Research article focuses on how IECs respond to probiotic strain B. lactis HN019

Probiotics are a group of live microorganisms administered in adequate amounts which confer a beneficial health effect on the host. This bacterial community plays a pivotal role in human nutrition and health by promoting the supply of nutrients, preventing pathogen colonization and shaping and maintaining normal mucosal immunity. While the precise mechanistic basis of the beneficial effects of probiotics is obscure and will most likely vary depending on the strain and species used.

A research article to be published on May 14, 2010 in the World Journal of Gastroenterology focused their studies mainly on how Intestinal Epithelium Cells (IECs) respond to a widely used probiotic strain B. lactis HN019, in so doing to reveal the mechanism of immunomodulatory effect of B. lactis HN019. The research team is led by Professor Guo from Shanghai Jiao Tong University, school of medicine. Adhesion assays of B. lactis HN019 and S. typhimurium ATCC 14028 to INT-407 cells were carried out by detecting copies of species-specific genes with Real-time PCR. Ultrastructure research was further conducted by transmission electron microscopy. Interleukin-1β, Interleukin-8, Tumor necrosis factor-α gene expression were assessed while enzyme linked immunosorbent assay was used to detect IL-8 protein secretion.

The results showed that the attachment of S. typhimurium ATCC 14028 to INT407 intestinal epithelial cells was inhibited significantly by B. lactis HN019. It is also important to note that B. lactis HN019 could be internalized into the INT-407 cells. B. lactis HN019 attenuated both IL-8 mRNA level at baseline and S. typhimurium-induced pro-inflammatory responses. IL-8 secretion was reduced while IL-1β and TNF-α mRNA expression level was not changed at baseline after treated with B. lactis HN019.

As a probiotic strain, B. lactis HN019 could modulate immune system towards anti-inflammatory action and exclude enteropathogen adhesion, in so doing contributing to the homeostasis of the intestinal epithelium. This knowledge will contribute to offer, in the near future, new therapeutic means to counteract the inflammatory disorders observed in human inflammatory bowel disease.