A new study by University of Arizona Health Sciences researchers reveals that the virus that causes COVID, SARS-CoV-2, has pain relieving effects which may assist in addressing the ongoing opioid epidemic.
The U.S. Centers for Disease Control and Prevention released data in early September that estimated about 50 percent of COVID transmission happens before symptoms show up, and that 40 percent of those infected with COVID are asymptomatic.
The study’s corresponding author, Rajesh Khanna, said that this finding may explain why almost half of those diagnosed with COVID experience only a few symptoms or are completely asymptomatic, despite having the ability to spread the disease.
“It made a lot of sense to me that perhaps the reason for the unrelenting spread of COVID-19 is that in the early stages, you’re walking around all fine as if nothing is wrong because your pain has been suppressed,” Khanna told Medical Express. “You have the virus, but you don’t feel bad because your pain is gone. If we can prove that this pain relief is what is causing COVID-19 to spread further, that’s of enormous value.”
What the Research Said in Arizona
University of Arizona Health Sciences’ Senior Vice President Michael D. Dake explained that the research suggests that pain, as an early symptom of the virus, could be lessened by the SARS-CoV-2 spike protein.
He told Medical Express, “University of Arizona Health Sciences researchers at the Comprehensive Pain and Addiction Center are leveraging this unique finding to explore a novel class of therapeutics for pain as we continue to seek new ways to address the opioid epidemic.”
Scientists initially indicated that the SARS-CoV-2 spike protein uses the angiotensin-converting enzyme 2 (ACE 2) receptor to enter the body, but new research in June established neuropilin-1 as a second receptor for SARS-CoV-2.
This is what made researchers at the University of Arizona realize that the spike protein could potentially be involved in pain processing.
How the Body Processes Pain
There are different biological pathways that help the body process pain.
As Medical Express explained, “One is through a protein named vascular endothelial growth factor-A (VEGF-A), which plays an essential role in blood vessel growth but also has been linked to diseases such as cancer, rheumatoid arthritis, and most recently, COVID-19.”
When VEGF-A binds to receptor neuropilin, it results in a hyperexcitability of neurons, thus leading to the body feeling pain. Khanna and other University of Arizona researchers found that the SARS-CoV-2 spike protein binds to neuropilin in the same place as VEGF-A.
This information led to them conducting a number of experiments and rodent models to test their theory about SARS-CoV-2 acting on the VEGF-A/neuropilin pain pathway. Using VEGF-A to instigate neuron excitability, they then added the SARS-CoV-2 spike protein. They found that it reversed the VEGF-induced pain signaling completely, no matter the dosage.
Following these results, Khanna will now be continuing research on the relationship between neuropilin and the spread of COVID-19 with a team of immunologists and virologists at UArizona Health Sciences. He will also be examining neuropilin as an option for non-opioid pain relief.
He told Medical Express, “We have a pandemic, and we have an opioid epidemic. They’re colliding. Our findings have massive implications for both. SARS-CoV-2 is teaching us about viral spread, but COVID-19 has us also looking at neuropilin as a new non-opioid method to fight the opioid epidemic.”
This study will soon be published in the Journal of the International Association for the Study of the Pain.
By Cara Nixon