antimony-potassium-tartrate and Leishmaniasis--Visceral

The parasite

Topics: Animals; Antimony Potassium Tartrate; Cytosol; Drug Resistance; Female; Host-Parasite Interactions; Leishmania donovani; Leishmaniasis, Visceral; Macrophages, Peritoneal; Male; Mice, Inbred BALB C; Mitochondrial Proteins; Oxidative Stress; Peroxidases; Phosphorylcholine; Protozoan Proteins; Reactive Oxygen Species; Trypanocidal Agents

Antimonials (Sb) were used for decades for chemotherapy of visceral leishmaniasis (VL). Now abandoned in the Indian subcontinent (ISC) because of

Topics: Antimony; Antimony Potassium Tartrate; Antiprotozoal Agents; Drug Resistance; Genetic Variation; Genomics; Humans; India; Leishmania donovani; Leishmaniasis, Visceral; Metabolomics; Nepal; Protozoan Proteins

Strains of the same Leishmania parasite species, isolated from different host organisms, may exhibit unique infection profiles and induce a change in the expression of microRNAs among host macrophages and in model host mice. MicroRNAs (MiR) are endogenous molecules of about 22 nucleotides that are involved in many regulatory processes, including the vertebrate host immune response. In this respect, the infectivity and susceptibility to antimonials of two L. infantum strains, BH46, isolated from human, and OP46, isolated from symptomatic dog, were characterized in J774 macrophages and BALB/c mice. Parasite burden was assessed in the liver, spleen, and bone marrow using the serial limiting dilution technique. A higher parasite burden was observed in the spleen and bone marrow of animals infected with OP46 compared to BH46 strain. Our results also showed that OP46 was less susceptible to the antimonials. In addition, miR-122 and miR-155 expression was evaluated in the liver and J774 macrophages, and in spleens from infected animals, respectively. An increase was observed in the expression of miR-155 in J774 macrophages infected with both strains compared to uninfected cells, with a higher expression in cells infected with OP46. However, no difference in the expression of miR-122 and miR-155 was observed in the infected animals. Thus, this study shows that OP46 was more infective for mice, it caused a higher increase in miR-155 expression in infected macrophages and was less susceptible to the antimonials evaluated. These data suggest that alteration in miR-155 level likely plays a role in regulating the response to L. infantum.

Topics: Animals; Antimony Potassium Tartrate; Antiparasitic Agents; Bone Marrow; Disease Models, Animal; Dogs; Female; Gene Expression Profiling; Humans; Leishmania infantum; Leishmaniasis, Visceral; Liver; Macrophages; Meglumine; Meglumine Antimoniate; Mice; Mice, Inbred BALB C; MicroRNAs; Organometallic Compounds; Parasite Load; Spleen

The aim of this study was to evaluate the susceptibility to anti-leishmanial agents of 24 strains isolated from dogs living in the urban area of Alger lacking drug selection pressure. Two different Leishmania infantum zymodemes, MON-1 and MON-281, were identified in these dogs. The in vitro susceptibility to the main forms of antimonial and amphotericin were assessed on promastigote and amastigote life stages in culture. The results obtained for both parasite life stages were concordant whatever the molecule tested. Moreover, our data showed that isolates belonging to the relatively rare zymodeme of L. infantum, MON-281, were less susceptible to antimony than MON-1, when at the same time there was no significant difference for amphotericin B.

Topics: Algeria; Amphotericin B; Animals; Antimony Potassium Tartrate; Antiprotozoal Agents; Dog Diseases; Dogs; Dose-Response Relationship, Drug; Drug Resistance; Leishmania infantum; Leishmaniasis, Visceral; Meglumine; Meglumine Antimoniate; Organometallic Compounds

Nitric oxide (NO) has been demonstrated to be a principal effector molecule responsible for mediating intracellular killing of Leishmania parasites, the causative organism of leishmaniasis. As measurement of intracellular NO remains a challenge to biologists, we have developed a flow cytometric approach to perform real time biological detection of NO within Leishmania parasites and parasitized macrophages using a membrane permeable derivative of diaminofluorescein [4,5-diaminofluorescein diacetate (DAF-2DA)]. Initially, assay optimization was performed in Leishmania donovani promastigotes, assay specificity being confirmed using both a NO donor [S-nitroso-N-acetyl-penicillamine (SNAP)] and a NO scavenger [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, C-PTIO]. Using 40 μM DAF-2DA, basal levels of intracellular NO were measured which varied in different Leishmania species; addition of conventional anti-leishmanial drugs, antimony and miltefosine translated into a dramatic increase in DAF-2T fluorescence. Furthermore, the assay also measured levels of NO in macrophages, but needed a 20 fold lower concentration of DAF-2DA, being 2 μM. Following parasitization, levels of NO decreased which was normalized following treatment with anti-leishmanial drugs. Similarly monocytes of patients with visceral leishmaniasis at disease presentation showed decreased levels of NO which too reverted on completion of treatment. Taken together, this study opens new perspectives of research regarding monocyte function and provides a real time approach for monitoring the effect of anti-leishmanial compounds.

Topics: Adolescent; Adult; Aged; Animals; Antimony Potassium Tartrate; Antiprotozoal Agents; Benzoates; Female; Flow Cytometry; Fluorescein; Humans; Imidazoles; In Vitro Techniques; Leishmania; Leishmaniasis, Visceral; Macrophages, Peritoneal; Male; Mice; Mice, Inbred BALB C; Middle Aged; Monocytes; Nitric Oxide; Phosphorylcholine; Species Specificity; Young Adult

Resistance to treatment is a growing problem in efforts to control Old World leishmaniasis. Parasites resistant to new therapeutics such as miltefosine have not been reported from the field yet but based on experimental evidence, may appear soon. Therefore, we attempted to identify genetic markers that may correlate with miltefosine resistance. Using a functional cloning approach, we have isolated a gene from Leishmania infantum that, upon over-expression, confers protection not only against miltefosine, but also against Sb(III), the active principle of anti-leishmanial antimonials. The gene encodes a very large putative polypeptide of 299 kDa that shows no similarities to known proteins or functional motifs. Database mining and karyotyping experiments suggest that in L. infantum this gene is part of a 44-kbp duplicated region that is found on two separate chromosomes, CHR08 and CHR29.

Topics: Animals; Antimony Potassium Tartrate; Cosmids; Drug Resistance; Leishmania infantum; Leishmaniasis, Visceral; Phosphorylcholine; Protozoan Proteins; Reverse Transcriptase Polymerase Chain Reaction

Topics: Animals; Antimony; Antimony Potassium Tartrate; Antimony Sodium Gluconate; Dose-Response Relationship, Drug; Gluconates; Leishmaniasis, Visceral; Liposomes; Mice