Two studies published in nature denied the efficacy of chloroquine and hydroxychloroquine

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 Two studies published in nature denied the efficacy of chloroquine and hydroxychloroquine


Professor Markus Hoffmanns team found that there are two pH dependent and pH independent pathways for the infection of new coronavirus. The infection of novel coronavirus pneumonia in human respiratory epithelial cells is caused by TMPRSS2 protease expressed in human cells, which activates the spike protein of new crown virus, which leads to virus invasion. In this process, the effect of TMPRSS2 protease was not significantly affected by pH change, which was a pH independent infection pathway.

However, in Vero cells used in previous experiments, the catl protease expressed by the cells activated the spike protein of new coronavirus, and this pathway was obviously affected by the change of pH. The researchers found that chloroquine and hydroxychloroquine can increase the pH value in human body, thus inhibiting the function of catl protease, so that the new coronavirus can not infect Vero cells. This is also the reason why chloroquine and hydroxychloroquine show antiviral activity in Vero cells.

In a controlled trial, the researchers compared the resistance and toxicity of chloroquine in three different cells: normal Vero cells, Calu-3 cells (human lung cells), and modified Vero cells that express TMPRSS2. The results showed that chloroquine could not inhibit the infection of new coronavirus in the last two kinds of cells expressing TMPRSS2, which confirmed the previous findings of researchers and the results of clinical trials.

Another group of French scientists did a similar experiment. Vero cells and reconstituted human respiratory epithelial cells were compared. The results showed that hydroxychloroquine could only reflect the resistance and toxicity in Vero cells, but could not inhibit the infection of new coronavirus on the reconstructed human respiratory epithelial cells.

In addition, the French team conducted more detailed animal experiments. They used cynomolgus monkeys as research animals, and designed five different drug use programs to explore the effect of treatment and prevention of new coronavirus infection. The results showed that hydroxychloroquine could not reduce the viral load in experimental animals. At the same time, hydroxychloroquine cant prevent infection. The novel coronavirus pneumonia was not treated with hydroxychloroquine. In the process of searching for effective drugs and vaccines for new coronavirus, chloroquine and hydroxychloroquine were once highly expected, and U.S. President trump even took the goods personally. However, with more and more experimental results and clinical data, they eventually came down from the altar. At present, novel coronavirus pneumonia has been cancelled by FDA in June, and the WHO (WHO) has also halted the relevant tests. Source: interface news Author: Jin Tingfan, editor in charge: Yang Zeyu_ NF6036

In addition, the French team conducted more detailed animal experiments. They used cynomolgus monkeys as research animals, and designed five different drug use programs to explore the effect of treatment and prevention of new coronavirus infection. The results showed that hydroxychloroquine could not reduce the viral load in experimental animals. At the same time, hydroxychloroquine cant prevent infection. The novel coronavirus pneumonia was not treated with hydroxychloroquine.

In the process of searching for effective drugs and vaccines for new coronavirus, chloroquine and hydroxychloroquine were once highly expected, and U.S. President trump even took the goods personally. However, with more and more experimental results and clinical data, they eventually came down from the altar. At present, novel coronavirus pneumonia has been cancelled by FDA in June, and the WHO (WHO) has also halted the relevant tests.