Cardiovascular problems are a threat in COVID-19. The disproportionate effect of COVID-19 on patients with other cardiovascular issues are not fully understood.
COVID-19 infects using the "ACE2" receptor. This receptor if found in many organs including lung, heart and kidney. ACE2 receptors are also seen in endothelial cells. Endothelial cells line the inner surface of blood vessels. The authors demonstrate how these cells are involved in different organs of COVID-19 patients.
Patient 1 was a male kidney transplant recipient. He was aged 71 years, with coronary artery disease and high blood pressure. The patient's condition worsened with COVID-19. He required a ventilator to breathe. The patient died on day 8 after multiple organ failure. After death, the transplanted kidney was observed. An electron microscope showed viral inclusion structures in endothelial cells.
Patient 2 was a woman, aged 58 years. She had diabetes, high blood pressure, and obesity. She developed respiratory failure due to COVID-19. She later developed multi-organ failure. Her damaged kidney meant that she needed blood filtration. On day 16, a lack of blood supply meant a dead part of her small intestine had to be removed. She died due to a heart attack. Analysis after hear death showed immune response in the endothelium of her lung, heart, kidney, and liver. Additionally, there was death of liver cells. The authors found evidence of a heart attack. The small intestine had immune responses in the endothelium of some vessels..
Patient 3 was a man, aged 69 years. He had high blood pressure and developed respiratory failure due to COVID-19. He required a ventilation. He had a circulatory failure with a lack of blood supply in the small intestine. Part of the small intestine was removed. The patient survived. Analysis of the small intestine showed immune responses in the endothelium of some vessels.
The authors found evidence of direct viral infection in the endothelial cells. Though the virus uses ACE2 receptors in the lung cells, ACE2 receptor is also seen in endothelial cells in various organs.
These finding show viral elements in endothelial cells. These finding suggest that COVID-19 triggers an immune response in endothelial cells. Endothelial cells are present in several organs. This could explain why there is poor micro circulation in certain parts of the body of COVID-19 patients. This hypothesis could suggest therapies to stabilize the endothelium while dealing with viral replication. The viral replication can be targeted with various drugs including ACE inhibitors. This strategy could be especially useful for patients with poor functioning endothelium. This poor function can be caused by smoking, high blood pressure, diabetes, obesity another cardiovascular disease.