In an attempt to circumvent the ethical issues surrounding the use of human embryos in medical research, scientists have come up with a method of deriving viable stem cells without harming the embryos.
They did so by extracting a single cell from the embryo -- as in vitro fertilization clinics do when they test for genetic defects -- and introducing a common molecule called laminin to keep it in a stem cell, or pluripotent, state.
Subsequent development of the embryo was unaffected by the biopsy, according to the study published Thursday by the journal Cell Stem Cell.
The new technique holds the promise of dramatically speeding up clinical applications of stem cell therapies for a wide range of debilitating diseases and illnesses.
Stem cells are considered a potential magic bullet because they can be transformed into any cell in the body and potentially used to help replace damaged or diseased cells, tissues and organs.
However, embryonic stem cell research is highly controversial because, until now, viable embryos were destroyed in the process of extracting the stem cells.
Two groups of scientists recently bypassed this problem by transforming human skin cells into stem cells.
Skin cells will likely become the most common source of stem cells, said Australian researcher Alan Trounson, who heads the world's biggest stem cell research project at the California Institute for Regenerative Medicine.
But skin cells are still far from ready for clinical use because the transformation process introduces potentially deadly genetic alterations and viruses.
Which means embryonic stem cells, which do not carry the same risk of mutation, are currently the only option for therapeutic applications, Trounson said.
"There will (also) be a lot of people interested in the embryonic stem cells because they are the gold standard," he told AFP, explaining that the stem cells derived from skin have not been fully investigated.
Stem cell pioneer Robert Lanza hopes the technique he helped develop to preserve the embryo will spur US regulators to allow funding for research on new embryonic stem cell lines.
Progress in the promising field has been stifled by restrictions on access to federal funds in the United States and outright bans on embryonic research in other countries due to ethical concerns.
"Within the next few months we could make as many of these cells as we like," said Lanza, chief scientific officer at Advanced Cell Technology.
"We really can't afford to hold this field up any more."
Lanza also cautioned against relying upon the stem cells derived from skin.
"I've been in this field for too long and been fooled too many times. When you have something you move ahead," Lanza said in a telephone interview.
"These are useable. They are not genetically modified. They're here."
But a leading opponent of embryonic stem cell research said Lanza's method -- while "morally laudable" in principal -- "still fails to deliver any kind of ethical solution."
"Any procedure that places at risk the health and life of a human embryo for purposes that do not directly benefit the embryo is morally unacceptable," said Reverend Tadeusz Pacholczyk, director of education at the National Catholic Bioethics Center.