Botulinum neurotoxin found to travel in nerves

Botulinum neurotoxin – commonly known as Botox – has been found to travel via the body’s nerves back to the central nervous system on its path to the intended destination, according to researchers at The University of Queensland’s Brain Institute (QBI).

Used for its ability to promote local and long-term paralysis of over-active muscles and spasticity, the toxin has been used for decades to treat various conditions and for cosmetic purposes.

QBI laboratory leader Professor Frederic Meunier, commented on the findings: “The discovery that some of the injected toxin can travel through our nerves is worrying, considering the extreme potency of the toxin,” he said. “However, to this day no unwanted effect attributed to such transport has been reported, suggesting that Botox is safe to use.”

The discovery will likely prompt further research into the pathway, which could lead to the development of new treatments for viruses such as West Nile or Rabies, which are also transported through the body via the nerves.

“While no side-effects of using Botox medically have been found yet, finding out how this highly active toxin travels to the central nervous system is vital because this pathway is also hijacked by other pathogens such as West Nile or Rabies viruses.

Dr Tong Wang, a postdoctoral research fellow in Professor Meunier’s laboratory, added: “For the first time, we’ve been able to visualise single molecules of botulinum toxin travelling at high speed through our nerves. We found that some of the active toxins manage to escape this route and intoxicate neighbouring cells, so we need to investigate this further and find out how.”

A spokesperson from multi-specialty health care company Allergan, which produces botulinum toxin products, said of the findings: “This is an animal-only model study which means there is no relevance for humans. Botulinum toxin has been used in humans for therapeutic and cosmetic use for over 20 years and has shown no problems with adverse events in this area.”