In the United States alone, more than 100,000 people are now waiting to receive organ transplants. Most of these people need a kidney transplant. To meet this demand, scientists have conducted many studies on new methods of growing organs and tissue inside the body of animals. Advances in recent years have included growing rat organs in mice (and vice versa) and growing human skeletal muscle and endothelial tissue in pigs.
One of the obstacles facing the cultivation of human organs and tissues inside the body of animals is that human cells do not survive in a foreign host. Induced pluripotent stem cells (iPSCs), which serve as a kind of starter kit for the growth of many types of human tissues, are often destroyed when introduced into animals; Because they have different physiological needs.
A group of researchers from the Guangzhou Institute of Biomedicine and Health in China have worked for more than five years on ways to increase the longevity of human stem cells in the body of other species.
to report Science News, scientists inserted human stem cells into pig embryos that had been engineered to lack kidneys. The stem cells in the body of the embryos differentiated and became a new organ, which was mostly composed of human cells.
More specifically, while the pig embryos were still in the single-cell stage, the researchers used the CRISPR gene editing tool to delete two genes required for kidney development. Thus, an environment was created in which human stem cells could differentiate into kidney cells after injection. The human stem cells were also modified to have active genes to inhibit cell death and allow the cells to survive long enough to begin kidney formation.
More than 1,800 embryos were transferred to female pigs and five of them were removed for study at 28 days. All five embryos had normal kidneys consistent with their developmental level, and the kidneys contained 60-60% human-derived cells. The researchers say that the kidneys will probably continue to grow, and the number of human cells will still be higher than pig cells.