Brain Barriers and brain fluids research in 2020 and the fluids and barriers of the CNS thematic series on advances in in vitro modeling of the blood-brain barrier and neurovascular unit.

This editorial discusses advances in brain barrier and brain fluid research in 2020. Topics include: the cerebral endothelium and the neurovascular unit; the choroid plexus; the meninges; cerebrospinal fluid and the glymphatic system; disease states impacting the brain barriers and brain fluids; drug delivery to the brain. This editorial also highlights the recently completed Fluids Barriers CNS thematic series entitled, 'Advances in in vitro modeling of the blood-brain barrier and neurovascular unit'. Such in vitro modeling is progressing rapidly.