Chemical flavors in e-cigarettes may damage lung function

According to a new study by Harvard's Chen Zengxi School of Public Health, two chemical flavors commonly used in e-cigarettes may damage the function of cilia in the human trachea. 

Cilia form antennae and are found in 50% to 75% of the cells in the human respiratory tract. They play an important role in protecting the human respiratory tract from mucus and dirt, allowing people to breathe freely. Damage to ciliary function is associated with lung diseases such as chronic obstructive pulmonary disease and asthma.  e liquid flavors concentrate

Chemical flavors in e-cigarettes may damage lung function

"although the chemicals that add flavor to e-cigarettes are very common, their effects on people are unknown. Our new study suggests that these chemicals may destroy cilia, the first barrier to the lung, by changing the expression of genes associated with cilia formation and function, "said Quan Lu, associate professor of environmental genetics and pathophysiology. Lu and Joseph Allen are co-authors of this study. 

The results were published in Scientific Reports on February 1, 2019. 

Chemical flavors in e-cigarettes may damage lung function

Millions of people are using e-cigarettes and have recently set off a wave of e-cigarettes among school-age teenagers, attracting the attention of public health experts. In December, Jerome Adams, the director of the U. S. Department of Health, identified the use of e-cigarettes among teenagers as rampant. E-Liquid flavour

In previous studies, Allen and colleagues at the Chen Zengxi School of Public Health found that the main ingredients in more than 90 per cent of the e-cigarettes they tested were diacetyl and 2, 3-pentanedione. 

In addition to being used in electronic cigarettes, diacetyl is also used in food seasoning, such as cream popcorn, baked products and sugar used in microwave ovens, which can create many different flavors. Diacetyl is considered a safe food additive, but there is evidence that inhaling diacetyl can be harmful. Previously, diacetyl was linked to bronchiolitis obliterans. 

Chemical flavors in e-cigarettes may damage lung function

In the new study, the researchers used a new technical system that allows them to detect the effects of diacetyl and 2, 3-pentanedione on epithelial cells, which mimic the condition of epithelial cells in the human respiratory tract. The researchers exposed normal human bronchial epithelial cells to these chemicals for 24 hours. They found that both diacetyl and 2, 3-pentanedione affected changes in gene expression, which may impair the production and function of cilia. 

In addition, the researchers found that even low levels of diacetyl and 2, 3-pentanedione can affect gene expression, indicating that the current safety indicators for these chemicals are not perfect. There are no such indicators for e-cigarette users, the authors say. 

"Electronic cigarette users are inhaling seasoning chemicals that have not been safely tested," Allen said. Although some e-cigarette manufacturers claim never to use diacetyl and 2, 3-pentanedione, this raises a question: what flavor do they use with chemicals? In addition, if workers are warned of inhalation hazards, why do e-cigarette users not receive the same warning? "