Role in Fibrosis

These cells have been shown to be present in normal and pathologic situations of various organs, such as the liver, the kidney, and the heart [2-17, 29]. Ito cells, which are also called hepatic stellate cells or fat-storing cells, and which store vitamin A, play a central role in fibrogenesis of the liver [31]. These cells contain fat droplets which are rich in vitamin A in their cytoplasm. They activate and transdifferentiate into myofibroblast-like cells, and synthesize collagens during liver cirrhosis [32]. Recent reports have revealed that periacinar myofibroblasts, which are similar to Ito cells in morphology and functions, play a important role in pancreas fibrosis [18-22, 33, 34]. However, the detailed mechanisms of myofibroblast activation in pancreatic diseases are not known.

Fig. 1. The normal main pancreatic duct. a a-SMA-positive cells are found mainly in the outer region of the wall. Immunostain for a-SMA. X60. b Elastic fibers distributed throughout the wall. Elastica van Gieson. X60. Reproduced with permission [23].

Fig. 2. Transmission electron micrograph illustrating a typical myofibroblast (M) in the normal pancreatic duct. This cell has a triangular shape, a large nucleus, and dilated cisternae of the rough endoplasmic reticulum (arrow head). Bundles of microfilaments are observed throughout the cytoplasm (arrow). E = Ductal epithelium. Scale bar = 1 ^m. Reproduced with permission [23].

Fig. 2. Transmission electron micrograph illustrating a typical myofibroblast (M) in the normal pancreatic duct. This cell has a triangular shape, a large nucleus, and dilated cisternae of the rough endoplasmic reticulum (arrow head). Bundles of microfilaments are observed throughout the cytoplasm (arrow). E = Ductal epithelium. Scale bar = 1 ^m. Reproduced with permission [23].

Was this article helpful?

0 0

Post a comment