Early Signs of Atherosclerosis Found in Young Tobacco and E-Cigarette Users

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Young adults who smoke tobacco cigarettes (TCIGs) or electronic cigarettes (ECIGs) showed early signals of atherosclerosis compared with nonsmokers, according to new research published online July 6, 2023, in Arteriosclerosis, Thrombosis and Vascular Biology.

In the small, cross-sectional study, researchers found that proatherosclerotic signals—monocyte transendothelial migration and monocyte-derived foam cell formation—were elevated among participants who used TCIGs and those who used ECIGs compared with those who never used either.

“There is a large body of data informing our mechanistic understanding of atherosclerosis, a slowly progressive, inflammatory process in which circulating monocytes attach to endothelial cells, then migrate into the subintimal space, where they phagocytize oxidized lipids and become foam cells, generating the fatty streak,” wrote first author Theodoros Kelesidis, MD, PhD, associate professor of medicine at the University of California Los Angeles, and colleagues. “The role of tobacco cigarettes in increasing oxidative stress and inflammation, thereby accelerating this process, is widely accepted. Whether ECIGs, too, promote this process of monocyte transendothelial migration and foam cell formation is unknown.”

To investigate further, Kelesidis and colleagues used an ex vivo mechanistic atherogenesis assay to quantify proatherogenic changes, including monocyte transendothelial migration and foam cell formation. They used plasma and peripheral blood mononuclear cells from healthy participants who exclusively used ECIGs or TCIGs and compared proatherogenic changes with those observed among nonsmoking controls, according to the study abstract.

The primary outcomes were monocyte transendothelial migration (ie, % of blood monocyte cells that undergo transendothelial migration through a collagen gel) and monocyte-derived foam cell formation “as determined by flow cytometry and the median fluorescence intensity of the lipid-staining fluorochrome BODIPY in monocytes of participants in the setting of an ex vivo model of atherogenesis,” wrote Kelesidis and coauthors.

A total of 60 young adults (median age, 24 years; 31 women) were included in the current study.

Researchers found that monocyte transendothelial migration was increased among participants in the TCIGs group (median interquartile range [IQR] 2.30, 95% CI 1.29-2.82; P<.001) and those in the ECIGs group (median IQR 1.42, 95% CI 0.96-1.91; P<.01) compared with those in the nonsmoking control group (median IQR 1.05, 95% CI 0.66-1.24).

Also, investigators observed an increase in monocyte-derived foam cell formation in the TCIG arm (median IQR 2.01, 95% CI 1.59-2.49; P<.001) and in the ECIG arm (median IQR 1.54, 95% CI 1.10-1.86; P<.001) compared with nonsmokers (median IQR 0.97, 95% CI 0.86-1.22).

Moreover, monocyte transendothelial migration and monocyte-derived foam cell formation was higher among those who used TCIGs compared with ECIGs users with or without a history of tobacco smoking (P for all <.05), according to the study results.

“Future studies are necessary to determine whether these findings are attributable to a residual effect of prior smoking or are a direct effect of current ECIG use,” concluded Kelesidis et al.

Reference: Kelesidis T, Sharma M, Sharma E, et al. Chronic electronic cigarette use and atherosclerosis risk in young people: A cross-sectional study. Arterioscler Thromb Vasc Biol. Published online July 6, 2023. doi:10.1161/ATVBAHA.123.319172.