A pill for stroke victims?

It’s long been believed that if you have a stroke or other brain injury, your brain never fully recovers. A stroke disrupts a vast network of neurons that exchange messages with far-off regions. After a stroke, patients usually recover some functionality, but few achieve close to a full recovery. At some point, the brain decides it’s done healing. Dr. S. Thomas Carmichael, head of neurology at the Geffen School of Medicine, finds that a patient’s brain would heal and adapt somewhat, but “it just doesn’t get very far.”

Scientists studying “smart” mice discovered that they lacked a gene that affects a particular receptor in the brain—the one that causes the brain to hold itself back. Mice lacking this gene have an enhanced ability to learn and remember, and they recover faster and more completely from a stroke than mice who have the gene.

With this discovery in mind, researchers looked for humans who had the same mutation. They found a neurologist at Tel Aviv University in Israel who was tracking a cohort of 600 stroke patients to see which ones developed dementia. It turned out that some people in her study did have the same genetic mutation as the smart mice and that they did have better scores on language, memory, and attention. The first gene associated with stroke recovery has been discovered.

The team that had been studying the mice had also found a drug, Maraviroc—a little-known H.I.V. treatment that, as a “side effect,” boosted neuroplasticity after brain injury. That drug, which mimics the gene mutation, is now being administered to stroke victims in a clinical trial. It’s not a perfect drug, but it will lay the groundwork for future therapies by deepening the understanding of the brain’s recovery system.

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