Hepatic stellate cells--from the viewpoint of retinoid handling and function of the extracellular matrix.
Hepatic stellate cells (vitamin A-storing cells, lipocytes, fat-storing cells, Ito cells) exist in the perisinusoidal space of the hepatic lobule, and store 80% of retinoids in the whole body as retinyl palmitate in lipid droplets in the cytoplasm. In physiological conditions, these cells play pivotal roles in the regulation of retinoid homeostasis; they express specific receptors for retinol-binding protein (RBP), a binding protein specific for retinol, on their cell surface, and take up the complex of retinol and RBP by receptor-mediated endocytosis. By contrast, in pathological conditions such as liver fibrosis, these cells lose retinoids, and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan and adhesive glycoproteins. The morphology of these cells also changes from the star-shaped stellate cells to that of fibroblasts or myofibroblasts. It is concluded that three-dimensional structure of the ECM components reversibly regulates the morphology, proliferation, and functions of the hepatic stellate cells.
Senoo
H
H
Department of Anatomy, Akita University School of Medicine, Japan.
Sato
M
M
Imai
K
K
D000818:Animals; D005109:Extracellular Matrix / Q000502:physiology* / Q000648:ultrastructure; D008099:Liver / Q000166:cytology* / Q000378:metabolism / Q000648:ultrastructure; D012176:Retinoids / Q000378:metabolism*
D012176:Retinoids