All About Multiple Sclerosis

More MS news articles for November 2002

Polymer implant promotes axon growth in rat model of SCI

01 December 2002
The Lancet Neurology
Volume 1, Number 8
Thomas S May

An innovative technique, which could lead to a cure for paralysis caused by spinal-cord injury (SCI) within the next 3–7 years, has been developed by scientists at the Mayo Medical School in Rochester, Minnesota (USA). “We have assembled a team of leading neurobiologists, tissue engineers, polymer chemists, neurosurgeons, and orthopaedic surgeons committed to work on this project and make it succeed”, dean Anthony Windebank told The Lancet Neurology.

Lead researcher Jonathan Friedman and colleagues have used a novel biodegradable polymer implant to bridge a 3 mm gap in the rat spinal cord. The poly-lactic-co-glycolic acid (PLGA) implant functions both as a scaffold to support axon growth across the gap and as a conduit for the delivery of agents that promote axon regeneration.

“We have demonstrated robust axon growth through the implant in the transected rat spinal-cord model”, said Friedman, who presented the findings at the 127th annual meeting of the American Neurological Association in New York City (NY, USA; Oct 13–16). “Functional studies are ongoing”, he added, “but based on our preliminary data, we feel that ultimately there is significant promise for the direct application of such an implant into the human spinal cord following injury, such that motor and sensory neurologic function might be effectively restored in patients who have suffered SCI”.

In order to optimise the cellular environment inside the conduit, the researchers populated the graft with Schwann cells isolated from the sciatic nerves of 3-day-old rats. The implant was also used to deliver chondroitinase ABC, an enzyme that degrades proteoglycans, which are thought to play a key role in the inhibitory local response to SCI.

The researchers report that 3 months after implantation, animals with the polymer grafts (seeded with Schwann cells) did “slightly better” than controls on the Basso, Beattie, and Bresnahan scale, which is used to measure functional performance. Furthermore, the animals with implants did not experience any more adverse events, such as infections, than animals in the control group.

According to Michael Fehlings (University of Toronto, ON, Canada), successful regenerative approaches to treat SCI will require a combination of strategies. This work is an important step forward, he says, because it combines cellular therapy with bio-implantable tubes. “The implantable tubes have the advantage of providing a conduit to direct growth and for the delivery of small molecules to facilitate nerve cell repair and regeneration”, Fehlings said.

© Copyright 2002, The Lancet Neurology