Effects of Lactic Acid Bacteria and Fermented Milks on Eicosanoid Production by Intestinal Epithelial Cells

ABSTRACT: Fermented milk products produced with probiotic lactic acid bacteria (LAB) have attracted interest due to their potential health benefits. Probiotic bacteria have a range of immunomodulatory activity, interacting with a variety of cell types in the immune system. Interactions with intestinal epithelial cells (IEC) are an avenue through which probiotics and their fermented milks can influence production of key immunoregulatory molecules, including cytokines and eicosanoids. The eicosanoids, which include the prostaglandins (PGs), are lipid mediators implicated in both acute and chronic inflammatory processes. The primary objective of this study was to determine the ability of probiotic LAB and their ferments to interact with IEC and influence their eicosanoid production. Effects of LAB and their milk ferments on prostaglandin E₂ (PGE₂) and prostaglandin F_2α (PGF_2α) production by human IEC lines were determined using a competitive enzyme immunoassay. LAB alone did not alter interleukin (IL)-1β-induced prostaglandin production by IEC. However, milk fermented with Lac-tobacillus (L.) rhamnosus strain R0011 significantly suppressed IL-1β-induced levels of PGE₂ and PGF_2α, an effect which was counteracted by the addition of strain R0011. Milk ferments prepared withL. acidophilus strain R0052 were less effective in down-regulation of PG production by IEC. Naltrexone, an opioid receptor antagonist, blocked the suppressive effects of L. rhamnosus R0011 milk ferments on PGF_2α production by IEC, suggesting that the bioactivity the ferments is opioid receptor-mediated. These findings support immunomodulatory potential of fermented food components through interactions with intestinal epithelial cells.