Synovial-type Phospholipase A2 Research Articles

Group I and group II phospholipase A2 in serum during normal and pathological pregnancy.

Phospholipase A2 groups I (pancreatic) and II (synovial) could be a link between local and systemic changes in pregnancy, reflected in catalytic activity. We studied whether normal pregnancy, preeclampsia, preterm labor and four other diseases have processes involving serum phospholipase A2s. Pancreatic and synovial-type phospholipase A2 were measured in the serum of 59 normal pregnant women and 89 patients with pathological pregnancy by newly developed time-resolved fluoroimmunoassays, and the catalytic activity by a radiochemical method using micellar phosphatidylcholine as substrate. During pregnancy weeks 6-14, synovial-type phospholipase A2 and catalytic activity were elevated 2- to 4-fold, but at 37 weeks values were normal. Pregnancy-induced hypertensive diseases increased by 4- to 10-fold the concentration of synovial-type phospholipase A2, reflected in catalytic activity. In 8 out of 14 cases, the enzyme was increased if the fetus was to be delivered prematurely. The enzymes studied remained within the reference interval in cases of hepatogestosis, fetal asphyxia, diabetes and twin pregnancy. Newly developed specific immunoassays for measuring different types of phospholipase A2 in serum can provide insights for clinical follow-up.

Immunochemical Detection of Group I and Group II Phospholipases A2 in Human Serum

Time-resolved fluoroimmunoassay was developed for the detection of synovial-type phospholipase A2 (s-PLA2) in human serum. This solid-phase, sandwich assay uses a polyclonal rabbit antibody raised against synovial-type group II PLA2 produced in Escherichia coli. No cross-reactions were detected between s-PLA2 and PLA2 from human or porcine pancreas, human ascitic fluid, or bee or cobra venom. In healthy individuals, the average concentration of s-PLA2 is 3.7 micrograms/L, with a 95% reference interval from 1.3 to 10.8 micrograms/L. We investigated pancreatic PLA2, which is a group I PLA2, and synovial-type group II PLA2 in sera of patients with hematological malignancies and septic fever. The concentration of s-PLA2 was increased in patient sera and correlated significantly with the catalytic activity of PLA2 and the concentration of C-reactive protein. No correlation with the concentration of pancreatic PLA2 was found. The results suggest that the increased catalytic activity of PLA2 in sera of patients with septic fever results from synovial-type group II PLA2.

Increased concentrations of synovial-type phospholipase A2 in serum and pulmonary and renal complications in acute pancreatitis.

The most important fatal complications of acute pancreatitis are respiratory dysfunction and anuria. Phospholipase A2 has been postulated to be associated with pathologies of various diseases, such as acute pancreatitis, septic shock and multiple injuries. We have recently developed immunoassays for the measurement of pancreatic and nonpancreatic synovial-type phospholipase A2. The present prospective study on 35 consecutive patients with acute pancreatitis indicated that the concentration of synovial-type phospholipase A2, the catalytic activity of phospholipase A2 and the concentration of C-reactive protein in serum were significantly higher in those patients suffering from acute pancreatitis who needed respirator treatment than in those who managed with spontaneous breathing, while there was no difference between these groups in the concentration of pancreatic phospholipase A2. The only significant difference between patients whose highest creatinine concentration rose up to 140 mumol/l and those whose highest creatinine concentration remained below this cutoff value was in their synovial-type phospholipase A2 values. The increased concentration of nonpancreatic synovial-type phospholipase A2 in serum was associated with pulmonary and renal complications. These results emphasize the role of synovial-type phospholipase A2 in the pathophysiology of acute pancreatitis.