This bag of cells can grow new livers inside people

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In early experiments, Lagasse found that if he injected healthy liver cells into the lymph nodes of mice, the cells would proliferate and form a second, smaller liver to take over the functions of the animal's failing liver. The new livers grew to 70 percent the size of the native livers. “What happened was that the liver grew to a certain size and then stopped growing when it reached the level needed for normal function,” says Lagasse.

At the University of Pittsburgh, Lagasse and colleagues also tested this approach in pigs. In a study published in 2020, they found that pigs regained liver function after injecting liver cells into an abdominal lymph node. When scientists examined lymph nodes along with a miniature liver, they found that a network of blood vessels and bile ducts had spontaneously formed. The more severe the damage to the pigs' original liver, the larger the second liver grew, suggesting that the animals' bodies may be able to recognize healthy liver tissue and transfer responsibilities to it.

“It is remarkable to identify lymph nodes as a reproducible and fertile bed for the regeneration of a variety of tissues and organs in two different animal species,” says Abla Creasy, MD, vice president of therapeutic development at the California Institute for Regenerative Medicine. ” Company's perspective. “These findings suggest that such an approach could offer an alternative tissue source for patients with dysfunctional organs,”

Elliot Tapper, a liver expert at the University of Michigan, is also excited by the possibility of turning lymph nodes into new livers. “Even though it's not where the liver was supposed to sit, it can still perform some of the functions of the liver,” he says.

He says the most likely benefit of lygenesis treatment will be removal of ammonia from the blood. In end-stage liver disease, ammonia can accumulate and travel to the brain, where it causes confusion, mood changes, deterioration, and sometimes coma. However, they do not think the new tiny organs can perform all the functions of a natural liver, because they contain other types of cells besides hepatocytes.

One of the big questions is how many cells humans would need to develop a liver large enough to handle certain vital functions, such as filtering blood and producing bile. In the Lygenesis trial, three additional patients will receive an injection of 50 million cells into the same lymph node — the lowest “dose.” If it seems safe, a second group of four will inject 150 million cells into three different lymph nodes. The third group would get 250 million cells in five lymph nodes – meaning five mini livers could grow inside them.

The effects of the therapy will not be immediate. Hufford says it will take two to three months for the new organ to grow large enough to take over some of the functions of the native liver. And like organ donor recipients, trial participants will need to go on immunosuppressant drugs for the rest of their lives to prevent their bodies from rejecting the donor cells.

If the approach works, it could provide a life-saving alternative to liver transplantation for some patients. “If they prove that it's effective and safe, there will certainly be candidates who are interested in this type of intervention,” says Tapper.