A Human Trial For CRISPR Gene Therapy
This week, researchers announced that they have started a clinical trial of a treatment that uses the CRISPR gene-editing technique on live cells inside a human eye. The researchers hope that CRISPR will allow them to slice out a mutated section of genetic code responsible for one variant of a condition called Leber congenital amaurosis, a disorder in the retina that causes severe visual impairment from infancy.
It will be several weeks before doctors at the Casey Eye Institute in Portland, Oregon know whether the technique has had an effect on this patient. They hope to treat a total of 18 patients over the course of the trial, which is being sponsored by Editas Medicine and Allergan.
Science Friday’s director Charles Bergquist joins Ira to talk about the trial and other stories from the week in science, including an orbital service call for an aging satellite, a study on the effects of climate change on the world’s sandy beaches, and the discovery that a bird called a kea may be able to understand and act on probability.
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As Science Friday’s director, Charles Bergquist channels the chaos of a live production studio into something sounding like a radio program. Favorite topics include planetary sciences, chemistry, materials, and shiny things with blinking lights.
IRA FLATOW: This is “Science Friday.” I’m Ira Flatow. A bit later in the hour we’ll have an update on the coronavirus outbreak, and talk about how geneticists are helping to monitor its spread. But first, this week, doctors started the first human trial of a gene therapy involving the gene editing technique CRISPR, hoping to combat a form of congenital blindness. Here to tell more about that and other selected short subjects in science is our own Charles Bergquist. Welcome back, Charles.
CHARLES BERGQUIST: Hi, Ira.
IRA FLATOW: Let’s talk about this.
CHARLES BERGQUIST: Yeah, so this week, the researchers announced that they’ve started a clinical trial of a treatment that would use the CRISPR gene editing technique on live cells inside a human eye. They’re trying to treat one variant of a condition called Leber congenital amaurosis. It’s a retinal disorder that causes severe visual impairment, from infancy basically.
And so they’re injecting this treatment under the retina, inside a living person’s eye.
IRA FLATOW: And why use CRISPR for this?
CHARLES BERGQUIST: So standard gene therapy, you’d try and sort of swap out the gene by ferrying a replacement gene inside the cell. The messed up gene in this case is too big to fit in that viral payload. So instead what they’re trying to do is use the CRISPR technique just to sort of delete the problem section of the gene, in the hopes that it will allow the cells to function normally.
IRA FLATOW: So what kind of frame are we talking about?
CHARLES BERGQUIST: So this is a phase I/II trial. They’re testing both safety and efficacy here. In animal tests, they were able to correct about half of the cells in the eye. It’ll be a few weeks to maybe a month before they find out whether this particular patient has any benefit from treatment.
IRA FLATOW: Let’s move on to the continuing bad news about climate change, the outlook for the world’s sandy beaches disappearing.
CHARLES BERGQUIST: Yeah, so this is a study that was published this week in the journal Nature Climate Change. And researchers used satellite images collected over a period of 30 years to track the progression of sandy beaches around the world. And then they used that data to simulate what might happen with global warming, and rising sea levels, more erosion, bigger storms, things like that.
IRA FLATOW: And they found that, across the world, we’re losing sand on those beaches.
CHARLES BERGQUIST: You’re losing a lot of sand. They’re estimating that in maybe 30 years or so, erosion will have destroyed over 22,000 miles of sandy coastlines around the world. Different places around the world were hit differently in their simulations. Australia was one of the worst. The United States would probably lose thousands of miles of beach according to the study.
IRA FLATOW: And of course, is there anything you can do about it?
CHARLES BERGQUIST: You know, it’s a good news/bad news situation here. The bad news is that they’re saying that this is a conservative estimate. They think it could possibly be worse than they are predicting. But they also say that if greenhouse gas emissions are moderately controlled, it might be able to prevent some of this effect.
IRA FLATOW: Let’s look up into space. I know there’s a story that you really were talking about earlier this weekend, a satellite servicing mission?
CHARLES BERGQUIST: I know, this is just such a geeky, fun story. So space junk is a big deal, right. And when you’ve got an aging, broken satellite you’ve basically got two options of what to do with it. You can either deorbit it, as they say, and let it burn up in the atmosphere, or you can push it up into this graveyard orbit, and let it rot up there. Last week, Northrop Grumman decided to try something else. And they launched a satellite that basically came up to an aging communications satellite called Intelsat 901, and latched on to it, and now is going to be serving as a backup propulsion system for that satellite.
IRA FLATOW: You mean it’s like a tow truck sort of thing?
CHARLES BERGQUIST: Yeah, tugboat, maybe. It’s that sort of–
IRA FLATOW: How would that work?
CHARLES BERGQUIST: So the satellite wasn’t designed to be docked with. So the new servicing satellite kind of came up behind it, and inserted itself into the thruster nozzle, basically, of the old satellite, and grabbed on there. And they’re now using the motors and thrusters from the new satellite to push the other one around like a tugboat.
IRA FLATOW: So it’s going to stay with it while it’s in the new orbit?
CHARLES BERGQUIST: Yeah, so the contract is for five years. So it will ferry this other satellite around for five years. And then the plan is that it will shove it up into the graveyard orbit. But the cool part is the servicing satellite can then detach, find another satellite to help out. And they’re saying that they can keep using it for another 15 years or so.
IRA FLATOW: Wow, there’s a whole new business with satellites.
CHARLES BERGQUIST: That’s right, satellite repair.
IRA FLATOW: Satellite repair. In other space news, just released yesterday, right, a new name for the Mars Rover 2020.
CHARLES BERGQUIST: Right. It had been going by the name, Mars 2020 Rover, which is sort of dull. But they officially now have named it Perseverance. It was suggested by Alex Mather, a seventh grade student from Virginia.
IRA FLATOW: There was a contest, right?
CHARLES BERGQUIST: Yeah, it was a nationwide contest, and people sent in lots of names. There were some that were more creative than others, but they went with Perseverance.
IRA FLATOW: That’s a good name.
CHARLES BERGQUIST: Yeah.
IRA FLATOW: I like that. They like these multiple-syllable names, too. And what’s its mission? When’s it going up? What’s it going to do?
CHARLES BERGQUIST: So it’s supposed to be launching late July, early August of this year, arrive in Mars next February. And once it’s on Mars, the Rover is going to be looking for what they call biosignatures, signs that maybe, once upon a time, there was living material in some of these rocks. They’re looking specifically in areas where they think there might have been water and decent conditions for life.
IRA FLATOW: And it will be able to collect samples, actually chip off pieces?
CHARLES BERGQUIST: It will have a container that it can, if it finds something super cool that it wants to save for later, it can stow it. And they’re talking about maybe some kind of sample return mission down the road. We’ll see.
IRA FLATOW: That’d be great, actually just to go there, and find this rover, and pick up the stuff. Finally, there’s news about a New Zealand parrot that can understand probability.
CHARLES BERGQUIST: Right. So this is a paper that was published this week in the journal, Nature Communications. And researchers in New Zealand, were working with a kind of parrot called a kea. And they say that this bird seems to have an ability to understand probability, which is something that normally you would only attribute to humans or other great apes.
What they did is first they trained the parrot that if it got a black poker chip, that was good. It could trade that for a treat. And then they showed it two jars mixed filled with a mix of orange and black chips. And the researcher would reach into the jar, and fiddle around, and pull out a chip from each jar, and offer closed hands to the parrot. And the parrot got to choose which hand is more likely to have the treat chip in it.
And they found that the parrot would consistently pick the more probable hand to receive the treat.
IRA FLATOW: Why? How did it know what to choose?
CHARLES BERGQUIST: So they tried a couple different things– mixing the numbers of the different color chips within the jar, the blend. So they’re fairly confident that it’s not looking at just, oh, that jar has more black chips. It’s actually somehow being able to calculate, I’ve got a better chance at getting my treat chip out of the jar on the left.
IRA FLATOW: Does it watch what the preference of the scientist is?
CHARLES BERGQUIST: Yeah, another fun part of the study was they had some researchers who were biased. And they they’d made a big show of digging around in the jar, and looking, oh, I’m going to find the right chip here. And the parrots learned that, if Bob picks it, I’m more likely to get the treat. And so they would go with him.
So they’re saying it’s a sign that there’s more complicated things going on in their not-bird brain.
IRA FLATOW: Not bird. Thank you, Charles. Charles Bergquist, “Science Friday”‘s director.