Smoking causes inflammation

The cancer-causing effects of smoking have been known for decades, but how smoking is related to immune changes had been previously unclear. 

In a report published in the Journal of Leukocyte Biology, it showed that nicotine activates certain white blood cells, called neutrophils - type of white blood cells in most mammals - which in turn releases molecules that lead to increased inflammation.

"Our study reveals an explanation how nicotine contributes to induction of inflammation and in doing so shows new possibilities for future therapies to treat tobacco-related diseases which each year lead to premature deaths of several million people worldwide," said Constantin Urban from the Umea University in Sweden.

The findings have important implications including that alternative forms of nicotine inhalation, such as vaping that lacks other chemicals from cigarette smoke, may nonetheless still have detrimental immunological effects, the researcher said.

To make this discovery, the researchers stimulated isolated neutrophils from humans and mice with nicotine and could measure a dose-dependent release of inflammatory molecules. 

By using pharmacological small molecule inhibitors as well as neutrophils from genetically modified mouse strains, the team could identify essential receptor and signaling pathways involved in the nicotine-mediated activation of neutrophils.