Liver tryptase-positive mast cells and fibrosis in children with hepatic echinococcosis

The hepatic echinococcosis in children is a serious surgical problem. The aim of this study is to investigate the participation of mast cells in liver inflammatory reactions triggered by echinococcal cysts. Liver biopsy samples were collected from the tissue surrounding the cysts from 16 sick children (11 boys and 5 girls) in the course of abdominal surgery and from 5 controls. Light and ultrastructural immunocytochemistry was performed using monoclonal antibody against tryptase. Light microscopical immunocytochemistry revealed abundance of tryptase-positive (MCT) mast cells in the capsules of the cysts (43.58 cells/mm2). There were also observed greatly increased numbers of mast cells in portal tracts surrounding the cyst, compared to those of control biopsies (26.49 vs. 1.78 cells/mm2, p=0.0009, Mann-Whitney U test). Based on the ultrastructural appearance of tryptase-positive mast cell granules, morphological sings of activation of most of the mast cells were distinguished. In conclusion, we suggest that the accumulated and activated tryptase-positive mast cells in liver tissues surrounding the echinococcal cysts play a crucial role in modulation of the inflammatory liver response and could induce chronic inflammation and fibrogenesis, resulting in serious liver injury such as nonspecific reactive hepatitis

Distribution of ghrelin-positive mast cells in rat stomach

It is known that the gastrointestinal peptide hormone ghrelin is expressed in human and rodent B lymphocytes, T lymphocytes, monocytes and natural killer cells. However, there are no data about ghrelin expression by mast cells. These facts, as well as the common progenitor cells of mast cells and the above-mentioned immune cells, motivated us to undertake the current work in order to prove that like other granulocytes, rat gastric mast cells are capable of immunohistochemical expression of ghrelin. Gastric wall sections of Wistar rats were studied immunohistochemically for detection of ghrelin and tryptase and histochemically for toluidine blue in order to identify ghrelin-positive mast cells as well as to establish their localization and distribution. Results showed that mast cell granules expressed ghrelin. The ghrelin-positive mast cells were the least numerous as compared to tryptase-positive mast cells and toluidine blue-positive mast cells. Based on the observed expression of ghrelin in granules of mast cells localized in the rat gastric wall, we suggested that this type of cell can be regarded as an important source of ghrelin and suggested that ghrelin may exert different physiological functions, such as regulation of muscular, epithelial and glandular functions