Missing a certain gene may actually be an advantage for stroke survivors, a new study suggests.
People who don’t have the CCR5 gene are able to regain cognitive and motor functions more quickly and completely after suffering a stroke, collaborating researchers at the University of California, Los Angeles and Tel Aviv University found.
CCR5 is the same gene that allows the HIV virus to enter certain cells, according to previous research.
And using an already FDA-approved drug that blocks the gene may help mild or moderately severe stroke patients to better recover from the events, the new study suggests.
For the first time, scientists have linked a gene – CCR5 – to stroke recovery, and found that turning it off using an existing HIV drug may ensure people recover better from brain trauma
Even a mild stroke can be debilitating, altering mobility, memory and cognitive function.
The extent of a stroke’s damage varies wildly from person to person, and scientists may at last have some clues as to why.
A stroke occurs when oxygen is temporary cut off from the brain.
Without oxygen, brain cells begin to die off, and the neural connections those cells were involved in are lost with them.
But the brain is a remarkably malleable, reparable organ.
Its ability to form new connections between neurons is called neuroplasticity, and how ‘flexible’ the brain is at any given time is influenced by both our DNA and day-to-day factors like our stress levels.
The UCLA team discovered that the CCR5 gene is intimately involved in determining how well the brain can recover after a stroke.
The expression of this gene seems to cause all kind of problems in the body and brain.
CCR5 not lets the HIV virus sneak into certain cells, its expression also seems to inhibit neuroplasticity and, therefore, recovery from traumatic brain events like stroke.
In the early 2000s, scientists developed a drug, called maraviroc, that acts as an antiretroviral for HIV by blocking CCR5. The drug turns of the gene, which keeps the door from being opened up to HIV.
After observing years ago that suppressing the gene improved memory as well as fighting off HIV, the UCLA researchers then worked with Hebrew University scientists to test the drug’s effects on mice that had had strokes.
Those that they treated with the gene-muting drug recovered far better from mild or moderate strokes, and scans of their brains showed significantly less scarring after the events.
To take their research still one step further, the UCLA wanted to see if the pattern of better recovery held true among human populations that don’t have CCR5.
As it happens, Ashkenazi Jews often have the inherited CCR5 deletion, and, as it happened, researchers at Tel Aviv University happened to be studying a group of nearly 450 stroke patients.
The collaborating researchers tested the cohort’s blood, and found that, just as the UCLA team suspected, those who were missing CCR5 did much better after suffering mild or moderate strokes.
Taken together, the facets of the research project suggests that blocking this single gene by prescribing maraviroc might be a huge boost to stroke recovery.
‘The big question left to answer was whether eliminating CCR5 would produce the same results in people,’ said lead study author Dr Thomas Carmichael, lead study author and neurology department chair at UCLA.
‘This is the first time that a human gene has been linked to a better recovery from stroke,’ said Dr Carmichael.
‘Our discovery offers exciting potential for improving patients’ health and enhancing their quality of life.’
CCR5 is a hot-topic gene at the moment, and was involved in one of the most controversial medical developments of the last year.
In November, Chinese scientists claimed that healthy twin girls had been born after they had edited their genomes as embryos – a world first.
The gene they edited was CCR5, deleting it to protect the girls form inheriting their father’s HIV.
The procedure was highly controversial, in part because experts argued that simpler treatment, like maraviroc, could have accomplished the same results.