Is Alzheimer's A Diabetes Type 3? Insulin Acts Like It Is!

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 memory loss.

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 study.

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