Bradykinin Hypothesis Could Change COVID-19 Treatment

COVID-19 gets the door prize for infection with the most surprises. It seems no matter how many answers experts find, the questions keep piling up, but we may have finally turned the corner. New research is shedding greater light on the reasons some people get so much sicker than others, and that could mean good news for future treatment options. 

What are “Bradykinin Storms”?

One reason COVID-19 is so dangerous is that it can cause intense inflammation in the lungs and other vital organs. Until recently, researchers focused on the cytokine storm, a type of unchecked immune response that becomes harmful and leads to severe tissue damage. Patients hospitalized with COVID-19 have consistently shown evidence of this reaction via blood tests, but cytokines aren’t the only chemicals that can cause this kind of inflammation.

A peptide called bradykinin (BK), which helps regulate blood flow and fluid balance, also seems to be a factor. A study recently published in eLife shows how altered BK levels contribute to inflammation in the lungs. COVID-19 relies on a specific receptor that exists on many types of human cells, ACE2, which also appears to affect BK levels. When inflammation strikes, BK levels rise. This alone isn’t the problem. The issues that cause inflammation can also create conditions that break down BK, while also reducing the body’s ability to clear out the by-products. This can lead to increased inflammation, fluid retention, and leaky blood vessels.

On top of this, the researchers found COVID-19 infections can increase the number of ACE2 receptors in certain tissues, making them even more susceptible. According to controlled tests, COVID-19 patients can have up to 199 times the normal number of ACE2 receptors in their lungs. Higher levels of ACE2 means even more opportunity for inflammation, causing the response to spiral out of control.

Other Deadly Effects of COVID-19

The researchers also found that COVID-19 causes increases in a compound called hyaluronic acid (HA), which normally helps keep tissues hydrated and lubricated. HA expands into a hydrogel as it takes on water, up to 1000 times its own weight. HA absorbs all that excessive fluid caused by increased BK levels, expanding as a sort of gelatin into the lungs’ air sacs and obstructing the airways. This can lead to plummeting oxygen levels and crashes in vital organ function.

The Good News

These effects may sound scary, but the bradykinin hypothesis could be the key to beating this pandemic. Doctors already have a list of medications that affect BK and HA levels, so exploration into those drugs might lead to improved COVID-19 treatments. With any luck, controlling BK and HA levels may reduce infection severity. Without the “bradykinin storm” to complicate lung inflammation, patients might be spared the acute respiratory distress that causes too many severe patients to go downhill so quickly.

Researchers have been looking, tirelessly, for ways to get ahead of the COVID-19 pandemic, and their hard work may be paying off. This virus might not be finished with us yet, but we can turn the tide. Hopefully, this new information will help make that happen.

Copyright 2020, Wellness.com