Tissue Transplant Field Gaining Rapid Sophistication, Experts Say
by Joan Samuelson, President, Parkinson's Action Network
A February meeting of international experts in neural cell
transplantation reveals a field exploding in sophistication, with the
effectiveness of Parkinson's therapies increasing and leading the way for an
array of other disorders.
The 6th International Neural Transplantation Meeting in San Diego,
California consumed three intensive days of slide presentations, poster
sessions and informal discussion to share emerging strategies to repair the
brain. In addition to presenting the state of the art in cell grafting
technology, the scientists borrowed from the emerging arenas of neural growth
factors, new cell sources, and gene therapies to increase success with
transplants.
The boom in this field was apparent: More and more have named their
clinics "Neuroregeneration Labs," "Neural Transplant Clinics," or "Section
for Neuronal Survival" to reflect the future of this field. Scientists came
from all over the U.S. and several foreign countries including Japan, France,
Israel, Sweden and Germany. Several biotech houses were collaborators with
academic labs.
Highlights included:
TRANSPLANT TECHNIQUE. Now that transplants have shown they can survive
implantation, produce dopamine and thereby reduce Parkinson's symptoms,
scientists are concentrating on refinements of the technique to increase its
effectiveness.
They report that on average a transplant recipient is able to reduce
dopamine replacement medication (Sinemet) by 50% plus experiencing a 30%
decrease in Parkinson's symptoms. A few recipients worldwide are presently
off medication entirely and symptom-free. A major target for improving these
numbers is cell survival: since only 5-to-10% of the cells implanted
survive, even a modest increase could result in a significant symptomatic
improvement.
Strategies reported on include Refining The Tissue Preparation before
transplantation; the Exact Location of the tissue (the substantia nigra vs.
the striatum, or both) and the Exact Age of tissue implanted. Researchers
showed interest in other neurochemicals besides dopamine present in the
grafted tissue - serotonin or acetylcholine neurons, for example - which may
play a role in transplant survival.
ALTERNATIVE CELL SOURCES. Several alternatives to human fetal tissue
are in development. In addition to "xenografts" (tissue from non-human
sources such as pig cells), several reported on major progress in developing
"cell lines," by which a small quantity of tissue in the early stage known as
"stem cells" or "progenitor cells" can be engineered into replicating itself
into an infinite supply.
NEURAL GROWTH FACTOR AS a survival "booster." Many report results in
merging transplants with another Parkinson's-therapy field -- growth factor,
in particular "GDNF," which shows the capacity to revive dormant dopamine
cells -- to be combined with transplanted cells as an aid to cell survival.
Several presenters described experiments using "cocktail" combinations of
growth factors or other substances added to boost survival and output of
dopamine.
VIRUSES AS CONVEYORS OF THERAPEUTIC AIDS past the blood-brain barrier.
The growing understanding of use of viruses, stripped of their harmful
properties and used as carriers of growth-enhancing properties into the
brain, indicates they may be alternatives to surgery or a periodic "booster"
to maintain the capacity of dopamine cell implants.
APPLICATIONS BEYOND PARKINSON'S. Although the spotlight was on
Parkinson's-related therapies, researchers reported an array of experimental
applications of cell transplants, including to combat spinal cord injury,
blindness, Huntington's, intractable cancer pain, Alzheimer's, birth defects
and MS.
(For a thorough review of the meeting, look for a summary by Judy Rosner,
Executive Director of the United Parkinson Foundation, in the upcoming issue
of the UPF Newsletter. To receive a copy , call the UPF in Chicago at
312-733-1893.)
-----------------------------------------------
Parkinson's Action Network 800-850-4726
Headquarters:
818 College Ave., Suite C
Santa Rosa, CA 95404
phone 707-544-1994 fax 707-544-2363 email [log in to unmask]
Washington, D.C. office:
601 13th Street, NW., Suite 310
Washington, DC 20005
phone 202-628-2079 fax 202-628-2077
Brad Udall, Chair
Joan I. Samuelson, President
John L. Dodge, Treasurer
Bonnie K. Mioduchoski, Administrator
Michael Claeys, Community Coordinator
The Action Reporter is a free publication of the Parkinson's Action Network,
a non-profit charitable foundation for a cure for Parkinson's. Use of this
material in other publication is welcomed. We ask that the Network be
identified as the source of the material, and notified how, when and where
the material is used. Simply call 800-850-4726
