In a recent TV commercial the quadraplegic actor Cristopher Reeve rises and walks across a stage. Sadly, the state-of-the-art computer graphics that were used to create the spot are all that todays technology can do to help the victims of spinal cord injury walk again.
But in a new study, researchers have found a way to help repair spinal cord injuries in animals up to 24 hours after they happen. The miracle substance? A chemical related to anti-freeze and acne medicine.
What Did They Discover?
A team of researchers at the Center for Paralysis Research at Purdue Universitys School of Veterinary Medicine showed that polyethylene glycol (PEG)—a hydrophilic (water-loving) chemical used in a variety of products, including a popular face cleanser—aids spinal cord injuries (SCI) if applied within the next 24 hours.
|Richard Borgens (pointing) and a student.|
"What PEG does when we apply it to an injured spinal cord is that it seals the injury to individual cell membranes," says Richard Borgens, a member of the team who has been studying the effects of SCI for some 20 years. "And when that occurs almost immediately, within minutes were able to see a recovery of function. That means... a recovery of conduction, which is the traffic of nerve impulses through the spinal cord injury."
In nerve impulse conduction tests with rats and guinea pigs, 100% of the animals tested with PEG treatment recovered conduction, while none of the control animals regained any. In tests for skin rippling—a measure for spinal cord recovery—more than 90% recovered some function when treated with PEG, as opposed to 17% of controls.
What Is SCI?
Before World War II SCI was often fatal within weeks of the injury due to urinary dysfunction, respiratory infection or bedsores. Although that is no longer the case, todays SCI patients face a life of paralysis. Some 450,000 Americans are living with SCI, the effects of which range from the absence of fine motor skills to the inability to move or breathe on ones own.
"When a person is injured in an... accident, what actually occurs to the spinal cord is its usually compressed severely, and the areas of nerve fibers which we call white matter are damaged," Borgens explains. "Most spinal cord injuries are compression injuries. The neck is bent severely," resulting in bruising of the cord.
This bruising and compression damages the ability of motor nerves to conduct the impulses which control our ability to physically move and feel. The pathway between the brain and the affected area of the body is broken (see animation at right). But unlike broken bones or flesh, spinal cords lack the capacity to heal from injury, so even a simple event like falling at home can result in paralysis, and a tiny area of damage can cause lifelong paralysis.
Will People Receive PEG Treatment?
Based on their current success, Borgenss team will move on to the final phase of their project: treating dogs with naturally occurring spinal cord injuries (caused, for instance, by car accidents). And while he hopes that PEG might be tested on humans within two years, Borgens emphasizes that PEG wont be found in hospital emergency rooms any time soon.
|image: Medical Educational Resources Program, Indiana University|
He also cautions that PEG is not a cure-all. "PEG is not really applicable to an injury that is five years old, or [even] one year old," he says. Aside from the short window of effectiveness, there are substantial risks as well: PEG must be flushed from the cord within two to three minutes of application, or it will cause even more damage to the spinal cord than it fixes.
So while PEG may not help Christopher Reeve or the other thousands of SCI patients recover normal function, it promises to be a treatment for traumatic injuries in the future. Borgens sees PEG as an effective treatment to help newly-injured patients recover at least some functioning. "Its quality of life changes which I believe are the most important goal for SCI research now."
Elsewhere on the web:
Reeve-Irvine Spinal Cord Injury Research Center
National Spinal Cord Injury Association
Purdue University Veterinary School
Cure Paralysis Now Link Page
Christopher Reeve Paralysis Organization
Spinal Cord Society
Disabled American Veterans