Project Summary
Nearly 16% of US young adults ages 18–24 report smoking cigars and a recent review documents
growing evidence linking this product to lung cancer, coronary heart disease, aortic aneurysm and COPD.
Similarly, epidemiological studies link waterpipe tobacco to these same diseases. To date, there are few
studies characterizing these tobacco aerosols with respect to toxicant chemicals, and limited information
regarding effects on target cells with respect to cytotoxicity, genotoxicity, inflammation, and immune
responses. Importantly, no comparative dose response studies to cigarettes have been conducted to study
these endpoints, a research gap that is imperative to address for providing pharmacodynamic outcomes for
these addictive nicotine-containing products. Our research will allow for establishment of strong evidence-
based policies to inform the public of their hazardous properties. The specific aims and research strategy
derive from these research gaps and address two of the scientific domains in the RFA, toxicity and health
effects. As mandated by the FDA, the studies are not mechanistic, but are designed to compare responses
and effects at the cellular level across tobacco products (cigarettes, cigarillos, and hookah). The central
hypothesis of this project is that cigarillo and hookah tobacco products will show significantly greater toxicant
properties and predicted health effects when compared to cigarettes. Building on more than two decades of
experience in characterizing the physical and chemical properties of complex aerosols, Aim 1 will provide the
most comprehensive characterization to date for hazardous chemicals linked to cancer and cardiopulmonary
diseases in aerosols from eight common hookah tobacco products. The extensive dose response
characterization of the TPM generated from aerosols of these products using standardized cytotoxicity,
mutagenicity, and genotoxicity assays will also provide key insight regarding the potency of these products for
causing toxicity and harm relative to our studies just completed for cigarettes and cigarillos. Through a battery
of short-term assays and biomarkers (cytokines, DNA adducts), Aim 2 will critically evaluate complete and
fractionated (particles and gas only) aerosols generated from cigarettes, cigarillos, and hookah products in
lung epithelial cells, cardiac cells, and endothelial cells. A cumulative hazard score for each product will be
derived. Aim 3 focuses on adaptive responses of lung epithelial cells in response to treatment of cells for 4-wk
with complete aerosols from one each of these tobacco products. Outcomes from results will include changes
in cytokine levels and pathway alterations that may impact immune response, signaling, invasion, and growth.
These studies should inform generalized responses of the large and small airway epithelium that could
demonstrate a pro-inflammatory environment and/or altered immune signaling documented in the literature to
be associated with mucous hypersecretion and/or emphysema.
