Rodent of the Week: Nerves regenerated after spinal cord injury [Updated]

The long-sought goal of helping paralyzed people regain some ability to move is a step closer after researchers announced they had induced nerve regeneration in mice with severe spinal cord injury.

A team of researchers from UC Irvine, UC San Diego and Harvard deleted an enzyme called PTEN (a phosphatase and tensin homolog), which controls a specific molecular pathway that regulates cell growth. PTEN activity is low during development and then turns on when growth is completed. Previously, researchers showed they could block PTEN in mice to regenerate nerve connections from the eye to the brain after optic nerve damage. The new research demonstrates that such nerve regeneration could take place in the injured spinal cord.

The study’s results “indicate that PTEN deletion enables injured adult corticospinal neurons to mount a robust regenerative response that, to the best of our knowledge, has not been observed previously in the mammalian spinal cord,” the authors wrote.

The authors noted that, although neuron growth was seen, it was not achieved in specific areas of the injury. More research remains to achieve regeneration throughout the injured area. Another critical step will be to see if the PTEN-deletion treatment allows the injured mice to regain motor function. Questions also remain about the optimal timing of the treatment and how the drugs should be delivered for the greatest effect.

The study was published Sunday in the journal Nature Neuroscience.

-- Shari Roan / Los Angeles Times

[For the record, 9:38 a.m. Aug. 18: An earlier version of this post incorrectly said PTEN turned off when growth was completed. It actually turns on.]

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