Special Episode: Mary Roach & Replaceable You

of the year. If you'd like to sneak a peek at the books that we'll be reading later this season, as well as check out the ones we've already covered, head over to our website This Podcast will Kill You dot com. There under the extras tab you'll find a link to our bookshop dot Org affiliate page, which has a bunch of podcast related lists, including one for this book club series. I am always updating this list, so check back in regularly to see what's coming up later this season.

on YouTube. Make sure you're subscribed to exactly Right Media's YouTube channel so you never miss a new episode drop. Our human bodies are astoundingly complex, intricate machines that allow us to interact with, exist within, and move about this world.

Even at this moment, whether you're driving home from work, out for a walk, cross stitching on the couch, or just sitting meditatively, your body is performing a whole host of functions, some of which you might be aware of, like listening to what I'm saying, pumping the brakes, or picking up your dog's poop, and others that you don't even realize are happening, like digesting lunch, maintaining balance, or

growing hair one micrometer at a time. When you think about all the things that have to go right every second of every day to keep us healthy and alive and doing what we want to be doing, it's hard not to be amazed at what our bodies are capable of. In general, they do such a good job of keeping as functional that When something happens that throws a figurative wrench in our figurative machine slash body, we are often

left with only imperfect solutions. The human body is a difficult thing to replace, but that hasn't kept people from attempting to do so for centuries. From the earliest skin grafts to three D bioprinting, scientists have made incredible strides in developing suitable replacements for our various body parts, and Mary Roach is here to tell you all about it.

The ever delightful Mary Roach joins me to discuss her latest book, Replaceable You, Adventures in Human Anatomy, which takes reader's body part by body part through the science of regenerative medicine. You'll learn what's so special about a pig's heart, why hair transplants work as well as they do, how to choose an OSTOMEI bag, what it feels like in side, in iron lung, and so much more. This journey is alternatively funny, bizarre, revelatory, passionate, and inspirational. In other words,

it's a classic Mary Roach. By the end of the book, you're left in awe of the scientists who have accomplished so much to heal those in need, the brave patients who have dared to put their lives in their hands, and our bodies themselves, whose stubborn instinct to protect us is often the thing holding us back from creating a perfect replacement. I am beyond thrilled to get to chat with Mary again, so let's take a quick break and get started. Mary, it is so great to see you again.

Thanks for joining me today.

to do with fat or stem cells. She mentioned this surgeon who had created he'd created a replacement penis for a man using his own metal finger, and I of course pictured the finger moved as is from the man's hand and just like stitched in place, able to move and like you.

It just it tends my books tend to happen. There's one chapter and then there's another one, and then I think, well, what could be the kind of topic the umbrella that goes over all of this. So it's never me going yeah, I'd like to do a wide ranging book on regenerative medicine and prosthetics, which is not what the book really is, but that's how it goes with me.

settled in its new home. So there'd be it was called a pedical flap, and it was it was, you know, there'd be the piece that's going to be transferred and then sort of a peninsula connecting it to its original owner. And what that meant this going back to the eighteen hundred's Charles Setio I believe his name was, I had this. I remember reading about how he had used He described it.

Of course, it's in French an chien denois, and I'm thinking, well, I don't know much about Danish dog breeds and I'm picturing something small, but no, you meant the great Dane. So this person had to lie with a great Dane for a number of weeks while the you know, the keeping the blood supply from the dog, but in fact he terminated the project early because of the continual and excessive movements of the dog. And I'm like, what did you expect.

of a circus. And at certain point surgeons realize it's going to work pretty well even if you just you don't keep it connected to it to the host. You can take a patch and put it. It's kind of a bio dressing. It isn't as though the person becomes part dog or port frog or par chicken, especially with

a burn a big burn. The immune system is suppressed initially, and that allows foreign graft to sit there and to kind of take for a while, and eventually it'll slough off, or the surgeons will remove it and put on a graft from the from the patient themselves, which works. But as a kind of a band aid of bio dressing. They're called zoografts or zenographs. They do work. You know, it protects it, it keeps it from drawing out. It

sounds really weird, but it did work fairly well. Chickens frogs were used often.

of the things. But you know, how did we go from chickens frogs to today where we're actually able to use you know, autograph someone's for someone's own tissue and will in the future people look back and go, I can't believe you used the own tissue like we now just print sheets of skin from someone's body.

another part of the body. You know. Frequently yeah, you know, you'll take a graph from the thigh or the back, you know, and and when it's somebody has a really serious burn that's covering you know, sixty percent of the body or something, you you don't have a lot of options, not a lot of real estate to be taking those grafts from so and you can wait for them to heal and then reuse that space. I mean, it's quite

an undertaking. So some of these new newer developments like the spray on skin where you kind of you know, you take a graft and it's meshed and you kind of fill in the spaces and the mesh with some of the person's own cells sprayed on there.

Goat's milk, cow's milk. I mean, it was just a lot of very excited journal articles going, this is going to be this is going to be huge milk transfusions. So we're going to apply to the hospital to get funding for a cow that you know, that will keep on the grounds. And very quickly medicine came to its senses and realizes it's just basically It's similar to giving someone saline to keep their blood volume up in the

case of a hemorrhage. If somebody's lost a lot of blood, it prevents going at a shock, and so it's useful in that way. There wasn't something inherent in milk, you know, that made it this miraculous substance. But it wasn't an entertaining period, and it was like eighteen seventy eight, there was this flurry of milk transfusions.

of them bought them about two months. This is a pig organ it's a genetic edit so that some of the surface proteins that tell the human immune system like this is really foreign, get it out of here. So there's these genetic edits to make this heart more like a human heart, to try to fool the immune system and to prevent hyperacute rejection, which is if you put in a pig heart, like right away, the body's going to attack it, it's going to start turning black. Is

knock a work. So they've managed to get around the hyper acute rejection, but there are still rejection, you know, longer term rejection issues. So it's not thought of at this point. It's not a permanent like a human transplant human heart or kidney transplantation. You're buying time in the hope that you'll make your way up the list and be able to get a human kidney or heart whatever it is. So it's a stalling mechanism. It's a way just to buy time for the person you know, who's

otherwise you know, could die. Unfortunately, that means the patients that are getting these hearts are are not in tip top shape and that may be contributing to to the short survival time. Tim Andrews was in better shape than some of the previous recipients. No one is quite sure, you know, why is it only lasting two months? What do we need to do next? How many more edits are we going to do? Or is it something else

entirely that's going on. There's also concerns about zoom no ses diseases that could go back and forth between the animal and the person. I mean, it's amazing to think that we can even get two months using something that

is that foreign. You know, it's a pig heart, so you know in pig valves have been used before, but that's that's not live cells, you know, that's a sort of extra cellular material, so not quite the same I visited a place in China where they're raising these pigs and so they're super cle It's a super clean pig sty, which to me was this lovely oxymoron. I'm like, what do you mean it's a clean pig sty, But it is. It's they're tested for forty bacteria, viruses, fungi. The whole

place gets disinfected every few days. The staff are not allowed to leave. They work for three months in the facility, and then they're swapped out with someone else. So very very strict cleanliness and hygiene and sterile protocols for these pigs. You know what I saw. I wasn't allowed to go in. Of course. I I go all the way to China, thinking well, I'm going to get in to see the pigs. And they're like, of course you're not going in. You're full of germs, you know. And then they're like, you

can see it from across the river. There there's the facility, you know. And then we went over to a kind of a control center where I could see them, the pigs, that is, on a video screen in real time. There they were the very clean pigs, still pooping on the floor. I mean, they're pigs.

bias that there is for wholeness. And it's a really difficult decision to make for amputation, especially when it's not medically necessary, or when it's a parent that has to make this decision or.

or surgeon would say you should remove this foot. But she had spina bifida and that she had like a tumor on her spine that it caused this foot to be twisted to not work well. She had had a half dozen operations, never getting to the point where she was improving, always getting worse. And she's described watching people out hiking and watching people who had prosthetic limbs in artificial foot who were able to walk or run or

hike and do things that she couldn't do. And they've got a prosthesis and she has a natural foot, and she just decided, I don't want this foot. I want this gone. And it was very hard for her to find a surgeon willing to do that, because you're talking about removing healthy in quote, I mean it's healthy, it is just not functional. For her, it was very hard to find a surgeon willing to do that. She finally did, she was so much happier. She can do all of

those things she would see other people doing. So there is a bias for wholeness, that's part of it. But it's also a surgeon. You know, no one's going to call a surgeon to task for Let's try another operation, Let's see if we can make this foot work, you know, because cutting a foot off feels extreme final, there's no going back. Also, the surgeon may or may not have experience and amputations and may be concerned about you know, what if there's phantom pain, what if I don't do

it right? You know. You need also to convince the insurance people. That's another issue. So so it's it's a tricky thing to take off your foot and as you mentioned when when you ask the question, when it's a parent trying to make that decision for a child, that's really hard to do.

on there. But compared to a hand, it's a much more successful thing to replace.

talk about your experience in the iron lung. Thanks to vaccines, we don't see the iron lung wards these days, but it was a whole community, like a whole culture, and so it must have been really incredible to kind of see this device and then experience it yourself.

do you know anybody who is still using one? And there were a couple of people, and she put me in touch with this man whose wife had recently died, and I wrote to him and said, you know, I'm really curious about this. Could I come and spend the night in your wife's iron lung? Which is like a cold email, like hello, you don't know me. As it turned out, he did know me from having read one of my books. So that was helpful because I think

otherwise you feel like you're really weird. Go away, yes man, Yes, yeah creepy. So yeah, it does sound kind of creepy, like I want to spend the night in you iron love. So anyways, his name was Mark, and Mark said yes. So I went out and I didn't know what to expect.

I imagined it being a little simpler than it was, Like I wanted to eat a meal in there, and that was frowned upon because that can be very dangerous because if you have a machine, and I should back up and just say, an iron lung is different from a ventilator in a hospital that is a positive pressure ventilator, you know, the thing that we're all used to seeing where you're it's kind of inflating your lungs like a party balloon, which is very different negative pressure ventilation. That's

how we breathe. So you have muscles to pull apart your rib cage and pull down your diaphragm, and that lowers the pressure inside the lungs. It pulls air in and then when the muscles let go, it squeezes it out. So it's a very gentle and natural thing that is mimicked by these machines. They create a vacuum in this sealed tube that you are inside, and that opens up the chest, pulls in air and then it goes back out.

That means you're inside there, but your head is outside, so it isn't quite as claustrophobic as you would think. It is a very strange experience to have a machine decide when you will inhale and when you will exhale. And so if you're trying to eat, say you had shoot some food and you were about to swallow it, and the machine decided that's when you're going to inhale, that could be a serious choking hazard, or you could get you could get food inside your lungs, which could

cause pneumonia, you get bacteria in there. So they're like, no, you won't be you won't be eating dinner in the iron lung. Now that would take some coordination and practice, so we're not going to do that anyway. So I'd had this idea that I would spend the night in the iron lung, and Mark had brought in a couple assistants. It's kind of a you know, it's kind of an undertaking. Kind of looks like a hot water heater lying on its side, okay, but with a sort of like an MRI.

You know, where this bed rolls out. So you get on the bed and then they roll you in, but then you've got to get your head out this opening yeah, so you get your head out the opening and then the next needs to be really tight to keep because it has to be a sealed right to create the vacuum. It's a little hard to explain without seeing it, but it's got to be. It's got to be a seal.

So that's like not a comfortable way to sleep, you know, and to have that tight and I'm like, I think this is too tight, and they're going, no, it's not quite tight enough. Great, you know, and mark It said, oh, it's really relaxing. You'll be asleep in no time. So I lasted about nine minutes in the iron lung. So because the collar is so tight, you have this weird simultaneous sense of like breathing deeply and as though you were really relaxed, but at the same time it feels

like somebody's choking you. So it's it's a strange place to be. You've got to stay on your back. It's a big ordeal to change position. I don't sleep on my back, so it's it was not a for me, not very conducive to sleeping, but for someone you know, and I've read memoirs of people who'd spent a lot of time in an iron lung, and I expected a description of panic, claustrophobia, anguish, but the description of being

put into an iron lung across the board. People would describe this tremendous relief and relaxation to be able suddenly to breathe calmly and deeply when they'd been struggling to get enough oxygen to live, a very different experience than a ventilator that's pushing air down into the lungs.

by blowing it through. I spoke to a doctor Bartlett at the Extra Corporeal Life Support Laboratory said, yeah, we tried that. You can sort of blow it through via the stomach and that way this carbon dioxide comes out the anus and I'm like, so sort of constantly farting. He goes, yeah, not very.

that could be great. Or if it's a situation, a combat situation where you don't have a ventilator available, you don't have the equipment necessary just to get some oxygen in there, so sort of a supplement the anus is happy to provide.

allow waste to come out. And along with this long history of ostomes also of course comes with this long history of stigma and also these myths that just abound when it comes to ostomese, you know, with like Napoleon and so on and so forth. Can you give me just like a little tour through the history of ostomese?

of artificial anus, if you will. And so in seventeen fifty seven there was this surgeon that's basically why not take a hint from nature. What if we were to do this in cases where somebody has a blockage, whether it's a tumor or whatever is going on, and that it's this blockage. They've tried all manner of the usual suspects and breaking up the blockage and it's not working, and they haven't released anything in days or weeks, and they're about to die because it's going to break, it's

gonna pop soon. So they would create an opening to let stuff come out. The opening is called a stoma, and today that is still done, not so much for blockages, although for that as well, but with very serious cases of inflammatory bowel disease crones or colitis things get really bad. You can put an opening and a pouch.

I just put an empty one on there. I'm like, this isn't bad. But anyway, depending on where your stoma is, that determines what kind of pouch you might wear. There's some that are have to be changed more often because the material is more liquid higher up a small intestine, further down it's more solid. There's various options, big or smaller, two part, one part, just depending on what you need.

Then there's you can sort of fart with them. There's venting if I just like poke a little whole little venting device because you don't want to have a blowout as they call it. So there are like a thousand different pouches and systems for oustumates. And it was, you know, there was a really fun event. Everybody was. You know, this woman when I was using my empathy pouch, I just sort of grabbed this one. She goes, oh, that's a really large pouch. That's just very unsexy. Let me

show you my pouch. See this, This is like, you know, and I changed it three or four times a day, and you know, everybody's had this kind of what are you wearing red carpet buzz? You know, it was fabulous. It was just very fun. And the more we can talk about these things, the less there's a stigma. There's been a lot of good progress made, I think via TikTok and people with ostomies just saying hey, this is

how it works. Here's my pouch, here's how I changed, here's you know, just sort of saying here you go this.

enterprising plastic surgeons gaze happened to land on. Some took their inspiration in the kitchen olive oil, vegetable oil, some in the barnyard goat's milk, cow collagen, pig collagen, or the forest beeswax, tree resin derivatives. Others in the supply rooms of industry paraffin, petroleum, jelly, various glues and polymers. They were sticking anything in there.

it on the sides in the back. So you can take a certain percentage of these follicles and move them up top, and they'll retain the characteristics of their homeland, so they won't be hair that responds to testosterone falls out. So you take a couple thousand hairs from back here and from the sides, and you put it up top, and because of donor dominance, it won't fall out, won't be hair that falls out. And so I was at a hair transplant clinic because of another chapter that had

to do with growing follicles from stem cells. So while I was there, I said, will you can you transplant a couple of hairs from the back of my head to my leg because I wanted by the time I went on book tour, I wanted to have a couple of long, luxuriant hair screwing on my legs so i'd have this demons that I could show people. Look, this is donor dominance. These hairs came from the back of my head. Unfortunately they didn't take The legs get a lot less blood than the head. The scalp gets a

very robust blood supply. On the calf not so much. So I'm sad to say I don't have long, luxuriant leg hair growing from the spot where they transplanted a couple follicles.

in the way is not a will. It's not a lack of skill, it's not knowledge, but it's our immune system that seems to be like this kind of unexpected antagonist that prevents us from achieving all that we want to and replacing whatever body part we you know, have our mindset on. What are people working on to solve the issue of rejection while also not destroying our immune system?

these various components. There's just a lot going on to upset the immune system and to create a reaction, an immune reaction and a rejection. So and that's been in issues. There there are folks who've had a face transplant and now it's breaking down. It's not working as well, it's not supple it's whatever's going on in addition to rejection

episodes and all the issues of immunosuppression. They're going to need a second face or hands, or there's folks who are having hands removed just because the immunosuppression that's necessary to keep the body from rejecting it. It's too problematic. So you know what could be done. There was some work being done with taking some of the donors marrow which has components of the immune system, so you would sort of donate that along with the part being donated.

I don't you know, but you know that was going on. This was back when I reported grunt, which you know, around twenty sixteen, I think they were just doing a lot of these, you know, composite tissue transplants the hands, the arms, the faces, and it's kind of they've backed off of it just it's been very problematic. Even with that marrow I don't remember the name exactly of the technique, but where you take a little bit of marrow from

the donor. There's hope that in the future you could genetically, I'm not sure how, but you would get the organ itself to secrete an immunosuppressive protein, so it would have you'd have localized immunosuppression, so you wouldn't have to tamp down the whole body immune system. You could just get the organ to do it itself. That you know is

in the future. In terms of stem cells, you know, right now, there are treatments where you can take somebody's blood, you can regress it to its very early state where it's called plury potency, and then instruct it to become a kind of cell, say a dopamine producing neuron, you know, for somebody with Parkinson's. But that's a bespoke process, so it's you've got to take it's time consuming and very expensive. It has to be the person's own cells, otherwise the

body will destroy them. But if you could create what's called stealth cells where they evade the immune system, then you could just buy plury potent cells off the shelf kind of and instruct them to become what you want. So so that would be terrific, But that's not You're talking about cells that may replicate and do what they want that evade the immune system. So that's a scary thing.

The f is rightfully concerned about that. So you know, those are two directions things are going, but not quite there yet.

It's a really promising area of research. And that's one thing that I really appreciated about your book, and how all of these areas we've made progress in and progress in one area also means progress in all of these other areas as well.

government funding. So that's been you know, I have an epilogue in the book because the book was I was going to the you know, into production just as the DOGE cuts were happening, and we so we added an epilogue about that. And it's really sad. Yeah.

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