Mineral and/or metal content as critical determinants of particle-induced release of IL-6 and IL-8 from A549 cells

Mineral particles in occupational exposure and ambient air particles may ca use adverse health effects in humans. In this study the ability of differen t stone quarry particles to induce release of the proinflammatory cytokines interleukin-6 (IL-6) and interleukin-8 (IL-8) from human epithelial lung c ells (A549) was investigated. Size distribution within the PM10 fractions w as quite similar for all particle samples, whereas mineral content and meta l composition differed. Particles, containing minerals such as quartz, amph ibole, chlorite, and epidote, induced a marked increase in IL-6 and IL-8 re lease, Particles composed mainly of plagioclase were much less effective. T he most potent particle samples exhibited a relatively high content of tran sition metals such as iron. Exposure to identical masses or surface areas r esulted in the same order of potency among the different particle samples. Significant cytotoxicity was observed only at higher concentrations of part icle exposure. Thus, mineral composition and/or metal contents of particles from different stone quarries were critical determinants for the marked di fferences in potency to induce cytokine responses in human epithelial lung cells.