March 4, 2004

Researchers link protein to memory loss

By Megan Fellman

Researchers at Northwestern have discovered for the first time in humans the presence of a toxic protein that they believe to be responsible for the devastating memory loss found in individuals suffering from Alzheimer’s disease.

An understanding of this key molecular link in the progression of Alzheimer’s could lead to the development of new therapeutic drugs capable of reversing memory loss in patients who are treated early, in addition to preventing or delaying the disease. Help for individuals with pre-Alzheimer’s memory failure (mild cognitive impairment) also is envisioned. The findings were published online by the Proceedings of the National Academy of Sciences.

The research team, led by William L. Klein, professor of neurobiology and physiology, found up to 70 times more small, soluble aggregated proteins called “amyloid b-derived diffusible ligands” (ADDLs, pronounced “addles”) in the brain tissue of individuals with Alzheimer’s disease compared to that of normal individuals.

The clinical data strongly support a recent theory in which ADDLs accumulate at the beginning of Alzheimer’s disease and block memory function by a process predicted to be reversible. ADDLs have the ability to attack the memory-building activity of synapses, points of communication where neurons exchange information, without killing neurons.