C25-03 Chronic E-Cigarette Exposure of Adolescent Rhesus Macaques Leads to Alterations to Inflammation at Transcriptional, Metabolomic, and Histologic Levels

Introduction Globally and in the U.S., adolescents and young adults have the highest rates of e-cigarette use. There are chemical components in e-cigarette aerosols unique to this form of nicotine delivery system; thus, vaping may have unexpected repercussions on human health. Multiple studies in mice have demonstrated inflammatory changes and immunomodulation both locally in the lungs and systemically. Here, we describe the effect of chronic e-cigarette aerosol inhalation in adolescent non-human primates (NHP) on pulmonary inflammation. Methods Three male rhesus macaques (Macaca mulatta) aged 2-3 years were exposed to e-cigarette aerosols (JUULTM Virginia Tobacco, 59 mg/mL nicotine salts) for 60 min/day, 3 days/week for 25 weeks. Bronchoalveolar lavage (BAL), bronchial and nasal epithelial cell brushings, blood (PAXgene RNA), and plasma were obtained prior to exposure and after 4 and 6 months of e-cigarette aerosol exposure. At 24 hours before euthanasia, animals underwent sampling prior to lipopolysaccharide challenge in the right caudal lobe, and sample collection was repeated on the day of euthanasia. After euthanasia, tracheal and lung tissue were collected from each animal for histology. Control lung tissue was obtained from the biobank at UC Davis. Total RNA was isolated from blood, BAL cell pellets, bronchial cells, nasal epithelial cells, and lung tissue, and underwent RNA-seq at the UCSD IGM Genomics Center. Plasma samples were analyzed for metabolites using rapid liquid chromatography-mass spectrometry. Fixed and paraffin-embedded lung tissue were evaluated using standard stains (e.g., H&E, trichrome, and PAS) and scored by a histopathologist blinded to the exposures. Results Evaluation of lung tissue in e-cigarette-exposed NHP showed increased pulmonary inflammation and collagen deposition when compared to controls. RNA-seq of bronchial brushings at 4 months compared to baseline showed upregulation of multiple pathways, including cytokine, chemokine, TNF, NF-κB, and IL-17 signaling pathways. Analysis of NHP plasma for metabolites demonstrated 18594 separate peaks (852 identified metabolites). Plasma metabolites changed in the setting of chronic e-cigarette exposure at 4- and 6-month timepoints (see Figure), with progressive downregulation of ethyl glucuronide, TG (53:6) and TG (55:6), and upregulation of TG (46:3). Conclusions Chronic e-cigarette exposure promotes pulmonary inflammation in adolescent NHP, with enrichment of inflammatory signaling pathways in airway epithelium and increased inflammation and airway remodeling in lung tissue. Chronic e-cigarette inhalation also alters the systemic circulation, with hundreds of metabolites altered in the blood. These data are the first of their kind in an animal model with the highest physiological relevance to human vapers. This abstract is funded by: California National Primate Research Center (CNPRC) Pilot Award; Tobacco Related Disease Research Program (TRDRP) T34IR8251; VA Merit Awards 1I01BX006447 and 1I01BX004767; NIH NHLBI K24 HL155884 and R01 HL137052.