OBJECTIVES: This study evaluated the implications of clinically acquired miltefosine resistance (MIL-R) by assessing virulence in mice and sand flies to reveal the potential of MIL-R strains to circulate. METHODS: Experimental infections with the MIL-R clinical Leishmania infantum isolate MHOM/FR/2005/LEM5159, having a defect in the LiROS3 subunit of the MIL-transporter, and its syngeneic experimentally reconstituted MIL-S counterpart (LEM5159LiROS3) were performed in BALB/c mice and Lutzomyia longipalpis and Phlebotomus perniciosus sand flies. In mice, the amastigote burdens in liver and spleen were compared microscopically using Giemsa smears and by bioluminescent imaging. During the sand fly infections, the percentage of infected flies, parasite load, colonization of the stomodeal valve and metacyclogenesis were evaluated. The stability of the MIL-R phenotype after sand fly and mouse passage was determined as well. RESULTS: The fitness of the MIL-R strain differed between the mouse and sand fly infection model. In mice, a clear fitness loss was observed compared to the LiROS3-reconstituted susceptible strain. This defect could be rescued by episomal reconstitution with a wildtype LiROS3 copy. However, this fitness loss was not apparent in the sand fly vector, resulting in metacyclogenesis and efficient colonization of the stomodeal valve. Resistance was stable after passage in both sand fly and mouse. CONCLUSION: The natural MIL-R strain is significantly hampered in its ability to multiply and cause a typical visceral infection pattern in BALB/c mice. However, this LiROS3-deficient strain efficiently produced mature infections and metacyclic promastigotes in the sand fly vector highlighting the transmission potential of this particular MIL-R clinical Leishmania strain.

• MeSH
• antiprotozoální látky farmakologie   MeSH
• fosforylcholin analogy a deriváty   farmakologie   MeSH
• hmyz - vektory parazitologie   MeSH
• Leishmania infantum * účinky léků   genetika   patogenita   MeSH
• leishmanióza viscerální farmakoterapie   patologie   MeSH
• léková rezistence genetika   MeSH
• membránové transportní proteiny genetika   MeSH
• myši inbrední BALB C parazitologie   MeSH
• myši MeSH
• Phlebotomus parazitologie   MeSH
• protozoální geny MeSH
• Psychodidae parazitologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: To gain insight into the propagation of miltefosine (MIL) resistance in visceral leishmaniasis, this laboratory study explored development of resistant parasites with a defective miltefosine transporter (MT) in sand flies. METHODS: Infectivity, colonization of stomodeal valve and metacyclogenesis of a MIL-resistant (MIL-R) Leishmania infantum LEM3323 line with a defective MT were assessed in the natural sand fly vectors Phlebotomus perniciosus and Lutzomyia longipalpis. Given our recent description of partial drug dependency of the MT-deficient line, the impact of MIL pre-exposure on sand fly infectivity was explored as well. RESULTS: A significant reduction in sand fly infection, stomodeal valve colonization and differentiation into metacyclics (determined by a lower flagellum/cell body length ratio) was observed in both vectors for MIL-R as compared to the isogenic parent MIL-susceptible line. Re-introduction of the wildtype MT gene into MIL-R tended to partially rescue the capacity to infect sand flies. Pre-exposure to MIL did not alter infectivity of the MIL-R line. CONCLUSION: The MIL resistant L. infantum LEM3323 line is significantly hampered in its development and transmissibility potential in two sand fly vector species. Additional studies are warranted to evaluate whether this applies to other visceral Leishmania parasites with acquired MIL-resistance.

• MeSH
• analýza rozptylu MeSH
• antiprotozoální látky farmakologie   MeSH
• fosforylcholin analogy a deriváty   farmakologie   MeSH
• hmyz - vektory parazitologie   MeSH
• inhibiční koncentrace 50 MeSH
• králíci MeSH
• Leishmania infantum účinky léků   růst a vývoj   MeSH
• leishmanióza viscerální farmakoterapie   parazitologie   přenos   MeSH
• léková rezistence MeSH
• myši inbrední BALB C MeSH
• myši MeSH
• Phlebotomus parazitologie   MeSH
• Psychodidae parazitologie   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The use of plant-derived natural products for the treatment of tropical parasitic diseases often has ethnopharmacological origins. As such, plants grown in temperate regions remain largely untested for novel anti-parasitic activities. We describe here a screen of the PhytoQuest Phytopure library, a novel source comprising over 600 purified compounds from temperate zone plants, against in vitro culture systems for Plasmodium falciparum, Leishmania mexicana, Trypanosoma evansi and T. brucei. Initial screen revealed 6, 65, 15 and 18 compounds, respectively, that decreased each parasite's growth by at least 50% at 1-2 µM concentration. These initial hits were validated in concentration-response assays against the parasite and the human HepG2 cell line, identifying hits with EC50 < 1 μM and a selectivity index of >10. Two sesquiterpene glycosides were identified against P. falciparum, four sterols against L. mexicana, and five compounds of various scaffolds against T. brucei and T. evansi. An L. mexicana resistant line was generated for the sterol 700022, which was found to have cross-resistance to the anti-leishmanial drug miltefosine as well as to the other leishmanicidal sterols. This study highlights the potential of a temperate plant secondary metabolites as a novel source of natural products against tropical parasitic diseases.

• Publikační typ
• časopisecké články MeSH

• MeSH
• esenciální léky aplikace a dávkování   MeSH
• informační služby o lécích MeSH
• receptáře jako téma normy   MeSH
• spotřeba léčiv MeSH

• Konspekt
• Farmacie. Farmakologie
• NLK Publikační typ
• publikace WHO

Context C-6-Geranylated flavonoids possess promising biological activities. These substances could be a source of lead compounds for the development of therapeutics. Objective The study was designed to evaluate their antibacterial and antileishmanial activity. Materials and methods C-6-Geranylated flavanones were tested in micromolar concentrations against promastigote forms of Leishmania brazilensis, L. donovani, L. infantum, and L. panamensis against methicillin-resistant Staphylococcus aureus (MRSA); and synergistic potential with antibiotics was analyzed. IC50 values (after 72 h) were calculated and compared with that of miltefosine. Flow cytometry and DNA fragmentation analysis were used the mechanism of the effect. Geranylated flavanones or epigallocatechin gallate were combined with oxacillin, tetracycline, and ciprofloxacin, and the effects of these two-component combinations were evaluated. Minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) were established (after 24 h), the synergy was measured by the checkerboard titration technique, and the sums of the fractional inhibitory concentrations (∑FICs) were computed. Results 3'-O-Methyl-5'-O-methyldiplacone and 3'-O-methyldiplacone showed good antileishmanial activities (IC50 8-42 μM). 3'-O-Methyl-5'-hydroxydiplacone activates the apoptotic death at leishmanias, the effect of 3'-O-methyl-5'-O-methyldiplacone has another mechanism. The test of the antibacterial activity showed good effects of 3'-O-methyldiplacol and mimulone against MRSA (MIC 2-16 μg/mL), and in six cases, the results showed synergistic effects when combined with oxacillin. Synergistic effects were also found for the combination of epigallocatechin gallate with tetracycline or oxacillin. Conclusion This work demonstrates anti-MRSA and antileishmanial potential of geranylated flavanones and uncovers their promising synergistic activities with antibiotics. In addition, the mechanism of antileishmanial effect is proposed.

• MeSH
• antibakteriální látky izolace a purifikace   farmakologie   MeSH
• antiparazitární látky izolace a purifikace   farmakologie   MeSH
• apoptóza účinky léků   MeSH
• časové faktory MeSH
• flavonoidy izolace a purifikace   farmakologie   MeSH
• fytoterapie MeSH
• léčivé rostliny MeSH
• Leishmania účinky léků   růst a vývoj   MeSH
• Magnoliopsida * chemie   MeSH
• methicilin rezistentní Staphylococcus aureus účinky léků   růst a vývoj   MeSH
• mikrobiální testy citlivosti MeSH
• ovoce MeSH
• prenylace MeSH
• rostlinné extrakty izolace a purifikace   farmakologie   MeSH
• synergismus léků MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH