Figure 2:

Effects of ageing on the NVU components and their interactions. Ageing can influence all the cells within the NVU and results in neurovascular uncoupling and neurodegeneration. In endothelial cells, ageing induces the secretion of pro-inflammatory factors such as TNF-a, IL-1B and VCAM-1, tight junctional protein disruption as a result of chronic neuroinflammation, and BBB impairment. It also increases astrocytic reactivity and impairs the role of astrocytic endfoot in connecting neurons and endothelial cells. BBB disruption and loss of communication with other cells result in neuronal dysfunction and neurodegeneration. Therefore, the regenerative capacities of neurons including synaptic plasticity, neurogenesis and synaptogenesis decrease significantly.