A leading University of Pittsburgh researcher on embryonic stem cells said yesterday that he will disengage from a recently launched collaboration with a team of world-renowned South Korean scientists because he is convinced that the lead Korean researcher had engaged in ethical breaches and lied to him about them.
The Pitt scientist, Gerald P. Schatten, has for more than a year been the prime American stem cell scientist working with the South Korean researcher, Woo Suk Hwang of Seoul National University. Hwang was featured prominently in news reports in 2004 when he and his co-workers became the first to grow human embryonic stem cells from cloned human embryos. Since then, he has become something of a national hero and a global scientific celebrity.
Human embryonic stem cells, which have the capacity to become every kind of human tissue and are highly coveted for their potential to treat a wide variety of diseases, had previously been harvested only from conventional human embryos created through the union of sperm and eggs.
By deriving stem cells from cloned embryos, Hwang offered the first proof that a theorized approach to stem cell medicine -- "therapeutic cloning," or the creation of stem cells genetically matched to any patient who needed them -- was achievable.
Embryo cloning requires human eggs, which are typically donated by women in a process that requires a month-long series of hormone injections followed by a minor but not risk-free surgical procedure. Because of the modest but real health risks involved, researchers who perform the procedure are required to get informed consent from donors and fulfill other ethics requirements.
For many months after Hwang's 2004 publication, rumors had spread in scientific circles that the eggs Hwang used to achieve that landmark result had been taken from a junior scientist in his lab. That situation, if true, would be in violation of widely held ethics principles that preclude people in positions of authority from accepting egg donations from underlings. The rules are meant to prevent subtle -- or not-so-subtle -- acts of coercion.
Questions have also circulated as to whether the woman received illegal payments for her role.
Schatten said that Hwang had repeatedly denied the rumor and that he had believed Hwang until yesterday. "I now have information that leads me to believe he had misled me," Schatten said. "My trust has been shaken. I am sick at heart. I am not going to be able to collaborate with Woo Suk."
Just last month, at a high-level ceremony in Seoul attended by the South Korean president, Schatten and Hwang had announced a major not-for-profit collaboration that was to involve the creation of at least two major human embryo cloning labs in the United States and Britain. The plan was to have Korean scientists churn out as many as 100 specialized stem cell colonies each year for distribution to scientists for disease research.
Schatten said the University of Pittsburgh will release a statement today announcing its decision to pull out of that still nascent arrangement. Schatten said he will also announce his discovery of certain technical mistakes in a scientific paper he and Hwang had published together this year, though he added that he believes those errors were unintentional and did not represent evidence of scientific misconduct. He emphasized that the science behind the 2004 paper documenting the derivation of stem cells from cloned human embryos remains, to his knowledge, reliable.
The impact of yesterday's revelations could be far-reaching, Schatten and others acknowledged. Hundreds of scientists have visited Hwang's Seoul laboratories in the past two years, and many have initiated collaborations with him. The field has also been under scrutiny because of ethical concerns about the creation and destruction of cloned human embryos.
"The National Academy of Sciences guidelines for stem cell research prohibits payment to egg donors, and scientists in the U.S. have embraced those principles," said George Daley, a researcher at the Harvard Stem Cell Institute and at Children's Hospital Boston, who is scheduled to visit Hwang in Seoul later this month to look into setting up a collaboration. "There is a right way and a wrong way, and we must be sure to perform this vitally important medical research the right way."
Hwang could not be reached for comment last night.