Effects of Multi-Strain Probiotics on Immune Responses and Metabolic Balance inHelicobacter pylori-Infected Mice

Chronic inflammation caused byHelicobacter pyloriinfection increases the risk of developing gastric cancer. Even though the prevalence ofH. pyloriinfection has been decreased in many regions, the development of antibiotic resistance strains has increased the difficulty of eradicatingH. pylori. Therefore, exploring alternative approaches to combatH. pyloriinfection is required. It is well-known that probiotic therapy can improveH. pyloriclearance. In this study,H. pylori-infected mice were treated withLactobacillus fermentumP2 (P2),L. caseiL21 (L21),L. rhamnosusJB3 (JB3), or a mixture including the aforementioned three (multi-LAB) for three days. All the lactic acid producing bacteria (LAB) treatments decreasedH. pyloriloads in the stomach andvacAgene expression,H. pylorispecific immunoglobulin (Ig) A, and IgM levels in stomach homogenates, as well as serum levels of interferon-gamma and interleukin-1 beta. The multi-LAB and JB3 treatments further restored the superoxide dismutase and catalase activities suppressed byH. pyloriinfection. Furthermore,H. pyloriinfection decreased serum concentrations of 15 kinds of amino acids as well as palmitic acid. The multi-LAB treatment was able to recover the serum levels of alanine, arginine, aspartate, glycine, and tryptophan, which are all important in modulating immune functions. In addition, butyric acid, valeric acid, palmitic acid, palmitoleic acid, stearic acid, and oleic acid levels were increased. In this study, multi-LAB revealed its ability to adjust the composition of metabolites to improve health. To date, the mechanisms underlying how LAB strains crosstalk with the host are not fully understood. Identifying the mechanisms which are regulated by LABs will facilitate the development of effective therapies for infection in the future.