|
|
|
|
|
|
|
VAMPIRE BAT STRIKES STROKE PATIENTS
|
|
Vampires - or more specifically vampire bats - are
showing promise as saviours of stroke patients.
A team of researchers at Monash University in Melbourne has found that an enzyme extracted from the saliva of these bats could be a more effective treatment for breaking down blood clots in the brains of stroke patients than current treatment.
The bat protease, cloned 10 years ago, is very similar to the enzyme humans produce to remove blood clots.
Dr Rob Medcalf, from the department of medicine based at Box Hill Hospital, said the initial research on mice suggested that the vampire bat enzyme could be used to destroy blood clots up to nine hours after an ischaemic stroke without further increasing the risk of brain damage.
Working with Dr Gabriel Liberatore and Andre Samson, from Monash's department of medicine, Associate Professor Chris Bladin, from Eastern Melbourne Neuroscience at Box Hill Hospital, and Dr Wolf-Dieter Schleuning from the PAION GmbH Research Centre in Berlin, he said the key enzyme is called Desmodus rotundus salivary plasminogen activator (DSPA).
DSPA works by targeting and destroying fibrin.
Dr Medcalf said there are two important differences between DSPA and the commonly used treatment, tissue plasminogen activator (t-PA).
"The first is that the bat protease is twice as effective as t-PA in removing a clot, and more importantly, it is active only when the blood clot is present.
"Its activity is entirely dependent on the presence of a blood clot, so that means it has less chance of causing additional side effects when administered intravenously."
He said t-PA is effective only in the first three hours, and after that time there is a high risk of causing injury.
"Animal models have shown that t-PA is neurotoxic under some circumstances, and that may be related in part to the damaging effect it has with longer-term treatment of stroke patients.
"We looked at the potential of the bat protease to cause neurotoxicity and found that bat protease had no damaging effects whatsoever.
"This gives us a chance to look at its potential for longer-term stroke treatment."
"DSPA could be a safe treatment option for a longer period, as it has no detrimental effect on brain cells."
PAION GmbH Research Centre in Berlin has been conducting clinical trials on stroke patients for the last two years in Australia, Europe, and Asia, looking at the safety and effectiveness of the recombinant bat protease.
A trial in the United States began in late 2002.
Sixty patients who arrive at the hospital 3-9 hours after a stroke have already been recruited.
At present there is no treatment for such patients.
"I understand the treatment could then be available in clinics by 2006," Dr Medcalf said.
|
|
|
|
