5 Things podcast: The organ transplant list is huge. Can pig organs help?

On today's special episode of the 5 Things podcast: U.S. surgeons have completed over a million transplant operations since they started doing them nearly 70 years ago. Still, each year about 100,000 Americans sit on the waiting list. Many more never even qualify for the list. The problem is one of basic supply and demand. Dr. Robert Montgomery, director of the Transplant Institute at NYU Langone Health is hoping to change that equation to give more people a chance at a longer, healthier life. He joins the 5 Things podcast to discuss his research involving a pig's kidney transplanted into a human patient.

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Hit play on the player above to hear the podcast and follow along with the transcript below. This transcript was automatically generated, and then edited for clarity in its current form. There may be some differences between the audio and the text.

Karen Weintraub:

Hello and welcome to Five Things. I'm USA Today health reporter Karen Weintraub. The first successful transplant surgery was done in 1954 with a kidney transplanted from one identical twin into another. Since then, US surgeons have completed over a million transplant operations. Still about 100,000 Americans sit on a waiting list for an organ transplant, and many more never qualify for a list at all. The problem is one of basic supply and demand. Dr. Robert Montgomery, director of the Transplant Institute at NYU Langone Health is hoping to change that equation to give more people a chance at a longer, healthier life. Dr. Montgomery, thank you for joining me.

Dr. Robert Montgomery:

And thank you, Karen. It's nice to be here.

Karen Weintraub:

Maybe you could start by telling us a little bit about 57 year old Maurice Miller, whom everyone calls Mo.

Dr. Robert Montgomery:

Mo's a gentleman who developed a really terrible tumor, brain tumor that has a very high mortality rate, and he presented actually at a hospital, didn't know that he had a brain tumor after a seizure, and then he passed out and was found down and they tried to biopsy the tumor and it bled and he bled inside his head and then became brain-dead. And that's when we found out about him because he had indicated that he wanted to donate his organs when he died, but because he had this particular type of very aggressive brain tumor, he wasn't a candidate for organ donation. So the folks who from our organ procurement organization who were working with his family told them about this other option where he could donate his entire body for the purposes of research study.

Karen Weintraub:

Mo's been in this ICU room for about two months that had special meaning for you and not just because it had a beautiful view of the East River. Can you explain a little bit about what that room means to you, meant to you?

Dr. Robert Montgomery:

The special significance that the room has is that's where I spent over a month waiting for heart transplant five years ago, almost exactly five years, and then recovering from that transplant. And that's where he spent two months with a pig kidney inside his body doing everything that was required of it to filter out the toxins in his blood and do all the other things that a kidney does.

Karen Weintraub:

Why did Mo or his sister agree to let him participate in this research?

Dr. Robert Montgomery:

Mo's sister Mary, who was very close to him, really felt that this was something that he would want. He was a very kind-hearted person, very giving, cared about other people, and so she thought this was in perfect alignment with the person that he was.

Karen Weintraub:

And talk to us a little bit about the surgery, the process itself. What did you do?

Dr. Robert Montgomery:

We set up the transplant just like we would any other transplant between two humans. So we sent a team down to Virginia where the pig farm is on a jet and they procured the pig's kidney and flew back. And at the same time, I started the recipient operation on Mo and we did the kidney transplant just like we would a regular transplant except for one thing, we removed his own kidneys, so his native kidneys so that all the urine and all the work that a kidney has to do would need to be done by the gene edited pig kidney. So we would be able to separate that out and really test the kidney and know exactly what it was doing and how well it was performing.

Karen Weintraub:

Can you tell us a little bit about the pig? Gave its life for this procedure.

Dr. Robert Montgomery:

The pig is raised in a very clean environment and is monitored. We do surveillance for about 35 different pathogens, viruses, bacteria, parasites. And so we know exactly what the state of that pig's health is and exactly what it's been exposed to. It has a lot of activities and toys and things like that. And then at the time that we remove the kidney, it's given a general anesthetic so it doesn't have any pain. And then given a lethal injection after the kidneys are removed.

Karen Weintraub:

You talked about the gene editing. What genes are edited in this pig?

Dr. Robert Montgomery:

So for this particular pig, it's actually a pig line. So there's a herd of pigs, they're called GalSafe pigs, and they've had one gene knockout. And that gene is responsible for creating a carbohydrate that coats all of the cells of the pig. And that carbohydrate, the enzyme that that has actually been lost during evolution from pig to human. So humans don't express that carbohydrate, but that carbohydrate is shared by bacteria. So we make a very strong immune response to that carbohydrate in order to keep bacteria inside our gut.

Karen Weintraub:

So the purpose of this research was to see if the kidney could function, the pig kidney could function in the person without triggering an immune response over this time period.

Dr. Robert Montgomery:

It wasn't rejected and had good function, but that's about all we could really answer from a three-day study. For this longer study, which in the end, we reapproached the family and our institutional review board, we got permission to extend it to two months, and we were able to answer some important questions. Number one, what about what's called the adaptive immune response? So the adaptive immune response is we have an apparatus in our immune system that allows us to engage a novel foreign material, whether it's a virus or foreign tissue, and develop a well choreographed, very strong immune response. But it takes time. It takes somewhere between 10 to 14 days to really develop that response so that you can essentially slay the invader and get rid of that foreign material that's in your body. So the reason why we really wanted to go up to at least a month is so that we could see that adaptive immune response fully developed. And then the second thing we were really looking at is does the pig kidney take up all of the regular functions of the kidney, aside from just making urine and clearing toxins?

Karen Weintraub:

And did it work?

Dr. Robert Montgomery:

Well, it functioned great. So it functioned even better than a human kidney because actually pig kidneys have twice as much function as a human kidney. The kidney was just as good, maybe even a little better at the end of the study, at the end of the two months. So the function was great. He did have a mild rejection, which was actually good because we could not only study it and begin to understand what rejection looks like between a human and a pig organ, but we could also treat it and use our therapeutics to try to reverse it. And so he had a mild rejection and it was fully reversible, and that was really important information as well.

Karen Weintraub:

And what do next steps look like? What do you do next in this process?

Dr. Robert Montgomery:

Those initial studies that we did gave us a lot of information. But this study, I think really looking at this kidney after 61 days and seeing how well it was functioning, there wasn't any protein in the urine and there wasn't any ongoing rejection. It really looked very pristine and was doing essentially all the things that a human kidney would do. I think this is a big jump forward, and I think the FDA, once they've had an opportunity to review all the data and we're still analyzing it, I think is going to really take the work in humans and the human decedent model very seriously. And it should accelerate us towards clinical trials. So I think you're going to start to see some living humans transplanted very soon, and a lot of it is going to be the result of this last study that we've just done.

Karen Weintraub:

And how do you hope this research ultimately changes the world of transplants?

Dr. Robert Montgomery:

The single most significant unmet need in transplantation is organ supply. And we can't even begin to estimate how big that problem is because so many people die even before they're counted on a transplant list. Only the people that we think have the best chance of survival ever even make it to a transplant list. So there's a tremendous amount of lives that are lost. I mean, myself, I had seven cardiac arrests where I had to be resuscitated, some of those which required prolonged CPR that I was just very lucky to have survived before I was deemed to be sick enough to get listed for a heart transplant. And so just to give you a sense, every year there are a million people in the United States that are newly diagnosed with heart failure. The mortality rate for heart failure over five years is 50%. Last year we only did about 3,500, 3,600 heart transplants.

So a million people with heart failure and just under 4,000 transplants. Think about that. Not even really dealing with the tip of the iceberg when it comes to organ failure and transplantation. If we had an unlimited sustainable supply of organs that didn't require to have someone die in order for someone else to live, but we could basically, whenever someone needed a transplant at the time they needed it, rather than having them wait for years and die on the transplant waiting list, we could transplant them with a pig organ. It would change everything.

Karen Weintraub:

Anything else you want people to know about this kind of research and why you're so passionate about it?

Dr. Robert Montgomery:

In the run-up to getting listed for a transplant and recovering from multiple cardiac arrests and then sitting in the ICU waiting for an organ, not knowing whether one was going to come, I had a lot of time to think about this. And I'm passionate because I've lived it. I've walked in those shoes. I know what our patients go through, and I just foresee a life that's going to be different where people don't have to die waiting for an organ.

Karen Weintraub:

Thank you so much for joining us. Really appreciate it.

Dr. Robert Montgomery:

It's been my pleasure. Thank you, Karen.

Karen Weintraub:

Thanks for watching.