E-cigarettes weaken immune system
E-cigarettes are not as harmless as they look. Researchers suggest that e-cigarettes weaken the immune system while strengthening bacteria in the body.
The University of California, San Diego School of Medicine and Veterans Affairs San Diego Healthcare System study is published January 25 by the Journal of Molecular Medicine.
“This study [on mice] shows that e-cigarette vapor is not benign — at high doses it can directly kill lung cells, which is frightening,” said senior author Laura E. Crotty Alexander, MD, staff physician at the Veterans Affairs San Diego Healthcare System and assistant clinical professor at UC San Diego School of Medicine. “We already knew that inhaling heated chemicals, including the e-liquid ingredients nicotine and propylene glycol, couldn’t possibly be good for you. This work confirms that inhalation of e-cigarette vapor daily leads to changes in the inflammatory milieu inside the airways.”
Inflammatory markers — signs of full-body inflammation — in the airways and blood of mice that inhaled e-cigarette vapors for one hour a day, five days a week, for four weeks were elevated by 10 percent compared to unexposed mice.
Conversely, bacterial pathogens exposed to e-cigarette vapor benefited. Specifically, Staphylococcus aureus bacteria were better able to form biofilms, adhere to and invade airway cells and resist human antimicrobial peptides after exposure to e-cigarette vapor.
E-cigarette vapor extract-exposed bacteria were also more virulent in a mouse model of pneumonia. All mice infected with normal methicillin-resistant S. aureus (MRSA), an antibiotic-resistant “superbug,” survived. Meanwhile, 25 percent of mice infected with MRSA pre-exposed to e-cigarette vapor died.
The results were consistent with e-liquids from seven different manufacturers, demonstrating that the findings are not limited to one formula or brand.
