Researchers regenerate nerve connections after spinal injury


August 8, 2010

Deep dissection of brain-stem with the corticospinal tract visible in red

Deep dissection of brain-stem with the corticospinal tract visible in red

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According to the Christopher & Dana Reeve Foundation, about two percent of Americans – more than six million people – have some form of paralysis resulting from spinal cord injury, which is due primarily to the interruption of connections between the brain and spinal cord. Such paralysis and loss of function has long been considered untreatable, but a new approach has, for the first time, induced robust regeneration of nerve connections that control voluntary movement, showing the potential for new therapeutic approaches to paralysis and other motor function impairments and offering hope to sufferers.

In a study on rodents, researchers at UC Irvine (UCI), UC San Diego (UCSD) and Harvard University, achieved this breakthrough by turning back the developmental clock in a molecular pathway critical for the growth of corticospinal tract nerve connections. The corticospinal tract is a collection of axons – the long, slender projections of a nerve cell that conduct electrical impulses – that travel between the cerebral cortex and the spinal cord that is concerned specifically with discrete voluntary skilled movements.

They did this by deleting an enzyme called PTEN (a phosphatase and tensin homolog), which controls a molecular pathway called mTOR that is a key regulator of cell growth. PTEN activity is low early during development, allowing cell proliferation. PTEN then turns on when growth is completed, inhibiting mTOR and precluding any ability to regenerate.

Trying to find a way to restore early-developmental-stage cell growth in injured tissue, Zhigang He, a senior neurology researcher at Children’s Hospital Boston and Harvard Medical School, first showed in a 2008 study that blocking PTEN in mice enabled the regeneration of connections from the eye to the brain after optic nerve damage.

He then partnered with Oswald Steward of UCI and Binhai Zheng of UCSD to see if the same approach could promote nerve regeneration in injured spinal cord sites.

“Until now, such robust nerve regeneration has been impossible in the spinal cord,” said Steward, anatomy & neurobiology professor and director of the Reeve-Irvine Research Center at UCI. “Paralysis and loss of function from spinal cord injury has been considered untreatable, but our discovery points the way toward a potential therapy to induce regeneration of nerve connections following spinal cord injury in people.”

An injury the size of a grape can lead to complete loss of function below the level of injury. For example, an injury to the neck can cause paralysis of arms and legs, loss of ability to feel below the shoulders, inability to control the bladder and bowel, loss of sexual function, and secondary health risks including susceptibility to urinary tract infections, pressure sores and blood clots due to an inability to move the legs.

“These devastating consequences occur even though the spinal cord below the level of injury is intact,” Steward noted. “All these lost functions could be restored if we could find a way to regenerate the connections that were damaged.”

He and his colleagues are now studying whether the PTEN-deletion treatment leads to actual restoration of motor function in mice with spinal cord injury. Further research will explore the optimal timeframe and drug-delivery system for the therapy.

Results of the research team’s study appear online in Nature Neuroscience.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag. All articles by Darren Quick

I would love to see this technology used for regenerating teeth . Senior citizens have a terrible problem from 50 years old on to death. Having teeth problems can result in death from inflamation. Most of the time a person would not know about the inflamation until it\'s too late. Most of us after 65 years old have no insurance after retiring. There is insurance available, but so prohibitively expensive, it isn\'t worth it. It\'s obvious that the growth pattern in the mouth for teeth works twice. Why couldn\'t it work three times, or more? I have read that stem cells work too. Why aren\'t dentists working to perfect this technology? I\'ll tell you. Because it would end their profession. So it\'s up to researchers to do the job. Those of us that are suffering need your help. There are millions of people around the world that are suffering from dental problems. Maybe research into these areas can help. Why not?


Hope is POSITIVE with such findings...

Leong Hee Chan

There are 10000 or more proteins in the blood. The blood changes from fetal to adult ontology. Irrigate regenerating neural tissues with fetal blood instead of adult blood.


'about two percent of Americans â€" more than six million people' have some form of paralysis resulting from spinal cord injury, It's unbelievable! Total number of people with Spinal Cord Injury: Current estimates are 250,000 - 400,000 individuals living with Spinal Cord Injury or Spinal Dysfunction. Number of New Injuries per Year: 32 injuries per million population or 7800 injuries in the US each year

Facebook User

luckyfella1 has it right! I\'m one of those suffering from tooth loss and can\'t afford the insurance let alone paying the deductibles or portions that insurance does not pay! My only option is to have the teeth pulled & chew with what I have left but even that has to be done by an orthodontist now who charges three times as much! Can\'t find a regular dentist who will tackle it! Seems they don\'t want the risk!

Will, the tink
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