Coronavirus and smoking
Scientists have demonstrated how smoking worsens the course of Covid-19
Denis Gordeev, Naked Science
This work will help researchers better understand the risks of coronavirus infection for smokers.
Researchers from the University of California at Los Angeles were able to demonstrate how smoking contributes to a more severe course of Covid-19. To do this, they used a model of respiratory tract tissue created from human stem cells.
An article about the work was published in Cell Stem Cell (Purkayastha et al., Direct exposure to SARS-CoV-2 and cigarette smoke increases infection severity and alters the stem cell-derived airway repair response).
Smoking is one of the most common causes of lung diseases, including cancer and chronic obstructive pulmonary disease. Most large-scale studies of patients with Covid-19 have shown that active smokers have a much higher risk of severe coronavirus infection and death from it. But the reasons for this are not entirely clear to specialists.
To clarify the issue, the authors of the new study decided to recreate the processes that occur when a smoker's respiratory tract is infected with the SARS-CoV-2 virus. "Our model reproduces the upper part of the respiratory tract, which is the first place where the virus enters," says study lead author Bridget Gomperts. "Mucus is produced here to trap viruses, bacteria and toxins."
The model tissues were grown from respiratory tract stem cells taken from the lungs of five young healthy non-smoking donors. To reproduce the negative effects of smoking, the researchers treated these cell cultures with cigarette smoke daily for four days. The time of one exposure session was three minutes.
The scientists then infected the tissues exposed to cigarette smoke with the live coronavirus SARS-CoV-2, along with identical cell cultures that were not negatively affected. In the models that were exposed to smoke, the researchers observed two to three times more infected cells.
Micrographs of models of respiratory tract tissue with cells infected with the SARS-CoV-2 virus (green); tissue exposed to cigarette smoke (right) had 2-3 times more infected cells than untreated tissue (left). A drawing from the press release Study reveals how smoking worsens COVID-19 infection in the airways.
The authors of the work determined that smoking led to a more severe course of Covid-19, at least in part, due to blocking interferons. These proteins play a crucial role in the early immune response of the body, forcing infected cells to produce antiviral proteins and "warning" uninfected cells about the appearance of a pathogen in the body.
The new work will help researchers better understand the risks of coronavirus infection for smokers. It can also provide useful information for the development of new therapeutic strategies that will reduce the likelihood of developing severe respiratory diseases in smokers.
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