Serum tryptophan metabolites are associated with erosive hand osteoarthritis and pain: results from the DIGICOD cohort.

OBJECTIVE: To investigate host and gut-microbiota related Tryptophan metabolism in hand osteoarthritis (HOA). METHODS: The baseline serum concentration of 20 Tryptophan metabolites was measured in 416 HOA patients in a cross-sectional analysis of the DIGICOD cohort. Tryptophan metabolites levels, metabolite-ratios and metabolism pathway activation were compared between erosive (N = 141) and non-erosive HOA (N = 275) by multiple logistic regressions adjusted on age, BMI and sex. The association between Tryptophan metabolite levels and HOA symptoms was investigated by a Spearman's rank correlation analysis. RESULTS: Four serum Tryptophan metabolites, eight metabolite ratios and one metabolism pathway were associated with erosive HOA. Erosive HOA was negatively associated with Tryptophan (odds ratio (OR) = 0.41, 95% confidence interval [0.24-0.70]), indole-3-aldehyde (OR = 0.67 [0.51-0.90]) and 3-OH-anthranilic acid (OR = 1.32 [1.13-1.54]) and positively with 5-OH-Tryptophan levels (OR = 1.41 [1.13-1.77]). The pro-inflammatory kynurenine-indoleamine 2,3-dioxygenase pathway was upregulated in erosive HOA (OR = 1.60 [1.11-2.29]). Eleven metabolites were correlated with HOA symptoms and were mostly pain-related. Serotonin and N-acetyl serotonin levels were negatively correlated with number of tender joints. Indole-3-aldehyde level was negatively correlated and 3-OH-anthranilic acid, 3-OH-kynurenine and 5-OH-Tryptophan levels were positively correlated with number of patients-reported painful joints. Quinolinic acid and 3-OH-kynurenine levels correlated positively with AUSCAN pain. CONCLUSIONS: Tryptophan metabolites disturbance is associated with erosive HOA and pain and emphasize the role of low-grade inflammation and gut dysbiosis in HOA.

Identification of an anti-inflammatory protein from Faecalibacterium prausnitzii, a commensal bacterium deficient in Crohn's disease.

BACKGROUND: Crohn's disease (CD)-associated dysbiosis is characterised by a loss of Faecalibacterium prausnitzii, whose culture supernatant exerts an anti-inflammatory effect both in vitro and in vivo. However, the chemical nature of the anti-inflammatory compounds has not yet been determined. METHODS: Peptidomic analysis using mass spectrometry was applied to F. prausnitzii supernatant. Anti-inflammatory effects of identified peptides were tested in vitro directly on intestinal epithelial cell lines and on cell lines transfected with a plasmid construction coding for the candidate protein encompassing these peptides. In vivo, the cDNA of the candidate protein was delivered to the gut by recombinant lactic acid bacteria to prevent dinitrobenzene sulfonic acid (DNBS)-colitis in mice. RESULTS: The seven peptides, identified in the F. prausnitzii culture supernatants, derived from a single microbial anti-inflammatory molecule (MAM), a protein of 15 kDa, and comprising 53% of non-polar residues. This last feature prevented the direct characterisation of the putative anti-inflammatory activity of MAM-derived peptides. Transfection of MAM cDNA in epithelial cells led to a significant decrease in the activation of the nuclear factor (NF)-κB pathway with a dose-dependent effect. Finally, the use of a food-grade bacterium, Lactococcus lactis, delivering a plasmid encoding MAM was able to alleviate DNBS-induced colitis in mice. CONCLUSIONS: A 15 kDa protein with anti-inflammatory properties is produced by F. prausnitzii, a commensal bacterium involved in CD pathogenesis. This protein is able to inhibit the NF-κB pathway in intestinal epithelial cells and to prevent colitis in an animal model.

Decreased tryptophan and increased kynurenine levels in mastocytosis associated with digestive symptoms.

The main metabolism pathway of tryptophan is protein formation, but it can also be metabolized into serotonin and kynurenine. Indoleamine 2,3-dioxygenase (IDO) is the enzyme that catalyzes the degradation of tryptophan into kynurenine. Mastocytosis is a heterogeneous disease characterized by mast cell accumulation in various tissues with 57% of patients having gastrointestinal involvement. We studied tryptophan metabolism in mastocytosis patients displaying or not gastrointestinal features and healthy subjects (n = 26 in each group). Mastocytosis patients with digestive symptoms displayed significantly increased kynurenine level and IDO activity as compared to healthy controls and mastocytosis patients without digestive symptoms. This could be linked to mast cell-mediated digestive inflammation among patients with mastocytosis. This work is the first focusing on kynurenine pathway in a mast cell disease and could help to understand the pathogenesis of digestive features in mastocytosis as well as in other mast cell-mediated diseases.

Dissecting the respective roles of microbiota and host genetics in the susceptibility of Card9-/- mice to colitis.

BACKGROUND: The etiology of inflammatory bowel disease (IBD) is unclear but involves both genetics and environmental factors, including the gut microbiota. Indeed, exacerbated activation of the gastrointestinal immune system toward the gut microbiota occurs in genetically susceptible hosts and under the influence of the environment. For instance, a majority of IBD susceptibility loci lie within genes involved in immune responses, such as caspase recruitment domain member 9 (Card9). However, the relative impacts of genotype versus microbiota on colitis susceptibility in the context of CARD9 deficiency remain unknown. RESULTS: Card9 gene directly contributes to recovery from dextran sodium sulfate (DSS)-induced colitis by inducing the colonic expression of the cytokine IL-22 and the antimicrobial peptides Reg3ß and Reg3γ independently of the microbiota. On the other hand, Card9 is required for regulating the microbiota capacity to produce AhR ligands, which leads to the production of IL-22 in the colon, promoting recovery after colitis. In addition, cross-fostering experiments showed that 5 weeks after weaning, the microbiota transmitted from the nursing mother before weaning had a stronger impact on the tryptophan metabolism of the pups than the pups' own genotype. CONCLUSIONS: These results show the role of CARD9 and its effector IL-22 in mediating recovery from DSS-induced colitis in both microbiota-independent and microbiota-dependent manners. Card9 genotype modulates the microbiota metabolic capacity to produce AhR ligands, but this effect can be overridden by the implantation of a WT or "healthy" microbiota before weaning. It highlights the importance of the weaning reaction occurring between the immune system and microbiota for host metabolism and immune functions throughout life. A better understanding of the impact of genetics on microbiota metabolism is key to developing efficient therapeutic strategies for patients suffering from complex inflammatory disorders. Video Abstract.

Gut barrier-microbiota imbalances in early life lead to higher sensitivity to inflammation in a murine model of C-section delivery.

BACKGROUND: Most interactions between the host and its microbiota occur at the gut barrier, and primary colonizers are essential in the gut barrier maturation in the early life. The mother-offspring transmission of microorganisms is the most important factor influencing microbial colonization in mammals, and C-section delivery (CSD) is an important disruptive factor of this transfer. Recently, the deregulation of symbiotic host-microbe interactions in early life has been shown to alter the maturation of the immune system, predisposing the host to gut barrier dysfunction and inflammation. The main goal of this study is to decipher the role of the early-life gut microbiota-barrier alterations and its links with later-life risks of intestinal inflammation in a murine model of CSD. RESULTS: The higher sensitivity to chemically induced inflammation in CSD mice is related to excessive exposure to a too diverse microbiota too early in life. This early microbial stimulus has short-term consequences on the host homeostasis. It switches the pup's immune response to an inflammatory context and alters the epithelium structure and the mucus-producing cells, disrupting gut homeostasis. This presence of a too diverse microbiota in the very early life involves a disproportionate short-chain fatty acids ratio and an excessive antigen exposure across the vulnerable gut barrier in the first days of life, before the gut closure. Besides, as shown by microbiota transfer experiments, the microbiota is causal in the high sensitivity of CSD mice to chemical-induced colitis and in most of the phenotypical parameters found altered in early life. Finally, supplementation with lactobacilli, the main bacterial group impacted by CSD in mice, reverts the higher sensitivity to inflammation in ex-germ-free mice colonized by CSD pups' microbiota. CONCLUSIONS: Early-life gut microbiota-host crosstalk alterations related to CSD could be the linchpin behind the phenotypic effects that lead to increased susceptibility to an induced inflammation later in life in mice. Video Abstract.

Unilateral carotid granulomatous arteritis and Crohn's disease.

Chronic idiopathic granulomatous arteritis of the large vessels - and, specifically, "Takayasu's arteritis" and "giant cell arteritis" - is an unusual condition that rarely leads to stroke and is only occasionally associated with Crohn's disease. We report here on a unique case of a 56-year-old man with a 25-year history of Crohn's disease who also had a 4-year history of recurrent right-sided ischaemic strokes and partial seizures, and a unilateral progressive retrograde occlusion of the right internal and common carotid arteries. Biopsies of the temporal and carotid arteries showed large-vessel granulomatous arteritis, with features of both giant cell and Takayasu's arteritis.

Inflammatory bowel disease and lymphoproliferative disorders: the dust is starting to settle.

The risk of lymphoproliferative disorders (LDs) has become a major concern for clinicians managing patients with inflammatory bowel disease (IBD). Yet it is difficult to distinguish the possible responsibility of immunosuppressive therapy from the background risk due to the inflammatory disorder itself. LDs are clonal B or T cell proliferation showing considerable heterogeneity and the incidence has increased since the 1970s. The strongest and best-established risk factors for LDs are primary and acquired immunodeficiency (HIV, immunosuppressant), notably via defective immune surveillance of Epstein-Barr virus. In many auto-immune diseases (eg, Sjögren's syndrome), inflammatory diseases (eg, rheumatoid arthritis) or chronic suppuration (chronic pyothorax), the risk of LD is increased. In IBD patients, in general, the risk of LD seems to be similar to or very slightly higher than in the general population. The role of immunosuppressants in lymphomagenesis is difficult to individualise because other factors potentially involved are inter-linked. Concordant data suggest that thiopurine therapy is associated with a moderately increased risk of LD. Data regarding methotrexate are scarce and come from diseases other than IBD but the risk seems low. Data regarding risk of LD in IBD patients receiving anti-tumour necrosis factor alpha (TNFalpha) agents are insufficient at this time, mainly because most of the patients are co-treated with thiopurines. The recently individualised risks of hepatosplenic T cell lymphoma and fatal post-mononucleosis LD, in young male patients with IBD who are co-treated with anti-TNFalpha and thiopurines, and EBV-seronegative IBD males, respectively, are probably low but remain to be better quantified.

Plexitis as a predictive factor of early postoperative clinical recurrence in Crohn's disease.

BACKGROUND AND AIMS: A previous study suggested that the presence of myenteric plexitis in the proximal resection margins could be predictive of early endoscopic recurrence after ileocolonic or ileal resection for Crohn's disease (CD). The aim of the present study was to assess the predictive value of plexitis for early clinical CD recurrence. METHODS: All consecutive patients with ileocolonic or ileal resection for active CD in Lariboisière Hospital (Paris) between 1995 and 2006 were included. Clinical, surgical, histological and follow-up data were extracted from medical charts. Early clinical recurrence was defined as the reappearance of CD clinical manifestations requiring a specific treatment within 2 years postsurgery. The proximal resection margin was analysed using haematein eosin saffron (HES) staining and immunochemistry targeting mastocytes (anti-CD117 antibody) and lymphocytes (anti-CD3 antibody). Eosinophils were detected by HES staining. Ten cases of ileocolonic resections for caecal carcinoma served as controls. RESULTS: Data were available from 171 postoperative follow-up periods in 164 patients with CD. Early clinical recurrence of CD occurred in 28.1%. In multivariate analysis, factors associated with postoperative recurrence were active smoking (hazard ratio (HR) = 1.94; 95% CI 1.06 to 3.60; p = 0.033), submucosal plexitis with >or=3 mastocytes (HR = 1.87; 95% CI 1.00 to 3.46; p = 0.048) and a disease-free resection margin <5 cm (HR = 0.52; 95% CI 0.27 to 1.02; p = 0.059). CONCLUSIONS: Submucosal plexitis is associated with early clinical recurrence and could be taken into account in studies searching for new treatment strategies in the immediate postoperative period.

Toll-like receptor 2 is critical for induction of Reg3 beta expression and intestinal clearance of Yersinia pseudotuberculosis.

OBJECTIVE: Yersinia pseudotuberculosis causes ileitis and mesenteric lymphadenitis by mainly invading the Peyer's patches that are positioned in the terminal ileum. Whereas toll-like-receptor 2 (TLR2) controls mucosal inflammation by detecting certain microbiota-derived signals, its exact role in protecting Peyer's patches against bacterial invasion has not been defined. DESIGN: Wild-type, Tlr2-, Nod2- and MyD88-deficient animals were challenged by Y pseudotuberculosis via the oral or systemic route. The role of microbiota in conditioning Peyer's patches against Yersinia through TLR2 was assessed by delivering, ad libitum, exogenous TLR2 agonists in drinking water to germ-free and streptomycin-treated animals. Bacterial eradication from Peyer's patches was measured by using a colony-forming unit assay. Expression of cryptdins and the c-type lectin Reg3 beta was quantified by quantitative reverse transcriptase polymerase chain reaction analysis. RESULTS: Our data demonstrated that Tlr2-deficient mice failed to limit Yersinia dissemination from the Peyer's patches and succumbed to sepsis independently of nucleotide-binding and oligomerisation domain 2 (NOD2). Recognition of both microbiota-derived and myeloid differentiation factor 88 (MyD88)-mediated elicitors was found to be critically involved in gut protection against Yersinia-induced lethality, while TLR2 was dispensable to systemic Yersinia infection. Gene expression analyses revealed that optimal epithelial transcript level of the anti-infective Reg3 beta requires TLR2 activation. Consistently, Yersinia infection triggered TLR2-dependent Reg3 beta expression in Peyer's patches. Importantly, oral treatment with exogenous TLR2 agonists in germ-free animals was able to further enhance Yersinia-induced expression of Reg3 beta and to restore intestinal resistance to Yersinia. Lastly, genetic ablation of Reg3 beta resulted in impaired clearance of the bacterial load in Peyer's patches. CONCLUSIONS: TLR2/REG3 beta is thus an essential component in conditioning epithelial defence signalling pathways against bacterial invasion.

The Firmicutes/Bacteroidetes ratio of the human microbiota changes with age.

BACKGROUND: In humans, the intestinal microbiota plays an important role in the maintenance of host health by providing energy, nutrients, and immunological protection. Applying current molecular methods is necessary to surmount the limitations of classical culturing techniques in order to obtain an accurate description of the microbiota composition. RESULTS: Here we report on the comparative assessment of human fecal microbiota from three age-groups: infants, adults and the elderly. We demonstrate that the human intestinal microbiota undergoes maturation from birth to adulthood and is further altered with ageing. The counts of major bacterial groups Clostridium leptum, Clostridium coccoides, Bacteroidetes, Bifidobacterium, Lactobacillus and Escherichia coli were assessed by quantitative PCR (qPCR). By comparing species diversity profiles, we observed age-related changes in the human fecal microbiota. The microbiota of infants was generally characterized by low levels of total bacteria. C. leptum and C. coccoides species were highly represented in the microbiota of infants, while elderly subjects exhibited high levels of E. coli and Bacteroidetes. We observed that the ratio of Firmicutes to Bacteroidetes evolves during different life stages. For infants, adults and elderly individuals we measured ratios of 0.4, 10.9 and 0.6, respectively. CONCLUSION: In this work we have confirmed that qPCR is a powerful technique in studying the diverse and complex fecal microbiota. Our work demonstrates that the fecal microbiota composition evolves throughout life, from early childhood to old age.

Bacteriotherapy for inflammatory bowel disease: therapeutic tool and/or pharmacological vectors?

Inflammatory bowel diseases are the result of an abnormal immune response to environmental factors including the intestinal microbiota. Epithelial and immune cells of the intestinal mucosa recognise specific bacterial molecules via Toll like and NOD like receptors and this interaction modulates the inflammatory response (activation of the NF-kappaB pathway). It is thus rational to try treatments which could modify the intestinal microbiota i.e. antibiotics, new substrates (prebiotics) or new micro-organisms (probiotics). We review the literature on existing evidence for the efficacy of probiotic strains or combinations in patients with pouchitis (good evidence), ulcerative colitis (fair evidence), and Crohn's disease (no evidence at the present time). We also discuss the mechanisms of action, the use of microbial agents as pharmacological vectors, the development of genetically modified probiotics (including a clinical pilot trial in patients with Crohn's disease), and safety issues.

Correction: Interleukin-22-deficiency and microbiota contribute to the exacerbation of Toxoplasma gondii-induced intestinal inflammation.

The original version of this Article omitted the author Dr Mathias Chamaillard from the l'Institut de Pasteur, Lille, France. This has been corrected in both the PDF and HTML versions of the Article.

[Chronic intestinal pseudo-obstruction and anti-Hu syndrome: 13 years of follow-up without neoplasia]. / Pseudo-obstruction intestinale chronique et syndrome des anti-Hu: 13 ans de suivi sans apparition de néoplasie.

Chronic intestinal pseudo-obstruction (CIPO) is a heterogeneous group of rare disorders characterised by symptoms of intestinal obstruction with no mechanical evidence of obstruction. It is caused by ineffective intestinal contractions due to visceral neuropathy and/or neuropathy. In adults, CIPO is mostly secondary. The most common causes are metabolic disorders, connective tissue disorders, neuropathic drug related injuries, paraneoplasic and post-infectious syndromes and amyloidosis. Secondary forms of CIPO have been reported with anti-Hu antibodies. This corresponds to an antineuronal antibody that recognizes a protein expressed in the nuclei of neuron (ANNA-1) and neoplasic cells. The anti-Hu antibody must be searched for in patients over 40 years old with CIPO (associated with small cell lung cancer in 75% of cases). Recently, the association of CIPO and the anti-Hu antibody has been described without associated neoplasia. We report a case of an association of CIPO and anti-Hu antibody without cancer after 13 years of follow-up.

Interleukin-22-deficiency and microbiota contribute to the exacerbation of Toxoplasma gondii-induced intestinal inflammation.

Upon oral infection with Toxoplasma gondii cysts (76 K strain) tachyzoites are released into the intestinal lumen and cross the epithelial barrier causing damage and acute intestinal inflammation in C57BL/6 (B6) mice. Here we investigated the role of microbiota and IL-22 in T.gondii-induced small intestinal inflammation. Oral T.gondii infection in B6 mice causes inflammation with IFNγ and IL-22 production. In IL-22-deficient mice, T.gondii infection augments the Th1 driven inflammation. Deficiency in either IL-22bp, the soluble IL-22 receptor or Reg3γ, an IL-22-dependent antimicrobial lectin/peptide, did not reduce inflammation. Under germ-free conditions, T.gondii-induced inflammation was reduced in correlation with parasite load. But intestinal inflammation is still present in germ-free mice, at low level, in the lamina propria, independently of IL-22 expression. Exacerbated intestinal inflammation driven by absence of IL-22 appears to be independent of IL-22 deficiency associated-dysbiosis as similar inflammation was observed after fecal transplantation of IL-22-/- or WT microbiota to germ-free-WT mice. Our results suggest cooperation between parasite and intestinal microbiota in small intestine inflammation development and endogenous IL-22 seems to exert a protective role independently of its effect on the microbiota. In conclusion, IL-22 participates in T.gondii induced acute small intestinal inflammation independently of microbiota and Reg3γ.

Efficacy and safety of golimumab in Crohn's disease: a French national retrospective study.

BACKGROUND: Anti-tumour necrosis factor (TNF) agents have improved the care of Crohn's disease (CD). After the first anti-TNF discontinuation, it is possible to switch to another anti-TNF. Three anti-TNF agents are available for ulcerative colitis (infliximab, adalimumab and golimumab), but only the first 2 have been approved for CD because golimumab has not been studied for this indication. AIM: To report the efficacy and safety of golimumab in CD. METHODS: Crohn's disease patients who received golimumab were identified in 12 French tertiary centres and were retrospectively analysed. The primary endpoint was the duration of golimumab treatment before escalation or discontinuation. The clinical response was defined as a decrease of more than 3 points in the Harvey-Bradshaw index or by global physician assessment. RESULTS: One hundred and fifteen patients were included. The golimumab treatment duration was 9.8 months (0.55-44), and 48.7% of the patients were still under treatment at the end of follow-up. Clinical response was observed in 55.8% of the patients after a mean duration of 3.8 months. The probability of remaining under treatment without escalation at 6, 12 and 24 months was 54.6%, 34.9% and 19.3% respectively. In multivariate analysis, discontinuation of the first anti-TNF agent due to intolerance (odds ratio, OR = 2.16; 95% CI, confidence interval [1.25-3.86]; P = .005) and co-immunosuppression for more than 6 months (OR = 3.98; 95% CI [2.3-7.1]; P < .0001) were predictive factors of efficacy. Six per cent of the patients discontinued treatment due to intolerance. CONCLUSION: After failure of infliximab or adalimumab for Crohn's disease, golimumab was safe and seemed beneficial in half of the patients.

Review article: the role of bacteria in onset and perpetuation of inflammatory bowel disease.

We review the evidence that strongly suggests a role of the intestinal microbiota in the onset and perpetuation of inflammatory bowel disease (IBD). Experimental studies consisted of suppressing micro-organisms from the microbiota (using germ-free or gnotoxenic animals or antibiotics), introducing new micro-organisms or microbial components (e.g. probiotics, CpG-DNA) or selectively increasing some endogenous bacteria (e.g. using prebiotics). Intervention studies were performed in patients or animal models of spontaneous or chemically-induced colitis. Information was also obtained from observational studies that described the composition of the faecal and mucosal microbiota at various stages of the disease process and in controls. Many have used culture-independent techniques that identify bacteria based on the nucleic acid sequence of ribosomal RNA molecules. Microbiota in patients with IBD seem to be characterized by high concentrations of bacteria in contact with the mucosa, instability, the presence of high numbers of unusual bacteria and sometimes a reduction in the biodiversity. Studies searching for a generalized or localized dysbiosis in IBD are discussed, as well as those trying to identify bacterial molecules and receptors, which may be implicated in triggering the inflammatory process.