Can the new coronavirus block pain signals?

  • The spike protein in the SARS-CoV-2 virus could be blocking pain in infected nerve cells
  • A new study has found that it can interrupt pain signals to potentially hide itself in asymptomatic infections
  • The research could open doors for new approaches to pain management

It's hard to think that anything good can come out of Covid-19 infection, but some scientists have become very interested in the virus's ability to block pain. It could signal a new approach to pain research and medication.

In a pre-print study to be published soon, scientists looked at the effect SARS-CoV-2 has on pain receptors. Studies have found that it can bind with sensory neurons expressing ACE2 receptors – its favourite gateway – like neuropilin-1, which can inflict pain when interacting with the protein vascular endothelial growth factor A (VEGF-A). 

Normally, it encourages the growth of new blood cells, but in this instance, it instead sends pain signals via the spinal cord to the brain.

READ | Children’s immune systems respond differently to Covid-19 than those of adults, research suggests 

Interruption from spike protein

The latest research found that during the binding of the coronavirus's spike protein to a nerve cell, it also blocks signalling from VEGF-A. This led the researchers to hypothesise that the spike protein of the virus could completely block pain.

They tested this on pathogen-free rats and tested their pain tolerance with nerve injuries through various surgeries. They found the coronavirus spike protein was actually interfering with the endothelial protein.

What does this mean for humans? 

"Based on the reported increase in VEGF-A levels in Covid-19 patients, one would expect to observe increased pain-related symptoms," write the scientists.

"However, our data suggest that the SARS-CoV-2 spike protein hijacks [neuropilin-1] signalling to ameliorate VEGF-A mediated pain. This raises the possibility that pain, as an early symptom of Covid-19, may be directly dampened by the SARS-CoV-2 spike protein."

While symptomatic Covid-19 patients complain about pain, it raises questions whether those who are asymptomatic are having their pain blocked by the virus, basically silencing its presence to the host and making it easier to spread undetected.

READ MORE | What experts have learned, and the questions that remain about severe Covid-19-infections

Future of pain treatment

However, one of the study's co-authors, Professor Rajesh Khanna from the University of Arizona, argues in The Conversation that these findings could open up new avenues for pain medication research.

"If our finding that the new coronavirus is attacking cells through a protein associated with pain and disabling the protein can be confirmed in humans, it may provide a new pathway for drug development to treat Covid-19," writes Khanna.

"Our studies identify a different approach because we targeted blocking the pain-triggering VEGF-A protein, which then resulted in pain relief. So our preclinical work described here provides a rationale for targeting the VEGF-A/NRP-1 pro-pain signalling system in future clinical trials."

He believes this approach could potentially also be used to stop viral infections, and for cancer treatment as well.

READ | Paracetamol, most common pain reliever worldwide, induces risky behaviour, new study says

Image credit: iStock

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