Peripheral inflammation and PSD-95 levels are associated with structural brain changes in individuals with nicotine dependence using e-cigarettes.

Abstract

The prevalence of electronic cigarette (e-cig) consumption has risen among adolescents and young adults, but its associations with systemic inflammation and brain structure remain unclear. This cross-sectional study included 215 participants categorized into four groups: individuals who use e-cigs exclusively (n = 48), those who exclusively use traditional cigarettes (n = 51), those who use both e-cigs and traditional cigarettes (n = 45), and healthy controls (HCs) (n = 71) group. Peripheral blood levels of high-sensitivity C-reactive protein (hs-CRP), glial cell marker S100β, neuron-specific enolase, and postsynaptic density protein-95 (PSD-95) were quantified. Gray matter volume (GMV) was assessed using voxel-based morphometry. Significant differences in GMV were observed in the right superior temporal gyrus (STG), Heschl's gyrus, thalamus, and cerebellum. Individuals who used e-cigs exclusively exhibited higher GMV in the right STG compared to those who used both e-cigs and traditional cigarettes but no significant difference relative to those who used traditional cigarettes exclusively. Peripheral levels of PSD-95, S100β, and hs-CRP also varied significantly across groups. Compared to HCs, individuals who used e-cigs had higher S100β, lower PSD-95, and lesser GMV in the right thalamus. Significant correlations were observed between these biomarkers and GMV in the right STG and thalamus. Additionally, PSD-95 levels were associated with nicotine dependence severity in those who used traditional cigarettes. These findings suggest e-cig consumption is associated with differences in brain structure and peripheral inflammatory markers, highlighting a potential relationship between systemic inflammation and brain GMV.