Toxic Protein Could Explain Alzheimer's & Lead to Breakthroughs
(Northwestern University, Illinois, 8/18/03)

William L. Klein of Northwestern University, and colleagues, report finding extremely high concentrations of toxic aggregated proteins, called amyloid b-derived diffusible ligands (ADDLs) in the brains of Alzheimer's sufferers, as compared with their peers. These findings support a recent theory explaining the pathology of Alzheimer’s Disease as resulting from the accumulation of ADDLs, which block the functioning of synapses, preventing the building of memories. Scientists have traditionally cited the presence of amyloid fibrils, referred to as “plaques,” as markers for Alzheimer’s; even though they had not established a clear correlation between the plaques and neurological deficits. Doubt was cast on the plaque theory by recent experiments where amyloid beta antibodies reversed memory deficits in mice, even when plaques persisted. Scientists speculated that the antibodies reactivated the memory function by neutralizing the ADDLs. And now that Klein’s team has found ADDLs in human brains, there is increased reason to suspect that the ADDLs, not the “plaques,” produce the memory loss.