Pathological Analysis of the SARS-CoV-2 Virus
By: Sai Srihaas Potu
The devastating effects of the recent global pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) are paramount with new cases and deaths growing at an exponential rate. COVID-19 originated in the city of Wuhan, Hubei Province, Central China, and has spread quickly to 72 countries to date. At present, the newly identified SARS-CoV-2 has caused a large number of deaths with tens of thousands of confirmed cases worldwide, posing a serious threat to public health. However, there are no clinically approved vaccines or specific therapeutic drugs available for COVID-19. Intensive research on the newly emerged SARS-CoV-2 is urgently needed to elucidate the pathogenic mechanisms which can help lead to potential treatment strategies. Better understanding the pathological properties of COVID-19 will provide important insight into its origin, effects, and most importantly management.
Although there have been several studies describing clinical features of COVID-19 and characteristic radiographic findings, no pathological studies have been conducted based on autopsies or biopsies. Some of the reasons for the lack of autopsies and biopsies include the suddenness of the outbreak, the vast patient volume in hospitals, shortage of healthcare personnel, and the high rate of transmission, which makes invasive diagnostic procedures less of a clinical priority.
In light of this recent problem, researchers have collected biopsy samples from the lung, liver, and heart tissue of COVID-19 patients. After careful review scientists have been able to determine that the pathological features of COVID-19 greatly resemble those seen in SARS and Middle Eastern respiratory syndrome (MERS) coronavirus infection. In addition, the liver biopsy specimens of the patients with COVID-19 showed mild lobular and portal activity, which indicates that the SARS-CoV-2 virus can damage the lungs.
X-ray images showed a rapid progression of pneumonia and some differences between the left and right lung. The researchers found that even before patients developed symptoms, there had been early lung lesions. This means that even before the symptoms occur, changes are happening in the lung tissue of patients infected with COVID-19, which has a long incubation period of three to 14 days.
In addition, the liver tissue showed moderate microvascular steatosis and mild lobular activity, but there was no conclusive evidence to support SARS-CoV-2 infection or drug-induced liver injury as the cause. Subsequently, there were no obvious histological changes seen in heart tissue, suggesting that SARS-CoV-2 infection might not directly impair the heart. Recent research suggests that SARS-CoV-2 can cause heart attacks, but a pathological analysis of the virus says otherwise.
Considering the global threat to health caused by SARS-CoV-2, effective prevention, and treatment of COVID-19 pneumonia will be urgently needed. However, the development of drugs for pathogenic SARS-CoV-2 is still a major problem for humans, and there are currently no officially approved drugs to treat COVID-19. Although corticosteroid treatment is not routinely recommended to be used for SARS-CoV-2 pneumonia, recent pathological findings suggest that timely and appropriate use of corticosteroids together with ventilator support should be considered for severe patients.
SARS-CoV first appeared in 2002 and rapidly spread to 32 countries and regions, after which the world then experienced the outbreak of MERS-CoV in 2012. Recently, the newly emerged SARS-CoV-2 is undoubtedly a warning. With recent pathological studies, scientists have been able to determine SARS-CoV-2 can enter into lung cells by binding to ACE2. This creates a huge problem as ACE2 is also highly expressed in other tissues including the liver, intestines, and kidneys. Thus, these organs may also be damaged by SARS-CoV-2. Currently, SARS-CoV-2 has spread rapidly in multiple countries, caused severe illness, and sustained human-to-human transmission, making it a concerning and serious public-health threat. This could pose a huge problem for COVID-19 patients, doctors, and researchers. With the possibility that SARS-CoV-2 can attack the entire body, scientists need to develop a vaccine that can combat the growth and damage of the virus.
Although the management of severe and critical COVID-19 patients is important in reducing the mortality of the ongoing pandemic, the true key measures lie in prevention, monitoring, and timely intervention. To be fully prepared for this ongoing pandemic and an outbreak that might occur in the future, it is crucial to understand the pathogenesis of this disease. Clinical and pathological findings in this severe case of COVID-19 can not only help to identify a cause of death, but also provide new insights into the pathogenesis of SARS-CoV-2-related pneumonia, which might help physicians to formulate a timely therapeutic strategy for similar severe patients and reduce mortality.
1. Huang C, Wang Y, Li X. Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China. Lancet. 2020.
2. Song Z, Xu Y, Bao L, Zhang L, Yu P, Qu Y. From SARS to MERS, thrusting coronaviruses into the spotlight. Viruses. 2019.
3. Zhe Xu, Lei Shi, Yijin Wang, Jiyuan Zhang, Lei Huang, Chao Zhang. Pathological findings of COVID-19 associated with acute respiratory distress syndrome. Lancet Respiratory Medicine. 2020.