Genetic and Environmental Contributors for Celiac Disease

Intestinal mRNA expression analysis of polarity-related genes identified the discriminatory ability of CRB3 as a diagnostic marker for celiac disease

BACKGROUND

Celiac disease (CD) is a chronic autoimmune disorder characterized by an abnormal immune response to gluten, a protein found in wheat, barley, and rye. It is well established that the integrity of epithelial tight junctions (TJs) and adherens junctions (AJs) plays a crucial role in the pathogenesis of CD. These junctional complexes contribute to the apical-basal polarity of the intestinal epithelial cells, which is crucial for their proper functioning.

METHODS

Sixty CD subjects, and 50 controls were enrolled in the current study. Mucosal samples were obtained from the distal duodenum, total RNA was extracted and complementary DNA was synthesized. The relative expression levels of the desired genes were evaluated by quantitative real-time polymerase chain reaction based on ΔΔCt method. The gene-gene interaction network was also constructed using GeneMANIA.

RESULTS

CRB3 (p = .0005), LKB1 (p < .0001), and SCRIB (p = .0005) had lower expression in CD patients compared to controls, while PRKCZ expression did not differ between groups (p > .05). CRB3 represented a significant diagnostic value for differentiating CD patients from the control group (p = .02).

CONCLUSION

The aim of the current study was to evaluate the changes in the mRNA expression levels of SCRIB, PRKCZ, LKB1, and CRB3 genes in the small intestinal biopsy samples of CD patients in comparison to the healthy control subjects. Our data uncover the importance of polarity-related genes (especially CRB3) in CD pahtomechanism, that may facilitate the planning of the future studies looking for finding innovative diagnostic and therapeutic strategies for CD.

Genome-Wide Association Studies of Diarrhea Frequency and Duration in the First Year of Life in Bangladeshi Infants

BACKGROUND

Diarrhea is the second leading cause of death in children under 5 years old worldwide. Known diarrhea risk factors include sanitation, water sources, and pathogens but do not fully explain the heterogeneity in frequency and duration of diarrhea in young children. We evaluated the role of host genetics in diarrhea.

METHODS

Using 3 well-characterized birth cohorts from an impoverished area of Dhaka, Bangladesh, we compared infants with no diarrhea in the first year of life to those with an abundance, measured by either frequency or duration. We performed a genome-wide association analysis for each cohort under an additive model and then meta-analyzed across the studies.

RESULTS

For diarrhea frequency, we identified 2 genome-wide significant loci associated with not having any diarrhea, on chromosome 21 within the noncoding RNA AP000959 (C allele odds ratio [OR] = 0.31, P = 4.01 × 10-8), and on chromosome 8 within SAMD12 (T allele OR = 0.35, P = 4.74 × 10-7). For duration of diarrhea, we identified 2 loci associated with no diarrhea, including the same locus on chromosome 21 (C allele OR = 0.31, P = 1.59 × 10-8) and another locus on chromosome 17 near WSCD1 (C allele OR = 0.35, P = 1.09 × 10-7).

CONCLUSIONS

These loci are in or near genes involved in enteric nervous system development and intestinal inflammation and may be potential targets for diarrhea therapeutics.

Characteristics of gut microbiota and fecal metabolomes in patients with celiac disease in Northwest China

Celiac disease (CD) is an autoimmune small bowel disease. The pattern of gut microbiota is closely related to dietary habits, genetic background, and geographical factors. There is a lack of research on CD-related gut microbiota in China. This study aimed to use 16S rDNA sequencing and metabolomics to analyze the fecal microbial composition and metabolome characteristics in patients diagnosed with CD in Northwest China, and to screen potential biomarkers that could be used for its diagnosis. A significant difference in the gut microbiota composition was observed between the CD and healthy controls groups. At the genus level, the abundance of Streptococcus, Lactobacillus, Veillonella, and Allisonella communities in the CD group were increased (Q < 0.05). Furthermore, the abundance of Ruminococcus, Faecalibacterium, Blautia, Gemmiger, and Anaerostipes community in this group were decreased (Q < 0.05). A total of 222 different fecal metabolites were identified in the two groups, suggesting that CD patients have a one-carbon metabolism defect. Four species of bacteria and six metabolites were selected as potential biomarkers using a random forest model. Correlation analysis showed that changes in the gut microbiota were significantly correlated with changes in fecal metabolite levels. In conclusion, the patterns of distribution of gut microbiota and metabolomics in patients with CD in Northwest China were found to be unique to these individuals. This has opened up a new way to explore potential beneficial effects of supplementing specific nutrients and potential diagnostic and therapeutic targets in the future.

HLA-DQ genotype distribution and risk evaluation of celiac disease in Northwest China

BACKGROUND

Celiac disease (CD) is an autoimmune small bowel disease. Genetic susceptibility for CD is mainly determined by the human leukocyte antigen (HLA)-DQ haplotypes. The risk of CD conferred by HLA genotypes varies geographically and across populations, however, this has not yet been documented in Chinese patients with CD.

AIMS

To investigate the distribution of HLA-DQ and the related risks of CD development in Northwest China.

METHODS

A total of 75 CD patients and 300 healthy individuals were genotyped for HLA-DQ using the Illumina NextSeq, and the relative risks of the different genotypes were evaluated.

RESULTS

In total, 68.00% of CD patients and 21.00% of controls carried HLA-DQ2.5 heterodimers (p < 0.001). We identified four CD risk gradients. Individuals carrying a double dose of DQB1*02 had the highest risk of developing CD (1:16); however, with heterozygosis (DQB1*02:02/DQB1*02:01) having the highest risk (1:9). HLA-DQ2.5 individuals with a single copy of HLA-DQB1*02, in either the cis or trans configuration, were at a medium risk (1:38). Non-DQ2.5 carriers of DQ8 or DQ2.2 were at low risk, while only carriers of DQ7.5 or DQX.5 were at very low risk. Patients with the HLA-DQ2.5 genotype had more severe mucosal damage compared with the HLA-DQ2.5 genotype negative CD patients (70.59% vs. 41.67%, p = 0.016).

CONCLUSION

Genetic susceptibility to CD is highly prevalent in the Northwest Chinese population and the highest risk of developing CD was associated with the DQ2.5/DQ2.2 genotype. The DQ2.5 allele is involved in the severity of mucosal injury.

Microbiota profile of new-onset celiac disease in children in Saudi Arabia

Background

Intestinal dysbiosis has been reported to be associated with celiac disease (CeD) in Western populations but little is known in other populations who have different dietary lifestyle and genetic background. The purpose of this study was to determine whether a different microbiota profile is associated with CeD in children in Saudi Arabia.

Results

Forty children with CeD, 20 healthy controls, and 19 non-CeD controls were enrolled. The median age at diagnosis was 10.3, 11.3 and 10.6 years in children with CeD, fecal, and mucosal control groups, respectively. Significant differences in microbial composition between children with CeD and controls both at fecal and mucosal level were identified. Fecal samples were more diverse and richer in bacteria as compared with mucosal samples. Proteobacteria were more abundant in duodenal mucosal samples and Firmicutes and Bacteroides were more abundant in stools. The abundance of many taxa was significantly different between children with CeD and non-CeD controls. In mucosal samples, Bifidobacterium angulatum (unadjusted p = 0.006) and Roseburia intestinalis (unadjusted p = 0.031) were examples of most significantly increased species in children with CeD and non-CeD controls, respectively. In fecal samples, there were 169 bacterial species with significantly different abundance between children with CeD and non- CeD controls.

Conclusions

To our knowledge, this is the first report on the microbial profile in a non-Western population of children with new onset CeD. The fact that mucosal and fecal samples were collected from newly diagnosed children with CeD on normal gluten-containing diet suggests strong association between the identified bacteria and CeD. The identification of many unreported bacterial species significantly associated with CeD, indicates the need for further studies from different populations to expand our understanding of the role of bacteria in the pathogenesis of CeD, hopefully leading to the discovery of new adjuvant treatment options.

Clinical presentation, biochemical profile, and HLA haplotype frequency of celiac disease among adults in Northwest China

OBJECTIVE

To evaluate the clinical characteristics, biochemical parameters and the distribution of HLA-DQ genotypes among adult patients with celiac disease (CD) in Northwest China.

METHODS

This cross-sectional study retrospectively collected clinical, biochemical, and HLA-DQ genotype of patients with CD from a tertiary hospital in Xinjiang Uygur Autonomous Region, China between March 2016 and December 2021. Small intestinal biopsy and serum-specific antibodies were used to diagnose CD.

RESULTS

Of the 102 CD patients, 63.7% were women (female: male = 1.76:1), and the mean age was 47.3 ± 14.7 years at diagnosis. Common gastrointestinal symptoms included abdominal pain (50.0%), diarrhea (39.2%), and abdominal distension (24.5%). While common extraintestinal manifestations were anemia (48.0%), osteopenia or osteoporosis (36.3%), and fatigue (35.3%). Approximately 34.3% of patients with CD had comorbidities, with the most common being thyroid diseases (18.6%). Biochemical profiles showed lower hemoglobin, higher platelet count, and 25-hydroxyvitamin D (25[OH]D) deficiency. HLA-DQ2/DQ8 was detected among all 53 patients who underwent genotype testing; the frequency of the HLA-DQ2.5, DQ2.2, and DQ8 haplotypes was 71.7%, 24.5%, and 3.8%, respectively.

CONCLUSIONS

CD was more common among women. Clinical manifestations include primarily gastrointestinal symptoms, but extraintestinal manifestations were not uncommon. Lower hemoglobin level, higher platelet count, and 25[OH]D deficiency are the main biochemical manifestations. The HLA-DQ2.5 and DQ2.2 haplotypes are the most common genotypes in CD.

How does a celiac iceberg really float? The relationship between celiac disease and gluten

Celiac disease (CD) is an autoimmune intestinal disease caused by intolerance of genetically susceptible individuals after intake of gluten-containing grains (including wheat, barley, etc.) and their products. Currently, CD, with "iceberg" characteristics, affects a large population and is distributed over a wide range of individuals. This present review summarizes the latest research progress on the relationship between CD and gluten. Furthermore, the structure and function of gluten peptides related to CD, gluten detection methods, the effects of processing on gluten and gluten-free diets are emphatically reviewed. In addition, the current limitations in CD research are also discussed. The present work facilitates a comprehensive understanding of CD as well as gluten, which can provide a theoretical reference for future research.

Baseline Fecal Microbiota in Pediatric Patients With Celiac Disease Is Similar to Controls But Dissimilar After 1 Year on the Gluten-Free Diet

The objectives of this pilot study were to examine fecal microbiota composition of pediatric patients with celiac disease (CD) before and after a 1-year gluten-free diet (GFD) and to determine the association with symptoms and anti-tissue transglutaminase (aTTG) antibody.

Methods

Stool samples were obtained from pediatric patients with CD and from healthy controls. Patients were classified by the presence (diarrhea, abdominal pain, weight loss) or absence (asymptomatic, headache, fatigue, etc.) of typical CD gastrointestinal symptoms and by aTTG normalization post-GFD intervention (< 7 U/mL). Fecal microbial composition was measured using 16S ribosomal RNA gene amplicon sequencing of the V3-V4 region.

Results

At diagnosis, 13 of 22 patients with CD had typical gastrointestinal symptoms, the remaining patients having atypical or asymptomatic presentations. After a 1-year GFD, all symptomatic patients improved and 9 of 19 had normalized aTTG. Prior to GFD, no distinct microbial signature was observed between patients and controls (P = 0.39). Post-GFD, patients with CD had a unique microbial signature with reductions in known fiber-degrading bacteria, including Blautia, Dorea, Lactobacillus, and Prevotella compared with controls. Within the patients with CD, microbial composition was not associated with reported symptom presentation or aTTG normalization.

Conclusions

Pediatric patients with CD only had a unique microbial signature compared with healthy controls when placed on the GFD. These results suggest that pediatric patients with CD may not have a unique fecal microbial signature indicative of inherent dysbiosis, in contrast to that suggested for older patients. In children with CD, diet may play a role in shaping microbial composition more so than disease status.

Clinical guidelines “Chronic diarrhea in adults”

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Gastrointestinal dysfunction in neuroinflammatory diseases: Multiple sclerosis, neuromyelitis optica, acute autonomic ganglionopathy and related conditions

Disorders of the nervous system can produce a variety of gastrointestinal (GI) dysfunctions. Among these, lesions in various brain structures can cause appetite loss (hypothalamus), decreased peristalsis (presumably the basal ganglia, pontine defecation center/Barrington's nucleus), decreased abdominal strain (presumably parabrachial nucleus/Kolliker-Fuse nucleus) and hiccupping and vomiting (area postrema/dorsal vagal complex). In addition, decreased peristalsis with/without loss of bowel sensation can be caused by lesions of the spinal long tracts and the intermediolateral nucleus or of the peripheral nerves and myenteric plexus. Recently, neural diseases of inflammatory etiology, particularly those affecting the PNS, are being recognized to contribute to GI dysfunction. Here, we review neuroinflammatory diseases that potentially cause GI dysfunction. Among such CNS diseases are multiple sclerosis, neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein associated disorder, and autoimmune encephalitis. Peripheral nervous system diseases impacting the gut include Guillain-Barre syndrome, chronic inflammatory demyelinating polyneuropathy, acute sensory-autonomic neuropathy/acute motor-sensory-autonomic neuropathy, acute autonomic ganglionopathy, myasthenia gravis and acute autonomic neuropathy with paraneoplastic syndrome. Finally, collagen diseases, such as Sjogren syndrome and systemic sclerosis, and celiac disease affect both CNS and PNS. These neuro-associated GI dysfunctions may predate or present concurrently with brain, spinal cord or peripheral nerve dysfunction. Such patients may visit gastroenterologists or physicians first, before the neurological diagnosis is made. Therefore, awareness of these phenomena among general practitioners and collaboration between gastroenterologists and neurologists are highly recommended in order for their early diagnosis and optimal management, as well as for systematic documentation of their presentations and treatment.

Contribution of Infectious Agents to the Development of Celiac Disease

The ingestion of wheat gliadin (alcohol-soluble proteins, an integral part of wheat gluten) and related proteins induce, in genetically predisposed individuals, celiac disease (CD), which is characterized by immune-mediated impairment of the small intestinal mucosa. The lifelong omission of gluten and related grain proteins, i.e., a gluten-free diet (GFD), is at present the only therapy for CD. Although a GFD usually reduces CD symptoms, it does not entirely restore the small intestinal mucosa to a fully healthy state. Recently, the participation of microbial components in pathogenetic mechanisms of celiac disease was suggested. The present review provides information on infectious diseases associated with CD and the putative role of infections in CD development. Moreover, the involvement of the microbiota as a factor contributing to pathological changes in the intestine is discussed. Attention is paid to the mechanisms by which microbes and their components affect mucosal immunity, including tolerance to food antigens. Modulation of microbiota composition and function and the potential beneficial effects of probiotics in celiac disease are discussed.

The Role of Cannabinoid Receptor Type 2 in the Bone Loss Associated With Pediatric Celiac Disease

OBJECTIVES

In this study, we investigated the role of the cannabinoid receptor type 2 (CB2) in the bone loss associated with celiac disease (CD) evaluating the effect of its pharmacological modulation on osteoclast activity. We previously demonstrated a significant association between the CB2 Q63R variant and CD, suggesting it as a possible disease biomarker. Moreover, CB2 stimulation is beneficial for reducing osteoclast activity in several bone pathologic conditions.

METHODS

In vitro osteoclasts (OCs) were differentiated from peripheral blood mononuclear cells of healthy donors, CD children at diagnosis and after 1 year of gluten-free diet (GFD) and characterized by real-time PCR and western blot for the expression of CB2 and specific osteoclastic markers, TRAP and Cathepsin K. TRAP assay and Bone Resorption assay were performed to evaluate osteoclast activity before and after 48 h exposure to CB2 selective drugs (JWH-133 and AM630) and Vitamin D.

RESULTS

We found in CD patients an osteoclast hyperactivation and low levels of CB2. CB2 stimulation with JWH-133 agonist is more effective than Vitamin D in reducing osteoclast activity whereas CB2 blockade with AM630 increases osteoclast activation. The anti-osteoporotic effect of JWH-133 decreases when used in co-treatment with vitamin D. GFD reduces osteoclast activity without restore CB2 expression.

CONCLUSIONS

CB2 could be a molecular marker to predict the risk of bone alterations in CD and a pharmacological target to reduce bone mass loss in patients who need a direct intervention on bone metabolism, in addition to the GFD.

Exploring celiac disease candidate pathways by global gene expression profiling and gene network cluster analysis

Celiac disease (CeD) is a gastrointestinal autoimmune disorder, whose specific molecular basis is not yet fully interpreted. Therefore, in this study, we compared the global gene expression profile of duodenum tissues from CeD patients, both at the time of disease diagnosis and after two years of the gluten-free diet. A series of advanced systems biology approaches like differential gene expression, protein–protein interactions, gene network-cluster analysis were deployed to annotate the candidate pathways relevant to CeD pathogenesis. The duodenum tissues from CeD patients revealed the differential expression of 106 up- and 193 down-regulated genes. The pathway enrichment of differentially expressed genes (DEGs) highlights the involvement of biological pathways related to loss of cell division regulation (cell cycle, p53 signalling pathway), immune system processes (NOD-like receptor signalling pathway, Th1, and Th2 cell differentiation, IL-17 signalling pathway) and impaired metabolism and absorption (mineral and vitamin absorptions and drug metabolism) in celiac disease. The molecular dysfunctions of these 3 biological events tend to increase the number of intraepithelial lymphocytes (IELs) and villous atrophy of the duodenal mucosa promoting the development of CeD. For the first time, this study highlights the involvement of aberrant cell division, immune system, absorption, and metabolism pathways in CeD pathophysiology and presents potential novel therapeutic opportunities.

Celiac Disease and Non-celiac Wheat Sensitivity: State of Art of Non-dietary Therapies

Gluten related disorders (GRD), which include celiac disease, non-celiac wheat sensitivity and wheat allergy are heterogeneous conditions triggered by ingestion of gluten-containing grains. Together, their prevalence is estimated to be ~5% in the general population, however, in the last years the number of diagnoses has been rapidly increasing. To this day, the gold standard treatment for these disorders is the complete removal of gluten-containing grains from the diet. Although this therapy results effective in the majority of patients, up to 30% of individuals affected by GRD continue to present persistent symptoms. In addition, gluten-free diet has been shown to have poor nutritional quality and to cause a socio-economic burden in patients' quality of life. In order to respond to these issues, the scientific community has been focusing on finding additional and adjuvant non-dietary therapies. In this review, we focus on two main gluten related disorders, celiac disease and non-celiac wheat sensitivity. We delineate the actual knowledge about potential treatments and their relative efficacy in pre-clinical and clinical trials.

Psychometric properties of the Persian version of the celiac disease adherence test questionnaire

BACKGROUND

A gluten-free diet (GFD) is the only effective treatment for celiac patients and assessing adherence to this diet is important. Celiac disease Adherence Test (CDAT) is a valid English-language questionnaire that is used for assessing the adherence to the GFD. In the present study, we aimed to translate the CDAT questionnaire in Persian and evaluate its validity and reliability.

METHODS

In the present cross-sectional study, CDAT was translated and back-translated by three bilingual professional translators. Content validity was evaluated by 12 gastroenterologists and nutritionists. To assess the construct validity, 230 patients with celiac disease were randomly selected from the national celiac disease registry database. Internal consistency of the items and test-retest reliability were assessed by Cronbach's alpha and Intraclass Correlation Coefficient (ICC). To assess the convergent validity of the questionnaire, the correlation coefficient between the CDAT score and anti-tissue transglutaminase immunoglobulin A (anti-t-TG-IgA) titer was assessed.

RESULTS

The content validity index, content validity ratio, and impact score of the Persian version of CDAT (Pv-CDAT) were 0.97, 0.95, and 4.61 respectively. Three significant factors were extracted and according to the confirmatory factor analysis the three-factor model had adequate fitness (chi-square p-value of 0.74, root mean error of approximation: 0.001 [95% CI: 0.001-0.083], comparative fit index: 1, standardized root mean squared residual: 0.04, and coefficient of determination: 0.78). The questionnaire had good feasibility with the floor effect of 3.1% and the ceiling effect of 0.4%. Moreover, it has high internal consistency (Cronbach-alpha: 0.71) and test-retest reliability (ICC: 0.78). The correlations between CDAT categories and anti-tTG-IgA categories showed a significant correlation between the two tests (r = 0.53; P < 0.001).

CONCLUSIONS

The results of the present study showed that the Pv-CDAT questionnaire with high validity, reliability, and internal consistency can be used for assessing adherence to the GFD in adult celiac patients in Iran.