Human-pig hybrids may provide donor organs

SCIENTISTS have created the first human-pig hybrids in a breakthrough that could pave the way for doctors to grow an unlimited supply of organs for transplants.

In the past, scientists thought they might be able to use the organs of pigs, which are about the same size as those of humans, but they could not prevent the immune system rejecting animal tissue.

An alternative was to use stem cells — which can become any cell in the body — and grow new organs in the lab. But scientists have struggled to coax stem cells into complex 3-D structures.

Now a team at the Salk Institute in the US has combined both concepts and shown it is possible to grow human tissue in a pig. It took four years, 1 500 pig embryos and the stem cells from 40 people.

“We underestimated the effort involved,” said lead investigator Professor Juan Carlos Izpisua Belmonte. “This is an important first step. Our next challenge is to guide the human cells into forming a particular organ in pigs. The ultimate goal is to grow functional and transplantable tissue or organs.”

Scientists first created a ratmouse hybrid by introducing rat cells into mouse embryos to see if animals could develop using the DNA of another species. The team then genetically edited out part of the mouse DNA.

The rat cells completed areas that were missing in mouse DNA, forming a rat heart, eyes and pancreas within the mouse.

The team then set about introducing human cells in pigs, a far more complicated procedure. They used the CRISPR technique, which

Idea of creating human-animal hybrids has met ethical opposition

works like molecular scissors to snip away parts of DNA code that are not wanted.

The human cells survived and formed a human-pig hybrid embryo, which was then implanted into a sow and allowed to develop for three to four weeks.

The idea of creating humananimal hybrids has met ethical opposition, with some claiming scientists are creating monsters. — ©