"What you have been told is nothing more than a myth," he said, "intended to ensure funding for researchers, at the expense of false hopes for the seriously ill. So let's get to the truth."
Stem cells, he explained, are cells that have the ability to turn themselves into other kinds of cells. There are two kinds of stem cells. Adult stem cells are found throughout the body. They are found in muscle, brain, and liver tissue, and so on. Adult stem cells can generate new cells, but only of the tissue in which they are found. They are important because the human body replaces all its cells every seven years.
Research involving adult stem cells is for the most part not controversial. But there is another kind of stem cell, the embryonic stem cell, that is highly controversial. It is found in umbilical cord blood, or derived from young embryos. Embryonic stem cells are pluripotent, meaning they can develop into any kind of tissue. But the research is controversial because it involves the use of human embryos, which many people feel, for religious and other reasons, have the rights of human beings. This is an old debate not likely to be resolved soon.
SCIENTISTS SEE A BAN ON RESEARCH
The current American administration has said that embryonic stem cells can be taken from existing research lines, but not from new embryos. Scientists regard existing lines as inadequate, and thus view the ruling a de facto ban on research. That's why they are going to private centers to carry out their research, without federal grants.
But in the end, the real problem isn't simply a lack of stem cells. It's the fact that in order to produce therapeutic effects, scientists need each person to have his or her own pluripotent stem cells. This would allow us to regrow an organ, or to repair damage from injury or disease, or to undo paralysis. This represents the great dream. No one is able to perform these therapeutic miracles now. No one even has an inkling how it might be done. But it requires the cells.
Now, for newborns, you can collect umbilical cord blood and freeze it, and people are doing that with their newborns. But what about adults? Where will we get pluripotent stem cells?
That's the big question.
TOWARD THE THERAPEUTIC DREAM
All we adults have left is adult stem cells, which can make only one kind of tissue. But what if there were a way to convert adult stem cells back into embryonic stem cells? Such a procedure would enable every adult to have a ready source of his or her own embryonic stem cells. That would make the therapeutic dream possible.
Well, it turns out that youcan reverse adult stem cells, but only if you insert them into an egg. Something within the egg unwinds the differentiation and converts the adult stem cell back into an embryonic stem cell. This is good news, but it is vastly more difficult to do with human cells. And if the method could be made to work in human beings, it would require an enormous supply of human egg cells. That makes the procedure controversial again.
So scientists are looking for other ways to make adult cells pluripotent. It is a worldwide effort. A researcher in Shanghai has been injecting human stem cells into chicken eggs, with mixed results - while others cluck in disapproval. It's not clear now whether such procedures will work.
It's equally unclear whether the stem cell dream - transplants without rejection, spinal cord injuries repaired, and so on - will come true. Advocates have made dishonest claims, and media speculation has been fantastical for years. People with serious illnesses have been led to believe a cure is just around the corner. Sadly, this is not true. Working therapeutic approaches lie many years in the future, perhaps decades. Many thoughtful scientists have said, in private, that we won't know whether stem cell therapy will work until 2050. They point out that it took forty years from the time Watson and Crick decoded the gene until human gene therapy began.
A SCANDAL SHOCKS THE WORLD
It was in the context of feverish hope and hype that Korean biochemist Hwang Woo-Suk announced in 2004 that he had successfully created a human embryonic stem cell from an adult cell by somatic nuclear transfer - injection into a human egg. Hwang was a famous workaholic, spending eighteen hours a day, seven days a week, in the lab. Hwang's exciting report was published in March 2005 inScience magazine. Researchers from around the world flocked to Korea. Human stem cell treatment seemed suddenly on the verge of reality. Hwang was a hero in Korea, and appointed to head a new World Stem Cell Hub, financed by the Korean government.
But in November 2005, an American collaborator in Pittsburgh announced that he was ending his association with Hwang. And then one of Hwang's co-workers revealed that Hwang had obtained eggs illegally, from women who worked in his lab.
By December 2005, Seoul National University announced that Hwang's cell lines were a fabrication, as were his papers inScience. Science retracted the papers. Hwang now faces criminal charges. There the matter stands.
PERILS OF "MEDIA HYPE"
"What lessons can be drawn from this?" asked Professor McKeown. "First, in a media-saturated world, persistent hype lends unwarranted credulity to the wildest claims. For years the media have touted stem cell research as the coming miracle. So when somebody announced that the miracle had arrived, he was believed. Does that imply there is a danger in media hype? You bet. Because not only does it raise cruel hopes among the ill, it affects scientists, too. They start to believe the miracle is around the corner - even though they should know better.
"What can we do about media hype? It would stop in a week, if scientific institutions wanted that. They don't. They love the hype. They know it brings grants. So that won't change. Yale, Stanford, and Johns Hopkins promote hype just as much as Exxon or Ford. So do individual researchers at those institutions. And increasingly, researchers and universities are all commercially motivated, just like corporations. So whenever you hear a scientist claim that his statements have been exaggerated, or taken out of context, just ask him if he has written a letter of protest to the editor. Ninety-nine times out of a hundred, he hasn't.