Home' Southern Health News : October 2014 Contents The research team, led by Associate Professor
Nick Spencer, is closing in on a way to
supress pain arising from conditions such
as neuropathic pain, inoperable tumours or
terminal cancers that trigger activation of
pain receptors at specific sites in the body.
The innovation is three years in the making and
follows work to unlock one of the world's greatest
medical mysteries -- the exact location of all of
the body's nerve endings that detect pain from
different internal organs and how these pain
receptors are activated.
"Current therapies for pain relief are very poor
because they are incredibly non-specific," he said.
"If we don't know where the nerve endings are
that detect pain and we don't know how they're
activated, it is very difficult to develop selective
therapies to prevent their activation.
"Today if someone has severe pain they will
probably be given an opioid like morphine
that is very good at relieving pain but
has a whole range of side effects.
"You can get sedated, addicted, build tolerance,
suffer from withdrawal and constipation,
you can't drive a vehicle or think straight
-- your whole body is affected by the pain
medication -- that's the big problem."
Associate Professor Spencer conducted the
mapping on animal models using a tracing
technique which involves injecting a small
volume of liquid dye into a specific part of the
nervous system, containing all of the body's
nerve cells that detect painful stimuli.
The dye is then drawn up by the nerve axons and
transported to their endings within internal organs
such as the bladder, lungs or uterus. This allows
the team to directly visualise where all the nerve
endings that detect painful stimuli are actually
located, without also labelling all the other classes
of nerves in the body.
From here, Associate Professor Spencer and
his team devised a technique which involves
FMC Medical Scientist Associate
Professor Nick Spencer
injecting a harmless virus -- containing a
specific molecule -- into the organ or site
where the pain is originating from. The virus is
then transported back up into the spinal cord
where the molecule selectively shuts down the
development of a particular sodium channel
which is essential for pain perception.
"It was based on the idea that pain information is
detected by specific classes of sensory neurons that
lie just near the spinal cord and by targeting only
these neurons, we could shut down only those
neurons that detect the painful stimuli," he said.
"This is the latest technology, very much like gene
therapy, where you can deliver a gene or silence
a gene to enhance the behaviour or suppress the
behaviour of particular cells or organs."
In his laboratory experiments so far on animal
models, Associate Professor Spencer has
reduced pain by about 75 per cent from
a specific organ, the gastrointestinal tract,
without affecting other organs in the body.
"Turning pain off is not instant, it can take
days to weeks, but the big
advantage is that the pain
can be suppressed for long
periods without the classic
side effects of current
pain therapies," he said.
"We can supress pain
for months to years,
so it's very exciting.
"Often with long term
chronic, severe neuropathic
pain, for example, there is
damage that is life long.
If you fall off a ladder you
can damage spinal nerve
routes that lead to lifelong neuropathic pain, which
is basically incurable. There is no point in that pain
in a patient for their entire life. We know there is
damage, so in that case there is huge demand to
supress pain from the target site without opioids."
The first phase of experiments involved suppressing
incurable pain linked to the stomach, small
intestine and large intestine. However, Associate
Professor Spencer said it was a technique
which could be applied to all internal organs.
"We are very excited by our new technique
and what it tells the community," he said.
"I would envisage myself spending the next
decade on this, because there's so little known
and the ramifications could be so substantial."
In 2013 Associate Professor Spencer was
awarded more than $900,000 in funding by
the National Health and Medical Research
Council to conduct the research.
Major breakthrough for chronic pain su erers
BY KYLA GOODFELLOW
In a major potential breakthrough for chronic pain su erers, Flinders Medical Centre researchers have developed a new
technique to switch o pain directly at the source, potentially eliminating the need for highly-addictive painkillers such as
morphine, that have so many side e ects in other parts of the body.
SOUTHERN HEALTH NEWS / OCTOBER 2014 / 3
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