A very volcanic moon, and better protections for human study subjects

This episode discusses the latest advancements in human study protections and explores the volcanic activity on Jupiter's moon Io.

1. Proposed Protections for Clinical Trial Participants: The episode discusses a new ethical charter to improve conditions and oversight for healthy human subjects in clinical trials.
2. Volcanic Activity on Io: Io's surface is covered with active volcanoes, fueled by tidal heating from its orbital resonance with other Jovian moons.
3. Historical Volcanism: Using isotopic ratios, researchers have traced Io's volcanic activity back possibly to the formation of the solar system.
4. Ethical Considerations in Human Studies: There's an ongoing need to balance compensation in clinical trials to avoid exploitation while ensuring volunteer safety.
5. Implications for Other Moons: The findings on Io also suggest similar geological and potentially biological processes may be occurring on neighboring moons like Europa.

1: Safeguarding Human Subjects

Discussion on enhancing protections for human subjects in clinical trials, focusing on ethical standards and gaps in current practices. Martin Ensrinck: "These people are monitored very closely."

2: Volcanic Io

Exploration of Io's continuous volcanic activity and its implications for planetary science. Catherine de Kleer: "Io has lava lakes that are 100 miles across."

1. Stay Informed on Clinical Trials: If considering participation in clinical trials, research the protections and compensation involved.
2. Support Ethical Research Practices: Advocate for transparent and ethical research practices in both academic and commercial settings.
3. Educate Yourself on Planetary Science: Explore resources and studies related to planetary science to understand dynamic processes like those on Io.
4. Promote Science Literacy: Encourage educational initiatives that enhance understanding of both ethical research practices and planetary sciences.

Jupiter’s moon Io has likely been volcanically active since the start of the Solar System, and a proposal to safeguard healthy human subjects in clinical trials

First on the show this week, a look at proposed protections for healthy human subjects, particularly in phase 1 clinical trials. Deputy News Editor Martin Enserink joins host Sarah Crespi to discuss the risks healthy participants face when involved in early testing of drugs for safety and tolerance. Then, we hear about a project to establish a set of global standards initiated by the Ethics Committee of France’s national biomedical research agency, INSERM.

Next on this episode, a peek at the history of the most volcanically active body in the Solar System, Jupiter’s moon Io. Because the surface of Io is constantly being remodeled by its many volcanoes, it’s difficult to study its past by looking at craters or other landmarks. Katherine de Kleer, assistant professor of planetary science and astronomy at the California Institute of Technology, talks about using isotopic ratios in the moon’s atmosphere to estimate how long it’s been spewing matter into space.

People

Martin Ensrinck, Catherine de Kleer

Companies

Icon School of Medicine at Mount Sinai

Content Warnings:

None

Sarah Krespe
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This is the science podcast for May 10, 2024. I'm Sarah Krespe. First on the show effort to safeguard healthy human subjects in clinical trials. Deputy editor Martin Ensrinck joins me to discuss the dangers these participants face, particularly in early trials that test drug safety. We talk about the new proposal that offers protections for healthy subjects and a registry option. Next, we visit the most volcanically active body in the solar system, Jupiter's moon. IO researcher Catherine de Klear talks about how her team analyzed the moon's atmosphere to discover just how long its volcanoes have been churning, burning, and spewing material into space.

Martin Ensrinck
Before papers are published, a journal should be checking to make sure the work meets certain ethical standards. When animals or human subjects are involved, we have irbs. These are institutional review boards that approve of research proposals before they're implemented, before people start participating. But this doesn't cover all bases of potential harm to human subjects. This week in science, deputy news editor Martin Enserich writes about a proposal for better protections for people that appear to be falling through the cracks of this safety system. Healthy human subjects involved in clinical trials hi Martin. Welcome back to the science Podcast.

Martin Enserich
Hey, Sarah.

Sarah Krespe
Hi.

Martin Ensrinck
So this is kind of emphasizing healthy human subjects and how they're treated in research. Is it a big difference between someone who has an illness that wants to enroll in the trial and someone who is healthy?

Martin Enserich
Yeah, there is a big difference. I mean, when we talk about clinical trials, we talk a lot about what is called phase two and phase three clinical trials, where you typically enroll patients and they hope to have a treatment that might work for them. But a lot of the research on healthy volunteers is so called phase one trials. That's typically small studies with a small group of people to test, for instance, whether a drug is safe before you even start giving it to patients. Often very cumbersome trials. You go to a clinic or a hospital, you spend a week there or several weeks, take your blood every day. They take urine samples. Those people are really monitored very closely. And the other big difference is that those people do it for the money. It's not altruism that they don't expect to get better because it's an unknown drug, but they're in it for the money. So that can lead to exploitation of people who need money.

Martin Ensrinck
What protections are in place now? Like I mentioned, you know, there are like, irbs that are supposed to review protocols that involve human subjects. Journals are supposed to look and make sure that certain ethical standards are being met. Are those not doing enough for these phase one trial participants, these healthy subjects?

Martin Enserich
Well, they do cover those people, but the initiative to better protect them, which has been sort of a multi year project, it says that basically there's not enough specific attention for them, that it's sort of a world that's hidden from public view, that we don't hear a lot about them, but that they have special vulnerabilities because they're often poor people, often from marginalized communities, sometimes homeless people, former prison inmates. And even though the proposals path, ethical panels, and people sign a consent form and everything, but they can still be.

Martin Ensrinck
Subject to exploitation, who is looking into new guidelines, new protections? What's this group and how did they form?

Martin Enserich
It's an initiative that was started by an ethics committee at INSER, which is a french national research institute. They've been looking into this for a couple of years, and they got together an international group, a committee. They held a couple of meetings. They also started involving companies that do these studies, but also healthy volunteers themselves. And so this sort of snowballed into a project. They've produced a draft of what they call an ethical charter that enumerates everything you should think about when you do these studies. I was at a meeting in Paris two weeks ago where they discussed that charter and also started talking about, well, how do we disseminate this? How do we give it light, so to speak?

Martin Ensrinck
What are some of the protections proposed in this charter?

Martin Enserich
Well, they have a whole list of things. It starts with simple things like the facilities where you house these people during a trial. They need to be comfortable that doesn't need to be Wi Fi. There has to be enough space. You need to monitor people very closely for harm, not just during a trial, but also in the long run.

Martin Ensrinck
Like follow up?

Martin Enserich
Yeah, follow up after the trial. And another thing is make sure that people don't enroll in the trial while also being in another trial or shortly after another, because that could harm the people, but also could bias the results from your finding. There were a couple of scientists at the meeting who have studied these healthy volunteers, and one of them told me that he met people who had been in 80 trials in the course of his lifetime. So, yeah, that's incredible. These are really professional. They call themselves professional guinea pigs. That's what they do for a living. And so there's a call to say, we need to have a register where you can see whether people have already been in other trials and if they've observed a period after every trial to make sure that the drugs have left their body before they join the next one. Things like that.

Martin Ensrinck
Is there anything about payment? You know, sometimes there's concern that if you offer too much money, then a person might go against their own health and interest in order to participate in a trial. Is there a limit on how much they can pay?

Martin Enserich
There's not a limit, but that is very much an active discussion. You're right. If you promise people too much money, they may become too eager almost to join. If you give them too little, it really is exploitation. So there's some discussion about that. It probably depends on the local context, what the right amount is. They do warn against so called completion bonuses, which means if you stay in the trial all the way to the end, you get a bonus. That's understandable from the company's point of view, because you want the data set to be complete. You don't want people to drop out after a couple days or midway during the study. But on the other hand, if you have a very high completion bonus, that would incentivize people not to drop out, even if they feel terrible, or even to conceal side effects, which is also something you don't want. So the charter says these bonuses have to be modest, whatever that means, right?

Martin Ensrinck
Yeah. One number stood out to me in the draft that I read, which was $9,000 for being involved in a trial. That seems like pretty hefty amount of.

Martin Enserich
Money, but looks like a lot of money. But the health volunteer I talked to, who was also at that meeting, the trial lasted more than a month. It included the Christmas holidays. Do you really want to be in a clinical study over the holidays. And she also told me about the other things that happened to her. In these trials, you can have adverse events where one time she had started sweating profusely and her heart started pounding because of a drug effect. The way she told it was definitely not an easy life. Even though it may look like easy money, it really isn't.

Sarah Krespe
Martin, do we know something about the scale of these trials, like how many are happening in a year or how many people are involved in something like this?

Martin Enserich
We don't know a whole lot about the numbers. One of the organizers of this meeting had done sort of a rough search of clinical trial databases a couple of years back. He found that there are about 13,000 trials ongoing at that point that included healthy volunteers. That was not all just phase one, but also phase two and three. But that's actually probably still an undercount, because phase one trials, you don't have to report them in these databases, so you can organize one without making it public. So the real number may even be higher. It's difficult to get a handle on the. These trials often are not. The data are often not published that come out of them. They remain sort of company secrets, almost. And there's not a lot of study going on of this whole phenomenon. So we just don't know this world really well.

Martin Ensrinck
Who's conducting these studies? Are we talking about academic institutions, commercial industry, phase one trials? Are they often conducted at a university?

Martin Enserich
Well, most phase one studies are sponsored, paid for by the pharmaceutical industry. The industry does some trials itself, and some of them happen in, for instance, academic medical centers, but most are farmed out to what they call contract research organizations, basically companies that specialize in setting up these trials and that they get some money from the pharmaceutical company, and what they produce is a study report. That's it?

Sarah Krespe
Yeah.

Martin Ensrinck
So it's very professionalized. There's this intermediary that's gotten what they want to study from the pharmaceutical company. Then they set up their own version of the trial and recruit people and pay them.

Martin Enserich
And that's a billion dollar business. It's a huge business. And there have been a couple of disasters with phase one trials. In 2006, a group of volunteers got very, very sick in London during a phase one study. In 2016, there was an accident in France where one man died and five others got very sick as well. So there is an inherent risk, and that makes sense, because the whole point of phase one studies is to see whether something is safe. So inevitably, sometimes you're going to find something that isn't.

Martin Ensrinck
And there's this huge translation gap from animal research and vitro research into humans.

And the big first hurdle is making sure that it's safe in people.

Martin Enserich
That's right. That's right. And no matter what you do, you can never say, based entirely on animal studies, that a drug is going to be safe. That's why they do phase one studies. In the wake of those accidents, the rules have tightened. For instance, after the London trial of 2006, the European Medicines Agency said, you can't give a whole group of people the same drug at the same time. You have to start with the first person, observe what happens, and then the second and the third and so on. So there are already safeguards there in place as well.

Martin Ensrinck
Once they kind of finalize what they've come out, what comes out of this committee, what happens next?

How does it get applied, or how do people take it up? How does it get enforced? I guess that's the word we want to use.

Martin Enserich
After this meeting two weeks ago in Paris, they are going to sort of finalize this ethical charter. But, yeah, the plan is to distribute it widely to make sure everybody sees it, and they hope that regulators in countries will read them and realize that this is a group that needs some additional protection. They also hope that the companies that run the trials will take notice. There are other documents about clinical trials, like the declaration of Helsinki, which mentions participants in general, but not specifically healthy, paid volunteers. And so they're also hoping that documents like the Declaration of Helsinki will incorporate some of the elements that are in this charter.

Martin Ensrinck
Yeah, that declaration of Helsinki is something people have been paying attention to for a really long time. It's kind of the overarching guidance for everybody.

Martin Enserich
It is.

Martin Ensrinck
So if it were incorporated into that, it really would have a strong effect.

Sarah Krespe
I think it is.

Martin Enserich
It's sort of the cornerstone of trial ethics. But at the same time, it's like an umbrella document. It doesn't give you a lot of specifics. It's also not about, for instance, research on pregnant women. So the declaration of Helsinki is not meant to be very prescriptive in details. So we'll see how much of it would end up there.

Martin Ensrinck
All right, thank you so much, Martin.

Martin Enserich
Thanks for having me.

Martin Ensrinck
Martin Ensrinck is a deputy news editor. You can find a link to the story we discussed@science.org.

Sarah Krespe
Podcast stay tuned for a chat with researcher Catherine de Kleer about the origins and history of volcanic activity on Jupiter's moon IO.

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IO, which is the innermost of the larger moons circling Jupiter, is the most volcanically active body in the solar system. While we know it has a lot of eruptions, we don't know when all this activity started. This week in science, Katherine de Klear and colleagues wrote about using isotopic ratios in the moon's atmosphere to estimate how long it's been spewing matter into space. Hi, Catherine. Welcome to the science podcast.

Catherine de Kleer
Hi, Sarah. Thanks for having me.

Sarah Krespe
Oh, sure. This is such an interesting study. First off, what would it be like to be on the surface of this moon on IO, it is.

Catherine de Kleer
Although it's just the size of a moon, it's got something like 400 active volcanoes on its surface, and plenty of them are essentially always active. It's not just that there's one eruption and then nothing for ten years, and then another eruption constantly putting out magma. IO has lava lakes that are 100 miles across. That's the size of some of the great lakes in the United States. So it's lava as far as the eye can see. Wow.

Sarah Krespe
So it sounds very dangerous. Like if we wanted to visit, it might be a tough thing to bring a craft there.

Catherine de Kleer
Depends where you are on the surface, for sure.

Sarah Krespe
So the heated interior of IO, the source of all of this volcanic activity, is actually due to the way it's pushed and pulled on by the other large moons around Jupiter. Can you talk a little bit about how it's internally heated all the time?

Catherine de Kleer
The process that heats IO's interior is called tidal heating, and this occurs because IO is in what we call an orbital resonance with two of the other large moons of Jupiter, Europa and Ganymede in particular. Every time that Ganymede goes around Jupiter, Europa goes around exactly twice, and IO goes around exactly four times.

The reason it's important that this is exact is that they're encountering one another at the same points every orbit, and this is pulling them into elliptical orbits when they otherwise might be in circular orbits.

So when IO's in this elliptical orbit, its distance from Jupiter is changing over time. So the amount of tides that it's experiencing is changing every 1.8 days. So it's being compressed and extended and compressed and extended every 1.8 days. And this is causing friction in its mantle that is enough to actually melt the rock and produce magma.

Sarah Krespe
Lot of activity going on in this poor little moon. So the idea here was you're trying to learn about the history, but due to all this erupting, the surface is not very informative. You don't see the craters that you see on our moon coating it and kind of indicating age over time of different big pock marks. Instead, you look to the gases in the atmosphere. Can we call it the atmosphere of IO?

Catherine de Kleer
We can call it an atmosphere. It's nano bars in pressure. So it's definitely a very tenuous atmosphere. That's part of what made this study challenging. But, yeah, yeah, I think it qualifies as an atmosphere.

Sarah Krespe
Right. So there are gases clinging tenuously to this moon, and you are able to look at them and determine something about the composition there. How are you able to see gases on this moon?

Catherine de Kleer
So we use a large radio array. So, array of radio telescopes that are functioning like an interferometer. It's in the Atacama desert in Chile, and it's called Alma, which stands for the Atacama large millimeter and sub millimeter array. So we're specifically looking at emission lines that are produced by changes in the rotation state of molecules of sulfur dioxide in IO's atmosphere.

Sarah Krespe
Why was ALmA well suited for looking at this question on IO?

Catherine de Kleer
A couple of the things that are really unique about ALmA and really enabled this study is, first, it's operating at some millimeter and millimeter wavelengths. And at these wavelengths, you can really well detect molecules. Not atoms, not ions, but specifically molecules. So if you're looking for molecular gases in an atmosphere, these are the right wavelengths to be looking at. AlmA is also a huge array. The main array uses roughly 40, 43 dishes.

And what that gives us is increased sensitivity. So ALmA has an unprecedented ability to detect very faint lines because it has so many dishes and therefore just so much area with which to collect photons from astronomical objects.

Sarah Krespe
Why was sulfur dioxide. An important component to look into.

Catherine de Kleer
Sulfur dioxide is the molecule that we look at because it makes up 90% of IO's atmosphere, and it makes up almost everything that's coming out of the volcano. So IO doesn't have any water, it doesn't have any carbon dioxide. As far as we can tell, the volcanoes are producing sulfur. Frost on its surface is made of sulfur. The gases of its atmosphere are made of sulfur. Sulfur is just the primary gas and ice forming element on IO.

Sarah Krespe
Okay, so we're going to add smelly to the list of inhospitable characteristics.

Catherine de Kleer
Yes.

Sarah Krespe
Where were you able to tell, using the telescope about the sulfur dioxide in the atmosphere?

Catherine de Kleer
So, with this alma observatory, we measured the ratio of sulfur 34 to sulfur 32. Sulfur 32 is the most common type of sulfur. It has 16 protons and 16 neutrons. Sulfur 34 is a heavier version, a heavier isotope of sulfur that just has two extra neutrons.

Sarah Krespe
Were you expecting one of these to be depleted because of the volcanic activity?

Catherine de Kleer
We had hypothesized that the ratio of the heavy to light sulfur would give us, like a fingerprint of the longer term evolution of IO and its volcanic outgassing. So IO probably started with a standard ratio of sulfur 34 to 32, the sort of solar system average ratio which we get from meteorites over time.

If it had been volcanically active for 4 billion years, let's say roughly the age of the solar system, then the material that has been erupting onto its surface from its mantle is coating its surface at a certain rate. And given that rate, it would eventually need to be recycled back into the interior. If you just calculate out the volume of material that's coming out onto IO's surface over time and just multiply that over the history of the solar system, you find that if IO has been volcanically active for the whole history of the solar system, then all of its material has been processed through the mantle, erupted and recycled back into the mantle something like tens to hundreds of times.

Sarah Krespe
Wow. So it recoats its own surface, and then that surface becomes the mantle as it sunk under new layers. And then you can say, okay, well, the whole thing has gone through because the sulfur ratio has changed. You could say, oh, this has been up through the atmosphere.

Catherine de Kleer
Right? So as part of this process, every time you erupt the magma onto the surface, you're outgassing some of this sulfur dioxide. The sulfur dioxide that comes out of the volcanoes, forms IO's bulk atmosphere. And over time, that atmosphere kind of settles gravitationally. So if you're close to the surface, your ratio of the heavy sulfur to the light sulfur is very slightly higher than in the average atmosphere. Whereas if you're at the top of the atmosphere, the ratio of the heavy to light sulfur is very slightly lower than in the average atmosphere, meaning that your sulfur, on average, is a little bit lighter. The reason this is important is because Jupiter's magnetosphere, and in particular charged particles within Jupiter's magnetosphere are impacting this upper atmosphere and causing material to be lost.

Sarah Krespe
Okay.

Catherine de Kleer
The material is actually being lost from IO's atmosphere at a rate of roughly one ton per second.

Sarah Krespe
So Jupiter is whipping away this material from the upper atmosphere and it's slightly tilted towards the lighter isotope or the lighter version of sulfur dioxide that's going to be whisked away by Jupiter.

Catherine de Kleer
Exactly. And it's a tiny effect on any given day. It's not making much of a difference to the overall atmosphere. But if you then recycle what's left behind, which, again, is very slightly heavier because of that stuff that was lost, you recycle that back into the interior, you erupt it again in the volcanoes, and you do this over and over again for the history of the solar system, the overall inventory of sulfur on IO becomes heavier.

Sarah Krespe
Yeah. So if you do the math, you can then figure out from the current ratio of heavy to light sulfur dioxide how long this activity has been going on, how long the eruptions have been happening.

Catherine de Kleer
That's right. And the direct thing that you can calculate from the sulfur ratio, the sulfur 34 to 32 ratio, is the fraction of sulfur that has been lost over time.

It's still like 6%. It's just that it probably started at 4% heavy sulfur and now it's 6% heavy sulfur. So the change is relatively minor, except that that's huge in geochemistry's terms.

Sarah Krespe
You know, we've kind of been saying, well, if this has been happening since the beginning of the solar system, is that what your math is saying, that this has been happening 4 billion years or even more?

Catherine de Kleer
Yeah. So you take this kind of sulfur loss and you say at IO's current mass loss rate, or like within a factor of a few of IO's current mass loss rate, how long would it take to lose that much sulfur? And mathematically, it would take from half the age of the solar system to five times the age of the solar system to lose that much at IO's current mass loss rate. Obviously, IO has not existed for more than one times the age of the solar system.

Sarah Krespe
Yeah, true.

Catherine de Kleer
Okay, so we can kind of put these bounds that assuming IO's current mass loss rate, it's been losing mass at half to the full age of the solar system, with kind of a preference towards the full age of the solar system.

Sarah Krespe
Did that surprise you? Did you think that IO has always basically, since its formation, been in resonance with its other moons, that it's been tidally heated by Jupiter? Did you think all of this would have been happening for the entirety of its existence?

Catherine de Kleer
This was the hypothesis we were trying to test. So actually, people who run computer simulations to simulate how the solar system formed and how the moons form have noticed in their simulations over the past 20 years that when you start to form in a computer, the Jupiter system, you do frequently capture its large moons into resonances very early on, like tens of thousands to hundreds of thousands of years after the start of the solar system, which is nothing in geological or astronomical time.

Sarah Krespe
This was one of the things you thought might be the case.

Catherine de Kleer
Exactly. In a sense, this is a confirmation of those predictions.

Sarah Krespe
What does it mean for the other moons that have been in resonance with IO this whole time? The entire history of the solar system.

Catherine de Kleer
IO's long term history, is really closely linked to that of Europa and Ganymede. So if IO has been in this orbital resonance and being tidally heated for the history of the solar system, the natural extension of that is Europa as well, has been in this orbital resonance and tidally heated, which means that what?

Sarah Krespe
That it's been icy and watery its entire history as well. And it's not something that came on with resonance or came on later.

Catherine de Kleer
So Europa has this water ocean. That water ocean would probably exist without tidal heating. It's not necessary to melt the water, but the tidal heating is an additional input of heat into Europa. And Europa is considered one of the most potentially habitable environments in our solar system, specifically at subsurface ocean. And heat, or an energy source in general, is required for life. So any amount of heat that you're putting into this system increases its potential habitability. So the fact that you've had this tidal heating input into Europa as well, over the history of the solar system, I guess, increases its potential long term habitability.

Sarah Krespe
What else would you like to know about this system? Is there something that we can only answer by visiting IO?

Catherine de Kleer
Certainly.

I would love to have a spacecraft visit IO at some point. There are a couple of related things that I would love to do. There are two other stable isotopes of sulfur, sulfur 33 and sulfur 36. And actually, they're less abundant. And so we weren't able to measure those ones. But if we could go visit IO with a spacecraft and actually detect those isotopes in situ, that would be a test of the model that we've used to interpret our observations.

Sarah Krespe
And is there more you could do with the array or telescopes here on Earth or maybe a space telescope?

Catherine de Kleer
One of the big questions that I would love to know the answer to that, I think may be possible, although it might require visiting with a spacecraft, is whether iodid used to have water and carbon dioxide. You know, the other three big moons of Jupiter, Europa, Ganymede, and Callisto, they all have ice shells. They all have water oceans under those ice shells. I think the standard thinking is that IO formed pretty dry without much water because it was closer to Jupiter and it was just too hot for water to condense there. But did it collect some water? Did it once have a small water ocean? And did it lose that over time?

Sarah Krespe
Yeah. How would you be able to tell that, considering that it's resurfaced a bunch of times?

Catherine de Kleer
Yeah.

The best way to detect a past water ocean and the way that it's been done on Mars and Venus is to look at the ratio of heavy to light water. So that's deuterium to hydrogen in water.

The problem is that first you need to have hydrogen or water anywhere, and if it's there, it's below the abundance that we've been able to detect so far.

Sarah Krespe
Thank you so much, Catherine.

Catherine de Kleer
Thanks for having me on.

Sarah Krespe
Sarah Catherine de Kleer is an assistant professor of planetary science and astronomy at Caltech. You can find a link to the paper we discussed@science.org podcast and that concludes this edition of the Science podcast. If you have any comments or suggestions, write to us at sciencepodcast aaas.org dot to find us on podcasting apps. Search for Science magazine or you can listen on our website, science.org podcast. This show was edited by me, Sarah Crespi, and and Kevin McLean. We also had production help from Megan Tuck at Prodigy. Jeffrey Cook composed the music on behalf of Science and its publisher, AAA's. Thanks for joining us.

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