Does flow culture impact upon gut-probiotic interactions: A comparison with static culture

Conventional tissue culture models often lack physiological relevance. In this exploratory study, dynamic flow conditions were applied to 21-day cultured Caco-2 intestinal epithelial cells and their response compared with statically cultured counterparts. Host:microbiome interactions were also explored through co-incubation with Gram positive bacteria (Lab4 probiotics) or the Gram positive cell wall component, lipoteichoic acid (LTA).Under flow, Caco-2 cells displayed increased viability, mucin production and pH tolerance compared to cells under static conditions. Measurement of secretion rates of the pro-inflammatory cytokine, interleukin-8, showed that cells under flow were unresponsive towards stimulation with Lab4 or LTA that was in complete contrast to inductions observed under static conditions. Given that Gram positive bacteria are well tolerated within the healthy gastrointestinal tract, these data suggest that flow conditions may improve the physiological relevance of Caco-2 cells. This preliminary study encourages further work exploring the impact of flow on cell-based in vitro models.