Infection with the coronavirus, like severe flu, can severely damage the airways and lead to fatal lung failure. So far, however, it is hardly known which molecular changes “SARS-CoV-2” triggers in the lung tissue of patients and how they differ from the damage caused by the influenza virus. In order to better understand the disease processes, an international research team from Germany, the USA, Belgium and Switzerland has now examined the lungs of those who died from “Covid 19” and compared them with those of those who died from flu (influenza).
“The study improves our understanding of why lung function in SARS-CoV-2-infected people with severe illnesses is so severely impaired,” emphasizes Professor Danny Jonigk, lung specialist at the Hannover Medical School. The results of the investigation entitled “Pulmonary Vascular Endothelialitis, Thrombosis and Angiogenesis in COVID-19” have now been published by the renowned journal “New England Journal of Medicine”.
Microthrombi block the finest vessels
“For the first time, we examined the tissue samples synergistically with a very wide range of methods from micro-computed tomography, 3D electron microscopes and various molecular biological methods in order to track down the pathways of SARS-CoV-2,” says Professor Jonigk. The scientists were initially able to demonstrate the already known acute damage pattern in the lungs of “Covid-19” patients, the so-called diffuse alveolar damage.
This occurs when the walls of the alveoli become inflamed, covered by protein deposits and thus make it difficult to supply oxygen to the blood. “We also found a massive number of blood clots in all sections of the blood vessels in the lungs, but especially in the finest vessels, the capillaries,” says the pathologist. “These microthrombi clog the fine pulmonary vessels and thus additionally increase the patient’s shortness of breath.” Although the phenomenon also exists in severely damaged lungs after influenza infections, the number of these small blockages is significantly lower in the case of flu deaths.
Another finding that is particularly striking is the fact that physicians are usually only familiar with from tumor diseases, autoimmune diseases or scarring processes: “SARS-CoV-2” apparently triggers a special form of new vessel formation in the lungs. “This so-called intususceptive neoangiogenesis has not yet been described in the context of diffuse alveolar damage and distinguishes ‘Covid-19’ fundamentally from comparable severe lung infections caused by influenza viruses,” emphasizes Professor Jonigk and summarizes: “The three changes within our study that were described in detail for the first time The lungs with ‘SARS-CoV-2’ infections are the massive damage to the blood vessels, the excessive blood clotting with constipation of the finest lung vessels and the formation of new blood vessels, which is characteristic of COVID-19. “
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