In Breakthrough, Nerve Connections Are Regenerated After Spinal Cord Injury

[n2doc]

ScienceDaily (Aug. 9, 2010) — Researchers for the first time have induced robust regeneration of nerve connections that control voluntary movement after spinal cord injury, showing the potential for new therapeutic approaches to paralysis and other motor function impairments.

In a study on rodents, the UC Irvine, UC San Diego and Harvard University team achieved this breakthrough by turning back the developmental clock in a molecular pathway critical for the growth of corticospinal tract nerve connections.

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. Results of their study appear online in Nature Neuroscience.

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http://www.sciencedaily.com/releases/2010/08/100808212800.htm

Hope this work translates into humans. A cure for paralysis would be incredible.

[opihimoimoi]

1. SEE WHAD SCIENCE can do for MANKIND,,,This is awesome

KnR big time

[arendt]

2. This is far away from a cure...

You don't just "delete PTEN".

PTEN is a major anti-cancer gene. Its true that PTEN is off during early growth. But, it has to be on in adulthood, or you get cancer really easily. No problem if you are a lab mouse; big problem if you are a human medical patient.

So, I view this publication as basic research into understanding the pathway; but not as clinical research for curing the problem. To create a cure, they have to find a way to LOCALLY AND TEMPORARILY turn off PTEN to allow regeneration, and then turn it back on again. And, those things are beyond our capabilities at the moment.

So, hooray for basic research; but don't expect a cure for a while.

[n2doc]

3. Couldn't they use a drug that locally inhibits PTEN?

I wonder if the SN article is not using the right words for this. I haven't read the Nature article, though.

[arendt]

5. Localizing a drug interaction is VERY HARD

Off the top of my head, I can't come up with any examples. When you hear about targeted "drugs", they are usually talking monoclonal antibodies or some exotic biophysical system(e.g., where you bind drugs to metal nanocubes and use magnets to move them).

Getting garden variety drugs (small molecules) to localize - scientists don't know how to do that. It takes ten years to get them just to design a molecule that can:

- get to the target
- stick to it long enough to do the job
- doesn't have any off-target interactions (think Celebrex)
- can be broken down without any toxins being produced.

You have to do all of that with a molecular weight of around 500. Adding specificity for a certain sub-population of cells (where the sub-population is of interest to the medicos, but not to the body, per se) is just way beyond state-of-the-art.

That's why I say this is more about basic research into how to turn cells on and off, than applied research to create a "drug". I just don't see this being managed with a drug.

[n2doc]

6. Thats for pills?

If one used a local direct infusion, that might get around many of those problems, and would be appropriate for this type of injury. But you are probably right, still a long ways off from something useful.

[MineralMan]

4. It's more a pathway to further research.

The cancer issue is a major one with messing with PTEN. But, it's excellent basic research. Now...they'll turn to a more focused research program to see if this can be used safely in humans some way. Good news, though.