Potential use of the S-protein-Angiotensin converting enzyme 2 binding pathway in the treatment of coronavirus disease 2019.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen that causes coronavirus disease 2019 (COVID-19), infects humans through a strong interaction between the viral spike protein (S-protein) and angiotensin converting enzyme 2 (ACE2) receptors on the cell surface. The infection of host lung cells by SARS-CoV-2 leads to clinical symptoms in patients. However, ACE2 expression is not restricted to the lungs; altered receptors have been found in the nasal and oral mucosa, vessel, brain, pancreas, gastrointestinal tract, kidney, and heart. The future of COVID-19 is uncertain, however, new viral variants are likely to emerge. The SARS-CoV-2 Omicron variant has a total of 50 gene mutations compared with the original virus; 15 of which occur in the receptor binding domain (RBD). The RBD of the viral S-protein binds to the human ACE2 receptor for viral entry. Mutations of the ACE2-RBD interface enhance tight binding by increasing hydrogen bond interactions and expanding the accessible surface area. Extracorporeal membrane oxygenation, hyperbaric oxygen, and aggressive dialysis for the treatment of COVID-19 have shown various degrees of clinical success. The use of decoy receptors based on the ACE2 receptor as a broadly potent neutralizer of SARS-CoV-2 variants has potential as a therapeutic mechanism. Drugs such as 3E8 could block binding of the S1-subunit to ACE2 and restrict the infection of ACE2-expressing cells by a variety of coronaviruses. Here, we discuss the development of ACE2-targeted strategies for the treatment and prevention of COVID-19.

How Should Anesthesiologists Face Coronavirus Disease 2019?

Coronavirus disease 2019 (COVID-19) is a highly contagious disease. Most infected patients manifest mild flu-like symptoms, but in some cases, the patients rapidly develop severe lung infections and pneumonia. It is estimated that about 15-20% of patients with COVID-19 develop hypoxemia and require some form of oxygen therapy and ventilation support. Further, exacerbation of the disease usually requires an emergency tracheal intubation, where the patients are more prone to coughing and aerosol diffusion, placing the anesthesiologist at an extremely high risk of infection. In this review, after a brief introduction to the epidemiology and pathogenesis of the COVID-19, we describe various recommendations that the anesthesiologists should employ to avoid the chances of infection during the management of severely ill patients. We describe key steps such as not removing the patient's mask prematurely and using sedatives, analgesics, and muscle relaxants for rapid and orderly intubation. The use of spinal cord and regional nerve block anesthesia should also be promoted to avoid general anesthesia. Since the patients with COVID-19 may also have disorders related to other parts of the body (other than lungs), short-acting drugs are recommended to actively maintain the perfusion pressure of the peripheral and important organs without metabolism of the drugs by the liver and kidney. Multimodal analgesia is advocated, and non-steroidal anti-inflammatory analgesic drugs can be used appropriately. In this review, we also discuss key studies and experiences of anesthesiologists from China, highlights research findings, and inform on the proper management of patients with perspective on anesthesiologists.