Tuesday, June 26, 2007
Botox and Botulism and Celebrity Crazes
As a medical student free time can be scarce. Except, of course, when you have access to celebrity gossip. One week a tummy-tuck, the next week rhinoplasty, all topped off with a face-lift, there are ample excuses to read about the stars as part of my "medical education." Of all these "enhancements," one of the most commonplace is the Botox injection; speculation about the use of which is constantly attributed to various celebs. There are also questions about the safety of the use of this treatment, which may be clearer after learning how it works.
Botox is a medical and cosmetic form of a toxin produced by Clostridium botulinum, a spore-forming bacteria. The Clostridia family of bacteria are gram positive and are obligate anaerobes; they cannot survive in the prescence of oxygen. They have worked around this weakness, however, and can coat themselves in a thick coat to make an environmentally resistant spore. When they find an anaerobic environment, such as the GI tract, the bacteria can uncoat and proliferate.
It is not this proliferation that you need to worry about, at least not directly. The bacteria enacts its damage by releasing an A-B toxin, a two subunit toxin where the B subunit binds a cell and the A subunit is the active agent. In this case, the B subunit binds motor neurons and the A subunit cleaves a protein involved in synaptic vesicle release. Basically, the neurotransmitter acetylcholine, which signals for your muscles to contract and is inside the vesicle, is no longer released and you succumb to flacid paralysis, in a disease process called botulism. This is why Botox is known to smooth wrinkles; it paralyzes that area of the face and so the skin becomes relaxed. It also becomes immobile, and you often see Botox parodied for making patients expressionless.
One of the things to keep in mind is that botulinum toxin is one of the most potent and deadly toxins known to man. Just one picogram (1x10^-12g) of this toxin per kilogram (roughly 2.2lbs) that you weigh is the lethal dose in humans. Incidence of botulinum poisoning is fairly rare; in adults, it is most often seen when someone eats home-canned foods, which provide that anaerobic environment needed for proliferation and toxin release. Interestingly, infants tend to be affected not by ingesting the toxin, but by getting infested with the bacteria in their guts. Infants lack the normal flora that would otherwise occlude the GI surfaces, and so C. botulinum can proliferate when eaten, commonly from honey (spores are in 10% of honey). Botulinum toxin can also be an agent of bioterrorism: since it is so potent, a small amount can be released and incapacitate thousands of people.
In spite of this, botulism is no longer always fatal; affected individuals can be placed on a ventilator and make it through the paralysis. Its diluted relative, Botox, is used both medically and cosmetically and can have a positive role in many treatment plans. Clearly there can be concern with using this extremely potent toxin, but with proper regulation it has a role, as seen in the New York Times article on the business of Botox from last week. While it may be all the rage among the stars, be sure to be safe about any treatment you may seek and consult your physician.