Pigs set to replace lab-rats for human organ production

Tubby puppers (Photographer: Annie Kavanagh)

by Emily Murray

Moving in from growing human ears onto rats, scientists have now moved onto growing larger human organs, and larger organs means bigger animals.

Due to their size and shape pigs have been selected to become human organ incubators. The human-pig hybrid will contain human organs and tissue that will also functionally work in the human body. Scientists hope that this will aid the supply of organ donation, giving the organs to hospitals to use for transplants.

Scientists created an embryo of the human-pig, a “chimera”, which they terminated before it could be born. The research therefore is inconclusive, however pigs that possess human organs suitable for human donation might very well be the future.

The chimeras might also over take other animals, like rats, as the preferred animal to test drugs on. The part-human fabric of the animal means that it would provide the same response as a human would to the drug. Therefore providing more reliable results on the effectiveness and effects of the drug.

The scientists who worked on the embryo admitted that it was more challenging than they predicted. The scientific journal Cell published their report, which stated that mixing pig and human DNA together took decades to achieve. Challenges lie in trying to turn stem cells in petri dishes into functional adult cells, let alone trying to form the types of organs and tissues they set out to construct.

It is one thing to build the organs, and another to ensure that they function fully. Professor Izpisua Belmonte used the analogy of a key to convey the difficulties he experienced, “It’s like when you try to duplicate a key. The duplicate looks almost identical, but when you get home, it doesn’t open the door.” He admits, “We still have many things to learn about the early developments of cells.”

The research began by looking at whether they could introduce rat cells into mouse embryos. The rat-mouse chimera was successful and in 2010 they were able to create a mouse which had pancreatic tissue from a rat.

How the process works: gene-editing tools remove certain genes that build the organs in a growing egg. As the genes are removed they inject rat cells into the egg, immediately filling their space. The mouse embryo then continues to grow with the heart, eye or pancreas of a rat.

A work in progress, but the future looks promising for the chimera half pig half human bread.