Pathomechanisms in celiac disease

A review of the auditory-gut-brain axis

Hearing loss places a substantial burden on medical resources across the world and impacts quality of life for those affected. Further, it can occur peripherally and/or centrally. With many possible causes of hearing loss, there is scope for investigating the underlying mechanisms involved. Various signaling pathways connecting gut microbes and the brain (the gut-brain axis) have been identified and well established in a variety of diseases and disorders. However, the role of these pathways in providing links to other parts of the body has not been explored in much depth. Therefore, the aim of this review is to explore potential underlying mechanisms that connect the auditory system to the gut-brain axis. Using select keywords in PubMed, and additional hand-searching in google scholar, relevant studies were identified. In this review we summarize the key players in the auditory-gut-brain axis under four subheadings: anatomical, extracellular, immune and dietary. Firstly, we identify important anatomical structures in the auditory-gut-brain axis, particularly highlighting a direct connection provided by the vagus nerve. Leading on from this we discuss several extracellular signaling pathways which might connect the ear, gut and brain. A link is established between inflammatory responses in the ear and gut microbiome-altering interventions, highlighting a contribution of the immune system. Finally, we discuss the contribution of diet to the auditory-gut-brain axis. Based on the reviewed literature, we propose numerous possible key players connecting the auditory system to the gut-brain axis. In the future, a more thorough investigation of these key players in animal models and human research may provide insight and assist in developing effective interventions for treating hearing loss.

Mechanisms by which gut microorganisms influence food sensitivities

Finely tuned mechanisms enable the gastrointestinal tract to break down dietary components into nutrients without mounting, in the majority of cases, a dysregulated immune or functional host response. However, adverse reactions to food have been steadily increasing, and evidence suggests that this process is environmental. Adverse food reactions can be divided according to their underlying pathophysiology into food intolerances, when, for instance, there is deficiency of a host enzyme required to digest the food component, and food sensitivities, when immune mechanisms are involved. In this Review, we discuss the clinical and experimental evidence for enteric infections and/or alterations in the gut microbiota in inciting food sensitivity. We focus on mechanisms by which microorganisms might provide direct pro-inflammatory signals to the host promoting breakdown of oral tolerance to food antigens or indirect pathways that involve the metabolism of protein antigens and other dietary components by gut microorganisms. Better understanding of these mechanisms will help in the development of preventive and therapeutic strategies for food sensitivities.

Non-Celiac Gluten Sensitivity: How Its Gut Immune Activation and Potential Dietary Management Differ from Celiac Disease

Non-celiac gluten sensitivity (NCGS) is a clinical entity triggered by the ingestion of gluten-containing grains leading to intestinal and/or extraintestinal symptoms that resolve once the gluten-containing foodstuff is eliminated from the diet, and it is diagnosed when celiac disease (CD) and wheat allergy (WA) have been ruled out. The limited knowledge about the pathophysiology of NCGS and the lack of validated biomarkers are still major limitations for clinical studies, making it difficult to differentiate NCGS from other gluten-related disorders (GRD). In the absence of clear-cut diagnostic criteria, NCGS is still mainly a diagnosis of exclusion. Several studies suggest that NCGS is an immune-mediated disease that likely activates an innate immune response. Moreover, it has recently been hypothesized that in addition to gluten, other components of wheat may be responsible for the symptoms observed in individuals without CD. This review aims at discussing available evidence related to the histological and immunological features in the gut mucosa of patients with NCGS and at outlining new dietary opportunities for these patients.

Physiopathology and Management of Gluten-Induced Celiac Disease

Proline- and glutamine-rich gluten proteins are one of the major constituents of cereal dietary proteins, which are largely resistant to complete cleavage by the human gastrointestinal (GI) digestive enzymes. Partial digestion of gluten generates approximately 35 amino acids (aa) immunomodulatory peptides which activate T-cell-mediated immune system, followed by immunological inflammation of mucosa leading to the onset of celiac disease (CD). CD is an autoimmune disease associated with HLA-DQ2/DQ8 polymorphism and dysbiosis of gut microbiota. CD is either diagnosed using duodenal mucosal biopsis or serological testing for transglutaminase 2 (TG2) specific antibodies (IgA and IgG). Current therapy for CD management is gluten-free diet, while other therapies like glutenase, probiotics, immunomodulation, jamming of HLA-DQ2, inhibition of TG2, and gluten tolerance aided by gluten tolerizing vaccines are being developed.

Molecular diversity of α-gliadin expressed genes in genetically contrasted spelt (Triticum aestivum ssp. spelta) accessions and comparison with bread wheat (T. aestivum ssp. aestivum) and related diploid Triticum and Aegilops species

The gluten proteins of cereals such as bread wheat (Triticum aestivum ssp. aestivum) and spelt (T. aestivum ssp. spelta) are responsible for celiac disease (CD). The α-gliadins constitute the most immunogenic class of gluten proteins as they include four main T-cell stimulatory epitopes that affect CD patients. Spelt has been less studied than bread wheat and could constitute a source of valuable diversity. The objective of this work was to study the genetic diversity of spelt α-gliadin transcripts and to compare it with those of bread wheat. Genotyping data from 85 spelt accessions obtained with 19 simple sequence repeat (SSR) markers were used to select 11 contrasted accessions, from which 446 full open reading frame α-gliadin genes were cloned and sequenced, which revealed a high allelic diversity. High variations among the accessions were highlighted, in terms of the proportion of α-gliadin sequences from each of the three genomes (A, B and D), and their composition in the four T-cell stimulatory epitopes. An accession from Tajikistan stood out, having a particularly high proportion of α-gliadins from the B genome and a low immunogenic content. Even if no clear separation between spelt and bread wheat sequences was shown, spelt α-gliadins displayed specific features concerning e.g. the frequencies of some amino acid substitutions. Given this observation and the variations in toxicity revealed in the spelt accessions in this study, the high genetic diversity held in spelt germplasm collections could be a valuable resource in the development of safer varieties for CD patients.

Atrial Electromechanical Properties in Coeliac Disease

BACKGROUND

Coeliac disease (CD) is an autoimmune and inflammatory disorder of the small intestine. There is reasonable evidence linking inflammation to the initiation and continuation of atrial fibrillation (AF) in inflammatory conditions. Atrial electro-mechanic delay (EMD) was suggested as an early marker of AF in previous studies. The objectives of this study were to evaluate atrial electromechanical properties measured by tissue Doppler imaging and simultaneous electrocardiography (ECG) tracing in patients with CD.

METHODS

Thirty-nine patients with coeliac disease (CD), and 26 healthy volunteers, matched for age and sex, were enrolled in the study. Atrial electromechanical properties were measured by using transthoracic echocardiography and surface ECG. Interatrial electro-mechanic delay (EMD), left intraatrial EMD, right intratrial EMD were calculated.

RESULTS

There was no difference between CD patients and healthy volunteers in terms of basal characteristics. Patients with CD had significantly prolonged left and right intraatrial EMDs, and interatrial EMD compared to healthy controls (p= 0.03, p= 0.02, p<0.0001, respectively). Interatrial EMD was positively correlated with age, disease duration, anti-gliadin IgG, anti-endomysium and disease status. In multiple linear regression, interatrial EMD was independently associated with disease duration, anti-endomysium and disease status after adjusting for age and sex.

CONCLUSIONS

In the present study, atrial EMDs were found significantly higher in patients with CD compared with healthy individuals. Measurement of atrial EMD parameters might be used to predict the risk of development of AF in patients with CD.

Proximal muscle weakness as a result of osteomalacia associated with celiac disease: a case report

A 24-year-old woman suffering from back and hip pain with difficulty in walking was reported. She had proximal muscle weakness. Laboratory findings led to the diagnosis of osteomalacia. Positivity of antibodies strengthened suspicion of celiac disease. In patients with proximal muscle weakness, osteomalacia should be considered in differential diagnosis even in a young woman.

INTRODUCTION

A 24-year-old woman suffering from back pain, bilateral hip pain, and difficulty in walking was reported. Her symptoms had started in the first trimester of pregnancy.

METHODS

In her physical examination, proximal muscle weakness and waddling gait pattern were determined. Her lumbar spine and hip MRI revealed no obvious pathological findings. Electromyography showed a myophatic pattern.

RESULTS

Physical examination, normal values of creatine kinase, and muscle biopsy were supplied to exclude the diagnosis of primer muscle diseases. Laboratory findings led to the diagnosis of osteomalacia with normal renal function. Gastrointestinal symptoms and positivity of anti-gliadin and anti-endomysium antibodies strengthened the suspicion of celiac disease as a cause of the osteomalacia. The diagnosis of celiac disease was confirmed with duodenal mucosal biopsy.

CONCLUSION

In patients with proximal muscle weakness and waddling gait pattern, osteomalacia should be considered in differential diagnosis even in a young woman and underlying disease should be investigated.

Celiac disease: role of intestinal compartments in the mucosal immune response

Different approaches have been used to study the pattern of cytokines in celiac disease (CD). Laser capture microdissection (LCM) is a powerful tool for the isolation of specific tissue compartments. We aimed to investigate the mucosal immune response that takes place in different intestinal compartments of CD patients, dissected by LCM, analyzing cytokine expression profile. Frozen section of jejunum was obtained from 15 untreated CD and 15 control. Surface epithelium and lamina propria compartment were isolated by LCM. RNA from each LCM sample was extracted and, after a retrotranscription step, messenger RNA levels for MxA, IL-15, TNF-α, IFN-γ, IL-17α, IL-21, IL-10, and TGF-β were determined by quantitative reverse transcriptase-PCR. Increased gene expression levels of MxA, IL-15, TNF-α, IL-10, and TGF-β was observed in the surface epithelium of untreated CD with respect to control. Furthermore, all the cytokines investigated were upregulated in the lamina propria of untreated CD as compared to control. Within the untreated CD group the expression of IL-15 was higher, in the surface epithelium than in the lamina propria, whereas the expression levels of IL-17 and IL-21 were higher in the lamina propria than in the surface epithelium. Finally, high levels of IL-10 and TGF-β were detected in both compartments of untreated CD biopsies. In CD, surface epithelium and lamina propria compartments, play a prominent role in determining innate and adaptive immunity, respectively. Conversely, surface epithelium and lamina propria produce high levels of anti-inflammatory cytokines, suggesting that both compartments are involved in the immunoregulatory response.

Association of maternal education, early infections, and antibiotic use with celiac disease: a population-based birth cohort study in northeastern Italy

We conducted a population-based birth cohort study of approximately 203,000 babies born in northeastern Italy (1989-2012) to investigate perinatal variables, early infections leading to hospital admission, and antibiotic use in the first 12 months of life as possible risk factors for celiac disease (CD). Incident CD cases were identified from pathology reports, hospital discharge records, and exemptions from prescription charges for clinical tests. Multivariate Poisson regression models were fitted to estimate incidence rate ratios (IRRs). A total of 1,227 children had CD; CD was histopathologically confirmed in 866 (71%). Female sex, maternal age, and high maternal educational level were found to be significantly associated with CD. Gastrointestinal infections were strongly associated with a subsequent diagnosis of CD (IRR = 2.04, 95% confidence interval (CI): 1.30, 3.22). Antibiotic use was significantly associated with CD onset (IRR = 1.24, 95% CI: 1.07, 1.43), with a dose-response relationship for number of courses (P-trend < 0.01). Cephalosporin use strongly increased the risk of CD (IRR = 1.42, 95% CI: 1.18, 1.73). Use of antibiotics (supported by the dose-response relationship) and gastrointestinal infections in the first year of life may facilitate the early onset of CD by altering intestinal microflora and the gut mucosal barrier. Perinatal factors, including cesarean section, had little influence on the risk of childhood CD.

Gliadin activates arginase pathway in RAW264.7 cells and in human monocytes

Celiac disease (CD) is an autoimmune enteropathy triggered in susceptible individuals by the ingestion of gliadin-containing grains. Recent studies have demonstrated that macrophages play a key role in the pathogenesis of CD through the release of inflammatory mediators such as cytokines and nitric oxide (NO). Since arginine is the obliged substrate of iNOS (inducible nitric oxide synthase), the enzyme that produces large amount of NO, the aim of this work is to investigate arginine metabolic pathways in RAW264.7 murine macrophages after treatment with PT-gliadin (PTG) in the absence and in the presence of IFNγ. Our results demonstrate that, besides strengthening the IFNγ-dependent activation of iNOS, gliadin is also an inducer of arginase, the enzyme that transforms arginine into ornithine and urea. Gliadin treatment increases, indeed, the expression and the activity of arginase, leading to the production of polyamines through the subsequent induction of ornithine decarboxylase. This effect is strengthened by IFNγ. The activation of these pathways takes advantage of the increased availability of arginine due to a decreased system y(+)l-mediated efflux, likely ascribable to a reduced expression of Slc7a6 transporter. A significant induction of arginase expression is also observed in human monocytes from healthy subject upon treatment with gliadin, thus demonstrating that gluten components trigger changes in arginine metabolism in monocyte/macrophage cells.

Early feeding and risk of celiac disease in a prospective birth cohort

OBJECTIVES

Timing of gluten introduction has been associated with the risk of celiac disease (CD) in children, but the optimal time window is unknown. We aimed to study the effect of age of gluten introduction on the risk of CD, adjusting for continued breastfeeding.

METHODS

In The Norwegian Mother and Child Cohort Study, a prospective birth cohort including 107,000 children, CD was identified by questionnaires and by linkage to the Norwegian Patient Register. Gluten introduction was reported monthly from 0 to 6 months of age, and breastfeeding from 0 to 18 months.

RESULTS

After exclusion of cases with insufficient information, 324 children with CD in a cohort of 82,167 were used in the analyses. Gluten was introduced before or at 4 months in 8.0%, 5 to 6 months in 45.3%, and after 6 months in 46.6%, whereas continued breastfeeding was stable at ≈ 78% at 6 months age. CD was diagnosed in 3.68/1000 of the infants with gluten introduction at 5 to 6 months compared with 4.15/1000 with late and 4.24/1000 with early gluten introduction. After adjustment for the child's age and gender, breastfeeding, and maternal CD, delayed gluten introduction was associated with an increased risk of CD (adjusted odds ratio, 1.27 [95% confidence interval, 1.01-1.65], P = .045). Breastfeeding >12 months was also associated with increased risk (adjusted odds ratio, 1.49 [95% confidence interval, 1.01-2.21], P = .046).

CONCLUSIONS

We found an increased risk of CD in children introduced to gluten after 6 months and a higher risk in children breastfed after 12 months age.

Immunohistochemical stains for CD3 and CD8 do not improve detection of gluten-sensitive enteropathy in duodenal biopsies

Patients with gluten-sensitive enteropathy usually have increased numbers of duodenal intraepithelial lymphocytes even if the villous architecture is normal. Some authors advocate the use of CD8 and CD3 immunohistochemical stains to improve detection of intraepithelial lymphocytosis, yet the added value of immunohistochemistry when biopsies appear normal remains unproven. The purpose of this study was to evaluate the utility of CD3 and CD8 immunostains in detecting intraepithelial lymphocytosis among duodenal biopsies originally interpreted to be normal based on routine evaluation. We identified 200 duodenal biopsies from 172 patients, all of which were accompanied by a clinical question of gluten-sensitive enteropathy. Five well-oriented villi from each biopsy were assessed. Intraepithelial lymphocytes present in hematoxylin and eosin (H&E)-stained slides were counted and compared with the number of CD3 and CD8 immunopositive cells present in the villous epithelium. Results were expressed as the mean number of intraepithelial lymphocytes or immunopositive cells present per 20 villous tip enterocytes. Review of H&E-stained slides revealed a mean of 2.1 ± 0.1 intraepithelial lymphocytes, compared with 3.2 ± 0.1 CD3-positive and 2.1 ± 0.1 CD8-positive intraepithelial cells (P=<0.001 and 1, respectively), although none of the cases displayed sufficient numbers of intraepithelial lymphocytes to be considered abnormal (ie, ≥ 12/20 enterocytes) by any method. The number of intraepithelial lymphocytes detected by H&E evaluation or immunohistochemistry did not correlate with results of serologic studies for markers of gluten sensitivity. We conclude that immunostains for T cell markers do not improve detection of gluten-sensitive enteropathy when H&E-stained sections are normal.

Duodenal-mucosal bacteria associated with celiac disease in children

Celiac disease (CD) is an immune-mediated enteropathy triggered by the ingestion of cereal gluten proteins. This disorder is associated with imbalances in the gut microbiota composition that could be involved in the pathogenesis of CD. The aim of this study was to characterize the composition and diversity of the cultivable duodenal mucosa-associated bacteria of CD patients and control children. Duodenal biopsy specimens from patients with active disease on a gluten-containing diet (n = 32), patients with nonactive disease after adherence to a gluten-free diet (n = 17), and controls (n = 8) were homogenized and plated on plate count agar, Wilkins-Chalgren agar, brain heart agar, or yeast, Casitone, and fatty acid agar. The isolates were identified by partial 16S rRNA gene sequencing. Renyi diversity profiles showed the highest diversity values for active CD patients, followed by nonactive CD patients and control individuals. Members of the phylum Proteobacteria were more abundant in patients with active CD than in the other child groups, while those of the phylum Firmicutes were less abundant. Members of the families Enterobacteriaceae and Staphylococcaceae, particularly the species Klebsiella oxytoca, Staphylococcus epidermidis, and Staphylococcus pasteuri, were more abundant in patients with active disease than in controls. In contrast, members of the family Streptococcaceae were less abundant in patients with active CD than in controls. Furthermore, isolates of the Streptococcus anginosus and Streptococcus mutans groups were more abundant in controls than in both CD patient groups, regardless of inflammatory status. The findings indicated that the disease is associated with the overgrowth of possible pathobionts that exclude symbionts or commensals that are characteristic of the healthy small intestinal microbiota.

Celiac disease and gluten-free diet

Celiac disease is an autoimmunity inflammatory disorder of the small intestine caused by the ingestion of gluten in genetically predisposed individuals. The prevalence of the disorder is around 1 % of the Western population and is still increasing. The symptoms of celiac disease include chronic abdominal pain, diarrhoea, and growth retardation in children, and chronic fatigue and headache, bowel complaints, reduced fertility, dermatitis herpetiformis, osteoporosis, nerve and brain disorders, increasing risk of intestinal cancer. The clinical diagnosis of the disease is based on the serological tests and bowel biopsy. The treatment is a long-life gluten-free diet. It is necessary exclude from the diet wheat, rye, barley and probably oats and buckwheat and their products. The novel approaches for celiac disease are focused on the genetic manipulation of nontoxic gluten proteins, enzyme therapy, immune modulation, and induction of oral tolerance to gluten.

Extracellular matrix proteins and displacement of cultured fibroblasts from duodenal biopsies in celiac patients and controls

BACKGROUND

Celiac disease (CD) is mainly characterised by villous atrophy and mucosal architectural rearrangement. The fibroblasts (FBs) are the most abundant mesenchymal cell type in the intestinal mucosa and are responsible for both the architectural arrangement of the villi and the formation of the extracellular matrix (ECM). This study aimed at the evaluation of both the intracellular distribution of different proteins involved in ECM and FBs characterisation, and the cellular displacement of primary FBs obtained from duodenal endoscopic biopsies of healthy subjects and celiac patients.

METHODS

Primary healthy and celiac duodenal FBs were evaluated by means of immuno-fluorescence assay for collagen type I and IV, fibronectin, actin, alpha-Smooth Muscle Actin (alpha-SMA), Fibroblast Surface Protein (FSP) and transglutaminase type 2 (TG2). The geometric indexes of the fluorescence signals were investigated by image analysis software (Image J, NIH). Both morphology and kinetic were evaluated during a 72 hours time course movie. TG2 medium activity was evaluated by means of ELISA.

RESULTS

All the cells examined were immunopositive for FSP, alpha-SMA, actin, collagen I, collagen IV and TG2. CD cells showed a signet collagen-I and collagen-IV pattern, as compared to the controls being characterised by a spindle geometry. Moreover, the collagen signals in CD FBs showed a significantly higher circularity index (major orthogonal diameter ratio) than the controls (p<0.0001), whereas the perimeter and area ratio were significantly lower (p<0.0001). The TG2 signal had a decreased area (p<0.05), but a two-fold increased medium activity. The time course highlighted a reduction of the displacement of CD FBs.

CONCLUSIONS

The isolated primary CD FBs showed a different collagen and TG2 pattern of distribution associated with a different cellular displacement. The reasons for such CD cell peculiar characteristics are yet unknown but they might represent a factor in the progression of the intestinal damage.

Molecular diagnosis of celiac disease: are we there yet?

BACKGROUND

Celiac disease (CD) is a complex genetic disorder of the small intestine resulting from aberrant cellular responses to gluten peptides. It may affect as much as 1% of the Western population and the only treatment is a lifelong gluten-free diet. Allelic variants of the HLA-DQ locus, coding for the HLA-DQ2 and HLA-DQ8 molecules, contribute to ∼ 40% of CD etiology, whereas other genes, such as MYO9B, CTLA4, IL2, IL21, PARD3 and MAGI2, have only a modest effect. Most of these genes have shown varied association among different populations and an overlap with other autoimmune or inflammatory disorders, indicating that such disorders may share common pathways.

OBJECTIVES

In this review, a molecular approach into diagnostics of celiac disease is shown.

CONCLUSIONS

Genome-wide association studies will allow more genes to be identified, and knowing how risk variants combine will help to predict better the risk for the individual. HLA typing can already be used to identify high-risk individuals.

Celiac disease, inflammation and oxidative damage: a nutrigenetic approach

Celiac disease (CD), a common heritable chronic inflammatory condition of the small intestine caused by permanent intolerance to gluten/gliadin (prolamin), is characterized by a complex interplay between genetic and environmental factors. Developments in proteomics have provided an important contribution to the understanding of the biochemical and immunological aspects of the disease and the mechanisms involved in toxicity of prolamins. It has been demonstrated that some gliadin peptides resistant to complete proteolytic digestion may directly affect intestinal cell structure and functions by modulating gene expression and oxidative stress. In recent years, the creation of the two research fields Nutrigenomics and Nutrigenetics, has enabled the elucidation of some interactions between diet, nutrients and genes. Various dietary components including long chain ω-3 fatty acids, plant flavonoids, and carotenoids have been demonstrated to modulate oxidative stress, gene expression and production of inflammatory mediators. Therefore their adoption could preserve intestinal barrier integrity, play a protective role against toxicity of gliadin peptides and have a role in nutritional therapy of celiac disease.

Lipid peroxidation and paraoxonase-1 activity in celiac disease

Paraoxonase-1 (PON1) plays an antioxidant and anti-inflammatory role. Aim of the study was to investigate the alteration of paraoxonase-1 activity in celiac disease (CD), an intestinal disorder characterized by toxic injury exerted by gluten peptides. Activities of PON1, levels of biochemical markers of lipid peroxidation and total antioxidant capacity were evaluated in serum obtained from 27 celiac patients (11 at diagnosis, 16 treated with gluten free diet) and 25 healthy subjects. Moreover, the serum susceptibility of Cu²⁺-induced lipid peroxidation was investigated in controls and patients. The results showed a lower PON1 activity in serum of both groups of celiac patients with respect to control subjects. PON1 activity in CD was related with markers of disease severity and was negatively correlated with the levels of lipid hydroperoxide and with the susceptibility of serum to lipid peroxidation induced in vitro by metal ions. The alteration of PON1 activity and markers of lipid peroxidation realized at lower extent in patients who were on a gluten-free diet.

Identification of Rothia bacteria as gluten-degrading natural colonizers of the upper gastro-intestinal tract

Background

Gluten proteins, prominent constituents of barley, wheat and rye, cause celiac disease in genetically predisposed subjects. Gluten is notoriously difficult to digest by mammalian proteolytic enzymes and the protease-resistant domains contain multiple immunogenic epitopes. The aim of this study was to identify novel sources of gluten-digesting microbial enzymes from the upper gastro-intestinal tract with the potential to neutralize gluten epitopes.

Methodology/Principal Findings

Oral microorganisms with gluten-degrading capacity were obtained by a selective plating strategy using gluten agar. Microbial speciations were carried out by 16S rDNA gene sequencing. Enzyme activities were assessed using gliadin-derived enzymatic substrates, gliadins in solution, gliadin zymography, and 33-mer α-gliadin and 26-mer γ-gliadin immunogenic peptides. Fragments of the gliadin peptides were separated by RP-HPLC and structurally characterized by mass spectrometry. Strains with high activity towards gluten were typed as Rothia mucilaginosa and Rothia aeria. Gliadins (250 µg/ml) added to Rothia cell suspensions (OD₆₂₀ 1.2) were degraded by 50% after ∼30 min of incubation. Importantly, the 33-mer and 26-mer immunogenic peptides were also cleaved, primarily C-terminal to Xaa-Pro-Gln (XPQ) and Xaa-Pro-Tyr (XPY). The major gliadin-degrading enzymes produced by the Rothia strains were ∼70–75 kDa in size, and the enzyme expressed by Rothia aeria was active over a wide pH range (pH 3–10).

Conclusion/Significance

While the human digestive enzyme system lacks the capacity to cleave immunogenic gluten, such activities are naturally present in the oral microbial enzyme repertoire. The identified bacteria may be exploited for physiologic degradation of harmful gluten peptides.

New screening tests enrich anti-transglutaminase results and support a highly sensitive two-test based strategy for celiac disease diagnosis

BACKGROUND

The identification of specific serological algorithms allowing the diagnosis of celiac disease (CD) is a new challenge for both the clinic and the laboratory. We compared the diagnostic accuracy of three new tests proposed for CD screening with that of the well established IgA tTG, and ascertained whether any combination of these tools might enhance accuracy in diagnosing CD.

METHODS

In sera from 329 CD and 374 control children, the following were assayed: IgA tTG; IgA/IgG, which identify tTG-gliadin complexes (Aeskulisa Celi Check and CeliCheck IgGA); IgA/IgG, which identify deamidated gliadin peptides and tTG (QUANTA Lite(TM) h-tTG/DGP Screen).

RESULTS

When specificity was set at 100%, the most sensitive index of CD was IgA tTG (75.7%, cut-off=100U), followed by QUANTA Lite(TM) h-tTG/DGP Screen (65.3%, cut-off 145U), Aeskulisa Celi Check (62.6%, cut-off 909U/mL) and CeliCheck IgGA (59.6%, cut-off 977U/mL). Three algorithms were obtained by combining IgA tTG with each of the new tests. The algorithm obtained by measuring IgA tTG and QUANTA Lite(TM) h-tTG/DGP Screen allowed the correct identification of CD in 78.7% of cases (negative predictive value=97.3%).

CONCLUSIONS

The two-test based strategy could be used for the cost effective diagnosis of CD.

Docosahexaenoic acid modulates in vitro the inflammation of celiac disease in intestinal epithelial cells via the inhibition of cPLA2

BACKGROUND & AIMS

The cytosolic phospolypase A(2) (cPLA(2)) - dependent release of arachidonic acid (AA) from the intra-epithelial lymphocytes plays a pivotal role in arming lymphocytes to cytolysis in the immune response of celiac disease. However, little is known about the role of enterocytes in releasing AA. Docosahexaenoic acid (DHA) is a long chain polyunsaturated fatty acid that counteracts many of the proinflammatory effect of AA. The aims of the present work were to evaluate if: 1) intestinal epithelial cells have a role in the celiac inflammation, releasing AA, and 2) if DHA is able to modulate the celiac inflammation, down-regulating the release of AA.

METHODS

A human intestinal epithelial cell line (Caco-2) was exposed to gliadin peptides (PT-gl) (500 μg/ml) and DHA (2 μg/ml), both alone and simultaneously up to 24 h.

RESULTS

The exposure of those cells to PT-gl alone resulted in an increased AA release, cycloxygenase-2 expression, cPLA(2) activity and prostaglandin E(2) and interleukin-8 release in culture medium, whereas the simultaneous exposure of the cells to DHA and PT-gl prevented the above-mentioned increases.

CONCLUSIONS

These results suggest that intestinal epithelial cells sustain the celiac inflammation, releasing AA when stimulated with gliadin and that DHA inhibits the AA release by these cells.

Discovery of a novel and rich source of gluten-degrading microbial enzymes in the oral cavity

Background

Celiac disease is a T cell mediated-inflammatory enteropathy caused by the ingestion of gluten in genetically predisposed individuals carrying HLA-DQ2 or HLA-DQ8. The immunogenic gliadin epitopes, containing multiple glutamine and proline residues, are largely resistant to degradation by gastric and intestinal proteases. Salivary microorganisms however exhibit glutamine endoprotease activity, discovered towards glutamine- and proline-rich salivary proteins. The aim was to explore if gliadins can serve as substrates for oral microbial enzymes.

Methodology/Principal Findings

Proteolytic activity in suspended dental plaque was studied towards a) gliadin-derived paranitroanilide(pNA)-linked synthetic enzyme substrates b) a mixture of natural gliadins and c) synthetic highly immunogenic gliadin peptides (33-mer of α2-gliadin and 26-mer of γ-gliadin). In addition, gliadin zymography was conducted to obtain the approximate molecular weights and pH activity profiles of the gliadin-degrading oral enzymes and liquid iso-electric focusing was performed to establish overall enzyme iso-electric points. Plaque bacteria efficiently hydrolyzed Z-YPQ-pNA, Z-QQP-pNA, Z-PPF-pNA and Z-PFP-pNA, with Z-YPQ-pNA being most rapidly cleaved. Gliadin immunogenic domains were extensively degraded in the presence of oral bacteria. Gliadin zymography revealed that prominent enzymes exhibit molecular weights >70 kD and are active over a broad pH range from 3 to 10. Liquid iso-electric focusing indicated that most gliadin-degrading enzymes are acidic in nature with iso-electric points between 2.5 and 4.0.

Conclusions/Significance

This is the first reported evidence for gluten-degrading microorganisms associated with the upper gastro-intestinal tract. Such microorganisms may play a hitherto unappreciated role in the digestion of dietary gluten and thus protection from celiac disease in subjects at risk.

Imaging analysis of the gliadin direct effect on tight junctions in an in vitro three-dimensional Lovo cell line culture system

Tight junctions play a pivotal role in maintaining the integrity of the intestinal barrier. Their alteration is involved in the pathogenesis of celiac disease. Our aim was to investigate the gliadin effect on the tight junction proteins in an in vitro three-dimensional cell culture model through imaging analyses. Lovo multicellular spheroids were treated with enzymatically digested (PT) gliadin 500 μg/mL and its effect on actin, occludin and zonula occludens-1, was evaluated by means of confocal laser microscopy, transmission electron microscopy and image capture analysis. Compared to untreated spheroids, PT-gliadin-treated ones showed enlargement of the paracellular spaces (9.0±6.9 vs. 6.2±1.7 nm, p<0.05) at transmission electron microscopy and tight junction protein alterations at confocal microscopy and image analyses. In untreated cell cultures thickness of the fluorescence contour of actin, zonula occludens-1 and occludin appeared significantly larger and more intense than in the treated ones. In occludin planimetric analysis the lengths of the integral uninterrupted cellular contour appeared longer in untreated than in PT-gliadin treated spheroids (71.8±42.8 vs. 23.4±25.9 μm, p<0.01). Our data demonstrated that tight junction proteins are directly damaged by gliadin as shown by means of quantitative imaging analysis.

Antibodies against deamidated gliadin peptides identify adult coeliac disease patients negative for antibodies against endomysium and tissue transglutaminase

BACKGROUND

This study was done to evaluate the diagnostic utility of antibodies against deamidated gliadin peptides compared to traditional markers for coeliac disease.

AIM

To evaluate diagnostic utility of antibodies against deamidated gliadin peptide (DGP).

METHODS

Sera from 176 adults, referred for endoscopy without previous analysis of antibodies against tissue transglutaminase (tTG) or endomysium (EmA), were retrospectively analysed by ELISAs detecting IgA/IgG antibodies against DGP or a mixture of DGP and tTG, and compared with IgA-tTG and EmA. Seventy-nine individuals were diagnosed with coeliac disease.

RESULTS

Receiver operating characteristic analyses verified the manufacturers' cut-off limits except for IgA/IgG-DGP/tTG. In sera without IgA deficiency, the sensitivity was higher for IgA/IgG-DGP (0.85-0.87) compared with IgA-tTg (0.76) and EmA (0.61). All tests showed high specificity (0.95-1.00). Eighteen coeliac disease-sera were negative regarding IgA-tTG, nine of which were positive for IgA/IgG-DGP. Sera from coeliac disease-patients >70 years were more often negative for IgA-tTG (50%) and IgA/IgG-DGP (36%) than younger patients (15% and 8% respectively) (P < 0.01). Three of the four IgA-deficient patients were positive in the IgA/IgG-DGP assay.

CONCLUSIONS

In this study of patients unselected regarding IgA-tTg/EmA, thus unbiased in this respect, IgA/IgG-DGP identified adult coeliac disease patients negative for antibodies against endomysium and tissue transglutaminase. Serology is often negative in elderly patients with coeliac disease; a small bowel biopsy should therefore be performed generously before coeliac disease is excluded.

Infectious disease and risk of later celiac disease in childhood

OBJECTIVE

The goal was to examine whether parent-reported infection at the time of gluten introduction increases the risk of future celiac disease (CD).

METHODS

Through the population-based All Infants in Southeast Sweden study, parents recorded data on feeding and infectious disease prospectively. Complete data on gluten introduction and breastfeeding duration were available for 9408 children. Those children had 42 826 parent-reported episodes of infectious disease in the first year of life (including 4003 episodes of gastroenteritis). We identified 44 children with biopsy-verified CD diagnosed after 1 year of age, and we used Cox regression to estimate the risk of future CD for children with infection at gluten introduction.

RESULTS

Eighteen children with CD (40.9%) had an infection at the time of gluten introduction, compared with 2510 reference individuals (26.8%; P = .035). Few children had gastroenteritis at the time of gluten introduction (1 child with CD [2.3%] vs 166 reference individuals [1.8%]; P = .546). With adjustment for age at gluten introduction and breastfeeding duration, we found no association between a future diagnosis of CD and either any infection (adjusted hazard ratio: 1.8 [95% confidence interval: 0.9-3.6]) or gastroenteritis (adjusted hazard ratio: 2.6 [95% confidence interval: 0.2-30.8]) at the time of gluten introduction. We found no associations between breastfeeding duration, age at gluten introduction, and future CD.

CONCLUSION

These results indicate that parent-reported infection at the time of gluten introduction is not a major risk factor for CD.

Dietary factors in chronic inflammation: food tolerances and intolerances of a New Zealand Caucasian Crohn's disease population

Diet is known to play a major role in the symptoms of the inflammatory bowel disease, Crohn's disease (CD). Although no single diet is appropriate to all individuals, most CD patients are aware of foods that provide adverse or beneficial effects. This study seeks to categorise foods in relation to their effects on symptoms of CD, in a New Zealand Caucasian population. Four hundred and forty-six subjects from two different centres in New Zealand were recruited into the study. An extensive dietary questionnaire (257 food items in 15 groups) recorded self-reported dietary tolerances and intolerances. Across each of the food groups, there were statistically significant differences among responses to foods. A two-dimensional graphical summary enabled stratification of foods according to the probability that they will be either beneficial or detrimental. A small number of foods are frequently considered to be beneficial, including white fish, salmon and tuna, gluten-free products, oatmeal, bananas, boiled potatoes, sweet potatoes (kumara), pumpkin, soya milk, goat's milk and yoghurt. Foods that are typically considered detrimental include grapefruit, chilli or chilli sauce, corn and corn products, peanuts, cream, salami, curried foods, cola drinks, high energy drinks, beer, and red wine. For a number of the food items, the same item that was beneficial for one group of subjects was detrimental to others; in particular soya milk, goat's milk, yoghurt, oatmeal, kiwifruit, prunes, apple, broccoli, cauliflower, linseed, pumpkin seed, sunflower seed, ginger and ginger products, beef, lamb, liver, and oily fish. It was not possible to identify a specific group of food items that should be avoided by all CD patients. The wide range of detrimental items suggests that dietary maintenance of remission is likely to be difficult, and to exclude a substantial number of foods. Personalised diets may be especially important to these individuals.

Thermodynamics of binding of regulatory ligands to tissue transglutaminase

The transamidating activity of tissue transglutaminase is regulated by the ligands calcium and GTP, via conformational changes which facilitate or interfere with interaction with the peptidyl-glutamine substrate. We have analysed binding of these ligands by calorimetric and computational approaches. In the case of GTP we have detected a single high affinity site (K (D) approximately 1 microM), with moderate thermal effects suggestive that binding GTP involves replacement of GDP, normally bound to the protein. On line with this possibility no significant binding was observed during titration with GDP and computational studies support this view. Titration with calcium at a high cation molar excess yielded a complex binding isotherm with a number of "apparent binding sites" in large excess over those detectable by equilibrium dialysis (6 sites). This binding pattern is ascribed to occurrence of additional thermal contributions, beyond those of binding, due to the occurrence of conformational changes and to catalysis itself (with protein self-crosslinking). In contrast only one site for binding calcium with high affinity (K (D) approximately 0.15 microM) is observed with samples of enzyme inactivated by alkylation at the active site (to prevent enzyme crosslinkage and thermal effects of catalysis). These results indicate an intrinsic ability of tissue transglutaminase to bind calcium with high affinity and the necessity of careful reassessment of the enzyme regulatory pattern in relation to the concentrations of ligands in living cells, taking also in account effects of ligands on protein subcellular compartimentation.

Stratifying risk for celiac disease in a large at-risk United States population by using HLA alleles

BACKGROUND & AIMS

Susceptibility to celiac disease (CD) is related to HLA-DQ2 and DQ8 alleles and the heterodimers they encode. The objective of this study was to stratify risk for CD on the basis of HLA-DQ genotype.

METHODS

DNA from 10,191 subjects who are at risk for CD was analyzed for HLA-DQ haplotypes. Individuals with CD were identified as those who tested positive for anti-endomysial immunoglobulin A (EMA+) in an immunofluorescence assay.

RESULTS

Samples homozygous for DQ2.5 (HLA-DQA1 05-DQB1 02) or DQ2.2/DQ2.5 (HLA-DQA1 05-DQB1 02 and HLA-DQA1 0201-DQB1 02) comprised 5.38% of the total; 28.28% of these were EMA+ (95% confidence interval [CI], 24.55-32.26). Of the samples that were DQ2.5 heterozygous (HLA-DQA1 05-DQB1 02); 9.09% were EMA+ (95% CI, 7.82-10.51). Among samples in which HLA-DQ8 (HLA-DQA1 03-DQB1 0302) was detected, 8.42% of homozygotes (95% CI, 3.71-15.92) and 2.11% of heterozygotes (95% CI, 1.43-3.00) were EMA+. Samples with DQ2.2/DQ8 or DQ2.5/DQ8 comprised 5.08% of the total, and 11.78% of these were EMA+ (95% CI, 9.13-14.87). HLA-DQ2 and HLA-DQ8 were absent in 4283 samples (42.03% of the total); 0.16% of these samples were EMA+ (95% CI, 0.07-0.34).

CONCLUSIONS

High-resolution, sequence-specific oligonucleotide probe typing with 35 DQA1-specific and 37 DQB1-specific probes of DNA from more than 10,000 subjects was used to stratify risk of CD in an at-risk U.S. population. DQ2 homozygosity (DQ2.5/DQ2.2+2.5) increased risk for CD, estimated by the rate of EMA positivity, compared with the entire sample population and other DQ genotypes. These data suggest a quantitative relationship between the type/proportion of DQ heterodimers and the risk of CD and identify potential immunotherapeutic targets.

Recent advances in refractory coeliac disease: a review

Coeliac disease (CD) is an immune-mediated disease of the small intestine caused by intolerance to gluten. Removal of gluten from the diet results in a return to normal health for the majority of patients. A significant proportion of patients do not respond to a gluten-free diet and are considered to be suffering from refractory coeliac disease (RCD). Two types of RCD are now recognized: type 1 RCD is characterized by a polyclonal population of intraepithelial lymphocytes (IELs) with a normal immunophenotype, and type 2 RCD shows monoclonal IELs with an aberrant immunoprofile. Patients with RCD have a high risk of complications such as ulcerative jejunitis (UJ) and enteropathy-type T-cell lymphoma (ETTL). RCD2 may represent an early stage in the development of overt lymphoma. The diagnosis of RCD, therefore, has important implications, but remains a challenging area. In this paper we review the latest developments in RCD, including the diagnostic approach and a discussion of the key clinical, histological, immunohistochemical and molecular features of RCD and its complications.

Increased FOXP3 expression in small-bowel mucosa of children with coeliac disease and type I diabetes mellitus

OBJECTIVE

To determine whether the expression of FOXP3 is changed in small-bowel mucosa in coeliac disease (CD).

MATERIAL AND METHODS

The study comprised 52 patients (mean age 8.01+/-6.14 years) who had undergone small-bowel biopsies. CD only was diagnosed in 16 patients, and CD with type I diabetes mellitus (T1D) in 7. These 23 patients and 4 others without CD had partial or subtotal villous atrophy (PVA, SVA). Twenty-five persons without CD had normal mucosa. The transcription level of the FOXP3 gene (Hs00203958_m1) was evaluated in biopsy samples (small bowel) using TaqMan gene expression assays. FOXP3 protein in mucosal cells was evaluated with mouse anti-human FOXP3 antibodies and CD25(+), and CD4(+) T cells were evaluated by mouse monoclonal antibodies.

RESULTS

Expression of FOXP3 mRNA was higher in both PVA and SVA compared to normal mucosa (p=0.007). Patients with CD and T1D had higher expression of FOXP3 mRNA than patients with CD alone (p=0.02). The number of FOXP3(+) cells in intestinal mucosa was higher in patients with CD, especially those with coexisting T1D, than in those with normal mucosa (p=0.01). The results of double staining showed that, among all positive cells, FOXP3 expression alone was revealed in 25.6% of the cells, CD25 positivity in 18% and both markers simultaneously were found in 56.5% of lymphocytes (p=0.03). Double staining for CD4 and FOXP3 showed that 87.5% of cells were CD4(+), 2.8% were FOXP3(+) and 9.7% of cells simultaneously expressed the CD4 and FOXP3 markers.

CONCLUSIONS

A more pronounced expression of FOXP3 mRNA and also the number of FOXP3(+) cells (with simultaneous expression of CD25 and CD4 markers) were found in the small-bowel biopsy specimens obtained from children with CD, particularly those with coexisting T1D, compared with the FOXP3 expression in normal mucosa.

Isolation and culture of fibroblasts from endoscopic duodenal biopsies of celiac patients

BACKGROUND

Fibroblasts are actually considered pivotal in inflammation and tissue remodelling process and for these reasons they are involved in the pathogenesis of autoimmune disorders such as celiac disease. Investigations to define the role of fibroblasts in celiac diseases are obstructed by the absence of specific models. Our objective is to isolate and culture primary fibroblasts from endoscopic duodenal biopsies of celiac and non-celiac subjects, to analyze their growth patterns and the morphometric characteristics.

METHODS

60 duodenal bioptic specimens from 20 celiac patients and 114 from 38 non-celiac subjects were mechanically chopped and enzymatically digested in order to obtain primary cell cultures. Growth patterns, karyotype (Q-banding analysis), expression of typing proteins (fibroblast surface protein and cytokeratin 20) and morphometric parameters (diameters and their ratio, perimeter, area and perimeter/area ratio at computerised image analysis) were investigated on cultured cells.

RESULTS

Primary cells were successfully cultured in 78% of the collected duodenal biopsies. Cultured cells, expressing the fibroblast surface protein, were negative for cytokeratine 20 and maintained a normal kariotype. Cells grew slowly without differences between the celiac and the non celiac group. Morphometric analysis of celiac fibroblasts revealed significantly increased dimensions, with a preserved diameters ratio, and a reduced perimeter/area ratio.

CONCLUSION

For the first time this study demonstrates the feasibility of culturing primary fibroblast cell from endoscopic duodenal biopsies in celiac and non-celiac subjects, opening a new window of opportunity in studies intended to establish the role of fibroblasts as a possible partaker in the pathogenesis of the celiac mucosal damage.

Phenotypic variance in childhood coeliac disease and the HLA-DQ/DR dose effect

OBJECTIVE

Coeliac disease (CD) is associated with HLA-DQ2 and DQ8. The clinical picture is variable and certain human leucocyte antigen (HLA) DQ/DR combinations have a higher relative risk (RR) for CD than others. Moreover, the HLA-DQ gene-dose effect has an impact on the strength of the gluten-specific T-cell response and thus may correlate with clinical presentation and severity of CD. The aim of this study was to determine the correlation between HLA-DQ/DR-based genotypes and the variation in phenotypes of the disease.

MATERIAL AND METHODS

A total of 113 non-related Caucasian children clinically diagnosed with CD during the period 1980-2003 with a known HLA type were included in the study. Patients were divided into four categories according to amount of disease expression predisposing to HLA-DQ2 or HLA-DQ8 molecules and the known RR of their HLA-DR/DQ type for CD: high (DR3DQ2 homozygous and DR3DQ2/DR7DQ2), substantial (DR3DQ2/DR5DQ7 and DR5DQ7/DR7DQ2), moderate (DR3DQ2-DR4DQ8 and DR3DQ2/DR*DQ*) and low (DR7DQ2/DR*DQ*, DR4DQ8- DR*DQ* and DR*DQ*- DR*DQ*). The clinical data and HLA genotypes of these patients were compared.

RESULTS

The 113 children were diagnosed with CD at a mean age of 4.6 years and boys were significantly older than girls when diagnosed (p=0.01). RR for having CD was highest for the high HLA-risk group (RR 8.1). With the exception of a greater frequency of abdominal distension and fewer non-gastrointestinal symptoms in the substantial HLA-risk group, there were no significant differences in clinical characteristics or degree of severity of the small-bowel histological findings between the children in the different HLA-risk groups.

CONCLUSION

No correlation was found between disease severity and a double HLA-DQ2 gene dose.

Regional variation in celiac disease risk within Sweden revealed by the nationwide prospective incidence register

AIM

To determine if there is any regional celiac disease (CD) risk variation in the Swedish childhood population.

METHODS

Prospective nationwide Swedish incidence register of CD in children 0-15 years of age, with the present analysis covering the period from 1998 to 2003. ESPGHAN diagnostic criteria for CD were used. Regions were classified according to the Nomenclature of Territorial Units for Statistics. The incidence rate for each region, gender, age group and year of diagnosis was calculated.

RESULTS

A regional variation in CD risk was demonstrated. The childhood populations in 'West Sweden' and 'Småland and the islands', situated in the southern part of the country, had a significantly higher incidence rate compared to in 'North Middle Sweden' and 'Stockholm', situated in the central part. This regional variation was not explained by variations in risk by gender, age at diagnosis or year of diagnosis.

CONCLUSION

The Swedish regional variation in CD risk supports multifactorial disease aetiology. Continued efforts are warranted to define factors, besides gluten exposure, that modulate CD risk.

Tetraploid and hexaploid wheat varieties reveal large differences in expression of alpha-gliadins from homoeologous Gli-2 loci

BACKGROUND

Alpha-gliadins form a multigene protein family encoded by multiple alpha-gliadin (Gli-2) genes at three genomic loci, Gli-A2, Gli-B2 and Gli-D2, respectively located on the homoeologous wheat chromosomes 6AS, 6BS, and 6DS. These proteins contain a number of important celiac disease (CD)-immunogenic domains. The alpha-gliadins expressed from the Gli-B2 locus harbour fewer conserved CD-epitopes than those from Gli-A2, whereas the Gli-D2 gliadins have the highest CD-immunogenic potential. In order to detect differences in the highly CD-immunogenic alpha-gliadin fraction we determined the relative expression level from the homoeologous Gli-2 loci in various tetraploid and hexaploid wheat genotypes by using a quantitative pyrosequencing method and by analyzing expressed sequence tag (EST) sequences.

RESULTS

We detected large differences in relative expression levels of alpha-gliadin genes from the three homoeologous loci among wheat genotypes, both as relative numbers of expressed sequence tag (EST) sequences from specific varieties and when using a quantitative pyrosequencing assay specific for Gli-A2 genes. The relative Gli-A2 expression level in a tetraploid durum wheat cultivar ('Probstdorfer Pandur') was 41%. In genotypes derived from landraces, the Gli-A2 frequency varied between 12% and 58%. In some advanced hexaploid bread wheat cultivars the genes from locus Gli-B2 were hardly expressed (e.g., less than 5% in 'Lavett') but in others they made up more than 40% (e.g., in 'Baldus').

CONCLUSION

Here, we have shown that large differences exist in relative expression levels of alpha-gliadins from the homoeologous Gli-2 loci among wheat genotypes. Since the homoelogous genes differ in the amount of conserved CD-epitopes, screening for differential expression from the homoeologous Gli-2 loci can be employed for the pre-selection of wheat varieties in the search for varieties with very low CD-immunogenic potential. Pyrosequencing is a method that can be employed for such a 'gene family-specific quantitative transcriptome profiling'.

Autoimmune disorders in patients affected by celiac sprue and inflammatory bowel disease

BACKGROUND

Although clinically different, celiac sprue and inflammatory bowel disease are characterized by chronic intestinal inflammation and associated extraintestinal manifestations.

AIMS

To assess and compare the presence of autoimmune disorders in patients affected by celiac sprue and inflammatory bowel disease referred to a single tertiary centre.

METHODS

From October 2005 to January 2006, a total of 297 consecutive outpatients were enrolled in this cross-sectional study. Diagnoses of celiac sprue and inflammatory bowel disease were based on standard criteria. Data were recorded using an operator-assisted questionnaire: 18 autoimmune diseases, when adequately confirmed, were considered.

RESULTS

Clinical characteristics of our patients are in conformity with those of the literature. The prevalence of associated autoimmune diseases was 25.6%, 21.1%, and 10% in patients affected by celiac sprue, Crohn's disease, and ulcerative colitis. Between the prevalence in celiac sprue and Crohn's disease there was no difference, whereas a significant difference was present between these two diseases and ulcerative colitis. The most frequent disorder in all three groups was Hashimoto's thyroiditis.

CONCLUSIONS

Celiac sprue and Crohn's disease show similar prevalence of associated autoimmune disease, higher than the prevalence in ulcerative colitis. The two diseases share the same pathogenic immunologic response and altered intestinal permeability.

The presence of small intestinal intraepithelial gamma/delta T-lymphocytes is inversely correlated with lymphoma development in refractory celiac disease

BACKGROUND

In refractory celiac disease (RCD) type II, a phenotypically aberrant (CD7+ CD3- CD4/8-cytoplasmicCD3+) intraepithelial lymphocyte (IEL) population is present, and 50-60% of these patients develop enteropathy-associated T-cell lymphoma (EATL). TCRgammadelta+ IELs play an important role in mucosal repair, homeostasis, and tumor surveillance. Recently, human small intestinal TCRgammadelta+ IELs were shown to have regulatory potential in uncomplicated celiac disease (CD).

AIM

In the present study, we investigated whether TCRgammadelta+ IELs are decreased in RCD II, providing a possible explanation for persisting mucosal damage and inflammation, and the emergence of aberrant T cells with clonal expansion to EATL.

DESIGN AND METHODS

Multiparameter flow cytometric immunophenotyping was performed on IELs isolated from fresh small bowel biopsy specimens of relatively large distinct CD patient and control groups (N = 87).

RESULTS

A significantly lower percentage of TCRgammadelta+ IELs was found in RCD II as compared to all other CD groups. In contrast, in uncomplicated CD patients significantly more TCRgammadelta+ IELs were found than in controls. Overall, there is a clear negative relation between TCRgammadelta+ IELs and aberrant IELs. Interestingly, TCRgammadelta+ IELs increase again in RCD II after effective therapy.

CONCLUSIONS

The observed negative relation between TCRgammadelta+ and aberrant IELs, along with their known regulatory capacity in uncomplicated CD, implies that TCRgammadelta+ IELs may play a crucial role in mucosal repair, regaining homeostasis and possibly even tumor surveillance. These cells may be important markers, in addition to the aberrant T cells, to differentiate between disease categories and to evaluate the effectiveness of therapeutic strategies.

Difference in celiac disease risk between Swedish birth cohorts suggests an opportunity for primary prevention

OBJECTIVES

Sweden experienced a unique epidemic of celiac disease in children <2 years of age. The epidemic was partly explained by changes in infant feeding over time and indicated a multifactorial pathogenesis. The main aim of this study was to analyze celiac disease risk in epidemic and postepidemic birth cohorts up to preschool age, to explore further the opportunity for primary prevention.

METHODS

A population-based incidence register of celiac disease in children covering the entire nation from 1998 to 2003 and part of the country back to 1973 was analyzed. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition diagnostic criteria for celiac disease were used. The annual incidence rate for each age group and the cumulative incidence according to age for each birth cohort were calculated.

RESULTS

A considerable difference in cumulative incidences of celiac disease at comparable ages was demonstrated between birth cohorts from the epidemic and postepidemic periods. The difference persisted during the preschool years, although it decreased somewhat with age. During the last years of the follow-up period, there was again a successive increase in incidence rate among children <2 years of age.

CONCLUSIONS

The difference in celiac disease risk between birth cohorts at comparable ages suggests an opportunity for primary prevention. This highlights the importance of further exploring the role of infant feeding and exogenous factors besides dietary gluten that might initiate or prevent disease development. Moreover, on the basis of postepidemic incidence trends, we speculate that the Swedish epidemic might not have been as unique as thought previously, although its magnitude was striking.

Detailed analysis of the expression of an alpha-gliadin promoter and the deposition of alpha-gliadin protein during wheat grain development

BACKGROUND AND AIMS

Alpha-gliadin proteins are important for the industrial quality of bread wheat flour, but they also contain many epitopes that can trigger celiac (coeliac) disease (CD). The B-genome-encoded alpha-gliadin genes, however, contain very few epitopes. Controlling alpha-gliadin gene expression in wheat requires knowledge on the processes of expression and deposition of alpha-gliadin protein during wheat grain development.

METHODS

A 592-bp fragment of the promotor of a B-genome-encoded alpha-gliadin gene driving the expression of a GUS reporter gene was transformed into wheat. A large number of transgenic lines were used for data collection. GUS staining was used to determine GUS expression during wheat kernel development, and immunogold labelling and tissue printing followed by staining with an alpha-gliadin-specific antibody was used to detect alpha-gliadin protein deposited in developing wheat kernels. The promoter sequence was screened for regulatory motifs and compared to other available alpha-gliadin promoter sequences.

KEY RESULTS

GUS expression was detected primarily in the cells of the starchy endosperm, notably in the subaleurone layer but also in the aleurone layer. The alpha-gliadin promoter was active from 11 days after anthesis (DAA) until maturity, with an expression similar to that of a 326-bp low molecular weight (LMW) subunit gene promoter reported previously. An alpha-gliadin-specific antibody detected alpha-gliadin protein in protein bodies in the starchy endosperm and in the subaleurone layer but, in contrast to the promoter activity, no alpha-gliadin was detected in the aleurone cell layer. Sequence comparison showed differences in regulatory elements between the promoters of alpha-gliadin genes originating from different genomes (A and B) of bread wheat both in the region used here and upstream.

CONCLUSIONS

The results suggest that additional regulator elements upstream of the promoter region used may specifically repress expression in the aleurone cell layer. Observed differences in expression regulator motifs between the alpha-gliadin genes on the different genomes (A and B) of bread wheat leads to a better understanding how alpha-gliadin expression can be controlled.

Infiltration of forkhead box P3-expressing cells in small intestinal mucosa in coeliac disease but not in type 1 diabetes

Because the role of regulatory T cells in the intestinal inflammation is unknown in coeliac disease (CD) and type 1 diabetes (T1D), the expression of forkhead box P3 (FoxP3), CD25, transforming growth factor-beta, interferon (IFN)-gamma, interleukin (IL)-4, IL-8, IL-10, IL-15 and IL-18 was measured by quantitative reverse transcription-polymerase chain reaction in the small intestinal biopsies from paediatric patients with active or potential CD, T1D and control patients. The numbers of FoxP3- and CD25-expressing cells were studied with immunohistochemistry. Enhanced intestinal expressions of FoxP3, IL-10 and IFN-gamma mRNAs were found in active CD when compared with controls (P-values < 0.001, 0.004, <0.001). In potential CD, only the expression of IFN-gamma mRNA was increased. The numbers of FoxP3-expressing cells were higher in active and potential CD (P < 0.001, P = 0.05), and the ratio of FoxP3 mRNA to the number of FoxP3-positive cells was decreased in potential CD when compared with controls (P = 0.007). The ratio of IFN-gamma to FoxP3-specific mRNA was increased in active and potential CD (P = 0.001 and P = 0.002). Patients with T1D had no changes in regulatory T cell markers, but showed increased expression of IL-18 mRNA. The impaired up-regulation of FoxP3 transcripts despite the infiltration of FoxP3-positive cells in potential CD may contribute to the persistence of inflammation. The increased ratio of IFN-gamma to FoxP3 mRNA in active and potential CD suggests an imbalance between regulatory and effector mechanisms. The increased intestinal expression of IL-18 mRNA in patients with T1D adds evidence in favour of the hypothesis that T1D is associated with derangements in the gut immune system.

Imbalance in the composition of the duodenal microbiota of children with coeliac disease

Coeliac disease (CD) is the most common immune-mediated enteropathy characterized by chronic inflammation of the small intestinal mucosa. The ingestion of gluten is responsible for the symptoms of CD, but other environmental factors are also thought to play a role in this disorder. In this study, the composition of the duodenal microbiota of coeliac children with active disease, symptom-free CD patients on a gluten-free diet and control children was determined. Bacteriological analyses of duodenal biopsy specimens were carried out by fluorescent in situ hybridization coupled with flow cytometry. The proportions of total bacteria and Gram-negative bacteria were significantly higher in CD patients with active disease than in symptom-free CD patients and controls. Bacteroides and Escherichia coli groups were significantly more abundant in CD patients with active disease than in controls, whilst these bacterial deviations were normalized in symptom-free CD patients. The ratio of Lactobacillus--Bifidobacterium to Bacteroides--E. coli was significantly reduced in coeliac patients with either active or inactive disease compared with controls. The differences in Atopobium, Eubacterium rectale--Clostridium coccoides, Clostridium histolyticum, Clostridium lituseburense, sulphate-reducing bacteria and Faecalibacterium prausnitzii populations among the three groups of children were less relevant. Overall, the higher incidence of Gram-negative and potentially pro-inflammatory bacteria in the duodenal microbiota of coeliac children was linked to the symptomatic presentation of the disease and could favour the pathological process of the disorder.

Coeliac disease-specific autoantibodies targeted against transglutaminase 2 disturb angiogenesis

Coeliac disease is characterized by immunoglobulin-A (IgA)-class autoantibodies targeted against transglutaminase 2 (TG2), a multi-functional protein also with a role in angiogenesis. These antibodies are present in patient serum but are also found bound to TG2 below the epithelial basement membrane and around capillaries in the small intestinal mucosa. Based on these facts and the information that the mucosal vasculature of coeliac patients on a gluten-containing diet is disorganized, we studied whether the coeliac disease-specific autoantibodies targeted against TG2 would disturb angiogenesis. The effects of coeliac disease-specific autoantibodies on in vitro angiogenesis were studied in angiogenic cell cultures. The binding of the antibodies to cells, endothelial sprouting, migration of both endothelial and vascular mesenchymal cells, the integrity of the actin cytoskeleton in both cell types and the differentiation of vascular mesenchymal cells were recorded. In vitro, IgA derived from coeliac disease patients on a gluten-containing diet binds to surface TG2 on endothelial and vascular mesenchymal cells and this binding can be inhibited by the removal of TG2. In addition, coeliac disease-specific autoantibodies targeting TG2 disturb several steps of angiogenesis: endothelial sprouting and the migration of both endothelial and vascular mesenchymal cells. Furthermore, the autoantibodies cause disorganization of the actin cytoskeleton in both capillary cell types that account most probably for the defective cellular migration. We conclude that coeliac disease-specific autoantibodies recognizing TG2 inhibit angiogenesis in vitro. This disturbance of the angiogenic process could lead in vivo to the disruption of the mucosal vasculature seen in coeliac disease patients on a gluten-containing diet.