The long-term goal is to optimize the technology for human organ transplantation.
The kidney breakthrough is the first time that scientists have been able to grow a solid “humanized” organ inside another species,
When transferred into surrogate pig mothers, the Chinese team say the developing kidneys had normal structure and tubule formation after 28 days.
Previous studies have used similar methods to generate human tissues such as blood or skeletal muscle in pigs.
The Guangzhou Institutes of Biomedicine and Health team, whose ground-breaking work was published in the journal Cell Stem Cell, concentrated on kidneys because they are one of the first organs to develop, and they’re also the most commonly transplanted organ.
Senior author Professor Lai Liangxue said: “Rat organs have been produced in mice, and mouse organs have been produced in rats, but previous attempts to grow human organs in pigs have not succeeded.
“Our approach improves the integration of human cells into recipient tissues and allows us to grow human organs in pigs.”
The hybrid kidneys. PHOTO BY SWNS
He explained that integrating human stem cells into pig embryos has been a “challenge” because pig cells outcompete human cells and pig and human cells have different physiological needs.
Senior author Professor Guangjin Pan said: “We have been working on mechanisms to overcome the extremely low efficiency in interspecies chimera.
The team also investigated whether human cells were contributing to other tissues throughout the embryos, which could have ethical implications, especially if abundant human cells were found in neural or germline tissues and the pigs were brought to term.
They showed that human cells were mostly localized to the kidneys, whereas the remainder of the embryo was composed of pig cells.
Now they’ve optimized conditions for growing humanized kidneys, the Chinese scientists want to allow the kidneys to develop for a longer duration.
In the study, the researchers created a niche for only one subset of cells, which meant that the kidneys had pig-derived vascular cells, and that could cause organ rejection if they were used in a transplant scenario.
Study senior author Dr. Miguel Esteban said: “Because organs are not composed of just one cell lineage, in order to have an organ where everything comes from the human, we would probably need to engineer the pigs in a much more complex way and that also brings some additional challenges.”
He added: “Before we get to that late state of making organs that can be on the shelf for clinical practice, this method provides a window for studying human development.
“You can trace the human cells you’re injecting and manipulate them so that you can study diseases and how cell lineages are formed.”
Produced in association with SWNS Talker