Baseline risk assessment of patients with ulcerative colitis: does initial treatment selection influence outcomes?

BACKGROUND AND AIMS: Treatment of ulcerative colitis (UC) typically follows a step-up approach and targets colonic mucosal healing. Although mucosal healing reduces the risk of colectomy, whether or not early treatment of patients with 'high-risk' features using tumor necrosis factor (TNF) antagonists reduces the risk of colectomy is not clear. Accordingly, we aim to evaluate the effect of baseline treatment selection according to the risk profile on 5-year outcomes and identify predictors of poor outcomes. PATIENTS AND METHODS: Adult patients with confirmed UC were retrospectively identified. Baseline clinical and endoscopic data were collected. Patients were assigned a risk profile on the basis of the presence or absence of 'high-risk' features within the first 6 months of diagnosis including moderate to severe endoscopic disease, frequent need for steroids, steroid dependency, and disease involving the entire colon according to endoscopy. Treatment discordance was defined as treating 'high-risk' patients with medications other than anti-TNF therapy during the first 6 months after diagnosis or treating 'low-risk' patients with anti-TNF therapy within 6 months of diagnosis. The associations between discordance and 5-year colectomy and hospitalization rates were statistically calculated through regression analysis, as were predictors of outcomes. RESULTS: A total of 108 patients were identified and studied. The median age was 36 years (interquartile range=27-50) and the average duration of disease was 6.6 (±3.1) years. Females comprised 62% of the cohort and 30% reported cigarette smoking. Seventy three percent of the patients were placed in the 'high-risk' category. The 5-year risk of colectomy was not statistically significantly higher in patients identified as 'high-risk' compared with those who were 'low-risk' (risk ratio=0.86, 95% confidence interval=0.24-3.1, P=0.81), nor was the 5-year risk of hospitalizations (risk ratio=1.63, 95% confidence interval=0.81-3.30, P=0.15). On the basis of stepwise model selection, colectomy was significantly predicted by discordance (P=0.039), arthritis (P=0.007), baseline stool frequency (P=0.019), Adalimumab use within the first 6 months of diagnosis (P=0.006), and pyoderma gangrenosum (P=0.049); hospitalization was predicted by discordance (P=0.018), baseline albumin concentrations (P=0.005), thromboembolism (P<0.005), thiopurine use within the first 6 months of diagnosis (P<0.005), Adalimumab use within the first 6 months of diagnosis (P=0.003), nationality (P=0.016), endoscopic severity (P=0.007), arthritis (P=0.005), and pyoderma gangrenosum (P=0.025). CONCLUSION: Among other clinical parameters, discordance between baseline risk and treatment selection appears to be a significant predictor of outcomes in UC.

Anti-inflammatory bowel effect of industrial orange by-products in DSS-treated mice.

This work addresses the role of different by-products derived from the industrial extraction of orange juice in a possible anti-inflammatory effect in mice with colitis induced by dextran sulfate sodium (DSS). Fresh orange residue (FOR), dry orange residue (DOR), orange liqueur (OL) and animal feed (AF), as well as commercial citrus pectin (CP), were administered to C57BL/6J mice for 15 days before starting the DSS treatment. Analysis of macroscopic parameters such as the Disease Activity Index (DAI) and the colonic weight/length ratio revealed an anti-inflammatory effect following intake of FOR, AF or CP. Moreover, q-PCR of RNA from colonic tissue indicated measurable changes in the expression of TNF-α, IL-1ß, iNOS, and intercellular adhesion molecules ICAM I, as well as in intestinal barrier proteins such as MUC-3, occludin, and ZO-1. Pectin, phenolic compounds and/or Maillard reaction products formed at initial steps were identified as relevant components exerting the ascribed beneficial effects. Our findings could open up the further application of a variety of orange by-products as food supplements in the potential amelioration of inflammatory bowel diseases.

Assessment of Serum sTREM-1 as a Marker of Subclinical Inflammation in Diarrhea-Predominant Patients with Irritable Bowel Syndrome.

BACKGROUND: Irritable bowel disease (IBS) is viewed upon as a functional disorder of subclinical inflammatory changes in recent years, and there is no reliable biomarker. Triggering receptor expressed on myeloid cells 1 (TREM-1), also produced in a soluble form (sTREM-1), is involved in the activation of inflammatory cascades of intracellular events and may play a role in pathogenesis of IBS. AIM: To investigate whether serum sTREM-1 level can be used as a marker of subclinical inflammation in D-IBS. METHODS: Abdominal pain was quantified by a validated questionnaire. Expression level of TREM-1 in colonic mucosa as well as sTREM-1 level in serum was also detected. Furthermore, we investigated the involvement of TREM-1-associated macrophage activation in IBS-like visceral hypersensitivity. RESULTS: No evidence for obvious inflammation was found in D-IBS patients. Serum sTREM-1 level in D-IBS patients was significantly higher than that in HCs, which was also significantly correlated with abdominal pain scores. We showed a marked increase in the proportion of TREM-1-expressing macrophages in D-IBS, which was significantly correlated with abdominal pain scores. Functionally, gadolinium chloride (GdCl3), a macrophage selective inhibitor, or LP17, the TREM-1-specific peptide, significantly suppressed the visceral hypersensitivity in trinitrobenzene sulfonic acid (TNBS)-treated mice with IBS-like visceral hypersensitivity. CONCLUSIONS: Serum sTREM-1 level is significantly higher in D-IBS patients and positively correlates with abdominal pain, which may be initiated by TREM-1-associated macrophage activation, indicating the existence of subclinical inflammation in D-IBS. Therefore, serum sTREM-1 is a potential marker of subclinical inflammation in D-IBS.

Quantitative assessment of CD30+ lymphocytes and eosinophils for the histopathological differential diagnosis of inflammatory bowel disease.

BACKGROUND AND AIMS: The histopathological discrimination of Crohn's disease [CD] and ulcerative colitis [UC] can be challenging. The aim of this study was to evaluate if quantification of CD30(+) lymphocytes and eosinophils in histopathological material improves the accuracy of diagnosis of inflammatory bowel disease. METHODS: A total of 156 patients were diagnosed with IBD by a gastroenterologist and corroborated by 5 years of follow-up. Patients were treatment naïve at the time of biopsy. Samples were taken from diseased areas of the colon and examined by a gastrointestinal pathologist. RESULTS: The median number of eosinophils in biopsies from affected segments was 42/high power field [hpf] [25.5-63.5] in CD and 98/hpf [67-123] in UC [p < 0.001]. Biopsies containing ≥ 70 eosinophils/hpf field had a sensitivity of 78.3% and a specificity of 71% for the diagnosis of UC ({area under the receiver operating characteristic (ROC) curve 0.767 (95% confidence interval [CI] 0.696-0.838)}. There was a median of three CD30(+) cells/hpf [range 2-6] in diseased CD biopsies and 33 cells/hpf [24-52] in diseased UC biopsies [p < 0.001]. The cut-off determined by the ROC curve was 15 (sensitivity 97.4%, specificity 97.4%, positive likelihood ratio (PLR) 17.1, Negative likelihood ratio (NLR) 0.03, area under the curve [AUC]: 0.978; 95% CI 0.95310.999). CONCLUSIONS: Routine histopathological assessment with quantification of CD30+ cells is highly accurate at discriminating CD and UC. All the measured parameters are easy to perform, low-cost, and available in most pathological laboratories.

Rapid fecal calprotectin level assessment and the SIBDQ score can accurately detect active mucosal inflammation in IBD patients in clinical remission: a prospective study.

BACKGROUND AND AIMS: Mucosal healing is an important predictor of disease-related outcome in patients with inflammatory bowel disease (IBD) patients, including those in clinical remission. However, colonoscopy is an invasive procedure and many patients decline repeated endoscopic examinations. We aimed to assess whether noninvasive biomarkers could accurately detect endoscopic mucosal inflammatory activity in IBD patients in clinical remission. METHODS: We conducted a prospective observational cohort study on IBD patients in clinical remission at Colentina Hospital, Bucharest. Clinical activity was assessed using the Mayo score and Crohn's Disease Activity Index (CDAI), quality of life was assessed using the Short Inflammatory Bowel Disease Questionnaire (SIBDQ). Serum C-reactive protein (CRP) and fecal calprotectin (FC) levels were determined. All patients underwent ileo-colonoscopy to assess mucosal inflammatory activity. RESULTS: 48 patients were included in this study, with 67% showing endoscopic disease activity. SIBD questionnaire and FC performed well as noninvasive markers of intestinal inflammation (AUROC 0.78 and 0.77, respectively), while CRP could not accurately predict endoscopic disease activity. Fecal calprotectin levels > 30 µg/g showed a 93% sensitivity and a 50% specificity for detecting inflammatory changes of the mucosa while a combined test using FC > 30µg/g and a SIBDQ score < 6 achieved 81.2% sensitivity and 75% specificity, respectively, in detecting active endoscopic disease. CONCLUSION: Fecal calprotectin and SIBDQ have good diagnostic accuracy in detecting mucosal inflammatory changes in IBD patients in clinical remission. Combining simple, noninvasive tests such as the SIBDQ and FC levels appears to be a practical method for monitoring disease activity in these patients, possibly reducing the need for repeat endoscopic examinations.

Assessment of the probiotic potential of a dairy product fermented by Propionibacterium freudenreichii in piglets.

Dairy propionibacteria, including Propionibacterium freudenreichii , display promising probiotic properties, including immunomodulation. These properties are highly strain-dependent and rarely studied in a fermented dairy product. We screened 10 strains, grown in a newly developed fermented milk ultrafiltrate, for immunomodulatory properties in vitro. The most anti-inflammatory strain, P. freudenreichii BIA129, was further tested on piglets. P. freudenreichii -fermented product improved food intake and growth of piglets. Colonic mucosa explants of treated pigs secreted less interleukin 8 (-25%, P < 0.05) and tumor necrosis factor α (-20%, P < 0.05), either in basal conditions or after a lipopolysaccharide challenge. By contrast, the gut structure, barrier function (measured ex vivo in Ussing chambers), microbial diversity (assessed by 16S rRNA pyrosequencing), and colonic short-chain fatty acid content were unchanged, assuming maintenance of normal intestinal physiology. In conclusion, this work confirms in vivo probiotic properties of dairy propionibacteria-fermented products, which are promising for the prevention or healing of inflammatory bowel diseases.

Fermentable fiber ameliorates fermentable protein-induced changes in microbial ecology, but not the mucosal response, in the colon of piglets.

Dietary inclusion of fermentable carbohydrates (fCHO) is reported to reduce large intestinal formation of putatively toxic metabolites derived from fermentable proteins (fCP). However, the influence of diets high in fCP concentration on epithelial response and interaction with fCHO is still unclear. Thirty-two weaned piglets were fed 4 diets in a 2 × 2 factorial design with low fCP/low fCHO [14.5% crude protein (CP)/14.5% total dietary fiber (TDF)]; low fCP/high fCHO (14.8% CP/16.6% TDF); high fCP low fCHO (19.8% CP/14.5% TDF); and high fCP/high fCHO (20.1% CP/18.0% TDF) as dietary treatments. After 21-23 d, pigs were killed and colon digesta and tissue samples analyzed for indices of microbial ecology, tissue expression of genes for cell turnover, cytokines, mucus genes (MUC), and oxidative stress indices. Pig performance was unaffected by diet. fCP increased (P < 0.05) cell counts of clostridia in the Clostridium leptum group and total short and branched chain fatty acids, ammonia, putrescine, histamine, and spermidine concentrations, whereas high fCHO increased (P < 0.05) cell counts of clostridia in the C. leptum and C. coccoides groups, shifted the acetate to propionate ratio toward acetate (P < 0.05), and reduced ammonia and putrescine (P < 0.05). High dietary fCP increased (P < 0.05) expression of PCNA, IL1ß, IL10, TGFß, MUC1, MUC2, and MUC20, irrespective of fCHO concentration. The ratio of glutathione:glutathione disulfide was reduced (P < 0.05) by fCP and the expression of glutathione transferase was reduced by fCHO (P < 0.05). In conclusion, fermentable fiber ameliorates fermentable protein-induced changes in most measures of luminal microbial ecology but not the mucosal response in the large intestine of pigs.

IL-22 mediates host defense against an intestinal intracellular parasite in the absence of IFN-γ at the cost of Th17-driven immunopathology.

The roles of Th1 and Th17 responses as mediators of host protection and pathology in the intestine are the subjects of intense research. In this study, we investigated a model of intestinal inflammation driven by the intracellular apicomplexan parasite Eimeria falciformis. Although IFN-γ was the predominant cytokine during E. falciformis infection in wild-type mice, it was found to be dispensable for host defense and the development of intestinal inflammation. E. falciformis-infected IFN-γR(-/-) and IFN-γ(-/-) mice developed dramatically exacerbated body weight loss and intestinal pathology, but they surprisingly harbored fewer parasites. This was associated with a striking increase in parasite-specific IL-17A and IL-22 production in the mesenteric lymph nodes and intestine. CD4(+) T cells were found to be the source of IL-17A and IL-22, which drove the recruitment of neutrophils and increased tissue expression of anti-microbial peptides (RegIIIß, RegIIIγ) and matrix metalloproteinase 9. Concurrent neutralization of IL-17A and IL-22 in E. falciformis-infected IFN-γR(-/-) mice resulted in a reduction in infection-induced body weight loss and inflammation and significantly increased parasite shedding. In contrast, neutralization of IL-22 alone was sufficient to increase parasite burden, but it had no effect on body weight loss. Treatment of an E. falciformis-infected intestinal epithelial cell line with IFN-γ, IL-17A, or IL-22 significantly reduced parasite development in vitro. Taken together, to our knowledge these data demonstrate for the first time an antiparasite effect of IL-22 during an intestinal infection, and they suggest that IL-17A and IL-22 have redundant roles in driving intestinal pathology in the absence of IFN-γ signaling.

Molecular signature of kappa-carrageenan mimics chondroitin-4-sulfate and dermatan sulfate and enables interaction with arylsulfatase B.

The common food additive kappa-carrageenan (κ-CGN) is a sulfated polysaccharide that resembles chondroitin-4-sulfate (C4S) and dermatan sulfate (DS). All have a sulfate group on C4 of a glycoside (galactose for CGN and N-acetylgalactosamine for C4S), and the sulfate-bearing glycoside is linked in a ß-1,4-configuration to an unsulfated, six-carbon sugar (galactose for CGN, glucuronate for C4S and iduronate for DS). The enzyme arylsulfatase B (ARSB; N-acetylgalactosamine-4-sulfate) is the highly selective enzyme that removes the four-sulfate group from the nonreducing terminus of C4S and DS, thereby regulating subsequent degradation. In this report, κ-CGN is shown to be a substrate for recombinant human ARSB (rhARSB). Sulfate was generated from both C4S and κ-CGN following incubation with rhARSB. Exposure of human colonic epithelial cells to κ-CGN, but not to C4S, produced reactive oxygen species (ROS) and increased interleukin (IL)-8 secretion. The ROS production from κ-CGN was reduced by exposure to rhARSB, but increased by competition from C4S or DS, but not from chondroitin-6-sulfate. Prior treatment of either lambda- or iota-CGN with rhARSB had no impact on ROS, IL-8 or inorganic sulfate production, demonstrating a specific effect of the molecular configuration of κ-CGN. By mimicry of C4S and DS and by interaction with ARSB, κ-CGN can directly interfere with the normal cellular functions of C4S, DS and ARSB. Since C4S and DS are present in high concentration in tissues, the impact of κ-CGN exposure may be due to some extent to interference with the normal biological functions of ARSB, C4S and DS.

Assessment of Lactobacillus gasseri as a candidate oral vaccine vector.

Lactobacillus species are commensal bacteria that have long been recognized as probiotic microbes and are generally regarded as safe (GRAS) for human consumption. We have investigated the use of L. gasseri as a vaccine vector for oral immunization against mucosal pathogens. Recent research has shown that the immune response to different lactobacilli can vary widely depending on the species or subspecies of Lactobacillus being studied. While some lactobacilli seem to induce oral tolerance, others induce an adaptive immune response. This study characterized the systemic and mucosal immune response to wild-type and genetically modified L. gasseri. L. gasseri primarily activates TLR2/6, with additional activation through the TLR2 homodimer. To expand the Toll-like receptor (TLR) activation profile of L. gasseri and the immunogenicity of the vector, a plasmid containing fliC, the gene encoding bacterial flagellin, was introduced which resulted in the strong activation of TLR5. The treatment of human myeloid dendritic cells with recombinant lactobacilli expressing flagellin triggered phenotypic maturation and the release of proinflammatory cytokines. In contrast, bacterial treatment also resulted in a statistically significant increase in IL-10 production. In vivo studies established that treatment with L. gasseri led to a diversification of B-cell populations in the lamina propria of the murine colon. Furthermore, treatment with genetically modified L. gasseri led to a significant decrease in the percentage of FoxP3(+) colonic lymphocytes. Taken together, these data clarify the interaction of L. gasseri with the host immune system and support further investigation of the in vivo immunogenicity of L. gasseri expressing both flagellin and candidate vaccine antigens.

Chronological assessment of mast cell-mediated gut dysfunction and mucosal inflammation in a rat model of chronic psychosocial stress.

Life stress and mucosal inflammation may influence symptom onset and severity in certain gastrointestinal disorders, particularly irritable bowel syndrome (IBS), in connection with dysregulated intestinal barrier. However, the mechanism responsible remains unknown. Crowding is a validated animal model reproducing naturalistic psychosocial stress, whose consequences on gut physiology remain unexplored. Our aims were to prove that crowding stress induces mucosal inflammation and intestinal dysfunction, to characterize dynamics in time, and to evaluate the implication of stress-induced mast cell activation on intestinal dysfunction. Wistar-Kyoto rats were submitted to 15 days of crowding stress (8 rats/cage) or sham-crowding (2 rats/cage). We measured spontaneous and corticotropin-releasing factor-mediated release of plasma corticosterone. Stress-induced intestinal chrono-pathobiology was determined by measuring intestinal inflammation, epithelial damage, mast cell activation and infiltration, and intestinal barrier function. Corticosterone release was higher in crowded rats throughout day 15. Stress-induced mild inflammation, manifested earlier in the ileum and the colon than in the jejunum. While mast cell counts remained mostly unchanged, piecemeal degranulation increased along time, as the mucosal content and luminal release of rat mast cell protease-II. Stress-induced mitochondrial injury and increased jejunal permeability, both events strongly correlated with mast cell activation at day 15. Taken together, we have provided evidences that long-term exposure to psychosocial stress promotes mucosal inflammation and mast cell-mediated barrier dysfunction in the rat bowel. The notable resemblance of these findings with those in some IBS patients, support the potential interest and translational validity of this experimental model for the research of stress-sensitive intestinal disorders, particularly IBS.

Modulation of the microbial ecology of the human colon by probiotics, prebiotics and synbiotics to enhance human health: an overview of enabling science and potential applications.

The application of probiotics and prebiotics to the manipulation of the microbial ecology of the human colon has recently seen many scientific advances. The sequencing of probiotic genomes is providing a wealth of new information on the biology of these microorganisms. In addition, we are learning more about the interactions of probiotics with human cells and with pathogenic bacteria. An alternative means of modulating the colonic microbial community is by the use of prebiotic oligosaccharides. Increasing knowledge of the metabolism of prebiotics by probiotics is allowing us to consider specifically targeting such dietary intervention tools at specific population groups and specific disease states.

Phenotypic and functional assessment of intraepithelial lymphocytes (IEL) isolated from rat colon and small bowel.

We have compared the proliferative potential of IELs isolated from rat colon (CIEL) and small bowel (SBIEL), and compared this with that observed using spleen lymphocytes. Unless additional irradiated spleen cells were added as a source of accessory cells, both IEL populations show poor proliferation in response to Con A stimulation. The CD4/CD8 ratio in spleen, SBIEL and CIEL was markedly different (3:1, 1:3, and 1:1, respectively). Cells expressing surface markers characteristic of macrophages were not routinely found in SBIELs. Both IEL preparations inhibited spleen cell proliferation in response to Con A or immobilized anti-CD3, and produced a soluble factor(s) capable of causing similar inhibition. For CIEL this inhibition was dependent upon a proliferation-independent but cell-cell contact dependent event.