Methods
Ecig-AMs were prepared by bubbling aerosol through PBS. Human-derived MSCs or murine-derived macrophages were plated on smooth, rough-hydrophobic, or rough-hydrophilic Ti surfaces in media supplemented with ecig-AM. In macrophages, expression of inflammatory markers was measured by qPCR and macrophage immunophenotype characterized by flow cytometry after 24 hours of exposure. In MSCs, expression of osteogenic markers and inflammatory cytokines was measured by qPCR and ELISA, while alkaline phosphatase activity (ALP) was determined by colorimetric assay.
Results
Ecig-AM polarized primary macrophages into a pro-inflammatory state with higher effect on ecig-AM with flavorants and nicotine. Metabolic activity of MSCs decreased in a concentration dependent fashion and was stronger in ecig-AM containing nicotine. MSCs reduced expression of osteogenic markers in response to ecig-AM, but increased RANKL secretion, particularly at the highest ecig-AM concentrations. The effect of ecig-AM exposure was lessened when macrophages or MSCs were cultured on rough-hydrophilic substrates. Significance: Ecig-AM activated macrophages into a pro-inflammatory phenotype and impaired MSC-to-osteoblast differentiation in response to Ti implant surfaces. These effects were potentiated by flavorants and nicotine, suggesting that e-cigarette use may compromise the osseointegration of dental implants.
Significance
Ecig-AM activated macrophages into a pro-inflammatory phenotype and impaired MSC-to-osteoblast differentiation in response to Ti implant surfaces. These effects were potentiated by flavorants and nicotine, suggesting that e-cigarette use may compromise the osseointegration of dental implants.