Researchers engineer cell tissue to repair nerve damage

February 29th, 2008 - 12:28 am ICT by admin  

Washington, Feb 28 (IANS) Live human nerve cells can be patched on to a network for use in future transplants to repair damage to the nervous system, according to a study. “We have created a three-dimensional neural network, a mini nervous system in culture, which can be transplanted en masse,” explained the study’s co-author Douglas H. Smith, of the Centre for Brain Injury and Repair at Pennsylvania.

“This study demonstrates the promise of adult neurons as an alternative transplant material due to their availability, viability, and capacity to be engineered,” said Smith.

Smith’s group demonstrated they could induce tracts of nerve fibres called axons to grow in response to mechanical tension. They placed 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, creating long tracts of living axons.

These cultures were then embedded in a collagen matrix, rolled into a form resembling a jelly roll, and then implanted into a rat model of spinal cord injury. 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.

Next, the researchers harvested root ganglia neurons from 16 patients and four thoracic neurons were harvested from organ donors. The neurons were purified and placed in a specially designed growth chamber. Using the stretch growth technique, the axons were slowly pulled in opposite directions over days until they reached the desired length.

The neurons survived at least three months in culture while maintaining the ability to generate action potentials, the electrical signals transmitted along nerve fibres. The axons grew at about 1 millimetre per day to a length of 1 centimetre, creating the first engineered living human nervous tissue constructs.

The findings have been reported in the February issue of the Journal of Neurosurgery.

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