The intergenerational jumble of cells

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That's fetchpet dot com slash save I am recording. Do want to just first start by Can you say your name and how you know me? My name is Anne Bird Platt and I am Birrd Pinkertton's mother. It's my mom And I called my mom after I found out this fascinating thing, basically that some cells from my body. hanging out inside of her body and have likely been there for three decades, like ever since she carried me in her womb as I told her Those cells, cells that are genetically me It seems like some of them might have stuck around in your body and become a part of And I am curious what you make of that. You can't have the bag You wantan to use a quote? usese that quote you have them back s, Mama. Oh my right Thank you for telling me how to do my job So my plan here was to explain to my mom very briefly sort of what those cells could be doing inside her and what similar cells are doing to parents all over And that plan went without a hitch Um Can you I mean now, since you're helping me out, can you ask me what are they doing inside my body? What are these cells doing inside my body? I Can I ask it as a statement What do you mean? Can you ask it as a statement? theseselllves are behaving themselves that you know, they're playing nicely with myselfves Well, So here's the fun twist reesearchers don't know. It seems like You know maybe something like a parent child relationship, some of the things that these cells might be doing might be good. Some of them might be somewhat less good. Some of them might be Totally neutral And researchers just No. Dine less good Okay, well let's get into it. Do you want me to tell you a little bit about all like, okay. So I' I wasn't actually, I was just gonna walk you through that intro. I just tell you the whole episode. and' see what happens Okay. Do you have something? No I think Yeah, definitely something is happening. It's Chris. Can you just put your phone on silent? Yes, I can put my phone on silent U on Silent It's unxplainable. I'm Bird Pinkerton. And we originally aired this episode a few years ago when we did a series on pregnancy and parenting We've recently had a bunch of people on the team become parents So I have been thinking about pregnancy a lot And especially about the idea that even though pregnancy is one of the most common experiences on Earth, right? This thing that We all participate in in order to be alive Pregnancy is still Very mysterious mysterious in ways that are Amazing and un insspiring, obviously but also in ways that can hurt parents or att least confuse them And so the story that I tellelling my mom kindind of this perfect example of a lot of the things I learned about pregnancy over the course of my reporting Like it has got A wonder element It also has an element of just the frustrating reality that we are still Very, very far from satisfying answers So Let St start with the basics here This whole like idea of my giving you my cells, right? It's actually a subset of something called timerism, which You know what a chimer is, right Yes, I do. You want to Describe that for me It's like a it's like a replication of the real thing Not exactly. So a chimera is like it's the mythical creature from like Greek myth. So you have like it has like a lion head. big tail and like a go body. Okay. Like a griffin's a chimera, a spphinx, a manticore the composite, right? Okaykay. Right. Let the record show that my mother did know what a chimera was and was unfairly put on the spot. Doesn't sound like your mother knew what a chimera was So that is a chimera in myth But to understand e chimera in biology and what it has to do with pregnancy I reached out to Amy Bodody, who is this biologist at UC Santa Barbara. And Amy says that In biology, the definition of chimera is a little bit broader than in myth. It's multiple individuals existing in one host body And so she was telling me that basically whenever you have a living thing that's made up of pieces of more than one individual That's a chimera. You can find them in plants, you can find them in animals You can even find them in humans. like if you see organ transplantation or something like that, where you have a large tissue, right that's from someone that is a completely different individual, you can consider that person a chimera So this is not like the goat lion hybrid version of a chimera, right? It's just bits of two genetically different people But so technically, mama, Amy was telling me that this process that you and I went through where some of my cells left my body, kind of went into your body That is considered chimerarism on like a tiny scale. So they literally call it micro chimera. because you just have like a few cells. So cells from me, cells from my sister, Chloe, and also potentially from any miscarriages that you might have had So, how many cells do I have from you? According to Amy, It can be infrequently as one in a million cells But we have thirty. tririllion cells in our body So A trillion's like a million million, right? So if you're doing the math could potentially be thirty million cells from me floating around in You Oh. Yeah, but so so some people have more some people have fewer. they're usually more during pregnancy and then your immune system kind of gets rid of a lot of them Around the nineteen nineties is when researchers started to realize that some cells were really sticking around in the parent long term Uh like potentially for the parents whole life which was Surprising, right? And a lot of these cells are probably stem cells. So do you know what a stem cell is After my implosion with Chimera, I am not hazarding, I guess Okay, so so a stem cell is like the the really basic cells that then develop into other tissues. So they're kind of like like jack of all trades flexible cells. They can turn into any kind of cell. So you can basically imagine like The fetus has these flexible cells, right? And then some of those cells travel into the placenta, which Amy was telling me is kind of like the main connector between the fetus and the parent cess Super highway. So the fetus cells sort of travel along this highway into the parent's body, hitching a ride in the circulatory system, probably And they finished their road trip eventually in the heart say or the lungs or the brain sort of all over the body and then they can reshape themselves into a heart cell or a lung cell or a brain cell, whatever they're around and kind of braid themselves into that tissue. doing work in the parents's body, even though genetically they're different from the cells around them. time and but I'm also puzzled. It basically opens up more questions then It even begins to answer. Welcome to the show. So starting around the nineteen nineties, these researchers were sort of like, All right, like what is going on here? Like if these cells are sticking around and becoming part of the body, are they affecting it in some way. Like what are they doing. We don't know. but we have some ideas First of all, Amy told me that it is very possible that At least potentially they are doing Nothing admit it, even though I think there are some functional properties of these cells, but they could just be hanging out Like it is possible that My cells are just like chkis that you love to collect, right? Like your little figurines that don't really do anything. They're just like there It's possible that my cells are just equivalent of that like you have some tiny little cell sized chashkys of me inside of you. I don't like little things anymore. I bought this huge piece of Grammit. the other day in Beron and I logged it all the way home, which was kind of silly. You bought granite? Like you can find granite on the ground. Well, but this was polished. Okay. Anyway, keep going So Again, there is the possibility that these cells are just hanging out like polished granite Researchers have some Good reasons to think that these cells are potentially doing other things There's some studies that show that these cells actually help the host body and so There's ideas out there that, yeah, this this is a good feature to have. So for example There have been studies to look at If someone has a A C section and they look at the tissue in the C section. They found cells from the baby in the parents' scar tissue, essentially suggesting that they are there helping heal the gestational parents body T And again, it's possible that they're just sort of randomly there, right? Because as Amy was saying, like These studies in humans aren't firm evidence because we don't know what they would be doing to heal a body. It's not clear that there are necessarily lots more fetal cells like in this scar site than anywhere else in the body. And that's maybe one of the biggest criticisms of they're just there. There's a few of them. You're just trying to find a purpose to this randomness of cells there If you just sort of step away from humans for a second, there is some more definitive research that has been done in mice So in mice They'll breed female mice with these special males so that Some of their fetuses can create cells that fluoresce It's like a glow in the dark feature. And then the researchers can sort of dissect the mice or use machines to sort of track these glow in the dark mouse fetus cells as they move through. the mouse parent body. If a mouse gets an ear injury, the fetal cells will migrate up to the tissue, seems like they're primed to be able to go in and kind of help recover and heal the maternal body. Which is cool. That's cool And again, like something like that could also be happening in other mammals, including humans So it's not just sort of like C section scars, healing injuries There's also been some research on how these cells at the parent gets from their fetus, could potentially help with heart health There was a mouse model where the heart was injured and they saw these cells these fetal cells migrating to the injury, specializing in helping repair So this is in mice, but it would actually help explain a phenomenon that doctors have seen. in humans, which is basically like a lot of pregnant people develop heart issues. so Your heart is actually doing like a huge workout during pregnancy. This will be no surprise to you, but you know, it's pumping a lot of blood. There's just like more of you and your body is working a lot harder And so researchers have actually compared it to athletes who do long distance sports. So you could just be pregnant and be like, I'm basically an endurance athlete No wonder I hated it the heart is doing this this sort of nine month long workout, it makes sense that a lot of pregnant people develop problems with their heart during this time What's interesting is that Sometimes these problems just kind of fix themselves. like they they go away and researchers aren't Totally sure And some are wondering if the cells from the fetus actually help fix things. L if the cells from the fetus are traveling to the heart and giving it some kind of boost that could explain the sort of heart healing that is happening here. So It's quite fantastic, I think, in thinking about The coolest weirdest biology And again, like This is just one example of the ways that researchers think that these cells could be helping a parent's body sort of heal or fix issues, right Maybe, you know, my cells at some point helped Heal something in you as well I think your cellves need to getet the act together. Let' let's get going here. Okay, I'll work on it. Nothing wrong with your heart, but I'll work on curing your various other ailments and diseases. Sorry. Sorry, I've been such a disappointment to you. It have not been a disappointment. Your cells are just, you know what's happen. This feels like a perfect transition to the next thing here, which is that Sometimes parent fetus cell relationship becomes strained in certain ways Like any communication between parent and child, it's not all sort of heart healing and Star knitting Sometimes the seals from the kid can be what obnxious. This isD playing less well with others. yeah ye So up next how these cells might actually play a role in a whole range of pretty serious diseases We've all been there. You pop into the shop for five minutes and all of a sudden you've forgten where you parked. Car Cour Unfortunately, that lost feeling is what it's like trying to manage your policy with other insurers Here C, come out, come out wherever you are. please. With GIco, you can use the app to easily manage all your policies in one place Did this parking lot have a waterfall? I think you've wandered too far mate. It feels good to find what you're looking for. It feels good to Gaico When you need to build up your team to handle the growing chaos at work, use Indeed spponsored jobs. It gives your job posts the boost it needs to be seen and helps reach people with the right skills, certifications, and more. Spend less time searching and more time actually interviewing candidates who check all your boxes. Listeners of this shel will get a seventy five dollars sponsored job credit at indndeed dot com slash podcast That's indeed dot com slash podcast. Terms and conditions apppply. Need a hiring hero? This is a job for indeed sponsored jobs. Ecema As unpredictable But you can flare less with eGiss, a once monthly treatment for moderate to severe eczema After in an initial four month or longer dosing phase, about four in ten people taking EplLS achieved itch relief and glare are almost cleare skin at sixteen weeks. And most of those people maintain skin that's still more cleare at one year, with monthly dosing.plLSib LBKZ a two hundred fifty milligram per two milliliter injection is a prescription medicine used to treat adults and children twelve years of age and older who weigh at least eighty eight pounds or forty kilograms with moderate severe eczema. 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I gave you a bunch of my cells. happens whenever there's A fetus insie, a pregnant person for a while And in this exchange, Amy Body says that It might be helpful during pregnancy, it might be helpful in the postpartum period. but long term, there could be some trade offs for actually at some point it can lead to health complications And one of the main complications that researchers have been exploring is related to autoimmune disease So like To be really clear from the get go, right? Like this is all very much theoretical, right? It's something researchers are still trying to figure out. So I would not want anyone with sort of an autoimmune disease to immediately assume that it comes from microchrimera or this like exchange of cells, right? Basically, the way that Amy explained it to me is that And we have this immune system and its whole job is to sort of cruise around, check up on various cells, and say like, Is this me Typically your body recognizes self by specific markers on your cell that says, you know like, hey, I am me And it leaves those cells alone. But then if it comes across cells that don't look like itself, then my immune system might say, no Let's get rid of this. But in an autoimmune disorder, the immune system kind of goes haywire, right? Like It starts attacking cells that are part of the body, that are part of itself in some way and that leads to sort of the swelling, the pain, tiredness, like a whole bunch of different issues that are associated with autoimmune disorders And so the way that this is potentially linked to microchimera is It turns out the people who carried fetuses at some point in their lives do seem to be at higher risk for autoimmune diseases The data that we have now focuses on women. But it shows that these diseases are significantly more likely to affect women as compared to men. And some studies have found that the chances of getting some of these diseases actually increases after women's reproductive years. So researchers were kind of looking at microchimera And they were thinking like Okay, people who are getting pregnant Bringing kind of foreign cells into themselves look a lot like them Because usually half our DNA comes from each of our parents These cells come in, they become part of the body, sort of part of the tissue. And then down the line, one scenario is that they do something that the body cells wouldn't usually do, right? something more unique to the kid' seellves. So maybe, for example, they're expressing protein you've never seen before then your immune system might say, hey, that's not self. We need to go ahead and get rid of this. and that can, you know, elicit an autoimmune response. I don't know if we can call it autoimmune because that means self, right? Like is it autoimmune? because It's not attacking the self, it's attacking these foreign cells kindind of the whole problem here, right? Like these cells are both of the parent self and also genetically foreign. So Maybe and again, emphasis on maybe this could be contributing to autoimmune diseases, like maybe these foreign but not so foreign cells are why the body starts attacking itself been a few studies to sort of look at people with autoimmune diseases to look for proof that this might be happening. There's a few different studies looking at individuals with autoimmune disease and they find these fetal cells in the tissue. Once again, like These are mostly sort of correlations like We saw these cells and we saw this problem mayaybe they're related We don't know the root cause. We don't know if these individuals would have gone on to get autoimmune diseases anyways and the cells again just happen to be there So like there's still work to be done here to sort of tease this relationship out and figure out what's going on. but it is sort of One way, at least, that people think that some of these sort of cells from like fetuses could be causing issues Okay, I am fascinated by this I wish there were more information What an interesting possibility I think I think so too Right? So so there's this possibility, this possibility that they're involved in autoimmune diseases. And then the other possibility, which You are not going to like. is that these microchimera might also play a role in canancer. Lay it on. Just lay it on. So So basically cancer is almost one of the best examples of Maybe this is helpful, maybe this is harmful. like Right now it's just kind of deeply confusing Amy was saying, J she got interested in microchimera when she was studying breast cancer. So she was sort of like reading through these papers. And some women had higher amounts of fetal cells in their body and were diagnosed with cancer which would suggest that there could be some kind of a connection again or like a correlation, right? Like more cells from the fetus more cancer potentially. But then there's other papers. this is where it gets really confusing. There's other studies showing that No, actually thoseose cells might be in there trying to help fight the cancer And actually, these cells are protective And so it's a big like, we don't know what they're doing. Are they fighting the tumor? are they making you the immune system more aggressive in making this cancer worse? And we don't know the answer to that So Again, there are a lot of questions here, right? If we can figure this stuff out, like if we can figure out exactly the effects that microchimera have on our body in terms of cancer or also autoimmune diseases, like potentially be huge, right? Amy was saying that Maybe we could figure out if people are High risk for certain issues and help them early, for example. The other exciting thing is some people are again seeing these potential fetal cells. helping with wound healing. and the thought is that it could be a therapy as well providing a boost of of stem cells to actually help fight a disease or help heal. Right now, because this is all such a mystery, like we we're still a very long way away from these kinds of applications, right? which I guess kind of just left me wondering why, right? Like like why do we still have so many questions instead of answers here and no so little. That is a good question Lee Nelson agrees with you That's a good question. Lean Nelson is actually one of the researchers that I mentioned before who first started diving into microchimera in the nineteen nineties And she's been doing A lot of work for many decades on the autoimmune stuff specifically So I asked her essentially like, why we are still so far from answers the most direct Two answers to that are technical So it's the techniques And the other one is funding. Reproductive health in general is very underfunded But this work is also just very hard from a technical perspective. challenge is very simple there all of these little Hirical cells that are very hard to track. And you know, you can put tracers in mice, like we mentioned before, but mice are not humans. Like mouse pregnancy just looks different than human pregnancy, which could lead to different effects. I mean, routinely mice are multiple gestans. They're routinely having like all at the same time, for example I don't know anybody that's had eight or nine kids And meanwhile, you can't like inject human fetuses with Glow in the Dark Tracers cut up human parents in the same way as mice to see what's going on And so as a result, when you're looking at some of these cells in human tissue, you can't really know both where it came from and where it went to and kind of everything about it And then even if you do have sort of some tissue that you're looking at from a human Finding these cells isn't easy, right? It's a couple of cells in a million And so it's kind of like looking for a needle in the haystack if the needle looked like a lot like hay, right? 'cause it's actually got half the hay's DNA And then One extra wrinkle I talked about with both Lee and Amy, but which I've sort of been saving before the end. is that Microchimerism isn't just about Beetuses passing cells to their U It iss actually a lot more complicated. because It goes both ways So not only am I kind of giving you my cells, but when I was in your womb, you gave me some of your cells as well. Of course, which means that You're not just sort of a chimera of me and my sister Chloe and any miscarriages that you might have had You also have my grandmother Muddy's cells swimming around inside of you as well That makes perfect sense How far back to Sa? So it is also possible that Y mom, so my grandmother gave you some of your grandmother's seellves So any researcher sort of looking, Mama at your tissue would be saying Is this cell from Anbert Platt? or is it from her daughter, Chloe or her daughter Bird or her mother or her grandmother or a miscarriage she had And so Amy says it is just hard to parse So we've been talking very simply about this because it is so complex that we our minds can't even wrap around the fact that There's actually multiple generations happening all at once And so studying micro chimera is so hard because you have to find just like a few cells in a million untangle this whole inter generenerational jumble And then figure out like what those cells are doing, what they're up to And that's Part of why this research is going so slowly. You're getting these like two of you know, a thousand piece puzzle, right? And you're like, I think it's a horse, but then you haven't seen, you know, the rest of the body or something like that. And I find it I mean, I find it fat like I guess there's something about it that Like there might be things that we'd never fully understand here, right? Like we are potentially never going to be able to completely untangle the way that like my cells and my sister's cells and cells from your miscarriages have affected your body. Like it's possible. it's always going to remain kind of like a like a parent child relationship, right? Like on a tiny scale. they'll be sort of pushing and pulling and hurting and healing and you know, and it's a relationship we can explore forever and never fully Untangle T be sure, To me, the whole benefit of this kind of research is that what you know now Let's say you really the You one was really able to go into this into a lot more depth They're always surprises. That's the reason everybody does research. They're always like We were looking for X And we found a whole different section of the alphabet Strikes me is a good enough reason to pursue it Um I'm beginning to realize where I came from. It's beginning to make sense that I have maybe some of your cells in my body. Yeah and our brain U ion. am overall more of like a scar healing helper or an autoimmune disease trigger for child. Oh, sweetheart. you are a scar healing helper It's on the record. U and I'm so happy you're here May may have a you year here, mama. We love you. Well love you. And I assume that's it. We're done. Yeah, I think that's it. I think we're done. I're kidding. Thank you for doing this. Very welcome in in a separate space. I will bring you up to date on certain postal events comoming your wayon. and you can bring me up to date on other events in your life This episode was reported and produced by me, Bird Pinkerton. It was edited by Brian Resnik and Katherine Wells, as well as Meredith Hodnot friends the show. We had sound desesign and mixing from Christian Ayala, music from Noam Hasenfeld, Serena Solen checked our facts Ring one It's just really lovely to have nearby I want to say a special thank you this episode to Lee Nelson, who sent so many articles that just really helped orient me and deepen my knowledge here So if you wantna read more about microchimera and autoimmune disorders Look up her body of research. I would also recommend the article that Amy Botody co authored in Biosays in twenty fifteen. you would like to support the show and the journalism the boox does We would love it if you would become a member. It is very easy to do. justust go to vox. com slash members and you won't get access to Alamak's journalism But you will also know that you are supporting Ol of Ox's journalism And for those of you who have emailed to let us know that you signed up because of unexplainable, thank you And thank you to those of you who have left us a nice review on your podcast platform or Told someone in your life about the show.