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Even with rapid action, strokes can lead to lasting brain damage. So researchers are developing new techniques like freezing brains to buy time and using using parts of pork bladders to regrow brain tissue.

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When it comes to strokes, doctors often say “time is brain,” meaning that the more time that passes before a stroke is identified and treated, the more damage it can do. Which is why medical professionals want everyone to know how to spot a stroke F.

A. S. T.

Weakness in the Face or Arm? Speech problems? Time to call 911.

But even with rapid action, there can be lasting damage. So researchers are looking for better ways to help stroke patients, and that's led to some kind of creative ideas. A stroke happens when part of the brain's blood supply is cut off.

The lack of blood flow means some of the tissue stops receiving oxygen. So it essentially suffocates and starts to die. That leads to neurological symptoms, like slurred speech and weak limbs.

And when brain cells die, losses to function can be permanent. It'd be great to just never have these things happen. Unfortunately, stopping strokes entirely isn't likely.

The trouble is, there are two main types of strokes. About 15% of strokes are hemorrhagic strokes, which is when a burst blood vessel leads to bleeding in the brain, which disrupts the normal flow of blood to the surrounding brain tissue. Most strokes, however, fall under the banner of ischemic attacks, which means a blood clot obstructs blood flow to part of the brain.

That means, to stop all strokes, you'd need to make it so people have blood vessels that never fail or clog. And that's just not really possible. So instead, scientists are looking at ways to minimize the damage strokes cause.

And they've gotten pretty creative about it. Since time is a critical factor in how much damage a stroke will do, any treatment that can buy doctors more time can help. Sadly, we have not yet figured out how to freeze time.

But doctors can do the next best thing: freeze a person's brain. It's a technique called therapeutic hypothermia. And, OK, technically, the brain is not frozen.

Using ice-cold IV drips and cold packs applied to the skin, physicians lower the patient's body temperature to around 33 to 36 degrees Celsius, a bit below the typical 36 to 37. This aims to slow down something called the ischemic cascade. See, your brain cells, like pretty much all cells in your body, prefer to make their energy-shuttling molecules with a process that requires oxygen.

When they stop receiving oxygen because their blood supply is cut off, they switch to a less efficient method in an attempt to keep up with the energy demand. Soon, though, there's just not enough energy to go around, and everything starts to fall apart. Before you know it, the cell is dead.

The longer the tissue lacks oxygen, the more cells will die, and the larger the damaged area becomes. But, since all of this stems from those cells needing energy, if you lower their energy needs, they can last longer before they crash. It's kind of like how you can keep your phone running longer if you dim the screen and turn on airplane mode.

And that's what therapeutic hypothermia seems to do, it slows all sorts of processes in cells, thereby reducing their energy needs. Studies have found that for every degree you reduce a person's core body temperature, the rate at which their cells use energy decreases by up to 5%. That buys more time to treat the clot or bleed.

And, once the cause of the stroke is fixed, the patient can be warmed up gradually, over the course of many hours, to avoid the complications that come with a rapid increase in body temperature. But while therapeutic hypothermia can help prevent brain damage from occurring, it doesn't affect the damage that's already been done. And unfortunately, strokes often have lasting symptoms, because brain tissue is notoriously bad at repairing itself.

Now some scientists believe that's largely because there isn't enough structural support for the tissue that tries to grow back. Patients basically end up with small, fluid-filled cavities in their brains once the debris from the dead cells is cleared out. That's why some neuroscientists think they can give the brain a helping hand using a technique called bio-scaffolding.

A bio-scaffold is a structure that tissue can grow over, an empty frame of sorts that encourages new cell growth better than the fluid-filled cavity. One 2012 study even suggests the best material for scaffolding is… pork bladder tissue? Or what's left of it, anyway, after you remove the actual cells, what scientists call the extracellular matrix.

That's basically all the proteins, starches, and other molecules in between your cells which support them physically and biochemically. So the idea is, you plug a gap in someone's brain with the structural elements of bladder tissue and maybe add some neural stem cells to get things rolling. And voila!

But although there have been promising results in rodent models, we don't know for sure that this works in humans. And before we could start doing this in human brains, we'd need to make sure the tissue wouldn't grow back in a problematic way and that the immune system wouldn't respond unfavorably to the scaffold. There are also other ways to encourage healing, like, by injecting molecular signals for regrowth.

The thing is, it's not just neurons that need to grow back. The new tissue will also need the little blood vessels that ensure those neurons get enough oxygen and nutrients. And that's why one group investigating this kind of injection tried something called vascular endothelial growth factor, or VEGF, a substance that, among other things, encourages blood vessels to grow.

Previous research had suggested injecting VEGF into brains wasn't so great because it causes inflammation and doesn't do much in the way of repairing stroke damage. But that was when it was injected all alone. So, the research team created a water-based gel from a starch known to promote neurons to grow from stem cells and added nanoparticles that dampen inflammation.

Then, they added VEGF and injected the mix into stroke cavities in the brains of mice. And, as hoped, new blood vessels and new neurons grew into that space. The damaged areas even started working again, which didn't happen for animals that received a control gel.

Like with scaffolding, this hasn't been tried in people yet, but with such promising results, human trials might not be too far off. And these methods aren't necessarily mutually exclusive. A doctor may be able to use some combination of therapeutic hypothermia, bio-scaffolding, and injectable growth promoters to give their stroke patients the best possible outcome.

Plus, these are just a few of the promising developments from the field. Stroke treatment and rehabilitation are two massive fields of research, so doctors are bound to come up with other exciting, creative solutions. We still have a long way to go before strokes are easily treatable.

But with a little luck, approaches like these will go from theory to practice very soon. Thanks for watching this episode of SciShow Psych! If you enjoy learning about your brain and how it works, and, presumably you do because you're watching this, be sure to stick around!

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