Effect of modified ultrafiltration on inflammatory mediators, coagulation factors, and other proteins in blood after an extracorporeal circuit.

Modified ultrafiltration (MUF) is a technique able to remove the excess body fluid and inflammatory mediators associated with the use of a cardiopulmonary bypass (CPB). It has been shown to reduce morbidity after cardiac operations in children. Application of MUF after adult cardiac operations has also been suggested being associated with a lower prevalence of early morbidity. However, the relationship between the concentration of mediators in the blood and postoperative morbidity remains yet to be proved. In this study, changes of various chemical mediators in the filtrate and blood before and after MUF have been evaluated in adult patients. Significant reductions of blood levels of inflammatory cytokines were not observed after MUF. On the other hand, MUF significantly elevated hematocrit, number of red cells, concentrations of albumine, coagulation Factor VII and X, platelet factor (PF)-4, and antithrombin (AT-) III.

Adsorption of inflammatory cytokines using a heparin-coated extracorporeal circuit.

Cardiopulmonary bypass (CPB) surgeries cause an increase in plasma inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) along with whole-body inflammatory responses. The inflammatory responses during a CPB treatment are reduced when using a heparin-coated extracorporeal circuit. Because many cytokines, growth factors, and complements are known to interact with heparin, the reduction of inflammatory responses by a heparin-coated circuit is likely to depend on this heparin-binding nature of the inflammatory cytokines. In this study, the inflammatory cytokines, TNF-alpha and IL-6, in fetal bovine serum (FBS) bound to a heparin-agarose beads (heparin beads)-column and the adsorptions were competitively inhibited on addition of heparin in a concentration-dependent manner. TNF-alpha in FBS required a higher concentration of heparin (50% concentration inhibition [IC50] > 20microg/ml) to inhibit adsorption to the heparin beads-column compared with IL-6, probably because of a stronger interaction between TNF-alpha and heparin-beads. TNF-alpha and IL-6 concentrations in human heparinized blood significantly increased after a CPB treatment. Although the adsorbed amount of IL-6 onto the heparin-coated circuit was low (less than 6% of free circulating IL-6), a significant amount of TNF-alpha adsorbed onto the circuit (23.9-755% of free circulating TNF-alpha). Therefore, the adsorption of inflammatory cytokines, especially TNF-alpha, onto the inner heparin-coated surface of an extracorporeal circuit may partly account for a reduction in inflammatory responses.