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Abstract
In the mosquito-human life cycle, the six species of malaria parasites infecting humans (Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale wallickeri, Plasmodium ovale curtisi, Plasmodium malariae, and Plasmodium knowlesi) undergo 10 or more morphological states, replicate from single to 10,000+ cells, and vary in total population from one to many more than 106 organisms. In the human host, only a small number of these morphological stages lead to clinical disease and the vast majority of all malaria-infected patients in the world produce few (if any) symptoms in the human. Human clinical disease (e.g., fever, anemia, coma) is the result of the parasite preprogrammed biology in concert with the human pathophysiological response. Caveats and corollaries that add variation to this host-parasite interaction include parasite genetic diversity of key proteins, coinfections, comorbidities, delays in treatment, human polymorphisms, and environmental determinants.
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Affiliation(s)
- Danny A Milner
- Harvard T.H. Chan School of Public Health, American Society for Clinical Pathology, Center for Global Health, Chicago, Illinois 60603
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52
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Leitgeb AM, Charunwatthana P, Rueangveerayut R, Uthaisin C, Silamut K, Chotivanich K, Sila P, Moll K, Lee SJ, Lindgren M, Holmer E, Färnert A, Kiwuwa MS, Kristensen J, Herder C, Tarning J, Wahlgren M, Dondorp AM. Inhibition of merozoite invasion and transient de-sequestration by sevuparin in humans with Plasmodium falciparum malaria. PLoS One 2017; 12:e0188754. [PMID: 29244851 PMCID: PMC5731734 DOI: 10.1371/journal.pone.0188754] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 11/03/2017] [Indexed: 11/19/2022] Open
Abstract
SEVERE MALARIA Even with the best available treatment, the mortality from severe Plasmodium falciparum malaria remains high. Typical features at death are high parasite loads and obstructed micro- vasculature. Infected erythrocytes (IE) containing mature parasites bind to the host receptor heparan sulfate, which is also an important receptor for merozoite invasion. To block merozoite invasion has not previously been proposed as an adjunctive therapeutic approach but it may preclude the early expansion of an infection that else leads to exacerbated sequestration and death. SEVUPARIN IN PHASE I STUDY The drug sevuparin was developed from heparin because heparan sulfate and heparin are nearly identical, so the rationale was that sevuparin would act as a decoy receptor during malaria infection. A phase I study was performed in healthy male volunteers and sevuparin was found safe and well tolerated. SEVUPARIN IN PHASE I/II CLINICAL STUDY A phase I/II clinical study was performed in which sevuparin was administered via short intravenous infusions to malaria patients with uncomplicated malaria who were also receiving atovaquone/proguanil treatment. This was a Phase I/II, randomized, open label, active control, parallel assignment study. Sevuparin was safe and well tolerated in the malaria patients. The mean relative numbers of ring-stage IEs decreased after a single sevuparin infusion and mature parasite IEs appeared transiently in the circulation. The effects observed on numbers of merozoites and throphozoites in the circulation, were detected already one hour after the first sevuparin injection. Here we report the development of a candidate drug named sevuparin that both blocks merozoite invasion and transiently de-sequesters IE in humans with P. falciparum malaria. TRIAL REGISTRATION ClinicalTrials.gov NCT01442168.
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Affiliation(s)
| | | | | | | | - Kamolrat Silamut
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | | | | | - Kirsten Moll
- Department of Microbiology, Tumor- and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Sue J. Lee
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | | | - Anna Färnert
- Department of Infectious Diseases, Karolinska University Hospital and Department Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Mpungu S. Kiwuwa
- Department of Pediatrics, School of Medicine, Makerere University College of Health Sciences, and Department of Biochemistry, School of Biomedical Sciences, Makerere University College of Health Sciences, Kampala, Uganda
| | | | | | - Joel Tarning
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mats Wahlgren
- Department of Microbiology, Tumor- and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Arjen M. Dondorp
- Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
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Fitri LE, Rosmarwati E, Rizky Y, Budiarti N, Samsu N, Mintaroem K. Strong renal expression of heat shock protein 70, high mobility group box 1, inducible nitric oxide synthase, and nitrotyrosine in mice model of severe malaria. Rev Soc Bras Med Trop 2017; 50:489-498. [PMID: 28954070 DOI: 10.1590/0037-8682-0049-2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 08/10/2017] [Indexed: 02/05/2023] Open
Abstract
INTRODUCTION Renal damage is a consequence of severe malaria, and is generally caused by sequestration of Plasmodium falciparum -infected erythrocytes in the renal microcirculation, which leads to obstruction, hypoxia, and ischemia. This triggers high mobility group box 1 (HMGB1) to send a danger signal through toll-like receptors 2 and 4. This signal up-regulates inducible nitric oxide (iNOS) and nitrotyrosine to re-perfuse the tissue, and also increases heat shock protein 70 (HSP70) expression. As no study has examined the involvement of intracellular secondary molecules in this setting, the present study compared the renal expressions of HSP70, HMGB1, iNOS, and nitrotyrosine between mice suffered from severe malaria and normal mice. METHODS C57BL/6 mice were divided into an infected group (intraperitoneal injection of 10 6 P. berghei ANKA) and a non-infected group. Renal damage was evaluated using hematoxylin eosin staining, and immunohistochemistry was used to evaluate the expressions of HSP70, HMGB1, iNOS, and nitrotyrosine. RESULTS Significant inter-group differences were observed in the renal expressions of HSP70, HMGB1, and iNOS (p=0.000, Mann-Whitney test), as well as nitrotyrosine (p=0.000, independent t test). The expressions of HSP70 and HMGB1 were strongly correlated (p=0.000, R=1.000). No correlations were observed between iNOS and HMGB, HMGB1 and nitrotyrosine, HSP70 and nitrotyrosine, or iNOS and nitrotyrosine. CONCLUSIONS It appears that HMGB1, HSP70, iNOS, and nitrotyrosine play roles in the renal damage that is observed in mice with severe malaria. Only HSP70 expression is strongly correlated with the expression of HMGB1.
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Affiliation(s)
- Loeki Enggar Fitri
- Department of Parasitology, Faculty of Medicine, Universitas Brawijaya, Malang, Indonesia
| | - Ervina Rosmarwati
- Master Program in Biomedical Sciences, Faculty of Medicine, Universitas Brawijaya, Malang, Indonesia
| | - Yesita Rizky
- Master Program in Biomedical Sciences, Faculty of Medicine, Universitas Brawijaya, Malang, Indonesia
| | - Niniek Budiarti
- Tropical Medicine Division, Internal Medicine Department, Faculty of Medicine, Universitas Brawijaya, dr. Saiful Anwar Public Hospital, Malang, Indonesia
| | - Nur Samsu
- Renal and Hypertension Division, Internal Medicine Department, Faculty of Medicine, Universitas Brawijaya, dr Saiful Anwar Public Hospital, Malang, Indonesia
| | - Karyono Mintaroem
- Department of Pathology Anatomy, Faculty of Medicine, Universitas Brawijaya, Malang, Indonesia
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54
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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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55
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Dunst J, Kamena F, Matuschewski K. Cytokines and Chemokines in Cerebral Malaria Pathogenesis. Front Cell Infect Microbiol 2017; 7:324. [PMID: 28775960 PMCID: PMC5517394 DOI: 10.3389/fcimb.2017.00324] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 07/03/2017] [Indexed: 12/18/2022] Open
Abstract
Cerebral malaria is among the major causes of malaria-associated mortality and effective adjunctive therapeutic strategies are currently lacking. Central pathophysiological processes involved in the development of cerebral malaria include an imbalance of pro- and anti-inflammatory responses to Plasmodium infection, endothelial cell activation, and loss of blood-brain barrier integrity. However, the sequence of events, which initiates these pathophysiological processes as well as the contribution of their complex interplay to the development of cerebral malaria remain incompletely understood. Several cytokines and chemokines have repeatedly been associated with cerebral malaria severity. Increased levels of these inflammatory mediators could account for the sequestration of leukocytes in the cerebral microvasculature present during cerebral malaria, thereby contributing to an amplification of local inflammation and promoting cerebral malaria pathogenesis. Herein, we highlight the current knowledge on the contribution of cytokines and chemokines to the pathogenesis of cerebral malaria with particular emphasis on their roles in endothelial activation and leukocyte recruitment, as well as their implication in the progression to blood-brain barrier permeability and neuroinflammation, in both human cerebral malaria and in the murine experimental cerebral malaria model. A better molecular understanding of these processes could provide the basis for evidence-based development of adjunct therapies and the definition of diagnostic markers of disease progression.
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Affiliation(s)
- Josefine Dunst
- Parasitology Unit, Max Planck Institute for Infection BiologyBerlin, Germany.,Institute of Chemistry and Biochemistry, Free UniversityBerlin, Germany.,Molecular Parasitology, Institute of Biology, Humboldt UniversityBerlin, Germany
| | - Faustin Kamena
- Parasitology Unit, Max Planck Institute for Infection BiologyBerlin, Germany.,Institute of Chemistry and Biochemistry, Free UniversityBerlin, Germany.,Molecular Parasitology, Institute of Biology, Humboldt UniversityBerlin, Germany
| | - Kai Matuschewski
- Parasitology Unit, Max Planck Institute for Infection BiologyBerlin, Germany.,Institute of Chemistry and Biochemistry, Free UniversityBerlin, Germany
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56
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Magnetic Resonance Imaging of Cerebral Malaria Patients Reveals Distinct Pathogenetic Processes in Different Parts of the Brain. mSphere 2017; 2:mSphere00193-17. [PMID: 28596990 PMCID: PMC5463026 DOI: 10.1128/msphere.00193-17] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 05/09/2017] [Indexed: 12/02/2022] Open
Abstract
The pathophysiology and molecular mechanisms underlying cerebral malaria (CM) are still poorly understood. Recent neuroimaging studies demonstrated that brain swelling is a common feature in CM and a major contributor to death in pediatric patients. Consequently, determining the precise mechanisms responsible for this swelling could open new adjunct therapeutic avenues in CM patients. Using an MRI scanner with a higher resolution than the ones used in previous reports, we identified two distinct origins of brain swelling in both adult and pediatric patients from India, occurring in distinct parts of the brain. Our results support the hypothesis that both endothelial dysfunction and microvascular obstruction by Plasmodium falciparum-infected erythrocytes make independent contributions to the pathogenesis of CM, providing opportunities for novel therapeutic interventions. The mechanisms underlying the rapidly reversible brain swelling described in patients with cerebral malaria (CM) are unknown. Using a 1.5-Tesla (T) magnetic resonance imaging (MRI) scanner, we undertook an observational study in Rourkela, India, of 11 Indian patients hospitalized with CM and increased brain volume. Among the 11 cases, there were 5 adults and 6 children. All patients had reduced consciousness and various degrees of cortical swelling at baseline. The latter was predominately posterior in distribution. The findings on diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps were consistent with vasogenic edema in all cases. Reversibility after 48 to 72 h was observed in >90% of cases. DWI/ADC mismatch suggested the additional presence of cytotoxic edema in the basal nuclei of 5 patients; all of these had perfusion parameters consistent with vascular engorgement and not with ischemic infarcts. Our results suggest that an impairment of the blood-brain barrier is responsible for the brain swelling in CM. In 5 cases, vasogenic edema occurred in conjunction with changes in the basal nuclei consistent with venous congestion, likely to be caused by the sequestration of Plasmodium falciparum-infected erythrocytes. While both mechanisms have been individually postulated to play an important role in the development of CM, this is the first demonstration of their concurrent involvement in different parts of the brain. The clinical and radiological characteristics observed in the majority of our patients are consistent with posterior reversible encephalopathy syndrome (PRES), and we show for the first time a high frequency of PRES in the context of CM. IMPORTANCE The pathophysiology and molecular mechanisms underlying cerebral malaria (CM) are still poorly understood. Recent neuroimaging studies demonstrated that brain swelling is a common feature in CM and a major contributor to death in pediatric patients. Consequently, determining the precise mechanisms responsible for this swelling could open new adjunct therapeutic avenues in CM patients. Using an MRI scanner with a higher resolution than the ones used in previous reports, we identified two distinct origins of brain swelling in both adult and pediatric patients from India, occurring in distinct parts of the brain. Our results support the hypothesis that both endothelial dysfunction and microvascular obstruction by Plasmodium falciparum-infected erythrocytes make independent contributions to the pathogenesis of CM, providing opportunities for novel therapeutic interventions.
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57
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Hempel C, Wang CW, Kurtzhals JAL, Staalsø T. Binding of Plasmodium falciparum to CD36 can be shielded by the glycocalyx. Malar J 2017; 16:193. [PMID: 28486940 PMCID: PMC5424350 DOI: 10.1186/s12936-017-1844-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 04/27/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Plasmodium falciparum-infected erythrocytes sequester in the microcirculation due to interaction between surface-expressed parasite proteins and endothelial receptors. Endothelial cells are covered in a carbohydrate-rich glycocalyx that shields against undesired leukocyte adhesion. It was investigated if the cellular glycocalyx affects the binding of P. falciparum-infected erythrocytes to CD36 in vitro. METHODS Glycocalyx growth was followed in vitro by using azido sugars and cationized ferritin detecting O-glycoproteins and negatively charged proteoglycans, respectively. P. falciparum (clone FCR3/IT) was selected on Chinese hamster ovary (CHO) cells transfected with human CD36. Cytoadhesion to CHO CD36 at 1-4 days after seeding was quantified by using a static binding assay. RESULTS The glycocalyx thickness of CHO cells increased during 4 days in culture as assessed by metabolic labelling of glycans with azido sugars and with electron microscopy studying the binding of cationized ferritin to cell surfaces. The functional importance of this process was addressed in binding assays by using CHO cells transfected with CD36. In parallel with the maturation of the glycocalyx, antibody-binding to CD36 was inhibited, despite stable expression of CD36. P. falciparum selected for CD36-binding recognized CD36 on CHO cells on the first day in culture, but the binding was lost after 2-4 days. CONCLUSION The endothelial glycocalyx affects parasite cytoadhesion in vitro, an effect that has previously been ignored. The previously reported loss of glycocalyx during experimental malaria may play an important role in the pathogenesis of malaria complications by allowing the close interaction between infected erythrocytes and endothelial receptors.
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Affiliation(s)
- Casper Hempel
- Department of Clinical Microbiology, Centre for Medical Parasitology, Copenhagen University Hospital, Copenhagen, Denmark. .,Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark. .,Department of Micro- and Nanotechnology, Technical University of Denmark, Kongens Lyngby, Denmark.
| | - Christian William Wang
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark
| | - Jørgen Anders Lindholm Kurtzhals
- Department of Clinical Microbiology, Centre for Medical Parasitology, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Trine Staalsø
- Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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58
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Villaverde C, Namazzi R, Shabani E, Opoka RO, John CC. Clinical Comparison of Retinopathy-Positive and Retinopathy-Negative Cerebral Malaria. Am J Trop Med Hyg 2017; 96:1176-1184. [PMID: 28138045 DOI: 10.4269/ajtmh.16-0315] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
AbstractCerebral malaria (CM) is a severe and often lethal complication of falciparum malaria. A classic malaria retinopathy is seen in some (retinopathy-positive [RP]) children but not others (retinopathy-negative [RN]), and is associated with increased parasite sequestration. It is unclear whether RN CM is a severe nonmalarial illness with incidental parasitemia or a less severe form of the same malarial illness as RP CM. Understanding the clinical differences between RP and RN CM may help shed light on the pathophysiology of malarial retinopathy. We compared clinical history, physical examination, laboratory findings, and outcomes of RP (N = 167) and RN (N = 87) children admitted to Mulago Hospital, Kampala, Uganda. Compared with RN children, RP children presented with a longer history of illness, as well as physical examination and laboratory findings indicative of more severe disease and organ damage. The hospital course of RP children was complicated by longer coma duration and a greater transfusion burden than RN children. Mortality did not differ significantly between RP and RN children (14.4% versus 8.0%, P = 0.14). Further, severity of retinal hemorrhage correlated with the majority of variables that differed between RP and RN children. The data suggest that RP and RN CM may reflect the spectrum of illness in CM, and that RN CM could be an earlier, less severe form of disease.
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Affiliation(s)
- Chandler Villaverde
- The Warren Alpert Medical School, Brown University, Providence, Rhode Island
| | - Ruth Namazzi
- Department of Paediatrics and Child Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Estela Shabani
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota.,Department of Pediatrics, Indiana University, Indianapolis, Indiana
| | - Robert O Opoka
- Department of Paediatrics and Child Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Chandy C John
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota.,Department of Pediatrics, Indiana University, Indianapolis, Indiana
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59
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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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Bernabeu M, Smith JD. EPCR and Malaria Severity: The Center of a Perfect Storm. Trends Parasitol 2016; 33:295-308. [PMID: 27939609 DOI: 10.1016/j.pt.2016.11.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 11/07/2016] [Accepted: 11/10/2016] [Indexed: 12/20/2022]
Abstract
Severe malaria due to Plasmodium falciparum infection causes nearly half a million deaths per year. The different symptomatology and disease manifestations among patients have hampered understanding of severe malaria pathology and complicated efforts to develop targeted disease interventions. Infected erythrocyte sequestration in the microvasculature plays a critical role in the development of severe disease, and there is increasing evidence that cytoadherent parasites interact with host factors to enhance the damage caused by the parasite. The recent discovery that parasite binding to endothelial protein C receptor (EPCR) is associated with severe disease has suggested new mechanisms of pathology and provided new avenues for severe malaria adjunctive therapy research.
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Affiliation(s)
- Maria Bernabeu
- Center for Infectious Disease Research, Seattle, WA 98109, USA
| | - Joseph D Smith
- Center for Infectious Disease Research, Seattle, WA 98109, USA; Department of Global Health, University of Washington, Seattle, WA 98195, USA.
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61
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Fougère A, Jackson AP, Paraskevi Bechtsi D, Braks JAM, Annoura T, Fonager J, Spaccapelo R, Ramesar J, Chevalley-Maurel S, Klop O, van der Laan AMA, Tanke HJ, Kocken CHM, Pasini EM, Khan SM, Böhme U, van Ooij C, Otto TD, Janse CJ, Franke-Fayard B. Variant Exported Blood-Stage Proteins Encoded by Plasmodium Multigene Families Are Expressed in Liver Stages Where They Are Exported into the Parasitophorous Vacuole. PLoS Pathog 2016; 12:e1005917. [PMID: 27851824 PMCID: PMC5113031 DOI: 10.1371/journal.ppat.1005917] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 09/06/2016] [Indexed: 01/05/2023] Open
Abstract
Many variant proteins encoded by Plasmodium-specific multigene families are exported into red blood cells (RBC). P. falciparum-specific variant proteins encoded by the var, stevor and rifin multigene families are exported onto the surface of infected red blood cells (iRBC) and mediate interactions between iRBC and host cells resulting in tissue sequestration and rosetting. However, the precise function of most other Plasmodium multigene families encoding exported proteins is unknown. To understand the role of RBC-exported proteins of rodent malaria parasites (RMP) we analysed the expression and cellular location by fluorescent-tagging of members of the pir, fam-a and fam-b multigene families. Furthermore, we performed phylogenetic analyses of the fam-a and fam-b multigene families, which indicate that both families have a history of functional differentiation unique to RMP. We demonstrate for all three families that expression of family members in iRBC is not mutually exclusive. Most tagged proteins were transported into the iRBC cytoplasm but not onto the iRBC plasma membrane, indicating that they are unlikely to play a direct role in iRBC-host cell interactions. Unexpectedly, most family members are also expressed during the liver stage, where they are transported into the parasitophorous vacuole. This suggests that these protein families promote parasite development in both the liver and blood, either by supporting parasite development within hepatocytes and erythrocytes and/or by manipulating the host immune response. Indeed, in the case of Fam-A, which have a steroidogenic acute regulatory-related lipid transfer (START) domain, we found that several family members can transfer phosphatidylcholine in vitro. These observations indicate that these proteins may transport (host) phosphatidylcholine for membrane synthesis. This is the first demonstration of a biological function of any exported variant protein family of rodent malaria parasites. Malaria-parasites invade and multiply in hepatocytes and erythrocytes. The human parasite P. falciparum transports proteins encoded by multigene families onto the surface of erythrocytes, mediating interactions between infected red blood cells (iRBCs) and other host-cells and are thought to play a key role in parasite survival during blood-stage development. The function of other exported Plasmodium protein families remains largely unknown. We provide novel insights into expression and cellular location of proteins encoded by three large multigene families of rodent malaria parasites (Fam-a, Fam-b and PIR). Multiple members of the same family are expressed in a single iRBC, unlike P. falciparum PfEMP1 proteins where individual iRBCs express only a single member. Most proteins we examined are located in the RBC cytoplasm and are not transported onto the iRBC surface membrane, indicating that these proteins are unlikely to mediate interactions between iRBCs and host-cells. Unexpectedly, liver stages also express many of these proteins, where they locate to the vacuole surrounding the parasite inside the hepatocyte. In support of a role of these proteins for parasite growth within their host cells we provide evidence that Fam-A proteins have a role in uptake and transport of (host) phosphatidylcholine for parasite-membrane synthesis.
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Affiliation(s)
- Aurélie Fougère
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
- Department of Experimental Medicine, University of Perugia, Italy
| | - Andrew P. Jackson
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UnitedKingdom
| | | | - Joanna A. M. Braks
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Takeshi Annoura
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
- Department of Department of Parasitology, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Jannik Fonager
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
- Department of Microbiological Diagnostics and Virology, Statens Serum Institute, Copenhagen, Denmark
| | | | - Jai Ramesar
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Séverine Chevalley-Maurel
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Onny Klop
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
- Biomedical Primate Research Centre (BPRC), Rijswijk, The Netherlands
| | | | - Hans J. Tanke
- Department of Molecular Cell Biology, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | | | - Erica M. Pasini
- Biomedical Primate Research Centre (BPRC), Rijswijk, The Netherlands
| | - Shahid M. Khan
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Ulrike Böhme
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, UnitedKingdom
| | - Christiaan van Ooij
- The Francis Crick Institute, Mill Hill Laboratory, Mill Hill, London, UnitedKingdom
| | - Thomas D. Otto
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, UnitedKingdom
| | - Chris J. Janse
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Blandine Franke-Fayard
- Leiden Malaria Research Group, Parasitology, Center of infectious Diseases, Leiden University Medical Center (LUMC), Leiden, The Netherlands
- * E-mail:
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Vásquez AM, Blair S, García LF, Segura C. Plasmodium falciparum isolates from patients with uncomplicated malaria promote endothelial inflammation. Microbes Infect 2016; 19:132-141. [PMID: 27717894 DOI: 10.1016/j.micinf.2016.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 09/21/2016] [Accepted: 09/27/2016] [Indexed: 12/23/2022]
Abstract
The ability of Plasmodium falciparum infected erythrocytes (Pf-IEs) to activate endothelial cells has been described; however, the interaction of the endothelium with Pf-IEs field isolates from patients has been less characterized. Previous reports have shown that isolates alter the endothelial permeability and apoptosis. In this study, the adhesion of 19 uncomplicated malaria isolates to Human Dermal Microvascular Endothelial Cells (HDMEC), and their effect on the expression of ICAM-1 and proinflammatory molecules (sICAM-1, IL-6, IL-8, and MCP-1) was evaluated. P. falciparum isolates adhered to resting and TNFα-activated HDEMC cells at different levels. All isolates increased the ICAM-1 expression on the membrane (mICAM-1) of HDMEC and increased the release of its soluble form (sICAM-1), as well the production of IL-6, IL-8 and MCP-1 by HDMEC with no signs of cell apoptosis. No correlation between parasite adhesion and production of cytokines was observed. In conclusion, isolates from uncomplicated malaria can induce a proinflammatory response in endothelial cells that may play a role during the initial inflammatory response to parasite infection; however, a continuous activation of the endothelium can contribute to pathogenesis.
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Affiliation(s)
- Ana María Vásquez
- Grupo Malaria, Universidad de Antioquia, Carrera 53 No. 61 - 30, Lab 610, Medellín, Colombia.
| | - Silvia Blair
- Grupo Malaria, Universidad de Antioquia, Carrera 53 No. 61 - 30, Lab 610, Medellín, Colombia
| | - Luis F García
- Grupo de Inmunología Celular e Inmunogenética (GICIG), Sede de Investigación Universitaria, Universidad de Antioquia, Carrera 53 No. 61 - 30, Lab 410, Medellín, Colombia
| | - Cesar Segura
- Grupo Malaria, Universidad de Antioquia, Carrera 53 No. 61 - 30, Lab 610, Medellín, Colombia
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Endothelin-1 Treatment Induces an Experimental Cerebral Malaria-Like Syndrome in C57BL/6 Mice Infected with Plasmodium berghei NK65. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2957-2969. [PMID: 27640146 DOI: 10.1016/j.ajpath.2016.07.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Revised: 06/06/2016] [Accepted: 07/11/2016] [Indexed: 12/22/2022]
Abstract
Plasmodium berghei ANKA infection of C57BL/6 mice is a widely used model of experimental cerebral malaria (ECM). By contrast, the nonneurotropic P. berghei NK65 (PbN) causes severe malarial disease in C57BL/6 mice but does not cause ECM. Previous studies suggest that endothelin-1 (ET-1) contributes to the pathogenesis of ECM. In this study, we characterize the role of ET-1 on ECM vascular dysfunction. Mice infected with 106 PbN-parasitized red blood cells were treated with either ET-1 or saline from 2 to 8 days postinfection (dpi). Plasmodium berghei ANKA-infected mice served as the positive control. ET-1-treated PbN-infected mice exhibited neurological signs, hypothermia, and behavioral alterations characteristic of ECM, dying 4 to 8 dpi. Parasitemia was not affected by ET-1 treatment. Saline-treated PbN-infected mice did not display ECM, surviving until 12 dpi. ET-1-treated PbN-infected mice displayed leukocyte adhesion to the vascular endothelia and petechial hemorrhages throughout the brain at 6 dpi. Intravital microscopic images demonstrated significant brain arteriolar vessel constriction, decreased functional capillary density, and increased blood-brain barrier permeability. These alterations were not present in either ET-1-treated uninfected or saline-treated PbN-infected mice. In summary, ET-1 treatment of PbN-infected mice induced an ECM-like syndrome, causing brain vasoconstriction, adherence of activated leukocytes in the cerebral microvasculature, and blood-brain barrier leakage, indicating that ET-1 is involved in the genesis of brain microvascular alterations that are the hallmark of ECM.
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64
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Potential cerebral malaria therapy: intramuscular arteether and vitamin D co-administration. Parasitology 2016; 143:1557-68. [DOI: 10.1017/s0031182016001207] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
SUMMARYCerebral malaria (CM) shows lethality rate of 15–25% despite effective antimalarial chemotherapy. The effective adjunct treatment to counteract the CM pathogenesis is urgently required. In murine CM model, most interventions studied till date are administered before the onset of CM symptoms, which belittle its translational value to human. We studied intramuscular arteether–vitamin D (ART–VD) combination treatment for CM outcome improvement after the onset of neurological symptoms. The intramuscular dose of 50 µg kg−1 VD for 3 days combined with a loading dose of 25 mg kg−1α/β arteether followed by 12·5 mg kg−1 dose for two consecutive days led to significant improvement in survival (73% in combination group vs 29 and 0% in arteether and VD monotherapy, respectively) and clinical recovery. The treatment in all the groups partially restored the blood–brain barrier integrity and reduced the level of serum proinflammatory cytokines tumour necrosis factor-α and interferon-γ. The brain transcripts of inflammatory chemokines viz. CXCL10, CXCL9, CCL4 and CCL5 and T cell migration in the brain microvasculature were significantly diminished in all the treatment groups. ART–VD treatment significantly reduced intercellular cell adhesion molecule-1 expression. Taken together, our findings show that coordinated actions of ART–VD improve the outcome of experimental CM.
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Jauréguiberry S, Caumes E. Quand évoquer une cause parasitaire à une infection du système nerveux central ? MEDECINE INTENSIVE REANIMATION 2016. [DOI: 10.1007/s13546-016-1197-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Freeman BD, Martins YC, Akide-Ndunge OB, Bruno FP, Wang H, Tanowitz HB, Spray DC, Desruisseaux MS. Endothelin-1 Mediates Brain Microvascular Dysfunction Leading to Long-Term Cognitive Impairment in a Model of Experimental Cerebral Malaria. PLoS Pathog 2016; 12:e1005477. [PMID: 27031954 PMCID: PMC4816336 DOI: 10.1371/journal.ppat.1005477] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 02/08/2016] [Indexed: 01/29/2023] Open
Abstract
Plasmodium falciparum infection causes a wide spectrum of diseases, including cerebral malaria, a potentially life-threatening encephalopathy. Vasculopathy is thought to contribute to cerebral malaria pathogenesis. The vasoactive compound endothelin-1, a key participant in many inflammatory processes, likely mediates vascular and cognitive dysfunctions in cerebral malaria. We previously demonstrated that C57BL6 mice infected with P. berghei ANKA, our fatal experimental cerebral malaria model, sustained memory loss. Herein, we demonstrate that an endothelin type A receptor (ETA) antagonist prevented experimental cerebral malaria-induced neurocognitive impairments and improved survival. ETA antagonism prevented blood-brain barrier disruption and cerebral vasoconstriction during experimental cerebral malaria, and reduced brain endothelial activation, diminishing brain microvascular congestion. Furthermore, exogenous endothelin-1 administration to P. berghei NK65-infected mice, a model generally regarded as a non-cerebral malaria negative control for P. berghei ANKA infection, led to experimental cerebral malaria-like memory deficits. Our data indicate that endothelin-1 is critical in the development of cerebrovascular and cognitive impairments with experimental cerebral malaria. This vasoactive peptide may thus serve as a potential target for adjunctive therapy in the management of cerebral malaria. The parasite Plasmodium falciparum is the primary cause of cerebral malaria, a neurological manifestation of severe malaria. Cerebral malaria results in disturbances to the blood vessels of the brain, eventually leading to damage to the blood-brain barrier. This damage can lead to adverse, debilitating neurological complications, particularly in children and individuals with compromised immune systems. Yet there is still a considerable gap in understanding the causes of the detrimental neurological effects of P. falciparum infection. We employed a multidisciplinary approach to delineate the mechanisms by which Plasmodium infection causes these abnormalities. The vasoactive peptide endothelin-1 is implicated in a variety of neurological and inflammatory diseases. Using mouse experimental models of cerebral malaria, we demonstrated that targeting this protein resulted in stabilization of the blood vessels in the brain, decreased the influx of inflammatory cells to the brain vessels, and preserved the integrity of the blood-brain barrier, eventually leading to improved cognitive function and improved survival rates in mice with infection. It is our hope that our work will help extend understanding of the causes of cerebral malaria in humans, and may eventually lead to therapies for preservation or salvaging of neurological function in the management of this disease.
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Affiliation(s)
- Brandi D. Freeman
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Yuri C. Martins
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Oscar B. Akide-Ndunge
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Fernando P. Bruno
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Hua Wang
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Herbert B. Tanowitz
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - David C. Spray
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Mahalia S. Desruisseaux
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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67
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Panackal AA, Williamson KC, van de Beek D, Boulware DR, Williamson PR. Fighting the Monster: Applying the Host Damage Framework to Human Central Nervous System Infections. mBio 2016; 7:e01906-15. [PMID: 26814182 PMCID: PMC4742705 DOI: 10.1128/mbio.01906-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The host damage-response framework states that microbial pathogenesis is a product of microbial virulence factors and collateral damage from host immune responses. Immune-mediated host damage is particularly important within the size-restricted central nervous system (CNS), where immune responses may exacerbate cerebral edema and neurological damage, leading to coma and death. In this review, we compare human host and therapeutic responses in representative nonviral generalized CNS infections that induce archetypal host damage responses: cryptococcal menigoencephalitis and tuberculous meningitis in HIV-infected and non-HIV-infected patients, pneumococcal meningitis, and cerebral malaria. Consideration of the underlying patterns of host responses provides critical insights into host damage and may suggest tailored adjunctive therapeutics to improve disease outcome.
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Affiliation(s)
- Anil A Panackal
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Kim C Williamson
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland, USA
| | - Diederik van de Beek
- Department of Neurology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - David R Boulware
- Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Peter R Williamson
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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68
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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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69
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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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Sahu PK, Satpathi S, Behera PK, Mishra SK, Mohanty S, Wassmer SC. Pathogenesis of cerebral malaria: new diagnostic tools, biomarkers, and therapeutic approaches. Front Cell Infect Microbiol 2015; 5:75. [PMID: 26579500 PMCID: PMC4621481 DOI: 10.3389/fcimb.2015.00075] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/05/2015] [Indexed: 12/28/2022] Open
Abstract
Cerebral malaria is a severe neuropathological complication of Plasmodium falciparum infection. It results in high mortality and post-recovery neuro-cognitive disorders in children, even after appropriate treatment with effective anti-parasitic drugs. While the complete landscape of the pathogenesis of cerebral malaria still remains to be elucidated, numerous innovative approaches have been developed in recent years in order to improve the early detection of this neurological syndrome and, subsequently, the clinical care of affected patients. In this review, we briefly summarize the current understanding of cerebral malaria pathogenesis, compile the array of new biomarkers and tools available for diagnosis and research, and describe the emerging therapeutic approaches to tackle this pathology effectively.
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Affiliation(s)
- Praveen K Sahu
- Center for the Study of Complex Malaria in India, Ispat General Hospital Rourkela, India
| | | | | | - Saroj K Mishra
- Center for the Study of Complex Malaria in India, Ispat General Hospital Rourkela, India
| | - Sanjib Mohanty
- Center for the Study of Complex Malaria in India, Ispat General Hospital Rourkela, India
| | - Samuel Crocodile Wassmer
- Department of Microbiology, New York University School of Medicine New York, NY, USA ; Department of Pathology, The University of Sydney Sydney, NSW, Australia
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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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Fatal Pediatric Cerebral Malaria Is Associated with Intravascular Monocytes and Platelets That Are Increased with HIV Coinfection. mBio 2015; 6:e01390-15. [PMID: 26396242 PMCID: PMC4611030 DOI: 10.1128/mbio.01390-15] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cerebral malaria (CM) is a major contributor to malaria deaths, but its pathophysiology is not well understood. While sequestration of parasitized erythrocytes is thought to be critical, the roles of inflammation and coagulation are controversial. In a large series of Malawian children hospitalized with CM, HIV coinfection was more prevalent than in pediatric population estimates (15% versus 2%, P < 0.0001, chi-square test), with higher mortality than that seen in HIV-uninfected children (23% versus 17%, P = 0.0178, chi-square test). HIV-infected (HIV+) children with autopsy-confirmed CM were older than HIV-uninfected children (median age, 99 months versus 32 months, P = 0.0007, Mann-Whitney U test) and appeared to lack severe immunosuppression. Because HIV infection is associated with dysregulated inflammation and platelet activation, we performed immunohistochemistry analysis for monocytes, platelets, and neutrophils in brain tissue from HIV+ and HIV-uninfected children with fatal CM. Children with autopsy-confirmed CM had significantly (>9 times) more accumulations of intravascular monocytes and platelets, but not neutrophils, than did children with nonmalarial causes of coma. The monocyte and platelet accumulations were significantly (>2-fold) greater in HIV+ children than in HIV-uninfected children with autopsy-confirmed CM. Our findings indicate that HIV is a risk factor for CM and for death from CM, independent of traditional measures of HIV disease severity. Brain histopathology supports the hypotheses that inflammation and coagulation contribute to the pathogenesis of pediatric CM and that immune dysregulation in HIV+ children exacerbates the pathological features associated with CM. Importance There are nearly 1 million malaria deaths yearly, primarily in sub-Saharan African children. Cerebral malaria (CM), marked by coma and sequestered malaria parasites in brain blood vessels, causes half of these deaths, although the mechanisms causing coma and death are uncertain. Sub-Saharan Africa has a high HIV prevalence, with 3 million HIV-infected (HIV+) children, but the effects of HIV on CM pathogenesis and mortality are unknown. In a study of pediatric CM in Malawi, HIV prevalence was high and CM-attributed mortality was higher in HIV+ than in HIV-uninfected children. Brain pathology in children with fatal CM was notable not only for sequestered malaria parasites but also for intravascular accumulations of monocytes and platelets that were more severe in HIV+ children. Our findings raise the possibility that HIV+ children at risk for malaria may benefit from targeted malaria prophylaxis and that adjunctive treatments targeting inflammation and/or coagulation may improve CM outcomes. There are nearly 1 million malaria deaths yearly, primarily in sub-Saharan African children. Cerebral malaria (CM), marked by coma and sequestered malaria parasites in brain blood vessels, causes half of these deaths, although the mechanisms causing coma and death are uncertain. Sub-Saharan Africa has a high HIV prevalence, with 3 million HIV-infected (HIV+) children, but the effects of HIV on CM pathogenesis and mortality are unknown. In a study of pediatric CM in Malawi, HIV prevalence was high and CM-attributed mortality was higher in HIV+ than in HIV-uninfected children. Brain pathology in children with fatal CM was notable not only for sequestered malaria parasites but also for intravascular accumulations of monocytes and platelets that were more severe in HIV+ children. Our findings raise the possibility that HIV+ children at risk for malaria may benefit from targeted malaria prophylaxis and that adjunctive treatments targeting inflammation and/or coagulation may improve CM outcomes.
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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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Wassmer SC, Taylor TE, Rathod PK, Mishra SK, Mohanty S, Arevalo-Herrera M, Duraisingh MT, Smith JD. Investigating the Pathogenesis of Severe Malaria: A Multidisciplinary and Cross-Geographical Approach. Am J Trop Med Hyg 2015; 93:42-56. [PMID: 26259939 PMCID: PMC4574273 DOI: 10.4269/ajtmh.14-0841] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 03/10/2015] [Indexed: 01/14/2023] Open
Abstract
More than a century after the discovery of Plasmodium spp. parasites, the pathogenesis of severe malaria is still not well understood. The majority of malaria cases are caused by Plasmodium falciparum and Plasmodium vivax, which differ in virulence, red blood cell tropism, cytoadhesion of infected erythrocytes, and dormant liver hypnozoite stages. Cerebral malaria coma is one of the most severe manifestations of P. falciparum infection. Insights into its complex pathophysiology are emerging through a combination of autopsy, neuroimaging, parasite binding, and endothelial characterizations. Nevertheless, important questions remain regarding why some patients develop life-threatening conditions while the majority of P. falciparum-infected individuals do not, and why clinical presentations differ between children and adults. For P. vivax, there is renewed recognition of severe malaria, but an understanding of the factors influencing disease severity is limited and remains an important research topic. Shedding light on the underlying disease mechanisms will be necessary to implement effective diagnostic tools for identifying and classifying severe malaria syndromes and developing new therapeutic approaches for severe disease. This review highlights progress and outstanding questions in severe malaria pathophysiology and summarizes key areas of pathogenesis research within the International Centers of Excellence for Malaria Research program.
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Affiliation(s)
| | | | | | | | | | | | | | - Joseph D. Smith
- Division of Parasitology, Department of Microbiology, New York University School of Medicine, New York, New York; Department of Pathology, Sydney Medical School, The University of Sydney, Sydney, Australia; Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan; Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi; Departments of Chemistry and Global Health, University of Washington, Seattle, Washington; Department of Internal Medicine, Ispat General Hospital, Orissa, India; Caucaseco Scientific Research Center, Cali, Colombia; Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts; Seattle Biomedical Research Institute, Seattle, Washington; Department of Global Health, University of Washington, Seattle, Washington
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75
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Lombardini ED, Gettayacamin M, Turner GDH, Brown AE. A Review of Plasmodium coatneyi-Macaque Models of Severe Malaria. Vet Pathol 2015; 52:998-1011. [PMID: 26077782 DOI: 10.1177/0300985815583098] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Malaria remains one of the most significant public health concerns in the world today. Approximately half the human population is at risk for infection, with children and pregnant women being most vulnerable. More than 90% of the total human malaria burden, which numbers in excess of 200 million annually, is due to Plasmodium falciparum. Lack of an effective vaccine and a dwindling stockpile of antimalarial drugs due to increased plasmodial resistance underscore the critical need for valid animal models. Plasmodium coatneyi was described in Southeast Asia 50 years ago. This plasmodium of nonhuman primates has been used sporadically as a model for severe malaria, as it mimics many of the pathophysiologic features of human disease. This review covers the reported macroscopic, microscopic, ultrastructural, and molecular pathology of P. coatneyi infection in macaques, specifically focusing on the rhesus macaque, as well as describing the critical needs still outstanding in the validation of this crucial model of human disease.
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Affiliation(s)
- E D Lombardini
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - M Gettayacamin
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - G D H Turner
- Mahidol Oxford Clinical Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - A E Brown
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
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76
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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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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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Human infections with Plasmodium knowlesi--zoonotic malaria. Clin Microbiol Infect 2015; 21:640-8. [PMID: 25843504 DOI: 10.1016/j.cmi.2015.03.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 03/09/2015] [Accepted: 03/19/2015] [Indexed: 11/21/2022]
Abstract
In 2004 a large focus of Plasmodium knowlesi malaria was reported in the human population in Sarawak, Malaysian Borneo. Plasmodium knowlesi, a parasite of the South-East Asian macaques (Macaca fascicularis and Macaca nemestrina), had entered the human population. Plasmodium knowlesi is transmitted by the leucosphyrus group of Anopheline mosquitoes and transmission is largely zoonotic and restricted to the jungle setting. Humans entering jungle transmission sites are at risk. Since 2004, human cases of P. knowlesi have been continuously reported in local communities and in travellers returning from South East Asia. Plasmodium knowlesi is the most common type of indigenous malaria reported in Malaysia. Infections are most often uncomplicated but at least 10% of patients report with severe malaria and 1-2% of cases have a fatal outcome. Parasitaemia is positively associated with the clinical and laboratory markers of severe malaria. The current literature on P. knowlesi, including epidemiology, natural hosts and vectors, pathogenesis, clinical descriptions, treatment and diagnosis, is reviewed. There are many gaps in our understanding of this disease that are highlighted here with suggestions for further research to inform pre-emptive control measures that would be required to prevent a full emergence of this parasite into the human population.
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79
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In Vivo Function of PTEX88 in Malaria Parasite Sequestration and Virulence. EUKARYOTIC CELL 2015; 14:528-34. [PMID: 25820521 DOI: 10.1128/ec.00276-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 03/25/2015] [Indexed: 01/07/2023]
Abstract
Malaria pathology is linked to remodeling of red blood cells by eukaryotic Plasmodium parasites. Central to host cell refurbishment is the trafficking of parasite-encoded virulence factors through the Plasmodium translocon of exported proteins (PTEX). Much of our understanding of its function is based on experimental work with cultured Plasmodium falciparum, yet direct consequences of PTEX impairment during an infection remain poorly defined. Using the murine malaria model parasite Plasmodium berghei, it is shown here that efficient sequestration to the pulmonary, adipose, and brain tissue vasculature is dependent on the PTEX components thioredoxin 2 (TRX2) and PTEX88. While TRX2-deficient parasites remain virulent, PTEX88-deficient parasites no longer sequester in the brain, correlating with abolishment of cerebral complications in infected mice. However, an apparent trade-off for virulence attenuation was spleen enlargement, which correlates with a strongly reduced schizont-to-ring-stage transition. Strikingly, general protein export is unaffected in PTEX88-deficient mutants that mature normally in vitro. Thus, PTEX88 is pivotal for tissue sequestration in vivo, parasite virulence, and preventing exacerbation of spleen pathology, but these functions do not correlate with general protein export to the host erythrocyte. The presented data suggest that the protein export machinery of Plasmodium parasites and their underlying mechanistic features are considerably more complex than previously anticipated and indicate challenges for targeted intervention strategies.
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Seydel KB, Kampondeni SD, Valim C, Potchen MJ, Milner DA, Muwalo FW, Birbeck GL, Bradley WG, Fox LL, Glover SJ, Hammond CA, Heyderman RS, Chilingulo CA, Molyneux ME, Taylor TE. Brain swelling and death in children with cerebral malaria. N Engl J Med 2015; 372:1126-37. [PMID: 25785970 PMCID: PMC4450675 DOI: 10.1056/nejmoa1400116] [Citation(s) in RCA: 270] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND Case fatality rates among African children with cerebral malaria remain in the range of 15 to 25%. The key pathogenetic processes and causes of death are unknown, but a combination of clinical observations and pathological findings suggests that increased brain volume leading to raised intracranial pressure may play a role. Magnetic resonance imaging (MRI) became available in Malawi in 2009, and we used it to investigate the role of brain swelling in the pathogenesis of fatal cerebral malaria in African children. METHODS We enrolled children who met a stringent definition of cerebral malaria (one that included the presence of retinopathy), characterized them in detail clinically, and obtained MRI scans on admission and daily thereafter while coma persisted. RESULTS Of 348 children admitted with cerebral malaria (as defined by the World Health Organization), 168 met the inclusion criteria, underwent all investigations, and were included in the analysis. A total of 25 children (15%) died, 21 of whom (84%) had evidence of severe brain swelling on MRI at admission. In contrast, evidence of severe brain swelling was seen on MRI in 39 of 143 survivors (27%). Serial MRI scans showed evidence of decreasing brain volume in the survivors who had had brain swelling initially. CONCLUSIONS Increased brain volume was seen in children who died from cerebral malaria but was uncommon in those who did not die from the disease, a finding that suggests that raised intracranial pressure may contribute to a fatal outcome. The natural history indicates that increased intracranial pressure is transient in survivors. (Funded by the National Institutes of Health and Wellcome Trust U.K.).
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Affiliation(s)
- Karl B Seydel
- From the Department of Osteopathic Medical Specialties, College of Osteopathic Medicine (K.B.S., L.L.F., T.E.T.), Department of Radiology (M.J.P., C.A.H.), and Department of Neurology and Ophthalmology, International Neurologic and Psychiatric Epidemiology Program (G.L.B.), Michigan State University, East Lansing; the Blantyre Malaria Project (K.B.S., S.D.K., D.A.M., F.W.M., L.L.F., T.E.T.) and Malawi-Liverpool-Wellcome Trust Clinical Research Programme (R.S.H., M.E.M.), Queen Elizabeth Central Hospital (S.D.K., C.A.C.) and the Department of Anatomy (S.J.G.), University of Malawi College of Medicine - both in Blantyre, Malawi; the Department of Immunology and Infectious Diseases, Harvard School of Public Health (C.V., D.A.M.), and the Department of Pathology, Brigham and Women's Hospital (D.A.M.) - both in Boston; the Department of Radiology, University of California San Diego, San Diego (W.G.B.); and the Liverpool School of Tropical Medicine, Liverpool, United Kingdom (M.E.M.)
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Recuenco FC, Takano R, Chiba S, Sugi T, Takemae H, Murakoshi F, Ishiwa A, Inomata A, Horimoto T, Kobayashi Y, Horiuchi N, Kato K. Lambda-carrageenan treatment exacerbates the severity of cerebral malaria caused by Plasmodium berghei ANKA in BALB/c mice. Malar J 2014; 13:487. [PMID: 25495520 PMCID: PMC4295290 DOI: 10.1186/1475-2875-13-487] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/07/2014] [Indexed: 12/31/2022] Open
Abstract
Background There is an urgent need to develop and test novel compounds against malaria infection. Carrageenans, sulphated polysaccharides derived from seaweeds, have been previously shown to inhibit Plasmodium falciparum in vitro. However, they are inflammatory and alter the permeability of the blood–brain barrier, raising concerns that their use as a treatment for malaria could lead to cerebral malaria (CM), a severe complication of the disease. In this work, the authors look into the effects of the administration of λ-carrageenan to the development and severity of CM in BALB/c mice, a relatively non-susceptible model, during infection with the ANKA strain of Plasmodium berghei. Methods Five-week-old female BALB/c mice were infected with P. berghei intraperitoneally. One group was treated with λ-carrageenan (PbCGN) following the 4-day suppressive test protocol, whereas the other group was not treated (PbN). Another group of healthy BALB/c mice was similarly given λ-carrageenan (CGN) for comparison. The following parameters were assessed: parasitaemia, clinical signs of CM, and mortality. Brain and other vital organs were collected and examined for gross and histopathological lesions. Evans blue dye assays were employed to assess blood–brain barrier integrity. Results Plasmodium berghei ANKA-infected BALB/c mice treated with λ-carrageenan died earlier than those that received no treatment. Histopathological examination revealed that intracerebral haemorrhages related to CM were present in both groups of infected BALB/c mice, but were more numerous in those treated with λ-carrageenan than in mock-treated animals. Inflammatory lesions were also observed only in the λ-carrageenan-treated mice. These observations are consistent with the clinical signs associated with CM, such as head tilt, convulsions, and coma, which were observed only in this group, and may account for the earlier death of the mice. Conclusion The results of this study indicate that the administration of λ-carrageenan exacerbates the severe brain lesions and clinical signs associated with CM in BALB/c mice infected with P. berghei ANKA.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | - Kentaro Kato
- Department of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
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Soltanifar D, Carvalho B, Sultan P. Perioperative considerations of the patient with malaria. Can J Anaesth 2014; 62:304-18. [PMID: 25471683 PMCID: PMC7102007 DOI: 10.1007/s12630-014-0286-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 11/25/2014] [Indexed: 11/28/2022] Open
Abstract
Purpose Malaria is a life-threatening infectious disease caused by the Plasmodium parasite. Increased global travel has resulted in an escalation in the number of imported cases seen in developed countries. Patients with malaria may present for surgery in both endemic and non-endemic countries. This article reviews the perioperative considerations when managing patients with malaria. Source A literature review of anesthesia, perioperative care, and malaria-related articles was performed using the MEDLINE®, EMBASE™, and Web of Science databases to identify relevant articles published in English during 1945-2014. Of the 303 articles matching the search criteria, 265 were excluded based on title and abstract. Eleven of the remaining 38 articles were relevant to anesthesia/perioperative care, and 27 articles were identified as having direct relevance to critical care medicine. Principal findings The majority of imported malaria cases are caused by the falciparum species, which is associated with the greatest degree of morbidity and mortality. Various organ systems may be impacted as a consequence of changes in the structure and function of parasitized erythrocytes. Preoperative assessment should focus on establishing the species of malaria, the severity of disease, assessing the degree of end-organ impairment, and initiating treatment of malaria prior to surgery. Intravenous artesunate is the treatment of choice for severe falciparum malaria. Quinine is a second-line agent but has a narrow therapeutic index and particularly hazardous side effects. Intraoperatively, attention should focus on fluid management, dynamics of cerebral blood flow, and avoidance of hypoglycemia. Postoperative care of severe cases should ideally take place in a critical care unit as there may be ongoing requirements for multi-organ support, including renal replacement therapy, ventilation, and/or inotropic support. The safety of neuraxial anesthesia has not been well studied in the setting of malaria. Conclusions Malaria remains one of the most devastating infectious diseases worldwide. Multiple organ systems can be impacted as a consequence of changes in structure and function of parasitized erythrocytes. Safe perioperative management requires a sound knowledge of all these potential system effects.
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Hanson J, Anstey NM, Bihari D, White NJ, Day NP, Dondorp AM. The fluid management of adults with severe malaria. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:642. [PMID: 25629462 PMCID: PMC4318383 DOI: 10.1186/s13054-014-0642-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Fluid resuscitation has long been considered a key intervention in the treatment of adults with severe falciparum malaria. Profound hypovolemia is common in these patients and has the potential to exacerbate the acidosis and acute kidney injury that are independent predictors of death. However, new microvascular imaging techniques have shown that disease severity correlates more strongly with obstruction of the microcirculation by parasitized erythrocytes - a process termed sequestration. Fluid loading has little effect on sequestration and increases the risk of complications, particularly pulmonary edema, a condition that can develop suddenly and unpredictably and that is frequently fatal in this population. Accordingly, even if a patient is clinically hypovolemic, if there is an adequate blood pressure and urine output, there may be little advantage in infusing intravenous fluid beyond a maintenance rate of 1 to 2 mL/kg per hour. The optimal agent for fluid resuscitation remains uncertain; significant anemia requires blood transfusion, but colloid solutions may be associated with harm and should be avoided. The preferred crystalloid is unclear, although the use of balanced solutions requires investigation. There are fewer data to guide the fluid management of severe vivax and knowlesi malaria, although a similar conservative strategy would appear prudent.
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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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Hunt NH, Ball HJ, Hansen AM, Khaw LT, Guo J, Bakmiwewa S, Mitchell AJ, Combes V, Grau GER. Cerebral malaria: gamma-interferon redux. Front Cell Infect Microbiol 2014; 4:113. [PMID: 25177551 PMCID: PMC4133756 DOI: 10.3389/fcimb.2014.00113] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 07/30/2014] [Indexed: 11/13/2022] Open
Abstract
There are two theories that seek to explain the pathogenesis of cerebral malaria, the mechanical obstruction hypothesis and the immunopathology hypothesis. Evidence consistent with both ideas has accumulated from studies of the human disease and experimental models. Thus, some combination of these concepts seems necessary to explain the very complex pattern of changes seen in cerebral malaria. The interactions between malaria parasites, erythrocytes, the cerebral microvascular endothelium, brain parenchymal cells, platelets and microparticles need to be considered. One factor that seems able to knit together much of this complexity is the cytokine interferon-gamma (IFN-γ). In this review we consider findings from the clinical disease, in vitro models and the murine counterpart of human cerebral malaria in order to evaluate the roles played by IFN-γ in the pathogenesis of this often fatal and debilitating condition.
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Affiliation(s)
- Nicholas H Hunt
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Helen J Ball
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Anna M Hansen
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Loke T Khaw
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Jintao Guo
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Supun Bakmiwewa
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Andrew J Mitchell
- Molecular Immunopathology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Valéry Combes
- Vascular Immunology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
| | - Georges E R Grau
- Vascular Immunology Unit, School of Medical Sciences and Bosch Institute, University of Sydney Sydney, NSW, Australia
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87
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Maturation of Plasmodium falciparum in multiply infected erythrocytes and the potential role in malaria pathogenesis. Parasitol Res 2014; 113:4045-56. [DOI: 10.1007/s00436-014-4073-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/05/2014] [Indexed: 10/24/2022]
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88
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Storm J, Craig AG. Pathogenesis of cerebral malaria--inflammation and cytoadherence. Front Cell Infect Microbiol 2014; 4:100. [PMID: 25120958 PMCID: PMC4114466 DOI: 10.3389/fcimb.2014.00100] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/07/2014] [Indexed: 01/08/2023] Open
Abstract
Despite decades of research on cerebral malaria (CM) there is still a paucity of knowledge about what actual causes CM and why certain people develop it. Although sequestration of P. falciparum infected red blood cells has been linked to pathology, it is still not clear if this is directly or solely responsible for this clinical syndrome. Recent data have suggested that a combination of parasite variant types, mainly defined by the variant surface antigen, P. falciparum erythrocyte membrane protein 1 (PfEMP1), its receptors, coagulation and host endothelial cell activation (or inflammation) are equally important. This makes CM a multi-factorial disease and a challenge to unravel its causes to decrease its detrimental impact.
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Affiliation(s)
- Janet Storm
- Department of Parasitology, Liverpool School of Tropical Medicine Liverpool, UK ; Malawi Liverpool Wellcome Trust Clinical Research Programme (MLW), University of Malawi College of Medicine Blantyre, Malawi
| | - Alister G Craig
- Department of Parasitology, Liverpool School of Tropical Medicine Liverpool, UK
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89
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Mohanty S, Taylor TE, Kampondeni S, Potchen MJ, Panda P, Majhi M, Mishra SK, Wassmer SC. Magnetic resonance imaging during life: the key to unlock cerebral malaria pathogenesis? Malar J 2014; 13:276. [PMID: 25038815 PMCID: PMC4114090 DOI: 10.1186/1475-2875-13-276] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 07/14/2014] [Indexed: 12/22/2022] Open
Abstract
Understanding the mechanisms underlying the pathophysiology of cerebral malaria in patients with Plasmodium falciparum infection is necessary to implement new curative interventions. While autopsy-based studies shed some light on several pathological events that are believed to be crucial in the development of this neurologic syndrome, their investigative potential is limited and has not allowed the identification of causes of death in patients who succumb to it. This can only be achieved by comparing features between patients who die from cerebral malaria and those who survive. In this review, several alternative approaches recently developed to facilitate the comparison of specific parameters between fatal, non-fatal cerebral malaria and uncomplicated malaria patients are described, as well as their limitations. The emergence of neuroimaging as a revolutionary tool in identifying critical structural and functional modifications of the brain during cerebral malaria is discussed and highly promising areas of clinical research using magnetic resonance imaging are highlighted.
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Affiliation(s)
| | | | | | | | | | | | | | - Samuel C Wassmer
- Department of Microbiology, Division of Parasitology, New York University School of Medicine, 341 East 25th Street, New York NY 10010, USA.
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90
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Penha-Gonçalves C, Gozzelino R, de Moraes LV. Iron overload in Plasmodium berghei-infected placenta as a pathogenesis mechanism of fetal death. Front Pharmacol 2014; 5:155. [PMID: 25071574 PMCID: PMC4077027 DOI: 10.3389/fphar.2014.00155] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/12/2014] [Indexed: 11/17/2022] Open
Abstract
Plasmodium infection during gestation may lead to severe clinical manifestations including abortion, stillbirth, intrauterine growth retardation, and low birth weight. Mechanisms underlying such poor pregnancy outcomes are still unclear. In the animal model of severe placental malaria (PM), in utero fetal death frequently occurs and mothers often succumb to infection before or immediately after delivery. Plasmodium berghei-infected erythrocytes (IEs) continuously accumulate in the placenta, where they are then phagocytosed by fetal-derived placental cells, namely trophoblasts. Inside the phagosomes, disruption of IEs leads to the release of non-hemoglobin bound heme, which is subsequently catabolized by heme oxygenase-1 into carbon monoxide, biliverdin, and labile iron. Fine-tuned regulatory mechanisms operate to maintain iron homeostasis, preventing the deleterious effect of iron-induced oxidative stress. Our preliminary results demonstrate that iron overload in trophoblasts of P. berghei-infected placenta is associated with fetal death. Placentas which supported normally developing embryos showed no iron accumulation within the trophoblasts. Placentas from dead fetuses showed massive iron accumulation, which was associated with parasitic burden. Here we present preliminary data suggesting that disruption of iron homeostasis in trophoblasts during the course of PM is a consequence of heme accumulation after intense IE engulfment. We propose that iron overload in placenta is a pathogenic component of PM, contributing to fetal death. The mechanism through which it operates still needs to be elucidated.
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91
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Marks M, Gupta-Wright A, Doherty JF, Singer M, Walker D. Managing malaria in the intensive care unit. Br J Anaesth 2014; 113:910-21. [PMID: 24946778 PMCID: PMC4235570 DOI: 10.1093/bja/aeu157] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The number of people travelling to malaria-endemic countries continues to increase, and malaria remains the commonest cause of serious imported infection in non-endemic areas. Severe malaria, mostly caused by Plasmodium falciparum, often requires intensive care unit (ICU) admission and can be complicated by cerebral malaria, respiratory distress, acute kidney injury, bleeding complications, and co-infection. The mortality from imported malaria remains significant. This article reviews the manifestations, complications and principles of management of severe malaria as relevant to critical care clinicians, incorporating recent studies of anti-malarial and adjunctive treatment. Effective management of severe malaria includes prompt diagnosis and early institution of effective anti-malarial therapy, recognition of complications, and appropriate supportive management in an ICU. All cases should be discussed with a specialist unit and transfer of the patient considered.
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Affiliation(s)
- M Marks
- The Hospital for Tropical Diseases, Mortimer Market Centre, Capper Street, London, UK Department of Clinical Research, Faculty of Infectious and Tropical Diseases London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - A Gupta-Wright
- The Hospital for Tropical Diseases, Mortimer Market Centre, Capper Street, London, UK Department of Clinical Research, Faculty of Infectious and Tropical Diseases London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - J F Doherty
- The Hospital for Tropical Diseases, Mortimer Market Centre, Capper Street, London, UK
| | - M Singer
- Department of Critical Care, University College London Hospital NHS Foundation Trust, 3rd Floor, 235 Euston Road, London NW1 2BU, UK
| | - D Walker
- Department of Critical Care, University College London Hospital NHS Foundation Trust, 3rd Floor, 235 Euston Road, London NW1 2BU, UK
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92
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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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Pusiol T, Lavezzi AM, Radice F, Alfonsi G, Matturri L. Unsuspected imported malaria in a case of sudden infant death. World J Clin Infect Dis 2014; 4:5-8. [DOI: 10.5495/wjcid.v4.i2.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 07/23/2014] [Accepted: 08/31/2014] [Indexed: 02/06/2023] Open
Abstract
Here we describe the case of a 4-mo-old female who died suddenly without any apparent cause that was initially mistaken as a case of sudden infant death syndrome. Histologic observation of brain sections revealed blue-black bodies in erythrocytes of the blood vessels, suggestive of specific stages of the hematic schizogonic cycle. Further examinations revealed hemozoin and hemosiderin deposits in the parenchyma of all organs, leading to the diagnosis of malaria by Plasmodium falciparum (P. falciparum). The death occurred in Italy, the native country of the infant, two weeks after a Christmas holiday spent in Pakistan, the parents’ birthplace, which has a high malarial endemicity. As this case demonstrates, the diagnosis of malaria should always be considered as a differential diagnosis in subjects, including infants, that die unexpectedly after returning from P. falciparum endemic areas.
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94
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Punsawad C. Effect of malaria components on blood mononuclear cells involved in immune response. Asian Pac J Trop Biomed 2014; 3:751-6. [PMID: 23998019 DOI: 10.1016/s2221-1691(13)60151-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 07/18/2013] [Indexed: 01/06/2023] Open
Abstract
During malaria infection, elevated levels of pro-inflammatory mediators and nitric oxide production have been associated with pathogenesis and disease severity. Previous in vitro and in vivo studies have proposed that both Plasmodium falciparum hemozoin and glycosylphosphatidylinositols are able to modulate blood mononuclear cells, contributing to stimulation of signal transduction and downstream regulation of the NF-κB signaling pathway, and subsequently leading to the production of pro-inflammatory cytokines, chemokines, and nitric oxide. The present review summarizes the published in vitro and in vivo studies that have investigated the mechanism of intracellular signal transduction and activation of the NF-κB signaling pathway in blood mononuclear cells after being inducted by Plasmodium falciparum malaria components. Particular attention is paid to hemozoin and glycosylphosphatidylinositols which reflect the important mechanism of signaling pathways involved in immune response.
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Affiliation(s)
- Chuchard Punsawad
- School of Medicine, Walailak University, 222 Thasala District, Nakhon Si Thammarat 80161, Thailand.
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95
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Maude RJ, Barkhof F, Hassan MU, Ghose A, Hossain A, Abul Faiz M, Choudhury E, Rashid R, Abu Sayeed A, Charunwatthana P, Plewes K, Kingston H, Maude RR, Silamut K, Day NPJ, White NJ, Dondorp AM. Magnetic resonance imaging of the brain in adults with severe falciparum malaria. Malar J 2014; 13:177. [PMID: 24884982 PMCID: PMC4024626 DOI: 10.1186/1475-2875-13-177] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 05/02/2014] [Indexed: 12/15/2022] Open
Abstract
Background Magnetic resonance imaging (MRI) allows detailed study of structural and functional changes in the brain in patients with cerebral malaria. Methods In a prospective observational study in adult Bangladeshi patients with severe falciparum malaria, MRI findings in the brain were correlated with clinical and laboratory parameters, retinal photography and optic nerve sheath diameter (ONSD) ultrasound (a marker of intracranial pressure). Results Of 43 enrolled patients, 31 (72%) had coma and 12 (28%) died. MRI abnormalities were present in 79% overall with mostly mild changes in a wide range of anatomical sites. There were no differences in MRI findings between patients with cerebral and non-cerebral or fatal and non-fatal disease. Subtle diffuse cerebral swelling was common (n = 22/43), but mostly without vasogenic oedema or raised intracranial pressure (ONSD). Also seen were focal extracellular oedema (n = 11/43), cytotoxic oedema (n = 8/23) and mildly raised brain lactate on magnetic resonance spectroscopy (n = 5/14). Abnormalities were much less prominent than previously described in Malawian children. Retinal whitening was present in 36/43 (84%) patients and was more common and severe in patients with coma. Conclusion Cerebral swelling is mild and not specific to coma or death in adult severe falciparum malaria. This differs markedly from African children. Retinal whitening, reflecting heterogeneous obstruction of the central nervous system microcirculation by sequestered parasites resulting in small patches of ischemia, is associated with coma and this process is likely important in the pathogenesis.
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Affiliation(s)
- Richard James Maude
- Centre for Tropical Medicine, Nuffield Department of Medicine, University of Oxford, Old Road, Oxford OX3 7LJ, UK.
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96
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Bachmann J, Burté F, Pramana S, Conte I, Brown BJ, Orimadegun AE, Ajetunmobi WA, Afolabi NK, Akinkunmi F, Omokhodion S, Akinbami FO, Shokunbi WA, Kampf C, Pawitan Y, Uhlén M, Sodeinde O, Schwenk JM, Wahlgren M, Fernandez-Reyes D, Nilsson P. Affinity proteomics reveals elevated muscle proteins in plasma of children with cerebral malaria. PLoS Pathog 2014; 10:e1004038. [PMID: 24743550 PMCID: PMC3990714 DOI: 10.1371/journal.ppat.1004038] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 02/06/2014] [Indexed: 01/21/2023] Open
Abstract
Systemic inflammation and sequestration of parasitized erythrocytes are central processes in the pathophysiology of severe Plasmodium falciparum childhood malaria. However, it is still not understood why some children are more at risks to develop malaria complications than others. To identify human proteins in plasma related to childhood malaria syndromes, multiplex antibody suspension bead arrays were employed. Out of the 1,015 proteins analyzed in plasma from more than 700 children, 41 differed between malaria infected children and community controls, whereas 13 discriminated uncomplicated malaria from severe malaria syndromes. Markers of oxidative stress were found related to severe malaria anemia while markers of endothelial activation, platelet adhesion and muscular damage were identified in relation to children with cerebral malaria. These findings suggest the presence of generalized vascular inflammation, vascular wall modulations, activation of endothelium and unbalanced glucose metabolism in severe malaria. The increased levels of specific muscle proteins in plasma implicate potential muscle damage and microvasculature lesions during the course of cerebral malaria. Why do some malaria-infected children develop severe and lethal forms of the disease, while others only have mild forms? In order to try to find potential answers or clues to this question, we have here analyzed more than 1,000 different human proteins in the blood of more than 500 malaria-infected children from Ibadan in Nigeria, a holoendemic malaria region. We identified several proteins that were present at higher levels in the blood from the children that developed severe malaria in comparison to those that did not. Some of the most interesting identified proteins were muscle specific proteins, which indicate that damaged muscles could be a discriminatory pathologic event in cerebral malaria compared to other malaria cases. These findings will hopefully lead to an increased understanding of the disease and may contribute to the development of clinical algorithms that could predict which children are more at risks to severe malaria. This in turn will be of high value in the management of these children in already overloaded tertiary-care health facilities in urban large densely-populated sub-Saharan cities with holoendemic malaria such as in the case of Ibadan and Lagos.
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Affiliation(s)
- Julie Bachmann
- SciLifeLab Stockholm, School of Biotechnology, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Florence Burté
- Division of Parasitology, Medical Research Council National Institute for Medical Research, London, United Kingdom
| | - Setia Pramana
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Ianina Conte
- Division of Parasitology, Medical Research Council National Institute for Medical Research, London, United Kingdom
| | - Biobele J. Brown
- Department of Paediatrics, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
- Department of Haematology, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
- Childhood Malaria Research Group, University College Hospital, Ibadan, Nigeria
| | - Adebola E. Orimadegun
- Department of Paediatrics, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
| | - Wasiu A. Ajetunmobi
- Department of Paediatrics, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
| | - Nathaniel K. Afolabi
- Department of Paediatrics, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
| | - Francis Akinkunmi
- Department of Paediatrics, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
| | - Samuel Omokhodion
- Department of Paediatrics, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
- Childhood Malaria Research Group, University College Hospital, Ibadan, Nigeria
| | - Felix O. Akinbami
- Department of Paediatrics, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
- Childhood Malaria Research Group, University College Hospital, Ibadan, Nigeria
| | - Wuraola A. Shokunbi
- Department of Haematology, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
- Childhood Malaria Research Group, University College Hospital, Ibadan, Nigeria
| | - Caroline Kampf
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
| | - Yudi Pawitan
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Mathias Uhlén
- SciLifeLab Stockholm, School of Biotechnology, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Olugbemiro Sodeinde
- Division of Parasitology, Medical Research Council National Institute for Medical Research, London, United Kingdom
- Department of Paediatrics, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
- Department of Haematology, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
- Childhood Malaria Research Group, University College Hospital, Ibadan, Nigeria
| | - Jochen M. Schwenk
- SciLifeLab Stockholm, School of Biotechnology, KTH-Royal Institute of Technology, Stockholm, Sweden
| | - Mats Wahlgren
- Department of Microbiology, Tumour and Cell Biology, Karolinska Institutet, Stockholm, Sweden
- * E-mail: (MW); (DFR); (PN)
| | - Delmiro Fernandez-Reyes
- Division of Parasitology, Medical Research Council National Institute for Medical Research, London, United Kingdom
- Department of Paediatrics, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
- Department of Haematology, College of Medicine, University of Ibadan, University College Hospital, Ibadan, Nigeria
- Childhood Malaria Research Group, University College Hospital, Ibadan, Nigeria
- Brighton & Sussex Medical School, Sussex University, Brighton, United Kingdom
- * E-mail: (MW); (DFR); (PN)
| | - Peter Nilsson
- SciLifeLab Stockholm, School of Biotechnology, KTH-Royal Institute of Technology, Stockholm, Sweden
- * E-mail: (MW); (DFR); (PN)
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97
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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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98
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El-Assaad F, Wheway J, Hunt NH, Grau GER, Combes V. Production, fate and pathogenicity of plasma microparticles in murine cerebral malaria. PLoS Pathog 2014; 10:e1003839. [PMID: 24651155 PMCID: PMC3961352 DOI: 10.1371/journal.ppat.1003839] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 11/04/2013] [Indexed: 11/23/2022] Open
Abstract
In patients with cerebral malaria (CM), higher levels of cell-specific microparticles (MP) correlate with the presence of neurological symptoms. MP are submicron plasma membrane-derived vesicles that express antigens of their cell of origin and phosphatidylserine (PS) on their surface, facilitating their role in coagulation, inflammation and cell adhesion. In this study, the in vivo production, fate and pathogenicity of cell-specific MP during Plasmodium berghei infection of mice were evaluated. Using annexin V, a PS ligand, and flow cytometry, analysis of platelet-free plasma from infected mice with cerebral involvement showed a peak of MP levels at the time of the neurological onset. Phenotypic analyses showed that MP from infected mice were predominantly of platelet, endothelial and erythrocytic origins. To determine the in vivo fate of MP, we adoptively transferred fluorescently labelled MP from mice with CM into healthy or infected recipient mice. MP were quickly cleared following intravenous injection, but microscopic examination revealed arrested MP lining the endothelium of brain vessels of infected, but not healthy, recipient mice. To determine the pathogenicity of MP, we transferred MP from activated endothelial cells into healthy recipient mice and this induced CM-like brain and lung pathology. This study supports a pathogenic role for MP in the aggravation of the neurological lesion and suggests a causal relationship between MP and the development of CM. Cerebral malaria (CM) is a potentially fatal neurological syndrome characterised by unrousable coma. Since the detection of high levels of plasma microparticles (MP) in patients with CM, it has been demonstrated that inhibition of MP production confers protection from murine CM. However, the precise mechanisms of action of these MP during CM have not been completely deciphered. In this study, we used experimental models of CM to measure the production and origins of MP over the course of infection. We found low baseline circulating MP in healthy mice and these were subsequently raised at the time of the neurological syndrome. Phenotypic analyses showed that circulating MP were predominantly from activated host cells that have previously been established to participate in CM pathogenesis. We show for the first time transferred MP impairing endothelial integrity and inducing CM-like pathology in the brain and lung of healthy animals. Our study dissects what tissues these MP localise to exert their effects, as little is known about their fate following the initial release. These data suggest a causal relationship between MP and the development of CM and also warrant further investigation into the representation of MP as a marker of CM risk.
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Affiliation(s)
- Fatima El-Assaad
- Vascular Immunology Unit, Department of Pathology, Sydney Medical School, The University of Sydney, Sydney, Australia
| | - Julie Wheway
- Vascular Immunology Unit, Department of Pathology, Sydney Medical School, The University of Sydney, Sydney, Australia
| | - Nicholas H. Hunt
- Molecular Immunopathology Unit, Department of Pathology, Sydney Medical School, The University of Sydney, Sydney, Australia
| | - Georges E. R. Grau
- Vascular Immunology Unit, Department of Pathology, Sydney Medical School, The University of Sydney, Sydney, Australia
| | - Valery Combes
- Vascular Immunology Unit, Department of Pathology, Sydney Medical School, The University of Sydney, Sydney, Australia
- * E-mail:
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99
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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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Adukpo S, Kusi KA, Ofori MF, Tetteh JKA, Amoako-Sakyi D, Goka BQ, Adjei GO, Edoh DA, Akanmori BD, Gyan BA, Dodoo D. High plasma levels of soluble intercellular adhesion molecule (ICAM)-1 are associated with cerebral malaria. PLoS One 2013; 8:e84181. [PMID: 24386348 PMCID: PMC3873986 DOI: 10.1371/journal.pone.0084181] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 11/12/2013] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Cerebral malaria (CM) is responsible for most of the malaria-related deaths in children in sub-Saharan Africa. Although, not well understood, the pathogenesis of CM involves parasite and host factors which contribute to parasite sequestration through cytoadherence to the vascular endothelium. Cytoadherence to brain microvasculature is believed to involve host endothelial receptor, CD54 or intercellular adhesion molecule (ICAM)-1, while other receptors such as CD36 are generally involved in cytoadherence of parasites in other organs. We therefore investigated the contributions of host ICAM-1 expression and levels of antibodies against ICAM-1 binding variant surface antigen (VSA) on parasites to the development of CM. METHODOLOGY/PRINCIPAL FINDINGS Paediatric malaria patients, 0.5 to 13 years were recruited and grouped into CM and uncomplicated malaria (UM) patients, based on well defined criteria. Standardized ELISA protocol was used to measure soluble ICAM-1 (sICAM-1) levels from acute plasma samples. Levels of IgG to CD36- or ICAM-1-binding VSA were measured by flow cytometry during acute and convalescent states. Wilcoxon sign rank-test analysis to compare groups revealed association between sICAM-1 levels and CM (p<0.0037). Median levels of antibodies to CD36-binding VSA were comparable in the two groups at the time of admission and 7 days after treatment was initiated (p>0.05). Median levels of antibodies to CD36-binding VSAs were also comparable between acute and convalescent samples within any patient group. Median levels of antibodies to ICAM-1-binding VSAs were however significantly lower at admission time than during recovery in both groups. CONCLUSIONS/SIGNIFICANCE High levels of sICAM-1 were associated with CM, and the sICAM-1 levels may reflect expression levels of the membrane bound form. Anti-VSA antibody levels to ICAM-binding parasites was more strongly associated with both UM and CM than antibodies to CD36 binding parasites. Thus, increasing host sICAM-1 levels were associated with CM whilst antibodies to parasite expressing non-ICAM-1-binding VSAs were not.
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Affiliation(s)
- Selorme Adukpo
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
- Department of Animal Biology and Conservation Science, University of Ghana, Legon, Accra, Ghana
- * E-mail:
| | - Kwadwo A. Kusi
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Michael F. Ofori
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - John K. A. Tetteh
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Daniel Amoako-Sakyi
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Bamenla Q. Goka
- Department of Child Health, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - George O. Adjei
- Department of Child Health, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Dominic A. Edoh
- Department of Animal Biology and Conservation Science, University of Ghana, Legon, Accra, Ghana
| | - Bartholomew D. Akanmori
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Ben A. Gyan
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
| | - Daniel Dodoo
- Immunology Department, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Legon, Accra, Ghana
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