Infra-Red Light Therapy For Nerve Pain

Today's post from painnewsnetwork.org (see link below) concerning light therapy for nerve pain, is another one for the future and is still a long way away from any doctor's standard treatment lists for neuropathy patients but it is interesting and potentially attractive for people living with persistent nerve pain. It may seem as though you've vaguely heard about light therapy for years but that has generally been light therapy for other conditions, or opportunistic people promoting a pretty-much non-existent therapy for anything from aches and pains to cancer pain. This article explains how recent trials are showing that mice with nerve damage respond to infra-red light therapy very well, in relation to their nerve pain. The explanation is logical and equates light therapy to things like capsaicin which causes the nerve cells to retract when stimulated by the capsaicin and thus stop sending pain signals.
All well and good but it's still in the research stage and is a long way from becoming a standard and effective treatment for neuropathic pain...ho hum...nothing new there then but it does no harm to learn about new developments as they happen. 
 

Light Therapy Used to Treat Neuropathic Pain By Pat Anson, Editor April 24, 2018

For someone with peripheral neuropathy, even the slightest touch can cause burning, stinging or shooting pain, usually in the hands or feet.

The pain is caused when the peripheral nervous system is damaged by diabetes, shingles, chemotherapy or some other medical condition. About 8% of adults worldwide suffer from some form of neuropathy. Medications prescribed to dull the pain – such as opioids, anti-depressants or gabapentin (Neurontin) -- often prove to be ineffective, don’t last long or have unwanted side effects.

Scientists in Italy have now discovered an experimental way to treat neuropathy that provides pain relief for weeks at a time without the use of medication. In experiments on laboratory mice, researchers at the European Molecular Biology Laboratory (EMBL) in Rome identified a specific set of nerve cells in mouse skin that play a significant role in neuropathic pain.

When injected with a light-sensitive chemical and then exposed to infrared light, the nerve cells pull away from the skin’s surface and stop sending pain signals. The pain-relieving effects of the light therapy appear to last for weeks.

The accompanying image shows the skin of a mouse, with the nerve cells that are responsible for sensitivity to touch highlighted in green. The neurons are primarily located around hair follicles.

 

The EMBL's research, first reported in the journal Nature Communications, is still in its early stages. But scientists say human skin tissue is similar to that of mice, indicating that light therapy might be effective in managing neuropathic pain in humans.

"In the end, our aim is to solve the problem of pain in both humans and animals," says Paul Heppenstall, PhD, EMBL group leader. "Of course, a lot of work needs to be done before we can do a similar study in people with neuropathic pain. That's why we're now actively looking for partners and are open for new collaborations to develop this method further, with the hope of one day using it in the clinic."

Heppenstall says light therapy works on the treated nerve cells the same way spicy food or capsaicin patches can cause nerve fibers to retract.

"It's like eating a strong curry, which burns the nerve endings in your mouth and desensitizes them for some time," says Heppenstall. "The nice thing about our technique is that we can specifically target the small subgroup of neurons causing neuropathic pain."

There are many different types of nerve cells in skin, which respond to different sensations like vibration, cold, heat or normal pain. Researchers say those cells are not affected by the light treatment. The skin is only desensitized to a gentle touch, breeze, or tickling.

Previous attempts to develop drugs to treat neuropathic pain have mostly focused on targeting single molecules.

"We think however, that there's not one single molecule responsible, there are many," Heppenstall explains. "You might be able to succeed in blocking one or a couple, but others would take over the same function eventually. With our new illumination method, we avoid this problem altogether."

The neuropathic pain in mice was assessed with a simple touch. The mice would normally quickly withdraw their paw when it was gently touched, but after light therapy they exhibited normal reflexive response to touch. The effect of the therapy lasted for a few weeks, until the nerve endings grew back and the gentle touch caused pain again.

https://www.painnewsnetwork.org/stories/2018/4/24/light-therapy-used-to-treat-neuropathic-pain