Smokeless tobacco extracts modulate keratinocyte and fibroblast growth in organotypic culture

Smokeless tobacco is associated with pathologic alterations of the oral mucosa, yet its direct effects on human keratinocytes and fibroblasts in stratified squamous epithelium are not well-understood. We hypothesized that smokeless tobacco could modulate the growth of keratinocytes and fibroblasts in an in vivo-like, organotypic tissue model. To test this, we exposed organotypic cultures for 3 days to smokeless tobacco aqueous extracts and determined the changes in morphology and proliferation of human keratinocytes and fibroblasts. All smokeless tobaccos stimulated keratinocyte proliferation at low doses (0.25% w/v) and suppressed growth at higher doses (> 0.5% w/v). In contrast, smokeless tobacco extracts promoted fibroblast growth at all concentrations without inducing fibroblast turnover. Fibroblasts and keratinocytes, therefore, were differentially affected by smokeless tobacco extracts in an organotypic tissue model, suggesting incipient changes that may occur in vivo.