Alzheimer’s

Information

With 60 to 70%, Alzheimer’s disease is the most frequent cause of dementia in old age. Its prevalence doubles about every five years from the age of 65. 30% of over 90 year-olds suffer from this disease. Alzheimer’s disease is a progressive and irreversible deterioration of cognitive abilities. The disease course is divided into three consecutive phases, which are the preclinical stage, the MCI (mild cognitive impairment) stage and dementia. In patients with Alzheimer’s disease, proteins are accumulated in the brain, which is associated with the destruction of nerve cells.

Within the nerve cells (particularly in the cortical and limbic brain regions) accumulation of neurofibrillary tangles from hyperphosphorylated tau protein (pTau(181)) occurs. Tau is expressed in neurons, where it stabilizes the microtubuli of the cytoskeleton. Incorrect phosphorylation of this protein leads to aggregation in the form of neurofibrils, which accumulate in the nerve cell bodies and interfere with the axonal transport.

Outside of the nerve cells, accumulation of senile plaques is observed, which mainly consist of beta-amyloids (Aβ). These are peptides that are produced by processing of the membrane-bound amyloid precursor protein (APP) and exist in various isoforms. In Alzheimer’s disease the breakdown of these peptides is impaired, which leads to deposits of especially beta-amyloid (1-40) (Aβ1-40) and beta-amyloid (1-42) (Aβ1-42) in the form of plaques.