To find stem cells, scientists focus on fat

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To find stem cells, scientists focus on fat

Waist product may have medical value, scientists say

The Associated Press

Updated: 12:57 p.m. ET Oct. 4, 2004

http://www.msnbc.msn.com/id/6116024/

Dr. Ersek, a 66-year-old plastic surgeon, invited reporters to

his Texas operating room recently and, in front of their cameras,

proceeded to liposuction himself.

After numbing the skin near his navel, he slipped in a hollow tube

about a quarter-inch wide and moved it back and forth until it had

sucked out about half a pound of fat.

Ersek's office throws away tons of liposuctioned fat every year. But

he shipped his own to a California company for processing and

long-term storage of some of the cells from that fat.

Why did he do that? It turns out the type of cell being stored for

Ersek is medically promising. In fact, an international group of

scientists is meeting this week in Pittsburgh to discuss its

potential.

Medical value? In fat? The waist product most people want to get rid

of?

`We're trying to make fat do good.'

— Dr. J. Rubin

International Fat Applied Technology Society

It's true. As members of the fledgling International Fat Applied

Technology Society will discuss at their meeting, fat is a

little-discussed source of stem cells, those versatile biological

building blocks that can morph into a variety of tissues. Fat-derived

stem cells, researchers say, might someday provide replacement tissue

for treating such conditions as Parkinson's disease, heart attacks,

heart failure and bone defects.

" We're trying to make fat do good, " says IFATS president Dr. J.

Rubin, assistant professor of plastic and reconstructive surgery at

the University of Pittsburgh School of Medicine.

GUIDE Stem cell research

Harvesting stem cells

• Step One

• Step Two

• Step Three

• Step Four

Glossary

Embryonic stem cells used in research most often come from embryos

left over after in vitro fertilization procedures.

Step One: An egg is fertilized by a sperm in a lab dish.

Step Two: The fertilized egg begins to divide and develop into an

embryo. About five days later, the embryo becomes a blastocyst -- a

hollow ball of about 100 cells. The inner cells are the embryonic stem

cells.

Step Three: Stem cells are removed from the blastocyst and cultured in

the laboratory where they theoretically can multiply indefinitely.

Step Four: By adding and removing certain proteins, scientists can

coax the cells to develop into new heart, bone, nerve or other cells

to treat diseases.

Assisted reproductive technology: Fertility treatments that involve a

laboratory handling eggs or embryos, such as in vitro fertilization.

Blastocyst: A preimplantation embryo of 30 to 150 cells.

Differentiation: The process by which early unspecified cells acquire

the features of specific cells such as heart tissue, liver or muscle.

Embryo: The earliest stage of development from the single cell to

implantation in the uterus.

Embryonic stem cell: A cell from an embryo that has the potential to

become a wide variety of specialized cell types.

In vitro: Done outside the body.

In vivo: Done within the living body.

Tissue or cell culture: Growth of tissue in a laboratory dish for

experimental research.

Source: Associated Press, MSNBC research • Print this

An overlooked potential source

The fat-derived cells, which are being studied by relatively few labs,

aren't the ones that store fat. Instead, they're found in between

fat-storing cells. They're an example of so-called " adult " stem cells,

different from the controversial embryonic stem cells.

When stem cells are taken from an embryo, the embryo is destroyed.

That's abhorrent to people who consider an embryo to be developing

human life. President Bush has restricted federal money for research

into embryonic stem cells, a step that Democratic presidential nominee

Kerry has said he will reverse if elected.

Some who oppose research into embryonic stem cells champion the cause

of adult stem cells, which are found in bone marrow and elsewhere and

theoretically could be taken from the very people who will be treated

with them. In recent years, scientists have found evidence that adult

cells can turn into a wide variety of cell types.

While such studies have focused largely on cells from marrow, fat has

" certainly been overlooked as a potential source of stem cells, " says

Dr. Adam Katz, a plastic surgeon who studies the fat-derived cells at

the University of Virginia. Actually, it's probably the most practical

source, he said.

Related story

Stem cells show potential for eye repair

Why?

Fat is plentiful and researchers say it's easy to harvest — much

easier than marrow, for example. Just about everybody, even slender

people, carries enough to yield a good supply of cells for their own

treatment. Fat produces so many stem cells that there's no

time-consuming need to grow more of them in the lab. Giving up some

fat isn't likely to be medically dangerous. And after all, who'd

object?

" This is the only stem cell that people will pay you to take out of

them, " says Lee, chair of the neuroscience department at the

University of Virginia.

While Ersek's self-liposuction was meant to publicize the idea of

banking one's own fat-derived cells for future use, researchers say

doctors may one day remove fat right when the cells are needed.

To be sure, the research into fat-derived cells is still in very early

stages and many questions remain. Katz, in fact, says he's not even

convinced the cells deserve to be called stem cells, because he's not

sure they really do turn into other kinds of cells when transplanted

into the body. Nonetheless, he says they do show promise for being

used someday to treat disease.

Rubin says there's good evidence the fat-derived cells can morph into

bone, cartilage, skeletal muscle, blood vessel tissue and fat, at

least in the laboratory, with suggestive evidence they can also turn

into heart muscle and nerve cells.

Lee says people look at him askance when he talks about research into

fat-derived cells, but some studies point to a possible payoff.

—Last May, scientists reported that such cells could turn to bone and

heal defects in the skulls of mice.

—Korean scientists reported last year that when they put human

fat-derived cells in the brains of rats that had simulated strokes,

the animals showed some improvement.

—Lee has found the cells will migrate to damaged brain areas in rats

and turn into what looks like brain cells, though it's not clear yet

whether the cells hook up with neighbors to form working circuits.

—Dr. Kai Pinkernell, a cardiovascular researcher at Tulane University,

says he found an encouraging result in pigs that were given

experimental heart attacks. When he took fat-derived cells from the

pigs and put them into the hearts of the same donor animals, those

hearts began to work better.

In fact, they worked just as well as hearts that received stem cells

from marrow, the gold standard for this kind of experiment, he said.

Mighty morphing cells?

But how? The standard explanation would be that the cells, sensing

that the heart needed new muscle to replace tissue lost in the heart

attack, morphed into heart muscle. But Pinkernell said he can't prove

that. He also says he's more interested in the results than the

explanation.

Katz, the skeptic about whether such cells really change identities,

said they could be producing therapeutic effects in other ways. Maybe

they're alerting other stem cells that already live in the target

tissue or that show up from the marrow, he said. Or maybe they're

stimulating the growth of new blood vessels that speed up healing.

Dr. Marc Hedrick, president of Macropore Biosurgery Inc. of San Diego,

which hopes to harness such cells to treat heart attacks, said there's

good evidence the cells can become heart muscle cells. But they

probably also stimulate nearby cells to make new blood vessels,

heightening the therapeutic effect, he said.

" They're like orchestra leaders, we think, in terms of healing, "

Hedrick said. " They not only participate by playing an instrument, but

they also direct some of the other people in the orchestra. "

In any case, Rubin figures fat-derived cells might also someday

provide a way to grow replacement bone and cartilage to resurface

joints damaged by arthritis. They might even be used to make more fat,

for uses like breast reconstruction after surgery, he said.

Researchers say they need to learn much more about just what the cells

can do and how safe it would be to use them in treatment, especially

what the long-term risks might be. Attempts to test the cells in

humans have been scarce worldwide, but researchers said human studies

in the United States might start within five years.

Dr. Curt Civin, a stem cell expert at s Hopkins University in

Baltimore, called the fat-derived cells intriguing but said he had

some questions of his own: How do they compare with stem cells from

elsewhere in the body, like bone marrow? Do they really live in fat

deposits or are they just passing through via the bloodstream? Apart

from their abundant supply, do they have any unique abilities?

" When you really do the cost-benefits, do they come out, even if

they're not unique, as superior in some respects? " Civin asked. " The

jury is still out. "

Pinkernell, for one, is optimistic about finding a medical value in

fat.

" Not a lot of researchers in the world have realized this tissue might

be a potential source of these types of cells, " he said. " But I think

it's just a matter of time. "

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