Changes in preoperative and postoperative lipoprotein-associated phospholipase A2 activity in patients with malignant obstructive jaundice

BACKGROUND Malignant obstructive jaundice (MOJ) leads to hyperbilirubinemia and systemic pathophysiological changes. The main clinical treatments for MOJ include radical pancreatoduodenectomy, palliative surgical treatment, and minimally invasive treatment, which can relieve biliary obstruction, drain bile, reduce jaundice, and improve liver function. In rat models, hepatic exposure to endotoxin resulted in rapid increases in biliary and plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) levels, and our previous study revealed that Lp-PLA2 activity was strongly associated with liver damage. The present study aimed to clarify the serum Lp-PLA2 activity changes and evaluate the associations between Lp-PLA2 activity and laboratory parameters in MOJ patients preoperatively and postoperatively. METHODS Twenty-one patients with MOJ were enrolled in this prospective study. Lp-PLA2 activity and other laboratory parameters were analyzed using a Hitachi 7600 automatic biochemical analyzer. Spearman correlation coefficients, percent differences, and dynamic difference plots were used to evaluate the changes in preoperative and postoperative Lp-PLA2 activity and the associations of Lp-PLA2 activity with other laboratory parameters. RESULTS The postoperative Lp-PLA2 activity at 1 day [646 (range, 175-1,025) U/L], 1 week [419 (range, 144-949) U/L], and day of hospital discharge [347 (range, 165-698) U/L] differed significantly from the preoperative baseline activity (636 (range, 172-1,664) U/L; P<0.05 for all). Lp-PLA2 activity was correlated with total bilirubin (TB) at specific time points (P<0.05 for all). The percent differences and dynamic difference graphs revealed that Lp-PLA2 activity, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and TB gradually decreased after biliary obstruction was relieved by surgical treatment. CONCLUSIONS Lp-PLA2 activity in MOJ patients was associated with biliary obstruction and liver damage. Serum Lp-PLA2 can be used as a novel indicator for biliary obstruction severity and treatment monitoring.