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Differential effects of amphotericin B and liposomal amphotericin B on inflammatory cells in vitro
R Baronti1, E Masini, L Bacciottini
1Department of Preclinical and Clinical Pharmacology, Mario Aiazzi Mancini, University of Florence, Italy.
Objective And Design:
To understand whether the pseudo-allergic reactions to amphotericin B (AmB) administration are due to AmB or to the solubilizing vehicles, a study was designed to evaluate the effects of AmB, liposomal AmB, (L-AmB), AmB-deoxycholate micellar complex (AmB-DC) and deoxycholate (DC) on the responses of rat serosal mast cells (RSMC) and of human basophils (HB), in vitro.
Materials And Methods:
Serosal mast cells were obtained by density gradient centrifugations from male Wistar albino rats. Partially purified HB were obtained from healthy donors. The cells were exposed to AmB, L-AmB, AmB-DC and DC. Histamine release was measured fluorometrically, and the release of lactic dehydrogenase (LDH) was measured spectrophotometrically. HB activation was evaluated cytofluorimetrically by CD63 expression.
Results:
AmB and L-AmB did not evoke histamine or LDH release from either RSMC or HB. CD63 expression was not induced in HB challenged with AmB and L-AMB. On the other hand, AmB-DC and DC produced a cytotoxic histamine release from both RSMC and HB, and a sustained increase of CD63 expression on HB.
Conclusions:
Only AmB-DC was able to induce the release of inflammatory mediators from RSMC and HB. Conceivably, the cytotoxic effect is accounted for by the micellar complexes with DC, which has been confirmed as a powerful histamine releaser, and held responsible for the pseudo-allergic reactions after AmB-DC administration. The data lend support to a better safety profile of L-AmB.
Insights
Pseudo-allergic reactions to amphotericin B (AmB) are caused by deoxycholate (DC), not AmB itself. Liposomal AmB (L-AmB) shows a better safety profile, as only AmB-deoxycholate (AmB-DC) and DC induced histamine release and cell activation.
Area of Science:
- Pharmacology
- Immunology
- Toxicology
Background:
- Pseudo-allergic reactions are a concern with amphotericin B (AmB) formulations.
- The role of solubilizing agents in these reactions requires clarification.
Purpose of the Study:
- To differentiate the effects of AmB from its vehicles on immune cells.
- To evaluate the in vitro impact of AmB, liposomal AmB (L-AmB), AmB-deoxycholate (AmB-DC), and deoxycholate (DC) on rat serosal mast cells (RSMC) and human basophils (HB).
Main Methods:
- RSMC and HB were isolated and exposed to AmB, L-AmB, AmB-DC, and DC.
- Histamine and lactate dehydrogenase (LDH) release were measured.
- Human basophil activation was assessed via CD63 expression.
Main Results:
- AmB and L-AmB did not induce histamine or LDH release, nor CD63 expression.
- AmB-DC and DC caused cytotoxic histamine release from both RSMC and HB.
- AmB-DC and DC significantly increased CD63 expression on HB.
Conclusions:
- AmB-DC, specifically the deoxycholate (DC) component, is responsible for pseudo-allergic reactions by inducing histamine release.
- L-AmB demonstrates a superior safety profile compared to AmB-DC.
- DC is identified as a potent histamine releaser contributing to adverse reactions.