Botox impacts brain? Italian animal study raises safety concerns about botulinum toxin

June 1, 2008

A recent animal study has shown that botulinum toxin injections can travel through retrograde axonal transport to unintended sites, including those in the brain, according to researchers at the Italian National Research Council's Istituto di Neuroscienze.

Key Points

Pisa, Italy - A recent animal study has shown that botulinum toxin injections can travel through retrograde axonal transport to unintended sites, including those in the brain, according to researchers at the Italian National Research Council's Istituto di Neuroscienze. For the study, researchers injected 48 rats, and three days later, found evidence of robust neurotoxin activity on the contralateral side of the hippocampus (Antonucci F, et al. J Neurosci. 2008 Apr 2;28(14):3689-3696).

"Our findings provide the first evidence for a mechanism by which botulinum toxin A can gain access to the central nervous system after peripheral administration," the authors write.

However, "The study authors used a laboratory preparation of botulinum toxin that was different than Botox (Allergan)," says Caroline Van Hove, Allergan's vice president of corporate communications.