How Does Alzheimer’s Disease Affect the Brain? Alzheimer's Disease research suggests the following pathophysiology:
How Does Alzheimer’s Disease Affect the Brain?
Alzheimer’s disease is a progressive neurodegenerative disorder that profoundly impacts the brain resulting in cognitive decline and memory loss, symptoms of dementia. Research shows that damage in the brain, due to Alzheimer's disease, happens at various levels, from cells to entire regions of this organ.
Buildup of deposits in the brain of amyloid-beta and tau proteins for those suffering from Alzheimer's disease:
First described by the research of Dr. Alois Alzheimer more than 120 years ago, the brain presents accumulation of materials inside and outside of the nerve cells. About 80 years later, through further developments in scientific research, we discovered that these are the end-products of two proteins: amyloid-beta and tau which form the amyloid plaques and tau tangles, respectively. Smaller forms of these proteins, called oligomers, may begin damaging the brain long before they form deposits and any symptoms appear.
Brain shrinkage in Alzheimer's patients:
Dr. Alzheimer also first discovered through his scientific research that these patients also experience a significant amount of brain shrinkage because of the damage and resulting in degeneration /death/ loss of entire clusters of cells in various areas of this organ. In average this could result in 30-40% less brain tissue.
Inflammation of the brain in Alzheimer's patients:
Inflammation is an important part of the immune defense system response for the brain and body in general. With aging, a low-grade chronic inflammation can develop —a phenomenon also called “inflammaging”. This process can make the brain more vulnerable to various factors, especially if there is a history of other inflammatory events like a traumatic brain injury. It is thought that Alzheimer's disease-related damage to brain cells causes a significant increase in inflammation— a double-edged sword that can cause even further damage to the brain.
Reduction in Blood Flow in Alzheimer's patients:
The blood is the vehicle through which essential components and nutrients (oxygen and sugar) reach to the brain supporting its function. While, even with healthy aging, there is some reduction in blood flow rate, for those diagnosed with Alzheimer’s disease, the reduction in blood flow to the brain is higher and, as a result, can negatively impact basic brain activities from thinking to memory.
Low Fuel or glucose levels: the main food for the brain:
Sugar (glucose) is the main food for the brain, like the fuel for an engine it is essential for its normal function. In Alzheimer’s, for mechanisms not totally clear yet the brain is not able to use it resulting in a progressive condition of “starvation” for the cells. This then results in reduced general brain activity with consequences for important functions like memory and thinking.
Waste Removal in the brain of Alzheimer's patients:
Cerebrospinal fluid flows throughout and around the brain and is involved in a process called lymphatic clearance, meant to help the brain to remove waste throughout our life. If the system does not work properly less and less material is cleared out, as consequence the brain will accumulate (amyloid-beta and tau proteins). Studies in Alzheimer's research are ongoing to determine which are the factors that can influence waste removal in Alzheimer’s disease. Among them, recent Alzheimer's developments pointed to the nerve cell digestive system called autophagy, which with aging can become impaired and contribute to this phenomenon.
In summary, Alzheimer’s disease could be considered in some way as an extreme version of normal brain aging, since many of the pathological features that characterize the disease are also present in normal aging, although at a much smaller scale. In normal aging of the brain there is expected to be some a reduction in volume of the brain, accumulation of unwanted material, insufficient food/fuel, removing waste in the brain, and inflammation.
For broad information and resources related to Alzheimer’s disease, click here to visit Alzheimer’s Association website. Or connect with other great resources, National Institute on Aging or American Federation for Aging Research
If you would like to learn more:
Domenico Praticò, MD, holds the position of the Scott Richards North Star Charitable Foundation Chair for Alzheimer’s Research and serves as a Professor and the Founding Director at the Alzheimer’s Center at Temple, as well as a Professor of Neural Sciences at Lewis Katz School of Medicine at Temple University.
For more information on the research conducted by Dr. Domenico Pratico, please visit this link.
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Stay updated with the work happening at Dr. Domenico Pratico's lab by visiting the Pratico Lab website.
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