Добавки вейпов разрушают защитный слой легких: результаты исследования Университета Канзаса

LAWRENCE — A new study from the University of Kansas shows that additives common to commercially available vaping devices, vitamin E and CBD, soften a vital lung surfactant at high enough concentrations, at least in a simplified lab model. The research appears in the peer-reviewed journal Langmuir. Co-author Prajnaparamita Dhar, professor of chemical & petroleum engineering at KU, said the findings should give pause to those who vape or are considering vaping. “Not enough studies have been done, and so let’s wait before we say, ‘Oh, it's better than smoking, so we are fine,’” she said. “Especially if we see an increase in use among adolescents, where the lung is a developing organ — we may want to be a little bit more vigilant as parents.” Human lungs contain millions of tiny air sacs called alveoli that open and close while we breathe. The alveoli have a flexible coating called “lung surfactant” that aids this expansion and contraction. “It’s a soap-like material deep in your lung,” Dhar said. “It outlines basically every one of your alveoli, and it helps us to breathe by preventing collapse of the alveoli when you breathe out. It maintains that pressure difference across two alveoli so that the next time you breathe in, it's like blowing up a balloon. What we really want to highlight is that there are mechanical properties that are being compromised with these vapes.” Dhar and her research team set up a laboratory experiment using a simplified lipid film containing dipalmitoylphosphatidylcholine (DPPC), the major lipid ingredient of lung surfactant, making up more than half of the total lipid weight. Next, they added vitamin E or CBD at different concentrations. “What we are trying to mimic is the breathing cycle, not the total number of alveoli,” Dhar said. “In our model, what we’re trying to mimic is the lungs’ compressing and expanding during the breathing cycle. So, we’re taking a thin film and modeling that expansion-contraction process. Those frequencies at which we are compressing or deforming the film are the same as the frequency of breathing.” Dhar’s collaborators on the project were graduate and undergraduate researchers from her group in the KU School of Engineering. “Much of this work was performed in the lab (with) my graduate student, Estephanie Escobar, a Fulbright scholar from Brazil, who just graduated and returned to her country,” said Dhar, who also serves as associate director at the Center for Teaching Excellence. “She helped me mentor two female undergraduate students who have since gone on to graduate school.” Dhar and Escobar’s collaborators were Emmanuelle Ong and Madelyn Leslie Atkins. The team measured the film's “rheology” — or how it behaves mechanically under the rapid, repeated deformation that mimics a lung during breathing. Then, using fluorescence microscopy, they could observe the lipids reorganize as the film expanded and contracted. The team discovered that vitamin E had more of a disruptive effect on the lung surfactant than CBD, and both had greater effects at higher concentrations. “We’re proposing vitamin E’s chemical composition leads to differences in the structure,” Dhar said. “It’s larger, more hydrophobic, so it can insert into that film more. The cannabidiol is smaller, so then it does not disrupt the film as much, because it’s a smaller molecule. That’s what we’re hypothesizing at this point.” Changes to lung-surfactant potentially could hurt lung function. “The primary concern is if it is too soft, it is not going to maintain its stability when you compress it,” Dhar said. “If it’s too soft, it’ll just break. It will not be able to resist that deformation.” The KU researcher cautioned that while the model used in the study contained the key lipid present in the human lung, it didn’t include proteins. “The major lipid that we have in the lung is at least 50%,” Dhar said. “Then during the breathing cycle, it is actually going through this interface, which is that water-air barrier that goes through refinement, and 90% is the lipid that we are studying. But certainly, the proteins also will play a role. We don’t know for sure what.” Dhar said she suspects the proteins in the lung could play a role in holding material close to the interface, changing how the film bounces back once force is taken away. “We would like to study that,” she said. “We would like some funding for it. When we think of engineers, we are not thinking of them studying these kinds of things. But I strongly believe that the lung is a perfect route for us to study environmental pollutants and other things that are going into our lung, and vaping is one of them.” Dhar said that as a public health issue, vaping deserves attention from researchers, regulators, consumers, teachers and parents. “Especially if we see an increase in use among adolescents, where the lung is a developing organ at that point,” she said. “One of the issues that motivates me to study this even more is that you will notice the number of vaping shops around us has increased. And vaping has been something that we are seeing even in our middle school students. That is actually an issue if you talk to middle school teachers, and they are trying to control it.”