IN VITRO ANTIMALARIAL DRUG SUSCEPTIBILITY AND PFCRT MUTATION AMONG FRESH PLASMODIUM FALCIPARUM ISOLATES FROM THE LAO PDR (LAOS)

Verapamil, was assayed to record its modulating effect upon Brazilian Plasmodium falciparum isolates resistant to chloroquine. Other cardiovascular drugs known to be modulating agents in resistant malaria and/or multidrug-resistant neoplasias, including nifedipine, nitrendipine, diltiazem and propranolol, were also evaluated. Concentrations similar to those for cardiovascular therapy were used in the in vitro microtechnique for antimalarial drug susceptibility. Intrinsic antiplasmodial activity was observed from the lowest concentrations without a significant modulating action. Other reported modulating agents, such as the antipsychotic drug trifluoperazine and the antidepressants desipramine and imipramine, demonstrated similar responses under the same experimental conditions. Results suggest a much higher susceptibility of Brazilian strains, as well as an indifferent behaviour in relation to modulating agents.

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A PILOT FIELD SURVEY ON THE IN VITRO DRUG SUSCEPTIBILITY OF PLASMODIUM FALCIPARUM IN LAO PDR

Tropical Medicine and Health ◽

10.2149/tmh.33.103 ◽

2005 ◽

Vol 33 (2) ◽

pp. 103-104

Author(s):

TOSHIMITSU HATABU ◽

VIENGXAY VANISAVETH ◽

NAO TAGUCHI ◽

JUN KOBAYASHI ◽

M. KAIISSAR MANNOOR ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Field Survey ◽

Lao Pdr ◽

Drug Susceptibility ◽

In Vitro Drug Susceptibility

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Use of Non-Human Plasma for in Vitro Cultivation and Antimalarial Drug Susceptibility Testing of Plasmodium Falciparum

American Journal of Tropical Medicine and Hygiene ◽

10.4269/ajtmh.1985.34.209 ◽

1985 ◽

Vol 34 (2) ◽

pp. 209-215 ◽

Cited By ~ 6

Author(s):

Ayoade M. J. Oduola ◽

Robert E. Desjardins ◽

Bruce M. Alexander ◽

Norman F. Weatherly ◽

Jean H. Bowdre

Keyword(s):

Plasmodium Falciparum ◽

Human Plasma ◽

Antimalarial Drug ◽

Susceptibility Testing ◽

Drug Susceptibility ◽

Drug Susceptibility Testing ◽

In Vitro Cultivation

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Assessment of the Drug Susceptibility of Plasmodium falciparum Clinical Isolates from Africa by Using a Plasmodium Lactate Dehydrogenase Immunodetection Assay and an Inhibitory Maximum Effect Model for Precise Measurement of the 50-Percent Inhibitory Concentration

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00367-06 ◽

2006 ◽

Vol 50 (10) ◽

pp. 3343-3349 ◽

Cited By ~ 61

Author(s):

Halima Kaddouri ◽

Serge Nakache ◽

Sandrine Houzé ◽

France Mentré ◽

Jacques Le Bras

Keyword(s):

Drug Resistance ◽

Plasmodium Falciparum ◽

Lactate Dehydrogenase ◽

Active Metabolite ◽

Inhibitory Concentration ◽

Drug Susceptibility ◽

Maximum Effect ◽

Malaria Parasites ◽

Effect Model

ABSTRACT The extension of drug resistance among malaria-causing Plasmodium falciparum parasites in Africa necessitates implementation of new combined therapeutic strategies. Drug susceptibility phenotyping requires precise measurements. Until recently, schizont maturation and isotopic in vitro assays were the only methods available, but their use was limited by technical constraints. This explains the revived interest in the development of replacement methods, such as the Plasmodium lactate dehydrogenase (pLDH) immunodetection assay. We evaluated a commercially controlled pLDH enzyme-linked immunosorbent assay (ELISA; the ELISA-Malaria antigen test; DiaMed AG, Cressier s/Morat, Switzerland) to assess drug susceptibility in a standard in vitro assay using fairly basic laboratory equipment to study the in vitro resistance of malaria parasites to major antimalarials. Five Plasmodium falciparum clones and 121 clinical African isolates collected during 2003 and 2004 were studied by the pLDH ELISA and the [8-3H]hypoxanthine isotopic assay as a reference with four antimalarials. Nonlinear regression with a maximum effect model was used to estimate the 50% inhibitory concentration (IC50) and its confidence intervals. The two methods were observed to have similar reproducibilities, but the pLDH ELISA demonstrated a higher sensitivity. The high correlation (r = 0.98) and the high phenotypic agreement (κ = 0.88) between the two methods allowed comparison by determination of the IC50s. Recently collected Plasmodium falciparum African isolates were tested by pLDH ELISA and showed drug resistance or decreased susceptibilities of 62% to chloroquine and 11.5% to the active metabolite of amodiaquine. No decreased susceptibility to lumefantrine or the active metabolite of artemisinin was detected. The availability of this simple and highly sensitive pLDH immunodetection assay will provide an easier method for drug susceptibility testing of malaria parasites.

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World Antimalarial Resistance Network (WARN) II: In vitro antimalarial drug susceptibility

Malaria Journal ◽

10.1186/1475-2875-6-120 ◽

2007 ◽

Vol 6 (1) ◽

Cited By ~ 39

Author(s):

David J Bacon ◽

Ronan Jambou ◽

Thierry Fandeur ◽

Jacques Le Bras ◽

Chansuda Wongsrichanalai ◽

...

Keyword(s):

Antimalarial Drug ◽

Drug Susceptibility ◽

Resistance Network ◽

Antimalarial Resistance

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Modulating effects of plasma containing anti-malarial antibodies on in vitro anti-malarial drug susceptibility in Plasmodium falciparum

Malaria Journal ◽

10.1186/1475-2875-9-326 ◽

2010 ◽

Vol 9 (1) ◽

pp. 326 ◽

Cited By ~ 3

Author(s):

Preeyaporn Monatrakul ◽

Mathirut Mungthin ◽

Arjen M Dondorp ◽

Srivicha Krudsood ◽

Rachanee Udomsangpetch ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Drug Susceptibility

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Piperaquine resistant Cambodian Plasmodium falciparum clinical isolates: in vitro genotypic and phenotypic characterization

10.21203/rs.3.rs-22444/v3 ◽

2020 ◽

Author(s):

Nonlawat Boonyalai ◽

Brian A Vesely ◽

Chatchadaporn Thamnurak ◽

Chantida Praditpol ◽

Watcharintorn Fagnark ◽

...

Keyword(s):

Drug Resistance ◽

Plasmodium Falciparum ◽

Copy Number ◽

Drug Susceptibility ◽

Antagonistic Activity ◽

Drug Combinations ◽

Chloroquine Resistance ◽

Phenotypic Characterization ◽

Field Isolates

Abstract Background High rates of dihydroartemisinin-piperaquine (DHA-PPQ) treatment failures have been documented for uncomplicated Plasmodium falciparum in Cambodia. The genetic markers plasmepsin 2 ( pfpm2 ), exonuclease ( pfexo ) and chloroquine resistance transporter ( pfcrt ) genes are associated with PPQ resistance and are used for monitoring the prevalence of drug resistance and guiding malaria drug treatment policy.Methods To examine the relative contribution of each marker to PPQ resistance, in vitro culture and the PPQ survival assay were performed on seventeen P. falciparum isolates from northern Cambodia, and the presence of E415G-Exo and pfcrt mutations (T93S, H97Y, F145I, I218F, M343L, C350R, and G353V) as well as pfpm2 copy number polymorphisms were determined. Parasites were then cloned by limiting dilution and the cloned parasites were tested for drug susceptibility. Isobolographic analysis of several drug combinations for standard clones and newly cloned P. falciparum Cambodian isolates was also determined.Results The characterization of culture-adapted isolates revealed that the presence of novel pfcrt mutations (T93S, H97Y, F145I, and I218F) with E415G-Exo mutation can confer PPQ-resistance, in the absence of pfpm2 amplification. In vitro testing of PPQ resistant parasites demonstrated a bimodal dose-response, the existence of a swollen digestive vacuole phenotype, and an increased susceptibility to quinine, chloroquine, mefloquine and lumefantrine. To further characterize drug sensitivity, parental parasites were cloned in which a clonal line, 14-B5, was identified as sensitive to artemisinin and piperaquine, but resistant to chloroquine. Assessment of the clone against a panel of drug combinations revealed antagonistic activity for six different drug combinations. However, mefloquine-proguanil and atovoquone-proguanil combinations revealed synergistic antimalarial activity.Conclusions Surveillance for PPQ resistance in regions relying on DHA-PPQ as the first-line treatment is dependent on the monitoring of molecular markers of drug resistance. P. falciparum harbouring novel pfcrt mutations with E415G-exo mutations displayed PPQ resistant phenotype. The presence of pfpm2 amplification was not required to render parasites PPQ resistant suggesting that the increase in pfpm2 copy number alone is not the sole modulator of PPQ resistance. Genetic background of circulating field isolates appear to play a role in drug susceptibility and biological responses induced by drug combinations. The use of latest field isolates may be necessary for assessment of relevant drug combinations against P. falciparum strains and when down-selecting novel drug candidates.

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A Chemical Rescue Screen Identifies a Plasmodium falciparum Apicoplast Inhibitor Targeting MEP Isoprenoid Precursor Biosynthesis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.03342-14 ◽

2014 ◽

Vol 59 (1) ◽

pp. 356-364 ◽

Cited By ~ 52

Author(s):

Wesley Wu ◽

Zachary Herrera ◽

Danny Ebert ◽

Katie Baska ◽

Seok H. Cho ◽

...

Keyword(s):

Plasmodium Falciparum ◽

Antimalarial Drug ◽

Drug Targets ◽

Specific Activity ◽

Drug Candidate ◽

Content Type ◽

Chemical Rescue ◽

Growth Inhibitory ◽

Parasite Populations

ABSTRACTThe apicoplast is an essential plastid organelle found inPlasmodiumparasites which contains several clinically validated antimalarial-drug targets. A chemical rescue screen identified MMV-08138 from the “Malaria Box” library of growth-inhibitory antimalarial compounds as having specific activity against the apicoplast. MMV-08138 inhibition of blood-stagePlasmodium falciparumgrowth is stereospecific and potent, with the most active diastereomer demonstrating a 50% effective concentration (EC50) of 110 nM. Whole-genome sequencing of 3 drug-resistant parasite populations from two independent selections revealed E688Q and L244I mutations inP. falciparumIspD, an enzyme in the MEP (methyl-d-erythritol-4-phosphate) isoprenoid precursor biosynthesis pathway in the apicoplast. The active diastereomer of MMV-08138 directly inhibited PfIspD activityin vitrowith a 50% inhibitory concentration (IC50) of 7.0 nM. MMV-08138 is the first PfIspD inhibitor to be identified and, together with heterologously expressed PfIspD, provides the foundation for further development of this promising antimalarial drug candidate lead. Furthermore, this report validates the use of the apicoplast chemical rescue screen coupled with target elucidation as a discovery tool to identify specific apicoplast-targeting compounds with new mechanisms of action.

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Growth, Drug Susceptibility, and Gene Expression Profiling of Plasmodium falciparum Cultured in Medium Supplemented with Human Serum

CrossRef Listing of Deleted DOIs ◽

10.1177/1087057107310638 ◽

2007 ◽

Vol 12 (8) ◽

pp. 1109-1114 ◽

Cited By ~ 14

Author(s):

Kshipra Singh ◽

Ameeta Agarwal ◽

Shabana I. Khan ◽

Larry A. Walker ◽

Babu L. Tekwani

Keyword(s):

Gene Expression ◽

Plasmodium Falciparum ◽

Human Serum ◽

Global Gene Expression ◽

Drug Susceptibility ◽

Growth Cycle ◽

In Vitro Cultivation ◽

Human Malaria Parasite ◽

In Vitro Drug Susceptibility

In vitro cultivation of Plasmodium falciparum has been extremely useful in understanding the biology of the human malaria parasite as well as research on the discovery of new antimalarial drugs and vaccines. A chemically defined serum-free medium supplemented with lipid-rich bovine serum albumin (AlbuMAX I) offers the following advantages over human serum-supplemented media for the in vitro culture of P. falciparum: 1) improved growth profile, with more than a 2-fold higher yield of the parasites at any stage of the growth cycle; 2) suitability for in vitro antimalarial screening, as the parasites grown in AlbuMAX and human serum-supplemented media show similar sensitivity to standard and novel antimalarials as well as natural product extracts in the in vitro drug susceptibility assays; and 3) DNA microarray analysis comparing the global gene expression profile of sorbitol-synchronized P. falciparum trophozoites grown in the 2 different media, indicating minimal differences. ( Journal of Biomolecular Screening 2007:1109-1114)

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