Xenotransplant << ZEHN oh TRANS plant >> is the transfer of cells, tissues, or organs from one species into another. Medical researchers are actively investigating the use of nonhuman animal organs to replace diseased or damaged organs in human beings. Scientists hope the animal organs will one day help save human lives by increasing the supply of organs available for transplant.
Scientists have experimented with xenotransplants using organs from baboons and chimpanzees, but most believe pigs are a better choice. Pig organs are about the same size as adult human organs and, because pigs are raised for food, most people can accept killing them to save human lives.
The immune system normally rejects transplanted organs. An organ from another species causes a strong reaction called hyperacute rejection. The transplanted organ turns into a black, swollen mass and dies within minutes. To prevent rejection, scientists are experimenting with transgenic pigs, which are created by injecting human genes into pig embryos. Transgenic pigs have organs coated with human proteins that trick the human immune system into mistaking them for human organs.
Many medical experts are concerned that xenotransplants will allow animal viruses to spread to people. Pigs naturally carry several viruses that could be transformed and infect human beings through transplanted organs. These viruses may endanger the organ recipient and could possibly infect others.
In 2017, scientists used a genetic engineering technique called CRISPR to remove viral genetic material from pig cells. Scientists can use CRISPR to delete, alter, or replace genetic material within a cell with great accuracy. The altered pig cells were then used to create several clones. A clone is a genetically identical copy of an organism. The genetically altered pigs did not carry any of the viruses that naturally occur in pigs.
The first successful xenotransplants of whole organs were performed in the early 2020’s. In 2022, surgeons transplanted a heart from a genetically modified pig into a 57-year-old male patient. The heart kept the patient alive for two months.
