Gluten in Celiac Disease-More or Less?

Product safety aspects of plant molecular farming

Plant molecular farming (PMF) has been promoted since the 1990s as a rapid, cost-effective and (most of all) safe alternative to the cultivation of bacteria or animal cells for the production of biopharmaceutical proteins. Numerous plant species have been investigated for the production of a broad range of protein-based drug candidates. The inherent safety of these products is frequently highlighted as an advantage of PMF because plant viruses do not replicate in humans and vice versa. However, a more nuanced analysis of this principle is required when considering other pathogens because toxic compounds pose a risk even in the absence of replication. Similarly, it is necessary to assess the risks associated with the host system (e.g., the presence of toxic secondary metabolites) and the production approach (e.g., transient expression based on bacterial infiltration substantially increases the endotoxin load). This review considers the most relevant host systems in terms of their toxicity profile, including the presence of secondary metabolites, and the risks arising from the persistence of these substances after downstream processing and product purification. Similarly, we discuss a range of plant pathogens and disease vectors that can influence product safety, for example, due to the release of toxins. The ability of downstream unit operations to remove contaminants and process-related toxic impurities such as endotoxins is also addressed. This overview of plant-based production, focusing on product safety aspects, provides recommendations that will allow stakeholders to choose the most appropriate strategies for process development.

Cross-Cultural Participation in Food-Related Activities and Quality of Life among Children with Celiac Disease

Children with celiac disease may face challenges in managing a gluten-free diet during their daily interactions and activities. The objective of this study was to compare how children with celiac disease manage their gluten-free diet and participate in food-related activities in Italy and Israel and to assess their quality of life. The previously validated Children's Activities Report (CD-Chart) and the Disease-specific Health-Related Quality of Life Questionnaire for Children with Celiac Disease (CDDUX) were administered in Italy to children aged 8-16 diagnosed with CD (n = 39). The results were compared to data that had been previously gathered from Israeli children with CD (n = 106). The CD-Chart demonstrated satisfactory internal reliability within each cultural group (Italy: α = 0.82; Israel: α = 0.76). Mann-Whitney U-tests indicated significant differences between the two groups. The Italian children exhibited a significantly higher preference for participating in the activities compared to the Israelis (U = 3283.50, p < 0.001). Nonetheless, the Italian children displayed a notable decrease in their level of involvement in the preparation required before engaging in different activities (U = 760.50, p < 0.001). Moreover, they exhibited significantly lower self-determination in this preparatory process compared to the Israeli children (U = 726.00, p < 0.001). Significant group differences were found between the CDDUX children's self-reports and parents' proxy reports in the Israeli group but not in the Italian group. The CD-Chart revealed both shared and distinct participation characteristics in daily food-related activities across different cultural contexts. By incorporating the CD-Chart and the CDDUX, healthcare professionals can emphasize crucial aspects of day-to-day health management and guide them in establishing suitable intervention objectives to enhance effective health self-management.

Systematic Review and Dose-Response Meta-Analysis on the Relationship between Different Gluten Doses and Risk of Coeliac Disease Relapse

Gluten proteins are known as immunological triggers for inflammation resulting in mucosal lesions in patients with coeliac disease (CD). Adherence to a strict gluten-free diet (GFD) is currently known as the only effective treatment for CD. In this study, we performed a systematic review and dose-response meta-analysis on data from previous studies to investigate the association between different gluten doses administered and the risk of CD relapse. Electronic databases were systematically searched to retrieve studies that investigated the response of CD patients to different amounts of gluten intake and evaluated the clinical, serologic, and/or histologic evidence to recognize disease relapse. Study-specific relative risks (RRs) were combined using a random effects model. A total of 440 identified published papers were screened, of which 7 records were selected following full-text reviewing and eligibility assessment for dose-response meta-analysis. According to our analysis, the risk of CD relapse is estimated to be 0.2% (RR: 1.002; 95% CI: 1.001 to 1.004) following the consumption of 6 mg gluten/day, which was increased to 7% (RR: 1.07; 95% CI: 1.03 to 1.10), 50% (RR: 1.50; 95% CI: 1.23 to 1.82), 80% (RR: 1.80; 95% CI: 1.36 to 2.38), and 100% (RR: 2.00; 95% CI: 1.43 to 2.78) by the daily intake of 150, 881, 1276, and 1505 mg gluten, respectively. Although good adherence to a GFD can adequately control CD-related symptoms, disease relapse might happen even with a very low dose of gluten, and the duration of exposure to gluten is also an important matter. The current literature has substantial limitations, such as relying on the data from just a few countries that were different in terms of the amount of gluten administered, the duration of the challenge, etc. Therefore, more randomized clinical trials using a standardized gluten challenge protocol are needed to confirm the findings of the present study.

A Highly Sensitive Method for the Detection of Hydrolyzed Gluten in Beer Samples Using LFIA

Most gluten analysis methods have been developed to detect intact gluten, but they have shown limitations in certain foods and beverages in which gluten proteins are hydrolyzed. Methods based on G12/A1 moAbs detect the sequences of gluten immunogenic peptides (GIP), which are the main contributors to the immune response of celiac disease (CD). Immunogenic sequences with tandem epitopes for G12/A1 have been found in beers with <20 mg/kg gluten, which could be consumed by CD patients according to the Codex Alimentarius. Therefore, an accurate method for the estimation of the immunogenicity of a beer is to use two moAbs that can recognize celiac T cell epitopes comprising most of the immunogenic response. Here, a specific and sensitive method based on G12/A1 LFIA was developed to detect GIP in beers labeled gluten-free or with low gluten content, with an LOD of 0.5 mg/kg. A total of 107 beers were analyzed, of those 6.5% showed levels higher than 20 mg/kg gluten and 29% showed levels above the LOD. In addition, G12/A1 LFIA detected gluten in 15 more beer samples than competitive ELISA with another antibody. Despite their labeling, these beers contained GIP which may cause symptoms and/or intestinal damage in CD patients.

A Comprehensive Review of the Neurological Manifestations of Celiac Disease and Its Treatment

Celiac disease (CD) is a common chronic inflammatory disorder occurring in genetically predisposed individuals secondary to gluten ingestion. CD usually presents with gastrointestinal symptoms such as pain, bloating, flatulence, and constipation or diarrhea. However, individuals can present in a nonclassical manner with only extraintestinal symptoms. The neurological manifestations of CD include ataxia, cognitive impairment, epilepsy, headache, and neuropathy. A lifelong gluten-free diet is the current recommended treatment for CD. This review discusses the relevant neurological manifestations associated with CD and the novel therapeutics. Further research is required to get a better understanding of the underlying pathophysiology of the neurological manifestations associated with CD. Clinicians should keep CD in the differential diagnosis in individuals presenting with neurological dysfunction of unknown cause.

Thin-Plate Superstructures of the Immunogenic 33-mer Gliadin Peptide

Gluten related-disorders have a prevalence of 1-5 % worldwide triggered by the ingestion of gluten proteins in wheat, rye, barley, and some oats. In wheat gluten, the most studied protein is gliadin, whose immunodominant 33-mer amino acid fragment remains after digestive proteolysis and accumulates in the gut mucosa. Here, we report the formation of 33-mer thin-plate superstructures using intrinsic tyrosine (Tyr) steady-state fluorescence anisotropy and cryo-TEM in combination with water tension measurements. Furthermore, we showed that fluorescence decay measurements of 33-mer intrinsic fluorophore Tyr provided information on the early stages of the formation of the thin-plate structures. Finally, conformational analysis of Tyr residues using minimalist models by molecular dynamic simulations (MD) demonstrated that changes in Tyr rotamer states depend on the oligomerization stage. Our findings further advance the understanding of the formation of the 33-mer gliadin peptide superstructures and their relation to health and disease.

Non-Celiac Gluten Sensitivity and Protective Role of Dietary Polyphenols

Pathogenetically characterized by the absence of celiac disease and wheat allergy, non-celiac gluten sensitivity (NCGS) is a clinical entity triggered by the consumption of gluten-containing foods that relieved by a gluten-free diet. Since it is very difficult to maintain a complete gluten-free diet, there is a high interest in discovering alternative strategies aimed at reducing gluten concentration or mitigating its toxic effects. Plant-based dietary models are usually rich in bioactive compounds, such as polyphenols, recognized to prevent, delay, or even reverse chronic diseases, including intestinal disorders. However, research on the role of polyphenols in mitigating the toxicity of gluten-containing foods is currently limited. We address the metabolic fate of dietary polyphenols, both as free and bound macromolecule-linked forms, with particular reference to the gastrointestinal compartment, where the concentration of polyphenols can reach high levels. We analyze the potential targets of polyphenols including the gluten peptide bioavailability, the dysfunction of the intestinal epithelial barrier, intestinal immune response, oxidative stress and inflammation, and dysbiosis. Overall, this review provides an updated overview of the effects of polyphenols as possible dietary strategies to counteract the toxic effects of gluten, potentially resulting in the improved quality of life of patients with gluten-related disorders.

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.

An interpretative phenomenological analysis of the development and maintenance of gluten-related distress and unhelpful eating and lifestyle patterns in coeliac disease

OBJECTIVE

Estimates indicate that individuals with coeliac disease are more likely to experience disordered eating and impaired well-being than healthy controls, but less is known about the mechanisms by which these factors are related. The aim of this study was to understand experiences of coeliac disease and influence on subsequent unhelpful eating and lifestyle patterns.

METHODS

An online focus group discussion, hosted through a synchronous chat log, with adults living with coeliac disease was conducted. Seven individuals discussed their condition, lifestyle, and dietary changes post-diagnosis. Discussions were analysed using an interpretative phenomenological approach, a technique that enables new practical or research insight into health conditions based upon participants' experiences of their condition.

RESULTS

Three themes were identified: (i) Nobody knew what was happening to my body; (ii) I am so afraid of being 'glutened' that it is central to my thoughts and anxieties; and (iii) I am frightened but I can keep myself safe by being a 'good' coeliac. These appeared to contribute to participant distress or unhelpful eating or lifestyle behaviours. Participants appeared to develop severe anxiety around gluten, and implausible beliefs around diet and lifestyle management that appear to initiate and maintain unhelpful eating behaviours and maladaptive lifestyles changes, that contribute to distress.

CONCLUSIONS

Extending current knowledge, we propose a novel cognitive perspective on the development and maintenance of disordered eating in coeliac disease. Implications for how health providers can better support individuals with coeliac disease, and the role of dietary management, anxiety, and gastrointestinal symptoms in the development of disordered eating are discussed.

New Insights into Non-Dietary Treatment in Celiac Disease: Emerging Therapeutic Options

To date, the only treatment for celiac disease (CD) consists of a strict lifelong gluten-free diet (GFD), which has numerous limitations in patients with CD. For this reason, dietary transgressions are frequent, implying intestinal damage and possible long-term complications. There is an unquestionable need for non-dietary alternatives to avoid damage by involuntary contamination or voluntary dietary transgressions. In recent years, different therapies and treatments for CD have been developed and studied based on the degradation of gluten in the intestinal lumen, regulation of the immune response, modulation of intestinal permeability, and induction of immunological tolerance. In this review, therapeutic lines for CD are evaluated with special emphasis on phase III and II clinical trials, some of which have promising results.

Unravelling the effects of procyanidin on gliadin digestion and immunogenicity

The effect of procyanidin dimer B3, a common food tannin, on the digestion of gliadin proteins was investigated by monitoring the changes in the immunogenic peptides produced during in vitro digestion and immunoreactivity. Interaction studies between procyanidin dimer B3, gluten proteins and/or digestive enzymes were performed by SDS-PAGE. The effect of procyanidin B3 on the enzymatic activity of trypsin, chymotrypsin and pancreatin was evaluated. The differences in the number and nature of immunogenic peptides released during digestion were identified by mass spectrometry. Briefly, the enzymatic activity of gastrointestinal enzymes was only slightly affected but a significant decrease in the immunological properties of the peptides produced during digestion was observed. Overall, although further studies are needed, the interaction between polyphenols and gluten proteins clearly influences gluten protein digestion and immunogenicity, thus suggesting that the consumption of dietary polyphenols can significantly affect the degree of celiac disease downstream immune reactions.

Peptidomics of an industrial gluten-free barley malt beer and its non-gluten-free counterpart: Characterisation and immunogenicity

Recent research suggests that gluten-free beers by prolyl-endopeptidase treatment may not be safe for coeliac disease (CD) patients. Therefore, the gluten peptidome of an industrial gluten-free prolyl-endopeptidase treated malt beer (<10 ppm gluten) was compared to its untreated counterpart (58 ppm gluten) as a reference. NanoLC-HRMS analysis revealed the presence of 155 and 158 gluten peptides in the treated and reference beer, respectively. Characterisation of the peptides in treated beer showed that prolyl-endopeptidase activity was not complete with many peptides containing (multiple) internal proline-residues. Yet, prolyl-endopeptidase treatment did eliminate complete CD-immunogenic motifs, however, 18 peptides still contained partial, and potentially unsafe, motifs. In the reference beer respectively 7 and 37 gluten peptides carried (multiple) complete and/or partial CD-immunogenic motifs. Worrying is that many of these partial immunogenic gluten peptides do not contain a recognition epitope for the R5-antibody and would be overlooked in the current ELISA analysis for gluten quantification.

Methods for the Modification and Evaluation of Cereal Proteins for the Substitution of Wheat Gluten in Dough Systems

The substitution of wheat gluten in the food industry is a relevant research area because the only known treatment for celiac disease is abstinence from this protein complex. The use of gluten-free cereals in dough systems has demonstrated that the viscoelastic properties of gluten cannot be achieved without the modification of the protein fraction. The quality of the final product is determined by the ability of the modification to form a matrix similar to that of gluten and to reach this, different methods have been proposed and tested. These procedures can be classified into four main types: chemical, enzymatic, physical, and genetic. This article provides a comprehensive review of the most recent research done in protein modification of cereal and pseudocereals for gluten substitution. The reported effects and methodologies for studying the changes made with each type of modification are described; also, some opportunity areas for future works regarding the study of the effect of protein modifications on gluten-free products are presented.

Substituting wheat flour with okara flour in biscuit production

Introduction. High fiber bakery products can be a healthy snack option for consumers. Our study focused on the effect of replacing wheat flour with okara flour on the physicochemical, nutritional, textural, and sensory attributes of biscuits. Study objects and methods. We used 2, 4, 6, and 8% w/w okara flour to prepare biscuits. Refined wheat flour (control), mixed flour (okara and wheat flour), dough, and biscuits were assessed for physicochemical, textural, and nutritional properties, as well as sensory characteristics. The volume of particles was higher in 8% okara flour (145 μm) compared to refined wheat flour (91 μm). Results and discussion. 2, 4, 6, and 8% w/w okara flour biscuits showed significantly (P ≤ 0.05) lower spread ratio and weight loss than biscuits from wheat flour. Hardness, stickiness, and cohesiveness of 2, 4, 6, and 8% okara flour dough were significantly (P ≤ 0.05) lower compared to the control, resulting in decreased cutting strength and increased hardness of okara flour biscuits. Moisture, protein, ash, fat, and crude fiber contents of 2, 4, 6, and 8% okara biscuits were significantly (P ≤ 0.05) higher compared to the control biscuits. The sensory evaluation suggested that 4% okara biscuits had higher consumer acceptability and were superior to the control and other okara biscuits. Conclusion. Mixed flour biscuits made from okara and wheat flours were superior in physicochemical, nutritional, textural, and sensory attributes, which allows considering them as an alternative healthy snack.

Nanoelectrode Arrays Fabricated by Thermal Nanoimprint Lithography for Biosensing Application

Electrochemical sensors are devices capable of detecting molecules and biomolecules in solutions and determining the concentration through direct electrical measurements. These systems can be miniaturized to a size less than 1 µm through the creation of small-size arrays of nanoelectrodes (NEA), offering advantages in terms of increased sensitivity and compactness. In this work, we present the fabrication of an electrochemical platform based on an array of nanoelectrodes (NEA) and its possible use for the detection of antigens of interest. NEAs were fabricated by forming arrays of nanoholes on a thin film of polycarbonate (PC) deposited on boron-doped diamond (BDD) macroelectrodes by thermal nanoimprint lithography (TNIL), which demonstrated to be a highly reliable and reproducible process. As proof of principle, gliadin protein fragments were physisorbed on the polycarbonate surface of NEAs and detected by immuno-indirect assay using a secondary antibody labelled with horseradish peroxidase (HRP). This method allows a successful detection of gliadin, in the range of concentration of 0.5-10 μg/mL, by cyclic voltammetry taking advantage from the properties of NEAs to strongly suppress the capacitive background signal. We demonstrate that the characteristics of the TNIL technology in the fabrication of high-resolution nanostructures together with their low-cost production, may allow to scale up the production of NEAs-based electrochemical sensing platform to monitor biochemical molecules for both food and biomedical applications.

The Epidemiology of Celiac Disease in the General Population and High-Risk Groups in Arab Countries: A Systematic Review

Background and Aims

Celiac disease (CD) is possibly the most common autoimmune disorder, which may lead to dietary problems in the Arab region. This paper is aimed at exploring the epidemiology of the celiac disease in Arab countries, including its prevalence, associated risk factors, and clinical patterns.

Methods

An extensive search of the literature was conducted from electronic databases such as PubMed, Embase, and Google Scholar. In total, 134 research papers were retrieved. We extracted studies published from January 1996 to December 2019. Our search was limited to studies published in English. Findings. The review included 35 studies with 22,340 participants from 12 countries and demonstrated a wide variation in the prevalence of CD. The highest prevalence among the general population (3.2%) was reported in Saudi Arabia, and the lowest (0.1%) was reported in Tunisia. Women demonstrated a higher prevalence of celiac disease relative to men. The peak age at diagnosis fell between 1 and 3 years and 9-10 years. Most studies focused on type 1 diabetes. Children with type 1 diabetes have a higher prevalence of CD (range from 5.5% to 20%), while the prevalence of CD in Down's syndrome patients was 1.1% and 10.7% in UAE and Saudi Arabia, respectively. Other autoimmune diseases associated with CD are thyroid disease and irritable bowel disease. The most widely recognized clinical presentation was an inability to flourish and poor weight gain, followed by short stature, abdominal pain, abdominal distension, bloating, and chronic diarrhea.

Conclusion

The prevalence of the celiac disease in Arab countries varies with sex and age. However, we found that celiac disease presented similar clinical characteristics independent of the geographic region. Longitudinal population-based studies are needed to better identify the true burden and determinants of celiac disease.

Pathogenesis of Celiac Disease and Other Gluten Related Disorders in Wheat and Strategies for Mitigating Them

Wheat is a major cereal crop providing energy and nutrients to the billions of people around the world. Gluten is a structural protein in wheat, that is necessary for its dough making properties, but it is responsible for imparting certain intolerances among some individuals, which are part of this review. Most important among these intolerances is celiac disease, that is gluten triggered T-cell mediated autoimmune enteropathy and results in villous atrophy, inflammation and damage to intestinal lining in genetically liable individuals containing human leukocyte antigen DQ2/DQ8 molecules on antigen presenting cells. Celiac disease occurs due to presence of celiac disease eliciting epitopes in gluten, particularly highly immunogenic alpha-gliadins. Another gluten related disorder is non-celiac gluten-sensitivity in which innate immune-response occurs in patients along with gastrointestinal and non-gastrointestinal symptoms, that disappear upon removal of gluten from the diet. In wheat allergy, either IgE or non-IgE mediated immune response occurs in individuals after inhalation or ingestion of wheat. Following a life-long gluten-free diet by celiac disease and non-celiac gluten-sensitivity patients is very challenging as none of wheat cultivar or related species stands safe for consumption. Hence, different molecular biology, genetic engineering, breeding, microbial, enzymatic, and chemical strategies have been worked upon to reduce the celiac disease epitopes and the gluten content in wheat. Currently, only 8.4% of total population is affected by wheat-related issues, while rest of population remains safe and should not remove wheat from the diet, based on false media coverage.

Celiac disease and gluten-free diet: past, present, and future

A gluten-free diet is a special type of diet intended for people with celiac disease. The objective of this article is to report the past, present production, supply of gluten-free products as well as their future position in our market. In the past, there were only limited gluten-free products available and the awareness of the diet was limited to paediatric community. There were only few raw gluten-free materials and almost all the production was created in households. Later with the introduction of targeted screening into the practice, celiac diagnosis has improved, with an increase in newly diagnosed patients who have remained life-long dependents on a gluten-free diet. This was associated with an increased production of gluten-free products, referred to as weight loss diet, with their positive effects on health. Subsequently, the gluten-free diet has also been voluntarily adopted by both people with other diseases and healthy individuals. In the future, the gluten-free diet consumption is expected to increase, due to its increased popularity in populations. In this regard, gluten-free diets have been misinterpreted as a "miracle drug" that is effective on a variety of problems. The medical community will be confronting the future problems of people who are dependent on a gluten-free diet as well as the complications arising from the consumers of a gluten-free diet for no medical reasons. Compliance to the principles of a gluten-free diet should be maintained and should not be recommended to healthy individuals or those without relevant reasons.

In vitro selection of anti-gliadin single-domain antibodies from a naïve library for cDNA-display mediated immuno-PCR

Gluten intolerance, or adverse intestinal reactions to gluten, is a fairly common problem among certain groups of people. Celiac disease is the most severe form of gluten intolerance, which can lead to permanent damage in the digestive system. Since lifelong avoidance of gluten is the only available treatment, development of reliable techniques to identify gluten contamination in food is important. Gliadin, a component of gluten, is known to play a major role in gluten toxicity. In this study, cDNA display method was used to select specific single-domain antibodies against toxic gliadin from an alpaca-derived naïve VHH library. The cDNA display method is a promising in vitro display technique, which uniquely converts an unstable mRNA-protein fusion molecule to a stable mRNA/cDNA-protein fusion molecule using a well-designed puromycin linker. Three candidate VHHs were selected and the affinities of the VHHs were observed by pulldown assay and indirect ELISA method. In addition, a novel cDNA display mediated immuno-PCR method (cD-IPCR) was successfully applied to detect gliadin in food. We believe this work demonstrates the potential application of the cDNA display method in selecting binders against toxic and heterogeneous targets such as gliadin with an immunization-free preparation manner.

Navigating the Gluten-Free Boom: The Dark Side of Gluten Free Diet

In gluten dependent conditions the gluten free diet is the cornerstone of therapy, decreasing disease activity, improving health and quality of life and treating or preventing the associated complications. Gluten withdrawal implies strict and lifelong elimination not only of wheat, barley, rye, and wheat-contaminated oats, but also of numerous non-nutritional products where components of wheat are often added. Due to multiple reasons the diet is difficult to follow and the long-term adherence is decreased with time. The present review summarizes the dark side of gluten restriction where nutritional deficiencies, toxicity, morbidity, mortality, and mental health problems are reported. The aim being to increase awareness, avoid, detect and treat the side effects and to promote a healthier nutrition, for the patient's benefits.