Lipofuscin and Aβ42 exhibit distinct distribution patterns in normal and Alzheimer's disease brains

Our recent study has provided evidence that Aβ42, a 42 amino acid fragment of the amyloid precursor protein, accumulates intracellularly in vulnerable neurons. This study appears to show that neurons lyse and form dense-core amyloid plaques in Alzheimer's disease (AD) entorhinal cortex. Previous studies have suggested that intracellular Aβ42 co-localizes with lipofuscin in neurons and those increased levels of lipofuscin and Aβ42 are associated with AD. Other studies have questioned this relationship and suggested that β-amyloid and lipofuscin are not co-localized and that their levels are independent of one another in AD and age-matched control tissues. In an effort to resolve this controversy, we investigated the relative spatial relationship of intracellular Aβ42 and lipofuscin in AD brains tissue using a novel combined immunohistochemical:histochemical staining protocol. Our results show separate and distinct localization patterns of Aβ42 and lipofuscin in neurons and amyloid plaques.