Scientists found significant differences in the effect of e-cigarette vapor and tobacco cigarette smoke on lab-cultured heart cells. They found that tobacco cigarette smoke, but not vapor from e-cigarettes, triggered a stress response in the heart cells.

For their study, the researchers analyzed changes in gene expression in the heart cells as a result of having smoke extract from a conventional cigarette or extract from e-cigarette aerosol passed through them.

Researchers said they found the cells showed a stress response from the cigarette smoke extract, but not from the electronic cigarette aerosol extract. “This result suggests tobacco smokers may be able to reduce immediate tobacco-related harm by switching from conventional cigarettes to e-cigarettes,” said lead author Marcus Munafò, joint senior author and professor of biological psychology at University of Bristol.

The researchers caution, however, that due to some of the study’s limitations, their findings should be regarded as preliminary and need to be confirmed by future models.