Why understanding about Alzheimer's
disease is important?
Alzheimer's disease is a form of
dementia which is an umbrella term for a set of symptoms related to
memory loss and logical thinking impairments, among other things.
Alzheimer is unique because it affects 5.4 million Americans and is
the 6th leading cause of death in the US. That means that
it affects 1 out of 10 Americans over the age of 65. No one is exempt
from the disease and there is no way to actively prevent it. Since
the year 2000 the death rates of other diseases such as HIV, stroke
and heart disease have decreased, but the death rate of Alzheimer's
disease has grown by 66%. The last reason why understanding about
Alzheimer's is important because there is no known cure. There are
treatments that will slow the progression of the disease but none
that will stop it.
What is Alzheimer's disease?
Alzheimer's is a disease that affects
the brain in many of it's critical functions. It's difficult to
diagnose because it may sometimes be confused with just “growing
old” or symptoms of too much stress. However, Alzheimer's disease
is a very real condition with biological impairments. Because of the
way it spreads in the brain, Alzheimer's disease is categorized in
separate stages.
It originates in the hippocampus which is the area
in the brain in charge of forming new memories. Alzheimer's patients
have difficulty recalling events from a few hours or days ago. The
disease then spreads to the part of the brain where language is
processed. Thus it becomes harder to recall “the right word”.
Next it spreads to the part of the brain where logical thinking takes
place. So, it becomes harder to solve problems where complex thought
is required. It then progresses to the part of the brain where
emotions are regulated, therefore it becomes difficult to
respond/control to emotional circumstances appropriately. Next is the
part of the brain where senses are perceived, so patient may start to
hallucinate. After that it spreads to the part of the brain where the
persons most oldest memories are stored. Late stage of Alzheimer's
disease is where balance and coordination of a person deteriorates
causes them to be wheelchair bound. The last stage is where the
persons breathing and heart regulation is affected, ultimately
causing death. All these stages take place in about between 8-10
years time, sometimes more or less depending on the individual.
How Alzheimer's disease takes place?
Research has shown that Alzheimer's
disease happens when two unusual substances are produced by the
brain. These substances are know as Plaques and Tangles.
Cell membranes of neurons process
proteins. Plaques are formed when proteins in the neurons cell
membrane are processed abnormally. In a normal neuron an enzyme
known as alpha-secretase cut apart a protein called APP
(Amyloid Precursor Protein), a normal and in fact vital substance
needed for the cell. A second enzyme known as gamma-secretase
cuts another part of APP. The two released fragments from these
enzymes are normal. In patients suffering from Alzheimer's disease
the first cut of APP is made by an enzyme called beta-secretase
instead of alpha-secretase, this combined with the second cut
of APP by gamma-secretase releases a part of APP known as beta
amyloids. The beta amyloids clump together and become bigger and
bigger until they form structures known as plaques. Plaques are too
big in size and are insoluble in cerebral fluid. Plaques attach
themselves to the neuron membrane. This triggers the brain to release
powerful chemicals, however these powerful chemicals backfire because
they set of a series of reactions that destroy the neuron.
Tangles are formed inside the neurons
in contrast to plaques which are formed outside the neurons. Tangles
are made when a protein known as Tau is modified inside a neuron. Tau
is a protein that keeps together an organelle inside neuron known as
microtubules. Microtubules are tube like strands inside the neuron
that transport important materials to all parts of the neuron. In
Alzheimer's disease tau protein becomes hyperphosphorylated
(Phosphorylation
is the process of addition of phosphate groups),
which means that an extra phosphate group cannot be added to
tau. This causes the tau to separate from the microtubules causing
them to fall apart. These abnormal tau bond together inside of the
neuron and makes structures know as “tangles”, which disrupts the
normal functioning of neurons.
