Six hours of exposure to cigarette smoke resulted in the near-complete death of cells tested, while the same exposure to e-cigarette vapor did not affect tissue viability.
Tested from two different types of e-cigarettes, the vapor produced had no cytotoxic impact on human respiratory tract tissue, according to a new study published in In Vitro Toxicology (DOI: 10.1016 / j.tiv .2015.05.018).
Scientists British American Tobacco et MatTek Corporation used a unique combination of tests to study the potential adverse effects of the vapor produced by the e-cigarette on the tissue of the airways and compared it to cigarette smoke. "Using a smoke machine and a lab-based test using respiratory tissue, it was possible to measure the irritant capacity of an aerosol and prove that the different aerosols present in the e-cigarette used in this study were ineffective. cytotoxic on respiratory tract tissues in humans "Says the spokesman Dr. Marina Murphy.
This new method could be used to help develop new standards for these types of products in the future.
The vapor produced by the e-cigarette can contain nicotine, humectants, flavors and thermal degradation products, so it is important to understand the potential impact on biological systems. Until now, there have been no studies proving potential adverse effects of e-cigarette vapor on in vitro models used which perfectly mimic the structure, function and exposure of normal human respiratory tissues.
The researchers combined a commercially available 3D model of respiratory epithelial tissue and the “Vitrocell” robot usually used for this kind of test with “smoke” to assess the irritation potential of e-cigarette vapor. of two commercially available models. The results show that, despite hours of continuous exposure, the impact of e-cigarette vapor on the tissue of the airways is similar to that of air. In addition, the study represents an initial move towards socialization and starts the debate on potential guidelines for the industry.
The airway tissue model " EpiAirway Comprises human tracheal / bronchial epithelial cells that have been cultured to form differentiated layers resembling epithelial tissue of the respiratory system. The system " Vitrocell »Mimics the exposure of an inhaling human by providing data on emissions produced from cigarettes or e-cigarettes. It can also simply return the inhalation to the tissues " EpiAirway"
The researchers first tested the biological system with known irritants applied in liquid form. Then they exposed the tissues EpiAirway to cigarette smoke and aerosols generated from two types of e-
cigarettes for six hours. During this time, cell viability was measured hourly using an established colorimetric test. The mass amount of particles deposited on the cell surface was also quantified (using dosimetry tools) to prove that smoke or vapor reached the tissue throughout the exposure.
The results show that the cigarette smoke reduces cell viability to 12% (close to complete cell death) after six hours. In contrast, none of the e-cigarette aerosols showed any significant decrease in cell viability. Despite 6 hours of continuous exposure, results were similar to control cells exposed only to air . And even with aggressive exposure, e-cigarette vapors do not reduce cell viability.
«Currently, there are no standards for in vitro testing of e-cigarette aerosols ”says Marina Trani, head of R&D for next generation nicotine products at British American Tobacco. But, she adds, “Our protocol could be very useful in helping the process to progress.»
This study shows that, in this model of human respiratory tissue, cytotoxicity is not affected by e-cigarette aerosols, but more studies will be needed to compare the effects of various other commercially available products, formats and formulations.
Source : Eurekalert.org
