Botox Study Shows Migration to the BrainApr 3, 2008 | Parker Waichman LLP
A new Botox study indicates that the antiwrinkle treatment could actually migrate from a recipient's face to the brain. Botox is made with botulism toxin, one of the world's most poisonous substances, which can lead to a paralyzing illness. Word of this latest Botox study - published in the latest issue of the Journal of Neuroscience - comes just weeks after the Food & Drug Administration (FDA) announced that it was beginning a safety review of Botox and other similar drugs.
Botox, which is made with botulinum toxin type A, is approved in the US for treatment of conditions such as blepharospasm (spasm of the eyelids), cervical dystonia (severe neck muscle spasms), and severe primary axillary hyperhydrosis (excess sweating). Botox Cosmetic, which also uses botulinum toxin Type A, is approved for temporary improvement in the appearance of moderate to severe facial frown lines. A similar drug, Myobloc, is made from botulinum toxin Type B, and is approved for the treatment of adults with cervical dystonia.
According to the FDA, there have been reports of Botox, Botox Cosmetic and Myobloc reactions that are suggestive of botulism, which occurs when botulinum toxin spreads in the body beyond the site where it was injected. The most serious cases had outcomes that included hospitalization and death, and occurred mostly in children treated for cerebral palsy-associated limb spasticity. Use of botulinum toxins for treatment of limb spasticity (severe arm and leg muscle spasms) in children or adults is not an approved use in the U.S.
Now, scientists from the Italian National Research Council's Institute of Neuroscience in Pisa who were conducting experiments with Botox in rats have found that the toxin can make its way to the brain in those lab animals. Although rats and humans have a different physiology and their responses may vary, the researchers said say the results should lead to more research.
In the study, the whisker muscles of rats were injected with the toxin. Within three days, the scientists discovered traces of potentially deadly botulism in the rodents' brain stems. The study's author, Matteo Caleo, said the toxin also moved from one hippocampus, which controls long-term memory and spatial navigation, to the hippocampus on the other side of the rat's brain. The botulism toxin was still present in the rats' brains after six months.
Last month, another Botox study conducted by researchers at the University of Calgary experimenting on cats also found that the botulism toxin from Botox could migrate to other parts of the body. The Calgary team injected the toxin into a muscle at the back of the leg of cats. Four weeks later, the time it takes for Botox to have its full effect, they measured the strength of this muscle, and that of a neighboring muscle. The Botox study revealed the toxin passed easily into the surrounding muscles and weakened all the muscles in the area. The results support other research that has already shown that botulinum can pass through tissue surrounding muscle.
Allergan, the California-based company that makes Botox, told the UK newspaper "The Daily Mail" that the Italian research was not conclusive and contradicted previous findings. "The authors used a laboratory preparation of botulinum toxin and did not use Botox," said a spokesman. "Data suggests that different preparations of botulinum toxin react differently in both the laboratory and in clinical practice."