Published February 3, 2017
How do the lungs of e-cigarette users differ from those of non-smokers and people who smoke traditional cigarettes?
A pilot study awarded to a UB epidemiologist seeks to provide some answers to that question. It’s a question that’s taken on greater significance as more people use e-cigarettes, and as the U.S. Food and Drug Administration has assumed regulatory control over them.
“E-cigarette use is increasing rapidly, including among young people who never smoked cigarettes,” says Jo Freudenheim, UB Distinguished Professor and chair of the Department of Epidemiology and Environmental Health in the School of Public Health and Health Professions. Freudenheim is the principal investigator on the $100,000 grant from the Prevent Cancer Foundation, the only U.S. nonprofit organization solely devoted to cancer prevention and early detection.
Research on the effects of e-cigarettes is critically important given the lack of knowledge about the health impacts to users.
“There’s a lot of interest in understanding how e-cigarettes affect the body,” Freudenheim says. “The FDA, in particular, is very interested in data about the biological impact of e-cigarettes. This study will contribute to that. It’s only one piece of a puzzle, but it’s a potentially important piece.”
The predominant ingredients in e-cigarette liquids — often called “e-juice” — are nicotine, propylene glycol and/or glycerol. When used in food and cosmetics, the non-nicotine constituents are considered safe by the FDA. However, there is little knowledge of how these ingredients and their by-products affect human lungs when inhaled following the heating and aerosolizing process that takes place in e-cigarettes.
For this pilot study, Freudenheim and her colleagues will examine samples from the lungs of healthy smokers, non-smokers and e-cig users aged 21 to 30. The study participants underwent a procedure called a bronchoscopy, where a sample of lung cells was collected by a rinse procedure. The investigators are studying whether there are differences in DNA methylation among the three groups. They will study 450,000 spots on the tissue DNA.
“Every cell in your body has the same DNA, but some parts of that DNA are turned on in different tissues — for example, for one cell to become a hair cell instead of a stomach or lung cell. Changes in DNA methylation contribute to allowing for those different kinds of cells,” Freudenheim explains.
“In tumors, one of the things that can happen is that DNA methylation can go awry — something that’s not supposed to be turned on is turned on or turned off when it should be turned on. We know that there are these kinds of changes in lung cancers and also that some of these differences in DNA methylation are seen in apparently healthy smokers. The point of this study is to find out how the DNA methylation in e-cigarette users compares to the other two groups,” she says.
Freudenheim’s study will build off of another pilot study recently begun by Peter Shields of The Ohio State University College of Medicine, a co-principal investigator on the Prevent Cancer Foundation grant. The goal is eventually to apply for funding for a larger study.
Min-Ae Song of The Ohio State University is a co-investigator. Dominic Smiraglia, associate professor of oncology at Roswell Park Cancer Institute, is a consultant on the UB study.
Freudenheim has long been interested in DNA methylation, focusing mostly on breast tumors, while Shields has extensive experience researching tobacco and e-cigarettes. They have collaborated for more than 20 years on research regarding ways to prevent cancer.