Functional Livers Created From Human Stem Cells
July 4, 2013

Functional Livers Created From Human Stem Cells

redOrbit Staff & Wire Reports - Your Universe Online

Researchers from Japan have reportedly used human stem cells to create functional human liver precursors similar to those found in fetuses, various media outlets reported on Wednesday.

Writing in the journal Nature, Takanori Takebe of the Yokohama City University Graduate School of Medicine and colleagues mixed a cocktail of induced stem cells (created from adult tissue) to grow human liver "buds" that were then implanted in mice, USA Today's Dan Vergano explained.

"These buds didn't grow into regular livers and any treatment for humans is at least a decade away," said Bloomberg reporter Elizabeth Lopatto. After being placed on the heads and abdomens of the rodents, they were able to process some of the drugs and compounds actual human livers can handle that are beyond the capabilities of mouse livers.

They did not function as well as a regular liver, but nonetheless "demonstrated the first steps toward potentially creating new organs for transplants," she added. Dr. Matthew Smalley, a senior lecturer at Cardiff University's European Cancer Stem Cell Research Institute who was not involved in the study, told Lopatto the research "holds out real promise for a viable alternative approach to human organ transplants."

The study authors were able to chemically recode human skin cells into induced pluripotent stem cells. They then treated those cells in such a way as to encourage them to grow into early-stage human liver cells, which are comprised of several different types of cells. Each of these cells are responsible for different tasks - including providing structure and blood vessels for the organ, Guardian Science Correspondent Ian Sample said.

They mixed the liver cells with two other types of human cells, including some from umbilical cords, to duplicate the effect. When they did so, Sample said, they were surprised to find the cells "arranged themselves into a ball as they grew, mimicking the earliest stages of liver growth in a human embryo... The clumps of cells grew rapidly for two months, at which stage they measured around five millimeters across."

After the buds were transplanted under the skins of the mice, they matured into what appeared to be adult liver tissue. To test their effectiveness, the rodents were given two different drugs - the anti-inflammatory ketoprofen and the high blood pressure drug debrisoquine. When they tested the animals' blood, they reportedly found breakdown products traditionally created by a human liver, not a mouse liver.

"It is thought that other organs such as the pancreas, kidneys and even the lungs could be developed in the same way. However, turning this into a treatment is still a distant prospect," BBC News Health and Science Correspondent James Gallagher said.

In fact, according to Reuters, it could take another ten years before lab-grown livers could be used to treat actual men and women. Nonetheless, Gallagher said, "This is a significant advance for the field of regenerative medicine. It might seem like science fiction but there are already people walking around today with organs made from stem cells... This is a new approach to growing solid organs and is yet another window on what could be the future of organ transplants."