With gene therapy, scientists develop opioid-free solution for chronic pain

A gene therapy for chronic pain could offer a safer, non-addictive alternative to opioids. Researchers at the University of California San Diego developed the new therapy, which works by temporarily repressing a gene involved in sensing pain. It increased pain tolerance in mice, lowered their sensitivity to pain and provided months of pain relief without causing numbness.

The gene therapy could be used to treat a broad range of chronic pain conditions, from lower back pain to rare neuropathic pain disorders – conditions for which opioid painkillers are the current standard of care.

"What we have right now does not work," said first author Ana Moreno, a bioengineering alumna from the UC San Diego Jacobs School of Engineering. Opioids can make people more sensitive to pain over time, leading them to rely on increasingly higher doses. "There's a desperate need for a treatment that's effective, long-lasting and non-addictive."

Moreno's project focused on exploring potential therapeutic avenues. One day, she came across a paper about a genetic mutation that causes humans to feel no pain. This mutation inactivates a protein in pain-transmitting neurons in the spinal cord, called NaV1.7. In individuals lacking functional NaV1.7, sensations like touching something hot or sharp do not register as pain. On the other hand, a gene mutation that leads to overexpression of NaV1.7 causes individuals to feel more pain.

When Moreno read this, it clicked. "By targeting this gene, we could alter the pain phenotype," she said. "What's also cool is that this gene is only involved in pain. There aren't any severe side effects observed with this mutation."