Could a common antioxidant enzyme help treat COVID-19?
Written by Lori Uildriks, Pharm.D., BCPS, BCGP on October 5, 2020 — Fact checked by Alexandra Sanfins, Ph.D.
New research suggests that catalase, a naturally occurring enzyme in humans, plants, and animals, can suppress the replication of the new coronavirus in rhesus monkeys. The results also indicate that this low cost enzyme could dampen the inflammatory response that occurs in severe COVID-19.
Share on PinterestAbove, a computer-generated illustration shows a cytokine storm, the excessive immune response that researchers are looking to prevent in COVID-19.
Image credit: selvanegra/Getty Images.
The COVID-19 pandemic has had a devastating effect in the United States and worldwide.
As of October 5, 2020, the Johns Hopkins Coronavirus Resource Center Dashboard reported 209,734 and 1,037,604 COVID-19-attributed deaths in the U.S. and globally, respectively. Currently, there is a lack of specific antiviral agents to treat COVID-19 and no preventive vaccine.
Some evidence suggests that severe cases of COVID-19 may be the result of an abnormal overactive immune response known as a cytokine storm. Without treatment, a cytokine storm may result in substantial morbidity and mortality.
Stay informed with live updates on the current COVID-19 outbreak and visit our coronavirus hub for more advice on prevention and treatment.
The issue of cytokine storms
Infection with the SARS-CoV-2 virus, which causes COVID-19, triggers a local immune response. White blood cells infiltrate the tissue, causing the excessive production of reactive oxygen species (ROS).
Increased levels of ROS cause hydrogen peroxide to accumulate in tissues, leading to tissue damage, hyperinflammation, and increased viral replication. ROS further promote cytokine release.
The overproduction of inflammatory cytokines can occur in severe cases of COVID-19. Treatment to reduce the production of cytokines and the inflammatory response may, therefore, help treat this disease.
Immunosuppressive medications that doctors currently use to treat cytokine storm include steroids, intravenous immune globulin, Janus kinase inhibitors, and cytokine blockers, such as anakinra or tocilizumab. However, some of these medications are expensive, and side effects may complicate therapy.
This is where catalase comes into play. Catalase is a naturally occurring antioxidant enzyme present in the liver, red blood cells, and alveolar epithelial cells — the cells that line the insides of the alveoli in the lungs.
It effectively breaks down hydrogen peroxide in the body into oxygen and water. Catalase is also currently available as a dietary supplement and food additive.
Researchers from the University of California, Los Angeles (UCLA), the Beijing University of Chemical Technology in China, and other Chinese institutions recently speculated that catalase could decrease hydrogen peroxide levels in the body.
This, they said, could minimize downstream ROS levels and cytokine release, ultimately suppressing the excess inflammation, oxidative cell injury, and viral replication that occur in severe COVID-19.
To confirm their hypothesis, the team of scientists set out to conduct several experiments — in cell cultures and rhesus macaque monkeys — using n(CAT), catalase nanocapsules that consist of catalase molecules coated with a thin shell of polymer. This coating enhances stability and prolongs the time that catalase remains in the blood.
The researchers report their findings in the journal Advanced Materials.