# Pro-Pre and Postbiotic in Celiac Disease
## 5 Probiotics  
### Bifidobacteria  
_Bifidobacteria_ are Gram-positive microorganisms with a high G + C DNA content. In 1899 they were isolated from the faeces of a breastfed infant. They are strictly anaerobic and occur in uniform Y- and V-shaped branched and bifurcated, spatulate or club-shaped forms; they are not motile and do not form spores. The branched appearance of _bifidobacteria_ depends not only on the strain but also on the medium used for cultivation. The genus _Bifidobacterium_ consists of 48 different taxa, of which 40 have been isolated in the gastrointestinal tract (GIT) of mammals, birds or insects, the remaining eight from sewage and fermented milk [26; 27; 28]. Acetic and lactic acids are produced by glucose fermentation in a ratio of 3:2 [27]. There are 32 species of _bifidobacteria_ (Table 1) identified by fermentation assays, observations of cell morphology, and electrophoretic mobility of enzymes such as transaldolase (14 types) or 6-phosphogluconate dehydrogenase (19 types; 32) [29]. [PERSON] and [PERSON]. (2010) demonstrated on CaCo-2 cells, the effects of _Bifidobacterium_ strains (_B. IATA-ES2, B. longum IATA-ES1_, and _B. animals IATA-A2_) by analyzing the peptide sequences produced by gastrointestinal digestion of gliadins and comparing toxic and proinflammatory effects. By RP-HPLC-ESI-MS/MS different patterns of gliadin peptides were detected in samples inoculated with _bifidobacteria_ compared to those not inoculated. Most of the peptides generated in the samples inoculated with _bifidobacteria_ showed lower molecular mass than those generated in the non-inoculated samples (2500 Da) during the in vitro digestion [30]. Gliadin peptides resulting from in vitro digestion, inoculated or not, with _B. animalis_ and _B. bifidum_ were cytotoxic to intestinal epithelial cells in vitro. Whereas, those inoculated with _B. longum_ were not. Furthermore, the analysis of pro-inflammatory cytokines showed that NF-kB, IL-1B TNF-a (\(p<0.05\)) were consistently reduced when digested gliadin was inoculated with all bifidobacterial strains compared with non-inoculated digested gliadin [30]. [PERSON] et al. (2012) demonstrated by MALDI-TOPF techniques that digested gliadin up-regulates proteins involved in actin rearrangement, inflammation and apoptosis in CaCo-2, while _B. longum_ CECT 7347 was able to reduce them (21 vs. 9). Many of these proteins were also involved in calcium homeostasis, cell survival and function [31]. \begin{table}
\begin{tabular}{l l l} \hline _B. adolescents_ * & _B. dentium_ * & _B. minimum_ \\ _B. angulatus_ * & _B. gallicum_ * & _B. pseudocatenulatum_ * \\ _B. animalis_ & _B.galliment_ * & _B. pseudolongumsubsp._ \\ _B. asteroids_ & _B. globosum_ & _Globosum_ \\ _B. bifidum_ & _B. indicium_ & _B. pseudolongumsubsp._ \\ _B. bourn_ & _B. infantis_ * & _Pseudolongum_ \\ _B. breve_ * & _B. inopinatum_ & _B. multimatum_ \\ _B. catenulatum_ * & _B. lactis_ & _B. sacculare_ \\ _B. cloerinum_ & _B. longum_ * & _B. subtile_ \\ _B. coryneforme_ & _B. magum_ & _B. suis_ \\ _B. cuniculi_ & _B. mercicum_ & _B. thermophilum_ \\ \hline \end{tabular}
\end{table} 
Table 1: _Bifidobacterium_ Species. [PERSON] et al. (2020) evaluated the effect of _Bifidobacterium_ species: _B. bifidum_, _B. longum_, _B.breve_, _B. animalis_ alone, and also a consortium of _Bifidobacterium_ on the digestion of intact gluten proteins (gliadins and glutenins) and the associated immunomodulatory responses elicited by the resulting peptides. The readout was activation of NF-kB p65 and expression of the cytokines TNF-\(\alpha\) and IL-1\(\beta\) in CaCo-2 cell cultures exposed to the peptides ([PERSON] et al. (2020)). [PERSON] et al. (2020) used a multi-strain probiotic preparation containing two strains of _lactobacillus_ (_L. paracasei_, _L. plantarum_) and three strains of _bifidobacteria_ (two different _B. breve and B. animalis_). They evaluated the ability of a probiotic mixture to hydrolyze gluten peptides after simulated gastrointestinal digestion of gliadin (PT-gliadin).