The Proof is in the Pudding

Temperance Rowell delves into the flavored world of e-cigarettes to investigate the long-term effects of a new trend.

Photo by Max Englund/UNC Health Care

By Mark Derewicz

T-bone steak, banana pudding, peach schnapps, piña colada, blueberry cobbler, peanut butter cup, Irish Cream, rum and coke, gummy bears, java jolt, and kiwi custard. This list is just a taste of the 7,000-plus flavors of electronic cigarettes available for consumption also known as vaping.

There’s just one problem. Although e-cigarettes are marketed as safe alternatives to regular cigarettes, and the Food and Drug Administration (FDA) has approved the ingestion of the known chemicals used in the flavored liquids of e-cigarettes, no one knows what happens when you inhale these chemicals over the course of a lifetime. And, in some cases, no one – not even the FDA – knows what chemicals are even in these products.

Enter graduate student Temperance Rowell and the lab of Rob Tarran, PhD, associate professor of cell biology and physiology. Rowell explores the chemical basis of e-cigarettes and their effects on the epithelial cells that line our lungs. So far, Rowell and Tarran’s team have found that not all e-cigarettes are made equal and the health effects might depend on whether you vape black licorice or blackberry chocolate or blackberry Italian cream soda.

She presented her preliminary findings at the 2015 American Thoracic Society International Conference, and her work was selected to be included in press materials stemming from the event. News of her research appeared in various outlets, including Wired magazine.

We sat down with Temperance for a Student Profile to discuss her research, how she got into this line of work, and why she chose UNC.

Name: Temperance Rebecca Rowell

Birthdate: December 9, 1989

Hometown: Lodi, California

Eduation: BS in biology at Cal State-Fresno / second-year PhD student, cell biology and physiology

Mentor: Rob Tarran, PhD, associate professor of cell biology and physiology

Overall goal: Elucidating the effects of e-cigarettes to inform public health policy

Dissertation: Understanding how the chemical components of e-cigarettes affect particular cellular components of the human airway

Extracurriculars: DNA Day Connect program, teaching and mentoring, SMART mentoring program, cooking, hiking


“I was into music as a kid, and I’ve played the piano since I was 5 years old. But my mom is a nurse and my siblings had some medical issues, so I’ve always had my mind on medicine, too. I was always interested in how science applied to new therapies. I realized in college that I didn’t want music to be my career. So I turned to science, majored in biology, and thought about the pre-med route.

“Fresno State had a couple of productive and funded biology labs on campus. The director of the honors program told me that if I wanted to pursue biology, I should join a lab. So I did, and I loved it.

“I worked on fish endocrinology and got interested in how organ systems communicate with each other – how cells interact with each other. During my undergrad experience, I knew I wanted to do something more, and I learned more about how I could do research in graduate school.”

Why UNC?

“I applied to a couple places in California, but my brother-in-law went to UNC as an undergrad. I visited my sister a couple times here and really liked the area. When I interviewed here, the one thing that really struck me was the collaboration. Everyone emphasized it and how you didn’t have to do a small project by yourself. You could do a larger project and interact with other researchers. Also UNC has a lot of labs that do translational work, which I was interested in. And translating the science from the lab into how people are affected over time is a big part of the project I’m working on now.”

Why the Tarran lab?

“My other rotations as part of the Biomedical and Biological Sciences Program (BBSP) were really good experiences, too, but Rob Tarran had a spot opening up and I was interested in the work he was doing. Rob does cell signaling. I really liked the atmosphere. It’s a big, fast-moving lab that works with other labs across campus, and Rob had this project coming up that I thought was interesting.”

What do you focus on?

“We study electronic cigarettes, or e-cigarettes, which involve a new kind of smoking called vaping, which some people think isn’t bad for their health But the products are not FDA-regulated. We don’t really know what effect they might have on people.

“E-cigarettes are typically filled with liquid substances – usually glycerin and propylene glycol – that are infused with different amounts of nicotine and flavorings. The liquids are heated over a coil, and as you breathe in, the liquid becomes vapor. Then the liquids condense in the lungs, and the nicotine enters the blood stream. Essentially, the vapor consists of aerosolized small particles with chemical constituents for flavoring and nicotine that may or may not be altered by the heat. We really don’t know yet.

“E-cigarettes don’t contain the tobacco and tar of traditional cigarettes, which is why they are marketed as safer. But because the FDA doesn’t regulate them, there are a lot of different vendors pushing a lot of different products. Some of them can be modified to provide a bigger nicotine hit.

“Last year, it was estimated that there were more than 7,000 unique flavors available and we don’t know how they’re different. Some companies are now reporting what they put into their products. A lot of these chemicals are food additives. The FDA’s own research shows that these chemicals are not necessarily toxic at levels of normal exposure, but that research focused on ingestion because we typically eat food additives. A lot of these things have not been tested for inhalation. And the digestive system is a lot different than the respiratory system.

“We don’t know the effects, and I think it’s important to find out and inform people.”

What has your research found?

“Well, first of all, I’m only in my second year. But we have done some interesting work so far. We exposed human epithelial cells to the liquids used in e-cigarettes before the liquids were broken down through vaporization. We found that there were dose- and flavor-dependent responses. Some of the cinnamon, menthol, and banana pudding-flavored varieties seemed a lot more harmful during our in vitro screens.

“At lower doses, some of these flavored liquids decreased the number of live cells in our samples. And we looked at signaling pathways [the pathways that reveal how cells respond to their surroundings]. We studied the calcium pathway, which controls a lot of different things, such as mucus secretion and ciliary function. [Cilia are hair-like parts of airway cells that move in unison to promote good lung health.] These are things that naturally happen when cells want to clear things from the airway. So we’re exploring these effects.

“Right now, we’re coming up with the protocols for studying these exposures, including how to study the effects of vaporizing the chemicals.”

Why study this?

“The airway epithelial cells are pretty resilient, which is why you don’t usually see the effects of smoking until later in life, after many years of exposure. We’re talking about the effects that are independent of nicotine.

“As with regular cigarettes, some people use e-cigarettes casually. Some people puff on them all day. Then, there are so many variables between products. This is why the research is needed. Companies are saying these are safe, but how do we know? The best way to find out is to conduct research.

“I think e-cigarettes will only get more popular. Right now, they’re viewed as a ‘healthy’ alternative to regular cigarettes. Well, that might be true, but why do we think that? Are we sure about that? It’s difficult to answer without scientific evidence. Maybe the effects are mild. Maybe they’re not. I just think we should all be informed.”

Have you talked to kids about this?

“Yes. I went to Ayden-Grifton High School near Greenville as part of DNA Day, and so I struck up a relationship with the people there. We didn’t discuss my work as part of DNA Day, but now I do monthly Skype sessions with an honors biology class. At first, I’d just talk to them about graduate school and how science affects all of us. But the teacher told me some of the kids vaped.

“I asked if I could talk about my research. I asked the students: If you think something is marketed as safe for you, why do you think that is? What do you rely on to make these decisions? The students found this approach interesting. They were interested in the ethics behind it all – if something wasn’t safe, why wouldn’t ‘they’ tell us? These are 15-year-old kids who have no reason to think that some of the things sold to us might not be so good.

“I think it’s important to note that we’re producing a generation of people that will, again, be hooked on nicotine. They will use these devices for life, and I don’t think you’ll see a lot of physical effects until later, which is what happened with cigarettes. It’s just that the effects will probably not be the same.

“And it’s not just kids who want to know. At the American Thoracic Society meeting, there were a bunch of doctors who came up to me wanting to know about our research because they know a lot of their patients use these devices.”

What does your future hold?

“This research project has been an eye-opening experience – looking into regulatory science, which is like an extension of outreach, which I’ve always been interested in. I came here with the intention of becoming a PI and doing bench work, as well as mentoring through the lab environment. But regulatory science is something else that I think I’ll be interested in pursuing.

“I’m interested in the public policies we’ll develop because of e-cigarettes, much like the policies put in place for regular cigarettes not that long ago.”

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