Pig Pancreases for Humans

New technology may allow researchers to grow human organs inside of pigs. Professor Hiromitsu Nakauchi of the University of Tokyo presented the idea at a European genetics conference last month.

Nakauchi and his colleagues created genetic deficiencies in the embryos of mice so that the mice wouldn’t be able to grow pancreases. Then the scientists injected stem cells from rats into the mice embryos. The mice grew rat pancreases and were fine.

The Professor said that he now wants to create organ-deficient pig embryos, re-engineer adult human cells to act like stem cells, and inject the the cells into the embryos, causing the pigs to grow human organs. The pigs could then be slaughtered and their organs transplanted into a human patient. Since the patient’s own cells would be used to grow the organ, the patient would be less likely to reject the organ.

Scientists have been working on this idea for twenty years. The genetic manipulation of embryos has a number of oter applications, as well. Pigs with common genetic disorders like Type-1 diabetes could be developed and then used to find therapies for those disorders. "To combat swine flu, for instance, we could make a precise, gene-modified pig to improve the animal's resistance to the disease." Dr. Lei Xiao of the Chinese Academy of Sciences told the Daily Mail in 2009.

Other researchers have already created pigs with human blood. Earlier this month, scientists revealed that they had grown a mouse tooth in the mouse’s kidney, took the tooth out, and put it in the mouse’s mouth, at which point the tooth fused with the mouse’s other systems and functioned normally.

Researchers call the transplantation of organs between species “xenotransplantation.” It was originally an ancient Greek idea, though technology has only now begun to make it feasible. According to National Geographic, a Russian doctor healed a man’s skull fracture with a dog bone back in 1862. Today, human heart valves are often replaced with bovine and swine ones. Pigs are particularly good candidates for this procedure because they are so similar to humans.

The supply of human organs for transplantation has always run behind demand, leading to long waiting lists. Desire for organs also fuels shady underground organ markets. Professor Chris Mason of University College in London greeted Professor Nakauchi’s presentation with excitement, applauding the possibility of “personalized kidneys."