Human mucosal in vivo transcriptome responses to three lactobacilli indicate how probiotics may modulate human cellular pathways

Abstract

Probiotic bacteria, specific representatives of bacterial species that are a common part of the human microbiota, are proposed to deliver health benefits to the consumer by modulation of intestinal function through largely unknown molecular mechanisms. To explore in vivo mucosal responses of healthy adults to probiotics, we obtained transcriptomes in an intervention study after a double-blind placebo-controlled cross-over design. In the mucosa of the proximal small intestine of healthy volunteers, probiotic strains from the species Lactobacillus acidophilus, L. casei, and L. rhamnosus each induced differential gene-regulatory networks and pathways in the human mucosa. Comprehensive analyses revealed that these transcriptional networks regulate major basal mucosal processes and uncovered remarkable similarity to response profiles obtained for specific bioactive molecules and drugs. This study elucidates how intestinal mucosa of healthy humans perceives different probiotics and provides avenues for rationally designed tests of clinical applications.gene regulation | host-microbe interactions | lactobacillus | transcriptomics | gut bacteria

Lactobacillus paracasei and Lactobacillus plantarum strains downregulate proinflammatory genes in an ex vivo system of cultured human colonic mucosa

“…In a different study, volunteers received Lactobacillus plantarum WCFS1 through an intraduodenal cannula from where biopsies were taken after 6 h. Authors found differences in the modulation of NF-jB-related pathways (Troost et al 2008;van Baarlen et al 2009). In a similar experiment performed with other probiotic species (Lactobacillus casei, Lactobacillus acidophilus and L. rhamnosus), the same authors suggested that mucosal responses related to immune response, homeostasis, cell proliferation, T h 1-T h 2 balance, wound healing and TNF response are differentially induced by the different probiotic strains (van Baarlen et al 2011). Doubtlessly, experiments carried out in humans provided a lot of information about the mechanisms of action of intestinal probiotics; however, the difficulties in the experimental setups and the need to obtain biopsies from volunteers are major drawbacks.…”

The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic

“…Widespread mechanisms can be associ ated with effects that are observed across taxonomic groups, such as inhibition of potential pathogens or the produc tion of useful metabolites or enzymes. 18,19 Other effects at the intestinal or extraintestinal level, including immune effects, are more likely to be strainspecific 20 and claims of such benefit can only be made for strains or species in which the mechanistic basis has been demonstrated. 21,22 In many cases, a given probiotic might exert several health promoting effects.…”

Effect of Probiotic Supplementation on Blood Pressure of Females with Gestational Diabetes Mellitus: A Randomized Double Blind Controlled Clinical Trial

“…Probiotics can reduce the effects of pregnancy complications associated with inflammation and high blood pressure (58,59). It has been shown that probiotics can modulate the expression of human genes in intestinal cells similarly to drugs used for high blood pressure (60). Meta-analysis on the effects of probiotics on serum lipid levels reported a significant decrease of 6.4 mg/dL for total cholesterol, 4.9 mg/dL for LDL, and 3.9 mg/dL for serum triglycerides (53).…”