The bacterial flora in inflammatory bowel disease: current insights in pathogenesis and the influence of antibiotics and probiotics

Increased Risk of Inflammatory Bowel Disease Among Patients With Nontyphoidal Salmonella Infections: A Population-Based Cohort Study

BACKGROUND

Despite the known association between microorganisms and development of inflammatory bowel disease (IBD), the role of nontyphoidal Salmonella (NTS) in IBD is not adequately addressed. We aimed at elucidating the relationship between NTS infection and the risk of IBD.

METHODS

Based on the National Health Insurance Research Database in Taiwan, this retrospective cohort study enrolled patients with NTS infection (exposure group; n = 4651) and those without NTS infection (comparator group; n = 4651) who were propensity score matched (1:1) by demographic data, medications, comorbidities, and index date. All patients were followed until IBD onset, individual mortality, or December 31, 2018. Cox proportional hazards regression analysis was performed to determine the hazard ratios and 95% confidence intervals (CIs). Sensitivity analyses were used for cross-validation.

RESULTS

The NTS group demonstrated an increased risk of IBD compared with the non-NTS groups (adjusted hazard ratio [aHR], 2.12; 95% CI, 1.62-2.78) with a higher risk of developing ulcerative colitis in the former (aHR, 2.27; 95% CI, 1.69-3.04). Nevertheless, the small sample size may contribute to lack of significant difference in Crohn's disease. Consistent findings were noted after excluding IBD diagnosed within 6 months of NTS infection (aHR, 2.28; 95% CI, 1.71-3.03), excluding those with enteritis/colitis before index date (aHR, 1.85; 95% CI, 1.28-2.68), excluding those using antibiotics for 1 month in the year before IBD onset (aHR, 1.81; 95% CI, 1.34-2.45), inverse probability of treatment weighting (aHR, 1.64; 95% CI, 1.31-2.04), and inclusion of individuals regardless of age (n = 10 431; aHR, 1.83; 95% CI, 1.53-2.19).

CONCLUSIONS

Patients with NTS were associated with an increased risk of developing IBD, especially ulcerative colitis.

Mucin glycans and their degradation by gut microbiota

The human intestinal tract is inhabited by a tremendous number of microorganisms, which are collectively termed "the gut microbiota". The intestinal epithelium is covered with a dense layer of mucus that prevents penetration of the gut microbiota into underlying tissues of the host. Recent studies have shown that the maturation and function of the mucus layer are strongly influenced by the gut microbiota, and alteration in the structure and function of the gut microbiota is implicated in several diseases. Because the intestinal mucus layer is at a crucial interface between microbes and their host, its breakdown leads to gut bacterial invasion that can eventually cause inflammation and infection. The mucus is composed of mucin, which is rich in glycans, and the various structures of the complex carbohydrates of mucins can select for distinct mucosa-associated bacteria that are able to bind mucin glycans, and sometimes degrade them as a nutrient source. Mucin glycans are diverse molecules, and thus mucin glycan degradation is a complex process that requires a broad range of glycan-degrading enzymes. Because of the increased recognition of the role of mucus-associated microbes in human health, how commensal bacteria degrade and use host mucin glycans has become of increased interest. This review provides an overview of the relationships between the mucin glycan of the host and gut commensal bacteria, with a focus on mucin degradation.

Advances and future perspectives in epithelial drug delivery

Epithelial surfaces protect exposed tissues in the body against intrusion of foreign materials, including xenobiotics, pollen and microbiota. The relative permeability of the various epithelia reflects their extent of exposure to the external environment and is in the ranking: intestinal≈ nasal ≥ bronchial ≥ tracheal > vaginal ≥ rectal > blood-perilymph barrier (otic), corneal > buccal > skin. Each epithelium also varies in their morphology, biochemistry, physiology, immunology and external fluid in line with their function. Each epithelium is also used as drug delivery sites to treat local conditions and, in some cases, for systemic delivery. The associated delivery systems have had to evolve to enable the delivery of larger drugs and biologicals, such as peptides, proteins, antibodies and biologicals and now include a range of physical, chemical, electrical, light, sound and other enhancement technologies. In addition, the quality-by-design approach to product regulation and the growth of generic products have also fostered advancement in epithelial drug delivery systems.

Bile Acids and the Microbiome: Making Sense of This Dynamic Relationship in Their Role and Management in Crohn's Disease

BACKGROUND

Bile acids help maintain the physiological balance of the gut microbiome and the integrity of the intestinal epithelial barrier. Similarly, intestinal bacteria play a major role in bile acid metabolism as they are involved in crucial biotransformation steps in the enterohepatic circulation pathway. Understanding the relationship between bile acid signalling and the gut microbiome in Crohn's disease can help target new and innovative treatment strategies.

AIMS

This review summarises the relationship between bile acids and the microbiome in Crohn's disease and discusses potential novel therapeutic options.

METHODS

We performed a literature review on bile acid signalling, its effect on the gut microbiome, and therapeutic applications in Crohn's disease.

RESULTS

Current research suggests that there is a strong interplay between the dysregulated microbiota, bile acid metabolism, and the mucosal immune system that can result in a changed immunological function, triggering the inflammatory response in Crohn's disease. Recent studies have demonstrated an association with altering the enterohepatic circulation and activating the farnesoid X receptor signalling pathway with the use of probiotics and faecal microbial transplantation, respectively. Bile acid sequestrants have been shown to have anti-inflammatory, cytoprotective, and anti-apoptotic properties with the potential to alter the intestinal microbial composition, suggesting a possible role in inducing and maintaining Crohn's disease.

CONCLUSIONS

Active Crohn's disease has been correlated with changes in bacterial concentrations, which may be associated with changes in bile acid modification. Further research should focus on targeting these areas for future therapeutic options.

USE OF METABOLOMICS TO THE DIAGNOSIS OF INFLAMMATORY BOWEL DISEASE

BACKGROUND

Crohn's disease and ulcerative colitis are the primary inflammatory bowel diseases (IBD), and its pathogenesis is related to genetic and environmental factors. Currently, the diagnosis of IBD results in a multidisciplinary approach with significant disadvantages, such as its invasive nature, time spent, and the fact that 10% of patients remain without diagnostic classification. However, new methodologies of analysis have emerged that allowed the expansion of knowledge about IBD, as the metabolomics, the study of metabolites. The presence and prevalence of such metabolites may prove to be useful as biomarkers in the diagnosis of IBD.

OBJECTIVE

Analyze fecal samples for metabolic analysis in the diagnosis of inflammatory bowel diseases (IBD), providing differentiation between Crohn's disease and ulcerative colitis.

METHODS

This is an observational study with 21 patients diagnosed with IBD (ulcerative colitis 11 and Crohn's disease 10) and 15 healthy controls, all with the consent and clarification. The fecal extracts of all patients are submitted to a high-resolution Nuclear Magnetic Resonance Hydrogen (1H-NMR) spectroscopy combined with multivariate and univariate pattern recognition techniques. Through the metabolomics of fecal extracts, gives us a characterization of employing a noninvasive approach.

RESULTS

We identify some metabolites, such as lactate, succinate, alanine, and tyrosine, in the Crohn's disease fecal samples, and leucine, alanine, and tyrosine in the ulcerative colitis fecal samples. All the amino acids presented positive covariance for disease correlation.

CONCLUSION

The results showed different metabolic profiles between IBD patients and healthy volunteers based on 1H-NMR analysis of fecal extracts. Moreover, the approach discriminated patients with Crohn's disease and ulcerative colitis. The metabolomics analysis is promising as a novel diagnostic technique for further IBD recognition and surveillance. New studies are necessary to validate these findings.

Advances in Oral Drug Delivery for Regional Targeting in the Gastrointestinal Tract - Influence of Physiological, Pathophysiological and Pharmaceutical Factors

The oral route is by far the most common route of drug administration in the gastrointestinal tract and can be used for both systemic drug delivery and for treating local gastrointestinal diseases. It is the most preferred route by patients, due to its advantages, such as ease of use, non-invasiveness, and convenience for self-administration. Formulations can also be designed to enhance drug delivery to specific regions in the upper or lower gastrointestinal tract. Despite the clear advantages offered by the oral route, drug delivery can be challenging as the human gastrointestinal tract is complex and displays a number of physiological barriers that affect drug delivery. Among these challenges are poor drug stability, poor drug solubility, and low drug permeability across the mucosal barriers. Attempts to overcome these issues have focused on improved understanding of the physiology of the gastrointestinal tract in both healthy and diseased states. Innovative pharmaceutical approaches have also been explored to improve regional drug targeting in the gastrointestinal tract, including nanoparticulate formulations. This review will discuss the physiological, pathophysiological, and pharmaceutical considerations influencing drug delivery for the oral route of administration, as well as the conventional and novel drug delivery approaches. The translational challenges and development aspects of novel formulations will also be addressed.

Microbial dysbiosis in inflammatory bowel diseases: results of a metagenomic study in Saudi Arabia

BACKGROUND

The intestinal microbiota plays an essential role in the pathogenesis of ulcerative colitis (UC)and Crohn disease (CD).

METHODS

Metagenomic studies were used to study microbiota in the diagnosed cases of UC and CD at King Fahad Medical City, Riyadh, Saudi Arabia. Each segment of the colon was flushed with distilled water during colonoscopy, and the material was aspirated, immediately frozen for the study. The patients attending for screening colonoscopies were taken as age-matched healthy controls. The UC patients were followed clinically for any signs of exacerbation relapse, and CD patients were followed for any complications.

RESULTS

The metagenomic data on 46 (24 females) patients with CD were analyzed along with a group of age and gender-matched controls. Their age ranged from 14 to 65 years, mean age 25.19±10.67 years. There were 50 UC patient (28 females) mean age of 34.42±12.58, and their age ranged from 13-58 years. This study identified enrichment of 19 genera in the control group (Abiotrophia, Anaerofustis, Butyrivibrio, Campylobacter, Catenibacterium, Coprococcus, Dorea, Eubacterium, Facklamia, Klebsiella, Lactococcus, Oscillibacter, Paenibacillus, Parabacteroides, Parasutterella, Porphyromonas, Prevotella, Ruminococcus, Treponema). There was a significant enrichment of 14 genera in our CD cohort (Beggiatoa, Burkholderia, Cyanothece, Enterococcus, Escherichia, Fusobacterium, Jonquetella, Mitsuokella, Parvimonas, Peptostreptococcus, Shigella, Succinatimonas, ThermoanaerobacterVerrucomicrobiales, Vibrio). There was a significant enrichment of 7 genera in UC cohort (Beggiatoa, Burkholderia, Parascardovia, Parvimonas, Pseudoflavonifractor, Thermoanaerobacter, Verrucomicrobiales).

CONCLUSIONS

A significant dysbiosis was found in UC and CD patients compared to controls.

Edwardsiella tarda Infection Triggering Acute Relapse in Pediatric Crohn's Disease

Crohn's disease exacerbations can often be associated with bacterial infections causing gastroenteritis. We report a child who experienced exacerbation of his Crohn's disease associated with a positive stool culture for Edwardsiella tarda (E. tarda). Endoscopy showed features of moderate inflammation similar to exacerbation of Crohn's disease. The patient was treated simultaneously with intravenous steroids and antibiotics, and his symptoms resolved. This case report highlights the importance of clinicians being able to promptly recognize and treat concurrent bacterial infections in Crohn's disease exacerbations.

Evaluation of a microbial muramidase supplementation on growth performance, apparent ileal digestibility, and intestinal histology of broiler chickens

The current study evaluated the effects of different inclusion levels of microbial muramidase (Muramidase 007, DSM Nutritional Products) on gastrointestinal functionality by determination of apparent ileal digestibility (AID) of nutrients, investigation of intestinal histomorphology, and quantification of resulting growth performance. Four maize-wheat-soybean experimental diets were produced without (C) and with different dosages of muramidase: low (L, 25,000 LSU(F)/kg), medium (M, 35,000 LSU(F)/kg), and high (H, 45,000 LSU(F)/kg); diets were fed to broilers for 35 d. At the end of the experiment, AID of ether extract (EE), crude protein (CP), Ca, and P were determined and samples of the mid-jejunum and -ileum were collected for histomorphological observations. Data were subjected to ANOVA analysis using the GLM procedure. Orthogonal polynomial contrasts were used to assess linear and quadratic effects of different levels of the muramidase. At the end of the trial, Muramidase 007 supplementation linearly increased body weight gain and decreased feed conversion ratio (FCR) (P ≤ 0.05). Adding the muramidase to broiler diets also linearly increased the European poultry efficiency factor (P ≤ 0.05). Inclusion of the muramidase in broiler diets linearly increased AID of CP, EE, and P (P ≤ 0.05), and the H group had a higher AID of EE and CP compared to C group (P ≤ 0.05). Microbial muramidase supplementation linearly increased ileal villus length to crypt depth ratio and decreased the number of ileal CD45 cells (P ≤ 0.05). Broilers fed M and H diets had fewer number of CD45 cells in the ileum compared to those in C group (P ≤ 0.05). In conclusion, the results of the present study demonstrated that inclusion of the microbial muramidase in broiler diets could increase AID of key nutrients and improve growth performance in broilers. Adding microbial muramidase to broiler diets can therefore be considered as an interesting prospect to improve gastrointestinal functionality. Biological mechanisms causing these improvements need to be studied further.

Review of the effects of silver nanoparticle exposure on gut bacteria

Gut bacteria are involved in regulating several important physiological functions in the host, and intestinal dysbacteriosis plays an important role in several human diseases, including intestinal, metabolic and autoimmune disorders. Although silver nanoparticles (AgNPs) are increasingly being incorporated into medical and consumer products due to their unique physicochemical properties, studies have indicated their potential to affect adversely the gut bacteria. In this review, we focus on the biotoxicological effects of AgNPs entering the gastrointestinal tract and the relationship of these effects with important nanoscale properties. We discuss in detail the mechanisms underlying the bactericidal toxicity effects of AgNPs and explore the relationships between AgNPs, gut bacteria and disease. Finally, we highlight the need to focus on the negative effects of AgNPs usage to facilitate appropriate development of these particles.

Potential Synergies of β-Hydroxybutyrate and Butyrate on the Modulation of Metabolism, Inflammation, Cognition, and General Health

The low-carbohydrate high-fat diet (LCHFD), also known as the ketogenic diet, has cycled in and out of popularity for decades as a therapeutic program to treat metabolic syndrome, weight mismanagement, and drug-resistant disorders as complex as epilepsy, cancer, dementia, and depression. Despite the benefits of this diet, health care professionals still question its safety due to the elevated serum ketones it induces and the limited dietary fiber. To compound the controversy, patient compliance with the program is poor due to the restrictive nature of the diet and symptoms related to energy deficit and gastrointestinal adversity during the introductory and energy substrate transition phase of the diet. The studies presented here demonstrate safety and efficacy of the diet including the scientific support and rationale for the administration of exogenous ketone bodies and ketone sources as a complement to the restrictive dietary protocol or as an alternative to the diet. This review also highlights the synergy provided by exogenous ketone, β-hydroxybutyrate (BHB), accompanied by the short chain fatty acid, butyrate (BA) in the context of cellular and physiological outcomes. More work is needed to unveil the molecular mechanisms by which this program provides health benefits.

Effect of Yoghurt on the Cytokine Profile using a Murine Model of Intestinal Inflammation

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, are important problems in industrialized countries. The complete aetiology of both diseases is still unknown but likely involves genetic, environmental and immunological factors. The aim of this work is to study the anti-inflammatory mechanisms reported for yoghurt in a colon cancer model in order to evaluate its usefulness in the treatment of intestinal inflammation such as Crohn's disease. A trinitrobenzenesulfonic acid (TNBS)-induced colitis model was used. The influence of yoghurt feeding was studied before and after TNBS inoculation. The effect on the intestinal microbiota and on the host immune response was evaluated. IgA-producing cells and cells positive for specific cytokines (IL-12, IL-17, IFNγ and IL-10) were analyzed. Yoghurt administration diminished the severity of inflammation in the TNBS-inoculated mice. This effect occurred mainly through IL-10, which was increased in the intestinal tissues throughout the study, and by the decrease observed in IL-17 and IL-12 levels. In addition to this immunomodulatory capacity, another mechanism by which yoghurt could exert the anti-inflammatory activity observed in our model would be through beneficial changes in the intestinal microbiota (increases in the bifidobacteria and lactobacilli populations). These changes in the intestinal microbiota could also be considered one of the causes of the intestinal inflammation reduction. These results show that yoghurt administration modulated the immune response, inducing down regulation of the inflammatory cytokines produced by the immune cells involved in the inflammatory process. The protective effect

Personalizing protein nourishment

Proteins are not equally digestible-their proteolytic susceptibility varies by their source and processing method. Incomplete digestion increases colonic microbial protein fermentation (putrefaction), which produces toxic metabolites that can induce inflammation in vitro and have been associated with inflammation in vivo. Individual humans differ in protein digestive capacity based on phenotypes, particularly disease states. To avoid putrefaction-induced intestinal inflammation, protein sources, and processing methods must be tailored to the consumer's digestive capacity. This review explores how food processing techniques alter protein digestibility and examines how physiological conditions alter digestive capacity. Possible solutions to improving digestive function or matching low digestive capacity with more digestible protein sources are explored. Beyond the ileal digestibility measurements of protein digestibility, less invasive, quicker and cheaper techniques for monitoring the extent of protein digestion and fermentation are needed to personalize protein nourishment. Biomarkers of protein digestive capacity and efficiency can be identified with the toolsets of peptidomics, metabolomics, microbial sequencing and multiplexed protein analysis of fecal and urine samples. By monitoring individual protein digestive function, the protein component of diets can be tailored via protein source and processing selection to match individual needs to minimize colonic putrefaction and, thus, optimize gut health.

Effects of Natural and Chemically Defined Nutrients on Candida albicans Water-soluble Fraction (CAWS) Vasculitis in Mice

Kawasaki disease (KD) is an inflammatory disease that was identified by Professor Tomisaku Kawasaki in 1961. Candida albicans-derived substances, such as C. albicans water-soluble fraction (CAWS) , induce coronary arteritis similar to KD in mice. CAWS functions as a pathogen-associated molecular pattern (PAMP) by acting as a ligand for dectin-2. A gut-associated immunological system has developed specifically to segregate advantageous and detrimental stimuli, and the microbial flora has been found to markedly affect the development and severity of diseases. We herein investigated whether diet affects the onset and progression of CAWS vasculitis in mice. A standard diet, CE-2, and chemically defined diet, AIN93G, which is free of β-glucan, were used. Although all mice administered with CAWS died, the mean number of survival days was smaller in the AIN93G group because vasculitis was induced earlier than in the CE-2 group. Bacteroides, which are inflammatory flora, were enriched in the microbial flora of the AIN93G group. The results of the present study suggest that diet quality affects not only microbial flora changes, but also the progression of systemic disease.

Bifidobacterium longum affects the methylation level of forkhead box P3 promoter in 2, 4, 6-trinitrobenzenesulphonic acid induced colitis in rats

Bifidobacterium longum (B. Longum) is a common probiotic colonized in the human gut and against the development of chronic inflammation including inflammatory bowel disease (IBD). But the underlying mechanism remains unknown. The aim of this study was to evaluate the affection of B. longum on the methylation levels of forkhead box P3 (Foxp3) promoter. 2, 4, 6-trinitrobenzenesulphonic acid (TNBS)-induced colitis rat models were treated with B. longum or medium, respectively. The genomic DNA of spleen peripheral blood mononuclear cells (PBMC) cells was extracted. After bisulphite treatment and pyrosequencing, the methylation levels of each CpG sites in the promoter of forkhead box protein P3 (Foxp3) were analyzed. B. Longum treatment changes the methylation level in Foxp3 promoter in TNBS-treated colitis rats, and significantly demethylates several CpG sites in Foxp3 promoter. The demethylation of Foxp3 promoter might be involved in the effectiveness of B. Longum treatment for IBD. Further research remains necessary to investigate the role of B. Longum in Foxp3 demethylation. Using B. Longum or its metabolic products is an option for further investigations on potential treatments for IBD.

Inflammatory arthritis complicated by inflammatory bowel disease: two case reports

Coexistence of inflammatory arthritis disease and inflammatory bowel disease (IBD) is often considered to be relatively rare, and the underlying mechanisms of the association between them remain unclear. Herein, we report two cases of IBD which occurred during the course of inflammatory arthritis disease. The first case had psoriatic arthritis (PsA) for two and a half years complicated by Crohn's disease and accompanied by inactive carrier state of hepatitis B. The second case had rheumatoid arthritis (RA) complicated by ulcerative colitis four years after the onset of RA. In both cases, colonoscopy was performed, and their clinical presentations improved with a multidisciplinary approach. In the event of complaints related to the gastrointestinal tract in patients with PsA or RA, IBD should be kept in mind, and the clinical evaluation and multidisciplinary interventions should be planned to control the underlying autoimmune process.

Anaerobes as Sources of Bioactive Compounds and Health Promoting Tools

Aerobic microorganisms have been sources of medicinal agents for several decades and an impressive variety of drugs have been isolated from their cultures, studied and formulated to treat or prevent diseases. On the other hand, anaerobes, which are believed to be the oldest life forms on earth and evolved remarkably diverse physiological functions, have largely been neglected as sources of bioactive compounds. However, results obtained from the limited research done so far show that anaerobes are capable of producing a range of interesting bioactive compounds that can promote human health. In fact, some of these bioactive compounds are found to be novel in their structure and/or mode of action.Anaerobes play health-promoting roles through their bioactive products as well as application of whole cells. The bioactive compounds produced by these microorganisms include antimicrobial agents and substances such as immunomodulators and vitamins. Bacteriocins produced by anaerobes have been in use as preservatives for about 40 years. Because these substances are effective at low concentrations, encounter relatively less resistance from bacteria and are safe to use, there is a growing interest in these antimicrobial agents. Moreover, several antibiotics have been reported from the cultures of anaerobes. Closthioamide and andrimid produced by Clostridium cellulolyticum and Pantoea agglomerans, respectively, are examples of novel antibiotics of anaerobe origin. The discovery of such novel bioactive compounds is expected to encourage further studies which can potentially lead to tapping of the antibiotic production potential of this fascinating group of microorganisms.Anaerobes are widely used in preparation of fermented foods and beverages. During the fermentation processes, these organisms produce a number of bioactive compounds including anticancer, antihypertensive and antioxidant substances. The well-known health promoting effect of fermented food is mostly due to these bioactive compounds. In addition to their products, whole cell anaerobes have very interesting applications for enhancing the quality of life. Probiotic anaerobes have been on the market for many years and are receiving growing acceptance as health promoters. Gut anaerobes have been used to treat patients suffering from severe Clostridium difficile infection syndromes including diarrhoea and colitis which cannot be treated by other means. Whole cell anaerobes are also studied to detect and cure cancer. In recent years, evidence is emerging that anaerobes constituting the microbiome are linked to our overall health. A dysfunctional microbiome is believed to be the cause of many diseases including cancer, allergy, infection, obesity, diabetes and several other disorders. Maintaining normal microflora is believed to alleviate some of these serious health problems. Indeed, the use of probiotics and prebiotics which favourably change the number and composition of the gut microflora is known to render a health promoting effect. Our interaction with the microbiome anaerobes is complex. In fact, not only our lives but also our identities are more closely linked to the anaerobic microbial world than we may possibly imagine. We are just at the beginning of unravelling the secret of association between the microbiome and human body, and a clear understanding of the association may bring a paradigm shift in the way we diagnose and treat diseases and disorders. This chapter highlights some of the work done on bioactive compounds and whole cell applications of the anaerobes that foster human health and improve the quality of life.

Risk of inflammatory bowel disease in patients with rosacea: Results from a nationwide cohort study in Taiwan

BACKGROUND

A link between rosacea and inflammatory bowel disease (IBD) has been proposed with unknown mechanisms. Epidemiologic evidence of this association needs to be examined.

METHODS

In this nationwide cohort study, a total of 89,356 patients with rosacea and 178,712 matched patients without rosacea between 1997 and 2013 were identified in the Taiwanese National Health Insurance Research Database. Cumulative incidences of IBD were compared between these 2 cohorts. Frailty Cox proportional hazard model was used and subgroup analyses were conducted to examine the risk factors for IBD.

RESULTS

The 15-year cumulative incidences of IBD were 0.036% (95% confidence interval [CI] 0.00%-1.57%) and 0.019% (95% CI 0.00%-0.83%) in rosacea and nonrosacea cohorts, respectively (P = .05). Rosacea (adjusted hazard ratio 1.94, 95% CI 1.04-3.63, P = .04) and male gender (adjusted hazard ratio 3.52, 95% CI 2.03-6.11, P < .01) were independently associated with IBD, after adjustment for major comorbidities. Multivariate subgroup analyses revealed consistent results. The incidence rates of IBD decreased with increasing antibiotic use in patients with rosacea, but without statistical significance.

LIMITATION

Information related to lifestyle, diet, alcohol, and smoking was not included in the database.

CONCLUSION

Patients with rosacea may have an increased risk of IBD.

Intestinal barrier dysfunction in human necrotizing enterocolitis

BACKGROUND

Intestinal barrier dysfunction has been implicated in necrotizing enterocolitis (NEC), but has not been directly measured in human NEC.

METHODS

Small intestines removed during surgery were immediately mounted in an Ussing chamber. mRNA expression of tight junction (TJ) proteins was measured with RT-PCR.

RESULTS

Fifteen infants were included, 5 with NEC and 10 with other diagnoses. Average transepithelial resistance (TER) was 11.61±1.65Ω/cm² in NEC specimens, 23.36±1.48Ω/cm² at resection margin, and 46.48±5.65Ω/cm² in controls. Average flux of permeability marker mannitol was 0.23±0.06μMol/cm² per h in NEC, 0.04±0.01 μMol/cm² per h at resection margin, and 0.017±0.004 μMol/cm² per h in control tissue (p<0.05). RT-PCR analysis showed marked decrease in mRNA expression of a TJ protein occludin in NEC affected tissue (p<0.03 vs. control). Additionally, mRNA expression of myosin light chain kinase (MLCK), an important regulator of TJ permeability, was increased in NEC specimens.

CONCLUSION

These studies show for the first time that NEC intestinal tissue have increased intestinal permeability, even at grossly healthy-appearing resection areas. The increase in intestinal permeability in NEC appeared to be related in part to a decrease in occludin and an increase in MLCK expression.

LEVEL OF EVIDENCE

Level 2.

Lower Level of Bacteroides in the Gut Microbiota Is Associated with Inflammatory Bowel Disease: A Meta-Analysis

Background and Aims. Multiple studies have reported associations between inflammatory bowel disease (IBD) and the flora disequilibrium of Bacteroides. We performed a meta-analysis of the available data to provide a more precise estimate of the association between Bacteroides level in the gut and IBD. Methods. We searched PubMed/MEDLINE, EMBASE, Cochrane Library, Wiley Library, BIOSIS previews, Web of Science, CNKI, and ScienceDirect databases for published literature on IBD and gut microbiota from 1990 to 2016. Quality of all eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). We compared the level of Bacteroides in IBD patients with that in a control group without IBD, different types of IBD patients, and IBD patients with active phase and in remission. Results. We identified 63 articles, 9 of which contained sufficient data for evaluation. The mean level of Bacteroides was significantly lower in Crohn's disease (CD) and ulcerative colitis (UC) patients in active phase than in normal controls. The level of Bacteroides in remission CD and UC patients was much lower than patients in the control group. Bacteroides level was even lower in patients with CD and UC in active phase than in remission. Conclusions. This analysis suggests that lower levels of Bacteroides are associated with IBD, especially in active phase.

Gut-lung axis: The microbial contributions and clinical implications

Gut microbiota interacts with host immune system in ways that influence the development of disease. Advances in respiratory immune system also broaden our knowledge of the interaction between host and microbiome in the lung. Increasing evidence indicated the intimate relationship between the gastrointestinal tract and respiratory tract. Exacerbations of chronic gut and lung disease have been shown to share key conceptual features with the disorder and dysregulation of the microbial ecosystem. In this review, we discuss the impact of gut and lung microbiota on disease exacerbation and progression, and the recent understanding of the immunological link between the gut and the lung, the gut-lung axis.

Fatal Clostridium perfringens Septicemia After Colonoscopic Polypectomy, Without Bowel Perforation

Since its introduction, colonoscopy has played an important role as a diagnostic, therapeutic, and screening tool. In general, colonoscopy is regarded as a safe procedure, but complications may occur. The most dreaded of these complications is colonic perforation. Bacteremia postprocedure may occur, and although it is not uncommon, it rarely results in clinically significant complications. Patients with IBD (inflammatory bowel disease) are a high-risk population for bacteremia, which may leads to bowel wall overstepping by the bacteria. With regard to that, we report a fatal case of gas gangrene complicating colonoscopy polypectomy without bowel perforation in a healthy adult. To the best of our knowledge, only two other cases of retroperitoneal gas gangrene associated with colonoscopy polypectomy without bowel perforation have been described in international literature, but none of which was completed by a molecular biology analysis.

Research Advance in Intestinal Mucosal Barrier and Pathogenesis of Crohn's Disease

To date, the etiology and pathogenesis of Crohn's disease (CD) have not been fully elucidated. It is widely accepted that genetic, immune, and environment factors are closely related to the development of CD. As an important defensive line for human body against the environment, intestinal mucosa is able to protect the homeostasis of gut bacteria and alleviate the intestinal inflammatory and immune response. It is evident that the dysfunction of intestinal mucosa barriers plays a crucial role in CD initiation and development. Yet researches are insufficient on intestinal mucosal barrier's action in the prevention of CD onset. This article summarizes the research advances about the correlations between the disorders of intestinal mucosal barriers and CD.

The immunology of the vermiform appendix: a review of the literature

This literature review assesses the current knowledge about the immunological aspects of the vermiform appendix in health and disease. An essential part of its immunological function is the interaction with the intestinal bacteria, a trait shown to be preserved during its evolution. The existence of the appendiceal biofilm in particular has proved to have a beneficial effect for the entire gut. In assessing the influence of acute appendicitis and the importance of a normally functioning gut flora, however, multiple immunological aspects point towards the appendix as a priming site for ulcerative colitis. Describing the immunological and microbiotical changes in the appendix during acute and chronic inflammation of the appendix, this review suggests that this association becomes increasingly plausible. Sustained by the distinct composition of cells, molecules and microbiota, as well as by the ever more likely negative correlation between the appendix and ulcerative colitis, the idea of the appendix being a vestigial organ should therefore be discarded.

PROBIOTIC APPROACHES FOR TARGETING INFLAMMATORY BOWEL DISEASE: AN UPDATE ON ADVANCES AND OPPORTUNITIES IN MANAGING THE DISEASE

Various commensal enteric and pathogenic bacteria may be involved in the pathogenesis of inflammatory bowel diseases (IBDs), a chronic condition with a pathogenic background that involves both immunogenetic and environmental factors. IBDs comprising of Crohn's disease, and ulcerative colitis, and pauchitis are chronic inflammatory conditions, and known for causing disturbed homeostatic balance among the intestinal immune compartment, gut epithelium and microbiome. An increasing trend of IBDs in incidence, prevalence, and severity has been reported during recent years. Probiotic strains have been reported to manage the IBDs and related pathologies, and hence are current hot topics of research for their potential to manage metabolic diseases as well as various immunopathologies. However, the probiotics industry will need to undergo a transformation, with increased focus on stringent manufacturing guidelines and high-quality clinical trials. This article reviews the present state of art of role of probiotic bacteria in reducing inflammation and strengthening the host immune system with reference to the management of IBDs. We infer that t healthcare will move beyond its prevailing focus on human physiology, and embrace the superorganism as a paradigm to understand and ameliorate IBDs.

A pseudo-kinetics approach for time-series metabolomics investigations: more reliable and sensitive biomarkers revealed in vincristine-induced paralytic ileus rats

A pseudo-kinetics approach was proposed to investigate global metabolic alterations and screen sensitive biomarkers based on AUC and T_max calculations.

Mechanisms and therapeutic effectiveness of lactobacilli

The gut microbiome is not a silent ecosystem but exerts several physiological and immunological functions. For many decades, lactobacilli have been used as an effective therapy for treatment of several pathological conditions displaying an overall positive safety profile. This review summarises the mechanisms and clinical evidence supporting therapeutic efficacy of lactobacilli. We searched Pubmed/Medline using the keyword ‘Lactobacillus’. Selected papers from 1950 to 2015 were chosen on the basis of their content. Relevant clinical and experimental articles using lactobacilli as therapeutic agents have been included. Applications of lactobacilli include kidney support for renal insufficiency, pancreas health, management of metabolic imbalance, and cancer treatment and prevention. In vitro and in vivo investigations have shown that prolonged lactobacilli administration induces qualitative and quantitative modifications in the human gastrointestinal microbial ecosystem with encouraging perspectives in counteracting pathology-associated physiological and immunological changes. Few studies have highlighted the risk of translocation with subsequent sepsis and bacteraemia following probiotic administration but there is still a lack of investigations on the dose effect of these compounds. Great care is thus required in the choice of the proper Lactobacillus species, their genetic stability and the translocation risk, mainly related to inflammatory disease-induced gut mucosa enhanced permeability. Finally, we need to determine the adequate amount of bacteria to be delivered in order to achieve the best clinical efficacy decreasing the risk of side effects.

Preventive and therapeutic effects of Lactobacillus paracasei B21060-based synbiotic treatment on gut inflammation and barrier integrity in colitic mice

BACKGROUND

Although gut microbiota perturbation is recognized as a main contributing factor to the pathogenesis of inflammatory bowel disease, synbiotic therapies, as prevention or treatment, have remained overlooked.

OBJECTIVE

To verify whether Lactobacillus paracasei B21060-based synbiotic therapy could prevent or repair colon damage in a mouse model of colitis, we performed treatments before and after colitis induction.

METHODS

The experimental study lasted 19 d. Experimental colitis was induced in BALB/c mice by giving them dextran sodium sulfate (DSS, 2.5%) in drinking water (days 7-12) followed by DSS-free water (days 13-19) (DSS group). L. paracasei B21060 (2.5 × 10(7) bacteria/10 g body weight) was orally administered 7 d before DSS [synbiotic as preventive treatment (P-SYN) group] or 2 d after DSS [synbiotic as therapeutic treatment (T-SYN) group] until day 19. Another group was not treated with DSS or synbiotic and was given tap water (control group), for a total of 4 groups.

RESULTS

Compared with the DSS group, both synbiotic-treated groups had significantly less pronounced weight loss and colon damage. Consistently, mRNA levels of chemokine (C-C motif) ligand 5 in the colon were reduced in both P-SYN and T-SYN mice compared with the DSS group (51%, P < 0.05 and 72%, P < 0.001, respectively). In the P-SYN and T-SYN groups, neutrophil elastase transcription was also reduced (51%, P < 0.01 and 59%, P < 0.001, respectively). Accordingly, oxidative/nitrosative stress was lower in P-SYN and T-SYN mice than in the DSS group. In P-SYN and T-SYN mice, colonic gene expression of tumor necrosis factor (47%, P < 0.01 and 61%, P < 0.001, respectively) and prostaglandin-endoperoxide synthase 2 (45%, P < 0.01 and 35%, P < 0.05, respectively) was lower, whereas interleukin 10 mRNA was doubled compared with the DSS group (both P < 0.5). Remarkably, epithelial barrier integrity (zonulin and occludin) and gut protection (β-defensin and mucin expression) were completely restored in P-SYN and T-SYN mice.

CONCLUSIONS

Our data highlight the beneficial effects of this synbiotic formulation in acutely colitic mice, suggesting that it may have therapeutic and possibly preventive efficacy in human colitis.

Different Dynamic Patterns of β-Lactams, Quinolones, Glycopeptides and Macrolides on Mouse Gut Microbial Diversity

The adverse impact of antibiotics on the gut microbiota has attracted extensive interest, particularly due to the development of microbiome research techniques in recent years. However, a direct comparison of the dynamic effects of various types of antibiotics using the same animal model has not been available. In the present study, we selected six antibiotics from four categories with the broadest clinical usage, namely, β-lactams (Ceftriaxone Sodium, Cefoperazone/Sulbactam and meropenem), quinolones (ofloxacin), glycopeptides (vancomycin), and macrolides (azithromycin), to treat BALB/c mice. Stool samples were collected during and after the administration of antibiotics, and microbial diversity was analyzed through Illumina sequencing and bioinformatics analyses using QIIME. Both α and β diversity analyses showed that ceftriaxone sodium, cefoperazone/sulbactam, meropenem and vancomycin changed the gut microbiota dramatically by the second day of antibiotic administration whereas the influence of ofloxacin was trivial. Azithromycin clearly changed the gut microbiota but much less than vancomycin and the β-lactams. In general, the community changes induced by the three β-lactam antibiotics showed consistency in inhibiting Papillibacter, Prevotella and Alistipes while inducing massive growth of Clostridium. The low diversity and high Clostridium level might be an important cause of Clostridium difficile infection after usage of β-lactams. Vancomycin was unique in that it inhibited Firmicutes, mainly the genus Clostridium. On the other hand, it induced the growth of Escherichia and effect lasted for months afterward. Azithromycin and meropenem induced the growth of Enterococcus. These findings will be useful for understanding the potential adverse effects of antibiotics on the gut microbiome and ensuring their better usage.

Environmental factors in the relapse and recurrence of inflammatory bowel disease: a review of the literature

INTRODUCTION

The causes of relapse in patients with Crohn's disease (CD) and ulcerative colitis (UC) are largely unknown. This paper reviews the epidemiological and clinical data on how medications (non-steroidal anti-inflammatory drugs, estrogens and antibiotics), lifestyle factors (smoking, psychological stress, diet and air pollution) may precipitate clinical relapses and recurrence. Potential biological mechanisms include: increasing thrombotic tendency, imbalances in prostaglandin synthesis, alterations in the composition of gut microbiota, and mucosal damage causing increased permeability.

RESULTS

The clinical epidemiological data consistently reports positive associations between smoking and relapses in CD, and inverse ones with UC. For NSAIDs and estrogens, the epidemiological findings are inconsistent, although general antibiotic use was associated with a reduced risk of relapse in CD. High levels of stress were positively associated with relapse, although psychological interventions did not have therapeutic benefits. The limited work on diet has reported sulphur-containing foods are positively associated with relapse in UC, but there is no work in CD. Ecological data reported positive correlations between air pollution levels and IBD hospitalisations.

CONCLUSIONS

In the future, to clarify this area, more clinical epidemiological work is required where detailed drug types and doses, and complete dietary intakes are measured, in specific forms of IBD. Such work could provide guidance to both patients and doctors to help maintain remission.

A prospective, randomized, blinded, placebo-controlled pilot study on the effect of Enterococcus faecium on clinical activity and intestinal gene expression in canine food-responsive chronic enteropathy

Background

Canine chronic enteropathies (CE) are believed to be caused by an aberrant immune response towards the intestinal microbiome. Administration of probiotics can alleviate colitis in people. In vitro effects of the probiotic Enterococcus faecium NCIMB 10415 E1707 (EF) previously have been evaluated using canine cells (e.g., whole blood, intestinal biopsies), but data on in vivo efficacy are lacking.

Hypothesis/Objectives

Administration of EF to dogs with food‐responsive CE will improve clinical outcome and decrease the intestinal inflammatory profile.

Animals

Dogs diagnosed with CE were prospectively recruited to receive a hydrolyzed elimination diet plus either a synbiotic product containing EF or placebo for 6 weeks. Both veterinary staff and owners were blinded to the treatment.

Methods

Clinical severity index (CCECAI), clinicopathological data and gene expression using intestinal biopsies (TLR2/4/5/9, IL‐17A, IL‐22, IL‐23p19, RORC, IL‐2, IL‐12p35, TNFα, IL‐4, IFNy, IL‐10, TGFβ, IL‐1β, IL‐18, NLRP3, casp‐1, TFF1, TFF3 and PPARy) before and after 6 weeks of treatment were analyzed using linear mixed modeling.

Results

Of the 45 cases recruited, 12 finished the clinical trial. Seven received the synbiotic and 5 the placebo product. There was no difference between groups or treatments regarding clinical efficacy, histology scores or expression of any of the investigated genes.

Conclusions and clinical importance

Standard dietary treatment induced rapid clinical response in all cases. Because the study was underpowered, it was not possible to determine whether or not EF had an additional effect within the time period of 6 weeks.

Advances in oral nano-delivery systems for colon targeted drug delivery in inflammatory bowel disease: selective targeting to diseased versus healthy tissue

Colon targeted drug delivery is an active area of research for local diseases affecting the colon, as it improves the efficacy of therapeutics and enables localized treatment, which reduces systemic toxicity. Targeted delivery of therapeutics to the colon is particularly advantageous for the treatment of inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease. Advances in oral drug delivery design have significantly improved the bioavailability of drugs to the colon; however in order for a drug to have therapeutic efficacy during disease, considerations must be made for the altered physiology of the gastrointestinal (GI) tract that is associated with GI inflammation. Nanotechnology has been used in oral dosage formulation design as strategies to further enhance uptake into diseased tissue within the colon. This review will describe some of the physiological challenges faced by orally administered delivery systems in IBD, the important developments in orally administered nano-delivery systems for colon targeting, and the future advances of this research.

FROM THE CLINICAL EDITOR

Inflammatory Bowel Disease (IBD) poses a significant problem for a large number of patients worldwide. Current medical therapy mostly aims at suppressing the active inflammatory episodes. In this review article, the authors described and discussed the various approaches current nano-delivery systems can offer in overcoming the limitations of conventional drug formulations.

A decrease of the butyrate-producing species Roseburia hominis and Faecalibacterium prausnitzii defines dysbiosis in patients with ulcerative colitis

OBJECTIVE

Bacteria play an important role in the onset and perpetuation of intestinal inflammation in inflammatory bowel disease (IBD). Unlike in Crohn's disease (CD), in which dysbiosis has been better characterised, in ulcerative colitis (UC), only small cohorts have been studied and showed conflicting data. Therefore, we evaluated in a large cohort if the microbial signature described in CD is also present in UC, and if we could characterise predominant dysbiosis in UC. To assess the functional impact of dysbiosis, we quantified the bacterial metabolites.

DESIGN

The predominant microbiota from 127 UC patients and 87 age and sex-matched controls was analysed using denaturing gradient gel electrophoresis (DGGE) analysis. Differences were quantitatively validated using real-time PCR. Metabolites were quantified using gas chromatography-mass spectrometry.

RESULTS

Based on DGGE analysis, the microbial signature previously described in CD was not present in UC. Real-time PCR analysis revealed a lower abundance of Roseburia hominis (p<0.0001) and Faecalibacterium prausnitzii (p<0.0001) in UC patients compared to controls. Both species showed an inverse correlation with disease activity. Short-chain fatty acids (SCFA) were reduced in UC patients (p=0.014), but no direct correlation between SCFA and the identified bacteria was found.

CONCLUSIONS

The composition of the fecal microbiota of UC patients differs from that of healthy individuals: we found a reduction in R hominis and F prausnitzii, both well-known butyrate-producing bacteria of the Firmicutes phylum. These results underscore the importance of dysbiosis in IBD but suggest that different bacterial species contribute to the pathogenesis of UC and CD.

In case of obesity, longevity-related mechanisms lead to anti-inflammation

The exact mechanisms which contribute to longevity have not been figured out yet. Our aim was to find out a common way for prompting longevity by bringing together the well-known applications such as food restriction, exercise, and probiotic supplementing in an experimental obesity model. Experimental obesity was promoted in a total of 32 young (2 months old) and 32 aged (16 months old) male Wistar albino rats through 8-week cafeteria diet (salami, chocolate, chips, and biscuits). Old and young animals were divided into groups each consisting of eight animals and also divided into four subgroups as obese control, obese food restriction, obese probiotic-fed and obese exercise groups. Probiotic group diet contained 0.05 %w/total diet inactive and lyophilized Lactobacillus casei str. Shirota. The exercise group was subjected to treadmill running 1 h/day, at 21 m/min and at an uphill incline of 15 % for 5 days a week. Food restriction group was formed by giving 40 % less food than the others. The control group was fed regular pellet feed ad libitum. This program was continued for 16 weeks. Blood samples from all the groups were analyzed for fasting glucose, insulin, IGF-1, insulin-like growth factor binding protein 3 (IGFBP-3), interleukin (IL)-6, IL-12, malondialdehyde (MDA), fT3, TT3, fT4, TT4, and liver tissue MDA levels were measured. All applications showed anti-inflammatory effects through the observed changes in the levels of IGFBP-3, IL-6, and IL-12 in the young and old obese rats. While the interventions normally contribute to longevity by recruiting different action mechanisms, anti-inflammatory effect is the only mode of action for all the applications in the obesity model.

Paediatric inflammatory bowel disease: a mechanistic approach to investigate exclusive enteral nutrition treatment

The inflammatory bowel diseases (IBD) include Crohn's disease (CD) and ulcerative colitis. The disease may present at any age although the peak of presentation is the second and third decades of life. The incidences of these diseases are increasing around the world with the age of presentation getting younger. At present CD is incurable with colectomy being the treatment for severe UC. Although several pharmacological approaches are used to modulate the inflammatory response in IBD, few lead to histological healing and most have side effects. An alternative approach is to use enteral formulae given exclusively (EEN) to treat IBD. EEN requires the consumption of an elemental or polymeric formula, with the exclusion of all other nutrients, for a period of up to 12 weeks. The introduction of EEN as a therapeutic option for IBD was through prudent observation; however, EEN has become an established and reliable option for the treatment of paediatric IBD. Despite this, the mechanisms through which EEN induces disease remission are unknown and remain hypothetical. This review will discuss recent research into EEN both describing clinical features of EEN therapy and discussing the most up-to-date understanding of the mechanisms through which EEN may be reducing intestinal inflammation and inducing disease remission.

Innate immunity and inflammatory bowel disease: a review of clinical evidence and future application

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder caused by dysregulated immune responses in a genetically predisposed individual. Recent accumulating data, including genome-wide association studies, have identified >100 distinct genetic loci that confer susceptibility. We highlight how the dysregulation of host-microbial interaction leads to intestinal inflammation, particularly with respect to the overlap of common genetic and pathophysiological mechanisms of IBD.

Osteoprotegerin exerts its pro-inflammatory effects through nuclear factor-κB activation

BACKGROUND

Osteoprotegerin (OPG), a soluble member of the tumor necrosis factor (TNF) receptor super-family, is a key factor inhibiting the differentiation and activation of osteoclasts. It has recently been implicated as a disease marker for inflammatory bowel disease (IBD) yet its role in the intestinal epithelial inflammatory response remains unknown.

AIM

The primary objective of this study was to investigate whether OPG has a role in intestinal inflammation and a potential role in IBD pathogenesis.

METHODS

Caco-2 and HT-29 cells were grown in vitro to confluence on culture-permeable supports and then co-cultured with either TNF-α or OPG. After exposure to either TNF-α or OPG, interleukin (IL)-8 protein and mRNA levels were evaluated. Ussing chamber, western blotting, real-time polymerase chain reaction, and immunofluorescence were used to further investigate the effect of OPG on intestinal barrier integrity and function.

RESULTS

Similar to TNF-α, treatment of monolayers with OPG caused increased monolayer permeability and diminished tight junction function and integrity, with loss of tight junction proteins from cell membranes. This was accompanied by elevated IL-8 protein and gene levels (P < 0.05). Western blotting also revealed that OPG, similar to TNF-α, induced NF-κB activation, as shown by inhibition of NF-κB kinase subunit-α phosphorylation.

CONCLUSIONS

These results indicate that OPG has pro-inflammatory properties because it induces gut barrier dysfunction and secretion of other pro-inflammatory cytokines. These results also provide evidence that OPG is likely to exert its pro-inflammatory effects through NF-κB activation and may potently contribute to IBD pathogenesis.

Oral Administration of Interleukin-10 and Anti-IL-1 Antibody Ameliorates Experimental Intestinal Inflammation

Background

To elucidate the effects of a solution containing interleukin-10 and anti-IL-1 antibody in modulating experimental intestinal inflammation.

Methods

Colitis was induced in BALB/c mice by oral administration of dextran sodium sulphate; mice were then treated with interleukin-10 plus anti-IL-1 antibody at low dosage. Transepithelial electrical resistance of isolated mouse colon and colon lengths were evaluated. Cytokines concentrations in organocultures supernatants and plasma samples were evaluated by Enzyme-Linked Immuno Sorbent Assay. Tight junction proteins were evaluated by immunofluorescence, respectively.

Results

Oral administration of tested products restores intestinal barrier function during experimental intestinal inflammation in association with reduced levels of proinflammatory cytokines, increased interleukin-10 plasma concentrations and a tight junction architecture restoration.

Conclusion

Obtained results may contribute to modelling an interesting strategy for the treatment of patients with inflammatory bowel diseases.

Physiologically based pharmacokinetic models for the optimization of antiretroviral therapy: recent progress and future perspective

Anti-HIV therapy is characterized by the chronic administration of antiretrovirals (ARVs), and consequently, several problems can arise during the management of HIV-positive patients. ARV disposition can be simulated by combining system data describing a population of patients and in vitro drug data through physiologically based pharmacokinetic (PBPK) models, which mathematically describe absorption, distribution, metabolism and elimination. PBPK modeling can find application in the investigation of clinically relevant scenarios, while providing the opportunity for a better understanding of the mechanisms regulating drug distribution. In this review, we have analyzed the most recent applications of PBPK models for ARVs and highlighted some of the most interesting areas of use, such as drug–drug interaction, pharmacogenetics, factors regulating absorption and tissue penetration, as well as therapy optimization in special populations. The application of the PBPK modeling approach might not be limited to the investigation of hypothetical clinical issues, but could be used to inform future prospective clinical trials.

Efficacy profiles for different concentrations of Lactobacillus acidophilus in experimental colitis

AIM: To determine the efficacy profiles of different concentrations of Lactobacillus acidophilus (L. acidophilus) for treating colitis using an experimental murine model.

METHODS: Colitis was established in 64 BALB/c mice by adding 5% dextran sodium sulfate (DSS) to the drinking water and allowing ad libitum access for 7 d. The mice were then randomly divided into the following control and experimental model groups (n = 8 each; day 0): untreated model control; negative-treatment model control (administered gavage of 1 mL/10 g normal saline); experimental-treatment models C4-C8 (administered gavage of 10⁴, 10⁵, 10⁶, 10⁷, or 10⁸ CFU/10 g L. acidophilus, respectively); positive-treatment model control (administration of the anti-inflammatory agent prednisone acetate at 45 μg/10 g). Eight mice given regular water (no DSS) and no subsequent treatments served as the normal control group. Body weight, fecal traits, and presence of fecal occult blood were assessed daily. All animals were sacrificed on post-treatment day 7 to measure colonic length, perform histological scoring, and quantify the major bacteria in the proximal and distal colon. Intergroup differences were determined by one-way ANOVA and post-hoc Student-Newman-Keuls comparison.

RESULTS: All treatments (L. acidophilus and prednisone acetate) protected against colitis-induced weight loss (P < 0.05 vs model and normal control groups). The extent of colitis-induced colonic shortening was significantly reduced by all treatments (prednisone acetate > C4 > C5 > C7 > C8 > C6; P < 0.05 vs untreated model group), and the C6 group showed colonic length similar to that of the normal control group (P > 0.05). The C6 group also had the lowest disease activity index scores among the model groups. The bacterial profiles in the proximal colon were similar between all of the experimental-treatment model groups (all P > 0.05). In contrast, the bacterial profile in the distal colon of the C6 group showed the distinctive features (P < 0.05 vs all other experimental-treatment model groups) of Lactobacillus sp. and Bifidobacterium sp. being the most abundant bacteria and Staphylococcus aureus being the least abundant bacteria.

CONCLUSION: The most therapeutically efficacious concentration of L. acidophilus (10⁶ CFU/10 g) may exert its effects by modulating the bacterial profile in the distal colon.

Association of gut microbiota with post-operative clinical course in Crohn's disease

Background

The gut microbiome is altered in Crohn’s disease. Although individual taxa have been correlated with post-operative clinical course, global trends in microbial diversity have not been described in this context.

Methods

We collected mucosal biopsies from the terminal ileum and ascending colon during surgery and post-operative colonoscopy in 6 Crohn’s patients undergoing ileocolic resection (and 40 additional Crohn’s and healthy control patients undergoing either surgery or colonoscopy). Using next-generation sequencing technology, we profiled the gut microbiota in order to identify changes associated with remission or recurrence of inflammation.

Results

We performed 16S ribosomal profiling using 101 base-pair single-end sequencing on the Illumina GAIIx platform with deep coverage, at an average depth of 1.3 million high quality reads per sample. At the time of surgery, Crohn’s patients who would remain in remission were more similar to controls and more species-rich than Crohn’s patients with subsequent recurrence. Patients remaining in remission also exhibited greater stability of the microbiota through time.

Conclusions

These observations permitted an association of gut microbial profiles with probability of recurrence in this limited single-center study. These results suggest that profiling the gut microbiota may be useful in guiding treatment of Crohn’s patients undergoing surgery.

Inflammatory bowel disease therapies and gut function in a colitis mouse model

Background. Exclusive enteral nutrition (EEN) is a well-established approach to the management of Crohn's disease. Aim. To determine effects of EEN upon inflammation and gut barrier function in a colitis mouse model. Methods. Interleukin-10-deficient mice (IL-10^−/−) were inoculated with Helicobacter trogontum and then treated with EEN, metronidazole, hydrocortisone, or EEN and metronidazole combination. Blood and tissue were collected at 2 and 4 weeks with histology, mucosal integrity, tight junction integrity, inflammation, and H. trogontum load evaluated. Results. H. trogontum induced colitis in IL-10^−/− mice with histological changes in the cecum and colon. Elevated mucosal IL-8 mRNA in infected mice was associated with intestinal barrier dysfunction indicated by decreased transepithelial electrical resistance and mRNA of tight junction proteins and increased short-circuit current, myosin light chain kinase mRNA, paracellular permeability, and tumor necrosis factor-α and myeloperoxidase plasma levels (P < 0.01 for all comparisons). EEN and metronidazole, but not hydrocortisone, treatments restored barrier function, maintained gut barrier integrity, and reversed inflammatory changes along with reduction of H. trogontum load (versus infected controls P < 0.05). Conclusion. H. trogontum infection in IL-10^−/− mice induced typhlocolitis with intestinal barrier dysfunction. EEN and metronidazole, but not hydrocortisone, modulate barrier dysfunction and reversal of inflammatory changes.

Intestinal mucosal permeability of children with cefaclor-associated serum sickness-like reactions

Although the serum sickness-like reaction (SSLR) in children after the administration of cefaclor has long been recognized, the exact mechanism of cefaclor-associated SSLR remains unclear. This study aims to investigate the association between intestinal mucosal permeability and cefaclor-associated SSLR in children. A total of 82 pediatric patients with upper respiratory tract infection following the cefaclor therapy was divided into cefaclor-associated SSLR positive group and negative group based on the presence or absence of SSLR after taking cefaclor, and 30 healthy volunteers served as control group. Urinary lactulose/mannitol (L/M) ratios and serum diamine oxidase (DAO) levels were determined in all cases on days 7, 9, 11, 13, and 15 after oral administration of cefaclor. The children in the control group were given the same measurements after enrollment in this study. From days 7 to 13, the urinary L/M ratio of children with cefaclor SSLR gradually increased and reached to the highest level of 0.38 ± 0.14 on day 13. Compared with the cefaclor-associated SSLR negative group and control group, urinary L/M ratios increased significantly in the cefaclor SSLR positive group on days 7, 9, 11, 13, and 15 after taking cefaclor, and serum levels of DAO following the treatment of cefaclor increased significantly in children with cefaclor SSLR on days 9, 11, 13, and 15. No significant difference in urinary L/M ratios and serum levels of DAO between SSLR negative group and control group through the entire experiment was observed. In conclusion, administration of cefaclor may induce SSLR in children by increasing the intestinal mucosal permeability and/or affecting the integrity of the intestinal mucosa. Determinations of urinary L/M ratios and serum DAO levels may be helpful for observing or predicting the occurrence of SSLR after administration of cefaclor, which will encourage physicians to proceed with extreme caution when prescribing cefaclor for pediatric patients.