An evening round brought a young patient without obvious injury lying with minimal movement, beside him is a 'comfortable looking' wheelchair. It looks like this patient has been wheelchair bound for some time. Further query revealed this young 23 years old patient involved in a freak accident during an inspection of his lorry along the expressway. He was left paralysed since the age of 21 when he first started working.
Tears build up within this young chap's mother really brought a message that it is time for technology and advancing medical techniques to bring some light to people with spinal cord injury.
Walking and Running Again After Spinal Cord Injury
Rats with spinal cord injuries and severe
paralysis are now walking (and running) thanks to researchers at EPFL.
Published in the June 1, 2012 issue of Science, the results show that a severed section of the
spinal cord can make a comeback when its own innate intelligence and
regenerative capacity is awakened. The study, begun five years ago at the
University of Zurich, points to a profound change in our understanding of the
central nervous system. According to lead author Grégoire Courtine, it is yet
unclear if similar rehabilitation techniques could work for humans, but the
observed nerve growth hints at new methods for treating paralysis.
"After
a couple of weeks of neurorehabilitation with a combination of a robotic
harness and electrical-chemical stimulation, our rats are not only voluntarily
initiating a walking gait, but they are soon sprinting, climbing up stairs and
avoiding obstacles when stimulated," explains Courtine, who holds the
International Paraplegic Foundation (IRP) Chair in Spinal Cord Repair at EPFL.
Waking
up the spinal cord
It is well known that the brain and spinal cord can adapt and
recover from moderate injury, a quality known as neuroplasticity. But until now
the spinal cord expressed so little plasticity after severe injury that
recovery was impossible. Courtine's research proves that, under certain
conditions, plasticity and recovery can take place in these severe cases -- but
only if the dormant spinal column is first woken up.
To do this, Courtine and his team injected a chemical solution of
monoamine agonists into the rats. These chemicals trigger cell responses by
binding to specific dopamine, adrenaline, and serotonin receptors located on
the spinal neurons. This cocktail replaces neurotransmitters released by
brainstem pathways in healthy subjects and acts to excite neurons and ready
them to coordinate lower body movement when the time is right.
Five to 10 minutes after the injection, the scientists
electrically stimulated the spinal cord with electrodes implanted in the
outermost layer of the spinal canal, called the epidural space. "This
localized epidural stimulation sends continuous electrical signals through nerve
fibers to the chemically excited neurons that control leg movement. All that is
left was to initiate that movement," explains Rubia van den Brand,
contributing author to the study.
The
innate intelligence of the spinal column
In 2009, Courtine already reported on restoring movement, albeit
involuntary. He discovered that a stimulated rat spinal column -- physically
isolated from the brain from the lesion down -- developed in a surprising way:
It started taking over the task of modulating leg movement, allowing previously
paralyzed animals to walk over treadmills. These experiments revealed that the
movement of the treadmill created sensory feedback that initiated walking --
the innate intelligence of the spinal column took over, and walking essentially
occurred without any input from the rat's actual brain. This surprised the
researchers and led them to believe that only a very weak signal from the brain
was needed for the animals to initiate movement of their own volition.
To test this theory, Courtine replaced the treadmill with a device
that vertically supported the subjects, a mechanical harness did not facilitate
forward movement and only came into play when they lost balance, giving them
the impression of having a healthy and working spinal column. This encouraged
the rats to will themselves toward a chocolate reward on the other end of the
platform. "What they deemed willpower-based training translated into a
fourfold increase in nerve fibers throughout the brain and spine -- a regrowth
that proves the tremendous potential for neuroplasticity even after severe
central nervous system injury," says Janine Heutschi, co-author in the
study.
First
human rehabilitation on the horizon
Courtine calls this regrowth "new ontogeny," a sort of
duplication of an infant's growth phase. The researchers found that the newly
formed fibers bypassed the original spinal lesion and allowed signals from the
brain to reach the electrochemically-awakened spine. And the signal was
sufficiently strong to initiate movement over ground -- without the treadmill
-- meaning the rats began to walk voluntarily towards the reward, entirely
supporting their own weight with their hind legs.
"This is
the world-cup of neurorehabilitation," exclaims Courtine. "Our rats
have become athletes when just weeks before they were completely paralyzed. I
am talking about 100% recuperation of voluntary movement."
In principle,
the radical reaction of the rat spinal cord to treatment offers reason to
believe that people with spinal cord injury will soon have some options on the
horizon. Courtine is optimistic that human, phase-two trials will begin in a
year or two at Balgrist University Hospital Spinal Cord Injury Centre in
Zurich, Switzerland. Meanwhile, researchers at EPFL are coordinating a nine million
Euro project called NeuWalk that aims at designing a fully operative spinal
neuroprosthetic system, much like the one used here with rats, for implanting
into humans.
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