Celiac disease: clinical update

The Gluten-Free Diet for Celiac Disease: Critical Insights to Better Understand Clinical Outcomes

The gluten-free diet (GFD) remains a complex paradigm in managing celiac disease (CeD) in children and adults, and there are many reasons why GFD adherence should be strict to improve outcomes. However, this is a challenging task for patients, since they need to have access to quality healthcare resources that facilitate optimal GFD adherence. Understanding the strengths and weaknesses of the GFD, tackling coexisting nutritional deficiencies, and dealing with complex situations, such as seronegative CeD or non-responsive CeD, all require the involvement of a multidisciplinary team. The short- and long-term follow-up of CeD patients should preferably be performed by a combined Gastroenterology and Nutrition service with well-defined quality standards and the multidisciplinary involvement of physicians, nurses, dietitians, and psychologists. Nutritional advice and counseling by an experienced dietitian can reduce the costs associated with long-term follow-up of CeD patients. Likewise, psychological interventions may be essential in specific scenarios where implementing and sustaining a lifelong GFD can cause a significant psychological burden for patients. This manuscript aims to provide guidelines to improve clinical practice in the follow-up and monitoring of CeD patients and provide information on the nutritional risks of an ill-advised GFD. Clinicians, biochemists, food technologists, dietitians, and psychologists with a global view of the disease have been involved in its writing.

Inhibition of Transglutaminase 2 as a Therapeutic Strategy in Celiac Disease-In Vitro Studies in Intestinal Cells and Duodenal Biopsies

Enzymatic modification of gliadin peptides by human transglutaminase 2 (TG2) is a key mechanism in the pathogenesis of celiac disease (CD) and represents a potential therapeutic target. Recently, we have identified the small oxidative molecule PX-12 as an effective inhibitor of TG2 in vitro. In this study, we further investigated the effect of PX-12 and the established active-site directed inhibitor ERW1041 on TG2 activity and epithelial transport of gliadin peptides. We analyzed TG2 activity using immobilized TG2, Caco-2 cell lysates, confluent Caco-2 cell monolayers and duodenal biopsies from CD patients. TG2-mediated cross-linking of pepsin-/trypsin-digested gliadin (PTG) and 5BP (5-biotinamidopentylamine) was quantified by colorimetry, fluorometry and confocal microscopy. Cell viability was tested with a resazurin-based fluorometric assay. Epithelial transport of promofluor-conjugated gliadin peptides P31-43 and P56-88 was analyzed by fluorometry and confocal microscopy. PX-12 reduced TG2-mediated cross-linking of PTG and was significantly more effective than ERW1041 (10 µM, 15 ± 3 vs. 48 ± 8%, p < 0.001). In addition, PX-12 inhibited TG2 in cell lysates obtained from Caco-2 cells more than ERW1041 (10 µM; 12 ± 7% vs. 45 ± 19%, p < 0.05). Both substances inhibited TG2 comparably in the intestinal lamina propria of duodenal biopsies (100 µM, 25 ± 13% vs. 22 ± 11%). However, PX-12 did not inhibit TG2 in confluent Caco-2 cells, whereas ERW1041 showed a dose-dependent effect. Similarly, epithelial transport of P56-88 was inhibited by ERW1041, but not by PX-12. Cell viability was not negatively affected by either substance at concentrations up to 100 µM. PX-12 did not reduce TG2 activity or gliadin peptide transport in confluent Caco-2 cells. This could be caused by rapid inactivation or degradation of the substance in the Caco-2 cell culture. Still, our in vitro data underline the potential of the oxidative inhibition of TG2. The fact that the TG2-specific inhibitor ERW1041 reduced the epithelial uptake of P56-88 in Caco-2 cells further strengthens the therapeutic potential of TG2 inhibitors in CD.

Prevalence and clinical outcomes of COVID-19 in patients with pre-existing celiac disease: A systematic review and meta-analysis

There is a scarcity of scientific evidence addressing the outcomes of COVID-19 in celiac disease (CD) patients. This systematic review and meta-analysis aimed to evaluate the correlation between pre-existing CD and COVID-19. A rigorous literature search was conducted using multiple databases. All eligible observational studies were included from around the globe. The random effect model calculated the pooled prevalence and associated 95% confidence intervals (CI). Mantel-Haenszel odds ratios were produced to report the overall effect size using random effect models for severity and mortality outcomes. Funnel plots, Egger regression tests, and Begg-Mazumdar's rank correlation test were used to appraise publication bias. Data from 11 articles consisting of 44,378 CD patients were obtained. Overall pooled random-effects estimate of SARS-CoV-2 infection in CD patients was 4.25% (95% CI, I²  = 98%). Our findings also indicated that pre-existing CD was not associated with an increased risk of hospitalisation with COVID-19 illness (OR = 1.04, 95% CI 0.87-1.24, I²  = 0%) and mortality due to illness (OR = 0.92, 95% CI 0.56-1.5, I²  = 45%) compared with patients without pre-existing CD. No significant publication bias was evident in the meta-analysis. The preliminary data from our analysis suggest that SARS-CoV-2 infection in patients with pre-existing CD is not associated with an increased risk of hospitalisation or mortality. Additional studies are required to overcome the restrictions of the limited data available at present.

Restorative effects of Acetobacter ghanensis on the pathogenicity of gliadin-induced modulation of tight junction-associated gene expression in intestinal epithelial cells

Background/Aim: At present, a gluten-free diet is the only efficient way to treat celiac disease (CD). The development of novel approaches to lessen or counteract the pathogenic effects of gluten remains crucial for the treatment of CD. The aim in this investigation was to examine the restorative effects of Acetobacter ghanensis as a novel probiotic against gliadin-induced modulation in the barrier integrity of an intestinal epithelial cell (IEC) model (Caco-2). Methods: Fully differentiated Caco-2 cell monolayers were subjected to enzymatically digested gliadin with a pepsin and trypsin (PT) in the presence or absence of A. ghanensis for 90 min. The relative amounts of zonulin, zonula occludens-1 (ZO-1), claudin-1, and occludin mRNA expression were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Transepithelial electrical resistance (TEER) was evaluated to monitor the barrier integrity of cell monolayers. Statistical analyses were carried out using one- or two-way ANOVA followed by Tukey’s post-hoc analysis for multiple pairwise comparisons. Results: A significant upregulation (4.7-fold) of zonulin was noted in the PT-gliadin treated Caco-2 cells in comparison with the untreated controls (P<0.001). Conversely, gliadin-induced zonulin expression was markedly downregulated in the Caco-2 cells following exposure to A. ghanensis in the presence of PT-gliadin (P<0.001). Furthermore, prominent decreases in the mRNA expression levels of ZO-1 (45%) and occludin (40%) were seen in the PT-gliadin exposed Caco-2 cells compared to the untreated control cells (P<0.001). PT-gliadin in the Caco-2 cells did not significantly alter the mRNA levels of claudin-1 (P=0.172). Similarly to zonulin expression, the decreasing effect of PT-gliadin on ZO-1 was completely attenuated in the PT-gliadin-administrated Caco-2 cells following exposure to A. ghanensis (P<0.001). Conclusion: A. ghanensis restored the pathogenicity of PT-gliadin on intestinal barrier integrity.

Psychological Considerations for Food Intolerances: Celiac Sprue, Eosinophilic Esophagitis, and Non-Celiac Gluten Sensitivity

Several chronic digestive conditions are physiologically based on food intolerance, including celiac disease, nonceliac gluten sensitivity, and eosinophilic esophagitis. Patients are expected to follow medically prescribed diets to eliminate identified food triggers to control symptoms. However, the psychological impacts of these dietary approaches are largely unaddressed in clinical practice. Hypervigilance and anxiety regarding food and symptoms, and disordered eating, may emerge and negatively affect outcomes. Clinicians working with pediatric and adult populations with food intolerances should be aware of these psychological comorbidities, and equally emphasize effective ways to help patients manage the mental and physical aspects of their condition.

Food supplementation with wheat gluten leads to climbing performance decline in Drosophila melanogaster

Gluten sensitivity is associated with digestive and neurological disorders, correlating with abnormal amino acid levels, innate immune responses, gut dysbiosis and movement incoordination. However, the molecular mechanisms linking dietary gluten and brain function remain incompletely understood. We used Drosophila melanogaster to test the effects of gluten ingestion in locomotion performance. Whereas flies on control food showed decreased climbing performance after five weeks, flies exposed to food supplemented with different gluten concentrations showed a significant locomotion decline after three weeks of treatment. Future studies will determine the mechanisms underlying the observed gluten-dependent phenotypes to establish Drosophila models for gluten sensitivity.

An Effective Label-Free Electrochemical Aptasensor Based on Gold Nanoparticles for Gluten Detection

Nanomaterials can be used to modify electrodes and improve the conductivity and the performance of electrochemical sensors. Among various nanomaterials, gold-based nanostructures have been used as an anchoring platform for the functionalization of biosensor surfaces. One of the main advantages of using gold for the modification of electrodes is its great affinity for thiol-containing molecules, such as proteins, forming a strong Au-S bond. In this work, we present an impedimetric biosensor based on gold nanoparticles and a truncated aptamer for the quantification of gluten in hydrolyzed matrices such as beer and soy sauce. A good relationship between the R_ct values and PWG-Gliadin concentration was found in the range between 0.1–1 mg L⁻¹ of gliadin (corresponding to 0.2–2 mg L⁻¹ of gluten) with a limit of detection of 0.05 mg L⁻¹ of gliadin (corresponding to 0.1 mg L⁻¹ of gluten). The label-free assay was also successfully applied for the determination of real food samples.

Druggable monogenic immune defects hidden in diverse medical specialties: Focus on overlap syndromes

In the last two decades two new paradigms changed our way of perceiving primary immunodeficiencies: An increasing number of immune defects are more associated with inflammatory or autoimmune features rather than with infections. Some primary immune defects are due to hyperactive pathways that can be targeted by specific inhibitors, providing innovative precision treatments that can change the natural history of diseases. In this article we review some of these “druggable” inborn errors of immunity and describe how they can be suspected and diagnosed in diverse pediatric and adult medicine specialties. Since the availability of precision treatments can dramatically impact the course of these diseases, preventing the development of organ damage, it is crucial to widen the awareness of these conditions and to provide practical hints for a prompt detection and cure.