Evidence that adult stem cells will not work for all types of cells.

[Guest guest]

Hi all,

Remember Bush and Brownback saying adult stem cells could be used?

http://story.news.yahoo.com/news?tmpl=story&u=/nm/20020313/sc_nm/science_stemcel\

ls_dc_1016058479

Researchers Cast Doubt on Adult Stem Cell Use

Wed Mar 13, 5:27 PM ET

By Reaney

LONDON (Reuters) - Adult stem cells may not be

able to change into

different types of cells and may have fooled

scientists by spontaneously

fusing with existing cells instead of creating

new ones, two teams of

scientists said on Wednesday.

Their findings could challenge the feasibility

of using adult stem cells to

provide treatments for a range of diseases and

cast doubts on studies

showing adult stem cells can develop into a

variety of tissues.

In two studies published online by the science

journal Nature,

researchers in Scotland and the United States

showed that adult stem

cells from bone marrow and the brain that were

grown along with

embryonic stem cells in the laboratory fused

spontaneously and created

hybrid cells.

" This suggests a need for caution with regard to

the therapeutic use of

adult tissue stem cells, " said Professor Austin

of the University of

Edinburgh who conducted one of the studies.

" If they only make other tissues by fusing with

existing cells rather than

producing new cells, their utility for tissue

repair and regenerative

medicine will be greatly restricted, " he added.

VIABLE ALTERNATIVE

The findings will add to the political and

ethical controversy surrounding

stem cell research.

Religious and anti-abortion groups oppose using

embryonic stem cells,

which are pluripotent or have the ability to

transform themselves into

virtually any other type of cell in the body,

because it involves the

destruction of human embryos.

Adult stem cells were considered a viable

alternative.

and his colleagues tagged brain cells from

mice with a green

fluorescent protein and combined them with

embryonic stem cells

without a marker.

After growing the two cell types in culture, the

scientists recovered cells

with the marker which showed characteristics of

embryonic stem cells

-- the ability to differentiate into many cells

types.

But when they analyzed the cells further they

discovered they were

fused cells that had genetic material from both

cell types and twice the

number of normal chromosomes.

Naohiro Terada a cell biologist at the

University of Florida in

Gainesville and his colleagues had similar

results when they mixed bone

marrow and embryonic stem cells in culture.

He said the findings could be particularly

significant following scientific

reports of transplanted bone marrow cells

turning into different cell

types such as nerve and muscle.

Terada suggests fused cells could have been

mistaken for the

differentiated adult stem cells.

" We need to look more closer before concluding

that adult stem cells

have real pluripotency or not, " Terada said in

an interview.

Last month Britain approved the cloning of human

embryos for

research and set up the world's first embryo

cell bank. In the United

States federally funded research on stem cell is

restricted to existing

stem cells lines.

" While there is justifiably a great deal of

interest in the broader

applicability of adult stem cells, our findings

illustrate that we are

currently very ignorant of their biology, "

said.