Scientists have developed a modified form of Botox that could give long-term pain relief to patients with persistent nerve injury.
Botox is the brand name of a muscle relaxant that is injected into the face in small doses to smooth out lines and wrinkles.
It is a protein made from Botulinum toxin, which the bacterium Clostridium botulinum produces.
However, Botulinum toxin is dangerous in large quantities and can temporarily paralyse muscles.
Much like cosmetic Botox, the effects of the modified Botox can last for up to five months, although it has not yet been tested on humans.
The team said its work, published in the journal Life Science Alliance, could help provide relief for those who find chronic pain hard to manage – as drugs that are currently available are limited by dangerous side effects.
Dr Maria Maiaru, from the University of Reading, said: “People with chronic pain need new options for managing their symptoms.
“They need safer and more effective drugs.
“These new Botulinum molecules are effective in reducing pain-like behaviour in models of human pain.
“We believe that this approach could open the way for the development of pain treatment to improve the quality of life of millions of people living with chronic pain.”
It is estimated that about seven in every 100 people in the UK have chronic nerve pain.
Drugs such as morphine and fentanyl can only be used for short-term pain relief due to the risk of addiction, abuse, and overdose associated with long-term use.
Scientists from the Universities of Sheffield and Reading, University College London (UCL), and US-based biopharmaceutical company Neuresta, developed a new way of rebuilding Botox by using elements of C. botulinum.
The researchers said they broke Botox into two separate parts and rebuilt an “elongated” version.
When tested on rats, this modified Botox was found to be non-toxic and did not cause paralysis.
Professor Bazbek Davletov, from the University of Sheffield’s School of Biosciences, said: “Currently, painkillers can only relieve chronic pain temporarily and often have unwanted side effects.
“A single injection of the new nonparalytic blocker at the site of pain could potentially relieve pain for many months in humans and this now needs to be tested.
“We hope that the engineered drug could improve the quality of life for the millions of people worldwide who suffer from chronic pain.”
The results from the research have led to the transfer of the technology to a US-based biopharmaceutical start-up company Neuresta, which is now working on tailoring nerve blockers to different neurological conditions using the technique.
The research was funded by the UK Medical Research Council (MRC).