HKU research team reveals how the novel coronavirus (HCoV-EMC) causes disease in human respiratory tract and the potential options for clinical treatment. By using human lung tissues maintained in culture, the researchers discover that the novel coronavirus is as virulent or more virulent that SARS coronavirus in causing lung damage. This research has recently been published in the international virology journal, Journal of Virology.
Researchers at the Centre of Influenza Research of the School of Public Health, the Department of Pathology and the State Key Laboratory of Emerging Infectious Diseases of The University of Hong Kong Li Ka Shing Faculty of Medicine, lead the research. One of the key members of the team, Dr. Michael Chan Chi-wai, Assistant Professor of the School of Public Health says, “How HCoV-EMC causes severe disease and death in humans is still unknown." We have made use of our human lung ex vivo explant culture system to show for the first time how the novel coronavirus cause human disease in lung and how it may spread to other organs. Our team also finds that interferon treatment can suppress the virus infection in the lung. It brings insight to potential treatment strategies for the novel coronavirus.”
The researchers use human lung tissues maintained in culture to compare infection with the novel coronavirus (HCoV-EMC), SARS coronavirus (SARS-CoV) and the common cold virus 229E. They find that the novel coronavirus infects and replicates in human alveolar type I and type II epithelial cells in the lung and it multiplies even faster than the SARS coronavirus causing severe lung injury.
Type I alveolar epithelial cells are crucial for oxygen exchange in the lungs and damage to these cells leads to difficulty in breathing. Type II alveolar epithelial cells are the key cell for regeneration and repair of damaged lung tissues and damage to these cells will prevent repair processes that allow the lung to recover from injury or infection.
Taken together, this explains the severe pneumonia caused by this virus and the severity of disease. It further shows that the novel HCoV-EMV is as virulent or more virulent than SARS-CoV in causing lung damage. They also point out that the virus infects the cells lining the blood vessels of the lung (endothelial cells), suggesting that the virus may spread through the blood stream to affect organs distant from the respiratory tract.
To explore the possible treatment strategies, the research also addresses the pathogenesis of the novel coronavirus. The result demonstrates that the novel coronavirus avoids activating the human lung interferon responses, which are the first-line host defense system to defend against viral infection, and allows the virus to continue to replicate and cause damage to the lung. On the other hand, the virus infection in the lung can be suppressed by interferon treatment, suggesting that this is a treatment option that may be beneficial in treating humans with novel coronavirus infected disease.
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