Hippocampus (Image: Wikipedia)In a study that tested the efficacy of an insulin enhancing
drug in slowing or reducing the impact of Alzheimer's disease, Northwestern
University has reported findings
that insulin and an insulin enhancing drug can slow or prevent memory loss from Alzheimers caused by toxic proteins.
The scientists studied neurons from the hippocampus, a brain
structure that holds the brain's memory cells. In Alzheimer's disease, the
neurons in the hippocampus are attacked by toxic proteins called ADDLs (short
for "amyloid beta-derived diffusible ligands"), which is responsible for
Normally there is an abundance of insulin attached to nerve
Credit:FASEB Journalcells in the brain, but when attacked by ADDLs, the insulin disappears
noticeably. In the image on the right
you can see the ADDLs as green dots and the insulin receptors as red dots:
observe that where ADDLs have bonded to the neurons, insulin is scarce. (Credit:
The FASEB Journal) This discovery was made by the same research team in a prior
But now, by treating the hippocampus neurons with new insulin
and the insulin-sensitizing drug rosiglitazone,
the ADDLs are kept from binding to the neurons; thus, the synapses so important
to memory would be kept in tact.
"The discovery that anti-diabetic drugs shield synapses
against ADDLs offers new hope for fighting memory loss in Alzheimer's
disease," said lead author Fernanda G. De Felice, at the Federal
University of Rio de Janeiro, Brazil.
"Recognizing that Alzheimer's disease is a type of
brain diabetes points the way to novel discoveries that may finally result in
disease-modifying treatments for this devastating disease," adds Sergio T.
Ferreira, another member of the research team and a professor of biochemistry
in Rio de Janeiro.
The study's full findings are published in the February 2, 2009 Proceedings of the Naitonal Academy of Sciences (PNAS).
EurekAlert; Northwestern University