Molecular links between endothelial dysfunction and neurodegeneration in Alzheimer's disease

Alzheimer's disease (AD) is characterized by a progressive decline of cognitive functions and represents the most common form of dementia and a major cause of morbidity and mortality in the modern, westernized societies. There is accumulating evidence to support the hypothesis that a primary cerebral vascular dysfunction initiates a cascade of events that lead to neuronal injury in Alzheimer's dementia. The endothelium, in specific, constitutes a part of the blood brain barrier, the dysfunction of which is thought to play an important role to disturbed amyloid-β homeostasis and infiltration of the brain parenchyma with circulating toxic molecules in the disease. Furthermore, the endothelium itself is under certain conditions capable of producing neurotoxic and inflammatory factors, whereas common growth factors regulate the development and maintenance of both neurons and blood vessels. Reliance of both endothelial and neuronal cells on mitochondrial integrity and common molecular pathways for apoptosis also imply that there is a link between vascular pathology and neurodegeneration. The present article intends to review available evidence on molecular players implicated in the above mechanisms with the potential to develop biomarkers or novel therapeutic targets.