Stem Cell Transplants Offer Nerve Pain Relief

(NIH.gov)

24 Jan. 2020. Researchers in Australia show in tests with lab mice that transplanted adult stem cells can provide long-term relief from chronic pain caused by nerve damage. A team from University of Sydney’s health research center describe their findings in the February 2020 issue of the journal Pain (paid subscription required).

The search for effective non-addictive chronic pain relief is driven to a large extent by the opioid crisis in the U.S. and elsewhere. Opioid drugs, first designed for acute or temporary pain relief, were often prescribed for chronic pain, since few other options were available. In Australia, some 3.2 million people live with chronic pain at a cost to the country of more than $139 million.

Researchers from the lab of Sydney geneticist Greg Neely are seeking better options for treating chronic neuropathic pain, where shooting pain caused by nerve damage results from nerve disorders like sciatica, traumatic injuries, infectious diseases such as shingles, and herniated spinal discs. A common cause of neuropathic pain, however, is complications from diabetes, known as diabetic neuropathy, where high levels of glucose in the blood result in damage to nerves in limbs and elsewhere, with chronic pain among the symptoms.

“Existing treatments for neuropathic pain,” says Neely in a university statement, “necessitate long term treatment with repurposed anti-convulsants and anti-depressants. These treatments are not specific for pain and have extensive side effects and importantly, these drugs together seem to really help only around 25 percent of patients.”

Earlier experiments with embryonic stem cells show promise for transforming into healthy neurons or nerve cells to provide chronic pain relief. For the new study, the Sydney team used induced pluripotent stem cells, also known as adult stem cells, since they’re derived from a patient’s own cells. The researchers extracted stem cells in this case from human bone marrow, which transform into neurons interacting with gamma aminobutyric acid, or GABA, a neurotransmitter that blocks brain signals, including pain signals.

The team gave the stem cells to lab mice induced with neuropathic pain from spinal cord injuries, by transplanting the cells into the mice spinal cords. Results show the stem cells survive for extended periods in the recipients’ spinal cords and integrate with synapses, electrical nerve signaling junctions.

Research fellow and co-author Leslie Caron notes that “the stem-cell neurons promoted lasting pain relief without side effects. It means transplant therapy could be an effective and long-lasting treatment for neuropathic pain.” The team attributes a lack of side effects to transplanting the stem cells at the site of the injury.

The researchers believe their findings prove the concept of stem cell transplants for pain relief, but considerably more work remains, including more preclinical studies with larger lab animals. Human clinical trials are not expected for another five years.

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