Secretion of celiac disease autoantibodies after in vitro gliadin challenge is dependent on small-bowel mucosal transglutaminase 2-specific IgA deposits

Background: In celiac disease gluten, the disease-inducing toxic component in wheat, induces the secretion of autoantibodies which are targeted against transglutaminase 2 (TG2). These autoantibodies are produced in the small-intestinal mucosa, where they can be found deposited extracellularly below the epithelial basement membrane and around mucosal blood vessels. In addition, during gluten consumption these autoantibodies can also be detected in patients' serum but disappear from the circulation on a gluten-free diet. Interestingly, after adoption of a gluten-free diet the serum autoantibodies disappear from the circulation more rapidly than the small-intestinal mucosal autoantibody deposits. The toxicity of gluten and the secretion of the disease-specific autoantibodies have been widely studied in organ culture of small-intestinal biopsy samples, but results hitherto have been contradictory. Since the mucosal autoantibodies disappear slowly after a gluten-free diet, our aim was to establish whether autoantibody secretion to organ culture supernatants in treated celiac disease patient biopsies is related to the duration of the diet and further to the preexistence of mucosal TG2-specific IgA deposits in the cultured biopsy samples. Results: In the organ culture system conducted with biopsies derived from treated celiac disease patients, gliadin induced secretion of autoantibodies to culture supernatants, reduced epithelial cell height and increased the density of lamina proprial CD25+ cells. However, these changes could be demonstrated only in biopsies from short-term treated celiac disease patients, where the small-intestinal mucosal TG2-specific IgA autoantibody deposits were still present. Furthermore, in these biopsies autoantibody secretion could be stimulated fully only after a 48-hour gliadin challenge. Conclusion: Our results show that studies focusing on the toxic effects of gliadin in the organ culture system should be carried out with biopsy samples from short-term treated celiac disease patients who are likely still to have mucosal IgA deposits present. In addition to providing an explanation for the discrepancies in previous publications, the present study also enables further validation of the organ culture method

The impact of human breast milk components on the infant metabolism

Background & aims Breastfeeding is beneficial for mothers and infants. Underlying mechanisms and biochemical mediators thus need to be investigated to develop and support improved infant nutrition practices promoting the child health. We analysed the relation between maternal breast milk composition and infant metabolism. Methods 196 pairs of mothers and infants from a European research project (PreventCD) were studied. Maternal milk samples collected at month 1 and month 4 after birth were analysed for macronutrient classes, hormone, and fatty acid (FA) content. Phospholipids, acylcarnitines, and amino acids were measured in serum samples of 4-month old infants. Associations between milk components and infant metabolites were analysed with spearman correlation and linear mixed effect models (LME). P-values were corrected for multiple testing (P-LME). Results Month 1 milk protein content was strongly associated with infant serum lyso-phosphatidylcholine (LPC) 14: 0 (P-LME = 0.009). Month 1 milk insulin was associated to infant acetylcarnitine (P-LME = 0.01). There were no associations between milk protein content and serum amino acids and milk total fat content and serum polar lipids. Middle- and odd-chain FA% in breast milk at both ages were significantly related to serum LPC and sphingomyelins (SM) species in infant serum (all P-LME < 0.05), while FA% 20: 5n(-3) and 22: 6n(-3) percentages were significantly associated to serum LPC 22:6 (P-LME = 1.91x10(-4)/7.93x10(-5)) in milk only at month 4. Other polyunsaturated fatty acids and hormones in milk showed only weak associations with infant serum metabolites. Conclusions Infant serum LPC are influenced by breast milk FA composition and, intriguingly, milk protein content in early but not late lactation. LPC 14:0, previously found positively associated with obesity risk, was the serum metabolite which was the most strongly associated to milk protein content. Thus, LPC 14:0 might be a key metabolite not only reflecting milk protein intake in infants, but also relating high protein content in milk or infant formula to childhood obesity risk

Thioredoxin is involved in endothelial cell extracellular transglutaminase 2 activation mediated by celiac disease patient IgA

Purpose: To investigate the role of thioredoxin (TRX), a novel regulator of extracellular transglutaminase 2 (TG2), in celiac patients IgA (CD IgA) mediated TG2 enzymatic activation. Methods: TG2 enzymatic activity was evaluated in endothelial cells (HUVECs) under different experimental conditions by ELISA and Western blotting. Extracellular TG2 expression was studied by ELISA and immunofluorescence. TRX was analysed by Western blotting and ELISA. Serum immunoglobulins class A from healthy subjects (H IgA) were used as controls. Extracellular TG2 enzymatic activity was inhibited by R281. PX12, a TRX inhibitor, was also employed in the present study. Results: We have found that in HUVECs CD IgA is able to induce the activation of extracellular TG2 in a dose-dependent manner. Particularly, we noted that the extracellular modulation of TG2 activity mediated by CD IgA occurred only under reducing conditions, also needed to maintain antibody binding. Furthermore, CD IgA-treated HUVECs were characterized by a slightly augmented TG2 surface expression which was independent from extracellular TG2 activation. We also observed that HUVECs cultured in the presence of CD IgA evinced decreased TRX surface expression, coupled with increased secretion of the protein into the culture medium. Intriguingly, inhibition of TRX after CD IgA treatment was able to overcome most of the CD IgA-mediated effects including the TG2 extracellular transamidase activity. Conclusions: Altogether our findings suggest that in endothelial cells CD IgA mediate the constitutive activation of extracellular TG2 by a mechanism involving the redox sensor protein TRX

Systematic review: early feeding practices and the risk of coeliac disease. A 2022 update and revision

Background: The effects of early feeding practices on the risk of coeliac disease (CD) remain debated. Aims: To update evidence on these practices on the risk of CD and/or CD-related autoimmunity (CDA), defined as anti-transglutaminase or anti-endomysial antibody positivity. Methods: We searched MEDLINE, EMBASE and the Cochrane Library to May 2022 for randomised controlled trials (RCTs) and observational studies. Results: We included 36 publications (30 studies). In the population at genetic risk of developing CD (HLA DQ2/DQ8-positive), exclusive or any breastfeeding and longer breastfeeding duration did not reduce the risk of developing CD/CDA during childhood. While a meta-analysis of four case–control studies showed a decreased risk for CD when gluten was introduced during breastfeeding, this was not shown in RCTs and cohort studies. Age at gluten introduction was not associated with cumulative CD/CDA risk, although two RCTs suggested that earlier gluten introduction was associated with earlier CDA appearance. Evidence from six observational studies suggests that consumption of a higher amount of gluten at weaning and/or thereafter may increase CD risk. There is insufficient evidence to determine the amount of gluten associated with an increased CD/CDA risk. Regarding whether infant feeding practices modulate the risk conferred by different HLA genotypes results were inconsistent. Conclusions: For the population at genetic risk of CD, breastfeeding and age at gluten introduction have no effect on its cumulative incidence during childhood. There is some evidence for an effect of the amount of gluten consumed at weaning and/or thereafter on CD/CDA risk

Outcome measures in coeliac disease trials: the Tampere recommendations

A gluten-free diet is the only treatment option of coeliac disease, but recently an increasing number of trials have begun to explore alternative treatment strategies. We aimed to review the literature on coeliac disease therapeutic trials and issue recommendations for outcome measures

Celiac Disease: Past, Present, and Future Challenges Dedicated to the Memory of Our Friend and Colleague, Prof David Branski (1944-2013)

Transplantation and autoimmunit

Secretion of celiac disease autoantibodies after in vitro gliadin challenge is dependent on small-bowel mucosal transglutaminase 2-specific IgA deposits-2

D either with medium only or with PT-gliadin for 24 hours. The median values (horizontal line) and P values are calculated for each group showing a statistically significant increase in CD25+ cells only in those treated celiac disease cases who had small-bowel mucosal IgA deposits in the cultured biopsy samples.<p><b>Copyright information:</b></p><p>Taken from "Secretion of celiac disease autoantibodies after in vitro gliadin challenge is dependent on small-bowel mucosal transglutaminase 2-specific IgA deposits"</p><p>http://www.biomedcentral.com/1471-2172/9/6</p><p>BMC Immunology 2008;9():6-6.</p><p>Published online 29 Feb 2008</p><p>PMCID:PMC2275217.</p><p></p