ABSTRACT
Leishmaniasis chemotherapy remains very challenging due to high cost of the drug and its associated toxicity and drug resistance, which develops over a period of time. Combination therapies (CT) are now in use to treat many diseases, such as cancer and malaria, since it is more effective and affordable than monotherapy. CT are believed to represent a new explorable strategy for leishmaniasis, a neglected tropical disease caused by the obligate intracellular parasite Leishmania In the present study, we investigated the effect of a combination of a traditional Indian medicine (ayurveda), a natural product curcumin and miltefosine, the only oral drug for visceral leishmaniasis (VL) using a Leishmania donovani-hamster model. We developed an oral nanoparticle-based formulation of curcumin. Nanoformulation of curcumin alone exhibited significant leishmanicidal activity both in vitro and in vivo In combination with miltefosine, it exhibited a synergistic effect on both promastigotes and amastigotes under in vitro conditions. The combination of these two agents also demonstrated increased in vivo leishmanicidal activity accompanied by increased production of toxic reactive oxygen/nitrogen metabolites and enhanced phagocytic activity. The combination also exhibited increased lymphocyte proliferation. The present study thus establishes the possible use of nanocurcumin as an adjunct to antileishmanial chemotherapy.
Subject(s)
Antiprotozoal Agents/pharmacology , Curcumin/pharmacology , Leishmania donovani/drug effects , Leishmaniasis, Visceral/drug therapy , Nanoparticles/administration & dosage , Phosphorylcholine/analogs & derivatives , Administration, Oral , Animals , Cell Proliferation/drug effects , Cricetinae , Disease Models, Animal , Drug Carriers , Drug Combinations , Drug Resistance/drug effects , Drug Synergism , Humans , Leishmania donovani/growth & development , Leishmaniasis, Visceral/immunology , Leishmaniasis, Visceral/metabolism , Leishmaniasis, Visceral/parasitology , Lymphocytes/drug effects , Lymphocytes/immunology , Male , Medicine, Ayurvedic , Nanoparticles/ultrastructure , Phagocytosis/drug effects , Phosphorylcholine/pharmacology , Reactive Nitrogen Species/agonists , Reactive Nitrogen Species/metabolism , Reactive Oxygen Species/agonists , Reactive Oxygen Species/metabolismABSTRACT
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 â¼200 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 â¼98% of promastigotes and â¼76% 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 (â¼42%, 35%) or AMB (â¼90%, 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 (â¼73%) reduction in spleen parasites in 7 days. Particles containing both DETA/NO and AMB were superior (â¼93% 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.
