Ever since vaping became a thing, scientists have been trying to figure out how it compares with smoking in terms of health effects. Companies that make e-cigarettes like to claim that vaping is harmless, or at least way safer than smoking… but what we’re finding is that it doesn’t cause the same problems that smoking does, it causes some problems of its own.
A paper published recently in the Journal of Clinical Investigation adds to this idea. They found that the presence of e-cigarette vapor altered lung immune cells in mice, making them more prone to infection. The researchers started by exposing the mice to traditional cigarette smoke, vapor from e-cigarettes both with and without nicotine, and then just also regular old air. The e-cigarette smoke didn’t trigger the kind of inflammation and structural changes to the lungs that can lead to conditions like emphysema—stuff that is seen with traditional cigarette smoke. So, yay. But, when they looked at the lung tissues under a microscope, they saw something strange was happening. Specifically, immune cells called macrophages were getting overly fatty.
These fats, called lipids, are important components of cells, and they play crucial roles in lung function and immunity. You see, your lungs are coated with a goo that helps trap foreign invaders while ensuring enough oxygen can get through. It works because it’s composed of a special mix of lipids and proteins. And macrophages are responsible for ensuring the goo has the right lipids in it. If macrophages are accumulating lipids inside of them, that suggests there’s something going wrong with the goo. And that could leave the lungs susceptible to infection.
The team ran another experiment. This time, they exposed the mice to e-cig vapor with nicotine, e-cig vapor without nicotine, or regular air for 3 months, and then gave them a lethal dose of flu virus. And it didn’t matter if the vapor had nicotine or not—the mice exposed to the vapors were significantly more likely to die. And when given sub-lethal doses, the mice exposed to e-cig vapors lost more weight, which the researchers interpreted as a weaker immune response.
They also found increases of inflammatory markers in the lungs, so their conclusion seemed clear — exposure to vaping impairs the lung’s immune system, even if it doesn’t contain nicotine. In mice, anyway. Though, if something similar happens in people, it could help explain the recent rush of pneumonia cases in people who vape.
You see, tests have found macrophages similarly laden with fats in the patient’s lungs. And that kind of connection between human cases and animal models is concerning. But, it doesn’t prove that vaping is directly responsible for people’s lung infections. Also, it’s not yet clear what it is in the vapor that causes these changes to lung immune cells. If we can pinpoint that, we might be able to make vaping products safer by switching up the ingredients. Still, studies seem to keep suggesting that vaping is harmful in its own unique way—which is why health regulatory agencies like the US FDA keep slamming companies for claiming their products are safe. And whether vaping is ultimately less risky than smoking, unfortunately, remains an open question.