December 27, 2005

Altered cells deliver Parkinson’s therapy to brain

NEW YORK (Reuters Health) - Genetically modified nerve
'progenitor' cells can be used as mini-pumps to deliver nerve
growth factor to the brain, a new study in animals shows.

The results suggest such an approach could be used to treat
Parkinson's disease and other brain diseases in humans, Dr.
Clive D. Svendsen of the University of Wisconsin-Madison and
colleagues report.

A nerve growth factor called "glial cell line-derived
neurotrophic factor" (abbreviated to GDNF) has been shown to
protect dopamine-producing neurons, which are lost in
Parkinson's disease, Svendsen and his team note in the research
journal Gene Therapy.

In fact, it's safe to infuse GDNF into brain regions of
patients with Parkinson's disease, according to some studies,
and it seems effective. However, delivering the drug in this
fashion is complex and only reaches a single point in the

In the current study, using rats with symptoms akin to
Parkinson's disease, the researchers investigated the effect of
human neural progenitor cells engineered to produce GDNF.

The rats were transplanted with the modified cells, and
after two weeks these were seen to have migrated to affected
areas and to be secreting enough GDNF to extend the survival of
dopamine neurons and promote outgrowth of nerve fibers.

By five weeks post-transplant, the animals showed a "strong
trend toward functional improvement," and at eight weeks the
cells were still releasing the growth factor.

Tests in elderly monkeys showed the cells survived and
continued to release GDNF for three months after transplant.
None of the animals in the studies developed brain tumors.

Svendsen and his colleagues conclude that their results
"show that combining human progenitor cell therapy with ...
gene therapy is a powerful approach to the future treatment of
Parkinson's disease and other neurological conditions."

SOURCE: Gene Therapy, online December 15, 2005.