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Pig heart transplant failed as its heart muscle cells died
- slowhand09 4y agoMy friend was a member of the transplant team for this. Their explanation was this. His physical condition overall was pretty bad by the time this transplant occurred. He was on the edge of multiple organ failure for weeks afterwards. While his heart was pretty strong, his organs in general were compromised, and in poor condition to support each other. I'm not a medical professional. But I have been present and watched multiple people of systemic failures.
- petra 4y agoGiven that pig heart transplants are only a candidate for people that are a really bad shape, how does your friend see this field advance after this current result?
- DocTomoe 4y agoThe idea is that right now, this is only for people in really bad shape, but with advances and experience, this may become a more standard thing for people in less bad shape. You first try the new, experimental drug on people who may die soon anyways, before you hand it out like smarties at the local drugstore.
- throwaway48292 4y agoStill have to get through that stage though with some good results to show for it, even if we suspect healthy bodies would handle it much better (although I wouldn't personally lose faith based on one instance)
- ceejayoz 4y agoSeven weeks with no sign of immune rejection is a good result here, for the very first attempt. It's largely what they would have been hoping for.
- hericium 4y agoDo you maybe know if they just wanted to check if it will work for some time or hoped that failing organs may benefit from new heart?
- idealmedtech 4y agoI'd be very curious to see what the glucose/lactic acid curve looked like during and after the transplant! Usually it's a good leading indicator of broader issues. We've done a few studies in swine (they're the gold standard of blood sugar modelling) and if an animal was not doing well, we'd always see a spike in lactic acid right before death.
- pazimzadeh 4y agoThe number of people working on xenotransplantation in the world is very small. My mom (https://tts.org/74-ixa/889-ixa-in-memoriam-agnes-marie-azimzadeh https://tts.org/74-ixa/889-ixa-in-memoriam-agnes-marie-azimz...) was part of the group who conducted basic research in xeno at the University of Maryland and established the collaboration to start testing Revivicor's genetically modified pigs, before her lab (https://www.massgeneral.org/transplant/cts/research/pierson-laboratory https://www.massgeneral.org/transplant/cts/research/pierson-...) moved to Boston a few years ago. The international xenotransplantation community found out about David Bennett's heart transplant through the news, and some people feel as though competition between groups may have contributed to a lack of sharing of clinically relevant information that could have benefited Mr. Bennett.
- dvh 4y agoIsn't there a risk of introducing new zoonotic diseases?
- labtheory 4y ago[flagged]
- deleted 4y ago[deleted]
- londons_explore 4y agoYes - the risk is substantially higher because blood flow will allow a virus to move from one tissue type to the other very efficiently repeatedly, and immune response is reduced but not eliminated allowing rapid adaption. As a society we need to think about the ethics implications of using this technique to save some lives while dramatically increasing the risk of zoonotic viruses which will impact many others.
- rwmj 4y agoVery much - hence why the pig is "raised in conditions that should limit pathogen exposure" and the multiple virus tests on both the heart and the patient before and after the transplant. And even then they missed one pig virus.
- Metacelsus 4y ago>raised in conditions that should limit pathogen exposure Except the pig still got porcine CMV from somewhere.
- ceejayoz 4y agoMaybe. > the researchers indicate there's some question about whether the tests that picked it up might have been recognizing a closely related human virus
- mlyle 4y ago
- walrus01 4y agoAt this point in order to be a candidate for such a risky/previously untested procedure, doesn't the person need to be in an absolute worst case scenario, where they've been rejected for all forms of human heart or artificial transplant and highly likely to die soon?
- atian 4y agoHuh? He was.
- beowulfey 4y agoSo then, if it does not work in those conditions, what’s the point?
- mlyle 4y agoIt may have extended life even in this first time. And now we have a bunch of data to try and identify what exactly went wrong. We can try a couple a year, steadily improving until we ultimately get lucky and someone's life is significantly extended.
- barry-cotter 4y agoHe was going to die without this. It would have been immoral to give him a human donor heart that could have gone to someone who could have lived ten or more years with it. Every pig heart transplant they’ll get better at it until eventually if you need a heart transplant you’ll just get one. That’s the point.
- ceejayoz 4y agoIt allows you to test the heart in a human patient without worsening their prognosis. Validating that it's possible allows for carefully expanding to the patients not undergoing massive multi-system organ failure at the time.
- russfink 4y agoWhat I take from your question is, were the other health issues the thing that actually killed the heart? Following from that, how can we declare something not successful when the odds are significantly stacked against it from the start?
- imwillofficial 4y ago
- yread 4y agoI just love that there is an H&E slide on article cover of Ars
- jwilk 4y agoWhat's H&E?
- isaacimagine 4y agoHematoxylin and eosin stain. https://en.wikipedia.org/wiki/H%26E_stain https://en.wikipedia.org/wiki/H%26E_stain
- marsven_422 4y ago
- koheripbal 4y agoThe point is that his heart failed, not some other organ, and while it was functional for a time, the surgeons had stated that it would be functional for longer. While you can soften the failure by highlighting the patient's broad systemic issues, this is still a notable failure that will likely put a damper on future similar pig transplants.
- feet 4y agoThe human body is a system, I'm not a physiologist so I don't fully understand everything. That being said, if organs which normally supply some sort of supportive function to the heart no longer work, it's definitely possible for the heart to fail first. The heart is a mechanical pump remember, easy for it to fail
- rkangel 4y ago> that will likely put a damper on future similar pig transplants I should hope not. Not everything works first time. Hopefully it gives data such that the next one works for 16 weeks, and the one after that for 3 months, until this is a standard source of transplant organs.
- Aeolun 4y agoAh well, if you’ll likely die tomorrow then even 7 weeks is pretty good. Not sure that’s a good trade for the pig though.
- _ph_ 4y agoGood question. Maybe not, maybe actually yes. Using animals for transplants gives place for all kind of discussions. But this pig only existed as it was raised for that purpose. Like basically all pigs, which are raised for meat production. In contrast to those, the pig in question was probably well raised in good conditions and fed quality food and no bad pharmaceuticals. And indeed, humans use many animals, a lot of that use involves their deaths. But here it at least isn't for some random food, and a lot of meat just goes waste, but to keep a human alive. That is at least a very good reason.
- typest 4y agoThe heart is fundamentally a pump. Are we not able to build a replacement? I understand it’s not simple at all, and that people have tried and failed in the past, but is an artificial heart something that we should be able to build?
- davikr 4y agoIt might be a significantly hard problem: for instance, artificial heart valves tend to get infected by bacteria, and if it were the case for a whole artificial heart to get infected, perhaps it could spread and cause damage to the mediastinum (or), maybe, sepsis.
- DoreenMichele 4y agoSignificantly, the body does a poor job of fighting infection that occurs in artificial heart valves.
- trasz 4y agoWhy?
- DoreenMichele 4y agoFrom what I have read, artificial heart valves, being artificial, are simply not really covered by the immune system. In other words, you get white blood cells to the point of infection because you have blood supply and mechanical parts don't have blood vessels running through them. It's foreign matter, not really part of a living body. Very likely, they probably also attract infections that like eating plastics and such. These are inherently hard for the human body to combat if they get traction, from what I gather. They aren't a normal infection in humans and tend to be deadly when they do take root.
- madelyn 4y agoArtificial hearts already exist. But they usually are only used while waiting for transplants, because they're not as good as the real deal. Hearts are critical infrastructure in the body, with 100% uptime requirements and not-insignificant energy consumption.
- rob_c 4y agoSo completely reliable virus testing there because we now from the last 2 years that's 100% reliable. Clearly did a full genomic sequencing...
- ogogmad 4y agoWhat made the patient so unwell? I can't access the original paper. [edit] A 57-year-old man with chronic mild thrombocytopenia, hypertension, nonischemic cardiomyopathy, and previous mitral valve repair was hospitalized for severe heart failure with a left ventricular ejection fraction (LVEF) of 10%. His care was escalated to include multiple intravenous inotropic agents, and the placement of an intraaortic balloon pump was added on hospital day 11. Despite these measures, he had multiple ventricular arrythmias with arrests leading to resuscitation and began to receive peripheral venoarterial extracorporeal membrane oxygenation (ECMO) on hospital day 23. Sad.
- Aeolun 4y agoThat was before the transplant. Things were arguably a bit better for 7 weeks afterwards.
- bluedino 4y agoTransplanting organs is an amazing feat of science. However, how does it make any financial sense? This one of those things that makes sense to cut when you start talking universal healthcare, right?
- DoreenMichele 4y agoIt makes for razzle dazzle headlines. That seems to keep it alive. I wish there was more emphasis on helping people keep their original equipment from the manufacturer, so to speak.
- sokoloff 4y agoThere are a lot of surgeries and novel treatments that don’t make any financial sense. We don’t make healthcare decisions on a P&L basis, but hopefully on some kind of cost vs expected benefit to the patient basis. Transplanting a kidney or liver into a 20 year old has more of my support than transplanting a heart into an 85 year old.
- maxerickson 4y agoThe financial sense comes down to how you are measuring the value provided, there's not a single objective way to do it. Systems that use QALYs still often end up considering organ transplants a viable treatment.
- Qem 4y agoPeople suffer accidents, and in absence of donation, perfectly fine organs would just rot with them in the grave. With transplants, we take these organs that would otherwise be wasted, and give other people maybe years or decades of additional productive life. The overall economic impact must be overwhelmingly positive to society as a whole.
- DoreenMichele 4y agoAccording to the web site Transplant Living, created by the United Network for Organ Sharing, the average total cost for the first year for a double lung transplant costs $657,800. And then you take immunosuppressive drugs the rest of your life. https://www.chron.com/neighborhood/katy/news/article/The-cost-of-an-organ-transplant-9452184.php https://www.chron.com/neighborhood/katy/news/article/The-cos... Also, bear in mind the FTA is about an artificially engineered pig heart, not a human heart.
- DoreenMichele 4y agoBut the reason for that death isn't clear, and the typical signs of rejection by the immune system weren't present. Perhaps because it involved a pig heart, not a human heart? If this is new territory, I see no reason to expect failure to follow "typical" patterns.
- rdmirza 4y agoThat’s a great thought, however, when you look at tissue under a microscope you should see evidence that the immune system was at play. This means the presence of complement activation (an ancient arm of the immune system), antibodies, white blood cells, nuclear debris, and so on. Presumably when they saw no evidence of immune mediated rejection, they saw none of this.
- DoreenMichele 4y agoMy lay person understanding as someone with a condition where people get a lot of transplants is that we don't actually know what causes rejection. Perhaps in some cases the organ contains unidentified infective agents, thus the typical pattern with white blood cells etc. Perhaps in this case the body decided it was straight up foreign matter and the process of failure was fundamentally different.
- balanoceous 4y agoYour point that this is uncharted territory is well-taken, we can't say for sure, but the above poster has it right. I do not know of any circumstance in medicine in which evidence of immune reaction against foreign material would be non-obvious. I'm a pathologist and this is my area of expertise.
- DoreenMichele 4y agoTo be clear, I have two points: 1. This is uncharted territory. 2. My understanding is we don't actually understand "normal" rejection all that well to begin with. If we don't know how and why rejection occurs to begin with, we have no reasonable means to distinguish it from some other type of failure. But I shall stop annoying professionals with my amateur opinions here. Have a good day.
- u1tron 4y ago
- krapp 4y agoWe "temper and replace" body parts that "God created" all the time, including hearts. WTF are you even on about?