ABSTRACT
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.
Subject(s)
DNA, Kinetoplast , Leishmaniasis, Visceral , RNA, Spliced Leader , Humans , Leishmaniasis, Visceral/diagnosis , Leishmaniasis, Visceral/drug therapy , Leishmaniasis, Visceral/parasitology , DNA, Kinetoplast/genetics , RNA, Spliced Leader/genetics , RNA, Spliced Leader/metabolism , RNA, Protozoan/genetics , RNA, Protozoan/analysis , Animals , Leishmania/genetics , Antiprotozoal Agents/therapeutic use , BiomarkersABSTRACT
Leishmaniasis is a collection of diseases caused by more than 20 Leishmania parasite species that manifest as either visceral, cutaneous, or mucocutaneous leishmaniasis. Despite the significant mortality and morbidity associated with leishmaniasis, it remains a neglected tropical disease. Existing treatments have variable efficacy, significant toxicity, rising resistance, and limited oral bioavailability, which necessitates the development of novel and affordable therapeutics. Here, we report on the continued optimization of a series of imidazopyridines for visceral leishmaniasis and a scaffold hop to a series of substituted 2-(pyridin-2-yl)-6,7-dihydro-5H-pyrrolo[1,2-a]imidazoles with improved absorption, distribution, metabolism, and elimination properties.