1
|
Fukuda N, Tachibana SI, Ikeda M, Sakurai-Yatsushiro M, Balikagala B, Katuro OT, Yamauchi M, Emoto S, Hashimoto M, Yatsushiro S, Sekihara M, Mori T, Hirai M, Opio W, Obwoya PS, Auma MA, Anywar DA, Kataoka M, Palacpac NMQ, Odongo-Aginya EI, Kimura E, Ogwang M, Horii T, Mita T. Ex vivo susceptibility of Plasmodium falciparum to antimalarial drugs in Northern Uganda. Parasitol Int 2020; 81:102277. [PMID: 33370608 DOI: 10.1016/j.parint.2020.102277] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/10/2020] [Accepted: 12/20/2020] [Indexed: 10/22/2022]
Abstract
In Uganda, artemether-lumefantrine was introduced as an artemisinin-based combination therapy (ACT) for malaria in 2006. We have previously reported a moderate decrease in ex vivo efficacy of lumefantrine in Northern Uganda, where we also detected ex vivo artemisinin-resistant Plasmodium falciparum. Therefore, it is necessary to search for candidate partner alternatives for ACT. Here, we investigated ex vivo susceptibility to four ACT partner drugs as well as quinine and chloroquine, in 321 cases between 2013 and 2018. Drug-resistant mutations in pfcrt and pfmdr1 were also determined. Ex vivo susceptibility to amodiaquine, quinine, and chloroquine was well preserved, whereas resistance to mefloquine was found in 45.8%. There were few cases of multi-drug resistance. Reduced sensitivity to mefloquine and lumefantrine was significantly associated with the pfcrt K76 wild-type allele, in contrast to the association between chloroquine resistance and the K76T allele. Pfmdr1 duplication was not detected in any of the cases. Amodiaquine, a widely used partner drug for ACT in African countries, may be the first promising alternative in case lumefantrine resistance emerges. Therapeutic use of mefloquine may not be recommended in this area. This study also emphasizes the need for sustained monitoring of antimalarial susceptibility in Northern Uganda to develop proper treatment strategies.
Collapse
Affiliation(s)
- Naoyuki Fukuda
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shin-Ichiro Tachibana
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Mie Ikeda
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Miki Sakurai-Yatsushiro
- Department of International Affairs and Tropical Medicine, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Betty Balikagala
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Osbert T Katuro
- Mildmay Uganda, Nazibwa Hill, Lweza, P.O. Box 24985, Kampala, Uganda
| | - Masato Yamauchi
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Sakurako Emoto
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Muneaki Hashimoto
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2217-14, Hayashi-cho, Takamatsu, Kagawa, 761-0301, Japan
| | - Shouki Yatsushiro
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2217-14, Hayashi-cho, Takamatsu, Kagawa, 761-0301, Japan
| | - Makoto Sekihara
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Toshiyuki Mori
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Makoto Hirai
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Walter Opio
- St. Mary's Hospital Lacor, P.O. Box 180, Gulu, Uganda
| | - Paul S Obwoya
- St. Mary's Hospital Lacor, P.O. Box 180, Gulu, Uganda
| | - Mary A Auma
- St. Mary's Hospital Lacor, P.O. Box 180, Gulu, Uganda
| | - Denis A Anywar
- Faculty of Medicine, Gulu University, P.O. Box 166, Gulu, Uganda
| | - Masatoshi Kataoka
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 2217-14, Hayashi-cho, Takamatsu, Kagawa, 761-0301, Japan
| | - Nirianne M Q Palacpac
- Department of Malaria Vaccine Development, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | | | - Eisaku Kimura
- School of Tropical Medicine and Global Health, Nagasaki University, 1-12-4 Sakamoto, Nagasaki, Nagasaki 852-8523, Japan
| | - Martin Ogwang
- St. Mary's Hospital Lacor, P.O. Box 180, Gulu, Uganda
| | - Toshihiro Horii
- Department of Malaria Vaccine Development, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Toshihiro Mita
- Department of Tropical Medicine and Parasitology, School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| |
Collapse
|
2
|
Ungogo MA, Ebiloma GU, Ichoron N, Igoli JO, de Koning HP, Balogun EO. A Review of the Antimalarial, Antitrypanosomal, and Antileishmanial Activities of Natural Compounds Isolated From Nigerian Flora. Front Chem 2020; 8:617448. [PMID: 33425860 PMCID: PMC7786139 DOI: 10.3389/fchem.2020.617448] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/03/2020] [Indexed: 12/16/2022] Open
Abstract
The West African country Nigeria features highly diverse vegetation and climatic conditions that range from rain forest bordering the Atlantic Ocean in the South to the Desert (Sahara) at the Northern extreme. Based on data from the World Conservation Monitoring Center of the United Nations Environmental Protection, Nigeria, with ~5,000 documented vascular plants, ranks amongst the top 50 countries in terms of biodiversity. Such a rich biodiversity implies that the country is rich in diverse secondary metabolites-natural products/unique chemicals produced by the plant kingdom to confer selective advantages to them. Like many tropical countries, Nigeria is also endemic to numerous infectious diseases particularly those caused by parasitic pathogens. These phytochemicals have been exploited for the treatment of diseases and as a result, a new branch of chemistry, natural product chemistry, has evolved, to try to reproduce and improve the therapeutic qualities of particular phytochemicals. In this review, we have compiled a compendium of natural products, isolated from Nigerian flora, that have been reported to be effective against certain protozoan parasites with the aim that it will stimulate interests for further investigations, and give impetus to the development of the natural products into registered drugs. In total 93 structurally characterized natural compounds have been identified with various levels of anti-parasite activity mainly from Nigerian plants. The synthesis protocol and molecular target for some of these natural anti-parasite agents have been established. For instance, the anti-plasmodial compound fagaronine (7), a benzophenanthridine alkaloid from Fagara zanthoxyloides has been successfully synthesized in the laboratory, and the anti-trypanosomal compound azaanthraquinone (55) elicits its effect by inhibiting mitochondrial electron transfer in trypanosomes. This review also discusses the barriers to developing approved drugs from phytochemicals, and the steps that should be taken in order to accelerate the development of new antiparasitics from the highlighted compounds.
Collapse
Affiliation(s)
- Marzuq A. Ungogo
- Department of Veterinary Pharmacology and Toxicology, Ahmadu Bello University, Zaria, Nigeria
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Godwin U. Ebiloma
- School of Health and Life Sciences, Teesside University, Middlesbrough, United Kingdom
| | - Nahandoo Ichoron
- Phytochemistry Research Group, Department of Chemistry, University of Agriculture, Makurdi, Nigeria
| | - John O. Igoli
- Phytochemistry Research Group, Department of Chemistry, University of Agriculture, Makurdi, Nigeria
| | - Harry P. de Koning
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Emmanuel O. Balogun
- Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria
- Africa Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology (ACENTDFB), Ahmadu Bello University, Zaria, Nigeria
| |
Collapse
|
3
|
Cortez-Maya S, Moreno-Herrera A, Palos I, Rivera G. Old Antiprotozoal Drugs: Are They Still Viable Options for Parasitic Infections or New Options for Other Diseases? Curr Med Chem 2020; 27:5403-5428. [DOI: 10.2174/0929867326666190628163633] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/31/2019] [Accepted: 06/10/2019] [Indexed: 01/16/2023]
Abstract
Parasitic diseases, caused by helminths (ascariasis, hookworm, trichinosis, and schistosomiasis)
and protozoa (chagas, leishmaniasis, and amebiasis), are considered a serious public
health problem in developing countries. Additionally, there is a limited arsenal of anti-parasitic
drugs in the current pipeline and growing drug resistance. Therefore, there is a clear need for the
discovery and development of new compounds that can compete and replace these drugs that have
been controlling parasitic infections over the last decades. However, this approach is highly resource-
intensive, expensive and time-consuming. Accordingly, a drug repositioning strategy of the
existing drugs or drug-like molecules with known pharmacokinetics and safety profiles is alternatively
being used as a fast approach towards the identification of new treatments. The artemisinins,
mefloquine, tribendimidine, oxantel pamoate and doxycycline for the treatment of helminths, and
posaconazole and hydroxymethylnitrofurazone for the treatment of protozoa are promising candidates.
Therefore, traditional antiprotozoal drugs, which were developed in some cases decades ago,
are a valid solution. Herein, we review the current status of traditional anti-helminthic and antiprotozoal
drugs in terms of drug targets, mode of action, doses, adverse effects, and parasite resistance
to define their suitability for repurposing strategies. Current antiparasitic drugs are not only
still viable for the treatment of helminth and protozoan infections but are also important candidates
for new pharmacological treatments.
Collapse
Affiliation(s)
- Sandra Cortez-Maya
- Instituto de Quimica, Universidad Nacional Autonoma de Mexico, Cd. Universitaria, Circuito Exterior, Coyoacan, 04510 Ciudad de Mexico, Mexico
| | - Antonio Moreno-Herrera
- Laboratorio de Biotecnologia Farmaceutica, Centro de Biotecnologia Genomica, Instituto Politecnico Nacional, 88710 Reynosa, Mexico
| | - Isidro Palos
- Unidad AcadEmica Multidisciplinaria Reynosa-Rodhe, Universidad AutOnoma de Tamaulipas, 88710 Reynosa, Mexico
| | - Gildardo Rivera
- Laboratorio de Biotecnologia Farmaceutica, Centro de Biotecnologia Genomica, Instituto Politecnico Nacional, 88710 Reynosa, Mexico
| |
Collapse
|
4
|
Martin RE. The transportome of the malaria parasite. Biol Rev Camb Philos Soc 2019; 95:305-332. [PMID: 31701663 DOI: 10.1111/brv.12565] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 12/15/2022]
Abstract
Membrane transport proteins, also known as transporters, control the movement of ions, nutrients, metabolites, and waste products across the membranes of a cell and are central to its biology. Proteins of this type also serve as drug targets and are key players in the phenomenon of drug resistance. The malaria parasite has a relatively reduced transportome, with only approximately 2.5% of its genes encoding transporters. Even so, assigning functions and physiological roles to these proteins, and ascertaining their contributions to drug action and drug resistance, has been very challenging. This review presents a detailed critique and synthesis of the disruption phenotypes, protein subcellular localisations, protein functions (observed or predicted), and links to antimalarial drug resistance for each of the parasite's transporter genes. The breadth and depth of the gene disruption data are particularly impressive, with at least one phenotype determined in the parasite's asexual blood stage for each transporter gene, and multiple phenotypes available for 76% of the genes. Analysis of the curated data set revealed there to be relatively little redundancy in the Plasmodium transportome; almost two-thirds of the parasite's transporter genes are essential or required for normal growth in the asexual blood stage of the parasite, and this proportion increased to 78% when the disruption phenotypes available for the other parasite life stages were included in the analysis. These observations, together with the finding that 22% of the transportome is implicated in the parasite's resistance to existing antimalarials and/or drugs within the development pipeline, indicate that transporters are likely to serve, or are already serving, as drug targets. Integration of the different biological and bioinformatic data sets also enabled the selection of candidates for transport processes known to be essential for parasite survival, but for which the underlying proteins have thus far remained undiscovered. These include potential transporters of pantothenate, isoleucine, or isopentenyl diphosphate, as well as putative anion-selective channels that may serve as the pore component of the parasite's 'new permeation pathways'. Other novel insights into the parasite's biology included the identification of transporters for the potential development of antimalarial treatments, transmission-blocking drugs, prophylactics, and genetically attenuated vaccines. The syntheses presented herein set a foundation for elucidating the functions and physiological roles of key members of the Plasmodium transportome and, ultimately, to explore and realise their potential as therapeutic targets.
Collapse
Affiliation(s)
- Rowena E Martin
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| |
Collapse
|
5
|
Assessment of drug resistance associated genetic diversity in Mauritanian isolates of Plasmodium vivax reveals limited polymorphism. Malar J 2018; 17:416. [PMID: 30409138 PMCID: PMC6225721 DOI: 10.1186/s12936-018-2548-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 10/24/2018] [Indexed: 01/09/2023] Open
Abstract
Background Plasmodium vivax is the predominant malaria species in northern Mauritania. Molecular data on P. vivax isolates circulating in West Africa are scarce. The present study analysed molecular markers associated with resistance to antifolates (Pvdhfr and Pvdhps), chloroquine (Pvmdr1), and artemisinin (Pvk12) in P. vivax isolates collected in two cities located in the Saharan zone of Mauritania. Methods Blood samples were obtained from P. vivax-infected patients recruited for chloroquine therapeutic efficacy study in 2013 and febrile patients spontaneously consulting health facilities in Nouakchott and Atar in 2015–2016. Fragments of Pvdhfr (codons 13, 33, 57, 58, 61, 117, and 174), Pvdhps (codons 382, 383, 512, 553, and 585), Pvmdr1 (codons 976 and 1076) and Pvk12 (codon 552) genes were amplified by PCR and sequenced. Results Most of the isolates in Nouakchott (126/154, 81.8%) and Atar (44/45, 97.8%) carried the wild-type Pvdhfr allelic variant (IPFSTSI). In Nouakchott, all mutants (28/154; 18.2%) had double Pvdhfr mutations in positions 58 and 61 (allelic variant IPFRMSI), whereas in Atar only 1 isolate was mutant (S117N, allelic variant IPFSTNI). The wild-type Pvdhps allelic variant (SAKAV) was found in all tested isolates (Nouakchott, n = 93; Atar, n = 37). Few isolates in Nouakchott (5/115, 4.3%) and Atar (3/79, 3.8%) had the mutant Pvmdr1 allele 976F or 1076L, but not both, including in pre-treatment isolates obtained from patients treated successfully with chloroquine. All isolates (59 in Nouakchott and 48 in Atar) carried the wild-type V552 allele in Pvk12. Conclusions Polymorphisms in Pvdhfr, Pvdhps, Pvmdr1, and Pvk12 were limited in P. vivax isolates collected recently in Nouakchott and Atar. Compared to the isolates collected in Nouakchott in 2007–2009, there was no evidence for selection of mutants. The presence of one, but not both, of the two potential markers of chloroquine resistance in Pvmdr1 in pre-treatment isolates did not influence the clinical outcome, putting into question the role of Pvmdr1 mutant alleles 976F and 1076L in treatment failure. Molecular surveillance is an important component of P. vivax malaria control programme in the Saharan zone of Mauritania to predict possible emergence of drug-resistant parasites.
Collapse
|
6
|
Moore BR, Salman S, Davis TME. Treatment regimens for pregnant women with falciparum malaria. Expert Rev Anti Infect Ther 2016; 14:691-704. [PMID: 27322015 DOI: 10.1080/14787210.2016.1202758] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION With increasing parasite drug resistance, the WHO has updated treatment recommendations for falciparum malaria including in pregnancy. This review assesses the evidence for choice of treatment for pregnant women. AREAS COVERED Relevant studies, primarily those published since 2010, were identified from reference databases and were used to identify secondary data sources. Expert commentary: WHO recommends use of intravenous artesunate for severe malaria, quinine-clindamycin for uncomplicated malaria in first trimester, and artemisinin combination therapy for uncomplicated malaria in second/third trimesters. Because fear of adverse outcomes has often excluded pregnant women from conventional drug development, available data for novel therapies are usually based on preclinical studies and cases of inadvertent exposure. Changes in antimalarial drug disposition in pregnancy have been observed but are yet to be translated into specific treatment recommendations. Such targeted regimens may become important as parasite resistance demands that drug exposure is optimized.
Collapse
Affiliation(s)
- Brioni R Moore
- a Fiona Stanley Hospital Unit, School of Medicine and Pharmacology , University of Western Australia , Perth , Australia.,b School of Pharmacy , Curtin University , Perth , Australia
| | - Sam Salman
- c Linear Clinical Research Limited, QEII Medical Centre , Nedlands , Australia.,d Fremantle Hospital Unit, School of Medicine and Pharmacology , University of Western Australia , Fremantle , Australia
| | - Timothy M E Davis
- d Fremantle Hospital Unit, School of Medicine and Pharmacology , University of Western Australia , Fremantle , Australia
| |
Collapse
|
7
|
Gadalla NB, Tavera G, Mu J, Kabyemela ER, Fried M, Duffy PE, Sá JM, Wellems TE. Prevalence of Plasmodium falciparum anti-malarial resistance-associated polymorphisms in pfcrt, pfmdr1 and pfnhe1 in Muheza, Tanzania, prior to introduction of artemisinin combination therapy. Malar J 2015; 14:129. [PMID: 25890383 PMCID: PMC4392636 DOI: 10.1186/s12936-015-0642-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 03/07/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A report of the chloroquine and amodiaquine resistance pfcrt-SVMNT haplotype in Tanzania raises concern about high-level resistance to the artesunate-amodiaquine combination treatment widely employed in Africa. Mutations in the pfmdr1 multi-drug resistance gene may also be associated with resistance, and a highly polymorphic microsatellite (ms-4760) of the pfnhe1 gene involved in quinine susceptibility has not been surveyed in Tanzania. METHODS A total of 234 samples collected between 2003 - 2006 from an observational birth cohort of young children in Muheza, Tanzania were analysed. In these children, 141 cases of P. falciparum infections were treated with AQ and 93 episodes were treated with QN. Haplotypes of pfcrt and pfmdr1 were determined by a Taqman assay, and ms-4760 repeats in pfnhe1 were assessed by nested PCR amplification and direct sequencing. Parasite population diversity was evaluated using microsatellite markers on five different chromosomes. RESULTS The pfcrt-CVIET haplotype was present alone in 93.6% (219/234) of the samples over the study period; the wild-type chloroquine- and amodiaquine-sensitive haplotype pfcrt-CVMNK was present in 4.3% (10/234) of the samples; and both haplotypes were present in 2.1% (5/234) of the samples. No significant change in wild-type pfcrt-CVMNK prevalence was evident over the 4-year period of the study. The pfcrt-SVMNT haplotype associated with high-level amodiaquine resistance was not detected in this study. The pfmdr1 locus was genotyped in 178 of these samples. The pfmdr1-YYNY haplotype predominated in 67.4% (120/178) of infections and was significantly associated with the pfcrt-CVIET haplotype. All samples carried the wild-type pfmdr1-N1042 codon. The ms-4760 repeat on pfnhe1 locus displayed 12 distinct haplotypes with ms-4760-1 predominating in the population. Analysis of these haplotypes showed no association of a particular haplotype with quinine treatment outcome. CONCLUSION The pfcrt-CVIET chloroquine resistance haplotype dominated in the collection of P. falciparum samples from Muheza. The pfcrt-SVMNT haplotype, which threatens the efficacy of amodiaquine and was reported in the same time period from Korogwe, Tanzania, 40 Km from Muheza, was not detected. Relative low prevalence of pfcrt-SVMNT in Africa may result from genetic or other factors rendering P. falciparum less supportive of this haplotype than in South America or other regions. TRIAL REGISTRATION Trial Protocol Number: 08-I-N064.
Collapse
Affiliation(s)
- Nahla B Gadalla
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA.
| | - Gloria Tavera
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA.
- Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
| | - Jianbing Mu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA.
| | - Edward R Kabyemela
- Muhimbili University of Health and Allied Sciences, Dar es Salaam, Tanzania.
| | - Michael Fried
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA.
| | - Patrick E Duffy
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA.
| | - Juliana M Sá
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA.
| | - Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD, USA.
| |
Collapse
|
8
|
Mosha D, Mazuguni F, Mrema S, Sevene E, Abdulla S, Genton B. Safety of artemether-lumefantrine exposure in first trimester of pregnancy: an observational cohort. Malar J 2014; 13:197. [PMID: 24884890 PMCID: PMC4040412 DOI: 10.1186/1475-2875-13-197] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 05/22/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There is limited data available regarding safety profile of artemisinins in early pregnancy. They are, therefore, not recommended by WHO as a first-line treatment for malaria in first trimester due to associated embryo-foetal toxicity in animal studies. The study assessed birth outcome among pregnant women inadvertently exposed to artemether-lumefantrine (AL) during first trimester in comparison to those of women exposed to other anti-malarial drugs or no drug at all during the same period of pregnancy. METHODS Pregnant women with gestational age <20 weeks were recruited from Maternal Health clinics or from monthly house visits (demographic surveillance), and followed prospectively until delivery. RESULTS 2167 pregnant women were recruited and 1783 (82.3%) completed the study until delivery. 319 (17.9%) used anti-malarials in first trimester, of whom 172 (53.9%) used (AL), 78 (24.4%) quinine, 66 (20.7%) sulphadoxine-pyrimethamine (SP) and 11 (3.4%) amodiaquine. Quinine exposure in first trimester was associated with an increased risk of miscarriage/stillbirth (OR 2.5; 1.3-5.1) and premature birth (OR 2.6; 1.3-5.3) as opposed to AL with (OR 1.4; 0.8-2.5) for miscarriage/stillbirth and (OR 0.9; 0.5-1.8) for preterm birth. Congenital anomalies were identified in 4 exposure groups namely AL only (1/164[0.6%]), quinine only (1/70[1.4%]), SP (2/66[3.0%]), and non-anti-malarial exposure group (19/1464[1.3%]). CONCLUSION Exposure to AL in first trimester was more common than to any other anti-malarial drugs. Quinine exposure was associated with adverse pregnancy outcomes which was not the case following other anti-malarial intake. Since AL and quinine were used according to their availability rather than to disease severity, it is likely that the effect observed was related to the drug and not to the disease itself. Even with this caveat, a change of policy from quinine to AL for the treatment of uncomplicated malaria during the whole pregnancy period could be already envisaged.
Collapse
Affiliation(s)
- Dominic Mosha
- Ifakara Health Institute, Rufiji HDSS, P,O Box 40, Rufiji, Tanzania.
| | | | | | | | | | | |
Collapse
|
9
|
Sanchez CP, Liu CH, Mayer S, Nurhasanah A, Cyrklaff M, Mu J, Ferdig MT, Stein WD, Lanzer M. A HECT ubiquitin-protein ligase as a novel candidate gene for altered quinine and quinidine responses in Plasmodium falciparum. PLoS Genet 2014; 10:e1004382. [PMID: 24830312 PMCID: PMC4022464 DOI: 10.1371/journal.pgen.1004382] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 04/01/2014] [Indexed: 11/18/2022] Open
Abstract
The emerging resistance to quinine jeopardizes the efficacy of a drug that has been used in the treatment of malaria for several centuries. To identify factors contributing to differential quinine responses in the human malaria parasite Plasmodium falciparum, we have conducted comparative quantitative trait locus analyses on the susceptibility to quinine and also its stereoisomer quinidine, and on the initial and steady-state intracellular drug accumulation levels in the F1 progeny of a genetic cross. These data, together with genetic screens of field isolates and laboratory strains associated differential quinine and quinidine responses with mutated pfcrt, a segment on chromosome 13, and a novel candidate gene, termed MAL7P1.19 (encoding a HECT ubiquitin ligase). Despite a strong likelihood of association, episomal transfections demonstrated a role for the HECT ubiquitin-protein ligase in quinine and quinidine sensitivity in only a subset of genetic backgrounds, and here the changes in IC50 values were moderate (approximately 2-fold). These data show that quinine responsiveness is a complex genetic trait with multiple alleles playing a role and that more experiments are needed to unravel the role of the contributing factors. Quinine, a natural product from cinchona bark, has been used in the treatment of malaria for centuries. Unfortunately, a progressive loss in responsiveness of the human malaria parasite Plasmodium falciparum to quinine has been observed, particularly in Southeast Asia, where cases of quinine treatment failure regularly occur. To better understand how P. falciparum defends itself against the cytotoxic activity of quinine, we have conducted comparative linkage analyses in the F1 progeny of a genetic cross where we assessed the susceptibility and the amount of intracellular accumulation of quinine and of its stereoisomer quinidine. These data identified a novel candidate gene encoding a HECT ubiquitin-protein ligase that might contribute to altered quinine responsiveness. The identification of this novel gene might improve the surveillance of quinine-resistant malaria parasites in the field and aid the preservation of this valuable antimalarial drug.
Collapse
Affiliation(s)
- Cecilia P. Sanchez
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Chia-Hao Liu
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Sybille Mayer
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Astutiati Nurhasanah
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
- Laboratory for the Development of Agroindustrial and Biomedical Technology (LAPTIAB), Tangerang Selatan, Indonesia
| | - Marek Cyrklaff
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | - Jianbing Mu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, United States of America
| | - Michael T. Ferdig
- The Eck Institute for Global Health, Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Wilfred D. Stein
- Biological Chemistry, Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Givat Ram, Jerusalem, Israel
| | - Michael Lanzer
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
- * E-mail:
| |
Collapse
|
10
|
Abstract
As it grows and replicates within the erythrocytes of its host the malaria parasite takes up nutrients from the extracellular medium, exports metabolites and maintains a tight control over its internal ionic composition. These functions are achieved via membrane transport proteins, integral membrane proteins that mediate the passage of solutes across the various membranes that separate the biochemical machinery of the parasite from the extracellular environment. Proteins of this type play a key role in antimalarial drug resistance, as well as being candidate drug targets in their own right. This review provides an overview of recent work on the membrane transport biology of the malaria parasite-infected erythrocyte, encompassing both the parasite-induced changes in the membrane transport properties of the host erythrocyte and the cell physiology of the intracellular parasite itself.
Collapse
|
11
|
Plasmodium falciparum Polymorphisms associated with ex vivo drug susceptibility and clinical effectiveness of artemisinin-based combination therapies in Benin. Antimicrob Agents Chemother 2013; 58:1-10. [PMID: 24100489 DOI: 10.1128/aac.01790-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Artemisinin-based combination therapies (ACTs) are the main option to treat malaria, and their efficacy and susceptibility must be closely monitored to avoid resistance. We assessed the association of Plasmodium falciparum polymorphisms and ex vivo drug susceptibility with clinical effectiveness. Patients enrolled in an effectiveness trial comparing artemether-lumefantrine (n = 96), fixed-dose artesunate-amodiaquine (n = 96), and sulfadoxine-pyrimethamine (n = 48) for the treatment of uncomplicated malaria 2007 in Benin were assessed. pfcrt, pfmdr1, pfmrp1, pfdhfr, and pfdhps polymorphisms were analyzed pretreatment and in recurrent infections. Drug susceptibility was determined in fresh baseline isolates by Plasmodium lactate dehydrogenase enzyme-linked immunosorbent assay (ELISA). A majority had 50% inhibitory concentration (IC50) estimates (the concentration required for 50% growth inhibition) lower than those of the 3D7 reference clone for desethylamodiaquine, lumefantrine, mefloquine, and quinine and was considered to be susceptible, while dihydroartemisinin and pyrimethamine IC50s were higher. No association was found between susceptibility to the ACT compounds and treatment outcome. Selection was observed for the pfmdr1 N86 allele in artemether-lumefantrine recrudescences (recurring infections) (4/7 [57.1%] versus 36/195 [18.5%]), and of the opposite allele, 86Y, in artesunate-amodiaquine reinfections (new infections) (20/22 [90.9%] versus 137/195 [70.3%]) compared to baseline infections. The importance of pfmdr1 N86 in lumefantrine tolerance was emphasized by its association with elevated lumefantrine IC50s. Genetic linkage between N86 and Y184 was observed, which together with the low frequency of 1246Y may explain regional differences in selection of pfmdr1 loci. Selection of opposite alleles in artemether-lumefantrine and artesunate-amodiaquine recurrent infections supports the strategy of multiple first-line treatment. Surveillance based on clinical, ex vivo, molecular, and pharmacological data is warranted.
Collapse
|
12
|
Andriantsoanirina V, Khim N, Ratsimbasoa A, Witkowski B, Benedet C, Canier L, Bouchier C, Tichit M, Durand R, Ménard D. Plasmodium falciparum Na+/H+ exchanger (pfnhe-1) genetic polymorphism in Indian Ocean malaria-endemic areas. Am J Trop Med Hyg 2012. [PMID: 23208889 DOI: 10.4269/ajtmh.2012.12-0359] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
To date, 11 studies conducted in different countries to test the association between Plasmodium falciparum Na(+)/H(+) exchanger gene (pfnhe-1; PF13_0019) polymorphisms and in vitro susceptibility to quinine have generated conflicting data. In this context and to extend our knowledge of the genetic polymorphism of Pfnhe gene, we have sequenced the ms4760 locus from 595 isolates collected in the Comoros (N = 250; an area with a high prevalence of chloroquine and sulfadoxine-pyrimethamine resistance) and Madagascar (N = 345; a low drug-resistance area). Among them, 29 different alleles were observed, including 8 (27%) alleles not previously described. Isolates from the Comoros showed more repeats in block II (DNNND), which some studies have found to be positively associated with in vitro resistance to quinine, compared with isolates from Madagascar. Additional studies are required to better define the mechanisms underlying quinine resistance, which involve multiple gene interactions.
Collapse
|
13
|
Ménard D, Andriantsoanirina V, Khim N, Ratsimbasoa A, Witkowski B, Benedet C, Canier L, Mercereau-Puijalon O, Durand R. Global analysis of Plasmodium falciparum Na(+)/H(+) exchanger (pfnhe-1) allele polymorphism and its usefulness as a marker of in vitro resistance to quinine. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2012; 3:8-19. [PMID: 24533289 DOI: 10.1016/j.ijpddr.2012.10.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Revised: 10/06/2012] [Accepted: 10/09/2012] [Indexed: 11/30/2022]
Abstract
The aim of this study was to provide a comprehensive analysis of the worldwide genetic polymorphism of ms4760 alleles of the pfnhe-1 gene and to discuss their usefulness as molecular marker of quinine resistance (QNR). A new numbering of ms4760 allele, classification grouping ms4760 alleles according to the number of DNNND and DDNHNDNHNND repeat motifs in blocks II and V was also proposed. A total of 1508 ms4760 sequences from isolates, culture-adapted parasites or reference strains from various geographical regions were retrieved from GenBank (last update on 15th June 2012) or from publications and were used for genetic analyses. The association of different alleles of pfnhe-1 with resistance to quinoline antimalarial drugs showed marked geographic disparities. The validity and reliability of candidate polymorphisms in pfnhe-1 gene as molecular markers of QNR appeared restricted to endemic areas from South Asia or possibly East African countries and needs to be confirmed.
Collapse
Affiliation(s)
- Didier Ménard
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | | | - Nimol Khim
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Arsène Ratsimbasoa
- Ministère de la Santé, du Planning Familial et de la Protection Sociale, Programme National de Lutte contre le Paludisme, BP 1869 Antananarivo, Madagascar
| | - Benoit Witkowski
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Christophe Benedet
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Lydie Canier
- Unité d'Epidémiologie Moléculaire du Paludisme, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
| | - Odile Mercereau-Puijalon
- Unité d'Immunologie Moléculaire des Parasites, Institut Pasteur & Centre National de la Recherche Scientifique, Unité de Recherche Associée 2581, Paris, France
| | - Rémy Durand
- Laboratoire de Parasitologie-Mycologie, Hôpital Avicenne, AP-HP, Bobigny, France
| |
Collapse
|
14
|
Bohórquez EB, Chua M, Meshnick SR. Quinine localizes to a non-acidic compartment within the food vacuole of the malaria parasite Plasmodium falciparum. Malar J 2012; 11:350. [PMID: 23088166 PMCID: PMC3520729 DOI: 10.1186/1475-2875-11-350] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 10/18/2012] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The naturally fluorescent compound quinine has long been used to treat malaria infections. Although some evidence suggests that quinine acts in the parasite food vacuole, the mechanism of action of quinine has not yet been resolved. The Plasmodium falciparum multidrug resistance (pfmdr1) gene encodes a food vacuolar membrane transporter and has been linked with parasite resistance to quinine. The effect of multiple pfmdr1 copies on the subcellular localization of quinine was explored. METHODS Fluorescence microscopy was used to evaluate the subcellular localization of quinine in parasites containing different pfmdr1 copy numbers to determine if copy number of the gene affects drug localization. The acidotropic dye LysoTracker Red was used to label the parasite food vacuole. Time-lapse images were taken to determine quinine localization over time following quinine exposure. RESULTS Regardless of pfmdr1 copy number, quinine overlapped with haemozoin but did not colocalize with LysoTracker Red, which labeled the acidic parasite food vacuole. CONCLUSIONS Quinine localizes to a non-acidic compartment within the food vacuole possibly haemozoin. Pfmdr1 copy number does not affect quinine subcellular localization.
Collapse
Affiliation(s)
- Elaine B Bohórquez
- Department of Epidemiology, University of North Carolina at Chapel Hill, Campus Box 7435, Chapel Hill, NC 27599-7435, USA
| | | | | |
Collapse
|
15
|
Chan CW, Spathis R, Reiff DM, McGrath SE, Garruto RM, Lum JK. Diversity of Plasmodium falciparum chloroquine resistance transporter (pfcrt) exon 2 haplotypes in the Pacific from 1959 to 1979. PLoS One 2012; 7:e30213. [PMID: 22272308 PMCID: PMC3260253 DOI: 10.1371/journal.pone.0030213] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 12/13/2011] [Indexed: 12/03/2022] Open
Abstract
Nearly one million deaths are attributed to malaria every year. Recent reports of multi-drug treatment failure of falciparum malaria underscore the need to understand the molecular basis of drug resistance. Multiple mutations in the Plasmodium falciparum chloroquine resistance transporter (pfcrt) are involved in chloroquine resistance, but the evolution of complex haplotypes is not yet well understood. Using over 4,500 archival human serum specimens collected from 19 Pacific populations between 1959 and 1979, the period including and just prior to the appearance of chloroquine treatment failure in the Pacific, we PCR-amplified and sequenced a portion of the pfcrt exon 2 from 771 P. falciparum-infected individuals to explore the spatial and temporal variation in falciparum malaria prevalence and the evolution of chloroquine resistance. In the Pacific, the prevalence of P. falciparum varied considerably across ecological zones. On the island of New Guinea, the decreases in prevalence of P. falciparum in coastal, high-transmission areas over time were contrasted by the increase in prevalence during the same period in the highlands, where transmission was intermittent. We found 78 unique pfcrt haplotypes consisting of 34 amino acid substitutions and 28 synonymous mutations. More importantly, two pfcrt mutations (N75D and K76T) implicated in chloroquine resistance were present in parasites from New Hebrides (now Vanuatu) eight years before the first report of treatment failure. Our results also revealed unexpectedly high levels of genetic diversity in pfcrt exon 2 prior to the historical chloroquine resistance selective sweep, particularly in areas where disease burden was relatively low. In the Pacific, parasite genetic isolation, as well as host acquired immune status and genetic resistance to malaria, were important contributors to the evolution of chloroquine resistance in P. falciparum.
Collapse
Affiliation(s)
- Chim W Chan
- Laboratory of Evolutionary Anthropology and Health, Binghamton University, Binghamton, New York, United States of America.
| | | | | | | | | | | |
Collapse
|
16
|
Abstract
The emergence and spread of drug resistance in the malaria parasite Plasmodium falciparum as well as multi- and extremely drug-resistant forms of Mycobacterium tuberculosis, the causative agent of TB, could hamper the control of these diseases. For instance, there are indications that the malaria parasite is becoming resistant to artemisinin derivatives, drugs that form the backbone of antimalarial combination therapy. Likewise, Mycobacterium tuberculosis strains that are multidrug-resistant or extremely drug-resistant to first- and second-line drugs have been associated with increased mortality. Thus, more than ever, new antimalarials and anti-TB drugs are needed. One of the strategies to discover new drugs is to reposition or repurpose existing drugs, thus reducing the cost and time of drug development. In this review, we discuss how this concept has been used in the past to discover antimalarial and anti-TB drugs, and summarize strategies that can lead to the discovery and development of new drugs.
Collapse
|
17
|
Baseline in vitro activities of the antimalarials pyronaridine and methylene blue against Plasmodium falciparum isolates from Kenya. Antimicrob Agents Chemother 2011; 56:1105-7. [PMID: 22123687 DOI: 10.1128/aac.05454-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
We have analyzed the in vitro activities of pyronaridine and methylene blue against 59 Plasmodium falciparum isolates from Kenya in association with polymorphisms in Pfcrt (codon 76), Pfmdr1 (codon 86), and Pfnhe (full sequence). The median inhibitory concentrations that kill 50% of parasites were 13.5 and 3.3 nM for pyronaridine and methylene blue, respectively. Their activities were not associated with polymorphisms in these genes. The drugs' high in vitro activities indicate that they would be efficacious against Kenyan isolates in vivo.
Collapse
|
18
|
Sanchez CP, Mayer S, Nurhasanah A, Stein WD, Lanzer M. Genetic linkage analyses redefine the roles of PfCRT and PfMDR1 in drug accumulation and susceptibility in Plasmodium falciparum. Mol Microbiol 2011; 82:865-78. [PMID: 21999470 DOI: 10.1111/j.1365-2958.2011.07855.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Resistance to quinoline antimalarial drugs has emerged in different parts of the world and involves sets of discrete mutational changes in pfcrt and pfmdr1 in the human malaria parasite Plasmodium falciparum. To better understand how the different polymorphic haplotypes of pfmdr1 and pfcrt contribute to drug resistance, we have conducted a linkage analysis in the F1 progeny of a genetic cross where we assess both the susceptibility and the amount of accumulation of chloroquine, amodiaquine, quinine and quinidine. Our data show that the different pfcrt and pfmdr1 haplotypes confer drug-specific responses which, depending on the drug, may affect drug accumulation or susceptibility or both. These findings suggest that PfCRT and PfMDR1 are carriers of antimalarial drugs, but that the interaction with a drug interferes with the carriers' natural transport function such that they are now themselves targets of these drugs. How well a mutant PfCRT and PfMDR1 type copes with its competing transport functions is determined by its specific sets of amino acid substitutions.
Collapse
Affiliation(s)
- Cecilia P Sanchez
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany
| | | | | | | | | |
Collapse
|
19
|
Sinou V, Quang LH, Pelleau S, Huong VN, Huong NT, Tai LM, Bertaux L, Desbordes M, Latour C, Long LQ, Thanh NX, Parzy D. Polymorphism of Plasmodium falciparum Na(+)/H(+) exchanger is indicative of a low in vitro quinine susceptibility in isolates from Viet Nam. Malar J 2011; 10:164. [PMID: 21669011 PMCID: PMC3123604 DOI: 10.1186/1475-2875-10-164] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 06/14/2011] [Indexed: 02/05/2023] Open
Abstract
Background The Plasmodium falciparum NA+/H+ exchanger (pfnhe1, gene PF13_0019) has recently been proposed to influence quinine (QN) susceptibility. However, its contribution to QN resistance seems to vary geographically depending on the genetic background of the parasites. Here, the role of this gene was investigated in in vitro QN susceptibility of isolates from Viet Nam. Method Ninety-eight isolates were obtained from three different regions of the Binh Phuoc and Dak Nong bordering Cambodia provinces during 2006-2008. Among these, 79 were identified as monoclonal infection and were genotyped at the microsatellite pfnhe1 ms4760 locus and in vitro QN sensitivity data were obtained for 51 isolates. Parasite growth was assessed in the field using the HRP2 immunodetection assay. Results Significant associations were found between polymorphisms at pfnhe1 microsatellite ms4760 and susceptibility to QN. Isolates with two or more DNNND exhibited much lower susceptibility to QN than those harbouring zero or one DNNND repeats (median IC50 of 682 nM versus median IC50 of 300 nM; p = 0.0146) while isolates with one NHNDNHNNDDD repeat presented significantly reduced QN susceptibility than those who had two (median IC50 of 704 nM versus median IC50 of 375 nM; p < 0.01). These QNR associated genotype features were mainly due to the over representation of profile 7 among isolates (76.5%). The majority of parasites had pfcrt76T and wild-type pfmdr1 (> 95%) thus preventing analysis of associations with these mutations. Interestingly, area with the highest median QN IC50 showed also the highest percentage of isolates carrying the pfnhe1 haplotype 7. Conclusions The haplotype 7 which is the typical Asian profile is likely well-adapted to high drug pressure in this area and may constitute a good genetic marker to evaluate the dissemination of QNR in this part of the world.
Collapse
Affiliation(s)
- Véronique Sinou
- UMR-MD3 Relations Hôte-Parasite, Pharmacologie et Thérapeutique, Université de la Méditerranée, Institut de Médecine Tropicale du Service de Santé des Armées, Antenne IRBA-Marseille, Marseille, France.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Chilengi R, Juma R, Abdallah AM, Bashraheil M, Lodenyo H, Nyakundi P, Anabwani E, Salim A, Mwambingu G, Wenwa E, Jemutai J, Kipkeu C, Oyoo GO, Muchohi SN, Kokwaro G, Niehues T, Lang T, Nzila A. A phase I trial to evaluate the safety and pharmacokinetics of low-dose methotrexate as an anti-malarial drug in Kenyan adult healthy volunteers. Malar J 2011; 10:63. [PMID: 21410944 PMCID: PMC3072355 DOI: 10.1186/1475-2875-10-63] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 03/16/2011] [Indexed: 11/11/2022] Open
Abstract
Background Previous investigations indicate that methotrexate, an old anticancer drug, could be used at low doses to treat malaria. A phase I evaluation was conducted to assess the safety and pharmacokinetic profile of this drug in healthy adult male Kenyan volunteers. Methods Twenty five healthy adult volunteers were recruited and admitted to receive a 5 mg dose of methotrexate/day/5 days. Pharmacokinetics blood sampling was carried out at 2, 4, 6, 12 and 24 hours following each dose. Nausea, vomiting, oral ulcers and other adverse events were solicited during follow up of 42 days. Results The mean age of participants was 23.9 ± 3.3 years. Adherence to protocol was 100%. No grade 3 solicited adverse events were observed. However, one case of transiently elevated liver enzymes, and one serious adverse event (not related to the product) were reported. The maximum concentration (Cmax) was 160-200 nM and after 6 hours, the effective concentration (Ceff) was <150 nM. Conclusion Low-dose methotraxate had an acceptable safety profile. However, methotrexate blood levels did not reach the desirable Ceff of 250-400-nM required to clear malaria infection in vivo. Further dose finding and safety studies are necessary to confirm suitability of this drug as an anti-malarial agent.
Collapse
Affiliation(s)
- Roma Chilengi
- Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme, PO Box 230, 80108 Kilifi, Kenya
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|