Introduction: Numerous scientific studies have emphasized microbiome as a very important part of human health. Much has been learned about the diversity and distribution of human-associated microbiota, but still, little is known about its function during healthy and diseased states. It is a well-known fact that imbalance between useful and harmful bacteria is common in people who are suffering from food allergies. In recent years, probiotic supplements are used more often, not only to maintain the normal flora of the gastrointestinal system, but also to prevent and treat various gastrointestinal disorders. Gluten is a common food allergen. Incomplete digestion of its component gliadin in humans leads to formation of toxic peptides which can cause immune response. Studies have shown that administration of probiotic supplements provide a potential therapy for gluten-related diseases.
Materials and methods: Seven Lactobacillus strains (L. acidophilus 145, L. rhamnosus GG, L. plantarum IIA/5, L. casei VIIB/6, L. paracasei VIIB/5, L. paracasei ssp. paracasei and L. helveticus XA/2) were treated with gliadin solutions in vitro, to investigate gliadin effect on proliferation of these bacteria. Two parameters were evaluated - the growth rate and the lag phase duration. Strains were treated with gliadin dissolved in solution of 70% ethanol in 50 mM Tris/HCl or with gliadin dissolved in solution of 2% sodium chloride.
Results: Gliadin in EtOH/Tris solution induced proliferation of L. helveticus XA/2, L. plantarum II/5, L. rhamnosus GG and L. paracasei spp. paracasei 1753.
Gliadin dissolved in 2% sodium chloride stimulated proliferation of only L. helveticus XA/2 and L. plantarum II/5. In this experiment, the growth rate of these two strains was accelerating with increasing concentration of gliadin in solution of 2% NaCl, but the lag phase was prolonging, most presumably because the bacteria needed more time to adjust to new conditions.
Conclusion: Gliadin affected proliferation of some tested Lactobacillus strains. Taking into account previous scientific findings, it is very likely that the tested strains have an ability to hydrolyze gliadin and inhibit its toxic effects on intestinal cells. Lactobacillus species, along with some other lactic acid bacteria, therefor offer a potential therapy for gluten-related diseases.
The equipment used in this work was acquired as part of the project “Research Infrastructure for Campus-based Laboratories at University of Rijeka”, financed by European Regional Development Fund (ERDF). This work was supported by grant of University of Rijeka "Preparation of samples for metabolic, proteomic and glycomic analysis", No. of support: 13.11.1.2.03 and Slovak Research and Development Agency under the contract No. APVV-15-0006.
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