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E-Cigarettes Change Hundreds of Immune Genes

Scientists have known for years that cigarettes alter genes in the respiratory tract that are vital to defend the body against bacterial infections, viruses, and inflammation.

Now, researchers at the University of North Carolina School of Medicine found that vaping electronic cigarettes alters those same genes and hundreds more that are important for immune defense in the upper airway.

The study, published in the American Journal of Physiology, suggests that inhaling the vaporized flavored liquids in e-cigarettes has consequences similar to smoking tobacco, at least on epithelial cells that line the upper airway of the respiratory tract.

E-cigarettes have only been on the market in the United States since 2006, and usage has skyrocketed. Teens using e-cigarettes jumped 19 percent within a single year, and now more teens use them instead of traditional tobacco cigarettes.

The more than 7,000 flavors available in e-cigarettes are FDA approved, though that approval process was based on data created for oral consumption, not inhalation. However, the FDA will begin oversight of e-cigarettes in August.

For the study, a group of 13 non-smokers, 14 smokers, and 12 e-cigarette users was recruited to study what effects e-cigarettes have on genes that help our upper airways fight off potentially harmful pathogens. 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, the UNC team analyzed participant urine and blood samples to confirm nicotine levels and biomarkers related to tobacco exposure.

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

The epithelial layers of our nasal passages are very similar to the epithelial layers in our lungs. All epithelial cells 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. Specific genes in these cells must create proteins which orchestrate immune response. 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, the researchers found that smoking cigarettes decreased the gene expression of 53 genes important for the immune response of epithelial cells. Using e-cigarettes decreased the gene expression of 358 genes important for immune defense, including all 53 genes implicated in the smoking group.

“We compared these genes one by one, and we found that each gene common to both groups was suppressed more in the e-cigarette group,” said lead researcher Ilona Jaspers, professor of pediatrics, and microbiology and immunology at UNC. “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.

“I was really surprised by these results,” she said.

“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.”

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