Illustration of masks and coronavirus. (Pixabay)
The author suspects that the reason for the spread of Covid-19 is because in the early stages of the disease, sufferers feel fine as if they have not had the virus.
“This study raises the possibility that pain, as an early symptom of Covid-19, could be reduced by the SARS-CoV-2 protein surge because the virus silences the body’s pain signaling pathways,” said Rajesh Khanna, Ph.D., professor in the Department of Pharmacology at University of Arizona School of Medicine, Tucson.
Most medical experts think SARS-CoV-2 infects when spike protein viral proteins attach to ACE2 receptors on human cells.
In fact, the virus can also use a second receptor, neuropilin-1, to enter the human body.
Khanna explains that many biological pathways signal the body to feel pain. One of them is through a protein called vascular endothelial growth factor-A (VEGF-A).
These proteins play a vital role in blood vessel growth, but have also been linked to diseases such as cancer, rheumatoid arthritis and, most recently, Covid-19.
“Like a lock in a padlock, when VEGF-A binds to neuropilin receptors, they initiate a series of events that result in neuronal hyperexcitability, leading to pain.” he continued.
The research team found the SARS-CoV-2 protein binds to neuropilin in exactly the same part as VEGF-A.
They used rodents to prove this theory, using VEGF-A as a trigger to induce neuronal excitability, which creates pain, then adding the SARS-CoV-2 spike protein.
“The spike protein actually reverses the VEGF-induced pain signal. Regardless of the dose given, whether high or low, it completely relieves pain,” he added.
As well as explaining the possible widespread spread of Covid-19y, the researchers also said their findings could help scientists develop non-opioid therapies.