In a bid to alleviate the country’s organ shortage, scientists are modifying pig livers to look and act like human ones.
Workers at a lab in suburban Minneapolis dissolve organ-functioning pig cells, leaving semi-transparent scaffolds floating in large jars. To complete the metamorphosis, they fill those shells with human cells from a non-transplanted donor liver.
The process is highly experimental, but the manufacturer, Miromatrix, plans to conduct the first phase of a human trial — an experiment outside a patient’s body to see how well the bioengineered liver filters blood.
“We’re essentially regrowing an organ,” said Miromatrix CEO Jeff Ross. “Our body no longer sees it as a pig organ.”
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A technician changes the medium in bioreactors containing pig kidneys at the Micromatrix Laboratory in Eden Prairie, Minn., Tuesday, Dec. 8, 2022.
(AP Photo/Andy Clayton-King)
Miromatrix plans to begin human trials of the bioengineered organ in 2023 to begin trying to prove it.
If the Food and Drug Administration approves, the initial experiment will be conducted outside the patient’s body. Researchers are placing a pig-like human liver next to a hospital bed to temporarily filter the blood of a person whose liver has suddenly stopped working. And if this novel “liver support” works, it will be an important step toward transplanting a bioengineered organ—perhaps the kidney.
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A technician holds a “woven” pig liver at the Micromatrix lab in Eden Prairie, Minneapolis, Tuesday, Dec. 8, 2022. The first step for suburban lab workers in Minneapolis is to shampoo the pig cells. This forced the organ to do its job, its color gradually faded as the cells melted and reddened. What remains is a rubbery scaffold, the honeycomb structure of the liver, its blood vessels now empty.
(AP Photo/Andy Clayton-King)
“It all sounds like science fiction, but it has to start somewhere,” said Dr. Sander Florman, chief of transplantation at Mount Sinai Hospital in New York. “It’s probably a more immediate future than xenotransplantation,” or the direct implantation of animal organs into humans.

A label on a bioreactor shows a porcine kidney Tuesday, Dec. 8, 2022, at Micromatrix Laboratories in Eden Prairie, Minn.
(AP Photo/Andy Clayton-King)
More than 105,000 people are on the waiting list for an organ transplant in the US. Thousands die before their turn. Thousands of people will never be listed, which is considered too long.
“The number of organs we have will never meet the demand,” said Dr. Amit Tewar, a transplant surgeon at the University of Pittsburgh Medical Center. “That’s our disappointment.”
The Associated Press contributed to this report.