VATIS UPDATE Article

According to a study, scientists have for the first time grown embryos that contain a combination of pig and human stem cells, in a step toward one day growing transplantable organs. However, the research remains at a very early stage and proved more difficult than expected. “This is an important first step. The ultimate goal is to grow functional and transplantable tissue or organs, but we are far away from that,” said Juan Carlos Izpisua Belmonte, at the Salk Institute of Biological Studies, the United States.

Scientists implanted adult human stem cells – known as intermediate induced pluripotent stem cells – into pig embryos and allowed them to grow for four weeks. They terminated the embryos before any human-animal mixture, known as a chimera after the cross-species figures of Greek mythology, could be born. They found that the human cells began to form into muscle tissue in the pig embryos.

The effort involved some 1,500 pig embryos and took four years, far longer than intially estimated, due to the complicated nature of the experiments. The notion of creating human-animal mixtures has stoked controversy and raised ethical questions, particularly since the experiments could theoretically lead to the creation of animals with human qualities, and possibly intelligence. Previous research has produced combinations of rats and mice, which are far more closely related.