How Keeping Brain Cells Alive May Help You Fully Recover from Stroke
New work shows that there are little subcellular packages that can deliver powerful healing to brain cells.
Do you know anyone who has suffered from stroke?
A Stroke can be devastating because of the dramatic physical and emotional effects that can result from you or your loved ones experiencing one.
Stroke is usually associated with elderly men. But women get strokes, too.
Scientists at the University of Georgia have just published an article showing that delivering little fluid filled packages called exosomes into the brains of pigs can lead to their complete recovery from a stroke.
Pigs were bred to have the same pattern of stroke degeneration and killing of brain cells as humans undergoing stroke. When the animals were treated with exosomes, they exhibited a full recovery from the stroke as shown in brain imaging data.
Senior study investigator Steven Stice, PhD, a professor in UGA’s College of Agricultural and Environmental Sciences remarked:
“It was eye-opening and unexpected that you would see such a benefit after having had such a severe stroke…the most formidable discovery was that one could recover and do so well after the exosome treatment.”
So what are these remarkable little packages called exosomes?
Welcome to today’s mini biology lesson 😄
Briefly, exosomes are made by most of our cells and the cells of other higher forms of life. Inside the cell are certain membrane structures called endosomes. The endosomes can take small amounts of different cell components and package them inside membranes for secretion outside the cell. Different cells will make exosomes containing different chemical and molecular constituents. A look at the figure below gives you the basic idea. Don’t worry about all the other details.
Techno geek note: The prefix "endo" means inside or internal and the prefix "exo" means outside or external. The suffix "some" is derived from Greek σῶμα söma, which means body.
Exosomes are naturally made by brain stem cells and have long been known to be powerful mediators of cell-to-cell communications. Cells that receive signals from them are known to alter their behaviour in various ways.
During a stroke, brain cells die. Sometimes in the multiple of millions, depending on the type and severity of the stroke. At the site of the stroke untreated nearby cells become starved for oxygen which may lead to their rapid death which then sends death signals to millions of other cells which could compromise their ability to function and/or result in their death.
This can result in a shift of the brain to the left or right of its center line, the valley between the left and right sides of the brain. This is technically called a midline shift or MLS. Brain lesions such as those created during a stroke or from tumours induce inflammation or pressure to build up which causes the brain to shift.
This shift is easily detected in magnetic resonance imaging or MRI, scans.
The pigs that were given exosomes intravenously were able to halt this process of cell death which aided in more complete and rapid recovery.
So the Stice lab wondered, could they look at the MLS and use it to tell how severe the stroke was and be able to predict how effective the recovery was and also what aspects of complete recovery might be permanently affected?
To test this they measured the MLS of both untreated and exosome-treated pigs before and after stroke. They also tested gait, cadence, walking speed, and stride length at one day and 84 days after in both treated and untreated animals.
They discovered “significant correlations” between MLS and some of these physical abilities.
That term, significant correlations, is a tricky one! Basically, it means, “things are looking pretty darn good but we don’t know for sure”!
And that means that it’s still too soon to begin treating humans with exosomes. That may happen in the future after many clinical trials have been performed and we can show that human exosome treatment is both safe and effective.
In the interim, though, what they hope these and further experiments will give them is a tool that an emergency room clinician can use to diagnose and give specific, personalized predictions to patients that have just had a stroke.
The ideal scenario would be: a patient is brought to emergency with a stroke, they immediately do an MRI to assess the patient’s MLS and then they can tell the person that they’ll be mostly recovered in a few months but may have problems with their ability to walk so let’s set up an appointment with a specialist that can help you with that.
In science we mostly move forward, or progress, in tiny steps. Big steps happen now and again and sometimes we don’t even know when a big step has been taken. But that shouldn’t stop us from celebrating steps like this one.
If you’re a person suffering from a stroke, or know someone who is suffering from or who suffered from a stroke, this is not such a small step! And it looks towards a much brighter future for those of us who may experience stroke in the future, whether it’s from the viewpoint of a caring family member or from being the actual stroke victim.
And on that positive note, I think I’ll stop.
Until next time,
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