The researchers studied the effects of different forms of the amyloid beta peptide on human brain cells. Amyloid beta accumulation is one of two hallmarks of Alzheimer's disease and is considered a major target for researchers looking into therapies for the treatment of the disease. After death, most amyloid beta found in the brains of Alzheimer's patients is in fibrillar form -- long, insoluble fibers bound together in deposits called senile plaques; however, there are also soluble forms of amyloid beta, or oligomers, that may decisively contribute to neural degeneration.
The experiments conducted at UCI showed that the soluble forms of amyloid beta are much more toxic and lead to neuronal death in as little as 12 hours. The fibrillar form, meanwhile, does not actually kill the neurons, but slowly, over a period of 10 or more days, renders them useless.
Not known is whether the soluble amyloid beta in the Alzheimer brain eventually turns into the fibrillar kind, or whether the two are completely different.
The findings were published this week in the Journal of Neuroscience.
"These findings are quite significant because, although both fibrils and oligomers may contribute to dementia, they do so in very different ways over different time spans," said Jorge Busciglio, an assistant professor of neurobiology and behavior. "This complexity of the amyloid beta species will require more sophisticated therapeutic approaches. For example, it might be dangerous to create compounds that target fibrillar amyloid and try to break them up, because if the fibers dissolve into the soluble form, that could actually spee
Contact: Farnaz Khadem
University of California - Irvine