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EP220: Pigs May Not Fly, But...

Host:

Doctor Warrick

Mar 13, 2022

Played 1273 times

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Risks, Heart Health

Welcome to my podcast. I am Doctor Warrick Bishop, and I want to help you to live as well as possible for as long as possible. I’m a practising cardiologist, best-selling author, keynote speaker, and the creator of The Healthy Heart Network. I have over 20 years as a specialist cardiologist and a private practice of over 10,000 patients.

Episode Summary

Dr. Warwick Bishop is a practicing cardiologist and author dedicated to improving patient outcomes through heart health education. In this episode, he discusses the groundbreaking January 2022 pig-to-human heart transplant performed at Maryland Hospital, where the patient remained healthy one month post-surgery. The episode explores the science behind xenotransplantation, the critical challenge of tissue rejection, and why this development represents a potential solution to the severe shortage of human donor organs.

Key Takeaways:

The first successful pig heart transplant into a human patient in January 2022 was a remarkable scientific achievement, with the patient still doing well at one month post-transplantation.
Tissue matching between donor and recipient is critical because the body recognizes foreign cells through complex receptors (similar to blood type markers), and mismatched tissue triggers dangerous immune responses.
Cross-species organ transplantation is far more complex than human-to-human transplants because it requires overcoming genetic differences between species.
Scientists have successfully developed transgenic pig lines with reduced cell markers that prevent adverse human immune reactions, making them suitable for transplantation.
Pigs are ideal donor animals because their heart size and structure are similar to human hearts, addressing a critical medical need.
In the US alone, 15-20 people die daily from lack of available donor hearts, making xenotransplantation a potentially life-saving solution.
The two major post-transplant risks are organ rejection (complicated by immunosuppressant medications that lower immunity) and infection.
Humans have already used animal-derived materials in cardiac care, including pig valves and bovine pericardium valves, establishing precedent for animal-to-human medical applications.
Pig heart xenotransplantation may serve as a bridge solution while longer-term alternatives like gene therapy and genetic engineering are developed.

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Transcript English

**Episode Title: "EP220: Pigs May Not Fly, But..."** **Dr. Warwick:** Welcome to Dr. Warwick's podcast channel. Warwick is a practicing cardiologist and author with a passion for improving care by helping patients understand their heart health through education. Warwick believes educated patients get the best health care. Discover and understand the latest approaches and technology in heart care and how this might apply to you or someone you love. Hi, my name is Dr. Warwick Bishop and welcome to my podcast and videocast station. Today, I'd like to talk about an amazing bit of almost science fiction that has reached us. In early January of 2022, a group of doctors at Maryland Hospital undertook the first transplant of a pig's heart into a human. This is absolutely remarkable. And even more remarkable is that one month post-transplantation, the patient was still doing well. Well, what an extraordinary thought—having a pig that could be sacrificed to provide an organ for a human being. For 15 to 20 odd years, I remember it being discussed over a number of different conferences. Of course, the difficulty is trying to recognize the way the human body will respond to foreign tissue. We know that one human donating an organ to another human can be fraught with problems. There has to be close tissue matching. When we talk about tissue matching, we're talking about a complex number of receptors on cells that give the body an indication as to whether it's dealing with itself or something else. The easiest way for you to understand that is to think about your blood group—A, B, O. All these are receptors or markers for the body, allowing it to know whether it's dealing with its own blood in this situation or someone else's blood. That's why cross-matching is so important before a blood transfusion. If it's wrong, then the receiver of the blood that's not matched properly will incite an immune response and destroy those cells—a disastrous consequence. Similarly, with organs, when we look to transplant organs, whatever organ that may be, there has to be a tissue match. So, imagine how complex that must be when we go beyond human to human and go human to another species altogether. Humans and pigs share a surprising amount of DNA material, and the evolution of these transgenic pigs—these pigs that have genetics that really dovetail or meld with human genetics—has been a process of many years. The remarkable thing about this particular situation is that they've now generated pig lines which have reduced cell markers so that a human body doesn't react to them adversely. Well, why would a pig be used? As it turns out, pigs are not too dissimilar in terms of size, and their heart is not too different in terms of structure. Certainly, there's a need for organs, particularly hearts, and that's why this is so compelling. In the US alone, the statistics are that about 15 to 20 people per day are dying because there just aren't enough donor hearts out there to support people. Of course, the alternate at the moment is using some sort of assist device, which is like a pump that hooks up to the heart and can be battery-powered so that it supports the individual. But these are cumbersome and fraught with risk, particularly of infection. So, the thought of being able to put, if you like, a healthy heart into an individual without rejection as required and have an improved supply for the people who need them is just—it’s science fiction, but it’s here. It’s amazing. The biggest troubles, of course, are going to be with rejection because of the difference in tissue types, and because rejection medications lower immunity. The other biggest problem for the individual who receives a heart would be that of infection. Some people will get caught on the ethics of this, and I'm not going to even jump into that because I think it's incredibly complicated. But humans have used animals for time immemorial for their own use, particularly food. Pigs have been used for food for centuries. We already use pigs, actually, for pig valves in hearts. We're able to use pig hearts and we're able to use cow-made valves, so pig valves and valves made out of cow, which we call bovine pericardium, are currently being used. So, to a degree, we've already touched on using animal parts within humans. It is an extraordinary space. I think we will see more of this. The chance to be able to provide individuals with a replacement organ is incredible. We may see this with other organs as well. And certainly, as we watch over time, this may be a strategy that will support care for needy individuals over the next decade, maybe two, while other mechanisms are put in place—perhaps gene sequencing or gene-altering targeted therapies—which may replace this in the longer term. Anyway, a remarkable story: a pig heart transplantation into a human in early January 2022, still working at one month. Watch this space because it's absolutely fascinating. If you have any queries or questions, drop us a note at info at drwarwickbishop.com. Otherwise, I hope you live as well as possible for as long as possible. Take care and bye for now. You've been listening to another podcast from Dr. Warwick. Visit his website at drwarwickbishop.com for the latest news on heart disease. If you love this podcast, feel free to leave us a review.