Is circulating phospholipase A2 removed by large-pore continuous venovenous hemodiafiltration in septic acute renal failure?

Group II A phospholipase A2 (PLA2) produces many inflammatory lipid mediators, and the elevation in the level during sepsis has been correlated positively with the decrease in the arterial blood pressure. We studied the effect of large-pore continuous venovenous hemodiafiltration (LP-CVVHDF) on the plasma PLA2 concentration and the clearance mechanism during septic acute renal failure. The subjects were 10 consecutive patients with septic acute renal failure receiving CVVHDF. Simultaneous samples of arterial, and filter inlet and outlet blood, and ultradiafiltrate were collected before starting CVVHDF (0 hr), and 4 hr, 12 hr and 24 hr after starting CVVHDF. PLA2 activity was measured in plasma and ultradiafiltrate. We eluted PLA2 bound to hemofilter from patient and the classification of PLA2 type of eluting solution and ultradiafiltrate was done using Western blot analysis. Plasma clearance (mL/min) was 28.1+/-7.6 at 4 hr, 23.2+/-8.9 at 12hr and 17.5+/-8.0 at 24 hr. Plasma clearance at 4 hr was higher than that at either 12 hr or 24 hr. Plasma clearance mainly consisted of adsorption by LP-CVVHDF. The changes in arterial plasma PLA2 activity were not statistically significant. One mg/mL of heparin eluted PLA2 bound to the large-pore hemofilter. The PLA2 in eluting solution and in ultradiafiltrate were identified as an approximately 70 kD band in Western blot analysis using anti-human secretory II A-PLA2 monoclonal antibody. The results show that circulating PLA2 can be removed by adsorption with LP-CVVHDF to some extent and that plasma PLA2 activity is not significantly decreased. Because PLA2 clearance with LP-CVVHDF is estimated as <1% of total body PLA2 clearance, LP-CVVHDF could not be a clinically efficient therapy to remove the circulating PLA2.