New laboratory studies have shown that cholesterol actively helps the coronavirus infect human cells by acting as a delivery service.
The findings could explain why people with metabolic disorders such as diabetes and cardiovascular disease, who often have high cholesterol levels, account for a disproportionate number of patients who develop severe Covid-19 symptoms.
Researchers have discovered that SARS-CoV-2, the virus that causes Covid-19, can adhere to cholesterol molecules as they bind to their normal cellular receptor called SR-B1.
In research, Published in the journal Nature Metabolism by researchers from the Chinese Academy of Military Medical Sciences, examines the role of "good" cholesterol, also known as high density lipoprotein (HDL), in coronavirus infection.
The study specifically examined the SR-B1 receptor, which binds to cholesterol molecules and is found in cells throughout the human body, including the lungs, where the coronavirus targets.
Research has shown that SARS-CoV-2 cannot use this receptor directly, but it can use the process of combining cholesterol with SR-B1 to infiltrate cells.
The viral spike on coronavirus - the same one that clings to ACE2 - consists of two parts called subunit 1 and subunit 2.
In their experiments, Chinese scientists have discovered a subunit that can be attached to cholesterol. This means that when cholesterol naturally migrates to its receptor, it also carries the coronavirus to the cell surface.
The researchers say this "increases virus uptake," and the cholesterol receptor "facilitates the entry of SARS-CoV-2 into cells.
“Our study results demonstrate that SR-B1 promotes attachment, entry and infection of SARS-CoV-2 cells,” the researchers explain in their article.
“Thus ... SR-B1 may represent a therapeutic target for limiting SARS-CoV-2 infection.”
This will likely benefit people with certain underlying medical conditions more than others.
“About half of patients with COVID-19 suffer from chronic diseases, mainly cardiovascular and cerebrovascular, as well as diabetes. In addition, increased mortality from COVID-19 is observed in obese or diabetic patients. ”
NHS data for April shows that nearly a third (29 percent) of coronavirus patients have heart disease and nearly a fifth (19 percent) have diabetes.
Previous research by the NHS and Imperial College found that patients with type 2 diabetes are twice as likely to die from Covid-19, and type 1 diabetics are three and a half times more likely to die.