Pig Livers Made Humanlike to Ease Organ Shortage

Scientists are working to transform pig livers to be more humanlike to help relieve the organ shortage in the United States.

Key takeaways:
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    To help with the organ shortage in the United States, scientists are working to transform pig livers to be more humanlike.
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    More than 100,000 Americans are currently on the organ transplant waiting list.
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    The Minneapolis lab Miromatrix will be the first to try this experimental method.
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    The first Miromatrix test on humans will be done outside of a patient’s body in a process called a “liver assist.”

By 2023, Minneapolis lab Miromatrix plans to begin testing bioengineered replacement livers from pigs on humans. The highly experimental process will be the first of its kind.

To begin, the lab researchers cleaned away the parts of the pig cell that made the organ work. The organ’s color fades during this process, and the cell breaks down. What remains is a semi-translucent, empty liver.

When the vessel is empty, scientists insert human liver cells. These living cells fill the gaps in the framework, making the liver function properly.

The Miromatrix method originated in the early 2000s when regenerative medicine expert Doris Taylor and Dr. Harald Ott of the University of Minnesota developed a method to decellularize the heart of a dying rat. The team, which made international news, successfully placed immature heart cells from baby rats into the dying rat.

“We’ve seen that pig organs can effectively be decellularized, leaving behind all of the organ’s natural design and architecture…which is a large step forward for regenerative medicine and tissue engineering,” Jeff Ross, Miromatrix CEO, said in an interview for Medical Alley.

Miromatrix and the Mayo Clinic transplanted bioengineered pig livers in 2021. From there, scientists tested "liver-assist" treatment, a process similar to dialysis that uses bioengineered livers to filter the blood of those with acute liver failure, a life-threatening emergency.

The Food and Drug Administration has approved decellularized pig tissue for other purposes, such as making surgical mesh. However, the FDA is still awaiting answers from Miromatrix about the application for the study.

If the FDA agrees to the Miromatrix study, the first test will be done outside a patient’s body. Researchers will put a pig's liver that had been changed to look like a human liver next to a hospital bed to filter the blood of someone whose own liver suddenly stopped working.

If this new "liver assist" works, it could be a step toward transplanting a bioengineered organ, perhaps a kidney, next.

The liver is unique as it’s the only organ that can regenerate. This may be why pig livers are the first to be tested this way, unlike other organs such as kidneys.

The news arrives amid major organ shortages in the U.S. Currently, more than 100,000 Americans are waiting for an organ transplant. In September 2022, the U.S. counted its millionth organ transplant, a historic milestone, according to the United Network for Organ Sharing (UNOS).

More people are receiving organ transplants. In 2021, the U.S. performed a record number of over 41,000 kidney, liver, and other organ transplants. Still, 6,000 died in 2021 while waiting for an organ transplant, according to the nonprofit Donate Life America. Critics continue to speak out against policies and hospital mistakes that lead to wasted organs.

At a 2022 senate committee hearing, lawmakers blamed UNOS, a nonprofit that holds a government contract to oversee the transplant system, for making it difficult to track organs.

“This is sitting on your hands while people die,” Senator Elizabeth Warren, D-Massachusetts, said to the UNOS CEO.

Since then, the National Academies of Sciences, Engineering, and Medicine (NASEM) have set a five-year deadline for improving every part of the complicated transplant system. This includes the groups that collect organs from people who have died, the transplant centers that decide which to use, and the government agencies that control both.

In the meantime, tests like the Miromatrix bioengineering replacement organs may help close the organ shortage gap.


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