Researchers at the University of Queensland’s Queensland Brain Institute have found that some of the Botox (Botulinum neurotoxin serotype A) used for cosmetic injections escapes into the central nervous system. Laboratory leader Professor Frederic Meunier said the discovery was worrying.
“While no side effects of using Botox medically been found yet, finding out how this highly active toxin travels to the central nervous system is vital because the pathway is also hijacked by other pathogens such as West Nile or Rabies viruses,” he said.
Postdoctoral Research Fellow Dr Tong Wang 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 managed to escape this route and intoxicate neighbouring cells, so we need to investigate this further and find out how.”The research, published in the Journal of Neuroscience, was a collaboration between scientists at Queensland Brain Institute, Australian Institute for Bioengineering and Nanotechnology and School of Chemical Engineering as well as the CSIRO and teams from the US, France and the UK.
The use of Botox in the UK is regulated by the Medicines and Healthcare products Regulatory Agency (MHRA). In 2007, it issued a drug safety update warning about the ‘rare but serious risk’ of adverse reactions from the distant spread of the toxin, especially for patients with neurological disorders or a history of dysphagia or aspiration. However, it considers the toxin’s safety profile to be otherwise acceptable and its use for medical conditions such as urinary incontinence and migraine have since been approved. In the US, its use is regulated by the FDA. In 2009, the agency issued a notice to manufacturers to strengthen warnings on product labelling about the risk of reactions as a result of toxin spread.
