Like explorers searching for the source of a long, expansive river, Alzheimer's disease (AD) researchers are seeking the origins of an exceedingly complex biochemical pathway, one that culminates in the onset of a debilitating condition that afflicts more than 4 million people in the United States alone. Along the way, investigators run into numerous tributaries, factors that, although proven to somehow contribute to disease pathogenesis, may or may not be connected or causally related to one another. Although recent findings in the field have been extremely encouraging, scientists are far from being able to precisely map and unify these factors into a synthesis that accurately describes exactly what's going on and why.
In the early 1990s, researchers hotly contested the cellular and molecular mechanisms of the disease; they debated which of amyloid beta (Aß) deposits or neurofibrillary tangles composed of the protein tau, was the more likely culprit for the...