E-cigarette use can alter hundreds of genes involved in airway immune defense

Credit: TheNorlo/Wikipedia

When we smoke cigarettes, dozens of genes important for immune defense are altered in the epithelial cells that line the respiratory tract. Several of these changes likely increase the risk of bacterial infections, viruses, and inflammation. Now, UNC School of Medicine scientists report that vaping electronic cigarettes alters those same genes and hundreds more that are important for immune defense in the upper airway.

"I was really surprised by these results," said lead researcher Ilona Jaspers, professor of pediatrics, and microbiology and immunology at UNC. "That's why we kept going back to make sure this was accurate."

The finding, published in the American Journal of Physiology, suggests that inhaling the vaporized flavored liquids in is not without consequences, at least on the level of epithelial cell gene expression - the critical process by which our give rise to proteins important for various functions in cells.

The discovery cannot yet be linked to long-term health effects of e-cigarette use or the risk of diseases usually associated with long-term cigarette smoking such as cancer, emphysema, or chronic obstructive pulmonary disease.

"We honestly do not yet know what long-term effects e-cigarettes might have on health," said Jaspers, senior author and director of UNC's toxicology curriculum. "I suspect that the effects of e-cigarettes will not be the same as the effects of cigarette smoking."

So far, though, the evidence suggests that long-term e-cigarette use will not be harmless.

E-cigarettes have only been on the market in the United States since 2006, and usage skyrocketed just a few years ago. The more than 7,000 flavors available in e-cigarettes are FDA approved, though that approval process was based on data generated for oral consumption, not inhalation.

To study what effects e-cigarettes have on genes that help our upper airways fight off potentially harmful pathogens, Jaspers' lab recruited 13 non-smokers, 14 smokers, and 12 e-cigarette users. Each participant kept a journal documenting their cigarette or e-cigarette use, and in collaboration with researchers from the University of California at San Francisco, Jaspers' team analyzed participant urine and blood samples to confirm nicotine levels and biomarkers relevant to tobacco exposure.

After about three weeks, researchers took samples from the nasal passages of each participant to analyze the expression of genes important for immune responses.

Visually and functionally, the epithelial layers of our nasal passages are very similar to the epithelial layers in our lungs. All along our airways - from our noses to the tiny bronchioles deep in our lungs - need to function properly to trap and dispatch particles and pathogens so we don't get sick. These epithelial cells are critical for normal immune defense. Certain genes in these cells must give rise to proper amounts of proteins, which orchestrate the overall . It has long been known that cigarette smoking modifies this gene expression, which is one reason researchers think smokers are more sensitive to upper respiratory problems.

Using the non-smokers as the baseline comparison group, Jaspers' team found that smoking cigarettes decreased the gene expression of 53 genes important for the immune response of epithelial cells. Using e-cigarettes decreased the of 358 genes important for - including all 53 genes implicated in the smoking group.

"We compared these genes one by one," Jaspers said, "And we found that each gene common to both groups was suppressed more in the e-cigarette group. We currently do not know exactly how e-cigarettes do this."

Jaspers said her lab's findings do not mean that smoking e-cigarettes is as bad as or worse than smoking regular cigarettes

"I think it is a mistake to try to directly compare cigarette smoking and e-cigarette use," Jaspers said. "We shouldn't ask 'smoking causes cancer; do e-cigarettes cause cancer? Smoking causes emphysema; do e-cigarettes cause emphysema?'"

She said that inhaling burnt tobacco and inhaling vaporized flavored liquids are fundamentally different, and it's more likely that e-cigarettes could induce different biological changes and play different roles in other respiratory problems.

"We know that diseases like COPD, cancer, and emphysema usually take many years to develop in smokers," Jaspers said. "But people have not been using e-cigarettes for very long. So we don't know yet how the effects of e-cigarette use might manifest in 10 or 15 years. We're at the beginning of cataloging and observing what may or may not be happening."

Next, Jaspers will study how epithelial cells in e-cigarette users respond to a flu vaccine. This, she said, could help her team measure the immune response of epithelial cells in smokers, non-smokers, and e-cigarette users.

"We just finished our collection of samples," Jaspers said. "We'll see."

Explore further

Put that in your e-cigarette and smoke it, or should you?

Journal information: American Journal of Physiology

Citation: E-cigarette use can alter hundreds of genes involved in airway immune defense (2016, June 20) retrieved 24 August 2019 from https://medicalxpress.com/news/2016-06-e-cigarette-hundreds-genes-involved-airway.html
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User comments

Jun 20, 2016
STOP with the half truths which are really just "dressed up lies". the compounds you post about in this article are present at levels of only approx. 5% or less than with cigs. if everyone who smokes today switched to vaping of some sort, tobacco deaths would CEASE in a generation. this bullchit "we don't know enough" is just a promotion of the status quo. SHAME ON YOU. you might as go work for the tobacco lobby with this bullchit.

Jun 21, 2016
Actually pporpoiseboy, I think this article on e-cigarettes is probably spot on. I smoked cigarettes for about 20 years during which I would average about one cold/year. Since switching to e-cigarettes about 2 years ago, I have been averaging about 2-3 colds/year. Not only that, but the colds last longer. I just got over my last one about a month ago. It knocked me on my butt for 4 days. I never had a cold that lasted longer than 2 days before or one that kept me in bed. The cold before that left a lingering cough for 3 weeks. With that being said, I still feel better now that I switched to e-cigs and won't ever go back to regular cigarettes, but you can't just ignore a study because you don't like the findings. There are still plenty of good things about using e-cigs over regular ones.

Jun 21, 2016
This study means nothing. No genes are not damaged. They were in a suppressed state. (inactive) There is nothing to indicate they would not become un-suppressed (active) if triggered to do so.

Jun 21, 2016
sorry debate, your personal experience means nothing. i posted FACTS. you are just unlucky. i was citing studies from the royal college of surgeons in the uk. they are the FIRST medical assn in the 60's to warn of the dangers of smoking while in the usa companies were still touting "health benefits".
my personal experience is that after only a week off cigs and using ecigs, my heart rate after heavy exercise ( 45 min on elliptical ) my heart rate went down 30 points. my resting heart rate went down as well and i find all physiclal exertion VERY EASY now. but i did not post that originally because i feel posting SCIENCE and not my personal experience is more helpful. this article is hogwash? how do you know? they post NOTHING about the amounts of chemicals involved. it would mess with their little article if they said ecigs have many of the same toxins as ecigs but at MUCH LOWER levels. the royal college said the levels are low enough they would pass food tests.

Jun 21, 2016
Did you read the article? Or get the point of my post? The article was not about what kind of possibly dangerous chemicals are in e-cigarettes. You do know that inhaling something and eating something are two different processes right? Passing food tests means nothing when you are consuming the product in a much different manner. We can of course agree that e-cigs are much safer than regular ones, but dismissing this study out of hand just because you can't handle that there are possible negative effects is downright silly. Of course it is easier to breathe when you stop inhaling tar. That doesn't mean that there aren't other consequences. Do you understand? My personal experience means a lot. Of course we don't base our findings strictly on personal anecdotal evidence, but we also don't just ignore those same experiences. How else do you reach possible conclusions without observing effects in users? Seriously? This isn't that difficult a concept to understand.

Jun 21, 2016
As far as my personal experience, you could set a clock to my immune system. I rarely ever get sick and when I do, it was the same experience every time whether it was the flu or a cold. Now those experiences were the exact same for 35 years. Ever since I switched to e-cigs, my colds have lasted longer and are more severe. Is that a coincidence? Perhaps, but it is also quite possible that e-cigs have had an effect. You can't just dismiss that anecdotal evidence out of hand and say you are the one stating facts, because you just aren't. You don't know the facts and neither do I. Do you understand?

Jun 21, 2016
i understand that the royal college of surgeons KNOWS the facts. if it is all the same to you, I will trust them and not your anecdotal "evidence".
do you understand?

Jun 22, 2016
Actually, the Royal College of PHYSICIANS (RCP) DOESN'T know the facts either. They have made very educated guesses based on their findings.

Read the actual words from the RCP.

"On the basis of available evidence, the RCP believes that e-cigarettes could lead to significant falls in the prevalence of smoking in the UK, prevent many deaths and episodes of serious illness, and help to reduce the social inequalities in health that tobacco smoking currently exacerbates."

Notice the use of the word BELIEVES? You don't believe something if you know it to be true.

Jun 22, 2016
"E-cigarettes and long-term harm - the possibility of some harm from long-term e-cigarette use cannot be dismissed due to inhalation of the ingredients other than nicotine, but is likely to be very small, and substantially smaller than that arising from tobacco smoking. With appropriate product standards to minimise exposure to the other ingredients, it should be possible to reduce risks of physical health still further. Although it is not possible to estimate the long-term health risks associated with e-cigarettes precisely, the available data suggest that they are unlikely to exceed 5% of those associated with smoked tobacco products, and may well be substantially lower than this figure."

It is likely to be small? That doesn't sound like factual advice, does it? I am not diminishing the opinion of the RCP at all, but it is just that, an opinion. Of course it is an opinion that should be respected because they are a respected organization which is more often than not, correct.

Jun 22, 2016
okay you win. i will keep using ecigs, you smoke your cigs, we will see who dies first. i already told you whom i trust and apparently that does not sit wll with you. i really don't care that much, so please don't respond so i get another email telling me there are more posts. i am interested in what some others think but i think as far as you and i go, we have already beaten a dead horse.

Jun 22, 2016
Ah, it all makes sense now. You have difficulty with reading. It is okay. Many people have that same problem. Did you miss this part in my original post???......

"With that being said, I still feel better now that I switched to e-cigs and won't ever go back to regular cigarettes, but you can't just ignore a study because you don't like the findings. There are still plenty of good things about using e-cigs over regular ones."

You really shouldn't keep your head in the sand. Wouldn't you like to know if your e-cigarette is harming you in some way? I sure do which is why I just don't ignore the findings of studies that suggest possible negative side effects. I look at the strengths and weaknesses of such studies and continually reevaluate my opinions. Continual expansion of personal knowledge and wisdom is good for you. Is a couple extra colds/year enough to switch back to a very deadly substance? Of course not, but it is good to know nonetheless.

Jun 23, 2016
hey go fuck yourself and this site. you think because of the name you give yourself it is true. you are a classic troll. on and on and on and on. you really had to go to the direct insult place, eh? stop with your nonsense. if you did not have the anonymity of the internet you would be the guy the regularly gets his ass kicked for running your mouth. so go ahead and sit around in your smug self assured "i argue better than everyone else" bullshit. not only DON'T i need prodding or suggestion from you, i excel BEYOND you, you smirking piece of shit. i was the one that brought the royal college study to YOUR attention, then you try to school ME with it. fuck you. i have no use or time for false prima donna bullshit from overly smug shit heels like you. glad to know that first of all HARDLY ANYONE even comes to this site, and then if one does come here they find you. fuck that. and you. i look formward to your inevitable reply which NO ONE will read.

Jun 23, 2016
Hahahaha....I guess I touched a nerve. I was already well aware of the RCP study and all of the studies done on e-cigarettes because I would personally like to know whether or not I am killing myself with my electronic cigarette. You excel beyond me? Cool. I am happy for you. The only thing I recommend is that you pay better attention to what is being written. By the way, we are on the same side. We both see the great value that e-cigarettes can offer to people who have difficulty quitting tobacco use. The whole point of my original post was for you to think about what the actual study is saying and not just dismiss it because it says something negative about e-cigarettes. I wasn't trolling in anyway. More knowledge is always beneficial. Good day!

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