2 November 1998
Doctors regenerate human brain cells
By Maggie Fox, Health and Science Correspondent
WASHINGTON (Reuters) - Doctors said Monday they had shown,
for the first time, that human brain cells do divide and grow --
something that opens great possibilities for treating brain
damage caused by accidents and disease.
And California doctors said they were preparing to start an
experiment in which they will try to regenerate brain cells
outside the brain and re-inject them into patients with diseases
ranging from Alzheimer's to Parkinson's, as well as those with
spinal cord injuries.
Scientists say a series of recent experiments show the human
brain is not as immutable as previously believed -- and also
show that interesting breakthroughs in which paralyzed or
brain-damaged rats and mice have been made to walk again may
extend to humans.
``We knew this could happen in rats. It hadn't been proven
in humans. (Now) there's nothing biologically significant that
should keep us from going into humans and doing the same
thing,'' Evan Snyder of Harvard Medical School, who last week
reported a new technique for growing human brain cells and
getting them to function in rat brains, said in a telephone
interview.
Conventional wisdom has held that the human brain is special
-- that the neurons and other cells do not grow and divide like
other cells and that this is why brain damage is so hard to
correct.
But the brain cells of rats and other animals do grow, and
can be regenerated. Even human brain cells can be induced to
regenerate in a laboratory dish.
Fred Gage at the Salk Institute for Biological Studies
in La Jolla, California and colleagues were looking for evidence
that human brain cells grow, naturally, in the brain.
They looked at the brains of terminal cancer patients who
had been treated with a chemical, bromodeoxyuridine, that is
sometimes used to mark rapidly dividing cancer cells.
Working with colleagues at the Sahlgrenska University
Hospital in Sweden, they found that the chemical had been taken
up by the DNA in the dentate gyrus region of the hippocampus,
which is involved in learning and memory.
This, they reported in the journal Nature Medicine,
indicated that cells in this region had undergone replication
and the synthesis of new DNA.
``Our study demonstrates that cell genesis occurs in human
brains and that the human brain retains the potential for
self-renewal throughout life,'' they wrote.
``(The experiment) forces a new look at plasticity in an
organ previously considered an anatomical fait accompli at
birth,'' Nature Medicine said in a commentary.
A team at the Cedars-Sinai Medical Center in Los Angeles
hopes to use the ideas to help brain-damaged patients. They
announced a plan to take damaged brain cells from patients,
regenerate them in the lab, and then put them back in the brain.
``Right now we will use cell harvesting and implantation to
treat Parkinson's disease,'' Dr. Michael Levesque, the
neurosurgeon who will do the transplants, said in a statement.
Parkinson's is marked by the death of brain cells that
produce chemicals key to movement. Victims start out with
shaking that can progress to paralysis and death. There is no
cure.
``Treating stroke and spinal cord injuries with regenerated
cells is infinitely more complex,'' Levesque added.
``We have to identify, grow and reintroduce a complex
mixture of cells to restore a damaged circuitry. We're working
on a human protocol for spinal cord injury now and hope to start
treating patients with regenerated cells within the next six
months.''
^REUTERS@
--
Judith Richards, London, Ontario, Canada
<[log in to unmask]>
^^^
\ /
\ | / Today’s Research
\\ | // ...Tomorrow’s Cure
\ | /
\|/
```````
