Scientists have successfully grown early kidney structures made of mostly human cells in pig embryos for up to 28 days. This research, conducted by Miguel Esteban and his colleagues at the Guangzhou Institutes of Biomedicine and Health in China, aims to address the shortage of organ donors by growing human organs in other animals for transplants. Currently, over 100,000 people in the US alone are waiting for a kidney transplant, with 13 dying per day.
To achieve this, the researchers created pig embryos that couldn't form kidneys by disabling two key genes responsible for organ development. They then introduced human stem cells into the embryos, genetically engineering them to increase their integration into the pig environment. These hybrid human-pig embryos were implanted into 13 sows, with only five successfully developing early kidney structures made of 50 to 65 percent human cells.
The researchers have received approval to continue their study, allowing the human-pig embryos to develop for up to 35 days to monitor the maturation of the humanized kidneys and ensure minimal human cells in other organs. They also plan to explore growing other human organs like the heart and liver in pigs.
In addition to this approach, other groups are working on using pig-only organs for transplantation. Surgeons at NYU Langone Health recently successfully transplanted a pig kidney into a brain-dead man, using an animal with a gene knocked out to prevent an immune reaction. The kidney has been functioning properly for almost two months.
Jun Wu at the University of Texas Southwestern Medical Center, who worked on the creation of the first human-pig embryos in 2017, believes that a combination of growing mostly human kidneys in pigs and knocking out genes that may trigger immune reactions could be the most effective approach.
While this research shows promise in addressing the organ shortage, ethical considerations, such as the possibility of producing pigs with human-like brains if human cells spread beyond the kidneys, limit the length of embryo development. Nevertheless, these findings represent a significant step forward in the field of organ transplantation and may offer hope to those in need of a kidney transplant.