E-vapor aerosols do not compromise bone integrity relative to cigarette smoke after 6-month inhalation in an apoE-/- mouse model.

Introduction:
This summary will provide an overview of a study comparing the effects of electronic vapor (e-vapor) aerosols and cigarette smoke (CS) on bone morphology, structure, and strength in a 6-month inhalation study using an apoE-/- mouse model. The study aims to investigate the potential of e-vapor products as less harmful alternatives to cigarettes in situations where bone health is of importance.

Key Points:

* The study exposed 8-week-old apoE-/- mice to e-vapor aerosols from three different formulations, CS from 3R4F reference cigarettes, or fresh air for up to 6 months.
* Tibiae were analyzed using micro-computed tomography (µCT) imaging, biomechanics by three-point bending, and histological analysis.
* CS inhalation caused a significant decrease in cortical and total bone volume fraction and bone density compared to e-vapor aerosols.
* CS exposure also led to a decrease in ultimate load and stiffness, while e-vapor aerosol and Sham exposure did not significantly affect bone structural and biomechanical parameters.
* at the dissection time point, there was no significant difference in body weight, tibia bone weight, or length among the groups.
* histological findings revealed microcracks in cortical bone areas among all exposed groups compared to the Sham control.

Main Message:
The study suggests that e-vapor aerosols could potentially constitute less harmful alternatives to cigarettes regarding bone health. The bone-preserving effect of e-vapor aerosols relative to CS exposure supports this notion. however, further research is needed to understand the long-term effects of e-vapor aerosols on bone health fully. This study contributes to the growing body of evidence supporting the potential of e-vapor products as less harmful alternatives to cigarettes for adult smokers.

Reumann MK, Schaefer J, Titz B, et al. E-vapor aerosols do not compromise bone integrity relative to cigarette smoke after 6-month inhalation in an apoE-/- mouse model. archives of toxicology. 2020;94(6):2163-2177. doi:10.1007/s00204-020-02769-4