Technique holds promise for spinal cord repair in humans

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Hello all:

I know this spinal cord related, but it is the nervous system.

http://www.eurekalert.org/pub_releases/2006-02/uops-enj021606.php

Engineering nerve jumper cables for spinal cord repair in animal model

Technique holds promise for spinal cord repair in humans

Researchers at the University of Pennsylvania School of Medicine have

created – in a rodent model – a completely new way to engineer nerve

structures, or constructs, in culture. This proof-of-principle

research has implications for eventually becoming a new method to

repair spinal cord injury in humans. The work appears in the latest

issue of Tissue Engineering.

" We have created a three-dimensional neural network, a mini nervous

system in culture, which can be transplanted en masse, " explains

senior author H. , MD, Professor, Department of

Neurosurgery and Director of the Center for Brain Injury and Repair at

Penn. Previously, 's group showed that they could grow axons by

placing neurons from rat dorsal root ganglia (clusters of nerves just

outside the spinal cord) on nutrient-filled plastic plates. Axons

sprouted from the neurons on each plate and connected with neurons on

the other plate. The plates were then slowly pulled apart over a

series of days, aided by a precise computer-controlled motor system.

In this study, the neurons were elongated to 10mm over seven days –

after which they were embedded in a collagen matrix (with growth

factors), rolled into a form resembling a jelly roll, and then

implanted into a rat model of spinal cord injury.

" That creates what we call a nervous-tissue construct, " says .

" We have designed a geometrical arrangement that looks similar to the

longitudinal arrangement that the spinal cord had before it was

damaged. The long bundles of axons span two populations of neurons,

and these neuron constructs can grow axons in two directions – toward

each other and into the host spinal cord at each side. That way they

can integrate and connect the 'cables' to the host tissue in order to

bridge a spinal cord lesion. "

After the four-week study period, the researchers found that the

geometry of the construct was maintained and that the neurons at both

ends and all the axons spanning these neurons survived

transplantation. More importantly, the axons at the ends of the

construct adjacent to the host tissue did extend through the collagen

barrier, penetrating into the host tissue. Future studies will measure

neuronal electrical conductivity across the newly engineered bridge

and restoration of motor activity.

" The really great news – and there's still much work to be done – is

that the construct survives and also integrates with host tissue, "

says . " We find this very promising. In particular, this new

technique provides a means to bridge even very long spinal lesions

that are common in humans with spinal cord injury. Now we have to test

whether the transplanted constructs convey a signal all the way

through, and we're developing and testing a new animal model to allow

us to test whether this new technique improves function. "

###

Study co-authors are Akira Iwata, D. Browne, J. Pfister,

all from Penn; and A. Gruner, from Cephalon Inc., West Chester,

PA. The research was funded by the National Institutes of Health and

the Sharpe Trust.

This release and related images can be found at

http://www.uphs.upenn.edu/news/

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