Electronic nicotine delivery systems exhibit reduced bronchial epithelial cells toxicity compared to cigarette: the Replica Project.

Introduction:
This text reports a multi-site replication study (ring study) aimed at verifying the results of three key published studies conducted by the tobacco industry regarding cytotoxicity induced by tobacco smoke and ENDS aerosols on a model of airway epithelial cells. The study sought to reproduce the reported methodological approaches and assess the reliability of measurements and robustness of conclusions.

Key Points:

* The study involved five laboratories and assessed the reproducibility of laboratory performances for cigarette smoke and ENDS aerosol exposure.
* Large variability in NRU cell viability was observed within some laboratories in performing ISO whole smoke and ISO vapor phase exposure.
* Linear regression analyses showed good reproducibility between some laboratories for ISO whole smoke and ISO vapor phase exposure.
* LaB-D showed no significant correlation with any other laboratory for ISO whole smoke, ISO vapor phase, and health Canada intense vapor phase exposure.
* The study found that in comparisons between products, only 1R6F differed significantly from other products in terms of NRU cell viability.
* The study found that there was no toxicity to lung cells from e-cigarette aerosol, supporting the findings of azzopardi et al.
* The study also found that exposure of cells to undiluted smoke or ThP aerosol, adjusted to reach the same amount of nicotine in media, were associated with 26.45% viability with smoke exposure versus 93.34% with IqOS and 95.04% with glo PRO compared to the air control.

Main Message:
The main message of this text is that the results of the replication study support the reduced potential of e-cigs relative to conventional cigarettes in an in vitro model of bronchial epithelial cells. The study also highlights the importance of aerosol dilution and normalization of data to better reflect cell functionality for achieving the most accurate results in future studies. additionally, the study demonstrates that ENDS are significantly less toxic compared to cigarettes, and the establishment of collaboration between scientists can expand teamwork and progress knowledge in the field of reduced risk non-combustible tobacco and nicotine products.

Caruso M, Emma R, Distefano a, et al. Electronic nicotine delivery systems exhibit reduced bronchial epithelial cells toxicity compared to cigarette: the Replica Project. Scientific reports. 2021;11(1):24182. doi:10.1038/s41598-021-03310-y