What Greenland Sharks Are Teaching Us About Aging Eyes - podcast episode cover

What Greenland Sharks Are Teaching Us About Aging Eyes

Jan 15, 202618 minEp. 1211
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Summary

Discover the secrets behind the Greenland shark's remarkably healthy eyes, which show no signs of aging despite their 400-year lifespan, and learn how their efficient DNA repair mechanisms could offer clues for preserving human eyesight. The episode also marvels at the James Webb Space Telescope's incredibly precise mirrors, discussing the advanced engineering required for deep space observation and an unexpected medical application developed from its technology. It concludes with a reflection on how scientific exploration can inspire awe and connect with broader human and spiritual questions.

Episode description

As we age, our vision gets blurrier, we form cataracts, and we have a higher risk of glaucoma. But Greenland sharks live for hundreds of years and still maintain healthy, functional eyeballs. So what gives?

Host Ira Flatow talks with molecular biologist Dorota Skowronska-Krawczyk, who studies the mechanisms of aging, about what we can learn from these fishy eyeballs and how it could help us.

Plus, listener Leon called us with a question: Is it true that the James Webb Space Telescope’s gold-plated mirror is so perfectly flat that if it were the size of the United States, the highest bump would be the size of a baseball? Not quite. Host Flora Lichtman discusses this feat of engineering with JWST project scientist Macarena Garcia Marin.

Guests:

Dr. Dorota Skowronska-Krawczyk is a molecular biologist and associate professor at the University of California, Irvine. She studies the mechanisms of aging.
Dr. Macarena Garcia Marin is a project scientist for the James Webb Space Telescope at the Space Telescope and Science Institute in Baltimore, Maryland.

Transcripts for each episode are available within 1-3 days at sciencefriday.com.

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Transcript

Intro / Opening

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Greenland Sharks: Age-Defying Eyes

Eyeballs. As we age, all sorts of things can go awry in our eyes. Our vision gets blurry, cataracts may make our eyes cloudy, and we're more at risk for diseases like glaucoma. So how do we keep our eyes healthy for longer? According to new research published in Nature Communications, one clue may lie in the eyeballs of, you're never going to guess this, the eyeballs of Greenland sharks. These sharks can survive for more than 400 years, and because they live for so long,

and their eyeballs looked glazed over, scientists thought they were basically blind. That is until this new study found that the shark's eyes are healthier than we originally thought. So... How can Greenland sharks maintain their healthy eyes for so long? And can it tell us anything about preserving our own eyesight?

Joining me is the study author, Dr. Dorota Skowranska-Krawczyk, Associate Professor at the University of California, Irvine, who studies the mechanisms of aging. Welcome to Science Friday. Hello. Thank you for having me. Nice to have you. So what is it about Greenland sharks that caught your eye, so to speak? Yes. There was a study in 2016 in Science, so a very good journal, talking about how long a shark can live. And they found that

These sharks can live, as you said, over 400 years. But at the same time, they released a lot of movies. And the movies were really cool. I mean, you know, they were like people swimming along the... shark and filming them and what i noticed is that the sharks are observing the swimmers so they're looking back at the swimmers who are looking at them is what you're saying exactly they were following them with their eyes

Well, that was just first observation. So I was really, I mean, for me as a eye lover, it was very interesting and so on. And then I read the paper carefully and I realized that there is a strong assumption that those animals do not see. That was weird for me because they were definitely following the light, especially. Your aha moment there. Yeah, there was...

Surprising. And then the occasion came when we realized that we can actually contact the scientists there and ask if they still have some leftover eyeballs from their studies because they... collected some eyeballs exactly for the carbon dating, which they did on lens.

So what did you do, just order up a box of shark eyeballs here? Something like this. Well, of course, we wrote to them a nice message and asked if they are interested in this collaboration. And they said, yes, sure, we can send you. some ice we have in freezer, but we can also collect some more ice during our next trip. Wow. That was amazing. So please, describe... What these eyeballs look like for me. Spare no details here. I want to know exactly. Well, they are quite slimy.

They are quite slimy. So when you get them, they are frozen, usually. And first of all, they are the size of the, let's say, small apple or big plum, you know? Wow. So they are pretty big. And then when we get them frozen, we don't want to lose the specimen. So what we do, we actually cut them with a little thin saw in half. I'm cringing. I'm cringing.

I know it sounds like that, but, you know, we don't want to spare material. Those animals are living so long, and we want to be sure we study everything we can with the material we have. So what's it like once you cut through it? What's it like to do that? Well, it's just, it's like ice, right? It's frozen, so it's like cutting through ice. But what is really amazing when you open, you just see cross section, you know, like...

through the eye and see how beautiful, how big it is and also how protected it is from the pressure. There is a very thick walls around so the eyes not collapse when they are deep in the sea.

this is just already you know like amazing you just already see that there are adaptations to how they live and where they live so it is a low light detecting so there's no really high resolution but they definitely see shapes passing by a light passing by and of course probably see if that's big small and so on so on

And of course, with these sharks living up to 400 years, I would expect that when you cut open the eye, you might see aged things like we have, like cataracts and signs of aging. But you didn't see that, did you? So that's the surprising part. There is no signs of the deposits behind the retina. There is no signs of some degeneration of the part of it, some cells disappearing. Everything looks very organized.

and ready to go, ready to work. As opposed to that happening in humans. Yes, yes. As we get older. Exactly. When you start to look at the human eyeballs, which we fortunately receive from donors. We can see already like around 40, 50 years old donors. We start to see some deposits, some debris, some things in the eye that we can presume.

They were already disturbing a little bit vision. But then with 60, 70 years old eyeballs, now we start to see plethora of different problems. So what is it about aging that our eyes fall apart?

Molecular Secrets of Vision Longevity

as we get older. What's going on there? I don't want to be pessimist, but actually we all fall apart. Everything falls apart, not just your eyes. Not just our eyes. Our eyes seem to... actually work pretty well for a long time and they have really a lot of mechanisms to resist the stress but what What seems to happen is that our eyes are exposed to many different small stresses, impacts and challenges through the...

life and they always have to repair themselves so there's always a little bit damage repair damage repair but you know if you have it so often sometimes the repair will not be perfect right or sometimes the mechanism of repair is not efficient in a given type of damage. So that's why with time, you know, the system is less and less resilient or more and more susceptible to next stress. And this is how it happens, you know, with time. Right, right.

Tissue goes bad. Tell me about it. I'm a direct witness to that. Well, what is it? I guess this is what you would like to know. What is it about the Greenland sharks that...

They can prevent all of this. Is it something genetic, do you think? So, yes. So there are two things that we think happen. First of all, the environment is... really cold so it slows down metabolism but then we looked into the more into molecular biology of these eyeballs and we realized that at the molecular level they seem to have very efficient highly expressed or highly present DNA repair mechanism, which means there is a push to keep this vision healthy longer.

Do we have the same gene mechanism that maybe is not expressed? That's actually a beautiful question. We have exact same mechanism, we have exact same genes, but maybe they are not expressed highly enough. So one of those genes that we've shown, we have studied a little bit before. So we know already that this mechanism is crucial, but now we have a proof that if you actually turn it up, it may be protective.

So what we need to do is figure out how to hack the Greenland shark's eye-saving method and its genetics and possibly use it for a treatment for us? That would be the simplest. The translation, right, of the findings, and obviously it sounds like that. We have to test it very much. But I do think that if we can increase the efficiency of the DNA repair mechanism, we actually may.

be able to protect vision longer. So now we started many different experiments to think about it creatively, how we could really bring it to human. Where do you go from here? Yeah, thank you for that question. So what our laboratory is interested in is to really use that knowledge about the DNA damage repair mechanism and how it's boosted in the shark eye.

to try to understand whether we can do the same first in mammals, like in mouse, and then hopefully we can translate it nicely to the human eye. We just need to think about the ways either through small molecules or maybe even gene therapy to bring this to human. And that's where you come full circle because you're a molecular biologist.

Yes, this is how we work. Well, I'm glad you've shared that with us. Thank you for taking time to be with us today. Thank you. Thank you for asking those great questions and having me share my love. Dr. Dorota Skowranska-Kravchik, Associate Professor at the University of California, Irvine, who studies the mechanisms of aging.

Coming up after the break, a different kind of eye. This one is the eye in the sky that's changing our understanding of the universe. Of course, I'm talking about the James Webb Space Telescope. Stick around. Hey, it's Flora. Speaking of remarkable eyes.

James Webb Telescope: Engineering Wonders

One of you dear listeners called us with questions about the biggest eye in the sky, the James Webb Space Telescope, and what kind of technology had to be invented to see farther back in time than ever before. And we live to serve. So here to see that we get some answers is the James Webb Space Telescope project scientist, Dr. Macarena Garcia-Marin. Welcome back, Macarena, and thanks for doing this. Thank you so much for having me, Flora. It's lovely to be back.

Let me start by introducing you to our listener who called with this question. Hi, my name is Leon and I'm from Kennewick, Washington. Leon's 18 years old. So I'm just finishing up high school, but I'm taking classes at... the local community college and then i'll i'll be going to university after i serve a mission for two years for my church and leon's

into space and he's into James Webb and he heard this thing about the James Webb Space Telescope that caught his ear. I heard once that the gold-plated mirrors on the James Webb Space Telescope have remarkably small imperfections. The analogy I heard was that if it were the size of the United States, the highest bump would be the size of a baseball. Macarena, that seems wild to me. Is that true?

It's actually not quite true because it is better than a baseball. Really? Yeah, really. And I think Liam is referring to those tiny bumps, imperfections. You know, they are there and you cannot do anything about them. And those would be, give or take, 30 percent smaller than a baseball if a mirror would be the size of the United States. We're in golf ball territory. Oh, yeah.

That's amazing. I mean, why do you need such a perfectly flat mirror? Well, because when you want to observe the very first galaxies that were created in the universe or when you want to observe nearby objects but with a really exquisite detail you do need that size and you do need that perfection otherwise things will be blurry. For sharpness, for acuity. It is sharpness and acuity. Okay.

Let's get to Lian's other question. Here's what he wants to know. My question is what the biggest hurdles were in terms of what technology they needed to develop. how they got past those and how they figured out solutions to their most complex problems. What were the biggest challenges? Are there things that still haunt you? No, because it's going so well. Well, because he's interested on the mirrors. There were many technologies developed, the manufacturing of the mirrors.

was fresh and new, but specifically the polishing of the mirrors required new technologies and the measurement of those imperfections required development of new techniques. And this is because when you build one of these telescopes, they are a one-off. So you really have to do new things to make it as perfect as possible.

So what did you have to develop to make sure it was as flat as it was? There is a lot when it comes to building this telescope of processes and engineering. So in this case would be, first of all, select the right material. Make sure the material is going to behave well when it gets really, really cold because it's in a space and it will be very cold. But also make sure that the polishing, they are made out of beryllium and that they have to be polished to perfection.

For instance, there was a development of a technique to measure those tiny bumps, to measure them very precisely to make sure that it was as flat as possible. And today that technique, or part of that technique, it's used... to diagnose and to really measure surfaces of eyes to make sure that they can be perhaps be used by optometrists or by doctors to do surgeries.

Oh, to see if your eye has any imperfections on it. Right. Just to measure the surface of the eye. So it is actually used in medicine, which is one of those. you know, spin-offs, as NASA calls them, technology you develop for a purpose, and then it trickles down into society. Wow, that's really cool. That's exactly what Leon was asking about. Yeah, he has really good questions.

Cosmic Awe and Human Endeavor

You know, before I hung up, I asked Leon why he was interested in space, and his answer caught me off guard. This might be an unusual answer, but I'm a deeply religious person. Science has kind of, for me, has strengthened my relationship with God. And I feel like it helps me to understand the Creator a little bit better. And so it just makes me feel...

I guess, hope and joy for something greater out there than us. Macarena, I loved this sentiment and I wondered how it would hit you. That's a lovely answer. I think when it comes to the universe and we look at any of, you know, even the night sky or any of the telescope's results, you always wonder about the big questions.

As in, where do we come from? Where are we going? What is the origin of everything? In this case, what is the origin of the universe in the Big Bang? So I think there is an interplay that is very clear there. Yeah, and there's awesomeness in both fields, right? And I mean that in the, you know, the true sense of the word, that there's awe. Yeah, there is absolute awe. And think of the big one.

That particular moment, which is the creation of our universe. So we can study the universe afterwards, but it can also be... from a religious perspective as the moment of creation. So I think there's a lot to think about that. Leon had one more thing to tell you, Macarena. What you've done is super awesome. And thank you for what you've done for science and exploring space. That's fantastic. And thank you to Liam. But this is, of course, the effort of thousands and thousands of people.

It takes a village. And none of this happened by chance. These were very well planned and thought of. engineering the science and science objectives and really teamwork that made it happen. But thank you. And it really was my day to hear that. Thank you, Macarena. Thank you for joining us today. Thank you. Dr. Macarena-Garcia-Marine is a project scientist for JWST. And Leon, thank you for the wonderful question. This show is produced by Rasha Aridi. And if you have a question...

that you need an answer to, give us a ring, 877-4SY-FRY. Catch you tomorrow. I'm Flora Lichtman. a KFC tale in the pursuit of flavor. The Colonel despised the word empty, empty plates, empty tables, empty stomachs. That's why he made the KFC $5 bowls like the famous bowl. Creamy mashed potatoes, crispy chicken, corn, gravy, and cheese. Because the only empty the Colonel liked was when you reached the bottom of that bowl. The Colonel lived so we could chicken. Five KFC bowls for just $5 each.

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