Supplementation of host response by targeting nitric oxide to the macrophage cytosol is efficacious in the hamster model of visceral leishmaniasis and adds to efficacy of amphotericin B

• Published in: International journal for parasitology -- drugs and drug resistance 2016-08, Vol.6 (2), p.125-132
• Main Authors: Pandya, Sanketkumar, Verma, Rahul Kumar, Khare, Prashant, Tiwari, Brajendra, Srinivasarao, Dadi A., Dube, Anuradha, Goyal, Neena, Misra, Amit
• Format: Article
• Language: English
• Subjects: Amastigotes; Amphotericin B; Amphotericin B - administration & dosage; Animals; Antiprotozoal Agents - administration & dosage; Cell Survival - drug effects; Cricetinae; Disease Models, Animal; Drug Therapy, Combination; Leishmania donovani; Leishmania donovani - drug effects; Leishmania donovani - physiology; Leishmaniasis, Visceral - drug therapy; Macrophages - immunology; Macrophages - metabolism; Mice; Nanoparticles - administration & dosage; Nitric oxide donor; Nitroso Compounds - administration & dosage; PLGA; Promastigotes; Treatment Outcome
• ISSN: 2211-3207; 2211-3207
• DOI: 10.1016/j.ijpddr.2016.01.001

We investigated efficacy of nitric oxide (NO) against Leishmania donovani. NO is a mediator of host response to infection, with direct parasiticidal activity in addition to its role in signalling to evoke innate macrophage responses. However, it is short-lived and volatile, and is therefore difficult to introduce into infected cells and maintain inracellular concentrations for meaningful periods of time. We incorporated diethylenetriamine NO adduct (DETA/NO), a prodrug, into poly(lactide-co-glycolide) particles of ∼200 nm, with or without amphotericin B (AMB). These particles sustained NO levels in mouse macrophage culture supernatants, generating an area under curve (AUC0.08-24h) of 591.2 ± 95.1 mM × h. Free DETA/NO resulted in NO peaking at 3 h and declining rapidly to yield an AUC of 462.5 ± 193.4. Particles containing AMB and DETA/NO were able to kill ∼98% of promastigotes and ∼76% of amastigotes in 12 h when tested in vitro. Promastigotes and amastigotes were killed less efficiently by particles containing a single drug– either DETA/NO (∼42%, 35%) or AMB (∼90%, 50%) alone, or by equivalent concentrations of drugs in solution. In a pre-clinical efficacy study of power >0.95 in the hamster model, DETA/NO particles were non-inferior to Fungizone® but not Ambisome®, resulting in significant (∼73%) reduction in spleen parasites in 7 days. Particles containing both DETA/NO and AMB were superior (∼93% reduction) to Ambisome®. We conclude that NO delivered to the cytosol of macrophages infected with Leishmania possesses intrinsic activity and adds significantly to the efficacy of AMB. [Display omitted] •A prodrug of nitric oxide (NO) was delivered to macrophages harboring Leishmania.•Particles of NO donor were non-inferior to Fungizone® in a hamster infection model.•Particles containing amphotericin B and the NO donor were superior to Ambisome®.•The efficacious dose of amphotericin B was reduced by combining with the NO prodrug.•Targeted drug delivery can supplement the innate NO response against Leishmania.