Chloroquine does not help against SARS-CoV-2
The Malaria drug chloroquine was considered as the bearer of hope against COVID-19. It has been used for the treatment of patients with COVID-19 and in clinical studies. By now, most professional recommend people to this treatment. A new study shows that chloroquine blocks the SARS-CoV-2 infection of lung cells.
The Malaria drug chloroquine was one of many professionals for a long time the most promising drug candidates in the search for a COVID-19-therapy. But months ago, Researchers reported in the journal “The Lancet” that the drug is likely to be for the treatment of COVID-19-Ill-possibly even the death rate increases. Now, there are new insights to the preparation.
Approved drugs tested
Already more than 600,000 people worldwide have fallen by the Coronavirus SARS-CoV-2 caused disease COVID-19 to the victim. In order to obtain as quickly as possible is an effective therapy for COVID-19, are currently being tested drugs that are already used for the treatment of other diseases.
The current message according to the Department of infection biology of the German Primate center (DPZ) – Leibniz Institute for Primate research in Göttingen, Germany together with colleagues could not show at the Charité in Berlin, that the Malaria drug chloroquine which has been shown to inhibit the SARS-CoV-2 infection of kidney cells of Green monkeys (monkey), is able to prevent infection of human lung cells with the novel Coronavirus.
Therefore, chloroquine does not inhibit the spread of the Virus in the lungs is likely and should not be used for the treatment of COVID-19 used. The results of the study, which was conducted in cooperation with the Charité in Berlin and the Rheinischen Friedrich-Wilhelms-University of Bonn have been published in the scientific magazine “Nature”.
Different routes of Entry into the host cells
As the communication explains, it is known that SARS-CoV-2 is able to use different routes of Entry into the host cells. On the one hand, the pathogen can coalesce after deposition of the cells directly with the membrane and its genetic material into the host cell infiltration, on the other hand, the Virus can enter through Invagination of the host cell membrane and Budding of transport structures, called Endosomes, into the Interior of the cells.
In both cases, the attachment of the Virus to the cells, and the subsequent admission by the Spike-mediated Protein of the Coronavirus. According to the figures, the Spike needs to be activated-Protein either by the enzyme Cathepsin L (in Endosomes) or by the enzyme TMPRSS2 (at the cell surface). Depending on the cell type, both enzymes or only one of them can stand for the activation.
Agent acts only cell-type-specific
Chloroquine is a medicine used for the treatment of Malaria. Because the drug inhibits the infection of monkey kidney cells with SARS-CoV-2, chloroquine, was tested as a possible candidate for the treatment of COVID-19 in clinical studies. How the drug inhibits the infection of monkey kidney cells, however, was unclear.
The current study shows that chloroquine inhibits the Virus entry into these cells, probably by inhibition of Cathepsin L. This has raised the question of whether chloroquine also inhibits the infection of lung cells, by which it is known that they produce, although TMPRSS2, but only a little Cathepsin L.
According to the researchers, it was demonstrated that chloroquine inhibits the SARS-CoV-2 entry into human lung cells and the subsequent spread of the Virus in these cells.
“We were able to show in this study that chloroquine acts only specific to the cell type and the infection of lung cells is not blocked. This means that in the future testing of potential COVID-19-drugs from the outset, care should be taken that relevant cell lines not be used for the investigations in order not to lose time unnecessarily, and to identify as quickly as possible, effective therapeutics,“ says Stefan Pöhlmann, head of the Department of infection biology at the DPZ.
He adds: “The COVID-19 disease is caused primarily by the infection of lung cells, for this reason, these cells should have efficacy tests always take priority.” (ad)