22nd Mar 2019
22nd Mar 2019
Curated by Daniel Ojeda Juárez
Researchers have come across an unexpected discovery: a previously approved HIV drug can speed up recovery after a stroke. As the drug has already been licensed, human trials can soon reveal if it should be part of stroke rehabilitation.
In 10 seconds? Using an existing drug to block the same protein that allows HIV to infect human cells can speed up rebuilding neural connections in the brains of stroke victims. (Read the science)
Wow, how is that possible? Scientists have found that the CCR5 protein used by HIV to trick its way into human cells plays a role in our body's recovery from traumatic brain injury and even stroke. More precisely, when they switched off the gene that produces the protein, they observed faster recovery in the motor and other skills of lab mice that suffered a stroke. The drug treatment helped even when it was administered three weeks after the stroke. (Read the paper)
But how did they connect HIV to stroke? Initially, neuroscientists were looking for mutations that could improve memory and learning. They examined 148 types of mice, each lacking a specific protein. This is how they found that mice lacking CCR5 had better memory and learning abilities. CCR5 is a known target for an HIV drug that tries to prevent more cells from being infected by the virus. As researchers saw parallels between learning and memory, and how skills have to be re-learnt after a stroke, they decided to investigate. (Find out more)
So what did they find? Using the CCR5-blocking drug, maraviroc, they managed to preserve brain connections involved in chemical signalling and help surviving neurons increase connections to other brain regions. When administered 24 hours post-stroke, the treatment improved motor movement, and surprisingly, mice given the drug 3 weeks after the trauma, still showed some improvement. If the drug has a similar effect on humans, it will be the first of its kind and a huge improvement, as the current treatment only works within 4 hours after a stroke. (More on the effect of silencing CCR5)
Can we expect good news? Scientists stress that mouse experiments are not always useful for humans. But two aspects raise hope. One is that researchers have already observed stroke recovery in people lacking CCR5. Israeli teams have observed that Ashkenazi Jews have a higher proportion of individuals without this protein and they performed better in motor, sensory and cognitive skills tests that took place 6 months and a year after they suffered a stroke. (Read more CCR5 and neuronal injury)
And what's the other? Maraviroc is an already licensed, safe drug - so a clinical trial to test its usefulness in stroke can proceed very quickly. In fact, it is planned for this year! (More on current therapies)
How CCR5 got a bad rap - for a while
The CCR5 protein acquired a certain status for notoriety as it was the subject of a controversial gene editing experiment in 2018.
A researcher at Southern University of Science and Technology in China, He Jiankui had edited out CCR5 from the embryos of twin girls that were born later.
He wanted to show that with the technique he could prevent them from ever becoming infected by HIV. Lulu’s and Nana’s case caused a global outcry as this was the first case of gene-edited babies.
The Chinese authorities have placed He under police investigation and issued new rules threatening “rogue scientists” with fines and punishment.
However, researchers are now suggesting that by editing out the girls’ CCR5, the scientist has inadvertently made them smarter and better learners.