Making pig livers humanlike in quest to ease organ shortage

EDEN PRAIRIE, Minn. (AP) -- The ghostly form floating in a large jar had been the robust reddish-brown of a healthy organ just hours before. Now it’s semitranslucent, white tubes like branches on a tree showing through.

A pig liver that has been “decelled” is held by a technician in a Micromatrix laboratory on Tuesday, Dec. 8, 2022, in Eden Prairie, Minn. --Photo AP

This is a pig liver that’s gradually being transformed to look and act like a human one, part of scientists’ long quest to ease the nation’s transplant shortage by bioengineering replacement organs.
The first step for workers in this suburban Minneapolis lab is to shampoo away the pig cells that made the organ do its work, its color gradually fading as the cells dissolve and are flushed out. What’s left is a rubbery scaffolding, a honeycomb structure of the liver, its blood vessels now empty.
Next human liver cells taken from donated organs unable to be transplanted will be oozed back inside that shell. Those living cells move into the scaffolding’s nooks and crannies to restart the organ’s functions.
“We essentially regrow the organ,” said Jeff Ross, CEO of Miromatrix. “Our bodies won’t see it as a pig organ anymore.”
That’s a bold claim. Sometime in 2023, Miromatrix plans first-of-its-kind human testing of a bioengineered organ to start trying to prove it.
If the Food and Drug Administration agrees, the initial experiment will be outside a patient’s body. Researchers would place a pig-turned-humanlike liver next to a hospital bed to temporarily filter the blood of someone whose own liver suddenly failed. And if that novel “liver assist” works, it would be a critical step toward eventually attempting a bioengineered organ transplant — probably a kidney.
“It all sounds science fiction-ey but it’s got to start somewhere,” said Dr Sander Florman, a transplant chief at New York’s Mount Sinai Hospital, one of several hospitals already planning to participate in the liver-assist study. “This is probably more of the near future than xenotransplantation,” or directly implanting animal organs into people.
More than 105,000 people are on the US waiting list for an organ transplant. Thousands will die before it’s their turn. Thousands more never even get put on the list, considered too much of a long shot.
“The number of organs we have available are never going to be able to meet the demand,” said Dr Amit Tevar, a transplant surgeon at the University of Pittsburgh Medical Centre. “This is our frustration.”
That’s why scientists are looking to animals as another source of organs. A Maryland man lived two months after receiving the world’s first heart transplant from a pig last January  an animal genetically modified so its organs didn’t trigger an immediate attack from the human immune system. The FDA is considering whether to allow additional xenotransplantation experiments using kidneys or hearts from gene-edited pigs.

(Latest Update December 29, 2022)