Autopsy results collected from 79 nursing home patients confirmed the link between beta-amyloid protein and Alzheimer’s. Researchers reported that they discovered beta-amyloid in the brain plays a role in the earliest stages of Alzheimer’s, sometimes prior to the appearance of symptoms of dementia.
Sticky plaques of beta-amyloid in the brain and tangles of a protein referred to as tau inside brain nerve fibers are two characteristics of Alzheimer’s. Researchers disagree about which characteristic causes more damage although beta-amyloid buildup appears before tau. They also debate what came first: the presence of the beta-amyloid and tau which points to them as a cause of AD or are they the aftermath of nerve cells killed by an unidentified cause (making beta-amyloid and tau a byproduct of AD). William Teis, vice president for medical and scientific affairs at the Alzheimer’s Association, concurs, “what it doesn’t tell us is which comes first, the chicken or the egg – the disease or beta-amyloid.”
On the other hand, Dr. Dennis J. Selkoe, a neurologist at Harvard’s Brigham and Women’s Hospital, sounds confident that the study results are conclusive, “this work, coupled with early work, clearly points to amyloid build-up as the cause [of Alzheimer’s].”