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This story was featured on our programme, The Research File. Click to hear the full report. (8.01) |
Dead ducks floating in the water in summer may indicate the presence of a dangerous but surreptitious killer disease. Botulism is caused by extremely potent toxins produced by the bacterium Clostridium botulinum. It's these so called botulin toxins that paralyse muscles and can be lethal.
From Threat to Therapy
It may come as a surprise then that the poison has come up trumps over the past decade as a treatment for a huge variety of medical conditions including cerebral palsy, dystonia, chronic back pain, headaches, migraine, excessive drooling and sweating. But the secret lies in administering the right dose of toxin to the right spot in the body.
What botulin toxin in essence does is block the communication between nerves and body tissue. This is useful if you want to stop unwanted signals from the brain reaching a specific place in your body or vice versa.
Muscle Relaxant
Take for instance disorders such as spasticity and dystonia in which some muscles are tense all the time and cause pain or disfigurement.
"By applying the toxin in very local, small doses you can weaken the muscles that are causing the disease and thereby relieve the patient of his or her condition," says Dr. Keith Foster of the Centre for Applied Medical Research (CAMR) in Salisbury in the UK.
Paediatrician Dr. Marion Crouchman, from King's College Hospital in London, uses this approach in the treatment of children who suffer from spasticity.
"Our children enter in a programme and when they want to continue we give them botulin toxin injections every 6 months. We have children who are now on their 10th treatment episode and very often it's the child itself who wants to continue with the treatment because they get more mobility and are more comfortable."
No Sweat
In addition to being a muscle relaxant, botulin toxin can alleviate other more unusual ailments, such as excessive drooling or excessive sweating. Patients suffering from a localized form of hyper-hydrosis sweat excessively at the armpits, feet and palms of the hands. Sometimes their hands are so slippery, they can't even hold a pen or knife. Injecting the affected area with botulin toxin is an effective counter measure says Dr. Bing Thio, a dermatologist at Erasmus University Medical Center in Rotterdam.
"It's the easiest way because you can inject it once or twice and then you have a relief of your problem for 5 to 6 months. But it's also the most expensive treatment for hyper hydrosis compared to other methods, such as a special lotion or a special therapy using a low electric current."
Pain Killer
Botulin toxin has even been successfully used in the treatment of chronic back pain or severe head aches, and scientists are now trying to improve the poison's capacity to kill all kinds of chronic pain. CAMR's Dr. Keith Foster heads the research group that aims to do just this.
"We want to engineer the molecule so that it targets the nerves that transmit pain, rather than the cells that control the muscles. By doing this, we hope to block the nerve stimulation that causes chronic pain and we see a potential use for this in people suffering from cancer."
The first trials are under way in rats, but it will still be years before this use of the engineered form of botulin toxin may become a reality. However, given the current wealth of applications of botulin toxin in modern medicine, and the fact that every year new possibilities for its use are discovered, it's clear that the poison – used in the right doses - has definitely turned from a foe into a friend.
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Tags: botulin toxin, therapy, treatment