Update on celiac disease

Single cell transcriptome sequencing indicates the cellular heterogeneity of small intestine tissue in celiac disease

Celiac disease (CeD) is an autoimmune small intestinal disease caused by gluten protein ingestion by genetically susceptible individuals. Genome-wide association studies and transcriptomic data have limited capacity to capture intercellular genetic variations. We aimed to construct a single cell transcriptome spectrum, analyze the immune microenvironment and cellular heterogeneity, discover disease-related specific genes and markers, and explore the pathogenesis of CeD. This study performed single cell RNA sequencing (scRNA-seq) on three small intestine biopsies from patients with CeD and three matched healthy Chinese controls. Immunohistochemistry (IHC) and quantitative polymerase chain reaction (qPCR) were used to validate potential diagnostic biomarkers of disease-differential genes. A total of 10 cell subpopulations were annotated, including three types of epithelial and stromal cells and seven types of immune cells. IHC revealed a pronounced overexpression of T cell disease-differential genes, TRAT1, BCL11B, and ETS1 in intraepithelial lymphocytes in the CeD group. Further clinical validation using qPCR confirmed that ETS1 (P = 0.010), TRAT1 (P < 0.001), and BCL11B (P = 0.036) were enriched in the CeD small intestinal tissue. The CD28/CTLA-4 pathway regulates the homeostasis of Treg cells. The IFITs family genes may serve as marker genes for antiviral specific CD4+ T cell subsets. CeD-derived subsets of CD8+ T cells frequently express genes associated with cytotoxicity, including IFNG, GZMK, GZMH, GZMB, SH2D1A, PRF1, and NKG7, as well as genes related to T cell exhaustion, such as PDCD10, CTLA4, TIGIT, PDCD1, and DUSP4. Inflammation and infection pathways were enriched in different cell populations. A single cell expression profile of CeD small intestinal tissue was successfully constructed using scRNA-seq in this study. New biomarkers for CeD-specific histopathology and potential therapeutic targets were discovered, and the biomarkers observed between inflammation and infection pathways were closely related to the onset of CeD.

Celiac Disease: An Academy of Nutrition and Dietetics Evidence-Based Nutrition Practice Guideline

Celiac disease is an autoimmune disorder in which the immune system of genetically susceptible individuals elicits a reaction to gluten causing small intestine damage. If left undiagnosed and untreated, the resulting nutrition malabsorption can lead to anemia, bone disease, growth faltering, or other consequences. The condition is lifelong and lacks a cure; the only treatment is lifelong adherence to a gluten-free diet (GFD). This diet is challenging to follow and adversely influences quality of life; however, it is essential to ensure intestinal recovery and prevent future negative health consequences. The Academy of Nutrition and Dietetics convened an expert panel complemented by a celiac disease patient advocate to evaluate evidence for six topics, including medical nutrition therapy; the GFD; oat consumption; micronutrients; pro-/prebiotics; and the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet. This publication outlines the Academy of Nutrition and Dietetics Evidence Analysis Library methods used to complete the systematic review and guideline development, and summarizes the recommendations and supporting evidence. The guidelines affirm that all individuals with celiac disease should follow a GFD (1C, Imperative) that may include gluten-free oats in adults (2D, Conditional). Children should follow a nutritionally adequate GFD that supports healthy growth and development (Consensus, Imperative) and does not unnecessarily restrict gluten-free oats (Consensus, Conditional). The guidelines indicate nutritional care should include routine nutritional assessment (Consensus, Imperative) and medical nutrition therapy (Consensus, Imperative). At this time, the guidelines do not support a recommendation for the addition of the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet (2C, Conditional); prebiotic or probiotic supplementation (2D, Conditional); or micronutrient supplementation (in the absence of nutritional deficiency) (Consensus, Conditional). The 2021 Celiac Disease Evidence-Based Nutrition Guideline will assist registered dietitian nutritionists in providing appropriate evidence-based medical nutrition therapy to support people with celiac disease in achieving and maintaining nutritional health and avoiding adverse celiac disease consequences throughout their lives.

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.

New-Level Insights into the Effects of Grape Seed Polyphenols on the Intestinal Processing and Transport of a Celiac Disease Immunodominant Peptide

The effect of three dietary tannins (procyanidin B3, B6, and T2) on the bioavailability of the 32-mer gliadin-derived immunogenic peptide was evaluated. An enterocyte-like Caco-2 cell line was used to mimic the epithelial transport of the 32-mer peptide, which was modeled by kinetic parameters with a mass spectrometry approach. The hydrolysis pattern on the enterocytes was analyzed, and the released peptides were quantified during the assay. The transport flux was dose-dependent. Along with procyanidin T2 and B6, procyanidin B3 promoted a significant inhibition mainly at the 100 μM peptide concentration. The hydrolysis efficiency was affected by procyanidins, while the cleavage pattern was suggested to be promoted by brush-border membranes at the apical compartment. The ability of procyanidins to molecularly bind to immunogenic peptides able to induce an adaptive response arose as a mechanism able to modulate their bioavailability, bioaccesibility, and further T CD4+ cell activation and expansion in a celiac disease (CD) model.

Evaluation of eye involvement in paediatric celiac disease patients

BACKGROUND

The non-classic presentation of paediatric celiac disease (CeD) becomes increasingly common in daily practice, which requires an awareness of eye findings. The purpose of this study was to evaluate eye involvement and effect of gluten-free diet on ocular involvement in paediatric CeD patients by measuring the thicknesses of choroid and ganglion cell complex (GCC) composed of retinal nerve fibre layer, ganglion cell layer and inner plexiform layer using enhanced depth imaging optical coherence tomography.

METHODS

Forty-three CeD patients aged between four and 16 years (mean age: 9.9 ± 4.1, 12 boys and 31 girls) and 48 healthy children (mean age: 11.3 ± 4.1,17 boys and 31 girls) were compared. Following comprehensive eye examinations, thicknesses of choroid at three points and GCC layers (retinal nerve fibre layer at five points, ganglion cell layer and inner plexiform layer) were obtained using enhanced depth imaging optical coherence tomography. Measurement of thicknesses of choroid and GCC layers by a trained optical coherence tomography technician and an ophthalmologist who were not aware about group of children in paediatric CeD patients with 1 year gluten-free diet was carried out.

RESULTS

All layers of subfoveal, nasal and temporal choroid were significantly thinner in CeD than in the control group (P < .001, all, respectively). No significant difference was observed between the CeD and control groups in terms of GCC thicknesses (P > .05, all, respectively).

CONCLUSION

Paediatric CeD caused thinning of subfoveal, nasal and temporal areas of choroid, and this change is apparent even after 1 year gluten-free diet. This eye involvement should be more closely screened at diagnosis, and long-term clinical results of thin choroid should be determined. Thicknesses of GCC layers were not different in CeD group and may reveal the effect of diet or not involvement.