0126 GMT January 18, 2020
"Our data show that cells in humans are affected by thirdhand smoke," said Prue Talbot, a professor in the Department of Molecular, Cell and Systems Biology, who led the research. "The health effects of THS, have been studied in cultured cells and animal models, but this is the first study to show a direct effect of thirdhand smoke on gene expression in humans, medicalxpress.com wrote."
Study results appear in JAMA Network Open.
Thirdhand smoke, or THS, results when exhaled smoke and smoke emanating from the tip of burning cigarettes settles on surfaces such as clothing, hair, furniture, and cars. Not strictly smoke, THS refers to the residues left behind by smoking.
"THS can resurface into the atmosphere and can be inhaled unwillingly by nonsmokers," said Giovanna Pozuelos, the first author of the research paper and a graduate student in Talbot's lab. "It has not been widely studied, which may explain why no regulations are in place to protect nonsmokers from it."
The researchers obtained nasal scrapes from four healthy nonsmokers who had been exposed to THS for three hours in a laboratory setting at UC San Francisco. The UCR researchers then worked to get good quality RNA from the scrapes — necessary to examine gene expression changes. RNA sequencing identified genes that were over- or under-expressed. They found 382 genes were significantly over-expressed; seven other genes were under-expressed. They then identified pathways affected by these genes.