Review article: Role of the enteric microflora in the pathogenesis of intestinal inflammation and arthritis

Efficacy of Probiotics in Rheumatoid Arthritis and Spondyloarthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: We aimed to provide a systematic review and meta-analysis of randomized controlled trials assessing the effect of probiotics supplementation on symptoms and disease activity in patients with chronic inflammatory rheumatic diseases (rheumatoid arthritis (RA), spondylarthritis (SpA), or psoriatic arthritis). Methods: A systematic literature review and meta-analysis from RA and SpA randomized controlled trials were conducted searching for articles in MEDLINE/PubMed and abstracts from recent international rheumatology meetings. The control group was a placebo or another dietary intervention. The risk of bias of the selected studies was evaluated using the Cochrane Collaboration tool and the Jadad scale. Results: The initial search yielded 173 articles. Of these, 13 studies were included in the qualitative synthesis, 8 concerning a total of 344 RA patients and 2 concerning a total of 197 SpA patients. Three meta-analyses were also analyzed. Probiotic strains and quantities used were different among trials (5 studies using Lactobacillus sp., 1 trial Bacillus coagulans and the others a mix of different probiotic strains). Time to assess response ranged from 8 weeks to one year. Two studies associated probiotic supplementation with a dietary intervention. Meta-analysis showed a statistically significant decrease of C-reactive protein (CRP) concentration (mean difference (MD)) −3.04 (95% CI −4.47, −1.62) mg/L, p < 0.001; I² = 20%, n patients = 209) with probiotics in RA. However, after excluding high-risk-of-bias trials of meta-analysis, there was no difference between probiotics and placebo on DAS28 (standard MD −0.54; 95% CI −1.94 to 0.85, p = 0.45, I² 93%, n patients = 143). The two studies on SpA patients showed no efficacy of probiotics. Conclusions: Probiotic supplementation might decrease RA activity with a moderate decrease effect on CRP, but lack of evidence and studies’ heterogeneity do not allow us to propose them to patients with inflammatory arthritis to control their disease. Further RCTs are required in the future to determinate the efficacy of probiotics and the optimal administration design.

Diet and Inflammatory Bowel Disease: What Quality Standards Should Be Applied in Clinical and Laboratory Studies?

Many patients suffering from inflammatory bowel disease (IBD) follow restrictive diets, as many respective recommendations circulate. Efforts are made to evaluate and summarize the published information, for example, in a recent consensus manuscript by the International Organization for the Study of IBD (IOIBD). However, the standards that should be applied to make claims about dietary effects are poorly defined. In this manuscript, the scientific basis of recommendations for nutritional interventions in IBD is analyzed. Epidemiological evidence on diet in IBD is always biased by numerous factors, and the number of robust dietary intervention studies is limited due to methodological difficulties. Therefore, animal models are used to test hypotheses with respect to dietary factors and intestinal inflammation. Naturally, animal models have limitations, and knowledge of key characteristics of colitis animal models is crucial to understand their advantages and disadvantages. In recent years the important role of the microbiota for IBD and dietary factors has been discovered. Microbiota data are added to many publications on IBD and nutrition. The quality of those data varies largely. Subsequently, quality standards for microbiota analyses also are discussed. Finally, quality requirements to be applied on recommendations for dietary changes in patients with IBD are suggested.

Comparative analysis of microbial community structure between healthy and Aeromonas veronii-infected Yangtze finless porpoise

Background

The gut microbiota is a complex ecosystem, which is essential for the metabolism, health and immunity of host. Many diseases have been shown to be closely related to the alteration of intestinal flora. Aeromonas veronii as a conditioned pathogen can cause disease in Yangtze finless porpoise through intestinal infections. However, it is not clear whether the disease caused by Aeromonas veronii is related to changes of intestinal flora. In the current study, the diversity and composition of gut microbiota in the healthy and Aeromonas veronii-infected Yangtze finless porpoise were evaluated by high-throughput sequencing to further investigate the potential association between intestinal flora alteration and pathogen invasion.

Results

A total of 127,3276 high-quality sequences were achieved and 2465 operational taxonomic units (OTUs) were in common among all samples. The results of alpha diversity showed that there was no obvious difference in richness and diversity between healthy and Aeromonas veronii-infected Yangtze finless porpoise. Firmicutes, Bacteroidetes and Proteobacteria were the most dominant phyla in all samples. In addition, the healthy Yangtze finless porpoise exhibited higher abundance of Firmicutes and Fusobacteria than Aeromonas veronii-infected Yangtze finless porpoise, while, the level of Proteobacteria was decreased. At the genus level, Paeniclostridium and Paraclostridium were the predominant bacteria genera in the CK (healthy Yangtze finless porpoise) group. In the DIS (Aeromonas veronii-infected Yangtze finless porpoise) group, Lactobacillus and unidentified_Enterobacteriaceae were the dominant bacteria genera and the proportion of Paeniclostridium, Paraclostridium, Terrisporobacter, Cetobacterium, Candidatus Arthromitus, Terrabacter and Dechloromonas were reduced.

Conclusions

In conclusion, our results showed that Aeromonas veronii infection can alter the gut microbiota of the Yangtze finless porpoise by affecting the number of harmful bacteria and beneficial bacteria.

Bifidobacterium longum Suppresses Murine Colorectal Cancer through the Modulation of oncomiRs and Tumor Suppressor miRNAs

The modulatory role of the Bifidobacterium longum (BL), isolated from women breast milk, on some oncogenic and tumor suppressor miRNAs as well as IL-1β and IL6 targeted-miRNAs was investigated using murine colorectal cancer (CRC) induced on the top of inflammatory ulcerative colitis model. The investigation of the oncomiRs miR-21a and miR-155, which regulate IL-6 and IL-1β expression, indicated that both was depressed by BL-administration in healthy and in CRC-mice. BL-administration induced the tumor suppressor miRNAs (miR-145 and miR-15a) expression in both of the healthy and in CRC-mice. The miR-146a expression, which regulates both of IL-1β and IL-6 expression, was decreased after the BL-administration in both of the healthy and in CRC-mice. In CRC-mice, NF-Kb concentration was elevated, however this NF-Kb induction was diminished after the treatment with BL. BL highly enhanced the IL-1β and IL-6 mRNA and protein concentrations in healthy mice. The administration of BL to CRC-mice resulted in a dramatic increase in IL-1β mRNA and IL-1β concentration, which in contrast was accompanied with a decrease in the IL-6 mRNA and IL-6 concentration. BL-administration resulted in a drop in the aberrant crypt foci number in CRC-mice and increased necrosis and fibrosis of the colon cells. The modulatory influence of B. longum on microRNAs may provide an important therapeutic impact in CRC through inhibition of the proliferation, invasion, apoptosis, and cell cycle of tumor cells.

Infection by the parasitic helminth Trichinella spiralis activates a Tas2r-mediated signaling pathway in intestinal tuft cells

Intestinal tuft cells are sentinels monitoring the luminal contents and play a critical role in type 2 immunity. In this work, Trichinella spiralis excretion–secretion and extract were shown to directly induce interleukin 25 (IL-25) release from the intestinal villi, evoke calcium responses in tuft cells, and activate Tas2r bitter-taste receptors, whereas the bitter compound salicin was shown to activate and induce tuft cells to release IL-25. Gα-gustducin/Gβ1γ13 and/or Gαo/Gβ1γ13, Plcβ2, Ip₃r2, and Trpm5 comprise the signal transduction pathways that tuft cells utilize to initiate type 2 immune responses. Potentiation of Trpm5 by a natural sweet compound, stevioside, can enhance the tuft cell–ILC2 circuit’s activity, indicating that modulating these signaling components can help devise new means of combating parasites.

The parasitic helminth Trichinella spiralis, which poses a serious health risk to animals and humans, can be found worldwide. Recent findings indicate that a rare type of gut epithelial cell, tuft cells, can detect the helminth, triggering type 2 immune responses. However, the underlying molecular mechanisms remain to be fully understood. Here we show that both excretory–secretory products (E–S) and extract of T. spiralis can stimulate the release of the cytokine interleukin 25 (IL-25) from the mouse small intestinal villi and evoke calcium responses from tuft cells in the intestinal organoids, which can be blocked by a bitter-taste receptor inhibitor, allyl isothiocyanate. Heterologously expressed mouse Tas2r bitter-taste receptors, the expression of which is augmented during tuft-cell hyperplasia, can respond to the E–S and extract as well as to the bitter compound salicin whereas salicin in turn can induce IL-25 release from tuft cells. Furthermore, abolishment of the G-protein γ13 subunit, application of the inhibitors for G-protein αo/i, Gβγ subunits, and phospholipase Cβ2 dramatically reduces the IL-25 release. Finally, tuft cells are found to utilize the inositol triphosphate receptor type 2 (Ip₃r2) to regulate cytosolic calcium and thus Trpm5 activity, while potentiation of Trpm5 by a sweet-tasting compound, stevioside, enhances tuft cell IL-25 release and hyperplasia in vivo. Taken together, T. spiralis infection activates a signaling pathway in intestinal tuft cells similar to that of taste-bud cells, but with some key differences, to initiate type 2 immunity.

Proteomics in Inflammatory Bowel Disease: Approach Using Animal Models

Recently, proteomics studies have provided important information on the role of proteins in health and disease. In the domain of inflammatory bowel disease, proteomics has shed important light on the pathogenesis and pathophysiology of inflammation and has contributed to the discovery of some putative clinical biomarkers of disease activity. By being able to obtain a large number of specimens from multiple sites and control for confounding environmental, genetic, and metabolic factors, proteomics studies using animal models of colitis offered an alternative approach to human studies. Our aim is to review the information and lessons acquired so far from the use of proteomics in animal models of colitis. These studies helped understand the importance of different proteins at different stages of the disease and unraveled the different pathways that are activated or inhibited during the inflammatory process. Expressed proteins related to inflammation, cellular structure, endoplasmic reticulum stress, and energy depletion advanced the knowledge about the reaction of intestinal cells to inflammation and repair. The role of mesenteric lymphocytes, exosomes, and the intestinal mucosal barrier was emphasized in the inflammatory process. In addition, studies in animal models revealed mechanisms of the beneficial effects of some therapeutic interventions and foods or food components on intestinal inflammation by monitoring changes in protein expression and paved the way for some new possible inflammatory pathways to target in the future. Advances in proteomics technology will further clarify the interaction between intestinal microbiota and IBD pathogenesis and investigate the gene-environmental axis of IBD etiology.

TLR signaling at the intestinal epithelial interface

The intestinal epithelium provides a critical interface between lumenal bacteria and the mucosal immune system. Whereas normal commensal flora do not trigger acute inflammation, pathogenic bacteria trigger a potent inflammatory response. Our studies emanate from the hypothesis that the intestinal epithelium is normally hyporesponsive to commensal pathogen-associated molecular patterns (PAMPs) such as LPS. Our data demonstrate that normal human colonic epithelial cells and lamina propria cells express low levels of TLR4 and its co-receptor MD-2. This expression pattern is mirrored by intestinal epithelial cell (IEC) lines. Co-expression of TLR4 and MD-2 is necessary and sufficient for LPS responsiveness in IEC. Moreover, LPS sensing occurs along the basolateral membrane of polarized IEC in culture. Expression of MD-2 is regulated by IFN-γ. Cloning of the MD-2 promoter demonstrates that promoter activity is increased by IFN-γ and blocked by the STAT inhibitor SOCS3. We conclude from our studies that the intestinal epithelium down-regulates expression of TLR4 and MD-2 and is LPS unresponsive. The Th1 cytokine IFN-γ up-regulates expression of MD-2 in a STAT-dependent fashion. The results of our studies have important implications for understanding human inflammatory bowel diseases.

The effects of orally administered Bacillus coagulans and inulin on prevention and progression of rheumatoid arthritis in rats

BACKGROUND

Probiotics have been considered as an approach to addressing the consequences of different inflammatory disorders. The spore-forming probiotic strain Bacillus coagulans has demonstrated anti-inflammatory and immune-modulating effects in both animals and humans. The prebiotic inulin also potentially affects the immune system as a result of the change in the composition or fermentation profile of the gastrointestinal microbiota.

OBJECTIVE

In the present study, an in vivo model was conducted to investigate the possible influences of probiotic B. coagulans and prebiotic inulin, both in combination and/or separately, on the downregulation of immune responses and the progression of rheumatoid arthritis (RA), using arthritis-induced rat model.

DESIGN

Forty-eight healthy male Wistar rats were randomly categorized into six experimental groups as follows: 1) control: normal healthy rats fed with standard diet, 2) disease control (RA): arthritis-induced rats fed with standard diet, 3) prebiotic (PRE): RA+ 5% w/w long-chain inulin, 4) probiotic (PRO): RA+ 10(9) spores/day B. coagulans by orogastric gavage, 5) synbiotic (SYN): RA+ 5% w/w long-chain inulin and 10(9) spores/day B. coagulans, and 6) treatment control: (INDO): RA+ 3 mg/kg/day indomethacin by orogastric gavage. Feeding with the listed diets started on day 0 and continued to the end of study. On day 14, rats were injected with complete Freund's adjuvant (CFA) to induce arthritis. Arthritis activity was evaluated by the biochemical parameters and paw thickness. Biochemical assay for fibrinogen (Fn), serum amyloid A (SAA), and TNF-α and alpha-1-acid glycoprotein (α1AGp) was performed on day 21, 28, and 35 (7, 14 and 21 days post RA induction), respectively.

RESULTS

Pretreatment with PRE, PRO, and SYN diets significantly inhibits SAA and Fn production in arthritic rats (P < 0.001). A significant decrease in the production of pro-inflammatory cytokines, such as TNF-α, was seen in the PRE, PRO, and SYN groups (P < 0.001), which was similar to the anti-inflammatory effect of indomethacin. Furthermore, no significant anti-inflammatory effects were observed following different treatments using α1 AGp as an RA indicator. Pretreatment with all supplied diets significantly inhibited the development of paw swelling induced by CFA (P < 0.001).

CONCLUSION

The results of this study indicate that the oral intake of probiotic B. coagulans and prebiotic inulin can improve the biochemical and clinical parameters of induced RA in rat.

Overexpression of miR-595 and miR-1246 in the sera of patients with active forms of inflammatory bowel disease

BACKGROUND

MicroRNAs (miRNAs) are dysregulated in the inflammatory bowel diseases, Crohn's disease (CD) and ulcerative colitis (UC), which arise due to dysfunctional host-microbe interactions and impairment of the barrier function of the intestine. Here, we sought to determine whether circulating miRNAs are biomarkers of active colonic CD and UC and can provide insights into disease pathogenesis. Comparison was made with serum miRNAs in patients with rheumatoid arthritis (RA).

METHODS

Total serum RNA from patients with colonic CD, UC, and RA, and normal healthy adults was screened for disease-associated miRNAs by microarray analysis, with subsequent validation by quantitative reverse-transcription polymerase chain reaction. MiRNA targets were identified by luciferase reporter assays.

RESULTS

MiR-595 and miR-1246 were significantly upregulated in the sera of active colonic CD, UC, and RA patients, compared with healthy subjects; and in active colonic CD and UC compared with inactive disease. Luciferase reporter assays indicated that miR-595 inhibits the expression of neural cell adhesion molecule-1 and fibroblast growth factor receptor 2.

CONCLUSIONS

Serum miR-595 and miR-1246 are biomarkers of active CD, UC, and RA. These findings gain significance from reports that miR-595 impairs epithelial tight junctions, whereas miR-1246 indirectly activates the proinflammatory nuclear factor of activated T cells. miR-595 targets the cell adhesion molecule neural cell adhesion molecule-1, and fibroblast growth factor receptor 2, which plays a key role in the differentiation, protection, and repair of colonic epithelium, and maintenance of tight junctions. miR-595 and miR-1246 warrant testing as potential targets for therapeutic intervention in the treatment of inflammatory bowel disease.

The involvement of gut microbiota in inflammatory bowel disease pathogenesis: potential for therapy

Over the past recent years, a great number of studies have been directed toward the evaluation of the human host-gut microbiota interaction, with the goal to progress the understanding of the etiology of several complex diseases. Alterations in the intestinal microbiota associated with inflammatory bowel disease are well supported by literature data and have been widely accepted by the research community. The concomitant implementation of high-throughput sequencing techniques to analyze and characterize the composition of the intestinal microbiota has reinforced the view that inflammatory bowel disease results from altered interactions between gut microbes and the mucosal immune system and has raised the possibility that some form of modulation of the intestinal microbiota may constitute a potential therapeutic basis for the disease. The aim of this review is to describe the changes of gut microbiota in inflammatory bowel disease, focusing the attention on its involvement in the pathogenesis of the disease, and to review and discuss the therapeutic potential to modify the intestinal microbial population with antibiotics, probiotics, prebiotics, synbiotics and fecal microbiota transplantation.

Antimicrobial peptides and gut microbiota in homeostasis and pathology

We survive because we adapted to a world of microorganisms. All our epithelial surfaces participate in keeping up an effective barrier against microbes while not initiating ongoing inflammatory processes and risking collateral damage to the host. Major players in this scenario are antimicrobial peptides (AMPs). Such broad-spectrum innate antibiotics are in part produced by specialized cells but also widely sourced from all epithelia as well as circulating inflammatory cells. AMPs belong to an ancient defense system found in all organisms and participated in a preservative co-evolution with a complex microbiome. Particularly interesting interactions between host barrier and microbiota can be found in the gut. The intestinal cell lining not only has to maintain a tightly regulated homeostasis during its high-throughput regeneration, but also a balanced relationship towards an extreme number of mutualistic or commensal inhabitants. Recent research suggests that advancing our understanding of the circumstances of such balanced and sometimes imbalanced interactions between gut microbiota and host AMPs should have therapeutic implications for different intestinal disorders.

Metabolomic profiles are gender, disease and time specific in the interleukin-10 gene-deficient mouse model of inflammatory bowel disease

Metabolomic profiling can be used to study disease-induced changes in inflammatory bowel diseases (IBD). The aim of this study was to investigate the difference in the metabolomic profile of males and females as they developed IBD. Using the IL-10 gene-deficient mouse model of IBD and wild-type mice, urine at age 4, 6, 8, 12, 16, and 20 weeks was collected and analyzed by nuclear magnetic resonance (NMR) spectroscopy. Multivariate data analysis was employed to assess differences in metabolomic profiles that occurred as a consequence of IBD development and severity (at week 20). These changes were contrasted to those that occurred as a consequence of gender. Our results demonstrate that both IL-10 gene-deficient and wild-type mice exhibit gender-related changes in urinary metabolomic profile over time. Some male-female separating metabolites are common to both IL-10 gene-deficient and control wild-type mice and, therefore, appear to be related predominantly to gender maturation. In addition, we were able to identify gender-separating metabolites that are unique for IL-10 gene-deficient and wild-type mice and, therefore, may be indicative of a gender-specific involvement in the development and severity of the intestinal inflammation. The comparison of the gender-separating metabolomic profile from IL-10 gene-deficient mice and wild-type mice during the development of IBD allowed us to identify changes in profile patterns that appear to be imperative in the development of intestinal inflammation, but yet central to gender-related differences in IBD development. The knowledge of metabolomic profile differences by gender and by disease severity has potential clinical implications in the design of both biomarkers of disease as well as the development of optimal therapies.

Probiotics can generate FoxP3 T-cell responses in the small intestine and simultaneously inducing CD4 and CD8 T cell activation in the large intestine

Most studies on probiotics aim to restore intestinal homeostasis to reduce immune-pathology in disease. Of equal importance are studies on how probiotics might prevent or delay disease in healthy individuals. However, knowledge on mechanisms of probiotic actions in healthy individuals is scarce. To gain more insight in how different bacterial strains may modulate the healthy intestinal immune system, we investigated the effect of the food derived bacterial strains L. plantarum WCFS1, L. salivarius UCC118, and L. lactis MG1363, on the intestinal regulatory immune phenotype in healthy mice. All three bacterial strains induced an upregulation of activity and numbers of CD11c⁺ MHCII⁺ DCs in the immune-sampling Peyer’s Patches. Only L. salivarius UCC118 skewed towards an immune regulatory phenotype in the small intestinal lamina propria (SILP). The effects were different in the large intestine lamina propria. L. salivarius UCC118 induced activation in both CD4 and CD8 positive T-cells while L. plantarum WCFS1 induced a more regulatory phenotype. Moreover, L. plantarum WCFS1 decreased the Th1/Th2 ratio in the SILP. Also L. lactis MG1363 had immunomodulatory effects. L. lactis MG1363 decreased the expression of the GATA-3 and T-bet in the SILP. As our data show that contradictory effects may occur in different parts of the gut, it is recommended to study effects of probiotic in different sites in the intestine. Our strain-specific results suggest that unspecified application of probiotics may not be very effective. Our data also indicate that selection of specific probiotic strain activities on the basis of responses in healthy mice may be a promising strategy to specifically stimulate or suppress immunity in specific parts of the intestine.

[Rescue therapy with sulfasalazine prior to immunosuppressive or biological agents in ulcerative colitis poorly controlled with mesalazine]

INTRODUCTION

In ulcerative colitis, aminosalicylates are the mainstay of maintenance therapy. Sulfasalazine was the first aminosalicylic used in the maintenance therapy of this disease. Later, mesalazine was preferred due to its supposedly better tolerability. However, recent studies indicate certain benefits of the use of sulfasalazine because of its possible superior effectiveness. The aim of this study was to determine whether patients with ulcerative colitis poorly controlled by mesalazine as maintenance therapy respond to sulfasalazine, thus avoiding the use of immunosuppressive or biological therapies.

METHODS

The Inflammatory Bowel Disease Clinic of the Ramón y Cajal Hospital maintains a database in which all drug exposures are registered. We selected patients poorly controlled with mesalazine who had received sulfasalazine as rescue maintenance therapy. We determined the percentage of patients poorly controlled with mesalazine who responded to sulfasalazine.

RESULTS

Of 415 patients with ulcerative colitis, 49 had been treated with sulfasalazine at some time. Of these, sulfasalazine was selected as an alternative therapy due to poor disease control with mesalazine. The median duration of mesalazine therapy until the switch was 20.8 months, with a median dose of 3.35 g/day. In 21 of the 31 patients (67.7%), sulfasalazine was able to control symptoms and maintain remission.

CONCLUSION

Despite the limitations of this study, we found that 67.7% of patients with ulcerative colitis poorly controlled with mesalazine responded to a switch to sulfasalazine. These patients would normally have progressed to immunosuppressive, biological or surgical treatments. This option merits further studies. Meanwhile sulfasalazine should not be forgotten in the management of ulcerative colitis.

Phylogenetic analysis of 16S rRNA gene sequences reveals distal gut bacterial diversity in wild wolves (Canis lupus)

The aim of this study was to describe the microbial communities in the distal gut of wild wolves (Canis lupus). Fecal samples were collected from three healthy unrelated adult wolves captured at the nearby of Dalai Lake Nature Reserve in Inner Mongolia of China. The diversity of fecal bacteria was investigated by constructing PCR-amplified 16S rRNA gene clone libraries using the universal bacterial primers 27 F and 1493 R. A total of 307 non-chimeric near-full-length 16S rRNA gene sequences were analyzed and 65 non-redundant bacteria phylotypes (operational taxonomical units, OTUs) were identified. Seventeen OTUs (26%) showed less than 98% sequence similarity to 16S rRNA gene sequences were reported previously. Five different bacterial phyla were identified, with the majority of OTUs being classified within the phylum Firmicutes (60%), followed by Bacteroidetes (16.9%), Proteobacteria (9.2%), Fusobacteria (9.2%) and Actinobacteria (4.6%). The majority of clones fell within the order Clostridiales (53.8% of OTUs). It was predominantly affiliated with five families: Lachnospiraceae was the most diverse bacterial family in this order, followed by Ruminococcaceae, Clostridiaceae, Peptococcaceae and Peptostreptococcaceae.

Bacillus coagulans: a viable adjunct therapy for relieving symptoms of rheumatoid arthritis according to a randomized, controlled trial

BACKGROUND

Lactic acid-producing bacteria (LAB) probiotics demonstrate immunomodulating and anti-inflammatory effects and the ability to lessen the symptoms of arthritis in both animals and humans. This randomized, double-blind, placebo-controlled, parallel-design, clinical pilot trial was conducted to evaluate the effects of the LAB probiotic preparation, Bacillus coagulans GBI-30, 6086, on symptoms and measures of functional capacity in patients with rheumatoid arthritis (RA) in combination with pharmacological anti-arthritic medications.

METHODS

Forty-five adult men and women with symptoms of RA were randomly assigned to receive Bacillus coagulans GBI-30, 6086 or placebo once a day in a double-blind fashion for 60 days in addition to their standard anti-arthritic medications. Arthritis activity was evaluated by clinical examination, the American College of Rheumatology (ACR) criteria, the Stanford Health Assessment Questionnaire Disability Index (HAQ-DI), and laboratory tests for erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).

RESULTS

Subjects who received Bacillus coagulans GBI-30, 6086 experienced borderline statistically significant improvement in the Patient Pain Assessment score (P = .052) and statistically significant improvement in Pain Scale (P = .046) vs placebo. Compared with placebo, Bacillus coagulans GBI-30, 6086 treatment resulted in greater improvement in patient global assessment and self-assessed disability; reduction in CRP; as well as the ability to walk 2 miles, reach, and participate in daily activities. There were no treatment-related adverse events reported throughout this study.

CONCLUSIONS

Results of this pilot study suggest that adjunctive treatment with Bacillus coagulans GBI-30, 6086 LAB probiotic appeared to be a safe and effective for patients suffering from RA. Because of the low study population size, larger trials are needed to verify these results.

TRIAL REGISTRATION

ACTRN12609000435280.

Childhood Inflammatory Bowel Disease in Libya: Epidemiological and Clinical features

Background & Aims: Inflammatory bowel disease is thought to be rare in Libya. The aim is to determine the prevalence of juvenile onset inflammatory bowel disease in Libya. Setting: Al-Fateh childrens' hospital, Benghazi, Libya. Methods: This is a retrospective study of all cases diagnosed over 10 years (1997–2006) with either ulcerative colitis, Crohn's disease or indeterminate colitis. Inclusion criteria were age <15 years at time of presentation who were resident in the eastern part of the country and who diagnosed with inflammatory bowel disease. Clinical features were outlined using a proforma. Results: Sixteen cases were diagnosed with inflammatory bowel disease, of whom 11 were males (M:F ratio of 1.5:1). The prevalence and incidence rates in the year 2006 were 3.6 and 0.9 per 100,000 children, respectively. The incidence rate increased from 0.2 in 2002 to 0.9 in 2006 (Z score of 39.87, p= 0.00). The age at presentation ranged from 5 months to 14 years. Nine had Crohn's disease (6 males) and 6 had ulcerative colitis (4 males). One patient had indeterminate colitis. The most common clinical features were diarrhea in 10 (62.5%), abdominal pain, anorexia and weight loss in 9 (56.2%), anemia in 7 (43.75%) and vomiting in 6 (37%). Ileopancolitis was found in 3 patients whereas 6 patients had ileocecal disease. Conclusions: Childhood inflammatory bowel disease in this population is not so rare and it is increasing. The clinical pattern is similar to that reported by others.

A meta-analysis of the efficacy of sulfasalazine in comparison with 5-aminosalicylates in the induction of improvement and maintenance of remission in patients with ulcerative colitis

BACKGROUND

Historically, sulfasalazine (SSZ) and 5-aminosalicylates (5-ASAs) have been a mainstay of mild-to-moderate ulcerative colitis (UC) remission induction and maintenance therapy. Considering the pivotal role of intestinal microbial flora in pathophysiology of UC and antimicrobial activity of sulfapyridine, we hypothesized that SSZ might be more effective than 5-ASAs in the management of UC.

AIM

To compare the efficacy and tolerability of SSZ with each of the 5-ASAs (mesalamine, olsalazine, and balsalazide) by a meta-analysis technique.

METHODS

Pubmed, Embase, Scopus, Web of Science, and Cochrane Central Register of Controlled Trials were searched for studies compared efficacy and/or tolerability of SSZ with 5-ASAs in the management of UC. The search terms were: "sulfasalazine" or "sulfasalazine" and "5-aminosalicylic acid," "mesalazine," "mesalamine," "olsalazine" or "balsalazide" and "ulcerative colitis." Data were collected from 1966 to April 2008. There was no language restriction. "Overall improvement," "relapse rate," "total adverse events," and "withdrawals because of adverse events" were the key outcomes of interest.

RESULTS

Twenty randomized placebo controlled trials met our criteria and were included in the meta-analysis. Comparison of SSZ with mesalamine yielded a nonsignificant relative risk (RR) of 1.04 (95% confidence interval of 0.89-1.21, P = 0.63) for overall improvement, a nonsignificant RR of 0.98 (95% CI 0.78-1.23, P = 0.85) for relapse, a nonsignificant RR of 0.76 (95% CI 0.54-1.07, P = 0.11) for any adverse events, and a nonsignificant RR of 0.78 (95% CI 0.46-1.3, P = 0.33) for withdrawals due to adverse events. Comparison of SSZ with olsalazine yielded a nonsignificant RR of 1.14 (95% CI 0.91-1.43, P = 0.25) for overall improvement, a nonsignificant RR of 0.93 (95% CI 0.77-1.12, P = 0.42) for relapse, a nonsignificant RR of 1.21 (95% CI 0.9-1.61, P = 0.20) for any adverse events, and a nonsignificant RR of 1.53 (95% CI 0.93-2.52, P = 0.09) for withdrawals due to adverse events. Comparison of SSZ with balsalazide yielded a nonsignificant RR of 1.3 (95% CI 0.93-1.81, P = 0.12) for overall improvement, and a significant RR of 0.17 (95% CI 0.06-0.49, P = 0.001) for withdrawals because of adverse events.

CONCLUSION

SSZ does not differ from mesalamine or olsalazine in terms of efficacy and tolerability in UC. Withdrawal from study due to adverse events was significantly lower for balsalazide compared with SSZ. Convincing conclusions on the comparison of effectiveness and safety of balsalazide and SSZ in UC remains to be elucidated by further clinical trials. Considering the lower cost of treatment with SSZ and the equal rate of adverse events with other 5-ASAa, it is not surprising to suggest SSZ as a first-choice treatment for UC and reserve 5-ASAs for when SSZ intolerability occurs.

Lactobacillus casei suppresses experimental arthritis by down-regulating T helper 1 effector functions

Although the beneficial effects of probiotics on wide variety of diseases have been shown, little is known about how probiotics modulate the immune system. In this study we elucidated the underlying mechanisms how Lactobacillus casei (L. casei) protects against rheumatoid arthritis (RA) progression by investigating the effector functions of CD4(+) T cells. Oral administration of L. casei suppressed collagen-induced arthritis (CIA) and reduced paw swelling, lymphocyte infiltration and destruction of cartilage tissue. L. casei administration reduced type II collagen (CII)-reactive proinflammatory molecules (IL-1beta, IL-2, IL-6, IL-12, IL-17, IFN-gamma, TNF-alpha and Cox-2) by CD4(+) T cells. L. casei administration also reduced translocation of NF-kappaB into nucleus and CII-reactive Th1-type IgG isotypes IgG2a and IgG2b, while up-regulating immunoregulatory IL-10 levels. Our results suggest that oral administration of L. casei suppresses the type II collagen-reactive effector function of Th1-type cellular and humoral immune responses in arthritic inflammation.

Genome-wide expression profiling during protection from colitis by regulatory T cells

BACKGROUND

In the adoptive transfer model of colitis it has been shown that regulatory T cells (Treg) can hinder disease development and cure already existing mild colitis. The mechanisms underlying this regulatory effect of CD4(+)CD25(+) Tregs are not well understood.

METHODS

To identify pathways of importance for immune regulation in protected mice we studied the genome-wide expression profile in the inflamed rectum of SCID mice with CD4(+) T cell transfer colitis and in the uninflamed rectum of mice protected from colitis by Treg cells. We used DNA microarray technology (Affymetrix GeneChip Mouse Genome 430 2.0 Array), which enabled an analysis of a complete set of RNA transcript levels in each sample. Array results were confirmed by real-time reverse-transcriptase polymerase chain reaction (RT-PCR).

RESULTS

Data were analyzed using combined projections to latent structures and functional annotation analysis. The colitic samples were clearly distinguishable from samples from normal mice by a vast number of inflammation- and growth factor-related transcripts. In contrast, the Treg-protected animals could not be distinguished from either the normal BALB/c mice or the normal SCID mice. mRNA expression profiles of cytokine, chemokine, and growth factor genes were significantly altered in colitic as opposed to noncolitic mice. In particular, the transcription factors STAT3, GATA2, and NFkappaB, the cytokine IL1beta, and the chemokine receptors CXCR3 and CCR1 as well as their ligands all seemingly play central roles in the inflammatory processes.

CONCLUSIONS

We suggest that these molecules alone or in combination could be future therapeutic targets.

Defensins and other antimicrobial peptides in inflammatory bowel disease

PURPOSE OF REVIEW

Recently published studies presenting novel and relevant information on defensins and other antimicrobial peptides in Crohn's disease and ulcerative colitis are reviewed.

RECENT FINDINGS

Different clinical localizations of Crohn's disease are associated with different deficiencies in epithelial and leukocyte antimicrobial peptide expression. As compared with ulcerative colitis, Crohn's disease of the colon is characterized by an impaired induction of beta defensins, and antimicrobial antiproteases elafin and SLPI, as well as the cathelicidin LL37. The attenuated induction of beta defensins is linked to fewer gene copy numbers in this locus, which is associated with colonic but not ileal Crohn's disease. In contrast, ileal Crohn's disease patients are characterized by a reduced antibacterial activity and a specific reduction of ileal Paneth cell defensins. This decrease is independent of the grade of histological inflammation and cannot be found in inflammation controls. Thus, some of these defects can be explained either by direct or indirect genetic mechanisms and appear to be primary.

SUMMARY

Unlike ulcerative colitis, ileal and colonic Crohn's disease are characterized by localized deficiencies of antibacterial peptides. Understanding the precise molecular mechanisms of the defective antibacterial barrier function might provide new therapeutic directions.

Lactobacilli, bifidobacteria and E. coli nissle induce pro- and anti-inflammatory cytokines in peripheral blood mononuclear cells

AIM: To investigate whether the stimulation of peripheral blood mononuclear cells (PBMNC) with the cell debris and cell extraction of different probiotic strains is similar or species specific.

METHODS: Three strains of bifidobacteria, 4 strains of lactobacilli, and E. coli nissle were sonicated and centrifuged in order to divide them into cell extract and cell debris. PBMNC were separated by density gradient and incubated for 36 h with either the cell debris or the cell extract of single strains of probiotic bacteria in doses from 10² to 10⁸ CFU/mL. Cell supernatants were taken and interleukin (IL)-10, IL-1β, and tumor necosis factor (TNF)-α were determined by ELISA.

RESULTS: Depending on the species super-family, the strains had different stimulation patterns. Except for both L. casei strains, the cell extract of bifidobacteria and lactobacilli had less stimulating capacity than cell debris, whereas the cell extract of E. coli nissle had similar stimulating properties to that of the cell debris of the strain and significantly more stimulating capacity than that of bifidobacteria and lactobacilli. The cell debris of bifidobacteria stimulated more cytokine release than the cell debris of lactobacilli. The cell debris of lactobacilli did not have a stimulating capacity when lower concentrations were used. Neither cell extraction nor cell debris had an inhibitory effect on the production of the tested cytokines by stimulated PBMNC.

CONCLUSION: The incubation of probiotic strains, which have been used in clinical trials for inflammatory diseases, with immunocompetent cells leads to different species specific reactions. High IL-10 response to cell debris of bifidobacteria and E. coli nissle can be found. This corresponds to positive effects of bifidobacteria and E. coli nissle in clinical trials for inflammatory bowel disease compared to negative outcomes obtained with lactobacilli.

A traditional Japanese medicine mitigates TNBS-induced colitis in rats

OBJECTIVE

Differences in dietary habits may be one of the reasons that the incidence of inflammatory bowel disease has remained lower in Japan than in Western countries. We investigated whether a traditional Japanese medicine (Strong Wakamto), based on Aspergillus oryzae koji, would exert any effect on experimental colitis in rats.

MATERIAL AND METHODS

Colitis was induced using an enema of trinitrobenzene sulfonic acid (TNBS) and ethanol. Strong Wakamto was administered for 28 days before induction of colitis and for 7 days thereafter, and the effect of this medicine was evaluated.

RESULTS

Treatment with 5% Strong Wakamto improved loss of body-weight, increased colon weight and significantly decreased the histological damage score for colon mucosa. Decreases in faecal Lactobacillus sp., superoxide dismutase activity and zinc concentrations, and the increased IL-1beta expression in colonic tissue after TNBS enema were improved when Strong Wakamto was given. The present in vitro studies indicate that administration of Strong Wakamto prevents lipopolysaccharide-induced TNF-alpha production in human macrophages.

CONCLUSIONS

Oral administration of Strong Wakamto mitigates experimental inflammatory bowel disease induced by TNBS enema in rats. The beneficial effects seem attributable to a combination of balancing microflora, immunomodulatory effects on gut macrophages, and enhancement of anti-superoxide activity in colonic tissues.

Role of interleukin (IL-10) in probiotic-mediated immune modulation: an assessment in wild-type and IL-10 knock-out mice

While the impact of Bifidobacterium infantis 35624 and other probiotics on cytokines has been shown in established colitis, the effects of B. infantis consumption in pre-inflammation of interleukin (IL)-10 knock-out (KO) mice and on the wild-type (WT) C57Bl/6 mice have not been well demonstrated. The objective of this study was to examine cytokine responses in mucosal and systemic lymphoid compartments of IL-10 KO mice early in disease and to compare with control WT mice. Mice were fed B. infantis or placebo for 5 weeks and culled prior to the onset of chronic intestinal inflammation (12-14 weeks). The spleen, Peyer's patches and intestinal mucosa were removed and stimulated with various bacterial stimuli. Cytokine levels were measured by enzyme-linked immunosorbent assay. While basal intestinal and systemic cytokine profiles of WT and IL-10 KO mice were similar, transforming growth factor (TGF)-beta was reduced in the spleen of IL-10 KO mice. Following probiotic consumption, interferon (IFN)-gamma was reduced in the Peyer's patch of both WT and IL-10 KO mice. Alterations in IFN-gamma in the Peyer's patches of WT mice (enhancement) versus IL-10 KO (reduction) were observed following in vitro stimulation with salmonella. Differential IL-12p40, CCL2 and CCL5 responses were also observed in IL-10 KO mice and WT mice. The cytokine profile of IL-10 KO mice in early disease was similar to that of WT mice. The most pronounced changes occurred in the Peyer's patch of IL-10 KO mice, suggesting a probiotic mechanism of action independent of IL-10. This study provides a rationale for the use of B. infantis 35624 for the treatment of gastrointestinal inflammation.

Combination treatment of rat adjuvant-induced arthritis with methotrexate, probiotic bacteria Enterococcus faecium, and selenium

The effects of the probiotic bacteria Enterococcus faecium (EF) and selenium were studied on methotrexate (MTX) treatment in rats with adjuvant arthritis. Arthritic rats were treated orally with the following substances: lyophilized EF (15 mg/kg/day, 5 days a week), sodium selenite pentahydrate (SSe; 0.050 mg/kg containing 0.015 mg/kg selenium, 5 days a week), MTX (0.6 mg/kg/week), and their combinations for the period of 50 days from adjuvant application. Levels of serum albumin, serum nitrite/nitrate concentrations, hind paw swelling, arthrogram scores, whole-body bone mineral density (BMD), and bone erosions were evaluated as markers of inflammation and destructive changes associated with arthritis. Long-term preventive treatment with low-dose MTX significantly inhibited the markers of both inflammation and arthritis. EF or SSe when administered singly or in combination had no significant effect on the given parameters in arthritic rats. EF, but not SSe, potentiated the beneficial effects of MTX, which resulted in a more significant reduction of hind paw swelling, arthrogram scores, and whole-body BMD decrease. EF also had a tendency to improve the effect of MTX on serum albumin and nitrite/nitrate concentrations. Our results indicate that EF may increase the preventive effect of MTX treatment in rat adjuvant arthritis by improving its anti-inflammatory and antiarthritic effects.

Antibiotics and probiotics in treatment of inflammatory bowel disease

Many experimental and clinical observations suggest that intestinal microflora plays a potential role in the pathogenesis of inflammatory bowel disease (IBD). Manipulation of the luminal content using antibiotics or probiotics represents a potentially effective therapeutic option. The available studies do not support the use of antibiotics in ulcerative colitis (UC). Antibiotics are effective in treating septic complications of Crohn’s disease (CD) but their use as a primary therapy is more controversial, although this approach is frequently and successfully adopted in clinical practice.

There is evidence that probiotic therapy may be effective in the prevention and treatment of mild to moderate UC. In contrast, a lack of successful study data at present precludes the widespread use of probiotics in the treatment of CD.

Both antibiotics and probiotics appear to play a beneficial role in the treatment and prevention of pouchitis and further trials are warranted to fully quantify their clinical efficacy.

Environment as a Critical Factor for the Pathogenesis and Outcome of Gastrointestinal Disease: Experimental and Human Inflammatory Bowel Disease and Helicobacter-Induced Gastritis

Environmental factors play an important role in the manifestation, course, and prognosis of diseases of the gastrointestinal tract such as inflammatory bowel disease (IBD) and Helicobacter pylori-induced gastritis. These two disease complexes were chosen for a discussion of the contribution of environmental factors to the disease outcome in humans and animal models. Dissecting complex diseases like IBD and Helicobacter-induced gastritis has shown that the outcome of disease depends on the allelic constellation of a host and the microbial and physical environments. Host alleles predisposing to a disease in one genomic and/or environmental milieu may not be deleterious in other constellations; on the other hand, microbes can have different effects in different hosts and under different environmental conditions. The impact of the complex interaction between host genetics and environmental factors, particularly microflora, also underlines the importance of a defined genetic background and defined environments in animal studies and is indicative of the difficulties in analyzing complex diseases in humans.

Effectiveness of antibiotic combination therapy in patients with active ulcerative colitis: a randomized, controlled pilot trial with long-term follow-up

OBJECTIVE

It is proposed that Fusobacterium varium might be one of the elusive pathogenic factors in ulcerative colitis (UC). Our goal was to assess whether an antibiotic combination therapy against F. varium is effective for induction and maintenance of remission of UC.

MATERIAL AND METHODS

Twenty chronic, active UC patients with F. varium infection were enrolled consecutively and were randomly assigned to receive amoxicillin, tetracycline or metronidazole per os for 2 weeks (treatment group; n=10), or no antibiotics (control group; n=10). F. varium was sensitive to the antibiotics. Symptom assessment, endoscopic and histological evaluations were performed blind before enrollment at 3-5 months and 12-14 months after the treatment. Serum immunoglobulins to F. varium were measured using an enzyme-linked immunosorbent assay (ELISA). Immunohistochemical detection of F. varium in biopsy specimens was carried out using the avidin-biotin complex method.

RESULTS

The clinical activity, endoscopic and histological scores in the treatment group decreased significantly at 3-5 and 12-14 months after the end of treatment compared with those in the control group (p=0.001-0.036). The remission rate in the treatment group was higher than that in the control group (p=0.037). In addition, the titers of antibody to F. varium and the F. varium density in the mucosa decreased at both the short- and long-term follow-ups in the treatment group (p=0.0002-0.049). No serious drug-related toxicity was observed during the trial.

CONCLUSIONS

The 2-week antibiotic combination therapy against F. varium was effective and safe in patients with chronic, active ulcerative colitis in this long-term follow-up study.

Diminished cytokine signalling against bacterial components in mononuclear leucocytes from ulcerative colitis patients after leukocytapheresis

Infiltration by circulating inflammatory cells is a prominent local inflammatory feature of ulcerative colitis (UC). Several trials have suggested that leukocytapheresis by filtration can benefit patients with active UC. We investigated how this therapy might modulate the inflammatory response. Patients with active UC who were beginning repeated filtration leukocytapheresis were studied. Mononuclear cell preparations were obtained from blood before and after the first treatment, and expression of cytokine signalling components and the cell-proliferative response were analysed in vitro. Leukocytapheresis reduced lipopolysaccharide-induced production of proinflammatory cytokines (interleukin-1, -6, -8 and tumour necrosis factor-alpha, P < 0.05 for all) and activation of intracellular signalling components (nuclear factor-kappaB, mitogen-activated protein kinases, and signal transducer and activator of transcription-3), as well as surface expression of toll-like receptor-4 (P < 0.05) in mononuclear cells. The therapy also reduced the cell-proliferative response by mononuclear cells stimulated with sonicated bacterial preparations from autologous intestine (P < 0.05). These results indicate that activated mononuclear cells in the peripheral blood of patients with active UC are removed by leukocytapheresis and replaced by cells with a lower activation status. This replacement may partly explain the therapeutic benefit.

The role of Toll-like receptor 4 Asp299Gly and Thr399Ile polymorphisms and CARD15/NOD2 mutations in the susceptibility and phenotype of Crohn's disease

BACKGROUND

We investigated the influence of 2 common Toll-like receptor 4 (TLR4) polymorphisms on susceptibility and disease characteristics of Crohn's disease (CD).

METHODS

Genomic DNA from 204 patients with CD and 199 unrelated controls was analyzed for the presence of 2 single nucleotide polymorphisms in the TLR4 gene, resulting in the amino acid substitutions Asp299Gly and Thr399Ile. In addition, the carrier status for the 3 common CD-associated CARD15/NOD2 gene mutations, Arg702Trp, Gly908Arg, and 1007fs, was determined. The frequency of the different genotypes was compared, and a detailed genotype-phenotype correlation was performed.

RESULTS

An almost 2-fold increase in the frequency of the TLR4 Asp299Gly phenotype was observed in patients with CD (14.2%) compared with healthy controls (7.5%, P = 0.038, odds ratio = 2.03). The prevalence of a stricturing phenotype was increased in patients heterozygous for 1 of the TLR4 polymorphisms studied (Asp299Gly, 34.5%; Thr399Ile, 36.7%) compared with patients with wild-type TLR4 (17.1% and 16.7%; P = 0.04 and 0.02, respectively). The presence of the Asp299Gly polymorphism in the absence of CARD15/NOD2 mutations was a particularly strong predictor of the stricturing disease phenotype that was present in 47.4% of the patients with Asp299Gly+/NOD2- compared with 10.1% of the patients with the Asp299Gly-/NOD2+ status (P = 0.0009; P = 0.0004 for Thr399Ile+/NOD2- versus Thr399Ile-/NOD2+). In contrast, there was a trend toward a higher prevalence of the penetrating phenotype in the TLR4-/NOD2+ group (71.6%) compared with the TLR4+/NOD2- group (47.4%, P = 0.059).

CONCLUSIONS

The TLR4 Asp299Gly polymorphism is a risk factor for CD. TLR4 and CARD15/NOD2 mutations may contribute to distinct disease phenotypes.

Current concept of pathophysiological understanding and natural course of ulcerative colitis

INTRODUCTION

According to the current paradigm both ulcerative colitis (UC) and Crohn's disease (CD) result from a complex interplay of genetic susceptibility factors, environmental factors, alterations of the physiological intestinal flora and a defective regulation of the intestinal immune system.

DISCUSSION

The objective of this review is to give an overview of these factors and mechanisms, including genetic, environmental and microbial factors, with special alterations of relevant cellular components of the intestinal immune system such as T cells, macrophages and epithelial cells will then be addressed. In addition, the most relevant animal model systems that have contributed to our current pathogenetic understanding will be introduced. Clinically, the natural course of UC with special reference to the risk of colorectal cancer will be addressed.

CONCLUSION

The elucidation of pathomechanisms at the level of the intestinal immune system provides the potential for novel, effective treatment strategies. Best surgical management of patients with UC, however, still remains a challenge.

Contrasting activity of cytosin-guanosin dinucleotide oligonucleotides in mice with experimental colitis

Intestinal inflammation in inflammatory bowel disease (IBD) and experimental models of colitis is characterized by a dysregulated intestinal immune response with elevated levels of Th1 cytokines. The luminal flora has been implicated as a major factor contributing to the initiation and perpetuation of inflammation in experimental colitis by mechanisms not known. Bacterial DNA contains unmethylated cytosin-guanosin dinucleotides (CpG) which strongly activate Th1-mediated immune responses. To test whether these CpG-motifs modulate intestinal inflammation we treated mice with dextran sulphate sodium (DSS)-induced colitis with CpG-containing oligodeoxynucleotides (CpG-ODN). CpG-ODN given after the onset of DSS colitis aggravated the disease, as indicated by a significantly increased loss of body weight and a 30% increase of the histological score. Further, we found a severe increase of proinflammatory cytokines (interleukin (IL)-6: 40-fold; interferon (IFN)-gamma: 11-fold). In a pretreatment setting CpG-ODN reduced weight loss significantly and reduced intestinal inflammation by 45%. Colonic IFN-gamma and IL-6 mRNA levels were reduced by 75%, and IL-10 was elevated by 400% compared to controls. The prophylactic CpG-effect was not imitated by IL-12 because IL-12 pretreatment was not protective. In time-course experiments, CpG-ODN pretreatment over 5 days resulted in a tolerance effect concerning its IFN-gamma-inducing quality, and during the following days of colitis induction IL-10 secretion from mesenterial lymph node cells was elevated compared to controls. Therefore, the prophylactic effect of CpG-ODN might be explained by its tolerizing effect and/or the increased ability for IL-10 production during the consecutive intestinal inflammation.

Membrane peroxidation by lipopolysaccharide and iron-ascorbate adversely affects Caco-2 cell function: beneficial role of butyric acid

BACKGROUND

Membrane lipid peroxidation may play a role in immune-mediated bowel diseases.

OBJECTIVE

We examined the effects of lipopolysaccharide (LPS), a ubiquitous endotoxin mediator of gram-negative bacteria, alone and in combination with iron-ascorbate, on enterocyte function. Furthermore, we assessed the antioxidant capacity of butylated hydroxytoluene (BHT) and butyric acid, which are known to play a significant role in the welfare of intestinal mucosa.

DESIGN

Differentiated intestinal Caco-2 cells were used to study the induction of membrane peroxidation by LPS (100 micro g/mL) and iron-ascorbate (0.2 and 2 mmol/L, respectively) and to examine the beneficial effects of BHT and butyric acid.

RESULTS

A significant dose-dependent increase in malondialdehyde, accompanied by lower apical membrane fluidity and significantly decreased sucrase activity, was observed when Caco-2 cells were incubated with LPS. LPS also augmented paracellular permeability ([(14)C]polyethylene glycol flux), prostaglandin E(2) production, and cyclooxygenase-2 (EC 1.14.99.1) expression. These abnormalities were exacerbated by the coadministration of iron-ascorbate, but most of them were suppressed by butyric acid and BHT.

CONCLUSION

Bacterial endotoxin and prooxidants may overwhelm antioxidant defenses and become deleterious to enterocyte function, whereas butyric acid and BHT may provide antioxidant protection.

Ca2+ response in neutrophils after exposure to bacterial N-formyl-methionyl-leucyl-phenylalanine: delayed response in ulcerative colitis

OBJECTIVE

In acute stages of ulcerative colitis (UC), neutrophils migrate from the circulation into inflamed colonic tissue, initiated by yet unknown stimuli. The bacterial peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) is a component of the surface membrane of colonic bacteria such as Escherichia coli and stimulates Ca2+ influx into neutrophils, reflecting the fact that ionized calcium is an important secondary messenger for several neutrophil functions, including locomotion, phagocytosis and free oxygen radical production. Recent studies have revealed that Ca2+ dependent ICAM-1/beta 2-integrin mediated neutrophil migration is impaired in UC patients. The aim of the present work was to study the influx of Ca2+ into peripheral blood neutrophils of UC patients after exposure to FMLP and after binding of either beta 2-integrins or intercellular adhesion molecule-1 (ICAM-1).

METHODS

The relative intracellular Ca2+ levels ([Ca2+]i ) were measured spectrofluorometrically in neutrophils isolated from eight UC patients and eight controls. The cells were exposed to 1 nm FMLP, 5 pm free ICAM-1, or antibodies binding ICAM-1 or the beta 2-integrins CD11a, CD11b, CD11c and CD18.

RESULTS

A pronounced increase in [Ca2+]i was observed by exposure of cells to FMLP, and neutrophils from UC patients showed a consistent and significant delayed response as compared to cells from control subjects (P < 0.01). Antibody mediated cross-linking of CD18 triggered a small but detectable increase in [Ca2+]i, which did not differ between patients and controls.

CONCLUSION

A delayed response to bacterial peptides appears to be a phenotypic trait for neutrophils of UC patients. A connection between FMLP stimulated Ca2+ influx and CD11/CD18 upregulation is discussed.

Probiotics and intestinal health effects: a clinical perspective

Probiotics are viable non-pathogenic micro-organisms which, when ingested, exert a positive influence on host health or physiology. We have critically analysed the evidence for the efficacy of specific probiotic strains in human gastrointestinal diseases. The best evidence can be obtained with randomised controlled trials which avoid bias. Good evidence has been obtained with several strains in the prevention or treatment of antibiotic-associated disorders, in the treatment (and to a lesser extent prevention) of gastroenteritis and acute diarrhoea and in the alleviation of lactose intolerance. We also analysed the recent randomised controlled trials performed in patients with Clostridium difficile or Helicobacter pylori, inflammatory bowel disease, irritable bowel syndrome, non-ulcer dyspepsia and colon cancer.

Role of mucins in inflammatory bowel disease: important lessons from experimental models

Inflammatory bowel disease (IBD) is characterized by a chronically inflamed mucosa of the gastrointestinal tract, caused by an underlying immune imbalance and triggered by luminal substances, including bacteria. Mucus forms a gel layer covering the gastrointestinal tract, acting as a semi-permeable barrier between the lumen and the epithelium. Mucins, the building blocks of the mucus gel, determine the thickness and properties of mucus. In IBD in humans, alterations in both membrane-bound and secretory mucins have been described involving genetic mutations in mucin genes, changes in mucin mRNA and protein levels, degree of glycosylation, sulphation, and degradation of mucins. As mucins are strategically positioned between the vulnerable mucosa and the bacterial contents of the bowel, changes in mucin structure and/or quantity probably influence their protective functions and therefore constitute possible aetiological factors in the pathogenesis of IBD. This hypothesis, however, is difficult to prove in humans. Animal models for IBD permit detailed analysis of those aspects of mucins necessary for protection against disease. These models revealed pertinent data as for how changes in mucins, in particular in MUC2, imposed by immunological or microbial factors, may contribute to the development and/or perpetuation of chronic IBD, and shed some light on possible strategies to counteract disease.

Treatment of distal colitis with local anaesthetic agents

The results of clinical and experimental studies on topical treatment of distal colitis with local anaesthetic agents are summarized. The original observation was an adrenergic hyperinnervation of the inflamed mucosa (hyperinnervation hypothesis). In order to silence local nervous reflexes, the mucosa was treated topically with 2% lidocaine gel. The clinical results are promising and no side effects have been observed. The relapse rate is relatively high and related to the duration of treatment. In studies of experimental colitis a potential antagonism between harmful adrenergic nerves (vasoconstrictor substances and proinflammatory cytokines) and mucosa-protective visceral afferents (antiinflammatory cytokines) in the pathogenesis of colitis is intriguing. Other studies have emphasized the importance of neutrophils for causing damage to the colon epithelium (neutrophil hypothesis) and local anaesthetics have potent effects on several steps of the inflammatory response in addition to the nervous blockade.

Association between anal furunculosis and colitis in the dog: preliminary observations

Treatment of anal furunculosis in dogs is often unsatisfactory and may be associated with significant recurrence and complications. This may be compounded by the simultaneous presence of colitis in affected animals. Clinical signs associated with colitis and anal furunculosis may be similar, including faecal tenesmus, dyschezia and haematochezia. To examine the incidence of concurrent anal furunculosis and colitis, colonic biopsies were collected from 18 dogs referred for treatment of anal furunculosis. Nine dogs (50 per cent) had a histopathological diagnosis of colitis. Clinical signs more indicative of colitis than anal furunculosis (increased frequency of defecation, mucus in faeces and diarrhoea) were not observed more frequently in dogs with confirmed colitis compared with those with furunculosis alone. Therefore, while an association between colitis and anal furunculosis may exist, clinical signs alone cannot be used as an indicator of the presence of colitis in cases of anal furunculosis. The authors recommend that colonic biopsies should be undertaken in all dogs presented with anal furunculosis. Whether specific treatment of colitis in dogs with histopathological evidence of colitis improves the outcome of treatment for anal furunculosis awaits further study.

Helicobacter bilis infection accelerates and H. hepaticus infection delays the development of colitis in multiple drug resistance-deficient (mdr1a-/-) mice

mdr1a-deficient mice lack P-glycoprotein and spontaneously develop colitis with age. Helicobacter spp. are gram-negative organisms that have been associated with colitis in certain mouse strains, but Helicobacter spp. have been excluded as contributing to the spontaneous colitis that develops in mdr1a-/- mice. We wished to determine whether infection with either H. bilis or H. hepaticus would accelerate the development of inflammatory bowel disease (IBD) in mdr1a-/- mice. We found that H. bilis infection induced diarrhea, weight loss, and IBD in mdr1a-/- mice within 6 to 17 weeks post-inoculation and before the expected onset of spontaneous IBD. Histopathology of H. bilis-induced IBD included crypt hyperplasia, inflammatory cell infiltrates, crypt abscesses, and obliteration of normal gut architecture. Reverse transcription-polymerase chain reaction and Taqman analysis from colonic tissue showed increased transcripts for interferon-gamma and interleukin-10 from H. bilis-infected colitic mdr1a-/- mice. Additionally, mesenteric lymph nodes had increased cellularity with expansion of CD4+ and CD8+ T cells and B cells and increased proliferation to soluble H. bilis antigens with elaboration of interferon-gamma, tumor necrosis factor-alpha and interleukin-10. In contrast, H. hepaticus infection of mdr1a-/- mice did not accelerate disease but rather delayed the onset of spontaneous colitis which was milder in severity. mdr1a-/- mice infected with Helicobacter spp. may provide a useful tool to explore the pathogenesis of microbial-induced IBD in a model with a presumed epithelial cell "barrier" defect.

Clinical aspects and pathophysiology of inflammatory bowel disease

The chronic inflammatory bowel diseases (IBD), Crohn's disease and ulcerative colitis, are recognized as important causes of gastrointestinal disease in children and adults. In this review we delineate the clinical manifestations and diagnostic features of IBD. In addition, we summarize important recent advances in our understanding of the immune mediators of intestinal inflammation. This information has led to new therapeutic approaches in IBD. Further, we discuss the considerable data that point to the significance of genetic factors in the development of IBD and the genetic loci which have been implicated through genome-wide searches. The commensal bacterial flora also appears to be a critical element, particularly in regards to Crohn's disease, although the precise role of the bacteria in the disease manifestations remains unclear. Current investigations promise to yield fresh insights in these areas.

Enzyme degradation and proinflammatory activity in arthritogenic and nonarthritogenic Eubacterium aerofaciens cell walls

Two almost-identical strains of Eubacterium aerofaciens isolated from the normal human gut flora were used. The cell wall (CW) of one strain with a peptidoglycan (PG) type A4alpha induces chronic arthritis in the rat after a single intraperitoneal injection, whereas CW of the other with PG type A4beta induces only a transient acute arthritis. The CW of the arthritogenic E. aerofaciens was a twofold-more-potent stimulator of the proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and monocyte chemoattractant protein 1 (MCP-1) than the nonarthritogenic CW. After degradation with mutanolysin, the capacity of the arthritogenic PG to stimulate production of TNF-alpha and MCP-1 was significantly increased, whereas that of the nonarthritogenic PG was significantly decreased. In other words, after enzyme degradation the arthritogenic PG had a four- to fivefold-stronger stimulatory capacity than that of the enzyme-treated nonarthritogenic PG. These findings indicate that the arthritogenicity of CW or a PG is not dependent on the enzyme resistance alone but also on how the PG fragments released by enzyme degradation stimulate the production of proinflammatory cytokines.

Differential alteration in intestinal epithelial cell expression of toll-like receptor 3 (TLR3) and TLR4 in inflammatory bowel disease

Initiation and perpetuation of the inflammatory intestinal responses in inflammatory bowel disease (IBD) may result from an exaggerated host defense reaction of the intestinal epithelium to endogenous lumenal bacterial flora. Intestinal epithelial cell lines constitutively express several functional Toll-like receptors (TLRs) which appear to be key regulators of the innate response system. The aim of this study was to characterize the expression pattern of TLR2, TLR3, TLR4, and TLR5 in primary intestinal epithelial cells from patients with IBD. Small intestinal and colonic biopsy specimens were collected from patients with IBD (Crohn's disease [CD], ulcerative colitis [UC]) and controls. Non-IBD specimens were assessed by immunofluorescence histochemistry using polyclonal antibodies specific for TLR2, TLR3, TLR4, and TLR5. Primary intestinal epithelial cells (IEC) of normal mucosa constitutively expressed TLR3 and TLR5, while TLR2 and TLR4 were only barely detectable. In active IBD, the expression of TLR3 and TLR4 was differentially modulated in the intestinal epithelium. TLR3 was significantly downregulated in IEC in active CD but not in UC. In contrast, TLR4 was strongly upregulated in both UC and CD. TLR2 and TLR5 expression remained unchanged in IBD. These data suggest that IBD may be associated with distinctive changes in selective TLR expression in the intestinal epithelium, implying that alterations in the innate response system may contribute to the pathogenesis of these disorders.

Interleukin 10-deficient colitis: new similarities to human inflammatory bowel disease

BACKGROUND

Interleukin (IL) 10 is a potent anti-inflammatory cytokine. Disruption of the IL-10 gene in C57/Black6 mice results in enterocolitis in the presence of intestinal bacteria. This study investigated gut mucosal barrier function sequentially during the development of colitis in this model.

METHODS

Animals were bred in specific pathogen-free conditions and transferred to conventional housing at 4 weeks. Mice were evaluated at 6, 8, 10, 12, 14 and 15 weeks of age. Barrier function was assessed by measuring intestinal permeability and antibody response to systemic endotoxaemia (antibody to the core glycolipid region of lipopolysaccharide; EndoCAb). Colons were harvested and a histological injury score (HIS) was calculated.

RESULTS

The HIS increased progressively until 12 weeks, with an associated increase in intestinal permeability, and immunoglobulin (Ig) M and IgG EndoCAb. The HIS correlated positively with both intestinal permeability and IgM and IgG EndoCAb. Intestinal permeability showed a positive correlation with EndoCAb.

CONCLUSION

IL-10 knockout mice develop colitis with an associated disturbance in gut mucosal barrier function, as measured by increased permeability and endotoxaemia. The colitis found in the IL-10 knockout mouse shares these histological, physiological and biochemical features with human inflammatory bowel disease and is therefore suitable for therapeutic trials. A measure of endotoxaemia correlated directly with intestinal permeability in this model.

Improved growth and viability of lactobacilli in the presence of Bacillus subtilis (natto), catalase, or subtilisin

In an effort to demonstrate the potential usefulness of Bacillus subtilis (natto) as a probiotic, we examined the effect of this organism on the growth of three strains of lactobacilli co-cultured aerobically in vitro. Addition of B. subtilis (natto) to the culture medium resulted in an increase in the number of viable cells of all lactobacilli tested. Since B. subtilis (natto) can produce catalase, which has been reported to exhibit a similar growth-promoting effect on lactobacilli, we also examined the effect of bovine catalase on the growth of Lactobacillus reuteri JCM 1112 and L. acidophilus JCM 1132. Both catalase and B. subtilis (natto) enhanced the growth of L. reuteri JCM 1112, whereas B. subtilis (natto) but not catalase enhanced the growth of L. acidophilus JCM 1132. In a medium containing 0.1 mM hydrogen peroxide, its toxic effect on L. reuteri JCM 1112 was abolished by catalase or B. subtilis (natto). In addition, a serine protease from B. licheniformis, subtilisin, improved the growth and viability of L. reuteri JCM 1112 and L. acidophilus JCM 1132 in the absence of hydrogen peroxide. These results indicate that B. subtilis (natto) enhances the growth and (or) viability of lactobacilli, possibly through production of catalase and subtilisin.

Exploitation of host cells by enteropathogenic Escherichia coli

Microbial pathogens have evolved many ingenious ways to infect their hosts and cause disease, including the subversion and exploitation of target host cells. One such subversive microbe is enteropathogenic Escherichia coli (EPEC). A major cause of infantile diarrhea in developing countries, EPEC poses a significant health threat to children worldwide. Central to EPEC-mediated disease is its colonization of the intestinal epithelium. After initial adherence, EPEC causes the localized effacement of microvilli and intimately attaches to the host cell surface, forming characteristic attaching and effacing (A/E) lesions. Considered the prototype for a family of A/E lesion-causing bacteria, recent in vitro studies of EPEC have revolutionized our understanding of how these pathogens infect their hosts and cause disease. Intimate attachment requires the type III-mediated secretion of bacterial proteins, several of which are translocated directly into the infected cell, including the bacteria's own receptor (Tir). Binding to this membrane-bound, pathogen-derived protein permits EPEC to intimately attach to mammalian cells. The translocated EPEC proteins also activate signaling pathways within the underlying cell, causing the reorganization of the host actin cytoskeleton and the formation of pedestal-like structures beneath the adherent bacteria. This review explores what is known about EPEC's subversion of mammalian cell functions and how this knowledge has provided novel insights into bacterial pathogenesis and microbe-host interactions. Future studies of A/E pathogens in animal models should provide further insights into how EPEC exploits not only epithelial cells but other host cells, including those of the immune system, to cause diarrheal disease.

Promotion of a favorable gut flora in inflammatory bowel disease

Recent evidence suggests that the composition of colonic flora plays a role in intestinal inflammation in inflammatory bowel disease (IBO). This review examines the evidence that altering the concentrations of colonic bacteria might benefit patients with this condition.

What determines arthritogenicity of bacterial cell wall? A study on Eubacterium cell wall-induced arthritis

OBJECTIVE

To study what determines the arthritogenicity of the bacterial cell wall (CW) using Eubacterium CW-induced arthritis in the rat.

METHODS

Eubacterium aerofaciens, previously reported as arthritogenic, and E. limosum and E. alactolyticum, known as non-arthritogenic, were used. Gas chromatography-mass spectrometry (GC-MS) was applied to analyse the chemical composition of the bacterial cell wall. Cellular immune response was measured by concanavalin A (Con A) stimulation and FACScan analysis. Also, serum antibodies against the injected cell wall were determined.

RESULTS

Unexpectedly, from the two strains of E. aerofaciens used only one proved to be arthritogenic (with a CW inducing chronic arthritis after a single intraperitoneal injection), even though these two strains were 100% identical by 16S rDNA analysis. CW of the other E. aerofaciens strain induced only transient acute arthritis; CW of E. limosum and E. alactolyticum induced weak signs of acute arthritis. Based on the GC-MS analysis and on the results published previously, putative structures of peptidoglycan (PG) in the four CW preparations are presented. It is apparent that the presence of lysine in position 3 of the PG stem peptide contributes to arthritogenicity but is alone not decisive. Both strains of E. aerofaciens were immunosuppressive, when tested by Con A response at 2 weeks after CW injection. Such an immunosuppression was not observed after injection of CW from E. limosum or E. alactolyticum. FACScan analysis for six T cell markers and studies on serum antibody responses did not reveal any differences in the effect of the four bacterial strains used.

CONCLUSIONS

The results obtained suggest that the chemical structure of PG present in the bacterial CW is decisive in determining arthritogenicity/non-arthritogenicity. Therefore, from two bacterial strains belonging to normal human intestinal flora and 100% identical by 16S rDNA analysis, one proved to be arthritogenic and the other non-arthritogenic.