New research from the UNC School of Medicine has found users of nicotine-salt-containing pod and disposable e-cigarettes display unique markers of immune suppression not seen in users of other kinds of e-cigarettes. The study indicates the long-term health implications of this kind of altered immune system response are unknown.

The new research, funded by the National Institutes of Health, set out to explore the health impacts of different kinds of e-cigarette devices. In particular, this study focused on what are referred to as “fourth-generation” vaping devices. These are modern devices that use nicotine salts, such as pod-based e-cigarettes and Juul products, unlike “third-generation” devices like box mods and vape pens.

The researchers gathered sputum samples from four different groups: non-smokers, tobacco smokers, third-generation e-cigarette users, and fourth-generation e-cigarette users. A number of different inflammatory biomarkers were measured in the sputum samples.

The main finding was an unusually high volume of bronchial epithelial cells in the sputum of fourth-gen e-cig users. These cells are not normally found in sputum samples and are often markers of airway injury.

Another significant finding were low levels of a broad array of immune cells in fourth-gen users, including CRP, IFN-g, MCP-1, uteroglobin, MMP-2, and VEGF. These levels of immune biomarkers were notably lower than what was seen in third-gen e-cig users. The researchers indicate this could mean immune systems in fourth-gen e-cig users are abnormally suppressed.

“[A] key finding of the study was that, when examining the mixture of immune markers overall rather than one by one, fourth-generation e-cigarette users had the most distinguishable changes out of all of the groups, indicating a shift away from immune homeostasis,” said Elise Hickman, lead author on the study.

It’s important to note the study cannot directly link these immune differences with particular health outcomes. The researchers are clear these findings do not associate fourth-generation e-cigarette use with diseases such as cancer or emphysema.

Instead, the researchers suggest the findings indicate these specific kinds of e-cigarette devices may lead to novel impacts on the immune system. The impacts are not seen with other kinds of electronic cigarette devices and the long-term effects on health are unknown.

“It’s impossible to know if vaping decreases cancer risk or many other long-term conditions,” explains Ilona Jaspers, another researcher working on the project. “It took 60 years of research to show that smoking causes cancer. Still, the research from our lab and many others has shown many of the same acute biological effects in the airways that we have documented in smokers. And we’ve seen some changes to cells and immune defenses in people who vape that, frankly, we’ve never seen before, which is very concerning.”

While this is the first study to zoom in on immune biomarker differences between users of different kinds of e-cigarettes, other recent research has pointed to some possible dangers from pod-based e-cig devices. An animal study earlier this year from the University of California San Diego School of Medicine found nicotine-salt e-cigarettes generated inflammatory markers in a wide variety of organs.

Jaspers said it will be important for e-cigarette researchers to consider the impacts of different devices in all kinds of study moving forward. Exactly what the long-term health impacts of vaping are is still unclear but what is increasingly clear is that not all electronic cigarette devices are equal in how they affect the human body.

The new study was published in the American Journal of Respiratory and Critical Care Medicine.

Source: UNC School of Medicine