Production of reactive oxygen species by intestinal epithelial cells triggered by interaction with probiotic microorganisms

ROMANIN D E; GONZALEZ MACIEL D; HIRIART Y; GARROTE G L; RUMBO M

Buenos Aires. Argentina

Congreso; Congreso Franco Argentino de Inmunología, LVIII Reunión Anual de la Sociedad Argentina de Inmunología; 2010

Sociedad Argentina de Inmunología

Kefir is obtained by fermentation of milk with kefir grains, a polysaccharide matrix hosting a complex mix of microorganisms including lactic-acid bacteria and yeasts. Kefir isolated and other probiotic microorganisms have been shown to down-modulate intestinal epithelial innate response on in vitro and in vivo models. However the mechanisms involved in this effect remain unknown. The aim of the present work is to test whether lactic acid bacteria and yeast isolated from kefir and control collection strains may induce the production of Reactive Oxygen Species (ROS) that may lead to a inhibition of ubiquitination of IkB, the inhibitor of the transcription factor NF-kB, which is involved in pro-inflammatory innate immune response. Using a fluorescent ROS-indicator dye carboxi-dihidro-diclhorofluorescein (Carboxy-H2DCFDA) on a Caco-2 intestinal epithelial culture we found that some of the bacterial strains as Lactobacillus brevis ATCC 8287 and Enterococcus faecalis induced a significant production of endogenous ROS. Despite none of the kefir isolated microorganisms tested show a significant induction of ROS generation, yeasts, which show a higher rate of immunomodulation, show less induction than bacteria. These results indicate that kefir-isolated microorganism may implicate other mechanisms to modulate intestinal epithelial inflammatory response.