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This study has shown a significant difference in the way the human heart cells, especially the human coronary artery endothelial cells (HCAEC), respond to E-cigarette smoke and to the conventional cigarette smoke.
E-cigarettes are designed in such a way that they dispense the main component of cigarette smoke, nicotine, in the form of an aerosol as compared to the conventional cigarette in which the smoke is directly inhaled. The level of harmful chemicals dispersed via the E-cigarette aerosol depends on different factors such as the solution used and the battery output voltage.
The general consensus about E-cigarettes is that they are less harmful as compared to the conventional cigarettes since the smoke is not directly inhaled but there is a lack of enough data to back up this point of view. This called for a need to investigate the biological effects of E-cigarettes on various organ systems of the body and to compare them against the effects of conventional cigarettes at a very basic cellular level.
E-Cigarettes Are Less Stressful For Heart
The study was carried out by researchers at the Medical Research Council Integrative Epidemiology Unit (MRC IEU) at the University of Bristol. The basic aim of the study was to observe the stress response of the human coronary artery endothelial cells (HCAEC) when exposed to E-cigarette smoke and conventional cigarette smoke. The results of the study were later published in the journal Drug and Alcohol Dependence.
During the course of the study, the researchers obtained aqueous filtered extracts of conventional cigarette smoke. The extract was prepared by passing the smoke from a cigarette through 10 ml of endothelial cell growth media MV2.
The researchers also prepared an aerosol extract from the E-cigarettes (eCAE) by employing the same tools. 5 cycles of 5 seconds of heat were used allowing at least 10 seconds in between the puffs which permitted the coils to cool down. Air was drawn through the device at a rate of 70 ml/minute during the process. The strength of the nicotine solution was 18 mg/ml. Cultures of heart cells were prepared and were exposed to both extracts.
The research team then assessed the pattern of gene expression of the human coronary artery endothelial cells (HCAEC) to analyze whether the heart cells show a stress response to the E-cigarette aerosol extract or to the conventional cigarette smoke extract. The genes that were studied included the oxidative stress sensing transcription factor NFR2 (nuclear factor, erythroid 2-like 2, NFE2L2), and the cytochrome P450 family members.
According to Professor Marcus Munafò, one of the research team members, it was observed that heart cells exhibited a stress response when exposed to the conventional cigarette smoke extract through activation of NRF2 and up-regulation of cytochrome p450, but not to the E-cigarette aerosol extract.
The study established that E-cigarette is a viable option for tapering off nicotine addiction in people trying to quit smoking. It also suggested that the tobacco users can use E-cigarettes to avoid the immediate harms associated with conventional cigarette smoking, particularly the cardiovascular risks.