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Integritet crijevne barijere je preduvjet za pravilno funkcioniranje sluznice crijeva, koja je odgovorna za povećanje kapaciteta apsorpcije bez narušavanja efikasnih obrambenih mehanizama uslijed kemijskih i mikrobioloških izazova. Sve je više dokaza da je poremećaj integriteta epitelne barijere jedan od glavnih uzročnih faktora koji se mogu povezati sa nekolicinom gastrointestinalnih bolesti, uključujući infekciju patogenima, pretilost, dijabetes, upalnu bolest crijeva, sindrom iritabilnog crijeva i nekrotizirajući enterokolitis. Sve je više dokaza da probiotički sojevi bakterija mliječne kiseline (BMK) mogu utjecati na integritet crijevne barijere, zbog čega su veoma aktualna istraživanja u kojima se in vitro eksperimentima na staničnim linijama, ispitivanjima na pokusnim životinjama te kliničkim istraživanjima ispituje može li se probioticima postići vraćanje homeostaze te ozdravljenje osobe kod koje se primjenjuju. Među potencijalnim probiotičkim sojevima BMK ističu se vrste roda Lactobacillus, posebno oni sojevi koji na površini stanica eksprimiraju sloj specifičnih S-proteina. U ovom radu ispitana je sposobnost obnavljanja sloja S-proteina soja Lactobacillus brevis SF9B nakon prolaska kroz gastrointestinalni trakt te uloga S-proteina u kompetitivnoj ekskluziji bakterija Listeria monocytogenes ATCC 19111 i Staphylococcus aureus 3048 istim probiotičkim sojem u in vitro eksperimentima adhezije na crijevne epitelne stanice Caco-2 stanične linije. Intestinal barrier integrity is a prerequisite for homeostasis of mucosal function, which is responsible for increasing absorptive capacity without disturbing efficient defensive reactions against chemical and microbial challenges. Evidence is mounting that disruption of epithelial barrier integrity is one of the major aetiological factors associated with several gastrointestinal diseases, including pathogen infection, obesity, diabetes, inflammatory bowel disease, irritable bowel syndrome and necrotising enterocolitis. However, there are indications that probiotic strains of lactic acid bacteria (LAB) can positively affect intestinal barrier integrity, which led to increased intensity of researches in which in vitro cell lines, animal models and clinical trials assess whether probiotics, when applied in people, can revert to homeostasis and health. Among potential probiotic strains of LAB, species of the genus Lactobacillus stand out, especially strains which express layer of specific S-proteins on the cell surface. In this work, the ability of probiotic strain Lactobacillus brevis SF9B to regenerate the layer of S-protein after exposure of the cells to stimulated conditions of gastrointestinal tract was examined. The role of S-protein in competitive exclusion of bacteria Listeria monocytogenes ATCC 19111 and Staphylococcus aureus 3048 with the same probiotic strain in in vitro experiments using intestinal epithelial cells of Caco-2 cell line was also tested. |
