Human stem cells help treat chronic pain in mice

Scientists at the University of Sydney have used human stem cells to make painkilling neurons that provide lasting relief in mice, without side effects, in a single treatment — a breakthrough that could lead to the development of new pain management strategies in humans.

Chronic pain is defined as persistent pain that continues after the original injury has healed. It comes in two forms: inflammatory pain and neuropathic pain. The researchers’ study in mice looked at neuropathic pain, which occurs after damage to the nervous system and is usually described as an electrical or shooting pain.

“Existing treatments for neuropathic pain necessitate long-term treatment with repurposed anti-convulsants and antidepressants,” noted Professor Greg Neely, a leader in pain research at Sydney’s Charles Perkins Centre. “These treatments are not specific for pain and have extensive side effects and, importantly, these drugs together seem to really help only around 25% of patients.

“Virtually everyone will experience some form of chronic (untreatable) pain at some stage in their lives,” Prof Neely added. “In view of this immense and unmet problem… new non-opioid, non-addictive, pain management strategies are critical for our ageing society.”

Prof Neely and his team used human induced pluripotent stem cells (iPSCs) derived from bone marrow to make pain-killing cells in the lab, then put them into the spinal cords of mice with serious neuropathic pain. The stem cells used were derived from adult blood samples and the results were published in the journal Pain.

“Remarkably, the stem-cell neurons promoted lasting pain relief without side effects,” said Dr Leslie Caron, co-senior author on the study. “It means transplant therapy could be an effective and long-lasting treatment for neuropathic pain. It is very exciting.”

John Manion, a PhD student and lead author of the paper, added, “Because we can pick where we put our painkilling neurons, we can target only the parts of the body that are in pain. This means our approach can have fewer side effects.”

The team’s next step is to perform extensive safety tests in rodents and pigs, then move to human patients suffering chronic pain within the next five years.

“Nerve injury can lead to devastating neuropathic pain and for the majority of patients there are no effective therapies,” Prof Neely said. “This breakthrough means for some of these patients, we could make pain-killing transplants from their own cells, and the cells can then reverse the underlying cause of pain.

“Thanks to funding from the NSW Ministry of Health, we are already moving towards testing in humans.”

Image credit: ©stock.adobe.com/au/peterschreiber.media

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