS

Weighted average position score for FC was 3.6 (2.5-4.2), significantly greater than IBS-C at 2.0 (1.5-3.2), p = 0.01, indicating slower transit for FC. Functional constipation showed greater fasting small bowel water content, 83 (63-142) mL vs 39 (15-70) mL in IBS-C, p < 0.01 and greater ascending colon volume (AC), 314 (101) mL vs 226 (71) mL in IBS-C, p < 0.01. FC motility index was lower at 0.055 (0.044) compared to IBS-C, 0.107 (0.070), p < 0.01. Time to first bowel movement following ingestion of Moviprep(®) was greater for FC, being 295 (116-526) min, compared to IBS-C at 84 (49-111) min, p < 0.01, and correlated with AC volume 2 h after Moviprep(®) , r = 0.44, p < 0.01. Using a cut-off >230 min distinguishes FC from IBS-C with low sensitivity of 55% but high specificity of 95%.

CONCLUSION & INFERENCES

Our objective MRI biomarkers allow a distinction between FC and IBS-C.

Colonic mucosal gene expression and genotype in irritable bowel syndrome patients with normal or elevated fecal bile acid excretion

The mucosal gene expression in rectosigmoid mucosa (RSM) in irritable bowel syndrome with diarrhea (IBS-D) is unknown. Our objectives were, first, to study mRNA expression [by RT(2) PCR of 19 genes pertaining to tight junctions, immune activation, intestinal ion transport and bile acid (BA) homeostasis] in RSM in IBS-D patients (n = 47) and healthy controls (n = 17) and study expression of a selected protein (PDZD3) in 10 IBS-D patients and 4 healthy controls; second, to assess RSM mRNA expression according to genotype and fecal BA excretion (high ≥ 2,337 μmol/48 h); and third, to determine whether genotype or mucosal mRNA expression is associated with colonic transit or BA parameters. Fold changes were corrected for false detection rate for 19 genes studied (P < 0.00263). In RSM in IBS-D patients compared with controls, mRNA expression of GUC2AB, PDZD3, and PR2Y4 was increased, whereas CLDN1 and FN1 were decreased. One immune-related gene was upregulated (C4BP4) and one downregulated (CCL20). There was increased expression of a selected ion transport protein (PDZD3) on immunohistochemistry and Western blot in IBS-D compared with controls (P = 0.02). There were no significant differences in mucosal mRNA in 20 IBS-D patients with high compared with 27 IBS-D patients with normal BA excretion. GPBAR1 (P < 0.05) was associated with colonic transit. We concluded that mucosal ion transport mRNA (for several genes and PDZD3 protein) is upregulated and barrier protein mRNA downregulated in IBS-D compared with healthy controls, independent of genotype. There are no differences in gene expression in IBS-D with high compared with normal fecal BA excretion.

Intestinal secretory mechanisms in irritable bowel syndrome-diarrhea

Although diarrhea is the predominant bowel dysfunction in as many as one-third of patients with irritable bowel syndrome (IBS), it is unclear whether there is a specific disorder of intestinal fluid or electrolyte secretion in IBS. Diarrhea is generally considered a result of accelerated colonic transit in patients with IBS. Although a primary secretory diathesis has not been well-documented in patients with IBS with diarrhea (IBS-D), several mechanisms that could potentially contribute to intestinal secretion have been reported. Some of these mechanisms also influence motor and secretory dysfunctions that contribute to the pathophysiology of IBS-D. We review the evidence supporting secretion in IBS-D caused by peptides and amines produced by enteroendocrine cells or submucosal neurons, enterocyte secretory processes, and intraluminal factors (bile acids and short-chain fatty acids). Understanding these mechanisms and developing clinical methods for their identification could improve management of patients with IBS-D.

A randomized trial of 5-hydroxytryptamine4-receptor agonist, YKP10811, on colonic transit and bowel function in functional constipation

BACKGROUND & AIMS

YKP10811, a selective agonist of the serotonin 5-hydroxytryptamine-4 receptor, increases gastrointestinal (GI) motility. We investigated the safety and effects of YKP10811 on GI and colonic transit and bowel movements (BMs) in patients with functional constipation in a randomized, double-blind, placebo-controlled study.

METHODS

Patients with functional constipation, based on the Rome III criteria, were assigned randomly to groups given YKP10811 10 mg (n = 15), 20 mg (n = 16), 30 mg (n = 15), or placebo (n = 11) daily for 8 days. Transit of solids was measured by validated scintigraphy at baseline and on days 7 to 9. Patients kept diaries on days 1 to 9, recording time to first BM, number of BMs/day, and stool consistency (based on the Bristol Stool Form Scale). To evaluate safety, we collected data on adverse events and clinical laboratory test and electrocardiograms results. The primary efficacy end points were determined from an intent-to-treat analysis assessing colonic transit at 24 hours and the half-time (t1/2) of gastric emptying, using analysis of covariance models. Secondary efficacy end points included measures of colonic transit (geometric center at 4 and 24 hours), small-bowel transit (based on colon filling at 6 hours), t1/2 of ascending colon emptying, and bowel functions. We used the Dunnett test to compare the effects of each dose with placebo. A per-protocol analysis (PPA) assessed the t1/2 of gastric emptying and time to first BM using proportional hazards models.

RESULTS

Fifty-five participants completed the study. YKP10811 was associated with a significant acceleration in colon filling at 6 hours (P < .05), t1/2 of ascending colon emptying, and colonic transit at 24 and 48 hours, as well as increased stool consistency over 8 days (based on intent-to-treat analysis). In general, the 10-mg and 20-mg doses were the most effective in accelerating colonic transit. No serious adverse events were observed.

CONCLUSIONS

YKP10811, a selective agonist of the serotonin receptor 5-hydroxytryptamine-4, accelerates GI and colonic transit and improves bowel functions in patients with functional constipation, compared with placebo. ClinicalTrial.Gov: NCT01523184.

Cinnamate of inulin as a vehicle for delivery of colonic drugs

Colon diseases are difficult to treat because oral administrated drugs are absorbed at the stomach and intestine levels and they do not reach colon; in addition, intravenous administrated drugs are eliminated from the body before reaching colon. Inulin is a naturally occurring polysaccharide found in many plants. It consists of β 2-1 linked D-fructose molecules having a glucosyl unit at the reducing end. Various inulin and dextran hydrogels have been developed that serve as potential carrier for introduction of drugs into the colon. Because inulin is not absorbed in the stomach or in the small intestine, and inulin is degraded by colonic bacteria, drugs encapsulated in inulin-coated vesicles could be specifically liberated in the colon. Therefore, the use of inulin-coated vesicles could represent an advance for the treatment of colon diseases. Here, we study the use of a cinnamoylated derivative of chicory inulin as a vehicle for the controlled delivery of colonic drugs. The encapsulation of methotrexate in inulin vesicles and its release and activity was studied in colon cancer cells in cultures.

Stimulation of colonic motility by oral PEG electrolyte bowel preparation assessed by MRI: comparison of split vs single dose

BACKGROUND

Most methods of assessing colonic motility are poorly acceptable to patients. Magnetic resonance imaging (MRI) can monitor gastrointestinal motility and fluid distributions. We predicted that a dose of oral polyethylene glycol (PEG) and electrolyte solution would increase ileo-colonic inflow and stimulate colonic motility. We aimed to investigate the colonic response to distension by oral PEG electrolyte in healthy volunteers (HVs) and to evaluate the effect of single 2 L vs split (2 × 1 L) dosing.

METHODS

Twelve HVs received a split dose (1 L the evening before and 1 L on the study day) and another 12 HVs a single dose (2 L on the main study day) of PEG electrolyte. They underwent MRI scans, completed symptom questionnaires, and provided stool samples. Outcomes included small bowel water content, ascending colon motility index, and regional colonic volumes.

KEY RESULTS

Small bowel water content increased fourfold from baseline after ingesting both split (p = 0.0010) and single dose (p = 0.0005). The total colonic volume increase from baseline was smaller for the split dose at 35 ± 8% than for the single dose at 102 ± 27%, p = 0.0332. The ascending colon motility index after treatment was twofold higher for the single dose group (p = 0.0103).

CONCLUSIONS & INFERENCES

Ingestion of 1 and 2 L PEG electrolyte solution caused a rapid increase in the small bowel and colonic volumes and a robust rise in colonic motility. The increase in both volumes and motility was dose dependent. Such a challenge, being well-tolerated, could be a useful way of assessing colonic motility in future studies.

Association of cannabinoid type 1 receptor and fatty acid amide hydrolase genetic polymorphisms in Chinese patients with irritable bowel syndrome

BACKGROUND AND AIM

The endocannabinoid system is involved in the pathophysiology of irritable bowel syndrome (IBS). Here, we investigated whether genetic variants of the cannabinoid type 1 receptor (CNR1) and fatty acid amide hydrolase (FAAH) are associated with the pathogenesis of IBS.

METHODS

In total, 292 patients with IBS and 298 healthy controls were enrolled. Polymerase chain reaction (PCR) and DNA sequencing were applied to determine the genotyping of polymorphic triplet AAT repeats located at the 3'-end of the CNR1 gene. The single nucleotide polymorphism (SNP) C385A at the FAAH gene (rs324420) was determined by PCR using TaqMan SNP Genotyping Assay Sets.

RESULTS

A total of eight alleles with AAT triplet repeats in the CNR1 gene were detected. The alleles were divided into two groups (≤ 10 and > 10) and three genotypes (≤ 10/≤ 10, ≤ 10/> 10, and > 10/> 10). The frequency of > 10 alleles was significantly higher in the IBS group (90.6%) when compared with the control group {81.7%, P < 0.001, odds ratio (OR) (95% confidence interval [CI]) = -0.128}. In addition, the genotypes > 10/> 10 were significantly associated with IBS (P < 0.001, OR [95% CI] = -0.163). The frequency of the A allele and the distribution of the AA genotype in the FAAH gene in the IBS group were not significantly different from those in the control group (P > 0.05), even though the frequency of the AA genotype was lower in the IBS group (1.0%) than that in the control group (3.4%, P = 0.089, OR [95% CI] = 3.345).

CONCLUSIONS

The variation in the (AAT)n repeat of the CNR1 gene conferred an increased risk for developing IBS, while rs324420 (C385) in the FAAH gene was not associated with IBS pathogenesis.

Carboxymethylcellulose-tetrahydrocurcumin conjugates for colon-specific delivery of a novel anti-cancer agent, 4-amino tetrahydrocurcumin

Several curcumin derivatives are now becoming increasingly of interest because of their bioactive attributes, especially their action as antioxidants and anti-carcinogenic activities. Tetrahydrocurcumin (THC), an active metabolite of curcumin, was selected to be a proper starting material for the work presented here as it is stable in physiological pH and has the typical pharmacological properties of curcumin. We have now reported that novel synthesized water-soluble polymeric macromolecule prodrugs can specifically deliver the drug to the colon. To study the drug loading and drug release, THC was conjugated with a hydrophilic polymer, carboxymethylcellulose (CMC) with the degree of substitution (DS) values of 0.7 and 1.2. THC was also attached to two different spacers including p-aminobenzoic acid (PABA) and p-aminohippuric acid (PAH) via an azo bond that was cleaved by the azoreductase activities of colonic bacteria. The novel active molecule, 4-amino-THC, was readily released from the conjugates in the colon (>62% within 24h) with only very small amounts released in the upper GI tract (<12% over 12h). The polymer conjugates showed chemical stability at various pH values along the gastrointestinal tract and increased water solubility of up to 5mg/mL. 4-Amino-THC demonstrated cytotoxic ability against the human colon adenocarcinoma cell lines (HT-29) with an IC50 of 28.67 ± 1.01 μg/mL, and even greater selectivity (∼ 4 folds) to inhibit HT-29 cells than to normal human colon epithelial cell lines while curcumin was a non-selective agent against both cell lines. Our study has demonstrated that the use of THC-CMC conjugates may be a promising colon-specific drug delivery system with its sustained release in the colon to be an effective treatment for colonic cancer.

Novel MRI tests of orocecal transit time and whole gut transit time: studies in normal subjects

BACKGROUND

Colonic transit tests are used to manage patients with Functional Gastrointestinal Disorders. Some tests used expose patients to ionizing radiation. The aim of this study was to compare novel magnetic resonance imaging (MRI) tests for measuring orocecal transit time (OCTT) and whole gut transit time (WGT), which also provide data on colonic volumes.

METHODS

21 healthy volunteers participated. Study 1: OCTT was determined from the arrival of the head of a meal into the cecum using MRI and the Lactose Ureide breath test (LUBT), performed concurrently. Study 2: WGT was assessed using novel MRI marker capsules and radio-opaque markers (ROMs), taken on the same morning. Studies were repeated 1 week later.

KEY RESULTS

OCTT measured using MRI and LUBT was 225 min (IQR 180-270) and 225 min (IQR 165-278), respectively, correlation r(s) = 0.28 (ns). WGT measured using MRI marker capsules and ROMs was 28 h (IQR 4-50) and 31 h ± 3 (SEM), respectively, correlation r(s) = 0.85 (p < 0.0001). Repeatability assessed using the intraclass correlation coefficient (ICC) was 0.45 (p = 0.017) and 0.35 (p = 0.058) for MRI and LUBT OCTT tests. Better repeatability was observed for the WGT tests, ICC being 0.61 for the MRI marker capsules (p = 0.001) and 0.69 for the ROM method (p < 0.001) respectively.

CONCLUSIONS & INFERENCES

The MRI WGT method is simple, convenient, does not use X-ray and compares well with the widely used ROM method. Both OCTT measurements showed modest reproducibility and the MRI method showed modest inter-observer agreement.

Fasting and postprandial volumes of the undisturbed colon: normal values and changes in diarrhea-predominant irritable bowel syndrome measured using serial MRI

BACKGROUND

Previous assessments of colon morphology have relied on tests which were either invasive or used ionizing radiation. We aimed to measure regional volumes of the undisturbed colon in healthy volunteers (HV) and patients with diarrhea-predominant irritable bowel syndrome (IBS-D).

METHODS

3D regional (ascending, transverse, and descending) colon volumes were measured in fasting abdominal magnetic resonance (MR) images of 75 HVs and 25 IBS-D patients. Thirty-five of the HV and all 25 IBS-D subjects were fed a standard meal and postprandial MRI data obtained over 225 min.

KEY RESULTS

Colonic regions were identified and 3D maps from cecum to sigmoid flexure were defined. Fasted regional volumes showed wide variation in both HVs being (mean ± SD) ascending colon (AC) 203 ± 75 mL, transverse (TC) 198 ± 79 mL, and descending (DC) 160 ± 86 mL with no difference from IBS-D subjects (AC 205 ± 69 mL, TC 232 ± 100 mL, and DC 151 ± 71 mL, respectively). The AC volume expanded by 10% after feeding (p = 0.007) in the 35 HV possibly due to increased ileo-colonic inflow. A later rise in AC volume occurred from t = 90 to t = 240 min as the meal residue entered the cecum. In contrast, IBS-D subjects showed a much reduced postprandial response of the AC (p < 0.0001) and a greater increase in TC volume after 90 min (p = 0.0244) compared to HV.

CONCLUSIONS & INFERENCES

We have defined a normal range of the regional volumes of the undisturbed colon in fasted and fed states. The AC in IBS-D appeared less able to accommodate postprandial inflow which may account for faster colonic transit.

[The prevalence of irritable bowel symptoms in a population of shopping mall visitors in Santiago de Chile]

BACKGROUND

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain or discomfort that is associated with altered bowel habit. Both its prevalence and clinical characteristics vary throughout Latin America. A percentage of patients does not seek medical attention, therefore a reliable prevalence figure can only be established by interviewing non-selected populations.

AIMS

To study the prevalence and clinical characteristics of IBS symptoms in non-selected subjects in Santiago, Chile.

METHODS

A total of 437 shopping mall visitors above the age of 15 years (246 women) participated in the study by answering the Rome II validated questionnaire for IBS. The demographic and socioeconomic backgrounds, comorbidities, and a family history of IBS were registered.

RESULTS

A total of 64.1% subjects reported having gastrointestinal symptoms and 28.6% had symptoms suggestive of IBS. When the subjects with IBS symptoms were compared with the asymptomatic individuals, a predominance of women (65.6 vs. 42.9, P<.001) and a greater cholecystectomy frequency (33.6 vs. 12.9% P<.05) were observed in the former. The age of symptom onset was 30.4 years. An equal percentage of subjects (42.4%) presented with diarrhea and constipation and 15.2% presented with alternating IBS. Participants with a higher educational level reported a lower percentage of IBS (P<.05). A family history of the disease was present in 40% of the subjects with IBS, compared with 14.9% in the asymptomatic individuals (P<.05). Only 39.2% of the subjects had seen a physician for their symptoms and the treatment and tests ordered were inappropriate.

CONCLUSION

The prevalence of IBS symptoms in the population studied is one of the highest described. Therefore, health teams should have the necessary knowledge and skill required for its management.

Current and future pharmacological treatments for diarrhea-predominant irritable bowel syndrome

INTRODUCTION

Diarrhea-predominant irritable bowel syndrome (IBS-D) affects about one-third of patients with IBS, which is observed in about 12% of people across five continents. The ultimate goal in this field is to identify the underlying cause of symptoms in order to individualize education of the patient, and to provide optimal treatment of this highly prevalent condition.

AREAS COVERED

This review addresses the pharmacological treatments for IBS-D under three categories: drugs for IBS-D (i.e., the 5-HT3 antagonist, alosetron); drugs approved for other indications that are used in IBS-D (e.g., opioid agonists; other 5-HT3 antagonists; serotonergic psychoactive agents; bile acid binders; 5-ASA compounds; probiotics and non-absorbable antibiotics); as well as development of drugs that are likely to impact the management of IBS-D in the future (e.g., drug absorbents; TPH1 inhibitors; mast cell stabilizers; centrally acting benzodiazepines). The final section addresses key findings: regulatory roadblocks; weaknesses in the current research in this field so far and opportunities to address unmet needs including restoration of normal intestinal barrier function or permeability, and suppression within the intestines of local immune activation that is thought to trigger abnormal motor, sensory and secretory functions in IBS-D.

EXPERT OPINION

While symptomatic treatment of diarrhea is effective, there is a need for new treatments for the IBS-D complex. Greater understanding of the mechanisms in IBS-D has led to promising approaches to develop more efficacious therapies.

Stool characteristics and colonic transit in irritable bowel syndrome: evaluation at two time points

OBJECTIVE

Information on the relationships between stool characteristics and colonic transit time (CTT) in irritable bowel syndrome (IBS) is limited. Our aims were: (i) to relate stool frequency and consistency to total and segmental CTTs, (ii) to correlate changes in these stool characteristics with changes in CTTs between a baseline assessment and a 12-week assessment, and (iii) to examine the confounding effects of mood on these relationships, in patients with IBS.

MATERIALS AND METHODS

Twenty-one female patients with IBS underwent, on two occasions 12 weeks apart, a colonic transit study and completed at these times Bristol Stool Form Scale (BSFS) and Bowel Symptoms Severity Rating Scale (BSSRS). All patients also completed the Hospital Anxiety and Depression scale.

RESULTS

Between baseline and the 12-week assessment, an increase in the number of days over the past week without a bowel motion correlated with prolonged total CTT (r = 0.54, p = 0.01). An increase in the number of days with more than three bowel motions per day correlated with a shorter right CTT (r = -0.52, p = 0.02). Only after adjusting for anxiety and depression, did an increase in loose or watery bowel motions (for BSSRS but not for BSFS) correlate with a shorter right CTT (r = -0.47, p = 0.03).

CONCLUSIONS

Stool frequency, as well as stool consistency, correlates with CTT. Correlations between stool consistency and CTT are more robust for BSSRS than for BSFS. An effect of mood appears to be important in the relationship between stool consistency and CTT.

Targeting the endocannabinoid system for gastrointestinal diseases: future therapeutic strategies

Cannabinoids extracted from the marijuana plant (Cannabis sativa) and synthetic cannabinoids have numerous effects on gastrointestinal (GI) functions. Recent experimental data support an important role for cannabinoids in GI diseases. Genetic studies in humans have proven that defects in endocannabinoid metabolism underlie functional GI disorders. Mammalian cells have machinery, the so-called endocannabinoid system (ECS), to produce and metabolize their own cannabinoids in order to control homeostasis of the gut in a rapidly adapting manner. Pharmacological manipulation of the ECS by cannabinoids, or by drugs that raise the levels of endogenous cannabinoids, have shown beneficial effects on GI pathophysiology. This review gives an introduction into the functions of the ECS in the GI tract, highlights the role of the ECS in GI diseases and addresses its potential pharmacological exploitation.

Methods for the assessment of small-bowel and colonic transit

Transit assessment of the small intestine and colon is relevant in the study of physiology, pathophysiology, and pharmacodynamics, and there is increasing use of small-bowel and colonic transit measurements in clinical practice as well. The main methods that are applied in clinical practice are substrate-hydrogen breath tests for small-bowel transit and radiopaque markers for colonic transit. Over the past 2-3 decades, scintigraphy has become the preferred standard in research studies, particularly for studies of pathophysiology and pharmacodynamics. New approaches include experimental stable isotope measurement of orocecal transit and the recently approved method using a wireless motility capsule that is validated as an accurate measurement of small-bowel and colonic transit.

Anti-stress effects of transcutaneous electrical nerve stimulation (TENS) on colonic motility in rats

BACKGROUND

Disorders of colonic motility may contribute to symptoms in patients with irritable bowel syndrome (IBS), and stress is widely believed to play a major role in developing IBS. Stress increases corticotropin releasing factor (CRF) of the hypothalamus, resulting in acceleration of colonic transit in rodents. In contrast, hypothalamic oxytocin (OXT) has an anti-stress effect via inhibiting CRF expression and hypothalamic-pituitary-adrenal axis activity. Although transcutaneous electrical nerve stimulation (TENS) and acupuncture have been shown to have anti-stress effects, the mechanism of the beneficial effects remains unknown.

AIMS

We tested the hypothesis that TENS upregulates hypothalamic OXT expression resulting in reduced CRF expression and restoration of colonic dysmotility in response to chronic stress.

METHODS

Male SD rats received different types of stressors for seven consecutive days (chronic heterotypic stress). TENS was applied to the bilateral hind limbs every other day before stress loading. Another group of rats did not receive TENS treatment.

RESULTS

TENS significantly attenuated accelerated colonic transit induced by chronic heterotypic stress, which was antagonized by a central injection of an OXT antagonist. Immunohistochemical study showed that TENS increased OXT expression and decreased CRF expression at the paraventricular nucleus (PVN) following chronic heterotypic stress.

CONCLUSIONS

It is suggested that TENS upregulates hypothalamic OXT expression which acts as an anti-stressor agent and mediates restored colonic dysmotility following chronic stress. TENS may be useful to treat gastrointestinal symptoms associated with stress.

Impaired adaptation of gastrointestinal motility following chronic stress in maternally separated rats

Exposure to early life stress causes increased stress responsiveness and permanent changes in the central nervous system. We recently showed that delayed gastric emptying (GE) and accelerated colonic transit (CT) in response to acute restraint stress (ARS) were completely restored following chronic homotypic stress (CHS) in rats via upregulation of hypothalamic oxytocin (OXT) expression. However, it is unknown whether early life stress affects hypothalamic OXT circuits and gastrointestinal motor function. Neonatal rats were subjected to maternal separation (MS) for 180 min/day for 2 wk. Anxiety-like behaviors were evaluated by the elevated-plus-maze test. GE and CT were measured under nonstressed (NS), ARS, and CHS conditions. Expression of corticotropin-releasing factor (CRF) and OXT in the paraventricular nucleus (PVN) of the hypothalamus was evaluated by real time RT-PCR and immunohistochemistry. MS increased anxiety-like behaviors. ARS delayed GE and accelerated CT in control and MS rats. After CHS, delayed GE and accelerated CT were restored in control, but not MS, rats. CRF mRNA expression was significantly increased in response to ARS in control and MS rats. Increased CRF mRNA expression was still observed following CHS in MS, but not control, rats. In response to CHS, OXT mRNA expression was significantly increased in control, but not MS, rats. The number of OXT-immunoreactive cells was increased following CHS in the magnocellular part of the PVN in control, but not MS, rats. MS impairs the adaptation response of gastrointestinal motility following CHS. The mechanism of the impaired adaptation involves downregulation of OXT and upregulation of CRF in the hypothalamus in MS rats.

Plasma hormones facilitated the hypermotility of the colon in a chronic stress rat model

Objective

To study the relationship between brain-gut peptides, gastrointestinal hormones and altered motility in a rat model of repetitive water avoidance stress (WAS), which mimics the irritable bowel syndrome (IBS).

Methods

Male Wistar rats were submitted daily to 1-h of water avoidance stress (WAS) or sham WAS (SWAS) for 10 consecutive days. Plasma hormones were determined using Enzyme Immunoassay Kits. Proximal colonic smooth muscle (PCSM) contractions were studied in an organ bath system. PCSM cells were isolated by enzymatic digestion and IKv and IBKca were recorded by the patch-clamp technique.

Results

The number of fecal pellets during 1 h of acute restraint stress and the plasma hormones levels of substance P (SP), thyrotropin-releasing hormone (TRH), motilin (MTL), and cholecystokinin (CCK) in WAS rats were significantly increased compared with SWAS rats, whereas vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP) and corticotropin releasing hormone (CRH) in WAS rats were not significantly changed and peptide YY (PYY) in WAS rats was significantly decreased. Likewise, the amplitudes of spontaneous contractions of PCSM in WAS rats were significantly increased comparing with SWAS rats. The plasma of WAS rats (100 µl) decreased the amplitude of spontaneous contractions of controls. The IKv and IBKCa of PCSMs were significantly decreased in WAS rats compared with SWAS rats and the plasma of WAS rats (100 µl) increased the amplitude of IKv and IBKCa in normal rats.

Conclusion

These results suggest that WAS leads to changes of plasma hormones levels and to disordered myogenic colonic motility in the short term, but that the colon rapidly establishes a new equilibrium to maintain the normal baseline functioning.

Potential biomarkers

A "biomarker" (biological marker) is an indicator of a bodily function that can be objectively measured. A wide range of possible biomarkers for IBS have been considered but at present only gut transit measured using radio-isotope markers meet the criteria of reproducibility and availability. While barostat studies perform reasonably in expert centers, to do them reproducibly requires considerable effort and standardization. This makes them unsuitable for widespread use. However radio-isotope tests are expensive and of limited availability so the search for other more convenient markers including blood and stool tests is still an important goal for the future.

Proteomic analysis of colonic mucosa in a rat model of irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common functional disorders of the gastrointestinal tract. It is characterized by abdominal pain and changes in bowel habits. Various studies have investigated the pathophysiologic processes underlying IBS, but the mechanism remains poorly understood. In the present study, we established an IBS model and identified differentially expressed proteins in colon tissue of IBS rats compared with healthy controls by 2-D gel electrophoresis, MALDI-TOF-MS, and Western blot analysis. Our results showed that 13 of the 1396 protein spots on 2-D gel were differently expressed between the IBS and control groups. Ontological analysis of these proteins revealed primary roles in catalytic activity (protein disulfide-isomerase A3, glyoxalase I, cathepsin S, alpha-enolase), structural support (cytokeratin 8), antioxidant activity (peroxiredoxin-6), protein binding (transgelin, serpin peptidase inhibitor B5), and signal transduction (40S ribosomal protein SA). Protein disulfide-isomerase A3 and cytokeratin 8 overexpression in IBS were confirmed by Western blot. The findings indicate that multiple proteins are involved in IBS processes that influence intestinal tract immunity, inflammation, and nerve regulation. Our study provides useful candidate genes and proteins for further investigation.

Asian consensus on irritable bowel syndrome

BACKGROUND AND AIMS

Many of the ideas on irritable bowel syndrome (IBS) are derived from studies conducted in Western societies. Their relevance to Asian societies has not been critically examined. Our objectives were to bring to attention important data from Asian studies, articulate the experience and views of our Asian experts, and provide a relevant guide on this poorly understood condition for doctors and scientists working in Asia.

METHODS

A multinational group of physicians from Asia with special interest in IBS raised statements on IBS pertaining to symptoms, diagnosis, epidemiology, infection, pathophysiology, motility, management, and diet. A modified Delphi approach was employed to present and grade the quality of evidence, and determine the level of agreement.

RESULTS

We observed that bloating and symptoms associated with meals were prominent complaints among our IBS patients. In the majority of our countries, we did not observe a female predominance. In some Asian populations, the intestinal transit times in healthy and IBS patients appear to be faster than those reported in the West. High consultation rates were observed, particularly in the more affluent countries. There was only weak evidence to support the perception that psychological distress determines health-care seeking. Dietary factors, in particular, chili consumption and the high prevalence of lactose malabsorption, were perceived to be aggravating factors, but the evidence was weak.

CONCLUSIONS

This detailed compilation of studies from different parts of Asia, draws attention to Asian patients' experiences of IBS.

Colon targeted drug delivery systems: a review on primary and novel approaches

The colon is a site where both local and systemic delivery of drugs can take place. Local delivery allows topical treatment of inflammatory bowel disease. However, treatment can be made effective if the drugs can be targeted directly into the colon, thereby reducing the systemic side effects. This review, mainly compares the primary approaches for CDDS (Colon Specific Drug Delivery) namely prodrugs, pH and time dependent systems, and microbially triggered systems, which achieved limited success and had limitations as compared with newer CDDS namely pressure controlled colonic delivery capsules, CODESTM, and osmotic controlled drug delivery which are unique in terms of achieving in vivo site specificity, and feasibility of manufacturing process.

Asian motility studies in irritable bowel syndrome

Altered motility remains one of the important pathophysiologic factors in patients with irritable bowel syndrome (IBS) who commonly complain of abdominal pain and stool changes such as diarrhea and constipation. The prevalence of IBS has increased among Asian populations these days. Gastrointestinal (GI) physiology may vary between Asian and Western populations because of differences in diets, socio-cultural backgrounds, and genetic factors. The characteristics and differences of GI dysmotility in Asian IBS patients were reviewed. MEDLINE search work was performed including following terms, 'IBS,' 'motility,' 'transit time,' 'esophageal motility,' 'gastric motility,' 'small intestinal motility,' 'colonic motility,' 'anorectal function,' and 'gallbladder motility' and over 100 articles were categorized under 'esophagus,' 'stomach,' 'small intestine,' 'colon,' 'anorectum,' 'gallbladder,' 'transit,' 'motor pattern,' and 'effect of stressors.' Delayed gastric emptying, slow tansit in constipation predominant IBS patients, rapid transit in diarrhea predominant IBS patients, accelerated motility responses to various stressors such as meals, mental stress, or corticotrophin releasing hormones, and altered rectal compliance and altered rectal accomodation were reported in many Asian studies regarding IBS. Many conflicting results were found among these studies and there are still controversies to conclude these as unique features of Asian IBS patients. Multinational and multicenter studies are needed to be performed vigorously in order to elaborate characteristics as well as differences of altered motililty in Asian patients with IBS.

Lower functional gastrointestinal disorders: evidence of abnormal colonic transit in a 287 patient cohort

BACKGROUND Abnormalities of colonic motility were reported in relatively small studies of patients with lower functional gastrointestinal disorders (FGID) including irritable bowel syndrome (IBS). The influence of gender and body mass on the observed motor pathophysiology is unclear. We sought to compare colonic transit in patients within different lower FGID subgroups and healthy controls, controlling for gender and BMI, and to determine whether BMI independently influences colonic motility. METHODS We evaluated a scintigraphic gastrointestinal and colonic transit database of 287 lower FGID patients associated with constipation (IBS-C, or functional constipation, n = 118), diarrhoea (IBS-D or functional diarrhoea, n = 139) or mixed bowel function (IBS-M, n = 30) and 170 healthy controls. We measured colon filling at 6 h (CF 6 h), and overall colonic transit at 8, 24 and 48 h. KEY RESULTS Colon filling at 6 h did not differentiate health from FGID. Colonic transit was abnormal at 24 h (GC24 of <1.50 or >3.86) in 29.7% of all lower FGID patients. There was a significant overall association between colonic transit and subject group (healthy controls and FGID subgroups) at 8 (P = 0.01), 24 (P < 0.001) and 48 h (P < 0.001) in particular for those with diarrhoea or constipation at 24 and 48 h (P < 0.05), even after adjusting for age, gender and BMI. In addition, BMI was associated with colonic transit after adjusting for age, gender and subject group. CONCLUSIONS & INFERENCES Abnormal transit is documented non-invasively with scintigraphy in 30% of lower FGID patients; transit measurement may help document pathophysiology and inform selection of therapy in lower FGID.

Eradication of Blastocystis carriage with antimicrobials: reality or delusion?

Metronidazole constitutes a mainstay in the antimicrobial therapy of intestinal protozoa, and is also traditionally considered first-line therapy in cases where there is a requirement to treat Blastocystis, a common protist of disputable clinical significance. Many compounds have been used in attempts to eradicate the parasite, and an accumulating body of data indicates that successful antimicrobial eradication of Blastocystis is far from straightforward. This review focuses on some issues that prevent us from reaching a clear understanding of how to eradicate Blastocystis based on chemotherapeutic intervention, by focusing on conflicting reports on the efficacy of metronidazole and other compounds and study design and data limitations. The review provides a comprehensive overview of antimicrobials used to target Blastocystis, and discusses issues pertaining to drug resistance, treatment failure, and reinfection. Finally, key methodological and molecular diagnostic tools that will assist in the generation of data required to improve current knowledge are identified and discussed.

Rectal distensibility and symptoms after stapled and Milligan-Morgan operation for hemorrhoids

INTRODUCTION

In a previous uncontrolled study, a reduction of rectal distensibility and volume thresholds for sensations have been related to the occurrence of fecal urgency and/or increased stool frequency after stapled hemorrhoidopexy.

AIM OF THE STUDY

The aim of this study was to compare rectal symptoms and sensory-motor function after stapled hemorrhoidopexy and Milligan-Morgan hemorrhoidectomy.

METHODS

The clinical records of 12 (four women) and ten patients (four women) with third- and fourth-degree hemorrhoids, respectively, who underwent stapled hemorrhoidopexy or Milligan-Morgan's hemorrhoidectomy, were evaluated. One week before and 6 months after surgery, rectal motor and sensory response to distension was assessed by an electronic barostat, and bowel and rectal symptoms were recorded by means of a 7-day diary and Bristol Index scale and psychological symptoms with SCL-90 questionnaire.

RESULTS

Rectal distensibility and volume thresholds for sensations were significantly lower after surgery (P < 0.02) in the stapled group. Increased stool frequency and/or fecal urgency arose in 41% of patients in the stapled group and associated with altered rectal distensibility. No difference within and between groups could be demonstrated in SCL-90 score.

CONCLUSIONS

Rectal distensibility and volume thresholds for sensations decrease after stapled hemorrhoidopexy. Altered rectal distensibility was associated with rectal urgency and/or increased stool frequency.

Peripheral factors in the pathophysiology of irritable bowel syndrome

The pathophysiology of IBS is complex and still incompletely known. Both central and peripheral factors are thought to contribute to the symptoms of IBS, including psychosocial factors, abnormal GI motility and secretion, and visceral hypersensitivity. In this review the involvement of peripheral factors in the pathophysiology in IBS is reviewed. Altered GI motility is commonly found in this patient group, even though a specific motor pattern has been hard to find. Colonic transit has been found to be of relevance for the bowel habit of the patient. Abnormal gas handling within the gut is also commonly seen, and seems to be one, but not the only factor responsive for bloating. There is also limited evidence supporting the presence of abnormal GI secretion in IBS, but its relevance for symptoms remains unclear. Visceral hypersensitivity is currently considered to be one of the most important pathophysiological factors in IBS. It can be modulated by several external and internal factors and recent studies support an association between colorectal sensitivity and the symptoms reported by the patients, especially pain.

The language of medicine: words as servants and scoundrels

Progress in complex disorders requires clear thinking facilitated by clear language. Clinicians and scientists occasionally become captive to inaccurate language or meaningless terminology and this generates lazy thinking and impedes progress. Has this happened in the case of the functional gastrointestinal disorders (FGIDs), in general, and irritable bowel syndrome (IBS), in particular? FGIDs and, especially IBS, are common illnesses and an important burden on healthcare resources but, in general, have suffered from a lack of progress in the development of safe and effective treatment. Among FGIDs, IBS may be the best defined but significant lapses of accuracy in terminology persist. Among other FGIDs, the situation is more serious; imprecision and lack of consistency in terminology continue to mar progress. This article reviews the chequered history of terminology in this area and concludes that removing the obfuscation generated by poor usage of language should be the first step towards understanding the pathogenesis and improving the management of these, and similar, disorders.

The role of the endocannabinoid system in the pathophysiology and treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a spectrum of disorders characterized by abdominal discomfort and pain, associated with altered bowel habits. Though gut motility, secretion and sensation may be altered in patients with IBS, the pathophysiology of this condition remains to be fully understood. The endocannabinoid system is involved in the regulation of numerous gastrointestinal functions including motility, sensation and secretion under both physiological and pathophysiological conditions. Activation of cannabinoid (CB)(1) and CB(2) receptors under various circumstances reduces motility, limits secretion and decreases hypersensitivity in the gut. Drugs that alter the levels of endocannabinoids in the gut also reduce motility and attenuate inflammation. In this review, we discuss the role of the endocannabinoid system in gastrointestinal physiology. We go on to consider the involvement of the endocannabinoid system in the context of symptoms associated with IBS and a possible role of this system in the pathophysiology and treatment of IBS.