B26-08 Impacts of Flavored E-cigarettes on Age-related Immune Dysfunction

Abstract Rationale Aging leads to changes in macrophage polarization, which is critical for maintaining immune homeostasis in the lung. Further, some shifts in macrophage phenotype with aging may be adaptive, while others contribute to maladaptive inflammation and dysregulated repair mechanisms. Overall, aging of the lungs is associated with chronic low-grade inflammation, or “inflammaging,” and increased susceptibility to respiratory disease. While flavored e-cigarettes are widely used and known to influence immune pathways, it remains unknown whether they exacerbate age-associated immune dysregulation. Here, we sought to define the effects of flavored e-cigarette vapor on macrophage polarization and age-related inflammatory signaling. We hypothesized that exposure to flavored e-cigarette vapor would accelerate immune aging by skewing macrophage polarization, modulating it towards a less active phenotype. Methods THP-1 monocytes were seeded at 600,000 cells/mL and differentiated into M0 macrophages with PMA (25nM) for 48h. E-cigarette vapor-exposed (EVE) media was generated by drawing JUUL aerosol (Mint, Mango, Menthol, and Tobacco flavors with 59mg/ml nicotinic salts), vehicle (propylene glycol/ glycerol), or vehicle-containing nicotinic salts at 59mg/mL into RPMI-1640. EVE was diluted to 50% and cells were exposed for 24 hours. M0 macrophages were returned to growth media or further polarized with LPS (100 μg/mL) and IFNγ (20ng/mL) to M1, and IL-4 (20ng/mL) and IL-13 (20ng/mL) to M2, for 24 hours. Supernatants were collected to quantify cytokines (CCL17, IL-6, IL-8, IL-10, TNFα). Results Cytokine profiles obtained via ELISA showed that M1 macrophages secreted higher levels of pro-inflammatory cytokines IL-8, IL-6, CXCL2, and TNFα relative to M0 and M2 macrophages. Among the flavored e-cigarette exposures, Mint consistently induced the highest cytokine levels, particularly TNFα and IL-6. Unflavored nicotine-EVE treatment induced lower responses than flavored conditions. M2 macrophages showed minimal cytokine secretion across all conditions. Conclusion These findings demonstrate that flavored nicotine-containing e-cigarette aerosol exposures alter cytokine release in M1 macrophages. This suggests that flavorants may contribute to immune dysregulation seen with aging, and support the concept that flavored e-cigarettes may exacerbate age-related lung inflammation. Further research is needed to define the molecular pathways by which e-cigarette components accelerate lung aging and impair immune homeostasis in older individuals. This abstract is funded by: NIH National Institute on Aging T35 grant AG026757, NHLBI T32HL1661272024, NHLBIK24 HL155884, VA Merit 1I01BX004767, TRDRP T30IP09652023