CSF Flow / Blood contamination / Fluid compartments / Barriers in the brain

Blood contamination

Example: 20240216 Aon Neurosciences pS129 aSyn / CSF MN- 50 ng/mL

CSF Flow

CSF production at choroid plexus and so on

1. CSF flow along perivascular space driven by pulsatility
2. CSF dispersion within parenchyma supported by AQP4
3. CSF mixed with ISF accumulation in perivenous space
4. Drain out of fluid through meningeal lymphatic vessels

Fluid compartments in the brain

• intracellular fluid (ICF) (60-68%)

• interstitial fluid (ISF) (or extracellular fluid) (12-20%)

• blood (10%)

• CSF (10%)

• ECF

• Parenchyma (cells)

• Ventricular system (CSF): no protein binding of drugs takes place here.

• Human brain generates 7 g of proteins a day. 3.6 g of proteins may be drained a day. The rest would be degraded

• There is the BBB between ECF and CSF (?, 아래 그림 보니 맞는 말 같은데..)

Barriers in the brain

	tight junctions	function	note
BBB Between blood and parenchyma	Tight junctions between the blood endothelial cells constitute the BBB.	restricting macromolecules to move freely from the blood to the brain parenchyma	perivascular space (=Virchow-Robin space): is located between endothelial cells and astrocytic endfeet. ii) filled with CSF iii) tight junction 의 도과(? 있다) Fluid and solutes in the perivascular space located between endothelial cells and astrocytic endfeet (expressing the water channel aquaporin-4 (AQP4)) diffuses into the brain parenchyma. (ISF). iii) perivascular space 중 일부 도 Glymphatic system (역시 그 도 astrocytic end foot)
Blood-CSF Between blood and CSF	tight junctions between the choroid plexus epithelial cells	restricting macromolecules to move freely from the blood to CSF (?)