Prevenzione della celiachia: dieta con grano con ridotta quantità di epitopi stimolatori delle principali T-cellule.

by luciano

La ricerca scientifica ha più volte sostenuto ed incoraggiato l’utilizzazione di grani a bassa tossicità nella prevenzione della celiachia; Nella ricerca che ora presentiamo sono stati studiati alcuni grani evidenziando il loro profilo riguardo sia la presenza dei peptidi resistenti alla digestione gastro-intestinale sia, tra questi, quelli contenenti la frazione “tossica” (Summary of the GD-resistant peptides identified at the end of the duodenal phase and counting of the peptides encrypting full length epitopes relevant for celiac disease (CD) and wheat allergy  (table 3) “….omissis Even if none of them can be considered safe for CD patients, grain with reduced amount of major T-cell stimulatory epitopes may help in the prevention of CD, since previous studies demonstrated that the amount and duration to gluten exposure are strictly linked to the initiation of this pathology.” (A Comprehensive Peptidomic Approach to Characterize the Protein Profile of Selected Durum Wheat Genotypes: Implication for Coeliac Disease and Wheat Allergy. Rosa Pilolli , Agata Gadaleta, Luigia Di Stasio , Antonella Lamonaca, Elisabetta De Angelis , Domenica Nigro , Maria De Angelis , Gianfranco Mamone and Linda Monac. Published: 1 October 2019).

Abstract
The wheat varietal selection undertaken by breeders in recent decades has been tailored mainly to improve technological and productivity-related traits; however, the latter has resulted in a considerable impoverishment of the genetic diversity of wheat-based products available on the market. This pitfall has encouraged researchers to revalue the natural diversity of cultivated and non-cultivated wheat genotypes in light of their different toxic/immunogenic potential for celiac disease and wheat-allergic patients. In the present investigation, an advanced proteomic approach was designed for the global characterization of the protein profile of selected tetraploid wheat genotypes (Triticum turgidum). The approach combined proteins/peptides sequence information retrieved by specific enzymatic digestions (single and dual proteolytic enzymes) with protein digestibility information disclosed by means of in-vitro simulated human gastroduodenal digestion experiments. In both cases, the peptide pools were characterized by discovery analysis with liquid chromatography high-resolution tandem mass spectrometry, and specific amino acid sequences were identified via commercial software. The peptide list was screened for in silico toxicity/immunogenicity risk assessment, with the aid of various open-source bioinformatics tools for epitopes matching. Given the global information provided by the designed proteomic approach, the in silico risk assessment not only tackled toxicity implication for celiac disease patients, but also scouted for immunogenic sequences relevant for wheat allergic patients, achieving a comprehensive characterization of the protein profile of the selected genotypes. These latter were assessed to encrypt a variable number of toxic/immunogenic epitopes for celiac disease and wheat allergy, and as such they could represent convenient bases for breeding practices and for the development of new detoxification strategies.

Conclusion
In this investigation, we presented an in-depth analysis of the proteomic profile of selected durum wheat genotypes. An advanced proteomic approach based on high-resolution mass spectrometry was designed, which combined proteins/peptides sequence information retrieved by specific enzymatic digestions of Osborne protein fractions with protein digestibility information provided by in vitro simulated human gastroduodenal digestion experiments. This comprehensive approach not only made it possible to characterize the wheat genotypes and their genetic diversity, but also highlighted that the complexity of the model used to simulate in vitro the enzymatic digestion may influence the protein profile detected. The in silico evaluation of potential toxicity/immunogenicity for CD and WA patients proved that the selected genotypes encrypted a lower number of epitopes for both wheat related disorders, with particular attention towards the genotype number 5. Even if none of them can be considered safe for CD patients, grain with reduced amount of major T-cell stimulatory epitopes may help in the prevention of CD, since previous studies demonstrated that the amount and duration to gluten exposure are strictly linked to the initiation of this pathology [29,30]. As a future perspective of this work, the stability of protein expression and the consistency of the general trends observed here will be assessed with respect to different harvest years to confirm the relevance of the selected genotypes.

I risultati della ricerca saranno utili anche per il reintroduzione del glutine dopo un certo periodo in una dieta priva di glutine per i soggetti sensibili al glutine non celiaci, come suggerito in un’altra ricerca:“Once the diagnosis of NCGS is reasonably reached, the management and follow-up of patients is completely obscure. A logical approach is to undertake a gluten-free dietary regimen for a limited period (e.g., six months), followed by the gradual reintroduction of gluten. During the gluten-free diet, the ingestion of prolamine peptide (gliadin)-derived from wheat, rye, barley, oats, bulgur, and hybrids of these cereal grains-should be avoided. Rice, corn, and potatoes have been the typical substitutes, but nowadays other different cereals and pseudocereals, such as amaranth, buckwheat, manioc, fonio, teff, millet, quinoa, and sorghum, can be used. After some period on a gluten-free diet, the reintroduction of gluten can start with cereals of low gluten content (e.g., oats). In addition, einkorn farro (Triticummonococcum) can be used, having no direct in vitro or ex vivo toxicity and low (7%) gluten content[41]”. (Non-celiac gluten sensitivity: Time for sifting the grain. Luca Elli, Leda Roncoroni, and Maria Teresa Bardella. Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. ).

Approfondimento

A Comprehensive Peptidomic Approach to Characterize the Protein Profile of Selected Durum Wheat Genotypes: Implication for Coeliac Disease and Wheat Allergy.

La genetica della celiachia (Diffusione della celiachia nella popolazione)