Blood-brain barrier components (BBB components)

The blood-brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that prevents solutes in the circulating blood from non-selectively crossing into the extracellular fluid of the central nervous system (CNS) (Daneman R, Prat A. Cold Spring Harb Perspect Biol. 2015). It is primarily composed of brain microvascular endothelial cells (BMECs) connected by tight junctions, supported by pericytes, astrocytes, and a basement membrane, collectively known as the neurovascular unit (Abbott NJ, et al. Neurobiol Dis. 2010). The BBB's primary biological function is to maintain brain homeostasis by regulating the influx of essential nutrients and the efflux of metabolic waste products while shielding the brain from systemic toxins and pathogens (Banks WA. J Neuroimmunol. 2005). In various pathological conditions, such as multiple sclerosis, stroke, and Alzheimer's disease, the integrity of the BBB is often compromised, contributing to neuroinflammation and disease progression (Sweeney MD, et al. Nat Rev Neurol. 2018). From a pharmacological perspective, the BBB represents a significant challenge for drug delivery, as it excludes over 98% of small-molecule drugs and nearly all large-molecule therapeutics (Pardridge WM. NeuroRx. 2005). Current strategies to interact with BBB components include osmotic disruption, inhibition of efflux transporters like P-glycoprotein, and the use of 'Trojan horse' antibodies that target receptors like the transferrin receptor to facilitate transcytosis (Pardridge WM. J Cereb Blood Flow Metab. 2012).

Other names

Blood-brain barrierBBBNeurovascular unit componentsBrain microvascular endothelial cellsTight junction proteins

Modulation of the blood-brain barrier involves osmotic disruption to increase paracellular permeability, inhibition of efflux transporters like P-glycoprotein to increase drug accumulation, or utilizing receptor-mediated transcytosis (e.g., via Transferrin receptor) to shuttle large molecules across the barrier.