Cigarette smoking is the leading cause of preventable death worldwide. While the number of smokers is falling, the incidence of e-cigarette use is rising; the health effects of these products are not fully elucidated. This gap in knowledge is critical in the setting of wound healing, where it is unclear if e-cigarettes cause less harm than traditional cigarettes. The role of inflammation is crucial to the differential health effects of combusted and e-cigarettes, in the vascular system and distal end-organ. Excessive systemic inflammation is central to the pathogenesis of much tobacco-related disease, yet available data suggests that despite this systemic pro-inflammatory state, the needed inflammatory response to wounding in distal tissues is diminished in smokers. The underlying mechanisms of imbalanced systemic inflammation (increased) and extravascular tissue inflammation (decreased) are not well understood in smokers, and it is unclear if this imbalance is similarly present in e-cigarette users. Recent study suggests that e-cigarette aerosol may be pro-inflammatory, and limited human evidence reflects increased systemic and pulmonary inflammation. Distal tissue data remain limited, with few in vitro, animal, and human studies. Better evidence is needed on the effects of e-cigarettes on inflammation.
This research projects recruits from an on-going, prospective, controlled study of cigarette smokers who are randomized to switch to e-cigarettes, continued smoking, or medicinal nicotine, and non-smoking controls. The researchers utilize a cutaneous punch biopsy model of distal tissue trauma to study the potential differences in inflammatory responses after wounding at the systemic and distal tissue level across product types. They are generating data on the effects of e-cigarettes relative to continued smoking, medicinal nicotine, and non-smoking on intravascular and extravascular, cutaneous level inflammation as described in the specific aims, shown below:
- Aim 1: To analyze cutaneous indicators of extravascular inflammation including a) Infrared thermographic imaging, b) digital imaging (tissue characteristics) and c) histology (immunohistochemistry, inflammation score) and to compare these measures among groups after wounding.
- Aim 2: To analyze inflammation in the vascular space and extravascular tissue using: a) cytokines / chemokines / lipid mediators, b) inflammatory pathway analysis, c) RNA seq / gene expression, and d) DNA methylation for differences among groups.