Stem cells successfully transformed into liver cells

In a breakthrough, scientists have discovered a novel way to transform skin cells into mature, fully functioning liver cells that can flourish on their own.
The results offer new hope for millions of people suffering from, or at risk of developing, liver failure.
At present, the only option is a costly liver transplant. So, scientists have long looked to stem cell technology as a potential alternative.
Scientists at the Gladstone Institutes and University of California, San Francisco (UCSF) found the way to transform skin cells into mature, fully functioning liver cells that grow on their own, even after being transplanted into laboratory animals modified to mimic liver failure.

In previous studies, scientists had difficulty getting stem cell-derived liver cells to survive once being transplanted into existing liver tissue.
But the team figured out a way to solve the problem, revealing a new cellular reprogramming method that transforms human skin cells into liver cells that are virtually indistinguishable from cells that make up native liver tissue.

The research involved using a 'cocktail' of reprogramming genes and chemical compounds to transform human skin cells into cells that resembled the endoderm.
Endoderm cells are cells that eventually mature into many of the body's major organs - including the liver.
"Instead of taking the skin cells back to the beginning, we took them only part way, creating endoderm-like cells," said Saiyong Zhu, one of the research paper's lead authors.

"This step allowed us to generate a large reservoir of cells that could more readily be coaxed into becoming liver cells," said Zhu.
The researchers then discovered a set of genes and compounds that can transform these cells into functioning liver cells.
"The cells began to take on the shape of liver cells, and even started to perform regular liver-cell functions," said Milad Rezvani, the paper's other lead author.
"They weren't fully mature cells yet - but they were on their way," said Rezvani.
The team wanted to see what would happen in an actual liver so, they transplanted these early-stage liver cells into the livers of mice.

Over a period of nine months, the team monitored cell function and growth by measuring levels of liver-specific proteins and genes.
Two months post-transplantation, there was a boost in human liver protein levels in mice, indicating the transplanted cells were turning mature functional liver cells.
Nine months later, cell growth had shown no signs of slowing down. The results indicate that researchers have found the factors required to successfully regenerate liver tissue.
The study was published in the journal Nature.