Geographical variability and environmental risk factors in inflammatory bowel disease

Insights into diet-associated oxidative pathomechanisms in inflammatory bowel disease and protective effects of functional amino acids

There has been a substantial rise in the incidence and prevalence of clinical patients presenting with inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis. Accumulating evidence has corroborated the view that dietary factors (particularly diets with high levels of saturated fat or sugar) are involved in the development and progression of IBD, which is predominately associated with changes in the composition of the gut microbiota and an increase in the generation of reactive oxygen species. Notably, the ecological imbalance of the gut microbiome exacerbates oxidative stress and inflammatory responses, leading to perturbations of the intestinal redox balance and immunity, as well as mucosal integrity. Recent findings have revealed that functional amino acids, including L-glutamine, glycine, L-arginine, L-histidine, L-tryptophan, and hydroxyproline, are effectively implicated in the maintenance of intestinal redox and immune homeostasis. These amino acids and their metabolites have oxygen free-radical scavenging and inflammation-relieving properties, and they participate in modulation of the microbial community and the metabolites in the gut. The principal focus of this article is a review of recent advances in the oxidative pathomechanisms of IBD development and progression in relation to dietary factors, with a particular emphasis on the redox and signal transduction mechanisms of host cells in response to unbalanced diets and enterobacteria. In addition, an update on current understanding of the protective effects of functional amino acids against IBD, together with the underlying mechanisms for this protection, have been provided.

λ-carrageenan exacerbates Citrobacter rodentium-induced infectious colitis in mice by targeting gut microbiota and intestinal barrier integrity

For nearly half a century, the scientific community has been unable to agree upon the safety profile of carrageenan (CGN), a ubiquitous food additive. Little is known about the mechanisms by which consumption of CGN aggravates the etiopathogenesis of murine colitis. However, analyses of gut microbiota and intestinal barrier integrity have provided a breakthrough in explaining the synergistic effect of CGN upon colitis. In Citrobacter rodentium-induced infectious murine colitis, inflammation and the clinical severity of gut tissue were aggravated in the presence of λ-CGN. Using fecal transplantation and germ-free mice experiments, we evaluated the role of intestinal microbiota on the pro-inflammatory effect of λ-CGN. Mice with high dietary λ-CGN consumption showed altered colonic microbiota composition that resulted in degradation of the colonic mucus layer, a raised fecal LPS level, and a decrease in the presence of bacterially derived short-chain fatty acids (SCFAs). Mucus layer defects and altered fecal LPS and SCFA levels could be reproduced in germ-free mice by fecal transplantation from CGN-H-fed mice, but not from germ-free CGN-H-fed mice. Our results confirm that λ-CGN may create an environment that favors inflammation by altering gut microbiota composition and gut bacterial metabolism. The present study provides evidence that the "gut microbiota-barrier axis" could be an alternative target for ameliorating the colitis promoting effect of λ-CGN.

Metabolomics activity screening of T cell-induced colitis reveals anti-inflammatory metabolites

[Figure: see text].

Intestinal flora differences between patients with ulcerative colitis of different ethnic groups in China

To determine the differences in intestinal flora between Uygur and Han patients with ulcerative colitis (UC).Microbial diversity and structural composition of fecal bacteria from patients with UC and their matched healthy spouses or first-degree relatives were analyzed using high-throughput sequencing technology.The fecal microbial diversity and abundance index of Uygur patients with UC (UUC) were significantly lower compared with the Uygur normal control group, while there was no significant difference between the Han UC patients (HUC) and the Han normal control group (HN). Compared with their respective control groups, Uygur UC patients and Han UC patients had a different main composition of human intestinal flora (P < .05). The abundance of Burkholderia, Caballeronia, Paraburkholderia in the UUC group were higher compared with the HUC group, while Faecalibacterium, Bifidobacterium, and Blautia in the HUC group were higher than those in the UUC group (P < .05). Veillonella in the UUC group was higher than that in the Uygur normal control group group, while Subdoligranulum and Ruminococcaceae_UCG-002 were significantly lower (P < .05). Prevotella_9 in the HUC group was significantly higher than that in HN group, while Blautia, Anaerostipes, and [Eubacterium]_hallii_group were significantly lower. Moreover, the top 6 species in order of importance were Christensenellaceae_R_7_group, Ruminococcae_ucg_005, Ruminococcae_ucg_010, Ruminococcae_ucg_013, Haemophilus, and Ezakiella.The difference in intestinal microflora structure may be one of the reasons for the clinical heterogeneity between Uygur and Han patients with UC. Christensenellaceae_R_7_group, Ruminococcae_ucg_005, Ruminococcae_ucg_010, Ruminococcae_ucg_013, Haemophilus, and Ezakiella could be used as potential biomarkers for predicting UC.

Decreased Enteric Bacterial Composition and Diversity in South American Crohn's Disease Vary With the Choice of Treatment Strategy and Time Since Diagnosis

BACKGROUND AND AIMS

The symptomology of Crohn's disease [CD], a chronic inflammatory disease of the digestive tract, correlates poorly with clinical, endoscopic or immunological assessments of disease severity. The prevalence of CD in South America is rising, reflecting changes in socio-economic stability. Many treatment options are available to CD patients, including biological agents and corticosteroids, each of which offers variable efficacy attributed to host genetics and environmental factors associated with alterations in the gut microbiota.

METHODS

Based on 16S rRNA gene sequencing and taxonomic differences, we compared the faecal microbial population of Brazilian patients with CD treated with corticosteroid or anti-tumour necrosis factor [anti-TNF] immunotherapy. Faecal calprotectin and plasma sCD14 levels were quantified as markers for local and systemic inflammation, respectively.

RESULTS

Anti-TNF treatment led to an increased relative abundance of Proteobacteria and a decreased level of Bacteroidetes. In contrast, corticoid treatment was associated with an increase in the relative abundance of Actinobacteria, which has been linked to inflammation in CD. Disruption of the faecal microbiota was related to decreased bacterial diversity and composition. Moreover, the choice of clinical regimen and time since diagnosis modulate the character of the resulting dysbiosis.

CONCLUSIONS

Enteric microbial populations in CD patients who have been treated are modulated by disease pathogenesis, local inflammatory microenvironment and treatment strategy. The dysbiosis that remains after anti-TNF treatment due to decreased bacterial diversity and composition abates restoration of the microbiota to a healthy state, suggesting that the identification and development of new clinical treatments for CD must include their capacity to normalize the gut microbiota.

Review article: bugs, inflammation and mood-a microbiota-based approach to psychiatric symptoms in inflammatory bowel diseases

BACKGROUND

Psychiatric co-morbidities including depression and anxiety are common in inflammatory bowel diseases (IBD). Emerging evidence suggests that interactions between the gut microbiota and brain may play a role in the pathogenesis of psychiatric symptoms in IBD.

AIM

To review the literature on microbiota-brain-gut interactions in gut inflammation, psychosocial stress and mental disorders and to discuss the putative mediating role of gut microbiota in the development of psychiatric symptoms or co-morbidities in IBD.

METHODS

A literature search was conducted on Ovid and Pubmed to select relevant animal and human studies reporting an association between IBD, mental disorders and gut microbiota.

RESULTS

Gut microbial alterations are frequently reported in subjects with IBD and with mental disorders. Both have been associated with reduced faecal bacterial diversity, decreased taxa within the phylum Firmicutes and increased Gammaproteobacteria. In animal studies, microbial perturbations induce behavioural changes and modulate inflammation in mice. Anxiety- and depression-like behaviours in animals can be transferred via faecal microbiota. In humans, modulation of the gut microbiota with probiotics is associated with behavioural and mood changes. Recent data show correlations in changes of faecal and mucosal microbiota and psychological distress in patients with IBD independent of disease activity.

CONCLUSION

Both IBD and mental disorders are associated with gut microbial alterations. Preclinical and preliminary human studies have shown a mediating role of the gut microbiota in intestinal inflammation and anxiety, depression and stress. Targeting the gut microbiota may represent a useful therapeutic approach for the treatment of psychiatric co-morbidities in IBD.

Combined Signature of the Fecal Microbiome and Plasma Metabolome in Patients with Ulcerative Colitis

Background

Ulcerative colitis is a chronic, idiopathic inflammatory disease that destroys the colon structure. Nevertheless, the exact pathogenesis is not clear and needs to be fully elucidated.

Material/Methods

Stool and plasma samples were used for 16S ribosomal RNA sequencing and liquid chromatography mass spectrometry, respectively. In addition, we detected the level of trimethylamine N-oxide. Finally, we performed Pearson correlation analysis between the microbiome and the metabolome.

Results

Twenty-three active ulcerative colitis, 25 inactive ulcerative colitis, and 30 control cases were included. Thirty-four significantly different metabolites were found between the active ulcerative colitis and control groups, 38 were found between the inactive ulcerative colitis and control groups, and only 1 was found between the active ulcerative colitis and inactive ulcerative colitis groups. The plasma trimethylamine N-oxide level of the inactive ulcerative colitis and active ulcerative colitis groups was significantly higher than that of the control group. Moreover, we identified significant changes in 24, 18, and 12 bacterial genera for active ulcerative colitis-control, inactive ulcerative colitis-control, and active ulcerative colitis-inactive ulcerative colitis, respectively. Cross-correlation indicated an association between sphingosine 1-phosphate and Roseburia, Klebsiella, and Escherichia-Shigella. Through the pathway analysis, we found sphingolipid metabolism was one of the most significantly increased pathways.

Conclusions

Although levels of trimethylamine N-oxide were higher in ulcerative colitis patients, they did not achieve statistical significance in active ulcerative colitis and inactive ulcerative colitis groups. Sphingosine 1-phosphate was increased in ulcerative colitis patients and there were several microbiota associated with it. Although further study is still needed, sphingosine 1-phosphate will probably become a new target for treatment of ulcerative colitis.

Evaluation of Home Polysomnography Findings, Quality of Sleep, and Fatigue in Inflammatory Bowel Disease: A Case Series

STUDY OBJECTIVES

The pathogenesis of inflammatory bowel disease (IBD) is not well understood, and sleep disorders may be potential triggers for IBD. Thus, an evaluation of the sleep characteristics, fatigue symptoms, and cytokine levels was performed in patients with IBD during periods of active disease and remission.

METHODS

A total of 20 participants presenting with Crohn's disease or ulcerative colitis, with active disease (n = 7) or in remission (n = 13), underwent home polysomnography (H-PSG). Pittsburgh Sleep Quality Index (PSQI) and Modified Fatigue Impact Scale (MFIS) were applied, in addition to the evaluation of interleukin (IL)-6, IL-10, and tumor necrosis factor alpha (TNF-α) serum levels. Exploratory analysis, t test and Mann-Whitney U test were used.

RESULTS

The mean sleep latency in patients with active disease was 133.07 minutes and 106.79 minutes in those in remission. The sleep efficiency and sleep fragmentation in patients with active disease and those in remission were 80.90% and 84.20% (median), and 76.36/min and 69.82/min (mean), respectively, although the H-PSG parameters did not differ between the groups. The PSQI scores indicated poor sleep quality (global score above 5) in all participants with IBD, and the participants with active disease presented more symptoms of fatigue (P = .032). IL-6 and TNF-α average levels were higher in the participants with disease remission, although with a larger dispersion of the data.

CONCLUSIONS

No significant difference in the H-PSG characteristics was observed between the patients with IBD with active disease and those in remission; however, the perception of the participants with IBD showed significant effect on the sleep quality and fatigue symptoms.

Quantifying the effects of aging and urbanization on major gastrointestinal diseases to guide preventative strategies

BACKGROUND

This study aimed to quantify the effects of aging and urbanization on major gastrointestinal disease (liver cirrhosis, hepatitis B, diarrhea, liver cancer, stomach cancer, pancreas cancer, hepatitis C, esophagus cancer, colon/rectum cancer, gastrointestinal ulcers, diabetes, and appendicitis).

METHODS

We accessed 2004 and 2011 mortality statistics from the most developed cities and least developed rural areas in China using a retrospective design. The relative risk of death associated with urbanization and age was quantified using Generalized linear model (the exp.(B) from model is interpreted as the risk ratio; the greater the B, the greater the impact of urbanized factors or aging factor or effect of aging factor with urbanization). The interaction between region (cities and rural areas) and age was considered as indicator to assess role of age in mortality with urbanization.

RESULTS

Greater risk of disease with urbanization were, in ascending order, for diabetes, colon/rectum cancer, hepatitis C and pancreas cancer. Stronger the effect of aging with urbanization were, in ascending order, for stomach cancer, ulcer, liver cancer, colon/rectum cancer, pancreas cancer, diabetes, hepatitis C, appendicitis and diarrhea. When the effects of aging and urbanization on diseases were taken together as the dividing value, we were able to further divide the 12 gastrointestinal diseases into three groups to guide the development of medical strategies.

CONCLUSIONS

It was suggested that mortality rate for most gastrointestinal diseases was sensitive to urbanization and control of external risk factors could lead to the conversion of most gastrointestinal disease.

Combined Dietary Anthocyanins, Flavonols, and Stilbenoids Alleviate Inflammatory Bowel Disease Symptoms in Mice

Dietary polyphenols are associated with a wide range of health benefits, protecting against chronic diseases and promoting healthy aging. Dietary polyphenols offer a complementary approach to the treatment of inflammatory bowel diseases (IBDs), a group of common chronic intestinal inflammation syndromes for which there is no cure. Tomato is widely consumed but its content of polyphenols is low. We developed a tomato variety, Bronze, enriched in three distinct classes of polyphenols: flavonols, anthocyanins, and stilbenoids. Using Bronze tomatoes as a dietary supplement as well as Indigo (high anthocyanins and flavonols), ResTom (high stilbenoids) and wild-type tomatoes, we examined the effects of the different polyphenols on the host gut microbiota, inflammatory responses, and the symptoms of chronic IBD, in a mouse model. Bronze tomatoes significantly impacted the symptoms of IBD. A similar result was observed using diets supplemented with red grape skin containing flavonols, anthocyanins, and stilbenoids, suggesting that effective protection is provided by different classes of polyphenols acting synergistically.

Interactions between Intestinal Microbiota and Host Immune Response in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract. Although the etiology and pathogenesis of IBD remain unclear, both genetic susceptibility and environmental factors are implicated in the initiation and progression of IBD. Recent studies with experimental animal models and clinical patients indicated that the intestinal microbiota is one of the critical environmental factors that influence nutrient metabolism, immune responses, and the health of the host in various intestinal diseases, including ulcerative colitis and Crohn’s disease. The objective of this review is to highlight the crosstalk between gut microbiota and host immune response and the contribution of this interaction to the pathogenesis of IBD. In addition, potential therapeutic strategies targeting the intestinal micro-ecosystem in IBD are discussed.

Cideb Deficiency Aggravates Dextran Sulfate Sodium-induced Ulcerative Colitis in Mice by Exacerbating the Oxidative Burden in Colonic Mucosa

BACKGROUND

Abnormal lipid metabolism is one of many factors that contribute to the development of ulcerative colitis (UC). As a lipid droplet-associated protein, Cideb facilitated the export of lipids from enterocytes and promoted intestinal lipid absorption. We found that Cideb was upregulated in the colonic mucosa of both UC patients and dextran sodium sulfate (DSS)-induced mouse colitis, but its roles in the pathogenesis of UC are still ill-defined.

METHODS

Acute colitis was induced with DSS in Cideb-null and wild-type mice, and the inflammation and oxidative stress were evaluated in the colonic mucosa. Moreover, triglyceride accumulation and oxidative stress were further analyzed in polarized Caco-2 cells with overexpression of Cideb.

RESULTS

Our present data indicated that Cideb-null mice were more susceptible to DSS-induced colitis, and consumption of a high-fat diet exacerbated the deterioration of DSS-induced colitis in Cideb-null mice. Moreover, Cideb deficiency increased the colonic oxidative stress in DSS-treated mice and more significant under a high-fat diet condition. In exploring the mechanism, we found that Cideb deficiency elevated the lipid content in both feces and the colonic mucosa of DSS-treated mice, especially those fed with a high-fat diet. The in vitro evidence proved that Cideb expression reduced triglyceride accumulation and oxidative stress in polarized Caco-2 cells in the presence of oleic acid.

CONCLUSIONS

Our data suggest that Cideb plays a protective role against the development of UC by reducing the lipid accumulation and oxidative damage in the colonic mucosa. Therefore, Cideb could be a potential therapeutic target for UC.

Family history and disease outcomes in patients with Crohn’s disease: A comparison between China and the United States

AIM

To investigate the differences in family history of inflammatory bowel disease (IBD) and clinical outcomes among individuals with Crohn’s disease (CD) residing in China and the United States.

METHODS

We performed a survey-based cross-sectional study of participants with CD recruited from China and the United States. We compared the prevalence of IBD family history and history of ileal involvement, CD-related surgeries and IBD medications in China and the United States, adjusting for potential confounders.

RESULTS

We recruited 49 participants from China and 145 from the United States. The prevalence of family history of IBD was significantly lower in China compared with the United States (China: 4.1%, United States: 39.3%). The three most commonly affected types of relatives were cousin, sibling, and parent in the United States compared with child and sibling in China. Ileal involvement (China: 63.3%, United States: 63.5%) and surgery for CD (China: 51.0%, United States: 49.7%) were nearly equivalent in the two countries.

CONCLUSION

The lower prevalence of familial clustering of IBD in China may suggest that the etiology of CD is less attributed to genetic background or a family-shared environment compared with the United States. Despite the potential difference in etiology, surgery and ileal involvement were similar in the two countries. Examining the changes in family history during the continuing rise in IBD may provide further insight into the etiology of CD.

Diagnostic Delay in Romanian Patients with Inflammatory Bowel Disease: Risk Factors and Impact on the Disease Course and Need for Surgery

BACKGROUND

The epidemiology of inflammatory bowel disease [IBD] in Eastern Europe is poorly understood, particularly with regard to diagnostic delay. Here we investigated the factors leading to delayed diagnosis and the effect of the delay on several disease progression and outcome measures.

METHODS

A total of 1196 IBD cases [682 ulcerative colitis [UC], 478 Crohn's disease [CD], 36 indeterminate colitis] from the Romanian national registry IBDPROSPECT were reviewed. Standard clinical and demographic factors were evaluated as predictors of a long diagnostic delay in both CD and UC. Diagnostic delay was subsequently evaluated as a potential risk factor for bowel stenoses, bowel fistulas, perianal fistulas, perianal surgery, and intestinal surgery in CD patients.

RESULTS

The median diagnostic delay was significantly longer in CD [5 months] than in UC [1 month] patients [p < 0.001]. Compared with 5 months for UC patients, 75% of CD patients were diagnosed within 18 months of symptom onset. In CD patients, extra-ileal location was a protective factor (odds ratio [OR], 0.5; p = 0.03), whereas being an active smoker [OR, 2.09; p = 0.01] and symptom onset during summer [OR, 3.35; p < 0.001] were independent risk factors for a long diagnostic delay [> 18 months]. In UC patients, an age > 40 years was a protective factor [OR, 0.68; p = 0.04] for a long delay. Regarding outcomes, a long diagnostic delay in CD patients positively correlated with bowel stenoses [OR, 3.38; p < 0.01] and any IBD-related surgery [OR, 1.95; p = 0.03] and had a positive trend for intestinal fistulas [OR, 2.64; p = 0.08] and perianal fistulas [OR, 2.9; p = 0.07]. Disease duration since diagnosis positively correlated with bowel stenoses [OR, 1.04; p = 0.04], any IBD-related surgery [OR, 1.04; p = 0.02], and intestinal surgery [OR, 1.07; p < 0.01].

CONCLUSIONS

A long diagnostic delay in IBD correlates with an increased frequency of bowel stenoses and need for IBD-related surgery.

The Demographic and Clinical Characteristics of Ulcerative Colitis in a Northeast Brazilian Population

INTRODUCTION

The purpose of this study was to describe the clinical and demographic characteristics of UC in Bahia, a Brazilian state, and to identify the variables associated with extensive colitis, steroid therapy, immunosuppression, and colectomy.

METHODS

In this cross-sectional study UC patients were interviewed, and additional information was collected from the medical records. Descriptive statistics and multivariate Poisson regression analysis were used.

RESULTS

This study included 267 individuals, the mean age of whom was 39.4 years at diagnosis. There was a predominance of females and left-side colitis. Extensive colitis was positively associated with male gender, diarrhea, weight loss, and a younger age at diagnosis. In contrast, active smoking and a family history of IBD were negatively associated with extensive colitis. Positive associations were observed between steroid therapy and diarrhea, weight loss, urban patients, extraintestinal manifestations (EIMs), and hospitalization. Younger age and weight loss at diagnosis, a family history of IBD, extensive colitis, EIMs, hospitalization, and steroid therapy were all positively associated with immunosuppression. In contrast, Caucasian individuals, smokers, patients with rectal bleeding, and rural patients areas were all observed to have a decreased likelihood of immunosuppression.

CONCLUSIONS

Our results corroborate the association between higher prevalence of extensive colitis and younger age at diagnosis. An association between steroid therapy and clinical presentation at diagnosis was observed. The observation that white individuals and rural patients use less immunosuppressive drugs highlights the need to study the influence of environmental and genetic factors on the behavior of UC in this population.

Classical and recent advances in the treatment of inflammatory bowel diseases

Crohn's disease (CD) and ulcerative colitis (UC) are intestinal disorders that comprise the inflammatory bowel diseases (IBD). These disorders have a significant effect on the quality of life of affected patients and the increasing number of IBD cases worldwide is a growing concern. Because of the overall burden of IBD and its multifactorial etiology, efforts have been made to improve the medical management of these inflammatory conditions. The classical therapeutic strategies aim to control the exacerbated host immune response with aminosalicylates, antibiotics, corticosteroids, thiopurines, methotrexate and anti-tumor necrosis factor (TNF) biological agents. Although successful in the treatment of several CD or UC conditions, these drugs have limited effectiveness, and variable responses may culminate in unpredictable outcomes. The ideal therapy should reduce inflammation without inducing immunosuppression, and remains a challenge to health care personnel. Recently, a number of additional approaches to IBD therapy, such as new target molecules for biological agents and cellular therapy, have shown promising results. A deeper understanding of IBD pathogenesis and the availability of novel therapies are needed to improve therapeutic success. This review describes the overall key features of therapies currently employed in clinical practice as well as novel and future alternative IBD treatment methods.

Review article: evidence-based dietary advice for patients with inflammatory bowel disease

BACKGROUND

The therapeutic effect of enteral nutrition in Crohn's disease (CD) and the epidemiological associations between diet and inflammatory bowel disease (IBD) implicate diet in IBD causation. There is little evidence, however, to support specific dietary changes and patients often receive contradictory advice.

AIM

To review the literature on the impacts of diet on IBD causation and activity to produce guidance based on 'best available evidence'.

METHOD

Review of Medline, Embase and Cochrane databases from 1975 to 2012 using MeSH headings 'crohn's disease' 'ulcerative colitis' 'enteral' 'diet' 'nutrition' 'fatty acid' and 'food additives'.

RESULTS

Enteral nutrition with a formula-defined feed is effective treatment for CD, but approximately 50% of patients relapse within 6 months of return to normal diet. There is no direct evidence of benefit from any other specific dietary modification in CD, but indirect evidence supports recommendation of a low intake of animal fat, insoluble fibre and processed fatty foods containing emulsifiers. Foods tolerated in sustained remission may not be tolerated following relapse. Some evidence supports vitamin D supplementation. In ulcerative colitis (UC), evidence is weaker, but high intakes of meat and margarine correlate with increased UC incidence and high meat intake also correlates with increased likelihood of relapse.

CONCLUSIONS

There is little evidence from interventional studies to support specific dietary recommendations. Nevertheless, people with IBD deserve advice based on 'best available evidence' rather than no advice at all, although dietary intake should not be inappropriately restrictive. Further interventional studies of dietary manipulation are urgently required.