Cannabis – The Ultimate in Neuroprotection
By Mary Biles
Earlier this year we saw the announcement that THCa, another
molecule found in the cannabis plant, has neuroprotective effects. Apart from
flying in the face of the belief that cannabis damages brain cells, why should
we care whether something is neuroprotective or not? The death of brain cells
is a natural part of the ageing process. Cells die off and the body is also
capable of making new ones through neurogenesis. But the older we get, the more
susceptible we become to ‘inappropriate cell death’ through traumatic injury,
environmental toxins, cardiovascular disorders, infectious agents, or genetic
diseases. That’s why scientists are researching neuroprotective drugs to limit
the damage caused to brain cells after acute events such as strokes, to slow down
the progression of neurodegenerative diseases, and to even prevent unnecessary
cell death from happening in the first place. Different molecules in the
cannabis plant – called cannabinoids – are being investigated for their
neuroprotective action, but in order to understand why, let’s first take a look
at why brain cells die off in the first place.
What causes brain cell death?
1. Oxidative stress
Just being alive and burning energy creates oxidative stress
– damage caused by free radicals which the body cannot remove. Dr Joseph
Mercola describes the result a sort of ‘biological rusting’ where there is too
much oxygen in our tissues leading to a host of age related diseases such as
chronic inflammation, cancer, neurodegenerative diseases like Alzheimer’s and
Parkinson’s, autoimmune conditions, heart disease, and strokes.
2. Excitotoxicity
Too much activity in the brain can cause neurons to die off.
This is generally attributed to over stimulation by the neurotransmitter
glutamate, a situation commonly found in many neurodegenerative diseases and
following strokes.
3. Inflammatory changes
Inflammation is usually a sign of the immune system going
about its job of cleaning up after an injury or dealing with a foreign invasion
such as a bacteria or a virus. However, too much inflammation can cause cell
death. According to Gary Wenk, PhD, professor of neuroscience, immunology and
medical genetics at Ohio State University, ‘PET imaging studies of humans have
shown that after age thirty the brain gradually displays increasing evidence of
inflammation. With advancing age, brain inflammation continues to worsen
leading to a decline in the production of new neurons, called neurogenesis,
that are important for making new memories’.
4. Iron accumulation
Scientists believe excess iron in the brain plays a role in
degenerative diseases such as Alzheimer’s, Parkinson’s and amyotrophic lateral
sclerosis (ALS). This iron build-up is may be part of the cycle of
excitotoxicity and brain cell death.
5. Brain proteins
While much is still to be learned about diseases such as
Alzheimer’s, scientists now know that a common factor is the build up of
proteins called beta-amyloid which form into plaques. It is thought these
plaques may block cell-to-cell signalling at synapses and create excess
inflammation as the immune system kicks in to attack the affected cells. A
protein called tumor necrosis factor (TNF) has also been found present in
neurodegenerative diseases, and is further associated with excitotoxicity and
high levels of glutamate. With all these pathological changes occurring in
conditions related to a degeneration in the brain, it would make sense that
scientists are looking for a pharmaceutical magic bullet that can address each
and every one of them. But what if they didn’t have to look any further than
the cannabis plant?
THCA an exciting neuroprotective prospective?
Let’s get back to the most recent discovery regarding the
neuroprotective qualities of THCA. First things first, THCA is the acid
precursor of THC, the most well known and generally abundant compound in
cannabis. If you picked the leaves and flowers straight off a cannabis plant,
you’d find barely any THC, what you’d get instead is plenty of THCA. That’s
because in order to become THC, THCA must go through some sort of heat process
or decarboxylation. Comparatively little research has been done on THCA.
However, scientists do know is that it has no psychoactive effect and appears
to be anti-inflammatory, anti-emetic and shows some anecdotal success in
reducing seizures.
This latest research adds neuroprotection to the list. It
studied the effect of the raw cannabinoid on cells and mice modified to elicit
the symptoms of Huntington’s disease. In the cell cultures they found THCA
caused an increase in mitochondrial mass as well as reducing cell toxicity,
while in the mice, THCA improved their Huntington’s related restricted
movement, prevented striatal degeneration and reduced the inflammation caused
by the disease. Scientists noticed that these effects were elicited
independently of the endocannabinoid system, concluding:
“THCA shows potent
neuroprotective activity, worth consideration for the treatment of Huntington’s
Disease and possibly other neurodegenerative and neuroinflammatory diseases.” While
this further strengthens the growing health trend towards consuming raw
cannabis, in a laboratory setting acid cannabinoids can be quite hard to work
with due to their instability and transformation into their decarboxylated
versions.
What about the other cannabinoids?
One of the great mystifying contradictions in the world of
medical cannabis is how on the one hand it is a schedule 1 banned substance
deemed bereft of any therapeutic value and yet the United States Federal
Government holds a patent for the plant’s principal cannabinoids based on their
antioxidant and neuroprotective effects. United States Patent US6630507 states
how cannabinoids are:
“… useful in the
treatment and prophylaxis of wide variety of oxidation associated diseases,
such as ischemic, age-related, inflammatory and autoimmune diseases. The
cannabinoids are found to have particular application as neuroprotectants, for
example in limiting neurological damage following ischemic insults, such as
stroke and trauma, or in the treatment of neurodegenerative diseases, such as
Alzheimer’s disease, Parkinson’s disease and HIV dementia.” Contradiction aside,
this public proclamation based on obvious vested financial interests is hardly
surprising when one considers that cannabinoids like THC and CBD provide a
potentially unique multipronged approach to preventing, protecting and limiting
the damage caused by strokes and neurodegenerative disease.
One of the key reasons being that THC and CBD as considered
powerful antioxidants, on a par with vitamins C and E. Studies have found that
cannabinoids can reduce the excitotoxicity associated with too much glutamate
production as well as protecting brain cells against the damage caused by
excessive iron.
Not only that, but cannabinoids have been found to promote
the holy grail of the healthy ageing brain, neurogenesis, or the growth of new
brain cells. Research has shown the administration of plant cannabinoids
promoted hippocampal neurogenesis – new cell growth in the region of the brain
associated both with memory and learning.
Cannabinoids have also shown promise in reducing the
neuro-inflammation found in rodents injected with the amyloid beta protein
which as discussed before can lead to neuronal cell death in Alzheimer’s.
And finally, CBD in particular is thought to limit the
damage caused to the brain after a stroke by blocking the neurotransmitter,
glutamate. To put this into perspective, so far most neuroprotective drugs
under research are based on single therapeutic targets. They aim to protect the
brain by doing one thing at a time.
Explains Javier Fernandez Ruiz, Professor of Molecular
Biology specialising in neurodegenerative diseases at the Complutense
University in Madrid:
“This is one of
the great advantages of cannabinoids. They have a very wide spectrum and are
extremely varied compared to other neuroprotective agents that have been
researched until now. These have consisted of anti-excitotoxins to improve the
glutamate homeostasis, antioxidants or anti-inflammatories. But what we know is
that the various stimuli that cause cell death work together. In other words,
where there is excitotoxicity there is oxidative stress, the proteins become
oxidized, they lose their function, they form together to make plaques, which
causes an inflammatory response. “We
are not going to halt neurodegenerative diseases unless we have neuroprotective
strategies that work together by reducing inflammation while at the same time
being antioxidants, inducing autophagy in order to eliminate the protein build
up, and returning the glutamate levels to normal. “This is something that cannabinoids can
do, either one cannabinoid or a number of cannabinoids together.”
So far, the field of neuroprotective pharmacological drugs
is in its infancy, both in medical cannabis derivative research and further
afield. However, the race is on to see who can crack the puzzle and find the
combination of cannabinoids that will not only slow down neurodegenerative
disease, but maybe even prevent us from getting them in the first place.
About the author:
Mary Biles is a British freelance writer, blogger and
wandering spirit, mostly based in the Andalusian capital of Seville, Southern
Spain. She is passionate about the healing potential of cannabis and currently
writes for CBD oil innovators Endoca, as well as her own blog, I Know a Little
Place in Seville.
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