Medical Tribune
Researchers Grow New Human Brain Cells
From Stem Cells
February 29, 2000
For the first time, researchers have isolated stem cells from human
brains and have
demonstrated that these cells can develop into new mature brain cells.
Harnessing this natural restorative property of the brain may one day
help scientists to
replace damaged brain tissue that causes dysfunction in such conditions
as Alzheimer's
disease, PARKINSON'S disease and stroke.
According to the authors of the report, the potential of new therapies
using this
knowledge ``may be profound.''
Dr. Steven Goldman, professor of neurology and neuroscience at Cornell
University
Medical College in New York, and his colleagues studied the brains of
eight men, ages
5 to 63. These patients were undergoing brain surgery to treat such
conditions as
epilepsy and aneurysms.
During the surgery, the patients had very small sections of their
brains removed. These
sections came from an area of the brain called the dentate gyrus. This
area is located
within the hippocampus, a C-shaped structure in the middle of the
brain, which is
involved in learning and memory. Within these sections existed both
mature neurons
and progenitor cells that had the researchers believed would grow into
new brain cells.
A number of recent studies have indicated that, contrary to previously
accepted dogma,
the mature brain does grow new neurons constantly, and many of these
new neurons
sprout from progenitor cells in the hippocampus.
The researchers then placed all the cells in a culture that would allow
the cells to live
and grow. They labeled the cells with chemicals that incorporated
themselves into only
new cells. The investigators found that new cells did proliferate and,
over the course of
a month, the number of cells increased by 500 percent.
The report appears in the March 2000 edition of the journal Nature
Medicine.
They then tested the neurons, to see if they shared the chemical and
physiological
properties of normal neurons. They found that the brain cells responded
and acted just
as regular neurons do.
Goldman, a senior attending neurologist at New York Presbyterian
Hospital, said that
in the future, physicians may be able to stimulate new neuron growth
either chemically
or by extracting progenitor cells from one area of the brain and
reintroducing them into
another. He explained that transplantation may be more useful in
stroke, where the
cause of the damage a blood clot or ruptured blood vessel can be
eliminated.
Physicians could remove progenitor cells from the opposite side of the
brain where the
stoke occurred. They could then grow cells in culture and reintroduce
them into the
area where the stroke occurred.
In a disease like Alzheimer's, where the area of damage the hippocampus
resides
deeper in the brain and the cause of the disease would not necessarily
be removed,
chemically stimulating stem cells to produce more neurons may be more
advantageous
than surgery. However, he suggested that decisions about which patients
would benefit
from surgery would need to be made on a case-by-case basis.
According to an editorial that accompanied the research, transplanting
progenitor cells
from one area of a person's brain to another reduces the risk of
transplant rejection that
can occur during fetal cell transplants.
Dr. Jack Antel, from the Montreal Neurological Institute at McGill
University, was the
lead author of the editorial.
However, the editorial authors noted that transplanting cells into an
area damaged by a
disease like Alzheimer's might prove to be an ineffective therapy.
``After being
re-implanted, will the progenitor cells also be targets of the primary
disease process?''
they wondered.
Nature Medicine (2000;6:250-251,271-277)
Copyright 2000 Medical PressCorps News Service.
--
Judith Richards, London, Ontario, Canada
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