Excess zinc levels connected to oxidative stress
A team of researchers has found that biomarkers that reflect exposure to metals are elevated in e-cigarette users. They have also found that these biomarkers are connected to oxidative DNA damage.
The cross-sectional vaping biomarkers study analyzed the urine of nonsmokers, e-cigarette vapers, and traditional cigarette smokers to compare metal concentrations and biomarkers.
“Our study found e-cigarette users are exposed to increased concentrations of potentially harmful levels of metals—especially zinc—that are correlated to elevated oxidative DNA damage,” cell biology professor and research team leader Prue Talbot said in press materials.
Zinc is an important a dietary nutrient, playing a part in immune function, growth, and wound healing. However, too much zinc can cause disease, and both zinc excess and zinc deficiency cause cellular oxidative stress. In turn, this can cause diseases such as acute lymphoblastic leukemia, atherosclerosis, coronary heart disease, lung cancer, and pulmonary fibrosis, if left untreated.
Vaping Biomarkers Study: Why It Matters
Vapes or e-cigarette units include an atomizing unit, a battery, and refill fluid. E-cigarette aerosols may contain metals, and those metals mostly come from the metal components in the atomizer. For example, the atomizer might include brass clamps, nichrome wire, insulating sheaths, tin solder joints, and wicks. The atomizer also heats the e-fluid, and this process can impart metals into the fluid.
This study is the first attempt from researchers to analyze and quantify urinary biomarkers connected to metals that could affect and possibly hurt vapers. But what are biomarkers?
A biomarker is characteristic of a biological process, state, or condition that can somehow be quantified. For example, certain biomarkers such as proteins, missing genes, and mutations have been tied to cancer risk, so when doctors see them in patients, they know they should receive preventative care for cancer.
Other molecules may be biomarkers. Previous studies on e-cigarette use in humans have examined biomarkers of exposure, such as nicotine or nicotine metabolites. These biomarkers only prove exposure to the e-cigarette itself, not to actual harm.
The difference here is that these are biomarkers of potential harm, and that harm is linked to metal exposure. Specifically, the team studied 8-isoprostane, an indicator of the oxidative degradation of lipids; 8-hydroxydeoxyguanosine (8-OHdG), a biomarker of oxidative DNA damage; and metallothionein, a metal response protein. Compared to the levels in cigarette smokers, concentrations of each of these biomarkers were significantly elevated in e-cigarette users.
Supported by grants from the National Institutes of Health (NIH), the vaping biomarkers study focused on 53 participants, all from the Buffalo, New York, region.