More MS news articles for Dec 2001

Chinese pursue advances in cloning

Wednesday, December 26, 2001
By Michael Dorgan

GUANGZHOU, China - Those feeling squeamish about cloning will not find much comfort in the laboratory of Chen Xigu.

Here in the Experimental Animal Center of Sun Yat-sen University, where the walls are adorned with photos of genetically engineered rats, human chromosomes are being implanted in rabbit egg cells to create hybrid embryos.

The aim is not to make babies as cute as bunnies. Rather, director Chen and his staff have joined the global quest to use cloning to develop cures for such illnesses as diabetes and Parkinson's disease.

Chen says that so far, he has been able to grow the hybrid embryos only to the stage at which they remain a cluster of undifferentiated cells. He acknowledges that he is far from his goal of extracting stem cells from the embryos and turning the cells into treatments.

Cloning is an extremely complicated venture, with a high rate of scientific failure; in human cloning, no American scientist has been able to grow an embryo of more than six cells.

China does not have the same breadth and depth of research as the United States and other Western countries. Still, it has many scientists like Chen, who regard cloning as an important new frontier.

"If this research is successful, it will bring a revolution to medicine," Chen said excitedly during an interview in his spacious office.

He and others say cloning is an area of research in which Chinese scientists can afford to compete.

"As long as we have the idea and the skill to do it, we can do the research," Chen said.

But some caution that the aggressive pursuit of cloning breakthroughs in a nation with a weak regulatory environment and rampant corruption could lead to troubling ethical and social issues.

"It could get out of control," warned Gan Shaoping, an associate professor of ethics at the Chinese Academy of Social Sciences, a government-sponsored think tank.

So far, however, there does not seem to be much concern or debate, at least publicly.

After the Massachusetts-based Advanced Cell Technology announced late last month that it had cloned a human embryo that grew to six cells before dying, the Chinese government quickly reiterated its opposition to human cloning for reproduction. But it has not signaled any intention of imposing strict guidelines on cloning research aimed at creating new treatments for injuries or diseases.

The U.S. House of Representatives last summer passed a bill banning human cloning for both reproductive and therapeutic purposes, and the Senate is expected to debate similar legislation in the near future.

President Bush took up the issue in August in a prime-time address. His specific concern was the use of so-called stem cells from human embryos.

Stem cells are unspecialized cells that can renew themselves indefinitely and, under the right conditions, evolve into more than 200 types of specialized cells that make up organs, muscle and blood. Stem cells can be found in some adult organs, but the ones regarded as having the greatest potential for therapeutic purposes are found in embryos.

The core ethical issue for many is that the extraction of the cells destroys the embryo, regarded by some as a human being even at the earliest stages of development.

"Embryonic stem-cell research offers both great promise and great peril," Bush said in his speech. "So I have decided we must proceed with great care."

His solution was to allow federal funding for research only if the stem cells come from existing lines, or colonies, where "the life-and-death decision has already been made."

In China, no such restriction is contemplated, according to Yanguan Wang, an ethicist who is helping to draft new research guidelines from the Ministry of Health. She said the consensus among those drafting the guidelines was that there was no moral or ethical problem in destroying embryos that were less than 14 days old because the embryos were then simply clusters of cells devoid of human qualities or traits.

Wang said the Ministry of Health may decide not to fund projects that combine human genes and animal eggs - but that may not discourage the country's leading researchers.

One of Chen's ambitions is to grow human organs in animals for use in transplants.

"If we make something with a pig's head and a human body, that is not acceptable," he said. "But growing human organs inside a pig probably would be."

Li Lingsong, director of a research center at Peking University, announced earlier this year that his group already had cloned an elementary glandular structure that can secrete chemicals helpful in treating diabetes and Parkinson's disease. He said that he hoped to produce more advanced human organs within five years and that he was experimenting with techniques to introduce human cells into animal embryos to produce human organs for use in transplants.

But renowned cloning experts Rudolf Jaenisch at the Massachusetts Institute of Technology and Ryuzo Yanagimachi, the University of Hawaii reproductive biology professor who cloned the first mouse in 1997 , both dismissed the idea of growing human organs in animals.

"No, no, no," Yanagimachi said. The human cells "would be rejected. . . . Growing a human organ in other animals, I think it cannot be done. No way. I think they're just dreaming."

© 2001