South Korea makes strides in human cloning
(Agencies)
Updated: 2005-05-20 18:44

SEOUL - South Korean scientists blazed a trail in stem cell research that matches the country's global leadership in high tech sectors and promises to bring life-saving benefits to sufferers of incurable diseases.

A team of experts led by Seoul National University professor Woo Suk Hwang said they produced stem cells by cloning human embryos using human eggs donated from volunteers and skin cells from patients.

The research marked a step forward in efforts to fight difficult diseases by cloning "therapeutic" stem cells and transplanting them into humans to replace cells ravaged by illnesses such as Parkinson's and diabetes.

In the study published by the journal Science, the group said there would be little risk of rejection by patients' immune systems because any potential therapy using this process would use cloned cells that share their own DNA makeup.

"This process opens the possibility of rejection-free stem cell treatment of many incurable or difficult diseases and injuries," Hwang told journalists.

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.

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.

Eighteen women, including 10 under the age of 30, donated the eggs, and 11 people, both male and female between two to 56 years old, donated skin cells to provide the non-reproductive tissue transferred to the denucleized egg to form the blastocyst.

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 researchers said it took an average 17 eggs to make each stem cell line.

Hwang and his colleagues made international headlines in February 2004 when they announced the first-ever cloning of human embryos, from which they extracted embryonic stem cells. At that time, body cells and an egg obtained from one and the same woman were used for the cloning.

The team said such cloning for reproductive purposes would be dangerous and should not be attempted.

Hwang also cautioned it would take a long time before this process could be applied to treatment purposes, noting technology to control the direction of the growth of stem cells remains unavailable.

"We need technology to control the growth of stem cells into specific cells or tissues that may replace damaged ones," Hwang said.

Han Hoon, a leading expert in umbilical cord blood stem cells, raised questions about Hwang's claim that those embryo stem cells were free of rejections.

"Rejections could occur because of the eggs used in the cloning," he said, adding any embryonic stem cells could also develop into cancer cells in a receiver's body.

Experts here said South Korea was able to catch up fast with other advanced countries and is now a step ahead of them in embryonic stem cell research thanks to the government's flexible policy in biological engineering.

"In contrast to the United States where the extraction of human ova is strictly controlled, it is rather easy to obtain them in this country if you have written consent from a donor," Han said.

Park Se-Pill, head of the private Maria Infertility Hospital Medical Institute, said South Korea had a fertile ground for embryo stem cell research thanks to its well-developed infertility industry.

"South Korea has highly advanced assisted reproduction technology as many Korean parents do not hesitate to spend fortunes in order to have their own babies instead of adopting other's kids," Park said.

Diligent researchers, government's financial support and legal backing for stem cell research also contributed to the achievement, he said.

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