Plant sterols (PS) exert hypocholesterolemic effects and prevent cardiovascular diseases. In addition, PS have evidenced immunomodulatory properties promoting anti-inflammatory( Reference Othman and Moghadasian 1 ) and both innate and adaptive immune response(s)( Reference Brüll, Mensink, van den Hurk, Duijvestijn and Plat 2 ). It is known that PS are susceptible to oxidation increasing their cytotoxicity; however, the influence of oxidized derivatives on inflammation and immune response(s) has been poorly evaluated and, in in vitro models, only in monocytic (U937) cells( Reference Vejux, Montange and Martine 3 ). The objective of the present study was to compare cytokine profiles in intestinal epithelial (Caco-2) cells exposed to 7-ketostigmasterol and 7-ketocholesterol. Caco-2 cell cultures (initial density of 50.000 cells/cm2) were challenged (5 days post-seeding) to solutions (60 μM) of 7-ketostigmasterol or 7-ketocholesterol for 3h. Relative changes in the expression (mRNA) of IL-1β receptor, TNF-α and NFκB (p65) were monitored by reverse transcription-qPCR, and interleukin (IL)-8 and IL-10 production were quantified by ELISA. Cell cultures exposed to 7-ketostigmasterol exhibited a sharp up-regulated expression of IL-1β receptor, TNF-α and NFκB (Fig. 1A). This cellular response(s) was accompanied of a marked increase in IL-8, but slight IL-10, production (Fig 1B). These results indicate potential negative alterations in intestinal permeability favoring the interaction with intraepithelial lymphocytes. 7-ketocholesterol only induced a moderate up-regulation of IL-1β receptor and significant lower concentrations of IL-8 than 7-ketostigmasterol.
The results evidenced that 7-ketostigmasterol caused more severe inflammatory response(s) than 7-ketocholesterol to Caco-2 cells cultures. The potential negative impact of 7k-stigmasterol on intestinal epithelium integrity could alter its morphological functionality.