Predictors of adherence to a gluten-free diet in celiac disease: Do knowledge, attitudes, experiences, symptoms, and quality of life play a role?

OBJECTIVES: This study aimed to identify the relationship between adherence to a gluten-free diet (GFD) and demographic characteristics, knowledge, attitudes, and beliefs regarding celiac disease (CD) and GFD, experiences of following a GFD, symptoms, and quality of life (QoL). METHODS: Patients with CD were recruited from outpatient clinics. Adherence to GFD was assessed using the CD adherence test (CDAT) and GFD score (GFD-S). Knowledge, attitudes, experiences, symptoms, and QoL were assessed using existing questionnaires. A multivariate logistic regression was performed. RESULTS: Overall, 116 patients with CD were included (48 ± 16 y; 70% female). Based on the CDAT, 58 patients (50%) were adequate adherers, but 86 patients (74%) were adequate adherers according to GFD-S. When adherence was measured using the CDAT, being female was associated with lower odds of adherence (odds ratio [OR]: 0.36; P = 0.028), and better emotional wellbeing was associated with higher odds of adherence (OR: 1.19; P < 0.001). When adherence was measured using GFD-S, membership in a support group (OR: 6.17; P = 0.002), stronger beliefs about the chronicity of CD (OR: 1.15; P = 0.059), and weaker beliefs on accident/chance causing CD (OR: 1.94; P = 0.05) were associated with greater odds of adherence. Difficulties when eating with family/friends (OR: 0.98; P = 0.005) and weaker beliefs on immunity causing CD (OR: 0.77; P = 0.031) were associated with lower odds of adherence. CONCLUSIONS: The association between gender, attending support groups, attitudes, experiences, and QoL with adherence to a GFD should be considered by health care professionals managing patients with CD.

Recent Progress and Recommendations on Celiac Disease From the Working Group on Prolamin Analysis and Toxicity.

Celiac disease (CD) affects a growing number of individuals worldwide. To elucidate the causes for this increase, future multidisciplinary collaboration is key to understanding the interactions between immunoreactive components in gluten-containing cereals and the human gastrointestinal tract and immune system and to devise strategies for CD prevention and treatment beyond the gluten-free diet. During the last meetings, the Working Group on Prolamin Analysis and Toxicity (Prolamin Working Group, PWG) discussed recent progress in the field together with key stakeholders from celiac disease societies, academia, industry and regulatory bodies. Based on the current state of knowledge, this perspective from the PWG members provides recommendations regarding clinical, analytical and legal aspects of CD. The selected key topics that require future multidisciplinary collaborative efforts in the clinical field are to collect robust data on the increasing prevalence of CD, to evaluate what is special about gluten-specific T cells, to study their kinetics and transcriptomics and to put some attention to the identification of the environmental agents that facilitate the breaking of tolerance to gluten. In the field of gluten analysis, the key topics are the precise assessment of gluten immunoreactive components in wheat, rye and barley to understand how these are affected by genetic and environmental factors, the comparison of different methods for compliance monitoring of gluten-free products and the development of improved reference materials for gluten analysis.

Natural variants of α-gliadin peptides within wheat proteins with reduced toxicity in coeliac disease.

The only generally accepted treatment of coeliac disease (CD) is a lifelong gluten-free diet. Wheat gluten proteins include gliadins, low and high molecular weight glutenins. However, we have found significant structural variations within these protein families among different cultivars. To determine which structural motifs might be less toxic than others, we assessed five variants of α-gliadin immunodominant CD-toxic peptides synthesised as 16mers in CD T cell stimulation assays with gluten-sensitive T cell lines generated from duodenal biopsies from CD-affected individuals. The peptides harboured the overlapping T cell epitopes DQ 2.5-glia-α-2 and naturally occurring variants that differed in certain amino acids (AA). The results revealed that introduction of two selected AA substitutions in α-gliadin peptides reduced immunogenicity. A peptide with three AA substitutions involving two glutamic acids (E) and one glutamine residue (G) revealed the peptide was negative in 5:5 samples. We used CD small-intestinal organ culture to assess CD toxicity that revealed two peptides with selected substitution of both glutamic acid (E) and proline (P) residues abrogated evidence of CD toxicity.

Diagnostic and Research Aspects of Small Intestinal Disaccharidases in Coeliac Disease.

Disaccharidases (DS) are brush border enzymes embedded in the microvillous membrane of small intestinal enterocytes. In untreated coeliac disease (CD), a general decrease of DS activities is seen. This manuscript reviews different aspects of DS activities in CD: their utility in the diagnosis and their application to in vitro toxicity testing. The latter has never been established in CD research. However, with the recent advances in small intestinal organoid techniques, DS might be employed as a biomarker for in vitro studies. This includes establishment of self-renewing epithelial cells raised from tissue, which express differentiation markers, including the brush border enzymes. Determining duodenal DS activities may provide additional information during the diagnostic workup of CD: (i) quantify the severity of the observed histological lesions, (ii) provide predictive values for the grade of mucosal villous atrophy, and (iii) aid diagnosing CD where minor histological changes are seen. DS can also provide additional information to assess the response to a gluten-free diet as marked increase of their activities occurs four weeks after commencing it. Various endogenous and exogenous factors affecting DS might also be relevant when considering investigating the role of DS in other conditions including noncoeliac gluten sensitivity and DS deficiencies.

Approach to patients with refractory coeliac disease.

Refractory coeliac disease (RCD) is a recognised complication, albeit very rare, of coeliac disease (CD). This condition is described when individuals with CD continue to experience enteropathy and subsequent or ongoing malabsorption despite strict adherence to a diet devoid of gluten for at least 12 months and when all other causes mimicking this condition are excluded. Depending on the T-cell morphology and T-cell receptor (TCR) clonality at the ß/γ loci, RCD can be subdivided into type 1 (normal intra-epithelial lymphocyte morphology, polyclonal TCR population) and type 2 (aberrant IELs with clonal TCR). It is important to differentiate between the two types as type 1 has an 80% survival rate and is managed with strict nutritional and pharmacological management. RCD type 2 on the other hand has a 5-year mortality of 50% and can be complicated by ulcerative jejunitis or enteropathy-associated T-cell lymphoma (EATL). Management of RCD type 2 has challenged many experts, and different treatment approaches have been adopted with variable results. Some of these treatments include immunomodulation with azathioprine and steroids, methotrexate, cyclosporine, alemtuzumab (an anti CD-52 monoclonal antibody), and cladribine or fludarabine sometimes with autologous stem cell transplantation. In this article, we summarise the management approach to patients with RCD type 2.

Coeliac disease: immunogenicity studies of barley hordein and rye secalin-derived peptides.

Coeliac disease (CD) is an inflammatory disorder of the small intestine. It includes aberrant adaptive immunity with presentation of CD toxic gluten peptides by HLA-DQ2 or DQ8 molecules to gluten-sensitive T cells. A ω-gliadin/C-hordein peptide (QPFPQPEQPFPW) and a rye-derived secalin peptide (QPFPQPQQPIPQ) were proposed to be toxic in CD, as they yielded positive responses when assessed with peripheral blood T-cell clones derived from individuals with CD. We sought to assess the immunogenicity of the candidate peptides using gluten-sensitive T-cell lines obtained from CD small intestinal biopsies. We also sought to investigate the potential cross-reactivity of wheat gluten-sensitive T-cell lines with peptic-tryptic digested barley hordein (PTH) and rye secalin (PTS). Synthesised candidate peptides were deamidated with tissue transglutaminase (tTG). Gluten-sensitive T-cell lines were generated by culturing small intestinal biopsies from CD patients with peptic-tryptic gluten (PTG), PTH or PTS, along with autologous PBMCs for antigen presentation. The stimulation indices were determined by measuring the relative cellular proliferation via incorporation of 3 H-thymidine. The majority of T-cell lines reacted to the peptides studied. There was also cross-reactivity between wheat gluten-sensitive T-cell lines and the hordein, gliadin and secalin peptides. PTH, PTS, barley hordein and rye secalin-derived CD antigen-sensitive T-cell lines showed positive stimulation with PTG. ω-gliadin/C-hordein peptide and rye-derived peptide are immunogenic to gluten-sensitive T-cell lines and potentially present in wheat, rye and barley. Additional CD toxic peptides may be shared.

Tight junctions in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer.

Inflammatory bowel diseases are characterised by inflammation that compromises the integrity of the epithelial barrier. The intestinal epithelium is not only a static barrier but has evolved complex mechanisms to control and regulate bacterial interactions with the mucosal surface. Apical tight junction proteins are critical in the maintenance of epithelial barrier function and control of paracellular permeability. The characterisation of alterations in tight junction proteins as key players in epithelial barrier function in inflammatory bowel diseases is rapidly enhancing our understanding of critical mechanisms in disease pathogenesis as well as novel therapeutic opportunities. Here we give an overview of recent literature focusing on the role of tight junction proteins, in particular claudins, in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer.

Identification of coeliac disease triggering glutenin peptides in adults.

OBJECTIVE: Coeliac disease affects approximately 1% of Northern American and European populations. It is caused by an inappropriate immune response to dietary gluten. Gluten comprises of two major protein fractions: gliadins and glutenins. Glutenins have recently been found to be toxic to coeliac individuals. Proliferation assays suggest in some but not all paediatric coeliac individuals there may be immunological stimulation with high molecular weight (HMW) glutenins. Less evidence pertains to low molecular weight (LMW) glutenins. The aim is to assess adaptive, T-cell driven, and innate immune response in adult coeliac individuals towards HMW glutenin peptide, glut04, and LMW glutenin peptide, glt156. MATERIALS AND METHODS: Coeliac patients were recruited attending endoscopy for routine monitoring. Adaptive immune response towards glut04 and glt156 was measured by proliferation assays and measurement of interferon-γ secretion in 28 T-cell lines. The innate immune response was assessed by measurement of enterocyte cell height (ECH) in coeliac small intestinal biopsies following overnight incubation in organ culture chambers in a further nine individuals. RESULTS: There were 3/28 and 2/28 positive proliferation results using gluten-sensitive T-cells with glut04 and glt156, respectively. All coeliac biopsies tested in organ culture chambers demonstrated clear reduction in ECH with peptic-tryptic digest of whole industrial gluten, glut04 and glt156 when compared to negative control ovalbumin (p < 0.005). Three individuals had both T-cell and organ culture study data. Their proliferation assays showed no stimulation of the T-cells. CONCLUSIONS: This study demonstrates glutenin epitopes glut04 and glt156, while minor T-cell epitopes, are important in their ability to trigger the innate immune response.

Identification and molecular characterization of oat peptides implicated on coeliac immune response.

BACKGROUND: Oats provide important nutritional and pharmacological properties, although their safety in coeliac patients remains controversial. Previous studies have confirmed that the reactivity of the anti-33-mer monoclonal antibody with different oat varieties is proportional to the immune responses in terms of T-cell proliferation. Although the impact of these varieties on the adaptive response has been studied, the role of the dendritic cells (DC) is still poorly understood. The aim of this study is to characterize different oat fractions and to study their effect on DC from coeliac patients. METHODS AND RESULTS: Protein fractions were isolated from oat grains and analyzed by SDS-PAGE. Several proteins were characterized in the prolamin fraction using immunological and proteomic tools, and by Nano-LC-MS/MS. These proteins, analogous to α- and γ-gliadin-like, showed reactive sequences to anti-33-mer antibody suggesting their immunogenic potential. That was further confirmed as some of the newly identified oat peptides had a differential stimulatory capacity on circulating DC from coeliac patients compared with healthy controls. CONCLUSIONS: This is the first time, to our knowledge, where newly identified oat peptides have been shown to elicit a differential stimulatory capacity on circulating DC obtained from coeliac patients, potentially identifying immunogenic properties of these oat peptides.

Recognising and Managing Refractory Coeliac Disease: A Tertiary Centre Experience.

Refractory coeliac disease (RCD) is a rare complication of coeliac disease (CD) and involves malabsorption and villous atrophy despite adherence to a strict gluten-free diet (GFD) for at least 12 months in the absence of another cause. RCD is classified based on the T-cells in the intra-epithelial lymphocyte (IEL) morphology into type 1 with normal IEL and type 2 with aberrant IEL (clonal) by PCR (polymerase chain reaction) for T cell receptors (TCR) at the ß/γ loci. RCD type 1 is managed with strict nutritional and pharmacological management. RCD type 2 can be complicated by ulcerative jejunitis or enteropathy associated lymphoma (EATL), the latter having a five-year mortality of 50%. Management options for RCD type 2 and response to treatment differs across centres and there have been debates over the best treatment option. Treatment options that have been used include azathioprine and steroids, methotrexate, cyclosporine, campath (an anti CD-52 monoclonal antibody), and cladribine or fluadribine with or without autologous stem cell transplantation. We present a tertiary centre's experience in the treatment of RCD type 2 where treatment with prednisolone and azathioprine was used, and our results show good response with histological recovery in 56.6% of treated individuals.

Support for patients with celiac disease: A literature review.

BACKGROUND: Celiac disease (CD) is a lifelong disorder. Patients are at increased risk of complications and comorbidity. OBJECTIVES: We conducted a review of the literature on patient support and information in CD and aim to issue recommendations about patient information with regards to CD. DATA SOURCE: We searched PubMed for English-language articles published between 1900 and June 2014, containing terms related to costs, economics of CD, or education and CD. STUDY SELECTION: Papers deemed relevant by any of the participating authors were included in the study. DATA SYNTHESIS: No quantitative synthesis of data was performed. Instead we formulated a consensus view of the information that should be offered to all patients with CD. RESULTS: There are few randomized clinical trials examining the effect of patient support in CD. Patients and their families receive information from many sources. It is important that health care personnel guide the patient through the plethora of facts and comments on the Internet. An understanding of CD is likely to improve dietary adherence. Patients should be educated about current knowledge about risk factors for CD, as well as the increased risk of complications. Patients should also be advised to avoid other health hazards, such as smoking. Many patients are eager to learn about future non-dietary treatments of CD. This review also comments on novel therapies but it is important to stress that no such treatment is available at present. CONCLUSION: Based on mostly observational data, we suggest that patient support and information should be an integral part of the management of CD, and is likely to affect the outcome of CD.

The gluten-free diet and its current application in coeliac disease and dermatitis herpetiformis.

BACKGROUND: A gluten-free diet (GFD) is currently the only available therapy for coeliac disease (CD). OBJECTIVES: We aim to review the literature on the GFD, the gluten content in naturally gluten-free (GF) and commercially available GF food, standards and legislation concerning the gluten content of foods, and the vitamins and mineral content of a GFD. METHODS: We carried out a PubMed search for the following terms: Gluten, GFD and food, education, vitamins, minerals, calcium, Codex wheat starch and oats. Relevant papers were reviewed and for each topic a consensus among the authors was obtained. CONCLUSION: Patients with CD should avoid gluten and maintain a balanced diet to ensure an adequate intake of nutrients, vitamins, fibre and calcium. A GFD improves symptoms in most patients with CD. The practicalities of this however, are difficult, as (i) many processed foods are contaminated with gluten, (ii) staple GF foods are not widely available, and (iii) the GF substitutes are often expensive. Furthermore, (iv) the restrictions of the diet may adversely affect social interactions and quality of life. The inclusion of oats and wheat starch in the diet remains controversial.

Exome sequencing of 75 individuals from multiply affected coeliac families and large scale resequencing follow up.

Coeliac disease (CeD) is a highly heritable common autoimmune disease involving chronic small intestinal inflammation in response to dietary wheat. The human leukocyte antigen (HLA) region, and 40 newer regions identified by genome wide association studies (GWAS) and dense fine mapping, account for ∼40% of the disease heritability. We hypothesized that in pedigrees with multiple individuals with CeD rare [minor allele frequency (MAF) <0.5%] mutations of larger effect size (odds ratios of ∼2-5) might exist. We sequenced the exomes of 75 coeliac individuals of European ancestry from 55 multiply affected families. We selected interesting variants and genes for further follow up using a combination of: an assessment of shared variants between related subjects, a model-free linkage test, and gene burden tests for multiple, potentially causal, variants. We next performed highly multiplexed amplicon resequencing of all RefSeq exons from 24 candidate genes selected on the basis of the exome sequencing data in 2,248 unrelated coeliac cases and 2,230 controls. 1,335 variants with a 99.9% genotyping call rate were observed in 4,478 samples, of which 939 were present in coding regions of 24 genes (Ti/Tv 2.99). 91.7% of coding variants were rare (MAF <0.5%) and 60% were novel. Gene burden tests performed on rare functional variants identified no significant associations (p<1×10(-3)) in the resequenced candidate genes. Our strategy of sequencing multiply affected families with deep follow up of candidate genes has not identified any new CeD risk mutations.

Innate immune factors in the development and maintenance of pouchitis.

BACKGROUND: Tight junction proteins (TJPs) and dendritic cells (DC) are critical in the pathogenesis of inflammatory bowel diseases. The ileal pouch formed by restorative proctocolectomy provides a unique human model for studying the pathogenesis of inflammatory bowel diseases. Data implicate the microbiota in the pathogenesis of pouchitis, while the role of innate immune factors remains unclear. We performed longitudinal and cross-sectional studies of patients after restorative proctocolectomy and assessed TJP and DC characteristics in the ileal pouch. METHODS: Mucosal biopsies were taken from the ileal pouch of patients with ulcerative colitis (UC) and familial adenomatous polyposis (n = 8). Of patients with UC, one group (n = 5) was followed longitudinally over the first year after ileostomy closure, another group had pouchitis (n = 15), and another group no inflammation (n = 18). Dendritic cell phenotype and epithelial cell TJP expression were assessed using flow cytometric analysis. RESULTS: Increased epithelial expression of the "pore-forming" TJP claudin 2, and DC expression of gut-homing markers CCR 9 and integrin ß7, occurred early after ileostomy closure. In patients with UC with pouchitis, epithelial expression of ZO-1 and claudin 1 were reduced, DC were activated with increased CD40, and Toll-like receptor 4 expression increased. In pouchitis, DC expressing CCR 9 were decreased, whereas DC expressing ß7 increased. CONCLUSIONS: Abnormalities were found in TJP expression in the pouch of patients with UC, in particular, increased expression of the pore-forming claudin 2 as an early event in the development of pouch inflammation and an aberrant DC phenotype was characterized in the ileal pouch of patients with UC.

Diagnosis and management of adult coeliac disease: guidelines from the British Society of Gastroenterology.

A multidisciplinary panel of 18 physicians and 3 non-physicians from eight countries (Sweden, UK, Argentina, Australia, Italy, Finland, Norway and the USA) reviewed the literature on diagnosis and management of adult coeliac disease (CD). This paper presents the recommendations of the British Society of Gastroenterology. Areas of controversies were explored through phone meetings and web surveys. Nine working groups examined the following areas of CD diagnosis and management: classification of CD; genetics and immunology; diagnostics; serology and endoscopy; follow-up; gluten-free diet; refractory CD and malignancies; quality of life; novel treatments; patient support; and screening for CD.

Gastrointestinal effects of eating quinoa (Chenopodium quinoa Willd.) in celiac patients.

OBJECTIVES: Celiac disease is an enteropathy triggered by dietary gluten found in wheat, rye, and barley. Treatment involves a strict gluten-free diet (GFD). Quinoa is a highly nutritive plant from the Andes that has been recommended as part of a GFD. However, in-vitro data suggested that quinoa prolamins can stimulate innate and adaptive immune responses in celiac patients. Therefore, we aimed to evaluate the in-vivo effects of eating quinoa in adult celiac patients. METHODS: Nineteen treated celiac patients consumed 50 g of quinoa every day for 6 weeks as part of their usual GFD. We evaluated diet, serology, and gastrointestinal parameters. Furthermore, we carried out detail histological assessment of 10 patients before and after eating quinoa. RESULTS: Gastrointestinal parameters were normal. The ratio of villus height to crypt depth improved from slightly below normal values (2.8:1) to normal levels (3:1), surface-enterocyte cell height improved from 28.76 to 29.77 µm and the number of intra-epithelial lymphocytes per 100 enterocytes decreased from 30.3 to 29.7. Median values for all the blood tests remained within normal ranges, although total cholesterol (n=19) decreased from 4.6 to 4.3 mmol/l, low-density lipoprotein decreased from 2.46 to 2.45 mmol/l, high-density lipoprotein decreased from 1.8 to 1.68 mmol/l and triglycerides decreased from 0.80 to 0.79 mmol/l. CONCLUSIONS: Addition of quinoa to the GFD of celiac patients was well tolerated and did not exacerbate the condition. There was a positive trend toward improved histological and serological parameters, particularly a mild hypocholesterolemic effect. Overall, this is the first clinical data suggesting that daily 50 g of quinoa for 6 weeks can be safely tolerated by celiac patients. However, further studies are needed to determine the long-term effects of quinoa consumption.

PacBio sequencing of gene families - a case study with wheat gluten genes.

Amino acids in wheat (Triticum aestivum) seeds mainly accumulate in storage proteins called gliadins and glutenins. Gliadins contain α/ß-, γ- and ω-types whereas glutenins contain HMW- and LMW-types. Known gliadin and glutenin sequences were largely determined through cloning and sequencing by capillary electrophoresis. This time-consuming process prevents us to intensively study the variation of each orthologous gene copy among cultivars. The throughput and sequencing length of Pacific Bioscience RS (PacBio) single molecule sequencing platform make it feasible to construct contiguous and non-chimeric RNA sequences. We assembled 424 wheat storage protein transcripts from ten wheat cultivars by using just one single-molecule-real-time cell. The protein genes from wheat cultivar Chinese Spring are comparable to known sequences from NCBI. We demonstrated real-time sequencing of gene families with high-throughput and low-cost. This method can be applied to studies of gene amplification and copy number variation among species and cultivars.