Doenças Neuroinfecciosas

Abstrato

Amyloid-�?² Oligomers and Aluminum Co-Aggregate to Form Toxic Amyloid Channels in Alzheimers Disease Brain: A New Amyloid-�?² Channel-Aluminum Hypotheses

Yoichiro Kuroda

Large numbers of senile plaques are thought to be characteristic of Alzheimer’s disease (AD), but these deposits are also a by-product of normal senescence. In AD and normal brains, senile plaques are primarily composed of amyloid-ß peptides (Aß P) with aluminum (Al). Evidence suggests the oligomerization of Aß P is part of the molecular mechanism of AD pathogenesis by forming neurotoxic amyloid channels. However, the relationship between Al and AD has been a subject of scientific debate for many years. The complex nature of Al bioavailability has made it difficult to evaluate its toxicity to the human brain. In 2004, Al concentration in CSF of AD patients analyzed to be 1.6 ± 0.4 times higher than normal people. Importantly, AD patients with more Al in CSF showed less MMSE score, indicating Al may decrease cognitive ability. Recently, Al accumulations in sporadic AD and familial AD brains were reported to be much higher than in normal control brains. Above its neurotoxicity, Al3+ has a crucial role as a cross-linker in ß-amyloid oligomerization. Therefore, I propose a hypothesis that ß-amyloid oligomerizes with Al, forming non-specific cation amyloid channels in cell membranes, which allows calcium to enter cells and finally causes neuronal death by together with Al’s own neurotoxicity.