Study: E-cigarettes alter the inflammatory state of the brain, heart, lungs and colon

Researchers at the University of California, San Diego School of Medicine report that daily use of pod-based e-cigarettes alters the inflammatory state of multiple organ systems including the brain, heart, lungs and colon. The effect also varies depending on the taste of the e-cigarette and can affect the organ’s response to infection, such as SARS-CoV-2.

Published in the journal eLife on April 12, 2022, the study was the first to evaluate JUUL devices and their flavorings in a multi-organ manner.

“These pod-based e-cigarettes have only become popular in the last five years or so, so we know very little about their long-term health effects,” said Laura Crotty Alexander, MD, MD, senior study author. Director of the Pulmonary Intensive Care Unit for Medical and Veterans Affairs San Diego Health Care System at the University of California, San Diego School of Medicine.

More than 12 million adults in the United States currently use e-cigarettes, with 18-24 years old having the highest rate of use. Despite the popularity of e-cigarettes, research on e-cigarettes has largely been limited to research on short-term use, old devices (such as e-cigarette pens or box modules), and e-cigarette oils with significantly lower nicotine concentrations than modern rechargeable cartridge systems.

Crotty Alexander’s team focuses on JUUL, the most well-known e-cigarette brand today, and its most popular flavors: mint and mango. To simulate chronic e-cigarette use, young adult mice are exposed to flavored JUUL aerosols 3 times a day for three months. The researchers then looked throughout the body for signs of inflammation.

The authors saw the most notable effects in the brain, in which several inflammatory markers were elevated. Other changes in neuroinflammation gene expression have been found in the accumbens, a brain region that is critical for motivation and reward processing.

They say the findings raise significant concerns because neuroinflammation in the region is linked to anxiety, depression and addictive behaviors, which could further exacerbate substance use and addiction.

“Many JUUL users are teenagers or young adults whose brains are still developing, so considering how this affects their mental health and behavior, it’s very scary to understand what might be going on in their brains,” Crotty Alexander said

Expression of inflammatory genes in the colon also increases, especially after a month of exposure to e-cigarettes, which may increase the risk of gastrointestinal diseases. In contrast, the heart shows a decrease in levels of inflammatory markers. This immunosuppressive state may make heart tissue more susceptible to infection, the authors said.

Although the lungs show no signs of inflammation at the tissue level, many gene expression changes have been observed in the samples, and further research is needed on the long-term effects of pod-based e-cigarettes on lung health.

The researchers also found that the inflammatory response of each organ varied depending on the FLAVOR OF JUUL used. For example, the hearts of mice inhaling peppermint aerosol were much more sensitive to the effects of bacterial pneumonia than mice that inhaled mango aerosol.

“It was a real surprise for us,” Croti Alexander said. “This shows us that flavor chemicals themselves are also causing pathological changes.” If people who regularly use peppermint-flavored JUUL e-cigarettes become infected with COVID-19, their bodies may respond differently to the infection. ”

Each organ has its own fine-tuned immune environment, so disrupting this balance through the use of e-cigarettes can lead to many long-term health effects, the authors write.

“It’s clear that every e-cigarette device and flavor must be studied to determine how it affects whole-body health,” Croti Alexander said.