Table 1.

Summary of probiotics effects on epithelial barrier function in vitro and in vivo.

Probiotic	Effect in epithelial barrier	Model	References
Bifidobacterium longum *	Increase the production of acetate and prevent the reduction in TEER resulting from E. coli O157-induced cell death.	Caco-2	Fukuda et al., 2011, 2012
Bacteroides thetaiotaomicron *	Acetate-producing bacteria, favors goblet cell differentiation and mucus secretion.	Rats	Wrzosek et al., 2013
Faecalibacterium prausnitzii *	Acetate consumer and butyrate-producing bacteria, modulates the intestinal mucus barrier when supplemented in combination with B. thetaiotaomicron.	Rats	Wrzosek et al., 2013
Lactobacillus casei **	Reverses the cytokine-induced dysfunction of TEER, epithelial permeability, and ZO-1 expression.	Caco-2	Eun et al., 2011
B. animalis ssp. lactis CNCM-I2494**	Protects barrier integrity by restoring intestinal permeability, colonic goblet cell populations, and cytokine levels. Furthermore, normalizes the level of several TJ proteins, in particular claudin-4.	Mice	Martín et al., 2016
Lactobacillus plantarum ZLP001*	Modulates butyrate-producing enteric microbiota to induce the expression of epithelial host-defense peptides and to enhance intestinal Lactobacillus abundance to improve the gut microbiota composition and reinforce TJs.	Weaned piglets	Wang et al., 2018
L. acidophilus * Streptococcus thermophilus *	Increases TEER, decreases permeability, and induces the activation of occludin and ZO-1, shown by increased levels of phosphorylated proteins.	Caco-2 HT-29	Resta-Lenert and Barrett, 2003

^*Probiotics that are part of the human intestinal microbiota.

^**Probiotics that, normally, are not present in the human intestinal microbiota.