Celiac disease diagnosis: transglutaminase, duodenal biopsy and genetic tests correlations.

Introduction: Celiac disease (CD) is an autoimmune enteropathy triggered by gluten ingestion in genetically susceptible individuals. The haplotypes HLA-DQ2 and DQ8, transglutaminase (TGA) antibodies, and biopsy findings are the main tests performed in the evaluation and CD diagnosis. The objective was to establish possible correlations between transglutaminase levels, genetic markers tests, and qualitative intestinal biopsy findings (modified Marsh classification) at the diagnosis. Methods: A retrospective cohort study. The selection criteria were confirmed CD cases with genetic tests performed. Statistical analysis was done mainly through One-way ANOVA, Kendall's correlation coefficient (T), and linear regression. Results: The study included 112 patients, with a mean age of 6 ± 4 years. All cases were tested to HLA-DQ2, and it was positive in 93%. HLA-DQ8 was tested in 73% of cases and it was positive in 61%. The percentage of negative genetic markers (DQ2/DQ8) was 4.5% for patients tested to both haplotypes. A comparison of DQ2/DQ8 (positive and negative) with clinical findings and tests performed did not identify any differences for most of the parameters analyzed. Cases of type I diabetes presented significant negative expression for DQ2(-); p = 0.05 and positive expression for DQ8(+); p = 0.023. The TGA antibody levels ranged from 18 to 36,745 U/ml. An inverse correlation was found between age and TGA-L level (p = 0.043). In 23% of the cases, the TGA levels were greater than 1,000 U/ml and presented a moderate positive correlation with the atrophy biopsy profile (T = 0.245). Patients with an atrophic biopsy profile (Marsh III) had a moderate positive correlation with growth failure (T = 0.218) but a negative correlation with constipation (T = -0.277). Conclusion: In terms of diagnosis tests for CD, transglutaminase levels and age presented an inverse correlation, with the level decreasing as age increased. A moderately positive correlation was found between mean transglutaminase with intestinal atrophy and growth retardation. The genetic test DQ2 was positive for 93% and negative genetic markers (DQ2/DQ8) represented 4.5% of cases studied.

Subchronic inhalation exposure to ultrafine particulate matter alters the intestinal microbiome in various mouse models.

Exposure to ultrafine particles (UFPs) has been associated with multiple adverse health effects. Inhaled UFPs could reach the gastrointestinal tract and influence the composition of the gut microbiome. We have previously shown that oral ingestion of UFPs alters the gut microbiome and promotes intestinal inflammation in hyperlipidemic Ldlr-/- mice. Particulate matter (PM)2.5 inhalation studies have also demonstrated microbiome shifts in normolipidemic C57BL/6 mice. However, it is not known whether changes in microbiome precede or follow inflammatory effects in the intestinal mucosa. We hypothesized that inhaled UFPs modulate the gut microbiome prior to the development of intestinal inflammation. We studied the effects of UFP inhalation on the gut microbiome and intestinal mucosa in two hyperlipidemic mouse models (ApoE-/- mice and Ldlr-/- mice) and normolipidemic C57BL/6 mice. Mice were exposed to PM in the ultrafine-size range by inhalation for 6 h a day, 3 times a week for 10 weeks at a concentration of 300-350 µg/m3.16S rRNA gene sequencing was performed to characterize sequential changes in the fecal microbiome during exposures, and changes in the intestinal microbiome at the end. PM exposure led to progressive differentiation of the microbiota over time, associated with increased fecal microbial richness and evenness, altered microbial composition, and differentially abundant microbes by week 10 depending on the mouse model. Cross-sectional analysis of the small intestinal microbiome at week 10 showed significant changes in α-diversity, ß-diversity, and abundances of individual microbial taxa in the two hyperlipidemic models. These alterations of the intestinal microbiome were not accompanied, and therefore could not be caused, by increased intestinal inflammation as determined by histological analysis of small and large intestine, cytokine gene expression, and levels of fecal lipocalin. In conclusion, 10-week inhalation exposures to UFPs induced taxonomic changes in the microbiome of various animal models in the absence of intestinal inflammation.

A novel probiotic, Lactobacillus johnsonii 456, resists acid and can persist in the human gut beyond the initial ingestion period.

Probiotics are considered to have multiple beneficial effects on the human gastrointestinal tract, including immunomodulation, pathogen inhibition, and improved host nutrient metabolism. However, extensive characterization of these properties is needed to define suitable clinical applications for probiotic candidates. Lactobacillus johnsonii 456 (LBJ 456) was previously demonstrated to have anti-inflammatory and anti-genotoxic effects in a mouse model. Here, we characterize its resistance to gastric and bile acids as well as its ability to inhibit gut pathogens and adhere to host mucosa. While bile resistance and in vitro host attachment properties of LBJ 456 were comparable to other tested probiotics, LBJ 456 maintained higher viability at lower pH conditions compared to other tested strains. LBJ 456 also altered pathogen adhesion to LS 174T monolayers and demonstrated contact-dependent and independent inhibition of pathogen growth. Genome analyses further revealed possible genetic elements involved in host attachment and pathogen inhibition. Importantly, we show that ingestion of Lactobacillus johnsonii 456 over a one week yogurt course leads to persistent viable bacteria detectable even beyond the period of initial ingestion, unlike many other previously described probiotic species of lactic acid bacteria.