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April 29, 2000: CAN CLONING RETARD AGING?

(Adapted from wire service reports April 27)

Six cloned cows show signs of being younger than their chronological ages. Their cloning method, developed at Advanced Cell Technology Inc. (ACT), appears to have reversed the aging process of cells, opening the door to creating organs that are nearly immortal for use in transplants, scientists said.

The cloning technique may also allow scientists to create tissue lines to treat disorders ranging from Parkinson's and Alzheimer's to diabetes and heart disease, said researchers at ACT, which performed the research. Cloning could also supply a crop of youthful cells to increase the breeding years of farm animals.

Nevertheless, the researchers admit that they still don't know exactly how cloning helps cells shrug off the signs of aging, or whether this actually translates into a longer lifespan for the animals themselves.

"We've shown that the clock gets reset," said Dr. Michael West, president and chief executive officer of the Worcester, Mass.-based ACT. But, "It remains to be determined whether this would extend the life of the animal."

Plus, any human work could be mired in an ethical debate, as it would technically involve cloning the patient.

But there's no denying the scientific value of the work, said Leonard Hayflick, professor at the University of California, San Francisco, who is considered the discoverer of the aging process in human cells. "This study represents a milestone in our efforts to understand how mammalian longevity is determined." Hayflick was not involved in the research.

The findings, published in the journal Science, are surprising because the most famous cloned animal, Dolly the sheep, appears to be older than her chronological age.

Dolly, whose birth was announced in 1997, was the first mammal to be cloned using an adult cell. Her makers at the Roslin Institute in Edinburgh, whose technology now belongs to Geron Bio-Med, found signs that her cells, when she was born, were the same age as the cells of the 6-year-old ewe from which she was cloned.

They calculate this by looking at the telomeres, which are little caps on the ends of the chromosomes that carry the genetic blueprint inside cells. Each time a cell divides, the telomeres become a little worn. When they are frayed beyond repair, the cell dies. This stage is known as senescence.

Dolly had old telomeres. But the six heifers, cloned from cells taken from a 45-day-old fetus, have exceptionally young telomeres.

What is even more surprising is that the cells the ACT team cloned were not fresh and new. They had been grown and allowed to divide over and over again in the laboratory until they were senescent.

The team, led by Dr. Robert P. Lanza, vice president of medical and scientific development at ACT and which included researchers at the Lakenau Institute in Wynnewood, Pennsylvania and Thomas Jefferson University in Philadelphia, fused the cells into cow eggs using a slightly different cloning process than that used to make Dolly.

"The egg cells acts like a little time machine and can take it back, as far as we can tell, to the beginning of life," West said. And this difference in cloning techniques may help explain why the results are so different, he said.

Differences in the original donor cells used -mammary cells for Dolly - and fibroblast, or connective tissue, cells for the cows - may also play a role, he said.

The medical implications are profound, West said. "It's the first day in a new era in treating age-related disease. We could take one young cell from a patient and make hundreds or thousands of young cells and put them back in the patient and give them back a young immune system or give them back young cartilage in their knees," he added.

"If you had a damaged heart, we could take a few cells from you and grow up new heart cells and these would be your own cells so you wouldn't reject them," added Lanza.

Of course, this would involve technically cloning the patient - something called therapeutic cloning - and there would be opposition to allowing it. But Lanza said the cells created would never be slated for development as a human embryo.

"Once people understand the science here, the more they hear about it, the more likely they are going to say this is a good thing," he said.

His team is continuing to work with cloned cells. In 1998 they created clones using human cell nuclei and cow cells, which did not develop into embryos but into a dishful of cells.

Online links to new stories on this subject are available at www.msnbc.com/news/400436.asp and www.lef.org/featured-articles/apr2000_clon_01.html.