Researchers explore pathway between nicotine use and inflammation

UMEA, Sweden - As if there aren't enough reasons to kick the nicotine habit already, researchers from Umeå University in collaboration with U.S. researchers found a new link between nicotine and inflammation.

"This particular finding explains the missing piece of the puzzle of tobacco usage and inflammation," stated Ava Hosseinzadeh, who worked on this project during her doctoral dissertation. "This novel finding opens new avenues to understand the consequences of tobacco usage for human health and should be seen as one more convincing argument to quit nicotine usage in any form."

In a recently published article in the Journal of Leukocyte Biology, researchers at the Laboratory for Molecular Infection Medicine Sweden at Umeå University found that nicotine activates neutrophils in an undesirable fashion.

Neutrophils are the most abundant type of white blood cells that circulate in the blood stream ready to attack invading microbes with an arsenal of antimicrobial compounds. Neutrophils are essential to prevent infection by engulfing invading microbes, or by releasing reactive oxygen species as well as DNA fibres from their own nuclei, termed neutrophil extracellular traps (NETs). NET release is a mixed blessing. Loaded with antimicrobial enzymes and pro-inflammatory molecules NETs are harmful to invading microbes, however, they can also potently harm the host's own tissue, if not controlled in the right manner.

In recent years, NETs have been attributed to be mediators of tissue damage in several inflammatory diseases, such as small vessel vasculitis, arthritis and cancer.

For the first time, Hosseinzadeh and colleagues at MIMS show that nicotine triggers NET release. The signal to trigger NETs is mediated by a specific acetylcholine receptor found on neutrophils and further signalled into the cell via a protein kinase known as Akt.

"The next evident step is to demonstrate the NET-inducing capacity of nicotine in animal models and human samples," commented Constantin Urban, associate professor and project leader at Umeå University. "Such 'in vivo' studies will enable us to attract new funders and potentially interest of the pharma industry. Our finding could hopefully lead to novel anti-inflammatory therapies of tobacco usage related diseases."