Although pandemics still can’t be contained, researchers continue to try to better understand what causes the most severe cases of Covid-19. This time, they may have identified the molecular mechanism responsible for this mortality; an enzyme related to neurotoxins found in rattlesnakes venom!
What are the Covid treatments?
Scientists have been studying an enzyme they call sPLA2-IIA for nearly 50 years. Some call it a “shredder”.” That’s because, in the event of a bacterial infection, it is capable of destroying the membranes of microbial cells. By attacking the specific fats that these microbes carry on the outside of their membranes. And this has recently come to the forefront again in the context of the Covid-19 pandemic.
Researchers at the University of Arizona now say the enzyme is found in low concentrations in healthy people. It helps protect us from infection. Without risk, because even though human cells carry the fats that are targeted by sPLA2-IIA, it’s more likely to be inside their walls. So they’re safe.
But in sick people, if the cells start to die from an infection, these fats can be exposed. And when sPLA2-IIA circulates in the blood at high levels, the system goes haywire. This enzyme mistakes mitochondria – the energy powerhouses of our cells – for bacteria. Rather than simply targeting foreign cells, it starts ‘shredding our own cells.
A new therapeutic pathway?
Relationship to Covid-19? That’s what researchers identified by analyzing plasma samples from more than 250 patients. A cohort that remains modest but for which all useful chemical parameters were available. This allowed them to confirm a number of risk factors: age, body mass index, and pre-existing conditions. But also to look at biochemical enzymes and levels of lipid metabolites in patients’ blood.
“We were able to identify patterns of metabolites present in people who died from the disease,” study lead author Justin Snider explains in a press release. The correlation between sPLA2-IIA levels and severe Covid-19 suggests that this enzyme may be a critical factor in fatal cases.
In most healthy people, blood levels of sPLA2-IIA are about half a nanogram per milliliter (ng/ml). According to the study, Covid-19 proved fatal in 63% of patients with enzyme levels of 10 ng/ml or more. This is still five times more than in patients who recovered from severe forms. “Many of the patients who died of Covid-19 had the highest levels of this enzyme,” says Floyd Chilton, who has studied sPLA2-IIA for more than three decades. Up to more than 1,000 ng/ml. The discovery could pave the way for new treatments. But more research, and particularly clinical trials, are needed to confirm it.
Articles you may like: