PSIX-11 - Testing the anti-inflammatory effects of brewer’s yeast extract on macrophage cell lines in vitro

Abstract: Recent studies have demonstrated that brewer’s yeast may modulate gastrointestinal and immune health. Yeasts have been reported to contain bioactive components that possess anti-inflammatory properties in vitro and in animal models, but source of yeast and processing conditions are unique to each product and require testing. The objective of this study was to evaluate the anti-inflammatory effects of a novel brewer’s yeast product in response to a lipopolysaccharide (LPS) challenge using two macrophage cell lines (Raw 264.7 cells; J774A.1 cells) in vitro. Once cells were stable, they were exposed to one of the following treatments for 24 h: sterile phosphate-buffered saline (placebo), brewer’s yeast extract (low dose or high dose), LPS only (positive control), and LPS + brewer’s yeast extract (low dose or high dose). Quantitative real time PCR (qPCR) was used to analyze relative mRNA production of pro-inflammatory cytokines (IL-6, TNF-α, IL-1α and IL-1β) in response to the treatments. Statistical analysis was performed using the PROC MIXED procedure of SAS, testing for the main effect of treatment. Significance was declared as P≤0.05. As expected, LPS increased expression of IL-6, TNF-α, IL-1α and IL-1β to a greater (P < 0.05) level than that of the placebo and yeast treatments in both cell lines. The results also showed that brewer’s yeast treatment in RAW 264.7 cells led to greater (P≤0.01) mRNA expression of IL-6, IL-1α and IL-1β during LPS challenge compared with control (LPS only) cells. In J774A.1 cells, brewer’s yeast treatments reduced (P≤0.01) the mRNA expression of IL-1α and IL-1β during LPS challenge in a dose-dependent manner. However, no differences were observed in the mRNA abundance of TNF-α or IL-6 in J774A.1 cells. These findings suggest that the brewer’s yeast extract tested may possess anti-inflammatory effects in macrophage cell lines in vitro, although the responses varied across cell lines and yeast extract concentrations. Further research is needed to explore the potential applications of brewer’s yeast as an anti-inflammatory agent in the target animals of interest.