Infant intestinal Enterococcus faecalis down-regulates infl ammatory responses in human intestinal cell lines

Abstract

AIM:To investigate the ability of Lactic acid bacteria (LAB) to modulate inflammatory reaction in human intestinal cell lines (Caco-2, HT-29 and HCT116). Different strains of LAB isolated from new born infants and fermented milk, together with the strains obtained from culture collections were tested. METHODS:LABs were treated with human intestinal cell lines. ELISA was used to detect IL-8 and TGF-β protein secretion. Cytokines and Toll like receptors (TLRs) gene expression were assessed using RT-PCR. Conditional medium, sonicated bacteria and UV killed bacteria were used to find the effecter molecules on the bacteria. Carbohydrate oxidation and protein digestion were applied to figure out the molecules' residues. Adhesion assays were further carried out. RESULTS: It was found that Enterococcus faecalisis the main immune modulator among the LABs by downregulation of IL-8 secretion and upregulation of TGF-β. Strikingly, the effect was only observed in four strains of E. faecalis out of the 27 isolated and tested.

Gut colonization by aerobic microorganisms is associated with route and type of nutrition in premature neonates

“…A multivariate analysis showed that enterococcal colonization was significantly more frequent with enteral feeding than with TPN. In vitro data suggest that GIT enterococci play a beneficial role because some strains of Enterococcus fecalis could suppress the proliferation of intestinal pathogens and thus prevent infection and the induction of inflammation [45]. Conversely, Candida albicans colonization was more frequent in neonates receiving TPN than in neonates receiving enteral feeds, a finding that was similar to previous reports [41,46], but this difference was not significant.…”

The Effect of Lactobacillus acidophilus PTCC 1643 on Cultured Intestinal Epithelial Cells Infected with Salmonella enterica serovar Enteritidis

“…Our findings agree with those previously reported by a study performed in Argentina [28]. In contrast, previous studies have shown that TLR4 expression in Caco-2 cells decreased after treatment with lactic acid bacteria [30,31], whereas Miettinen et al [32] found that Lactobacillus rhamnosus GG did not influence TLR4 expression.…”

Immunomodulatory effects of Lactobacillus plantarum on human colon cancer cells

“…L. plantarum also promotes intestinal epithelial homeostasis through an increased viability, as demonstrated by MTT, and inhibits cytokine-induced epithelial cell apoptosis as seen by TUNEL staining (data not shown). It is known that stimulation by commensal bacterial antigens is crucial for the normal development of the mucosal immune system and maintenance of gut homeostasis, but their role in intestinal physiology is incompletely understood [62], although the beneficial effects were consistent with an antiinflammatory state conferred by probiotics [63].…”