Participation of the intestinal microbiota in the mechanism of beneficial effect of treatment with synbiotic Syngut on experimental colitis under stress conditions.

Gut-brain axis plays a central role in the regulation of stress related diseases such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD). It is increasingly recognized that stress modulates gut microbiota community structure and activity and represents an important causal factor in dysbiosis. This study was designed to determine the effect of daily treatment with synbiotic (Syngut) containing inulin, Lactobacillus acidophilus, Bifidobacterium lactis W51, Lactobacillus plantarum W21 and Lactococcus lactis applied i.g. at a dose of 50 mg/kg i.g. on the colonic damage and colonic mucosal blood flow in rats with experimentally induced TNBS-colitis that were additionally exposed or not to acute stress (episodes of cold restraint stress every other day before colitis induction). Control rats received daily treatment with vehicle (saline, i.g.) or mesalazine (50 mg/kg-d i.g.), the standard drug recommended in therapy of IBD. At the termination of TNBS colitis, the histologic evaluation of colonic mucosa, mucosal malonyldialdehyde (MDA) level and plasma concentrations of proinflammatory cytokines (TNF-α, IL-1ß) and adipokine adiponectin were assessed. the samples of colonic mucosa not involving colonic lesions and surrounding the flared mucosa were excised for the determination of mRNA expression for proinflammatory biomarkers TNF-α, IL-1ß, IL-10 and COX-2 as well as antioxidazing factors SOD-1 and SOD-2. Finally, the gut microbial profiles were analyzed by 16S rRNA sequencing at phylum, family and genus level. Episodes of cold stress significantly aggravated the course of TNBS colitis, and significantly increased the release of proinflammatory cytokines as well as the significant increase in the MDA concentration has been observed as compared with non-stressed TNBS rats. These changes were followed by the significant fall in the CBF and plasma adiponectin levels and by the overexpression of mRNA of proinflammatory biomarkers. Synbiotic treatment with Syngut significantly reduced the area of colonic lesions observed macroscopically and microscopically in rats with TNBS colitis with or without exposure to cold stress, significantly increased the CBF, normalized plasma adiponectin levels and significantly attenuated the release and colonic expression of proinflammatory cytokines and biomarkers. the analysis of the gut microbiota showed a significant reduction of microbial diversity (Shannon index) in rats with TNBS colitis with or without exposure to stress. The therapy with Syngut failed to significantly affect the alpha diversity. At the phylum level, the significant rise in Proteobacteria has been observed in stressed rats with TNBS colitis and this effects was attenuated by treatment with Syngut. At family level, TNBS colitis alone or in combination with stress led to a significant decrease of SCFA producing bacterial taxa such as Ruminococaceae and Lachnospiraceae and Syngut counteracted this effect. We conclude that: 1) cold stress exacerbates the gastrointestinal inflammation in experimental colitis; 2) the synbiotic therapy with Syngut ameliorates the gut inflammation in rats with TNBS colitis combined with cold stress; 3) the beneficial effect of Syngut is accompanied by increase of anti-inflammatory taxa such as Ruminococaceae and Lachnospiraceae, and 4) the modulation of gut microbiota with Syngut alleviates stress-related intestinal inflammation suggesting a potential usefulness of synbiotic therapy in intestinal disorders accompanied by stress in patients with IBD.

Microbial patterns in patients with histamine intolerance.

Histamine intolerance represents a controversially discussed disorder. Besides an impaired degradation of orally supplied histamine due to diamine oxidase (DAO) deficiency, a deranged gut flora may also contribute to elevated histamine levels. Our aim was to determine the intestinal bacterial composition in patients with proven histamine intolerance in comparison to other food intolerances and healthy controls. A total of 64 participants were included in the study, encompassing 8 patients with histamine intolerance (HIT), 25 with food hypersensitivity (FH), 21 with food allergy and 10 healthy controls (HC). All participants underwent blood testing for total and food-specific immunoglobulin E, plasma histamine and DAO serum activity. Stool samples were used to analyze stool histamine and zonulin levels and bacterial composition by 16s rRNA sequencing. No significant differences in stool histamine levels were observed, but HIT patients showed elevated levels of stool zonulin. Microbiota analysis revealed increased levels of Proteobacteria (5.4%) and a significantly reduced alpha-diversity in the HIT group (P = 0.019). On family level, HC showed a significantly higher abundance of Bifidobacteriaceae compared to other study groups (P = 0.005), with lowest levels in the HIT group (P = 0.036). Also significantly reduced abundances of the genera Butyricimonas (P = 0.026) and Hespellia (P = 0.025) were observed in the HIT patients, whereas Roseburia were significantly elevated (P = 0.021). We concluded that the altered occurrence of Proteobacteria and Bifidobacteriaceae, reduced alpha-diversity as well as elevated stool zonulin levels suggest a dysbiosis and intestinal barrier dysfunction in histamine intolerant patients, which in turn may play an important role in driving disease pathogenesis.

Successful therapy of Clostridium difficile infection with fecal microbiota transplantation.

Clostridium difficile infection (CDI) is the most common cause of infectious diarrhea and represents an important burden for healthcare worldwide. Symptoms of severe CDI include watery, foul-smelling diarrhea, peripheral leucocytosis, increased C-reactive protein (CRP), acute renal failure, hypotension and pseudomembranous colitis. Recent studies indicate that the main cause of CDI is dysbiosis, an imbalance in the normal gut microbiota. The restoration of a healthy gut microbiota composition via fecal microbiota transplantation (FMT) recently became more popular. The aim of the present study was to assess the effect of FMT on the healing of CDI and to analyze the changes in the level of pro-inflammatory markers (C-reactive protein, fecal calprotectin) and pro-inflammatory cytokines. Eighteen patients with CDI were included in our study (6 males and 12 females) with recurrent and/or severe CDI. The FMT was performed in 17 patients using colonoscopy, including 16 patients receiving a one-time FMT and 1 patient who needed 2 additional FMTs. One patient was treated with a single round of FMT using push-and-pull enteroscopy. In all CDI patients, before and 3 weeks after FMT, the following parameters were analyzed: C-reactive protein, fecal calprotectin, and plasma interleukin (IL)-6, IL-8 and IL-12, and tumor necrosis factor-alpha (TNF-α). In addition, the plasma level of LL-37, a cathelicidine peptide was assessed by fluorescence-activated cell sorting (FACS) before and 3 months after FMT. Finally, in 7 patients a microbiome analysis was performed by sequencing of 16SrRNA in stool probes obtained before and 3 weeks after FMT. The healing rate of CDI was 94%. In all successfully treated patients no recurrent CDI was observed during follow-up (16 months). The serum level of pro-inflammatory cytokines (TNF-α, IL-1ß, IL-6, IL-8 and IL-12) significantly decreased after FMT. Similarly, CRP and fecal calprotectin normalized after FMT. 3 months after FMT a significant increase of LL-37 in the plasma of successfully treated patients was monitored. The sequencing analysis demonstrated an elevated abundance of beneficial bacterial species such as Lactobacillaceae, Ruminococcaceae, Desulfovibrionaceae, Sutterellaceae and Porphyromonodacea after FMT. No serious side effects were observed. We concluded that FMT represented a very effective and safe treatment of recurrent and/or severe CDI and led to favorable shifts in the composition of gut microbiome.

Isolation and characterization of circulating tissue transglutaminase-specific T cells in coeliac disease.

Tissue transglutaminase (TG2) was identified as the humoral autoantigen in coeliac disease, but whether it can also serve as T cell autoantigen is still unknown. We aimed, therefore, to firstly explore the presence of TG2-specific T cells in peripheral blood of ten adult patients (four active, i.e. carrying both serological and histological features of the disease; four treated, i.e. with proven mucosal recovery and disappearance of specific antibodies after an adequate period of gluten free diet; and two potential coeliacs, i.e. carrying the serological stigmata of the disease, but not the intestinal lesions), and four healthy controls (two carrying the HLA-DQ2 haplotype of susceptibility to the disease), and secondly to carry out a detailed in vitro characterization of the isolated antigen-specific T cells. T cell lines were first established by means of weekly stimulation with human recombinant TG2 followed by generation of T cell clones through distribution of T cells on plates at one cell/well limiting dilution and further rounds of stimulation. Antigen specificity and HLA-DQ2 restriction were both assessed by evaluating the proliferative response to TG2 in the absence and presence of human sera blocking HLA-DQ2 molecules, after exclusion of impurities in the antigen preparation. Immune phenotyping of T cell clones was performed by flow cytometry, and the expression of IL-1â, IL-4, IL-6, IL-10, IL-12, TGF-beta, IFN-gamma and TNF-alpha was determined by ELISA assay on the supernatants of these clones. A total of 91 T cell clones were isolated from the three HLA-DQ2-positive, active patients, but none from the other patients and controls. The immune phenotyping showed that the majority of them (85.7 percent) were CD3/CD4+ and only a small percentage (14.3 percent) were CD3/CD8+, all carried the TCR alphabeta, and had a memory phenotype. The cytokine profile showed high levels of IFN-gamma and IL-6 that, together with the absence of IL-4, placed these T cell clones in the T helper type 1-like category. Further in vitro analysis was carried out on 32/91 CD4+ clones and showed a specific and dose-dependent proliferative response towards TG2 and an HLA-DQ2 restriction. Finally, when incubating duodenal mucosal specimens of treated patients with the supernatant of TG2-specific T cell clones, characteristic disease lesions were found, indicating a role for TG2-specific cellular immune response in the pathogenesis of coeliac disease.

Soft particle model for block copolymers.

A soft particle model for diblock (AB) copolymer melts is proposed. Each molecule is mapped onto two soft spheres built by Gaussian A- and B-monomer distributions. An approximate analytical expression for the joint distribution function for the distance between both spheres and their radii of gyration is derived, which determines the entropic contribution to the intramolecular free energy. Adding a mean-field expression for the intermolecular interactions, we obtain the total free energy of the system. Based on this free energy, Monte Carlo simulations are carried out to study the kinetics of microphase ordering in the bulk and its effect on molecular diffusion. This is followed by an analysis of thin films, with emphasis on pattern transfer from walls with a periodic structure. It is shown that the level of coarse graining in the soft particle model is suitable to describe structural and kinetic properties of copolymers on mesoscopic scales.

Cross linking to tissue transglutaminase and collagen favours gliadin toxicity in coeliac disease.

BACKGROUND AND AIMS: Intestinal inflammation in coeliac disease is driven by the gluten fraction of wheat proteins. Deamidation or cross linking of gluten peptides by tissue transglutaminase (tTG), the coeliac disease autoantigen, creates potent T cell stimulatory peptides. Therefore, our aim was to identify the reaction patterns of gluten peptides, intestinal extracellular matrix proteins, and tTG. METHODS: tTG activity was analysed by incorporation of monodansyl cadaverine into gliadins. Fluorescence labelled tTG reactive short gliadin peptides were used to demonstrate their deamidation and explore their cross linking patterns with tTG itself or extracellular matrix proteins. Patient sera and controls were checked for autoantibodies to matrix proteins. RESULTS: Gliadins alpha1-alpha11, gamma1-gamma6, omega1-omega3, and omega5 were substrates for tTG. tTG catalysed the cross linking of gliadin peptides with interstitial collagen types I, III, and VI. Coeliac patients showed increased antibody titres against the collagens I, III, V, and VI. CONCLUSIONS: tTG formed high molecular weight complexes with all tested gliadins. As all tested gliadins were substrates for tTG, the tTG catalysed modifications were not restricted to single gliadin types and epitopes. Furthermore, haptenisation and long term immobilisation of gliadin peptides by tTG catalysed binding to abundant extracellular matrix proteins could be instrumental in the perpetuation of intestinal inflammation and some associated autoimmune diseases in coeliac disease.

Coupled ion and network dynamics in polymer electrolytes: Monte Carlo study of a lattice model.

Monte Carlo simulations are used to study ion and polymer chain dynamic properties in a simplified lattice model with only one species of mobile ions. The ions interact attractively with specific beads in the host chains, while polymer beads repel each other. Cross linking of chains by the ions reduces chain mobilities which in turn suppresses ionic diffusion. Diffusion constants for ions and chains as a function of temperature follow the Vogel-Tammann-Fulcher (VTF) law with a common VTF temperature at low ion concentration, but both decouple at higher concentrations, in agreement with experimental observations. Our model allows us to introduce pressure as an independent variable through calculations of the equation of state using the quasichemical approximation, and to detect an exponential pressure dependence of the ionic diffusion.

Autoantibodies of patients with coeliac disease are insufficient to block tissue transglutaminase activity.

BACKGROUND AND AIMS: Coeliac disease (CD) is characterised by the presence of autoantibodies against tissue transglutaminase (tTG), the endomysial autoantigen. This study was performed to determine the effect of purified autoantibodies on the enzymatic activity of tTG. METHODS: Total IgA and IgG class antibodies and purified anti-tTG autoantibodies were isolated from sera of untreated patients with CD and controls. The inhibitory capacity of the antibodies on tTG activity was checked by a fluorometric assay based on the incorporation of monodansyl cadaverine into casein and by tTG-catalysed cross linking of biotinylated cadaverine to gliadin. RESULTS: The enriched IgA and IgG fractions of five patients with CD and three controls resulted in no significantly different inhibition of enzymatic activity. In contrast, the use of affinity purified anti-tTG autoantibodies of 12 patients with CD led to a dose dependent reduction of tTG activity, compared to control immunoglobulins (n=6). However, the remaining activity was sufficient for cross linking of cadaverine into gliadin, and enzymatic tTG activity was only blocked completely by high concentrations of a monoclonal antibody, which is directed to the active centre of tTG. CONCLUSIONS: Despite a partial inhibitory effect of isolated anti-tTG autoantibodies from patients with CD, residual enzymatic activity remains sufficiently high to cast doubt on their in vivo relevance.

Kinetics in one-dimensional lattice gas and Ising models from time-dependent density-functional theory.

Time-dependent density-functional theory, proposed recently in the context of atomic diffusion and nonequilibrium processes in solids, is tested against Monte Carlo simulation. In order to assess the basic approximation of that theory, the representation of nonequilibrium states by a local equilibrium distribution function, we focus on one-dimensional lattice models, where all equilibrium properties can be worked exactly from the known free energy as a functional of the density. This functional determines the thermodynamic driving forces away from equilibrium. In our studies of the interfacial kinetics of atomic hopping and spin relaxation, we find excellent agreement with simulations, suggesting that the method is also useful for treating more complex problems.

Density correlations in lattice gases in contact with a confining wall

A discrete version of classical density functional theory applicable to lattice gases or Ising spin systems is proposed, which accounts for the requirement of particle-hole symmetry in the presence of pairwise forces. Results of our theory for density profiles and two-particle correlation functions in two-dimensional strip geometries compare favorably with Monte Carlo simulations. Some problems with standard "weighted-density" approximation schemes, when applied to lattice gases, are pointed out.

Autoantibodies to tissue transglutaminase are sensitive serological parameters for detecting silent coeliac disease in patients with Type 1 diabetes mellitus.

AIMS: To investigate the clinical significance of the determination of IgA antibodies to tissue transglutaminase (tTG) for the detection of silent coeliac disease in patients with Type 1 diabetes mellitus. METHODS: A total of 520 patients with diabetes (median age 14.2 years, range 1-27) were tested for IgA antibodies to tTG (IgA anti-tTG, ELISA), endomysium (EmA, indirect immunofluoresence) and gliadin (IgA-AGA, enzyme immunometric assay) after ruling out IgA deficiency. RESULTS: The prevalence of IgA anti-tTG among patients with diabetes was 4.4% (23 of 520), and that of EmA and IgA-AGA 3.5% (18 of 520, respectively). The coefficient of agreement between IgA anti-tTG and EmA was high (Cohen's kappa = 0.87, P < 0.001). Thirteen of the 23 IgA anti-tTG-positive patients underwent duodenal biopsy. Coeliac disease was confirmed in nine of 13 patients. One of them was negative for EmA and AGA, but positive for IgA anti-tTG. Retrospective annual determinations up to 8 years in six IgA anti-tTG-positive patients showed both permanent and transient elevations of the serological markers. CONCLUSIONS: These data show that a positive IgA antibody test to tTG is a more sensitive parameter than EmA for silent coeliac disease in patients with diabetes. Confirmatory small bowel biopsy, however, remains necessary for diagnosis as some patients with positive antibodies may be without histological changes.

Serum antibodies in celiac disease.

Celiac disease is characterized by small intestinal damage which often leads to global malabsorption. For diagnosis an intestinal biopsy to demonstrate the mucosal changes is mandatory. However, serological tests are useful additional tools to confirm the diagnosis and to monitor therapy. These serological tests, which are based on the detection of antibodies against gliadin and autoantibodies against components of the extracellular matrix, are described in this article.

Immunoassay for detection of IgA antitissue transglutaminase in patients with celiac disease.

Celiac disease is characterized by mucosal changes in the small intestine, ranging from increased numbers of intraepithelial lymphocytes to complete villus effacement with various signs of malabsorption (1,2). Celiac disease is diagnosed by the demonstration of an altered intestinal mucosa in a jejunal biopsy specimen (3). Celiac disease patients invariably have antibodies directed against gliadin and endomysium, a structural component of the extracellular matrix: both antibodies disappear under a gluten-free diet. Therefore, these antibodies are useful tools for diagnosis, and in the dietary control of coeliac disease (3-7). Serum IgA antibodies against endomysial antibodies (EMAs) are especially considered to be sensitive and highly specific markers for celiac disease (8)(9). Previously, EMAs were detected by indirect immunofluorescence on tissue slides of monkey esophagus or human umbilical cord (10-12).

Circulating autoantibodies to tissue transglutaminase differentiate patients with dermatitis herpetiformis from those with linear IgA disease.

BACKGROUND: Dermatitis herpetiformis (DH) is highly associated with celiac disease. Recently, tissue transglutaminase (tTG) was identified as the autoantigen of IgA antibodies in celiac disease. The prevalence of antibodies to tTG in DH patients is not known. OBJECTIVE: The purpose of this study was to determine whether DH patients show circulating IgA autoantibodies to tTG, to compare their serum levels with those from patients with other subepidermal autoimmune bullous diseases, and to correlate levels of antibodies to tTG with the extent of small bowel disease. METHODS: Sera were obtained from consecutive patients with DH (n = 11), linear IgA disease (n = 15), bullous pemphigoid (n = 10), and epidermolysis bullosa acquisita (n = 6) and were studied by indirect immunofluorescence on monkey esophagus and NaCl-split human skin. IgA reactivity to tTG was measured by enzyme-linked immunosorbent assay. The extent of mucosal involvement in jejunal biopsy specimens was assessed according to the grading of Marsh. RESULTS: All untreated DH patients showed circulating IgA autoantibodies to tTG. One DH patient already undergoing therapy, the 15 patients with linear IgA disease, and all other controls revealed no autoantibodies to tTG. In addition, serum levels of IgA anti-tTG antibodies reflected the degree of histopathologic changes in jejunal mucosa from biopsy specimens in DH patients. CONCLUSION: Our results show that circulating IgA autoantibodies to tTG are detectable in DH but not in linear IgA disease or other subepidermal autoimmune bullous diseases. The levels of IgA anti-tTG antibodies reflect the extent of histopathologic changes of the jejunal mucosa in DH.

Antibodies to tissue transglutaminase as serologic markers in patients with dermatitis herpetiformis.

Dermatitis herpetiformis is a gluten-sensitive disease with a symmetrically distributed blistering over extensor surfaces. The association with celiac disease is further supported by the high rate of immunoglobulin A autoantibodies to endomysium in patients with dermatitis herpetiformis, which are highly specific and sensitive indicators of celiac disease. Therefore, we determined immunoglobulin A antibodies to tissue transglutaminase, the recently discovered endomysial autoantigen in celiac disease, in patients with dermatitis herpetiformis and controls. Sera of 61 patients with dermatitis herpetiformis, as characterized by granular immunoglobulin A deposits in the subepidermal basement membrane and known endomysial antibody titers (determined by indirect immunofluorescence) as well as 84 control sera of patients with dermal or intestinal diseases unrelated to dermatitis herpetiformis, were analyzed for circulating immunoglobulin A antibodies to tissue transglutaminase by enzyme-linked immunosorbent assay. Immunoglobulin A anti-tissue transglutaminase titers in patients with dermatitis herpetiformis were significantly elevated above the controls. Furthermore, the immunoglobulin A anti-tTG titers showed a positive correlation with semiquantitative endomysial antibody data. Compared with endomysial antibodies, determination of immunoglobulin A anti-tissue transglutaminase reached a specificity and sensitivity of 97.6% and 89.1%. Patients with dermatitis herpetiformis have elevated immunoglobulin A autoantibodies to tissue transglutaminase, confirming its pathogenic relation with celiac disease and further supporting the usefulness of this novel assay for screening and therapy control.

Autoantibodies to tissue transglutaminase as predictors of celiac disease.

BACKGROUND & AIMS: Immunoglobulin A (IgA) autoantibodies to endomysium (EMA) are highly specific and sensitive markers for celiac disease. Recently, we identified tissue transglutaminase (tTG) as the major if not sole endomysial autoantigen. METHODS: An enzyme-linked immunosorbent assay (ELISA) was established to measure IgA anti-tTG titers in serum samples from 106 celiac patients with partial or subtotal villous atrophy, 43 celiac patients on a gluten-free diet, and 114 diseased and healthy controls. Results were correlated with clinical and histological data and with EMA titers. RESULTS: In patients with biopsy-proven celiac disease consuming a normal, gluten-containing diet, 98.1% of the serum samples had elevated IgA titers against tTG, whereas 94.7% of the control sera were negative. IgA anti-tTG correlated positively with semiquantitative IgA EMA titers (r = 0.862; P < 0.0001). CONCLUSIONS: An ELISA based on tTG allows diagnosis of celiac disease with a high sensitivity and specificity. IgA anti-tTG and IgA EMA show an excellent correlation, further confirming the enzyme as the celiac disease autoantigen. Because the assay is quantitative, not subjected to interobserver variation, and easy to perform, it will be a useful tool for population screening of a hitherto underdiagnosed disease.