Abstract
The ciliated epithelium of the respiratory airways is one of the first vital systemic surfaces in contact with the ambient air. Ex vivo nasal epithelial ciliary beat frequency (CBF) at room temperature is on the order of 7-8 Hz but may be stimulated by irritant exposure. The upregulation of CBF in response to acute irritant exposure is generally considered to be a transient event with eventual return to baseline. However, studies of CBF dynamics in response to typical lifestyle exposures are limited. This study assessed nasal epithelial CBF among human subjects as a function of quantifiable lifestyle tobacco smoke exposure. Nasal epithelial biopsies were obtained from human subjects with well documented histories of tobacco smoke exposure. CBF was determined using a digital photometric technique and concurrent assays of nasal nitric oxide and urine cotinine and creatinine were performed. Mean CBF among active smokers and non-smokers exposed to environmental tobacco smoke (ETS) was elevated over non-smokers. Although there were dramatic differences in relative levels of tobacco smoke exposure, CBF values among tobacco smoke-exposed groups were comparable. Parallel in vitro studies of cultured nasal epithelium exposed to cigarette smoke condensate further supported these observations. These studies suggest that persistent elevation in nasal epithelial CBF is an early, subtle, physiologic effect associated with lifestyle tobacco smoke exposure. The molecular mechanisms that upregulate CBF may also create a cell molecular milieu capable of provoking the eventual emergence of more overt adverse health effects and the pathogenesis of chronic airway disease.