Tissues such as this one could also be used to test the effects of new drugs, circumventing disasters such as the TGN-1412 trial. In that test, now known in the press as the "elephant man drug trial," the bodies of six volunteers flared up to dangerous levels after being administered an experimental drug, leaving at least one with terminal cancer. Having artificial tissue to test on could also mean fewer animal experiments, the researchers noted.
Within five years, grown liver tissue could repair livers damaged by injury, disease, alcohol abuse, and over-the-counter painkiller overdose, and entire livers could be quickly replaced roughly 15 years from now, the researchers said. In 2004, 72 people in the U.K. died while waiting for a suitable transplant donor, and there are currently 336 people on the liver transplant list there.
The miniature liver, approximately the size of a penny, was grown from stem cells. These blank cells are found in the blood from the umbilical cord and can be turned into specific types of tissue when removed from the umbilical cord minutes after a baby is born. Scientists then place the cells in a NASA-developed "bioreactor," which simulates weightlessness. Without the effects of gravity, the cells multiply more quickly, after which various hormones and chemicals are added to cause the stems cells to transform into liver tissue.
Stem cell research, especially embryonic stem cell research, has caused a lot of controversy since it usually requires the destruction of a human embryo, but this technique is considered more ethically acceptable as no such destruction is required.
The Newcastle researchers postulated a worldwide donor register for liver dialysis and transplant could be formulated if the umbilical blood of millions of babies is preserved each year, using a computer registry to track blood compatibility. More than 11,000 British parents already freeze their children's umbilical blood, which is used to treat leukemia.
"One hundred million children are born around the world every year -- that is 100 million different tissue types," said Colin McGuckin, professor of regenerative medicine at Newcastle University. "With that number of children being born every year, we should be able to find a tissue for me and you and every other person who doesn't have stem cells banked."
Liver experts such as professor Nagy Habib of London's Hammersmith Hospital have welcomed the breakthrough, but warn that more research is needed before the results can be put into practice.
"The stem cell is going to change the way we deliver treatment," he said. "However, it won't happen tomorrow."
Mike Adams, a consumer health advocate and author of the free health guides at Truth Publishing, had an even stronger warning.
"The growing of artificial organs in a laboratory may seem like an amazing medical breakthrough, but the issue is far more complex than most people realize. We should observe this with extreme caution and skepticism," he said. "While scientists are working feverishly to figure out how to grow a replacement organ in the lab, for example, no one is teaching patients how to take care of the liver they already have.
"The emphasis in medicine is on expensive, heroic treatments such as transplants, yet conventional medicine utterly ignores what patients need most: prevention of disease and the support of the vital organs they were born with," Adams said.