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IRA FLATOW, host:

From NPR News in New York, this is TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow.

(Soundbite of “The Six Million Dollar Man”)

Unidentified Announcer: Gentlemen, we can rebuild him. We have the technology. We have the capability to make the world's first bionic man.

FLATOW: Remember Steve Austin, the six million dollar man? This hour we're going to look at bionics and tissue engineering. Now that doctors have created bladders in the laboratory, how close are scientists to producing made-to-order organs or getting limbs to regrow? As for replacing missing body parts with machines, we'll talk with the inventor of a computer-controlled hand that can actually play the piano, and with the creator of a bionic eye. The new six million dollar man, probably more like six billion today, how close are we and is he too expensive? Stay with us.

(Soundbite of music)

FLATOW: This is TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow. This week, doctors announced that they have grown functioning human bladders in the laboratory and have successfully transplanted them into people. The bladders were implanted in seven children who had poorly functioning bladders as a result of birth defects. After receiving their new bladders, all the patients showed improved urinary incontinence. As you might imagine, the success of the first lab-grown organs to be implanted into humans has been hailed as a milestone, and it has many people asking, perhaps yourself, okay, what's next? Hearts, lungs, livers? Will doctors someday be able to make organs to order, for example. You have a bad kidney? Okay, let's order up a replacement kidney for your ailing body, or your aging body, as the baby boomers get older. And why stop at internal organs? How about new arms, or legs, or eyes? And what about mechanical, or bionic parts, like, you know, Steve Austin, to replace the body parts that don't function anymore?

Bionics research is a very, very hot topic. It's underway in labs across the country and this hour, we're going to take a look at the cutting edge of all of this research, and whether anyone can afford all these parts if they are produced and if they're available. Are they going to be too expensive? You know, we talked about the $6 million man? We're talking here the $6 billion man. And so, if you'd like to get in on the conversation, our number is 1-800-989-8255, 1-800-989-TALK. Let me introduce my first guests. Steven Badylak is a research professor in the department of surgery, the University of Pittsburgh. He's also director of the Center for Preclinical Tissue Engineering at the McGowan Institute for Regenerative Medicine. He joins us by phone. Thanks for being with us today, Dr. Badylak.

Dr. STEVEN BADYLAK (Research Professor, Department of Surgery, University of Pittsburgh): Oh, thank you for having me.

FLATOW: You're welcome. Michael Lysaght is a professor of medical science and engineering and the director of the Center for Biomedical Engineering at Brown University in Providence, Rhode Island. He joins us by phone. Thank you for being with us today, Dr. Lysaght.

Dr. MICHAEL LYSAGHT (Professor of Medical Science and Engineering, Brown University): Nice to be here.

FLATOW: Dr. Badylak, tell us about this new bladder. Why is this a breakthrough?

Dr. BADYLAK: Well, what Dr. Atala reported earlier this week is fundamentally a proof of principle, that one can take cells that are harvested from your body, mix them with an appropriate scaffold, do something with them outside the body, and then take them back into the patient to fix a broken body part. A lot of that type of work has been conducted over the past decade in preclinical animal studies. But this is the first report of it being done in humans with long-term (unintelligible). And so, I think, much more than anything else, it's a proof of principle. It gives hope to others in the field that this can really work. And I think it's just the beginning. There are a lot of limitations to it, which we'll probably get into during this hour, but it certainly is a, I would consider it a breakthrough, yes.

FLATOW: You talked about a scaffolding. Can you give us an idea of the technique that was actually used to create the bladder?

Dr. BADYLAK: Sure. What Dr. Atala did was to take a biopsy of the patient's normal bladder tissue and then separate the cells out that make up that particular organ, the urinary bladder. Then, in culture, place these cells on an artificial scaffold. The one that he used in some of his patients is called polylactic glycolic acid, or PLGA for short. The name isn't as important as the fact that it's a synthetic and degradable scaffold. And, alternatively, he could use another scaffold, a biologic scaffold, which would be derived from another human, and just take the scaffolding material, called the extracellular matrix. He can use either of those scaffolds, seed the cells on it, and those are very suitable substrates. And then the cells proliferate and, hopefully, self-assemble into a bladder-like tissue. And then that tissue, once it begins to look enough like a bladder, and have enough mass to be of use to the patient, is then surgically implanted into the patient to fix whatever the defect might be. The limitations of it are that, of course, in culture, it doesn't develop a blood supply or a nerve supply. So that particular aspect of the remodeling is counted on as happening in the patient.

FLATOW: Mmm. So how many organs, whether, you know, you've done this in the bladder, what about other organs like the liver and the kidney? Other organs, are they amenable to this scaffolding, building process and implantation also?

Dr. BADYLAK: Well, theoretically, they are, but practically, there're a lot of limitations. The bladder is, and I use this term relatively, relatively simple compared to say the liver or the kidney, which has more cell types and arranged in a more complex pattern. In the laboratory, scientists have been able to grow almost every cell type. We can grow nerve cells, can grow liver cells, kidney cells, heart cells. You can even see little pieces of beating heart tissue in a test tube. But taking those pieces of tissue, and then taking them back to the patient, is not nearly as simple. So we're, I would say sort of halfway there. We know how to grow these things outside of the body, now how do we make them functional for the patient, and maybe more importantly, how do we integrate this sort of science into the practice of medicine today.

FLATOW: Right. Let me ask Dr. Lysaght about that. How, for example, how expensive would it be for people, who are not laboratory test subjects, like these people were, to create something for them like this?

Dr. LYSAGHT: Well, you know, all of the organ replacement technologies that are out there today, the first generation that you spoke about in the introduction, tend to be fairly expensive. You know, to get a new pacemaker, an artificial hip, you're looking at 10, 20, $30,000 for the total cost of the device, the implantation, the rehabilitation, and so forth, and then a maintenance cost every year. So, I think that the price, once these reach a large volume, will probably be in that same range. An organ transplant, for example, you know, a kidney transplant, for the first year, the kidney's free, but everything that goes with it probably ends up costing 80 to $100,000. Liver transplant, 300 to $400,000. So, these are all very big ticket items. There's no question about it. But they allow people to live longer lives and higher quality lives, significantly higher quality lives. And society just has got to decide, is that how they want to spend their resources.

FLATOW: Could we expect to see this, I'll ask you, Dr. Badylak, also Dr. Lysaght, can we expect to see the bladder treatment find its way to the mainstream public now?

Dr. BADYLAK: Well, you know, it's a very, very special and small subset of patients that actually are eligible for the bladder. So far, at least, in its current form, the cells have got to be harvested from children, not from adults, because children, child cells, have a greater ability to proliferate. And the greatest need for bladder replacement is in bladder cancer, which is an adult disease, and where the use of the patient's own cells might be problematic. So, I think if it becomes a therapy, it will be a niche therapy initially, 500 to 1,000 patients maybe in the United States. And then, as it develops and emerges, it may become a much, much larger scale therapy.

FLATOW: Mm-hmm. Would it be possible to use therapeutic cloning, stem cells, here to grow the same kind of cells, bladder cells, on a matrix for adults where, as you say, they are not proliferating at that age?

Dr. LYSAGHT: If you could get them, yeah.

FLATOW: Yeah.

Dr. LYSAGHT: It'd be ideal. But, by the time you get to be an adult, you don't really have Pluripotent stem cells left.

Dr. BADYLAK: But I think there are several alternatives for doing exactly what you've indicated there. And there are, of course, many different types of stem cells, and let me just give you a couple of examples. There's been talk, for example, of patients, of parents collecting the blood from the umbilical cord of their newborn babies, freezing these cells back, which are rich in stem cells, just in case some day this particular patient develops a need for such a therapy. In that case, of course, you've got a rich cell source of the patient's own cells that are very vigorous and vital and of potential use. Now that sort of strategy is talked about, and there are some blood, you know, cord blood banks now being started, but of course, it's going to be decades before that becomes a reality. There are stem cells being identified in every tissue, and every patient has them, but Dr. Lysaght's correct in that as you get older, the numbers of them get less. But I think this is the promise of stem cell therapy, that if we can understand how to make a stem cell turn into a urinary bladder, or a liver, or a heart, then we certainly have an almost unlimited source of cells. The thing we need to remember is that they need -- when cells are used in this type of a treatment, they really need to be the patient's own cells. Otherwise, the patient needs to be subjected to immunosuppression or you know to...

FLATOW: Right.

Dr. BADYLAK: ...suppress the immune system, like patients who get kidney transplants, and that decreases from the quality of life. So, I think the goal of regenerative medicine and tissue engineering is to get around that.

FLATOW: Dr. Badylak, will there be a time when we're able to actually regenerate limbs, like, you know, some of the animals do?

Dr. BADYLAK: Well, you know, that is, again, another level of complexity, but we believe that that is going to possible once we understand more about the signals that turn on and turn off the normal development. We have, let me give you an example of a strategy that just, you know, sort of tells you that it can happen. You know, in a developing fetus, you can cut off a portion of a limb, and if the fetus is young enough, it will grow back the entire limb, just like a starfish or a salamander. And then, as the, of course, in a newborn, up to a couple years age, you can cut off the end of the finger and it will re-grow to be a totally normal finger, no scars, no nothing. We turn into a teenager, we can't do that anymore, we start to get more scarring, and as we get an adult, we can't, we can barely do it at all, and we develop scars all the time. So, what is it, it's the same patient just healing in a different way as it goes through age, it goes through life, from a developing fetus all the way up? Well, so one strategy, you know, that would be either...

FLATOW: Dr. Badylak? Doctor, we have to go to a break, and I don't want to cut you off in the middle of your strategy, so...

Dr. BADYLAK: Yeah.

FLATOW: Hang on to that thought.

Dr. BADYLAK: I will.

FLATOW: And we'll talk about how your strategy for regenerating limbs, which is going to be quite interesting, when we come back after this break. Stay with us. We'll be right back.

(Soundbite of music)

FLATOW: You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow. We're talking this hour about tissue engineering and bionics, with my guests, Stephen Badylak, research professor in the Department of Surgery, University of Pittsburgh. Michael Lysaght is Professor of Medical Science and Engineering and Director of the Center for Biomedical Engineering at Brown University in Providence. And when I rudely interrupted Dr. Badylak, he was telling us about his strategy for regeneration of limbs. Would you continue please?

Dr. BADYLAK: Well, it wasn't so rude, but what we're talking about was the way that a fetus heals differently than a child, versus an adult. And, you know, one strategy that I think has a lot of potential is understanding how we turn on and off those signals that make us heal more like a fetus. And really, all we would need to do is turn it on temporarily. You know, say you get, you know, you amputate a finger. Well, if we understood the signal that said how did that finger develop when we were a fetus, and we were able to turn those genes on, and turn the other ones off that were keeping it from happening, just like we did when we were little, we could, theoretically, re-grow that body part, and let nature take its course. And that way, we're not supplying cells, necessarily, we don't need scaffolds even, maybe, we just need to understand the mechanisms for tuning on and off these signals. So, there are lots of approaches to regenerative medicine, and I think the value of Dr. Atala's work is to show that, you know, we're working at this, this is possible to do. You know, it's very early, and Dr. Atala would be the first to admit that, and acknowledge that there's a lot of work to do, but it's, I think, extremely exciting because it offers hope to people for things that we just couldn't do before.

FLATOW: Are we any close, are we able to find the genes, at least in animals, that signal the turning on and turning off? I just, I guess I'm trying to get a sense about how close we are to discovering those mechanisms.

Dr. LYSAGHT: Yeah, I expect we are a fairly long way away from the point that you're going to be able to regenerate entire limbs. They have identified some of the genes in animals. But even today, there are, as you mentioned earlier, very advanced electromechanical prosthetics, and it's possible to transplant hands, for example, from cadaveric donors into living recipients. So, these things are evolutionary. And I think it's important to emphasize how much of the bionic vision is already in place. I mean, there are probably 40 million people in the world living with or because of artificial organs, first generation artificial organs, that have been implanted into them, people with artificial hips and knees, with drug eluding stents, with pacemakers, people with living on kidney dialysis, and so forth. And the capacity to replace a deteriorated organ with a manmade substitute is a reality for many organs today, and...

FLATOW: You made it easy for me to bring in my next guest.

Dr. LYSAGHT: Okay.

FLATOW: Dr. Lysaght, my next guest has been working on a device to help amputees regain the function of a missing limb. He's developing a computer-controlled hand, still in the prototype stage, called dextra. And it's amazing how much of a range of motion this hand has. He joins me now to talk about it. William Craelius is professor of biomedical engineering at Rutgers University in Piscataway, New Jersey. Welcome to SCIENCE FRIDAY.

Dr. WILLIAM CRAELIUS (Professor of Biomedical Engineering, Rutgers University): Thank you, Ira.

FLATOW: Tell us about this dextra hand. Is it true that this hand can actually play the piano?

Dr. CRAELIUS: Well, when attached to an amputee, yes, it has played a slow piano piece, and it can do that, yes.

FLATOW: And tell us how, what makes your hand unique from other hands, and hands have been around for decades?

Dr. CRAELIUS: Well, it's really nothing that special. The hand itself is really rather crude. The main, I would say, the main breakthrough we have is the ability to extract more information from the amputee himself, and more than is currently available. So, in our method, basically, is a non-invasive method to image the residual limb with more resolution, I think, than has been done before. People are probably familiar with myoelectric arms that are used by many amputees, and used very well, and these are used by people with trans-radial amputations, as well as trans-humoral amputations, that is above the elbow. But these, for really many decades have been in use, but really only allowed opening and closing of a hook-like appendage, even though it looks, it looks cosmetically very much like a hand now, but they have not been able to control multiple fingers.

So, our breakthrough, with a lot of intelligent and smart students from Rutgers, and some collaborators, but with some very dedicated amputees, who not only had a desire to use, to play, you know, like the piano, or a saxophone, but we found had the ability to express their volition with their limb. And it's probably what I call best, the best analogy is the phantom limb phenomenon, and that is, they think about moving their various digits, and they can really visualize this. In fact, when they close their eyes, I think they imagine that they still have the hand, and that's important. So, all we really did...

FLATOW: So you, so you hook up, you hook the hand up to the muscles? Do you have electrodes that go to the muscles in the body?

Dr. CRAELIUS: Well, it's really not electrodes. What it really is to put a sensor sleeve on the limb that takes sort of a mechanical image of the muscles within the socket as the person is trying to make particular movements. So, the individual basically trains the computer to what he wants to move, and the computer kind of learns, well, I associate these various images with these various movements, and then he simply plays it back and the hand operates in accord with his wishes.

FLATOW: So he has a hand, part of an arm attached and the hand senses the muscle movements in his arm, that's the part that still is present, and you train it to know which of those muscles movements, what it means to do with your fingers, for example?

Dr. CRAELIUS: Yes, that's exactly it.

FLATOW: How much training does it take?

Dr. CRAELIUS: Just really a few minutes. With the very first time, the very first time we really assembled it on our first trial amputee, it took about a few minutes, literally, and he played Mary Had a Little Lamb almost perfectly. So it's, to get three fingers to work, coordinated fashion, does not take very long at all.

FLATOW: Do you think that you can create or restore movement in any limb of the body this way?

Dr. CRAELIUS: Well, see, the arm, I think, is the most difficult. I think legs, really are, they're a rhythmic activity, and the kind of technology we have now is really very, very good and doesn't require, you know, all the kind of work that the upper limb, which, the upper limb can do anything. You can do a task in an infinite number of ways, and so you really have to be well connected. The person has to be very well connected to his robotic arm, whereas the leg pretty much has a very set repertoire of things to do. So, I think that we're really talking about the difficulty is the upper limb.

FLATOW: What is the main stumbling block that you have, are overcoming, and that everyone must overcome in bionics?

Dr. CRAELIUS: Money. Funding. Because I would say that it's quite expensive to develop these things. And even though it's a severe problem for many people in this country and throughout the world, the funding, there is not that large of a market. It's not like selling televisions. And so that's, I would say, the number one problem. Now, if you mean technologically, really, I think, everyone will recognize that the man-machine interface is the key problem to be solved because we have the robotic technology, we have the computer technology, we have batteries, we have motors. The interface is the main issue.

FLATOW: You mean how much information you can get from the muscle to the arm, or to the other bionic part?

DR. CRAELIUS: Yeah, that's correct. I think that there's different approaches. I mean, as you know, as you probably know, people now are looking at trying to record directly from the brain, from the, right from the brain with electrodes, and have a person do the same sort of thinking, but tap in directly there and then control the limb. And other people are trying the peripheral nerves directly within the arm with surgical techniques. Our technique, which is in use, is non-invasive, and it will have a limit. I mean, I don't think people are going to be able to, you know, get a lot of dexterity like, you know, playing Chopin on the piano, but I think that they'll get a lot more than they presently are given with the myoelectric.

FLATOW: Would they be able to walk?

Dr. CRAELIUS: To walk?

FLATOW: Yeah, so that someone without legs, if you put these artificial limbs on them, would they be able to walk with them?

Dr. CRAELIUS: Oh, I personally, you know, we're not involved in making lower-limb prostheses, but those are really high technology and very, people, there's been a double amputee who nearly won on an Olympic race.

FLATOW: Mm-hmm.

Dr. CRAELIUS: So, I think that the leg prostheses are very well designed and really can get people up and walking and running. No question about that.

Dr. LYSAGHT:: Somebody with an artificial leg today can run the 100 yard dash one second less than the Olympic record.

IRA FLATOW: Mm-hmm. 1-800-989-8255 is our number. I want to bring in another researcher who says they've designed a bionic eye that could cure some forms of blindness, an eye that holds the potential to give completely blind people 20/80 vision. That means they'd be able to read books, to use a computer, and recognize faces, the researchers say. And let me give you an idea how it works. There's a light sensitive chip about half the size of a grain of rice that's implanted behind the retina of your eye, you wear a pair of goggles that have a tiny video camera attached, and the camera sends what it sees to a pocket sized computer processor, the computer sends the image back to the screen on the goggles, the screen projects the light onto the chip implanted in your retina, the chip stimulates neurons, cells that send signals to the brain creating sight. And so far, the bionic eye has only been tested in rats, and it can only sense images in the infra-red, sort of like black and white night vision. But it holds potential and here to talk about it is Dr. Daniel Palanker, head of the research team creating the bionic eye. He's a professor in the department of ophthalmology at Stanford. He joins us from Palo Alto, welcome to SCIENCE FRIDAY.

Dr. DANIEL PALANKER (assistant professor, Department of Ophthalmology, School of Medicine): Good morning.

FLATOW: Good morning. How, did I describe more or less correctly?

Dr. PALANKER: That's right, yes.

FLATOW: How close are you trying this out in humans? What needs to be done?

Dr. PALANKER: Well, at this point we are trying bits and pieces in rats and rabbits. We are probably couple years away from human trials of that system.

FLATOW: Mm-hmm, and can you give us any idea of what, I mentioned how good the resolution was, how do you know how good the resolution is in the rat study?

Dr. PALANKER: First of all, the design of the system is such that, oh, let's say, physical limitations of interface between the chip and the neurons in the retina is such that amount of information is limited by the size of the pixel, the pixel density, and distance between the electrodes themselves. So, the maximal amount of information that we can deliver responds to visual acuity of 20/80, as you mentioned. However, we start human trials, will be started with lower resolution, at about 2400, which corresponds to basically the definition of legal blindness in U.S. And the second generation will be half of the size of those pixels, so it will be 20/50, and then, the next generation 20/80. So the proximity is one of the central issues that we have to overcome. We found fascinating phenomena that basically helped us to resolve this issue. The implant having three dimensional structure, when implanted in sub-retinal space induces migration of the retina and integration of the neural cells via the implant. So they basically come into intimate proximity of electrodes and that what helps to resolve the issue of proximity, the degree of microns. We observe this phenomenon now in rats, in chronic studies, and acute studies in rabbits, and as I said, that's what basically defines the amount of information it can deliver and ultimate resolution.

FLATOW: Mm-hmm, we're talking about bionics this hour on TALK OF THE NATION'S SCIENCE FRIDAY from NPR News. Dr. Palanker, are you saying that the neurons migrate to the implant and make a good tight contact with it?

Dr. PALANKER: That's right.

FLATOW: Are they trying to heal it? Are they trying to, how do, why do they do that?

Dr. PALANKER: It's probably a wound response. We don't know yet the exact mechanism that drives this. It was actually discovered only two years ago and we now study the driving forces behind this migration. It occurs only in subretinal sight, it doesn't happen in epiretinal, that is why epiretinal approach has limited promise in terms of special resolution. The amount of information it can deliver and visual acuity that they can achieve.

FLATOW: Do you think that you might have found a way to help the retina heal itself?

Dr. PALANKER: No, it's not the way for retina to heal itself, because in retinal degeneration the photo receptors die, and we are not going to restore them. We are going to interface with the surviving neurons. There are two other layers of cells in the retina, bi-polar cells and ganglion cells that process information and send it to brain. So, we are interfacing with those neurons.

FLATOW: What would be the ultimate implant? What, you know, down the road what would be the ultimate implant, what would it be able to do?

Dr. PALANKER: It will, the system as you described already has some hardware for image acquisition and processing outside the eye and information is delivered into the eye what it will do eventually, it will deliver information is such a way that patient will perceive images, and one of the big questions actually here is unknown so far is what kind of image processing we'll need to do in between the camera and the implant to make it perceived as an image. It took about ten years of research for cochlear implant to come up with reasonable signal processing to make the signal understandable as sound and speech recognition, so that still is ahead of us in retinal prosthesis.

FLATOW: Mm-hmm. 1-800-989-8255 is our number. We're gonna go to the phones in a little bit, see if, get some questions from our listeners. How far do you think until human usage of this? You say you're going to start human trials in a few years, within a couple years?

Dr. PALANKER: We plan to start in two years. Actually, the major limiting factor for us is funding and...

FLATOW: This is the second time I've heard on the program that funding is limited. You would think that with all the people who need, could use these things, that funding would be overflowing.

Dr. PALANKER: I would be happy to see it happening, it doesn't happen, however. This year NIH used to budget somewhat and it's, the payline now is about 13 percent, so it's very difficult to get funding even for projects of, as interesting as this one.

FLATOW: NIH reduced its funding?

Dr. PALANKER: That's right.

FLATOW: All right. We're, we'll come back and talk more about that. Stay with us, we'll take a quick break and talk more with Dr. Craelius, Palanker, Lysaght, and Badylak. And your questions, we'll get them in there, stay with us, we'll be right back after this short break. I'm Ira Flatow; this is TALK OF THE NATION SCIENCE FRIDAY from NPR News.

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FLATOW: You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow. We're talking this hour about bioengineering with my guests Stephen Badylak, Michael Leiset, William Craelius, and Daniel Palanker. Our number, 1-800-989-8255. Let's see if we can get a phone call or two in here. Chris in Napoleon, Ohio. Hi, Chris.

CHRIS (Caller): Hi, how you doing today?

FLATOW: Hi.

CHRIS: Thank you for taking my call. This is a really great show for me because I have a four-year-old son who's diabetic, and, you know, all the talk of being able to grow new organs, you know, it would be really nice if it could happen now, but I realize that it's not yet. I was curious as to, you know, I realize they had to start with a bladder for the simplicity of the organ, but what kind of time are your guests thinking that more complicated organs may be able to be tested on humans, such as the pancreas, or other organ, liver, etc. And is there any problem with organs like that, so far, are there going to be problems with, you know, the body rejecting stuff like that or...

Dr. STEPHEN BADYLAK (University of Pittsburgh): Each organ, this is Steve Badylak, each organ has its own challenges and, of course, there are so many diabetics that would just do anything to have their insulin-creating cells replaced, and it is, of course, there's a terrific amount of work being conducted in this area, has been for decades, and disappointingly there's really been very little in terms of translation of the progress that's been made to patients yet. However, the Juvenile Diabetes Research Foundation has recently, in the last couple of years, focused their efforts on treating the cause as opposed to the symptoms and signs and outcomes of diabetes, so there's a large, large effort going on right now to do exactly what you want, which is to figure out how to either make your own cells turn into insulin-secreting cells that would replace those that are missing, or some of the therapies similar to what Dr. Atala did with the urinary bladder.

In terms of your question regarding the timeline, every organ's different. People would like to have it yesterday, of course, but it's going to be a bit at a time. There are things out there now that you may not be aware of. Cartilage cells are being taken from patients, grown up, and being taken back to the patients now. These are being done at costs of 25 to $30,000.00. There are pieces of skin grown in a bottle that are being used to treat patients right now. You know, and Tony Atala has shown that you can take bladder, so a bit at a time, and listening to the other scientists on this show, it just, I think, gives you some idea of how complex the human body is. How, in spite of all of the things that we try and do, you know, we really cannot duplicate what Mother Nature has done, and so it's, you know, we've got to come at this from all directions.

FLATOW: Let me focus on the pancreas for a second because we talk about diabetes and, all the time. Is this a particularly tough organ to grow on a matrix, a structure like you did for, what was done for the bladder?

Dr. BADYLAK: Yes, it is, because for whatever reason, these cells can be harvested from donors, but cannot be expanded to any extent in culture right now. There's an effort by the JDRF right now to see whether we can get 100 fold expansion of these cells, so that we can take one pancreas and treat multiple patients, but as of yet, that's not possible. In fact, we're not even entirely sure what the stem cell is that ends up being an eyelet cell, one of these insulin-secreting cells.

Dr. LYSAGHT: And, this is Michael Lysaght, the pancreas is particularly difficult because if you were to return an expanded line of the patient's own cells back to a diabetic individual, those cells would probably be subject to the same auto-immune attack that destroyed the original cells, so that, I mean, the pancreas is one organ that can't be transplanted between identical twins, for example, because the patient's own cells have been rejected by its own body, causing the diabetes in the first place. So, at least for juvenile diabetes, the challenge is perhaps, I mean, I think the bioartificial pancreas probably represents the greatest engineering challenge of the early 21st century. It's a very, very complicated organ.

FLATOW: I'd like to get back to the money question because if I'm, if I hear you all correctly, the stumbling blocks are not really engineering stumbling blocks here, they're funding stumbling blocks. Would that be correct?

Dr. BADYLAK: Funding is always an issue, and unfortunately for the first time in 35 years, the NIH has decreased its funding levels. And this is not simply because people aren't interested, or that they want to decrease these funds, of course, there are other priorities, you know, that the government, I guess, has decided go before this sort of work. NIH is the most generous massive funding institution in the world when it comes to medical research, but this sort of work is expensive. And it takes a lot of effort. And one laboratory in California, or Pittsburgh, or New York, isn't going to do it. This is the sort of thing where you have to have many, many people working on it, all working together, and one person discovering one little thing like, you know, what Dr. Atala has done, building on something that might be done in Dr. Lysaght's lab or someone else's lab, and then eventually we get there. But it's, money is always a limiting factor. All of us could use more money.

FLATOW: Mm-hmm. Dr. Craelius or Dr. Palanker, what about private funding? If you're creating bionic parts, would there not be a market for them?

Dr. CRAELIUS: Well, I think the market for upper limb prostheses is generally considered to be quite low. Even though...

FLATOW: But you go, if you go to a VA Hospital these days, you'll see plenty of them.

Dr. CRAELIUS: Right. And you can get people walking quite cheaply with, you know, century-old technology. And you can get people at least having a hook with century-old technology. And so, the incentive to improve that is simply not there.

Dr. PALANKER: For vision, for retinal prosthesis, the market is considered to be quite large. And there is some interest in private sectors, actually two companies in U.S., in this market, and two in Germany, and I think there is one in Japan, at least. However, there is a lot of basic research still remaining to be done in university environment, and funding from private institution into universities is quite problematic. A lot of conflict of interest issues, and it's not easy to implement. However, we are looking into it right now because NIH funding is so tight.

Dr. LYSAGHT: Ira, you may or may not know, too, that a significant amount of funding for this type of work, particularly the prostheses, comes from the Defense Department, not the NIH. And they have parallel efforts in both better prostheses that need to be developed, as well as limb and digit regeneration. We have a human clinical trial beginning later this year on digit reconstruction down at Fort Sam Houston that is funded entirely by the Defense Department. This is in, people don't think of the Defense Department as a funding source, but in fact a lot of monies actually do come out of there. And it's recognized as a priority.

Dr. CRAELIUS: Yeah, and the Veteran's Administration has a very large program directed specifically at improved prosthetic limbs for traumatic limb loss.

FLATOW: Mmm. If you can get tissue cells to grow on a structure, why can't you lay down a path, for example, for nerve cells in a spinal cord and have nerve cells regenerate and grow along that kind of pathway?

Dr. LYSAGHT: Well, this is being exactly that, pathways laid out, and nerve cells can be stimulated to grow along those pathways. And they can be done in culture. The problem is the same that was identified earlier on the artificial hand. It's the interface between what you make outside of the body and then when you try to take it to the body. I think that this is an important question that needs to be addressed, whether or not the ideal path is to try to figure out how to do it outside the body and translate it in, or whether, how to use the body as a bioreactor and stimulate the signals that let the body build these things, so that it integrates it in, at the, while it's being made, so to speak.

FLATOW: Hm-hmm. 1-800-989-8255. Rick, in Lebanon, Oregon. Hi. Welcome to SCIENCE FRIDAY.

RICK (Caller): Thank you Ira. I appreciate you taking my call. I'm a family physician. I've practiced here for over 25 years. The last 20 years of my life I've been trying to figure out how to get basic healthcare for all. Like, immunizations, and prenatal care, and this discussion is wonderful, it's really about hope. But when I come to it I feel like a curmudgeon because I come saying, How are we going to pay for it? Fifty million people in this country without access to basic healthcare. Industries feeling that they're non-competitive worldwide because of their healthcare costs. Yet, we continue to develop technologies, which we should, that cost more and more for a smaller number of people. And who decides who's going to pay for it? The VA's paying with tax dollars. We have all sorts of competing needs around healthcare, so we haven't really decided who should pay, who should decide, who should get. And we also sort of have a everyone should live forever and not have health problems. So, I'm really concerned about how we balance the expanding technology with the costs and the fact that we currently don't provide basic healthcare to 15 to 20 percent of our population.

FLATOW: Dr. Lysaght, do you have any comments on that?

Dr. LYSAGHT: Well, yeah, I mean, I think it's a very good question. How a society chooses to allocate its resources is really what it comes down to. There, but I don't see a direct link between developing technology that will let people live longer or live better lives, and a higher quality life, on one hand, and dealing with the problem of the uninsured on the other hand. That's more of a problem of distribution of resources rather than availability. I mean, I just think that we should spend, and be willing to spend, money on providing better lives for our citizenry, rather than on, you know, more, rather than on, say, faster digital pornography or bigger gas guzzling cars. It's a higher and better use of those resources, and it's just a matter of policy and politics until the money is channeled in those directions.

FLATOW: We're talking about bionics this hour on TALK OF THE NATION: SCIENCE FRIDAY from NPR News. 1-800-989-8255. Gentlemen, in the few minutes we have left, if you could make a breakthrough on some area of your own, what area would you like that breakthrough to come from? And let me begin with Dr. Badylak first.

Dr. BADYLAK: Well, I think we're very close in the area of stem cell research, and I think there's always this concern that when the word stem cell is used people think of embryonic, human embryonic stem cells, at the ethical issues there. I think we need to do a much better job of educating the public in terms of the many, many different types of stem cells that are there, and the importance of understanding how to get these cells to do what we want them to do, and then translating that into clinical practice. We cannot afford to be out of this game. It is the, I think, the area that has absolutely the most potential to change the practice of medicine and the quality of life within our lifetime. I'm not talking about something ten, twenty years, I'm talking within the next five to ten years.

FLATOW: Mm-hmm. Dr. Craelius?

Dr. CRAELIUS: Well, my immediate aim, I think it's, again, I'd like it within my lifetime, and that would be to, basically to take and be able to give people who need it today, a lot more functionality in their hands. People who are trans-radial amputees, even trans-humoral amputees, to be able to take the signals that their giving right in their arm and translate it into movements that they can enjoy and use.

FLATOW: Mm-hmm. And what would you need, what kind of breakthrough would you need there?

Dr. KRALIOUS: It's really, I guess it's not so much a breakthrough as a follow-through, is the way I look at it. Because right now in my laboratory, with many students, we have a lot of different techniques that can be implemented out in the market, out in the commercial usage market, to give people more functionality. I think, coupling the various technologies, for instance, there's hands that are available, developed in England, developed in Germany, that could be coupled with our new interface technology, that would get people today who only have a hook out there and be able to do things like, play the saxophone a little bit with their residual limb, as well as type, and be able to do a lot more versatility than they can presently do.

FLATOW: Mm-hmm. Dr. Palanker?

Dr. PALANKER: I think we'll see, in a few years, very significant progress in restoring sight of the blind, people having retinal degeneration. And one of the most important unknowns here is that we'll be able to address as soon as we have high-resolution implants in the human eyes, is the question of image processing. That we'll be able to address, and this I think is one of the biggest questions remaining. What image processing we will have to look through from outside the eye, so patients will be able to perceive this information as coherent images.

FLATOW: Mm-hmm. Dr. Lysaght, last word.

Dr. LYSAGHT: Thank you. I think that it's really, there are three levels that these activities are going on. The first is to continue to evolve the first generation of artificial organs, the hips, the knees, the pacemakers. And a good example of that is stents, where stents that are available today function an awful lot better than those that were available ten years ago. The second area is to add a little biologic functionality to man-made organs, and that's what tissue engineering is going to do, to allow organs to grow and remodel and be accepted into the body. And that's where Dr. Atala's great contribution, which the bladder is really validating...

FLATOW: Quickly, I've got a, just a few seconds left.

Dr. LYSAGHT: All right. And then finally, as Steve said, is stem cells. That really is the ultimate achievement that I think we're looking for.

FLATOW: All right. I'd like to thank all of you for taking time to be with us. Dr. Stephen Badylak, Dr. Michael Lysaght, Dr. William Craelius, and Dr. Daniel Palanker. Thank you for taking time to be with us today, and good luck to all of you.

ALL: Thank you.

FLATOW: We'll be checking in.

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