The role of bacteria in the pathogenesis of ulcerative colitis

Gut vascular barrier in the pathogenesis and resolution of Crohn's disease: A novel link from origination to therapy

The gut vascular barrier (GVB) is the deepest layer of the gut barrier. It mainly comprised gut vascular endothelial cells, enteric glial cells, and pericytes. The GVB facilitates nutrient absorption and blocks bacterial translocation through its size-restricted permeability. Accumulating evidence suggests that dysfunction of this barrier correlates with several clinical pathologies including Crohn's disease (CD). Significant progress has been made to elucidate the mechanism of GVB dysfunction and to confirm the participation of disrupted GVB in the course of CD. However, further analyses are required to pinpoint the specific roles of GVB in CD pathogenesis. Many preclinical models and clinical trials have demonstrated that various agents are effective in protecting the GVB integrity and thus providing a potential CD treatment strategy. Through this review, we established a systemic understanding of the role of GVB in CD pathogenesis and provided novel insights for GVB-targeting strategies in CD treatment.

Quantitative analysis of the three gut microbiota in UC and non-UC patients using real-time PCR

BACKGROUND

and study aims: Gastrointestinal microbiota are closely related to the pathogenesis of ulcerative colitis (UC). This study aimed at quantification of F. prausnitzii, Provetella, and Peptostreptococcus in UC and non-UC patients using Real-Time PCR and a new set of primers were also validated for this purpose.

MATERIALS AND METHODS

In this study, the relative abundance of microbial populations between the UC and non-UC subjects were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). DNA extraction from biopsies and polymerase chain reaction (PCR) amplification of bacterial 16S rRNA gene-targeted species-specific primers was performed to detect the anaerobic bacterial species. The qRT-PCR was used to show the relative change in the bacterial populations of F. prausnitzii, Provetella, and Peptostreptococcus in the UC and non-UC subjects.

RESULTS

Our data for detection of the anaerobic intestinal flora showed Faecalibacterium prausnitzii, Provetella and Peptostreptococcus were the predominant microflora in the controls and showed significant differences (p = 0.002, 0.025 and 0.039, respectively). The qRT-PCR analyses of F. prausnitzii, Provetella and Peptostreptococcus were 8.69-, 9.38- and 5.77-higher, respectively, in the control group than in the UC group.

CONCLUSION

The results of this study showed decreased abundance of F. prausnitzii, Provetella and Peptostreptococcus in the intestine of UC patients in comparison to non-UC patients. Quantitative RT-PCR, as a progressive and sensitive method, could be useful for evaluation of bacterial populations in patients with inflammatory bowel diseases to attain appropriate therapeutic strategies.

Development of Very-Early-Onset Inflammatory Bowel Disease After Multiple Early-Life Antibiotic Exposures: A Case Report and Literature Review

The use of antibiotics has increased drastically over the last few decades. Many antibiotics can target the commensal microbiota and promote gut dysbiosis. These alterations contribute to disease onset and exacerbation. Although the etiology of inflammatory bowel disease (IBD) is mostly unknown, it involves a complex interaction among host genetics, microbiota, environmental factors, and aberrant immune responses. Studies have shown a relationship between very-early-onset inflammatory bowel disease (VEO-IBD) and microbiota alterations. The case discussed in this report endorses the current clinical evidence for this interaction. This is an anonymous record review with no identifiers involving a 23-month-old female patient who was brought to the emergency department by her parents due to persistent bloody diarrhea. Eight days before the presentation, she had experienced watery diarrhea that progressed to bloody stools. The patient had a history of acute otitis media, acute enteritis, and right-arm cutaneous abscess, for which she had received multiple antibiotic therapies. Strategies to manipulate the microbiome through diet, probiotics, antibiotics, or fecal microbiota transplantation (FMT) may be used therapeutically to modulate disease activity. A high index of clinical suspicion for VEO-IBD should be maintained for patients with a history of multiple, recurrent antibiotic use. We believe this case report will raise awareness about the issue of early anaerobic antibiotic exposure and help prevent its unnecessary use and, consequently, prevent gut microbiota dysbiosis that can lead to VEO-IBD. Also, our literature review will hopefully prompt clinicians to consider alternative therapeutic options for this patient population, such as rebuilding intestinal microbiota composition to improve VEO-IBD activity.

Advances in Imaging of Inflammation, Fibrosis, and Cancer in the Gastrointestinal Tract

Gastrointestinal disease is prevalent and broad, manifesting itself in a variety of ways, including inflammation, fibrosis, infection, and cancer. However, historically, diagnostic technologies have exhibited limitations, especially with regard to diagnostic uncertainty. Despite development of newly emerging technologies such as optoacoustic imaging, many recent advancements have focused on improving upon pre-existing modalities such as ultrasound, computed tomography, magnetic resonance imaging, and endoscopy. These advancements include utilization of machine learning models, biomarkers, new technological applications such as diffusion weighted imaging, and new techniques such as transrectal ultrasound. This review discusses assessment of disease processes using imaging strategies for the detection and monitoring of inflammation, fibrosis, and cancer in the context of gastrointestinal disease. Specifically, we include ulcerative colitis, Crohn's disease, diverticulitis, celiac disease, graft vs. host disease, intestinal fibrosis, colorectal stricture, gastric cancer, and colorectal cancer. We address some of the most recent and promising advancements for improvement of gastrointestinal imaging, including unique discussions of such advancements with regard to imaging of fibrosis and differentiation between similar disease processes.

Bin1 targeted immunotherapy alters the status of the enteric neurons and the microbiome during ulcerative colitis treatment

Ulcerative colitis (UC) is a common chronic disease of the large intestine. Current anti-inflammatory drugs prescribed to treat this disease have limited utility due to significant side-effects. Thus, immunotherapies for UC treatment are still sought. In the DSS mouse model of UC, we recently demonstrated that systemic administration of the Bin1 monoclonal antibody 99D (Bin1 mAb) developed in our laboratory was sufficient to reinforce intestinal barrier function and preserve an intact colonic mucosa, compared to control subjects which displayed severe mucosal lesions, high-level neutrophil and lymphocyte infiltration of mucosal and submucosal areas, and loss of crypts. A dysbiotic microbiome may lead to UC. We determined the effects of Bin1 mAb on the gut microbiome and colonic neurons and correlated the benefits of immunotherapeutic treatment. In the DSS model, we found that induction of UC was associated with disintegration of enteric neurons and elevated levels of glial cells, which translocated to the muscularis at distinct sites. Further, we characterized an altered gut microbiome in DSS treated mice associated with pathogenic proinflammatory characters. Both of these features of UC induction were normalized by Bin1 mAb treatment. With regard to microbiome changes, we observed in particular, increase in Enterobacteriaceae; whereas Firmicutes were eliminated by UC induction and Bin1 mAb treatment restored this phylum including the genus Lactobacillus. Overall, our findings suggest that the intestinal barrier function restored by Bin1 immunotherapy in the DSS model of UC is associated with an improvement in the gut microbiome and preservation of enteric neurons, contributing overall to a healthy intestinal tract.

Pharmacokinetic and gut microbiota analyses revealed the effect of Lactobacillus acidophilus on the metabolism of Olsalazine in ulcerative colitis rats

Olsalazine is a typical 5-aminosalicylic acid (5-ASA) drug that depends on gut microbiota to liberate its anti-inflammatory moiety 5-ASA in the treatment of ulcerative colitis (UC). In recent decades, 5-ASA drugs combined with probiotics have achieved a better effective treatment for UC. Mechanisms of combination therapy have been widely discussed from a pharmacodynamic perspective. However, it is still unclear whether the better therapeutic efficacy of combination therapy was made by changing the metabolism of 5-ASA drugs in the colon under the regulation of probiotics. In the present study, combined with pharmacokinetic and gut microbiota analyses, we systematically evaluated the potential effect of Lactobacillus acidophilus (L. acidophilus) on the metabolism of Olsalazine at three levels (pharmacokinetic characteristics, metabolic microbiota, and metabolic enzymes) to offer some insights into this issue. As pharmacokinetic results showed, L. acidophilus barely had an influence on the pharmacokinetic parameters of Olsalazine, 5-ASA, and N-Ac-5-ASA. Notably, the colonic exposure of 5-ASA was not affected by L. acidophilus. Gut microbiota results also illustrated that L. acidophilus did not change the total abundance of azoreductase (azoR) and N-acetyltransferase (NAT) associated gut microbiota and enzymes, which are involved in the metabolism of Olsalazine. Both pharmacokinetic and gut microbiota results revealed that L. acidophilus did not increase the colonic exposure of 5-ASA to improve the efficacy of combination therapy. L. acidophilus played its role in UC treatment by regulating gut microbiota composition and amino acid, phenolic acid, oligosaccharide, and peptidoglycan metabolic pathways. There was no potential medication risk of combination therapy of Olsalazine and L. acidophilus. In summary, this research provided strong evidence of medication safety and a comprehensive understanding of therapeutic advantages for combination therapy of probiotics and 5-ASA drugs from the pharmacokinetic and gut microbiota perspectives.

Socializing Models During Lactation Alter Colonic Mucosal Gene Expression and Fecal Microbiota of Growing Piglets

The enrichment of the social environment during lactation alleviates the stress of weaned piglets. It is significant to understand how the enriched social environment improves the weaning stress of piglets. RNA sequencing (RNA-seq) of colonic mucosa, 16S rRNA sequencing of feces, and short-chain fatty acids (SCFAs) of colonic content were used to determine the effects of social contact during lactation. In this study, thirty litter lactating piglets were divided into intermittent social contact (ISC) group that contacted with neighbors intermittently, continuous social contact (CSC) group that contacted with neighbors starting at day (D) 14 after birth, and control (CON) group in which piglets were kept in their original litter. The piglets were weaned at D35 and regrouped at D36. The colonic mucosal RNA-seq, fecal microbes, and SCFAs of colonic contents of 63-day-old piglets were analyzed. The results of RNA-seq showed that compared with the CON group, the pathways of digestion and absorption of minerals, protein, and vitamins of piglets were changed in the ISC group, whereas the pathways of retinol metabolism and nitrogen metabolism in the colonic mucosal were affected and stimulated the immune response in the CSC group. Compared with the CON group, the abundances of pernicious microorganisms (Desulfovibrio, Pseudomonas, Brevundimonas, etc.) in the CSC group and pernicious microorganisms (Desulfovibrio, Neisseria, Sutterella, etc.) and beneficial bacteria (Bifidobacterium, Megamonas, and Prevotella_9) in the ISC group were significantly higher (p < 0.05). The abundances of proinflammatory bacteria (Coriobacteriaceae_unclassified, Coprococcus_3, and Ruminococcus_2) in the CSC group were significantly increased (p < 0.05), but the abundances of SCFAs producing bacteria (Lachnospiraceae_UCG-010, Parabacteroides, Anaerotruncus, etc.) and those of anti-inflammatory bacteria (Eubacterium, Parabacteroides, Ruminiclostridium_9, and Alloprevotella) were significantly reduced (p < 0.05) in the CSC group. Compared with the CON group, the concentrations of microbial metabolites, acetate, and propionate in the colonic contents were reduced (p < 0.05) in the ISC group, whereas the concentration of acetate was reduced (p < 0.05) in the CSC group. Therefore, both ISC and CSC during lactation affected the composition of fecal microbes and changed the expression of intestinal mucosal genes related to nutrient metabolism and absorption of piglets.

Efficacy of Probiotics-Based Interventions as Therapy for Inflammatory Bowel Disease: A Recent Update

Probiotics such as Lactobacillus spp. play an important role in human health as they embark beneficial effect on the human gastrointestinal microflora composition and immune system. Dysbiosis in the gastrointestinal microbial composition has been identified as a major contributor to chronic inflammatory conditions, such as inflammatory bowel disease (IBD). Higher prevalence of IBD is often recorded in most of the developed Western countries, but recent data has shown an increase in previously regarded as lower risk regions, such as Japan, Malaysia, Singapore, and India. Although the IBD etiology remains a subject of speculation, the disease is likely to have developed because of interaction between extrinsic environmental elements; the host’s immune system, and the gut microbial composition. Compared to conventional treatments, probiotics and probiotic-based interventions including the introduction of specific prebiotics, symbiotic and postbiotic products had been demonstrated as more promising therapeutic measures. The present review discusses the association between gut dysbiosis, the pathogenesis of IBD, and risk factors leading to gut dysbiosis. In addition, it discusses recent studies focused on the alteration of the gastrointestinal microbiome as an effective therapy for IBD. The impact of the COVID-19 pandemic and other viral infections on IBD are also discussed in this review. Clinical and animal-based studies have shown that probiotic-based therapies can restore the gastrointestinal microbiota balance and reduce gut inflammations. Therefore, this review also assesses the status quo of these microbial-based therapies for the treatment of IBD. A better understanding of the mechanisms of their actions on modulating altered gut microbiota is required to enhance the effectiveness of the IBD therapeutics.

Gastrointestinal microbiome and Helicobacter pylori: Eradicate, leave it as it is, or take a personalized benefit–risk approach?

Helicobacter pylori (H. pylori) is generally regarded as a human pathogen and a class 1 carcinogen, etiologically related to gastric and duodenal ulcers, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. However, H. pylori can also be regarded as a commensal symbiont. Unlike other pathogenic/ opportunistic bacteria, H. pylori colonization in infancy is facilitated by T helper type 2 immunity and leads to the development of immune tolerance. Fucosylated gastric mucin glycans, which are an important part of the innate and adaptive immune system, mediate the adhesion of H. pylori to the surface of the gastric epithelium, contributing to successful colonization. H. pylori may have beneficial effects on the host by regulating gastrointestinal (GI) microbiota and protecting against some allergic and autoimmune disorders and inflammatory bowel disease. The potential protective role against inflammatory bowel disease may be related to both modulation of the gut microbiota and the immunomodulatory properties of H. pylori. The inverse association between H. pylori and some potentially proinflammatory and/or procarcinogenic bacteria may suggest it regulates the GI microbiota. Eradication of H. pylori can cause various adverse effects and alter the GI microbiota, leading to short-term or long-term dysbiosis. Overall, studies have shown that gastric Actinobacteria decrease after H. pylori eradication, Proteobacteria increase during short-term follow-up and then return to baseline levels, and Enterobacteriaceae and Enterococcus increase in the short-term and interim follow-up. Various gastric mucosal bacteria (Actinomyces, Granulicatella, Parvimonas, Peptostreptococcus, Prevotella, Rothia, Streptococcus, Rhodococcus, and Lactobacillus) may contribute to precancerous gastric lesions and cancer itself after H. pylori eradication. H. pylori eradication can also lead to dysbiosis of the gut microbiota, with increased Proteobacteria and decreased Bacteroidetes and Actinobacteria. The increase in gut Proteobacteria may contribute to adverse effects during and after eradication. The decrease in Actinobacteria, which are pivotal in the maintenance of gut homeostasis, can persist for > 6 mo after H. pylori eradication. Furthermore, H. pylori eradication can alter the metabolism of gastric and intestinal bacteria. Given the available data, eradication cannot be an unconditional recommendation in every case of H. pylori infection, and the decision to eradicate H. pylori should be based on an assessment of the benefit–risk ratio for the individual patient. Thus, the current guidelines based on the unconditional “test-and-treat” strategy should be revised. The most cautious and careful approach should be taken in elderly patients with multiple eradication failures since repeated eradication can cause antibiotic-associated diarrhea, including severe Clostridioides difficile-associated diarrhea and colitis and antibiotic-associated hemorrhagic colitis due to Klebsiella oxytoca. Furthermore, since eradication therapy with antibiotics and proton pump inhibitors can lead to serious adverse effects and/or dysbiosis of the GI microbiota, supplementation of probiotics, prebiotics, and microbial metabolites (e.g., butyrate + inulin) should be considered to decrease the negative effects of eradication.

Effects of fishmeal replacement by black soldier fly on growth performance, digestive enzyme activity, intestine morphology, intestinal flora and immune response of pearl gentian grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)

An 8-week feeding trial was conducted to investigate the influence of partial replacement of fishmeal (FM) by black soldier fly (BSF) (Hermetia illucens) on the growth, distal intestine morphology, intestinal flora, and intestinal immune response of pearl gentian grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Four diets were formulated, 0% (0 g kg^-1), 10% (50 g kg^-1), 20% (100 g kg^-1) and 30% (150 g kg^-1) fishmeal were replaced with BSF, named as FM, BSF10, BSF20, BSF30, severally. The study found that, with the increasing dietary BSF levels, growth and feed conversion ratio of fish decreased significantly (P < 0.05). Chitinase and trypsin activities were significantly increased with increasing dietary BSF levels (P < 0.05). With the increasing dietary BSF levels, distal intestinal muscularis thickness and mucosal fold length decreased significantly (P < 0.05), as well as total abundance of intestinal flora. The relative abundance of four phyla and six genera among the top 20 genera were significantly affected by dietary BSF levels (P < 0.05). With the increasing dietary BSF levels, the mRNA levels of nf-κbem1, r-cel and il-10 up-regulated significantly (P < 0.05). For fish fed BSF30 diet, the mRNA levels of myd88 and tlr22 were significantly higher than fish fed FM diet (P < 0.05). In conclusion, replacement fishmeal with BSF increased activity of digestive enzymes, but negatively affected growth performance and intestinal health of pearl gentian grouper.

A One Health Perspective for Defining and Deciphering Escherichia coli Pathogenic Potential in Multiple Hosts

E. coli is one of the most common species of bacteria colonizing humans and animals. The singularity of E. coli 's genus and species underestimates its multifaceted nature, which is represented by different strains, each with different combinations of distinct virulence factors. In fact, several E. coli pathotypes, or hybrid strains, may be associated with both subclinical infection and a range of clinical conditions, including enteric, urinary, and systemic infections. E. coli may also express DNA-damaging toxins that could impact cancer development. This review summarizes the different E. coli pathotypes in the context of their history, hosts, clinical signs, epidemiology, and control. The pathotypic characterization of E. coli in the context of disease in different animals, including humans, provides comparative and One Health perspectives that will guide future clinical and research investigations of E. coli infections.

The Antioxidant and Anti-Inflammatory Effects of Quercus brantii Extract on TNBS-Induced Ulcerative Colitis in Rats

Objectives

Ulcerative colitis is a common subtype of persistent inflammatory bowel disease with high morbidity consequences. Despite unknown definite pathogenesis, multiple anti-inflammatory medications are used for its treatment. Traditionally, Quercus brantii (QB), mostly available in the Middle East, has been used for gastrointestinal disorders. Other beneficial effects associated with QB include reduction of oxidative stress, inflammations, homeostatic instability, and improvement in clinical conditions.

Materials and Methods

This experimental study was designed to assess the possible therapeutic effects of QB on UC and compare its effects with those of sulfasalazine. Of the 70 Wistar rats clustered in seven groups, ten received only alcohols and sixty were confirmed to be suffering from trinitrobenzene sulfonic acid- (TNBS-) induced colitis. Four groups received different dosages of QB extract via oral and rectal routes, one received sulfasalazine, and the other remaining two groups received nothing. The effects of QB were evaluated by assessing macroscopic and histologic scoring, measuring inflammatory mediators, and determining oxidative stress markers.

Results

Comparing to the untreated TNBS-induced control groups, QB-treated groups showed a dose- and route-dependent improvement comparable with sulfasalazine. Treating rats with QB reduced the microscopic and macroscopic damage, decreased TNF-α, IL-6, NO, MPO activity, and MDA content, increased superoxide dismutase (SOD) activity, and reduced body weight loss.

Conclusions

Our data recommended the anti-inflammatory and antioxidant effects of QB extract in a dose-dependent manner.

Current Trends in the Treatment of Systemic Lupus Erythematosus

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease in mankind. SLE's downregulation of T and B lymphocytes could cause the development of autoantibodies, which in turn attack cell surface, nuclear, and cytoplasmic molecules, creating immune complexes that harm tissues.

OBJECTIVE

The objective of the present review is to evaluate SLE's present therapeutic policies and raise consciousness about the disease.

METHODS

New therapies are rare for SLE. This is due to the complexity of the disease and its various manifestations. Three techniques are used to develop biological treatments for the illness: B-cell modulation, T-cell regulation and cytokine inhibition. This paper reviews the present trends in SLE therapy.

RESULTS

Each arm of the immune system is a prospective therapeutic development target for this disease; it involves B-cells, T-cells, interferon (IFN) and cytokines. To date, only one of these agents is been approved for use against lupus, belimumab which comes under B-cell therapy. Both the innate and the adaptive immune systems are the objectives. Currently, although there is no full SLE remedy, drug therapy can minimize organ injury and control active disease, which relies on immunosuppressants and glucocorticoids.

CONCLUSION

It is possible to access SLE treatment in the form of T-cell, B-cell and anticytokine therapies. In these therapies, antibodies and antigens interactions play a major part. Another medication for treating SLE is the non-steroidal anti-inflammatory drug such as hydroxychloroquine. Glucocorticoids (GCs) are another antiinflammatory treatment that suppresses the growth of cytokines related to inflammation and prevents the recruitment of leukocyte by reducing endothelial cell permeability.

Development of a susceptibility gene based novel predictive model for the diagnosis of ulcerative colitis using random forest and artificial neural network

Ulcerative colitis is a type of inflammatory bowel disease characterized by chronic and recurrent nonspecific inflammation of the intestinal tract. To find susceptibility genes and develop a novel predictive model of ulcerative colitis, two sets of cases and a control group containing the ulcerative colitis gene expression profile (training set GSE109142 and validation set GSE92415) were downloaded and used to identify differentially expressed genes. A total of 781 upregulated and 127 downregulated differentially expressed genes were identified in GSE109142. The random forest algorithm was introduced to determine 1 downregulated and 29 upregulated differentially expressed genes contributing highest to ulcerative colitis occurrence. Expression data of these 30 genes were transformed into gene expression scores, and an artificial neural network model was developed to calculate differentially expressed genes weights to ulcerative colitis. We established a universal molecular prognostic score (mPS) based on the expression data of the 30 genes and verified the mPS system with GSE92415. Prediction results agreed with that of an independent data set (ROC-AUC=0.9506/PR-AUC=0.9747). Our research creates a reliable predictive model for the diagnosis of ulcerative colitis, and provides an alternative marker panel for further research in disease early screening

Lizhong decoction ameliorates ulcerative colitis in mice via modulating gut microbiota and its metabolites

Ulcerative colitis (UC), a kind of inflammatory bowel disease, is generally characterized by chronic, persistent, relapsing, and nonspecific ulceration of the bowel, which is widespread in the world. Although the pathogenesis of UC is multifactorial, growing evidence has demonstrated that gut microbiota and its metabolites are closely related to the development of UC. Lizhong decoction (LZD), a well-known classical Chinese herbal prescription, has been used to clinically treat UC for long time, but its mechanism is not clear. In this study, 16S rRNA gene sequencing combining with untargeted metabolomics profiling was used to investigate how LZD worked. Results indicated that LZD could shape the gut microbiota structure and modify metabolic profiles. The abundance of opportunistic pathogens such as Clostridium sensu stricto 1, Enterobacter, and Escherichia-Shigella correlated with intestinal inflammation markedly decreased, while the levels of beneficial bacteria including Blautia, Muribaculaceae_norank, Prevotellaceae UCG-001, and Ruminiclostridium 9 elevated in various degrees. Additionally, fecal metabolite profiles reflecting microbial activities showed that adenosine, lysoPC(18:0), glycocholic acid, and deoxycholic acid notably decreased, while cholic acid, α-linolenic acid, stearidonic acid, and L-tryptophan significantly increased after LZD treatment. Hence, based on the systematic analysis of 16S rRNA gene sequencing and metabolomics of gut flora, the results provided a novel insight that microbiota and its metabolites might be potential targets for revealing the mechanism of LZD on amelioration of UC.Key Points • The potential mechanism of LZD on the amelioration of UC was firstly investigated.• LZD could significantly shape the structure of gut microbiota.• LZD could notably modulate the fecal metabolic profiling of UC mice. Graphical abstract.

Seasonal changes of circulating 25-hydroxyvitamin D correlate with the lower gut microbiome composition in inflammatory bowel disease patients

Higher probability of the development of Crohn's disease (CD) and ulcerative colitis (UC) as a possible consequence of the north-south gradient has been recently suggested. Living far north or south of the equator is manifested in fluctuation of vitamin D (vitD) levels depending on the season in both healthy and affected individuals. In the present study we investigate the possible link between the seasonal serum vitD level to the microbial composition of the lower gut of Inflammatory Bowel disease (IBD) patients using 16S rRNA sequencing. Decrease of serum vitD level in winter/spring season in a cohort of 35 UC patients and 39 CD patients was confirmed. Low gut microbiota composition of patients with IBD correlated with the serum level of 25(OH)D that directly coupled to seasonal variability of the sunshine in the central European countries. It is supposed to be related to increased abundance of Actinobacteria and Proteobacteria in UC and Actinobacteria, Fusobacteria, Firmicutes and Bacteroidetes in CD. In summer/autumn period, we observed a reduction in abundance of bacterial genera typical for inflammation like Eggerthella lenta, Fusobacterium spp., Bacteroides spp., Collinsella aerofaciens, Helicobacter spp., Rhodococcus spp., Faecalibacterium prausnitzii; and increased abundance of Pediococcus spp. and Clostridium spp. and of Escherichia/Shigella spp.

An Information-Based Approach for Mediation Analysis on High-Dimensional Metagenomic Data

The human microbiome plays a critical role in the development of gut-related illnesses such as inflammatory bowel disease and clinical pouchitis. A mediation model can be used to describe the interaction between host gene expression, the gut microbiome, and clinical/health situation (e.g., diseased or not, inflammation level) and may provide insights into underlying disease mechanisms. Current mediation regression methodology cannot adequately model high-dimensional exposures and mediators or mixed data types. Additionally, regression based mediation models require some assumptions for the model parameters, and the relationships are usually assumed to be linear and additive. With the microbiome being the mediators, these assumptions are violated. We propose two novel nonparametric procedures utilizing information theory to detect significant mediation effects with high-dimensional exposures and mediators and varying data types while avoiding standard regression assumptions. Compared with available methods through comprehensive simulation studies, the proposed method shows higher power and lower error. The innovative method is applied to clinical pouchitis data as well and interesting results are obtained.

TRIM34 attenuates colon inflammation and tumorigenesis by sustaining barrier integrity

Loss of the colonic inner mucus layer leads to spontaneously severe colitis and colorectal cancer. However, key host factors that may control the generation of the inner mucus layer are rarely reported. Here, we identify a novel function of TRIM34 in goblet cells (GCs) in controlling inner mucus layer generation. Upon DSS treatment, TRIM34 deficiency led to a reduction in Muc2 secretion by GCs and subsequent defects in the inner mucus layer. This outcome rendered TRIM34-deficient mice more susceptible to DSS-induced colitis and colitis-associated colorectal cancer. Mechanistic experiments demonstrated that TRIM34 controlled TLR signaling-induced Nox/Duox-dependent ROS synthesis, thereby promoting the compound exocytosis of Muc2 by colonic GCs that were exposed to bacterial TLR ligands. Clinical analysis revealed that TRIM34 levels in patient samples were correlated with the outcome of ulcerative colitis (UC) and the prognosis of rectal adenocarcinoma. This study indicates that TRIM34 expression in GCs plays an essential role in generating the inner mucus layer and preventing excessive colon inflammation and tumorigenesis.

In Vivo Anti Cancer Potential of Pyrogallol in Murine Model of Colon Cancer

Background: Colon cancer is aggressive and it causes 0.5 million deaths per year. Practicing natural medicines for cancer treatment is safer than conventional drugs. World health organization emphasizes on the importance of practicing natural medicines and developing natural product based drugs for cancer treatment. Recently we reported an anti colon cancer activity associated with pyrogallol isolated from medicinal plant Acacia nilotica in HT-29 cells in vitro. To extend our observation in this study we evaluated in vivo colon tumor remission property of acetone extract of A. nilotica (ACE) and pyrogallol. Materials and Methods: In vivo toxicity of ACE and pyrogallol was assessed and In vivo tumor remission activity of ACE and pyrogallol was determined in murine model. Results: Mice were tolerated different doses of ACE and pyrogallol. Tumor size was considerably reduced in pyrogallol treated mice similar to doxorubicin. Tumor bearing mice treated with ACE and pyrogallol showed mild decline in body weight. Conclusion: Pyrogallol was found to be an effective anti colon cancer agent with less toxicity.

Gut microbiome patterns depending on children's psychosocial stress: Reports versus biomarkers

AIM

Chronic stress increases disease vulnerability factors including inflammation, a pathological characteristic potentially regulated by the gut microbiota. We checked the association between the gut microbiome and psychosocial stress in children/adolescents and investigated which stress parameter (negative versus positive emotion, self-report versus parental report, events versus emotions, biomarker cortisol versus parasympathetic activity) is the most relevant indicator herein.

METHODS

Gut microbiome sequencing was completed in fecal samples from 93 Belgian 8-16y olds. Stress measures included negative events, negative emotions, emotional problems reported by parents, happiness, hair cortisol and heart rate variability (pnn50 parameter reflecting parasympathetic activity). Alpha diversity, beta diversity and linear discriminant analysis were the unadjusted analyses. Age, sex, socio-economic status, diet, physical activity, sleep and weight status were adjusted for via a redundancy analysis and differential abundance via zero-inflated negative binomial regression.

RESULTS

High stress as reflected by low pnn50 and more negative events were associated with a lower alpha diversity as indicated by the Simpson index. Happiness and pnn50 showed significant differences between high and low stress groups based on weighted UniFrac distance, and this remained significant after confounder adjustment. Adjusted and unadjusted taxonomic differences were also most pronounced for happiness and pnn50 being associated respectively with 24 OTU (=11.8% of bacterial counts) and 31 OTU (=13.0%). As a general pattern, high stress was associated with lower Firmicutes at the phylum level and higher Bacteroides, Parabacteroides, Rhodococcus, Methanobrevibacter and Roseburia but lower Phascolarctobacterium at genus level. Several genera gave conflicting results between different stress measures e.g. Ruminococcaceae UCG014, Tenericutes, Eubacterium coprostanoligenes, Prevotella 9 and Christensenellaceae R7. Differential results in preadolescents versus adolescents were also evident.

CONCLUSION

Even in this young healthy population, stress parameters were cross-sectionally associated with gut microbial composition but this relationship was instrument specific. Positive emotions and parasympathetic activity appeared the strongest parameters and should be integrated in future microbiota projects amongst other stress measures.

Mulberry juice freeze-dried powder attenuates the disease severity by the maintaining of colon mucosa in mice with DSS-induced acute colitis

This study aimed to evaluate the microbial compositions and gene expression related to inflammation in dextran sodium sulfate (DSS)-induced acute colitis and the effect of mulberry supplementation. Male BALB/c mice received a diet supplemented with mulberry juice freeze-dried powder (MFP) or not for 3 weeks. After 3 weeks, the mice received water containing 5% (w/v) DSS or not for 1 week. The disease activity index score in mice fed MFP was significantly decreased. A significant decrease in Bifidobacterium spp. and the Clostridium perfringens subgroup was observed in mice not fed MFP. The number of goblet cell and NLRP6 expression were observed in mice fed a diet supplemented with MFP compared with mice not fed MFP. These results may indicate that mulberry mitigates DSS-induced acute colitis by a changing the gut microbial flora and by improving mucosal conditions.

The Efficacy of Probiotics, Prebiotic Inulin-Type Fructans, and Synbiotics in Human Ulcerative Colitis: A Systematic Review and Meta-Analysis

Studies of probiotics, fructan-type prebiotics, and synbiotics in patients with ulcerative colitis (UC) show significant heterogeneity in methodology and results. Here, we study the efficacy of such interventions and the reasons for the heterogeneity of their results. Eligible random controlled trials were collected from the PUBMED and SCOPUS databases. A total of 18 placebo-controlled and active treatment-controlled (i.e., mesalazine) studies were selected with a Jadad score ≥ 3, including 1491 patients with UC. Data for prebiotics and synbiotics were sparse and consequently these studies were excluded from the meta-analysis. The UC remission efficacy of probiotics was measured in terms of relative risk (RR) and odds ratio (OR). Significant effects were observed in patients with active UC whenever probiotics containing bifidobacteria were used, or when adopting the US Food and Drug Administration (FDA)-recommended scales (UC Disease Activity Index and Disease Activity Index). By the FDA recommended scales, the RR was 1.55 (CI95%: 1.13–2.15, p-value = 0.007, I² = 29%); for bifidobacteria-containing probiotics, the RR was 1.73 (CI95%: 1.23–2.43, p-value = 0.002, I² = 35%). No significant effects were observed on the maintenance of remission for placebo-controlled or mesalazine-controlled studies. We conclude that a validated scale is necessary to determine the state of patients with UC. However, probiotics containing bifidobacteria are promising for the treatment of active UC.

Probiotic Medilac-S® for the induction of clinical remission in a Chinese population with ulcerative colitis: A systematic review and meta-analysis

AIM

To assess the effects of probiotic Medilac-S® as adjunctive therapy for the induction of remission of ulcerative colitis (UC) in a Chinese population through a systematic review and meta-analysis.

METHODS

A systematic literature search was conducted to find randomized, controlled trials in a Chinese population with at least two study arms - a control arm which receives a conventional, oral aminosalicylate drug, and a treatment arm, which administers the same conventional drug in conjunction with the probiotic Medilac-S® per os. Both English and Chinese databases were searched, including PubMed, EMBASE, Google Scholar, Chinese National Knowledge Infrastructure, Wanfang Data, and VIP Search, and study data was extracted onto standardized abstraction sheets. Meta-analyses were conducted for primary and secondary outcomes of interest using a fixed or random effects model. The primary outcome was the induction of clinical remission and the secondary outcomes included changes in Sutherland index, endoscopic and histological scores, proportion of reported clinical symptoms and adverse events (AEs). For outcomes with sufficient data, the type of conventional drug therapy was also assessed to determine if the effects of combination therapy with Medilac-S® was influenced by drug type. All tests were conducted using a type I error rate of 0.05 and all confidence intervals (CI) were based on a 95% confidence level. Review protocol was uploaded to PROSPERO (CRD42018085658 upon completion).

RESULTS

Fifty-three clinical trials with a total of 3984 participants were identified and included in the review. Medilac-S® adjunctive therapy significantly improved induction of clinical remission (RR = 1.21; 95%CI: 1.18-1.24; P < 0.0001) with the estimated likelihood of effective treatment, on average, 21% higher for those consuming the probiotic. Sutherland index scores showed the control mean was on average 3.10 (CI: 2.41-3.78; P = 0.0428) units greater than the treatment mean, thereby demonstrating significant improvement in participants taking the probiotic. Similarly, a significant difference was seen between the overall reduction of endoscopic and histological scores of control and treatment arm participants, with score decreases in the control groups 0.71 (CI: 0.3537-1.0742) and 1.1 (CI: 0.9189-1.2300) units smaller than treatment group score decreases. The proportion of participants reporting clinical symptoms, (abdominal pain, tenesmus, blood and mucous in stool, and diarrhea) was significantly reduced after combination therapy with Medilac-S® (P < 0.0001) and estimated to be on average 44% (RR = 0.44, CI: 0.32-0.59), 53% (RR = 0.53, CI: 0.38-74), 40% (RR = 0.40, CI: 0.28-0.58) and 47% (RR = 0.47 CI: 0.36-0.42) respectively, of the proportion of individuals reporting the aforementioned symptoms after conventional therapy alone. The risk of AEs was also significantly reduced with adjunctive Medilac-S® therapy. The proportion of individuals in the treatment groups reporting AEs was an estimated 72% of the proportion of individuals in the control groups reporting AEs (RR = 0.72, CI: 0.55-0.94, P = 0.0175). Upon comparing effect means for different drug types in conjunction with Medilac-S®, evidence of significant variability (P < 0.0001) was observed, and sulfasalazine was found to be the most effective drug in both primary and secondary outcomes.

CONCLUSION

Evidence suggests Medilac-S® adjunctive therapy should be considered standard care for UC in a Chinese population because it aids in the induction of clinical remission, improves symptoms of the gastrointestinal tract and reduces risk of AEs.

Molecular profiling of mucosal tissue associated microbiota in patients manifesting acute exacerbations and remission stage of ulcerative colitis

Dysbiosis of intestinal microflora has been postulated in ulcerative colitis (UC), which is characterized by imbalance of mucosal tissue associated bacterial communities. However, the specific changes in mucosal microflora during different stages of UC are still unknown. The aim of the current study was to investigate the changes in mucosal tissue associated microbiota during acute exacerbations and remission stages of UC. The mucosal microbiota associated with colon biopsy of 12 patients suffering from UC (exacerbated stage) and the follow-up samples from the same patients (remission stage) as well as non-IBD subjects was studied using 16S rRNA gene-based sequencing and quantitative PCR. The total bacterial count in patients suffering from exacerbated phase of UC was observed to be two fold lower compared to that of the non-IBD subjects (p = 0.0049, Wilcox on matched-pairs signed rank tests). Bacterial genera including Stenotrophomonas, Parabacteroides, Elizabethkingia, Pseudomonas, Micrococcus, Ochrobactrum and Achromobacter were significantly higher in abundance during exacerbated phase of UC as compared to remission phase. The alterations in bacterial diversity with an increase in the abnormal microbial communities signify the extent of dysbiosis in mucosal microbiota in patients suffering from UC. Our study helps in identifying the specific genera dominating the microbiota during the disease and thus lays a basis for further investigation of the possible role of these bacteria in pathogenesis of UC.

The possible relationship between Campylobacter spp./Arcobacter spp. and patients with ulcerative colitis

BACKGROUND AND AIMS

The role of bacterial infection in the pathogenesis of ulcerative colitis (UC) is under investigation. This study aims to (i) determine the prevalence of Campylobacter spp. and Arcobacter spp. in patients with UC, (ii) identify the antibiotic susceptibility of isolated agents, and (iii) investigate the role of these microorganisms in the pathogenesis and/or activation of UC.

PATIENTS AND METHODS

Eighty patients with UC and 40 healthy individuals were included in the study. Stool samples were used for cultural examination. Direct plating, membrane filtration, and enrichment methods were used for isolation. 16s rRNA sequence analysis was used for definitive identification of isolates that were identified phenotypically.

RESULTS

In the UC group, 20 (25%) patients had proctitis, 40 (50%) patients had left-type involvement, and 20 (25%) patients had extensive involvement. Campylobacter spp. were isolated from four (5%) patients in the UC group and isolates were identified as C. curvus, C. concisus, C. sputorum, and C. jejuni. C. concisus and C. jejuni were found to be resistant to ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole. C. jejuni was also resistant to tetracycline. All samples were negative for Arcobacter spp. The samples from the control group neither showed the presence of Campylobacter spp. nor Arcobacter spp.

CONCLUSION

Given the clinical, endoscopic, and bacteriological examination results, it is believed that Campylobacter spp. are agents that cause flare-up clinically by being superimposed on the primary disease, rather than agents that initiate the disease in patients with UC. Arcobacter spp., which are known to cause acute gastroenteritis, were not found to be associated with UC.

Why is it so difficult to evaluate faecal microbiota transplantation as a treatment for ulcerative colitis?

Faecal microbiota transplantation (FMT) has recently re-emerged as a viable therapeutic option for colonic disorders. Its efficacy has been proved in the treatment of Clostridium difficile infection which has encouraged research into the use of FMT for other disorders involving gut dysbiosis, such as ulcerative colitis (UC), a chronic inflammatory disease characterized by relapsing and remitting colonic inflammation. Although the FMT protocol for C. difficile treatment is well established, there are numerous additional factors to consider when applying FMT to treat inflammatory diseases. Various studies have attempted to address these factors but technical inconsistency between reports has resulted in a failure to achieve clinically significant findings. Case reports of FMT in UC have shown favorable outcomes yet demonstrating these effects on a larger scale has proved difficult. The following review aims to explore these issues and to analyze why they may be hindering the progression of FMT therapy in UC.

TNF-α inhibits SCF, ghrelin, and substance P expressions through the NF-κB pathway activation in interstitial cells of Cajal

Ulcerative colitis is a chronic inflammatory disease of the colon where intestinal motility is disturbed. Interstitial cells of Cajal (ICC) are required to maintain normal intestinal motility. In the present study, we assessed the effect of tumor necrosis factor-alpha (TNF-α) on viability and apoptosis of ICC, as well as on the expression of stem cell factor (SCF), ghrelin, and substance P. ICC were derived from the small intestines of Swiss albino mice. Cell viability and apoptosis were measured using CCK-8 assay and flow cytometry, respectively. ELISA was used to measure the concentrations of IL-1β, IL-6, ghrelin, substance P, and endothelin-1. Quantitative RT-PCR was used to measure the expression of SCF. Western blotting was used to measure the expression of apoptosis-related proteins, interleukins, SCF, and NF-κB signaling pathway proteins. TNF-α induced inflammatory injury in ICC by decreasing cell viability and increasing apoptosis and levels of IL-1β and IL-6. TNF-α decreased the levels of SCF, ghrelin, and substance P, but had no effect on endothelin-1. TNF-α down-regulated expressions of SCF, ghrelin, and substance P by activating the NF-κB pathway in ICC. In conclusion, TNF-α down-regulated the expressions of SCF, ghrelin, and substance P via the activation of the NF-κB pathway in ICC.

Role of oral and gut microbiome in nitric oxide-mediated colon motility

Periodontal disease (PD), a severe form of gum disease, is among the most prevalent chronic infection in humans and is associated with complex microbial synergistic dysbiosis in the subgingival cavity. The immune system of the body interacts with the microbes as the plaque extends and propagates below the gingival sulcus. Once bacteria reach the gingival sulcus, it can enter the blood stream and affect various areas of the human body. The polymicrobial nature of periodontal disease, if left untreated, promotes chronic inflammation, not only within the oral cavity, but also throughout the human body. Alterations seen in the concentrations of healthy gut microbiota may lead to systemic alterations, such as gut motility disorders, high blood pressure, and atherosclerosis. Although gut microbiome has been shown to play a vital role in intestinal motility functions, the role of oral bacteria in this setting remains to be investigated. It is unclear whether oral microbial DNA is present in the large intestine and, if so, whether it alters the gut microbiome. In addition, polybacterial infection induced PD reduced nitric oxide (NO) synthesis and antioxidant enzymes in rodent colon. In this review, we will discuss the interactions between oral and gut microbiome, specifics of how the oral microbiome may modulate the activities of the gut microbiome, and possible ramifications of these alterations.

Raoultella Planticola associated necrotizing appendicitis: A novel case report

INTRODUCTION

Raoultella Planticola is a gram negative, aerobic, rod bacteria found in water and soil and is rarely reported to cause infections in humans. This case study is the first of its kind in reporting R. planticola appendicitis.

PRESENTATION OF CASE

We report a case of a woman presenting with a two-day history of increased weakness, fatigue and anorexia, localized pain to the right lower quadrant, and elevated white blood cell count. CT results demonstrated acute uncomplicated appendicitis which was managed via laparoscopic appendectomy. The patient became febrile on the day of the procedure and was found to have R. planticola bacteremia which was treated with amoxicillin-clavulanate. She was discharged on postoperative day two and reported an unremarkable recovery at her five-week follow-up appointment.

DISCUSSION

R. planticola is a common organism that is rarely, though increasingly, associated with human infection. Interestingly, prior to hospitalization, this patient did not have any risk factors commonly associated with R. planticola infection, such as seafood consumption. However, she may have had gastrointestinal tract colonization with R. planticola prior to onset of appendicitis and appendectomy. Bacteremia likely resulted from micro-perforation of the appendix.

CONCLUSION

Although infection with R. planticola is typically benign when treated appropriately, this pathogen has homology with Klebsiella species, and has the potential to acquire antimicrobial resistance. The case presented here suggests that R. planticola should be considered as a potential source of bacteremia in inflammatory/infectious gastrointestinal tract diseases even in the absence of typical risk factors.

Challenges in the diagnosis of ulcerative colitis with concomitant bacterial infections and chronic infectious colitis

Ulcerative colitis (UC) is a chronic inflammation of the large bowel characterized by diarrhea and a negative stool culture. However, several enteropathogens have been implicated as causative agents in UC. The differentiation between chronic infectious colitis (IC) and UC with concurrent infection is difficult owing to their similar clinical presentations. The study aimed to explore the presentations and diagnostic clues that enable differentiation between UC with concomitant infections and chronic IC. The study included 17 UC patients with a bacterial infection and 46 with chronic IC. The UC patients (47 ± 19 years) were younger than the chronic IC patients (58 ± 20 years) (P = 0.022). Bloody diarrhea was more common in UC than in chronic IC (58.8% vs 10.9%, P < 0.001). Previous antibiotic usage was a risk factor for chronic IC (5.9% vs 32.6%, P = 0.031). Malignancy was a common comorbidity of chronic IC (5.9% vs 34.8%, P = 0.022). UC patients had lower antibiotic response rates than chronic IC patients (60.0% vs 87.2%, P = 0.026). Aeromonas species and Clostridium difficile were common in both groups. Histological features of cryptitis and crypt abscess were useful in the diagnosis of UC (P = 0.052 and P = 0.016, respectively). Bloody diarrhea in a young adult, decreased response to antibiotic treatment, and results of endoscopy with biopsy are important features in the diagnosis of UC with bacterial infection.

Reliable Biomarker discovery from Metagenomic data via RegLRSD algorithm

Background

Biomarker detection presents itself as a major means of translating biological data into clinical applications. Due to the recent advances in high throughput sequencing technologies, an increased number of metagenomics studies have suggested the dysbiosis in microbial communities as potential biomarker for certain diseases. The reproducibility of the results drawn from metagenomic data is crucial for clinical applications and to prevent incorrect biological conclusions. The variability in the sample size and the subjects participating in the experiments induce diversity, which may drastically change the outcome of biomarker detection algorithms. Therefore, a robust biomarker detection algorithm that ensures the consistency of the results irrespective of the natural diversity present in the samples is needed.

Results

Toward this end, this paper proposes a novel Regularized Low Rank-Sparse Decomposition (RegLRSD) algorithm. RegLRSD models the bacterial abundance data as a superposition between a sparse matrix and a low-rank matrix, which account for the differentially and non-differentially abundant microbes, respectively. Hence, the biomarker detection problem is cast as a matrix decomposition problem. In order to yield more consistent and solid biological conclusions, RegLRSD incorporates the prior knowledge that the irrelevant microbes do not exhibit significant variation between samples belonging to different phenotypes. Moreover, an efficient algorithm to extract the sparse matrix is proposed. Comprehensive comparisons of RegLRSD with the state-of-the-art algorithms on three realistic datasets are presented. The obtained results demonstrate that RegLRSD consistently outperforms the other algorithms in terms of reproducibility performance and provides a marker list with high classification accuracy.

Conclusions

The proposed RegLRSD algorithm for biomarker detection provides high reproducibility and classification accuracy performance regardless of the dataset complexity and the number of selected biomarkers. This renders RegLRSD as a reliable and powerful tool for identifying potential metagenomic biomarkers.

Consistent metagenomic biomarker detection via robust PCA

BACKGROUND

Recent developments of high throughput sequencing technologies allow the characterization of the microbial communities inhabiting our world. Various metagenomic studies have suggested using microbial taxa as potential biomarkers for certain diseases. In practice, the number of available samples varies from experiment to experiment. Therefore, a robust biomarker detection algorithm is needed to provide a set of potential markers irrespective of the number of available samples. Consistent performance is essential to derive solid biological conclusions and to transfer these findings into clinical applications. Surprisingly, the consistency of a metagenomic biomarker detection algorithm with respect to the variation in the experiment size has not been addressed by the current state-of-art algorithms.

RESULTS

We propose a consistency-classification framework that enables the assessment of consistency and classification performance of a biomarker discovery algorithm. This evaluation protocol is based on random resampling to mimic the variation in the experiment size. Moreover, we model the metagenomic data matrix as a superposition of two matrices. The first matrix is a low-rank matrix that models the abundance levels of the irrelevant bacteria. The second matrix is a sparse matrix that captures the abundance levels of the bacteria that are differentially abundant between different phenotypes. Then, we propose a novel Robust Principal Component Analysis (RPCA) based biomarker discovery algorithm to recover the sparse matrix. RPCA belongs to the class of multivariate feature selection methods which treat the features collectively rather than individually. This provides the proposed algorithm with an inherent ability to handle the complex microbial interactions. Comprehensive comparisons of RPCA with the state-of-the-art algorithms on two realistic datasets are conducted. Results show that RPCA consistently outperforms the other algorithms in terms of classification accuracy and reproducibility performance.

CONCLUSIONS

The RPCA-based biomarker detection algorithm provides a high reproducibility performance irrespective of the complexity of the dataset or the number of selected biomarkers. Also, RPCA selects biomarkers with quite high discriminative accuracy. Thus, RPCA is a consistent and accurate tool for selecting taxanomical biomarkers for different microbial populations.

REVIEWERS

This article was reviewed by Masanori Arita and Zoltan Gaspari.

Acute severe ulcerative colitis: from pathophysiology to clinical management

Ulcerative colitis is a common chronic inflammatory disease of the colon and rectum, resulting from a dysregulated immune response towards intraluminal antigens in a genetically predisposed host. The disease has a varying extent and severity. Approximately 20% of patients with ulcerative colitis experience a severe flare during the course of their disease, requiring hospitalization. Acute severe ulcerative colitis (ASUC) is potentially a life-threatening condition that requires early recognition, hospitalization, correction of body fluids and electrolytes, and nutritional support if needed. Superimposed bacterial or viral infections need to be excluded and thromboprophylaxis should be started. Intravenous corticosteroids are the first-line treatment for this condition. Rescue treatment with ciclosporin or infliximab is indicated in patients who do not sufficiently respond to corticosteroids after 3-5 days, with close monitoring of the patients' symptoms, serum C-reactive protein and albumin levels. If medical therapy fails, timely colectomy should be performed to prevent critical complications. In this article, we review all relevant aspects of ASUC, from its pathophysiological background to modern management in clinical practice.

The dual role of Escherichia coli in the course of ulcerative colitis

Background

This study examines the dual role of Escherichia coli in the course of ulcerative colitis (UC). The intestinal microbiota is considered to play an important role in UC pathogenesis, but how E. coli contributes to inflammation in UC is still unknown. On the one hand, we demonstrated that there was a significant increase in the number of E. coli at the sites of inflammation in patients with UC, which can lead to immune system activation, whilst, on the other hand, E. coli may contribute to the resolution of inflammatory reactions since E. coli can inhibit hydroxyl radical formation by eliminating substrates of the Fenton reaction, by assimilating ferrous iron (Fe²⁺) and inducing the decomposition of hydrogen peroxide (H₂O₂). On this way, E. coli may affect the initiation and/or prolongation of remission stages of UC.

Methods

Ten E. coli strains were isolated from the colonic mucosa of patients in the acute phase of UC. Using PCR, we examined the presence of genes encoding catalases (katG and katE) and proteins participating in iron acquisition (feoB, fepA, fhuA, fecA, iroN, fyuA, and iutA) in these E. coli strains. To determine if iron ions influence the growth rate of E. coli and its ability to decompose H₂O₂, we grew E. coli in defined culture media without iron (M9(-)) or with ferrous ions (M9(Fe²⁺)). Expression levels of genes encoding catalases were examined by real-time PCR.

Results

All investigated E. coli strains had catalase genes (katG, katE), genes coding for receptors for Fe²⁺ (feoB) and at least one of the genes responsible for iron acquisition related to siderophores (fepA, fhuA, fecA, iroN, fyuA, iutA). E. coli cultured in M9(Fe²⁺) grew faster than E. coli in M9(-). The presence of Fe²⁺ in the media contributed to the increased rate of H₂O₂ decomposition by E. coli and induced katG gene expression.

Conclusions

E. coli eliminates substrates of the Fenton reaction by assimilating Fe²⁺ and biosynthesizing enzymes that catalyze H₂O₂ decomposition. Thus, E. coli can inhibit hydroxyl radical formation, and affects the initiation and/or prolongation of remission stages of UC.

Fecal microbiota transplantation in gastrointestinal disease: 2015 update and the road ahead

At its height, the Clostridium difficile infection epidemic caused approximately 7000 infections and 300 deaths per day in the USA. Fecal microbiota transplantation (FMT) has demonstrated extraordinary clinical resolution, C. difficile infection cure rates of over 90%, and low recurrence. In tandem with the rise of FMT, the gastrointestinal microbiome has emerged as a 'vital' organ armed with a wealth of microbe 'soldiers' more powerful than known antibiotics. FMTs' reputation has diffused into many new 'indications' yet these appear to be merely the tip of the iceberg when considering its potential applications. FMT as a therapeutic tool has evolved from the original format of blended donor stool and moved towards a refined product comprising a myriad of microbial components, presented aesthetically as encapsulated lyophilized powder.

Effects of Cocoa Husk Feeding on the Composition of Swine Intestinal Microbiota

A two-diet/two-period change over experiment was performed to investigate the effects of cocoa husks, as a source of dietary fiber and polyphenols, on pig intestinal microbial composition. Six pigs were fed a conventional cereal-based diet or a diet obtained by substitution of 7.5% of the conventional diet with cocoa husks for 3 weeks. Experimental diets were isoproteic and isoenergetic. At the end of each 3 week testing period, samples of fresh feces were collected and analyzed for microbial composition by fluorescence in situ hybridization. Cocoa husks did not affect feed intake, weight gain, and feed efficiency. Analysis of fecal microbial populations, grouped by phyla, showed a decrease of Firmicutes and an increase of Bacteroidetes in cocoa husk-fed pigs. Particularly, cocoa husks reduced fecal populations of the Lactobacillus-Enterococcus group and Clostridium histolyticum and increased the Bacteroides-Prevotella group and Faecalibacterium prausnitzii, suggesting a potential for cocoa husks in the improvement of intestinal microbial balance.

Diets enriched with cranberry beans alter the microbiota and mitigate colitis severity and associated inflammation

Common beans are rich in phenolic compounds and nondigestible fermentable components, which may help alleviate intestinal diseases. We assessed the gut health priming effect of a 20% cranberry bean flour diet from two bean varieties with differing profiles of phenolic compounds [darkening (DC) and nondarkening (NDC) cranberry beans vs. basal diet control (BD)] on critical aspects of gut health in unchallenged mice, and during dextran sodium sulfate (DSS)-induced colitis (2% DSS wt/vol, 7 days). In unchallenged mice, NDC and DC increased (i) cecal short-chain fatty acids, (ii) colon crypt height, (iii) crypt goblet cell number and mucus content and (iv) Muc1, Klf4, Relmβ and Reg3γ gene expression vs. BD, indicative of enhanced microbial activity and gut barrier function. Fecal 16S rRNA sequencing determined that beans reduced abundance of the Lactobacillaceae (Ruminococcus gnavus), Clostridiaceae (Clostridium perfringens), Peptococcaceae, Peptostreptococcaceae, Rikenellaceae and Pophyromonadaceae families, and increased abundance of S24-7 and Prevotellaceae. During colitis, beans reduced (i) disease severity and colonic histological damage, (ii) increased gene expression of barrier function promoting genes (Muc1-3, Relmβ, and Reg3γ) and (iii) reduced colonic and circulating inflammatory cytokines (IL-1β, IL-6, IFNγ and TNFα). Therefore, prior to disease induction, bean supplementation enhanced multiple concurrent gut health promoting parameters that translated into reduced colitis severity. Moreover, both bean diets exerted similar effects, indicating that differing phenolic content did not influence the endpoints assessed. These data demonstrate a proof-of-concept regarding the gut-priming potential of beans in colitis, which could be extended to mitigate the severity of other gut barrier-associated pathologies.

White and dark kidney beans reduce colonic mucosal damage and inflammation in response to dextran sodium sulfate

Common beans are a rich source of nondigestible fermentable components and phenolic compounds that have anti-inflammatory effects. We assessed the gut-health-promoting potential of kidney beans in healthy mice and their ability to attenuate colonic inflammation following dextran sodium sulphate (DSS) exposure (via drinking water, 2% DSS w/v, 7 days). C57BL/6 mice were fed one of three isocaloric diets: basal diet control (BD), or BD supplemented with 20% cooked white (WK) or dark red kidney (DK) bean flour for 3 weeks. In healthy mice, anti-inflammatory microbial-derived cecal short chain fatty acid (SCFA) levels (acetate, butyrate and propionate), colon crypt height and colonic Mucin 1 (MUC1) and Resistin-like Molecule beta (Relmβ) mRNA expression all increased in WK- and DK-fed mice compared to BD, indicative of enhanced microbial activity, gut barrier integrity and antimicrobial defense response. During colitis, both bean diets reduced (a) disease severity, (b) colonic histological damage and (c) increased mRNA expression of antimicrobial and barrier integrity-promoting genes (Toll-like Receptor 4 (TLR4), MUC1-3, Relmβ and Trefoil Factor 3 (TFF3)) and reduced proinflammatory mediator expression [interleukin (IL)-1β, IL-6, interferon (IFN)γ, tumor necrosis factor (TNF)α and monocyte chemoattractant protein-1], which correlated with reduced colon tissue protein levels. Further, bean diets exerted a systemic anti-inflammatory effect during colitis by reducing serum levels of IL-17A, IFNγ, TNFα, IL-1β and IL-6. In conclusion, both WK and DK bean-supplemented diets enhanced microbial-derived SCFA metabolite production, gut barrier integrity and the microbial defensive response in the healthy colon, which supported an anti-inflammatory phenotype during colitis. Collectively, these data demonstrate a beneficial colon-function priming effect of bean consumption that mitigates colitis severity.

Functional impacts of the intestinal microbiome in the pathogenesis of inflammatory bowel disease

: The human intestinal microbiome plays a critical role in human health and disease, including the pathogenesis of inflammatory bowel disease (IBD). Numerous studies have identified altered bacterial diversity and abundance at varying taxonomic levels through biopsies and fecal samples of patients with IBD and diseased model animals. However, inconsistent observations regarding the microbial compositions of such patients have hindered the efforts in assessing the etiological role of specific bacterial species in the pathophysiology of IBD. These observations highlight the importance of minimizing the confounding factors associated with IBD and the need for a standardized methodology to analyze well-defined microbial sampling sources in early IBD diagnosis. Furthermore, establishing the linkage between microbiota compositions with their function within the host system can provide new insights on the pathogenesis of IBD. Such research has been greatly facilitated by technological advances that include functional metagenomics coupled with proteomic and metabolomic profiling. This review provides updates on the composition of the microbiome in IBD and emphasizes microbiota dysbiosis-involved mechanisms. We highlight functional roles of specific bacterial groups in the development and management of IBD. Functional analyses of the microbiome may be the key to understanding the role of microbiota in the development and chronicity of IBD and reveal new strategies for therapeutic intervention.

Oral nanotherapeutics: effect of redox nanoparticle on microflora in mice with dextran sodium sulfate-induced colitis

BACKGROUND

Patients with ulcerative colitis (UC) exhibit overproduction of reactive oxygen species (ROS) and imbalance of colonic microflora. We previously developed a novel redox nanoparticle (RNP(O)), which effectively scavenged ROS in the inflamed mucosa of mice with dextran sodium sulfate (DSS)-induced colitis after oral administration. The objective of this study was to examine whether the orally administered RNP(O) changed the colonic microflora in healthy mice and those with colitis.

METHODS

RNP(O) was synthesized by self-assembly of an amphiphilic block copolymer that contains stable nitroxide radicals in hydrophobic side chain via ether linkage. Colitis was induced in mice by supplementing DSS in drinking water for 7 days, and RNP(O) was orally administered daily during DSS treatment. The alterations of fecal microflora during treatment of DSS and RNP(O) were investigated using microbiological assays.

RESULTS

We investigated that RNP(O) did not result in significant changes to the fecal microflora in healthy mice. Although total aerobic and anaerobic bacteria were not significantly different between experimental groups, a remarkable increase in commensal bacteria (Escherichia coli and Staphylococcus sp.) was observed in mice with DSS-induced colitis. Interestingly, orally administered RNP(O) remarkably reduced the rate of increase of these commensal bacteria in mice with colitis.

CONCLUSIONS

On the basis of the obtained results, it was confirmed that the oral administration of RNP(O) did not change any composition of bacteria in feces, which strongly suggests a protective effect of RNP(O) on healthy environments in intestinal microflora. RNP(O) may become an effective and safe medication for treatment of UC.

Analysis of the intestinal lumen microbiota in an animal model of colorectal cancer

Recent reports have suggested that multiple factors such as host genetics, environment and diet can promote the progression of healthy mucosa towards sporadic colorectal carcinoma. Accumulating evidence has additionally associated intestinal bacteria with disease initiation and progression. In order to examine and analyze the composition of gut microbiota in the absence of confounding influences, we have established an animal model of 1, 2-dimethylhydrazine (DMH)-induced colon cancer. Using this model, we have performed pyrosequencing of the V3 region of the 16S rRNA genes in this study to determine the diversity and breadth of the intestinal microbial species. Our findings indicate that the microbial composition of the intestinal lumen differs significantly between control and tumor groups. The abundance of Firmicutes was elevated whereas the abundance of Bacteroidetes and Spirochetes was reduced in the lumen of CRC rats. Fusobacteria was not detected in any of the healthy rats and there was no significant difference in observed Proteobacteria species when comparing the bacterial communities between our two groups. Interestingly, the abundance of Proteobacteria was higher in CRC rats. At the genus level, Bacteroides exhibited a relatively higher abundance in CRC rats compared to controls (14.92% vs. 9.22%, p<0.001). Meanwhile, Prevotella (55.22% vs. 26.19%), Lactobacillus (3.71% vs. 2.32%) and Treponema (3.04% vs. 2.43%), were found to be significantly more abundant in healthy rats than CRC rats (p<0.001, respectively). We also demonstrate a significant reduction of butyrate-producing bacteria such as Roseburia and Eubacterium in the gut microbiota of CRC rats. Furthermore, a significant increase in Desulfovibrio, Erysipelotrichaceae and Fusobacterium was also observed in the tumor group. A decrease in probiotic species such as Ruminococcus and Lactobacillus was likewise observed in the tumor group. Collectively, we can conclude that a significant difference in intestinal bacterial flora exists between healthy rats and CRC rats.

Cooked navy and black bean diets improve biomarkers of colon health and reduce inflammation during colitis

Common beans contain non-digestible fermentable components (SCFA precursors) and phenolic compounds (phenolic acids, flavonoids and anthocyanins) with demonstrated antioxidant and anti-inflammatory potential. The objective of the present study was to assess the in vivo effect of cooked whole-bean flours, with differing phenolic compound levels and profiles, in a mouse model of acute colitis. C57BL/6 mice were fed a 20 % navy bean or black bean flour-containing diet or an isoenergetic basal diet (BD) for 2 weeks before the induction of experimental colitis via 7 d dextran sodium sulphate (DSS, 2 % (w/v) in the drinking-water) exposure. Compared with the BD, both bean diets increased caecal SCFA and faecal phenolic compound concentrations (P< 0·05), which coincided with both beneficial and adverse effects on colonic and systemic inflammation. On the one hand, bean diets reduced mRNA expression of colonic inflammatory cytokines (IL-6, IL-9, IFN-γ and IL-17A) and increased anti-inflammatory IL-10 (P< 0·05), while systemically reduced circulating cytokines (IL-1β, TNFα, IFNγ, and IL-17A, P< 0·05) and DSS-induced oxidative stress. On the other hand, bean diets enhanced DSS-induced colonic damage as indicated by an increased histological injury score and apoptosis (cleaved caspase-3 and FasL mRNA expression) (P< 0·05). In conclusion, bean-containing diets exerted both beneficial and adverse effects during experimental colitis by reducing inflammatory biomarkers both locally and systemically while aggravating colonic mucosal damage. Further research is required to understand the mechanisms through which beans exert their effects on colonic inflammation and the impact on colitis severity in human subjects.

Beauvericin ameliorates experimental colitis by inhibiting activated T cells via downregulation of the PI3K/Akt signaling pathway

Crohn's disease is a common, chronic inflammatory bowel condition characterized by remission and relapse. Accumulating evidence indicates that activated T cells play an important role in this disease. In the present study, we aimed to examine the effect of beauvericin, a natural cyclic peptide, on 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice, which mimics Crohn's disease. Beauvericin significantly reduced weight loss, diarrhea and mortality, accompanied with notable alleviation of macroscopic and microscopic signs. In addition, this compound decreased serum levels of tumor necrosis factor (TNF)-α and interferon (IFN)- γ in a concentration-dependent manner in mice with experimental colitis. These effects of beauvericin are attributed to its inhibition on activated T cells. Flow cytometry and immunoblot assay data showed that beauvericin suppressed T-cell proliferation, activation and IFN-γ-STAT1-T-bet signaling and subsequently led to apoptosis of activated T cells by suppressing Bcl-2 and phosphorylated Bad as well as increasing cleavage of caspase-3, -9, -12 and PARP. Furthermore, inhibition of PI3K/Akt signaling, which was an upstream regulator of cell activation and survival in activated T cells, contributed to the effect of beauvericin. Overall, these results supported beauvericin as a novel drug candidate for the treatment of colonic inflammation mainly by targeting PI3K/Akt in activated T cells.