Abstract LB-159: The association of alveolar lipid laden macrophages with inflammatory cytokines in electronic cigarette users

Abstract

Abstract Introduction: Lipid laden macrophages (LLM) from lung bronchoscopies have been identified as characteristic for some patients with e-cigarette (e-cig) or vaping product use associated lung injury (EVALI). While vaping with THC oils containing vitamin E acetate is thought to have caused the outbreak, there is a subset of the EVALI cases who reported vaping only with nicotine-containing e-cigs. A recent animal study showed that propylene glycol (PG) and vegetable glycerin altered lipid homeostasis and induced LLM. In addition to the associations with EVALI, understanding the health effects of vaping with e-cigs in general needs additional investigation. Objective: We examined alterations in alveolar lipid homeostasis comparing e-cig users to cigarette smokers and never-smokers. Further, we determined the association of LLM with inflammatory cytokines. Methods: LLMs, inflammatory cell counts, and cytokines were determined in bronchial alveolar fluids (BAL) from a cross-sectional study of 62 volunteer subjects, age 21-45. Participants who were e-cig users were either never-smokers or former smokers. Cigarette smoking and e-cig use were confirmed by biomarkers of exposure, including lung and urine cotinine and 3-hydroxycotinine and urine anatabine, nicotelline, and PG. Results: High LLM counts were found in the lungs of almost all smokers and about half of the e-cig users, but not in any never-smokers (P<0.001). LLMs were significantly correlated with the inflammatory cytokines IL-4 and IL-10 in e-cig users (P=0.01). Smoking history, including cigarettes per day and biomarkers of exposure, e-cig use history, and gender were not associated with LLMs (all P>0.05). LLMs were not related to THC exposure. Discussion: This is the first report comparing LLMs in the lungs of e-cig users with smokers and never-smokers. LLMs were found in lungs of both smokers and a portion of e-cig users. Given their presence among smokers, they are not likely to be useful as a marker identifying those with EVALI. However, LLMs may be one of the markers for specific disease risks associated with e-cig usage, but not smoking. Citation Format: Min-Ae Song, Peter G. Shields, Jo L. Freudenheim, Theodore M. Brasky, Joseph P. McElroy, Joseph P. McElroy, Sarah A. Reisinger, Daniel Y. Weng, Rongqin Ren, Thomas Eissenberg, Mark D. Wewers, Konstantin Shilo. The association of alveolar lipid laden macrophages with inflammatory cytokines in electronic cigarette users [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-159.