Stem cells show potential for eye repair

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Stem cells show potential for eye repair

Could be used to treat blindness, company says

http://www.msnbc.msn.com/id/6089652/

Corporate researchers working outside controversial federal restraints

said on Thursday they had engineered human stem cells that they

believe could be used to repair eyes.

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The team at Advanced Cell Technology in Massachusetts worked with stem

cells taken from human embryos made by a team at Harvard University,

and coaxed them to form retinal cells.

" This is the first derivation of retinal cells from human embryonic

stem cells, " said Dr. Lanza, Advanced Cell Technology's

scientific director.

" We believe these new retinal cells could be used to treat blindness

and may, in fact, be the one of the very first applications of

embryonic stem-cell technology. "

The cells clustered into small globes on their own.

" They looked like little eyeballs, " Lanza said in a telephone

interview. " These things seem to be trying to assemble into primitive

eyes. "

The only cells they could clearly define were retinal cells, but Lanza

said some also resembled the cells that make rods and cones -- the

light receptors of the eyes.

The retina is the coating on the back of the eye that receives a

visual image and transmits it to the optic nerve.

" Therefore, we think that millions of patients with retinal

degeneration might conceivably benefit from these cells in the

future, " Lanza said.

Stem cells are master cells that can give rise to various cells and

tissues. Unlike fully mature cells, they have a variety of potential

futures.

Those taken from very early embryos, just a few days old, seem to have

the most potential to become various cells. Not only can they form any

tissue or cell type, but they seem to have the ability to live for a

very long time, as well.

Controversial science

Embryonic stem cells can come from two sources -- embryos left over

from attempts at in vitro fertilization, also known as test-tube baby

pregnancies, and those made using cloning technology.

Some groups oppose their use because they feel any medical research on

a human embryo is unethical. Some only oppose using cloned embryos,

while the majority of scientific researchers in the field, as well as

Congress, say it is all right to use leftover embryos that would

otherwise be discarded.

But U.S. President W. Bush restricted the use of federal

funding to work on stem-cell batches that had already been created

before August 9, 2001. Scientists complain these existing batches, or

lines, are contaminated with animal cells used to nurture them and

that there are not enough.

Stem cell biologist Irina Klimanskaya, who worked both at ACT and with

stem-cell researcher Dr. Melton of Harvard, made several

batches of stem cells using purely private funds.

The new batches work better than those made before 2001, said Lanza,

because the technology used to make them has improved. They are not

contaminated with animal viruses, and could safely be transferred

directly into people, he added.

" In fact, we would not have made this discovery if our research had

been limited to the stem-cell lines approved by President Bush, " Lanza

said.

" The question is how many other important scientific or medical

breakthroughs have not occurred because of the current stem-cell

policy. This is what we've been trying to tell the president for

years. "

Lanza said the report, published in the journal Cloning and Stem

Cells, also illustrate the need to use cloning technology. In some

experiments eye-cell transplants have been rejected by the patient's

immune system.

But cells made using a person's own genetic material --through cloning

technology -- would be a perfect match.

" People don't realize there is only a handful of people working with

embryonic stem cells, " he said. " If there's no money, there is no

research that can happen. "