Pterostilbene suppresses benzo[a]pyrene-induced airway remodeling

This study has two novel findings: it is not only the first to demonstrate inflammatory cytokines, which are produced by the bronchial epithelium after exposure to benzo[a]pyrene (BaP) and contribute to airway remodeling by increasing human bronchial smooth muscle cells (BSMC) proliferation and migration, but also the first to reveal that pterostilbene, a constituent of grapes and berries, reverses BaP-mediated airway remodeling. Human bronchial epithelial cell lines BEAS-2B and HBE135-E6E7 (HBE) were treated with BaP, and then the condition medium (CM) was harvested, which was then added to BSMC. Cultures of BSMC with BaP-BEAS-2B-CM and -HBE-CM increased BSMC proliferation and migration, which are major features in asthma remodeling. Exposure of BEAS-2B and HBE to BaP caused epithelial cells to produce inflammatory cytokines IL-8, which subsequently induced BSMC proliferation and migration. Moreover, pterostilbene is more potent than resveratrol in suppressing BaP-mediated airway remodeling. This study suggests that pterostilbene is capable of preventing BaP-associated asthma.