Human-Pig Embryos May Pave Way For Interspecies Organ Transplants

Scientists recently managed to grow an embryo that is part-pig and part-human by injecting human stem cells into a pig embryo, then implanting the embryo in the uterus of a sow, where it was left to grow.

Four weeks later, the stem cells developed into various tissue types, including the heart, liver and even neurons, with a small fraction of the pig being made up of human cells. According to The Washington Post, they hybrid has since been labeled as the "chimera," after the mythical creature with the lion's head and goat's body, with a serpent's tail. However, the researchers cautioned that the animal is "highly inefficient" despite being one of the most successful hybrids yet created. The chimera is considered a significant step toward developing animal embryos with functioning human organs.

Further report from USA Today stated that the researchers used less than one human cell in every 100,000 embryonic cells, which comes to about 1 million human cells on the animal. While the contribution is lower than expected, it was still considered a victory that they were able to detect human cells after four weeks of development.

Hiromitsu Nakauchi of Stanford University explained that his own unpublished experiments with pig and sheep embryo found little contribution from human cells, which makes it a challenge for making organs for transplant.

There have also been questions on ethics to the approach, as this could easily lead to pigs gaining human qualities in their brains, or make human eggs or sperm. "It seems kind of creepy," Insoo Hyun, from the Case Western Reserve University in Cleveland, said. "This is a strategy to help save human lives" and so it is justified if properly done, he said. Today, there is no sign of that. However, the government has signaled that it could lift the federal funding ban on such development. There has to be extra oversight to any further works, though.