Pathogenesis of Chronic Sinusitis in Relationship to Tobacco Smoke Exposure

Chronic sinusitis is one of the most prevalent chronic illnesses in the United States and a significant health concern in terms of public health care expenditure. We wish to learn more about pathogenic factors causing or contributing to chronic sinusitis. One of these factors is secondhand smoke (SS) exposure. However, several other factors are involved, including allergic, environmental, genetic and microbiologic factors and in any given patient, several of these factors may be contributing to the disease. One of our goals is to see whether specific patterns of inflammatory cells, cytokines or chemokines exist that can differentiate these causative factors and to help us to better understand their individual contributions to the disease.

Several inflammatory cells, cytokines and chemokines are present in chronically inflamed sinus tissue, and we believe they form the basis for the disease process. At present, we know very little about what drives them into the sinus tissues. We believe that the types of inflammatory cells, cytokines and chemokines elicited in this disease depend on the inciting stimulus.

Cigarette smoke has well-documented deleterious effects on respiratory mucosa that could promote the development of chronic sinusitis. These include reduction in normal mucociliary function; increased nasal airway resistance; induction of mucin gene expression and induction of chronic inflammation. In the proposed study, we will extend our previous findings to investigate the relationships between SS exposure and these inflammatory markers and also examine the relationship of these cytokines to the expression of particular mucins.

Extracts of cigarette smoke have been shown to induce numerous other proinflammatory effects on respiratory epithelial cells either in vivo or in vitro. In this study we will analyze the gene expression of inflammatory markers in a nasal mucosal biopsy. Our intent is to study sinusitis rather than rhinitis. Nonetheless, we will examine nasal rather than sinus mucosa largely owing to the difficulties posed by obtaining samples directly from the sinuses. Furthermore, recent consensus reports have emphasized the importance of viewing sinusitis as a continuum of nasal and sinus mucosal inflammation. These same arguments have been put forward in terms of the concept of "one airway, one disease" which has emphasized the commonality of mucosal inflammation seen in the upper airway (rhinitis, sinusitis) and the lower airway (asthma). The biopsies will come from the middle turbinate. The latter structure has the same pseudostratified columnar epithelium and a virtually identical appearance to that of maxillary or ethmoid sinus mucosa. We have used biopsies from the middle turbinate in several previous studies of chronic sinusitis, primarily as a comparative tissue representing "healthy" sinus mucosa.