Permeable endothelium and the interstitial space of brain

Area of Science:

• Neuroscience
• Vascular Biology
• Cell Biology

Background:

• Fenestrated vessels in the brain are typically absent but can be induced.
• Understanding the mechanisms and implications of brain fenestrated vessels is crucial for neurobiology.
• The blood-brain barrier's permeability is dynamically regulated.

Purpose of the Study:

• To investigate the induction of fenestrated vessels in the brain.
• To explore the role of urokinase and other factors in fenestrated vessel formation.
• To understand the solute transport and signaling mechanisms within the brain's interstitial spaces.

Main Methods:

• Agents stimulating urokinase production were used to induce fenestrated vessels.
• Analysis of solute transport through interstitial clefts and ventricular systems.
• Investigation of astrocyte gap junctions in volume transmission.

Main Results:

• Fenestrated vessels can be reversibly induced in the brain by agents that stimulate urokinase production.
• The glycocalyx and basal lamina are likely responsible for solute filtering in fenestrated vessels.
• Interstitial clefts serve as conduits for nonsynaptic volume transmission of signals and cell migration.

Conclusions:

• Urokinase, vascular endothelial growth factor, and metalloproteinases secreted by tumor cells may induce fenestrated vessels.
• The brain's cerebrospinal fluid (CSF) and interstitial clefts facilitate nonsynaptic volume transmission.
• Interstitial cleft characteristics change with brain maturation, impacting cell migration and solute transport.