In the middle of a pandemic, stress can run really high and you might be tempted to light up a cigarette to decompress from the world around you. However, a CIRM-funded study revealed that you might want to think twice before lighting up.
It is already known that cigarette smoke is one of the most common causes of lung diseases, including lung cancer, but Dr. Brigitte Gomperts and Vaithilingaraja Arumugaswami at UCLA have pinpointed how smoking cigarettes may worsen infection by SARS-CoV-2, the virus that causes COVID-19, in the airways of the lungs.
The team used airway stem cells from the lungs of healthy non-smoking donors to create a tissue model that replicates the way that airways behave and function in humans. The researchers then exposed these newly created airways to cigarette smoke to mimic the effects of smoking.
Next, the team infected the airway tissue exposed with cigarette smoke with SARS-CoV-2 and also infected tissue not exposed to cigarette smoke. In the tissue model exposed to smoke, the researchers saw between two and three times more infected cells.
The UCLA team determined that smoking resulted in more severe SARS-CoV-2 infection. This was due to the smoke blocking the activity of immune system messenger proteins called interferons, which play an important role in the body’s early immune response. They trigger infected cells to produce proteins to attack the virus, summon additional support from the immune system, and alert uninfected cells to prepare to fight the virus. Cigarette smoke is known to reduce the interferon response in the airways.
In a UCLA news release, Dr. Gomperts explains the results with a simple analogy.
“If you think of the airways like the high walls that protect a castle, smoking cigarettes is like creating holes in these walls. Smoking reduces the natural defenses and that allows the virus to set in.”
The hope is that these findings will help researchers better understand COVID-19 risks for smokers and could inform the development of new therapeutic strategies to help reduce smokers’ chances of developing severe disease.
The full results to this study were published in Cell Stem Cell.