In a Mouse Model, Exposure to E-Cigarette Vapor Did Not Induce Pneumonia

Exposure to nicotine-containing e-cigarette vapor had no effect on the ability of pneumococcal strain TIGR4 to infect a mouse model.This study was published in the December 2 issue of Applied and Environmental Microbiology.

Given the popularity of e-cigarettes and the rising number of deaths attributed to vaping, a group of researchers from the University of Louisiana at Lafayette began investigating whether e-cigarettes increase the risk of pneumonia.The report notes: "Pneumococcus is the most common cause of pneumonia in children under five, adults over 65, and immunocompromised individuals." Exposure to traditional cigarette smoke is a significant risk factor for pneumonia.

In this study, researchers compared the effects of exposure to nicotine-containing strawberry-flavored e-cigarette vapor, nicotine-free e-cigarette vapor, cigarette smoke, and no exposure to cigarette-related e-cigarettes on pneumococcus.

Compared to the control group, nicotine-containing e-cigarette vapor caused significant changes in pneumococcal gene expression, affecting 264 genes primarily involved in metabolism and stress response.Dr. Ritwij Kulkarni, an assistant professor of immunology at the University of Louisiana at Lafayette and the corresponding author, stated that nicotine-free e-cigarette vapor only altered the expression of 14 genes, and the changes were minor.The latter genes are involved in sugar transport and metabolism.In contrast, smoking altered the expression of 982 genes, which also primarily participate in metabolism and stress response.

Dr. Kulkarni said, "Interestingly, in the mouse infection model, both nicotine and nicotine-free e-cigarette vapors did not alter the ability of pneumococcus to cause lung infections." However, both nicotine-containing e-cigarette vapor and cigarette smoke moderately induced biofilm formation.

Dr. Kulkarni stated, "Our work is part of a series of observations from several research laboratories attempting to define what effects exposure to e-cigarette vapor may have on human health and to differentiate the impacts of flavoring chemicals and nicotine."

"Every day on my way to class, I see many students vaping," Dr. Kulkarni said. "We do not know what the vapor from e-cigarettes does to us or our microbiome.Since our lab focuses on respiratory bacterial infections, we decided to study pneumococcus, a deadly pathogen and a colonizer of the upper respiratory tract."

In the United States, pneumonia causes approximately 50,000 deaths each year, making it one of the leading causes of death from infectious diseases.The report notes: "Exposure to cigarette smoke is a key risk factor for pneumonia as it affects the physiological and immune responses of the respiratory tract and increases the virulence of pathogens residing in the nasopharyngeal mucosa."