Updating the modified Thompson test by using whole-body bioluminescence imaging to replace traditional efficacy testing in experimental models of murine malaria

Abstract

Background Rodent malaria models are extensively used to predict treatment outcomes in human infections. There is a constant need to improve and refine these models by innovating ways to apply new scientific findings and cutting edge technologies. In addition, and in accordance with the three R’s of animal use in research, in vivo studies should be constantly refined to avoid unnecessary pain and distress to the experimental animals by using preemptive euthanasia as soon as the main scientific study objective has been accomplished. Methods The new methodology described in this manuscript uses the whole-body bioluminescence signal emitted by transgenic, luciferase-expressing Plasmodium berghei parasites to assess the parasite load predicted parasitaemia (PLPP) in drug and control treated female ICR-CD1 mice infected with 1 × 10 5 luciferase-expressing P. berghei (ANKA strain) infected erythrocytes. This methodology can replace other time-consuming and expensive methods that are routinely used to measure parasitaemia in infected animals, such as Giemsa-stained thin blood smears and flow cytometry. Results There is a good correlation between whole-body bioluminescence signal and parasitaemia measured using Giemsa-stained thin blood smears and flow cytometry respectively in donor and study mice in the modified Thompson test. The algebraic formulas which represent these correlations can be successfully used to assess PLPP in donor and study mice. In addition, the new methodology can pinpoint sick animals 2–8 days before they would have been otherwise diagnosed based on behavioural or any other signs of malaria disease. Conclusions The new method for predicting parasitaemia in the modified Thompson test is simple, precise, objective, and minimizes false positive results that can lead to the premature removal of animals from study. Furthermore, from the animal welfare perspective of replace, reduce, and refine, this new method facilitates early removal of sick animals from study as soon as the study objective has been achieved, in many cases well before the clinical signs of disease are present. Electronic supplementary material The online version of this article (10.1186/s12936-019-2661-x) contains supplementary material, which is available to authorized users.

Torin 2 Derivative, NCATS-SM3710, Has Potent Multistage Antimalarial Activity through Inhibition of P. falciparum Phosphatidylinositol 4-Kinase (Pf PI4KIIIβ)

“…Treatments included the administration of a single dose of NCATS-SM3710 (40 mg/kg) on day −1, day 0, or day 1 postinfection, or a dose of NCATS-SM3710 (5 or 10 mg/kg), 4-methyl-primaquine (5 mg/kg), or vehicle control (70% PEG3000, 10% ethanol, 20% water) on days −1, 0, and 1 postinfection. Bioluminescence was measured 1, 2, and 3 days postinfection using a Spectrum In vivo Imaging System (IVIS) (PerkinElmer) . Ten minutes before IVIS analysis the mice received an intraperitoneal (IP) injection of luciferin (200 mg/kg) (Xenogen Corporation).…”

“…Bioluminescence was measured 1, 2, and 3 days postinfection using a Spectrum In vivo Imaging System (IVIS) (PerkinElmer). 33 Ten minutes before IVIS analysis the mice received an intraperitoneal (IP) injection of luciferin (200 mg/ kg) (Xenogen Corporation). The mice were then anaesthetized in a 2.5% isoflurane atmosphere (MWI Veterinary Supply) for 5 min and placed in the imaging chamber for analysis.…”

Liver-targeted polymeric prodrugs delivered subcutaneously improve tafenoquine therapeutic window for malaria radical cure

“…The P. berghei luciferase and blood parasitemia model has been used extensively to characterize TQ activity and to screen for alternative 8-AQ drug candidates (Fig. 3A) ( 62 , 63 ). P. vivax does not infect rodent models, but a model of acute infection using P. berghei that monitors liver sterilization of sporozoites has proven useful for evaluation of new antimalarial drug candidates, and, accordingly, the model has become an industry standard for evaluation of compounds with hypnozoiticidal potential.…”

Screening Marine Natural Products for New Drug Leads against Trypanosomatids and Malaria

“…Several HTS methods have been employed to screen compound libraries against blood stages of the malaria parasite [241]. These methods include DNA-binding fluorescent dyes [242], the parasite lactate dehydrogenase assay methods [243] or the use of transgenic parasites expressing luciferase-reporter cassettes [244][245][246][247]. The SYBR ® green fluorescence-based screening with blood stage P. falciparum cultures has been the hallmark of antimalarial drug discovery for more than a decade [248].…”

“…Transgenic P. falciparum cell lines with stable high-level firefly luciferase expression have been employed for high throughput antimalarial screening [256,257]. The stable luciferase-expressing cell lines of P. berghei have also been employed for noninvasive whole mouse imaging and in vivo antimalarial screening [247,257]. A simple one-step technique based on RNA dye growth inhibition and high-content imaging assay has been developed for antimalarial HTS [258].…”