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Keita Alassane S, Nicolau-Travers ML, Menard S, Andreoletti O, Cambus JP, Gaudre N, Wlodarczyk M, Blanchard N, Berry A, Abbes S, Colongo D, Faye B, Augereau JM, Lacroux C, Iriart X, Benoit-Vical F. Young Sprague Dawley rats infected by Plasmodium berghei: A relevant experimental model to study cerebral malaria. PLoS One 2017; 12:e0181300. [PMID: 28742109 PMCID: PMC5524346 DOI: 10.1371/journal.pone.0181300] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 06/14/2017] [Indexed: 02/06/2023] Open
Abstract
Cerebral malaria (CM) is the most severe manifestation of human malaria yet is still poorly understood. Mouse models have been developed to address the subject. However, their relevance to mimic human pathogenesis is largely debated. Here we study an alternative cerebral malaria model with an experimental Plasmodium berghei Keyberg 173 (K173) infection in Sprague Dawley rats. As in Human, not all infected subjects showed cerebral malaria, with 45% of the rats exhibiting Experimental Cerebral Malaria (ECM) symptoms while the majority (55%) of the remaining rats developed severe anemia and hyperparasitemia (NoECM). These results allow, within the same population, a comparison of the noxious effects of the infection between ECM and severe malaria without ECM. Among the ECM rats, 77.8% died between day 5 and day 12 post-infection, while the remaining rats were spontaneously cured of neurological signs within 24-48 hours. The clinical ECM signs observed were paresis quickly evolving to limb paralysis, global paralysis associated with respiratory distress, and coma. The red blood cell (RBC) count remained normal but a drastic decrease of platelet count and an increase of white blood cell numbers were noted. ECM rats also showed a decrease of glucose and total CO2 levels and an increase of creatinine levels compared to control rats or rats with no ECM. Assessment of the blood-brain barrier revealed loss of integrity, and interestingly histopathological analysis highlighted cyto-adherence and sequestration of infected RBCs in brain vessels from ECM rats only. Overall, this ECM rat model showed numerous clinical and histopathological features similar to Human CM and appears to be a promising model to achieve further understanding the CM pathophysiology in Humans and to evaluate the activity of specific antimalarial drugs in avoiding/limiting cerebral damages from malaria.
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Affiliation(s)
- Sokhna Keita Alassane
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, Toulouse, France
- Université de Toulouse, UPS, INPT, Toulouse, France
- UFR Sciences de la Santé, Université Gaston Berger, St Louis, Sénégal
| | - Marie-Laure Nicolau-Travers
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, Toulouse, France
- Université de Toulouse, UPS, INPT, Toulouse, France
| | - Sandie Menard
- CPTP (Centre de Physiopathologie de Toulouse Purpan), INSERM U1043, CNRS UMR5282, Université de Toulouse III, Toulouse, France
| | - Olivier Andreoletti
- UMR INRA ENVT 1225, Interactions Hôte Agent Pathogène, Ecole Nationale Vétérinaire de Toulouse, 23 Chemin des Capelles, Toulouse, France
| | - Jean-Pierre Cambus
- Laboratoire Hématologie, Centre Hospitalier Universitaire, Toulouse, France
| | - Noémie Gaudre
- CPTP (Centre de Physiopathologie de Toulouse Purpan), INSERM U1043, CNRS UMR5282, Université de Toulouse III, Toulouse, France
| | - Myriam Wlodarczyk
- CPTP (Centre de Physiopathologie de Toulouse Purpan), INSERM U1043, CNRS UMR5282, Université de Toulouse III, Toulouse, France
| | - Nicolas Blanchard
- CPTP (Centre de Physiopathologie de Toulouse Purpan), INSERM U1043, CNRS UMR5282, Université de Toulouse III, Toulouse, France
| | - Antoine Berry
- Service de Parasitologie-Mycologie, Centre Hospitalier Universitaire, Toulouse, France
| | - Sarah Abbes
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, Toulouse, France
- Université de Toulouse, UPS, INPT, Toulouse, France
| | | | - Babacar Faye
- UFR Sciences de la Santé, Université Gaston Berger, St Louis, Sénégal
| | - Jean-Michel Augereau
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, Toulouse, France
- Université de Toulouse, UPS, INPT, Toulouse, France
| | - Caroline Lacroux
- UMR INRA ENVT 1225, Interactions Hôte Agent Pathogène, Ecole Nationale Vétérinaire de Toulouse, 23 Chemin des Capelles, Toulouse, France
| | - Xavier Iriart
- CPTP (Centre de Physiopathologie de Toulouse Purpan), INSERM U1043, CNRS UMR5282, Université de Toulouse III, Toulouse, France
- Service de Parasitologie-Mycologie, Centre Hospitalier Universitaire, Toulouse, France
| | - Françoise Benoit-Vical
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, Toulouse, France
- Université de Toulouse, UPS, INPT, Toulouse, France
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52
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Biochemistry of malaria parasite infected red blood cells by X-ray microscopy. Sci Rep 2017; 7:802. [PMID: 28400621 PMCID: PMC5429762 DOI: 10.1038/s41598-017-00921-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 03/16/2017] [Indexed: 01/17/2023] Open
Abstract
Red blood cells infected by the malaria parasite Plasmodium falciparum are correlatively imaged by tomography using soft X-rays as well as by scanning hard nano-X-ray beam to obtain fluorescence maps of various elements such as S and Fe. In this way one can deduce the amount of Fe bound either in hemoglobin or in hemozoin crystals in the digestive vacuole of the malaria parasite as well as determine the hemoglobin concentrations in the cytosols of the red blood cell and of the parasite. Fluorescence map of K shows that in the parasite’s schizont stage the K concentration in the red blood cell cytosol is diminished by a factor of seven relative to a pristine red blood cell but the total amount of K in the infected red blood cell is the same as in the pristine red blood cell.
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53
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Videvall E, Cornwallis CK, Ahrén D, Palinauskas V, Valkiūnas G, Hellgren O. The transcriptome of the avian malaria parasite Plasmodium ashfordi
displays host-specific gene expression. Mol Ecol 2017; 26:2939-2958. [DOI: 10.1111/mec.14085] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 01/16/2017] [Accepted: 02/17/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Elin Videvall
- Department of Biology; Lund University; Sölvegatan 37 SE-22362 Lund Sweden
| | | | - Dag Ahrén
- Department of Biology; Lund University; Sölvegatan 37 SE-22362 Lund Sweden
- National Bioinformatics Infrastructure Sweden (NBIS); Lund University; Sölvegatan 37 SE-22362 Lund Sweden
| | - Vaidas Palinauskas
- Institute of Ecology; Nature Research Centre; Akademijos 2 LT-08412 Vilnius Lithuania
| | - Gediminas Valkiūnas
- Institute of Ecology; Nature Research Centre; Akademijos 2 LT-08412 Vilnius Lithuania
| | - Olof Hellgren
- Department of Biology; Lund University; Sölvegatan 37 SE-22362 Lund Sweden
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54
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Strangward P, Haley MJ, Shaw TN, Schwartz JM, Greig R, Mironov A, de Souza JB, Cruickshank SM, Craig AG, Milner DA, Allan SM, Couper KN. A quantitative brain map of experimental cerebral malaria pathology. PLoS Pathog 2017; 13:e1006267. [PMID: 28273147 PMCID: PMC5358898 DOI: 10.1371/journal.ppat.1006267] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/20/2017] [Accepted: 03/01/2017] [Indexed: 11/19/2022] Open
Abstract
The murine model of experimental cerebral malaria (ECM) has been utilised extensively in recent years to study the pathogenesis of human cerebral malaria (HCM). However, it has been proposed that the aetiologies of ECM and HCM are distinct, and, consequently, no useful mechanistic insights into the pathogenesis of HCM can be obtained from studying the ECM model. Therefore, in order to determine the similarities and differences in the pathology of ECM and HCM, we have performed the first spatial and quantitative histopathological assessment of the ECM syndrome. We demonstrate that the accumulation of parasitised red blood cells (pRBCs) in brain capillaries is a specific feature of ECM that is not observed during mild murine malaria infections. Critically, we show that individual pRBCs appear to occlude murine brain capillaries during ECM. As pRBC-mediated congestion of brain microvessels is a hallmark of HCM, this suggests that the impact of parasite accumulation on cerebral blood flow may ultimately be similar in mice and humans during ECM and HCM, respectively. Additionally, we demonstrate that cerebrovascular CD8+ T-cells appear to co-localise with accumulated pRBCs, an event that corresponds with development of widespread vascular leakage. As in HCM, we show that vascular leakage is not dependent on extensive vascular destruction. Instead, we show that vascular leakage is associated with alterations in transcellular and paracellular transport mechanisms. Finally, as in HCM, we observed axonal injury and demyelination in ECM adjacent to diverse vasculopathies. Collectively, our data therefore shows that, despite very different presentation, and apparently distinct mechanisms, of parasite accumulation, there appear to be a number of comparable features of cerebral pathology in mice and in humans during ECM and HCM, respectively. Thus, when used appropriately, the ECM model may be useful for studying specific pathological features of HCM.
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Affiliation(s)
- Patrick Strangward
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Michael J. Haley
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Tovah N. Shaw
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Jean-Marc Schwartz
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Rachel Greig
- Immunology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Aleksandr Mironov
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - J. Brian de Souza
- Immunology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sheena M. Cruickshank
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Alister G. Craig
- Department of Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Danny A. Milner
- Department of Pathology, The Brigham & Women’s Hospital, Boston, Massachusetts, United States of America
| | - Stuart M. Allan
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Kevin N. Couper
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
- * E-mail:
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55
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Ssentongo P, Robuccio AE, Thuku G, Sim DG, Nabi A, Bahari F, Shanmugasundaram B, Billard MW, Geronimo A, Short KW, Drew PJ, Baccon J, Weinstein SL, Gilliam FG, Stoute JA, Chinchilli VM, Read AF, Gluckman BJ, Schiff SJ. A Murine Model to Study Epilepsy and SUDEP Induced by Malaria Infection. Sci Rep 2017; 7:43652. [PMID: 28272506 PMCID: PMC5341121 DOI: 10.1038/srep43652] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/25/2017] [Indexed: 12/28/2022] Open
Abstract
One of the largest single sources of epilepsy in the world is produced as a neurological sequela in survivors of cerebral malaria. Nevertheless, the pathophysiological mechanisms of such epileptogenesis remain unknown and no adjunctive therapy during cerebral malaria has been shown to reduce the rate of subsequent epilepsy. There is no existing animal model of postmalarial epilepsy. In this technical report we demonstrate the first such animal models. These models were created from multiple mouse and parasite strain combinations, so that the epilepsy observed retained universality with respect to genetic background. We also discovered spontaneous sudden unexpected death in epilepsy (SUDEP) in two of our strain combinations. These models offer a platform to enable new preclinical research into mechanisms and prevention of epilepsy and SUDEP.
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Affiliation(s)
- Paddy Ssentongo
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Anna E. Robuccio
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Godfrey Thuku
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
| | - Derek G. Sim
- Center for Infectious Disease Dynamics, Penn State University, University Park, Pennsylvania 16802, USA
- Departments of Biology and Entomology, Penn State University, University Park, Pennsylvania 16802, USA
| | - Ali Nabi
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
| | - Fatemeh Bahari
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
| | - Balaji Shanmugasundaram
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
| | - Myles W. Billard
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
| | - Andrew Geronimo
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Neurosurgery, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Kurt W. Short
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Neurosurgery, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Patrick J. Drew
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Neurosurgery, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
- Department of Bioengineering, Penn State University, University Park, Hershey, Pennsylvania, 16803, USA
| | - Jennifer Baccon
- Department of Neurosurgery, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
- Department of Pathology, Penn State College of Medicine, Hershey, Hershey, Pennsylvania 17033, USA
| | - Steven L. Weinstein
- Department of Neurology, Children’s National Medical Center, George Washington University, Washington, DC 20010, USA
| | - Frank G. Gilliam
- Department of Neurosurgery, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
- Department of Neurology, Penn State College of Medicine, Hershey, Hershey, Pennsylvania 17033, USA
| | - José A. Stoute
- Department of Medicine, Penn State University College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Vernon M. Chinchilli
- Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
| | - Andrew F. Read
- Center for Infectious Disease Dynamics, Penn State University, University Park, Pennsylvania 16802, USA
- Departments of Biology and Entomology, Penn State University, University Park, Pennsylvania 16802, USA
| | - Bruce J. Gluckman
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Neurosurgery, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
- Department of Bioengineering, Penn State University, University Park, Hershey, Pennsylvania, 16803, USA
| | - Steven J. Schiff
- Center for Neural Engineering, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Engineering Science and Mechanics, Penn State University, University Park, Pennsylvania 16802, USA
- Center for Infectious Disease Dynamics, Penn State University, University Park, Pennsylvania 16802, USA
- Department of Neurosurgery, Penn State College of Medicine, Hershey, Pennsylvania 17033, USA
- Department of Physics, Penn State University, University Park, Pennsylvania, 16803, USA
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56
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Saiwaew S, Sritabal J, Piaraksa N, Keayarsa S, Ruengweerayut R, Utaisin C, Sila P, Niramis R, Udomsangpetch R, Charunwatthana P, Pongponratn E, Pukrittayakamee S, Leitgeb AM, Wahlgren M, Lee SJ, Day NPJ, White NJ, Dondorp AM, Chotivanich K. Effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum infected erythrocytes. PLoS One 2017; 12:e0172718. [PMID: 28249043 PMCID: PMC5332063 DOI: 10.1371/journal.pone.0172718] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 02/08/2017] [Indexed: 12/04/2022] Open
Abstract
In severe falciparum malaria cytoadherence of parasitised red blood cells (PRBCs) to vascular endothelium (causing sequestration) and to uninfected red cells (causing rosette formation) contribute to microcirculatory flow obstruction in vital organs. Heparin can reverse the underlying ligand-receptor interactions, but may increase the bleeding risks. As a heparin-derived polysaccharide, sevuparin has been designed to retain anti-adhesive properties, while the antithrombin-binding domains have been eliminated, substantially diminishing its anticoagulant activity. Sevuparin has been evaluated recently in patients with uncomplicated falciparum malaria, and is currently investigated in a clinical trial for sickle cell disease. The effects of sevuparin on rosette formation and cytoadherence of Plasmodium falciparum isolates from Thailand were investigated. Trophozoite stages of P. falciparum-infected RBCs (Pf-iRBCs) were cultured from 49 patients with malaria. Pf-iRBCs were treated with sevuparin at 37°C and assessed in rosetting and in cytoadhesion assays with human dermal microvascular endothelial cells (HDMECs) under static and flow conditions. The proportion of Pf-iRBCs forming rosettes ranged from 6.5% to 26.0% (median = 12.2%). Rosetting was dose dependently disrupted by sevuparin (50% disruption by 250 μg/mL). Overall 57% of P. falciparum isolates bound to HDMECs under static conditions; median (interquartile range) Pf-iRBC binding was 8.5 (3.0–38.0) Pf-iRBCs/1000 HDMECs. Sevuparin in concentrations ≥ 100 μg/mL inhibited cytoadherence. Sevuparin disrupts P. falciparum rosette formation in a dose dependent manner and inhibits cytoadherence to endothelial cells. The data support assessment of sevuparin as an adjunctive treatment to the standard therapy in severe falciparum malaria.
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Affiliation(s)
- Somporn Saiwaew
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Juntima Sritabal
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Nattaporn Piaraksa
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Srisuda Keayarsa
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Patima Sila
- Mae Ramat Hospital, Mae Ramat, Tak, Thailand
| | - Rangsan Niramis
- Queen Sirikit National Institute of Child Health, Bangkok, Thailand
| | - Rachanee Udomsangpetch
- Center for Research and Innovation, Faculty of Medical Technology, Mahidol University, Nakhon Pathom, Thailand
| | - Prakaykaew Charunwatthana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Emsri Pongponratn
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sasithon Pukrittayakamee
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Sue J. Lee
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas P. J. Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Arjen M. Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Kesinee Chotivanich
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- * E-mail:
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57
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Abstract
Following anti-malarial drug treatment asexual malaria parasite killing and clearance appear to be first order processes. Damaged malaria parasites in circulating erythrocytes are removed from the circulation mainly by the spleen. Splenic clearance functions increase markedly in acute malaria. Either the entire infected erythrocytes are removed because of their reduced deformability or increased antibody binding or, for the artemisinins which act on young ring stage parasites, splenic pitting of drug-damaged parasites is an important mechanism of clearance. The once-infected erythrocytes returned to the circulation have shortened survival. This contributes to post-artesunate haemolysis that may follow recovery in non-immune hyperparasitaemic patients. As the parasites mature Plasmodium vivax-infected erythrocytes become more deformable, whereas Plasmodium falciparum-infected erythrocytes become less deformable, but they escape splenic filtration by sequestering in venules and capillaries. Sequestered parasites are killed in situ by anti-malarial drugs and then disintegrate to be cleared by phagocytic leukocytes. After treatment with artemisinin derivatives some asexual parasites become temporarily dormant within their infected erythrocytes, and these may regrow after anti-malarial drug concentrations decline. Artemisinin resistance in P. falciparum reflects reduced ring stage susceptibility and manifests as slow parasite clearance. This is best assessed from the slope of the log-linear phase of parasitaemia reduction and is commonly measured as a parasite clearance half-life. Pharmacokinetic-pharmacodynamic modelling of anti-malarial drug effects on parasite clearance has proved useful in predicting therapeutic responses and in dose-optimization.
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Affiliation(s)
- Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Bangkok, 10400, Thailand.
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58
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Gillrie MR, Ho M. Dynamic interactions of Plasmodium spp. with vascular endothelium. Tissue Barriers 2017; 5:e1268667. [PMID: 28452684 PMCID: PMC5362994 DOI: 10.1080/21688370.2016.1268667] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 11/24/2016] [Accepted: 11/30/2016] [Indexed: 12/18/2022] Open
Abstract
Plasmodial species are protozoan parasites that infect erythrocytes. As such, they are in close contact with microvascular endothelium for most of the life cycle in the mammalian host. The host-parasite interactions of this stage of the infection are responsible for the clinical manifestations of the disease that range from a mild febrile illness to severe and frequently fatal syndromes such as cerebral malaria and multi-organ failure. Plasmodium falciparum, the causative agent of the most severe form of malaria, is particularly predisposed to modulating endothelial function through either direct adhesion to endothelial receptor molecules, or by releasing potent host and parasite products that can stimulate endothelial activation and/or disrupt barrier function. In this review, we provide a critical analysis of the current clinical and laboratory evidence for endothelial dysfunction during severe P. falciparum malaria. Future investigations using state-of-the-art technologies such as mass cytometry and organs-on-chips to further delineate parasite-endothelial cell interactions are also discussed.
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Affiliation(s)
- Mark R. Gillrie
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - May Ho
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada
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59
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Thrombin Cleavage of Plasmodium falciparum Erythrocyte Membrane Protein 1 Inhibits Cytoadherence. mBio 2016; 7:mBio.01120-16. [PMID: 27624125 PMCID: PMC5021802 DOI: 10.1128/mbio.01120-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum malaria remains one of the most deadly infections worldwide. The pathogenesis of the infection results from the sequestration of infected erythrocytes (IRBC) in vital organs, including the brain, with resulting impairment of blood flow, hypoxia, and lactic acidosis. Sequestration occurs through the adhesion of IRBC to host receptors on microvascular endothelium by Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), a large family of variant surface antigens, each with up to seven extracellular domains that can bind to multiple host receptors. Consequently, antiadhesive therapies directed at single endothelial adhesion molecules may not be effective. In this study, we demonstrated that the serine protease thrombin, which is pivotal in the activation of the coagulation cascade, cleaved the major parasite adhesin on the surface of IRBC. As a result, adhesion under flow was dramatically reduced, and already adherent IRBC were detached. Thrombin cleavage sites were mapped to the Duffy binding-like δ1 (DBLδ1) domain and interdomains 1 and 2 in the PfEMP1 of the parasite line IT4var19. Furthermore, we observed an inverse correlation between the presence of thrombin and IRBC in cerebral malaria autopsies of children. We investigated a modified (R67A) thrombin and thrombin inhibitor, hirugen, both of which inhibit the binding of substrates to exosite I, thereby reducing its proinflammatory properties. Both approaches reduced the barrier dysfunction induced by thrombin without affecting its proteolytic activity on PfEMP1, raising the possibility that thrombin cleavage of variant PfEMP1 may be exploited as a broadly inhibitory antiadhesive therapy. Plasmodium falciparum malaria is the third leading cause of mortality due to a pathogen, with 214 million people infected and 438,000 deaths annually. The adhesion of Plasmodium falciparum-infected erythrocytes (IRBC) to microvascular endothelium is a major pathological process in severe malaria. While the recent implementation of artemisinin-based antimalarial therapy for severe malaria improves patient survival by targeting all parasite stages, antiparasite drugs alone may not immediately reverse pathophysiological processes in occluded vessels. Here we show that thrombin, an enzyme intimately involved in the clotting process, cleaves the main parasite adhesin expressed on the surface of IRBC, thereby preventing and reversing the binding of IRBC to endothelial cells. This beneficial effect of thrombin can be achieved by modified thrombins that cause significantly less clotting and vessel leakage while preserving the ability to cleave the parasite protein. Our results provide the basis for using modified thrombins as adjunctive therapy in severe malaria.
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60
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Wudneh F, Assefa A, Nega D, Mohammed H, Solomon H, Kebede T, Woyessa A, Assefa Y, Kebede A, Kassa M. Open-label trial on efficacy of artemether/lumefantrine against the uncomplicated Plasmodium falciparum malaria in Metema district, Northwestern Ethiopia. Ther Clin Risk Manag 2016; 12:1293-300. [PMID: 27601913 PMCID: PMC5005000 DOI: 10.2147/tcrm.s113603] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Purpose Following the increased Plasmodium falciparum resistance to chloroquine and sulfadoxine/pyrimethamine, Ethiopia adopted artemether/lumefantrine (AL) as the first-line treatment for uncomplicated P. falciparum in 2004. According to the recommendation of the World Health Organization, this study was carried out for regular monitoring of the efficacy of AL in treating the uncomplicated P. falciparum malaria in Metema district, Gondar Zone, Northwest Ethiopia. Patients and methods This is a one-arm prospective 28-day in vivo therapeutic efficacy study among the uncomplicated P. falciparum malaria patients aged 6 months and older. The study was conducted from October 2014 to January 2015, based on the revised World Health Organization protocol of 2009 for surveillance of antimalarial drug therapeutic efficacy study. Standard six-dose regimen of AL was given twice daily for 3 days, and then the treatment outcomes were assessed on days 0, 1, 2, 3, 7, 14, 21, 28, and any other unscheduled day for emergency cases. Results There were 91 study subjects enrolled in this study, of whom 80 study subjects completed the full follow-up schedules and showed adequate clinical and parasitological responses on day 28, with no major adverse event. Per protocol analysis, the unadjusted cure rate of Coartem® was 98.8% (95% confidence interval: 93.3%–100%) in the study area. Recurrence of one P. falciparum case was detected on day 28, with a late parasitological failure rate of 1.2%. No early treatment failure occurred. Complete parasite and fever clearance was observed on day 3. Gametocyte carriage was 4.4% at enrollment that cleared on day 21. Although the difference is statistically not significant, a slight increase in the level of mean hemoglobin from baseline to day 28 was observed. Conclusion The study showed high efficacy and tolerability of Coartem® against uncomplicated P. falciparum malaria, suggesting the continuation as a first-line drug in the study district. However, regular monitoring of the therapeutic efficacy of the drug, possibly with plasma drug-level measurement, is critical among the mobile border population.
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Affiliation(s)
- Feven Wudneh
- Department of Microbiology, Immunology and Parasitology, School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa; Biomedical Department, College of Health Sciences and Medicine, Dilla University, Dilla
| | - Ashenafi Assefa
- Malaria and Other Parasitological and Entomological Research Team, Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute
| | - Desalegn Nega
- Malaria and Other Parasitological and Entomological Research Team, Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute
| | - Hussien Mohammed
- Malaria and Other Parasitological and Entomological Research Team, Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute
| | - Hiwot Solomon
- Malaria Research Team, Disease Prevention and Control Directorate, Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Tadesse Kebede
- Biomedical Department, College of Health Sciences and Medicine, Dilla University, Dilla
| | - Adugna Woyessa
- Malaria and Other Parasitological and Entomological Research Team, Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute
| | - Yibeltal Assefa
- Malaria and Other Parasitological and Entomological Research Team, Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute
| | - Amha Kebede
- Malaria and Other Parasitological and Entomological Research Team, Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute
| | - Moges Kassa
- Malaria and Other Parasitological and Entomological Research Team, Bacterial, Parasitic and Zoonotic Diseases Research Directorate, Ethiopian Public Health Institute
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Quintana MDP, Angeletti D, Moll K, Chen Q, Wahlgren M. Phagocytosis-inducing antibodies to Plasmodium falciparum upon immunization with a recombinant PfEMP1 NTS-DBL1α domain. Malar J 2016; 15:416. [PMID: 27531359 PMCID: PMC4987995 DOI: 10.1186/s12936-016-1459-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 07/29/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Individuals living in endemic areas gradually acquire natural immunity to clinical malaria, largely dependent on antibodies against parasite antigens. There are many studies indicating that the variant antigen PfEMP1 at the surface of the parasitized red blood cell (pRBC) is one of the major targets of the immune response. It is believed that antibodies against PfEMP1 confer protection by blocking sequestration (rosetting and cytoadherence), inducing antibody-dependent cellular-inhibitory effect and opsonizing pRBCs for phagocytosis. METHODS A recombinant NTS-DBL1α domain from a rosette-mediating PfEMP1 was expressed in Escherichia coli. The resulting protein was purified and used for immunization to generate polyclonal (goat) and monoclonal (mouse) antibodies. The antibodies' ability to opsonize and induce phagocytosis in vitro was tested and contrasted with the presence of opsonizing antibodies naturally acquired during Plasmodium falciparum infection. RESULTS All antibodies recognized the recombinant antigen and the surface of live pRBCs, however, their capacity to opsonize the pRBCs for phagocytosis varied. The monoclonal antibodies isotyped as IgG2b did not induce phagocytosis, while those isotyped as IgG2a were in general very effective, inducing phagocytosis with similar levels as those naturally acquired during P. falciparum infection. These monoclonal antibodies displayed different patterns, some of them showing a concentration-dependent activity while others showed a prozone-like effect. The goat polyclonal antibodies were not able to induce phagocytosis. CONCLUSION Immunization with an NTS-DBL1-α domain of PfEMP1 generates antibodies that not only have a biological role in rosette disruption but also effectively induce opsonization for phagocytosis of pRBCs with similar activity to naturally acquired antibodies from immune individuals living in a malaria endemic area. Some of the antibodies with high opsonizing activity were not able to disrupt rosettes, indicating that epitopes of the NTS-DBL1-α other than those involved in rosetting are exposed on the pRBC surface and are able to induce functional antibodies. The ability to induce phagocytosis largely depended on the antibody isotype and on the ability to recognize the surface of the pRBC regardless of the rosette-disrupting capacity.
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Affiliation(s)
- Maria Del Pilar Quintana
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,Escuela de Medicina y Ciencias de la Salud, Facultad de Ciencias Naturales y Matemáticas, Universidad del Rosario, Bogotá, Colombia
| | - Davide Angeletti
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Kirsten Moll
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden
| | - Qijun Chen
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.,Key Laboratory of Zoonosis, Jilin University, Changchun, People's Republic of China.,Institute of Pathogen Biology, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Stockholm, Sweden.
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Interaction between Endothelial Protein C Receptor and Intercellular Adhesion Molecule 1 to Mediate Binding of Plasmodium falciparum-Infected Erythrocytes to Endothelial Cells. mBio 2016; 7:mBio.00615-16. [PMID: 27406562 PMCID: PMC4958245 DOI: 10.1128/mbio.00615-16] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Intercellular adhesion molecule 1 (ICAM-1) and the endothelial protein C receptor (EPCR) are candidate receptors for the deadly complication cerebral malaria. However, it remains unclear if Plasmodium falciparum parasites with dual binding specificity are involved in cytoadhesion or different parasite subpopulations bind in brain microvessels. Here, we investigated this issue by studying different subtypes of ICAM-1-binding parasite lines. We show that two parasite lines expressing domain cassette 13 (DC13) of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) family have dual binding specificity for EPCR and ICAM-1 and further mapped ICAM-1 binding to the first DBLβ domain following the PfEMP1 head structure in both proteins. As PfEMP1 head structures have diverged between group A (EPCR binders) and groups B and C (CD36 binders), we also investigated how ICAM-1-binding parasites with different coreceptor binding traits influence P. falciparum-infected erythrocyte binding to endothelial cells. Whereas levels of binding to tumor necrosis factor alpha (TNF-α)-stimulated endothelial cells from the lung and brain by all ICAM-1-binding parasite lines increased, group A (EPCR and ICAM-1) was less dependent than group B (CD36 and ICAM-1) on ICAM-1 upregulation. Furthermore, both group A DC13 parasite lines had higher binding levels to brain endothelial cells (a microvascular niche with limited CD36 expression). This study shows that ICAM-1 is a coreceptor for a subset of EPCR-binding parasites and provides the first evidence of how EPCR and ICAM-1 interact to mediate parasite binding to both resting and TNF-α-activated primary brain and lung endothelial cells. Cerebral malaria is a severe neurological complication of P. falciparum infection associated with infected erythrocyte (IE) binding in cerebral vessels. Yet little is known about the mechanisms by which parasites adhere in the brain or other microvascular sites. Here, we studied parasite lines expressing group A DC13-containing PfEMP1 variants, a subset that has previously been shown to have high brain cell- and other endothelial cell-binding activities. We show that DC13-containing PfEMP1 variants have dual EPCR- and ICAM-1-binding activities and that both receptors are involved in parasite adherence to lung and brain endothelial cells. As both EPCR and ICAM-1 are implicated in cerebral malaria, these findings suggest the possibility that parasites with dual binding activities are involved in parasite sequestration to microvascular beds with low CD36 expression, such as the brain, and we urge more research into the multiadhesive properties of PfEMP1 variants.
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63
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Kudella PW, Moll K, Wahlgren M, Wixforth A, Westerhausen C. ARAM: an automated image analysis software to determine rosetting parameters and parasitaemia in Plasmodium samples. Malar J 2016; 15:223. [PMID: 27090910 PMCID: PMC4835829 DOI: 10.1186/s12936-016-1243-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 03/30/2016] [Indexed: 11/14/2022] Open
Abstract
Background Rosetting is associated with severe malaria and a primary cause of death in Plasmodium falciparum infections. Detailed understanding of this adhesive phenomenon may enable the development of new therapies interfering with rosette formation. For this, it is crucial to determine parameters such as rosetting and parasitaemia of laboratory strains or patient isolates, a bottleneck in malaria research due to the time consuming and error prone manual analysis of specimens. Here, the automated, free, stand-alone analysis software automated rosetting analyzer for micrographs (ARAM) to determine rosetting rate, rosette size distribution as well as parasitaemia with a convenient graphical user interface is presented. Methods Automated rosetting analyzer for micrographs is an executable with two operation modes for automated identification of objects on images. The default mode detects red blood cells and fluorescently labelled parasitized red blood cells by combining an intensity-gradient with a threshold filter. The second mode determines object location and size distribution from a single contrast method. The obtained results are compared with standardized manual analysis. Automated rosetting analyzer for micrographs calculates statistical confidence probabilities for rosetting rate and parasitaemia. Results Automated rosetting analyzer for micrographs analyses 25 cell objects per second reliably delivering identical results compared to manual analysis. For the first time rosette size distribution is determined in a precise and quantitative manner employing ARAM in combination with established inhibition tests. Additionally ARAM measures the essential observables parasitaemia, rosetting rate and size as well as location of all detected objects and provides confidence intervals for the determined observables. No other existing software solution offers this range of function. The second, non-malaria specific, analysis mode of ARAM offers the functionality to detect arbitrary objects. Conclusions Automated rosetting analyzer for micrographs has the capability to push malaria research to a more quantitative and statistically significant level with increased reliability due to operator independence. As an installation file for Windows © 7, 8.1 and 10 is available for free, ARAM offers a novel open and easy-to-use platform for the malaria community to elucidate rosetting. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1243-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Kirsten Moll
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Box 280, 171 77, Stockholm, Sweden
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Box 280, 171 77, Stockholm, Sweden
| | - Achim Wixforth
- Experimental Physics I, University of Augsburg, Universitätsstraße 1, Augsburg, Germany.,Nanosystems Initiative Munich, Schellingstraße 4, Munich, Germany
| | - Christoph Westerhausen
- Experimental Physics I, University of Augsburg, Universitätsstraße 1, Augsburg, Germany. .,Nanosystems Initiative Munich, Schellingstraße 4, Munich, Germany.
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64
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Wilairat P, Kümpornsin K, Chookajorn T. Plasmodium falciparum malaria: Convergent evolutionary trajectories towards delayed clearance following artemisinin treatment. Med Hypotheses 2016; 90:19-22. [PMID: 27063079 DOI: 10.1016/j.mehy.2016.02.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 01/26/2016] [Accepted: 02/27/2016] [Indexed: 11/28/2022]
Abstract
Malaria is a major global health challenge with 300million new cases every year. The most effective regimen for treating Plasmodium falciparum malaria is based on artemisinin and its derivatives. The drugs are highly effective, resulting in rapid clearance of parasites even in severe P. falciparum malaria patients. During the last five years, artemisinin-resistant parasites have begun to emerge first in Cambodia and now in Thailand and Myanmar. At present, the level of artemisinin resistance is relatively low with clinical presentation of delayed artemisinin clearance (a longer time to reduce parasite load) and a small decrease in artemisinin sensitivity in cultured isolates. Nevertheless, multiple genetic loci associated with delayed parasite clearance have been reported, but they cannot account for a large portion of cases. Even the most well-studied kelch 13 propeller mutations cannot always predict the outcome of artemisinin treatment in vitro and in vivo. Here we propose that delayed clearance by artemisinin could be the result of convergent evolution, driven by multiple trajectories to overcome artemisinin-induced stress, but precluded to become full blown resistance by high fitness cost. Genetic association studies by several genome-wide approaches reveal linkage disequilibrium between multiple loci and delayed parasite clearance. Genetic manipulations at some of these loci already have resulted in loss in artemisinin sensitivity. The notion presented here is by itself consistent with existing evidence on artemisinin resistance and has the potential to be explored using available genomic data. Most important of all, molecular surveillance of artemisinin resistance based on multi-genic markers could be more informative than relying on any one particular molecular marker.
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Affiliation(s)
- Prapon Wilairat
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Krittikorn Kümpornsin
- Genomics and Evolutionary Medicine Unit (GEM), Center of Excellence in Malaria, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Thanat Chookajorn
- Genomics and Evolutionary Medicine Unit (GEM), Center of Excellence in Malaria, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
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Activated Neutrophils Are Associated with Pediatric Cerebral Malaria Vasculopathy in Malawian Children. mBio 2016; 7:e01300-15. [PMID: 26884431 PMCID: PMC4791846 DOI: 10.1128/mbio.01300-15] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Most patients with cerebral malaria (CM) sustain cerebral microvascular sequestration of Plasmodium falciparum-infected red blood cells (iRBCs). Although many young children are infected with P. falciparum, CM remains a rare outcome; thus, we hypothesized that specific host conditions facilitate iRBC cerebral sequestration. To identify these host factors, we compared the peripheral whole-blood transcriptomes of Malawian children with iRBC cerebral sequestration, identified as malarial-retinopathy-positive CM (Ret+CM), to the transcriptomes of children with CM and no cerebral iRBC sequestration, defined as malarial-retinopathy-negative CM (Ret-CM). Ret+CM was associated with upregulation of 103 gene set pathways, including cytokine, blood coagulation, and extracellular matrix (ECM) pathways (P < 0.01; false-discovery rate [FDR] of <0.05). Neutrophil transcripts were the most highly upregulated individual transcripts in Ret+CM patients. Activated neutrophils can modulate diverse host processes, including the ECM, inflammation, and platelet biology to potentially facilitate parasite sequestration. Therefore, we compared plasma neutrophil proteins and neutrophil chemotaxis between Ret+CM and Ret-CM patients. Plasma levels of human neutrophil elastase, myeloperoxidase, and proteinase 3, but not lactoferrin or lipocalin, were elevated in Ret+CM patients, and neutrophil chemotaxis was impaired, possibly related to increased plasma heme. Neutrophils were rarely seen in CM brain microvasculature autopsy samples, and no neutrophil extracellular traps were found, suggesting that a putative neutrophil effect on endothelial cell biology results from neutrophil soluble factors rather than direct neutrophil cellular tissue effects. Meanwhile, children with Ret-CM had lower levels of inflammation, higher levels of alpha interferon, and upregulation of Toll-like receptor pathways and other host transcriptional pathways, which may represent responses that do not favor cerebral iRBC sequestration. There were approximately 198 million cases of malaria worldwide in 2013, with an estimated 584,000 deaths occurring mostly in sub-Saharan African children. CM is a severe and rare form of Plasmodium falciparum infection and is associated with high rates of mortality and neurological morbidity, despite antimalarial treatment. A greater understanding of the pathophysiology of CM would allow the development of adjunctive therapies to improve clinical outcomes. A hallmark of CM is cerebral microvasculature sequestration of P. falciparum-infected red blood cells (iRBCs), which results in vasculopathy in some patients. Our data provide a global analysis of the host pathways associated with CM and newly identify an association of activated neutrophils with brain iRBC sequestration. Products of activated neutrophils could alter endothelial cell receptors and coagulation to facilitate iRBC adherence. Future studies can now examine the role of neutrophils in CM pathogenesis to improve health outcomes.
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66
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Kumar B, Bhalla V, Singh Bhadoriya RP, Suri CR, Varshney GC. Label-free electrochemical detection of malaria-infected red blood cells. RSC Adv 2016. [DOI: 10.1039/c6ra07665c] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The precise and rapid diagnosis of malaria is key to prevent indiscriminate use of antimalarial drugs and help in timely treatment and management of the disease.
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Affiliation(s)
- Binod Kumar
- CSIR-Institute of Microbial Technology
- Chandigarh-160036
- India
| | | | | | - C. Raman Suri
- CSIR-Institute of Microbial Technology
- Chandigarh-160036
- India
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67
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Moll K, Palmkvist M, Ch'ng J, Kiwuwa MS, Wahlgren M. Evasion of Immunity to Plasmodium falciparum: Rosettes of Blood Group A Impair Recognition of PfEMP1. PLoS One 2015; 10:e0145120. [PMID: 26714011 PMCID: PMC4694710 DOI: 10.1371/journal.pone.0145120] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/28/2015] [Indexed: 11/18/2022] Open
Abstract
The ABO blood group antigens are expressed on erythrocytes but also on endothelial cells, platelets and serum proteins. Notably, the ABO blood group of a malaria patient determines the development of the disease given that blood group O reduces the probability to succumb in severe malaria, compared to individuals of groups A, B or AB. P. falciparum rosetting and sequestration are mediated by PfEMP1, RIFIN and STEVOR, expressed at the surface of the parasitized red blood cell (pRBC). Antibodies to these antigens consequently modify the course of a malaria infection by preventing sequestration and promoting phagocytosis of pRBC. Here we have studied rosetting P. falciparum and present evidence of an immune evasion mechanism not previously recognized. We find the accessibility of antibodies to PfEMP1 at the surface of the pRBC to be reduced when P. falciparum forms rosettes in blood group A RBC, as compared to group O RBC. The pRBC surrounds itself with tightly bound normal RBC that makes PfEMP1 inaccessible to antibodies and clearance by the immune system. Accordingly, pRBC of in vitro cloned P. falciparum devoid of ABO blood group dependent rosetting were equally well detected by anti-PfEMP1 antibodies, independent of the blood group utilized for their propagation. The pathogenic mechanisms underlying the severe forms of malaria may in patients of blood group A depend on the ability of the parasite to mask PfEMP1 from antibody recognition, in so doing evading immune clearance.
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Affiliation(s)
- Kirsten Moll
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Box 280, Nobels väg 16, SE-171 77 Stockholm, Sweden
- * E-mail: (KM); (MW)
| | - Mia Palmkvist
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Box 280, Nobels väg 16, SE-171 77 Stockholm, Sweden
| | - Junhong Ch'ng
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Box 280, Nobels väg 16, SE-171 77 Stockholm, Sweden
| | - Mpungu Steven Kiwuwa
- Department of Pediatrics, School of Medicine, Makerere University College of Health Sciences, Kampala, Uganda
- Department of Biochemistry, School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda
| | - Mats Wahlgren
- Department of Microbiology, Tumor and Cell Biology (MTC), Karolinska Institutet, Box 280, Nobels väg 16, SE-171 77 Stockholm, Sweden
- * E-mail: (KM); (MW)
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Differential Plasmodium falciparum surface antigen expression among children with Malarial Retinopathy. Sci Rep 2015; 5:18034. [PMID: 26657042 PMCID: PMC4677286 DOI: 10.1038/srep18034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 11/10/2015] [Indexed: 11/08/2022] Open
Abstract
Retinopathy provides a window into the underlying pathology of life-threatening malarial coma ("cerebral malaria"), allowing differentiation between 1) coma caused by sequestration of Plasmodium falciparum-infected erythrocytes in the brain and 2) coma with other underlying causes. Parasite sequestration in the brain is mediated by PfEMP1; a diverse parasite antigen that is inserted into the surface of infected erythrocytes and adheres to various host receptors. PfEMP1 sub-groups called "DC8" and "DC13" have been proposed to cause brain pathology through interactions with endothelial protein C receptor. To test this we profiled PfEMP1 gene expression in parasites from children with clinically defined cerebral malaria, who either had or did not have accompanying retinopathy. We found no evidence for an elevation of DC8 or DC13 PfEMP1 expression in children with retinopathy. However, the proportional expression of a broad subgroup of PfEMP1 called "group A" was elevated in retinopathy patients suggesting that these variants may play a role in the pathology of cerebral malaria. Interventions targeting group A PfEMP1 may be effective at reducing brain pathology.
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Deroost K, Pham TT, Opdenakker G, Van den Steen PE. The immunological balance between host and parasite in malaria. FEMS Microbiol Rev 2015; 40:208-57. [PMID: 26657789 DOI: 10.1093/femsre/fuv046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
Coevolution of humans and malaria parasites has generated an intricate balance between the immune system of the host and virulence factors of the parasite, equilibrating maximal parasite transmission with limited host damage. Focusing on the blood stage of the disease, we discuss how the balance between anti-parasite immunity versus immunomodulatory and evasion mechanisms of the parasite may result in parasite clearance or chronic infection without major symptoms, whereas imbalances characterized by excessive parasite growth, exaggerated immune reactions or a combination of both cause severe pathology and death, which is detrimental for both parasite and host. A thorough understanding of the immunological balance of malaria and its relation to other physiological balances in the body is of crucial importance for developing effective interventions to reduce malaria-related morbidity and to diminish fatal outcomes due to severe complications. Therefore, we discuss in this review the detailed mechanisms of anti-malarial immunity, parasite virulence factors including immune evasion mechanisms and pathogenesis. Furthermore, we propose a comprehensive classification of malaria complications according to the different types of imbalances.
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Affiliation(s)
- Katrien Deroost
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium The Francis Crick Institute, Mill Hill Laboratory, London, NW71AA, UK
| | - Thao-Thy Pham
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Philippe E Van den Steen
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
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Differential Spleen Remodeling Associated with Different Levels of Parasite Virulence Controls Disease Outcome in Malaria Parasite Infections. mSphere 2015; 1:mSphere00018-15. [PMID: 27303680 PMCID: PMC4863626 DOI: 10.1128/msphere.00018-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/11/2015] [Indexed: 11/20/2022] Open
Abstract
Infections by malaria parasites can lead to very different clinical outcomes, ranging from mild symptoms to death. Differences in the ability of the spleen to deal with the infected red blood cells (iRBCs) are linked to differences in virulence. Using virulent and avirulent strains of the rodent malaria parasite Plasmodium yoelii, we investigated how parasite virulence modulates overall spleen function. Following parasite invasion, a difference in parasite virulence was observed in association with different levels of spleen morphology and iRBC rigidity, both of which contributed to enhanced parasite clearance. Moreover, iRBC rigidity as modulated by the spleen was demonstrated to correlate with disease outcome and thus can be used as a robust indicator of virulence. The data indicate that alterations in the biomechanical properties of iRBCs are the result of the complex interaction between host and parasite. Furthermore, we confirmed that early spleen responses are a key factor in directing the clinical outcome of an infection. IMPORTANCE The spleen and its response to parasite infection are important in eliminating parasites in malaria. By comparing P. yoelii parasite lines with different disease outcomes in mice that had either intact spleens or had had their spleens removed, we showed that upon parasite infection, the spleen exhibits dramatic changes that can affect parasite clearance. The spleen itself directly impacts RBC deformability independently of parasite genetics. The data indicated that the changes in the biomechanical properties of malaria parasite-infected RBCs are the result of the complex interaction between host and parasite, and RBC deformability itself can serve as a novel predictor of clinical outcome. The results also suggest that early responses in the spleen are a key factor directing the clinical outcome of an infection.
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Plewes K, Maude RJ, Ghose A, Dondorp AM. Severe falciparum malaria complicated by prolonged haemolysis and rhinomaxillary mucormycosis after parasite clearance: a case report. BMC Infect Dis 2015; 15:555. [PMID: 26634340 PMCID: PMC4669602 DOI: 10.1186/s12879-015-1285-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 11/23/2015] [Indexed: 11/13/2022] Open
Abstract
Background Severe falciparum malaria may be complicated by prolonged haemolysis and recurrent fever after parasite clearance. However, their respective etiologies are unclear and challenging to diagnose. We report the first case of severe falciparum malaria followed by prolonged haemolytic anaemia and rhinomaxillary mucormycosis in a previously healthy adult male. Case presentation A 30-year old Bangladeshi man was admitted with severe falciparum malaria complicated by hyperlactataemia and haemoglobinuria. Prior to admission he was treated with intravenous quinine and upon admission received intravenous artesunate and empiric ceftriaxone. Thirty hours later the peripheral parasitaemia cleared with resolution of fever and haemoglobinuria. Despite parasite clearance, on day 3 the patient developed recurrent fever and acute haemolytic anaemia requiring seven blood transfusions over six days with no improvement of his haemoglobin or haemoglobinuria. On day 10, he was treated with high-dose dexamethasone and meropenem with discontinuation of the ceftriaxone. Two days later the haemoglobinuria resolved. Ceftriaxone-induced haemolysis was the suspected final diagnosis. On day 16, the patient had progressively worsening right-sided facial pain and swelling; a necrotic ulceration of the hard palate was observed. Rhinomaxillary mucormycosis was diagnosed supported by microscopy findings. The patient initially responded to treatment with urgent surgical debridement, itraconazole, followed by two weeks of amphotericin B deoxycholate, however was subsequently lost to follow up. Conclusions This case highlights the range of potential alternative aetiologies of acute, prolonged haemolysis and recurrent fever following parasite clearance in severe falciparum malaria. It emphasizes the importance of a high degree of suspicion for alternative causes of haemolysis in order to avoid unnecessary treatments, including blood transfusion and steroids. It is critical to consider and identify common invasive bacterial and rare opportunistic co-infections as a cause of fever in severe malaria patients remaining febrile after parasite clearance to promote antimicrobial stewardship and prompt emergency care.
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Affiliation(s)
- Katherine Plewes
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
| | - Richard J Maude
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
| | - Aniruddha Ghose
- Department of Medicine, Chittagong Medical College Hospital, Chittagong, Bangladesh.
| | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok, 10400, Thailand. .,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom.
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72
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Abstract
Plasmodium falciparum is the protozoan parasite that causes most malaria-associated morbidity and mortality in humans with over 500,000 deaths annually. The disease symptoms are associated with repeated cycles of invasion and asexual multiplication inside red blood cells of the parasite. Partial, non-sterile immunity to P. falciparum malaria develops only after repeated infections and continuous exposure. The successful evasion of the human immune system relies on the large repertoire of antigenically diverse parasite proteins displayed on the red blood cell surface and on the merozoite membrane where they are exposed to the human immune system. Expression switching of these polymorphic proteins between asexual parasite generations provides an efficient mechanism to adapt to the changing environment in the host and to maintain chronic infection. This chapter discusses antigenic diversity and variation in the malaria parasite and our current understanding of the molecular mechanisms that direct the expression of these proteins.
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Affiliation(s)
- Michaela Petter
- Department of Medicine Royal Melbourne Hospital, Peter Doherty Institute, University of Melbourne, 792 Elizabeth Street, Melbourne, VIC, 3010, Australia.
| | - Michael F Duffy
- Department of Medicine Royal Melbourne Hospital, Peter Doherty Institute, University of Melbourne, 792 Elizabeth Street, Melbourne, VIC, 3010, Australia.
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73
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Ishioka H, Ghose A, Charunwatthana P, Maude R, Plewes K, Kingston H, Intharabut B, Woodrow C, Chotivanich K, Sayeed AA, Hasan MU, Day NP, Faiz A, White NJ, Hossain A, Dondorp AM. Sequestration and Red Cell Deformability as Determinants of Hyperlactatemia in Falciparum Malaria. J Infect Dis 2015; 213:788-93. [PMID: 26494775 PMCID: PMC4747623 DOI: 10.1093/infdis/jiv502] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 10/13/2015] [Indexed: 11/17/2022] Open
Abstract
Background. Hyperlactatemia is a strong predictor of mortality in severe falciparum malaria. Sequestered parasitized erythrocytes and reduced uninfected red blood cell deformability (RCD) compromise microcirculatory flow, leading to anaerobic glycolysis. Methods. In a cohort of patients with falciparum malaria hospitalized in Chittagong, Bangladesh, bulk RCD was measured using a laser diffraction technique, and parasite biomass was estimated from plasma concentrations of Plasmodium falciparum histidine-rich protein 2 (PfHRP2). A multiple linear regression model was constructed to examine their associations with plasma lactate concentrations. Results. A total of 286 patients with falciparum malaria were studied, of whom 224 had severe malaria, and 70 died. Hyperlactatemia (lactate level, ≥4 mmol/L) was present in 111 cases. RCD at shear stresses of 1.7 Pa and 30 Pa was reduced significantly in patients who died, compared with survivors, individuals with uncomplicated malaria, or healthy individuals (P < .05, for all comparisons). Multiple linear regression analysis showed that the plasma PfHRP2 level, parasitemia level, total bilirubin level, and RCD at a shear stress of 1.7 Pa were each independently correlated with plasma lactate concentrations (n = 278; R2 = 0.35). Conclusions. Sequestration of parasitized red blood cells and reduced RCD both contribute to decreased microcirculatory flow in severe disease.
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Affiliation(s)
- Haruhiko Ishioka
- Mahidol Oxford Tropical Medicine Research Unit Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | - Prakaykaew Charunwatthana
- Mahidol Oxford Tropical Medicine Research Unit Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Richard Maude
- Mahidol Oxford Tropical Medicine Research Unit Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
| | | | | | | | - Charlie Woodrow
- Mahidol Oxford Tropical Medicine Research Unit Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
| | - Kesinee Chotivanich
- Mahidol Oxford Tropical Medicine Research Unit Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Nicholas P Day
- Mahidol Oxford Tropical Medicine Research Unit Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
| | - Abul Faiz
- Mahidol Oxford Tropical Medicine Research Unit Malaria Research Group and Dev Care Foundation, Dhaka, Bangladesh
| | - Nicholas J White
- Mahidol Oxford Tropical Medicine Research Unit Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
| | | | - Arjen M Dondorp
- Mahidol Oxford Tropical Medicine Research Unit Nuffield Department of Clinical Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, United Kingdom
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74
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Eisenhut M. The evidence for a role of vasospasm in the pathogenesis of cerebral malaria. Malar J 2015; 14:405. [PMID: 26463364 PMCID: PMC4603731 DOI: 10.1186/s12936-015-0928-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/01/2015] [Indexed: 12/31/2022] Open
Abstract
Due to delay in treatment, cerebral malaria (CM) remains a significant complication of Plasmodium falciparum infection and is a common cause of death from malaria. In addition, more than 10 % of children surviving CM have neurological and long-term cognitive deficits. Understanding the pathogenesis of CM enables design of supportive treatment, reducing neurological morbidity and mortality. Vaso-occlusion and brain swelling appear to be leading to clinical features, neuronal damage and death in CM. It is proposed that parasitized red blood cells (pRBC), due to cytoadhesion to the endothelium and vasospasm induced by reduced bioavailability of nitric oxide, are causes. Stasis of blood flow and accumulation of pRBC may allow, after schizont rupture, for high concentration of products of haemolysis to accumulate, which leads to localized nitric oxide depletion, inducing adhesion molecules and cerebral vasospasm. Features consistent with an involvement of vasospasm are rapid reversibility of neurological symptoms, intermittently increased or absent flow in medium cerebral artery detectable on Doppler ultrasound and hemispheric reversible changes on cerebral magnetic resonance imaging in some patients. Clinical trials of treatment that can rapidly reduce cerebral vasospasm, including nitric oxide donors, inhaled nitric oxide, endothelin or calcium antagonists, or tissue plasminogen activators, are warranted.
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Affiliation(s)
- Michael Eisenhut
- Luton and Dunstable University Hospital NHS Foundation Trust, Lewsey Road, Luton, LU4ODZ, UK.
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75
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Carvalho LJDM, Moreira ADS, Daniel-Ribeiro CT, Martins YC. Vascular dysfunction as a target for adjuvant therapy in cerebral malaria. Mem Inst Oswaldo Cruz 2015; 109:577-88. [PMID: 25185000 PMCID: PMC4156451 DOI: 10.1590/0074-0276140061] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 04/02/2014] [Indexed: 12/27/2022] Open
Abstract
Cerebral malaria (CM) is a life-threatening complication of Plasmodium
falciparum malaria that continues to be a major global health problem.
Brain vascular dysfunction is a main factor underlying the pathogenesis of CM and can
be a target for the development of adjuvant therapies for the disease. Vascular
occlusion by parasitised red blood cells and vasoconstriction/vascular dysfunction
results in impaired cerebral blood flow, ischaemia, hypoxia, acidosis and death. In
this review, we discuss the mechanisms of vascular dysfunction in CM and the roles of
low nitric oxide bioavailability, high levels of endothelin-1 and dysfunction of the
angiopoietin-Tie2 axis. We also discuss the usefulness and relevance of the murine
experimental model of CM by Plasmodium berghei ANKA to identify
mechanisms of disease and to screen potential therapeutic interventions.
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Affiliation(s)
| | - Aline da Silva Moreira
- Laboratório de Pesquisas em Malária, Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, RJ, Brasil
| | | | - Yuri Chaves Martins
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
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76
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Lennartz F, Bengtsson A, Olsen RW, Joergensen L, Brown A, Remy L, Man P, Forest E, Barfod LK, Adams Y, Higgins MK, Jensen ATR. Mapping the Binding Site of a Cross-Reactive Plasmodium falciparum PfEMP1 Monoclonal Antibody Inhibitory of ICAM-1 Binding. THE JOURNAL OF IMMUNOLOGY 2015; 195:3273-83. [PMID: 26320251 PMCID: PMC4574524 DOI: 10.4049/jimmunol.1501404] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 07/23/2015] [Indexed: 12/29/2022]
Abstract
The virulence of Plasmodium falciparum is linked to the ability of infected erythrocytes (IE) to adhere to the vascular endothelium, mediated by P. falciparum erythrocyte membrane protein 1 (PfEMP1). In this article, we report the functional characterization of an mAb that recognizes a panel of PfEMP1s and inhibits ICAM-1 binding. The 24E9 mouse mAb was raised against PFD1235w DBLβ3_D4, a domain from the group A PfEMP1s associated with severe malaria. 24E9 recognizes native PfEMP1 expressed on the IE surface and shows cross-reactivity with and cross-inhibition of the ICAM-1 binding capacity of domain cassette 4 PfEMP1s. 24E9 Fab fragments bind DBLβ3_D4 with nanomolar affinity and inhibit ICAM-1 binding of domain cassette 4–expressing IE. The antigenic regions targeted by 24E9 Fab were identified by hydrogen/deuterium exchange mass spectrometry and revealed three discrete peptides that are solvent protected in the complex. When mapped onto a homology model of DBLβ3_D4, these cluster to a defined, surface-exposed region on the convex surface of DBLβ3_D4. Mutagenesis confirmed that the site most strongly protected is necessary for 24E9 binding, which is consistent with a low-resolution structure of the DBLβ3_D4::24E9 Fab complex derived from small-angle x-ray scattering. The convex surface of DBLβ3_D4 has previously been shown to contain the ICAM-1 binding site of DBLβ domains, suggesting that the mAb acts by occluding the ICAM-1 binding surface. Conserved epitopes, such as those targeted by 24E9, are promising candidates for the inclusion in a vaccine interfering with ICAM-1–specific adhesion of group A PfEMP1 expressed by P. falciparum IE during severe malaria.
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Affiliation(s)
- Frank Lennartz
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Anja Bengtsson
- Department of Immunology and Microbiology, Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 1014, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen 2100, Denmark
| | - Rebecca W Olsen
- Department of Immunology and Microbiology, Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 1014, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen 2100, Denmark
| | - Louise Joergensen
- Department of Immunology and Microbiology, Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 1014, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen 2100, Denmark
| | - Alan Brown
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, United Kingdom
| | - Louise Remy
- Institut de Biologie Structurale, Grenoble F-38044, France
| | - Petr Man
- Institute of Microbiology, Academy of Sciences of the Czech Republic, 117 20 Prague, Czech Republic; and Faculty of Science, Charles University in Prague, 116 36 Prague, Czech Republic
| | - Eric Forest
- Institut de Biologie Structurale, Grenoble F-38044, France
| | - Lea K Barfod
- Department of Immunology and Microbiology, Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 1014, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen 2100, Denmark
| | - Yvonne Adams
- Department of Immunology and Microbiology, Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 1014, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen 2100, Denmark
| | - Matthew K Higgins
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom;
| | - Anja T R Jensen
- Department of Immunology and Microbiology, Centre for Medical Parasitology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 1014, Denmark; Department of Infectious Diseases, Copenhagen University Hospital (Rigshospitalet), Copenhagen 2100, Denmark;
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77
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Kimoloi S, Rashid K. Potential role of Plasmodium falciparum-derived ammonia in the pathogenesis of cerebral malaria. Front Neurosci 2015; 9:234. [PMID: 26190968 PMCID: PMC4490226 DOI: 10.3389/fnins.2015.00234] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 06/18/2015] [Indexed: 12/19/2022] Open
Abstract
Cerebral malaria (CM) is the most severe complication associated with Plasmodium falciparum infection. The exact pathogenic mechanisms leading to the development of CM remains poorly understood while the mortality rates remain high. Several potential mechanisms including mechanical obstruction of brain microvasculature, inflammation, oxidative stress, cerebral energy defects, and hemostatic dysfunction have been suggested to play a role in CM pathogenesis. However, these proposed mechanisms, even when considered together, do not fully explain the pathogenesis and clinicopathological features of human CM. This necessitates consideration of alternative pathogenic mechanisms. P. falciparum generates substantial amounts of ammonia as a catabolic by-product, but lacks detoxification mechanisms. Whether this parasite-derived ammonia plays a pathogenic role in CM is presently unknown, despite its potential to cause localized brain ammonia elevation and subsequent neurotoxic effects. This article therefore, explores and proposes a potential role of parasite-derived ammonia in the pathogenesis and neuropathology of CM. A consideration of parasite-derived ammonia as a factor in CM pathogenesis provides plausible explanations of the various features observed in CM patients including how a largely intravascular parasite can cause neuronal dysfunction. It also provides a framework for rational development and testing of novel drugs targeting the parasite's ammonia handling.
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Affiliation(s)
- Sammy Kimoloi
- Department of Medical Laboratory Sciences, Masinde Muliro University of Science and Technology Kakamega, Kenya
| | - Khalid Rashid
- Biochemistry and Molecular Biology Department, Egerton University Nakuru, Kenya
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78
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Castillo P, Ussene E, Ismail MR, Jordao D, Lovane L, Carrilho C, Lorenzoni C, Lacerda MV, Palhares A, Rodríguez-Carunchio L, Martínez MJ, Vila J, Bassat Q, Menéndez C, Ordi J. Pathological Methods Applied to the Investigation of Causes of Death in Developing Countries: Minimally Invasive Autopsy Approach. PLoS One 2015; 10:e0132057. [PMID: 26126191 PMCID: PMC4488344 DOI: 10.1371/journal.pone.0132057] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/09/2015] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND AND AIMS Complete diagnostic autopsies (CDA) remain the gold standard in the determination of cause of death (CoD). However, performing CDAs in developing countries is challenging due to limited facilities and human resources, and poor acceptability. We aimed to develop and test a simplified minimally invasive autopsy (MIA) procedure involving organ-directed sampling with microbiology and pathology analyses implementable by trained technicians in low- income settings. METHODS A standardized scheme for the MIA has been developed and tested in a series of 30 autopsies performed at the Maputo Central Hospital, Mozambique. The procedure involves the collection of 20 mL of blood and cerebrospinal fluid (CSF) and puncture of liver, lungs, heart, spleen, kidneys, bone marrow and brain in all cases plus uterus in women of childbearing age, using biopsy needles. RESULTS The sampling success ranged from 67% for the kidney to 100% for blood, CSF, lung, liver and brain. The amount of tissue obtained in the procedure varied from less than 10 mm2 for the lung, spleen and kidney, to over 35 mm2 for the liver and brain. A CoD was identified in the histological and/or the microbiological analysis in 83% of the MIAs. CONCLUSIONS A simplified MIA technique allows obtaining adequate material from body fluids and major organs leading to accurate diagnoses. This procedure could improve the determination of CoD in developing countries.
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Affiliation(s)
- Paola Castillo
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Esperança Ussene
- Department of Pathology, Maputo Central Hospital, Maputo, Mozambique
| | - Mamudo R. Ismail
- Department of Pathology, Maputo Central Hospital, Maputo, Mozambique
| | - Dercio Jordao
- Department of Pathology, Maputo Central Hospital, Maputo, Mozambique
| | - Lucilia Lovane
- Department of Pathology, Maputo Central Hospital, Maputo, Mozambique
| | - Carla Carrilho
- Department of Pathology, Maputo Central Hospital, Maputo, Mozambique
| | | | - Marcus V. Lacerda
- Fundação de Medicina Tropical Dr. Heitor Viera Dourado, Manaus, Amazonas, Brazil
| | - Antonio Palhares
- Fundação de Medicina Tropical Dr. Heitor Viera Dourado, Manaus, Amazonas, Brazil
| | | | - Miguel J. Martínez
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
- Department of Microbiology, Hospital Clinic, Universitat de Barcelona, Spain
| | - Jordi Vila
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
- Department of Microbiology, Hospital Clinic, Universitat de Barcelona, Spain
| | - Quique Bassat
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça, (CISM), Maputo, Mozambique
| | - Clara Menéndez
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça, (CISM), Maputo, Mozambique
| | - Jaume Ordi
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
- Department of Pathology, Hospital Clinic, Universitat de Barcelona, Spain
- * E-mail:
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79
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Hanson J, Lee SJ, Hossain MA, Anstey NM, Charunwatthana P, Maude RJ, Kingston HWF, Mishra SK, Mohanty S, Plewes K, Piera K, Hassan MU, Ghose A, Faiz MA, White NJ, Day NPJ, Dondorp AM. Microvascular obstruction and endothelial activation are independently associated with the clinical manifestations of severe falciparum malaria in adults: an observational study. BMC Med 2015; 13:122. [PMID: 26018532 PMCID: PMC4453275 DOI: 10.1186/s12916-015-0365-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 05/12/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Microvascular obstruction and endothelial dysfunction have both been linked to tissue hypoperfusion in falciparum malaria, but their relative contributions to the disease's pathogenesis and outcome are unknown. METHODS Microvascular blood flow was quantified in adults with severe falciparum malaria on their admission to hospital; plasma biomarkers of endothelial function were measured simultaneously. The relationship between these indices and the patients' clinical findings and in-hospital course was examined. RESULTS Microvascular obstruction was observed in 119/142 (84 %) patients; a median (interquartile range (IQR)) of 14.9 % (6.6-34.9 %) of capillaries were obstructed in patients that died versus 8.3 % (1.7-26.6 %) in survivors (P = 0.039). The proportion of obstructed capillaries correlated with the estimated parasite biomass (rs = 0.25, P = 0.004) and with plasma lactate (rs = 0.38, P <0.0001), the strongest predictor of death in the series. Plasma angiopoietin-2 (Ang-2) concentrations were markedly elevated suggesting widespread endothelial activation; the median (IQR) Ang-2 concentration was 21.9 ng/mL (13.4-29.4 ng/mL) in patients that died versus 14.9 ng/mL (9.8-29.3 ng/mL) in survivors (P = 0.035). Ang-2 concentrations correlated with estimated parasite biomass (rs = 0.35, P <0.001) and plasma lactate (rs = 0.37, P <0.0001). Microvascular obstruction and Ang-2 concentrations were not significantly correlated with each other (rs = 0.17, P = 0.06), but were independently associated with plasma lactate (P <0.001 and P = 0.002, respectively). CONCLUSIONS Microvascular obstruction and systemic endothelial activation are independently associated with plasma lactate, the strongest predictor of death in adults with falciparum malaria. This supports the hypothesis that the two processes make an independent contribution to the pathogenesis and clinical manifestations of the disease.
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Affiliation(s)
- Josh Hanson
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Global Health Division, Menzies School of Health Research, Darwin, Australia.
| | - Sue J Lee
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Md Amir Hossain
- Department of Medicine, Chittagong Medical College Hospital, Chittagong, Bangladesh.
| | - Nicholas M Anstey
- Global Health Division, Menzies School of Health Research, Darwin, Australia.
| | - Prakaykaew Charunwatthana
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Richard J Maude
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Hugh W F Kingston
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Global Health Division, Menzies School of Health Research, Darwin, Australia.
| | - Saroj K Mishra
- Department of Medicine, Ispat Hospital, Rourkela, Orissa, India.
| | - Sanjib Mohanty
- Department of Medicine, Ispat Hospital, Rourkela, Orissa, India.
| | - Katherine Plewes
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Kim Piera
- Global Health Division, Menzies School of Health Research, Darwin, Australia.
| | - Mahtab U Hassan
- Department of Medicine, Chittagong Medical College Hospital, Chittagong, Bangladesh.
| | - Aniruddha Ghose
- Department of Medicine, Chittagong Medical College Hospital, Chittagong, Bangladesh.
| | - M Abul Faiz
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Specialized Care and Research, Chittagong, Bangladesh. .,Dev Care Foundation, Dhaka, Bangladesh.
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
| | - Arjen M Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. .,Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK.
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80
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Milner DA, Lee JJ, Frantzreb C, Whitten RO, Kamiza S, Carr RA, Pradham A, Factor RE, Playforth K, Liomba G, Dzamalala C, Seydel KB, Molyneux ME, Taylor TE. Quantitative Assessment of Multiorgan Sequestration of Parasites in Fatal Pediatric Cerebral Malaria. J Infect Dis 2015; 212:1317-21. [PMID: 25852120 DOI: 10.1093/infdis/jiv205] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 03/19/2015] [Indexed: 01/08/2023] Open
Abstract
Children in sub-Saharan Africa continue to acquire and die from cerebral malaria, despite efforts to control or eliminate the causative agent, Plasmodium falciparum. We present a quantitative histopathological assessment of the sequestration of parasitized erythrocytes in multiple organs obtained during a prospective series of 103 autopsies performed between 1996 and 2010 in Blantyre, Malawi, on pediatric patients who died from cerebral malaria and controls. After the brain, sequestration of parasites was most intense in the gastrointestinal tract, both in patients with cerebral malaria and those with parasitemia in other organs. Within cases of histologically defined cerebral malaria, which includes phenotypes termed "sequestration only" (CM1) and "sequestration with extravascular pathology" (CM2), CM1 was associated with large parasite numbers in the spleen and CM2 with intense parasite sequestration in the skin. A striking histological finding overall was the marked sequestration of parasitized erythrocytes across most organs in patients with fatal cerebral malaria, supporting the hypothesis that the disease is, in part, a result of a high level of total-body parasite sequestration.
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Affiliation(s)
- Danny A Milner
- Department of Pathology, Brigham and Women's Hospital Department of Immunology and Infectious Disease, Harvard School of Public Health, Boston, Massachusetts Blantyre Malaria Project, University of Malawi College of Medicine
| | | | | | | | | | - Richard A Carr
- Department of Histopathology, South Warwickshire General Hospitals, Warwick
| | - Alana Pradham
- Department of Pathology, Brigham and Women's Hospital
| | | | | | | | | | - Karl B Seydel
- College of Osteopathic Medicine, Michigan State University, East Lansing Blantyre Malaria Project, University of Malawi College of Medicine
| | - Malcolm E Molyneux
- University of Malawi, College of Medicine Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Blantyre, Malawi Liverpool School of Tropical Medicine, University of Liverpool, United Kingdom
| | - Terrie E Taylor
- College of Osteopathic Medicine, Michigan State University, East Lansing Blantyre Malaria Project, University of Malawi College of Medicine
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81
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Infección placentaria por malaria. CLINICA E INVESTIGACION EN GINECOLOGIA Y OBSTETRICIA 2015. [DOI: 10.1016/j.gine.2013.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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82
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Rubach MP, Mukemba J, Florence S, Lopansri BK, Hyland K, Volkheimer AD, Yeo TW, Anstey NM, Weinberg JB, Mwaikambo ED, Granger DL. Impaired systemic tetrahydrobiopterin bioavailability and increased oxidized biopterins in pediatric falciparum malaria: association with disease severity. PLoS Pathog 2015; 11:e1004655. [PMID: 25764173 PMCID: PMC4357384 DOI: 10.1371/journal.ppat.1004655] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 01/05/2015] [Indexed: 12/17/2022] Open
Abstract
Decreased bioavailability of nitric oxide (NO) is a major contributor to the pathophysiology of severe falciparum malaria. Tetrahydrobiopterin (BH4) is an enzyme cofactor required for NO synthesis from L-arginine. We hypothesized that systemic levels of BH₄ would be decreased in children with cerebral malaria, contributing to low NO bioavailability. In an observational study in Tanzania, we measured urine levels of biopterin in its various redox states (fully reduced [BH₄] and the oxidized metabolites, dihydrobiopterin [BH₂] and biopterin [B₀]) in children with uncomplicated malaria (UM, n = 55), cerebral malaria (CM, n = 45), non-malaria central nervous system conditions (NMC, n = 48), and in 111 healthy controls (HC). Median urine BH4 concentration in CM (1.10 [IQR:0.55-2.18] μmol/mmol creatinine) was significantly lower compared to each of the other three groups - UM (2.10 [IQR:1.32-3.14];p<0.001), NMC (1.52 [IQR:1.01-2.71];p = 0.002), and HC (1.60 [IQR:1.15-2.23];p = 0.005). Oxidized biopterins were increased, and the BH4:BH2 ratio markedly decreased in CM. In a multivariate logistic regression model, each Log10-unit decrease in urine BH4 was independently associated with a 3.85-fold (95% CI:1.89-7.61) increase in odds of CM (p<0.001). Low systemic BH4 levels and increased oxidized biopterins contribute to the low NO bioavailability observed in CM. Adjunctive therapy to regenerate BH4 may have a role in improving NO bioavailability and microvascular perfusion in severe falciparum malaria.
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Affiliation(s)
- Matthew P. Rubach
- Department of Medicine, Duke University and VA Medical Centers, Durham, North Carolina, United States of America
| | - Jackson Mukemba
- Department of Pediatrics, Hubert Kairuki Memorial University, Dar es Salaam, United Republic of Tanzania
| | - Salvatore Florence
- Department of Pediatrics, Hubert Kairuki Memorial University, Dar es Salaam, United Republic of Tanzania
| | - Bert K. Lopansri
- Department of Medicine, Intermountain Healthcare, Salt Lake City, Utah, United States of America
- Department of Medicine, University of Utah School of Medicine and VA Medical Center, Salt Lake City, Utah, United States of America
| | - Keith Hyland
- Neurochemistry Division, Medical Neurogenetics, Atlanta, Georgia, United States of America
| | - Alicia D. Volkheimer
- Department of Medicine, Duke University and VA Medical Centers, Durham, North Carolina, United States of America
| | - Tsin W. Yeo
- Global and Tropical Health Division, Menzies School for Health Research and Charles Darwin University, Darwin, Australia
- Division of Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia
- Department of Medicine, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Nicholas M. Anstey
- Global and Tropical Health Division, Menzies School for Health Research and Charles Darwin University, Darwin, Australia
- Division of Medicine, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| | - J. Brice Weinberg
- Department of Medicine, Duke University and VA Medical Centers, Durham, North Carolina, United States of America
| | - Esther D. Mwaikambo
- Department of Pediatrics, Hubert Kairuki Memorial University, Dar es Salaam, United Republic of Tanzania
| | - Donald L. Granger
- Department of Medicine, University of Utah School of Medicine and VA Medical Center, Salt Lake City, Utah, United States of America
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Kilian N, Srismith S, Dittmer M, Ouermi D, Bisseye C, Simpore J, Cyrklaff M, Sanchez CP, Lanzer M. Hemoglobin S and C affect protein export in Plasmodium falciparum-infected erythrocytes. Biol Open 2015; 4:400-10. [PMID: 25701664 PMCID: PMC4359745 DOI: 10.1242/bio.201410942] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Malaria is a potentially deadly disease. However, not every infected person develops severe symptoms. Some people are protected by naturally occurring mechanisms that frequently involve inheritable modifications in their hemoglobin. The best studied protective hemoglobins are the sickle cell hemoglobin (HbS) and hemoglobin C (HbC) which both result from a single amino acid substitution in β-globin: glutamic acid at position 6 is replaced by valine or lysine, respectively. How these hemoglobinopathies protect from severe malaria is only partly understood. Models currently proposed in the literature include reduced disease-mediating cytoadherence of parasitized hemoglobinopathic erythrocytes, impaired intraerythrocytic development of the parasite, dampened inflammatory responses, or a combination thereof. Using a conditional protein export system and tightly synchronized Plasmodium falciparum cultures, we now show that export of parasite-encoded proteins across the parasitophorous vacuolar membrane is delayed, slower, and reduced in amount in hemoglobinopathic erythrocytes as compared to parasitized wild type red blood cells. Impaired protein export affects proteins targeted to the host cell cytoplasm, Maurer's clefts, and the host cell plasma membrane. Impaired protein export into the host cell compartment provides a mechanistic explanation for the reduced cytoadherence phenotype associated with parasitized hemoglobinopathic erythrocytes.
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Affiliation(s)
- Nicole Kilian
- Center of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Sirikamol Srismith
- Center of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Martin Dittmer
- Center of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Djeneba Ouermi
- Biomolecular Research Center Pietro Annigoni, University of Ouagadougou, 01 BP 364 Ouagadougou, Burkina Faso
| | - Cyrille Bisseye
- Biomolecular Research Center Pietro Annigoni, University of Ouagadougou, 01 BP 364 Ouagadougou, Burkina Faso
| | - Jacques Simpore
- Biomolecular Research Center Pietro Annigoni, University of Ouagadougou, 01 BP 364 Ouagadougou, Burkina Faso
| | - Marek Cyrklaff
- Center of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Cecilia P Sanchez
- Center of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Michael Lanzer
- Center of Infectious Diseases, Parasitology, Heidelberg University, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
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84
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Malaria induces anemia through CD8+ T cell-dependent parasite clearance and erythrocyte removal in the spleen. mBio 2015; 6:mBio.02493-14. [PMID: 25604792 PMCID: PMC4324318 DOI: 10.1128/mbio.02493-14] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED Severe malarial anemia (SMA) in semi-immune individuals eliminates both infected and uninfected erythrocytes and is a frequent fatal complication. It is proportional not to circulating parasitemia but total parasite mass (sequestered) in the organs. Thus, immune responses that clear parasites in organs may trigger changes leading to anemia. Here, we use an outbred-rat model where increasing parasite removal in the spleen escalated uninfected-erythrocyte removal. Splenic parasite clearance was associated with activated CD8(+) T cells, immunodepletion of which prevented parasite clearance. CD8(+) T cell repletion and concomitant reduction of the parasite load was associated with exacerbated (40 to 60%) hemoglobin loss and changes in properties of uninfected erythrocytes. Together, these data suggest that CD8(+) T cell-dependent parasite clearance causes erythrocyte removal in the spleen and thus anemia. In children infected with the human malaria parasite Plasmodium falciparum, elevation of parasite biomass (not the number of circulating parasites) increased the odds ratio for SMA by 3.5-fold (95% confidence intervals [CI95%], 1.8- to 7.5-fold). CD8(+) T cell expansion/activation independently increased the odds ratio by 2.4-fold (CI95%, 1.0- to 5.7-fold). Concomitant increases in both conferred a 7-fold (CI95%, 1.9- to 27.4-fold)-greater risk for SMA. Together, these data suggest that CD8(+)-dependent parasite clearance may predispose individuals to uninfected-erythrocyte loss and SMA, thus informing severe disease diagnosis and strategies for vaccine development. IMPORTANCE Malaria is a major global health problem. Severe malaria anemia (SMA) is a complex disease associated with partial immunity. Rapid hemoglobin reductions of 20 to 50% are commonly observed and must be rescued by transfusion (which can carry a risk of HIV acquisition). The causes and risk factors of SMA remain poorly understood. Recent studies suggest that SMA is linked to parasite biomass sequestered in organs. This led us to investigate whether immune mechanisms that clear parasites in organs trigger anemia. In rats, erythropoiesis is largely restricted to the bone marrow, and critical aspects of the spleen expected to be important in anemia are similar to those in humans. Therefore, using a rat model, we show that severe anemia is caused through CD8(+) T cell-dependent parasite clearance and erythrocyte removal in the spleen. CD8 activation may also be a new risk factor for SMA in African children.
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Roncalés M, Vidal J, Torres PA, Herreros E. <i>In Vitro</i > Culture of <i>Plasmodium falciparum</i>: Obtention of Synchronous Asexual Erythrocytic Stages. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/ojepi.2015.51010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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86
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Nacer A, Movila A, Sohet F, Girgis NM, Gundra UM, Loke P, Daneman R, Frevert U. Experimental cerebral malaria pathogenesis--hemodynamics at the blood brain barrier. PLoS Pathog 2014; 10:e1004528. [PMID: 25474413 PMCID: PMC4256476 DOI: 10.1371/journal.ppat.1004528] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 10/17/2014] [Indexed: 12/16/2022] Open
Abstract
Cerebral malaria claims the lives of over 600,000 African children every year. To better understand the pathogenesis of this devastating disease, we compared the cellular dynamics in the cortical microvasculature between two infection models, Plasmodium berghei ANKA (PbA) infected CBA/CaJ mice, which develop experimental cerebral malaria (ECM), and P. yoelii 17XL (PyXL) infected mice, which succumb to malarial hyperparasitemia without neurological impairment. Using a combination of intravital imaging and flow cytometry, we show that significantly more CD8(+) T cells, neutrophils, and macrophages are recruited to postcapillary venules during ECM compared to hyperparasitemia. ECM correlated with ICAM-1 upregulation on macrophages, while vascular endothelia upregulated ICAM-1 during ECM and hyperparasitemia. The arrest of large numbers of leukocytes in postcapillary and larger venules caused microrheological alterations that significantly restricted the venous blood flow. Treatment with FTY720, which inhibits vascular leakage, neurological signs, and death from ECM, prevented the recruitment of a subpopulation of CD45(hi) CD8(+) T cells, ICAM-1(+) macrophages, and neutrophils to postcapillary venules. FTY720 had no effect on the ECM-associated expression of the pattern recognition receptor CD14 in postcapillary venules suggesting that endothelial activation is insufficient to cause vascular pathology. Expression of the endothelial tight junction proteins claudin-5, occludin, and ZO-1 in the cerebral cortex and cerebellum of PbA-infected mice with ECM was unaltered compared to FTY720-treated PbA-infected mice or PyXL-infected mice with hyperparasitemia. Thus, blood brain barrier opening does not involve endothelial injury and is likely reversible, consistent with the rapid recovery of many patients with CM. We conclude that the ECM-associated recruitment of large numbers of activated leukocytes, in particular CD8(+) T cells and ICAM(+) macrophages, causes a severe restriction in the venous blood efflux from the brain, which exacerbates the vasogenic edema and increases the intracranial pressure. Thus, death from ECM could potentially occur as a consequence of intracranial hypertension.
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Affiliation(s)
- Adéla Nacer
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Alexandru Movila
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Fabien Sohet
- Department of Anatomy, University of California San Francisco, San Francisco, California, United States of America
| | - Natasha M. Girgis
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Uma Mahesh Gundra
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - P'ng Loke
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Richard Daneman
- Department of Anatomy, University of California San Francisco, San Francisco, California, United States of America
| | - Ute Frevert
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
- * E-mail:
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87
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Frevert U, Nacer A. Fatal cerebral malaria: a venous efflux problem. Front Cell Infect Microbiol 2014; 4:155. [PMID: 25414834 PMCID: PMC4222339 DOI: 10.3389/fcimb.2014.00155] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 10/13/2014] [Indexed: 12/20/2022] Open
Abstract
Most Plasmodium falciparum-infected children with cerebral malaria (CM) die from respiratory arrest, but the underlying pathology is unclear. Here we present a model in which the ultimate cause of death from CM is severe intracranial hypertension. Dynamic imaging of mice infected with P. berghei ANKA, an accepted model for experimental CM, revealed that leukocyte adhesion impairs the venous blood flow by reducing the functional lumen of postcapillary venules (PCV). The resulting increase in intracranial pressure (ICP) exacerbates cerebral edema formation, a hallmark of both murine and pediatric CM. We propose that two entirely different pathogenetic mechanisms-cytoadherence of P. falciparum-infected erythrocytes in pediatric CM and leukocyte arrest in murine CM-result in the same pathological outcome: a severe increase in ICP leading to brainstem herniation and death from respiratory arrest. The intracranial hypertension (IH) model unifies previous hypotheses, applies to human and experimental CM alike, eliminates the need to explain any selective recognition mechanism Plasmodium might use to target multiple sensitive sites in the brain, and explains how an intravascular parasite can cause so much neuronal dysfunction.
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Affiliation(s)
- Ute Frevert
- Division of Medical Parasitology, Department of Microbiology, New York University School of Medicine New York, NY, USA
| | - Adéla Nacer
- Unité de Biologie des Interactions Hôte-Parasite, Département de Parasitologie et Mycologie, Institut Pasteur Paris, France
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88
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89
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Barrera V, Hiscott PS, Craig AG, White VA, Milner DA, Beare NAV, MacCormick IJC, Kamiza S, Taylor TE, Molyneux ME, Harding SP. Severity of retinopathy parallels the degree of parasite sequestration in the eyes and brains of malawian children with fatal cerebral malaria. J Infect Dis 2014; 211:1977-86. [PMID: 25351204 PMCID: PMC4442623 DOI: 10.1093/infdis/jiu592] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/10/2014] [Indexed: 11/17/2022] Open
Abstract
Background. Malarial retinopathy (MR) has diagnostic and prognostic value in children with Plasmodium falciparum cerebral malaria (CM). A clinicopathological correlation between observed retinal changes during life and the degree of sequestration of parasitized red blood cells was investigated in ocular and cerebral vessels at autopsy. Methods. In 18 Malawian children who died from clinically defined CM, we studied the intensity of sequestration and the maturity of sequestered parasites in the retina, in nonretinal ocular tissues, and in the brain. Results. Five children with clinically defined CM during life had other causes of death identified at autopsy, no MR, and scanty intracerebral sequestration. Thirteen children had MR and died from CM. MR severity correlated with percentage of microvessels parasitized in the retina, brain, and nonretinal tissues with some neuroectodermal components (all P < .01). In moderate/severe MR cases (n = 8), vascular congestion was more intense (ρ = 0.841; P < .001), sequestered parasites were more mature, and the quantity of extraerythrocytic hemozoin was higher, compared with mild MR cases (n = 5). Conclusions. These data provide a histopathological basis for the known correlation between degrees of retinopathy and cerebral dysfunction in CM. In addition to being a valuable tool for clinical diagnosis, retinal observations give important information about neurovascular pathophysiology in pediatric CM.
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Affiliation(s)
- Valentina Barrera
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool
| | - Paul Stephenson Hiscott
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool
| | | | - Valerie Ann White
- Department of Pathology and Laboratory Medicine Department of Ophthalmology and Visual Science, University of British Columbia and Vancouver General Hospital, Canada
| | - Danny Arnold Milner
- Anatomic and Clinical Pathology, Brigham and Women's Hospital Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts
| | - Nicholas Alexander Venton Beare
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool St. Paul's Eye Unit, Royal Liverpool University Hospital, United Kingdom
| | - Ian James Callum MacCormick
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool Malawi-Liverpool-Wellcome Trust Clinical Research Programme
| | | | - Terrie Ellen Taylor
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre
| | - Malcolm Edward Molyneux
- Liverpool School of Tropical Medicine Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts
| | - Simon Peter Harding
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool
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90
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Micromagnetic resonance relaxometry for rapid label-free malaria diagnosis. Nat Med 2014; 20:1069-73. [PMID: 25173428 DOI: 10.1038/nm.3622] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 04/08/2014] [Indexed: 11/09/2022]
Abstract
We report a new technique for sensitive, quantitative and rapid detection of Plasmodium spp.-infected red blood cells (RBCs) by means of magnetic resonance relaxometry (MRR). During the intraerythrocytic cycle, malaria parasites metabolize large amounts of cellular hemoglobin and convert it into hemozoin crystallites. We exploit the relatively large paramagnetic susceptibility of these hemozoin particles, which induce substantial changes in the transverse relaxation rate of proton nuclear magnetic resonance of RBCs, to infer the 'parasite load' in blood. Using an inexpensive benchtop 0.5-Tesla MRR system, we show that with minimal sample preparatory steps and without any chemical or immunolabeling, a parasitemia level of fewer than ten parasites per microliter in a volume below 10 μl of whole blood is detected in a few minutes. We demonstrate this method both for cultured Plasmodium falciparum parasites and in vivo with Plasmodium berghei-infected mice.
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91
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Khaw LT, Ball HJ, Mitchell AJ, Grau GE, Stocker R, Golenser J, Hunt NH. Brain endothelial cells increase the proliferation of Plasmodium falciparum through production of soluble factors. Exp Parasitol 2014; 145:34-41. [PMID: 25045850 DOI: 10.1016/j.exppara.2014.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 05/06/2014] [Accepted: 07/08/2014] [Indexed: 01/01/2023]
Abstract
We here describe the novel finding that brain endothelial cells in vitro can stimulate the growth of Plasmodium falciparum through the production of low molecular weight growth factors. By using a conditioned medium approach, we show that the brain endothelial cells continued to release these factors over time. If this mirrors the in vivo situation, these growth factors potentially would provide an advantage, in terms of enhanced growth, for sequestered parasitised red blood cells in the brain microvasculature. We observed this phenomenon with brain endothelial cells from several sources as well as a second P. falciparum strain. The characteristics of the growth factors included: <3 kDa molecular weight, heat stable, and in part chloroform soluble. Future efforts should be directed at identifying these growth factors, since blocking their production or actions might be of benefit for reducing parasite load and, hence, malaria pathology.
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Affiliation(s)
- L T Khaw
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, Sydney Medical School, University of Sydney, NSW 2006, Australia; Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - H J Ball
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, Sydney Medical School, University of Sydney, NSW 2006, Australia
| | - A J Mitchell
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, Sydney Medical School, University of Sydney, NSW 2006, Australia; Immune Imaging Program, Centenary Institute, Sydney, NSW 2050, Australia
| | - G E Grau
- Vascular Immunology Unit, School of Medical Sciences and Bosch Institute, Sydney Medical School, University of Sydney, NSW 2006, Australia
| | - R Stocker
- Vascular Biology Division, Victor Chang Cardiac Research Institute, Lowy Packer Building, 405 Liverpool Street, Darlinghurst, NSW 2010, Australia
| | - J Golenser
- Department of Microbiology and Molecular Genetics, Kuvin Centre for the Study of Tropical and Infectious Diseases, Hebrew University of Jerusalem, Jerusalem, Israel
| | - N H Hunt
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, Sydney Medical School, University of Sydney, NSW 2006, Australia.
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Maude RJ, Kingston HWF, Joshi S, Mohanty S, Mishra SK, White NJ, Dondorp AM. Reversibility of retinal microvascular changes in severe falciparum malaria. Am J Trop Med Hyg 2014; 91:493-495. [PMID: 24935949 PMCID: PMC4155549 DOI: 10.4269/ajtmh.14-0116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Malarial retinopathy allows detailed study of central nervous system vascular pathology in living patients with severe malaria. An adult with cerebral malaria is described who had prominent retinal whitening with corresponding retinal microvascular obstruction, vessel dilatation, increased vascular tortuosity, and blood retinal barrier leakage with decreased visual acuity, all of which resolved on recovery. Additional study of these features and their potential role in elucidating the pathogenesis of cerebral malaria is warranted.
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Affiliation(s)
- Richard J. Maude
- *Address correspondence to Richard J. Maude, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Rajthevee, Bangkok 10400, Thailand. E-mail:
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93
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Delahunt C, Horning MP, Wilson BK, Proctor JL, Hegg MC. Limitations of haemozoin-based diagnosis of Plasmodium falciparum using dark-field microscopy. Malar J 2014; 13:147. [PMID: 24739286 PMCID: PMC4021049 DOI: 10.1186/1475-2875-13-147] [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: 02/16/2014] [Accepted: 04/12/2014] [Indexed: 11/13/2022] Open
Abstract
Background The haemozoin crystal continues to be investigated extensively for its potential as a biomarker for malaria diagnostics. In order for haemozoin to be a valuable biomarker, it must be present in detectable quantities in the peripheral blood and distinguishable from false positives. Here, dark-field microscopy coupled with sophisticated image processing algorithms is used to characterize the abundance of detectable haemozoin within infected erythrocytes from field samples in order to determine the window of detection in peripheral blood. Methods Thin smears from Plasmodium falciparum-infected and uninfected patients were imaged in both dark field (DF) unstained and bright field (BF) Giemsa-stained modes. The images were co-registered such that each parasite had thumbnails in both BF and DF modes, providing an accurate map between parasites and DF objects. This map was used to find the abundance of haemozoin as a function of parasite stage through careful parasite staging and correlation with DF objects. An automated image-processing and classification algorithm classified the bright spots in the DF images as either haemozoin or non-haemozoin objects. Results The algorithm distinguishes haemozoin from non-haemozoin objects in DF images with an object-level sensitivity of 95% and specificity of 97%. Ring stages older than about 6 hours begin to show detectable haemozoin, and rings between 10–16 hours reliably contain detectable haemozoin. However, DF microscopy coupled with the image-processing algorithm detect no haemozoin in rings younger than six hours. Discussion Although this method demonstrates the most sensitive detection of haemozoin in field samples reported to date, it does not detect haemozoin in ring-stage parasites younger than six hours. Thus, haemozoin is a poor biomarker for field samples primarily composed of young ring-stage parasites because the crystal is not present in detectable quantities by the methods described here. Based on these results, the implications for patient-level diagnosis and recommendations for future work are discussed.
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94
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N'Dilimabaka N, Taoufiq Z, Zougbédé S, Bonnefoy S, Lorthiois A, Couraud PO, Rebollo A, Snounou G, Mazier D, Moreno Sabater A. P. falciparum isolate-specific distinct patterns of induced apoptosis in pulmonary and brain endothelial cells. PLoS One 2014; 9:e90692. [PMID: 24686750 PMCID: PMC3970966 DOI: 10.1371/journal.pone.0090692] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Accepted: 02/04/2014] [Indexed: 11/18/2022] Open
Abstract
The factors implicated in the transition from uncomplicated to severe clinical malaria such as pulmonary oedema and cerebral malaria remain unclear. It is known that alterations in vascular integrity due to endothelial cell (EC) activation and death occur during severe malaria. In this study, we assessed the ability of different P. falciparum clinical isolates to induce apoptosis in ECs derived from human lung and brain. We observed that induction of EC apoptosis was sensitive to the environmental pH and required direct contact between the parasite and the cell, though it was not correlated to the ability of the parasite to cytoadhere. Moreover, the extent of induced apoptosis in the two EC types varied with the isolate. Analysis of parasite genes transcript led us to propose that the activation of different pathways, such as Plasmodium apoptosis-linked pathogenicity factors (PALPF), PALPF-2, PALPF-5 and PF11_0521, could be implied in EC death. These observations provide an experimental framework to decipher the molecular mechanism implicated in the genesis of severe malaria.
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Affiliation(s)
- Nadine N'Dilimabaka
- Université Pierre et Marie Curie-Paris 6, UMRS 945, Paris, France
- Institut National de la Santé et de la Recherche Médicale, UMRS 945, Paris, France
| | - Zacharie Taoufiq
- Université Pierre et Marie Curie-Paris 6, UMRS 945, Paris, France
- Institut National de la Santé et de la Recherche Médicale, UMRS 945, Paris, France
| | - Sergine Zougbédé
- Université Pierre et Marie Curie-Paris 6, UMRS 945, Paris, France
- Institut National de la Santé et de la Recherche Médicale, UMRS 945, Paris, France
| | - Serge Bonnefoy
- Institut Pasteur, Unité d'Immunologie Moléculaire des Parasites, CNRS URA 2581, Paris, France
| | - Audrey Lorthiois
- Université Pierre et Marie Curie-Paris 6, UMRS 945, Paris, France
- Institut National de la Santé et de la Recherche Médicale, UMRS 945, Paris, France
| | - Pierre Oliver Couraud
- Institut National de la Santé et de la Recherche Médicale, U1016, Institut Cochin, Paris, France
- CNRS, UMR8104, Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Angelita Rebollo
- Université Pierre et Marie Curie-Paris 6, UMRS 945, Paris, France
- Institut National de la Santé et de la Recherche Médicale, UMRS 945, Paris, France
| | - Georges Snounou
- Université Pierre et Marie Curie-Paris 6, UMRS 945, Paris, France
- Institut National de la Santé et de la Recherche Médicale, UMRS 945, Paris, France
| | - Dominique Mazier
- Université Pierre et Marie Curie-Paris 6, UMRS 945, Paris, France
- Institut National de la Santé et de la Recherche Médicale, UMRS 945, Paris, France
- Laboratoire de Parasitologie-Mycologie, AP-HP, Hôpital Pitié Salpêtrière, Paris, France
| | - Alicia Moreno Sabater
- Université Pierre et Marie Curie-Paris 6, UMRS 945, Paris, France
- Institut National de la Santé et de la Recherche Médicale, UMRS 945, Paris, France
- * E-mail:
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95
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Abdi AI, Fegan G, Muthui M, Kiragu E, Musyoki JN, Opiyo M, Marsh K, Warimwe GM, Bull PC. Plasmodium falciparum antigenic variation: relationships between widespread endothelial activation, parasite PfEMP1 expression and severe malaria. BMC Infect Dis 2014; 14:170. [PMID: 24674301 PMCID: PMC3986854 DOI: 10.1186/1471-2334-14-170] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 03/19/2014] [Indexed: 12/01/2022] Open
Abstract
Background Plasmodium falciparum erythrocyte membrane protein 1(PfEMP1) is a family of variant surface antigens (VSA) that mediate the adhesion of parasite infected erythrocytes to capillary endothelial cells within host tissues. Opinion is divided over the role of PfEMP1 in the widespread endothelial activation associated with severe malaria. In a previous study we found evidence for differential associations between defined VSA subsets and specific syndromes of severe malaria: group A-like PfEMP1 expression and the “rosetting” phenotype were associated with impaired consciousness and respiratory distress, respectively. This study explores the involvement of widespread endothelial activation in these associations. Methods We used plasma angiopoietin-2 as a marker of widespread endothelial activation. Using logistic regression analysis, we explored the relationships between plasma angiopoietin-2 levels, parasite VSA expression and the two syndromes of severe malaria, impaired consciousness and respiratory distress. Results Plasma angiopoietin-2 was associated with both syndromes. The rosetting phenotype did not show an independent association with respiratory distress when adjusted for angiopoietin-2, consistent with a single pathogenic mechanism involving widespread endothelial activation. In contrast, group A-like PfEMP1 expression and angiopoietin-2 maintained independent associations with impaired consciousness when adjusted for each other. Conclusion The results are consistent with multiple pathogenic mechanisms leading to severe malaria and heterogeneity in the pathophysiology of impaired consciousness. The observed association between group A-like PfEMP1 and impaired consciousness does not appear to involve widespread endothelial activation.
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Affiliation(s)
- Abdirahman I Abdi
- KEMRI-Wellcome Trust Research Programme, P,O, Box 230-80108, Kilifi, Kenya.
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96
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Kunwittaya S, Treeratanapiboon L, Srisarin A, Isarankura-Na-Ayudhya C, Prachayasittikul V. In vitro study of parasite elimination and endothelial protection by curcumin: adjunctive therapy for cerebral malaria. EXCLI JOURNAL 2014; 13:287-99. [PMID: 26417261 PMCID: PMC4464332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 02/19/2014] [Indexed: 10/25/2022]
Abstract
Plasmodium falciparum infection can abruptly progress to severe malaria and cerebral malaria. Despite the current efficiency of antimalarial drugs in killing parasites, no specific effective treatment has been found for cerebral malaria. Thus, a new strategy targeting both parasite elimination and endothelial cell protection is urgently needed in this field. In this study, we determined whether curcumin, which has blood-brain permeability, antioxidative activity and/or immunomodulation property, provided a potential effect on both parasite elimination and endothelial protection. Murine brain microvascular endothelial cells (bEnd.3; ATCC) were cocultured with Plasmodium falciparum-infected red blood cells (Pf-IRBC), peripheral blood mononuclear cell (PBMC) and platelets. Apoptosis of endothelial cells was demonstrated by annexin V staining. Interestingly, curcumin exhibited high efficiency of antimalarial activity (IC50 ~10 µM) and decreased bEnd.3 apoptosis down to 60.0 % and 79.6 % upon pre-treatment and co-treatment, respectively, with Pf-IRBC, platelets and PBMC. Our findings open up a high feasibility of applying curcumin as a potential adjunctive compound for cerebral malaria treatment in the future.
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Affiliation(s)
- Sarun Kunwittaya
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand
| | - Lertyot Treeratanapiboon
- Center for Innovation Development and Technology Transfer, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand,Department of Parasitology and Community Health, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand
| | - Apapan Srisarin
- Department of Clinical Microscopy, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand
| | - Chartchalerm Isarankura-Na-Ayudhya
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand,*To whom correspondence should be addressed: Virapong Prachayasittikul, Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand
| | - Virapong Prachayasittikul
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand,*To whom correspondence should be addressed: Virapong Prachayasittikul, Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok 10700, Thailand
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97
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Abstract
In this issue of Blood, Aird et al review recent findings that suggest the endothelial protein C receptor (EPCR), known for its pivotal role in mediating cytoprotection against coagulopathy, proinflammatory cytokines, and vascular permeability, may serve as a receptor for Plasmodium falciparum-infected red blood cells (IRBCs) in the brain. In the process, coagulation is allowed to proceed unchecked and contributes to the pathogenesis of cerebral malaria.
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98
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MacCormick IJC, Beare NAV, Taylor TE, Barrera V, White VA, Hiscott P, Molyneux ME, Dhillon B, Harding SP. Cerebral malaria in children: using the retina to study the brain. ACTA ACUST UNITED AC 2014; 137:2119-42. [PMID: 24578549 PMCID: PMC4107732 DOI: 10.1093/brain/awu001] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cerebral malaria is a dangerous complication of Plasmodium falciparum infection, which takes a devastating toll on children in sub-Saharan Africa. Although autopsy studies have improved understanding of cerebral malaria pathology in fatal cases, information about in vivo neurovascular pathogenesis is scarce because brain tissue is inaccessible in life. Surrogate markers may provide insight into pathogenesis and thereby facilitate clinical studies with the ultimate aim of improving the treatment and prognosis of cerebral malaria. The retina is an attractive source of potential surrogate markers for paediatric cerebral malaria because, in this condition, the retina seems to sustain microvascular damage similar to that of the brain. In paediatric cerebral malaria a combination of retinal signs correlates, in fatal cases, with the severity of brain pathology, and has diagnostic and prognostic significance. Unlike the brain, the retina is accessible to high-resolution, non-invasive imaging. We aimed to determine the extent to which paediatric malarial retinopathy reflects cerebrovascular damage by reviewing the literature to compare retinal and cerebral manifestations of retinopathy-positive paediatric cerebral malaria. We then compared retina and brain in terms of anatomical and physiological features that could help to account for similarities and differences in vascular pathology. These comparisons address the question of whether it is biologically plausible to draw conclusions about unseen cerebral vascular pathogenesis from the visible retinal vasculature in retinopathy-positive paediatric cerebral malaria. Our work addresses an important cause of death and neurodisability in sub-Saharan Africa. We critically appraise evidence for associations between retina and brain neurovasculature in health and disease, and in the process we develop new hypotheses about why these vascular beds are susceptible to sequestration of parasitized erythrocytes.
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Affiliation(s)
- Ian J C MacCormick
- 1 Malawi-Liverpool-Wellcome Trust Clinical Research Programme, PO Box 30096, Chichiri, Blantyre 3, Malawi2 University of Liverpool, Department of Eye and Vision Science, Faculty of Health & Life Sciences, University of Liverpool Room 356, 4th Floor, UCD Building, Daulby Street, Liverpool L69 3GA, UK
| | - Nicholas A V Beare
- 2 University of Liverpool, Department of Eye and Vision Science, Faculty of Health & Life Sciences, University of Liverpool Room 356, 4th Floor, UCD Building, Daulby Street, Liverpool L69 3GA, UK3 Royal Liverpool University Hospital, St. Paul's Eye Unit, Prescot St, Liverpool, Merseyside L7 8XP, UK
| | - Terrie E Taylor
- 5 Blantyre Malaria Project, Blantyre, Malawi6 Michigan State University, Department of Osteopathic Medical Specialities, West Fee Hall, 909 Fee Road, Room B305, East Lansing, MI 48824, USA
| | - Valentina Barrera
- 2 University of Liverpool, Department of Eye and Vision Science, Faculty of Health & Life Sciences, University of Liverpool Room 356, 4th Floor, UCD Building, Daulby Street, Liverpool L69 3GA, UK
| | - Valerie A White
- 7 Vancouver General Hospital, Department of Pathology and Laboratory Medicine, Vancouver, B.C. V5Z1M9, Canada
| | - Paul Hiscott
- 2 University of Liverpool, Department of Eye and Vision Science, Faculty of Health & Life Sciences, University of Liverpool Room 356, 4th Floor, UCD Building, Daulby Street, Liverpool L69 3GA, UK
| | - Malcolm E Molyneux
- 1 Malawi-Liverpool-Wellcome Trust Clinical Research Programme, PO Box 30096, Chichiri, Blantyre 3, Malawi4 University of Malawi College of Medicine, College of Medicine, P/Bag 360 Chichiri, Blantyre 3 Malawi8 Liverpool School of Tropical Medicine, Liverpool School of Tropical Medicine, Pembroke Place , Liverpool, L3 5QA , UK
| | - Baljean Dhillon
- 9 University of Edinburgh, Department of Ophthalmology, Edinburgh, UK10 Princess Alexandra Eye Pavilion, Edinburgh, UK
| | - Simon P Harding
- 2 University of Liverpool, Department of Eye and Vision Science, Faculty of Health & Life Sciences, University of Liverpool Room 356, 4th Floor, UCD Building, Daulby Street, Liverpool L69 3GA, UK3 Royal Liverpool University Hospital, St. Paul's Eye Unit, Prescot St, Liverpool, Merseyside L7 8XP, UK
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99
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Abstract
Although global morbidity and mortality have decreased substantially, malaria, a parasite infection of red blood cells, still kills roughly 2000 people per day, most of whom are children in Africa. Two factors largely account for these decreases; increased deployment of insecticide-treated bednets and increased availability of highly effective artemisinin combination treatments. In large trials, parenteral artesunate (an artemisinin derivative) reduced severe malaria mortality by 22·5% in Africa and 34·7% in Asia compared with quinine, whereas adjunctive interventions have been uniformly unsuccessful. Rapid tests have been an important addition to microscopy for malaria diagnosis. Chemopreventive strategies have been increasingly deployed in Africa, notably intermittent sulfadoxine-pyrimethamine treatment in pregnancy, and monthly amodiaquine-sulfadoxine-pyrimethamine during the rainy season months in children aged between 3 months and 5 years across the sub-Sahel. Enthusiasm for malaria elimination has resurfaced. This ambitious but laudable goal faces many challenges, including the worldwide economic downturn, difficulties in elimination of vivax malaria, development of pyrethroid resistance in some anopheline mosquitoes, and the emergence of artemisinin resistance in Plasmodium falciparum in southeast Asia. We review the epidemiology, clinical features, pathology, prevention, and treatment of malaria.
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Affiliation(s)
- Nicholas J White
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford, UK.
| | | | - Tran Tinh Hien
- Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam
| | - M Abul Faiz
- Department of Medicine, Dev Care Foundation, Dhaka, Bangladesh
| | | | - Arjen M Dondorp
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford, UK
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100
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Claser C, Malleret B, Peng K, Bakocevic N, Gun SY, Russell B, Ng LG, Rénia L. Rodent Plasmodium-infected red blood cells: Imaging their fates and interactions within their hosts. Parasitol Int 2014; 63:187-94. [DOI: 10.1016/j.parint.2013.07.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 06/30/2013] [Accepted: 07/15/2013] [Indexed: 10/26/2022]
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