Name: how the blood-brain barrier works
Uploaded: 2025-10-23T11:47:15.000Z
Duration: 49 s
Channel: JoVE

- [Instructeur] Het menselijk brein is geïsoleerd van de bloedsomloop via een beschermende barrière, de zogenaamde bloed-hersenbarrière, die bestaat uit endotheelcellen die de haarvaten van het centrale zenuwstelsel omsluiten. De bloed-hersenbarrière bestaat ook uit een basale membraan en gespecialiseerde neurale cellen, astrocyten genaamd, die in nauw contact staan met de haarvaten. Deze componenten helpen te voorkomen dat ongewenste stoffen over de grens komen.

Deze barrière controleert de chemische uitwisseling tussen het bloed en de interstitiële vloeistof in de hersenen, via verschillende soorten eiwitten die junctioncomplexen vormen. Over het algemeen kunnen alleen vetoplosbare verbindingen over de barrière worden gediffuseerd, terwijl in water oplosbare verbindingen kruisen via actief of passief transport.

de bloed-hersenbarrière

The Blood-brain Barrier

<h4>Overzicht</h4>

De bloed-hersenbarrière (BBB) verwijst naar het gespecialiseerde vaatstelsel dat de hersenen voorziet van voedingsstoffen in het bloed, terwijl het de beweging van ionen, moleculen, ziekteverwekkers en andere stoffen strikt reguleert. Het bestaat uit nauw met elkaar verbonden endotheelcellen aan de ene kant en astrocytenprojecties aan de andere kant. Samen vormen ze een semi-permeabele barrière die de hersenen beschermt en unieke uitdagingen met zich meebrengt voor de toediening van therapieën.

<h4>Cellulaire componenten</h4>

De BBB bestaat uit een verscheidenheid aan cellulaire componenten, waaronder endotheelcellen en astrocyten. Deze cellen delen een gemeenschappelijk basaalmembraan en regelen samen de doorgang van componenten tussen de bloedsomloop en de interstitiële vloeistof rond de hersenen.

Het eerste type cellulaire component, gespecialiseerde endotheelcellen, vormen de wanden van de hersencapillairen. Ze zijn verbonden door extreem nauwe en complexe intercellulaire verbindingen. Deze kruispunten creëren een selectieve fysieke barrière, waardoor de eenvoudige diffusie van de meeste stoffen wordt voorkomen, inclusief moleculen van gemiddelde tot grote grootte, zoals glucose en insuline.

Een tweede celtype, astrocyten, is een type gliacel van het centrale zenuwstelsel dat de endotheelcelfunctie, de bloedstroom en de ionenbalans in de hersenen beïnvloedt door interactie en nauwe associatie met het hersenvaatstelsel. Ze zorgen voor een directe link tussen het vaatstelsel en de neuronen: ze breiden processen uit – de zogenaamde eindvoeten – die zich aan de ene kant om de bloedvaten wikkelen, terwijl ze aan de andere kant intiem contact maken met neuronen bij synapsen.

<h4>Chemische uitwisseling</h4>

Het vermogen van een stof om de BBB te passeren en de efficiëntie waarmee deze uitwisseling plaatsvindt, hangt af van de chemische en moleculaire eigenschappen van elk molecuul of ion. Over het algemeen ondergaan kleine in vet oplosbare componenten, zoals zuurstof en kooldioxide, een snelle, eenvoudige diffusie door de endotheliale laag. Daarentegen vereisen grotere of in water oplosbare componenten vaak een selectiever proces dat passief of actief transport door een endotheelcel kan inhouden. De uitwisseling van deze stoffen vindt doorgaans langzamer plaats of vindt mogelijk helemaal niet plaats, afhankelijk van onder andere de relatieve overvloed en efficiëntie van molecuulspecifieke receptoren en transporteiwitten op het oppervlak van endotheelcellen.

<h4>De BBB beschermt de hersenen</h4>

De neurale bescherming die door de BBB wordt gefaciliteerd, is van cruciaal belang voor een goede gezondheid en functie van de hersenen. Ontregeling van de BBB kan leiden tot ernstige neurologische aandoeningen, waaronder multiple sclerose, infectie en ischemie als gevolg van een ontoereikende bloedtoevoer. Omgekeerd kan de activiteit van de BBB schadelijk zijn voor de behandeling van sommige neurologische ziekten door de doorgang van neuroactieve farmaceutische geneesmiddelen naar het centrale zenuwstelsel te voorkomen of aanzienlijk te verminderen. Om deze reden moeten medicijnen met neurologische doelwitten zo worden ontworpen dat ze de doorgang door de BBB vergemakkelijken.

De bloed-hersenbarrière

Overview

The blood-brain barrier (BBB) refers to the specialized vasculature that provides the brain with nutrients in the blood while strictly ...

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how the blood-brain barrier works

The blood-brain barrier is a specialized system of blood vessels that helps control what enters the brain. It delivers nutrients from the blood while tightly regulating ions, molecules, pathogens, and other substances. This semipermeable barrier protects the brain and also makes it harder to deliver some therapies.

The blood-brain barrier includes several cellular parts, especially endothelial cells and astrocytes. These cells share a common basement membrane and regulate movement between the circulation and the fluid around the brain. Specialized endothelial cells form the walls of cerebral capillaries. They are joined by very tight intercellular junctions, which create a selective physical barrier. This barrier blocks simple diffusion of most substances, including molecules as large as glucose and insulin.

Astrocytes are glial cells in the central nervous system. They influence endothelial cell function, blood flow, and ion balance in the brain. Astrocytes connect closely with the cerebral vasculature. Their processes, called endfeet, wrap around blood vessels on one end and make contact with neurons at synapses on the other. This gives them a direct link between blood vessels and nerve cells.

What crosses the barrier depends on a molecule's chemical and molecular properties. Small lipid-soluble substances, such as oxygen and carbon dioxide, move across by rapid simple diffusion. Larger or water-soluble substances usually need a more selective process. They may move through an endothelial cell by passive or active transport. In many cases, this exchange is slower, or it may not occur at all, depending on receptors and transport proteins on the endothelial surface.

The blood-brain barrier is essential for brain health and normal function. When it does not work properly, severe neurological diseases can occur, including multiple sclerosis, infection, and ischemia from poor blood supply. The barrier can also make treatment difficult because it can reduce the passage of neuroactive drugs into the central nervous system. For that reason, medicines aimed at the brain must be designed to pass through the blood-brain barrier.

How the Blood-Brain Barrier Works

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the blood-brain barrier

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key terms and concepts

Learn how the blood-brain barrier protects the brain, which cells build it, what can cross it, and why it matters for disease and drug delivery.

How the Blood-Brain Barrier Works | JoVE K12

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How the Blood-Brain Barrier Works

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