Luis Vaquero

Diversity of the cultivable human gut microbiome involved in gluten metabolism: isolation of microorganisms with potential interest for coeliac disease

Gluten, a common component in the human diet, is capable of triggering coeliac disease pathogenesis in genetically predisposed individuals. Although the function of human digestive proteases in gluten proteins is quite well known, the role of intestinal microbiota in the metabolism of proteins is frequently underestimated. The aim of this study was the isolation and characterisation of the human gut bacteria involved in the metabolism of gluten proteins. Twenty-two human faecal samples were cultured with gluten as the principal nitrogen source, and 144 strains belonging to 35 bacterial species that may be involved in gluten metabolism in the human gut were isolated. Interestingly, 94 strains were able to metabolise gluten, 61 strains showed an extracellular proteolytic activity against gluten proteins, and several strains showed a peptidasic activity towards the 33-mer peptide, an immunogenic peptide in patients with coeliac disease. Most of the strains were classified within the phyla Firmicutes and Actinobacteria, mainly from the genera Lactobacillus, Streptococcus, Staphylococcus, Clostridium and Bifidobacterium. In conclusion, the human intestine exhibits a large variety of bacteria capable of utilising gluten proteins and peptides as nutrients. These bacteria could have an important role in gluten metabolism and could offer promising new treatment modalities for coeliac disease.

Fecal gluten peptides reveal limitations of serological tests and food questionnaires for monitoring gluten-free diet in celiac disease patients

Objectives:Treatment for celiac disease (CD) is a lifelong strict gluten-free diet (GFD). Patients should be followed-up with dietary interviews and serology as CD markers to ensure adherence to the diet. However, none of these methods offer an accurate measure of dietary compliance. Our aim was to evaluate the measurement of gluten immunogenic peptides (GIP) in stools as a marker of GFD adherence in CD patients and compare it with traditional methods of GFD monitoring.Methods:We performed a prospective, nonrandomized, multicenter study including 188 CD patients on GFD and 84 healthy controls. Subjects were given a dietary questionnaire and fecal GIP quantified by enzyme-linked immunosorbent assay (ELISA). Serological anti-tissue transglutaminase (anti-tTG) IgA and anti-deamidated gliadin peptide (anti-DGP) IgA antibodies were measured simultaneously.Results:Of the 188 celiac patients, 56 (29.8%) had detectable GIP levels in stools. There was significant association between age and GIP in stools that revealed increasing dietary transgressions with advancing age (39.2% in subjects ≥13 years old) and with gender in certain age groups (60% in men ≥13 years old). No association was found between fecal GIP and dietary questionnaire or anti-tTG antibodies. However, association was detected between GIP and anti-DGP antibodies, although 46 of the 53 GIP stool-positive patients were negative for anti-DGP.Conclusions:Detection of gluten peptides in stools reveals limitations of traditional methods for monitoring GFD in celiac patients. The GIP ELISA enables direct and quantitative assessment of gluten exposure early after ingestion and could aid in the diagnosis and clinical management of nonresponsive CD and refractory CD. Trial registration number NCT02711397.

Manifestaciones gastrointestinales en pacientes con inmunodeficiencias primarias que cursan con déficit de anticuerpos

INTRODUCTION Primary immunodeficiencies can lead to gastrointestinal manifestations that are still not well defined. OBJECTIVE To analyze gastrointestinal manifestations associated with primary immunodeficiencies. MATERIAL AND METHODS We performed a retrospective study that included patients diagnosed with primary antibody deficiencies in a third-level hospital. The patients were divided into two groups: isolated IgA deficiency and common variable immunodeficiency syndrome (CVIS). The timing of presentation and type of gastrointestinal symptoms were analyzed. RESULTS There were 57 patients: 20 with CVIS (35%) and 37 with isolated IgA deficiency (65%). Diagnosis was made in the pediatric age in 17 patients, of whom 13 had isolated IgA deficiency. In 84% of the patients, diagnosis of immunodeficiency was made before the development of gastrointestinal manifestations. Digestive symptoms were found in 74% of the patients, the most frequent being diarrhea. In 46% of the patients, digestive disease was confirmed, mainly through endoscopy. Celiac-like lesions, chronic atrophic gastritis, ulcerative colitis-like disease and Crohns disease were more common in CVIS. In isolated IgA deficiency, Helicobacter pylori-positive chronic gastritis predominated. Mean age was significantly higher (36 vs. 24 years, p=0.02) and IgA titer significantly lower (17 vs. 34UI/ml; p=0.008) in patients with associated gastrointestinal disease. CONCLUSIONS Gastrointestinal symptoms are frequent and lead to endoscopic diagnosis in half of patients with primary immunodeficiencies. Ulcerative colitis, and celiac- and Crohns-like disease are atypical entities that occur in CVIS.

Coeliac disease screening in first-degree relatives on the basis of biopsy and genetic risk.

Background Serological markers of coeliac disease (CD) lack diagnostic value to identify mild histopathological lesions mainly in adults at risk of CD. Aims The aim of this study was to evaluate the usefulness of human leukocyte antigen (HLA)-DQ2/8 genotyping, followed by duodenal biopsy for the detection of CD in adult first-degree relatives (FDRs) of patients with CD. Materials and methods Ninety-two adult DQ2/8 positive FDRs were consecutively included. A duodenal biopsy was offered irrespective of the serology result or associated symptoms. The clinical features, associated autoimmune diseases and biochemical parameters were recorded. Results Sixty-seven FDRs (mean age 34 years) underwent a duodenal biopsy. Histopathological alterations were found in 32 (48%) and showed the following stages: 12 Marsh I (18%), one Marsh II (1.5%), four Marsh IIIA (6%), five Marsh IIIB (7.5%) and 10 Marsh IIIC (15%). Positive serological markers were present in 17/67 (25%), with only one showing Marsh I and the remainder presenting some degree of duodenal atrophy (Marsh III). In addition, 33/67 (54%) had gastrointestinal symptoms, with dyspepsia being the most prevalent. The distribution of symptoms, anaemia and autoimmune disease was independent of the duodenal histopathological stage. Serology-based screening would diagnose 50% of the cases showing any degree of CD spectrum and miss 6% of the cases with mucosal atrophy. Conclusion Adult FDRs of patients with CD can benefit from a screening strategy on the basis of HLA-DQ genotyping, followed by a duodenal biopsy. Gastrointestinal symptoms and lymphocytic enteritis are common findings that may benefit from a gluten-free diet.

Age-related differences in celiac disease: Specific characteristics of adult presentation.

Celiac disease may appear both in early childhood and in elderly subjects. Current knowledge of the disease has revealed some differences associated to the age of presentation. Furthermore, monitoring and prognosis of celiac subjects can vary depending on the pediatric or adult stage. The main objective of this review is to provide guidance for the adult diagnostic and follow-up processes, which must be tailored specifically for adults and be different from pediatric patients.

Revisión de las patologías relacionadas con la ingesta de gluten

Cereals are considered a basic food. Through the development of cooking, the human being has produced high- gluten-content food, so that it could make the most of its nutritional properties. Wheat is becoming one of the key elements of the Mediterranean diet. Amongst gluten- intake-related pathologies- gluten is present mainly in wheat, barley and rye- celiac disease (CD) is the most well-known. CD is a chronic inflammatory condition which affects gastrointestinal tract which develops in genetically predisposed individuals. The most common manifestation of CD is nutrients malabsorption. This protein trigger other pathology, wheat allergy (WA), which is an adverse immunological effect to gluten due to E immunoglobulin. A recent increased in non celiac gluten sensitivity (NCGS) has also been noticed, defined as the emergence of a range of gluten-intake related symptoms in patients for which celiac disease and wheat allergy have been ruled out. This article discusses these three conditions with their phatogenic mecanisms and the different clinic manifestations.

Linfoma intestinal de células T asociado a enteropatía y sin relación con enfermedad celíaca

Type II enteropathy-associated T-cell lymphoma (EATL) is an uncommon intestinal lymphoma. We report the case of a 73-year-old man with diarrhea and weight loss. Duodenal biopsy showed atrophy and infiltration of irregular lymphocytes. Immunohistochemistry was positive for CD3, CD8, and CD56 with monoclonal TCR rearrangement. The HLA-DQ genotype was DQ5/DQ9. The Epstein-Barr virus RNA test was negative. Before specific chemotherapy could be administered, the patient was admitted to hospital for a respiratory infection and died from a cause unrelated to his lymphoma. The differential diagnosis of CD56-positive lymphoproliferative processes include type II EATL, primary T-cell/natural killer-cell intestinal lymphoma and hepatosplenic T-cell lymphoma. The patient had CD8 y CD56+ markers that allowed type I EATL to be excluded. The HLA-DQ genotype did not correspond to celiac disease and the biopsy showed proliferation of lymphocytes with atypia. The primary intestinal T-cell/natural killer-cell lymphoma was characterized mainly by the absence of CD8 and monoclonal reassortment of the TCR present in this case.

The human digestive tract has proteases capable of gluten hydrolysis

Objective To identify, purify, and characterize the proteins responsible for glutenase activity in the feces of healthy subjects and patients with celiac disease (CD). Methods Sixteen subjects were included in this study; 8 were healthy with no known food intolerances, and 8 were treated CD patients on a gluten-free diet. Fecal samples were homogenized, and precipitated proteins were purified by chromatography. Glutenase activity was evaluated by bioassays, zymography, and high-performance liquid chromatography with immunogenic 33-mer, 19-mer, and 13-mer gliadin peptides. Results The gastrointestinal elastase 3B (CEL3B), elastase 2A (CEL2A), and carboxypeptidase A1 (CBPA1) enzymes degraded human gluten. These proteins fully hydrolyzed 13-mer and 19-mer gliadin peptides that trigger immune-mediated enteropathy in individuals genetically predisposed to CD and partially digested a 33-mer. Feces from patients with CD showed more glutenase activity than feces from individuals without CD (171–466% higher). Peptidase activity against the gliadin peptides also increased in patients with CD. Conclusion The digestive tracts of patients with CD and healthy subjects have enzymatic machinery needed for gluten degradation. Patients with CD showed more gluten hydrolysis than did healthy individuals, although, in both cases, a fraction of 33-mer peptide remained intact. Gliadin peptides derived from gastrointestinal digestion, especially the 33-mer, can potentially be used by commensal microbiota from both CD-positive and CD-negative individuals, and differences in bacterial hydrolysis can modify its immunogenic capacity.

Coeliac disease and gastrointestinal symptom screening in adult first-degree relatives

The first‐degree relatives (FDRs) of patients with coeliac disease are the main risk group for disease development. The study aims to evaluate the screening strategy in FDRs with negative coeliac serology based on human leukocyte antigen (HLA) genotyping, followed by duodenal biopsy, and to analyze the prevalence of gastrointestinal symptoms and the influence of gluten intake.

Gluten Metabolism in Humans: Involvement of the Gut Microbiota

Abstract Gluten proteins are the major storage proteins that are deposited in the starchy endosperm cells of developing wheat grain. These proteins have the capacity to form a viscoelastic network, and thus wheat is used in numerous processed foods. Therefore, a large amount of gluten protein is ingested by humans. However, because of their high proline and glutamine content, gluten peptides are relatively resistant to complete digestion by human digestive proteases because those enzymes are deficient in prolyl endopeptidasic activity. The incomplete digestion of gluten proteins generates high molecular weight oligopeptides that remain in the lumen of the small intestine; some of these are capable of triggering the inflammatory process associated with celiac disease (CD). Nevertheless, there are several reasons why gut microbiota should be taken into account when considering the metabolism of proteins in the human intestine. For example, there are bacteria in the oral cavity that have the ability to hydrolyze gluten peptides, and there are bacteria in the large intestine with the ability to digest gliadin peptides. These bacteria could generate different digestion processes for gluten proteins in CD patients and in healthy people. Therefore, this review examines gluten metabolism throughout the gastrointestinal tract, and the role of the gut microbiota in this process.Gluten proteins are the major storage proteins that are deposited in the starchy endosperm cells of developing wheat grain. These proteins have the capacity to form a viscoelastic network, and thus wheat is used in numerous processed foods. Therefore, a large amount of gluten protein is ingested by humans. However, because of their high proline and glutamine content, gluten peptides are relatively resistant to complete digestion by human digestive proteases because those enzymes are deficient in prolyl endopeptidasic activity. The incomplete digestion of gluten proteins generates high molecular weight oligopeptides that remain in the lumen of the small intestine; some of these are capable of triggering the inflammatory process associated with celiac disease (CD). Nevertheless, there are several reasons why gut microbiota should be taken into account when considering the metabolism of proteins in the human intestine. For example, there are bacteria in the oral cavity that have the ability to hydrolyze gluten peptides, and there are bacteria in the large intestine with the ability to digest gliadin peptides. These bacteria could generate different digestion processes for gluten proteins in CD patients and in healthy people. Therefore, this review examines gluten metabolism throughout the gastrointestinal tract, and the role of the gut microbiota in this process.