- 公益社団法人 日本ビタミン学会
- ビタミン (ISSN:0006386X)
- vol.68, no.9, pp.501-513, 1994-09-25 (Released:2018-03-30)
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. Under physiological conditions, these cells play key roles in the control 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. Whereas, under pathological conditions such as liver cirrhosis, these cells lose retinoids, and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan and adhesive glycoproteins. Morphology of these cells also changes from the star-shaped stellate cells to that of fibroblasts or myofibroblasts. ECM components regulate the morphology, proliferation, and functions of the stellate cells. L-ascorbic acid 2-phosphate, a long-acting vitamin C derivative, further modulates this cellular regulation by ECM components.