Used to lower cholesterol levels, statins would reduce the risk of serious Covid-19 infection because they eliminate the cholesterol used by the virus to infect the body.
- By removing cholesterol from cell membranes, used by SARS-CoV-2 to enter lung cells, statins are thought to reduce the severity of the infection.
- This discovery opens the way to new therapeutic avenues, using the CH25H gene, which inhibits the ability of the virus to penetrate cells.
While there is currently no vaccine or treatment to fight against SARS-CoV-2 infection, using drugs already on the market because they are considered safe for humans is one of the preferred therapeutic avenues. by many health agencies around the world to fight the Covid-19 epidemic.
While the effectiveness of certain treatments, such as the antiviral remdesivir, is still debated within the scientific community, other classes of drugs have shown encouraging results. This is particularly the case with statins, cholesterol-lowering drugs used to lower cholesterol levels, and which are the subject of new work published in theAmerican Journal of Cardiology.
According to their authors, from the University of San Diego (USA), statins are associated with a reduced risk of developing a severe form of Covid-19, as well as faster recovery times. In question: this elimination of cholesterol from cell membranes would prevent the coronavirus from entering them, estimates another study, published this time in The EMBO Journal.
Less severe form and better recovery
To penetrate lung cells and establish respiratory infections, SARS-CoV-2 uses a molecule called ACE2. This is found on the surface of most human cells, where it helps regulate and lower blood pressure.
It is therefore necessary to block this “door handle” used by the coronavirus to reach the lung cells. Statins, which affect the ACE2 molecule, could be the answer.
To test the effectiveness of this class of cholesterol-lowering drugs, researchers retrospectively analyzed the medical records of 170 patients with Covid-19 and 5,281 control patients hospitalized at UC San Diego Health between February and June 2020. They collected anonymous data including disease severity, length of hospital stay, outcomes, and use of statins, angiotensin-converting enzyme (ACE) inhibitors, and angiotensin II receptor antagonists (ARBs) within 30 days of hospital admission.
Of the patients with Covid-19, 27% were actively taking statins on admission, while 21% were taking an ACE inhibitor and 12% an ARB.
The researchers then discovered that taking statins before hospitalization for Covid-19 reduced the risk of developing a severe form of the disease by 50%. Patients on statins also recovered faster than those not taking cholesterol-lowering drugs.
“We found that statins are not only safe but also potentially protective against severe Covid-19 infection, says Professor Lori Daniels, director of the Cardiovascular Intensive Care Unit at UC San Diego Health. Statins can specifically inhibit SARS-CoV-2 infection through its known anti-inflammatory effects and binding abilities as this could potentially halt the progression of the virus.”
The key role of the CH25H gene
How can this protective effect of statins against coronavirus infection be explained? Another study, led by Professor Tariq Rana, head of the division of genetics in the Department of Pediatrics at the University of San Diego Medical School, looked at the action of statins on a gene called CH25H, which encodes an enzyme that modifies cholesterol. “I was excited because with HIV, Zika and a few others, we knew that CH25H blocks the ability of the virus to enter human cells.”reports the researcher.
By testing the enzymatic activity of the CH25H gene, the research team found that it produced another enzyme called ACAT, which depletes the cholesterol present on the cell membrane. She therefore exposed SARS-CoV-2 to the CH25H gene: this then inhibited the ability of the virus to enter cells, thus almost completely blocking the infection. “The difference between untreated cells and those treated with 25HC was like night and day.”says Professor Rana.
While SARS-CoV-2 uses the ACE2 receptor to initially attach to a cell, Rana’s study suggests that the virus also needs cholesterol (normally present in cell membranes) in order to fuse with the cell and d enter it. 25HC removes much of the cholesterol from this membrane, preventing virus entry.
Similarly, statins are likely beneficial in preventing or reducing the severity of SARS-CoV-2 infection because, while intended to remove cholesterol from blood vessels, they also remove cholesterol from cell membranes. Therefore, the coronavirus cannot enter it.
Now researchers want to develop the CH25H gene as a therapy. According to them, it could prove to be even more effective as an antiviral than statins because it acts specifically on the cholesterol of cell membranes, and not on cholesterol throughout the body. Additionally, statins can cause negative side effects, including digestive problems and muscle pain, and may not be an option for many people with Covid-19.
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