- Do we wanna get into that really quickly?

Sure.

Well, okay.

So in, in essence, this would, this would be when you, would, you take an animal, a pig say, and you would, you would do a genetic edit so that it's not gonna grow a kidney.

And now you introduce human pluripotent cells, stem cells, that, that, that would go into that open niche.

You basically created an open niche, right?

- Right.

- And then the human cells are gonna go in there and make a kidney.

So you have a pig growing a literal human kidney.

And the idea, you know, going forward into the future of science fiction, everyone could have their own personal pig, like, you know, like a car in the backyard for spare parts.

Like you've got a pig that's growing, a bunch of spare organs for you, should you ever need one.

- Welcome to Forum, I'm Mina Kim.

What do frog skin, polyester hair and pig kidneys have in common?

They've all been used to try to replace our remarkably complex body parts science writer Mary Roach, bestselling author of Stiff and Fuzz, has been exploring human's relentless quest to recreate parts of the human anatomy and how astonishingly far we've come, as well as the difficult questions that arise as the science evolves.

Her new book coming out tomorrow is called "Replaceable You: Adventures in Human Anatomy."

Mary Roach, welcome to Forum.

- Thank you so much, Mina.

- Your book is a great reminder that we have been on this medical journey of body part replacement for a long time, hundreds of years in the case of teeth.

And I was wondering if you could talk about what you learned about early dentures and what they were like.

- Oh, sure.

Yeah.

Early dentures, you did not want to have a pair of early dentures.

There were a number of technologies, one of the most gruesome, not used for a long time.

This was 1800s France.

It was called floating teeth, where there were actually piercings in the gum.

And the uppers would be suspended from, from these wires through the gums.

So that didn't last long.

Around the George Washington era, we had a uppers and lowers would be attached with a, a coil like they were spring loaded.

So you'd have the, the spring between the uppers and lowers kind of pushing the uppers, holding them in place.

But the problem for George Washington, as he explained it, was that it also tended to push the denture out of the mouth.

So when you look, this, for me, when I look at a dollar bill and when I look at George Washington portraits, now, I, I, I kind of feel like you can see he's kind of trying to hold his dentures in place.

Like they're kind of coming out and he had this kind of stiff grim look.

And, and now I understand what he was going through.

- Yeah.

I mean, I can understand what a lot of people in the Victorian era were going through because a lot of Victorians lack teeth.

Yes.

But what I was so struck by was that, you know, in the mid 20th century, people were choosing to pull out their healthy teeth.

Why?

- Yeah.

That was amazing to me.

I had heard somewhere this term matrimonial teeth, this, this notion that when a, a bride got married, one of the bridal presents was to have all of her teeth pulled so that she could have, she'd be fitted with dentures, you know, that she would look beautiful for the photograph.

Also it would be cheaper because you have them all done at once and then that's the end of it.

Which of course isn't true.

If you get dentures, your the bone starts to resorb.

You'd have to be refitted at a certain point.

But anyway, and I thought, did this, how, how frequently did this really happen?

And I came across this Reddit thread where somebody asked that very question like, was it really true that this was a bridal present that you would have all your teeth pulled like forties, fifties, sixties, and a thousand people had answered saying, yeah, my grandma, my grandfather, my dad had this done.

There was a reference to an interview, Terry Gross on Fresh Air had spoken to Paul McCartney who said, yeah, my dad said when I turned 21, you oughta go in, have them all pulled, get some dentures.

And I actually found that that interview, it's, that is, that is in fact true.

It was a thing, it was a fad.

It was what you did.

That's the way people explained it in, in their responses to this question.

Like, no, it's just, it was just all the rage.

And I felt so bad for these people.

'cause at that time, I mean, nowadays you can have dental plates actually that click into some implants that are screwed into the bone.

And so they, they do stay put and they do allow you to chew.

But the dentures in that era, you know, they were poly gripped in place, then they did, they'd slip and slide.

People were embarrassed.

They didn't feel comfortable kissing or laughing and, and it wasn't a good replacement at all.

And it was kind of amazing the number of people that decided to do that.

- Yeah.

You mused whether they were succumbing to the lure of progress, I think was the way that you would put it.

- Yeah.

Yeah.

It seemed to me that there was, there is this kind of, kind of delightful hopeful attitude that people have that something new that's invented and it's science and it's going to be better.

And, and often it is, but it's rarely as good as what you have.

I mean, my dad, he, my dad was, I was gonna say my dad's British, and that's a, that's that horrible two, that dental stereotype.

Okay.

It doesn't matter that he was British, he was raised here.

He came over here as a teenager.

So anyway, but my dad lost all his molars.

He was 65 when I was born.

So I always knew him as this guy who chewed with his front teeth.

He never wanted to get dentures, he didn't wanna get the remaining teeth.

He had all of his, you know, his front, his incisors all in place.

So he kind of, like, my brother would use the verb, he kind of beavered his food.

But, but I now look back and I think, well, you were smart because, you know, you, you, you, I'd see him eat.

There was nothing that man couldn't eat and he didn't have to worry about his dentures slipping or or smelling or any of the things that those old style dentures used to do.

- Yeah.

We actually already have a listener comment about how this story is resonating with them, the listener writes, my grandmother in Greece had all her teeth removed when she was in her forties on advice that it would help with her headaches.

It didn't.

And my father tells me she was deeply sad about it until the end of her life.

He said her original teeth were beautiful.

Let me invite more listeners to join the conversation.

Have you ever had a body part replaced?

Hip joints, dental implants, a new organ maybe?

What questions do you have about how far along we are with body part replacement and have you ever struggled with a decision to replace a body part and why?

You can tell us by emailing forum@kqed.org, finding us on our social channels, discord, blue sky, Facebook, Instagram, and threads at KQED Forum or by calling (866) 733-6786.

Again, that's (866) 733-6786.

I loved also the detail that you added that, you know, around, you know, the mid 20th century was when the $6 million man came out this idea, right, that like he was gonna be stronger, better, and faster, you know, as a result of replacing his parts into something that science came up with.

- Yeah, yeah.

I remember that.

I saw that show and yeah, you'd see him on the, the treadmill running and he also, he had the bionic eye and, and, and I think it, it would beep when he kind of queued it up and I'm like, that's an annoying feature.

You didn't, you didn't need to have it beep.

- Exactly why we have learned that often the artificial part does not function as well as the original.

And I'm reminded Mary of a conversation you had with a surgeon named Jeremy Goverman who told you that he really didn't think we can replace the human body, right, because it is so - yeah.

Miraculous in its complexity and architecture.

Yeah.

Yeah.

I think we've come such a long way in replacing parts that are failing, that are broken, that are missing.

But when it comes to matching, what we started out with, I don't think we're there yet.

I tried to find is there any part of the human that we can do that with?

And I thought, okay, let's get really simple.

And I thought, okay, tears, artificial tears, they're pretty good.

Right.

And I call, I found this, I looked up, I looked on the internet "Tear Lab" and I thought, ah, there's gonna be a lab where they're like bringing people in and having them, showing them sad movies and making them cry.

And it's gonna be, there's gonna be a big statue of an eye or a tear out front.

I had this whole vision of what I was gonna experience.

In fact, it's, it's a, it's just a tabletop device for quantifying dry eye.

But the guy who invented it knows a lot about tears.

And I'm like, okay, help me here.

We've got, we've got a replacement for tears.

Right.

Okay.

So we, we talked for two of the free zoom cycles 'cause I'm too cheap to pay.

Right.

So was it forty-five?

Sounds like 90 minutes.

Five - Minutes, yeah.

- Yeah.

So before I found out, I'm like, okay, wait, gotta start again.

I'll call you right back.

So, but, but for, it's, in other words, an hour and a half just talking about specifically not the tears that you cry, but the tear film that protects the eye, that, that keeps it lubricated and keeps dangerous things from becoming dangerous infections.

The tear film, it's got this structure, this kind of brush, like almost a scaffold holding the various layers in place so that's there to prevent the evaporation.

There's mucins, which are kind of collecting the debris and like parking it in the corner of the eye.

So that kind of sleep snot that you wake up and here that stuff is like, you can thank mucin.

Lubricin is this amazing lubricating fluid.

And I'm like, okay, all right.

Get it.

I get it.

We have not figured out how to replace the human tear film.

- Yeah.

- Not even that.

I love when you were like salt water with a layer of oil to keep from, from a how hard could that be?

- Exactly.

Exactly.

And then I said, well, so those products that are out there, he goes, well, you know, some of those will work for an hour or two, but kind of in a way they're washing away some of that good stuff.

- Yeah.

Like, - Yay.

Nothing is simple.

- Yeah.

But I think you were also alluding to this too, while it is pretty impossible to replace the human body, you know, in all of its complexity, it really is worth giving it, giving it a try for all the ways that we have found it can help people.

And, and you were getting to this, but I'm also wondering if you could just remind us, you know, some of the problems that we have done a pretty good job of trying to solve by replacing body parts that are really life changing for people.

- Sure.

Well, yeah.

If you, if you look at cataract surgery, we are now- I just, a friend of mine just had both eyes done at once.

I mean, it's become so reliable, safe, fast, effective that it's kind of a, you do it in an afternoon and then you, you know, you're seeing things in this amazing new way that same day.

But that began, you know, thousands of ago, what was done.

'cause the cataract is just, it is the lens itself, which has become clouded.

And it, and it at the end point just isn't letting light through at all.

So what used to be done, it's the most common form of preventable blindness, what used to be done back in the day, no anesthesia, just sharp stick into the eye, kind of piercing the lens and pushing it down to the bottom of the eye.

And, and this is a quote from like a 12th century medical manual.

You would hold it down for four or five.

Pater Nosters, Our Fathers, which seemed to be an appropriate thing to be using to count by the, to count the time.

So you would just like, hold it down out of the way.

And now the light could come in and even though things were not focused, at least you could see colors and shapes and probably could, I mean, I'm really nearsighted.

They probably ended up kind of like me.

But in, I mean, it's the shape, the lens itself provides about a third of the focusing ability.

It's the, you know, the shape of the eye itself.

And so they still had that, so patients would be able to see it's just, you know, there are a lot of infection and, you know, other bad things happening from the stick going in the eye.

- We're talking about the quest to recreate and replace our human anatomy with Mary Roach.

More after the break.

I'm Mina Kim Welcome back to Forum.

I'm Mina Kim.

From prosthetic limbs to principle organs.

We're talking about the history, science and complexities of human body part replacement with Mary Roach, whose latest book is "Replaceable You: Adventures in Human Anatomy."

And you might know her from her previous books, including "Grunt," "Stiff," "Bonk" and "Fuzz."

And you, our listeners are joining the conversation.

Have you ever had a body part replaced, a hip joint, a dental implant, a new organ?

How does the replacement compare to the original?

And what questions do you have about how far along we are with body part replacement?

You can tell us by calling (866) 733-6786.

(866) 733-6786, by finding us on discord, blue sky, Facebook, Instagram, or threads at KQED Forum or by emailing forum@kqed.org.

Maybe you've struggled with a decision to replace a body part as well.

You can tell us why.

Let me go to caller Vincent in Sacramento.

Hi Vincent.

You're on.

- Good morning ladies.

Thank you for taking my call.

So yeah, I had total shoulder replacement surgery exactly two months ago today.

- Oh, wow.

- So I, I have a brand new shoulder.

Originally, it was about 40 years ago when I was a paratrooper in Alaska.

I dislocated it and it kept dislocating.

So they did a, a surgery way back then where they just filled it in, so, so it wouldn't pop out.

And then 40 years in the future it started getting really bad and hurting.

And they said I was a good candidate for total shoulder replacement.

And, and I'd never looked at it on YouTube or anything, but the doctor explained what he did and then I looked at it afterwards and it was absolutely gnarly, horrifying.

But it, but it's, it's been two months and it's, it's working out really good.

I'm going through physical therapy and yeah.

Yeah, I - I'm so glad to hear that it's working out so well for you, Vincent.

You know, Mary, this is making me think about, we were talking about a lot of the ways that some of the replacements that we've come up with haven't been great.

But it was really interesting when you were talking about, you know, body parts that we've been able to replace successfully and, and also the realm of prosthetics that it's possible to really entertain the question of, you know, whether or not something has gotten so advanced that people should choose them over their own limbs.

- Yeah.

Yeah.

I'm glad to hear that story, Vincent.

That's, that's amazing.

You know, that's it.

I think a shoulder replacement, I didn't cover this in the book, but were you actually sitting up to have it done?

Oh, I think, oh, it's gone.

Okay.

Travis Air Force Base.

Oh, there he is.

- And they had, yeah.

Oh, I'm sorry.

Yeah, I was, they they did it over at Travis Air Force Base and they had me sitting up.

- Yeah.

- And, you know, and then I went, then I went under, and I think it took about two hours, two and a half hours to do the whole surgery.

Yeah.

And then I came back to the post operation about a week later and they explained what, what they did, and I looked it up online and watched it on YouTube and it was, but - Yeah, - But, but, and it's supposed to, it's supposed to be good for like another 10 years.

But one thing I wanted to bring up was I did have problems deciding to do it.

I've had a lot of surgeries in 64 years and I was, I really didn't want to go through the surgery, but I was waking up in the middle of the night with really bad arthritis and, and they said they dug a bunch of arthritis out too.

So I'm glad I did it, but, and it's supposed to be good for like another 10 years or so.

- Yeah.

Yeah, that sounds right.

It is gnarly.

I will say I spent time in an operating room where I think it was 10 operations, five hips in one OR, and five knees in the other.

The surgeon crossing back and forth.

It was amazing how quickly and, and the operations, the cut time was like, which is from skin open to skin closed is about an hour.

So it's gotten, I mean, a shoulder's a little more complicated, but, and I was talking to the anesthesiologist and, and he said, he said at one point, you know, because we do an epidural, a shot to the base of the spine to kind of numb the low, the area.

He said, you could be awake.

And we've had patients request that to be awake.

He said, but there's a lot of sawing and hammering sounds that you probably don't want to hear.

And I can confirm that that is, to me, that was the gnarliest.

Yeah.

I mean, I - Couldn't - Really see that well into the incision, but I could hear it all.

And it's, and it is a sim, my husband works in the wood shop with power tools and I know these sounds, and those are, you know, that's a, there's a, you know, it's a electric saw and there's something called a reamer, and then there's the surgical mallet, which you think, oh, it's gonna be really high tech.

No, it's a mallet going, it sounds like you're putting in a tent stake.

And that's to stick the, you know, the implant for the hip replacement down into the femur to hammer it down in.

So it's an amazing procedure and it's come such a long way.

But yeah, it still sounds like, you know, you're working on a car in the garage.

- Yeah.

Your description of that was so funny.

Yeah.

So that's joint replacement.

You also tell this story of Judy, who basically does elective amputation, right?

She chooses to have her foot amputated and while, you know, the joint replacements are more commonplace, it sounded like she had a really hard time getting a surgeon who'd be willing to do the, the foot amputation.

Can you just tell us Judy's story actually?

And then Yeah, - Yeah.

Judy was one of the, my conversation with her is one of the things that steered me down this path for this book.

She had written to me, she's a reader and she'd said, she'd written to me and said, I think for your next book you should write about professional football, referees.

And that, you know, didn't resonate with me quite as well as it might 'cause I don't watch football.

But anyway, we corresponded and she happened to mention that she was an amputee specifically.

She said an elective amputee.

And that's a person who didn't have to have the foot removed, the lower leg removed, because it was, it was healthy, it had a blood supply, she could walk on it, but she couldn't walk well.

She'd had spina bifida, there'd been issues with her spinal cord that had sort of affected the way her foot, her foot was essentially twisted.

She couldn't run, she couldn't hike the way she, she just couldn't move the way she wanted to.

And she would see people hiking, running, jogging, whatever, just going about their lives with a lower limb prosthetic.

And she said, well, you know, she's like, why can't I have that?

You know, your hip wears out, you get a hip replacement, why can't I have this?

And she contacted quite a few surgeons over the years who wouldn't do it.

And there's a number of reasons why surgeons, you know, might be hesitant to do that.

She said, they kept saying to me, it's a healthy foot.

And she'd say, yeah, but I can't walk on it.

And eventually she did find someone to amputate and she was much happier.

But it wasn't, it was interesting, you know, we have this kind of bias for wholeness in a way.

And I, I mean, there's various reasons why a surgeon, you know, maybe liability.

What if there were phantom pain?

How do you get insurance to cover it?

There definitely are reasons why a surgeon or just, I don't do a lot of amputations and I'm not comfortable with it.

Plenty of reasons why the surgeons may have been saying no.

But there is this kind of desire to like, well, maybe one more surgery, maybe we can fix it.

Maybe we can get you back to where you were.

And this, and behind that I think is this kind of like sense of like, it's better to be a whole, you know, don't, don't remove something that you can't put back.

You know, and she knew that that wasn't the case, but I think she was working against that kind of bias too.

- Yeah.

And, and you talked with people, I think it was Ezra Frech was one of them about - Yes.

- How that bias could operate in the sense of, okay, just because I have a prosthetic, I'm not whole kind of feeling, you know?

- Yeah.

Even the word, I mean, Ezra Frech, is, for people who are not familiar with him, he's a Paralympian.

And in the last Paralympics, he won gold in a high jump and another event that I'm now forgetting, but he's a tremendous athlete.

Look him up on TikTok or YouTube.

But I didn't know who he was.

I was at the annual convention of the Amputee Coalition, and I was speaking with his father who helps people get back into athletics after an amputation.

And he came up, Ezra came up, and we were chatting and he has, you know, an amputation mid thigh, and surgery on, he was, he was born with various disabilities, various dis you know, malformed limbs.

And I said to him, oh, can you run?

Like, I had just looked at him because he had this, you know, above the knee amputation.

I just assumed that, you know, that he was seriously disabled.

Well, I'm, you know, compare me to Ezra Frech, I'm the disabled person.

I mean, like, you look at what he can do, how he can run, how he can jump out.

I mean, he's an unbelievable athlete, but, so the word disabled is a funny, it's a funny thing.

You know, I'm very, very nearsighted.

I'm legally blind without my contacts.

So if I didn't have my contacts, I'd be disabled.

But it's a, yeah, it's, and he took it so well.

He is like, can I run?

I can run.

Yes.

Yeah, I, yeah, yeah, I can.

- I'm sure he's used to it.

Actually.

Do you just wanna take a second to talk about how far we have come with a prosthetics?

I was pretty amazed at just how advanced some feet prosthetics are now in reading Judy's story.

- Yeah, yeah.

Very much.

Yeah.

There are now the, particularly for lower limb amputations, there are micro-processors and you know, sort of hidden, not hidden, but there's, like, they're built in kind of looks like a, you have a very, like a metal calf muscle kind of there.

They look kind of cool and they sense when you're about to fall and they help you and they help prevent that.

There's the other advancement that's getting a lot of attention is called osteointegration.

And that's a process whereby the prosthetic, instead of you having a socket that compresses your residual limb, you would actually, it would screw into the bone similar to a dental implant.

And in fact, the person who pioneered osteointegration is the person who pioneered dental implants.

And, and it's so much better when it works and when there's no infection and the infection part of it is still something that needs to be worked out.

But when it works, suddenly the person can sense what kind of terrain they're walking on.

Are they walking on, you know, is it grass, is it pavement?

Are they stepping on someone's foot?

Ezra Frech always talked about, I'm always looking down to make sure I'm not standing on someone's foot.

So there's this amazing feedback and you, it just, you're moving more the way you move with a natural limb.

So that's exciting.

It's very, that's a very exciting development.

There, there have been issues, depending, there's two different processes and the, you know, the, you're, you're trying to get this, you, you've got this, it's a surgical procedure that, and not completely closed off so and so bacteria can get in.

It's, you know, if you look at like a deer with antlers, that's, if we could only, if we could figure out how that works because deer don't get infections, but it, you know, there's a bone kind of protruding through the skin and yet it doesn't get infected, but it does, sometimes the rates have been a little high.

And that's, that's been keeping people from - Judy, Judy thought it, I mean, she has a friend who went through it in Australia and is still in a wheelchair because there's been a number of repetitive infections.

But for the people for whom it works, it's light years better for them.

- How accessible are these kinds of body part replacements?

I'm just thinking generally it must be very expensive and I'm just wondering where, where healthcare is.

- Right, right.

I believe one of the osteointegration companies did get approval.

But it is a very expensive procedure.

And at what point does insurance cover it?

That's, that's the other question.

And for some of the upper limb, the arm prosthesis that have, you know, the articulated fingers and, and you kind, the kind of bionic looking, very cyber looking limbs, those are very expensive.

You know, 10,000 and up and insurance doesn't cover them.

So that's two things working against them.

Also they're, for people who've tried them, they're very heavy.

They have to be charged, you know, it's battery, battery powered and it can be uncomfortable, that much weight.

So I mean, I, I I feel like it's just in its infancy and yes, in decades to come, it will be a lot better.

So those are, you know, they look cool online, but sometimes, you know, the mental energy to kind of, 'cause it's really you're sending an impulse the same way that you do now with a, you know, with a natural hand.

You're, it's this impulse to open and close and it's seamless and instantaneous.

But some of the limbs that are, are available now, you're kind of toggling through a menu of grips.

I was at the Amputee Coalition with Judy, the, the woman with that I mentioned earlier.

And we walked by, there were very few of those products there, there was one where they showed a photograph of one of those bionic hands kind of ho holding a straw raspberry, which was, of course, you know, that's a very delicate fruit berry.

And she looked over at it.

She goes, yeah, are you gonna spend 20 seconds kind of manipulating the grip to the point where you want it?

Or are you gonna reach over with your other hand and pick it up and put it in your mouth?

So that's kind of where things are at.

It's very exciting and they're very cool.

And it, like all of this, you know, if you look at cataract surgery in the 1960s, it was a, you were in the hospital for days.

Lying on your back was sandbags on either side of your head.

It was a big incision.

There was stitches, it was a big deal.

But it was also exciting.

And it was the birth of this technique that now means people can have perfect, you know, vision.

And where before they were unable to drive at night.

And so anyway, it's a, it's a long process.

The first hip replacement was 1938, you know, so, so these things, you know, to get to the point where everybody's having it done, which is exciting, it just, it takes a while to get there.

And I think that these sorts of prosthetic limbs are, are, are getting there.

- Yeah.

We're talking about where we are with human body part replacement, where the science is, and also the kinds of interesting, difficult, unexpected questions that can come up as the science evolves.

Anne writes, I'm a recipient of bilateral cochlear implants.

They're pretty amazing.

Everything sounds normal.

I can no longer detect tones and semitones though, so my music appreciation is sadly, almost non-existent.

I have participated in several music and sound studies at UCSF where researchers are trying to overcome one of the last challenges, cochlear implants recipients face.

Hopefully there'll be a solution for me at some point.

I'm extremely grateful to those who went before me and had implants with only two channels.

Today's have at least 22.

Cochlear implants are one of modern medicine's miracles.

And Cole writes, my mom had problems with her hip all her life and got it replaced in her forties, which is rare.

She had less pain and better mobility.

But eight years later, the hip was recalled, like a faulty car part.

They were leeching cobalt and chromium into patients bloodstream.

So she had to get a second replacement.

Let me go to Caroline in Oakland.

Hi Caroline.

You're on.

- Hi.

I'm also wondering about hip replacements.

It, I don't know if it's still true, but people used to be told not to have hip replacements too soon, like in their fifties or sixties because they'd have to be done over again.

They didn't last for very long.

Yes.

And I know, I think they're all titanium now.

Is that expected to last longer?

- Yeah, you're, you're right.

They would, there was this feeling that you didn't want the hip to, you didn't want the person to outlive the hip or there was, you would, you would, you would wait till the person was, you know, in their sixties, seventies, eighties.

So that way you wouldn't need to put them through a second procedure, if that makes sense.

So yes, that was the case and, but not so much now.

There were definitely issues with, it was called metal on metal, the early metal on metal.

So, you know, you have, it's a ball and socket replacement and, and you have the cap and then the ball of the upper part of the femur.

And when they're rubbing together over time, there were some wear debris, some little bits, tiny bits and pieces of metal that would cause this inflammatory reaction, which caused the, the, the joint would have to be the, the person would have to have the implant removed and replaced.

And that is much less common now.

- Yeah.

- There are better metals being used.

I mean, there are still metal on metal, but it's often a kind of a, it's like called high molecular weight polyethylene for the, the socket part of it.

And then the there's a really good friction between the two.

But the materials part of it is, has been tough to work out because of that, either the the ball was wearing out the, the socket, you know, wearing that down and, and would need to be replaced.

And also that yeah, that the little bits of metal were causing some horrible side effects.

- Yeah.

Actually you're making me think of, you know, so many examples of how the body can ultimately reject something.

And I'm gonna ask you more about that after the break.

We're talking with Mary Roach.

Stay with us.

You're listening to Forum.

I'm Mina Kim.

We're talking about the science of replacement body parts from hip replacements to prosthetic limbs to organs as well.

Science writer Mary Roach.

Her latest book is "Replaceable You: Adventures in Human Anatomy."

And she's the bestselling author of "Fuzz" and "Stiff."

And listeners, have you ever had a body part replaced, like a hip joint or a dental implant or even a new organ?

How does the replacement compare?

Did you ever struggle with the decision to replace a body part and what questions do you have about how far along we are with body part replacement?

Jennifer writes, I had eye lens replacement surgery a couple years ago, and I'm very happy with the results.

Colors are brighter, my astigmatism is gone, and I swear I can see from here to New Jersey amazingly fast and pain-free.

The worst part was having to forego contacts for a month pre-surgery.

Joel writes, my mother died of cancer, which started out in her bladder.

She didn't have a great will to live with her bladder removed, and I can't blame her.

Today, there are bladder replacements using a person's own intestine lining to form a new bladder.

This is a tremendous advancement.

Joel, thanks for telling us about her.

You know, so one of the things that we started out talking about were teeth and and teeth replacement, which has a long history of trial and error.

And then we were hearing, you know, Caroline talking about what we learned about, you know, metal on metal hip replacement.

And now that they're titanium they're expected to last longer.

It really is such a process of learning.

But one of the ones that I found so fascinating in your book, Mary, was what we've learned about skin grafting and skin replacement.

Because I was pretty shocked to learn just what different types of animal skin we tried for so long, like frog skin and, and even like tilapia fish.

- Yeah.

There, it was quite a menagerie of the technical term is zoografting or xenografting when you take another species' skin.

And yeah, I remember reading with these, all these articles from the 1800s and early 1900s about taking skin from like the chicken because the chicken, you know, under the wing you have that kind of, that there's not a lot of fat there.

It's just sort of that skin where the, at the kind of the joint there and like that, that skin, frog skin became very popular.

There were a lot of popular press stories about people becoming part frog.

And I was like, but wait a minute, did they really become part frog?

And I, I ended up spending time at the Mass general Massachusetts General Hospital Sumner Redstone Burn Unit.

And one of the questions I had was, so why wouldn't we have, the humans, Why wouldn't they have rejected the, the pieces of chicken skin or frog skin?

Yeah.

Did they really become part frog?

And what the surgeon said, Jeremy Goverman, he said one of the things that happens with a severe burn, a third degree burn is that the immune system is suppressed.

The immune system is not doing its job.

So in fact, it was kind of the, the body was kind of accepting of whatever you put on.

But you know, essentially all of these things, the, the chicken, the frog that nowadays, the cadaver skin.

tilapia, that's a recent one.

Cod skin is used.

They're essentially bio dressings in a way.

They're, they're protective and they protect the wound as the person's healing, but eventually they slough off or they're pulled off and the person's own skin is used because as the immune system gets back online, it doesn't want frog skin.

It just, it doesn't want it.

Yeah.

So, those techniques, you know, while they seem kind of outlandish, you know, cod skin is still used, but the question is, you know, for especially for like a, a second degree burn, which you know, heals fairly well on its own, you know, those, do we really need to be spending so much money on these kind of very, very fancy, you know, there's some that are like embryonic or they're umbilical or they're fore skin or there's all these kind of skin substitutes that get a lot of attention, but depending on whom you speak to, just any kind of bio cadaver skin will work really well too.

And it's mostly just protecting it.

There's, you know, things like Mepilex, which is an antibacterial kind of foam dressing, which also works really well.

And the surgeon said to me, Mepilex will cost you $10.

Cod skin will cost you a thousand.

You know, so there're differing opinions on that.

But a lot of Medicare dollars go toward those skin substitutes, you know, those, those things when depending on what kind of wound it is, you know, second degree burn, you know, you're probably fine with something a little less expensive.

But it, it was an interesting era certainly to look through the medical journals and see all of the, you know, I imagine 'cause the guy who one the paper that I read was, it was, he was, it was World War I, he was in France and there was, you know, as there was like, he, as he put out a lot of supply and demand for frogs in the region that he was in, I kind of imagined him, you know, going in and going like, Hey chef, I can take those torsos off your hands.

- Yeah.

Well, how, how have surgeons and specialists grappled with the, the challenge of, you know, human body rejected animal tissue and organs when we are turning more to animals for our organs?

- Yes.

Xenotransplantation.

And we're not talking about skin here, but organs, - No.

Yeah.

Organs, - Yeah, organs, kidneys and hearts.

That's very exciting right now.

- Yeah.

- There is a, there's one, I mean, right now the, the, the organs themselves have, they don't have FDA approval yet, but there's, eGenesis is starting a, a trial right now of, I believe it's a kidney, a number, have a number of hearts and kidneys have from pigs, gene edited pigs, have been transplanted, transplanted into patients over the past couple of years.

And for a while the results didn't look great, because the patients would live about two months, generally speaking.

But the thing to bear in mind is that those patients were very, very ill.

The reason they were able to receive these experimental organs is that they weren't going to live long.

So it was a compassionate use exemption.

That's why the FDA was like, okay, go ahead and try it - Because there's no other solution.

They're, they're too far down the list.

They're too sick to, to be getting a human organ.

So those weren't ideal patients to look at how well does this work.

There's a patient now, Tim Andrews, who I think it's eight months, he's had this pig kidney and he's doing well as far as I know, and the trials are underway.

So that, that's exciting.

And even, you know, even if it only buys someone a year, that may be enough time for them to make their way up the waiting list and receive a human organ.

So, you know, it's, it is exciting.

And, and the that it is amazing because if you look at an unedited pig heart, say that, and you were to put it in someone, the body just goes crazy.

The body, it's called a hyperacute rejection.

And it just like attacks it and it starts to turn black and just, it's destroyed because it's a, it's a very foreign, it's like the body's like, what the heck?

Get that outta here.

So, you know, the edits have, you know, have created a replacement that's, you know, you, you still need immunosuppression, but closer to what you would need if you received a human - 'cause you can essentially put, like, human cells as part of the growth of the pig, of the organ in the pig?

Am I, am I understanding correctly?

Oh, well, it, the pig has been genetically from the beginning It's a gene edited on the pig so that they've knocked out, there's this thing, the alpha gal protein, which is a kind of like a red flag of otherness, you know, that the body's like, whoa.

So if you, if you knock that out using CRISPR using gene edits, I see you.

If you get rid of that, then you're kind of fooling the body.

It's like, oh, there's, it's not that different.

You know, move along.

I see.

Not a big deal.

- I, I think I might be thinking about - It's still a big deal, but not a huge deal.

Your chapter describing chimerism.

- Yes.

That's a different, that's a different, that's a different.

That's a little sci-fi.

But that is, people are looking into that and that is, do you want to, do we wanna get into that really quickly Sure.

- Well, okay.

So in essence this would, this would be when you, would, you take an animal, a pig say, and you would, you would do a genetic edit so that it's not gonna grow a kidney and now you introduce human pluripotent cells, stem cells, that, that, that would go into that open niche.

You basically created an open niche, right?

- Right.

- And then the human cells are gonna go in there and make a kidney.

So you have a pig growing a literal human kidney.

And the idea, you know, going forward into the future of science fiction, everyone could have their own personal pig like, you know, like a car in the backyard for spare parts.

Like you've got a pig that's growing a bunch of spare organs for you should you ever need one.

Which is very, very bizarre to think about, but apparently there is a, a mouse that grew a rat kidney or vice versa, right?

I can't remember.

It's in the book.

But anyway, it's, it's very much in the beginnings of research and there's ethical issues.

'cause sometimes some of the cells don't, aren't restricted just to that organ.

They may, if they end up in the brain and you now you've, you're suddenly you have a, a pig that's developing a brain that's closer to a human.

And now what are the moral consequences of that?

And anyway, that's chimerism.

- Yeah.

- In a very simplified, I mean, it's beyond me, you know, it's like, what's the line in the Big Lebowski?

You're outta your league, Donny.

It's a little outta my league, Mina.

- Well, this listener writes, no more bacon for me.

Lemme go to Penny in Corona.

Hi Penny.

Join us.

- Hi, I'm, thank you for taking my call.

I have an interesting situation.

Our family, number one has had multiple body replacements, but this one I haven't heard on your program yet today when my son was 16, back in the early 2000s, he and his friend were skateboarding in the house.

Anyway, he lost, he went elbow first through a glass table.

- Oh my gosh.

Completely severed.

Yeah, he could, he's fine now.

But he completely severed his ulnar nerve about an inch or two above his dominant hand elbow.

He had that repaired and the nerve regenerated.

And then he was sent to a plastic surgeon.

Shout out to Dr.

Collina wherever she is at.

But she, she harvested his own tendons from both of his arms and one of his legs and rebuilt his hand.

It, there was like 33 35 incisions in his hand where she removed all the old tendons.

I, to be honest, I don't know, maybe she didn't do that, but she used the tendons that she harvested from his arms and legs to rebuild the use of that hand.

And what was interesting is that he had to go to therapy.

He was 16 years old at the time.

It was the youngest person she had ever worked on, but they had to train his brain to reuse that hand because when they replaced everything, it was completely different than his other hand.

But he did, and he went through therapy.

It was very quick for him.

He, it was completely successful.

And he is in his forties now, if I'm doing the math right.

I'm bad with math.

He's, he's been an artist, an auto mechanic, an electrician.

He modifies cars.

He is a calligrapher.

He does everything with that dominant hand.

Wow.

And, and what's interesting is that his brain, when he picks up a box, let's say his left hand is doing one signal from his brain and his right hand is doing a different signal from his brain.

But it works fine.

And to me that's a miracle.

I don't know how that works.

- Oh, Penny, I'm so glad to hear that happened for him, and thank you so much for sharing that.

And, and I should remind listeners, we're talking with Mary Roach about replaceable body parts.

Her book is "Replaceable You" and you are listening to Forum, I'm Mina Kim.

and that's where everything is really moving, right Mary?

It's really, you know, we've learned that really our own parts and using our own parts to try to create something is best, whether it be skin and I guess in Penny's case, tendons as well.

Right?

It's it's really about regeneration.

- Oh yeah.

If you can, if you can use your own parts, that's, that's an advantage.

And I was impressed in writing this book with the kind of adaptability of the human body to, you know, like there's a procedure where if in cases of cancer or, or as an alternative method with transgender surgery, you can, you can use the part, you can use part of the intestine to create a vagina.

And you, I mean, the intestine gets used, like someone mentioned earlier, the line, an intestinal lining to make a bladder.

The appendix has been recruited for various things.

And I'm just always impressed at the flexibility of the human body.

You, you know, you have this organ that evolved for digestion and now you're asking it to take on a completely new role.

And, and by and large it's, it's kind of like, okay, all right, I'll do my best.

And it's kind, it's, it is amazing.

- Yeah.

- You know, you can take, I remember seeing for a, a prior book, "Grunt," I saw a surgery where to rebuild a urethra, a man's who'd been injured in an IUD explosion, they took a a little piece of the inside of the cheek and they took that and that would roll.

They rolled it up to make the urethra.

And I said, well, why that particular tissue?

And they said, well, it's the inside of the mouth.

So it's evolved to withstand moisture.

It's used to being wet.

So as a urethra that seemed, that was, they're like, let's try it.

And so the, the adaptability of the body and also the creativity of surgeons to just say, you know what?

This might help someone.

Let's try this.

Let's take a little bit of cheek and let's roll it up and put it in.

Hey, look at that.

It works.

I mean, that's an amazing thing.

- It is.

It's an incredible thing.

And, and it's, it's so interesting because in this process of showing just how far we've come in terms of learning and understanding how to replace or come up with effective replacements for body parts, which we've been hearing so many of our listeners share today, it's also just exposed how incredible our bodies are.

Right.

Which is something that you really feel like is important for us to remember.

Why, why so important for us to remember Mary?

- I'm, you know, I've been writing about the human body on and off for years, and I'm always just amazed at, you know, you go through life thinking of yourself kind of as a mind, you know, a person.

But it's, it's very much mind based, you know, and, and we lose sight of the fact that in the background all the time are a thousand amazing, minuscule processes that are all working in harmony to enable us to go through life, not thinking about our bodies.

Not, we don't feel it, we don't know that it's going on.

And so I think that makes us a kind of, we kind of take it for granted, you know, there's all this stuff that's going on.

It's a miracle really.

I mean it's, that sounds cliche, but we lose sight of that.

And every time I do a book like this, I'm, I'm just gobsmacked by all of these processes and how well they work and, and how they enable us to, you know, like your human heart.

You see that in human heart, in a chest.

It, it's very active.

You know, you feel your heartbeat and you think, eh, that's a little lud dub thing.

I dunno, whatever, kind of a subtle movement.

But you see a heart and it is like squirming around in it's little burrow there.

And it, and it does that, you know, day in and day out for, you know, 80, 90, a hundred years without breaking or mostly without breaking down.

And it's, it's just amazing.

- Yeah.

You, you got to see a heart, like outside the body pulsing.

Yeah.

And that was incredible description.

So, you know, we just have 30 seconds left, but we've been talking about sort of the trajectory of these advancements, and I'm wondering if you're feeling like, you know, how long will it be before we see some of the really incredible ones that people are doing, you know, like this chimerism, like the 3D printing that people are attempting and so on.

Like, do you feel like we are on an accelerated pace now?

Or, or do you think that these advances we shouldn't get ahead of ourselves?

Like these advances are gonna take a long time?

- Well, I think, you know, things are in one sense happening lightning speed.

Look at crispr, what, 2012 and already people are benefiting from gene therapy and that's amazing.

But just, you know, keeping in mind the, the approval process, you know, that's 10 years, $10 million.

So it takes time.

But yes, it's happening fast.

- Mary Roach, the book is "Replaceable You."

Thank you.

And thank you listeners.

You've been listening to Forum, I'm Mina Kim