Research Matters: Stem Cell Reality Check

By | 2018-01-03T14:01:18+00:00 January 2nd, 2018|
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Kate WilletteSometimes I think of the paralysis research world as a sort of Pentagon. It’s a monster-sized building labeled Spinal Cord Injury Repair, and nobody can get in without a lot of specialized credentials. Like the actual Pentagon, the one in my imagination has several wings, one for each of the main research thrusts. Today we’re outside the wing with the gold-plated sign that says Stem Cell Research, standing in front of a small window with the blinds pulled down. Someone inside has tilted the blinds to let us get a peek at what’s happening inside the room.

Unfortunately, we still can’t look directly inside. Instead, it’s as if we’re looking into a sort of funhouse distorting mirror. Things in this mirror are not as close or as large as they seem. Usually this blinds-tilting moment happens in the form of a news story, or a video someone shares to your social media feed. Today’s example is a 74-second video with an impressive headline:

Paralysis Treatment with Stem Cells: Paralyzed patient treated with stem cells regains upper body movement.

That was posted on August 16, 2017, through an online magazine called The Science Explorer. By the end of the month it had more than 440,000 views and 7,551 shares in social media. It came with a brief video showing a young man named Kris Boesen using his iPhone, opening a bottle of Gatorade, lifting weights over his head, and managing a coffee cup. Boesen had a high, motor-complete cervical injury, so all of that would be unusual, to put it mildly.

The video itself had hit the internet a week earlier as part of a press release offered to the public by a company called Asterias. I was one of the thousands of people who got tagged by friends who thought I’d be interested in that news. It made sense; my husband has a C6 injury, and I’ve made it my job to follow any science that promises to help him.

So, what should our community make of this video?

Quad Kris Boesen demonstrated manual dexterity in a video that went viral.

Quad Kris Boesen demonstrated manual dexterity in a video that went viral.

First, notice that it’s in a press release. This is a company offering its best version of what it’s doing to the press — the video is advertising.

Second, what’s the company’s reason for trying to draw attention to itself in this way? This is a product in development, meaning it’s not ready for the public yet. They’re not selling it, at least not to us. The company’s target for the announcement is not you or me, it’s investors.

Third, what are they selling? At this point, Asterias is selling the potential of the eventual product to investors. That’s the reason for the press  release. They want people with money to notice them and become convinced that investing now is a good idea. I can’t say how glad I am to see them doing this; I’ve met some of the scientists at Asterias, and they’re very disciplined, ambitious people. This press release means they believe they have something that will be of great value.

So, here’s what our partial and distorted view into the Stem Cell Wing shows us: Asterias has created some kind of cell-based product aimed at our community. They’re testing to find out whether or not their designer cells do no harm and improve life with SCI in some measurable way. They’re pleased with the results so far. They’ve named the test they’re conducting SCIStar.

Just what are these designer cells?

Cell Replacement Strategies: A Primer

There are three main kinds of cells in a working spinal cord. You need all three, because they have to work together, and if you lose some of them to injury, one of the ways to repair that loss seems obvious: get some replacement cells. This is harder than it sounds, because we don’t have big stashes of these three kinds lying around, and we don’t have bodies that can build them out of spare parts. If the cells are going to be replaced, we’ll need a source. The three kinds of cells are, in very rough lay terms:

Message carriers (neurons). A message-carrying cell does its job by sending chemical/electrical signals down gossamer strands called axons. Each message-carrying cell has just one axon for sending information, along with lots of little feelers (dendrites) for taking in information from other axons. You have about 86 billion of these cells in your brain, and another 15 billion in your cord, give or take.

Wrappers (oligodendrocytes). A wrapper cell’s job is to produce this stuff called myelin and get it wrapped around every single axon. Without the wrapping, axons don’t work right. The messages aren’t sent, or are sent distorted, or aren’t received, or travel too slowly. This means that even if you have plenty of perfectly good messenger cells, your cord still isn’t going to work properly.

Management and Maintenance (astrocytes). These guys mainly do the care and feeding and cleanup after their two partners. They’re like facilitators at a giant meeting, making sure the air-conditioning works, everybody has enough to eat and there’s plenty of toilet paper. They’re essential.

So what is the SCIStar trial all about?

It’s about replacing lost cells, and the cells they’re trying to replace are the wrapper cells. Their plan is to put what you might think of as infant wrapper cells (called oligodendrocyte precursors) into damaged cords. The infant wrapper cells will then mature into adult cells, which will produce enough myelin to wrap up lots of healthy-but-nonproductive axons that were left naked by the injury. In theory, what happens next is that the axons get back to work. Fingers move. Numb spots wake up. Boom, sensation and function. That’s the agenda.

Where do they get these wrapper cells?

That’s a long, involved story that goes all the way back to the late ’90s. The infant wrapper cells are all derived from a single donated human blastocyst that has grown from a fertilized egg left over and donated after a fertility treatment. That means the cells used in this trial started out as stem cells, which means that they can — under the right conditions — be kept alive and reproducing indefinitely.

In 2005 some scientists in California published a paper showing that they’d succeeded in using those stem cells to create a healthy line of infant wrapper cells. It was quite a trick, and the fact that those cells helped paralyzed rats to regain function is one of the memorable moments in SCI history. That same line of infant wrapper cells is the product that Asterias is using today — it’s what they put into Boesen’s neck.

The 2005 paper also holds the key to another big question for us: Will this ever help me or someone I love who has a spinal cord injury?

The answer is, not directly. If you read the fine print at the Asterias website, one question that pops out is who exactly is a candidate for their study. The answer? People with injuries that are between two and six weeks old. This is the range they’re calling “sub-acute,” and the reason for that particular restriction is that when those scientists back in California tried putting their cells into rats with longer-term injuries (usually called “chronic SCI”), the rats didn’t get better. Some of them actually got worse.

This particular wrapper cell replacement project, then, is only aimed at people less than two months post-injury. So when your friends link you to the next story of how Asterias is on the brink of solving spinal cord injury with stem cells, you can tell them that this will, maybe someday, be a therapy for those unlucky people whose injuries are still in the future. May it be so.

In the meantime, there are other projects aimed at people whose injuries are much, much older. More on that another time.