A fascinating, yet not fully developed technology of using light to modify the DNA of neurons in living organisms has just been employed as a painkiller in mice, paving the way for very effective and inexpensive cure for pains in humans.
Optogenetics is a very high-tech method for controlling nerve cells, and although around for a few years, continues to yield amazing discoveries. People’s fascination with it lies in its ability to be used for controlling nerve behavior in living things with surgical precision.
Having just performed new tests on mice, this time around, researchers at Stanford University in California hope that removing or blocking pain will soon be as easy as pressing a bright flashlight to the affected area. They partnered up with a company called Circuit Therapeutics – a leader in optogenetics – and published their findings in the journal Nature Biotechnology.
Michael Keplitt is a neurosurgeon and chief scientific officer at
Circuit Therapeutics, a three-year-old California-based biotech
startup that in a short while has already taken the lead in
propelling optogenetics to stardom.
“Patients could be given their own ability to create a pain
block on demand,” he wrote of the technology that could be
used for directly controlling nerve behavior. The technique has
been around for nine years in one form or another.
When first conceived by Karl Deisseroth, one of the authors of
the study and the creator of Circuit Therapeutics, the technique
was used to inflict and take away fear in mice.
A lot of optogenetics experiments work simply by shining a light
onto the area where the pain is, blocking the neurons from
firing. But an even more daring method has been tested as well,
where a tiny fiber-optic cable is used to shine a ray directly
into the brain of an animal.
In future, the company also hopes to develop that further;
however, for the time being, working on areas outside the brain
is more practical and easy. The reason for this is that the nerve
endings affected by the light are located incredibly close to the
surface of the skin and therefore take no effort at all to reach.
If the idea that using a simple flashlight-type device to cure
pain sounds crazy, it’s because the very perception of pain is
different from reality. “Pain is a perception. So the idea is
to stop the perception of it,” Kaplitt said.
The study the two teams undertook worked by embedding
light-sensitive molecules under the thin upper layer beneath the
skin of mice, right into the nerve endings. They were then placed
in their own little plexiglass chambers, and the experiment
began.
A blue light would be shone through the floor, and it would cause
pain: mice would either cry out or lick their paws incessantly to
alleviate it. A different type of light was then used to elicit
the opposite reaction by blocking the neurons from firing. When
that yellow light was shone onto them, they either felt no pain
or were very slow to react to it.
Kaplitt believes the study to be a resounding success, because
“it raises two prospects. One is that you can essentially
turn on and off nerves causing pain at will. The other is that
they illuminated the animal from the outside and still got the
effect.”
And the advantages don’t stop there. The economy here could be
very substantial, as around $635 billion a year is being spent on
health in the US at this time, according to MIT Technology
Review, while the medicine used to kill off pain isn’t always a
guarantee, at times leading to bad side effects as well as
addiction.
Scientists are optimistic, even though progress aimed at
pinpointing where exactly to shine the light and how much of it,
is slow at the moment. They predict at least 10 years of studies
before a workable solution can be manufactured.
However, companies such as Google and people from MIT, which
helped in the creation of optogenetics nine years ago, aren’t
resting on their laurels either. Like Circuit Therapeutics, they
are engaged in pooling efforts together to create their own
optogenetics-inspired pain killer. Ed Boyden of MIT has just
founded Eos Neuroscience aimed at doing just that.