RESUMO
Accurate detection of viable Leishmania parasites is critical for evaluating visceral leishmaniasis (VL) treatment response at an early timepoint. We compared the decay of kinetoplast DNA (kDNA) and spliced-leader RNA (SL-RNA) in vitro, in vivo, and in a VL patient cohort. An optimized combination of blood preservation and nucleic acid extraction improved efficiency for both targets. SL-RNA degraded more rapidly during treatment than kDNA, and correlated better with microscopic examination. SL-RNA quantitative polymerase chain reaction emerges as a superior method for dynamic monitoring of viable Leishmania parasites. It enables individualized treatment monitoring for improved prognoses and has potential as an early surrogate endpoint in clinical trials.
Assuntos
DNA de Cinetoplasto , Leishmaniose Visceral , RNA Líder para Processamento , Humanos , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/tratamento farmacológico , Leishmaniose Visceral/parasitologia , DNA de Cinetoplasto/genética , RNA Líder para Processamento/genética , RNA Líder para Processamento/metabolismo , RNA de Protozoário/genética , RNA de Protozoário/análise , Animais , Leishmania/genética , Antiprotozoários/uso terapêutico , BiomarcadoresRESUMO
The bioluminescent Leishmania infantum BALB/c mouse model was used to evaluate the parasiticidal drug action kinetics of the reference drugs miltefosine, paromomycin, sodium stibogluconate, and liposomal amphotericin B. Infected mice were treated for 5 days starting from 7 days post-infection, and parasite burdens were monitored over time via bioluminescence imaging (BLI). Using nonlinear regression analyses of the BLI signal, the parasite elimination half-life (t1/2) in the liver, bone marrow, and whole body was determined and compared for the different treatment regimens. Significant differences in parasiticidal kinetics were recorded. A single intravenous dose of 0.5 mg/kg liposomal amphotericin B was the fastest acting with a t1/2 of less than 1 day. Intraperitoneal injection of paromomycin at 320 mg/kg for 5 days proved to be the slowest with a t1/2 of about 5 days in the liver and 16 days in the bone marrow. To conclude, evaluation of the cidal kinetics of the different antileishmanial reference drugs revealed striking differences in their parasite elimination half-lives. This BLI approach also enables an in-depth pharmacodynamic comparison between novel drug leads and may constitute an essential tool for the design of potential drug combinations.