HLA-Haplotypes Influence Microbiota Structure in Northwestern Mexican Schoolchildren Predisposed for Celiac Disease or Type 1 Diabetes.

To contribute to and elucidate the participation of microbiota in celiac disease (CD) and type 1 diabetes (T1D) development, we evaluated the influence of HLA haplotypes, familial risk, and diet on the microbiota of schoolchildren. We conducted a cross-sectional study on 821 apparently healthy schoolchildren, genotyping HLA DQ2/DQ8, and registering familial risk. We analyzed the fecal microbiota using 16S rRNA gene sequencing, and autoantibodies for CD or T1D by ELISA. After analyses, we created three groups: at-high-risk children (Group 1), at-high-risk children plus autoantibodies (Group 2), and nonrisk children (Group 3). HLA influenced the microbiota of Groups 1 and 2, decreasing phylogenetic diversity in comparison to Group 3. The relative abundance of Oscillospiraceae UCG_002, Parabacteroides, Akkermansia, and Alistipes was higher in Group 3 compared to Groups 1 and 2. Moreover, Oscillospiraceae UCG_002 and Parabacteroides were protectors of the autoantibodies' positivity (RRR = 0.441 and RRR = 0.034, respectively). Conversely, Agathobacter was higher in Group 2, and Lachnospiraceae was in both Groups 1 and 2. Lachnospiraceae correlated positively with the sucrose degradation pathway, while the principal genera in Group 3 were associated with amino acid biosynthesis pathways. In summary, HLA and familial risk influence microbiota composition and functionality in children predisposed to CD or T1D, increasing their autoimmunity risk.

Enteric parasitic infection disturbs bacterial structure in Mexican children with autoantibodies for type 1 diabetes and/or celiac disease.

BACKGROUND: Intestinal bacterial dysbiosis and increased gut permeability are associated with higher risk of developing type 1 diabetes (T1D) or celiac disease (CD). There is a lack of information on parasitism involved in gut disturbance of predisposed children. We evaluated the effect of enteropathogenic parasites (Cryptosporidium spp., Cyclospora spp. G. lamblia, and Blastocystis spp.) on the bacterial structure of feces from children with autoantibodies for T1D or CD. Participants included 37 children under 18 years of age, from whom stools were analyzed for enteric parasites by qPCR and 22/37 for bacterial profile by sequencing the V3-V4 region of the 16s rRNA gene. Dietary, clinical, and socioeconomic data was recorded. RESULTS: Pathogens parasitized 28/37 participants, Cryptosporidium spp. was the most prevalent (62.2%), followed by both Cyclospora cayetanensis and Blastocystis spp (37.8%). There were no dietary differences (p > 0.05) attributable to parasitism. Co-infected participants with Cryptosporidium and Cyclospora did not differ (p = 0.064) from non-infected participants in bacterial alpha phylogenetic diversity. The same parasites' co-infection was associated with a decreased abundance of the Ruminococaceae (p = 0.04) and Verrucomicrobioceae families, of the Akkermansia genus (p = 0.009). There was a lower Firmicutes/Bacteroidetes ratio (p = 0.02) in infected than in uninfected participants. CONCLUSIONS: Cryptosporidium and Cyclospora affected the bacterial structure at family and genus levels, decreasing the ratio between Firmicutes and Bacteroidetes in children with auto-antibodies for T1D or CD, which could increase the risk of illness onset.

Dietary Changes and Gut Dysbiosis in Children With Type 1 Diabetes.

OBJECTIVE: Gut dysbiosis in type 1 diabetes (T1D), characterized by high Bacteroides proportion, tends to reverse as T1D progresses, without reaching full recovery. Since diet influences microbiota structure, the aim was to evaluate the impact of dietary changes on Bacteroides proportion the first year of T1D evolution. METHODS: Dietary intake was assessed by 24-hour recalls and Bacteroides proportion by quantitative polymerase chain reaction, in 10 Mexican children (11.6 ± 1.92 years) with T1D at baseline and 3, 6 and 9 months' follow-up. Repeated measures analysis of variance and multiple linear regression were performed to compare ingested nutrients in relation with Bacteroides proportion. Effects over time were evaluated by mixed regression models. RESULTS: Patients with T1D decreased their energy (2621.89 to 1867.85 kcal, p = 0.028), protein (83.06 to 75.17 g, p = 0.012), and saturated fat consumption (40.83 to 25.23 g, p = 0.031) from baseline to 3 months, without posterior changes. Bacteroides proportion increased in the first months and tended to decrease at around 9 months (p > 0.05) and was positively correlated with saturated fat (ß = 3.70, p = 0.009) and total carbohydrates (ß = 0.73, p = 0.005) at 3 months. Carbohydrate consumption was related to decreased Bacteroides abundance over time (ß = -14.9, p = 0.004), after adjusting for glycosylated hemoglobin. CONCLUSIONS: Besides autoimmunity, diet appears to have a central role determining the T1D-associated dysbiosis evolution.

Old Fashioned vs. Ultra-Processed-Based Current Diets: Possible Implication in the Increased Susceptibility to Type 1 Diabetes and Celiac Disease in Childhood.

Ultra-processed foods are ready-to-heat and ready-to-eat products created to replace traditional homemade meals and dishes due to convenience and accessibility. Because of their low-fiber and high-fat and sugar composition, these foodstuffs could induce a negative impact on health. They are partially responsible for obesity and chronic non-transmissible diseases; additionally, they could impact in the prevalence of autoimmune diseases such as type 1 diabetes and celiac disease. The rationale is that the nutritional composition of ultra-processed foodstuffs can induce gut dysbiosis, promoting a pro-inflammatory response and consequently, a "leaky gut". These factors have been associated with increased risk of autoimmunity in genetically predisposed children. In addition, food emulsifiers, commonly used in ultra-processed products could modify the gut microbiota and intestinal permeability, which could increase the risk of autoimmunity. In contrast, unprocessed and minimally processed food-based diets have shown the capacity to promote gut microbiota eubiosis, anti-inflammatory response, and epithelial integrity, through bacterial butyrate production. Thus, to decrease the susceptibility to autoimmunity, genetically predisposed children should avoid ultra-processed food products and encourage the consumption of fresh and minimally processed foods.

Diabetogenic Potential of Ancestral and Modern Wheat Landraces.

Dear Editor, We read with interest the article by Gorelick et al. [1], who assayed the diabetogenic potential of two ancestral wheat landraces (Triticum turgidum ssp. dicoccoides and spp. dicoccum), compared to a modern wheat cultivar (T. aestivum) in NOD mice. [...].

Use of real-time polymerase chain reaction to identify Entamoeba histolytica in schoolchildren from northwest Mexico.

INTRODUCTION: Entamoeba histolytica, E. dispar, and E. moshkovskii are morphologically identical, but intestinal amebiasis is caused only by E. histolytica. Mexico is among the countries with high amebae infection rates, although the contribution of pathogenic amoeba to the total detected cases remains unknown, especially in the northwestern dry region. Therefore, the aim of this study was to identify the actual prevalence of E. histolytica using real-time polymerase chain reaction (PCR) in schoolchildren of  northwestern Mexico. METHODOLOGY: Participants were children from five public elementary schools in the low-socioeconomic-level suburban areas of Hermosillo, Sonora, Mexico. One stool sample was collected from each child and analyzed by the Faust technique for Entamoeba spp. and by real-time PCR for E. histolytica. RESULTS: Analysis of stool  samples from 273 children (9.0 ± 1.5 years of age) resulted in 25 (9.2%) positive for E. histolytica/E. dispar/E. moshkovskii by the Faust technique; of these, 3 were positive for E. histolytica by real-time PCR. In addition, 2 samples that were negative for E. histolytica/E. dispar/E. moshkovskii by the Faust technique were positive by real-time PCR. CONCLUSIONS: The actual prevalence of E. histolytica in our study population was 1.8%, which is lower than those reported in previous studies in other Mexican regions.

A population-wide applicable HLA-DQ2 and DQ8 genotyping using DNA from dried blood spots and duplex allele-specific qPCR amplification.

Genotyping of HLA-DQ2 and DQ8 haplotypes is important for diagnosis or for screening of early risk detection of celiac disease or type 1 diabetes. Usually, venous blood DNA extraction and expensive and time consuming amplification are used, that hinder population-wide studies. We assayed a friendly HLA-DQ2 and DQ8 genotyping procedure using a combination of DNA from dried blood spot (DBS) and duplex allele-specific qPCR amplification using SYBR Green. DNA was extracted using home-made buffers and compared to an extraction commercial kit. Duplex reactions by qPCR were designed using each Tm allele amplicon for reference samples (positive HLA-DQ2 or DQ8) with allele-specific primers. DBS samples from 558 children (7.99 ± 2.47 y) were collected. The DNA final yield obtained by the home-made extractive procedure was higher than from the commercial kit (1.11 ± 0.56 vs 0.23 ± 0.14 µg), while the quality was similar for both DNA samples. There was concordance in the amplification profiles for DNA samples obtained with both methods. All of four alleles from DQ2 and DQ8 haplotypes were accurately identified in duplex reactions. By using DBS samples and DNA extraction home-made procedure, the costs were reduced by 60%. The whole procedure is cost-effective for HLA-DQ2 and DQ8 genotyping.