A gene therapy has been able to inhibit neuropathic pain with no detectable side effects in mice with spinal cord and peripheral nerve injuries. The corresponding study was published in Molecular Therapy.
Neuropathy involves damage or dysfunction in nerves and typically results in chronic or debilitating numbness, tingling, muscle weakness, and pain. Currently, there are no effective treatments for the condition. Current pharmaceutical therapies are often complex and have undesirable side effects, including sedation. Opioids may also be used. However, they open a risk for abuse.
In the present study, researchers used a gene therapy to treat neuropathic pain in mice. The therapy involved injecting a harmless adeno-associated virus carrying transgenes that encode for gamma-aminobutyric acid (GABA)- an inhibitory neurotransmitter- into mice with sciatic nerve injuries.
The researchers reported that the production of GABA by the transgenes inhibited pain signaling neurons in the mice, and that these effects lasted for at least 2.5 months following treatment. They noted that treated animals demonstrated both a progressive and complete reversal of neuropathic pain- this denoted by differences in tactile and brush-evoked pain behavior.
The researchers were able to localize the treatment as they were able to locate the precise injury location. This, they suggest, limited side effects and may explain why they observed no side effects between 2-13 months post-treatment in adult mice, pigs, and primates.
"One of the prerequisites of a clinically acceptable antinociceptive (pain-blocking) therapy is minimal or no side effects like muscle weakness, general sedation or development of tolerance for the treatment," said senior author of the study Martin Marsala, MD, professor in the Department of Anesthesiology in the UC San Diego School of Medicine.
"A single treatment invention that provides a long-lasting therapeutic effect is also highly desirable. These findings suggest a path forward on both," he concluded.
Sources: Science Daily, Molecular Therapy