Alzheimer's: The Unsolved Mystery
Absentmindedness, with questions having to be repeated, trouble following conversations, or remembering people's names, sound familiar? These are classic early stage symptoms of Alzheimer's.
Alzheimer's is a type of dementia in which parts of the brain stop working, causing memory loss, and instability in judgement, reasoning and emotions. Dementia, such as Alzheimer's is usually more frequent in elderly people. Approximately 15 percent of people who are over 65 will develop some form of dementia; by the age of 85 that percentage increases by at least 35 percent. Alzheimer's is the
…show more content…
These deposits gather in the spaces between the nerve cells, causing the neurons to look swollen and mutated. The clusters of protein usually accompanied by reactive inflammatory cells, which might degrade and remove damaged neurons. These plaques are specific to Alzheimer's patients and appear long before the tangles do. The main component of these plaques are peptides made up of 40-42 amino acids, the BAPP protein. However BAPP remains a mystery. Researchers know that many different cells produce BAPP and that it be in between 695-770 amino acids long. The protein runs through the outer membrane with a short piece cutting into the cell and a longer piece sticking into the extracellular space. The B-amyloid peptide is cut out of the section of BAPP that spans the cell membrane. Scientists discovered that BAPP is cut in two different ways. One way the proteins is first cleaved by an enzyme called alpha-secretase. Then it is cut by another putative enzyme, gamma-secretase. This sequence of cuts creates a harmless peptide fragment.
The second way BAPP is clipped by beta-secretase. One of the resulting pieces C99-BAPP is then snipped by gamma-secretase and the B-amyloid peptide is born, some of which may have two extra amino acids. This slightly longer form is the one that gives rise to plaques and that it has a direct toxic effect on neurons. First, the peptide seems to disrupt