A recent study from UCSD’s School of Medicine and the Veterans Affairs San Diego Healthcare System indicates that e-cigarettes are toxic to human airway cells, suppress immune defenses, alter inflammation and boost bacterial virulence. The data was published in the Journal of Molecular Medicine on Jan. 25.

The researchers tested the consequences of smoking e-cigarettes, also known as “vaping,” by exposing mice to e-cigarette vapor for extended periods of time. Senior Author, Staff Physician at the VA San Diego Healthcare System and Assistant Clinical Professor at UCSD’s School of Medicine Laura Crotty Alexander told the UCSD Guardian that the changes in the mice were similar to that of people who get sick from smoking traditional cigarettes. The inflammatory markers — signs of full-body inflammation — of exposed mice were 10 percent higher than those of the unexposed ones.

“The study showed that if you inhale e-cigarette vapor for an hour a day, five days a week for a month, your lungs do change,” Crotty Alexander said. “We found in the blood evidence of inflammation, which is a marker seen in people who have heart disease, lung disease and kidney disease.”

The results also suggested that bacterial pathogens benefit from exposure to e-cigarette vapor. In particular, the process enhanced the ability of Staphylococcus aureus bacteria to form biofilms, resist human antimicrobial peptides and invade airway cells.

Mice with pneumonia were also found to be less likely to survive if they were exposed to e-cigarette vapor. All of those that were infected with normal methicillin-resistant S. aureus, known as an antibiotic “superbug,” survived. However, 25 percent of those that were pre-exposed to e-cigarette vapor died.

The researchers found similar results in multiple e-cigarette brands, though none of them match the level of change that traditional cigarettes cause.

“It looks like e-cigarette vapor across brands are causing human cells to behave differently but to a lesser extent than cigarette smoke,” Crotty Alexander told the Guardian. “Each brand is slightly different, but they all, in general, are causing problems, which suggests that there is a common ingredient or a common pathway.”

Though much of the research done on e-cigarettes is compatible with the results of her team’s study, Crotty Alexander warned that many studies are financed by e-cigarette companies and may be misleading.

“In the world of e-cigarette research, you have to be really careful when you read a paper or look at an article that has come out to see who was doing that research,” Crotty Alexander said. “There are many studies that are done where the e-cigarette company gave money or gave supplies, so there’s an inherent bias in the data out there. But if you look at the stuff that has come out of reputable institutions, the results of our study fit in with what people are finding.” 

However, Crotty Alexander assured the Guardian that her team intends to improve the ingredients and design of e-cigarettes so that they are safer to use as well as to demonstrate why vaping is harmful. Furthermore, she cautioned potential e-cigarette users from picking up the habit before all of the research is in, pointing to how long it took for scientists to find out how dangerous smoking traditional cigarettes are.

“The overall goal of our research is to identify dangerous things about e-cigarettes and find ways to make them safer,” Crotty Alexander said. “With cigarette smoke, we didn’t really understand that it was causing cancer, heart disease and kidney disease for about 50 to 60 years. We don’t want somebody to start vaping now and then develop cancer in 40 to 50 years.”

Crotty Alexander and her team will continue their research on e-cigarettes by exposing mice to e-cigarette vapor for longer periods of time, which she hopes will provide insight into the long-term effects of vaping.

“That should give us a lot more information about what kind of changes might occur over time in all the different organ systems of the mouse,” Crotty Alexander said. “We’re specifically interested in the inflammatory changes because cigarette smoke definitely causes a lot of lung damage and issues with inflammation; we want to know whether that is a problem in e-cigarette use as well.”