Monday, September 21, 2009

Scientists Make Paralyzed Rats Walk Again After Spinal Cord Injury

UCLA researchers have discovered that a combination of drugs, electrical stimulation and regular exercise can enable paralyzed rats to walk and even run again while supporting their full weight on a treadmill.

Published Nov. 20 in the online edition of Nature Neuroscience, the findings suggest that the regeneration of severed nerve fibers is not required for paraplegic rats to learn to walk again. The finding may hold implications for human rehabilitation after spinal cord injuries.

"The spinal cord contains nerve circuits that can generate rhythmic activity without input from the brain to drive the hind leg muscles in a way that resembles walking called 'stepping,'" explained principal investigator Reggie Edgerton, a professor of neurobiology and physiological sciences at the David Geffen School of Medicine at UCLA.

"Previous studies have tried to tap into this circuitry to help victims of spinal cord injury," he added. "While other researchers have elicited similar leg movements in people with complete spinal injuries, they have not achieved full weight-bearing and sustained stepping as we have in our study."

Edgerton's team tested rats with complete spinal injuries that left no voluntary movement in their hind legs. After setting the paralyzed rats on a moving treadmill belt, the scientists administered drugs that act on the neurotransmitter serotonin and applied low levels of electrical currents to the spinal cord below the point of injury.

The combination of stimulation and sensation derived from the rats' limbs moving on a treadmill belt triggered the spinal rhythm-generating circuitry and prompted walking motion in the rats' paralyzed hind legs.

Daily treadmill training over several weeks eventually enabled the rats to regain full weight-bearing walking, including backwards, sideways and at running speed. However, the injury still interrupted the brain's connection to the spinal cord-based rhythmic walking circuitry, leaving the rats unable to walk of their own accord.

Neuro-prosthetic devices may bridge human spinal cord injuries to some extent, however, so activating the spinal cord rhythmic circuitry as the UCLA team did may help in rehabilitation after spinal cord injuries.

The study was funded by the Christopher and Dana Reeve Foundation, Craig Nielsen Foundation, National Institute of Neurological Disorders and Stroke, U.S. Civilian Research and Development Foundation, International Paraplegic Foundation, Swiss National Science Foundation and the Russian Foundation for Basic Research Grants.

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Tuesday, September 01, 2009

New data on Paralysis Could Impact Future Treatment Strategies

Sufficient information on the prevalence of Americans living with paralysis and spinal cord injuries (SCI) has always been hard to come by. Most information cited in educational literature and on many Web sites regarding paralysis and SCI is extremely outdated. This presents numerous hurdles in devising new or evaluating existing policies, programs, and services for people living with these types of disabilities.

In 2004, The Christopher & Dana Reeve Foundation brought together a task force of more than 60 scientists, scholars, health advocates, and experts from the U.S. Centers for Disease Control and Prevention (CDC) and numerous universities, policy centers, and nonprofit health care organizations to identify what was needed to improve the quality of life for people living with paralysis. In order to complete this complex initiative, the Paralysis Task Force first needed to obtain more recent data on the individuals they were trying to assist.

With support from the University of New Mexico?s Center for Development and Disability (CDD) in partnership with the Christopher & Dana Reeve Foundation?s Paralysis Resource Center (PRC), researchers designed and conducted a survey of more than 33,000 households across the country??one of the largest population-based samples of any disability ever conducted. The new data demonstrates that paralysis may be dramatically more widespread than previously thought.

Below are some of the report?s major findings:
  • Approximately 1.9 percent of the U.S. population, or 5,596,000 people reported they were living with some form of paralysis, defined by the study as a central nervous system disorder resulting in difficulty or inability to move the upper or lower extremities. This is about one-third more Americans living with paralysis than previously estimated (4 million).
  • The leading cause of paralysis was stroke (29 percent), followed by spinal cord injury (23 percent) and multiple sclerosis (17 percent).
  • Data indicate that 1,275,000 people in the United States are living with spinal cord injury?more than five times the number of Americans previously estimated in 2007 (255,702).


These findings have major implications for the treatment of spinal cord and paralysis-related diseases?not only for those living with these conditions, but also for their families, caregivers, health care providers, and employers. As the number of people living with paralysis and spinal cord injuries increases, for example, so do the costs associated with treating them. Each year, paralysis and spinal cord injuries cost the health care system billions of dollars. Spinal cord injuries alone cost roughly $40.5 billion annually?a 317 percent increase from costs estimated in 1998 ($9.7 billion),? the report states.

If you have yet to read this important report conducted by the Christopher and Dana Reeve Foundation, you can access the 28-page PDF here.

By NY Disability Examiner Tom Scott

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