Abstract
Altered drug pharmacokinetics during inflammation or infection have been linked to elevated plasma concentrations of proinflammatory cytokines. Data on how these cytokines affect the expression and activity of intestinal drug transporters and, therefore, bioavailability of transported drugs, remain limited. Here, we used a novel human enteroid in vitro model to investigate the effects of key proinflammatory cytokines (ie, interleukin [IL]-1β, IL-6, tumor necrosis factor-α, and interferon-gamma) on the mRNA expression of major intestinal transporters and activity of intestinal breast cancer resistance protein (BCRP) and P-glycoprotein (P-gp). Differentiated enteroid monolayers (in 96-well plates) were treated for 48 hours with each cytokine individually or in combination (cocktail) at 0.1, 1, or 10 ng/mL, encompassing their pathophysiological plasma concentrations in various inflammatory conditions. In a concentration-dependent manner, the cytokine cocktail significantly reduced the mRNA expression of BCRP, P-gp, multidrug resistance proteins 2/3, organic solute transporter α/β, serotonin transporter, and organic anion transporter polypeptide 2B1, while increasing multidrug resistance protein4 mRNA expression. Among individual cytokines, IL-1β elicited the most pronounced effects. To quantify the effect of cytokines on mRNA expression and activity of BCRP and P-gp, these treatments, at 1 ng/mL of individual cytokines or the cocktail, were repeated in the Transwell format. The efflux ratio of nitrofurantoin (a selective BCRP substrate), after exposure to 1 ng/mL of each cytokine or the cytokine cocktail for 48 hours, was significantly reduced, whereas the efflux ratio of digoxin (a P-gp substrate) remained unchanged. SIGNIFICANCE STATEMENT: Proinflammatory cytokines significantly downregulate major intestinal drug transporter expression and breast cancer resistance protein activity in human enteroid monolayers, highlighting the potential impact of inflammation on oral drug bioavailability. These results can be used to populate physiologically-based pharmacokinetic models to predict transporter-mediated drug absorption under inflammatory conditions, guiding safer and more effective dosing regimens.