Dietary wheat amylase trypsin inhibitors exacerbate CNS inflammation in experimental multiple sclerosis.

OBJECTIVE: Wheat has become a main staple globally. We studied the effect of defined pro-inflammatory dietary proteins, wheat amylase trypsin inhibitors (ATI), activating intestinal myeloid cells via toll-like receptor 4, in experimental autoimmune encephalitis (EAE), a model of multiple sclerosis (MS). DESIGN: EAE was induced in C57BL/6J mice on standardised dietary regimes with defined content of gluten/ATI. Mice received a gluten and ATI-free diet with defined carbohydrate and protein (casein/zein) content, supplemented with: (a) 25% of gluten and 0.75% ATI; (b) 25% gluten and 0.19% ATI or (c) 1.5% purified ATI. The effect of dietary ATI on clinical EAE severity, on intestinal, mesenteric lymph node, splenic and central nervous system (CNS) subsets of myeloid cells and lymphocytes was analysed. Activation of peripheral blood mononuclear cells from patients with MS and healthy controls was compared. RESULTS: Dietary ATI dose-dependently caused significantly higher EAE clinical scores compared with mice on other dietary regimes, including on gluten alone. This was mediated by increased numbers and activation of pro-inflammatory intestinal, lymph node, splenic and CNS myeloid cells and of CNS-infiltrating encephalitogenic T-lymphocytes. Expectedly, ATI activated peripheral blood monocytes from both patients with MS and healthy controls. CONCLUSIONS: Dietary wheat ATI activate murine and human myeloid cells. The amount of ATI present in an average human wheat-based diet caused mild intestinal inflammation, which was propagated to extraintestinal sites, leading to exacerbation of CNS inflammation and worsening of clinical symptoms in EAE. These results support the importance of the gut-brain axis in inflammatory CNS disease.

Wheat amylase/trypsin inhibitors (ATIs): occurrence, function and health aspects.

Amylase/trypsin inhibitors (ATIs) are widely consumed in cereal-based foods and have been implicated in adverse reactions to wheat exposure, such as respiratory and food allergy, and intestinal responses associated with coeliac disease and non-coeliac wheat sensitivity. ATIs occur in multiple isoforms which differ in the amounts present in different types of wheat (including ancient and modern ones). Measuring ATIs and their isoforms is an analytical challenge as is their isolation for use in studies addressing their potential effects on the human body. ATI isoforms differ in their spectrum of bioactive effects in the human gastrointestinal (GI), which may include enzyme inhibition, inflammation and immune responses and of which much is not known. Similarly, although modifications during food processing (exposure to heat, moisture, salt, acid, fermentation) may affect their structure and activity as shown in vitro, it is important to relate these changes to effects that may present in the GI tract. Finally, much of our knowledge of their potential biological effects is based on studies in vitro and in animal models. Validation by human studies using processed foods as commonly consumed is warranted. We conclude that more detailed understanding of these factors may allow the effects of ATIs on human health to be better understood and when possible, to be ameliorated, for example by innovative food processing. We therefore review in short our current knowledge of these proteins, focusing on features which relate to their biological activity and identifying gaps in our knowledge and research priorities.

Lactobacilli Degrade Wheat Amylase Trypsin Inhibitors to Reduce Intestinal Dysfunction Induced by Immunogenic Wheat Proteins.

BACKGROUND & AIMS: Wheat-related disorders, a spectrum of conditions induced by the ingestion of gluten-containing cereals, have been increasing in prevalence. Patients with celiac disease have gluten-specific immune responses, but the contribution of non-gluten proteins to symptoms in patients with celiac disease or other wheat-related disorders is controversial. METHODS: C57BL/6 (control), Myd88-/-, Ticam1-/-, and Il15-/- mice were placed on diets that lacked wheat or gluten, with or without wheat amylase trypsin inhibitors (ATIs), for 1 week. Small intestine tissues were collected and intestinal intraepithelial lymphocytes (IELs) were measured; we also investigated gut permeability and intestinal transit. Control mice fed ATIs for 1 week were gavaged daily with Lactobacillus strains that had high or low ATI-degrading capacity. Nonobese diabetic/DQ8 mice were sensitized to gluten and fed an ATI diet, a gluten-containing diet or a diet with ATIs and gluten for 2 weeks. Mice were also treated with Lactobacillus strains that had high or low ATI-degrading capacity. Intestinal tissues were collected and IELs, gene expression, gut permeability and intestinal microbiota profiles were measured. RESULTS: In intestinal tissues from control mice, ATIs induced an innate immune response by activation of Toll-like receptor 4 signaling to MD2 and CD14, and caused barrier dysfunction in the absence of mucosal damage. Administration of ATIs to gluten-sensitized mice expressing HLA-DQ8 increased intestinal inflammation in response to gluten in the diet. We found ATIs to be degraded by Lactobacillus, which reduced the inflammatory effects of ATIs. CONCLUSIONS: ATIs mediate wheat-induced intestinal dysfunction in wild-type mice and exacerbate inflammation to gluten in susceptible mice. Microbiome-modulating strategies, such as administration of bacteria with ATI-degrading capacity, may be effective in patients with wheat-sensitive disorders.

Wheat amylase-trypsin inhibitors exacerbate intestinal and airway allergic immune responses in humanized mice.

BACKGROUND: Amylase-trypsin inhibitors (ATIs) in wheat and related cereals are potent activators of myeloid innate immune cells via engagement of TLR4. Furthermore, ATIs have been shown to serve as adjuvants in experimental intestinal inflammatory diseases. OBJECTIVE: The aim of this study was to analyze whether ATIs are also modifiers of allergic inflammation. METHODS: Therefore, CD4+ T cells from donors sensitized to grass or birch pollen were stimulated with autologous allergen-pulsed dendritic cells in the presence or absence of ATIs or the control storage protein zein from corn. To analyze allergen-induced gut and lung inflammation, immunodeficient mice were engrafted with PBMCs from these allergic donors plus the respective allergen, and fed with selected diets. Three weeks later, inflammation was induced by rectal or intranasal allergen challenge and monitored by mini endoscopy or airway hyperreactivity, respectively. RESULTS: Allergen-specific T-cell proliferation and cytokine production was significantly exacerbated by ATIs and not by zein. In vivo, allergen-specific human IgE level was strongly elevated in sera of mice receiving an ATI-containing diet compared with mice that were fed gluten-free and thus ATI-free diet. Importantly, allergen-induced IgE-dependent colitis and airway hyperreactivity were also enhanced in ATI-fed mice. Gut inflammation was further increased in mice receiving an additional ATI injection and even detectable in the absence of the aeroallergen, whereas zein had no such effect. Injection of anti-human TLR4 mAbs or the anti-human IgE mAb omalizumab completely abolished ATI-induced allergic inflammation. CONCLUSIONS: These results underline that wheat ATIs are important nutritional activators and adjuvants of allergy, which might be exploited for nutritional therapeutic strategies.

Dietary Wheat Amylase Trypsin Inhibitors Impact Alzheimer's Disease Pathology in 5xFAD Model Mice.

Wheat amylase trypsin inhibitors (ATIs) represent a common dietary protein component of gluten-containing cereals (wheat, rye, and barley). They act as toll-like receptor 4 ligands, and are largely resistant to intestinal proteases, eliciting a mild inflammatory response within the intestine after oral ingestion. Importantly, nutritional ATIs exacerbated inflammatory bowel disease and features of fatty liver disease and the metabolic syndrome in mice. For Alzheimer's disease (AD), both inflammation and altered insulin resistance are major contributing factors, impacting onset as well as progression of this devastating brain disorder in patients. In this study, we evaluated the impact of dietary ATIs on a well-known rodent model of AD (5xFAD). We assessed metabolic, behavioral, inflammatory, and microbial changes in mice consuming different dietary regimes with and without ATIs, consumed ad libitum for eight weeks. We demonstrate that ATIs, with or without a gluten matrix, had an impact on the metabolism and gut microbiota of 5xFAD mice, aggravating pathological hallmarks of AD. If these findings can be translated to patients, an ATI-depleted diet might offer an alternative therapeutic option for AD and warrants clinical intervention studies.

Histamine causes influx via T-type voltage-gated calcium channels in an enterochromaffin tumor cell line: potential therapeutic target in adverse food reactions.

The P-STS human ileal neuroendocrine tumor cells, as a model for gut enterochromaffin cells, are strongly and synergistically activated by histamine plus acetylcholine (ACh), presumably via histamine 4 receptors, and weakly activated by histamine alone. Sensing these signals, enterochromaffin cells could participate in intestinal intolerance or allergic reactions to food constituents associated with elevated histamine levels. In this study we aimed to analyze the underlying molecular mechanisms. Inhibition by mepyramine and mibefradil indicated that histamine alone caused a rise in intracellular calcium concentration ([Ca2+]i) via histamine 1 receptors involving T-type voltage-gated calcium channels (VGCCs). Sensitivity to histamine was enhanced by pretreatment with the inflammatory cytokine tumor necrosis factor-α (TNF-α). In accordance with the relief it offers some inflammatory bowel disease patients, otilonium bromide, a gut-impermeable inhibitor of T-type (and L-type) VGCCs and muscarinic ACh receptors, efficiently inhibited the [Ca2+]i responses induced by histamine plus ACh or by histamine alone in P-STS cells. It will take clinical studies to show whether otilonium bromide has promise for the treatment of adverse food reactions. The cells did not react to the nutrient constituents glutamate, capsaicin, cinnamaldehyde, or amylase-trypsin inhibitors and the transient receptor potential channel vanilloid 4 agonist GSK-1016790A. The bacterial product butyrate evoked a rise in [Ca2+]i only when added together with ACh. Lipopolysaccharide had no effect on [Ca2+]i despite the presence of Toll-like receptor 4 protein. Our results indicate that inflammatory conditions with elevated levels of TNF-α might enhance histamine-induced serotonin release from intestinal neuroendocrine cells. NEW & NOTEWORTHY We show that histamine synergistically enhances the intracellular calcium response to the physiological agonist acetylcholine in human ileal enterochromaffin tumor cells. This synergistic activation and cell activation by histamine alone largely depend on T-type voltage-gated calcium channels and are inhibited by the antispasmodic otilonium bromide. The cells showed no response to wheat amylase-trypsin inhibitors, suggesting that enterochromaffin cells are not directly involved in nongluten wheat sensitivity.

Dietary wheat amylase trypsin inhibitors exacerbate murine allergic airway inflammation.

BACKGROUND: Wheat amylase trypsin inhibitors (ATI) are dietary non-gluten proteins that activate the toll-like receptor 4 on myeloid cells, promoting intestinal inflammation. AIM OF THE STUDY: We investigated the effects of dietary ATI on experimental allergic airway inflammation. METHODS: Mice on a gluten and ATI-free diet (GAFD), sensitized with PBS or ovalbumin (OVA) and challenged with OVA, were compared to mice on a commercial standard chow, a gluten diet naturally containing ~ 0.75% of protein as ATI (G+AD), a gluten diet containing ~ 0.19% of protein as ATI (G-AD) and a GAFD with 1% of protein as ATI (AD). Airway hyperreactivity (AHR), inflammation in bronchoalveolar lavage (BAL) and pulmonary tissue sections were analyzed. Allergic sensitization was assessed ex vivo via proliferation of OVA-stimulated splenocytes. RESULTS: Mice on a GAFD sensitized with PBS did not develop AHR after local provocation with methacholine. Mice on a GAFD or on a G-AD and sensitized with OVA developed milder AHR compared to mice fed a G+AD or an AD. The increased AHR was paralleled by increased BAL eosinophils, IL-5 and IL-13 production, and an enhanced ex vivo splenocyte activation in the ATI-fed groups. CONCLUSIONS: Dietary ATI enhance allergic airway inflammation in OVA-challenged mice, while an ATI-free or ATI-reduced diet has a protective effect on AHR. Nutritional wheat ATI, activators of intestinal myeloid cells, may be clinically relevant adjuvants to allergic airway inflammation.

Nutritional Wheat Amylase-Trypsin Inhibitors Promote Intestinal Inflammation via Activation of Myeloid Cells.

BACKGROUND & AIMS: Wheat amylase-trypsin inhibitors (ATIs) are nutritional activators of innate immunity, via activation of the toll-like receptor 4 (TLR4) on myeloid cells. We aimed to characterize the biologic activity of ATIs in various foods and their effect on intestinal inflammation. METHODS: We selected 38 different gluten-containing and gluten-free products, either unprocessed (such as wheat, rye, barley, quinoa, amaranth, soya, lentils, and rice) or processed (such as pizza, pasta, bread, and biscuits). ATIs were extracted and their biological activities determined in TLR4-responsive mouse and human cell lines. Effects of oral ATIs on intestinal inflammation were determined in healthy C57BL/6 mice on a gluten-free or ATI-free diet and in mice given low-level polyinosinic:polycytidylic acid or dextran sodium sulfate to induce colitis. Parameters of innate and adaptive immune activation were determined in duodenum, ileum, colon, and mesenteric lymph nodes. RESULTS: Modern gluten-containing staples had levels of TLR4-activating ATIs that were as much as 100-fold higher than in most gluten-free foods. Processed or baked foods retained ATI bioactivity. Most older wheat variants (such as Emmer or Einkorn) had lower bioactivity than modern (hexaploid) wheat. ATI species CM3 and 0.19 were the most prevalent activators of TLR4 in modern wheat and were highly resistant to intestinal proteolysis. Their ingestion induced modest intestinal myeloid cell infiltration and activation, and release of inflammatory mediators-mostly in the colon, then in the ileum, and then in the duodenum. Dendritic cells became prominently activated in mesenteric lymph nodes. Concentrations of ATIs found in a normal daily gluten-containing diet increased low-level intestinal inflammation. CONCLUSIONS: Gluten-containing cereals have by far the highest concentrations of ATIs that activate TLR4. Orally ingested ATIs are largely resistant to proteases and heat, and increase intestinal inflammation by activating gut and mesenteric lymph node myeloid cells.

Nonceliac gluten sensitivity.

During the past decade there has been an impressive increase in popularity of the gluten-free diet (GFD)-now the most trendy alimentary habit in the United States and other countries. According to recent surveys, as many as 100 million Americans will consume gluten-free products within a year. Operating under the concept that the GFD benefits only individuals with celiac disease, health care professionals have struggled to separate the wheat from the chaff; there are claims that eliminating gluten from the diet increases health and helps with weight loss, or even that gluten can be harmful to every human being. However, apart from unfounded trends, a disorder related to ingestion of gluten or gluten-containing cereals, namely nonceliac gluten sensitivity (NCGS), has resurfaced in the literature, fueling a debate on the appropriateness of the GFD for people without celiac disease. Although there is clearly a fad component to the popularity of the GFD, there is also undisputable and increasing evidence for NCGS. However, we require a better understanding of the clinical presentation of NCGS, as well as its pathogenesis, epidemiology, management, and role in conditions such as irritable bowel syndrome, chronic fatigue, and autoimmunity. Before we can begin to identify and manage NCGS, there must be agreement on the nomenclature and definition of the disorder based on proper peer-reviewed scientific information. We review the most recent findings on NCGS and outline directions to dissipate some of the confusion related to this disorder.

Specific hepatic delivery of procollagen α1(I) small interfering RNA in lipid-like nanoparticles resolves liver fibrosis.

UNLABELLED: Fibrosis accompanies the wound-healing response to chronic liver injury and is characterized by excessive hepatic collagen accumulation dominated by collagen type I. Fibrosis often progresses to cirrhosis. Here we present in vivo evidence of an up to 90% suppression of procollagen α1(I) expression, a reduction of septa formation, and a 40%-60% decrease of collagen deposition in mice with progressive and advanced liver fibrosis that received cationic lipid nanoparticles loaded with small interfering RNA to the procollagen α1(I) gene. After intravenous injection, up to 90% of lipid nanoparticles loaded with small interfering RNA to the procollagen α1(I) gene were retained in the liver of fibrotic mice and accumulated in nonparenchymal more than parenchymal cells for prolonged periods, significantly ameliorating progression and accelerating regression of fibrosis. CONCLUSION: Our lipid nanoparticles loaded with small interfering RNA to the procollagen α1(I) gene specifically reduce total hepatic collagen content without detectable side effects, potentially qualifying as a therapy for fibrotic liver diseases.

Wheat amylase trypsin inhibitors as nutritional activators of innate immunity.

While the central role of an adaptive, T cell-mediated immune response to certain gluten peptides in celiac disease is well established, the innate immune response to wheat proteins remains less well defined. We identified wheat amylase trypsin inhibitors (ATIs), but not gluten, as major stimulators of innate immune cells (dendritic cells>macrophages>monocytes), while intestinal epithelial cells were nonresponsive. ATIs bind to and activate the CD14-MD2 toll-like receptor 4 (TLR4) complex. This activation occurs both in vitro and in vivo after oral ingestion of purified ATIs or gluten, which is usually enriched in ATIs. Wheat ATIs represent a family of up to 17 proteins with molecular weights of around 15 kDa and a variable primary but conserved secondary structure characterized by 5 intrachain disulfide bonds and alpha helices. They mostly form di- and tetramers that appear to equally activate TLR4. Relevant biological activity is confined to ATIs in gluten-containing cereals, while gluten-free cereals display no or minimal activities. ATIs represent up to 4% of total wheat protein and are highly resistant to intestinal proteases. In line with their dose-dependent function as co-stimulatory molecules in adaptive immunity of celiac disease, they appear to play a role in promoting other immune-mediated diseases within and outside the GI tract. Thus, ATIs may be prime candidates of severe forms of non-celiac gluten (wheat) sensitivity.

Testing safety of germinated rye sourdough in a celiac disease model based on the adoptive transfer of prolamin-primed memory T cells into lymphopenic mice.

UNLABELLED: The current treatment for celiac disease is strict gluten-free diet. Technical processing may render gluten-containing foods safe for consumption by celiac patients, but so far in vivo safety testing can only be performed on patients. We modified a celiac disease mouse model to test antigenicity and inflammatory effects of germinated rye sourdough, a food product characterized by extensive prolamin hydrolysis. Lymphopenic Rag1-/- or nude mice were injected with splenic CD4+CD62L-CD44high-memory T cells from gliadin- or secalin-immunized wild-type donor mice. We found that: 1) Rag1-/- recipients challenged with wheat or rye gluten lost more body weight and developed more severe histological duodenitis than mice on gluten-free diet. This correlated with increased secretion of IFNγ, IL-2, and IL-17 by secalin-restimulated splenocytes. 2) In vitro gluten testing using competitive R5 ELISA demonstrated extensive degradation of the gluten R5 epitope in germinated rye sourdough. 3) However, in nude recipients challenged with germinated rye sourdough (vs. native rye sourdough), serum anti-secalin IgG/CD4+ T helper 1-associated IgG2c titers were only reduced, but not eliminated. In addition, there were no reductions in body weight loss, histological duodenitis, or T cell cytokine secretion in Rag1-/- recipients challenged accordingly. IN CONCLUSION: 1) prolamin-primed CD4+CD62L-CD44high-memory T cells induce gluten-sensitive enteropathy in Rag1-/- mice. 2) Hydrolysis of secalins in germinated rye sourdough remains incomplete. Secalin peptides retain B and T cell stimulatory capacity and remain harmful to the intestinal mucosa in this celiac disease model. 3) Current antibody-based prolamin detection methods may fail to detect antigenic gluten fragments in processed cereal food products.

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.

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.

Wheat ATIs: Characteristics and Role in Human Disease.

Amylase/trypsin-inhibitors (ATIs) comprise about 2-4% of the total wheat grain proteins and may contribute to natural defense against pests and pathogens. However, they are currently among the most widely studied wheat components because of their proposed role in adverse reactions to wheat consumption in humans. ATIs have long been known to contribute to IgE-mediated allergy (notably Bakers' asthma), but interest has increased since 2012 when they were shown to be able to trigger the innate immune system, with attention focused on their role in coeliac disease which affects about 1% of the population and, more recently, in non-coeliac wheat sensitivity which may affect up to 10% of the population. This has led to studies of their structure, inhibitory properties, genetics, control of expression, behavior during processing, effects on human adverse reactions to wheat and, most recently, strategies to modify their expression in the plant using gene editing. We therefore present an integrated account of this range of research, identifying inconsistencies, and gaps in our knowledge and identifying future research needs. Note  This paper is the outcome of an invited international ATI expert meeting held in Amsterdam, February 3-5 2020.

Sourdough Fermentation Degrades Wheat Alpha-Amylase/Trypsin Inhibitor (ATI) and Reduces Pro-Inflammatory Activity.

The ingestion of gluten-containing foods can cause wheat-related disorders in up to 15% of wheat consuming populations. Besides the role of gluten, α-amylase/trypsin inhibitors (ATI) have recently been identified as inducers of an innate immune response via toll-like receptor 4 in celiac disease and non-celiac wheat sensitivity. ATI are involved in plant self-defense against insects and possibly in grain development. Notably, they are largely resistant to gastrointestinal proteases and heat, and their inflammatory activity affects not only the intestine, but also peripheral organs. The aim of this study was to understand the changes of ATI throughout the sourdough and yeast-fermented bread-making processes. ATI tetramers were isolated, fluorescein-labelled, and added to a mini-dough bread-making system. When the pH decreased below 4.0 in sourdough fermentation, the ATI tetramers were degraded due to the activation of aspartic proteases, whilst in yeast fermentation, ATI tetramers remained intact. The amylase inhibitory activity after sourdough fermentation decreased significantly, while the concentration of free thiol groups increased. The glutathione reductase activity of Fructilactobacillus sanfranciscensis did not contribute to the reduction of ATI tetramers. Compared to the unfermented wheat, sourdough fermentation was able to decrease the release of pro-inflammatory cytokines monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor alpha (TNF-α) in quantitative ATI extracts added to the human monocytic cell line THP-1. The current data suggest that sourdough fermentation can degrade ATI structure and bioactivity, and point to strategies to improve product development for wheat sensitivity patients.

The Overlapping Area of Non-Celiac Gluten Sensitivity (NCGS) and Wheat-Sensitive Irritable Bowel Syndrome (IBS): An Update.

Gluten-related disorders have recently been reclassified with an emerging scientific literature supporting the concept of non-celiac gluten sensitivity (NCGS). New research has specifically addressed prevalence, immune mechanisms, the recognition of non-immunoglobulin E (non-IgE) wheat allergy and overlap of NCGS with irritable bowel syndrome (IBS)-type symptoms. This review article will provide clinicians with an update that directly impacts on the management of a subgroup of their IBS patients whose symptoms are triggered by wheat ingestion.

Non-celiac wheat sensitivity: differential diagnosis, triggers and implications.

Non allergy-non-celiac wheat sensitivity (NCWS) has become a common and often overrated diagnosis. Skepticism mainly relates to patients with prominent intestinal symptoms in the absence of general or intestinal signs of inflammation. There is consensus that the major wheat sensitivities, celiac disease and wheat allergy, have to be ruled out which may be difficult for wheat allergy. The non-inflammatory intolerances to carbohydrates, mainly lactose and FODMAPs (fermentable oligi-, di-, monosaccharides and polyols), which cause bloating or diarrhoea, can usually be excluded clinically or by simple tests. Recent studies and experimental data strongly indicate that NCWS exists in a substantial proportion of the population, that it is an innate immune reaction to wheat and that patients often present with extraintestinal symptoms, such as worsening of an underlying inflammatory disease in clear association with wheat consumption. Wheat amylase-trypsin inhibitors (ATIs) have been identified as the most likely triggers of NCWS. They are highly protease resistant and activate the toll-like receptor 4 (TLR4) complex in monocytes, macrophages and dendritic cells of the intestinal mucosa. Non-gluten containing cereals or staples display no or little TLR4 stimulating activity. Wheat ATIs are a family of up to 17 similar proteins of molecular weights around 15 kD and represent 2-4% of the wheat protein. With oral ingestion they costimulate antigen presenting cells and promote T cell activation in celiac disease, but also in other immune-mediated diseases within and outside the GI tract.

Diagnosis of Non-Celiac Gluten Sensitivity (NCGS): The Salerno Experts' Criteria.

Non-Celiac Gluten Sensitivity (NCGS) is a syndrome characterized by intestinal and extra-intestinal symptoms related to the ingestion of gluten-containing food, in subjects that are not affected by either celiac disease or wheat allergy. Given the lack of a NCGS biomarker, there is the need for standardizing the procedure leading to the diagnosis confirmation. In this paper we report experts' recommendations on how the diagnostic protocol should be performed for the confirmation of NCGS. A full diagnostic procedure should assess the clinical response to the gluten-free diet (GFD) and measure the effect of a gluten challenge after a period of treatment with the GFD. The clinical evaluation is performed using a self-administered instrument incorporating a modified version of the Gastrointestinal Symptom Rating Scale. The patient identifies one to three main symptoms that are quantitatively assessed using a Numerical Rating Scale with a score ranging from 1 to 10. The double-blind placebo-controlled gluten challenge (8 g/day) includes a one-week challenge followed by a one-week washout of strict GFD and by the crossover to the second one-week challenge. The vehicle should contain cooked, homogeneously distributed gluten. At least a variation of 30% of one to three main symptoms between the gluten and the placebo challenge should be detected to discriminate a positive from a negative result. The guidelines provided in this paper will help the clinician to reach a firm and positive diagnosis of NCGS and facilitate the comparisons of different studies, if adopted internationally.