Increased activity of group II phospholipase A₂ in plasma in rat sodium deoxycholate induced acute pancreatitis

Abstract

Background-Two diVerent types of secretory phospholipase A 2 (PLA 2 ), pancreatic group I (PLA 2 -I) and non-pancreatic group II (PLA 2 -II), have been identified and postulated to be associated with the pathogenesis of various diseases, such as acute pancreatitis, septic shock, and multiple organ failure. Aims-To investigate the type of secretory PLA 2 responsible for its catalytic activity found in plasma and ascites of experimental acute pancreatitis. Methods-Acute pancreatitis of diVering severity was induced by the injection of diVerent concentrations (1% or 10%) of sodium deoxycholate (DCA) into the common biliopancreatic duct in rats, and catalytic PLA 2 activity in plasma and ascites were diVerentiated by anti-PLA 2 -I antibody and specific inhibitor of PLA 2 -II. Survival rate and plasma amylase, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were also measured. Results-In 1% and 10% DCA induced acute pancreatitis, plasma amylase values as well as PLA 2 activity in ascites were greatly increased. PLA 2 activity in plasma was also notably increased in 10% DCA induced acute pancreatitis, but not in 1% DCA induced acute pancreatitis. PLA 2 -I specific polyclonal antibody significantly inhibited PLA 2 activity in ascites but not that in plasma. In contrast, plasma PLA 2 activity was completely suppressed by PLA 2 -II specific inhibitor. In addition, a high mortality (93% at five hours) and a significant increase in plasma AST and ALT were noted in 10% DCA induced pancreatitis. Conclusion-Ascites PLA 2 activity is mainly derived from PLA 2 -I, whereas plasma PLA 2 activity is mostly derived from PLA 2 -II in severe acute pancreatitis, suggesting that increased plasma PLA 2 -II activity might be implicated in hepatic failure arising after severe acute pancreatitis. (Gut 1997; 41: 826-831)

Structures, Enzymatic Properties, and Expression of Novel Human and Mouse Secretory Phospholipase A2s

“…3 H]oleate-labeled Escherichia coli membranes as a substrate (35). The recombinant human sPLA 2 -IIE was partially purified from the culture supernatant by heparin-Sepharose affinity chromatography (Amersham Pharmacia Biotech; the sPLA 2 activity was eluted with 1 M NaCl) and characterized with respect to the Ca 2ϩ dependence and pH optimum as described previously (32).…”

“…Sequence alignment (Fig. 1) shows the presence of one distinct residue in sPLA 2 -IIE (His 35 ) where all other mouse and human sPLA 2 s have Gly. Although no FIG.…”

Effect of a Selective Inhibitor of Secretory Phospholipase A2, S-5920/LY315920Na, on Experimental Acute Pancreatitis in Rats

“…In this model, the activity of sPLA 2 -IB would also be high in the pancreas because the pro-sPLA 2 -IB should be activated by digestion with trypsin. Though the type of PLA 2 was not determined in trypsin-taurocholate pancreatitis model, the PLA 2 activity in plasma seems to be due to type II sPLA 2 as we have already reported on deoxycholateinduced pancreatitis in rats (19). However, the peak plasma PLA 2 activity of 118.1 nmol / (min × ml) at 3 h in the current PLA 2 -taurocholate model was more than 6-fold higher than that in the trypsin-taurocholate model, that is, 18.2 nmol / (min × ml) at 3 h (14), suggesting that more than 80% of PLA 2 activity in plasma should be due to exogenous pancreatic sPLA 2 -IB that leaked from the pancreatic tissue into the systemic circulation after being injected to the biliopancreatic duct.…”

“…Recent studies on human and experimental severe acute pancreatitis suggest that sPLA 2 -IIA rather than sPLA 2 -IB plays a central role in the development of local and systemic complications (7,8,14,15,19,27). In human patients with necrotizing pancreatitis, however, serum catalytic PLA 2 activity in one or two days after the onset is ascribable to pancreatic sPLA 2 -IB and corresponds well with the lung insufficiency observed in this early stage, which is thereafter replaced by nonpancreatic sPLA 2 -IIA (7,8).…”

“…Acute experimental pancreatitis was induced in 9-to 10-week-old male Wistar rats (Shizuoka Laboratory Center, Shizuoka) with a body weight of 220 -280 g (19). After fasting overnight, the animals were anesthetized with an intraperitoneal injection of pentobarbital (35 mg / kg), and a freely-moving catheter (DS-10 Disposal Swivel Kit; BRC Bioresearch Center, Nagoya) was placed in the jugular vein for the administration of drugs.…”