What Greenland Sharks Are Teaching Us About Aging Eyes

IRA FLATOW: Hi. This is Science Friday. I’m Ira Flatow. Today on the show, 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 look glazed over, scientists thought they were basically blind. That is, until this new study found that the sharks’ 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 Skowronska-Krawczyk, Associate Professor at the University of California, Irvine, who studies the mechanisms of aging. Welcome to Science Friday.

DOROTA SKOWRONSKA-KRAWCZYK: Yeah, hello. Thank you for having me.

IRA FLATOW: Nice to have you. So, what is it about Greenland sharks that caught your eye, so to speak?

DOROTA SKOWRONSKA-KRAWCZYK: Yes. There was a study in 2016, in science– so a good journal– talking about how long sharks 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, they were like people swimming along the shark and filming them. And what I noticed is that the sharks are observing the swimmers.

IRA FLATOW: So they’re looking back at the swimmers, who are looking at them, is what you’re saying.

DOROTA SKOWRONSKA-KRAWCZYK: 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. And that was like a–

IRA FLATOW: Uh-huh, your a-ha moment there. Yeah.

DOROTA SKOWRONSKA-KRAWCZYK: Yeah, that 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 the lens. It’s very interesting.

IRA FLATOW: So what did you do, just order up a box of shark eyeballs here?

DOROTA SKOWRONSKA-KRAWCZYK: 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 eyes we have in freezer, but we can also collect some more eyes during our next trip. That was amazing.

IRA FLATOW: Wow. So please, describe what these eyeballs look like for me. Spare no details here. I want to know exactly.

DOROTA SKOWRONSKA-KRAWCZYK: Well, they are quite slimy. [LAUGHS] They are quite slimy. So when we get them, they are frozen and– usually. And first of all, they are size of the, let’s say, small apple or big plum. 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 the little thin saw, in half.

IRA FLATOW: I’m cringing. I’m cringing.

[LAUGHTER]

DOROTA SKOWRONSKA-KRAWCZYK: I know it sounds like that, but 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.

IRA FLATOW: So what’s it like once you get– you cut through it? What’s it like to do that?

DOROTA SKOWRONSKA-KRAWCZYK: Well, it’s like ice. It’s frozen, so it’s like cutting through ice. But what is really amazing– when you open, you just see cross-section through the eye, and then 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 eye is not collapsed when they are deep in the sea.

It’s just already 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, light passing by, and of course, probably see if there’s big, small, and so on and so on.

IRA FLATOW: 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 we have cataracts and signs of aging, but you didn’t see that, did you?

DOROTA SKOWRONSKA-KRAWCZYK: 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.

IRA FLATOW: As opposed to that happening in humans–

DOROTA SKOWRONSKA-KRAWCZYK: Yes, yes.

IRA FLATOW: –as we get older.

DOROTA SKOWRONSKA-KRAWCZYK: Exactly. When you start to look at the human eyeballs, which we fortunately received from donors, we can see already 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.

IRA FLATOW: So what is it about aging that our eyes fall apart as we get older? What’s going on there?

DOROTA SKOWRONSKA-KRAWCZYK: I don’t want to be pessimist, but actually, we all fall apart.

IRA FLATOW: [LAUGHS] Everything falls apart, not just your eyes.

DOROTA SKOWRONSKA-KRAWCZYK: Yes, 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 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 if you have it so often, sometimes that repair will not be perfect, or sometimes the mechanism of repair is not efficient in a given type of damage. So that’s why with time, the system is less and less resilient or more and more susceptible to next stress. And this is how it happens. With time, the tissue goes bad.

IRA FLATOW: [LAUGHS] Tell me about it. I’m a direct witness to that. But what is it– and I guess this is what you would like to. What is it about the Greenland sharks that they can prevent all of this? Is it something genetic, do you think?

DOROTA SKOWRONSKA-KRAWCZYK: 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.

IRA FLATOW: Yeah. Do we have the same gene mechanism that maybe is not expressed?

DOROTA SKOWRONSKA-KRAWCZYK: That’s actually a beautiful question. We have the exact same mechanism. We have exact same genes, but maybe they are not expressed highly enough. So one of those genes that we 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.

IRA FLATOW: So what we need to do is figure out how to hack the Greenland sharks’ eye-saving method and the genetics, and possibly use it for a treatment for us?

DOROTA SKOWRONSKA-KRAWCZYK: That would be the simplest translation 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.

IRA FLATOW: Where do you go from here?

DOROTA SKOWRONSKA-KRAWCZYK: Yeah, thank you for that question. So what our laboratory is interested in is to really use the 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, so 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.

IRA FLATOW: And that’s where you come full circle because you’re a molecular biologist.

DOROTA SKOWRONSKA-KRAWCZYK: Yes, this is how we work.

IRA FLATOW: [LAUGHS] Well, I’m glad you’ve shared that with us. Thank you for taking time to be with us today.

DOROTA SKOWRONSKA-KRAWCZYK: Thank you. Thank you for asking those great questions and having me share my love.

IRA FLATOW: Dr. Dorota Skowronska-Krawczyk, Associate Professor at the University of California, Irvine, who studies the mechanisms of aging.

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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.

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FLORA LICHTMAN: Hey, it’s Flora. Speaking of remarkable eyes, 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.

MACARENA GARCIA MARIN: Thank you so much for having me, Flora. It’s lovely to be back.

FLORA LICHTMAN: Let me start by introducing you to our listener who called with this question.

SPEAKER: Hi, my name is Leon, and I’m from Kennewick, Washington.

FLORA LICHTMAN: Leon’s 18 years old.

MACARENA GARCIA MARIN: So I’m just finishing up high school, but I’m taking classes at the local community college, and then I’ll be going to university after I serve a mission for two years for my church.

FLORA LICHTMAN: 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.

SPEAKER: 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.

FLORA LICHTMAN: Macarena, that seems wild to me. Is that true?

MACARENA GARCIA MARIN: It’s actually not quite true because it is better than a baseball.

[LAUGHTER]

FLORA LICHTMAN: Really?

MACARENA GARCIA MARIN: Yeah, really. And I think Leon is referring to those tiny bumps, imperfections that– they are there and you cannot do anything about them. And those could be, give or take, 30% smaller than a baseball if the mirror would be the size of the United States.

FLORA LICHTMAN: We’re in golf ball territory–

MACARENA GARCIA MARIN: Oh, yeah.

FLORA LICHTMAN: –I think.

[LAUGHTER]

That’s amazing. I mean, why do you need such a perfectly flat mirror?

MACARENA GARCIA MARIN: 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.

FLORA LICHTMAN: For sharpness, for acuity.

MACARENA GARCIA MARIN: It is sharpness and acuity.

FLORA LICHTMAN: OK, let’s get to Leon’s other question. Here’s what he wants to know.

SPEAKER: My question is what the biggest hurdles were in terms of what technology they needed to develop and how they got past those and how they figured out solutions to their most complex problems.

FLORA LICHTMAN: What were the biggest challenges? Are there things that still haunt you?

MACARENA GARCIA MARIN: No, because it’s going so well.

[LAUGHTER]

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 mirrors require new technologies. And the measurement of those imperfections require 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.

FLORA LICHTMAN: So what did you have to develop to make sure it was as flat as it was?

MACARENA GARCIA MARIN: 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 space and it will be very cold. But also, make sure that the polishing– they are made out of beryllium metal, and that they had to be polished to perfection.

So 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 ice to make sure that they can be– perhaps be used by optometrists or by doctors to do surgeries.

FLORA LICHTMAN: Oh, to see if your eye has any imperfections on it.

MACARENA GARCIA MARIN: Right, just to measure the surfaces of the eye. So it is actually used in medicine, which is one of those spin-offs, as NASA, calls them, technology that you develop for a purpose, and then it trickles down into society.

FLORA LICHTMAN: Wow, that’s really cool. Well, that’s exactly what Leon was asking about.

MACARENA GARCIA MARIN: Yeah, he has really good questions.

[LAUGHTER]

FLORA LICHTMAN: Before I hung up, I asked Leon why he was interested in space, and his answer caught me off-guard.

SPEAKER: This might be an unusual answer, but I’m a deeply religious person, and science is– for me, has strengthened my relationship with God and I feel 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.

FLORA LICHTMAN: Macarena, I loved this sentiment, and I wondered how it would hit you.

MACARENA GARCIA MARIN: That’s a lovely answer. I think when it comes to the universe– and we look at any of– even the night sky or any of the telescopes’ results– you always wonder about out 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.

FLORA LICHTMAN: Yeah, and there’s awesomeness in both fields. And I mean that in the true sense of the word, that there’s awe.

MACARENA GARCIA MARIN: Yeah, there is absolute awe. And think of the Big Bang, that particular moment, which is the creation of our universe or the– so we can study the universe afterwards, but it can also be addressed from a religious perspective as the moment of creation. So I think there’s a lot to think about that.

FLORA LICHTMAN: Leon had one more thing to tell you, Macarena.

SPEAKER: What you’ve done is super awesome, and thank you for what you’ve done for science and exploring space.

MACARENA GARCIA MARIN: That’s fantastic, and thank you to Leon. But this is, of course, the effort of thousands and thousands of people. It takes a village. And none of this– 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 warms my day to hear that.

FLORA LICHTMAN: Hmm. Thank you, Macarena. Thank you for joining us today.

MACARENA GARCIA MARIN: Thank you.

FLORA LICHTMAN: Dr. Macarena Garcia Marin 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. 877-4-SCIFRI. Catch you tomorrow. I’m Flora Lichtman.

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