Development and validation of a prediction model for histologic progression in patients with nondysplastic Barrett's esophagus

OBJECTIVES

Patients with Barrett's esophagus (BE) are at risk of progression to esophageal adenocarcinoma (EAC). We developed a model to predict histologic progression in patients with nondysplastic BE (NDBE).

METHODS

A longitudinal study in three referral centers was performed between January 2010 and December 2019. As progression to low-grade dysplasia (LGD) can be considered an indication for ablative therapy, the study end-point was histopathologic progression to LGD, high-grade dysplasia, or EAC at 3 years after diagnosis. We used logistic regression to create the model. Seventy percent of the cohort were used to stem the model and the remaining 30% for internal validation.

RESULTS

A total of 542 patients were included, 69.4% of whom were male, mean age 62.2 years. Long-segment BE at index endoscopy was diagnosed in 20.8% of the patients. After a mean follow-up of 6.7 years, 133 patients (24.5%) had histologic progression. Our model identified a neutrophil-to-lymphocyte ratio (odds ratio [OR] 2.08, 95% confidence interval [CI] 1.77-2.32, P < 0.001), BE length (OR 1.22, 95% CI 1.09-1.36, P < 0.001), age (OR 1.03, 95% CI 1.02-1.05, P = 0.02), smoking (OR 1.66, 95% CI 1.09-2.75, P = 0.04), and renal failure (OR 1.51, 95% CI 0.93-2.43, P = 0.07) as predictors of histologic progression at 3 years. The areas under the receiver operating characteristic curves of this model were 0.88 and 0.76 in the training and validation cohorts, respectively.

CONCLUSION

This novel, internally validated model may predict histologic progression, even in patients with NDBE who generally have low rates of progression over time, and may contribute to enhanced patient selection for more intense surveillance programs.

Noninvasive imaging and quantification of bile salt hydrolase activity: From bacteria to humans

The microbiome-produced enzyme bile salt hydrolase (BSH) plays a central role in human health, but its function remains unclear due to the lack of suitable methods for measuring its activity. Here, we have developed a novel optical tool based on ultrasensitive bioluminescent imaging and demonstrated that this assay can be used for quick and cost-effective quantification of BSH activity across a broad range of biological settings including pure enzymes and bacteria, intact fecal slurries, and noninvasive imaging in live animals, as well as for the assessment of BSH activity in the entire gastrointestinal tract of mice and humans. Using this assay, we showed that certain types of prebiotics are capable of increasing BSH activity of the gut microbiota in vivo and successfully demonstrated potential application of this assay as a noninvasive diagnostic test to predict the clinical status of inflammatory bowel disease (IBD) patients.

The Thrilling Journey of SARS-CoV-2 into the Intestine: From Pathogenesis to Future Clinical Implications

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has a direct impact on the gastrointestinal system, as up to 50% of fecal samples from coronavirus disease 2019 (COVID-19) patients contain detectable viral RNA despite a negative rhino-pharyngeal swab. This finding, together with an intestinal expression of angiotensin conversion enzyme 2 protein, suggests a possible fecal-oral transmission for SARS-CoV-2. Furthermore, gastrointestinal (GI) symptoms are common in COVID-19 patients including watery diarrhea, vomiting-particularly in children-nausea, and abdominal pain. Pathogenesis of SARS-CoV-2 infection presents significant similarities to those of some immune-mediated diseases, such as inflammatory bowel diseases or rheumatoid arthritis, leading to the hypothesis that targeted therapies used for the treatment of immune-mediated disease could be effective to treat (and possibly prevent) the main complications of COVID-19. In this review, we synthesize the present and future impact of SARS-CoV-2 infection on the gastrointestinal system and on gastroenterology practice, hypothesizing a potential role of the "gut-lung axis" and perhaps of the gut and lung microbiota into the interindividual differential susceptibility to COVID-19 19 disease. Finally, we speculate on the reorganization of outpatient gastroenterology services, which need to consider, among other factors, the major psychological impact of strict lockdown measures on the whole population.

Cannabinoid receptor 2 agonist promotes parameters implicated in mucosal healing in patients with inflammatory bowel disease

BACKGROUND

Cannabis benefits patients with inflammatory bowel disease (IBD). Cannabinoid receptors are expressed in gut immune cells and in epithelial cells of inflamed guts. Mucosal healing (MH) requires epithelial layer restoration.

OBJECTIVE

To analyze the effects of CB2 agonist on parameters implicated in gut inflammation and MH.

METHODS

Mucosal samples from areas of inflamed/uninflamed colon from 16 patients with IBD were cultured without/with cannabinoid receptor 2 (CB2) agonist (JWH-133, 10 µM, 6 hours (hr)), and analyzed for epithelial/stromal cell proliferation, apoptosis (secretome matrix metalloproteinase 9 (MMP9) activity, which impairs epithelial permeability) and interleukin-8 (IL-8) levels (n = 5-9). In addition, Caco-2 (colon carcinoma epithelial cells) were cultured with biopsy secretomes (48 hr), and analyzed for phenotype and protein markers of proliferation (proliferating cell nuclear antigen), autophagy (LC3IIB) and permeability (Zonula occludens-1) (n = 4-6).

RESULTS

Uninflamed tissue had higher epithelial proliferation (Ki67: 50%↑, p < 0.05), and reduced secretome MMP9 activity and IL-8 levels (>50%↓, p < 0.05) compared to inflamed tissue. Treatment with CB2 agonist had no effect on epithelial apoptosis, but increased epithelial Ki67 expression (25%), and reduced secretome MMP9 and IL-8 levels in inflamed biopsies. Secretomes of CB2-treated biopsies increased Caco-2 number, migration, proliferating cell nuclear antigen and LC3IIB expression (all, p < 0.05), but had no effect on ZO-1.

CONCLUSION

Using ex vivo and in vitro human models, we demonstrated that manipulating the cannabinoid system affects colon cells and secretome characteristics that facilitate MH in IBD.

Bloating in Irritable Bowel Syndrome Is Associated with Symptoms Severity, Psychological Factors, and Comorbidities

BACKGROUND

Bloating is one of the most bothersome symptoms of irritable bowel syndrome (IBS), but its association with other symptoms is not well described.

AIMS

We investigated the association between symptoms of abdominal bloating, other IBS symptoms, psychological distress, and comorbid pain conditions.

METHODS

We conducted a cross-sectional study on a large cohort of IBS patients with and without symptoms of abdominal bloating and healthy controls. Subjects were assessed for IBS and its subtypes, pain severity, symptoms severity, psychological disturbances, comorbidities, and dietary restrictions of three fluid groups.

RESULTS

A total of 484 subjects were investigated. Compared with IBS - B, IBS + B subjects had higher rates of constipation (30% vs. 15%, p = 0.191) and lower rates of diarrhea, (70% vs. 85%, p = 0.191) although these were not statistically significant. Bloating severity correlated with IBS symptoms severity (r = 0.397, p = 0.000), pain severity (r = 0.364, p = 0.000), and both anxiety and somatization scores (r = 0.167, p = 0.015 and r = 0.219, p = 0.001, respectively). Prevalence of fibromyalgia and depression and somatization scores was significantly higher in IBS with bloating than in IBS without bloating. IBS patients with bloating reported more dietary restriction of three fluid groups to control their symptoms compared with healthy controls and IBS patients without bloating.

CONCLUSIONS

Abdominal bloating in IBS is associated with increased symptoms and pain severity, somatization, depression, fibromyalgia, and altered dietary fluids composition. Recognizing and addressing these factors in the diagnosis and management of patients with IBS may improve clinical outcome.

Endoscopic findings and esophageal cancer incidence among Fanconi Anemia patients participating in an endoscopic surveillance program

BACKGROUND AND AIMS

The primary clinical characteristics of Fanconi Anemia (FA) include typical physical features, progressive bone marrow failure, and an increased incidence of neoplasms, including esophageal carcinoma. Currently, there are no data regarding endoscopic findings or the interval time to malignancy in these patients. Data about the contribution of Human Papilloma Virus (HPV) to esophageal carcinoma is conflicting. Our objective is to document the upper gastrointestinal (GI) findings at baseline, document cancer incidence, and evaluate the role of HPV among these cancers.

METHODS

We reviewed endoscopic and clinical data of FA subjects who participated in active surveillance before cancer diagnosis. Incident esophageal cancers were stained for HPV ^p16 protein.

RESULTS

Eight FA patients were included (men 62.5%; median age at first endoscopy 20 years, median endoscopies number: 5.5). At baseline, 8/8 had endoscopic evidence for reflux esophagitis. In 3/8 the reflux esophagitis was mild and in 5/8 it was moderate or severe. During the follow up time (median time 4.5 years 2/8 developed Barrett's esophagus and 2/8 patients had incident esophageal squamous cell carcinoma during follow up, at intervals of eight and eighteen months from the previous upper endoscopy. Both cancers stained negative for HPV ^P16.

CONCLUSIONS

FA subjects have both an extremely high risk for esophageal cancer within short intervals and a very high prevalence of reflux esophagitis with various severities. Active surveillance programs in specialized centers including annual upper endoscopies should be considered in these patients.

Fecal and Mucosa-Associated Intestinal Microbiota in Patients with Diarrhea-Predominant Irritable Bowel Syndrome

BACKGROUND

Irritable bowel syndrome (IBS) has been associated with changes in the intestinal microbiota. Only a few studies have explored differences in the mucosa-associated microbiota between IBS patients and healthy controls (HC).

AIMS

To characterize and compare the microbiota in mucosal and fecal samples from carefully selected patients with IBS-D and HC.

METHODS

The cohort was composed of 23 diarrhea-predominant IBS (IBS-D) patients and 24 HC. Fresh stool samples were collected from participants prior to the collection of colonic mucosal samples from an unprepped bowel. After DNA extraction, 16S rRNA genes were sequenced by 454 pyrosequencing and analyzed using the QIIME pipeline.

RESULTS

The fecal microbiota (luminal niche) of IBS-D patients was found to have reduced enteric richness compared to HC (P < 0.05), whereas no differences were observed between the two groups within the mucosal microbiota. Within the luminal niche, the relative proportions of Faecalibacterium genus were found to be lower in IBS-D than in HC and the Dorea genus was higher in IBS-D. None of the taxa proportions were significantly different in IBS-D patients versus HC using an FDR of ≤ 0.1 when analyzing samples that appeared in > 25% samples of either niche.

CONCLUSION

Fecal and mucosal microbiota of IBS-D patients and HC are very similar and are not sufficient to explain the reported altered physiology and symptomatology of IBS-D. Future studies should investigate intestinal microbiome-dependent functional activity in addition to the fecal and mucosal-associated microbial composition.

Editorial: Clinical Implications of Diagnosing Irritable Bowel Syndrome: Do All Roads Need to Lead to Rome?

Irritable bowel syndrome (IBS) is one of the most common diagnoses made by healthcare providers. Yet the majority of patients with IBS are undiagnosed. The study by Sayuk et al. allows insight into the characteristics of different patient groups, e.g., with and without a formal diagnosis of diarrhea predominant IBS (IBS-D). We discuss the questions raised by this study regarding the importance of making a confident diagnosis, conveying it to patients and their implications for clinical practice.

The Gut Microbiome in Irritable Bowel Syndrome and Other Functional Bowel Disorders

Emerging data from epidemiologic, microbiome, and physiology research in patients with functional bowel disorders (FBDs) provide evidence for a linkage between alterations in the intestinal microbiota and FBDs. However, currently most of the data is based on association studies, and the causality role of the microbiota in these disorders is not established. Growing evidence for compositional changes and the increasing recognition of the association between the intestinal microbiota and gut-brain functions that are relevant to the pathophysiology and/or clinical symptoms of FBDs have led to increased interest in manipulating the intestinal microbiota for the treatment of these disorders.

Discordant temporal development of bacterial phyla and the emergence of core in the fecal microbiota of young children

The colonization pattern of intestinal microbiota during childhood may impact health later in life, but children older than 1 year are poorly studied. We followed healthy children aged 1-4 years (n=28) for up to 12 months, during which a synbiotic intervention and occasional antibiotics intake occurred, and compared them with adults from the same region. Microbiota was quantified with the HITChip phylogenetic microarray and analyzed with linear mixed effects model and other statistical approaches. Synbiotic administration increased the stability of Actinobacteria and antibiotics decreased Clostridium cluster XIVa abundance. Bacterial diversity did not increase in 1- to 5-year-old children and remained significantly lower than in adults. Actinobacteria, Bacilli and Clostridium cluster IV retained child-like abundances, whereas some other groups were converting to adult-like profiles. Microbiota stability increased, with Bacteroidetes being the main contributor. The common core of microbiota in children increased with age from 18 to 25 highly abundant genus-level taxa, including several butyrate-producing organisms, and developed toward an adult-like composition. In conclusion, intestinal microbiota is not established before 5 years of age and diversity, core microbiota and different taxa are still developing toward adult-type configuration. Discordant development patterns of bacterial phyla may reflect physiological development steps in children.

Molecular characterization of the intestinal microbiota in patients with and without abdominal bloating

Recent studies have demonstrated differences in the intestinal microbiota between patients with irritable bowel syndrome (IBS) and healthy controls (HC), suggesting a role for the intestinal microbiota in the pathogenesis of IBS. Alterations in the microbiota have also been implicated in the pathogenesis of abdominal bloating, a commonly reported symptom in IBS. We investigated the relationship between the intestinal microbiota, abdominal bloating, and altered bowel patterns in a cohort of patients with IBS and HC. The 16S rRNA gene from fresh fecal samples was amplified and pyrosequenced by using Roche-454 Titanium chemistry. A Core Measurable Microbiome (CMM) was generated for Operational Taxonomic Unit (OTU) detected in >75% of all samples and compositional features of CMM were compared between groups by Linear Discriminant Analysis (LDA). IBS differentiated from HC by LDA using continuous variation in the species/OTUs or the CMM genera. When subcategorized based on bloating symptoms and bowel characteristics, the same subjects were also well differentiated from one another and from HC. ANOVA analysis showed quantitative species/OTU differences between the subgroups including IBS with and without bloating, and subtypes based on bowel characteristics. The clear LDA differentiation and the significant microbial taxa differences between the groups imply a significant association of the microbiota with bloating symptoms and bowel characteristics in IBS. These changes in the microbiota may serve as a biomarker for IBS and its clinical subtypes and suggest a role for the intestinal microbiota in the pathogenesis of the main symptoms of the disorder.

Use of probiotics in prevention and treatment of patients with Clostridium difficile infection

Clostridium difficile is an anaerobic, gram positive, sporulating, toxin-producing bacillus which causes a spectrum of clinical disease ranging from an asymptomatic carrier state to toxic megacolon and fulminant disease. Infection with C. difficile is an expensive and pervasive health care burden. The current theory regarding the development of C. difficile infection (CDI) suggests that disruption of the structure and/or function of an individual's normal intestinal microbiota enables colonization by C. difficile, and in the absence of an effective immune response, the bacteria causes illness. In this article we discuss the role of the colonic microbiota in the development of CDI and the potential role of probiotics in preventing and treating CDI. We review the evidence from in vitro laboratory and pre-clinical studies, as well as evidence from clinical studies and discuss the current recommendations for the use of probiotics for CDI in clinical practice.

Probiotics in functional bowel disorders

Functional bowel disorders (FBDs) are the most common gastrointestinal (GI) disorders seen by gastroenterologists and primary care physicians. The disorders affect patients functioning and quality of life (QOL) and are associated with significant healthcare burden. The current theory regarding the development of FBDs suggests brain-gut axis dysfunctions associated abnormal GI motility and sensation. Recent data suggest that alterations in the intestinal microbiota may have a role in the pathogenesis of FBDs; or at least have the potential to affect intestinal functions that are thought to be relevant to the development of functional GI symptoms. This has led to growing interest of healthcare providers and patients in targeting the intestinal microbiota for the treatment of FBDs. In this article we discuss the potential role probiotic interventions in the treatment of FBDs. We review the evidence from pre-clinical and clinical studies and discuss the current recommendations for the use of probiotics for FBDs in clinical practice.

Altered Colonic Bacterial Fermentation as a Potential Pathophysiological Factor in Irritable Bowel Syndrome

OBJECTIVES

Dysbiosis leading to abnormal intestinal fermentation has been suggested as a possible etiological mechanism in irritable bowel syndrome (IBS). We aimed to investigate the location and magnitude of altered intestinal bacterial fermentation in IBS and its clinical subtypes.

METHODS

IBS patients who satisfied the Rome III criteria (114) and 33 healthy controls (HC) were investigated. Intestinal fermentation was assessed using two surrogate measures: intestinal intraluminal pH and fecal short-chain fatty acids (SCFAs). Intraluminal pH and intestinal transit times were measured in the small and large bowel using a wireless motility capsule (SmartPill) in 47 IBS and 10 HC. Fecal SCFAs including acetate, propionate, butyrate, and lactate were analyzed by capillary gas chromatography in all enrolled subjects. Correlations between intestinal pH, fecal SCFAs, intestinal transit time, and IBS symptom scores were analyzed.

RESULTS

Colonic intraluminal pH levels were significantly lower in IBS patients compared with HC (total colonic pH, 6.8 for IBS vs. 7.3 for HC, P=0.042). There were no differences in total and segmental pH levels in the small bowel between IBS patients and HC (6.8 vs. 6.8, P=not significant). The intraluminal colonic pH differences were consistent in all IBS subtypes. Total SCFA level was significantly lower in C-IBS patients than in D-IBS and M-IBS patients and HC. The total SCFA level in all IBS subjects was similar with that of HC. Colonic pH levels correlated positively with colon transit time (CTT) and IBS symptoms severity. Total fecal SCFAs levels correlated negatively with CTT and positively with stool frequency.

CONCLUSIONS

Colonic intraluminal pH is decreased, suggesting higher colonic fermentation, in IBS patients compared with HC. Fecal SCFAs are not a sensitive marker to estimate intraluminal bacterial fermentation.

High throughput sequencing reveals distinct microbial populations within the mucosal and luminal niches in healthy individuals

BACKGROUND

The intestinal microbiota is associated with human health and diseases. The luminal microbiota (LM) and the mucosal-associated microbiota (MAM) are 2 distinct ecosystems with different metabolic and immunological functions.

AIM

To characterize the intestinal LM and MAM in humans using high throughput sequencing of the 16S rRNA gene.

METHODS

Fresh fecal samples and distal colonic mucosal biopsies collected from 24 healthy subjects before (fecal) and during (mucosa) a flexible sigmoidoscopy of an un-prepared bowel. High throughput sequencing of the 16S rRNA gene was used to characterize bacterial communities. Sequences were processed using the QIIME pipeline.

RESULTS

LM and MAM populations were significantly different (ANOSIM: R = 0.49, P = 0.001). The LM displayed tighter clustering compared to the MAM (average weighted UniFrac distances 0.27 ± 0.05 vs. 0.43 ± 0.09, P < 0.001, respectively), and showed higher diversity (Shannon diversity index: 4.96 ± 0.37 vs 4.14 ± 0.56, respectively, P < 0.001). The dominant phyla in the LM and MAM were significantly different: Firmicutes (41.4% vs. 29.1%, FDR < 0.0001, respectively), Bacteroidetes (20.2% vs. 26.3%, FDR < 0.05, respectively), Actinobacteria (22% vs. 12.6%, FDR < 0.0001, respectively) and Proteobacteria (9.3% vs. 19.3%, FDR < 0.0001, respectively). The abundance of 56 genera differed significantly (FDR < 0.1) between the 2 niches. All of the genera in the fecal microbiota were present in the MAM while 10 genera were found to be unique to the MAM.

CONCLUSION

The LM and MAM are distinct microbial ecosystems that differ significantly from each other in microbial diversity and composition. These two microbial niches should be investigated independently to better understand the role of the intestinal microbiota in health and disease.

Lactobacillus acidophilus NCFM affects colonic mucosal opioid receptor expression in patients with functional abdominal pain - a randomised clinical study

BACKGROUND

In a recent double-blinded clinical trial, the probiotic combination of Lactobacillus acidophilus NCFM (L-NCFM) and B-LBi07 reduced bloating symptoms in patients with functional bowel disorders; an effect more evident in those who reported abdominal pain. In mice, L-NCFM but not B-LBi07 induced colonic mu-opioid receptor (MOR) and cannabinoid receptor 2 (CB2) expression, and reduced visceral sensitivity.

AIMS

To determine if L-NCFM was the active component in the clinical trial and to investigate the mechanism of action in humans with mild to moderate abdominal pain.

METHODS

Caucasian women (n = 20) 18-70 years with mild to moderate abdominal pain were enrolled in a double-blind, two-armed, single-centre study. Patients were given either L-NCFM alone or in combination with B-LBi07 for 21 days at a total dose of 2 × 10(10) CFU b.d. Colonic biopsies were collected during unsedated, unprepped flexible sigmoidoscopy before and at the end of probiotic consumption. mRNA and immunostaining were then performed on these biopsies. Patients kept symptom diaries for the 7 days prior to starting probiotic therapy and for the last 7 days of therapy.

RESULTS

L-NCFM alone, but not with B-LBi07, induced colonic MOR mRNA and protein expression, as well as downstream signalling, as measured by enterocyte STAT3-phosphorylation. In contrast, CB2 expression was decreased. Both treatment groups trended towards improvement in symptoms, but the study was insufficiently powered to draw meaningful conclusions.

CONCLUSIONS

Lactobacillus acidophilus NCFM modulates mu-opioid receptor expression and activity, while the combination of L-NCFM and B-LBi07 does not. This study provides a possible mechanism for action by which probiotics modulates pain sensation in humans (Clinical Trial Number: NCT01064661).

Is ginger effective for the treatment of irritable bowel syndrome? A double blind randomized controlled pilot trial

OBJECTIVES

Ginger is one of the most commonly used herbal medicines for irritable bowel syndrome (IBS) but no data exists about its effectiveness.

DESIGN

Double blind randomized controlled trial.

SETTING

University of North Carolina, Chapel Hill, North Carolina, USA.

INTERVENTION

Forty-five IBS patients were randomly assigned to three groups: placebo, 1g of ginger, and 2g of ginger daily for 28 days.

MAIN OUTCOME MEASURES

The IBS severity scale (IBS-SS) was administered, as well as adequate relief of symptoms scale. A responder was defined as having at least 25% reduction in IBS-SS post-treatment.

RESULTS

There were 57.1% responders to placebo, 46.7% to 1g and 33.3% to 2g of ginger. Adequate relief was reported by 53.3% on placebo and 53.3% in both ginger groups combined. Side effects were mild and reported by 35.7% in the placebo and 16.7% in the ginger groups.

CONCLUSIONS

This double blind randomized controlled pilot study suggests ginger is well tolerated but did not perform better than placebo. Larger trials are needed before any definitive conclusions can be drawn.

Fecal protease activity is associated with compositional alterations in the intestinal microbiota

Objective

Intestinal proteases carry out a variety of functions in the gastrointestinal (GI) tract. Studies have reported that elevated enteric proteases in patients with GI disease can alter intestinal physiology, however the origin (human vs. microbial) of elevated proteases in patients with GI disease is unclear.

Aim

The aim of this study was to investigate the association between protease activity and the microbiota in human fecal samples.

Design

In order to capture a wide range of fecal protease (FP) activity stool samples were collected from 30 IBS patients and 24 healthy controls. The intestinal microbiota was characterized using 454 high throughput pyro-sequencing of the 16S rRNA gene. The composition and diversity of microbial communities were determined and compared using the Quantitative Insights Into Microbial Ecology (QIIME) pipeline. FP activity levels were determined using an ELISA-based method. FP activity was ranked and top and bottom quartiles (n=13 per quartile) were identified as having high and low FP activity, respectively.

Results

The overall diversity of the intestinal microbiota displayed significant clustering separation (p = 0.001) between samples with high vs. low FP activity. The Lactobacillales, Lachnospiraceae, and Streptococcaceae groups were positively associated with FP activity across the entire study population, whilst the Ruminococcaceae family and an unclassified Coriobacteriales family were negatively associated with FP activity.

Conclusions

These data demonstrate significant associations between specific intestinal bacterial groups and fecal protease activity and provide a basis for further causative studies investigating the role of enteric microbes and GI diseases.

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

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

Intestinal microbiota in healthy U.S. young children and adults--a high throughput microarray analysis

It is generally believed that the infant's microbiota is established during the first 1–2 years of life. However, there is scarce data on its characterization and its comparison to the adult-like microbiota in consecutive years.

Aim

To characterize and compare the intestinal microbiota in healthy young children (1–4 years) and healthy adults from the North Carolina region in the U.S. using high-throughput bacterial phylogenetic microarray analysis.

Methods

Detailed characterization and comparison of the intestinal microbiota of healthy children aged 1–4 years old (n = 28) and healthy adults of 21–60 years (n = 23) was carried out using the Human Intestinal Tract Chip (HITChip) phylogenetic microarray targeting the V1 and V6 regions of 16S rRNA and quantitative PCR.

Results

The HITChip microarray data indicate that Actinobacteria, Bacilli, Clostridium cluster IV and Bacteroidetes are the predominant phylum-like groups that exhibit differences between young children and adults. The phylum-like group Clostridium cluster XIVa was equally predominant in young children and adults and is thus considered to be established at an early age. The genus-like level show significant 3.6 fold (higher or lower) differences in the abundance of 26 genera between young children and adults. Young U.S. children have a significantly 3.5-fold higher abundance of Bifidobacterium species than the adults from the same location. However, the microbiota of young children is less diverse than that of adults.

Conclusions

We show that the establishment of an adult-like intestinal microbiota occurs at a later age than previously reported. Characterizing the microbiota and its development in the early years of life may help identify ‘windows of opportunity’ for interventional strategies that may promote health and prevent or mitigate disease processes.

The intestinal microbiome, probiotics and prebiotics in neurogastroenterology

The brain-gut axis allows bidirectional communication between the central nervous system (CNS) and the enteric nervous system (ENS), linking emotional and cognitive centers of the brain with peripheral intestinal functions. Recent experimental work suggests that the gut microbiota have an impact on the brain-gut axis. A group of experts convened by the International Scientific Association for Probiotics and Prebiotics (ISAPP) discussed the role of gut bacteria on brain functions and the implications for probiotic and prebiotic science. The experts reviewed and discussed current available data on the role of gut microbiota on epithelial cell function, gastrointestinal motility, visceral sensitivity, perception and behavior. Data, mostly gathered from animal studies, suggest interactions of gut microbiota not only with the enteric nervous system but also with the central nervous system via neural, neuroendocrine, neuroimmune and humoral links. Microbial colonization impacts mammalian brain development in early life and subsequent adult behavior. These findings provide novel insights for improved understanding of the potential role of gut microbial communities on psychological disorders, most particularly in the field of psychological comorbidities associated with functional bowel disorders like irritable bowel syndrome (IBS) and should present new opportunity for interventions with pro- and prebiotics.

Burden of gastrointestinal disease in the United States: 2012 update

BACKGROUND & AIMS

Gastrointestinal (GI) diseases account for substantial morbidity, mortality, and cost. Statistical analyses of the most recent data are necessary to guide GI research, education, and clinical practice. We estimate the burden of GI disease in the United States.

METHODS

We collected information on the epidemiology of GI diseases (including cancers) and symptoms, along with data on resource utilization, quality of life, impairments to work and activity, morbidity, and mortality. These data were obtained from the National Ambulatory Medical Care Survey; National Health and Wellness Survey; Nationwide Inpatient Sample; Surveillance, Epidemiology, and End Results Program; National Vital Statistics System; Thompson Reuters MarketScan; Medicare; Medicaid; and the Clinical Outcomes Research Initiative's National Endoscopic Database. We estimated endoscopic use and costs and examined trends in endoscopic procedure.

RESULTS

Abdominal pain was the most common GI symptom that prompted a clinic visit (15.9 million visits). Gastroesophageal reflux was the most common GI diagnosis (8.9 million visits). Hospitalizations and mortality from Clostridium difficile infection have doubled in the last 10 years. Acute pancreatitis was the most common reason for hospitalization (274,119 discharges). Colorectal cancer accounted for more than half of all GI cancers and was the leading cause of GI-related mortality (52,394 deaths). There were 6.9 million upper, 11.5 million lower, and 228,000 biliary endoscopies performed in 2009. The total cost for outpatient GI endoscopy examinations was $32.4 billion.

CONCLUSIONS

GI diseases are a source of substantial morbidity, mortality, and cost in the United States.

Characterization of the fecal microbiota using high-throughput sequencing reveals a stable microbial community during storage

The handling and treatment of biological samples is critical when characterizing the composition of the intestinal microbiota between different ecological niches or diseases. Specifically, exposure of fecal samples to room temperature or long term storage in deep freezing conditions may alter the composition of the microbiota. Thus, we stored fecal samples at room temperature and monitored the stability of the microbiota over twenty four hours. We also investigated the stability of the microbiota in fecal samples during a six month storage period at -80°C. As the stability of the fecal microbiota may be affected by intestinal disease, we analyzed two healthy controls and two patients with irritable bowel syndrome (IBS). We used high-throughput pyrosequencing of the 16S rRNA gene to characterize the microbiota in fecal samples stored at room temperature or -80°C at six and seven time points, respectively. The composition of microbial communities in IBS patients and healthy controls were determined and compared using the Quantitative Insights Into Microbial Ecology (QIIME) pipeline. The composition of the microbiota in fecal samples stored for different lengths of time at room temperature or -80°C clustered strongly based on the host each sample originated from. Our data demonstrates that fecal samples exposed to room or deep freezing temperatures for up to twenty four hours and six months, respectively, exhibit a microbial composition and diversity that shares more identity with its host of origin than any other sample.

Treatment of functional diarrhea

Functional diarrhea (FD), one of the functional gastrointestinal disorders, is characterized by chronic or recurrent diarrhea not explained by structural or biochemical abnormalities. The treatment of FD is intimately associated with establishing the correct diagnosis. First, FD needs to be distinguished from diarrhea-predominant irritable bowel syndrome (IBS), in which, unlike in FD, abdominal pain is a primary diagnostic criterion. Next, FD must be differentiated from the myriad organic causes of chronic diarrhea. Unlike IBS, in which a positive diagnosis can be made with an acceptable level of confidence using symptom-based criteria and minimal testing, the diagnosis of FD is still primarily a diagnosis of exclusion. Thus, the onus is on the physician to eliminate potential underlying causes, both common and uncommon, in the proper clinical setting. Once the diagnosis has been established, the clinician and patient should first focus on identifying, eliminating, and/or treating aggravating factors. These may include physiologic factors (eg, small bowel bacterial overgrowth), psychological factors (eg, stress and anxiety), and dietary factors (eg, carbohydrate malabsorption). Thereafter, appropriate treatment for functional diarrhea may be instituted. Treatment options include dietary and lifestyle modification, pharmacologic therapies, and alternative modalities. Although many of these strategies have been studied in IBS, almost none of them has been examined specifically in FD. Furthermore, given the poorly understood pathophysiologic basis of FD, these treatments primarily target a patient's symptoms and presumed altered physiology rather than underlying etiologic mechanisms. Therefore, we stress that treatment must be approached in an individualized manner and that dietary and pharmacologic therapies should be part of a comprehensive therapeutic approach in which education and reassurance form the foundation. In general, we attempt to remove dietary triggers and recommend increased fiber intake. We then add anticholinergic, antispasmodic, antimotility, and antidiarrheal agents as the first line of pharmacotherapy. Should a patient not respond to these, and for patients who have a significant degree of psychological dysfunction, central acting agents, including antidepressants and/or anxiolytics, may be beneficial. During the treatment period, we also recommend that physicians keep an open mind. If signs or symptoms that suggest an ongoing or previously unrecognized organic process develop, then a re-evaluation of the clinical picture is indicated.

Alterations in composition and diversity of the intestinal microbiota in patients with diarrhea-predominant irritable bowel syndrome

BACKGROUND

The intestinal microbiota has been implicated in the pathophysiology of irritable bowel syndrome (IBS). Due to the variable resolutions of techniques used to characterize the intestinal microbiota, and the heterogeneity of IBS, the defined alterations of the IBS intestinal microbiota are inconsistent. We analyzed the composition of the intestinal microbiota in a defined subgroup of IBS patients (diarrhea-predominant IBS, D-IBS) using a technique that provides the deepest characterization available for complex microbial communities.

METHODS

Fecal DNA was isolated from 23 D-IBS patients and 23 healthy controls (HC). Variable regions V1-V3 and V6 of the 16S rRNA gene were amplified from all samples. PCR products were sequenced using 454 high throughput sequencing. The composition, diversity and richness of microbial communities were determined and compared between D-IBS and HC using the quantitative insights into microbial ecology pipeline.

KEY RESULTS

The contribution of bacterial groups to the composition of the intestinal microbiota differed between D-IBS and HC. D-IBS patients had significantly higher levels of Enterobacteriaceae (P = 0.03), and lower levels of Fecalibacterium genera (P = 0.04) compared to HC. β-Diversity values demonstrated significantly lower levels of UniFrac distances in HC compared to D-IBS patients. The richness of 16S rRNA sequences was significantly decreased in D-IBS patients (P < 0.04).

CONCLUSIONS & INFERENCES

Our 16S rRNA sequence data demonstrates a community-level dysbiosis in D-IBS. The altered composition of the intestinal microbiota in D-IBS is associated with significant increases in detrimental and decreases in beneficial bacterial groups, and a reduction in microbial richness.

Prebiotics and the health benefits of fiber: current regulatory status, future research, and goals

First defined in the mid-1990s, prebiotics, which alter the composition and activity of gastrointestinal (GI) microbiota to improve health and well-being, have generated scientific and consumer interest and regulatory debate. The Life Sciences Research Organization, Inc. (LSRO) held a workshop, Prebiotics and the Health Benefits of Fiber: Future Research and Goals, in February 2011 to assess the current state of the science and the international regulatory environment for prebiotics, identify research gaps, and create a strategy for future research. A developing body of evidence supports a role for prebiotics in reducing the risk and severity of GI infection and inflammation, including diarrhea, inflammatory bowel disease, and ulcerative colitis as well as bowel function disorders, including irritable bowel syndrome. Prebiotics also increase the bioavailability and uptake of minerals and data suggest that they reduce the risk of obesity by promoting satiety and weight loss. Additional research is needed to define the relationship between the consumption of different prebiotics and improvement of human health. New information derived from the characterization of the composition and function of different prebiotics as well as the interactions among and between gut microbiota and the human host would improve our understanding of the effects of prebiotics on health and disease and could assist in surmounting regulatory issues related to prebiotic use.

Anti-enteric neuronal antibodies and the irritable bowel syndrome

Background/Aims

Functional gastrointestinal disorders are those in which no abnormal metabolic or physical processes, which can account for the symptoms, can be identified. The irritable bowel syndrome (IBS) is a significant functional disorder, which affects 10-20 percent of the population worldwide. Predominant symptoms of IBS are abnormal defecation associated with abdominal pain, both of which may be exacerbated by psychogenic stress. Our study was designed to test a hypothesis that symptoms in a subset of patients with a diagnosis of IBS are associated with an autoimmune degenerative neuropathy in the enteric nervous system.

Methods

Serum was collected from Rome II-IBS patients and controls at the University of North Carolina Functional Gastrointestinal Diseases Center. Assay procedures were immunohistochemical localization of antibody binding to enteric neurons and human protein microarray assay for antigens recognized by antibodies in the sera.

Results

Eighty-seven percent of IBS sera and 59% of control sera contained anti-enteric neuronal antibodies. Antibody immunostaining was seen in the nucleus and cytoplasm of neurons in the enteric nervous system. Protein microarray analysis detected antibody reactivity for autoantigens in serum with anti-enteric neuronal antibodies and no reactivity for the same autoantigens in samples not containing anti-enteric neuronal antibodies in our immunostaining assay. Antibodies in sera from IBS patients recognized only 3 antigens out of an 8,000 immunoprotein array. The 3 antigens were: (1) a nondescript ribonucleoprotein (RNP-complex); (2) small nuclear ribonuclear polypeptide A; and (3) Ro-5,200 kDa.

Conclusions

Results of the present study suggest that symptoms in a subset of IBS patients might be a reflection of enteric neuronal damage or loss, caused by circulating anti-enteric autoimmune antibodies.

Molecular analysis of the luminal- and mucosal-associated intestinal microbiota in diarrhea-predominant irritable bowel syndrome

Alterations in the intestinal microbiota have been suggested as an etiological factor in the pathogenesis of irritable bowel syndrome (IBS). This study used a molecular fingerprinting technique to compare the composition and biodiversity of the microbiota within fecal and mucosal niches between patients with diarrhea-predominant IBS (D-IBS) and healthy controls. Terminal-restriction fragment (T-RF) length polymorphism (T-RFLP) fingerprinting of the bacterial 16S rRNA gene was used to perform microbial community composition analyses on fecal and mucosal samples from patients with D-IBS (n = 16) and healthy controls (n = 21). Molecular fingerprinting of the microbiota from fecal and colonic mucosal samples revealed differences in the contribution of T-RFs to the microbiota between D-IBS patients and healthy controls. Further analysis revealed a significantly lower (1.2-fold) biodiversity of microbes within fecal samples from D-IBS patients than healthy controls (P = 0.008). No difference in biodiversity in mucosal samples was detected between D-IBS patients and healthy controls. Multivariate analysis of T-RFLP profiles demonstrated distinct microbial communities between luminal and mucosal niches in all samples. Our findings of compositional differences in the luminal- and mucosal-associated microbiota between D-IBS patients and healthy controls and diminished microbial biodiversity in D-IBS fecal samples further support the hypothesis that alterations in the intestinal microbiota may have an etiological role in the pathogenesis of D-IBS and suggest that luminal and mucosal niches need to be investigated.

Rifaximin therapy for patients with irritable bowel syndrome without constipation

BACKGROUND

Evidence suggests that gut flora may play an important role in the pathophysiology of the irritable bowel syndrome (IBS). We evaluated rifaximin, a minimally absorbed antibiotic, as treatment for IBS.

METHODS

In two identically designed, phase 3, double-blind, placebo-controlled trials (TARGET 1 and TARGET 2), patients who had IBS without constipation were randomly assigned to either rifaximin at a dose of 550 mg or placebo, three times daily for 2 weeks, and were followed for an additional 10 weeks. The primary end point, the proportion of patients who had adequate relief of global IBS symptoms, and the key secondary end point, the proportion of patients who had adequate relief of IBS-related bloating, were assessed weekly. Adequate relief was defined as self-reported relief of symptoms for at least 2 of the first 4 weeks after treatment. Other secondary end points included the percentage of patients who had a response to treatment as assessed by daily self-ratings of global IBS symptoms and individual symptoms of bloating, abdominal pain, and stool consistency during the 4 weeks after treatment and during the entire 3 months of the study.

RESULTS

Significantly more patients in the rifaximin group than in the placebo group had adequate relief of global IBS symptoms during the first 4 weeks after treatment (40.8% vs. 31.2%, P=0.01, in TARGET 1; 40.6% vs. 32.2%, P=0.03, in TARGET 2; 40.7% vs. 31.7%, P<0.001, in the two studies combined). Similarly, more patients in the rifaximin group than in the placebo group had adequate relief of bloating (39.5% vs. 28.7%, P=0.005, in TARGET 1; 41.0% vs. 31.9%, P=0.02, in TARGET 2; 40.2% vs. 30.3%, P<0.001, in the two studies combined). In addition, significantly more patients in the rifaximin group had a response to treatment as assessed by daily ratings of IBS symptoms, bloating, abdominal pain, and stool consistency. The incidence of adverse events was similar in the two groups.

CONCLUSIONS

Among patients who had IBS without constipation, treatment with rifaximin for 2 weeks provided significant relief of IBS symptoms, bloating, abdominal pain, and loose or watery stools. (Funded by Salix Pharmaceuticals; ClinicalTrials.gov numbers, NCT00731679 and NCT00724126.).

Luminal and mucosal-associated intestinal microbiota in patients with diarrhea-predominant irritable bowel syndrome

Background

Recent studies have suggested a role for an altered intestinal microbiota in the pathophysiology of irritable bowel syndrome (IBS). However, no consensus has been reached regarding the association between specific enteric bacterial groups and IBS. The aim of this study was to investigate the fecal and mucosal-associated microbiota using two independent techniques in intestinal samples from diarrhea-predominant IBS (D-IBS) and healthy controls.

Methods

Fecal and colonic mucosal biopsy samples were obtained from 10 D-IBS patients and 10 healthy controls. Colonic tissue was collected during a un-sedated un-prepped flexible sigmoidoscopy. Fecal and tissue samples were processed immediately upon collection for culture under aerobic and anaerobic conditions or frozen for further molecular analysis. DNA was extracted from all frozen samples and used to enumerate specific bacterial groups using quantitative real-time PCR (qPCR).

Results

Culture analysis of intestinal samples demonstrated a significant reduction in the concentration of aerobic bacteria in fecal samples from D-IBS patients when compared to healthy controls (1.4 × 10⁷ vs. 8.4 × 10⁸ CFUs/g feces, P = 0.002). qPCR analysis demonstrated a significant 3.6 fold increase (P = 0.02) in concentrations of fecal Lactobacillus species between D-IBS patients and healthy controls.

Conclusions

Our culture and molecular data indicate that quantitative differences exist in specific bacterial groups in the microbiota between D-IBS and healthy subjects.

Wireless pH-motility capsule for colonic transit: prospective comparison with radiopaque markers in chronic constipation

BACKGROUND

Colon transit (CT) measurements are used in the management of significant constipation. The radiopaque marker (ROM) method provides limited information.

METHODS

We proposed to validate wireless motility capsule (WMC), that measures pH, pressure and temperature, to ROM measurement of CT in patients with symptomatic constipation evaluated at multiple centers. Of 208 patients recruited, 158 eligible patients underwent simultaneous measurement of colonic transit time (CTT) using ROM (Metcalf method, cut off for delay >67 h), and WMC (cutoff for delay >59 h). The study was designed to demonstrate substantial equivalence, defined as diagnostic agreement >65% for patients who had normal or delayed ROM transit.

KEY RESULTS

Fifty-nine of 157 patients had delayed ROM CT. Transit results by the two methods differed: ROM median 55.0 h [IQR 31.0-85.0] and WMC (43.5 h [21.7-70.3], P < 0.001. The positive percent agreement between WMC and ROM for delayed transit was approximately 80%; positive agreement in 47 by WMC/59 by ROM or 0.796 (95% CI = 0.67-0.98); agreement vs null hypothesis (65%) P = 0.01. The negative percent agreement (normal transit) was approximately 91%: 89 by WMC/98 by ROM or 0.908 (95% CI = 0.83-0.96); agreement vs null hypothesis (65%), P = 0.00001. Overall device agreement was 87%. There were significant correlations (P < 0.001) between ROM and WMC transit (CTT [r = 0.707] and between ROM and combined small and large bowel transit [r = 0.704]). There were no significant adverse events.

CONCLUSIONS & INFERENCES

The 87% overall agreement (positive and negative) validates WMC relative to ROM in differentiating slow vs normal CT in a multicenter clinical study of constipation.

Alterations in the intestinal microbiota and functional bowel symptoms

Functional gastrointestinal disorders (FGIDs) are highly prevalent in Western countries yet no single mechanism or etiological agent that initiates IBS has been identified. Current research has implicated the intestinal microbiota with FGIDs. This article reviews the available literature/data regarding the intestinal microbiota and FGIDS. The possible relationships between the intestinal microbiota and the intestinal function and functional bowel symptoms are discussed.

Prevalence, characteristics, and impact of bloating symptoms in patients with irritable bowel syndrome

BACKGROUND & AIMS

Bloating symptoms are common in patients with irritable bowel syndrome (IBS) seen in primary care and gastrointestinal clinics. However, the underlying mechanisms of IBS are poorly understood, and there are few data available about the epidemiology of this syndrome or the impact of its symptoms. We investigated the prevalence, characteristics, and impact of bloating symptoms in patients with IBS.

METHODS

IBS patients were identified by Rome II criteria in a U.S. population representative web-based survey. Patients were asked about the quality, frequency, and severity of their gastrointestinal symptoms. The impact of these symptoms was investigated by assessing patients' health-related quality of life, utilization of health care, and use of medications.

RESULTS

Of the 337 IBS patients in this study, 82.5% (n = 278) reported bloating symptoms, the second most bothersome symptom after abdominal cramping. The symptoms were more prevalent in female patients, 87.4% (n = 209), than in male patients, 70.4% (n = 69) (P < .0001), and in patients with constipation, 88.7% (n = 47), and mixed symptoms, 88.8% (n = 135), than in patients with diarrhea, 72.3% (n = 96), (P = .02 and P < .01, respectively). Bloating symptoms were the third (of 14) most important reason to seek medical care, and more than half of the patients reported regular use of anti-gas medications. Bloating symptoms were associated with decreased energy levels (P = .04), food intake (P < .01), and physical functioning (P = .06).

CONCLUSIONS

Bloating symptoms are common in patients with IBS, and their prevalence and relative severity differ on the basis of sex and IBS subtype. Bloating symptoms are associated with a decrease in the quality of life and increases in health care utilization and use of medications.

Effect of abuse history on pain reports and brain responses to aversive visceral stimulation: an FMRI study

BACKGROUND & AIMS

Abuse history is common in irritable bowel syndrome (IBS) and is associated with greater pain reporting, psychologic distress, and poorer health outcome. These effects may be mediated by enhanced responses to aversive visceral stimuli. We investigated the effects of IBS and abuse history on pain reporting and brain activation in response to rectal distentions.

METHODS

Ten female patients with IBS and 10 controls were included. Half of patients in each group reported a history of abuse. Brain functional magnetic resonance imaging (fMRI) images and pain ratings were obtained during rectal distentions. Statistical parametric mapping identified activation in subregions of the dorsal cingulate cortex and covariation with rated pain.

RESULTS

(1) Distention-elicited pain correlated with anxiety and activation of the posterior (PCC) and middle (MCC) dorsal cingulate subregions. (2) Subjects with a history of abuse showed greater activation in the left MCC (P = .022; t = 5.61) and PCC (P = .033; t = 5.00) than subjects without abuse. (3) Those with IBS and abuse reported greater pain than all others (P = .004), had more activity in the left MCC (P = .021; t = 5.29) and PCC (P = .049; t = 4.81), and had less activity in the left supragenual anterior cingulate (sACC) (P = .01; t = 4.86).

CONCLUSIONS

Pain ratings during rectal distention are associated with activation of dorsal cingulate regions implicated in homeostatic afferent processing, and prior abuse enhances this activation. Patients with IBS and abuse report more pain, greater MCC/PCC activation, and reduced activity of a region implicated in pain inhibition and arousal (sACC). These findings suggest a possible explanation for the clinical observation of greater pain reporting and poorer outcome in IBS patients with a history of abuse.

Increased colonic pain sensitivity in irritable bowel syndrome is the result of an increased tendency to report pain rather than increased neurosensory sensitivity

OBJECTIVE

The aim was to determine whether lower visceral pain thresholds in irritable bowel syndrome (IBS) primarily reflect physiological or psychological factors.

METHODS

Firstly, 121 IBS patients and 28 controls underwent balloon distensions in the descending colon using the ascending methods of limits (AML) to assess pain and urge thresholds. Secondly, sensory decision theory analysis was used to separate physiological from psychological components of perception: neurosensory sensitivity (p(A)) was measured by the ability to discriminate between 30 mm Hg vs 34 mm Hg distensions; psychological influences were measured by the report criterion-that is, the overall tendency to report pain, indexed by the median intensity rating for all distensions, independent of intensity. Psychological symptoms were assessed using the Brief Symptom Inventory (BSI).

RESULTS

IBS patients had lower AML pain thresholds (median: 28 mm Hg vs 40 mm Hg; p<0.001), but similar neurosensory sensitivity (median p(A): 0.5 vs 0.5; p = 0.69; 42.6% vs 42.9% were able to discriminate between the stimuli better than chance) and a greater tendency to report pain (median report criterion: 4.0 ("mild" pain) vs 5.2 ("weak" pain); p = 0.003). AML pain thresholds were not correlated with neurosensory sensitivity (r = -0.13; p = 0.14), but were strongly correlated with report criterion (r = 0.67; p<0.0001). Report criterion was inversely correlated with BSI somatisation (r = -0.26; p = 0.001) and BSI global score (r = -0.18; p = 0.035). Similar results were seen for the non-painful sensation of urgency.

CONCLUSION

Increased colonic sensitivity in IBS is strongly influenced by a psychological tendency to report pain and urge rather than increased neurosensory sensitivity.

Randomized, controlled trial shows biofeedback to be superior to alternative treatments for patients with pelvic floor dyssynergia-type constipation

PURPOSE

This study was designed to determine whether biofeedback is more effective than diazepam or placebo in a randomized, controlled trial for patients with pelvic floor dyssynergia-type constipation, and whether instrumented biofeedback is necessary for successful training.

METHODS

A total of 117 patients participated in a four-week run-in (education and medical management). The 84 who remained constipated were randomized to biofeedback (n=30), diazepam (n=30), or placebo (n=24). All patients were trained to do pelvic floor muscle exercises to correct pelvic floor dyssynergia during six biweekly one-hour sessions, but only biofeedback patients received electromyography feedback. All other patients received pills one to two hours before attempting defecation. Diary data on cathartic use, straining, incomplete bowel movements, Bristol stool scores, and compliance with homework were reviewed biweekly.

RESULTS

Before treatment, the groups did not differ on demographic (average age, 50 years; 85 percent females), physiologic or psychologic characteristics, severity of constipation, or expectation of benefit. Biofeedback was superior to diazepam by intention-to-treat analysis (70 vs. 23 percent reported adequate relief of constipation 3 months after treatment, chi-squared=13.1, P<0.001), and also superior to placebo (38 percent successful, chi-squared=5.7, P=0.017). Biofeedback patients had significantly more unassisted bowel movements at follow-up compared with placebo (P=0.005), with a trend favoring biofeedback over diazepam (P=0.067). Biofeedback patients reduced pelvic floor electromyography during straining significantly more than diazepam patients (P<0.001).

CONCLUSIONS

This investigation provides definitive support for the efficacy of biofeedback for pelvic floor dyssynergia and shows that instrumented biofeedback is essential to successful treatment.

Low-dose naltreoxone for the treatment of irritable bowel syndrome: a pilot study

Preclinical studies have shown that a very low dose of naltreoxone hydrochloride (NTX), an opiate antagonist, can block excitatory opioid receptors without affecting inhibitory opioid receptors, resulting in analgesic potency without side effects. The present study assessed the efficacy and safety of PTI-901 (low-dose NTX) treatment in Irritable bowel syndrome (IBS) patients. Forty-two IBS patients participated in an open-label study. Participants received 0.5 mg PTI-901/day for 4 weeks and were evaluated during baseline, during treatment, and at 4-week follow-up. Patients recorded degree of abdominal pain, stool urgency, consistency, and frequency. Primary outcomes were number of pain-free days and overall symptom relief, evaluated by a global assessment score. Data were analyzed per protocol. Global assessment improved in 76% of 42 patients. During treatment, the mean weekly number of pain-free days increased from 0.5+/-1 to 1.25+/-2.14 (P=0.011). There were no significant adverse reactions. PTI-901 improves pain and overall feeling, and is well tolerated by IBS patients. A large, randomized, double-blind, placebo-controlled study is justified.

The burden of gastrointestinal and liver diseases, 2006

BACKGROUND

Digestive and liver diseases are a source of significant morbidity, mortality, and health-care costs for the U.S. population. An annual report of the toll of these diseases could be helpful to clinicians, policymakers, and researchers.

AIM

To describe the epidemiology of gastrointestinal and liver diseases in the United States using data from privately and publicly held databases.

METHODS

We collected data from the National Center for Health Statistics, the National Ambulatory Medical Care Survey, the National Inpatient Sample, the Centers for Disease Control and Prevention, and the National Cancer Institute, as well as proprietary pharmaceutical databases to construct a report on the impact of gastrointestinal and liver diseases on the U.S. population. We compiled information on causes of death, hospitalization, clinic visits, cancer incidence, and mortality and infectious disease incidence from these databases, and extracted data specific to gastrointestinal diseases. Because of the high costs associated with medications used to treat gastrointestinal diseases, we also include in this year's report a special section on pharmacoepidemiology and pharmacoeconomics.

RESULTS

Colorectal cancer continues to be the leading cause of GI-related death, although the data indicate a downward trend in deaths. Abdominal pain, diarrhea, vomiting, and nausea are the most common GI symptoms precipitating a visit to the physician, and GERD is the most common GI-related diagnosis given in office visits. Chest pain not specified to be cardiac in origin is the most common cause of inpatient admission possibly related to GI disease, with cholelithiasis and pancreatitis following. Americans spend in excess of US dollars 10 billion/yr on proton pump inhibitors (PPIs), and two of the top five selling drugs in the United States are PPIs. Trends in PPI use demonstrate turbulent changes, likely reflecting both new drug entries into the field, as well as drug marketing. The number of PPI prescriptions/yr in the United States has doubled since 1999. Twenty-three drugs used for gastrointestinal diseases are among the top 200 generic drugs used in the United States.

CONCLUSIONS

Gastrointestinal and liver diseases are significant contributors to the morbidity, mortality, and health-care expenditures of the U.S. population.

New directions in brain imaging research in functional gastrointestinal disorders

Functional brain imaging has greatly enhanced the ability to investigate brain-gut interactions and to assess the central nervous system role on visceral pain perception. The results of studies using brain imaging in irritable bowel syndrome (IBS) have demonstrated differences in brain activation between patients with IBS and healthy controls. In addition, the more recent studies are starting to shed light on pathophysiological mechanisms that underlie the generation of functional gastrointestinal (GI) symptoms as well as the response to treatment. These studies highlight the potential of functional brain imaging to become an important and exciting investigative tool in research of functional GI disorders. However, the multifactorial, multideterminant nature of these disorders, the current limitations in the understanding of the pathophysiology of the disorders, and the heterogeneous patient population make brain imaging research in this field difficult and require caution in the interpretation of the data. The continued development of brain imaging techniques provides not only exciting opportunities but also significant challenges to the field. This article focuses on brain imaging research in functional GI disorders. It describes some of the recent developments in the use of brain imaging in research of the brain-gut axis and provides an overview of the current data.

Selected topics in probiotics and prebiotics: meeting report for the 2004 international scientific association for probiotics and prebiotics

On August 29-31, 2004, 84 academic and industry scientists from 16 countries gathered in Copper Mountain, Colorado USA to discuss certain issues at the forefront of the science of probiotics and prebiotics. The format for this invitation only meeting included six featured lectures: engineering human vaginal lactobacilli to express HIV-inhibitory molecules (Peter Lee, Stanford University), programming the gut for health (Thaddeus Stappenbeck, Washington University School of Medicine), immune modulation by intestinal helminthes (Joel Weinstock, University of Iowa Hospitals and Clinics), hygiene as a cause of autoimmune disorders (G. A. Rook, University College London), prebiotics and bone health (Connie Weaver, Purdue University) and prebiotics and colorectal cancer risk (Ian Rowland, Northern Ireland Centre for Food and Health). In addition, all participants were included in one of eight discussion groups on the topics of engineered probiotics, host-commensal bacteria communication, 'omics' technologies, hygiene and immune regulation, biomarkers for healthy people, prebiotic and probiotic applications to companion animals, development of a probiotic dossier, and physiological relevance of prebiotic activity. Brief conclusions from these discussion groups are summarized in this paper.