Scientists have analysed organ samples from dead Covid-19 patients and found extensive lung damage generally caused by the persistence of odd “fused cells,” an advance which sheds more light on the progression of the disease.
The researchers, including those from King’s College London in the United Kingdom, examined lung, heart, liver, and kidney samples of 41 patients who died of Covid-19 to inspect the behaviour of the novel coronavirus SARS-CoV-2.
In the study, published in the publication eBioMedicine, they revealed the unique characteristics of the virus that may provide an explanation for why some patients experience disease symptoms for months — referred to as ‘long Covid’ — with a feeling of fatigue and lack of breath.
The findings show extensive lung damage generally, with patients experiencing profound disruption of the normal lung constitution and the transformation of respiratory tissue into fibrotic fabric.
According to the scientists, almost 90 per cent of the patients showed extra characteristics that were relatively unique to Covid-19 in comparison to other forms of pneumonia.
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They said there was once extensive blood clotting of the lung arteries and veins, and several lung cells were abnormally large with many nuclei, resulting from the fusion of different cells into unmarried large cells. The researchers famous that this formation of fused cells — syncytia — is because of the viral spike protein, which the virus uses to go into the cell. When the protein is present on the surface of cells infected by the Covid-19 virus, the study famous that it stimulates their fusion with other normal lung cells, which could be a cause for inflammation and thrombosis.
The research also showed the long-term persistence of the viral genome in respiratory cells and in cells lining the blood vessels, at the side of the infected cell syncytia. According to the researchers, the presence of these infected cells can cause the major structural changes observed in lungs, which can persist for several weeks or months, and could eventually provide an explanation for ‘long Covid’.
“The findings indicate that Covid-19 isn’t simply a disease caused by the death of virus-infected cells but is likely the consequence of these odd cells persisting for long periods within the lungs,” said Mauro Giacca, a co-author of the study from King’s College London.