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

Liposome-encapsulated hemoglobin (LEH), a candidate for a red cell substitute, has been reported to be cleared from circulation primarily by the phagocytic system and modulate the production of inflammatory cytokines, such as TNF-α and IL-6, both in vivo and in vitro. In this study, we investigated the effects of liposome vesicles on the LPS-induced TNF-α production using a whole blood culture system. We also studied the effects of superoxide dismutase (SOD) encapsulated in liposome on the cytokine production. The pre-treatment of whole blood with liposome vesicles potentiated the LPS-induced TNF-α production. The encapsulation of SOD in the liposome vesicles suppressed the liposome-mediated augmentation of TNF-α production in a dose-dependent manner. These results suggest that encapsulation of SOD in LEH decreases the production of inflammatory cytokines from the phagocytic system which may be caused or augmented by LEH infusion in vivo.