Influence of Different Nicotine Sources on Exercise-Driven Immune Responses of Peripheral Blood Monocytes

Tobacco smoking is closely associated with pro-inflammatory immunological alterations, whereas regular physical exercise is well known to lower systemic inflammations and related immune cell activities. The combined effects of smoking, nicotine pouch use, vaping, and exercise on individual immunological responses remain incompletely understood, especially in view of alternative nicotine delivery systems. In this study, we analyzed the immediate impact of different nicotine sources on exercise monocyte subsets in 16 human subjects using a four-arm cross-over design. Distribution of circulating CD14/CD16 monocyte subsets and expression of the monocytic checkpoint molecule PD-L1 (programmed cell death ligand-1) were analysed via whole blood flow cytometry measurements. Plasma cytokines were evaluated using membrane-based cytokine arrays and enzyme-linked immunosorbent assays (ELISA). Data revealed significant distributions of circulating monocytes subsets in response to nicotine consumption and physical stress. In contrast, exercise-driven increased monocytic PD-L1 was clearly attenuated following the consumption various nicotine delivery systems. Furthermore, significantly increased plasma growth hormone levels were detected in response to physical stress in combination with cigarette consumption. Our data clearly illustrates a significant influence of nicotine consumption on the cellular characteristics of circulating monocyte subsets and on proper exercise-driven immune responses within a short period of time, which makes the widespread trivialization of alternative nicotine sources questionable.