E-cigarette users may incur small airway–centred fibrosis, including constrictive bronchiolitis, found a four-patient study published in the New England Journal of Medicine Evidence. The damage may be partially reversed after quitting, say researchers.
In the first study to microscopically evaluate the pulmonary tissue of e-cigarette users for chronic disease, in a small sample of patients, the team from Massachusetts General Hospital (MGH) found fibrosis and damage similar to the chemical inhalation damage to the lungs typically seen in soldiers returning from overseas conflicts who had inhaled mustard or similar types of noxious gases, reports MedicalXpress.
“All four individuals we studied had injury localised to the same anatomic location within the lung, manifesting as small airway-centred fibrosis with constrictive bronchiolitis, which was attributed to vaping after thorough clinical evaluations excluded other possible causes,” said lead author Dr Lida Hariri, a pathologist and physician investigator at MGH.
“We also observed that when patients ceased vaping, they had a partial reversal of the condition over one to four years, though not complete due to residual scarring in the lung tissue.”
The US has seen a huge increase in vaping, particularly among young adults and adolescents, with studies showing about 9% of the population and nearly 28% of high school students are e-cigarette users. Unlike cigarette smoking, however, the long-term health risks of chronic vaping are largely unknown.
To determine the underlying pathophysiology of vaping-related symptoms, the MGH team examined a cohort of four patients, each with a three-to-eight-year history of e-cigarette use and chronic lung disease. All patients underwent detailed clinical evaluation, including pulmonary function tests, high-resolution chest imaging, and surgical lung biopsy. Constrictive bronchiolitis, or narrowing of the small airways due to fibrosis within the bronchiolar wall, was observed in each patient.
So was significant over-expression of MUC5AC, a gel-forming protein in the mucus layer of the airway that has been seen in airway cell and sputum samples of vapers. In addition, three of the four patients had evidence of mild emphysema consistent with their former combustible cigarette smoking history, though researchers concluded this was distinct from the findings of constrictive bronchiolitis seen in the patient cohort.
Because the same type of lung damage was observed in all patients, as well as partial improvement in symptoms after e-cigarette usage was stopped, researchers concluded that vaping was the most likely cause after thorough evaluation and exclusion of other possible causes.
“Our investigation shows that chronic pathological abnormalities can occur in vaping exposure,” said senior author Dr David Christiani, a physician investigator at Mass General Research Institute.
“Physicians need to be informed by scientific evidence when advising patients about the potential harm of long-term vaping, and this work adds to a growing body of toxicological evidence that nicotine vaping exposures can harm the lungs.”
A hopeful sign from the study was that three of the four patients showed improvements in their pulmonary function tests and high-resolution computed tomography (HRCT) chest imaging after they ceased vaping.
“While there is growing evidence to show that vaping is a risky behaviour with potential long-term health consequences for users,” said Hariri, “our research also suggests that quitting can be beneficial and help to reverse some of the disease.”
Study details
E-Cigarette Use, Small Airway Fibrosis, and Constrictive Bronchiolitis
Lida Hariri, Bess Flashner, David Kanarek, Walter O’Donnell, Alyssa Soskis, David Ziehr, Angela Frank, Sreyankar Nandy, Sarita Berigei, Amita Sharma, Douglas Mathisen, Colleen Keyes, Michael Lanuti, Ashok Muniappan, Jo-Anne O’Malley Shepard, Mari Mino-Kenudson, Amy Ly, Yin Hung, Flavia Castelino, Harald Ott, Benjamin Medoff, David Christiani.
Published in the New England Journal of Medicine Evidence on 13 May 2022
Abstract
Background
Vaping, including the use of electronic cigarettes (e-cigarettes), has become increasingly prevalent, yet the associated long-term health risks are largely unknown. Given the prevalence of use, particularly among adolescents early in their lifespan, it is vital to understand the potential chronic pathologic sequelae of vaping.
Methods
We present the cases of four patients with chronic lung disease associated with e-cigarette use characterised by clinical evaluation, with pulmonary function tests (PFTs), chest high-resolution computed tomography (HRCT), endobronchial optical coherence tomography (EB-OCT) imaging, and histopathologic assessment.
Results
Each patient presented with shortness of breath and chest pain in association with a 3- to 8-year history of e-cigarette use, with mild progressive airway obstruction on PFTs and/or chest HRCT findings demonstrating evidence of air trapping and bronchial wall thickening. EB-OCT imaging performed in two patients showed small airway–centred fibrosis with bronchiolar narrowing and lumen irregularities. The predominant histopathologic feature on surgical lung biopsy was small airway–centred fibrosis, including constrictive bronchiolitis and MUC5AC over-expression in all patients. Patients who ceased vaping had a partial, but not complete, reversal of disease over 1 to 4 years.
Conclusions
After thorough evaluation for other potential etiologies, vaping was considered to be the most likely common causal etiology for all patients due to the temporal association of symptomatic chronic lung disease with e-cigarette use and partial improvement in symptoms after e-cigarette cessation. In this series, we associate the histopathologic pattern of small airway–centred fibrosis, including constrictive bronchiolitis, with vaping, potentially defining a clinical and pathologic entity associated with e-cigarette use.
MedicalXpress article – Study finds damage in the lungs of chronic e-cigarette users (Open access)
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