January 30, 2001
Sonic may boost cancer, AIDS care
By MARY-JANE EGAN, Free Press Health Reporter
London, Canada -- Scientists have identified a molecule that fuels
production of human stem cells -- a discovery that could accelerate new
treatments for spinal-cord injury, cancers, Alzheimer's disease,
Parkinson's, diabetes and AIDS.
Called Sonic Hedgehog, the molecule was supposedly named several
years ago by a discoverer fond of the video game Sonic the Hedgehog.
The molecule -- cloned years ago from a fruit fly -- had never been
applied to human stem cells until the John P. Robarts Research Institute
team started work four years ago.
Their work, published today in the scientific journal Nature Immunology,
is the first time rare adult human stem cells have been mass produced
and triggered to form other tissues, such as brain neurons, muscle and
pancreatic islet cells, said lead author and Robarts researcher Mick
Bhatia.
"This really opens up this whole new door to cell- replacement therapies
and regenerative therapies," Bhatia said. "These are buzzwords that have
been thrown around by scientists but with very few people tackling the
real problem of taking these cells, making a lot of them, making them
into the tissue you want and then transplanting them into the patient."
Stem cells are master cells that can generate most of the 200 cell types
in the human body and have long been touted as key to repairing and
regenerating tissues and organs.
But the challenge has been in gathering enough of the rare cells to have
a meaningful outcome for patients undergoing procedures such as bone
marrow transplants in the treatment of leukemia.
By using sonic hedgehog to mass produce stem cells, Bhatia sees
application to a broad range of problems.
Specifically, Bhatia hopes sonic hedgehog can be used to trigger growth
of new cells to replace brain cells or neurons destroyed by such
diseases as Parkinson's and Alzheimer's or islet cells damaged by
diabetes.
Increasing blood cells in the lab in the case of bone marrow transplants
would decrease the amount of marrow needed and potentially make it
easier to find donors. And as an international leader in spinal-cord
injury research, Bhatia said London scientists will also focus on the
molecule's potential to repair such devastating injuries.
Unlike some discoveries in basic science, Bhatia said sonic hedgehog's
role in proliferating stem cells has huge potential to have a direct
impact on patients.
"Potentially, we could take bone marrow cells, purify these cells,
expand their number, switch them over to neurons and then transplant
them back into a spinal-cord injury patient to re-establish that brain
connection and repair the injured site."
In cancer treatment, in which chemotherapy and radiation targeting a
tumour often takes a heavy toll on the blood system, Bhatia envisions
transplanting stem cells back into the patient, "rescuing the blood
system" without interrupting therapy.
Bhatia says Robarts' greatest contribution will be "creating model
systems" to help repopulate the immune system with healthy cells.
The next step is to transplant human stem cells into mice to study those
outcomes.
Copyright (c) 2001 The London Free Press, a division of Sun Media
Corporation.
Copyright © 2001, Canoe Limited Partnership. All rights reserved.
--
Judith Richards, London, Ontario, Canada
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