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Last week, researchers announced that they’d implanted the heart of a transgenic pig into a baboon, and kept it alive for a year.  Here’s why you should care:

One day, a few decades from now, you are going to need a new organ.  Maybe a heart, maybe new lungs, maybe a new kidney — they all eventually wear out.   Heart disease is the leading cause of death worldwide.

The median age of a heart attack victim is only 50 years old.  You can subtract your age from that number to see how long you have left for medical science to figure out a way to make new organs — because the supply from organ donation is not keeping up with demand.

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Experiments like the heart study may provide a way to solve the problem.  The plan is to eventually create pigs engineered to produce organs for transplantation into humans, a process called xenografting.

NIH researchers at the National Heart, Lung and Blood Institute were able to modify pigs not to express a series of marker proteins that trigger a response from primate immune systems. Those responses would normally cause rapid and severe rejection in humans and baboon transplant recipients.  Additionally, some of the pigs were genetically engineered to produce specific proteins intended to reduce blood clotting, another common cause of transplant failure (a syndrome known as “acute vascular rejection”).

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This represents a major step forward in the ability for scientists to genetically engineer the immune system of animals. If perfected, this might allow doctors to produce organs tailored to the immune systems of individual people, so that the recipient body treats the new organ as native tissue.

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This is important because, even in the case of human-human transplants, there are plenty of rejection problems.  Even for those who do get a donor organ in time, the immune suppression drugs that patients have to take to avoid their immune system killing the organ are nightmarish, and don’t even completely work. Donor kidneys only survive for a decade or two.

What doctors really want is the ability to make completely new organs from the patient’s own tissue.  If doctors had a limitless supply of transgenic pig organs, they could pre-emptively replace organ systems before they fail, and treat cancer by simply removing and replacing every piece of tissue that might be affected.

One approach to making new organs is 3D printing a collagen scaffold, and then growing stem cells into it.  We’ve covered the technology before 5 Amazing TED Talks That Will Change How You Think About Medicine 5 Amazing TED Talks That Will Change How You Think About Medicine These five TED talks give us hints about cutting edge scientific research, and the quality of life that we might one day experience Read More (and you can watch a TED talk about the process below).

3D printing has a lot of issues. The resolution is pretty limited right now, making it difficult to build the fine structure of organs like lungs.  On top of that, many organs are composed of a lot of different kinds of interwoven tissue, and it’s difficult to get stem cells to grow properly in the correct shapes.  It’ll be a while before scientists can make everything through 3D printing.

The organ study shows a way around a lot of these problems.  Doctors could simply grow pigs with the genes of their patients to maturity, kill the pig, vitrify the organs, and have them ready when they’re needed.  Any organ (or even potentially some bones) would be available on demand as needed.

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The baboon study was a promising first step, although significant challenges remain.

For starters, the hearts were not serving as functioning organs for the baboons — they were simply implanted into the body cavity to see if they’d survive.  Testing their cardiac function will follow in future experiments to see if the organs are viable.  However, initial results are promising: of the organs with all the modifications, the median survival rate was 200 days, and three of the five organs were still alive at time of publication.

If researchers can prove that the organs are viable organ replacements in baboons, the road ahead is clear for clinical trials in human subjects.  If all goes well, in ten or twenty years, the technology might be ready to make donor-specific organs for anyone and everyone. One of the researchers responsible for the breakthrough, Dr. Mohiuddin, was optimistic:

Xenotransplantation could help to compensate for the shortage of human organs available for transplant. Our study has demonstrated that by using hearts from genetically engineered pigs in combination with target-specific immunosuppression of recipient baboons, organ survival can be significantly prolonged. Based on the data from long-term surviving grafts, we are hopeful that we will be able to repeat our results in the life-supporting model. This has potential for paving the way for the use of animal organs for transplantation into humans.

Is it possible that some day the genetic engineering or 3D printing of new organs will become the norm, while organ transplants will become an archaic relic of medical history? Will most of us have genetically engineered replacement organs in our retirement years? Share your own thoughts on this breakthrough science in the comments section below.

Image Credits: Human heart Via Shutterstock, “Pig“, Peter Pearson, “Untitled“, Charlotte Astrid, “06410062“, IEAE ImageBank

  1. Tom W
    August 31, 2014 at 5:10 pm

    In the UK, it's usually a first diagnosis by the imediate medical team, followed by a full assessment from a psychiatric professional. I believe that the next of kin then has the responsibility of deciding on treatment, or lack thereof. Only when the next of kin is unable to be contacted or unable to make a decision do the doctors make the judgement call. I could be wrong, it's not an area that I have a huge amount of experience in. Obviously the system is flawed, but it sounds like the US has it worse off. This is what happens when judicial systems get too old, and don't reflect the changes in society that have happened since the systems were put in place.

  2. dragonmouth
    August 30, 2014 at 9:11 pm

    I notice no mention of the ethical problems involved.

    Members of Judaism and Islam are by definition forbidden from partaking in this miracle since it involves a pig, an unclean animal. Members of some Christian sects, such as the Roman Catholics, may have serious qualms about accepting pig organ transplants, especially hearts, on the grounds of what effect that may have on their immortal souls. Jehova's Witnesses and other groups are forbidden by their beliefs to even accept blood transfusions, let alone transplants.

    While this is a great advance in medicine, it will create a virtual ethical Gordian knot.

    • Andre I
      August 30, 2014 at 9:21 pm

      They'll get over it. It's not the job of science to avoid life-saving therapies because they offend old superstitions.

    • dragonmouth
      August 30, 2014 at 10:15 pm

      "They’ll get over it."
      I doubt that very much. These "old suprestitions", as you flippantly call them, have been around for thousands of years and many people have died and will die defending them. Obviously you are not religious, neither do you have much regard for points of view other than your own arrogant one.

      "It’s not the job of science to avoid life-saving therapies "
      I agree. it is not. However, one must recognize the ethical problems the life-saving therapies create.

    • Tom W
      August 30, 2014 at 11:17 pm

      If this does become viable in humans, it can be used to treat every human who doesn't have a moral or ethical opposition to it. The rest of the people can either use human organs, which will now be under much less demand, or they can use 3D printed organs, which will hopefully be much improved by then. There will be some people who don't like any of the above options, but hopefully a new, as yet unthought of, solution comes along that aligns with their beliefs. Or they make peace with the situation, which isn't unlikely.

    • dragonmouth
      August 31, 2014 at 1:53 pm

      "If this does become viable in humans...."
      Make that "when" not "if".
      Don't get me wrong, I am all for it and any other medical advancements. However, even now there are ethical dilemas facing doctors and hospitals in critical cases. Do they respect the moral/religious beliefs of the patient and family, not perform the required procedure (ex. transfusion) and let the patient die OR, as has happened, get a court order forcing the procedure to be performed and save a life and then face civil suits? Then the matter is further complicated by busybody do-gooders who claim to have a direct line to God and insist on imposing their beliefs on the rest of the world.

      "every human who doesn’t have a moral or ethical opposition to it."
      As of right now, those who could benefit but would have morel or ethical opposition number between 2 and 3 Billion. That is a significant percentage of world's population.

    • Tom W
      August 31, 2014 at 2:37 pm

      As the law stands in the UK, and probably many other countries, a patient of their right mind has the right to refuse any treatment, even if the alternative is death or extreme pain. A doctor can override this with a mental health order if the situation calls for it, and they can also override it if they deem the situation has changed sufficiently and the patient isn't able to communicate their wishes. I would hope that doctors respect the wishes of their patients in these situations, but that's a whole other discussion.

      If 3 Billion people decide that they do not wish this treatment, then they are in no worse situation than they are right now. It's their choice. Science, driven by people with experience in medicine, ethics, and theology, may or may not come up with a treatment that they choose to undertake. If they don't wish to receive any form of transplant then that's between them and their belief system.

    • dragonmouth
      August 31, 2014 at 3:21 pm

      "a patient of their right mind"
      Who defines "right mind"? The doctor? The family? The courts? Some religious group with an agenda?

      Can anybody who refuses treatment that will save them pain and suffering, or death, be considered "of their right mind?" The answer depends on one's personal beliefs. If one is a realist or a pragmatist then the answer is YES. However, if one is a deeply religious Right to Lifer, then the answer is a resounding NO and the life must be preserved by any and all means possible, regardless of the effect on quality of that life.

      In the US there have been instances where the patient or the family choose not to continue a treatment only to have some religious group pop out of nowhere, get the patient declared incompetent and the family declared incapable of making a "sound" decision because of emotional stress. Then they obtain a court order to continue the treatment. To add insult to injury, once the court order is in place, the group fades back into the woodwork, leaving the patient to face continued pain and suffering, and the family in distress over the loved one's suffering and facing mounting medical bills. Not once have I heard of the do-gooders taking on the responsibilities of being the patient's legal guardians.

    • Tom W
      August 31, 2014 at 5:10 pm

      In the UK, it's usually a first diagnosis by the imediate medical team, followed by a full assessment from a psychiatric professional. I believe that the next of kin then has the responsibility of deciding on treatment, or lack thereof. Only when the next of kin is unable to be contacted or unable to make a decision do the doctors make the judgement call. I could be wrong, it's not an area that I have a huge amount of experience in. Obviously the system is flawed, but it sounds like the US has it worse off. This is what happens when judicial systems get too old, and don't reflect the changes in society that have happened since the systems were put in place.

  3. michaelc
    August 30, 2014 at 6:38 pm

    "Experiments like the heart study may provide a way to solve the problem."
    Admittedly this does create a new problem for the pig.

    • Andre I
      August 30, 2014 at 9:25 pm

      Only a problem for one pig per person per 40 years or so. Less of a problem than, say, the McRib.

      It may also be possible to produce pigs that grow without brains or higher cognitive function to eliminate animal cruelty from the process entirely.

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