Abstract Body (Do not enter title and authors here): Background: Traditional combustible cigarette (combustible) use induces endothelial dysfunction accelerating cardiovascular disease progression. Young adults frequently use electronic cigarettes (e-cig) that is linked to impaired endothelial cell (EC) function. We aimed to use EC gene expression analysis to explore altered pathways across patterns of tobacco product use.
Methods: Healthy adults aged 18-45 who regularly use e-cig (sole or dual), combustible, and non-use controls were with forearm vein EC biopsy and magnetic bead purification. EC total RNA was isolated and profiled on a NextSeq sequencer. Samples with transcript integrity number (TIN) < 10 were removed, genes were filtered with edgeR::filterByExpr, and analyzed with DESeq2. Differentially expressed genes (DEGs) comparing each use group to the non-use group were defined as log₂ fold change >1 and FDR p<0.01. Pathway analysis was done via Gene Ontology database and analyzed using over-representation analysis with log₂ fold change >1 and p<0.05 and selected based on experimental observation.
Results: 64 adults were recruited with a mean age 26±7 years and 34% female. After exclusion of samples not meeting TIN-quality standards, 44 samples were available for analysis sole e-cig (N=13), dual use (N=7), combustible (N=10), non-use (N=14). Each use group revealed multiple DEG compared to non-use (Figure): sole e-cig (50 DEG), dual use (18 DEG), combustible (65 DEG) with 28 DEG shared between sole e-cig use and combustible use suggesting similar patterns of altered EC phenotype. Upregulation of 4 genes 1L1B, PTPRO RYR2, and CLEC4D was shared across all three use groups suggestive of inflammatory activation. Pathway analysis in e-cig alone use group showed multiple pathways related to inflammation and immunity enhanced compared to non-use.
Conclusions: Young adults who use e-cig along display evidence of enhanced inflammatory gene expression in isolated EC suggestive of vascular inflammatory activation. Patterns of altered gene expression with e-cig use demonstrated both shared and distinct components compared to combustible cigarette use. Further work is needed to determine the components in e-cig that contribute to altered EC phenotype.