Plasmodium falciparum assocation study of artemisinin resistance
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ABSTRACT:
ORGANISM(S): Plasmodium falciparum
PROVIDER: GSE56390 | GEO | 2014/05/28
SECONDARY ACCESSION(S): PRJNA243263
REPOSITORIES: GEO
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Project description:A testing association of parasite genotypes with clinical resistance phenotype. Submission of genotypes from all microarray genotyped samples Comparison of DNA from clinical isolates and generated by next-generation sequencing with prolonged clearance half-life
2014-05-28 | E-GEOD-56390 | biostudies-arrayexpress
Project description:A genome wide association study (GWAS) testing association of parasite genotypes with clinically decreased piperaquine sensitivity phenotype Submission of genotypes from all microarray genotyped samples
2017-12-28 | GSE100704 | GEO
Project description:The role of extracellular vesicles in developing artemisinin resistance in Plasmodium falciparum is not known. We have posited a role for EVs in the development of ARTr (EVs export hypothesis) (Tandoh et al.,2022).The objective of this study was to test a prediction of the EVs export hypothesis to gain insight into a putative role for EVs in the expression of the artemisinin resistant phenotype. We compared the gene expression profile of two artemisinin resistant parasites (C580R and R539T) generated by CRISPR based editing of an artemisinin susceptible parasite (Dd2) for enrichment with an EVs module of interest using gene set enrichment analysis.
2022-09-15 | GSE210644 | GEO
Project description:BackgroundArtemisinin-based combination therapies are the recommended first-line treatments of falciparum malaria in all countries with endemic disease. There are recent concerns that the efficacy of such therapies has declined on the Thai-Cambodian border, historically a site of emerging antimalarial-drug resistance.MethodsIn two open-label, randomized trials, we compared the efficacies of two treatments for uncomplicated falciparum malaria in Pailin, western Cambodia, and Wang Pha, northwestern Thailand: oral artesunate given at a dose of 2 mg per kilogram of body weight per day, for 7 days, and artesunate given at a dose of 4 mg per kilogram per day, for 3 days, followed by mefloquine at two doses totaling 25 mg per kilogram. We assessed in vitro and in vivo Plasmodium falciparum susceptibility, artesunate pharmacokinetics, and molecular markers of resistance.ResultsWe studied 40 patients in each of the two locations. The overall median parasite clearance times were 84 hours (interquartile range, 60 to 96) in Pailin and 48 hours (interquartile range, 36 to 66) in Wang Pha (P<0.001). Recrudescence confirmed by means of polymerase-chain-reaction assay occurred in 6 of 20 patients (30%) receiving artesunate monotherapy and 1 of 20 (5%) receiving artesunate-mefloquine therapy in Pailin, as compared with 2 of 20 (10%) and 1 of 20 (5%), respectively, in Wang Pha (P=0.31). These markedly different parasitologic responses were not explained by differences in age, artesunate or dihydroartemisinin pharmacokinetics, results of isotopic in vitro sensitivity tests, or putative molecular correlates of P. falciparum drug resistance (mutations or amplifications of the gene encoding a multidrug resistance protein [PfMDR1] or mutations in the gene encoding sarco-endoplasmic reticulum calcium ATPase6 [PfSERCA]). Adverse events were mild and did not differ significantly between the two treatment groups.ConclusionsP. falciparum has reduced in vivo susceptibility to artesunate in western Cambodia as compared with northwestern Thailand. Resistance is characterized by slow parasite clearance in vivo without corresponding reductions on conventional in vitro susceptibility testing. Containment measures are urgently needed. (ClinicalTrials.gov number, NCT00493363, and Current Controlled Trials number, ISRCTN64835265.)
| S-EPMC3495232 | biostudies-literature
Project description:A custom resequencing array for analysis of field isolates of plasmdium falciparum was created. Test of DNA with genotypes known at all loci genotyped by the microarray as well as test of accuracy correlation with amounts of DNA added to each array
2014-03-28 | GSE56305 | GEO
Project description:The worldwide use of artemisinin-based combination therapies (ACTs) has contributed in recent years to a substantial reduction in deaths resulting from Plasmodium falciparum malaria. Resistance to artemisinins, however, has emerged in Southeast Asia. Clinically, resistance is defined as a slower rate of parasite clearance in patients treated with an artemisinin derivative or an ACT. These slow clearance rates associate with enhanced survival rates of ring-stage parasites briefly exposed in vitro to dihydroartemisinin. We describe recent progress made in defining the molecular basis of artemisinin resistance, which has identified a primary role for the P. falciparum K13 protein. Using K13 mutations as molecular markers, epidemiological studies are now tracking the emergence and spread of artemisinin resistance. Mechanistic studies suggest potential ways to overcome resistance.
| S-EPMC5007624 | biostudies-literature
Project description:Artemisinin-resistant Plasmodium falciparum malaria has emerged in western Cambodia. Resistance is characterized by prolonged in vivo parasite clearance times (PCTs) following artesunate treatment. The biological basis is unclear. The hypothesis that delayed parasite clearance results from a stage-specific reduction in artemisinin sensitivity of the circulating young asexual parasite ring stages was examined. A mathematical model was developed, describing the intrahost parasite stage-specific pharmacokinetic-pharmacodynamic relationships. Model parameters were estimated using detailed pharmacokinetic and parasite clearance data from 39 patients with uncomplicated falciparum malaria treated with artesunate from Pailin (western Cambodia) where artemisinin resistance was evident and 40 patients from Wang Pha (northwestern Thailand) where efficacy was preserved. The mathematical model reproduced the observed parasite clearance for each patient with an accurate goodness of fit (rmsd: 0.03-0.67 in log(10) scale). The parameter sets that provided the best fits with the observed in vivo data consist of a highly conserved concentration-effect relationship for the trophozoite and schizont parasite stages, but a variable relationship for the ring stages. The model-derived assessment suggests that the efficacy of artesunate on ring stage parasites is reduced significantly in Pailin. This result supports the hypothesis that artemisinin resistance mainly reflects reduced ring-stage susceptibility and predicts that doubling the frequency of dosing will accelerate clearance of artemisinin-resistant parasites.
| S-EPMC3017155 | biostudies-literature
Project description:BackgroundArtemisinin resistance in Plasmodium falciparum has emerged in Southeast Asia and now poses a threat to the control and elimination of malaria. Mapping the geographic extent of resistance is essential for planning containment and elimination strategies.MethodsBetween May 2011 and April 2013, we enrolled 1241 adults and children with acute, uncomplicated falciparum malaria in an open-label trial at 15 sites in 10 countries (7 in Asia and 3 in Africa). Patients received artesunate, administered orally at a daily dose of either 2 mg per kilogram of body weight per day or 4 mg per kilogram, for 3 days, followed by a standard 3-day course of artemisinin-based combination therapy. Parasite counts in peripheral-blood samples were measured every 6 hours, and the parasite clearance half-lives were determined.ResultsThe median parasite clearance half-lives ranged from 1.9 hours in the Democratic Republic of Congo to 7.0 hours at the Thailand-Cambodia border. Slowly clearing infections (parasite clearance half-life >5 hours), strongly associated with single point mutations in the "propeller" region of the P. falciparum kelch protein gene on chromosome 13 (kelch13), were detected throughout mainland Southeast Asia from southern Vietnam to central Myanmar. The incidence of pretreatment and post-treatment gametocytemia was higher among patients with slow parasite clearance, suggesting greater potential for transmission. In western Cambodia, where artemisinin-based combination therapies are failing, the 6-day course of antimalarial therapy was associated with a cure rate of 97.7% (95% confidence interval, 90.9 to 99.4) at 42 days.ConclusionsArtemisinin resistance to P. falciparum, which is now prevalent across mainland Southeast Asia, is associated with mutations in kelch13. Prolonged courses of artemisinin-based combination therapies are currently efficacious in areas where standard 3-day treatments are failing. (Funded by the U.K. Department of International Development and others; ClinicalTrials.gov number, NCT01350856.).
| S-EPMC4143591 | biostudies-literature
Project description:A custom resequencing array for analysis of field isolates of plasmdium falciparum was created. Test of DNA with genotypes known at all loci genotyped by the microarray as well as test of accuracy correlation with amounts of DNA added to each array Comparison of test DNA from lab and clinical isolates between genotyped generated by next-generation sequencing and this new custom DNA microarray.
2014-03-28 | E-GEOD-56305 | biostudies-arrayexpress
Project description:Artemisinin resistance in Plasmodium falciparum malaria has emerged in western Cambodia. This is a major threat to global plans to control and eliminate malaria as the artemisinins are a key component of antimalarial treatment throughout the world. Using DNA microarrays we identify key features of a transcriptional profile that are associated with the delayed parasite clearance phenotype. These include reduced expression of several basic metabolic and cellular pathways in the early stages, and increased expression of essentially all functionalities associated with protein metabolism in the later stages of P. falciparum intraerythrocytic development. This is consistent with the reduced ring stage susceptibility that characterizes artemisinin resistant P. falciparum. This modulation of the P. falciparum intraerythrocytic transcriptome may result from differential expression of several regulatory proteins such as transcription factors of chromatin remodeling associated factors. In addition, the artemisinin resistant phenotype is strongly associated with a specific pattern of copy number variations, some of which are linked with differential expression of several regulatory proteins such as histone 4 and zinc permease. This study reports the first global transcriptional survey of artemisinin resistant parasites and provides a set of candidate genes for further investigation.
2010-12-07 | GSE25879 | GEO