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Expression of the thrombin receptor in human liver: Up‐regulation during acute and chronic injury
Author(s) -
Marra Fabio,
DeFranco Raffaella,
Grappone Cecilia,
Milani Stefano,
Pinzani Massimo,
Pellegrini Giulia,
Laffi Giacomo,
Gentilini Paolo
Publication year - 1998
Publication title -
hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.488
H-Index - 361
eISSN - 1527-3350
pISSN - 0270-9139
DOI - 10.1002/hep.510270221
Subject(s) - in situ hybridization , immunostaining , thrombin , hepatic stellate cell , pathology , biology , liver injury , immunohistochemistry , liver regeneration , liver cytology , messenger rna , microbiology and biotechnology , regeneration (biology) , medicine , immunology , endocrinology , biochemistry , platelet , liver metabolism , gene
Thrombin is generated during tissue damage in several organs, including the liver, and participates in the process of tissue repair through proteolytic activation of a specific thrombin receptor(TR).The aim of this study was to investigate TR expression in human liver by immunohistochemistry and in situ hybridization. In normal liver, immunostaining for TR was present in the endothelial lining of the hepatic sinusoids. During chronic hepatitis, several cells expressing the TR were detected in the inflammatory infiltrate of portal tracts. In cirrhosis with chronic active hepatitis, expression of the TR was also present in mesenchymal cells of fibrous septa. TR expression was markedly up‐regulated during fulminant hepatitis, with the highest expression in mesenchymal cells in areas of regeneration. Up‐regulation of TR expression was associated with increased levels of TR messenger RNA (mRNA), as assessed by in situ hybridization and RNAse protection assay of liver RNA. Immunostaining of serial sections using specific cellular markers showed that different nonparenchymal cells contribute to TR expression during liver injury. TR expression was also shown in cultured human hepatic stellate cells, with increasing signal comparing activated versus quiescent cells. Because thrombin is rapidly generated after tissue damage, regulated TR expression may be involved in tissue remodeling and/or scarring during liver damage.