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Background: Despite adequate treatment, a subgroup of patients with inflammatory bowel disease (IBD), including Crohn`s disease and ulcerative colitis, have persistent gastrointestinal symptoms that are not always related to mucosal damage. Recently, two autoantibodies, anti-CdtB and anti-vinculin, were validated as post-infectious IBS (PI-IBS) markers, however there is limited evidence of its diagnostic role in IBD population., Methods: Patients with more than 3 bowel movements/day and indication of colonoscopy were enrolled. Samples were collected at the time of colonoscopy for assessment of serum levels of anti-CdtB and anti-vinculin antibodies., Results: A total of 160 subjects were included in 4 groups: active IBD (n = 44); quiescent IBD and chronic diarrhea IBD-IBS (n = 25); predominant-diarrhea IBS (n = 45) and controls (n = 46). The mean value of the optical density for anti-CdtB was 1.2 ± 0.65 in group 1, 1.27 ± 0.64 in group 2, 1.49 ± 0.47 in the group 3 and 1.6 ± 0.68 in group 4, p = 0.012. For anti-vinculin, optical densities were: 1.34 ± 0.78 in group 1, 1.46 ± 0.92 in group 2, 1.31 ± 0.79 in group 3 and 1.41 ± 0.86 for controls (p = 0.875). Using a cut-off of 1.56 for anti-CdtB, the positivity between groups was n = 10 (22.7%) in group 1, n = 9 (34.6%) in group 2, 19 (43.2%) in group 3, 21 (45.7%) in group 4 (p = 0.106). The positivity of anti-vinculin using a cut-off of 1.6 was n = 18 (40.9%) in group 1, n = 11 (42.3%), n = 15 (34.1%), n = 22 (47.8%) (p = 0.622)., Conclusions: Our findings show that anti-CdtB and anti-vinculin could not identify IBD-IBS patients or discriminate IBS-D from healthy controls., Competing Interests: Declarations. Ethics approval and consent to participate: The study was approved by the Institutional Ethics Review Board of Clinics Hospital, University of São Paulo School of Medicine. Written informed consent was obtained from patients before enrollment. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Background: Irritable bowel syndrome (IBS) is a common disease with unknown etiology. Poor dietary intake with nutritional deficiency and overweight have been described to increase the risk of IBS. The aim of the present study was to compare weight and circulating levels of micronutrients in IBS compared with healthy controls., Design: Cross-sectional study., Methods: Patients diagnosed with IBS and healthy volunteers were recruited. Participants had to complete a dietary diary book and the questionnaires Rome IV, IBS-severity scoring system (IBS-SSS), and visual analog scale for IBS (VAS-IBS). Weight and height were measured, and blood samples were drawn. C-reactive protein (CRP), cobalamin, folate, iron, total iron-binding capacity (TIBC), and 25-hydroxy (25-OH) vitamin D were analyzed. Differences were calculated between groups and generalized linear model for regressions was adjusted for false discovery rate (FDR)., Results: IBS patients (n = 260) were elder than controls (n = 50) (44.00 (33.25-56.00) vs. 37.85 (30.18-45.48) years; p = 0.012). After adjustment for age, both weight (β: 5.880; 95% CI: 1.433-10.327; p = 0.010, FDR = 0.020) and body mass index (BMI) (β: 2.02; 95% CI: 0.68-3.36; p = 0.003, FDR = 0.012) were higher in patients. Among IBS participants, 48.1% were overweight/obese compared with 26.0% in controls (p = 0.007). Diarrhea-predominated IBS had highest weight (p < 0.001) and BMI (p = 0.077). CRP and cobalamin were higher in patients than controls (p = 0.010 vs. p = 0.007), whereas folate was highest in controls (p = 0.001). IBS patients had lower intake of vegetables (p = 0.026), dairy products (p = 0.004), and cereals (p = 0.010) compared with controls. Despite 21.5% of IBS patients were taking vitamin D supplements, 23.65% of them had vitamin D levels below 50 nmol/L, compared with 26.0% observed in the control group (p = 0.720). Vitamin D levels were lower in overweight than in normal weight IBS patients (60 (48-73) nmol/L vs. 65 (53-78) nmol/L, p = 0.022). Vitamin D correlated with cobalamin and folate but correlated inversely with TIBC and BMI. IBS patients had a high degree of gastrointestinal and extraintestinal symptoms, which were inversely associated with iron levels. Extraintestinal symptoms were associated with increased BMI., Conclusion: IBS patients were often overweight or obese, with low vitamin D levels. High burden of extraintestinal symptoms were associated with overweight and lower iron levels., Registration: ClinicalTrials.gov, NCT05192603 (Date of registration 11/29/2021) and NCT03306381 (Date of registration 09/18/2017), respectively., (© 2024. The Author(s).)

Background: Patients with Irritable Bowel Syndrome (IBS) often relate their symptoms to the intake of food and modify their diet. IgE-mediated food allergy is uncommon in IBS, but the role of IgG-mediated food hypersensitivity remains inconclusive. The primary aim of this study was to compare food- and yeast-specific IgG and IgG4 antibodies in subjects with and without IBS., Methods: This was a case control study in the general population for which subjects completed questionnaires about abdominal complaints and their intake of common food items. Blood samples were collected, and food- and yeast-specific IgG and IgG4 antibodies were measured. Antibodies were measured in mg/L., Results: We included 269 subjects with IBS and 277 control subjects. After correction for subject characteristics and diet, there were no significant differences with regard to food- and yeast-specific IgG and IgG4 antibodies between subjects with IBS and controls. Lower values of IgG antibodies against egg (OR 0.99 (0.98 to 1.00), p = 0.002) and beef (OR 0.75 (0.60 to 0.94), p = 0.012) and higher values of IgG antibodies against chicken (OR 1.14 (1.03 to 1.27), p = 0.009) were associated with more severe symptoms., Conclusions: Our findings suggest that IgG-and IgG4-mediated food and yeast hypersensitivity in IBS is unlikely. IgG antibodies against food and yeast may reflect the diet.

Background: S100A12, a calcium-binding proinflammatory protein secreted by granulocytes, has been associated with different diseases of inflammatory origin, including inflammatory bowel disease (IBD). In this study, the utility of serum S100A12, in discriminating IBD from irritable bowel syndrome (IBS), was tested., Methods: S100A12 serum levels were determined in 64 patients with ulcerative colitis (UC), 64 with Crohn's disease (CD) and 73 with IBS, by means of an enzyme-linked immunosorbent assay. S100A12 serum levels were evaluated with respect to the levels of known inflammatory markers and patients' characteristics., Results: The median values of serum S100A12 levels were 68.2 ng/mL (range: 43.4-147.4) in UC, 70 ng/mL (41.4-169.8) in CD and 43.4 ng/mL (34.4-74.4) in IBS patients. UC and CD patients had significantly higher serum S100A12 levels compared to IBS patients (P = 0.001 for both comparisons). Moreover, a cut-off for serum S100A12 levels of 54.4 ng/mL could predict both UC and CD with a 66.7% sensitivity and a 64.4% specificity. The area under curve was estimated at 0.67 with a 95% confidence interval of 0.60-0.75 (P < 0.001). Considering standard activity indices, higher serum S100A12 levels in active compared to inactive IBD were observed, although the recorded difference did not reach statistical significance. C-reactive protein (CRP) and serum amyloid A (SAA) levels, showed a statistically significant positive correlation with S100A12 (r = 0.39, P = 0.001 and r = 0.23, P = 0.02 respectively)., Conclusions: Increased levels of circulating S100A12 are found in IBD, compared to IBS. When used to distinguish IBD from IBS adult patients, serum S100A12 levels exhibit moderate performance. On the other hand, serum S100A12 may serve as an inflammatory marker in IBD, since it is well correlated with CRP and SAA.

Background: Irritable bowel syndrome (IBS) is a common disorder that affects 10-15% of the population. Although characterised by a lack of reliable biological markers, the disease state is increasingly viewed as a disorder of the brain-gut axis. In particular, accumulating evidence points to the involvement of both the central and peripheral serotonergic systems in disease symptomatology. Furthermore, altered tryptophan metabolism and indoleamine 2,3-dioxygenase (IDO) activity are hallmarks of many stress-related disorders. The kynurenine pathway of tryptophan degradation may serve to link these findings to the low level immune activation recently described in IBS. In this study, we investigated tryptophan degradation in a male IBS cohort (n = 10) and control subjects (n = 26)., Methods: Plasma samples were obtained from patients and healthy controls. Tryptophan and its metabolites were measured by high performance liquid chromatography (HPLC) and neopterin, a sensitive marker of immune activation, was measured using a commercially available ELISA assay., Results: Both kynurenine levels and the kynurenine:tryptophan ratio were significantly increased in the IBS cohort compared with healthy controls. Neopterin was also increased in the IBS subjects and the concentration of the neuroprotective metabolite kynurenic acid was decreased, as was the kynurenic acid:kynurenine ratio., Conclusion: These findings suggest that the activity of IDO, the immunoresponsive enzyme which is responsible for the degradation of tryptophan along this pathway, is enhanced in IBS patients relative to controls. This study provides novel evidence for an immune-mediated degradation of tryptophan in a male IBS population and identifies the kynurenine pathway as a potential source of biomarkers in this debilitating condition.