- Experts at the Functional Electrical Stimulation Center at the Cleveland Veterans Affairs Medical Center and Case Western Reserve University in Cleveland have taken a non-biological approach to nerve regeneration. Using miniaturized computers, sensors and electrodes, they have replaced the damaged nervous system with silicon and copper -- a technique known as "neural prostheses."
These nerve substitutes help paraplegics stand and walk, and help quadriplegics reach and grasp objects. An implanted stimulator, similar to a cardiac pacemaker, generates electrical impulses that mimic natural movement patterns. The impulses are transmitted along electrodes to the paralyzed muscles.
This x-ray shows the components of a neural prosthesis that sends signals from an implanted stimulator to electrodes located on arm and hand muscles.
- Since so much nerve destruction occurs during the inflammation that follows injury, the Multicenter Animal Spinal Cord Injury Study, is assessing medicines that might protect nerves after injury. The fast-track effort will compare methylprednisolone, a chemical that reduces damage by protecting neurons' cell membranes and is considered the "gold standard" of treatment for spinal cord injury, to four other drugs. Under the direction of Wise Young of New York University, the project is treating rats with various types of spinal cord injuries with varying dosages of the five drugs.
Protecting neurons in the spinal cord is even more important now that scientists are learning to rejuvenate cells that are alive but not functioning, says Douglas Anderson of the University of Florida. "The more cells you preserve up front, the more you have to turn back on with a graft" or other technique.
- Acorda, a New York biotechnology firm specializing in spinal-cord medicines, is about to embark on a trial of the effectiveness of 4-amino pyradine. 4-AP, one of many pyradine rings with pharmacological properties, increases the ability of a damaged axon to transmit electrical signals. Ron Cohen, Acorda's president, says about 70 people with spinal-cord injury have received it over the past five years.
Although, with so many experimental designs, it's not difficult to tabulate results, he says there has been a striking reduction in a phantom but excruciating pain that's often felt in the paralyzed zone. The drug has also reduced severe spasticity, and some patients have regained sensory or motor functions.
The upcoming trials will test various dosing schedules and check for long-term side effects. Since the drug only compensates for demyelination of axons, it must be given every day. Although the drug is not perfect, Cohen says it is "the first therapy ever to appear to restore some neurological function in people with damaged spinal cord nerves."
- Instead of improving the function of demyelinated neurons (nerve cells that have lost their electrical insulation), some scientists are trying to restore the myelin in the first place, using a variety of biotechnological approaches.
