ALZHEIMER'S DISEASE

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.