Evaluation of the safety of ancient strains of wheat in coeliac disease reveals heterogeneous small intestinal T cell responses suggestive of coeliac toxicity

Gluten-free diet for pediatric patients with coeliac disease: A position paper from the ESPGHAN gastroenterology committee, special interest group in coeliac disease

BACKGROUND AND OBJECTIVE

Coeliac disease is a chronic, immune-mediated disorder for which the only treatment consists of lifelong strict adherence to gluten-free diet (GFD). However, there is a lack of evidence-based guidelines on the GFD dietary management of coeliac disease. This position paper, led by the Special Interest Group in coeliac disease of the European Society of Pediatric, Gastroenterology Hepatology, and Nutrition, supported by the Nutrition Committee and the Allied Health Professionals Committee, aims to present evidence-based recommendations on the GFD as well as how to support dietary adherence.

METHODS

A wide literature search was performed using the MeSH Terms: "diet, gluten free," "gluten-free diet," "diets, gluten-free," "gluten free diet," and "coeliac disease" in Pubmed until November 8th, 2022.

RESULTS

The manuscript provides an overview of the definition of the GFD, regulations as basis to define the term "gluten-free," which foods are naturally gluten-free and gluten-containing. Moreover, it provides recommendations and educational tips and infographics on suitable food substitutes, the importance of reading food labels, risk of gluten cross-contact at home and in public settings, nutritional considerations as well as factors associated to dietary adherence based on available evidence, or otherwise clinical expertise.

CONCLUSIONS

This position paper provides guidance and recommendations to support children with coeliac disease to safely adhere to a GFD.

Two randomized crossover multicenter studies investigating gastrointestinal symptoms after bread consumption in individuals with noncoeliac wheat sensitivity: do wheat species and fermentation type matter?

BACKGROUND

Many individuals reduce their bread intake because they believe wheat causes their gastrointestinal (GI) symptoms. Different wheat species and processing methods may affect these responses.

OBJECTIVES

We investigated the effects of 6 different bread types (prepared from 3 wheat species and 2 fermentation conditions) on GI symptoms in individuals with self-reported noncoeliac wheat sensitivity (NCWS).

METHODS

Two parallel, randomized, double-blind, crossover, multicenter studies were conducted. NCWS individuals, in whom coeliac disease and wheat allergy were ruled out, received 5 slices of yeast fermented (YF) (study A, n = 20) or sourdough fermented (SF) (study B, n = 20) bread made of bread wheat, spelt, or emmer in a randomized order on 3 separate test days. Each test day was preceded by a run-in period of 3 d of a symptom-free diet and separated by a wash-out period of ≥7 d. GI symptoms were evaluated by change in symptom score (test day minus average of the 3-d run-in period) on a 0-100 mm visual analogue scale (ΔVAS), comparing medians using the Friedman test. Responders were defined as an increase in ΔVAS of ≥15 mm for overall GI symptoms, abdominal discomfort, abdominal pain, bloating, and/or flatulence.

RESULTS

GI symptoms did not differ significantly between breads of different grains [YF bread wheat median ΔVAS 10.4 mm (IQR 0.0-17.8 mm), spelt 4.9 mm (-7.6 to 9.4 mm), emmer 11.0 mm (0.0-21.3 mm), P = 0.267; SF bread wheat 10.5 mm (-3.1 to 31.5 mm), spelt 11.3 mm (0.0-15.3 mm), emmer 4.0 mm (-2.9 to 9.3 mm), P = 0.144]. The number of responders was also comparable for both YF (6 to wheat, 5 to spelt, and 7 to emmer, P = 0.761) and SF breads (9 to wheat, 7 to spelt, and 8 to emmer, P = 0.761).

CONCLUSIONS

The majority of NCWS individuals experienced some GI symptoms for ≥1 of the breads, but on a group level, no differences were found between different grains for either YF or SF breads.

CLINICAL TRIAL REGISTRY

clinicaltrials.gov, NCT04084470 (https://classic.

CLINICALTRIALS

gov/ct2/show/NCT04084470).

New Developments in Celiac Disease Treatment

Celiac disease (CD) is a common autoimmune disease affecting around 1% of the population. It consists of an immune-mediated enteropathy, triggered by gluten exposure in susceptible patients. All patients with CD, irrespective of the presence of symptoms, must endure a lifelong gluten-free diet (GFD). This is not an easy task due to a lack of awareness of the gluten content in foods and the extensive incorporation of gluten in processed foods. Furthermore, a GFD imposes a sense of limitation and might be associated with decreased quality of life in CD patients. This results in gluten contamination in the diet of four out of five celiac patients adhering to a GFD. Furthermore, one in three adult patients will report persistent symptoms and two in three will not achieve full histological recovery when on a GFD. In recent years, there has been extensive research conducted in the quest to find the holy grail of pharmacological treatment for CD. This review will present a concise description of the current rationale and main clinical trials related to CD drug therapy.

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.

Do ancient wheats contain less gluten than modern bread wheat, in favour of better health?

Popular media messaging has led to increased public perception that gluten‐containing foods are bad for health. In parallel, ‘ancient grains’ have been promoted with claims that they contain less gluten. There appears to be no clear definition of ‘ancient grains’ but the term usually includes einkorn, emmer, spelt and Khorasan wheat. Gluten is present in all wheat grains and all can induce coeliac disease (CD) in genetically susceptible individuals. Analyses of ‘ancient’ and ‘modern’ wheats show that the protein content of modern bread wheat (Triticum aestivum) has decreased over time while the starch content increased. In addition, it was shown that, compared to bread wheat, ancient wheats contain more protein and gluten and greater contents of many CD‐active epitopes. Consequently, no single wheat type can be recommended as better for reducing the risks of or mitigating the severity of CD. An estimated 10% of the population of Western countries suffers from gastrointestinal symptoms that lack a clear organic cause and is often referred to as irritable bowel syndrome (IBS). Many of these patients consider themselves gluten sensitive, but in most cases this is not confirmed when tested in a medical setting. Instead, it may be caused by gas formation due to fermentation of fructans present in wheat or, in some patients, effects of non‐gluten proteins. A significant overlap of symptoms with those of CD, IBS and inflammatory bowel disease makes a medical diagnosis a priority. This critical narrative review examines the suggestion that ‘ancient’ wheat types are preferred for health and better tolerance.

Spanish Spelt Wheat: From an Endangered Genetic Resource to a Trendy Crop

Spelt wheat (Triticum aestivum L. ssp. spelta Thell.) is an ancient wheat that was widely cultivated in the past. This species derived from a cross between emmer wheat (T. turgidum spp. dicoccum Schrank em. Thell.) and Aegilops tauschii Coss. Its main origin was in the Fertile Crescent (Near East), with a secondary center of origin in Europe due to a second hybridization event between emmer and hexaploid wheat. This species has been neglected in most of Europe; however, the desire for more natural foods has driven a revival in interest. Iberian spelt is classified as a geographical group differing to the rest of European spelt. In this review, the particularities, genetic diversity and current situation of Spanish spelt, mainly for quality traits, are discussed.

Ancient Wheat Species: Biochemical Profile and Impact on Sourdough Bread Characteristics—A Review

In recent years, the attention of farmers, bakers and consumers towards ancient wheat species has been increasing. Low demands of pedo-climatic growth factors, the suitability for organic cultivation along with their high nutritional quality and their content in pro-health compounds make them extremely attractive for bakers and modern consumers, equally. On the other hand, in recent years, sourdough has gained attention due to its ability to produce new functionally active molecules with higher bioaccessibility and thus to produce bread with enhanced nutritional quality. This paper highlights the relevant nutritional profile of einkorn, spelt, emmer and Khorasan which could lead to bread with improved textural, sensorial, microbial and nutritional characteristics through sourdough fermentation. The ancient wheat species could be used as promising substitutes for common wheat flour for the design of innovative types of bread, even for special needs.

Ancient and Modern Cereals as Ingredients of the Gluten-Free Diet: Are They Safe Enough for Celiac Consumers?

Celiac disease is an autoimmune disorder that occurs in genetically predisposed individuals after consuming prolamins from some cereals. Although the products available for celiac subjects have increased significantly in quality and quantity over the last few decades, research still focuses on identifying new ingredients to improve the nutritional, sensorial and functional qualities of gluten-free products. In terms of toxicity for people with celiac disease, there is a wide variability between ancient and modern grains. The most contradictory results are related to the role of oats in the gluten-free diet. In order to clarify the role of minor cereals (such as oat) and ancient grains in the diets of celiac patients, this review discusses recent in vitro and in vivo studies performed on those cereals for which the toxicity for celiac subjects is still controversial. According to in vivo studies, selected oat varieties could be tolerated by celiac patients. On the other hands, although some wheat-ancient grains (Triticum monococcum, Triticum aestivum ssp. spelta and Kamut^®) showed a reduced in vitro toxicity, to date, these grains are still considered toxic for celiac patients. Contradictory results underline the importance of studying the safety of "unusual" cereals in more detail.

Could Global Intensification of Nitrogen Fertilisation Increase Immunogenic Proteins and Favour the Spread of Coeliac Pathology?

Fertilisation of cereal crops with nitrogen (N) has increased in the last five decades. In particular, the fertilisation of wheat crops increased by nearly one order of magnitude from 1961 to 2010, from 9.84 to 93.8 kg N ha-1 y-1. We hypothesized that this intensification of N fertilisation would increase the content of allergenic proteins in wheat which could likely be associated with the increased pathology of coeliac disease in human populations. An increase in the per capita intake of gliadin proteins, the group of gluten proteins principally responsible for the development of coeliac disease, would be the responsible factor. We conducted a global meta-analysis of available reports that supported our hypothesis: wheat plants growing in soils receiving higher doses of N fertilizer have higher total gluten, total gliadin, α/β-gliadin, γ-gliadin and ω-gliadin contents and higher gliadin transcription in their grain. We thereafter calculated the per capita annual average intake of gliadins from wheat and derived foods and found that it increased from 1961 to 2010 from approximately 2.4 to 3.8 kg y-1 per capita (+1.4 ± 0.18 kg y-1 per capita, mean ± SE), i.e., increased by 58 ± 7.5%. Finally, we found that this increase was positively correlated with the increase in the rates of coeliac disease in all the available studies with temporal series of coeliac disease. The impacts and damage of over-fertilisation have been observed at an environmental scale (e.g., eutrophication and acid rain), but a potential direct effect of over-fertilisation is thus also possible on human health (coeliac disease).

Comparative Analysis of in vitro Digestibility and Immunogenicity of Gliadin Proteins From Durum and Einkorn Wheat

Recent studies suggested that gliadin proteins from the ancient diploid einkorn wheat Triticum monococcum retained a reduced number of immunogenic peptides for celiac disease patients because of a high in vitro digestibility with respect to hexaploid common wheat. In this study, we compared the immunological properties of gliadins from two Triticum monococcum cultivars (Hammurabi and Norberto-ID331) with those of a Triticum durum cultivar (Adamello). Gliadins were digested by mimicking the in vitro gastrointestinal digestion process that includes the brush border membrane peptidases. Competitive ELISA, based on R5 monoclonal antibody, showed that gastrointestinal digestion reduced the immunogenicity of Triticum monococcum gliadins; conversely, the immunogenic potential of Triticum durum gliadins remained almost unchanged by the in vitro digestion. The immune stimulatory activity was also evaluated by detecting the IFN-γ production in gliadin-reactive T-cell lines obtained from the small intestinal mucosa of HLA-DQ2+ celiac disease patients. Interestingly, gastrointestinal digestion markedly reduced the capability of Triticum monococcum gliadins (p <0.05) of both cultivars to activate T cells, while it slightly affected the activity of Triticum durum. In conclusion, our results showed that Triticum durum was almost unaffected by the in vitro gastrointestinal digestion, while Triticum monococcum had a marked sensibility to digestion, thus determining a lower toxicity for celiac disease patients.

In Celiac Disease Patients the In Vivo Challenge with the Diploid Triticum monococcum Elicits a Reduced Immune Response Compared to Hexaploid Wheat

SCOPE

Gluten from the diploid wheat Triticum monococcum (TM) has low content of immunostimulatory sequences and a high gastro-intestinal digestibility. Gluten-reactive T cells elicited by diploid and hexaploid (Triticum aestivum-TA) wheat in celiac disease (CD) patients upon a brief oral challenge are analyzed.

METHODS AND RESULTS

Seventeen patients with CD (median age 13 years) consumed for 3 days sandwiches made with TM (cultivar Norberto-ID331, N=11), or TA (cultivar Sagittario, N=11) flours, corresponding to 12 gr of gluten/die. Immunostimulatory properties are assessed in blood by measuring the IFN-γ-secreting T cells by EliSpot and the expression of inflammatory cytokines/receptors (IL-12A, IL-15, IL-18RAP, IFN-γ) by qPCR. TA mobilizes a remarkable number of gliadin-specific, IFN-γ-secreting T cells (p<0.05), while no significant cell mobilization is induced by TM (p=ns). Similar results are obtained in response to five immunogenic peptides from α-, ω-, and γ-gliadins, although with a large individual variability. An increased mRNA expression for IL-12A and IFN-γ is detected in the group eating TA compared to those consuming TM (p<0.05).

CONCLUSIONS

Although T. monococcum is a cereal not suitable for the diet of celiacs, this diploid wheat elicits a reduced in vivo T-cell response compared to T. aestivum in celiac patients.

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.

Adverse Reactions to Wheat or Wheat Components

Wheat is an important staple food globally, providing a significant contribution to daily energy, fiber, and micronutrient intake. Observational evidence for health impacts of consuming more whole grains, among which wheat is a major contributor, points to significant risk reduction for diabetes, cardiovascular disease, and colon cancer. However, specific wheat components may also elicit adverse physical reactions in susceptible individuals such as celiac disease (CD) and wheat allergy (WA). Recently, broad coverage in the popular and social media has suggested that wheat consumption leads to a wide range of adverse health effects. This has motivated many consumers to avoid or reduce their consumption of foods that contain wheat/gluten, despite the absence of diagnosed CD or WA, raising questions about underlying mechanisms and possible nocebo effects. However, recent studies did show that some individuals may suffer from adverse reactions in absence of CD and WA. This condition is called non-celiac gluten sensitivity (NCGS) or non-celiac wheat sensitivity (NCWS). In addition to gluten, wheat and derived products contain many other components which may trigger symptoms, including inhibitors of α-amylase and trypsin (ATIs), lectins, and rapidly fermentable carbohydrates (FODMAPs). Furthermore, the way in which foods are being processed, such as the use of yeast or sourdough fermentation, fermentation time and baking conditions, may also affect the presence and bioactivity of these components. The present review systematically describes the characteristics of wheat-related intolerances, including their etiology, prevalence, the components responsible, diagnosis, and strategies to reduce adverse reactions.

Scouting for Naturally Low-Toxicity Wheat Genotypes by a Multidisciplinary Approach

Over the last years, great efforts have been devoted to develop effective gluten detoxification strategies with a consequent detrimental alteration of the technological properties as well. Obtaining low-gluten products without affecting the rheological properties of wheat could still be considered a new challenge to face. In this investigation, we presented a comprehensive characterization of durum wheat genotypes aimed at identifying low gluten ones, which combine the potential lower toxicity/immunogenicity with conserved yield and rheological properties to encompass the perspective usability for bread or pasta making. A preliminary profiling of gluten proteins was accomplished by immunoassay-based quantification and liquid chromatography coupled to UV detection, focusing on the gliadin fraction as main responsible for immunoreactivity in celiac disease patients. In addition, data on grain protein content, grain yield per spike, dry gluten and gluten index were collected in order to provide complementary information about productivity-related traits and quali-quantitative characteristics related to wheat nutritional value and its technological properties. The whole pool of data was statistically evaluated driving to the selection of a preferred list of candidate low-toxicity genotypes that were subjected to in-vitro simulated gastroduodenal digestion and untargeted HR-MS/MS peptide identification. Finally, an in-silico risk assessment of potential toxicity for celiac disease patients was performed according to the most recent guidance provided by EFSA.

Coeliac disease

Coeliac disease is an immune-mediated enteropathy against dietary gluten present in wheat, rye and barley and is one of the most common lifelong food-related disorders worldwide. Coeliac disease is also considered to be a systemic disorder characterized by a variable combination of gluten-related signs and symptoms and disease-specific antibodies in addition to enteropathy. The ingestion of gluten leads to the generation of harmful gluten peptides, which, in predisposed individuals, can induce adaptive and innate immune responses. The clinical presentation is extremely variable; patients may have severe gastrointestinal symptoms and malabsorption, extraintestinal symptoms or have no symptoms at all. Owing to the multifaceted clinical presentation, diagnosis remains a challenge and coeliac disease is heavily underdiagnosed. The diagnosis of coeliac disease is achieved by combining coeliac disease serology and small intestinal mucosal histology during a gluten-containing diet. Currently, the only effective treatment for coeliac disease is a lifelong strict gluten-free diet; however, the diet is restrictive and gluten is difficult to avoid. Optimizing diagnosis and care in coeliac disease requires continuous research and education of both patients and health-care professionals.

Do ancient types of wheat have health benefits compared with modern bread wheat?

A number of studies have suggested that ancient wheats have health benefits compared with modern bread wheat. However, the mechanisms are unclear and limited numbers of genotypes have been studied, with a particular focus on Kamut^® (Khorasan wheat). This is important because published analyses have shown wide variation in composition between genotypes, with further effects of growth conditions. The present article therefore critically reviews published comparisons of the health benefits of ancient and modern wheats, in relation to the selection and growth of the lines, including dietary interventions and comparisons of adverse effects (allergy, intolerance, sensitivity). It is concluded that further studies are urgently required, particularly from a wider range of research groups, but also on a wider range of genotypes of ancient and modern wheat species. Furthermore, although most published studies have made efforts to ensure the comparability of material in terms of growth conditions and processing, it is essential that these are standardised in future studies and this should perhaps be a condition of publication.

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Critically appraises the health benefits of ancient wheats in relationship to grain composition.

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Includes human intervention trials and in vitro studies.

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Included metabolic and adverse effects.

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Makes recommendations for future work.

Ancient wheat species and human health: Biochemical and clinical implications

Wheat is the major staple food in many diets. Based on the increase in worldwide mortality attributable to diet-related chronic diseases, there is an increasing interest in identifying wheat species with greater health potential, more specifically for improved anti-oxidant and anti-inflammatory properties. In particular, ancient varieties (defined as those species that have remained unchanged over the last hundred years) are gaining interest since several studies suggested that they present a healthier nutritional profile than modern wheats. This manuscript reviews the nutritional value and health benefits of ancient wheats varieties, providing a summary of all in vitro, ex vivo, animal and human studies that have thus far been published. Differences in chemical composition, and biochemical and clinical implications of emmer, einkorn, spelt, khorasan and various regional Italian varieties are discussed. Although many studies based on in vitro analyses of grain components provide support to the premise of a healthier nutritional and functional potential of ancient wheat, other in vitro studies performed are not in support of an improved potential of ancient varieties. In the light of existing evidence derived from in vivo experiments, the ancient wheat varieties have shown convincing beneficial effects on various parameters linked to cardio-metabolic diseases such as lipid and glycaemic profiles, as well as the inflammatory and oxidative status. However, given the limited number of human trials, it is not possible to definitively conclude that ancient wheat varieties are superior to all modern counterparts in reducing chronic disease risk.

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.

Peptides from gluten digestion: A comparison between old and modern wheat varieties

Coeliac disease is an autoimmune enteropathy that develops in genetically predisposed subjects after the ingestion of gluten or related proteins. Coeliac disease has an increasing incidence in the last years in western countries and it has been suggested that wheat breeding might have contributed to select more toxic forms of gluten. In this work, we analysed gluten peptides generated by in vitro digestion of different old and modern Triticum varieties, using LC-MS. We concluded that old varieties analysed produced a higher quantity of peptides containing immunogenic and toxic sequences than modern ones. Thus old wheat lines are not to be considered "safer" for subjects that are genetically predisposed to celiac disease.

Novel avian single-chain fragment variable (scFv) targets dietary gluten and related natural grain prolamins, toxic entities of celiac disease

BACKGROUND

Celiac disease (CD) is a chronic, small intestinal inflammatory disease mediated by dietary gluten and related prolamins. The only current therapeutic option is maintenance of a strict life-long gluten-free diet, which implies substantial burden for CD patients. Different treatment regimes might be feasible, including masking of toxic celiac peptides with blocking antibodies or fragments thereof. The objective of this study was therefore to select and produce a recombinant avian single-chain fragment variable (scFv) directed against peptic-tryptic digested gliadin (PT-Gliadin) and related celiac toxic entities.

RESULTS

Gluten-free raised chicken of same age were immunized with PT-Gliadin. Chicken splenic lymphocytes, selected with antigen-coated magnetic beads, served as RNA source for the generation of cDNA. Chicken VH and VL genes were amplified from the cDNA by PCR to generate full-length scFv constructs consisting of VH and VL fragments joined by a linker sequence. ScFv constructs were ligated in a prokaryotic expression vector, which provides a C-terminal hexahistidine tag. ScFvs from several bacterial clones were expressed in soluble form and crude cell lysates screened for binding to PT-Gliadin by ELISA. We identified an enriched scFv motif, which showed reactivity to PT-Gliadin. One selected scFv candidate was expressed and purified to homogeneity. Polyclonal anti-PT-Gliadin IgY, purified from egg yolk of immunized chicken, served as control. ScFv binds in a dose-dependent manner to PT-Gliadin, comparable to IgY. Furthermore, IgY competitively displaces scFv from PT-Gliadin and natural wheat flour digest, indicating a common epitope of scFv and IgY. ScFv was tested for reactivity to different gastric digested dietary grain flours. ScFv detects common and khorasan wheat comparably with binding affinities in the high nanomolar range, while rye is detected to a lesser extent. Notably, barley and cereals which are part of the gluten-free diet, like corn and rice, are not detected by scFv. Similarly, the pseudo-grain amaranth, used as gluten-free alternative, is not targeted by scFv. This data indicate that scFv specifically recognizes toxic cereal peptides relevant in CD.

CONCLUSION

ScFv can be of benefit for future CD treatment regimes.

Extensive in vitro gastrointestinal digestion markedly reduces the immune-toxicity of Triticum monococcum wheat: implication for celiac disease

SCOPE

The ancient diploid Triticum monococcum is of special interest as a candidate low-toxic wheat species for celiac disease patients. Here, we investigated how an in vitro gastro-intestinal digestion, affected the immune toxic properties of gliadin from diploid compared to hexaploid wheat.

METHODS AND RESULTS

Gliadins from Triticum monococcum, and Triticum aestivum cultivars were digested using either a partial proteolysis with pepsin-chymotrypsin, or an extensive degradation that used gastrointestinal enzymes including the brush border membrane enzymes. The immune stimulatory properties of the digested samples were investigated on T-cell lines and jejunal biopsies from celiac disease patients. The T-cell response profile to the Triticum monococcum gliadin was comparable to that obtained with Triticum aestivum gliadin after the partial pepsin-chymotrypsin digestion. In contrast, the extensive gastrointestinal hydrolysis drastically reduced the immune stimulatory properties of Triticum monococcum gliadin. MS-based analysis showed that several Triticum monococcum peptides, including known T-cell epitopes, were degraded during the gastrointestinal treatment, whereas many of Triticum aestivum gliadin survived the gastrointestinal digestion.

CONCLUSION

The pattern of Triticum monococcum gliadin proteins is sufficiently different from those of common hexaploid wheat to determine a lower toxicity in celiac disease patients following in vitro simulation of human digestion.

The role of animal models in unravelling therapeutic targets in coeliac disease

Coeliac disease is a complex small intestinal enteropathy that develops consequently to a breach of tolerance to gliadin, a storage protein abundantly found in cereals such as wheat, rye and barley. The understanding of the mechanisms underlying the development of coeliac disease in HLA-DQ2 and HLA-DQ8 genetically susceptible individuals has greatly improved during the last decades but so far did not allow to develop curative therapeutics, leaving a long-life gluten free diet as the only treatment option for the patients. In order to bring new therapeutic targets to light and to test the safety and efficacy of putative drugs, animal models recapitulating features of the disease are needed. Here, we will review the existing animal models and the clinical features of coeliac disease they reflect and discuss their relevance for modelling immune pathways that may lead to potential therapeutic approaches.

Cereal-based gluten-free food: how to reconcile nutritional and technological properties of wheat proteins with safety for celiac disease patients

The gluten-free diet is, to date, the only efficacious treatment for patients with Celiac Disease. In recent years, the impressive rise of Celiac Disease incidence, dramatically prompted changes in the dietary habit of an increasingly large population, with a rise in demand of gluten-free products. The formulation of gluten-free bakery products presents a formidable challenge to cereal technologists. As wheat gluten contributes to the formation of a strong protein network, that confers visco-elasticity to the dough and allows the wheat flour to be processed into a wide range of products, the preparation of cereal-based gluten-free products is a somehow difficult process. This review focuses on nutritional and technological quality of products made with gluten-free cereals available on the market. The possibility of using flour from naturally low toxic ancient wheat species or detoxified wheat for the diet of celiacs is also discussed.