Pain is the most unpleasant type of sensory response
received by human brain and is often more or less associated with an under
lying condition which tends to inflict some sort of physical damage to body
tissues, the very sensation pushes human conscience to develop strategy to
protect its damage body parts for enabling proper healing and recovering full
working capacity of damaged tissues. But this very sensation has a darker
aspect, in certain diseases pain to be endured is too much for any human being
and this often leads to decision relating to ending one’s life. Another key
issue exists in form of chronic pain where a person consistently feels pain for
months or even years despite of recovering from original cause in form of an
injury or a disease, according to an estimate ranging from 19-50% of global population
experiences chronic pain for a greater part of their life and in response
recommended opioids often produce numerous side effects which leads to
development of some diseases or may cause conditions of substance abuse. Now
this overall situation demands a solution one that can suppress or cure pain in
certain medical cases and prolongs life span with a possibility of some cure in
near future. In this regard the CRISPR based genome editing is now proving to
be a ray of hope at the very end of a dark tunnel.
The pain tunnel
Now the brain experiences sensation of pain upon
receiving some sort of stimulus like touching a hot pan, getting some sort of
cut and so on, this triggers a series of electrical signal inside human nervous
system which convey signals of pain. Inside body the nervous system is made up
of a neurons and each neuron has small pore like openings present on its
surface called the ion channels. These channels consistently open and close to
allow neuro-chemical communication in nervous system and among these channels
is the sodium Na v1.7 channel which allows pain signalling with influx of
sodium ions inside neurons. Although there are many studies which have
suggested that a sodium channel called Na v1.7 could play a central part in
chronic pain, but in various cases when people have mutations in the gene
coding for this channel, they either experience extreme, constant pain, or
can’t feel any pain at all. Scientist have been trying to block these Na v1.7 channels
by using certain small-molecule drugs and antibodies, but they often struggled
because these therapies also interact with structurally similar sodium channels
in the body leading to severe complications, in order to deal with this issue
and find a cure for this pain by manipulating ion channels researcher from University
of California, San Diego lead by PhD candidate Ana Moreno decided to harness
power of modified version of CRISPR/CAS9 molecule which tends to locate gene with precision
and modify its function without any off target effects.
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| Pain signals are transmitted to the brain through neurons similar to these in the spinal cord |
CRISPR Ray of
Hope:
the team utilized a variant of CAS9 called the dcas9
(de natured CAS9) in which the molecule perform
all standard functions from gene targeting to binding but only the cleavage
function is absent, the molecule is then attached with a repressor molecule which
prevent expression of that gene, the team encoded this dCAS9 for Na v1.7 gene
in order to suppress its expression and reduce pain sensation. Molecule was
then injected in to a mice followed by chronic pain stimulus with chemotherapy
and results show high tolerance of pain in mice for up to 44 weeks, similar
level of tolerance was also observed in mice that previously had issues
involving chronic pain. The dCAS9 molecule only binds with certain gene and prevent
its expression for a certain time this also prevents permanent changes in DNA
and revives the ability to feel pain once the baseline cause of chronic pain
has been resolved bringing back life to normal.
Senior neuro-scientist Sulayman Dib-Hajj, at Yale
University describe that although this is still far from human trials but it is
a great and highly successful start with
nearly 44 week relief this can revolutionize the entire treatment procedures for
various painful diseases.
Conclusion:
Cure of pain for a certain time frame can provide
various patients a temporary necessary relief from serious pain experienced during
treatment procedure like for cancer treatments and so on. Also it can provide
number of options for athletes to soldiers as for how they really want to deal with
their injury and what level of compromise they would be ready to make with
their profession for healing a certain injury. This research also provide a
possible hope for also recreating pain sensation by certain degree of
reengineering in case of certain disease related to pain insensitivity which
often lead to serious life threatening injury and loss of organs in patients
having such conditions.
