Development of the choroid plexus and blood-CSF barrier

Abstract

Well-known as one of the main sources of cerebrospinal fluid (CSF), the choroid plexuses have been, and still remain, a relatively understudied tissue in neuroscience. The choroid plexus and CSF (along with the blood-brain barrier proper) are recognized to provide a robust protective effort for the brain: a physical barrier to impede entrance of toxic metabolites to the brain; a “biochemical” barrier that facilitates removal of moieties that circumvent this physical barrier; and buoyant physical protection by CSF itself. In addition, the choroid plexus-CSF system has been shown to be integral for normal brain development, central nervous system (CNS) homeostasis, and repair after disease and trauma. It has been suggested to provide a stem-cell like repository for neuronal and astrocyte glial cell progenitors. By far, the most widely recognized choroid plexus role is as the site of the blood-CSF barrier, controller of the internal CNS microenvironment. Mechanisms involved combine structural diffusion restraint from tight junctions between plexus epithelial cells (physical barrier) and specific exchange mechanisms across the interface (enzymatic barrier). The current hypothesis states that early in development this interface is functional and more specific than in the adult, with differences historically termed as “immaturity” actually correctly reflecting developmental specialization. The advanced knowledge of the choroid plexus-CSF system proves itself imperative to understand a range of neurological diseases, from those caused by plexus or CSF drainage dysfunction (e.g., hydrocephalus) to more complicated late-stage diseases (e.g., Alzheimer's) and failure of CNS regeneration. This review will focus on choroid plexus development, outlining how early specializations may be exploited clinically.

Moderate Renal Failure Accentuates T1 Signal Enhancement in the Deep Cerebellar Nuclei of Gadodiamide-Treated Rats

“…35 Indeed, tight junctions of the blood-CSF barrier are more permeable than those of the blood-brain barrier. 36,37 Moreover, Jost et al 38 recently demonstrated T1 enhancement in the CSF 1 minute after a single injection of all categories of GBCAs in rats, and Naganawa et al 39 reported T1 enhancement in the CSF after injection of a single dose of gadoteridol in healthy volunteers, from 1.5 hours postinjection, increasing until 3 hours postinjection, and then slowly decreasing. The DCN are adjacent to the CP of the fourth ventricle and are particularly rich in metals such as iron, copper, and zinc.…”

Involvement of Neuroinflammation during Brain Development in Social Cognitive Deficits in Autism Spectrum Disorder and Schizophrenia

“…Because the cerebellum is located adjacent to the fourth ventricle and the cerebral ventricles are partly surrounded by the choroid plexus in young children (Su and Young, 2011;Liddelow, 2015), impaired cellular metal homeostasis probably induces hyperactivation of the cerebellum via dysfunction of choroid plexus and fourth ventricle in young children with ASD. Neuronal hyperactivation can trigger M1 polarization of microglia in the cerebellum, and then M1 microglial-mediated neuroinflammation and neural network dysfunction may extend to the related tissues under inhibition in the M2 state.…”

Covalent nano delivery systems for selective imaging and treatment of brain tumors

“…Different from BBB, the capillary cells of the BCSFB do not have tight junctions, and they are fenestrated allowing for free permeation of various substances [142]. Circumscribing these capillaries are polarized epithelial cells with tight junctions, preventing free diffusion between blood and surrounding CSF.…”