New hope for after-stroke treatment

But the message is not crystal-clear

Researchers from Stanford, California, have found that a protein well-known to be a part of our eyes might provide protection after stroke. The protein is called crystallin and is called so because it was discovered as a protein that supports our eye lens structure and is responsible for its optical properties. It was later found to be produced by other tissues of the body including many kinds of brain cells. Ahmet Arac and colleagues set out to investigate if the protein might have any function in the aftermath of a brain stroke.
When mice suffered stroke, the researchers discovered that animals that were not able to produce crystallin, showed larger area of brain injury and the stroke itself affected their motor functions to a much greater extent. When they looked closer at the lesions, they found there was much more inflammation going on in the animals without crystallin. Even though inflammation is there to fight damage, when excessive, can cause even more of it. To make sure that it is crystallin that makes the difference, the scientists went on to inject it into the mice that couldn’t produce it themselves. And as expected, this procedure made the brain lesions size comparable to that seen in mice which can readily produce their own crystallin. But then they thought – that’s not actually a real-life situation, because all humans produce crystallin, so we could never use it to help people who don’t. So they decided to check if they will see any difference after injecting crystallin to mice that can produce their own. And indeed – when the protein was given to these animals after the stroke their lesion area was much smaller than when they received no treatment. And importantly, this effect was apparent even when they waited with the injections until 12 hours after the injury. Now that seems to be more applicable in real-life situations, especially when something stands in the way of immediate treatment of a stroke victim. And apart from experiments in mice, the researchers also asked whether crystallin might be important in human strokes. They tested the blood of several patients who have suffered stroke and discovered that indeed the protein levels are higher than in healthy people, which might suggest that human body after stroke also uses that protein to minimise the damage caused.
So is this discovery a new hope for stroke patients? Might very well be. The research quite convincingly shows that crystallin plays an important part in minimising the damage done to the brain following a stroke, by alleviating the severity of the inflammation. It even shows that injecting crystallin as a post-stroke intervention can do the trick. But what I found missing from these studies, is looking at how the animals did in terms of motor functions after they were given the protein, as the authors did not show that. Obviously having less inflammation in your brain is an encouraging result, but is it still any good if there is no difference in the damage caused? Hopefully they will address this issue soon and a new treatment for stroke patients might soon be under way.


Systemic augmentation of αB-crystallin provides therapeutic benefit twelve hours post-stroke onset via immune modulation