Effects of lipid formulations of amphotericin B on activity of human monocytes against Aspergillus fumigatus.

The immunomodulatory effects of liposomal amphotericin B (LAMB), amphotericin B lipid complex, and amphotericin B colloidal dispersion (ABCD) on antifungal activity of human monocytes (MNCs), an important component of antifungal host defense, against Aspergillus fumigatus were compared to those of deoxycholate amphotericin B (DAMB). MNCs from healthy volunteers were incubated with 1 or 5 microg/ml DAMB and 5 or 25 microg/ml lipid formulations for 22 h. Drug-pretreated or untreated MNCs were then washed and assayed for the following: (i) activity against A. fumigatus hyphae by XTT assay at MNC:hypha ratios of 10:1 and 20:1; (ii) production of superoxide anion (O2-) from MNCs in response to hyphae by cytochrome c reduction; (iii) production of hydrogen peroxide (H2O2) and H2O2-dependent intracellular intermediates (DIIs), such as OH- and HOCl, from MNCs in response to A. fumigatus culture supernatant by flow cytometric measurement of dihydrorhodamine-1,2,3 oxidation. With the exception of 1 microg/ml DAMB and 5 mug/ml LAMB or ABCD at 10:1, all amphotericin B formulations at both concentrations and MNC:hypha ratios enhanced MNC-induced damage of A. fumigatus hyphae compared to results with untreated cells (P < 0.01). While MNC O2- production upon hyphal challenge, an early event in oxidative burst, was not affected by the drugs, production of H2O2 and DIIs, late events, were significantly increased by all four drugs (P < 0.01). At clinically relevant concentrations, both conventional amphotericin B and its lipid formulations enhance antihyphal activity of MNCs against A. fumigatus in association with significant augmentation of H2O2 and DIIs but not O2-, further demonstrating the immunomodulatory antifungal activities of these agents.

Differential expression of cytokines and chemokines in human monocytes induced by lipid formulations of amphotericin B.

The immunomodulatory effects of liposomal amphotericin B (LAMB), amphotericin B lipid complex (ABLC), and amphotericin B colloidal dispersion (ABCD) on mRNA and protein profiles of five cytokines and chemokines expressed by human monocyte-enriched mononuclear leukocytes (MNCs) were comprehensively evaluated by semiquantitative reverse transcription-PCR and enzyme-linked immunosorbent assays; they were compared to those of deoxycholate amphotericin B (DAMB). mRNAs of interleukin-1beta (IL-1beta), IL-1 receptor antagonist (IL-1ra), tumor necrosis factor alpha (TNF-alpha), monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 1beta (MIP-1beta) were assessed after treatment of MNCs with each drug for 0.5, 2, 6, and 22 h. The cytokine protein profiles were obtained after incubation of MNCs with the drugs for 2 h (TNF-alpha) or 6 h (all the others). In the mRNA studies, DAMB resulted in an early increase of inflammatory cytokines or chemokines IL-1beta, TNF-alpha, MCP-1, and MIP-1beta (2 to 6 h) and in a late increase of anti-inflammatory IL-1ra (22 h). ABCD showed a general similar trend of inflammatory gene up-regulation. LAMB and ABLC decreased or did not affect IL-1beta and TNF-alpha, whereas ABLC additionally decreased MIP-1beta. In protein measurement studies, DAMB and ABCD up-regulated production of IL-1beta (P < 0.05), decreased the IL-1ra/IL-1beta ratio, and up-regulated the production of MCP-1 and MIP-1beta. In comparison, LAMB and ABLC down-regulated or did not affect the production of these cytokines/chemokines compared to untreated MNCs; furthermore, ABLC tended to increase the IL-1ra/IL-1beta ratio. These studies demonstrate that amphotericin B formulations differentially affect gene expression and release of an array of proinflammatory and anti-inflammatory cytokines that potentially may explain the differences in infusion-related reactions and dose-dependent nephrotoxicity as well as modulation of the host immune response to invasive fungal infections.