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New Gene Therapy Eliminates Chronic Pain

Posted on: Wednesday, 23 January 2008, 17:00 CST

Researchers at Mount Sinai School of Medicine were able to eliminate chronic pain for at least three months in rats who were given spinal injections of a new gene therapy that triggers the body’s natural pain killer endorphin.

The scientists hope the new discovery will revolutionize the way chronic pain is treated and managed.

The therapy did not affect the rest of the nervous system, potentially preventing the principal side-effects seen in current treatments for chronic pain.  

"Fifty million Americans suffer from chronic pain. Chronic pain patients often do not experience satisfactory pain relief from available treatments due to poor efficacy or intolerable side effects like extreme sleepiness, mental clouding, and hallucinations," said Dr. Beutler.

He said that in some circumstances, patients preferred to continue suffering some pain in order to preserve lucidity.  Also, there is a potential risk of addiction to opiate drugs.

In the study, the team used a disabled cold virus to carry the gene into the spinal fluid of rats that had been developed to suffer chronic pain.

The therapy then blocked the pain impulses traveling up to their brains, which allowed the rats to remain pain-free for at least three months, the researchers wrote in the report.

"Although this research is at a very early stage, the concept of using gene therapy to deliver pain relief is interesting because it could potentially have fewer side effects than conventional pain relief," Josephine Querido of Cancer Research UK told BBC News.

"Targeted gene therapy will likely avoid the unwanted side effects associated with opioid painkillers such as morphine.  Based on our findings, this targeted gene therapy via lumbar puncture appears to be a promising candidate for bench-to-bedside research that might ultimately be tested in patients with intractable chronic pain, e.g., to help patients suffering from severe pain due to advanced cancer."

Studies show  drugs do not relieve chronic pain in up to two-thirds of cancer patients .

While cancer patients could be among the main beneficiaries of this therapy, a recent study showed that as many as 20% of adults suffer from chronic or intermittent pain, such as back  and neck pain, for which no satisfactory treatment is available.

Scientists have been trying for many years now to harness gene therapy for pain relief but have hit various obstacles along the way.

This development is "certainly exciting and promising, but it is a little too early to say what the ultimate significance of the results is.  Once the researchers have shown that in animal models of chronic pain, there is long-standing improvement, one could start speaking of a medical breakthrough." Said Professor Turo Nurmikko, Director of the Pain Research Institute in Liverpool.

The study "Sensory neuron targeting by self-complementary AAV8 via lumbar puncture for chronic pain" was published in the January 22, 2008 issue of the Proceedings of the National Academy of Sciences (PNAS).

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Mount Sinai School of Medicine

Source: redOrbit Staff

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