Intestinal microbiota: The explosive mixture at the origin of inflammatory bowel disease?

Gut microbiota in pathophysiology, diagnosis, and therapeutics of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a multifactorial disease, which is thought to be an interplay between genetic, environment, microbiota, and immune-mediated factors. Dysbiosis in the gut microbial composition, caused by antibiotics and diet, is closely related to the initiation and progression of IBD. Differences in gut microbiota composition between IBD patients and healthy individuals have been found, with reduced biodiversity of commensal microbes and colonization of opportunistic microbes in IBD patients. Gut microbiota can, therefore, potentially be used for diagnosing and prognosticating IBD, and predicting its treatment response. Currently, there are no curative therapies for IBD. Microbiota-based interventions, including probiotics, prebiotics, synbiotics, and fecal microbiota transplantation, have been recognized as promising therapeutic strategies. Clinical studies and studies done in animal models have provided sufficient evidence that microbiota-based interventions may improve inflammation, the remission rate, and microscopic aspects of IBD. Further studies are required to better understand the mechanisms of action of such interventions. This will help in enhancing their effectiveness and developing personalized therapies. The present review summarizes the relationship between gut microbiota and IBD immunopathogenesis. It also discusses the use of gut microbiota as a noninvasive biomarker and potential therapeutic option.

Influence of nonalcoholic fatty liver disease on inflammatory bowel disease hospitalizations in the United States

BACKGROUND

The reported prevalence of nonalcoholic fatty liver disease (NAFLD) in patients with inflammatory bowel disease (IBD) is 32%. We assessed the influence of NAFLD on IBD hospitalizations in the United States (US).

METHODS

We utilized the National Inpatient Sample database, from 2016-2019, to identify the total IBD hospitalizations in the US and we further subdivided them according to the presence or absence of NAFLD. Hospitalization characteristics, comorbidities and outcomes were compared. Statistical significance was set at P<0.05.

RESULTS

There were 1,272,260 IBD hospitalizations in the US, of which 5.04% involved NAFLD. For IBD hospitalizations with NAFLD, the mean age was 50-64 years, and the proportion of males was 46.97%. IBD hospitalizations with NAFLD had a lower proportion of African Americans (8.7% vs. 11.38%, P<0.001). Comorbidities such as hypertension (50.34% vs. 44.04%, P<0.001) and obesity (18.77% vs. 11.81%, P<0.001) were significantly higher in the NAFLD cohort. Overall, based on the Charlson Comorbidity Index, patients with NAFLD had a higher number of comorbidities (52.77% vs. 20.66%, P<0.001). Mortality was higher in the NAFLD compared to the non-NAFLD cohort (3.14% vs. 1.44%, P<0.001). Patients with NAFLD also incurred significantly higher hospital charges ($69,536 vs. $55,467, p<0.001) and had a longer mean length of stay (6.10 vs. 5.27 days, P<0.001) compared to the cohort without NAFLD. Complications and inpatient procedure requirements were also higher in the NAFLD cohort.

CONCLUSION

Our study revealed greater mortality, morbidity, and healthcare resource utilization in patients with IBD who were hospitalized with a concomitant diagnosis of NAFLD.

Bariatric Surgery and Inflammatory Bowel Disease: National Trends and Outcomes Associated with Procedural Sleeve Gastrectomy vs Historical Bariatric Surgery Among US Hospitalized Patients 2009-2020

PURPOSE

The association between bariatric surgery and IBD-related inpatient outcomes is not well characterized. We report, analyze, and compare inpatient trends and outcomes among encounters with a history of bariatric surgery (Hx-MBS) compared to those receiving bariatric surgery during index admission (PR-MBS) admitted from 2009 to 2020.

METHODS

Retrospective cohort design: the 2009-2020 National Inpatient Sample (NIS) databases were used to identify hospital encounters with patients aged ≥ 18 years with a history of MBS (Hx-MBS) or with procedure coding indicating MBS procedure (PR-MBS) according to International Classification of Diseases, Ninth (ICD-9-CM/ ICD-9-PCS) or Tenth Revision (ICD-10-CM/ICD-10-PCS) Clinical Modification/Procedure Coding System during index admission (ICD-9-CM: V4586; ICD-10-CM: Z9884; ICD-9-PR: 4382, 4389; ICD-10-PR: 0DB64Z3, 0DB63ZZ). Pearson χ2 analysis, analysis of variance, multivariable regression analyses, and propensity matching on independent variables were conducted to analyze significant associations between variables and for primary outcome inflammatory bowel disease-related admission, and secondary outcomes: diagnosis of nonalcoholic steatohepatitis, nonalcoholic fatty liver disease, or chronic mesenteric ischemia during admission.

RESULTS

We identified 3,365,784 (76.20%) Hx-MBS hospitalizations and 1,050,900 hospitalizations with PR-MBS (23.80%). Propensity score matching analysis demonstrated significantly higher odds of inflammatory bowel disease, and chronic mesenteric ischemia for Hx-MBS compared to PR-MBS, and significantly lower odds of nonalcoholic steatohepatitis and nonalcoholic fatty liver disease for Hx-MBS compared to PR-MBS.

CONCLUSION

In our study, Hx-MBS was associated with significantly increased odds of inflammatory bowel disease and other GI pathologies compared to matched controls. The mechanism by which this occurs is unclear. Additional studies are needed to examine these findings.

Orally Administered Diosgenin Alleviates Colitis in Mice Induced by Dextran Sulfate Sodium through Gut Microbiota Modulation and Short-Chain Fatty Acid Generation

Diosgenin (DIO) is a kind of steroid sapogenin derived from natural plants. It exerts strong anti-infection, antiallergy, antiviral, and antishock pharmacological properties. In this article, the protective effects of DIO against dextran sulfate sodium (DSS)-induced colitis in mice were researched. Compared with the 2.5% DSS treatment group, 15 mg/kg body weight of diosgenin alleviated colitis disease, evidenced by the increased body weight, the decrease in the disease activity index, and the histological scores. Furthermore, 16S rRNA high-throughput sequencing results demonstrated that DIO improved the colon homeostasis through modulating the gut microbiota, including increases in the relative abundance of several probiotic bacteria, such as Prevotellaceae (from 1.4% to 5.8%), Lactobacillus (from 12.3% to 29.7%), Mucispirillum (from 0.07% to 0.49%), and decreases in the pathogenic bacteria, such as Streptococcus (from 1.6% to 0.6%) and Pseudomonadaceae (from 0.004% to 0%). In addition, the concentration of gut microbial metabolites, total short-chain fatty acids (SCFAs), acetic acid, and propionic acid were significantly increased after DIO supplementation. In conclusion, our findings suggested that DIO attenuates DSS-induced colitis in mice by means of modulating imbalanced gut microbiota and increases in SCFA generation.

Dihydroquercetin supplement alleviates colonic inflammation potentially through improved gut microbiota community in mice

The purpose of the current study was to investigate the effect of dietary dihydroquercetin (DHQ) supplementation on dextran sodium sulfate (DSS)-induced colitis in mice. Mice were given DHQ supplementation (3 g kg^-1) throughout the study, starting 14 days prior to DSS treatment for 1 week followed by 2 days without DSS. The results showed that dietary DHQ supplementation restored DSS-induced disease activity index (DAI), colon length and histopathology scores of the colon tissue. Additionally, supplementation with DHQ reduced the pro-inflammatory cytokine levels, and enhanced the level of IL-10 in the serum. qPCR results indicated that DHQ supplementation significantly downregulated IL-1β, IL-6, and TNF-α, and upregulated IL-10 gene mRNA expression. Western blot results proved that DHQ supplementation upregulated ZO-1 and occludin levels. Using amplicon sequencing technology, 16S rRNA sequencing results showed that DHQ supplementation increased the fecal Firmicutes/Bacteroidetes ratio and the relative abundance of Lactobacillus and Dubosiella, and decreased the relative abundance of Bacteroidetes. Additionally, DHQ supplementation restored the decreased fecal acetic acid and butyric acid concentrations in DSS-induced colitis mice. Besides, Spearman's correlation analysis showed that Dubosiella was positively correlated with the butyric acid level and Bacteroidetes was positively correlated with the mRNA expression of IL-1β and IL-6. Both Lactobacillus and Dubosiella showed a negative correlation with the mRNA expression of IL-1β, IL-6, and TNF-α, and Dubosiella was positively correlated with IL-10. In summary, it was found that DHQ supplementation alleviated DSS-induced colitis which may be potentially associated with altered fecal microbiota communities in mice.

Molecular and Pathophysiological Links between Metabolic Disorders and Inflammatory Bowel Diseases

Despite considerable epidemiological evidence indicating comorbidity between metabolic disorders, such as obesity, type 2 diabetes, and non-alcoholic fatty liver disease, and inflammatory bowel diseases (IBD), such as Crohn’s disease and ulcerative colitis, as well as common pathophysiological features shared by these two categories of diseases, the relationship between their pathogenesis at molecular levels are not well described. Intestinal barrier dysfunction is a characteristic pathological feature of IBD, which also plays causal roles in the pathogenesis of chronic inflammatory metabolic disorders. Increased intestinal permeability is associated with a pro-inflammatory response of the intestinal immune system, possibly leading to the development of both diseases. In addition, dysregulated interactions between the gut microbiota and the host immunity have been found to contribute to immune-mediated disorders including the two diseases. In connection with disrupted gut microbial composition, alterations in gut microbiota-derived metabolites have also been shown to be closely related to the pathogeneses of both diseases. Focusing on these prominent pathophysiological features observed in both metabolic disorders and IBD, this review highlights and summarizes the molecular risk factors that may link between the pathogeneses of the two diseases, which is aimed at providing a comprehensive understanding of molecular mechanisms underlying their comorbidity.

The Other Side of Malnutrition in Inflammatory Bowel Disease (IBD): Non-Alcoholic Fatty Liver Disease

Steatohepatitis and hepatobiliary manifestations constitute some of the most common extra-intestinal manifestations of Inflammatory Bowel Disease (IBD). On the other hand, non-alcoholic fatty liver disease (NAFLD) affects around 25% of the world's population and is attracting ever more attention in liver transplant programs. To outline the specific pathways linking these two conditions is a pressing task for 21st-century researchers. We are accustomed to expecting the occurrence of fatty liver disease in obese people, but current evidence suggests that there are several different pathways also occurring in underweight patients. Genetic factors, inflammatory signals and microbiota are key players that could help in understanding the entire pathogenesis of NAFLD, with the aim of defining the multiple expressions of malnutrition. In the current review, we summarize the most recent literature regarding the epidemiology, pathogenesis and future directions for the management of NAFLD in patients affected by IBD.

Impact of 6-Month Exposure to Aerosols From Potential Modified Risk Tobacco Products Relative to Cigarette Smoke on the Rodent Gastrointestinal Tract

Cigarette smoking causes adverse health effects that might occur shortly after smoking initiation and lead to the development of inflammation and cardiorespiratory disease. Emerging studies have demonstrated the role of the intestinal microbiome in disease pathogenesis. The intestinal microbiome is susceptible to the influence of environmental factors such as smoking, and recent studies have indicated microbiome changes in smokers. Candidate modified risk tobacco products (CMRTP) are being developed to provide substitute products to lower smoking-related health risks in smokers who are unable or unwilling to quit. In this study, the ApoE^–/– mouse model was used to investigate the impact of cigarette smoke (CS) from the reference cigarette 3R4F and aerosols from two CMRTPs based on the heat-not-burn principle [carbon-heated tobacco product 1.2 (CHTP 1.2) and tobacco heating system 2.2 (THS 2.2)] on the intestinal microbiome over a 6-month period. The effect of cessation or switching to CHTP 1.2 after 3 months of CS exposure was also assessed. Next-generation sequencing was used to evaluate the impact of CMRTP aerosols in comparison to CS on microbiome composition and gene expression in the digestive tract of mice. Our analyses highlighted significant gene dysregulation in response to 3R4F exposure at 4 and 6 months. The findings showed an increase in the abundance of Akkermansiaceae upon CS exposure, which was reversed upon cessation. Cessation resulted in a significant decrease in Akkemansiaceae abundance, whereas switching to CHTP 1.2 resulted in an increase in Lactobacillaceae abundance. These microbial changes could be important for understanding the effect of CS on gut function and its relevance to disease pathogenesis via the microbiome.

Highlighting the Relevance of Gut Microbiota Manipulation in Inflammatory Bowel Disease

Two different conditions are included in inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC), being distinguished by chronic recurrence of gut inflammation in persons that are genetically predisposed and subjected to environmental causative factors. The normal structure of the gut microbiome and its alterations in IBD were defined in several microbial studies. An important factor in the prolonged inflammatory process in IBD is the impaired microbiome or "dysbiosis". Thus, gut microbiome management is likely to be an objective in IBD treatment. In this review, we analyzed the existing data regarding the pathophysiological/therapeutic implications of intestinal microflora in the development and evolution of IBD. Furthermore, the main effects generated by the administration of probiotics, prebiotics, fecal transplantation, and phytochemicals supplementation were analyzed regarding their potential roles in improving the clinical and biochemical status of patients suffering from Crohn's disease (CD) and ulcerative colitis (UC), and are depicted in the sections/subsections of the present paper. Data from the literature give evidence in support of probiotic and prebiotic therapy, showing effects such as improving remission rate, improving macroscopic and microscopic aspects of IBD, reducing the pro-inflammatory cytokines and interleukins, and improving the disease activity index. Therefore, the additional benefits of these therapies should not be ignored as adjuvants to medical therapy.

Study of the therapeutic effect of raw and processed Vladimiriae Radix on ulcerative colitis based on intestinal flora, metabolomics and tissue distribution analysis

BACKGROUND

The intestinal flora imbalance and metabolic disorders are closely related to the pathogenesis of ulcerative colitis (UC). As a commonly used herb for the treatment of gastrointestinal diseases, Vladimiriae Radix (VR) has been used for hundreds of years, and its main active ingredients are costunolide (COS) and dehydrocostus lactone (DEH). Clinical usage habits and previous studies have shown that the processed Vladimiriae Radix (pVR) seems to be more suitable for treating bowel disease than the raw Vladimiriae Radix (rVR), but there is still no relevant comparative study.

PURPOSE

To investigate the therapeutic effect of rVR and pVR on UC by analyzing the intestinal flora, metabolomics and tissue distribution.

METHODS

UC rat models were established to investigate the anti-inflammatory activities of rVR and pVR by enzyme-linked immunosorbent assay (ELISA), and to study their regulation of intestinal flora and metabolism by 16s rRNA gene analysis and Ultra Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS). Moreover, the distribution of COS and DEH in UC mouse tissues were also observed by High Performance Liquid Chromatography Mass Spectrometry (HPLC-MS).

RESULTS

rVR and pVR reduced tissue damage and the levels of TNF-α, IL-6, IL-1β, IL-10, TGF-β and MPO, especially pVR. 16s rRNA gene analysis showed that rVR superior in ameliorating species evenness and restoring the abundance of Lachnospiraceae and Ruminococcaceae, while pVR is better at increasing the richness and the abundance of Prevotellaceae. Metabolomics analysis suggested that rVR regulates the β-alanine, pantothenic acid and coenzyme A biosynthesis, but pVR regulates more abundant metabolic pathways. The tissue distribution data indicated the accumulation of COS and DEH in the gastrointestinal tract.

CONCLUSION

rVR and pVR had obvious therapeutic effect on UC. The potential mechanisms might be regulating abnormal metabolism, affecting the diversity and structure of intestinal flora, and accumulation of COS and DEH in colon.

DSS-induced colitis is associated with adipose tissue dysfunction and disrupted hepatic lipid metabolism leading to hepatosteatosis and dyslipidemia in mice

Considering high prevalence of non-alcoholic fatty liver diseases (NAFLD) in patients with inflammatory bowel disease (IBD), this study aimed to elucidate molecular mechanisms for how intestinal inflammatory conditions are causally linked to hepatic steatosis and dyslipidemia. Both younger and older mice treated with acute or chronic dextran sodium sulfate (DSS) developed colitis, which was evidenced by weight loss, colon length shortening, and elevated disease activity index and inflammation score. They also showed decreased expression of intestinal barrier function-related proteins and elevated plasma lipopolysaccharide level, indicating DSS-induced barrier dysfunction and thereby increased permeability. Interestingly, they displayed phenotypes of hepatic fat accumulation and abnormal blood lipid profiles. This DSS-induced colitis-associated lipid metabolic dysfunction was due to overall disruption of metabolic processes including fatty acid oxidation, lipogenesis, lipolysis, reverse cholesterol transport, bile acid synthesis, and white adipose tissue browning and brown adipose tissue thermogenesis, most of which are mediated by key regulators of energy homeostasis such as FGF21, adiponectin, and irisin, via SIRT1/PGC-1α- and LXRα-dependent pathways. Our study suggests a potential molecular mechanism underlying the comorbidity of NAFLD and IBD, which could provide a key to understanding how the two diseases are pathogenically linked and discovering critical therapeutic targets for their treatment.

Inflammatory bowel disease: tri-directional relationship between microbiota, immune system and intestinal epithelium

Human gut microbiota contributes to host nutrition and metabolism, sustains intestinal cell proliferation and differentiation, and modulates host immune system. The alterations in their composition lead to severe gut disorders, including inflammatory bowel disease (IBD) or inflammatory bowel syndrome (IBS). IBD including ulcerative colitis (UC) and Crohn's disease (CD) are gamut of chronic inflammatory disorders of gut, mediated by complex interrelations among genetic, environmental, and internal factors. IBD has debateable aetiology, however in recent years, exploring the central role of a tri-directional relationship between gut microbiota, mucosal immune system, and intestinal epithelium in pathogenesis is getting the most attention. Increasing incidences and early onset explains the exponential rise in IBD burden on health-care systems. Industrialization, hypersensitivity to allergens, lifestyle, hygiene hypothesis, loss of intestinal worms, and gut microbial composition, explains this shifted rise. Hitherto, the interventions modulating gut microbiota composition, microfluidics-based in vitro gastrointestinal models, non-allergic functional foods, nutraceuticals, and faecal microbiota transplantation (FMT) from healthy donors are some of the futuristic approaches for the disease management.

Effect of rifaximin on gut-lung axis in mice infected with influenza A virus

Gut-lung axis injury is a common finding in patients with respiratory diseases as well as in animal model of influenza virus infection. Influenza virus damages the intestinal microecology while affecting the lungs. Rifaximin, a non-absorbable derivative of rifamycin, is an effective antibiotic that acts by inhibiting bacterial RNA synthesis. This study aimed to determine whether rifaximin-perturbation of the intestinal microbiome leads to protective effects against influenza infection, via the gut-lung axis. Our results showed that influenza virus infection caused inflammation of and damage to the lungs. The expression of tight junction proteins in the lung and colon of H1N1 infected mice decreased significantly, attesting that the barrier structure of the lung and colon was damaged. Due to this perturbation in the gut-lung axis, the intestinal microbiota became imbalanced as Escherichia coli bacteria replicated opportunistically, causing intestinal injury. When influenza infection was treated with rifamixin, qPCR results from the gut showed significant increases in Lactobacillus and Bifidobacterium populations, while Escherichia coli populations markedly decreased. Furthermore, pathology sections and western blotting results illustrated that rifaximin treatment strengthened the physical barriers of the lung-gut axis through increased expression of tight junction protein in the colon and lungs. These results indicated that rifaximin ameliorated lung and intestine injury induced by influenza virus infection. The mechanisms identified were the regulation of gut flora balance and intestinal and lung permeability, which might be related to the regulation of the gut-lung axis. Rifaximin might be useful as a co-treatment drug for the prevention of influenza virus infection.

A phytopharmacological overview of medicinal plants used for prophylactic and treatment of colitis

Inflammatory bowel diseases are chronic diseases that develop on the genetic background. They are characterized by an idiopathic, chronic course and periods of activation and remission. However, genetic and environmental factors are thought to play a role in its pathogenesis. Significant improvements in treatment strategies have been witnessed. Depending on the severity of the disease, mesalamine, immunosuppressants, anti-TNF, anti-integrin, Janus kinase inhibitors, and thiopurines can be used for treatment. However, these treatments have side effects such as headache, dizziness, nausea, loss of appetite, hair loss, gas, vomiting, rash, fever, and decreased white blood cell count. The search for treatment that may be a safer alternative, immunomodulatory, and immunosuppressive therapy has gained importance nowadays. Herbal medicine is preferred to treat a wide range of acute and chronic gastrointestinal diseases, including ulcerative colitis. Preclinical and clinical studies show that plants are promising in terms of their use in treating pathological conditions. The effectiveness of plants in treating ulcerative colitis has been determined. However, more studies are needed to explore the long-term effects of these herbal medicines. The present review presents information on medicinal plants and phytochemicals reported for use or potential of application in ulcerative colitis, a type of inflammatory bowel diseases.

The Close Interplay of Nitro-Oxidative Stress, Advanced Glycation end Products and Inflammation in Inflammatory Bowel Diseases

BACKGROUND

Inflammatory Bowel Disease (IBD) exhibits no defined aetiology. However, factors such as genetic and nitro-oxidative stress are associated with chronic inflammation and IBD progression to Colorectal Cancer (CRC). The present review discusses the association of nitro-oxidative stress, inflammation and Advanced Glycation End products (AGE) and their corresponding receptor (RAGE) in IBD and examines the connection between these factors and nuclear factors, such as Nuclear Factor Kappa B (NF-κB), factorerythroid 2-related factor-2 (Nrf2), and p53 Mutant (p53M).

METHODS

We searched the PubMed, ScienceDirect and Web of Science databases using a combination of the following terms: IBD, CRC, oxidative stress, inflammation, NF-κB, Nrf2, p53M, AGE and RAGE.

RESULTS

Oxidative stress and inflammation activated two cellular pathways, the nuclear expression of pro-inflammatory, pro-oxidant and pro-oncogenic genes based on NF-κB and p53M, which is associated with NF-κB activation, Deoxyribonucleic acid (DNA) damage and the expression of pro-oncogenic genes. Nrf2 stimulates the nuclear expression of enzymatic and non-enzymatic antioxidant systems and anti-inflammatory genes, and is inhibited by chronic oxidative stress, NF-κB and p53M. AGE/RAGE are involved in inflammation progression because RAGE polymorphisms and increased RAGE levels are found in IBD patients. Alterations of these pathways in combination with oxidative damage are responsible for IBD symptoms and the progression to CRC.

CONCLUSION

IBD is an inflammatory and nitro-oxidative stress-based bowel disease. Achieving a molecular understanding of the biochemical events and their complicated interactions will impact basic and applied research, animal models, and clinical trials.

Immunological Tolerance and Function: Associations Between Intestinal Bacteria, Probiotics, Prebiotics, and Phages

Post-birth there is a bacterial assault on all mucosal surfaces. The intestinal microbiome is an important participant in health and disease. The pattern of composition and concentration of the intestinal microbiome varies greatly. Therefore, achieving immunological tolerance in the first 3-4 years of life is critical for maintaining health throughout a lifetime. Probiotic bacteria are organisms that afford beneficial health effects to the host and in certain instances may protect against the development of disease. The potential benefits of modifying the composition of the intestinal microbial cohort for therapeutic benefit is evident in the use in high risks groups such as premature infants, children receiving antibiotics, rotavirus infections in non-vaccinated children and traveler's diarrhea in adults. Probiotics and prebiotics are postulated to have immunomodulating capabilities by influencing the intestinal microbial cohort and dampening the activity of pathobiont intestinal microbes, such as Klebsiella pneumonia and Clostridia perfringens. Lactobacilli and Bifidobacteria are examples of probiotics found in the large intestine and so far, the benefits afforded to probiotics have varied in efficacy. Most likely the efficacy of probiotic bacteria has a multifactorial dependency, namely on a number of factors that include agents used, the dose, the pattern of dosing, and the characteristics of the host and the underlying luminal microbial environment and the activity of bacteriophages. Bacteriophages, are small viruses that infect and lyse intestinal bacteria. As such it can be posited that these viruses display an effective local protective control mechanism for the intestinal barrier against commensal pathobionts that indirectly may assist the host in controlling bacterial concentrations in the gut. A co-operative activity may be envisaged between the intestinal epithelia, mucosal immunity and the activity of bacteriophages to eliminate pathobiots, highlighting the potential role of bacteriophages in assisting with maintaining intestinal homeostasis. Hence bacteriophage local control of inflammation and immune responses may be an additional immunological defense mechanism that exploits bacteriophage-mucin glycoprotein interactions that controls bacterial diversity and abundance in the mucin layers of the gut. Moreover, and importantly the efficacy of probiotics may be dependent on the symbiotic incorporation of prebiotics, and the abundance and diversity of the intestinal microbiome encountered. The virome may be an important factor that determines the efficacy of some probiotic formulations.

Effects of inflammatory bowel disease treatment on the risk of nonalcoholic fatty liver disease: a meta-analysis

BACKGROUND

Epidemiological studies have demonstrated an association between inflammatory bowel disease (IBD) and an increased risk for the development of nonalcoholic fatty liver disease (NAFLD). However, the risk of NAFLD in IBD patients who receive different medical treatments including glucocorticoids, immunomodulators, and tumor necrosis factor-α inhibitors remains unclear. We aimed to assess whether the use of certain IBD medications is associated with the development of NAFLD.

MATERIALS AND METHODS

A systematic review was carried out in Medline, Embase, and Cochrane databases from inception through October 2017 to identify studies that assessed the association between the use of IBD medications and the risk of developing NAFLD. Effect estimates from the individual study were derived and combined using random-effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

Seven observational studies with a total of 1610 patients were enrolled. There was no significant association between the use of IBD medications and the incidence of NAFLD. The pooled odds ratios of NAFLD in patients who use biological agents, immunomodulators, methotrexate, and steroids were 0.85 [95% confidence interval (CI): 0.49-1.46], 1.19 (95% CI: 0.70-2.01), 3.62 (95% CI: 0.48-27.39), and 1.24 (95% CI: 0.85-1.82), respectively. Egger's regression asymmetry test was performed and showed no publication bias.

CONCLUSION

Our study demonstrates no significant association between medications used in the treatment of IBD and the risk of developing NAFLD. The findings of our study suggest a complex, multifactorial relationship between IBD and the development of NAFLD beyond the scope of current pharmacological intervention.

Non-alcoholic fatty liver disease phenotypes in patients with inflammatory bowel disease

Non-alcoholic fatty liver disease (NAFLD) can be detected in up to 33.6% of inflammatory bowel disease (IBD) patients, often in absence of metabolic risk factors. Nevertheless, most of previous studies on such issue were conducted within the IBD population only. The primary aim of this study was to compare clinical and metabolic features of NAFLD in patients with and without IBD (w/o IBD) and to identify specific NAFLD phenotypes within the IBD population. Among 223 NAFLD patients, 78 patients with IBD were younger compared to 145 without (w/o) IBD, were less likely to have altered liver enzymes, had lower mean body weight, smaller waist circumference and lower body mass index (BMI); at the same time, MetS was more prevalent among patients w/o IBD (56.6 vs. 23.1%, p < 0.001). Within IBD population, patients with severe IBD showed more often severe steatosis (S3) at ultrasound (US) (32.1 vs. 16.6%, p = 0.01), compared to mild-to-moderate disease. Independent risk factors for S3 US steatosis in IBD patients at the multivariate logistic regression analysis were: more than 1 IBD relapse per year during disease history (OR 17.3, 95% CI 3.6-84), surgery for IBD (OR 15.1, 95% CI 3.1-73.7) and more extensive intestinal involvement (OR 19.4, 95% CI 3.4-110.9); the ongoing anti-Tumor Necrosis Factor alpha (antiTNFα) therapy was the only independent factor which protect toward the presence of altered liver enzymes (OR 0.15, 95% CI 0-0.8, p = 0.02). In conclusion, NAFLD in IBD patients is different from that in patients w/o IBD, who seem to develop different NAFLD phenotypes according to intestinal disease clinical course. More severe IBD seem to predict the presence of more severe steatosis. Therapy with antiTNFα antibodies could prevent alteration of liver enzymes in such population.

INTESTINAL MICROBIOTA IN DIGESTIVE DISEASES

BACKGROUND

In recent years, especially after the development of sophisticated metagenomic studies, research on the intestinal microbiota has increased, radically transforming our knowledge about the microbiome and its association with health maintenance and disease development in humans. Increasing evidence has shown that a permanent alteration in microbiota composition or function (dysbiosis) can alter immune responses, metabolism, intestinal permeability, and digestive motility, thereby promoting a proinflammatory state. Such alterations can mainly impair the host's immune and metabolic functions, thus favoring the onset of diseases such as diabetes, obesity, digestive, neurological, autoimmune, and neoplastic diseases. This comprehensive review is a compilation of the available literature on the formation of the complex intestinal ecosystem and its impact on the incidence of diseases such as obesity, non-alcoholic steatohepatitis, irritable bowel syndrome, inflammatory bowel disease, celiac disease, and digestive neoplasms.

CONCLUSION:

Alterations in the composition and function of the gastrointestinal microbiota (dysbiosis) have a direct impact on human health and seem to have an important role in the pathogenesis of several gastrointestinal diseases, whether inflammatory, metabolic, or neoplastic ones.

A systems biology analysis protein-protein interaction of NASH and IBD based on comprehensive gene information

AIM

Analysis reconstruction networks from two diseases, IBD and NASH and their relationship, based on systems biology methods.

BACKGROUND

IBD and NASH are two complex diseases, with progressive prevalence and high cost for countries. There are some reports on co-existence of these two diseases. In addition, they have some similar risk factors such as age, obesity, and insulin resistance. Therefore, systems biology approach can help to discover their relationship.

METHODS

DisGeNET and STRING databases were sources of disease genes and constructing networks. Three plugins of Cytoscape software, including ClusterONE, ClueGO and CluePedia, were used to analyze and cluster networks and enrichment of pathways. Based on degree and Betweenness, hubs and bottleneck nodes were defined.

RESULTS

Common genes between IBD and NASH construct a network with 99 nodes. Common genes between IBD and NASH were extracted and imported to STRING database to construct PPI network. The resulting network contained 99 nodes and 333 edges. Five genes were selected as hubs: JAK2, TLR2, TP53, TLR4 and STAT3 and five genes were selected as bottleneck including: JAK2, TP53, AGT, CYP3A4 and TLR4. These genes were hubs in analysis network that was constructed from hubs of NASH and IBD networks.

CONCLUSION

Systems biology methods, specifically PPI networks, can be useful for analyzing complicated related diseases. Finding Hub and bottleneck proteins should be the goal of drug designing and introducing disease markers.

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.

May the assessment of baseline mucosal molecular pattern predict the development of gluten related disorders among microscopic enteritis?

AIM

To evaluate mucosal baseline mRNA expression of tissue transglutaminase 2 (tTG2), interferon gamma (IFNγ), toll-like receptor 2 (TLR2) and Myeloid Differentiation factor 88 (MyD88) in patients with microscopic enteritis (ME).

METHODS

We retrospectively enrolled 89 patients with ME of different etiology, which was defined within a 2-year mean period of follow-up. Baseline histological examination was performed on Hematoxylin-Eosin stained sections and CD3 lymphocyte immunohistochemistry was used for intraepithelial lymphocyte count (IELs). ME was defined according to the criteria of Bucharest Consensus Conference. For each patient, formalin embedded biopsy samples of the duodenum referred to the period of ME diagnosis were retrieved. Real-time polymerase chain reaction (RT-PCR) was used to detect the amount of mRNA coding for tTG2, IFNγ, TLR2 and MyD88, and the quantity was expressed as fold change compared to controls. Control group was represented by duodenal normal specimens from 15 healthy subjects undergoing endoscopy for functional symptoms. Comparisons among continuous variables were performed by One way analysis of variance (ANOVA) and Bonferroni's test. The χ(2) test was used for categorical variables. Pearson's test was used to evaluate correlations. Receiver operating curves were drawn for all four markers to estimate sensitivity and specificity in discriminating the development of CD and GS.

RESULTS

After a period of follow up of 21.7 ± 11.7 mo, the following diagnoses were achieved: gluten related disorders in 48 subjects (31 CD; 17 GS) and non-gluten related ones in 41 (29 Irritable Bowel Syndrome - IBS; 12 Others). CD patients had the highest tTG2 levels (8.3 ± 4.5). The ANOVA plus Bonferroni analysis showed that CD > Other ME > GS = IBS > negative controls. A cut off value of 2.258 was able to discriminate between CD and GS with a sensitivity of 52.94% and a specificity of 87.1%. Additionally, CD patients had the highest IFNγ levels (8.5 ± 4.1). ANOVA plus Bonferroni demonstrated CD > Other ME > GS = IBS > negative controls. A cut off of 1.853 was able to differentiate CD and GS with a sensitivity of 47.06% and a specificity of 96.77%. Patients with non gluten-related causes of ME exhibited the highest TLR2 levels (6.1 ± 1.9) as follows: Other ME > CD = GS = IBS > negative controls. TLR2 was unable to discriminate CD from GS. Patients with CD overexpressed MyD88 levels similarly to non gluten-related causes of DL (7.8 ± 4.9 and 6.7 ± 2.9), thus CD = Other ME > GS = IBS > negative controls. A cut off of 3.722 was able to differentiate CD from GS with a sensitivity of 52.94% and a specificity of 74.19%. IELs count (15-25 and more than 25/100 enterocytes) strongly correlated with mRNA levels of all tested molecules (P < 0.0001).

CONCLUSION

Our results confirm that a single marker is unable to predict a discrimination among ME underlying conditions as well as between CD and GS. Mucosal high levels of tTG and IFNγ mRNA may predict the development of CD more than GS with high specificity, despite an expected low sensitivity. TLR2 does not discriminate the development of CD from GS. MyD88 levels indicate that intestinal permeability is more increased when a severe intestinal damage underlies ME in both gluten related and unrelated conditions. Therefore, the results of the present paper do not seem to show a clear translational value.

Co-existence of non-alcoholic fatty liver disease and inflammatory bowel disease: A review article

Emerging data have highlighted the co-existence of non-alcoholic fatty liver disease (NAFLD) and inflammatory bowel disease; both of which are increasingly prevalent disorders with significant complications and impact on future health burden. Cross-section observational studies have shown widely variable prevalence rates of co-existing disease, largely due to differences in disease definition and diagnostic tools utilised in the studies. Age, obesity, insulin resistance and other metabolic conditions are common risks factors in observational studies. However, other studies have also suggested a more dominant role of inflammatory bowel disease related factors such as disease activity, duration, steroid use and prior surgical intervention, in the development of NAFLD. This suggests a potentially more complex pathogenesis and relationship between the two diseases which may be contributed by factors including altered intestinal permeability, gut dysbiosis and chronic inflammatory response. Commonly used immunomodulation agents pose potential hepatic toxicity, however no definitive evidence exist linking them to the development of hepatic steatosis, nor are there any data on the impact of therapy and prognosis in patient with co-existent diseases. Further studies are required to assess the impact and establish appropriate screening and management strategies in order to allow early identification, intervention and improve patient outcomes.

Incidence and Predictors of Nonalcoholic Fatty Liver Disease by Serum Biomarkers in Patients with Inflammatory Bowel Disease

BACKGROUND

Patients with inflammatory bowel disease (IBD) are at high risk for non-alcoholic fatty liver disease (NAFLD). Longitudinal data on incident NAFLD are lacking. We employed non-invasive methods to study incidence and predictors of NAFLD.

METHODS

This was a retrospective study of IBD patients without known liver disease followed at IBD clinic of McGill University. NAFLD was defined as Hepatic Steatosis Index (HSI) ≥36 and absence of alcohol intake. Advanced liver fibrosis was diagnosed by FIB-4 ≥2.67. Active IBD was defined as partial Mayo score ≥3 for ulcerative colitis, Harvey Bradshaw Index ≥ 5 or flare during follow-up. Kaplan-Meier and Cox regression analyses were used to investigate incidence and predictors of NAFLD development.

RESULTS

Three hundred twenty-one consecutive patients (median age 33.7 yr, 47% males) were observed for a median of 3.2 years (interquartile range 1.5-6). Over 1181.2 persons-year (PY), 108 (33.6%) patients developed NAFLD, accounting for an incidence rate of 9.1/100 PY (95% confidence interval [CI], 7.4-10.9). 7 (2.2%) patients developed advanced liver fibrosis, accounting for an incidence rate of 0.5/100 PY (95% CI, 0.2-1.1). Development of NAFLD was predicted by disease activity (adjusted hazard ratio [aHR] = 1.58; 95% CI, 1.08-2.33, P = 0.02), disease duration (aHR = 1.12; 95% CI, 1.03-1.23, P = 0.01), and prior surgery for IBD (aHR = 1.34; 95% CI, 1.04-1.74, P = 0.02).

CONCLUSIONS

NAFLD is a frequent comorbidity in patients with IBD. These patients can also develop advanced liver fibrosis. Disease activity, duration of IBD and prior surgery are predictors of NAFLD development. This should represent one more incentive to achieve and maintain early clinical remission. Further prospective studies are of interest.

Immunomodulatory Effects of Lactobacillus plantarum Lp62 on Intestinal Epithelial and Mononuclear Cells

Probiotic lactic acid bacteria are known for their ability to modulate the immune system. They have been shown to inhibit inflammation in experiments with animal models, cell culture, and clinical trials. The objective of this study was to elucidate the anti-inflammatory potential of Lactobacillus plantarum Lp62, isolated from cocoa fermentation, in a cell culture model. Lp62 inhibited IL-8 production by Salmonella Typhi-stimulated HT-29 cells and prevented the adhesion of pathogens to these epithelial cells. The probiotic strain was able to modulate TNF-α, IL1-β, and IL-17 secretion by J774 macrophages. J774 activation was reduced by coincubation with Lp62. PBMC culture showed significantly higher levels of CD4⁺CD25⁺ T lymphocytes following treatment with Lp62. Probiotics also induced increased IL-10 secretion by mononuclear cells. L. plantarum Lp62 was able to inhibit inflammatory stimulation in epithelial cells and macrophages and activated a tolerogenic profile in mononuclear cells of healthy donors. These results indicate this strain for a possible application in the treatment or prevention of inflammatory diseases.

Simultaneous purification of DNA and RNA from microbiota in a single colonic mucosal biopsy

BACKGROUND

Nucleic acid purification methods are of importance when performing microbiota studies and especially when analysing the intestinal microbiota as we here find a wide range of different microbes. Various considerations must be taken to lyse the microbial cell wall of each microbe. In the present article, we compare several tissue lysis steps and commercial purification kits, to achieve a joint RNA and DNA purification protocol for the purpose of investigating the microbiota and the microbiota-host interactions in a single colonic mucosal tissue sample.

RESULTS

A further optimised tissue homogenisation and lysis protocol comprising mechanical bead beating, lysis buffer replacement and enzymatic treatment, in combination with the AllPrep DNA/RNA Mini Kit (Qiagen, Hilden, Germany) resulted in efficient and simultaneous purification of microbial and human RNA and DNA from a single mucosal colonic tissue sample.

CONCLUSIONS

The present work provides a unique possibility to study RNA and DNA from the same mucosal biopsy sample, making a direct comparison between metabolically active microbes and total microbial DNA. The protocol also offers an opportunity to investigate other members of a microbiota such as viruses, fungi and micro-eukaryotes, and moreover the possibility to extract data on microbiota and host interactions from one single mucosal biopsy.

The Intestinal Microbiota in Inflammatory Bowel Disease

The intestinal microbiota has important metabolic and host-protective functions. Conversely to these beneficial functions, the intestinal microbiota is thought to play a central role in the etiopathogenesis of inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis), a chronic inflammation of the gut mucosa. Genetic screens and studies in experimental mouse models have clearly demonstrated that IBD can develop due to excessive translocation of bacteria into the bowel wall or dysregulated handling of bacteria in genetically susceptible hosts. In healthy individuals, the microbiota is efficiently separated from the mucosal immune system of the gut by the gut barrier, a single layer of highly specialized epithelial cells, some of which are equipped with innate immune functions to prevent or control access of bacterial antigens to the mucosal immune cells. It is currently unclear whether the composition of the microbial flora or individual bacterial strains or pathogens induces or supports the pathogenesis of IBD. Further research will be necessary to carefully dissect the contribution of individual bacterial species to this disease and to ascertain whether specific modulation of the intestinal microbiome may represent a valuable further option for future therapeutic strategies.

Mechanism of oral virome imbalance in recurrent aphthous ulcer

Recurrent aphthous ulcer (RAU) is the most common oral mucosal disease with complex etiology. Since its pathogenesis is still not completely clear, specific clinical treatment is lacking. With the continuous development of oral micro-ecology, oral microbial population imbalance as an important pathogenesis of RAU is gradually recognized. At present, the research of oral flora imbalance has made some progress, but as the largest member of the oral microbial community, the research of the virome is still under development. In recent years, the rapid development of macro virus genome science and high throughput sequencing technology has led to a breakthrough in oral virome.

Fecal Microbiota Transplantation for Ulcerative Colitis: A Systematic Review and Meta-Analysis

BACKGROUND

Fecal microbiota transplantation (FMT) has been recognized as a novel treatment for ulcerative colitis (UC). However, its efficacy and safety remain unclear.

OBJECTIVE

We conducted this systematic review to assess the efficacy and safety of FMT in UC.

DATA SOURCES

PubMed, EMBASE, Cochrane Central, Web of Science Core Collection, and three other Chinese databases were searched for reports of FMT in UC with clear outcomes.

DATA EXTRACTION AND SYNTHESIS

We estimated pooled rates [with 95% confidence interval (CI)] of clinical remission among 15 cohort studies and clinical response among 16 cohort studies.

RESULTS

Twenty five studies (2 randomized controlled trials, 15 cohort studies, and 8 case studies) with 234 UC patients were included. Overall, 41.58% (84/202) patients achieved clinical remission (CR) and 65.28% (126/193) achieved clinical response. Among the cohort studies, the pooled estimate of patients who achieved CR and clinical response were 40.5% (95% CI 24.7%-58.7%), and 66.1% (95% CI 43.7%-83.0%). Most adverse events were slight and self-resolving. The analyses of gut microbiota in 7 studies showed that FMT could increase microbiota diversity and richness, similarity, and certain change of bacterial composition.

CONCLUSION

FMT provides a promising effect for UC with few adverse events. Successful FMT may be associated with an increase in microbiota diversity and richness, similarity, and certain change of bacterial composition.

Hydradenitis suppurativa and inflammatory bowel disease: An unusual, but existing association

Inflammatory bowel disease (IBD) could be associated with several extra-intestinal manifestations (EIMs) involving musculoskeletal, hepatopancreatobiliary, ocular, renal, and pulmonary systems, as well as the skin. In the last years, hidradenitis suppurativa (HS) is acquiring an increasing interest. IBD, especially Crohn's disease (CD), is among the most reported associated diseases in HS patients. The aim of this paper is to give a brief overview of data showing a possible epidemiologic and pathogenetic association between IBD and HS. We performed a pooled-data analysis of four studies and pooled prevalence of HS in IBD patients was 12.8%, with a 95%CI of 11.7%-13.9%. HS was present in 17.3% of subjects with CD (95%CI: 15.5%-19.1%) and in 8.5% of UC patients (95%CI: 7.0%-9.9%). Some items, especially altered immune imbalance, are generally involved in IBD pathogenesis as well as invoked by HS. Smoking is one of the most relevant risk factors for both disorders, representing a predictor of their severity, despite, actually, there being a lack of studies analyzing a possible shared pathway. A role for inheritance in HS and CD pathogenesis has been supposed. Despite a genetic susceptibility having been demonstrated for both diseases, further studies are needed to investigate a genetic mutual route. Although the pathogenesis of IBD and HS is generally linked to alterations of the immune response, recent findings suggest a role for intestinal and skin microbiota, respectively. In detail, the frequent finding of Staphylococcus aureus and coagulase-negative staphylococci on HS cutaneous lesions suggests a bacterial involvement in disease pathogenesis. Moreover, microflora varies in the different cutaneous regions of the body and, consequently, two different profiles of HS patients have been identified on these bases. On the other hand, it is well-known that intestinal microbiota may be considered as "the explosive mixture" at the origin of IBD despite the exact relationship having not been completely clarified yet. A better comprehension of the role that some bacterial species play in the IBD pathogenesis may be essential to develop appropriate management strategies in the near future. A final point is represented by some similarities in the therapeutic management of HS and IBD, since they may be controlled by immunomodulatory drugs. In conclusion, an unregulated inflammation may cause the lesions typical of both HS and IBD, particularly when they coexist. However, this is still a largely unexplored field.

Current Understanding of Dysbiosis in Disease in Human and Animal Models

Inflammatory bowel disease (IBD) is an intestinal inflammatory condition that affects more than 2 million people in the United States. Although the etiology and pathogenesis of IBD are still largely unknown, dysregulated host/enteric microbial interactions are requisite for the development of IBD. So far, many researchers have tried to identify a precise relationship between IBD and an imbalance of the intestinal microbiota, termed "dysbiosis." Despite extensive efforts, it is still largely unknown about the interplay among microbes, their hosts, and their environments, and whether dysbiosis is a causal factor or an effect of IBD. Recently, deep-sequencing analyses of the microbiota in patients with IBD patients have been instrumental in characterizing the strong association between dysbiosis and IBD development, although it is still unable to identify specific-associated species level changes in most cases. Based on many recent reports, dysbiosis of the commensal microbiota is implicated in the pathogenesis of several diseases, including IBD, obesity, and allergic disorders, in both human and animal models. In this review article, the authors have focused on explaining the multiple types of dysbiosis, as well as dysbiosis-related diseases and potential treatments to apply this knowledge to understand a possible cause and potentially find therapeutic strategies for IBD as well as the other dysbiosis-related diseases.

Current Understanding of Dysbiosis in Disease in Human and Animal Models

Inflammatory bowel disease (IBD) is an intestinal inflammatory condition that affects more than 2 million people in the United States. Although the etiology and pathogenesis of IBD are still largely unknown, dysregulated host/enteric microbial interactions are requisite for the development of IBD. So far, many researchers have tried to identify a precise relationship between IBD and an imbalance of the intestinal microbiota, termed "dysbiosis." Despite extensive efforts, it is still largely unknown about the interplay among microbes, their hosts, and their environments, and whether dysbiosis is a causal factor or an effect of IBD. Recently, deep-sequencing analyses of the microbiota in patients with IBD patients have been instrumental in characterizing the strong association between dysbiosis and IBD development, although it is still unable to identify specific-associated species level changes in most cases. Based on many recent reports, dysbiosis of the commensal microbiota is implicated in the pathogenesis of several diseases, including IBD, obesity, and allergic disorders, in both human and animal models. In this review article, the authors have focused on explaining the multiple types of dysbiosis, as well as dysbiosis-related diseases and potential treatments to apply this knowledge to understand a possible cause and potentially find therapeutic strategies for IBD as well as the other dysbiosis-related diseases.

Gut Bacterial DNA Translocation is an Independent Risk Factor of Flare at Short Term in Patients With Crohn's Disease

OBJECTIVES

We aimed at evaluating bacterial DNA (bactDNA) presence in blood of Crohn's disease (CD) patients in remission as an independent risk factor of flare at 6 months.

METHODS

This is a prospective, multicenter study on CD patients with Crohn's disease activity index (CDAI)<150. The primary end point was time-to-relapse as evaluated by CDAI>150 in the following 6 months. BactDNA in blood, the nucleotide-binding oligomerization domain containing 2 (NOD2) genotype, and serum cytokine levels were determined at baseline.

RESULTS

A total of 288 patients were included. BactDNA was detected in 98 patients (34.0%). A variant-NOD2 genotype was identified in 114 patients (39.6%). Forty patients (14%) relapsed during follow-up. Multivariate survival analysis identified bactDNA as an independent risk factor of flare (hazard ratio (HR) 8.75 (4.02-19.06) 95% confidence interval (CI)). Hospitalization, surgery, switch of treatment, initiation and escalation of anti-tumor necrosis factor (TNF) therapy, steroids initiation, and increased fecal calprotectin levels at 6 months were associated with bactDNA at baseline. A logistic regression analysis showed bactDNA as an independent and significant predictive factor of hospitalization (odds ratio (OR) 11.9 (3.4-42.3); P<0.001), steroids startup (OR 8.5 (2.7-27.1); P<0.001), and switch of treatment (OR 3.5 (1.6-7.7); P=0.002) at 6 months. No relationship was observed between bactDNA and mucosal lesions in patients with colonoscopy at admission. Serum pro-inflammatory cytokines were significantly increased in patients with bactDNA or a variant-NOD2 genotype. The combination of both factors induced decreased anti-TNF-α levels and a higher percentage of patients on intensified anti-TNF therapy.

CONCLUSIONS

BactDNA is an independent risk factor of relapse at 6 months in CD patients. BactDNA is also independently associated with an increased risk of hospitalization, switch of treatment, and steroids initiation.

Induction of regulatory T cells: A role for probiotics and prebiotics to suppress autoimmunity

Regulatory T cells (Tregs) are comprised of a heterogeneous population of cells that play a vital role in suppressing inflammation and maintaining immune tolerance. Given the crucial role of Tregs in maintaining immune homeostasis, it is probably not surprising that many microbial species and their metabolites have the potential to induce Tregs. There is now great interest in the therapeutic potential of probiotics and prebiotics based strategies for a range of autoimmune disorders. This review will summarise recent findings concerning the role of probiotics and prebiotics in induction of Tregs to ameliorate the autoimmune conditions. In addition, the article is focused to explain the different mechanisms of Treg induction and function by these probiotics and prebiotics, based on the available studies till date. The article further proposes that induction of Tregs by probiotics and prebiotics could lead to the development of new therapeutic approach towards curbing the autoimmune response and as an alternative to detrimental immunosuppressive drugs.

Nutritional Support of Patient with Inflammatory Bowel Disease

Ideally, surgical patients should be nutritionally optimized, as better nutritional status correlates with favorable outcomes during the perioperative period. As inflammatory bowel disease often leads to overall malnutrition, special consideration should be given to this patient population by surgeons. In this article, we review methods for nutritional assessment and provide nutritional recommendations for this special surgical population.

Estrogen receptor beta as target for colorectal cancer prevention

Colorectal cancer (CRC) is a leading cause of death in the United States. Despite its slow development and the capacity for early diagnosis, current preventive approaches are not sufficient. However, a role for estrogen has been demonstrated in multiple epidemiologic studies, which may benefit CRC prevention. A large body of evidence from preclinical studies indicates that expression of the estrogen receptor beta (ERβ/ESR2) demonstrates an inverse relationship with the presence of colorectal polyps and stage of tumors, and can mediate a protective response. Natural compounds, including phytoestrogens, or synthetic ERβ selective agonists, can activate or upregulate ERβ in the colon and promote apoptosis in preclinical models and in clinical experience. Importantly, this activity has been associated with a reduction in polyp formation and, in rodent models of CRC, has been shown to lower incidence of colon adenocarcinoma. Collectively, these findings indicate that targeted activation of ERβ may represent a novel clinical approach for management of colorectal adenomatous polyps and prevention of colorectal carcinoma in patients at risk for this condition. In this review, we discuss the potential of new chemopreventive or dietary approaches based on estrogen signaling.

Pathological and therapeutic interactions between bacteriophages, microbes and the host in inflammatory bowel disease

The intestinal microbiome is a dynamic system of interactions between the host and its microbes. Under physiological conditions, a fine balance and mutually beneficial relationship is present. Disruption of this balance is a hallmark of inflammatory bowel disease (IBD). Whether an altered microbiome is the consequence or the cause of IBD is currently not fully understood. The pathogenesis of IBD is believed to be a complex interaction between genetic predisposition, the immune system and environmental factors. In the recent years, metagenomic studies of the human microbiome have provided useful data that are helping to assemble the IBD puzzle. In this review, we summarize and discuss current knowledge on the composition of the intestinal microbiota in IBD, host-microbe interactions and therapeutic possibilities using bacteria in IBD. Moreover, an outlook on the possible contribution of bacteriophages in the pathogenesis and therapy of IBD is provided.

Antioxidant therapy for treatment of inflammatory bowel disease: Does it work?

Oxidative stress (OS) is considered as one of the etiologic factors involved in several signals and symptoms of inflammatory bowel diseases (IBD) that include diarrhea, toxic megacolon and abdominal pain. This systematic review discusses approaches, challenges and perspectives into the use of nontraditional antioxidant therapy on IBD, including natural and synthetic compounds in both human and animal models. One hundred and thirty four papers were identified, of which only four were evaluated in humans. Some of the challenges identified in this review can shed light on this fact: lack of standardization of OS biomarkers, absence of safety data and clinical trials for the chemicals and biological molecules, as well as the fact that most of the compounds were not repeatedly tested in several situations, including acute and chronic colitis. This review hopes to stimulate researchers to become more involved in this fruitful area, to warrant investigation of novel, alternative and efficacious antioxidant-based therapies.

•

Major biomarkers used for evaluation of antioxidant therapy were MPO, TBARS/MDA and glutathione levels.

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Challenges were identified for the yet poor use of antioxidant therapy in IBD.

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This review stimulates the investigation of alternative and efficacious antioxidant therapies.

Intestinal microbial metabolism of phosphatidylcholine: a novel insight in the cardiovascular risk scenario

Intestinal microbiota is a "dynamic organ" influencing host metabolism, nutrition, physiology and immune system. Among its several interactions, the role of a phosphatidylcholine metabolite derived by gut flora activity, i.e., trimethylamine-N-oxide (TMAO), allows perceiving a novel insight in the cardiovascular risk scenario, being a strong predictor of this condition. Based on current reports, including the paper of Tang et al., we describe here: the possible role of intestinal microbiota in cardiovascular risk as well as potential interventions to reduce gut flora TMAO production by diet, probiotics and antibiotics. Finally, we highlight the possibility of evaluating, monitoring and modulating TMAO in order to use its serum levels as a marker of cardiovascular risk in the next future, when the need of controlled studies on large series will be satisfied.

Breakthrough Lactobacillus rhamnosus GG bacteremia associated with probiotic use in an adult patient with severe active ulcerative colitis: case report and review of the literature

BACKGROUND

Probiotics are widely investigated in the treatment of various bowel diseases. However, they may also have a pathogenic potential, and the role of Lactobacillus spp. as opportunistic pathogens, mostly following disruption of the intestinal mucosa, is emerging.

CASE REPORT

We report on a case of bacteremia caused by L. rhamnosus GG in an adult patient affected by severe active ulcerative colitis under treatment with corticosteroids and mesalazine. Lactobacillus bacteremia was associated with candidemia and occurred while the patient was receiving a probiotic formulation containing the same strain (as determined by PFGE typing), and was being concomitantly treated with i.v. vancomycin, to which the Lactobacillus strain was resistant. L. rhamnosus GG bacteremia, therefore, was apparently related with translocation of bacteria from the intestinal lumen to the blood.

CONCLUSIONS

Pending conclusive evidence, use of probiotics should be considered with caution in case of active severe inflammatory bowel diseases with mucosal disruption.

Serum Levels of Lipopolysaccharide and 1,3-β-D-Glucan Refer to the Severity in Patients with Crohn's Disease

Objectives. Interactions between the host and gut microbial community contribute to the pathogenesis of Crohn's disease (CD). In this study, we aimed to detect lipopolysaccharide (LPS) and 1,3-β-D-glucan (BG) in the sera of CD patients and clarify the potential role in the diagnosis and therapeutic approaches. Materials and Methods. Serum samples were collected from 46 patients with active CD (A-CD), 22 CD patients at remission stage (R-CD), and 20 healthy controls, and the levels of LPS, BG, and TNF in sera were determined by ELISA. Moreover, sixteen patients with A-CD received anti-TNF monoclonal antibody therapy (infliximab, IFX) at a dose of 5 mg/kg body weight at weeks 0, 2, and 6, and the levels of LPS and BG were also tested at week 12 after the first intravenous infusion. Results. Serum levels of LPS and BG were found to be markedly increased in A-CD patients compared with R-CD patients and healthy controls (P < 0.05). They were also observed to be positively correlated with CDAI, ESR, and SES-CD, respectively (P < 0.05). Furthermore, the levels of TNF in sera had a significant correlation with LPS and BG, respectively. The concentrations of LPS and BG were demonstrated to be significantly downregulated in the sera of A-CD patients 12 weeks after IFX treatment (P < 0.05), suggesting that blockade of TNF could inhibit bacterial endotoxin absorption, partially through improving intestinal mucosal barrier. Conclusions. Serum levels of LPS and BG are significantly increased in A-CD patients and positively correlated with the severity of the disease. Blockade of intestinal mucosal inflammation with IFX could reduce the levels of LPS and BG in sera. Therefore, this study has shed some light on measurement of serum LPS and BG in the diagnosis and treatment of CD patients.

Products for the treatment of inflammatory bowel disease: a patent review (2013 - 2014)

INTRODUCTION

Inflammatory bowel disease (IBD) consists of Crohn's disease, ulcerative colitis and an unspecific IBD. The unclear etiology of IBD is a limiting factor that complicates the development of new pharmacological treatments and explains the high frequency of refractory patients to current drugs, including both conventional and biological therapies. In view of this, recent progress on the development of novel patented products to treat IBD was reviewed.

AREAS COVERED

Evaluation of the patent literature during the period 2013 - 2014 focused on chemical compounds, functional foods and biological therapy useful for the treatment of IBD.

EXPERT OPINION

Majority of the patents are not conclusive because they were based on data from unspecific methods not related to intestinal inflammation and, when related to IBD models, few biochemical and molecular evaluations that could be corroborating their use in human IBD were presented. On the other hand, methods and strategies using new formulations of conventional drugs, guanylyl cyclase C peptide agonists, compounds that influence anti-adhesion molecules, mAbs anti-type I interferons and anti-integrin, oligonucleotide antisense Smad7, growth factor neuregulin 4 and functional foods, particularly fermented wheat germ with Saccharomyces cerevisiae, are promising products for use in the very near future.

Maintaining gut ecosystems for health: Are transitory food bugs stowaways or part of the crew?

Do food ecosystems feed gut ecosystems? And if so… fuel the immune system? Recent developments in metagenomics have provided researchers tools to open the "black box" of microbiome science. These novel technologies have enabled the establishment of correlations between dysbiotic microbial communities and many diseases. The complex interaction of the commensal microbiota with the immune system is a topic of substantial interest due to its relevance to health. The human gastrointestinal tract is composed of an immense number of resident and transient microorganisms. Both may play a direct and vital role in the maintenance of human health and well-being. An understanding of the interactions and mechanisms through which commensal and food-derived microbes shape host immunity and metabolism may yield new insights into the pathogenesis of many immune-mediated diseases. Consequently, by manipulating the contribution of food microbiota to the functionality of the gut ecosystem, there is great hope for development of new prophylactic and therapeutic interventions. This paper presents some insights and comments on the possible impact of exogenous fermented food microbes on the gut homeostasis. We shed light on the similar features shared by both fermented food microbes and probiotics. In particular, the key role of microbial strains as part of food ecosystems for health and diseases is discussed through the prism of fermented dairy products and gut inflammation.