Behavior of the Lactobacillus fermentum UCO-979C strain encapsulated in carrageenan for its potential use in a non-dairy probiotic product as a preventive alternative for Helicobacter pylori infection
Helicobacter pylori infection is presently one of the most frequent chronic infectious diseases. Reports of the prevalence of this infection in Chile ranges from 60% to 79%. Most infected individuals remain asymptomatic; nevertheless, between 10 -15% of them develop gastric or duodenal ulcers or ade...
| Autor: | |
|---|---|
| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2019 |
| País: | Chile |
| OAI Identifier: | oai:repositorio.anid.cl:10533/246586 |
| Acceso en línea: | https://hdl.handle.net/10533/246586 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Naturales Ciencias de la Tierra y del Medio Ambiente Microbiología |
| Sumario: | Helicobacter pylori infection is presently one of the most frequent chronic infectious diseases. Reports of the prevalence of this infection in Chile ranges from 60% to 79%. Most infected individuals remain asymptomatic; nevertheless, between 10 -15% of them develop gastric or duodenal ulcers or adenocarcinoma and a small percentage will develop MALT lymphoma. A number of therapies, based on antibiotics, are presently available but they are associated to problems including the emergence of resistance to the antibiotics used and the adverse effects associated to the treatment, the risk of re-infection and the high cost of the antibiotic therapy. Depending on the population studied, eradication therapies fail in 20 to 80% of the cases. The lack of a vaccine to prevent or eradicate H. pylori infection has encouraged the search for new approaches to deal with this problem. Since H. pylori colonizes the gastric mucosa making use of multiple virulence mechanisms, it is desirable to have prophylactic agents able to avoid or reduce colonization, thus protecting the host. In this scenario, probiotics stand out as an emerging and attractive alternative to handle and to prevent gastrointestinal diseases. Probiotics act directly or indirectly, either modifying the endogenous microbiota or acting as immunomodulators. Foods supplemented with probiotics usually are dairy derivatives and occasionally homemade fermented vegetal products. Food supplemented with probiotics of human gastric origin to prevent H. pylori infection are not presently available in the market. One of the main technological problems to incorporate probiotics as supplements to non-diary foods is the low viability of microorganisms during the processing and storage of food in addition to the effect of enzymes, gastric acidity or the activity of bile salts in the gastrointestinal tract. Altogether, the expected benefit to be provided by probiotics is far from optimal. Encapsulation of bacterial strains, in natural polymers is a practical option to improve the viability of bacteria during production processing and during the passage through the digestive tract. The general aim of this work was to evaluate if carrageenan encapsulation of the probiotic strain Lactobacillus fermentum UCO-979C affected its probiotic properties and anti-H. pylori activity in order to used it, as a supplement for a non-diary probiotic food, as a preventive alternative to the infection by this pathogen. Therefore, carrageenan encapsulated probiotic L. fermentum UCO-979C strain was subjected to stress conditions to test its viability, probiotic properties and anti-H. pylori activity and compared with the same non-encapsulated strain. The antiadherent effect on H. pylori of the probiotic and of carrageenan was tested using cell lines and the prophylactic effect of the probiotic and of the polysaccharide were XII tested using an animal model (Mongolian gerbil). Moreover, the encapsulated and non-encapsulated probiotic was subjected to gastric simulated conditions using a Chilean standard diet, a test not previously done. In vitro results showed that carrageenan encapsulation of L. fermentum UCO-979C did not affected the probiotic properties, anti-H. pylori activity and viability of the probiotic strain and favored its survival under stress conditions such as low pH (3.0), bile salts (3%) and the enzymatic activity of pepsin. The in vivo assays showed that the probiotic and carrageenan mixture reduced, from 3 logs up to render it undetectable, H. pylori colonization in the stomach of Mongolian gerbils. Using simulated gastric conditions, either under fasting or providing a Chilean standard diet, it was shown that the probiotic and carrageenan collaborated to eliminate the pathogenic H. pylori SS1 strain making it undetectable after 1.5 or 2.5 h, respectively. Therefore, it can be concluded the carrageenan encapsulation of L. fermentum UCO-979C did not affected its probiotic properties, that carrageenan also contributed to the anti-H. pylori activity and that the administration of the probiotic under fasting (acidic environment) improves its anti-H. pylori effect when compared to the administration associated to the diet. |
|---|