Why does Alzheimer's Disease happen? The truth is that nobody knows for certain but there is pretty good evidence that things like genetics, poor diets and lifestyle choices (eg smoking/exercise) in one way or another contribute. The real fact is that the single biggest risk factor for Alzheimer's is age. Alzheimer's disease is quite simply a disease of aging. But that doesn't mean that just because you get old you have to develop Alzheimer's disease. There are ways to slow, stop or even reverse this disease. First it requires understanding the Alzheimer's disease process (Its just that drug companies haven't found a way to make us pay huge amounts for it yet).
So lets start at the big organ in our heads "the brain". Although it looks all the same not all parts of the brain are alike. Different areas do different things. At the back is the part that deals with sight. On the top left and right are the parts that control touch sensation and body movement and going through the center of our brains down to the bottom is and area called the hippocampus. Why is this area important? It is involved with memory formation and recall and is the area where Alzheimer's disease wreaks the most damage. This is why Alzheimer's disease shows up as severe deficits of a person memory.
What happens to the hippocampus in Alzheimer's disease? In simple terms parts of it begin to die and become inactive. Like the rest of the brain the hippocampus is made up of billions of microscopic cells called neuron and a few other helper cells. In a normal hippocampus these neurons form connections and circuits between one another and transmit signals around these circuits to form or recall memories. In Alzheimer's however the neurons get sick and become damaged and eventually die. When these circuits fall apart so does the ability to form or recall memories. Now we delve deeper into the mystery to uncover why the neurons die?
A neuron by itself is like a tiny country. It has systems to turn food into energy, transport molecules and energy around it, even gatekeepers to regulate cell exit and entry. In Alzheimer's disease some of these systems go haywire. They go haywire because of the formation of what is called a beta-amyloid plaque. Essentially It is the buildup of massive amounts of beta-amyloid plaques in and around neurons that set off a chain reaction of destructive events that result in neuron death. By the way when neurons die generally they are not replaced, so essentially what's in you head right now if all you've got for the rest of your life. This is why Alzheimer's disease is so devastating.
Why do beta-amyloid plaques form? We still don't know for sure but it does appear that excessive oxidative damage and the presence of free metal ions such as copper and particularly iron are involved. Somehow oxidative stress leads to an increase in the beta-amyloid proteins while both oxidative stress and metal ions are required for the beta-amyloid to clump together and form plaques. There we go, already three molecular targets for combating Alzheimer's disease. Reduce beta-amyloid, reduce oxidative stress and reduce metal ion levels. This however is not the whole story.
It is also useful to know how the beta-amyloid plaques lead to neuron death. After a beta-amyloid plaque forms it has the ability to generate more reactive oxygen species (ROS, also called free radicals). These ROS float around inside the neuron causing damage to anything they bump into. This is the same process that causes metal to corrode. When enough of this corrosion occurs critical cellular systems break down. Two of these are energy production and transportation. Imagine what would happen to our economies if both transport and energy systems broke down simultaneously. It would be chaos and it is no different in the neuron. With these systems incapacitated the neuron can do one of three things.
It clings onto life unable to contribute any productive functions to the brain as a whole.
It programs itself for controlled suicide called apoptosis.
It falls to pieces
All of these are bad but some are worse than others. It is possible to re-establish neuron function from severely damaged cells so in the first case there is hope. In scenario number two there is little mess but we lose a neuron forever. Scenario three is the most destructive. It spills its contents over other cells and neurons thereby exposing them to dangerous molecules including ROS and beta-amyloid plaques. To add insult to injury their spilled contents alerts the immune cells in the brain. The job of these cells is to look out for foreign invaders but they are indiscriminant. They are tricked into believing an invasion is imminent and nuke the entire area with more damaging chemicals. Most people know this process as inflammation.
What does all this result in? More damage to neurons resulting in more neurons falling apart, killing themselves or just becoming vegetables. And thus the cycle continues until there are no neurons left to die or the person themselves dies. I know this is a horrible disease but if you can understand the molecular causes you can find targets to at least slow it down. Here are the last few. Reduce cellular oxidative stress, protect critical systems such as energy production and transport, reduce inflammatory reactions and reprogram neurons to remain alive and return to function.
Now i can here people say "but how do we exploit these targets?" Well believe it or not a lot of good science shows that there are foods, herbs, supplements and other basic techniques that can influence every single Alzheimer's disease target I presented to you. In future posts i will cover some of this science in the hope you or someone you know can benefit from it. One final thought. Do you know which of the targets in this post current Alzheimer's drugs act on? Not a single one.
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