Science takes giant leap
2005-05-20 08:03
Washington - A team of South Korean scientists has developed the first lines of patient-specific embryonic stem cells, designed to give a precise DNA match, according to a study released on Thursday in the United States.
The research marks major strides in work aimed at making it possible one day to transplant healthy cells into humans to replace cells ravaged by illnesses such as Parkinson's and diabetes, said the researchers, whose work was published in the May 20 issue of Science.
Co-author on the study, Dr Gerald Schatten of the University of Pittsburgh School of Medicine called the development "a major advance in the science of using stem cells to repair damage caused by human disease and injury".
"What the study shows is that stem cells can be made that are specific to patients regardless of age or sex and that these cells are identical genetic matches to the donor," Schatten said.
The advance came from the same Korean researchers who produced the first line of stem cells from a human embryo at 5-10 days - at that point called a blastocyst - which had been cloned. That research was announced in March 2004.
Thursday's announcement of the new research came one week before a debate starts in the US House of Representatives on federal funding of stem cell research on days-old embryos held in the freezers of fertility clinics donated by couples who no longer need them.
Not for reproductive purposes
In the new Korean research, 11 new lines of embryonic stem cells were created by transferring genetic material from a non-reproductive cell of a patient into a donated egg, or oocyte, from which the nucleus had been removed. The method is called somatic cell nuclear transfer, or SNCT, researchers said.
Then oocytes with the genetic material of the patient were developed to the blastocyst stage, an early phase of embryo growth.
"Stem cells were then derived from the inner cell mass of the blastocyst," the Science authors Woo Suk Hwang of Seoul National University, and colleagues, reported.
Eighteen women, including 10 under age 30, donated the eggs, and 11 people, both male and female from ages two to 56 years, donated skin cells to provide the non-reproductive tissue.
Some 185 such eggs had their nucleus exchanged for genetic material from sufferers of juvenile diabetes, spinal chord injury and congenital hypogamma-globulinemia - an illness that can give increased risk of infections.
The Korean researchers said it took an average 17 eggs to make each stem cell line. They cautioned that such cloning for reproductive purposes would be dangerous and should not be attempted.
"The small number of oocytes needed to derive these stem cell lines should allay the concerns expressed by some critics that stem cell research would somehow lead to mass exploitation of women for their eggs," said Dr Robert Schenken, president of the American Society for Reproductive Medicine.