Activated perilobular, not periacinar, pancreatic stellate cells contribute to fibrogenesis in chronic alcoholic pancreatitis

Abstract

The authors investigated the role of activated perilobular, not periacinar, pancreatic stellate cells, in fibrogenesis in chronic pancreatitis, based on the distribution of myofibroblasts. Twenty-four patients with clinically diagnosed chronic alcoholic pancreatitis were studied histopathologically, immunohistochemically and quantitatively. In all cases, fibrosis was patchily distributed in the perilobular, or interlobular, areas, accompanied by a cirrhosis-like appearance; it had extended into the intralobular area in advanced cases. Seven patients had a massive or confluent loss of exocrine tissue, resulting in extensive interlobular fibrosis; the more extensive the interlobular fibrosis, the smaller the lobules. Immunoreactivity to alpha-smooth muscle actin, a myofibroblast marker, was found mostly in the same areas of the fibrosis, mainly the interlobular, and less often the periacinar, areas; the average percentage area of perilobular myofibroblasts was significantly higher than that of periacinar myofibroblasts in 20 randomly selected lobules (P > 0.001), in which the average value for the former was 38.03% (range: 13.54-61.32%; SD, 13.8%) and that for the latter was 4.85% (range 0.90-9.57%; SD, 2.22%). Fibrosis also immunostained positive for collagen types I and III. In conclusion, activated perilobular, not periacinar, pancreatic stellate cell contribute to fibrogenesis in chronic pancreatitis.