Acute effects of electronic and tobacco cigarettes on vascular and respiratory function in healthy volunteers: a cross-over study

Objectives : To assess the acute effects of nicotine-containing electronic cigarettes versus tobacco smoking on vascular and respiratory function and circulating microparticles, particularly platelet microparticles (PMPs, biomarker of haemostasis/thrombosis) and endothelial microparticles (EMPs, biomarker of endothelial function). Methods : Heart rate (HR), blood pressure, reactive hyperaemia index (RHI, microvascular reactivity), augmentation index (arterial stiffness) and respiratory function were assessed in 20 smokers immediately before and after electronic cigarettes use and tobacco smoking. The number of microparticles was determined by flow cytometry using counting beads as a reference. Labelling with Annexin-V was used to detect the total microparticle fraction. EMPs were characterized as CD31+CD42- and PMPs as CD31+RCD42+. Results : HR increased after electronic cigarettes use and tobacco smoking (P< 0.001), whereas blood pressure remained unchanged (P> 0.05). RHI (P = 0.006), augmentation index (P = 0.010) but not augmentation index standardized to HR 75bpm (P> 0.05) increased with electronic cigarettes use but not with tobacco smoking. Following tobacco smoking, there was a significant increase in total microparticles (P< 0.001), EMPs (P< 0.001) and PMPs (P< 0.001). In contrast, electronic cigarettes were only associated with an increase in PMPs (P< 0.001), with no significant changes in the total microparticle fraction or EMPs (all P> 0.05). Peak expiratory flow significantly decreased following electronic cigarettes use (P = 0.019). Conclusion : Our results demonstrate that acute exposure to tobacco smoking as well as electronic cigarettes influences vascular and respiratory function. Where tobacco smoking significantly increased microparticle formation, indicative of possible endothelial injury, electronic cigarettes use induced vasoreactivity and decreased peak expiratory flow. These findings suggest that both electronic cigarettes and tobacco smoking negatively impact vascular function.