A study published on the medRxiv website found significantly higher ACE2 gene expression in former smoker's lungs compared to non-smoker's lungs, which means ACE2 may be a potential invasive receptor of SARS-CoV-2 and smokers may be more susceptible to the novel coronavirus disease (COVID-19).
Considering that SARS-CoV-2 and SARS-nCov share the same receptor, the study analyzed five large-scale bulk transcriptomic datasets of normal lung tissue and two single-cell transcriptomic datasets to investigate the disparities related to race, age, gender and smoking status in ACE2 gene expression and its distribution among cell types, and they found ACE2 gene expression is significantly higher.
In addition, the ACE2 gene is expressed in specific cell types related to smoking history and location. Previously, a study published in the Chinese Medical Journal on February 28 also listed "history of smoking" as a factor that leads to the progression of COVID-19. Therefore, smoking history may provide valuable information in identifying susceptible populations and standardizing treatment regimen.
The risks of smoking amid COVID-19 crisis
Smokers are 14-times more at risk for severe coronavirus infection and 14 percent more likely to get pneumonia than those who have never smoked, according to a study published in Chinese Medical Journal last month.
Similar to the previous viral outbreaks of MERS or SARS, COVID-19 attacks the lungs and other parts of the respiratory system, and those who smoke tobacco may be especially threatened.
According to the previous researches, apart from the damage to the lungs and respiratory system, smoking could also stimulate the activity of chronic hepatitis C virus, and make it easier to develop severe hepatitis. Smoking also increases the risk of dying from cancer and other diseases in cancer patients and survivors.
Additionally, smokers are at greater risk for diseases that affect the heart and blood vessels (cardiovascular disease).
Wang Xiaojuan, director of the general department at Beijing Chaoyang Hospital, suggested in a previous interview that tobacco itself could do harm to the respiratory system, in addition to causing chronic bronchitis. And from a doctor's perspectives, all people should give up smoking, especially amid the COVID-19 crisis.