Stem Cells Rescue Nerve Cells By Direct Contact

February 3, 2010

Scientists at the Swedish medical university Karolinska Institutet have shown

how transplanted stem cells can connect with and rescue threatened neurons and

brain tissue. The results point the way to new possible treatments for brain

damage and neurodegenerative diseases.

A possible strategy for treating neurodegenerative diseases is to transplant

stem cells into the brain that prevent existing nerve cells from dying. The

method has proved successful in different models, but the mechanisms behind it

are still unknown. According to one hypothesis, the stem cells mature into

fully-mature neurons that communicate with the threatened brain tissue;

according to another, the stem cells secrete various growth factors that affect

the host neurons.

The new report, co-authored by several international research groups and lead by

Karolinska Institutet, shows that stem cells transplanted into damaged or

threatened nerve tissue quickly establish direct channels, called gap junctions,

to the nerve cells. Stem cells actively bring diseased neurons back from the

brink via cross-talk through gap junctions, the connections between cells that

allow molecular signals to pass back and forth. The study found that the nerve

cells were prevented from dying only when these gap junctions were formed. The

results were obtained from mice and human stem cells in cultivated brain tissue,

and from a series of rodent models for human neurodegenerative diseases and

acute brain injuries.

" Many different molecules can be transported through gap junctions, " says

Herlenius, who led the study. " This means that a new door to the possible future

treatment of neuronal damage has been opened, both figuratively and literally. "

The international team of scientist, beside Karolinska Institutet, included

researchers from Sanford-Burnham Medical Research Institute, Harvard Medical

School and Université Libre de Bruxelles.

Publication: " Communication via gap junctions underlies early functional and

beneficial interactions between grafted neural stem cells and the host " , Johan

Jäderstad, M. Jäderstad, Jianxue Li, Satyan Chintawar, Carmen Salto,

Massimo Pandolfo, Vaclav Ourednik, Yang D. Teng, L. Sidman, Ernest

Arenas, Evan Y. Snyder and Herlenius, PNAS Online Early Edition, 1 Feb

2010.

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