Ultrastructural Changes in Autopsy Tissues of COVID-19 Patients.

Abstract

The COVID-19 pandemic resulted in substantial morbidity and mortality across the world. The prognosis was found to be poor in patients with co-morbidities such as diabetes, hypertension, interstitial lung disease, etc. Although biochemical studies were done in patient samples, no study has been reported from the Indian subcontinent about ultrastructural changes in the vital organs of COVID-19 patients.The present study was, therefore, conducted to understand the ultrastructural changes in the lung, liver, and brain of the deceased patients. The present study was conducted on samples obtained from reverse transcription-polymerase chain reaction(RT-PCR)-positive patients who were admitted to a tertiary care hospital in Western India. Core needle biopsies were done in eight fatal cases of COVID-19.The samples were taken from the lungs, liver, and brain and subjected to light microscopy, immunohistochemistry (IHC), and transmission electron microscopy (TEM). Clinical details and biochemical findings were also collected. Results:The study participants included seven males and one female. The presenting complaints included fever, breathlessness, and cough. Light microscopy revealed diffuse alveolar damage in the lungs. Further, a positive expression of SARS-CoV-2 nucleocapsid protein was observed in the pulmonary parenchyma of five patients. Also, the TEM microphotograph showed viral particles of size up to 80nm localized in alveolar epithelial cells. However, no viral particles were found in liver or brain samples.In the liver, macrovesicular steatosis and centrizonal congestion with loss of hepatocytes were observed in light microscopy. This is the first study in the Indian population showing thein-situ presence of viral particles in core biopsies from fatal cases of COVID-19. As evident from the results, histologyand ultrastructural changes in the lung correlated with the presence of viral particles. The study revealed a positive correlation between the damage in the lungs and the presence of viral particles.