One of the main reasons Botox has been a successful
cosmetic agent is because scientists felt the botulinum toxin is localized and
cannot travel to the nerves of the brain and spinal cord. However a new Italian
study has sparked concern after it was found that the toxin can indeed travel
against nerve signals and can penetrate the brain and spinal cord.
Researchers at Italy's Institute of Neuroscience led by
Matteo Caleo, performed an experiment on lab mice to analyze the location of
botox after it was injected in doses comparable to human doses. Botulinum
neurotoxin type A was used in the experiment.
The researchers injected the toxin into whickers and also
into one side of the hippocampus. They found that after three days, botox had
traveled against the direction of the nerves and from one side of the
hippocampus to the other.
The toxin also disrupted the neurons located in the
brainstem and made them sluggish.
"The discovery was quite serendipitous ... and
surprising," Matteo Caleo told the journal Science. "A significant
portion of the toxin is active where it's not intended to be."
The study gives cause for concern, because there have
been 1,437 adverse events associated with Botox use in people from 1989 to
2003. Advocacy group Public Citizen raised the alert after it found 16 deaths
associated with Botox use in FDA's database. The FDA is conducting a safety
review of the same.
The Italian study
showing the ability of botox to travel to the brainstem appears in The Journal