1 small step for neurons, 1 giant leap for nerve cell repair

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1 small step for neurons, 1 giant leap for nerve cell repair

Scientists create nerve cell connections in vitro using artificial substances, a

major advance towards nerve cell repair

http://www.eurekalert.org/pub_releases/2009-10/mu-oss100709.php

The repair of damaged nerve cells is a major problem in medicine today. A new

study by researchers at the Montreal NeurologicaI Institute and Hospital (The

Neuro) and McGill University, is a significant advance towards a solution for

neuronal repair. The study featured on the cover of the October 7 issue of

Journal of Neuroscience, is the first to show that nerve cells will grow and

make meaningful, functional contacts, or synapses - the specialized junctions

through which neurons signal to each other - with an artificial component, in

this case, plastic beads coated with a substance that encourages adhesion, and

attracts the nerve cells.

" Many therapies, most still in the conceptual stage, are aimed at restoring the

connection between the nerve cell and the severed nerve fibres that innervate a

target tissue, typically muscle, " says Dr. Colman, Director of The Neuro

and principal investigator in the study. " Traditional approaches to therapies

would require the re-growth of a severed nerve fibre a distance of up to one

meter in order to potentially restore function. The approach we are using

however bypasses the need to force nerve cells to artificially grow these long

distances, and eliminates the demand for two neurons to make a synapse, both of

which are considerable obstacles to neuronal repair in a damaged system. "

" We are tackling this problem in an entirely new way, as part of the McGill

Program in NeuroEngineering, " says Dr. Lucido, who conducted research

for the study as part of her PhD research at The Neuro and is currently a

post-doctoral fellow at UCSF. " This program, spearheaded by Dr. Colman, is a

multi-disciplinary consortium that brings together the knowledge, expertise and

perspectives of 40 scientists from diverse fields to focus on the challenge of

neuronal repair in the central nervous system. The approach we have taken is to

help healthy nerve cells form functional contacts with artificial substrates in

order to create a paradigm that can be adapted to model systems in which neurons

are damaged. That approach will be combined with strategies to encourage the

outgrowth of damaged neuronal branches through which these connections, or

synapses, are formed. It's a challenging endeavour, but the ability to trigger

connections to form on command is a promising start. Our ultimate goal is to

create a combined platform in which damaged cells could be encouraged to both

re-grow and re-establish their functional connections. "

The synapses generated in this study are virtually identical to their natural

counterparts except the 'receiving' side of the synapse is an artificial plastic

rather than another nerve cell or the target tissue itself. This study is the

first, using these particular devices, to show that adhesion is a fundamental

first step in triggering synaptic assembly.

" Even though components of synapses have been induced in similar earlier

studies, their functionality was not proven. In order to assess function - that

is transmission of a signal from the synapse, we stimulated the nerve cells with

electricity, sending the signal, an action potential, to the synapse. By

artificially stimulating nerve cells in the presence of dyes, we could see that

transmission had taken place as the dyes were taken up by the synapses. "

" We believe that within the next five years we will have a fully functional

device that will be able to directly convey natural nerve cell signals from the

nerve cell itself to an artificial matrix containing a mini-computer that will

communicate wirelessly with target tissues, " says Dr. Colman. These results not

only provide a model to understand how neurons are formed which can be employed

in subsequent studies but, provides hope for those affected and potentially

holds promise for the use of artificial substrates in the repair of damaged

nerves.

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About the Montreal Neurological Institute and Hospital

Celebrating 75 years

The Montreal Neurological Institute and Hospital (The Neuro) is a unique

academic medical centre dedicated to neuroscience. The Neuro is a research and

teaching institute of McGill University and forms the basis for the Neuroscience

Mission of the McGill University Health Centre. Founded in 1934 by the renowned

Dr. Wilder Penfield, The Neuro is recognized internationally for integrating

research, compassionate patient care and advanced training, all key to advances

in science and medicine. Neuro researchers are world leaders in cellular and

molecular neuroscience, brain imaging, cognitive neuroscience and the study and

treatment of epilepsy, multiple sclerosis and neuromuscular disorders. For more

information, please visit www.mni.mcgill.ca.