New procedure repairs severed nerves in minutes, restoring limb use in days or weeks

American scientists believe a new procedure to repair severed nerves could result in patients recovering in days or weeks, rather than months or years. The team used a cellular mechanism similar to that used by many invertebrates to repair damage to nerve axons. Their results are published today in the Journal of Neuroscience Research.

"We have developed a procedure which can repair severed nerves within minutes so that the behavior they control can be partially restored within days and often largely restored within two to four weeks," said Professor George Bittner from the University of Texas. "If further developed in this approach would be a great advance on current procedures that usually imperfectly restore lost function within months at best."

The team studied the mechanisms all use to repair damage to their membranes and focused on invertebrates, which have a superior ability to regenerate nerve axons compared to . An axon is a long extension arising from a nerve cell body that communicates with other or with muscles.

This research success arises from Bittner's discovery that nerve axons of invertebrates which have been severed from their cell body do not degenerate within days, as happens with mammals, but can survive for months, or even years.

The severed proximal nerve axon in can also reconnect with its surviving distal nerve axon to produce much quicker and much better restoration of behaviour than occurs in mammals.

"Severed invertebrate nerve axons can reconnect proximal and distal ends of severed nerve axons within seven days, allowing a rate of behavioural recovery that is far superior to mammals," said Bittner. "In mammals the severed distal axonal stump degenerates within three days and it can take nerve growths from proximal axonal stumps months or years to regenerate and restore use of muscles or sensory areas, often with less accuracy and with much less function being restored."

The team described their success in applying this process to rats in two research papers published today. The team were able to repair severed sciatic nerves in the upper thigh, with results showing the rats were able to use their limb within a week and had much function restored within 2 to 4 weeks, in some cases to almost full function.

"We used rats as an experimental model to demonstrate how severed nerve axons can be repaired. Without our procedure, the return of nearly full function rarely comes close to happening," said Bittner. "The sciatic nerve controls all muscle movement of the leg of all mammals and this new approach to repairing could almost-certainly be just as successful in humans."

To explore the long term implications and medical uses of this procedure, MD's and other scientist- collaborators at Harvard Medical School and Vanderbilt Medical School and Hospitals are conducting studies to obtain approval to begin clinical trials.

"We believe this procedure could produce a transformational change in the way injuries are repaired," concluded Bittner.

Related Stories

In reversing motor nerve damage, time is of the essence

Oct 03, 2011

When a motor nerve is severely damaged, people rarely recover full muscle strength and function. Neuroscientists from Children's Hospital Boston, combining patient data with observations in a mouse model, now show why. It's ...

Breathing restored after spinal cord injury

Jul 13, 2011

Researchers at Case Western Reserve University School of Medicine bridged a spinal cord injury and biologically regenerated lost nerve connections to the diaphragm, restoring breathing in an adult rodent model of spinal cord ...

Lab-grown nerves promote nerve regeneration after injury

Mar 19, 2009

Researchers at the University of Pennsylvania School of Medicine have engineered transplantable living nerve tissue that encourages and guides regeneration in an animal model. Results were published this month in Tissue En ...

Spinal cord bridge bypasses injury to restore mobility

Aug 17, 2006

The body's spinal cord is like a super highway of nerves. When an injury occurs, the body's policing defenses put up a roadblock in the form of a scar to prevent further injury, but it stops all neural traffic from moving ...

Race to nerve regeneration: faster is better

Oct 03, 2011

A team of researchers led by Clifford Woolf and Chi Ma, at Children's Hospital Boston and Harvard Medical School, Boston, has identified a way to accelerate the regeneration of injured peripheral nerves in mice such that ...

Recommended for you

Steering the filaments of the developing brain

13 hours ago

During brain development, nerve fibers grow and extend to form brain circuits. This growth is guided by molecular cues (Fig. 1), but exactly how these cues guide axon extension has been unclear. Takuro Tojima ...

Do we really only use 10% of our brain?

13 hours ago

As the new film Lucy, starring Scarlett Johansson and Morgan Freeman is set to be released in the cinemas this week, I feel I should attempt to dispel the unfounded premise of the film – that we only use 10% of our brains ...

Birthday matters for wiring-up the brain's vision centers

Jul 31, 2014

Researchers at the University of California, San Diego School of Medicine have evidence suggesting that neurons in the developing brains of mice are guided by a simple but elegant birth order rule that allows them to find ...

User comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Squirrel
5 / 5 (5) Feb 03, 2012
Something has been cut. The abstract explains the missing procedure:
"severed axonal ends are opened and resealing is prevented by hypotonic Ca free saline containing antioxidants (especially methylene blue) that inhibit plasmalemmal sealing in sciatic nerves. Second, a hypotonic solution of polyethylene glycol (PEG) is applied to open closely apposed (by microsutures, if cut) axonal ends to induce their membranes to ow rapidly into each other .."
Rapid, Effective, and Long-Lasting Behavioral Recovery Produced by Microsutures, Methylene Blue, and Polyethylene Glycol After Completely Cutting Rat Sciatic Nerves
G.D. Bittner, et al Journal of Neuroscience Research Early View publication
dogbert
not rated yet Feb 03, 2012
Thanks, Squirrl, for the missing details.

Very promising intervention. I wonder if these procedures are applicable to severed spinal nerves?
hemitite
not rated yet Feb 03, 2012
Sounds like a job for some sort of biochemical crimp on connector.
MrVibrating
not rated yet Feb 03, 2012
Manually splicing individual axons one at a time isn't going to be a viable procedure for a good while, i'd've thought. For now, it may be a case of something's better than nothing, but isn't going to be practical for restoring full sensory and motor control in severe injuries like a re-attached limb or major nerve bundle... or am i being too cynical? Cool advance all the same, i've read before about how protein transport continues along severed axons causing jams and ultimately plaque development followed by necrosis. Re-attaching them is the only way to keep them viable - there's no artificial means to take over the cell's role in controlling the protein transport mechanism that might otherwise allow prosthetic neural integration - hence current alternatives must directly stimulate the muscles with electrodes. Being able to fix axons immediately is almost the silver bullet... if it can be implemented en masse anyway...
antialias_physorg
5 / 5 (1) Feb 03, 2012
but isn't going to be practical for restoring full sensory and motor control in severe injuries like a re-attached limb or major nerve bundle

That's already being done. Though the procedure is more akin to doing fine sutures and then letting the nerves regrow/reattach themselves (axons can grow at about a millimeter per month or so)

The drawback is that you will not get the same reattachment scheme as before - so you have to relearn the use of the limb and relearn to interpret the sensory data. With the conflicting (old) scheme represented in your brain up until the accident this usually leads to somewhat impaired performance.
MrVibrating
not rated yet Feb 03, 2012
Ah i see, thanks. Wow so notwithstanding a degree of plasticity, this is quite a promising breakthrough then...
antialias_physorg
not rated yet Feb 03, 2012
Yes. Especially for spinal injuries this could be a real breakthrough. I hope they get this to Phase 1 trials soon.

Though what works in mice doesn't always work in humans. We'll just have to wait and see.
jimbo92107
not rated yet Feb 04, 2012
Being able to fix axons immediately is almost the silver bullet... if it can be implemented en masse anyway...


A fibrous scaffolding (spider silk?) impregnated with each of the two chemicals at either end. Simply laid across the gap between the severed ends.