Hepatic stellate cell
Also known as: Ito cell, fat-storing cell, perisinusoidal cell, lipocyte
Hepatic stellate (Ito) cells are pericyte-like cells in the space of Disse that store vitamin A. When the liver is injured they become collagen-producing myofibroblasts and drive fibrosis.
Overview
In the healthy liver, stellate cells are quiescent. They hold cytoplasmic lipid droplets that contain most of the body's vitamin A as retinyl esters, and their long processes wrap around the sinusoids.
After injury they are activated by cytokines from Kupffer cells and damaged hepatocytes (TGF-β, PDGF), by reactive oxygen species and by apoptotic bodies. Activated cells lose their retinoid droplets and change into proliferative, contractile myofibroblasts. These secrete collagen types I and III and tissue inhibitors of metalloproteinases (TIMPs). Collagen laid down in the space of Disse "capillarises" the sinusoids. Contraction of the cells raises intrahepatic resistance. Both processes lead towards cirrhosis and portal hypertension.
- Location
Perisinusoidal space (of Disse), between the sinusoidal endothelium and the hepatocytes.
Anatomy
- Histology
Hard to see on H&E. Shown by fat stains, vitamin-A autofluorescence or immunostaining (desmin; α-SMA when activated).
Function
- Store and release vitamin A.
- Maintain the perisinusoidal extracellular matrix.
- Regulate sinusoidal blood flow (contractility).
- Act as the main fibrogenic cell after injury.
Clinical significance
Liver fibrosis
Stellate-cell activation is the final common pathway of fibrosis whatever the cause: viral, alcohol, metabolic, cholestatic or toxic. Removing the cause (for example, curing hepatitis C) lets activated cells revert or die, so early fibrosis can regress. Hypervitaminosis A can itself cause perisinusoidal fibrosis.
Compiled from standard anatomy and physiology references — see the Digestive System sources. For education only; not medical advice.