, or iPS cells. Human iPS cells are capable of
differentiating into several cell types, and enable scientists to study changes
in human cells, which otherwise would be difficult to obtain directly from a
Endothelial cells are cells that line the interior of blood vessels and have several important functions
formation of new blood vessels and promoting wound healing.
This is the first
study to use endothelial cells
derived from human stem cells
to directly analyze the effects of nicotine and added flavorings on their
structure and function.
E-Cigarettes on Endothelial Cells
- The study team looked
at the effects on stem cells derived endothelial cells of six different popular flavors
added to e-cigarettes namely fruit, sweet tobacco with caramel and vanilla,
tobacco, cinnamon, menthol and sweet butterscotch with nicotine levels varying
from 0, 6, and 18 mg/ml.
- They found that most flavors were moderately toxic to the
endothelial cells, but the menthol and
cinnamon flavored e-cigarettes markedly reduced the viability of cultured
endothelial cells even when the e-cigarettes did not contain nicotine.
- The e-liquids also increased the endothelial cell
concentrations of reactive oxygen species (chemicals that cause DNA damage) as
well as levels of molecules involved in programmed cell death.
- Addition of cinnamon
and menthol flavored e-liquids to the cell culture markedly affected the ability of the cells to
form new blood vessels necessary for wound
- The caramel and vanilla flavored e-liquids also disrupted
new blood vessel formation but not as severely as menthol and cinnamon flavors.
- Endothelial cells exposed to caramel, cinnamon and vanilla
flavors showed an increased uptake of low-density lipoproteins and lipids,
which increases blood vessel inflammation and injury as well as a decreased
ability for wound healing.
Certain effects of the different e-liquids were dependent on
the nicotine levels, but reduced migration of endothelial cells to the site
of injury and loss of viability were independent of nicotine levels suggesting that both nicotine and the
e-liquids had combined injurious effect on the blood vessels.
- On comparing the blood levels of nicotine in people after
smoking e-cigarettes with those who smoked traditional cigarettes, it was seen
that the nicotine concentrations in the
blood were similar in the two groups after smoking for 10 minutes at a constant rate.
The findings of the study suggest that e-cigarettes are not
safe for heart and blood vessels and can adversely affect the health of young
kids smoking e-cigarettes, believing them to be safe
According to Joseph Wu, MD, PhD, director of the Stanford
Cardiovascular Institute and professor of cardiovascular medicine and of
radiology, "Until now, we had no data about how these e-liquids affect
human endothelial cells. This study clearly shows that e-cigarettes are not a
safe alternative to traditional cigarettes. When we exposed the cells to six different flavors of e-liquid with
varying levels of nicotine, we saw significant damage. The cells were less
viable in culture, and they began to exhibit multiple symptoms of
In summary, flavoring liquids added to e-cigarettes cause significant damage to
heart and blood vessels and strict regulations should be enforced to control the use
of e-cigarettes especially among children. In fact, the FDA has ruled that only
tobacco, menthol and mint flavors can be sold at all shops while the other
flavors including cinnamon can only be sold at adult venues
- E-cigarette use, flavorings may increase heart disease risk, study finds - (https://med.stanford.edu/news/all-news/2019/05/e-cigarette-use-and-flavorings-may-increase-heart-disease-risk.html)