Nature Podcast

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Nature Podcast fra den 26/2-2015

Presenters: Jeff Marsh and Charlotte Studhart

Duration 20:30

This is the Nature Podcast for 26th of February 2015. I’m Jeff Marsh, and I’m Charlotte Studhart 


                      Now then, if you’ve eaten any processed or packaged food today, a biscuit or a sandwich with shop bought mayonnaise, you’ve probably ingested some emulsifying agents, they’re often added to foods to increase stability and shelf life, but a new study links two commonly used emulsifiers with diseases associated with Gut Inflammation; diseases we’ve seen increase in recent decades. For example, Inflammatory Bowel Conditions like Crohn’s Disease and Colitis and more mild inflammation that seems to promote Obesity. To find out how the study came about and whether I should change my diet, I called Andrew Goerts, who led the study at Georgia State University in the US.

Andrew:          A common threat in these diseases is that they are inflammatory diseases and they’re associated with changes in the composition of Gut Bacteria. Since these are diseases that are increasing in incidence, we thought about what type of factors in the environment, or non-genetic factors might be influencing the Microbiota. Emulsifiers seemed like a very good candidate, particularly because they are in many processed foods, whose consumption have increased in approximate parallel to these inflammatory diseases and because these molecules, emulsifiers, have detergent-like properties.

Charlotte:        Right, and crucially you thought that these emulsifiers might be disrupting the mucus that normally protects the gut wall from these microbes.

Andrew:          Yes, that’s absolutely correct. We hypothesize that they might be affecting the mucus layer directly, or allowing bacteria to penetrate the mucus by changing the surface properties of bacteria.

Charlotte:        So how did you test your theory?

Andrew:          So we administered Emulsifiers to mice, both by putting it in their drinking water and by mixing it into their chow, and then we simply tracked the mice. And what we found was that, in mice that you would consider normal, or wild type mice, the Emulsifiers promoted low grade inflammation that was associated with Obesity and an early stage of Type II Diabetes. In mice that have a genetic predisposition to develop Colitis that’s similar to Inflammatory Bowel Disease, in those mice the emulsifiers triggered Colitis.

Charlotte:        And why is it that low level Inflammation is linked with Metabolic Syndrome with Obesity?

Andrew:          So, there is a Theory called the Inflammatory Explanation for Insulin Resistance; which says that when there is a lot of pro-inflammatory gene expression, that important metabolic receptors such as the Insulin receptor don’t function properly, and that results in over-eating and then that can drive obesity.

Charlotte:        Were you actually able to identify a change in the mucus and a change gut microbes in your mice?

Andrew:          Yes. So, what we observed, was that the mucus was thinner and it resulted in bacteria attaining a much closer localization to the intestinal cells, and not only that, it changed the population of the gut bacteria and specifically, it made them more pro-inflammatory. So we think that is the mechanism by which Emulsifiers are promoting inflammatory diseases.

Charlotte:        And of course, your experiments were done in mice, but do you have good reason to think that the same effects might be seen in humans?

Andrew:          So these are experiments that are in process, at the moment what we’ve observed is that in humans who are obese or have Type II Diabetes, that intestinal bacteria are closer to intestinal cells and the mucus is thinner suggesting that some of the same mechanisms may be at play. The next step will be a trial experiment where people are fed emulsifiers.

Charlotte:        Last year another Nature Paper suggested that artificial sweeteners might be promoting obesity and diabetes. Do you think that food additives are being tested thoroughly enough before they are being put in our food?

Andrew:          I do not think that current testing is adequate. Most testing that is currently done focuses on promotion of cancer, typically looking for ability of an agent to mutagenize DNA, or, are looking at acute toxicity, but I think the paper you refer to, and our results are really implying that this level of testing is not adequate and that a more common consequence of ingestion of chemicals is not going to be an acute illness, but more of a low grade illness that has more subtle effects, but yet very detrimental effects on health.

Charlotte:        Have you yourself stopped eating foods with emulsifiers in them?

Andrew:          I have. My wife generally does the shopping and since we’ve been doing this work over the past year or so, she pays a lot of attention to labels and we have cut down our consumption of foods that have emulsifiers in them.

Research Highlights presented by Noah Baker


Noah:              Sun worshipers might have more to worry about than the DNA damage that occurs while they’re actually sunbathing. New research from Yale suggests that the damage continues for several hours afterwards. The mechanism involves Melanin, the skin pigment that’s thought to protect us against cancer-causing mutations. The research has found that in mice, UVA radiation creates Melanin by-products that continue to damage DNA for up to 3 hours after exposure. If we could find a way to block the formation of these products, they say we could develop an evening after sunscreen that could offer some protection against this delayed damage. Read more in Science.


                       Bacteria hiding in tumours could shield them from attack by the immune system. Scientists at the Hebrew University of Jerusalem studied a bacterium that commonly lives in the mouth, Fusobacterianucleatum. This species has been linked with Premature Birth and Colon Cancer. When the researchers added the bacteria to a petri-dish of tumour cells, they found that it sticks to the cells and activates a particular immune cell receptor. The results could explain why certain tumours, especially intestinal ones, seem to have higher levels of bacteria. The study was published in the journal Immunity.


Alex Whitsy presenting about Ceres and Pluto


Alex                This is Ceres, so that is what we usually think of as an asteroid, it orbits in the asteroid belt between Mars and Jupiter, and then the second one is Pluto, everybody’s favorite ex-planet, which is out there beyond Neptune, which is gonna be visited by a space craft this summer.

Kerry:              Right. So, what are these little dwarf planets like? We should start with Ceres, given that that’s the first one to be visited.

Alex:               Yeah, Ceres is one of those cold, little rocky things. It looks sort of round and lumpy like a lot of asteroids do. Ceres is actually the biggest asteroid of all, it was found in 1801 and this is the first time anyone is gonna visit it; it’s the NASA mission called Dawn. Dawn has been flying around for quite some time in the solar system, went and visited another asteroid called Vesta a few years ago, but it’s gonna go check Ceres this spring.

Kerry:              Right, so that’s asteroid-field -trip-tastic. And, Pluto is lot more well know

obviously, but later in the summer we might hope to learn even more.

Alex:               Yes. New Horizon’s mission will be flying by Pluto in July. The mission has been flying since 2006, it’s so far out in the solar system, and it’s just been going and going in space. It’s actually the fastest space craft ever launched and has been zipping along for the last 9 years, and in July, on July 14th to be precise, New Horizon’s gonna be zipping by Pluto at a relatively close distance to give us our best look yet at what it looks like.

Kerry:              So we’ve known about these two bodies, in the case of Ceres for hundreds of years basically, why is even so interested in them now?

Alex:               Because they are sort of the last unexplored frontier of the solar system. So we know about planets like Mars, we’ve been to Mars about a zillion times. We know about planets like Mercury, and Venus and ones that are a bit closer to us. We’ve sent Voyager and other missions like Galileo and Cassini to the other planets, but we’ve never, ever been to these little, icy outer worlds, I’m talking about Pluto here, and the question is, what do they look like, how icy are they? What is it like to be an object out there, at the fringes, sort of so far from the sun that you don’t get enough sun to be doing much of anything interesting, but you can kind of get ice burning off your surface creating an atmosphere and condensing back down, had does that all work, and what are these other objects out there?

Kerry:              You’ve been profiling a few of the scientists, especially two of the scientists you have working on the Pluto bond mission, tell me a little bit about the feature you’ve written for Nature this week.

Alex:               It’s a brother-sister team, which you don’t often find. Their names are Elliot and Leslie Young. Their father is a famous professor at MIT. He studied the biological effects of weightlessness and trained to be a shuttle astronaut. So Elliot and Leslie, and their younger brother, basically grew up in this kind of space family and they literally grew up playing poker with visiting astronauts when they were little. But the really interesting thing that both their father told me and they told me is, they didn’t just all end up doing space science like their dad, they ended up doing Planetary Science, and they ended up doing Pluto, of all things. Leslie Young was involved in a lot of major discoveries about Pluto, like finding its atmosphere back in 1988, discovering Methane there; discovering relative sizes of Pluto and its big moon, Sharon, and Elliot was involved in the early years in mapping the face of Pluto.

Kerry:              How are they feeling about the New Horizon’s mission, almost achieving its long gone?

Alex:               So, they have been waiting a really long time of course, like everybody involved with this mission. Leslie is actually one of the deputy project scientists and her job is to sort of orchestrate what they called, the Encounter, which is basically the fly by. So she has this unbelievable spreadsheet of everything that is going to happen up to the actual moment on July 19th when we get the closest pass. Her brother is not actually on the mission itself, but he’s gonna be doing some support work.  At the end of June actually, in the southern hemisphere, Pluto’s shadow is gonna cross Earth, and if you are an Astronomer standing right where Pluto’s shadow is gonna cross, you can measure it and get a really good estimate of what the atmosphere is doing and what the size of Pluto is doing. So Elliot is probably gonna be down in Australia chasing Pluto from down there. Another thing they’re gonna do is there’s this telescope in a plane, called Sophia that NASA runs, they’re gonna be taking that down to New Zealand on that day, June 29th when the shadow is passing across, the Sophia team will get in the plane, go up into the air and basically fly in the shadow of Pluto for as long as possible to make observations.

Kerry:              Considering how everyone got excited about Rosetta and Felay, from whom we still haven’t heard from I suppose is still sitting on its little comet, waiting to be found or not. Has that reinvigorated I suppose the world of these missions going these kinda far flung places, and odd little shapes and bits of rock here and there?

Alex:               Yeah, absolutely, cause like you said we’ve done Mars, we’ve done the big ones, so here we are on sort of the edges, but I think the first time you go to any world, no matter what it is, it gets kind of extraordinary. So a comet like one Rosetta went to the comet, you find comets are comets are neat, comets are cool, but when you actually get there and see these jets spraying off the surface, its’ actually kind of fantastic, and the New Horizons team likes to talk about this, there was a series of postage stamps that was issued by the US in, I can’t remember, I think the early 1990’s, and it was all the planets in the solar system and they had nice, big, pretty pictures and all this stuff about them. Pluto is this sad, little grey world and it says “Pluto, not yet explored”.

Kerry:              And now we’re finally getting to do that.

Alex:               We’re gonna change that, we’ll explore it.


Interview now with Lorene Mirello.


Jeff:                 Now your first story is about a huge study launched in the UK to track 80,000 children from birth, what’s this?

Lorene:            So this is called Cohort Study, where Scientists try to track a large group of people over a long period of time and that kind of study allows you to get at questions such as whether smoking during pregnancy impacts how well children do in school, or, how children who are born into poor homes do in life compared to their counterparts from richer families?

Jeff:                 Right ok. And this British study is called the Life Study. This is similar to a study on your side of the Atlantic called the National Children’s Study, which recently came to a halt why did that happen?

Lorene:            So, the National Children’s Study was cancelled in December after about 15 years and US$1.2 billion dollars and that ran into problems in part because of the way healthcare is provided in the United States. It’s a patch work system, we have private insurance, it made it a lot harder to kind of organize participants and get the kind of medical data that you need on an ongoing basis to do these studies, but in the UK, you have the National Health Service and that makes things a bit easier, so I think people are a little more optimistic.

Jeff:                 Now there are other Cohort studies going on around the world, what distinguishes this British study, the Life Study, from those other cohorts?

Lorene:            There are cohort studies going on in Norway and Denmark and they are each looking at 100,000 children, but this British study is different because it really wants to focus intensively on pregnancy and then the first 2 years of life, with the idea that that early start is crucial for future development, it kind of sets the stage for the rest of these people’s lives.

Jeff:                 Correct me if I’m wrong, about 1/3 of these children that are gonna be a part of this study may well live to the age of 100. What sort of exciting information are we gonna glean from such a massive study?

Lorene:            You know, it’s hard to say, the interesting things tend to be surprises and scientists tend to think of questions to ask if they go along, the key with these studies is taking comprehensive data, doing it from the beginning, and taking it consistently. We don’t know what the best are gonna be, but we can be certain that they are gonna be pretty cool.

Jeff:                 Yeah, and I supposed we all have different ways of asking questions maybe?

Lorene:            Right, I mean, we might develop new ways to analyse this data that we don’t know of now, but if you have a good set of data, you can go back in and slice it and dice it to figure things out.

Jeff:                 A lot of stuff, sort of goes on in human throughout its life, how do they choose what sorts of data they are collecting?

Lorene:            They go for some basic pieces of information, they’re gonna storing tissue samples of various sorts that include blood and urine, and faeces, breast milk from the children’s mothers, pieces of placenta and then they are going to be trying to measure data from the environments that these children are growing up in, like pollution, they are gonna be looking at family characteristics, they’re gonna be looking at things like income, they are gonna be filming the children interacting with their parents when they are babies.

Jeff:                 Where are all these samples gonna be stored? That’s quite a lot of “stuff”

Lorene:            They’re going to need some really big freezers; hopefully they’ve built that into their budgeting.

Jeff:                 And our second story then, is about a much smaller Cohort, if you can even call it a Cohort, of top athletes that have had repeated brain injuries and end up with a degenerative disease of the brain. Can you tell me about that?

Lorene:            Sure. This is a condition that has a really long name, Chronic Traumatic Encephalopathy, but it’s a pretty simple idea that if you get repeated head injuries like Concussions, that years later you can start developing symptoms like headaches, and memory problems, and short temper kind of personality changes and there signs of a kind of Dementia. It’s been observed in American football players, there are some cases in Hockey players, and people are looking at other sports like Rugby to see how prevalent this is, but it’s not limited to sports, it’s just that if you’re playing American football, you’re probably hitting your head pretty hard, more than the average person.

Jeff:                 It doesn’t sound like news to me that repetitive brain injuries lead to a kind of mushy brain in older years. What’s sort of new about this?

Lorene:            Well, this condition, CTE for short, was first described in boxers in the 20s and 30s, but since about the mid-2000s, there’s been a lot of research revealing that it seems to be increasing in American football players, possibly as football players grow larger and heavier and hit each other harder, but the interesting thing is that when you look at the brains that people thought to have this disorder, the brain damage that you see seems to mimic in some aspects what you get with Alzheimer’s Disease, or Dementia, that you normally see in much older people. So, one of the questions is whether CTE, this disorder linked to head trauma from Concussion, is distinct from something like Alzheimer’s.

Jeff:                 Right, so there’s a drive in the scientific community to kind of lay out some diagnostic criteria for this condition?

Lorene:            Right, part of what’s driving this is that, this kind of disorder is hard to study; you can only diagnose it after somebody has died by looking at samples of that person’s brain, and so there aren’t tons of samples around. What scientists are hoping to do is see if there is this particular set of signs in the brain of somebody with this disorder that somebody can be used as a common baseline for all the studies that are going on brain samples. Basically to get everybody on the same page and really decide what sets this apart from a similar disorder such as Alzheimer’s disease.

Jeff:                 I’m sort of surprised that there are any samples at all, I mean, how often do footballers donate their brains for science?

Lorene:            Well, this is growing concern for American football players, some 4,500 of them have sued the National Football League here in the United States and that lawsuit is moving towards a settlement that could be as much as US$765 million dollars and as this research has gotten more publicity, there are football players that have essentially bequeathed their brains to science. In our story we talk about a Chicago Bears Defensive Back named Dave Durison, who was basically tormented by Dementia, he killed himself in 2011, but before he died, he asked that his brain be donated to science because he wanted to know whether football made him sick.

Jeff:                 And finally, as we learn more about this disease, do you think that anything is gonna change in the sports industry?

Lorene:            It seems like things may already be changing. There’s a lawsuit pending against the NFL, I think they have already made some changes in response to the type of concern that prompted that lawsuit, and at least in the States, at a lot of different levels, people are looking at whether helmets that are used for professional or college, or even children’s sports leagues are sufficient, and putting in place new rules for how long athletes should sit out after they have been diagnosed with a Concussion, because one aspect of this is that you risk is thought to be higher if you don’t have appropriate recovery time from a concussion.

Jeff:                 Thanks Lorene.


Taking a look at the latest iteration of Neuroscience in the courtroom.


Jeff:                 One way to assess how much pain someone is in is to ask them. But pain is a subjective experience; one person’s dull ache could be agony for someone else. There’s also the possibility that people could lie. A less crude message would be to find the signals of pain in the brain. Lawyers especially would like to use brain scans to get a more objective measure of pain; in fact, such evidence has already been used to settle legal disputes, but some scientists say that these techniques are not yet ready for the courtroom. Nature’s reporter Sarah Reirden has been investigating the issue for a feature and I gave her a call, started off by asking her, how do we traditionally measure pain?

Sarah:              Well, right now, the way that they have people rate pain is to look at a row of smiley faces and some of them are smiling and some of them are like screaming or crying in pain [23:27]. How do you feel, which one matches your pain state? And if you’ve experienced your legs being blown off or something, or you’ve got a headache, you’re going to have a different perception of how bad that headache is as opposed to someone who thinks that this headache is the worst pain they’ve ever had. So, that person’s pain might be a 9, where as a person who’s had a horrible injury in the past, might be like, oh this is just a 3.

Jeff:                 So, obviously it’s desirable to get a more objective measure of pain. When did these brain imaging techniques to assess pain hit the courtroom?

Sarah:              The first time that we know that they did was several years ago in Arizona, there was a case in which a truck driver who had had his arm burnt in a chemical accident had brought in brain scan showing that he was still in chronic pain years after the injury, but they could still being used for quite some time, most injury cases settle out of court, so we really have no way of knowing.

Jeff:                 What are the outcomes of these cases? Are the brain scans helping people to win legal battles?

Sarah:              In this case it did. There haven’t been a whole lot of cases that have gone to trail though; we’re seeing a few right now that are going in the next few months. They are trying to introduce this evidence into court, whether or not the judge will accept it is different question.

Jeff:                 Is this backed up by robustly validated science?

Sarah:              Yes and no. There is a lot of very good science showing that pain is detectable in the brain, especially acute pain, if you burn yourself there’s no question that you could see that fairly easily. Chronic pain, which is the subject of most these suits is little more difficult to detect, there is a growing literature on it. Some of the companies going ahead to offer these have not necessarily validated them in a large number of patients just yet, it’s not clear whether things that hold true for the few patients they look at can actually be generalized to any individual patient that might come in and have his or her brain scanned.

Jeff:                 What makes chronic pain complicated, as compared to acute pain to detect?

Sarah:              Chronic pain is really difficult, scientists don’t understand it terribly well, because it seems to be very tied up in mental state and that’s not necessarily to say that people are imagining that they are in pain, but even after some time the nerves may have healed that were initially injured in your arm or your back or whatever, the brain is still convinced that it’s in pain. And so, well a lot of people are, think that this is something that can eventually be very useful, whether it is or not right now very much depends on the method.

Jeff:                 And in terms of the method, how do some of these studies into that long term chronic pain, how do they actually work?

Sarah:              One company for instance has since developed a database of people that do and do not have chronic pain, not a huge database, it’s about 30 people so far, but they get a range of genders and ages, it’s just to see what the brain looks like between these two groups and then if they have an individual patient come in and which set do they much up more closely with. Another way that people are doing it is take a brain scan, have them lay there peacefully in the scanner, then get up and walk around, or crook their neck in a certain way, whatever it is that makes their pain start, and then lay back down and take a scan of their brain again, and then see what the difference is between those two. And then there’s a third method, takes advantage of the idea that people are experiencing chronic pain have a heightened sensibility to touch, if they just kind of brush their injured wrist or whatever it is, that the brain will light up even though that’s not normally a painful thing.

Jeff:                 Are there people that think that these techniques shouldn’t be used as a reliable measure of how much pain someone’s in?

Sarah:              It’s definitely controversial right now and we’re not sure how reliable they are, it could be that they could be cheated, it could be that they are not picking up on every type of pain that there might be, which is really the bigger concern is that, this is something that is going to be used against patients and plaintiffs, ultimately that insurance company, for instance, might force you to prove that you’re in pain. Companies right now are saying that they can’t prove a negative, that doesn’t mean that someone isn’t going to try.

Jeff:                 Whose decision is it then that whether these tests should be legal to be used in the courtroom?

Sarah:              It’s not so much of a question of legal, it’s a question of whether a judge wants to admit them or not, they’re judges that are convinced that this is solid evidence that needs to be there and that’s going to differ from state to state, from court to court. Standards for introducing something as evidence are different than saying, a scientific conference that we have this statistically valid measure in a courtroom, it’s just like there’s a really good chance that this is true, it’s more likely than not that this is actually supporting their pain, whether or not the case would turn on this particular piece of evidence, or it doesn’t necessarily matter, but it’s one more thing that an attorney could introduce to support the client’s claim.

Jeff:                 Where do you think this is heading, do you think we’re gonna see more neuroscience in the courts?

Sarah:              I think yes, we definitely are going to be seeing more neuroscience in the courtroom. It seems like the number of cases that try and introduce this as evidence has been increasing over the past 2 years, not just in pain, but also in tests for mental illness, for instance, this might be some sort of mitigating factor in somebody’s sentencing. 

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