From: Doug Skrecky (oberon@vcn.bc.ca)
Date: Fri Apr 28 2000 - 07:43:04 MDT
CryoNet - Fri 28 Apr 2000
Message #13652
From: Jan Coetzee
Report: Cloning Produces Unnaturally Young Cattle
By Maggie Fox, Health and Science Correspondent
WASHINGTON (Reuters) - Scientists who cloned six cows said on Thursday
the animals show
signs of being even younger than their chronological ages, and said this
could mean cloning
technology offers a true fountain of youth.
The cloning process seemed to have literally turned back the aging clock
in the cells of the six
heifers.
The researchers said it might be possible to use cloning to create
organs that are nearly immortal
for use in transplants, or tissue lines to treat diseases of aging such
as Alzheimer's, arthritis and
heart disease.
``Not only were we able to clone calves ... but these animals appear to
have cells younger than
their chronological age,'' Robert Lanza of Advanced Cell Technology,
Inc., who led the study,
said in a telephone interview.
Clock Gets Reset
``What we showed in this paper is this clock gets reset. It gets wound
back up,'' said Dr. Michael
West, president and chief executive officer of the Worcester,
Massachusetts-based company. ``It
remains to be determined whether this would extend the life of the
animal.''
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 that Lanza's 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, which included researchers at the Lakenau Institute
in Wynnewood, Pa., 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.
``Totally Cool''
``It's kind of abracadabra and through processes we don't understand,
they get reverted. It's totally
cool.''
The medical implications are profound, West said.
``It's the first day in a new era in treating age-related disease,''
West said.
``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.
Lanza said his team does not quite understand how the heifers became
``younger''. But he said
genes whose activity usually dies down as a cell ages were especially
active.
``These results suggest the animals are younger than their biological
age,'' Lanza said.
``When other cows the same age start to grow old and frail, their cells
should be able to divide
the same as a newborn calf's. They should be able to repair damage due
to disease and aging and
should live longer, healthier lives.
Only time will tell. Cows allowed to lead natural lives live to be 24
and older.
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