title: Lactate as a novel quantitative measure of viability in Schistosoma mansoni drug sensitivity assays.
abstract: Whole-organism compound sensitivity assays are a valuable strategy in infectious diseases to identify active molecules. In schistosomiasis drug discovery, larval-stage Schistosoma allows the use of a certain degree of automation in the screening of compounds. Unfortunately, the throughput is limited, as drug activity is determined by manual assessment of Schistosoma viability by microscopy. To develop a simple and quantifiable surrogate marker for viability, we targeted glucose metabolism, which is central to Schistosoma survival. Lactate is the end product of glycolysis in human Schistosoma stages and can be detected in the supernatant. We assessed lactate as a surrogate marker for viability in Schistosoma drug screening assays. We thoroughly investigated parameters of lactate measurement and performed drug sensitivity assays by applying schistosomula and adult worms to establish a proof of concept. Lactate levels clearly reflected the viability of schistosomula and correlated with schistosomulum numbers. Compounds with reported potencies were tested, and activities were determined by lactate assay and by microscopy. We conclude that lactate is a sensitive and simple surrogate marker to be measured to determine Schistosoma viability in compound screening assays. Low numbers of schistosomula and the commercial availability of lactate assay reagents make the assay particularly attractive to throughput approaches. Furthermore, standardization of procedures and quantitative evaluation of compound activities facilitate interassay comparisons of potencies and, thus, concerted drug discovery approaches.
authors.affiliation: Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Howe
authors.affiliation: Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.
authors.forename: Dorina
authors.initials: D
authors.lastname: Zöphel
authors.affiliation: Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.
authors.forename: Harini
authors.initials: H
authors.lastname: Subbaraman
authors.affiliation: Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.
authors.forename: Clemens
authors.initials: C
authors.lastname: Unger
authors.affiliation: Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.
authors.forename: Jana
authors.initials: J
authors.lastname: Held
authors.affiliation: Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Engleitner
authors.affiliation: Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany.
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Hoffmann
authors.affiliation: Institut für Tropenmedizin, Eberhard Karls Universität Tübingen, Tübingen, Germany Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon andrea.kreidenweiss@uni-tuebingen.de.
authors.forename: Andrea
authors.initials: A
authors.lastname: Kreidenweiss
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical; D019344:Lactic Acid / Q000032:analysis / Q000378:metabolism*; D008853:Microscopy; D012550:Schistosoma mansoni / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D000871:Anthelmintics; D019344:Lactic Acid