Research Breakthrough to better protect stroke sufferers
Our scientists have discovered a potential way to improve the world's only stroke drug, a breakthrough which may better protect stroke sufferers from brain injury.
"Given that we have just one therapy for stroke, this new insight will enable us to significantly improve upon current treatments, which could improve quality of life for the thousands who suffer strokes each year," says Professor Shaun Jackson, senior investigator of the work published in the prestigious international science journal Nature Communications.
Heart attacks and stroke are two of the leading causes of death and long-term disability in New Zealand. Both conditions are typically caused by blood clots in the circulation of the heart or brain.
The mainstream treatment for these diseases is a clot busting therapy called tissue plasminogen activator or ‘tPA’ that works by restoring blood flow to blocked arteries to prevent damage to the heart and brain.
"It's given to patients in the few hours immediately after they have a stroke, quickly dissolving the clots and saving thousands of lives," explains Professor Jackson, who is the Thrombosis Group Leader and Director of Cardiovascular Research at the Heart Research Institute and Charles Perkins Centre.
But tPA is a Jekyll and Hyde drug with a dark side. While doing its good work, it also promotes inflammation in the brain, triggering further brain injury.
Professor Jackson and his team have discovered how this dark side operates.
‘We found that blood clots can slow down the white blood cells and stop them causing damage in the brain's tissue. But when you inject lifesaving tPA, it dissolves this protective barrier, allowing them to flood in and cause a lot of damage," the scientist says.
"Now we know that this is what's happening we can develop a new blocking therapy to be given alongside tPA to stop the blood cells from rushing in and dramatically improve outcomes for patients."
Hundreds of drugs have been trialled for use in stroke, yet tPA remains the only successful clot buster that is available in the clinic. It is the frontline treatment given to patients who get to hospital quickly after suffering a stroke.
"We like to get it into patients to reopen their arteries as fast as possible, ideally within a couple of hours of having a stroke, and no later than 4.5 hours on from the event," Professor Jackson says.
Sadly, less than one in 10 people with stroke get the therapy. "We're not getting people to hospital soon enough, within this very narrow window when the medication is effective," he says.
The team believes inflammation may play a role in this narrow success window, which means the new blocking therapy may allow the medication to be given later than before.
This research represents the culmination of an international multidisciplinary team effort involving scientists at the Heart Research Institute, Monash University and The Scripps Research Institute, California, USA.
"This is an exciting area of research as new medicines are urgently required to improve patient outcomes with heart disease and stroke,’ Professor Jackson says.
With funding and clinical trial approval, the new brain injury blocker could be available within five years, he says.