THE
GLYMPHATIC SYSTEM
Compiled,Collected,Edited
and Presented by:-
JAGANNATHAN
Dear
friends,
Glymphatic
System is a recent and important concept which may be the door to guide us to
many Neuralogical issues.
Please
share your vies and Comments
Many of us are familiar
with the lymphatic system; it performs a number of roles, one of which is
clearing metabolic waste from the interstitial space.
However, the central nervous system , which
comprising of the brain and spinal cord, does not have any true lymphatic vessels .In a way the GLYMPHATIC SYSTEM is the Lymphatics of the brain
Because the CNS is
highly active, metabolic waste can build up quickly.
The CNS is also very
sensitive to fluctuations in its environment, so the body needs to remove
cellular wastes somehow, and that’s where the glymphatic system comes in.
Before the discovery of
this brain-based wastage disposal system, scientists believed that each
individual cell handled its own metabolic wastage clearance.
If the cellular system
became overloaded or slowed down as we aged, metabolic wastage would build up between the cells. This wastage
includes products such as beta-amyloid — the protein associated with Alzheimer’s disease.
The name GLYMPHATIC SYSTEM is a reference to the glial cells, which are
vital to this waste clearance system.
Glial cells are given
relatively little coverage, compared with neurons, in the brain. They were
long considered little more than lowly support cells, but are now held in
higher regard.
Glia protect, nourish,
and insulate neurons. They also play a role in the immune system and, as we now
know, the glymphatic system.
In particular, a type
of glial cell known as Astroglia are important. receptors, called
aquaporin-4 channels. These cells allow cerebrospinal fluid to move into the
CNS, setting up a current that shunts fluid through the system.
CSF surrounds the CNS,
providing it with mechanical and immunological protection, among other things.
The
glymphatic system, which runs parallel to arteries, also improves the pulsing
of blood in circulation to help keep things moving.
As the blood vessels
expand rhythmically, they drive the exchange of compounds between the
interstitial space and the CSF.
The glymphatic system
connects with the lymphatic system of the rest of the body at the dura,
membrane of connective tissue that covers the CNS.
It has been found in
animal experiments that the glymphatic system was most busy as the animals
slept. They showed that the volume of interstitial space increased by 60% while the mice were
sleeping.
This volume increase
also boosted the exchange of CSF and interstitial fluid, speeding up the
removal of amyloid. They concluded that:
“The restorative
function of sleep may be a consequence of the enhanced removal of potentially
neurotoxic waste products that accumulate in the awake stage
HIGH
BLOOD PRESSURE
. The researchers have
recently studied at the impact of high blood pressure on the function of the
glymphatic system.
Over time, high blood
pressure causes blood vessels to lose their elasticity, becoming increasingly
stiff. Because the regular pulsation of arterial walls drives the glymphatic
system, this stiffening impedes its function and it prevented it from
efficiently clearing of large molecules
in the brain, such as beta-amyloid.
This finding might help
explain why scientists have found links between
elevated blood
pressure and
cognitive decline and dementia.
Parkinson’s disease is one condition
characterized by the buildup of protein in the brain. In this case, the protein
is Alpha-synuclein.
In Parkinson’s disease,
there is disruption in the dopamine pathways of the brain. These pathways play
an important role in sleep-wake cycles and circadian rhythms; therefore, people with Parkinson’s often experience sleep disturbances. the disrupted sleep patterns could hinder the glymphatic removal of
debris, including alpha-synuclein, helping it to accumalate in the brain.
Chronic traumatic
encephalopathy results from repeated blows to the head; it used to be called
“punch-drunk” syndrome because it occurs in boxers.
Brain injuries may
interfere with glymphatic drainage.
Symptoms can include
memory loss, mood changes, confusion, and cognitive decline.
It is believed that
disruptions to the glymphatic system caused by brain trauma may increase the
risk of developing chronic traumatic encephalopathy.
,Difficulties with
sleep onset and maintenance are among the most commonly reported symptoms of
Brain Trauma
As we have seen, this
interferes with the glymphatic clearance of proteins from the interstitial
space during sleep.
At the same time, these
types of injury can cause the relocation of aquaporin-4 channels — those
important receptors on astroglia that are vital for glymphatic clearance — into
a position that hinders the removal of waste proteins from the interstitial
space..
Beyond a possible role
in neurological conditions, some researchers have investigated how disturbances
in the glymphatic system may be involved in the cognitive symptoms of diabetes.
Scientists have shown
that diabetes can impact an influence on cognitive functions, both early in the
disease’s
progression and further down the line.
As we age, a certain
level of cognitive decline is almost inevitable. There is a wide range of
factors involved, and some scientists believe that the glymphatic system could
play a role.
A study in 2014
investigated the efficiency of mice’s glymphatic systems as they aged; the
authors found a “dramatic decline in the efficiency.”
It has been recently
found that reduced activity in the system as we age might “contribute
to the accumulation of misfolded and hyperphosphorylated proteins,” increasing
the risk of neurodegenerative diseases and, perhaps, exacerbating cognitive
dysfunction.
We still know comparatively little
about the glymphatic system. However, because it cleanses our most sensitive
and complex organ, it is likely to influence our overall health to some degree.
The glymphatic system
might not contain the answers to all of our questions about neurodegenerative
diseases and beyond, but it could hold the key to some interesting new
perspectives.
Thank
you
JAGANNATHAN
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