Scientists have recently tried to create a chimera by injecting human stem cells into a pig embryo. The purpose of this experiment is to address the shortage of donor organs and see if they could be grown within a non-human organism.

Namely, these organs would be used in future for organ transplantations into human beings who will technically be a part pig, known as chimeras.

Chimera can be created into 2 ways. The first one is by transplanting organs from one species to another but the risk of rejection here is very high. The second one is by injecting human cells into a non-human embryo so that they can grow together with the embryo and thus form a hybrid.

The scientists of the Salk’s Institute’s Gene Expression Laboratory have been trying 4 years to enable the human cells and the pig embryo to grow together and survive without rejection.

According to them, humans and pigs have very similar organs but the gestation period of pigs is much shorter which implies that the transplanted organs will grow faster.  

The scientists have created 186 later-stage human-pig embryos that survived. They have estimated that each embryo was made up of 0.001% human cells. This percentage is extremely low which means that human-pig embryos took much longer to develop.

The research has also shown that human cells can develop fully functioning organs alongside pig cells. Scientists hope that in future they will be able to create human-compatible organs in this way.

Once the percentage increases enough so that the hybrid organs will not be rejected by humans, many ethical questions will be raised.

In meantime, according to the researchers, creating chimeras with human tissue could be used for:

  • Understandingthe earliest stages of the embryo development in humans
  • Studying thegenesis of human diseases
  • Screening drugsbefore human trials
  • Explaining thedifference between organs in different species