The Japan Academy

About the Cover

Vol. 82 No. 4 (2006)

Vol. 82 No. 4 (2006)

A hepatic stellate cell in the pig liver

  Hepatic stellate cells (previously termed as fat- or vitamin A-storing cell, Ito cells, lipocytes) are located on the outer surface of liver capillaries (sinusoids), encompassing endothelial cells with long branching cytoplasmic processes. Lateral edges of the processes are studded with many thorn-like microprojections, which contact with hepatocytes. Hepatic stellate cells play multiple roles, including vitamin A-storage, synthesis of collagen, and probably regulation of sinusoidal blood flow. Stellate cells are activated upon liver injury, and transdifferentiate to myofibroblasts, which are involved in proliferation, contractility, fibrogenesis, cytokine release, matrix protease release and vitamin A loss. Scientists are searching for the mechanism of stellate cell activation to prevent and cure liver cirrhosis following chronic hepatitis. In mammals, equivalent vitamin A-storing stellate cells distribute in multiple splanchnic organs, including pancreas, intestine, kidney and lung. Studies of stellate cell activation are expected to provide a major advance in the study of fibrosis not only in the liver but also in other splanchnic organs.
  The cover illustration shows two hepatic stellate cells which surround sinusoids with cytoplasmic processes. Pig liver. Rapid Golgi silver method.

(Photo and Caption were prepared by Kenjiro Wake, Emeritus Professor, Tokyo Medical and Dental University)