Complete artificial saliva alters expression of proinflamma-tory cytokines in human dermal fibroblasts
Complete artificial saliva (CAS) is a saliva substitute often used as a vehicle for test articles, including, smokeless tobacco. We discovered, using polymerase chain reaction gene expression array analyses, that CAS increased gene expression for certain proinflammatory cytokines including interleukin 8 (IL8) and interleukin 1α (IL1α) within 5 hours of treatment in cultured normal adult human dermal fibroblasts. Expression of the vascular cell adhesion molecule 1 (VCAM1), a gene upregulated by certain proinflammatory cytokines including IL1α, was also increased. Furthermore, cytometric bead array assays indicate that CAS increased the release into the culture media of proinflammatory cytokines including IL8. These results suggest that constituents of CAS may induce a proinflammatory response in cultured human dermal fibroblasts. To elucidate which components of CAS alter the expression and release of proinflammatory cytokines, we investigated the following: α-amylase, lysozyme, acid phosphatase, and urea. Comparison of the effects of CAS and modified preparations of artificial saliva indicate that α-amylase is responsible for the CAS-induced changes in the expression and release of the proinflammatory cytokines in dermal fibroblasts. Further investigation, using colorimetric assays, shows that this response correlates with the enzymatic activity of α-amylase. Therefore, it is important to carefully evaluate the “vehicle effects” of CAS and its constituents in oral/dental research.