Past and current theories of etiology of IBD: toothpaste, worms, and refrigerators

Colitis-associated intestinal microbiota regulates brain glycine and host behavior in mice

Inflammatory bowel diseases (IBD) are chronic and relapsing inflammatory disorders of the gastrointestinal tract with complex etiology and no strategies for complete cure. IBD are often complicated by mental disorders like anxiety and depression, indicating substantial shifts in the microbiota gut-brain axis. However, the mechanisms connecting IBD to mental diseases are still under debate. Here we use Muc2 knockout mouse model of chronic colitis to uncouple the effects of the intestinal microbiota on host behavior from chronic inflammation in the gut. Muc2 knockout male mice exhibit high exploratory activity, reduced anxiety-related behaviors, impaired sensorimotor gating, and altered social preference towards males and females. Microbial transfer to wild-type mice via littermate co-housing shows that colitis-associated microbiota rather than inflammation per se defines behavioral features in Muc2 colitis model. Metagenomic profiling and combination of antibiotic treatments revealed that bacterial species Akkermansia muciniphila is associated with the behavioral phenotype in mutants, and that its intestinal abundance correlates with social preference towards males. Metabolomic analysis together with pharmacological inhibition of Gly and NMDA receptors helped us to determine that brain glycine is responsible for the behavioral phenotype in Muc2 mice. Blood and brain metabolic profiles suggest that microbiota-dependent changes in choline metabolism might be involved in regulation of central glycine neurotransmission. Taken together, our data demonstrates that colitis-associated microbiota controls anxiety, sensorimotor gating and social behavior via metabolic regulation of the brain glycinergic system, providing new venues to combat neurological complications of IBD.

Environmental factors associated with biological use and surgery in inflammatory bowel disease

BACKGROUND AND AIM

While major efforts were made studying the complex etiology of inflammatory bowel disease (IBD) including environmental factors, less is known about underlying causes leading to the heterogeneous and highly variable course of disease. As cigarette smoking cessation is the best-known environmental factor with beneficial effect in Crohn's disease (CD), more exposome factors are likely involved. Further insights into the role of the exposome in heterogeneity of disease might not only further knowledge of underlying pathways, but also allow for better risk stratification.

METHODS

Seven hundred twenty-eight IBD patients completed the validated Groningen IBD Environmental Questionnaire, collecting exposome data for 93 exposome factors. Associations with disease course, that is, for need for surgery or biological therapy, were evaluated using univariate and multivariate-adjusted logistic regression modeling.

RESULTS

No significant associations were seen after Bonferroni correction. However, 11 novel exposome factors were identified with P < 0.05. Two factors were associated with course of CD and ulcerative colitis (UC): beer (CD OR0.3/UC OR0.3) and cannabis (0.5/2.2). While in CD, carpet flooring (0.5) was associated with biological use, and four factors were associated with surgery: working shifts (1.8), appendectomy (2.4), frequent tooth brushing (2.8), and large household size (0.1). For UC, migrants more often required biologicals (10.2). Childhood underweight (3.4), amphetamine use (6.2), and cocaine use (4.8) were associated with surgery. Five factors were replicated.

CONCLUSIONS

We identified 16 environmental factors nominally associated with biological use and surgery in established IBD. These new insights form an important stepping stone to guide research on biological pathways involved, risk stratification, tailor-made interventions, and preventive strategies in IBD.

The Influence of Breastfeeding, Cesarean Section, Pet Animals, and Urbanization on the Development of Inflammatory Bowel Disease: Data from the Swiss IBD Cohort Study

Introduction

The pathophysiology of inflammatory bowel disease (IBD) is incompletely understood. Current concepts imply that environmental factors (EFs) trigger disease onset as well as flares in genetically susceptible individuals.

Objective

The objective of this study is to analyze the association between IBD and various EFs, which may influence the pathogenesis of the disease.

Methods

2,294 patients from the Swiss IBD Cohort Study (SIBDCS) received a questionnaire regarding EF including mode of delivery, breastfeeding, animals in household, and place of residence. The control group comprised patients' childhood friends, who grew up in a similar environment ("friends cohort").

Results

A total of 1,111 questionnaires were returned from SIBDCS patients (response rate: 48.4%). Breastfeeding for <6 months was associated with a decreased risk for ulcerative colitis/indeterminate colitis (UC/IC) (OR: 0.473, p = 0.006). IBD patients reported less pet animals in the household than the control group (p = 0.004). The presence of cats or dogs (OR: 0.688, p = 0.015) and pet rodents (OR: 0.598, p = 0.001) in the household before the age of 20 was inversely associated with the risk for UC/IC.

Conclusion

The present study underlines the importance of EFs in the pathogenesis of IBD. Overall, the development of UC/IC seems to be more affected from environmental influences than from Crohn's disease. Our results imply a protective effect of possessing pet animals in household and short breastfeeding regarding the onset of UC/IC.

Examination of food consumption in United States adults and the prevalence of inflammatory bowel disease using National Health Interview Survey 2015

Various diets and food components have been implicated as one of the environmental factors associated with inflammatory bowel disease (IBD). Patients are often recommended nutritional guidelines to manage disease symptoms. However, the current food consumption pattern of US adults with IBD that are nationally representative is unclear. A secondary analysis of National Health Interview Survey 2015 was performed to characterize the estimated US adults with IBD and their food intake and consumption frequency using bivariate and multivariate logistic regression. Fries were consumed by a greater number of people with IBD. IBD population drank less 100% fruit juice and ate more cheese and cookies than non-IBD population. Intake of fries (OR 1.60, 95% CI 1.14-2.25) and sports and energy drinks (OR 1.46, 95% CI 1.07-1.97) and more frequent drinking of regular soda were significantly associated with the likelihood of having been told one have IBD, while popcorn (OR 0.73, 95% CI 0.548-0.971) and milk (OR 0.70, 95% CI 0.497-0.998) were associated with smaller odds, adjusting for covariates. Foods typically labeled as junk food were positively associated with IBD. Nonetheless, of the assessed 26 foods, we found eating patterns between IBD and non-IBD population to be mostly analogous. It is unclear whether the results reflect potential change in food intake in IBD population long before the survey interview. Understanding the role of food intake in IBD risk/prevalence would benefit from identifying other environmental factors (i.e. food desert), food processing (i.e. frying), and potential bioactive food components that can induce intestinal inflammation that can increase the individual's susceptibility to IBD.

Risks of developing ulcerative colitis and Crohn's disease in relation to silica dust exposure in Sweden: a case-control study

OBJECTIVE

To determine whether occupational exposure to silica dust causes an increased risk of developing Crohn's disease (CD) and ulcerative colitis (UC).

DESIGN

Case-control study of CD (K50) and UC (K51) from 2007 through 2016. Controls were matched to cases (2:1) based on age, sex and county at the time of diagnosis. A job exposure matrix was used to estimate the occupational silica exposure of all cases and controls.

SETTING

Medical and occupational data from the National Outpatient Register were used to implement a case-control analysis, while the two controls used for each case were selected from the National Register of the Total Population.

PARTICIPANTS

All men and women aged 20-65 years old who were diagnosed with CD (K50) and UC (K51) during the years of study were included and assigned two controls, resulting in 58 136 cases and 116 272 controls.

MAIN OUTCOMES

Silica dust exposure correlates with an increased risk of developing UC in men and CD in women.

RESULTS

The prevalence of UC was significantly higher in the group exposed to silica dust (OR 1.13, 95% CI 1.06 to 1.21) than in controls, particularly in individuals with over 5 years exposure. When stratified by sex, a significantly increased OR was detected for men (OR 1.33, 95% CI 1.05 to 1.22). This trend was also consistent with longer exposure times. The prevalence of UC was not increased in exposed women. The prevalence of CD was significantly increased among exposed women (OR 1.29, 95% CI 1.01 to 1.65), but not for exposed men.

CONCLUSIONS

Silica dust exposure correlates with an increased risk of developing UC, especially in men, and the risk seems to increase with the duration and degree of exposure. Conversely, silica dust exposure correlates positively with the risk of developing CD in women.

History of Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the intestinal mucosa and unknown etiology. In this review, we identified three main eras in the IBD history. Between the 19th and the 20th century, the primary task had been the definition of the diagnostic criteria in order to differentiate the new entity from intestinal tuberculosis. In the 20th century, an intense and prolific therapeutic research prevailed, culminating in the introduction of biological drugs in the clinical setting. Since the beginning of the 21st century, traditional definition criteria have been challenged by holistic criteria in an effort to seek a still unattained cure. Centuries of worldwide efforts on IBD etiology and therapy search have culminated in this novel strategy.

Urbanization and the gut microbiota in health and inflammatory bowel disease

In the 21st century, urbanization represents a major demographic shift in developed and developing countries. Rapid urbanization in the developing world has been associated with an increasing incidence of several autoimmune diseases, including IBD. Patients with IBD exhibit a decrease in the diversity and richness of the gut microbiota, while urbanization attenuates the gut microbial diversity and might have a role in the pathogenesis of IBD. Environmental exposures during urbanization, including Westernization of diet, increased antibiotic use, pollution, improved hygiene status and early-life microbial exposure, have been shown to affect the gut microbiota. The disparate patterns of the gut microbiota composition in rural and urban areas offer an opportunity to understand the contribution of a 'rural microbiome' in potentially protecting against the development of IBD. This Perspective discusses the effect of urbanization and its surrogates on the gut microbiome (bacteriome, virome, mycobiome and helminths) in both human health and IBD and how such changes might be associated with the development of IBD.

Forgotten fungi-the gut mycobiome in human health and disease

The human body is home to a complex and diverse microbial ecosystem that plays a central role in host health. This includes a diversity of fungal species that is collectively referred to as our 'mycobiome'. Although research into the mycobiome is still in its infancy, its potential role in human disease is increasingly recognised. Here we review the existing literature available on the human mycobiota with an emphasis on the gut mycobiome, including how fungi interact with the human host and other microbes. In doing so, we provide a comprehensive critique of the methodologies available to research the human mycobiota as well as highlighting the latest research findings from mycological surveys of different groups of interest including infants, obese and inflammatory bowel disease cohorts. This in turn provides new insights and directions for future studies in this burgeoning research area.

Is There a Link Between H. Pylori and the Epidemiology of Crohn's Disease?

INTRODUCTION

Case control studies suggest an inverse association between Helicobacter pylori (H. pylori) and Crohn's disease (CD). It is possible this could be accounted for by confounders such as antibiotic therapy. Analyzing the geographic distribution of H. pylori and the links with the incidence and prevalence of CD would be an alternative approach to circumvent these confounders.

METHODS

The literature was searched for studies published between 1990 and 2016 that reported incidence or prevalence data for CD in random population samples in developed countries (GDP per capita >20,000 USD/year). Corresponding prevalence studies for H. pylori in these same regions were then sought matched to the same time period (±6 years). The association between the incidence and prevalence of CD and H. pylori prevalence rates were assessed before and after adjusting for GDP and life expectancy.

RESULTS

A total of 19 CD prevalence and 22 CD incidence studies from 10 European countries, Japan, USA, and Australia with date-matched H. pylori prevalence data were identified. The mean H. pylori prevalence rate was 43.4% (range 15.5-85%), and the mean rates for incidence and prevalence for CD were 6.9 and 91.0/100,000 respectively. The incidence (r = -0.469, p < 0.03) and prevalence (r = -0.527, p = 0.02) of CD was inversely and significantly associated with prevalence of H. pylori infection.

CONCLUSIONS

Our data demonstrate a significant inverse association between geographic distribution of H. pylori and CD. Thus, it is highly unlikely that the findings of previous case control studies were simply due to confounding factors such as concomitant antibiotic use in CD patients.

The association between environmental exposures during childhood and the subsequent development of Crohn's disease: A score analysis approach

BACKGROUND

Environmental factors during childhood are thought to play a role in the aetiology of Crohn's Disease (CD). In South Africa, recently published work based on an investigation of 14 childhood environmental exposures during 3 age intervals (0-5, 6-10 and 11-18 years) has provided insight into the role of timing of exposure in the future development of CD. The 'overlapping' contribution of the investigated variables however, remains unclear. The aim of this study was to perform a post hoc analysis using this data and investigate the extent to which each variable contributes to the subsequent development of CD relative to each aforementioned age interval, based on a score analysis approach.

METHODS

Three methods were used for the score analysis. Two methods employed the subgrouping of one or more (similar) variables (methods A and B), with each subgroup assigned a score value weighting equal to one. For comparison, the third approach (method 0) involved no grouping of the 14 variables. Thus, each variable held a score value of one.

RESULTS

Results of the score analysis (Method 0) for the environmental exposures during 3 age intervals (0-5, 6-10 and 11-18 years) revealed no significant difference between the case and control groups. By contrast, results from Method A and Method B revealed a significant difference during all 3 age intervals between the case and control groups, with cases having significantly lower exposure scores (approximately 30% and 40% lower, respectively).

CONCLUSION

Results from the score analysis provide insight into the 'compound' effects from multiple environmental exposures in the aetiology of CD.

Inflammatory bowel disease: exploring gut pathophysiology for novel therapeutic targets

Ulcerative colitis and Crohn's disease are the 2 major phenotypes of inflammatory bowel disease (IBD), which are influenced by a complex interplay of immunological and genetic elements, though the precise etiology still remains unknown. With IBD developing into a globally prevailing disease, there is a need to explore new targets and a thorough understanding of the pathophysiological differences between the healthy and diseased gut could unearth new therapeutic opportunities. In this review, we provide an overview of the major aspects of IBD pathogenesis and thereafter present a comprehensive analysis of the gut pathophysiology leading to a discussion on some of the most promising targets and biologic therapies currently being explored. These include various gut proteins (CXCL-10, GATA-3, NKG2D, CD98, microRNAs), immune cells recruited to the gut (mast cells, eosinophils, toll-like receptors 2, 4), dysregulated proinflammatory cytokines (interleukin-6, -13, -18, -21), and commensal microbiota (probiotics and fecal microbiota transplantation). We also evaluate some of the emerging nonconventional therapies being explored in IBD treatment focusing on the latest developments in stem cell research, oral targeting of the gut-associated lymphoid tissue, novel anti-inflammatory signaling pathway targeting, adenosine deaminase inhibition, and the beneficial effects of antioxidant and nutraceutical therapies. In addition, we highlight the growth of biologics and their targets in IBD by providing information on the preclinical and clinical development of over 60 biopharmaceuticals representing the state of the art in ulcerative colitis and Crohn's disease drug development.

Lycopene, Lutein and Zeaxanthin May Reduce Faecal Blood, Mucus and Pus but not Abdominal Pain in Individuals with Ulcerative Colitis

BACKGROUND

The main symptom of ulcerative colitis is diarrhoea, which is often accompanied by painful tenesmus and faecal blood and mucus. It sometimes co-occurs with abdominal pain, fever, feeling of fatigue, loss of appetite and weight loss. Some dietary factors have been indicated as important in the treatment of ulcerative colitis. The aim of the study was to analyse the association between retinoid intake (total vitamin A, retinol, β-carotene, α-carotene, β-cryptoxanthin, lycopene, lutein and zeaxanthin) and ulcerative colitis symptoms (abdominal pain, faecal blood, faecal mucus, faecal pus) in individuals with ulcerative colitis in remission.

METHODS

Assessment of diet was based on self-reported data from each patient's dietary records taken over a period of three typical, random days (2 weekdays and 1 day of the weekend).

RESULTS

A total of 56 individuals with ulcerative colitis in remission (19 males and 37 females) were recruited for the study. One in every four individuals with ulcerative colitis in remission was characterised as having inadequate vitamin A intake. Higher lycopene, lutein and zeaxanthin intakes in individuals with ulcerative colitis in remission were associated with lower faecal blood, mucus and pus but not with lower incidence of abdominal pain. Higher carotene intake in individuals with ulcerative colitis in remission may contribute to higher incidence of faecal mucus.

CONCLUSIONS

Optimising intake of specific retinoids may enhance disease control in individuals with ulcerative colitis. Prospective studies, including patient reported and objective outcomes, are required to confirm this.

Influence of environmental factors in the development of inflammatory bowel diseases

Idiopathic inflammatory bowel diseases (IBD), Crohn’s disease (CD) and ulcerative colitis (UC), are multifactorial diseases that are manifested after disruption of a genetic predisposed individual and its intestinal microflora through an environmental stimulus. Urbanization and industrialization are associated with IBD. Epidemiological data, clinical observations and family/immigrants studies indicate the significance of environmental influence in the development of IBD. Some environmental factors have a different effect on the subtypes of IBD. Smoking and appendectomy is negatively associated with UC, but they are aggravating factors for CD. A westernized high fat diet, full of refined carbohydrates is strongly associated with the development of IBD, contrary to a high in fruit, vegetables and polyunsaturated fatty acid-3 diet that is protective against these diseases. High intake of nonsteroidal antiinflammatory drug and oral contraceptive pills as well as the inadequacy of vitamin D leads to an increased risk for IBD and a more malignant course of disease. Moreover, other factors such as air pollution, psychological factors, sleep disturbances and exercise influence the development and the course of IBD. Epigenetic mechanism like DNA methylation, histone modification and altered expression of miRNAS could explain the connection between genes and environmental factors in triggering the development of IBD.

Inflammatory Bowel Disease Environmental Risk Factors: A Population-Based Case-Control Study of Middle Eastern Migration to Australia

BACKGROUND & AIMS

The incidences of the inflammatory bowel diseases (IBDs) Crohn's disease (CD) and ulcerative colitis (UC) are increasing, indicating gene-environment interactions. Migrants from low-IBD-prevalence countries to a high-prevalence country may help identify the relative contribution of environmental risk factors compared with native Caucasians.

METHODS

This prospective case-control study evaluated IBD environmental risk factors of Middle Eastern migrants (MEM) in Australia compared with matched Caucasian IBD subjects, MEM controls, Caucasian controls, and controls in the Middle East using adjusted odds ratios (aOR).

RESULTS

A total of 795 subjects were recruited: 154 MEM cases (75 CD; 79 UC), 153 MEM controls, 162 Caucasian cases (85 CD; 77 UC), 173 Caucasian controls, and 153 controls in Lebanon. Smoking increased CD risk in MEM and Caucasians and reduced UC risk in Caucasians (aOR, 0.77; 95% CI, 0.41-0.98) but not MEM (aOR, 1.45; 95% CI, 0.80-2.62). Antibiotic use reduced the risk of MEM CD (aOR, 0.27; 95% CI, 0.11-0.67) and UC (aOR, 0.38; 95% CI, 0.18-0.80), but increased the risk in Caucasians (CD: aOR, 5.24; 95% CI, 2.13-12.90; and UC: aOR, 6.82; 95% CI, 2.67-17.38). Most hygiene markers (rural dwelling, pet ownership, pet feeding, and farm animal contact) reduced CD and UC risk in MEM (P < .05). In contrast, in Caucasians these hygiene markers lacked significance. Other significant risk factors include IBD family history, appendectomy, tonsillectomy, and breastfeeding.

CONCLUSIONS

Differential IBD environmental risk factors exist between migrants and native Caucasians, indicating a dynamic interplay between environmental factors and IBD risk for immigrants that is distinct to those factors most relevant in native Caucasians.

Inflammatory bowel disease

Scandinavian researchers have contributed to the present understanding of inflammatory bowel disease (IBD). Important epidemiological data and family risk factors have been reported from all the Nordic countries, original twin studies mainly from Denmark and Sweden, and relationships to cancer and surgery mostly from Sweden. In collaboration with the industry, development of medical compounds was for a long time in the front line of international research, and the Scandinavian countries participated in the clinical breakthrough of biologic treatment. At present, many Nordic centers are working in the forefront of IBD research. An increasing number of young investigators have entered the scene along with the extended distribution of University clinics and research laboratories in these countries. This presentation of IBD gives a brief overview in the fields of clinical epidemiology and molecular biology. Many areas are covered by International collaborations with partners from Nordic centers. IBD was a topic focused by the founders of Scandinavian Journal of Gastroenterology. After 50 years one may state that the journal's history reflects important pieces of scientific knowledge within these diseases. The early scope of Johannes Myren for IBD was shown through his work in the original World Association of Gastroenterology (OMG), and after 50 years we can clearly support the view that global perspectives in IBD are increasingly important.

Environment and the inflammatory bowel diseases

Inflammatory bowel diseases (IBD), which consists of Crohn disease and ulcerative colitis, are chronic inflammatory conditions of the gastrointestinal tract. In genetically susceptible individuals, the interaction between environmental factors and normal intestinal commensal flora is believed to lead to an inappropriate immune response that results in chronic inflammation. The incidence of IBD have increased in the past century in developed and developing countries. The purpose of the present review is to summarize the current knowledge of the association between environmental risk factors and IBD. A number of environmental risk factors were investigated including smoking, hygiene, microorganisms, oral contraceptives, antibiotics, diet, breastfeeding, geographical factors, pollution and stress. Inconsistent findings among the studies highlight the complex pathogenesis of IBD. Additional studies are necessary to identify and elucidate the role of environmental factors in IBD etiology.

Smoking, breastfeeding, physical inactivity, contact with animals, and size of the family influence the risk of inflammatory bowel disease: A Slovak case-control study

BACKGROUND

The aetiology of inflammatory bowel disease (IBD) is not known but is likely to involve a combination of genetic predisposition and environmental risk factors. Smoking has been associated consistently with a higher risk of Crohn's disease (CD), while appendectomy and smoking appear to diminish the risk of ulcerative colitis (UC). The roles of other environmental factors are unclear. The aim of the present study was to evaluate the association of CD and UC with several environmental risk factors.

METHODS

This case-control study included 338 patients (190 CD, 148 UC) and 355 controls. All subjects completed a detailed questionnaire regarding breastfeeding duration, history of helminthic infections, allergic diseases, appendectomy, household size, housing type, contact with specific domestic animals, physical activity, and smoking. Associations between risk factors and CD and UC were investigated by univariate and multivariate analysis.

RESULTS

On multivariate analysis, CD associated with smoking at diagnosis (odds ratio, OR, 3.7, 95% CI 2.2-6.2; p < 0.001), being breastfed for <6 months (OR 2.7, 95% CI 1.7-4.4; p < 0.001), and less than two childhood sporting activities weekly (OR 2.7, 95% CI 1.5-5.0; p < 0.001) and inversely associated with frequent contact with cats in childhood (OR 0.6, 95% CI 0.4-0.9; p < 0.03). UC associated with less than two sporting weekly activities in childhood (OR 2.0, 95% CI 1.1-3.5, p = 0.02), fewer household members in childhood (OR 0.8, 95% CI 0.7-0.98, p = 0.03), and being breastfed for <6 months (OR 1.7, 95% CI 1.02-2.8, p = 0.04). A composite environmental risk index for CD revealed that 47 and 14% of the controls and patients with CD had no risk factors, respectively, and that 14 and 38% of the controls and patients with CD had at least two risk factors, respectively.

CONCLUSION

CD and UC associated with infrequent childhood sports activities and short breastfeeding. Furthermore, CD associated with smoking and infrequent contact with animals in childhood. UC associated with a smaller family size in childhood.

Modulatory effects of sesamol in dinitrochlorobenzene-induced inflammatory bowel disorder in albino rats

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of gastrointestinal tract of immune, genetic and environmental origin. In the present study, we examined the effect of sesamol (SES), the main anti-oxidative constituent of Sesamum indicum (sesame seed) Linn. in the dinitrochlorobenzene (DNCB)-induced model for IBD in rats.

METHODS

The groups were divided into normal control, DNCB control, SES and sulfasalazine (SS). On day 24, the rats were killed, colon removed and the macroscopic, biochemical and histopathological evaluations were performed.

RESULTS

The levels of MPO, TBARS and nitrite increased significantly (p < 0.05) in the DNCB group, whereas reduced significantly in the SES, SS treated groups. Serum nitrite levels were found to be insignificant between the different groups. IL-6 and TNF-α levels were significantly high in the DNCB group.

CONCLUSIONS

We conclude the mucosal protective effect of SES on colon due to its potent antioxidant actions. Further investigation is required in a chronic model of different rodent strain for its role involved in the cytokine pathway.

Pathogenic Yersinia DNA in intestinal specimens of pediatric patients with Crohn's disease

Studies indicate a close relationship between Yersinia and Crohn's disease in adults. Our study tested 77 colonic specimens from children with Crohn's disease for the presence of Yersinia DNA using a validated polymerase chain reaction (PCR) assay. Control cases included specimens from 45 ulcerative colitis patients and 10 appendicitis patients. The presence of Yersinia in Crohn's specimens was significant compared to the control specimens (9% vs. 0%; p = 0.0055). While our study supports the medical literature, future studies are needed to determine if the relationship between Crohn's disease and Yersinia is an initiating or mediating factor in the pathogenesis of pediatric Crohn's disease.

The role of the microbiome in rheumatic diseases

There is a growing understanding of the mechanisms by which the influence of the microbiota projects beyond sites of primary mucosal occupation to other human body systems. Bacteria present in the intestinal tract exert a profound effect on the host immune system, both locally and at distant sites. The oral cavity has its own characteristic microbiota, which concentrates in periodontal tissues and is in close association with a permeable epithelium. In this review we examine evidence which supports a role for the microbiome in the aetiology of rheumatic disease. We also discuss how changes in the composition of the microbiota, particularly within the gastrointestinal tract, may be affected by genetics, diet, and use of antimicrobial agents. Evidence is presented to support the theory that an altered microbiota is a factor in the initiation and perpetuation of inflammatory diseases, including rheumatoid arthritis (RA), spondyloarthritis (SpA), and inflammatory bowel disease (IBD). Mechanisms through which the microbiota may be involved in the pathogenesis of these diseases include altered epithelial and mucosal permeability, loss of immune tolerance to components of the indigenous microbiota, and trafficking of both activated immune cells and antigenic material to the joints. The potential to manipulate the microbiome, by application of probiotics and faecal microbial transplant (FMT), is now being investigated. Both approaches are in their infancy with regard to management of rheumatic disease but their potential is worthy of consideration, given the need for novel therapeutic approaches, and the emerging recognition of the importance of microbial interactions with human hosts.

Comparative protective effect of hawthorn berry hydroalcoholic extract, atorvastatin, and mesalamine on experimentally induced colitis in rats

The protective effect of hydroalcoholic extract of hawthorn berries (HBE) on acetic acid (AA)-induced colitis in rats was investigated. Forty-two Wistar rats were divided into seven groups, including control and test groups (n=6). The control animals received saline, and the test animals were treated with saline (sham group), mesalamine (50 mg/kg; M group), atorvastatin (20 mg/kg; A group), HBE (100 mg/kg; H group), mesalamine and HBE (HM group), or atorvastatin plus HBE (HA group), 3 days before and a week after colitis induction. Colitis was induced by administration of 1 mL AA (4%) via a polyethylene catheter intrarectally. High-performance liquid chromatography analyses showed that HBE contained 0.13% and 0.5% oleanolic acid and ursolic acid, respectively. Elevated myeloperoxidase activity and lipid peroxidation were attenuated in the HA group. The H and HM groups showed marked reductions in colitis-induced decreases in total thiol molecules and body weight. The histopathological studies revealed that HBE decreased colitis-induced edema and infiltration of neutrophils. Our data suggest the anti-inflammatory and antioxidant effects of HBE and atorvastatin protect against AA-induced colitis. The anti-inflammatory effect of HBE may be attributable to its ability to decrease myeloperoxidase activity as a biomarker of neutrophil infiltration.

The organisation and structure of inflammatory bowel disease services for children and young people in the UK in 2010: significant progress but still room for improvement

BACKGROUND

Inflammatory bowel disease (IBD) is becoming more common in children. While treatment options remain limited the appropriate organisation and delivery of services are an integral part of good care.

METHODS

All eligible UK paediatric sites were invited to submit data for organisation of paediatric IBD services as of 1 September 2010. Comparison, when relevant, was made with the previous paediatric audit (2008) and the concurrently running adult audit.

RESULTS

24/25 (96%) of sites submitted data. The median number of patients managed and the median number of new IBD (ulcerative colitis and Crohn's disease only) cases per annum was 178 (IQR 136-281) and 32 (IQR 23-50), respectively. There was an increase in the IBD workforce including whole-time equivalent (WTE) IBD nurses (1.0 vs 1.5 WTE nurses, p=0.02). 1023 patients 16 years and younger were looked after in the 202 adult sites who submitted data; only 78/202 sites indicated they cared for 16-year-old and younger children; approximately half of these 78 sites had age-appropriate support facilities. Most paediatric sites have access to urgent endoscopy (83%), telephone advice (100%) and urgent clinic appointments (91%). Most sites did not have: shared care pathways with primary care (74%), annual reviews (71%), real time patient management systems (83%) and research network trial participation (78%).

CONCLUSIONS

Many aspects of paediatric IBD care in the UK are good and have shown significant improvement over recent years. There are areas in need of further change and specific regional and national action plans should address identified deficiencies before any future audit of paediatric and adult IBD services.

Nutrigenomics and nutrigenetics in inflammatory bowel diseases

Inflammatory bowel diseases (IBD) including ulcerative colitis and Crohn's disease are chronically relapsing, immune-mediated disorders of the gastrointestinal tract. A major challenge in the treatment of IBD is the heterogenous nature of these pathologies. Both, ulcerative colitis and Crohn's disease are of multifactorial etiology and feature a complex interaction of host genetic susceptibility and environmental factors such as diet and gut microbiota. Genome-wide association studies identified disease-relevant single-nucleotide polymorphisms in approximately 100 genes, but at the same time twin studies also clearly indicated a strong environmental impact in disease development. However, attempts to link dietary factors to the risk of developing IBD, based on epidemiological observations showed controversial outcomes. Yet, emerging high-throughput technologies implying complete biological systems might allow taking nutrient-gene interactions into account for a better classification of patient subsets in the future. In this context, 2 new scientific fields, "nutrigenetics" and "nutrigenomics" have been established. "Nutrigenetics," studying the effect of genetic variations on nutrient-gene interactions and "Nutrigenomics," describing the impact of nutrition on physiology and health status on the level of gene transcription, protein expression, and metabolism. It is hoped that the integration of both research areas will promote the understanding of the complex gene-environment interaction in IBD etiology and in the long-term will lead to personalized nutrition for disease prevention and treatment. This review briefly summarizes data on the impact of nutrients on intestinal inflammation, highlights nutrient-gene interactions, and addresses the potential of applying "omic" technologies in the context of IBD.

The relationship between urban environment and the inflammatory bowel diseases: a systematic review and meta-analysis

BACKGROUND

The objective of this study was to conduct a systematic review with meta-analysis of studies assessing the association between living in an urban environment and the development of the Crohn's disease (CD) or ulcerative colitis (UC).

METHODS

A systematic literature search of MEDLINE (1950-Oct. 2009) and EMBASE (1980-Oct. 2009) was conducted to identify studies investigating the relationship between urban environment and IBD. Cohort and case-control studies were analyzed using incidence rate ratio (IRR) or odds ratio (OR) with 95 % confidence intervals (CIs), respectively. Stratified and sensitivity analyses were performed to explore heterogeneity between studies and assess effects of study quality.

RESULTS

The search strategy retrieved 6940 unique citations and 40 studies were selected for inclusion. Of these, 25 investigated the relationship between urban environment and UC and 30 investigated this relationship with CD. Included in our analysis were 7 case-control UC studies, 9 case-control CD studies, 18 cohort UC studies and 21 cohort CD studies. Based on a random effects model, the pooled IRRs for urban compared to rural environment for UC and CD studies were 1.17 (1.03, 1.32) and 1.42 (1.26, 1.60), respectively. These associations persisted across multiple stratified and sensitivity analyses exploring clinical and study quality factors. Heterogeneity was observed in the cohort studies for both UC and CD, whereas statistically significant heterogeneity was not observed for the case-control studies.

CONCLUSIONS

A positive association between urban environment and both CD and UC was found. Heterogeneity may be explained by differences in study design and quality factors.

The relationship between urban environment and the inflammatory bowel diseases: a systematic review and meta-analysis

Background

The objective of this study was to conduct a systematic review with meta-analysis of studies assessing the association between living in an urban environment and the development of the Crohn’s disease (CD) or ulcerative colitis (UC).

Methods

A systematic literature search of MEDLINE (1950-Oct. 2009) and EMBASE (1980-Oct. 2009) was conducted to identify studies investigating the relationship between urban environment and IBD. Cohort and case–control studies were analyzed using incidence rate ratio (IRR) or odds ratio (OR) with 95 % confidence intervals (CIs), respectively. Stratified and sensitivity analyses were performed to explore heterogeneity between studies and assess effects of study quality.

Results

The search strategy retrieved 6940 unique citations and 40 studies were selected for inclusion. Of these, 25 investigated the relationship between urban environment and UC and 30 investigated this relationship with CD. Included in our analysis were 7 case–control UC studies, 9 case–control CD studies, 18 cohort UC studies and 21 cohort CD studies. Based on a random effects model, the pooled IRRs for urban compared to rural environment for UC and CD studies were 1.17 (1.03, 1.32) and 1.42 (1.26, 1.60), respectively. These associations persisted across multiple stratified and sensitivity analyses exploring clinical and study quality factors. Heterogeneity was observed in the cohort studies for both UC and CD, whereas statistically significant heterogeneity was not observed for the case–control studies.

Conclusions

A positive association between urban environment and both CD and UC was found. Heterogeneity may be explained by differences in study design and quality factors.

Etiology of inflammatory bowel disease: a unified hypothesis

Inflammatory bowel disease (IBD), including both ulcerative colitis (UC) and Crohn's disease (CD), emerged and dramatically increased for about a century. Despite extensive research, its cause remains regarded as unknown. About a decade ago, a series of findings made me suspect that saccharin may be a key causative factor for IBD, through its inhibition on gut bacteria and the resultant impaired inactivation of digestive proteases and over digestion of the mucus layer and gut barrier (the Bacteria-Protease-Mucus-Barrier hypothesis). It explained many puzzles in IBD such as its emergence and temporal changes in last century. Recently I further found evidence suggesting sucralose may be also linked to IBD through a similar mechanism as saccharin and have contributed to the recent worldwide increase of IBD. This new hypothesis suggests that UC and CD are just two symptoms of the same morbidity, rather than two different diseases. They are both caused by a weakening in gut barrier and only differ in that UC is mainly due to increased infiltration of gut bacteria and the resultant recruitment of neutrophils and formation of crypt abscess, while CD is mainly due to increased infiltration of antigens and particles from gut lumen and the resultant recruitment of macrophages and formation of granulomas. It explained the delayed appearance but accelerated increase of CD over UC and many other phenomena. This paper aims to provide a detailed description of a unified hypothesis regarding the etiology of IBD, including the cause and mechanism of IBD, as well as the relationship between UC and CD.

Identifying predictors of low health-related quality of life among patients with inflammatory bowel disease: comparison between Crohn's disease and ulcerative colitis with disease duration

AIM

To identify predictors of low health-related quality of life among patients with inflammatory bowel disease and make a comparison between Crohn's disease and ulcerative colitis with disease duration.

BACKGROUND

Studies have shown that patients with inflammatory bowel disease rate their health-related quality of life lower, as compared with a general population.

DESIGN

Survey.

METHODS

In this study, 197 patients in remission were included and divided into a Crohn's disease group and an ulcerative colitis group. Each group was also divided into separate groups whether the patients had short disease duration or long disease duration. Generic instruments, combined with disease-specific questionnaires, were used for measuring health-related quality of life.

RESULTS

The analysis showed a non-significant effect for diagnosis, but a significant effect for disease duration showing that the patients with short disease duration had lower scores of health-related quality of life compared with patients with long disease duration. A significant interaction between diagnosis and disease duration was also revealed.

CONCLUSION

Patients with longer disease duration experienced a better health-related quality of life than patients with short disease duration. Patients with Crohn's disease and short disease duration have the lowest health-related quality of life and are in greatest need of education and support.

RELEVANCE TO CLINICAL PRACTICE

It is important to identify which patients' are in the greatest need of education and support.

The role of oral hygiene in inflammatory bowel disease

BACKGROUND

The 'hygiene hypothesis' suggests that a reduction in the microbial exposure due to improved health measures has contributed to an immunological imbalance in the intestine and increased the incidence of autoimmune diseases such as inflammatory bowel diseases (IBD). Accordingly, we investigated associations between oral hygiene practices and IBD.

METHODS

We developed and administered a multiple choice questionnaire to evaluate oral hygiene and dental care practices of 137 subjects (83 with IBD and 54 healthy controls).

RESULTS

Of the 83 IBD cases, 31% had ulcerative colitis and 69% had Crohn's disease. For subjects with IBD, the frequency of brushing at disease onset was significantly higher than in controls (P=0.005). Also, the frequency of use of dental floss and breath freshener at disease onset was significantly higher in IBD patients (P=0.005 and<0.001, respectively). Also, patients with IBD more frequently visited their dentist at disease onset (P<0.001) and continued to visit their dentist more often (P<0.001). IBD cases had a higher frequency of dental complications such as tooth caries (P=0.007), oral ulcers (P=0.04) and dry mouth (P=0.001).

CONCLUSIONS

These findings suggest that oral hygiene practices may cause alterations in the flora of the oral mucosa, which causes imbalance in the gut microbiome (dysbiosis), and thereby contributes to the pathogenesis of IBD. Conversely, the increased frequency of dental problems in IBD patients might be due, at least in part, to alterations in oral flora or to their disease.

Inflammatory bowel disease: Established and evolving considerations on its etiopathogenesis and therapy

Modern studies of inflammatory bowel disease (IBD) pathogenesis have been pursued for about four decades, a period of time where the pace of progress has been steadily increasing. This progress has occurred in parallel with and is largely due to developments in multiple basic scientific disciplines that range from population and social studies, genetics, microbiology, immunology, biochemistry, cellular and molecular biology, and DNA engineering. From this cumulative and constantly expanding knowledge base the fundamental pillars of IBD pathogenesis appear to have been identified and consolidated during the last couple of decades. Presently there is a general consensus among basic IBD investigators that both Crohn's disease (CD) and ulcerative colitis (UC) are the result of the combined effects of four basic components: global changes in the environment, the input of multiple genetic variations, alterations in the intestinal microbiota, and aberrations of innate and adaptive immune responses. There is also agreement on the conclusion that none of these four components can by itself trigger or maintain intestinal inflammation. A combination of various factors, and most likely of all four factors, is probably needed to bring about CD or UC in individual patients, but each patient or set of patients seems to have a different combination of alterations leading to the disease. This would imply that different causes and diverse mechanisms underlie IBD, and this could also explain why every patient displays his or her own clinical manifestations and a personalized response to therapy, and requires tailored approaches with different medications. While we are becoming increasingly aware of the importance of this individual variability, we have only a superficial notion of the reasons why this occurs, as hinted by the uniqueness of the genetic background and of the gut flora in each person. So, we are apparently facing the paradox of having to deal with the tremendous complexity of the mechanisms responsible for chronic intestinal inflammation in the setting of each patient's individuality in the response to this biological complexity. This obviously poses considerable challenges to reaching a full understanding of IBD pathogenesis, but being aware of the difficulties is the first step in finding answers to them.

Diminished macrophage apoptosis and reactive oxygen species generation after phorbol ester stimulation in Crohn's disease

BACKGROUND

Crohn's Disease (CD) is a chronic relapsing disorder characterized by granulomatous inflammation of the gastrointestinal tract. Although its pathogenesis is complex, we have recently shown that CD patients have a systemic defect in macrophage function, which results in the defective clearance of bacteria from inflammatory sites.

METHODOLOGY/PRINCIPAL FINDINGS

Here we have identified a number of additional macrophage defects in CD following diacylglycerol (DAG) homolog phorbol-12-myristate-13-acetate (PMA) activation. We provide evidence for decreased DNA fragmentation, reduced mitochondrial membrane depolarization, impaired reactive oxygen species production, diminished cytochrome c release and increased IL-6 production compared to healthy subjects after PMA exposure. The observed macrophage defects in CD were stimulus-specific, as normal responses were observed following p53 activation and endoplasmic reticulum stress.

CONCLUSION

These findings add to a growing body of evidence highlighting disordered macrophage function in CD and, given their pivotal role in orchestrating inflammatory responses, defective apoptosis could potentially contribute to the pathogenesis of CD.

Phylogenetic analysis of inflammatory bowel disease associated Escherichia coli and the fimH virulence determinant

BACKGROUND

Evidence supports the role of adherent invasive Escherichia coli (AIEC) in the pathogenesis of inflammatory bowel disease (IBD). However, little is known about the phylogenetic structure and origin of this group of bacteria. Multi-locus sequence typing (MLST), and fimH sequence analysis were performed to elucidate the phylogenetic relationships between E. coli strains isolated from IBD tissue.

METHODS

Thirty-six E. coli isolated from IBD patients and healthy individuals were used. MLST analysis of the adk, fumC, gyrB, icd, mdh, purA, and recA housekeeping genes was performed. The fimH gene was also sequenced and phylogenetically analyzed. Biochemical profiling of strains were performed using the API 20 E system.

RESULTS

MLST analysis distinguished 9 new alleles and 11 new sequence types, nearly all of which belonged to IBD isolates. E. coli isolated from IBD patients were more likely to be grouped into separate clonal clusters by eBURST analysis of allelic profiles (P = 0.02). Sequencing of fimH placed putative AIEC strains into the same cluster with the uro-pathogenic E. coli CFT073 and the avian-pathogenic E. coli O1:K1:H7.

CONCLUSIONS

MLST analysis suggested that E. coli isolated from IBD patients did not evolve from a unique ancestral background. Together with the fimH sequence we conclude that AIEC represent a group of bacteria that have been able to take advantage of an "IBD microenvironment" and likely shares common genes with extraintestinal pathogens like uro-pathogenic CFT073 and avian-pathogenic O1:K1:H7 E. coli. Future research should focus on genes that are unique to AIEC.

The immunopathogenesis of Crohn's disease: a three-stage model

The pathogenesis of Crohn's disease (CD) has remained an enigma for at least a century. There was considerable optimism that genetic linkage and genome-wide association (GWA) studies had identified genes causally responsible. However, the realisation that these genes make a relatively minor contribution to the development of CD has led to the acceptance of a 'missing heritability'. In contrast to the weak genetic effects, patients with CD almost without exception exhibit a gross phenotype, namely a profound systemic failure of the acute inflammatory response. This results in markedly delayed clearance of bacteria from the tissues, leading to local chronic granulomatous inflammation and compensatory adaptive immunological changes, as well as constitutional symptoms.

Crohn's disease and early exposure to domestic refrigeration

Background

Environmental risk factors playing a causative role in Crohn's Disease (CD) remain largely unknown. Recently, it has been suggested that refrigerated food could be involved in disease development. We thus conducted a pilot case control study to explore the association of CD with the exposure to domestic refrigeration in childhood.

Methodology/Principal Findings

Using a standard questionnaire we interviewed 199 CD cases and 207 age-matched patients with irritable bowel syndrome (IBS) as controls. Cases and controls were followed by the same gastroenterologists of tertiary referral clinics in Tehran, Iran. The questionnaire focused on the date of the first acquisition of home refrigerator and freezer. Data were analysed by a multivariate logistic model. The current age was in average 34 years in CD cases and the percentage of females in the case and control groups were respectively 48.3% and 63.7%. Patients were exposed earlier than controls to the refrigerator (X2 = 9.9, df = 3, P = 0.04) and refrigerator exposure at birth was found to be a risk factor for CD (OR = 2.08 (95% CI: 1.01–4.29), P = 0.05). Comparable results were obtained looking for the exposure to freezer at home. Finally, among the other recorded items reflecting the hygiene and comfort at home, we also found personal television, car and washing machine associated with CD.

Conclusion

This study supports the opinion that CD is associated with exposure to domestic refrigeration, among other household factors, during childhood.

Nutrition and Crohn's disease: an update of print and Web-based guidance

This article reviews the role of nutrition in Crohn's disease, one of the inflammatory bowel diseases. In addition to presenting a comprehensive review of the state-of-the-evidence on nutritional risks and nutritional therapies in Crohn's disease, and making specific nutrient recommendations, this article includes a list of Web-based resources, including websites, blogs, newsletters, and multimedia podcasts that can be utilized by patients and healthcare providers alike to learn more about the etiology, pathophysiology, and nutritional management of Crohn's disease.

What is the role of the metabolic activity of the gut microbiota in inflammatory bowel disease? Probing for answers with stable isotopes

The pathogenesis of inflammatory bowel disease remains obscure. However, there has been increasing interest in the role of the gut microbiota, focusing in particular on the "unculturable majority" of luminal and mucosal bacteria, which until recently have been difficult to study owing to the technical challenges of identification and elucidating function. Bacterial components and metabolites have been implicated in signalling to host immune systems and regulating inflammatory responses. Although the rapid expansion in techniques of molecular microbiology has increased our understanding of bacterial diversity, the tools to assess bacterial metabolic activity, and to link the 2, lag behind. Stable isotope probing is a powerful technique to link the metabolic activity and diversity of "unculturable" bacteria through isotopic labelling of biomarkers such as DNA and RNA. Progression of current stable isotope probing methodology with high-resolution oligonucleotide 16s rRNA probe technology and high precision liquid chromatographic isotope ratio mass spectrometry may facilitate application in human microbial ecology. Progress towards stable isotope probing use in vivo, in concert with other advances in bacterial metabolome analysis, will lead to the development of a dynamic picture of the metabolic activity and diversity of intestinal bacteria in inflammatory bowel disease. Such insights will, over time, lead to fuller understanding of inflammatory bowel disease pathogenesis and the development of targeted therapies to reverse the "dysbiosis" that precedes disease relapse.

Probiotics and prebiotics in inflammatory bowel disease: microflora 'on the scope'

The intestinal microflora is a large bacterial community that colonizes the gut, with a metabolic activity equal to an organ and various functions that affect the physiology and pathology of the host's mucosal immune system. Intestinal bacteria are useful in promotion of human health, but certain components of microflora, in genetically susceptible individuals, contribute to various pathological disorders, including inflammatory bowel disease. Clinical and experimental observations indicate an imbalance in protective and harmful microflora components in these disorders. Manipulation of gut flora to enhance its protective and beneficial role represents a promising field of new therapeutic strategies of inflammatory bowel disease. In this review, we discuss the implication of gut flora in the intestinal inflammation that justifies the role of probiotics and prebiotics in the prevention and treatment of inflammatory bowel disease and we address the evidence for therapeutic benefits from their use in experimental models of colitis and clinical trials.

Diet and ulcerative colitis

Dietary factors have been considered as a possible risk factor for ulcerative colitis (UC). Red meat, high fat intake and high protein intake are associated with development and relapse in UC. On the other hand, probiotics, fish oil and dietary fiber have shown good efficacy in the treatment of UC. This paper reviews the updated data on the role of dietary factors in the pathogenesis and treatment of UC.

Effect of Scutellariae Radix extract on experimental dextran-sulfate sodium-induced colitis in rats

AIM: To investigate the effect of Scutellariae Radix extract (SRE) on ulcerative colitis (UC) in rats induced by dextran-sulfate sodium (DSS).

METHODS: Colitis was induced in male Sprague-Dawley (SD) rats (170-180 g) by 4% dextran sulfate sodium (DSS, wt/v; MW 54000) in drinking water for 8 d. The treated rats received 4% DSS and SRE orally (100 mg/kg per day). Control rats received either tap water or SRE only. Macroscopic assessment which included body weight changes, fecal occult blood and stool consistency were determined daily. At the appointed time, the rats were sacrificed and the entire colons were removed. The colon length and the myeloperoxidase (MPO) activity were measured. The severity of colitis was graded by morphological and histological assessments. The ion transport activity of the colonic mucosa was assessed by electrophysiological technique.

RESULTS: Rats treated with oral administration of 4% DSS regularly developed clinical and macroscopic signs of colitis. Treatment with SRE relieved the symptoms, including the reduction in body weight, shortening and ulceration of the colon. Administration of SRE also significantly reduced the histological damage induced by DSS. Moreover, the I_SC responses of the colonic mucosa to forskolin were suppressed after the induction of colitis. The stimulated ion transport activity of DSS-rats treated with SRE displayed significant improvement in the secretory responsiveness.

CONCLUSION: SRE was effective in treating acute DSS-induced ulcerative colitis, as gauged by reduced clinical disease, improved macroscopic and histological damage scores, and enhanced recovery of normal colonic secretory function.

Inflammatory bowel diseases: the paediatric gastroenterologist's perspective

Inflammatory bowel diseases (IBDs), including Crohn disease (CD) and ulcerative colitis (UC), often affect children and adolescents. Their diagnosis is based on the integration of clinical, biological, endoscopic, histological and radiological data. The paediatric radiologist may help the clinician in many ways. In children presenting with symptoms compatible with IBD, gut exploration by US may identify those who will benefit from more invasive explorations including endoscopy. During the process of diagnosis, small bowel exploration has a crucial role in differentiating CD from UC and in classifying the disease into subphenotypes. Finally, new imaging methods are useful during patient follow-up for assessing disease activity and for the diagnosis of complications.

Measurement of intestinal mucosal permeability in dogs with lymphocytic-plasmacytic enteritis

Lymphocytic-plasmacytic enteritis (LPE) is a type of canine inflammatory bowel disease (IBD). One of its most probable causes is a defect in the mucosal permeability barrier. In the present study, intestinal permeability in LPE dogs was examinated to evaluate its clinical value. Twenty-nine dogs with LPE diagnosed by clinical and histological examinations were included in this study. Intestinal permeability was evaluated by measuring the ratio of the concentrations of two sugars (lactulose (L) and rhamnose (R)) with different molecular weights in urine samples after oral administration of a solution containing them. Biopsy specimens of duodenum were evaluated according to histological criteria. The urinary L:R ratio in the 29 LPE dogs (1.68 +/- 1.17, mean +/- SD) was significantly higher than that in the 10 healthy control dogs (0.75 +/- 0.38, P<0.01). In the LPE dogs, a weak correlation was observed between the histopathological grading score of the duodenum and the urinary L:R ratio (r=0.408, P<0.05). The urinary L:R ratio in the 20 dogs showing hypoalbuminemia (< 2.5 g/dl) was significantly higher than that in the 9 dogs with normal serum albumin levels > 2.5 g/dl (P<0.01). In conclusion, permeability of the intestinal mucosa as determined by the urinary L:R ratio could be a useful laboratory parameter for evaluating intestinal damage in LPE dogs.

Lymphocyte-dependent and Th2 cytokine-associated colitis in mice deficient in Wiskott-Aldrich syndrome protein

BACKGROUND & AIMS

Controversy exists as to whether patients with inflammatory bowel disease have an underlying immunodeficiency. We have focused on a murine model of the Wiskott-Aldrich syndrome, an immunodeficiency in which autoimmunity can manifest in the form of an inflammatory bowel disease-like illness. Wiskott-Aldrich syndrome protein (WASP) deficiency in mice results in similar clinical features. Herein, we characterized the colitis in WASP-deficient mice.

METHODS

WASP-deficient mice were followed clinically and histologically. Immunologic studies were performed to determine the pathogenic cell population(s), the predominant cytokine expression pattern, and the role of cytokine(s) in colitis pathogenesis.

RESULTS

All WASP-deficient mice develop colitis by 6 months of age. Lymphocytes are required for disease induction, and CD4(+) T cells from WASP-deficient mice are sufficient to induce disease in lymphocyte-deficient hosts. Lamina propria preparations from WASP-deficient mice demonstrated elevations in interferon-gamma, interleukin (IL)-4, and IL-13 levels but decreased IL-6 and no difference in IL-17 expression in comparison with wild-type controls. Treatment with neutralizing antibody to IL-4, but not to interferon-gamma, abrogated colitis development. However, mice deficient in both WASP and IL-4 showed no difference in histologic colitis scores at 24 weeks of age compared with WASP-deficient mice.

CONCLUSIONS

These results demonstrate a critical role for lymphocytes and a relative T helper 2 cytokine predominance in the colitis associated with WASP-deficient mice. This is the only model of colitis with elevated T helper 2 cytokines and aberrant natural regulatory T cell function and is unique in having a human disease counterpart with similar defects.

Cystic fibrosis: a polymicrobial infectious disease

Cystic fibrosis (CF) is the most common lethal genetic disease in the Caucasian population, and should be considered an infectious disease because of the basic pathophysiology. Chronic lower airway infections cause a progressive pathologic deterioration of lung tissue, a decline in pulmonary function and, ultimately, respiratory failure and death in 90% of CF patients. Historically, very few bacterial species have been implicated as principal CF pathogens. However, molecular evidence suggests the presence of a diverse mosaic of bacteria in CF lungs, and infections can be defined as polymicrobial. Here we review the work that supports this concept and we discuss the potential significance of the polymicrobial community in lung pathology. Understanding the dynamics of polymicrobial infections, the interplay between pathogen(s), normal oropharyngeal flora and the host immune system may lead to future advances in the therapeutic management of chronic lung infections.

Crohn's disease and its mucocutaneous involvement

Crohn's disease (CD) is a chronic inflammatory disorder primarily affecting the lower gastrointestinal tract but potentially involving the skin, musculoskeletal system, and eyes. The origin remains unknown, although diverse etiologic agents have been proposed. Characteristic pathologic appearances include the formation of "skip" lesions (discrete regions of inflamed bowel separated by uninvolved mucosae), aphthous ulceration, and fistulation; these signs relate to the presence of an underlying granulomatous transmural inflammation. Cutaneous and oral lesions frequently occur in CD. They may be classified as specific manifestations (in particular, perianal fissures, abscesses, sinuses, and fistulae in ano) with a granulomatous noncaseating inflammation on histologic examination, and nonspecific manifestations (eg, erythema nodosum, neutrophilic dermatoses) with a nonspecific histologic pattern. The diagnosis of CD is based on clinical, endoscopic, radiologic, and histopathologic features. Therapy is mainly aimed at the control of the acute disease and prevention of relapse through the use of mesalazine, corticosteroids, immunosuppressive agents and very recently, anti-tumor necrosis factor-alpha antibodies.

Progress in basic inflammatory bowel disease research

A modern approach to inflammatory bowel disease (IBD) research has been under way for little over one-half century, but only during the last two decades has progress accelerated and finally generated tangible results that have been translated into practical and better therapeutic strategies. The areas where progress has been more evident are those currently believed to be the key components of IBD pathogenesis, and include the environment, genetics, enteric microbiology, and immune reactivity. Progress in these different areas has been somewhat uneven, yielding a better understanding of the mechanisms behind gut inflammation and tissue injury rather than of specific etiological agents or predisposing factors. However, with the rapidly increasing utilization of novel methodological approaches like genetics, genomics, proteomics, and pharmacogenomics, it is reasonable to anticipate that the etiopathogenesis of IBD will be unveiled in the next couple of decades and more definitive, perhaps disease-modifying, approaches will be uncovered and implemented.

Analysis of keratin polypeptides 8 and 19 variants in inflammatory bowel disease

BACKGROUND/AIMS

Keratin-8 (KRT8)-null mice develop spontaneous colitis and predisposition to liver injury. Human studies show that some KRT8 variants predispose to end-stage liver disease and progression and suggest that such variants might associate with UC or CD. We asked whether mutations in KRT8 or KRT19, the major intestinal keratins, are associated with UC/CD.

METHODS

Exonic regions of the KRT8/KRT19 genes were polymerase chain reaction-amplified using genomic DNA from 2 independent groups. Group I included 91 unrelated patients with CD, 93 unrelated patients with UC, and 70 unrelated/unaffected volunteers. KRT8 variants were also tested with pyrosequencing in Group II that included 682 independent nuclear families with both parents and at least 1 CD/UC-affected offspring and 273 unaffected controls. Both cohorts were enriched for familial IBD.

RESULTS

In Group I, KRT19 variants were identified in CD/UC patients within the promoter and exons 1+2, with similar mutation frequencies in the control/CD/UC groups. In contrast, 16 of 184 CD+UC patients harbored KRT8 heterozygous variants involving Gly62-to-Cys and Arg341-to-His and a novel Arg341-to-Cys, which were noted in 4 volunteers (Arg341-to-His) and correlated with extensive UC (P = .005). One family with unaffected parents had 3 pediatric-affected siblings with severe disease, 2 of whom are compound heterozygous (Gly62-to-Cys/Arg341-to-His). However, there was no significant departure from random transmission of the 3 alleles in Group II IBD families.

CONCLUSIONS

KRT8 and KRT19 variants are not overtransmitted or associated with familial IBD, although a potential role in sporadic IBD cannot be excluded. A novel but rare keratin-8 Arg341-to-Cys is identified in IBD patients.