Liposome-encapsulated superoxide dismutase suppresses liposome-mediated augmentation of TNF-alpha production from peripheral blood leucocytes

Liposome-encapsulated hemoglobin (LEH), a candidate for a red cell substitu te, has been reported to be cleared from circulation primarily by the phago cytic, system and modulate the production of inflammatory cytokines, such a s TNF-alpha and IL-6, both in vivo and in vitro. In this study, we investig ated the effects of liposome vesicles on the LPS-induced TNF-alpha producti on using a whole blood culture system. We also studied the effects of super oxide dismutase (SOD) encapsulated in liposome on the cytokine production. The pre-treatment of whole blood with liposome vesicles potentiated the LPS -induced TNF-alpha production. The encapsulation of SOD in the liposome ves icles suppressed the liposome-mediated augmentation of TNF-alpha production in a dose-dependent manner. These results suggest that encapsulation of SO D in LEH decreases the production of inflammatory cytokines from the phagoc ytic system which may be caused or augmented by LEH infusion in vivo. (C) 2 001 Elsevier Science Inc. All rights reserved.