The age-associated decline of the neurological and cognitive functions becomes more
and more serious challenge for the developed countries with the increasing number
of aged populations. The morphological and biochemical changes in the aging brain
are the subjects of many extended research projects worldwide for a long time. However,
the crucial role of the blood-brain barrier (BBB) impairment and disruption in the
pathological processes in age-associated neurodegenerative disorders received special
attention just for a few years. This article gives an overview on the major elements
of the blood-brain barrier and its supporting mechanisms and also on their alterations
during development, physiological aging process and age-associated neurodegenerative
disorders (Alzheimer's disease, multiple sclerosis, Parkinson's disease, pharmacoresistant
epilepsy). Besides the morphological alterations of the cellular elements (endothelial
cells, astrocytes, pericytes, microglia, neuronal elements) of the BBB and neurovascular
unit, the changes of the barrier at molecular level (tight junction proteins, adheres
junction proteins, membrane transporters, basal lamina, extracellular matrix) are
also summarized. The recognition of new players and initiators of the process of neurodegeneration
at the level of the BBB may offer new avenues for novel therapeutic approaches for
the treatment of numerous chronic neurodegenerative disorders currently without effective
medication.
