Neurologically Impaired Mice Improve After Receiving Human Stem Cells

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Neurologically Impaired Mice Improve After Receiving Human Stem Cells

07 Jun 2008

http://www.medicalnewstoday.com/articles/110081.php

Scientists report a dramatic success in what may be the first

documented rescue of a congenital brain disorder by transplantation of

human neural stem cells. The research, published by Cell Press in the

June issue of the journal Cell Stem Cell, may lead the way to new

strategies for treating certain hereditary and perinatal neurological

disorders.

Nerve cell projections are ensheathed by a fatty substance called

myelin that is produced by oligodendrocytes, a type non-nerve cell in

the brain and spinal cord. Myelin enhances the speed and coordination

of the electrical signals by which nerve cells communicate with one

another. When myelin is missing or damaged, electrical signals are not

properly transmitted. Previous studies have explored the potential

utility of cell transplantation for restoring absent or lost

myelination to diseased nerve fibers. Much of this research has made

use of the 'shiverer mouse' animal model which lacks normal myelin and

typically dies within months of birth. Yet to date, no transplantation

of human neural stem cells or of their derivatives, called glial

progenitor cells, have ever altered the condition or fate of recipient

animals.

Dr. Steve Goldman and colleagues from the Departments of Neurology and

Neurosurgery at the University of Rochester Medical Center, along with

collaborators at Cornell, UCLA and Baylor, built on this earlier work

by devising a more robust method for the acquisition and purification

of human fetal glial progenitor cells. In addition, they developed a

new cell delivery strategy, based on multiple injection sites, to

encourage widespread and dense donor cell engraftment throughout the

central nervous system of recipient mice. The researchers transplanted

human glial stem cells into neonatal shiverer mice that also had a

genetically deficient immune system. Immunodeficient mice were used to

minimize the rejection of the transplanted cells.

The researchers found that the new transplant procedure resulted in

infiltration of human glial progenitor cells throughout the brain and

spinal cord. The engrafted mice exhibited robust, efficient and

functional myelination. Most notably, many of the mice displayed

progressive, neurological improvement and a fraction of the mice were

actually rescued by the procedure. " The neurological recovery and

survival of the mice receiving transplants was in sharp contrast to

the fate of their untreated controls, which uniformly died by five

months, " explains Dr. Goldman. Upon histological examination well over

a year after the procedure, the white matter of the surviving mice had

been essentially re-myelinated by human cells.

" To our knowledge, these data represent the first outright rescue of a

congenital hypomyelinating disorder by means of stem or progenitor

cell transplantation, " offers Dr. Goldman. " Although much work needs

to be done to maximize the number of individuals that respond to

transplantation, I think that these findings hold great promise for

the potential of stem cell-based treatment in a wide range of

hereditary and ischemic myelin disorders in both children and adults. "