Choroid plexus and its relations with age-related diseases.

The choroid plexus is composed of epithelial cells situated on the basal layer. The tight junctions between adjacent choroid plexus epithelial cells establish the blood-cerebrospinal fluid barrier. This barrier, in conjunction with the blood-brain barrier, is crucial for the homeostasis of the brain microenvironment. The choroid plexus epithelium secretes cerebrospinal fluid, growth factors, neuropeptides, and lipids into the ventricles and also serves as a gateway for immune cells to enter the brain. The pathophysiology of aging and neurodegenerative diseases remains largely enigmatic, with an increasing body of research linking the choroid plexus to the etiology of these age-related disorders. In this review, we summarize the known relationship between the choroid plexus epithelium and age-related diseases, aiming to provide new therapeutic clues for these disorders.