For the neurons in the brain to work smoothly and be able to process information, the central nervous system needs a strictly regulated environment. This is maintained by the blood-brain barrier, whereby specialized brain endothelial cells lining the inner walls of blood vessels regulate the exchange of molecules between the circulatory and nervous systems. Earlier studies have shown that various functions that are dependent on these cells, such as the integrity of the blood-brain barrier or the regulation of blood supply to the brain, decline over the course of a person’s life. This dysregulation leads to a dysfunction of the brain vasculature and is therefore a major contributor to medical conditions such as strokes and dementia.