Expression of group II phospholipase A2 in the liver in acute pancreatitis

Background: A number of distinct secretory phospholipases A2 (PLA2) have be en characterized in the human. Elevated group II PLA2 serum levels are asso ciated with inflammatory diseases such as infections, septic shock, rheumat oid arthritis, multiple organ failure and acute pancreatitis. The cellular source of circulating group II PLA2 has not been defined unequivocally. The possible role of the liver as a source of circulating group II PLA2 in acu te pancreatitis was studied using liver biopsies from five patients operate d on for necrotizing acute pancreatitis and from two control liver samples. Methods: Reverse transcription polymerase chain reaction (RT PCR), norther n hybridization and in situ hybridization were used to study the expression of group II PLA2. Immunohistochemistry was used to study the localization of the group II PLA2 protein in liver cells and time-resolved fluoroimmunoa ssay to measure the plasma group H PLA2 content. Results: Expression of gro up II PLA2 was found in the livers of patients with acute pancreatitis by R T PCR and confirmed by northern hybridization. Group II PLA2 mRNA was local ized in hepatocytes by in situ hybridization. Faint immunopositivity was fo und in Kupffer cells. Time-resolved fluoroimmunoassay revealed elevated con centration of group II PLA2 in plasma samples. Only low levels of expressio n were found in the control livers. Conclusions: Group II PLA2 is expressed in the livers of patients suffering from acute pancreatitis but not in the livers of patients without pancreatic disease. The current results support the idea that hepatocytes are an important source of circulating group II PLA2 in inflammatory diseases.