The third phase of the Replica project is in the prime of its activity: CoEHAR researchers successfully replicated the study published by Rudd and colleagues in 2020 and the data obtained not only show slight or no cytotoxic, mutagenic and genotoxic effects induced by the e-cigarette aerosol, but the work by researchers of Catania covered some methodological gaps and limitations in the original work.
For the assessment of toxicological potential of e-cigarettes, international guidelines recommend the use of a battery of in vitro tests. Unfortunately, the use of various research methodologies leaded to different data: faulty results are ill-informing policies and affect both health and social care practices and smokers who want to quit.
Replica researchers wanted to fill the methodological gap by independently reproducing some of the most relevant studies in the field in order to verify the robustness and replicability of the data.
In the last phase of the Replica project, scientists focused on some of the well-known international studies published to evaluate the toxicological potential of combustion-free products compared to that of conventional cigarettes.
The latest study replicated by the team is one published by Rudd and colleagues in 2020, which aims to establish the aerosol-induced cytotoxicity, mutagenesis and genotoxicity of a pod system e-cigarette aerosol compared to tobacco cigarette smoke.
Thank to the study “Cytotoxicity, Mutagenicity and Genotoxicity of Electronic Cigarettes Emission Aerosols Compared to Cigarette Smoke: the REPLICA project”, Replica researchers confirmed the results of the original works, showing slight or no cytotoxic, mutagenic and genotoxic effects induced by the e-cigarette aerosol. Moreover, the study covered some methodological gaps and limitations in the original work, due to in vitro exposure systems to aerosol and cigarette smoke not capable of reproducing the in vivo exposure conditions used by the authors of the original study.
“Our findings not only confirmed the results obtained by the colleagues, covering some methodological gaps and limitations in the original work” stated Rosalia Emma, first author of the study “Moreover, this replication study supports the tobacco harm reduction strategy as having the potential to substantially reduced exposure to toxic combustion agents in adult smokers”.
As in the original paper, the Replica team performed Neutral Red Test (NRU) for the evaluation of cytotoxicity, AMES test for the evaluation of mutagenesis and In Vitro Micronuclei (IVM) assay for the evaluation of genotoxicity on cells treated with cigarette smoke or e-cigarette aerosol.
The tests aim to establish the aerosol-induced cytotoxicity, mutagenesis and genotoxicity of a pod system e-cigarette aerosol compared to tobacco cigarette smoke. Despite some different methodological aspects in the Replica study, such as the use of a different reference cigarette because the one in Rudd study is no longer produced and the different smoke/aerosol ALI exposure in vitro system, due also to advanced machinery and equipment within the network of laboratories of the Catania research center, CoEHAR researcher obtained similar results to those of the original study.
The Replica research showed high cytotoxicity, mutagenicity and genotoxicity induced by cigarette smoke, but slight or no cytotoxic, mutagenic and genotoxic effects induced by the e-cigarette aerosol. Moreover, CoEHAR researchers can affirm that the results obtained by Rudd and colleagues have been established and their data also confirm the idea that e-cigarette aerosol is much safer and less harmful than e- cigarette smoking, making it a useful device in smoking harm reduction.