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Chaudhary A, Kataria P, Surela N, Das J. Pathophysiology of Cerebral Malaria: Implications of MSCs as A Regenerative Medicinal Tool. Bioengineering (Basel) 2022; 9:bioengineering9060263. [PMID: 35735506 PMCID: PMC9219920 DOI: 10.3390/bioengineering9060263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/02/2022] [Accepted: 05/03/2022] [Indexed: 11/16/2022] Open
Abstract
The severe form of malaria, i.e., cerebral malaria caused by Plasmodium falciparum, is a complex neurological syndrome. Surviving persons have a risk of behavioral difficulties, cognitive disorders, and epilepsy. Cerebral malaria is associated with multiple organ dysfunctions. The adhesion and accumulation of infected RBCs, platelets, and leucocytes (macrophages, CD4+ and CD8+ T cells, and monocytes) in the brain microvessels play an essential role in disease progression. Micro-vascular hindrance by coagulation and endothelial dysfunction contributes to neurological damage and the severity of the disease. Recent studies in human cerebral malaria and the murine model of cerebral malaria indicate that different pathogens as well as host-derived factors are involved in brain microvessel adhesion and coagulation that induces changes in vascular permeability and impairment of the blood-brain barrier. Efforts to alleviate blood-brain barrier dysfunction and de-sequestering of RBCs could serve as adjunct therapies. In this review, we briefly summarize the current understanding of the pathogenesis of cerebral malaria, the role of some factors (NK cells, platelet, ANG-2/ANG-1 ratio, and PfEMP1) in disease progression and various functions of Mesenchymal stem cells. This review also highlighted the implications of MSCs as a regenerative medicine.
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Affiliation(s)
- Amrendra Chaudhary
- Parasite-Host Biology, National Institute of Malaria Research, New Delhi 110077, India; (A.C.); (P.K.); (N.S.)
| | - Poonam Kataria
- Parasite-Host Biology, National Institute of Malaria Research, New Delhi 110077, India; (A.C.); (P.K.); (N.S.)
| | - Neha Surela
- Parasite-Host Biology, National Institute of Malaria Research, New Delhi 110077, India; (A.C.); (P.K.); (N.S.)
| | - Jyoti Das
- Parasite-Host Biology, National Institute of Malaria Research, New Delhi 110077, India; (A.C.); (P.K.); (N.S.)
- AcSIR, Ghaziabad 201002, India
- Correspondence: or ; Tel.: +91-25307203; Fax: +91-25307177
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Wassmer SC, Grau GER, MacCormick IJC. Bridging and Clumping: Investigating Platelet Interactions with P. falciparum-Infected Red Blood Cells and Endothelial Cells in Cerebral Malaria. Methods Mol Biol 2022; 2470:505-514. [PMID: 35881370 DOI: 10.1007/978-1-0716-2189-9_38] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The methods presented in this chapter describe how to perform ex vivo clumping and in vitro bridging assays in the context of cerebral malaria. Both the protocols are detailed, and emphasis is made on how to prepare platelet suspensions suitable to each technique, including description of specific buffers and reagents to minimize the risk of aggregation while maintaining the platelet properties.
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Affiliation(s)
| | - Georges Emile Raymond Grau
- Vascular Immunology Unit, School of Medical Sciences, The University of Sydney, Camperdown, NSW, Australia
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3
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Kömpf D, Held J, Müller SF, Drechsel HR, Tschan SC, Northoff H, Mordmüller B, Gehring FK. Real-time measurement of Plasmodium falciparum-infected erythrocyte cytoadhesion with a quartz crystal microbalance. Malar J 2016; 15:317. [PMID: 27296675 PMCID: PMC4906606 DOI: 10.1186/s12936-016-1374-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 06/04/2016] [Indexed: 11/13/2022] Open
Abstract
Background An important virulence mechanism of the malaria parasite Plasmodium falciparum is cytoadhesion, the binding of infected erythrocytes to endothelial cells in the second half of asexual blood stage development. Conventional methods to investigate adhesion of infected erythrocytes are mostly performed under static conditions, many are based on manual or semi-automated read-outs and are, therefore, difficult to standardize. Quartz crystal microbalances (QCM) are sensitive to nanogram-scale changes in mass and biomechanical properties and are increasingly used in biomedical research. Here, the ability of QCM is explored to measure binding of P. falciparum-infected erythrocytes to two receptors: CD36 and chondroitin sulfate A (CSA) under flow conditions. Methods Binding of late stage P. falciparum parasites is measured in comparison to uninfected erythrocytes to CD36- and CSA-coated quartzes by QCM observing frequency shifts. CD36-expressing cell membrane fragments and CSA polysaccharide were coated via poly-l-lysine to the quartz. The method was validated by microscopic counting of attached parasites and of erythrocytes to the coated quartzes. Results Frequency shifts indicating binding of infected erythrocytes could be observed for both receptors CD36 and CSA. The frequency shifts seen for infected and uninfected erythrocytes were strongly correlated to the microscopically counted numbers of attached cells. Conclusions In this proof-of-concept experiment it is shown that QCM is a promising tool to measure binding kinetics and specificity of ligand-receptor interactions using viable, parasite-infected erythrocytes. The method can improve the understanding of the virulence of P. falciparum and might be used to cross-validate other methods. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1374-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniela Kömpf
- Biosensor Research Group, Institute of Clinical and Experimental Transfusion Medicine, University Hospital of Tübingen, Tübingen, Germany.,State Health Office Baden-Württemberg, Stuttgart, Germany
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany. .,DZIF-Deutsches Zentrum für Infektionsforschung, Standort Tübingen, Germany.
| | - Stefani F Müller
- Biosensor Research Group, Institute of Clinical and Experimental Transfusion Medicine, University Hospital of Tübingen, Tübingen, Germany
| | - Hartmut R Drechsel
- Biosensor Research Group, Institute of Clinical and Experimental Transfusion Medicine, University Hospital of Tübingen, Tübingen, Germany.,3T GmbH & Co KG, Tuttlingen, Germany
| | - Serena C Tschan
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,DZIF-Deutsches Zentrum für Infektionsforschung, Standort Tübingen, Germany
| | - Hinnak Northoff
- Biosensor Research Group, Institute of Clinical and Experimental Transfusion Medicine, University Hospital of Tübingen, Tübingen, Germany
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,DZIF-Deutsches Zentrum für Infektionsforschung, Standort Tübingen, Germany
| | - Frank K Gehring
- Biosensor Research Group, Institute of Clinical and Experimental Transfusion Medicine, University Hospital of Tübingen, Tübingen, Germany. .,3T GmbH & Co KG, Tuttlingen, Germany.
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4
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Evaluation of a novel magneto-optical method for the detection of malaria parasites. PLoS One 2014; 9:e96981. [PMID: 24824542 PMCID: PMC4019541 DOI: 10.1371/journal.pone.0096981] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 04/15/2014] [Indexed: 11/19/2022] Open
Abstract
Improving the efficiency of malaria diagnosis is one of the main goals of current malaria research. We have recently developed a magneto-optical (MO) method which allows high-sensitivity detection of malaria pigment (hemozoin crystals) in blood via the magnetically induced rotational motion of the hemozoin crystals. Here, we evaluate this MO technique for the detection of Plasmodium falciparum in infected erythrocytes using in-vitro parasite cultures covering the entire intraerythrocytic life cycle. Our novel method detected parasite densities as low as ∼ 40 parasites per microliter of blood (0.0008% parasitemia) at the ring stage and less than 10 parasites/µL (0.0002% parasitemia) in the case of the later stages. These limits of detection, corresponding to approximately 20 pg/µL of hemozoin produced by the parasites, exceed that of rapid diagnostic tests and compete with the threshold achievable by light microscopic observation of blood smears. The MO diagnosis requires no special training of the operator or specific reagents for parasite detection, except for an inexpensive lysis solution to release intracellular hemozoin. The devices can be designed to a portable format for clinical and in-field tests. Besides testing its diagnostic performance, we also applied the MO technique to investigate the change in hemozoin concentration during parasite maturation. Our preliminary data indicate that this method may offer an efficient tool to determine the amount of hemozoin produced by the different parasite stages in synchronized cultures. Hence, it could eventually be used for testing the susceptibility of parasites to antimalarial drugs.
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Eckhoff P. P. falciparum infection durations and infectiousness are shaped by antigenic variation and innate and adaptive host immunity in a mathematical model. PLoS One 2012; 7:e44950. [PMID: 23028698 PMCID: PMC3446976 DOI: 10.1371/journal.pone.0044950] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 08/14/2012] [Indexed: 11/29/2022] Open
Abstract
Many questions remain about P. falciparum within-host dynamics, immunity, and transmission–issues that may affect public health campaign planning. These gaps in knowledge concern the distribution of durations of malaria infections, determination of peak parasitemia during acute infection, the relationships among gametocytes and immune responses and infectiousness to mosquitoes, and the effect of antigenic structure on reinfection outcomes. The present model of intra-host dynamics of P. falciparum implements detailed representations of parasite and immune dynamics, with structures based on minimal extrapolations from first-principles biology in its foundations. The model is designed to quickly and readily accommodate gains in mechanistic understanding and to evaluate effects of alternative biological hypothesis through in silico experiments. Simulations follow the parasite from the liver-stage through the detailed asexual cycle to clearance while tracking gametocyte populations. The modeled immune system includes innate inflammatory and specific antibody responses to a repertoire of antigens. The mechanistic focus provides clear explanations for the structure of the distribution of infection durations through the interaction of antigenic variation and innate and adaptive immunity. Infectiousness to mosquitoes appears to be determined not only by the density of gametocytes but also by the level of inflammatory cytokines, which harmonizes an extensive series of study results. Finally, pre-existing immunity can either decrease or increase the duration of infections upon reinfection, depending on the degree of overlap in antigenic repertoires and the strength of the pre-existing immunity.
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Affiliation(s)
- Philip Eckhoff
- Intellectual Ventures, Bellevue, Washington, United States of America.
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Volz J, Bártfai R, Petter M, Langer C, Josling G, Tsuboi T, Schwach F, Baum J, Rayner J, Stunnenberg H, Duffy M, Cowman A. PfSET10, a Plasmodium falciparum Methyltransferase, Maintains the Active var Gene in a Poised State during Parasite Division. Cell Host Microbe 2012; 11:7-18. [DOI: 10.1016/j.chom.2011.11.011] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Revised: 10/27/2011] [Accepted: 11/30/2011] [Indexed: 11/25/2022]
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7
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Bernabeu M, Lopez FJ, Ferrer M, Martin-Jaular L, Razaname A, Corradin G, Maier AG, Del Portillo HA, Fernandez-Becerra C. Functional analysis of Plasmodium vivax VIR proteins reveals different subcellular localizations and cytoadherence to the ICAM-1 endothelial receptor. Cell Microbiol 2011; 14:386-400. [PMID: 22103402 DOI: 10.1111/j.1462-5822.2011.01726.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The subcellular localization and function of variant subtelomeric multigene families in Plasmodium vivax remain vastly unknown. Among them, the vir superfamily is putatively involved in antigenic variation and in mediating adherence to endothelial receptors. In the absence of a continuous in vitro culture system for P. vivax, we have generated P. falciparum transgenic lines expressing VIR proteins to infer location and function. We chose three proteins pertaining to subfamilies A (VIR17), C (VIR14) and D (VIR10), with domains and secondary structures that predictably traffic these proteins to different subcellular compartments. Here, we showed that VIR17 remained inside the parasite and around merozoites, whereas VIR14 and VIR10 were exported to the membrane of infected red blood cells (iRBCs) in an apparent independent pathway of Maurer's clefts. Remarkably, VIR14 was exposed at the surface of iRBCs and mediated adherence to different endothelial receptors expressed in CHO cells under static conditions. Under physiological flow conditions, however, cytoadherence was only observed to ICAM-1, which was the only receptor whose adherence was specifically and significantly inhibited by antibodies against conserved motifs of VIR proteins. Immunofluorescence studies using these antibodies also showed different subcellular localizations of VIR proteins in P. vivax-infected reticulocytes from natural infections. These data suggest that VIR proteins are trafficked to different cellular compartments and functionally demonstrates that VIR proteins can specifically mediate cytoadherence to the ICAM-1 endothelial receptor.
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Affiliation(s)
- M Bernabeu
- Barcelona Centre for International Health Research (CRESIB, Hospital Clínic-Universitat de Barcelona), Barcelona, Spain
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8
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Wassmer SC, Combes V, Grau GE. Platelets and microparticles in cerebral malaria: the unusual suspects. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.ddmec.2011.11.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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9
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Margination of red blood cells infected by Plasmodium falciparum in a microvessel. J Biomech 2011; 44:1553-8. [PMID: 21420683 DOI: 10.1016/j.jbiomech.2011.02.084] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 02/24/2011] [Accepted: 02/25/2011] [Indexed: 11/23/2022]
Abstract
We investigated numerically the mechanism of margination of Plasmodium falciparum malaria-infected red blood cells (Pf-IRBCs) in micro-scale blood flow. Our model illustrates that continuous hydrodynamic interaction between a Pf-IRBC in the trophozoite stage (Pf-T-IRBC) and healthy red blood cells (HRBCs) results in the margination of the Pf-T-IRBC and, thus, a longer duration of contact with endothelial cells. The Pf-T-IRBC and HRBCs first form a "train". The volume fraction of RBCs is then locally increased, to approximately 40%, and this value is maintained for a long period of time due to the formation of a long train in high-hematocrit conditions. Even in low-hematocrit conditions, the local volume fraction is instantaneously elevated to 40% and the Pf-T-IRBC can migrate to the wall. However, the short train formed in low-hematocrit conditions does not provide continuous interaction, and the Pf-T-IRBC moves back to the center of the channel.
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Karl S, Davis TME, St Pierre TG. Parameterization of high magnetic field gradient fractionation columns for applications with Plasmodium falciparum infected human erythrocytes. Malar J 2010; 9:116. [PMID: 20433771 PMCID: PMC2877061 DOI: 10.1186/1475-2875-9-116] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2009] [Accepted: 05/03/2010] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Magnetic fractionation of erythrocytes infected with Plasmodium falciparum has several research uses including enrichment of infected cells from parasite cultures or enhanced detection of P. falciparum gametocytes. The aim of the present study was to quantitatively characterize the magnetic fractionation process and thus enable optimization of protocols developed for specific uses. METHODS Synchronized cultures of P. falciparum parasites incubated with human erythrocytes were magnetically fractionated with commercially available columns. The timing of the fractionation experiments was such that the parasites were in second half of their erythrocytic life cycle with parasite densities ranging from 1 to 9%. Fractionations were carried out in a single pass through the columns. Cells were enumerated and differentiated in the initial samples as well as in the positive and negative fractions. The capture of cells by the fractionation column was described by a saturation binding model. RESULTS The magnetic binding affinity to the column matrix was approximately 350 times greater for infected cells compared with uninfected cells. The purity of infected cells in the captured fraction was generally >80% but decreased rapidly (to less than 50%) when the number of infected cells that passed through the column was substantially decreased (to less than 9 +/- 5 x 105 cells). The distribution of captured parasite developmental stages shifted to mature stages as the number of infected cells in the initial samples and flow rate increased. The relationship between the yield of infected cells in the captured fraction and flow rate of cells conformed to a complementary cumulative log-normal equation with flow rates >1.6 x 105 cells per second resulting in yields <50%. CONCLUSIONS A detailed quantitative analysis of a batchwise magnetic fractionation process for malaria infected erythrocytes using high gradient magnetic fractionation columns was performed. The models applied in this study allow the prediction of capture efficiency if the initial infected cell concentration and the flow rate are known.
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Affiliation(s)
- Stephan Karl
- School of Physics, M013, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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11
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Costa FTM, Avril M, Nogueira PA, Gysin J. Cytoadhesion of Plasmodium falciparum-infected erythrocytes and the infected placenta: a two-way pathway. Braz J Med Biol Res 2007; 39:1525-36. [PMID: 17160261 DOI: 10.1590/s0100-879x2006001200003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Accepted: 08/18/2006] [Indexed: 11/21/2022] Open
Abstract
Malaria is undoubtedly the world's most devastating parasitic disease, affecting 300 to 500 million people every year. Some cases of Plasmodium falciparum infection progress to the deadly forms of the disease responsible for 1 to 3 million deaths annually. P. falciparum-infected erythrocytes adhere to host receptors in the deep microvasculature of several organs. The cytoadhesion of infected erythrocytes to placental syncytiotrophoblast receptors leads to pregnancy-associated malaria (PAM). This specific maternal-fetal syndrome causes maternal anemia, low birth weight and the death of 62,000 to 363,000 infants per year in sub-Saharan Africa, and thus has a poor outcome for both mother and fetus. However, PAM and non-PAM parasites have been shown to differ antigenically and genetically. After multiple pregnancies, women from different geographical areas develop adhesion-blocking antibodies that protect against placental parasitemia and clinical symptoms of PAM. The recent description of a new parasite ligand encoded by the var2CSA gene as the only gene up-regulated in PAM parasites renders the development of an anti-PAM vaccine more feasible. The search for a vaccine to prevent P. falciparum sequestration in the placenta by eliciting adhesion-blocking antibodies and a cellular immune response, and the development of new methods for evaluating such antibodies should be key priorities in mother-child health programs in areas of endemic malaria. This review summarizes the main molecular, immunological and physiopathological aspects of PAM, including findings related to new targets in the P. falciparum var gene family. Finally, we focus on a new methodology for mimicking cytoadhesion under blood flow conditions in human placental tissue.
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MESH Headings
- Animals
- Antibodies, Protozoan/blood
- Antibodies, Protozoan/immunology
- Antigens, Protozoan/blood
- Antigens, Protozoan/drug effects
- Antigens, Protozoan/genetics
- Antigens, Protozoan/immunology
- Cell Adhesion/physiology
- Erythrocytes/immunology
- Erythrocytes/parasitology
- Female
- Humans
- Malaria Vaccines
- Malaria, Falciparum/blood
- Malaria, Falciparum/immunology
- Placenta/parasitology
- Plasmodium falciparum/genetics
- Plasmodium falciparum/immunology
- Plasmodium falciparum/physiology
- Pregnancy
- Pregnancy Complications, Parasitic/blood
- Pregnancy Complications, Parasitic/immunology
- Protozoan Proteins/blood
- Protozoan Proteins/drug effects
- Protozoan Proteins/immunology
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Affiliation(s)
- F T M Costa
- Departamento de Microbiologia e Imunologia, Instituto de Biologia, Universidade Estadual de Campinas, 13083-862 Campinas, SP, Brazil.
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12
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Hutchings CL, Li A, Fernandez KM, Fletcher T, Jackson LA, Molloy JB, Jorgensen WK, Lim CT, Cooke BM. New insights into the altered adhesive and mechanical properties of red blood cells parasitized by Babesia bovis. Mol Microbiol 2007; 65:1092-105. [PMID: 17640278 DOI: 10.1111/j.1365-2958.2007.05850.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Sequestration of parasite-infected red blood cells (RBCs) in the microvasculature is an important pathological feature of both bovine babesiosis caused by Babesia bovis and human malaria caused by Plasmodium falciparum. Surprisingly, when compared with malaria, the cellular and molecular mechanisms that underlie this abnormal circulatory behaviour for RBCs infected with B. bovis have been relatively ignored. Here, we present some novel insights into the adhesive and mechanical changes that occur in B. bovis-infected bovine RBCs and compare them with the alterations that occur in human RBCs infected with P. falciparum. After infection with B. bovis, bovine RBCs become rigid and adhere to vascular endothelial cells under conditions of physiologically relevant flow. These alterations are accompanied by the appearance of ridge-like structures on the RBC surface that are analogous, but morphologically and biochemically different, to the knob-like structures on the surface of human RBCs infected with P. falciparum. Importantly, albeit for a limited number of parasite lines examined here, the extent of these cellular and rheological changes appear to be related to parasite virulence. Future investigations to identify the precise molecular composition of ridges and the proteins that mediate adhesion will provide important insight into the pathogenesis of both babesiosis and malaria.
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13
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Anniss AM, Sparrow RL. Variable adhesion of different red blood cell products to activated vascular endothelium under flow conditions. Am J Hematol 2007; 82:439-45. [PMID: 17133424 DOI: 10.1002/ajh.20837] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Red blood cells (RBCs) that have been stored prior to transfusion show increased adherence to vascular endothelium in vitro, which suggests a potential for stored blood transfusion to impede blood flow in some patients. Transfusion is often required in patients with sepsis or inflammation; however, whether activation of endothelium affects stored RBC-endothelial cell (EC) interactions is unknown. We investigated whether storage time and leukocyte content of RBC products influences the adhesion of RBCs to activated ECs. RBCs from nonleukocyte-reduced (S-RBCs), buffy-coat-poor (BCP-RBCs), and leukocyte-filtered (LF-RBCs) products and cultured EC layers were pretreated with endotoxin, tumor necrosis factor-alpha (TNF-alpha), or medium alone prior to perfusion of the RBCs across the EC layer in a continuous flow microchamber. After a single day of RBC storage, the number of adherent RBCs was increased in the endotoxin and TNF-alpha pretreated groups compared to the unactivated-control group. These differences were statistically significant for S-RBCs and LF-RBC products (P < 0.05). In contrast, there was no significant difference in RBC adherence to activated and unactivated endothelium at other time-points of RBC product storage. The strength of adhesion of stored RBCs from S-RBC products to activated ECs was not altered following treatment; however, endotoxin significantly increased the adhesive strength of LF-RBCs to endothelium. These results demonstrate that while fresh RBCs show increased adhesion to activated endothelium, storage of RBCs did not promote increased adhesion to activated endothelium. However, inflammatory conditions promote stronger adhesion of stored RBCs to ECs, which may contribute to impaired tissue perfusion in some transfusion recipients.
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Affiliation(s)
- Angela M Anniss
- Australian Red Cross Blood Service, Research Unit, Balston Street, Southbank, Victoria, Australia
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14
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Bhadra D, Bhadra S, Jain NK. PEGylated Peptide Dendrimeric Carriers for the Delivery of Antimalarial Drug Chloroquine Phosphate. Pharm Res 2006; 23:623-33. [PMID: 16374532 DOI: 10.1007/s11095-005-9396-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2005] [Accepted: 11/03/2005] [Indexed: 11/27/2022]
Abstract
PURPOSE The present study was aimed at developing and exploring the use of uncoated and chondroitin sulfate A (CSA) coated PEGylated poly-L-lysine-based dendrimers for controlled and sustained delivery of a blood schizonticide, chloroquine phosphate (CQ). METHODS The poly-L-lysine-based peptide dendrimers with PEG amine core prepared and coated with CSA were used to encapsulate the drug molecules by dialysis method. Effect of CSA coating on the surface characteristics, drug entrapment, drug release, stability, hemolytic toxicity, macrophageal interactions, and cytoadherence were determined and compared with those of uncoated systems. RESULTS The CSA coating of the carriers was found to increase size and drug loading capacity, and reduce drug release rate and hemolytic toxicity. Transmission electron microscopic study revealed the surface properties of the systems. Stability studies had shown increased stability of the formulations on CSA coating. There was a significant reduction in hemolytic toxicity and cytotoxicity of CQ by the present dendrimeric carriers, which became more prominent on further CSA conjugation of the equivalent drug-loaded dendrimeric carriers. There were also significant reduction in levels of ring and trophozoite stages of Plasmodium falciparum in liquid culture when treated with CSA coated dendrimers because of the expression of similar carbohydrate receptors as that by placental and cerebral barriers for infected red blood cells. The systems were also found suitable for prolonging and controlling the blood level of drug as indicated by blood level and organ distribution studies in albino rats on intravenous administration, precluding any significant hematological or toxicological manifestations. CONCLUSION Thus it can be said that CSA coating can improve drug-loading capacity, control and sustain the release of CQ from such carriers, and can suitably act as safer and effective carriers for intravenous CQ administration.
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Affiliation(s)
- D Bhadra
- Pharmaceutics Research Laboratory, Department of Pharmaceutical Sciences, Dr. H.S. Gour University, Sagar (MP), 470003, India
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15
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Cooke BM, Mohandas N, Cowman AF, Coppel RL. Cellular adhesive phenomena in apicomplexan parasites of red blood cells. Vet Parasitol 2005; 132:273-95. [PMID: 16087297 DOI: 10.1016/j.vetpar.2005.07.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The apicomplexan parasites Babesia and Plasmodium are related, yet phylogenetically distinct haemoprotozoa that infect red blood cells and cause severe diseases of major human and veterinary importance. A variety of cellular and molecular interactions are pivotal in many aspects of the pathogenicity of these two parasites. Comparison of the cellular and molecular mechanisms that culminate in accumulation of parasitised red blood cells in the microvasculature of cattle infected with Babesia bovis (babesiosis) and humans infected with Plasmodium falciparum (falciparum malaria) is particularly instructive given the striking similarities in the pathophysiology of these two important medical and veterinary diseases. While such adhesive phenomena have been studied extensively in malaria, they have received relatively little attention in babesiosis. In this review, we summarise the findings of more than 25 years of research into cellular adhesive phenomena in malaria and speculate on how this body of work can now be applied to Babesia parasites. Such information is fundamental if we are to learn more about the biology of Babesia parasites, the cellular and molecular mechanisms by which they cause infection and disease and how to develop novel therapeutic strategies or vaccines for both Babesia and malaria infections.
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Affiliation(s)
- Brian M Cooke
- Department of Microbiology, Monash University, Vic. 3800, Australia.
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16
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Rogerson SJ, Brown GV. Chondroitin sulphate A as an adherence receptor for Plasmodium falciparum-infected erythrocytes. ACTA ACUST UNITED AC 2005; 13:70-5. [PMID: 15275126 DOI: 10.1016/s0169-4758(96)10081-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Until recently, the sequestration of erythrocytes infected with Plasmodium falciparum has been thought to be due to one of a number of protein-protein interactions. In this article, Stephen Rogerson and Graham Brown summarize the emerging evidence that, in vitro, infected erythrocytes can also adhere to the glycosaminoglycan chondroitin sulphate A (CSA) expressed on the surface of cells and immobilized on plastic. In vivo, binding of infected erythrocytes to CSA could be crucial to the development of malarial infection of the placenta, and possibly to sequestration in the lung and brain. The consequences of this may include maternal morbidity and mortality, low birth weight in the infant, pulmonary oedema and cerebral malaria. They discuss the need to characterize the molecular basis of this interaction, and to investigate the possible therapeutic role of CSA in malaria. Chondroitin sulphates are nontoxic compounds already in use for other diseases in humans. Vaccines based on inhibiting this receptor-ligand interaction could also be appropriate.
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Affiliation(s)
- S J Rogerson
- Immunoparasitology Unit. The Walter and Eliza Hall Institute of Medical Research, Post Office Royal Melbourne Hospital, Victoria 3050, Australia.
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17
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18
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Bhadra D, Bhadra S, Jain N. PEGylated peptide-based dendritic nanoparticulate systems for delivery of artemether. J Drug Deliv Sci Technol 2005. [DOI: 10.1016/s1773-2247(05)50008-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Abstract
Malaria is the most serious and widespread parasitic disease of humans and is arguably the commonest disease of red blood cells (RBCs). Malaria has exerted a powerful effect on human evolution and selection for resistance has led to the appearance and persistence of a number of inherited diseases. After parasite invasion, RBCs are progressively and dramatically modified. New structures appear inside the RBC and novel parasite proteins are exported to the erythrocyte cytoplasm and membrane skeleton. Radical biochemical, morphological, and rheological alterations manifest as increased membrane rigidity, reduced cell deformability, and greater adhesiveness for the vascular endothelium and other blood cells. Numerous protein-protein interactions between the malaria-parasite and the host RBC are important for many aspects of parasite biology and the pathogenesis of malaria. In addition, there are many other parasite proteins located within the infected red cell and at the membrane skeleton, for which no precise functional roles have yet been elucidated. Sequencing and annotation of the complete genome of Plasmodium falciparum, the production of proteomic and transcriptomic profiles of parasites, and the development of a transfection system for the asexual stage of the parasite are all recent achievements that should advance understanding of the molecular mechanisms that underlie the parasite-induced functional alterations in red cells.
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Affiliation(s)
- Brian M Cooke
- Department of Microbiology, Monash University, Victoria 3800, Australia
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Eichelbrönner O, Sibbald WJ, Chin-Yee IH. Intermittent flow increases endotoxin-induced adhesion of human erythrocytes to vascular endothelial cells. Intensive Care Med 2003; 29:709-14. [PMID: 12632262 DOI: 10.1007/s00134-003-1698-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2002] [Accepted: 01/27/2003] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To investigate the effects of different conditions of flow on endotoxin induced adhesion of human red blood cells (RBC) to human umbilical vein endothelial cells (HUVEC). DESIGN AND SETTING Prospective, randomized, controlled in vitro study in a university-affiliated cell biology laboratory. SUBJECTS. Human erythrocytes, human vascular endothelial cells. INTERVENTIONS Superfusion of HUVEC monolayers with human erythrocytes incubated with either saline (CON) or endotoxin (ETX) with different flow pattern (basic flow rates of 0.65 or 1.3 ml/min; intermittent flow, IMF). The CON/0.6, CON/1.3, CON-IMF/1.3 ( n=7/group) groups served as control, and in test groups ETX/0.6, ETX/1.3, ETX-IMF/0.6, and ETX-IMF/1.3 ( n=7/group) both RBC and HUVECs were incubated with ETX and flow pattern and rates varied. In the IMF experiments flow rates of 0.65 and 1.3 ml/min were combined with stop-and-go flow pattern. MEASUREMENTS AND RESULTS At continuous flow of 0.65 ml/min erythrocyte adhesion was 61+/-5 cells/mm(2) in CON and 172+/-25 cells/mm(2) after ETX. When flow rate was increased to 1.3 ml/min, adhesion decreased to 27+/-4 cells/mm(2) in CON and 93+/-18 cells/mm(2) after ETX. IMF conditions had no effect on RBC adhesion of naive RBC but increased the number of adhesive erythrocytes after incubation with ETX both at 0.65 ml/min (287+/-33 cells/mm(2)) and at 1.3 ml/min (148+/-13 cells/mm(2)). CONCLUSIONS RBC adhesion to vascular endothelium is affected by rate and pattern of blood flow. Higher flow rates or shear forces reduce RBC adhesion while stop-and-go flow pattern favored adhesion of ETX-treated erythrocytes to HUVECs. These findings suggest that altered RBCs interact with altered flow patterns potentially contributing to the microcirculatory injury observed in sepsis.
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Affiliation(s)
- Otto Eichelbrönner
- A.C. Burton Vascular Biology Laboratory, London Health Sciences Centre, University of Western Ontario, 800 Commissoners Road East, London, Ontario N6A 4G5, Canada
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21
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Molloy JB, Bowles PM, Jorgensen WK, Cooke BM. Babesia bovis: adhesion of parasitized red blood cells to bovine umbilical vein endothelial cells in vitro does not select for virulence. Exp Parasitol 2003; 103:182-4. [PMID: 12880598 DOI: 10.1016/s0014-4894(03)00095-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- John B Molloy
- Department of Primary Industries-Queensland, Agency for Food and Fibre Sciences, 665 Fairfield Road, Yeerongpilly, Queensland 4105, Australia.
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22
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Luk CS, Gray-Statchuk LA, Cepinkas G, Chin-Yee IH. WBC reduction reduces storage-associated RBC adhesion to human vascular endothelial cells under conditions of continuous flow in vitro. Transfusion 2003; 43:151-6. [PMID: 12559009 DOI: 10.1046/j.1537-2995.2003.00310.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The effects of storage duration, WBC reduction, and irradiation on RBC adherence to vascular endothelia are unknown and are investigated under conditions of continuous flow. STUDY DESIGN AND METHODS Thirty-two RBC units were collected and divided into three groups, non-WBC-reduced (NWR), WBC-reduced (WR), and irradiated-WBC-reduced. Aliquots of RBCs were removed on Days 1, 15, and 28 of storage for analysis. The RBC suspensions were then perfused at a 1.5 percent Hct in a protein-poor medium under conditions of continuous flow over human umbilical vein endothelial cell monolayers. On each slide, 25 randomly chosen sites were videorecorded over 10 minutes, and the number of RBCs adherent to the endothelial cell monolayer was counted. RESULTS NWR RBCs stored for 28 days demonstrated a greater degree of adherence to endothelial cells compared to Days 1 and 15 (p < 0.03). The WR group had significantly fewer adherent RBCs than the NWR group on day 28 (p < 0.01). Irradiation had no effect on RBC adherence. CONCLUSION Prolonged storage of NWR RBCs increases RBC adherence to endothelial cells in vitro. WBC reduction before storage abrogates the effect of storage duration on increased adhesion. Studies to assess whether an in vivo effect occurs are required.
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Affiliation(s)
- Cynthia S Luk
- London Health Sciences Center, the Lawson Health Research Institute, Canadian Blood Services, and the University of Western Ontario, London, Ontario, Canada
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23
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Waterkeyn JG, Cowman AF, Cooke BM. Plasmodium falciparum: gelatin enrichment selects for parasites with full-length chromosome 2. implications for cytoadhesion assays. Exp Parasitol 2001; 97:115-8. [PMID: 11281709 DOI: 10.1006/expr.2000.4593] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Waterkeyn, J. G., Cowman, A. F., and Cooke, B. M. 2001. Plasmodium falciparum: Gelatin enrichment selects for parasites with full-length chromosome 2. Implications for cytoadhesion assays. Experimental Parasitology 97, 115-118.
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Affiliation(s)
- J G Waterkeyn
- The Walter and Eliza Hall Institute of Medical Research, Post Office, Royal Melbourne Hospital, Melbourne 3052, Australia
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24
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Cooke BM, Mohandas N, Coppel RL. The malaria-infected red blood cell: structural and functional changes. ADVANCES IN PARASITOLOGY 2001; 50:1-86. [PMID: 11757330 PMCID: PMC7130133 DOI: 10.1016/s0065-308x(01)50029-9] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The asexual stage of malaria parasites of the genus Plasmodium invade red blood cells of various species including humans. After parasite invasion, red blood cells progressively acquire a new set of properties and are converted into more typical, although still simpler, eukaryotic cells by the appearance of new structures in the red blood cell cytoplasm, and new proteins at the red blood cell membrane skeleton. The red blood cell undergoes striking morphological alterations and its rheological properties are considerably altered, manifesting as red blood cells with increased membrane rigidity, reduced deformability and increased adhesiveness for a number of other cells including the vascular endothelium. Elucidation of the structural changes in the red blood cell induced by parasite invasion and maturation and an understanding of the accompanying functional alterations have the ability to considerably extend our knowledge of structure-function relationships in the normal red blood cell. Furthermore, interference with these interactions may lead to previously unsuspected means of reducing parasite virulence and may lead to the development of novel antimalarial therapeutics.
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Affiliation(s)
- B M Cooke
- Department of Microbiology, P.O. Box 53, Monash University, Victoria 3800, Australia
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25
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Cooke B, Coppel R, Wahlgren M. Falciparum malaria: sticking up, standing out and out-standing. PARASITOLOGY TODAY (PERSONAL ED.) 2000; 16:416-20. [PMID: 11006472 DOI: 10.1016/s0169-4758(00)01753-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cytoadherence is believed to be fundamental for the survival of Plasmodium falciparum in vivo and, uniquely, is a major determinant of the virulence of this parasite. Despite the widely professed importance of cytoadhesion in the development of severe disease, there are a number of aspects of this highly complex process that remain poorly understood. Recent progress in the understanding of cytoadhesive phenomena was discussed extensively at the Molecular Approaches to Malaria conference, Lorne, Australia, 2-5 February 2000. Here, Brian Cooke, Mats Wahlgren and Ross Coppel consider just how far we have progressed during the past 30 years and highlight what is still missing in our understanding of the mechanisms and clinical relevance of this apparently vital process.
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Affiliation(s)
- B Cooke
- Department of Microbiology, PO Box 53, Monash University, 3800, Victoria, Australia.
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26
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Eichelbrönner O, Sielenkämper A, Cepinskas G, Sibbald WJ, Chin-Yee IH. Endotoxin promotes adhesion of human erythrocytes to human vascular endothelial cells under conditions of flow. Crit Care Med 2000; 28:1865-70. [PMID: 10890634 DOI: 10.1097/00003246-200006000-00030] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To investigate the effects of endotoxin on adhesion of human red blood cells to human vascular endothelial cells under conditions of flow. DESIGN Prospective, randomized, controlled in vitro study. SETTINGS University-affiliated cell biology laboratory. SUBJECTS Human erythrocytes and human vascular endothelial cells. INTERVENTIONS Fresh human erythrocytes and human vascular endothelial cells grown as monolayers were incubated with either saline or endotoxin. After incubation, endothelial monolayers were superfused with erythrocytes, and the number of erythrocytes adhering to the endothelial monolayer was quantified. MEASUREMENTS AND MAIN RESULTS Adhesion of erythrocytes to vascular endothelium was measured under conditions of continuous flow in different settings: a) exposure of both endothelial cells and erythrocytes to saline; b) incubation of both erythrocytes and endothelial cells with endotoxin; c) exposure of erythrocytes only to endotoxin; d) incubation of endothelial cells only to endotoxin; and e) both the endothelial cells and erythrocytes incubated with different concentrations of endotoxin. Erythrocyte adhesion in the saline control group was 71 +/- 8 cells/mm2. Incubation of both components with endotoxin increased the number of adhesive erythrocytes to 172 +/- 9 cells/mm2 (p < .05). When only the endothelial cells were treated with endotoxin, 142 +/- 8 cells/mm2 adhered to the endothelial monolayer, whereas the incubation of the erythrocytes only to endotoxin resulted in adhesion of 102 +/- 3 cells/mm2. Decreasing concentrations of endotoxin reduced adhesion from 172 +/- 9 cells/mm2 (endotoxin, 75 microg/mL) to 165 +/- 9 cells/mm2 (endotoxin, 25 microg/mL), 153 +/- 4 cells/mm2 (endotoxin, 1 microg/mL), and 146 +/- 6.1 cells/mm2 (endotoxin, 5 ng/mL). CONCLUSIONS Exposure of human erythrocytes and human venous vascular endothelial cells to an inflammatory stimulus such as endotoxin promotes a dose-dependent adhesion of erythrocytes to endothelium in a dynamic environment. These adhesive erythrocyte-endothelium interactions can be produced by exposure of either red blood cells or endothelial cells to endotoxin, with a higher degree of adhesion after activation of the endothelial cell component.
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Affiliation(s)
- O Eichelbrönner
- A.C. Burton Vascular Biology Laboratory, London Health Sciences Centre, Ontario, Canada
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27
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Rogers NJ, Hall BS, Obiero J, Targett GA, Sutherland CJ. A model for sequestration of the transmission stages of Plasmodium falciparum: adhesion of gametocyte-infected erythrocytes to human bone marrow cells. Infect Immun 2000; 68:3455-62. [PMID: 10816498 PMCID: PMC97624 DOI: 10.1128/iai.68.6.3455-3462.2000] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
With the aim of developing an appropriate in vitro model of the sequestration of developing Plasmodium falciparum sexual-stage parasites, we have investigated the cytoadherence of gametocytes to human bone marrow cells of stromal and endothelial origin. Developing stage III and IV gametocytes, but not mature stage V gametocytes, adhere to bone marrow cells in significantly higher densities than do asexual-stage parasites, although these adhesion densities are severalfold lower than those encountered in classical CD36-dependent assays of P. falciparum cytoadherence. This implies that developing gametocytes undergo a transition from high-avidity, CD36-mediated adhesion during stages I and II to a lower-avidity adhesion during stages III and IV. We show that this adhesion is CD36 independent, fixation sensitive, stimulated by tumor necrosis factor alpha, and dependent on divalent cations and serum components. These data suggest that gametocytes and asexual parasites utilize distinct sets of receptors for adhesion during development in their respective sequestered niches. To identify receptors for gametocyte-specific adhesion of infected erythrocytes to bone marrow cells, we tested a large panel of antibodies for the ability to inhibit cytoadherence. Our results implicate ICAM-1, CD49c, CD166, and CD164 as candidate bone marrow cell receptors for gametocyte adhesion.
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Affiliation(s)
- N J Rogers
- Immunology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London WC1E 7HT, United Kingdom
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28
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Alecrim WD, Espinosa FE, Alecrim MG. Plasmodium falciparum infection in the pregnant patient. Infect Dis Clin North Am 2000; 14:83-95, viii-ix. [PMID: 10738674 DOI: 10.1016/s0891-5520(05)70219-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Malaria should be considered a risk factor in women who are pregnant, principally when the infection is Plasmodium falciparum. Moreover, the risk is greater if the woman is pregnant for the first time; if she has no immunity for malaria; if the diagnosis is made late; or if P. falciparum shows resistance to antimalarial drugs. This article presents the most significant aspects of P. falciparum malaria during pregnancy, including information about treatments and prophylaxis.
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Affiliation(s)
- W D Alecrim
- Tropical Medicine Foundation of Amazon, Brazil.
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Beeson JG, Rogerson SJ, Cooke BM, Reeder JC, Chai W, Lawson AM, Molyneux ME, Brown GV. Adhesion of Plasmodium falciparum-infected erythrocytes to hyaluronic acid in placental malaria. Nat Med 2000; 6:86-90. [PMID: 10613830 PMCID: PMC2613479 DOI: 10.1038/71582] [Citation(s) in RCA: 215] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Infection with Plasmodium falciparum during pregnancy leads to the accumulation of parasite-infected erythrocytes in the placenta, and is associated with excess perinatal mortality, premature delivery and intrauterine growth retardation in the infant, as well as increased maternal mortality and morbidity. P. falciparum can adhere to specific receptors on host cells, an important virulence factor enabling parasites to accumulate in various organs. We report here that most P. falciparum isolates from infected placentae can bind to hyaluronic acid, a newly discovered receptor for parasite adhesion that is present on the placental lining. In laboratory isolates selected for specific high-level adhesion, binding to hyaluronic acid could be inhibited by dodecamer or larger oligosaccharide fragments or polysaccharides, treatment of immobilized receptor with hyaluronidase, or treatment of infected erythrocytes with trypsin. In vitro flow-based assays demonstrated that high levels of adhesion occurred at low wall shear stress, conditions thought to prevail in the placenta. Our findings indicate that adhesion to hyaluronic acid is involved in mediating placental parasite accumulation, thus changing the present understanding of the mechanisms of placental infection, with implications for the development of therapeutic and preventative interventions.
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Affiliation(s)
- J G Beeson
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
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30
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Schetters TP, Eling WM. Can Babesia infections be used as a model for cerebral malaria? PARASITOLOGY TODAY (PERSONAL ED.) 1999; 15:492-7. [PMID: 10557150 DOI: 10.1016/s0169-4758(99)01566-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Infections with certain species of Plasmodium and Babesia induce, among other symptoms, cerebral pathology. The finding of heavily parasitized cerebral capillaries upon postmortem examination has led to the assumption that blockage of capillaries with infected red blood cells caused the cerebral symptoms and subsequent death. As this type of cerebrovascular pathology is found both in humans dying from malaria and in cattle dying from babesiosis, the latter could possibly be used as an animal model for the study of human cerebral malaria. However, before such a model system is adopted, the experimental data concerning cerebral pathology of babesiosis needs critical evaluation. Here, Theo Schetters and Wijnand Eling review the pathological mechanisms in cerebral babesiosis and relate these to cerebral malaria. Finally, they discuss the use of animal model systems for specific aspects of the pathological picture.
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Affiliation(s)
- T P Schetters
- Intervet International b.v., Parasitology R&D Department, PO Box 31, 5830 AA Boxmeer, The Netherlands.
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31
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Abstract
Antigenic variation, rosetting and cytoadhesion are key determinants in the survival and virulence of the malaria parasite Plasmodium falciparum. These properties reside in a multigene protein family called P. falciparum erythrocyte membrane protein I (PfEMPI), encoded by the large and diverse var gene family. PfEMPI plays a central role in the biology of P. falciparum and its interaction with the human host. The molecular mechanism and the domains involved in cytoadherence, rosetting and antigenic variation are beginning to unfold. Domains mediating rosetting and adhesion to several key host receptors have already been identified. Understanding the role of PfEMPI in the pathogenesis and survival of malaria parasites is the key for the development of anti-adhesion vaccines and therapeutics to reduce the mortality and morbidity of P. falciparum infections.
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Affiliation(s)
- D I Baruch
- Laboratory of Parasitic Diseases, NIAID/NIH, Bethesda, MD 20892-0425, USA
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32
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Lejoly-Boisseau H, Appriou M, Seigneur M, Pruvost A, Tribouley-Duret J, Tribouley J. Schistosoma mansoni: in vitro adhesion of parasite eggs to the vascular endothelium. Subsequent inhibition by a monoclonal antibody directed to a carbohydrate epitope. Exp Parasitol 1999; 91:20-9. [PMID: 9920039 DOI: 10.1006/expr.1999.4348] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Schistosoma mansoni eggs come into direct contact with the vascular endothelium, particularly in the postcapillary venules of the mesenteric tract (oviposition site). We investigated the adhesion of eggs to endothelial cells in a static in vitro assay and in a flow-based in vitro assay. Live S. mansoni eggs rapidly attached, in a time-dependent manner, to the human endothelial cell line ECV 304, but not KOH-treated eggs. Activation of ECV monolayers with interleukin-1 promoted live S. mansoni eggs adhesion. An in vitro flow-based assay of human umbilical vein endothelial cells (HUVEC) showed the influence of wall shear stresses on the attachment of eggs to endothelial cells, particularly under postcapillary venule shear stress conditions. Interleukin-1 activation of HUVEC promoted adhesion between live eggs and endothelial cells. Higher wall shear stresses were needed to obtain the detachment of eggs from activated endothelial cells than control cells. Preincubation of interleukin-1-activated HUVEC, in a static in vitro assay, with monoclonal antibodies specific for intercellular adhesion molecule-1, E-selectin, and vascular cell adhesion molecule-1 significantly decreased adhesion of live eggs. Previous studies have shown that a monoclonal antibody specific for a schistosome carbohydrate epitope abundant in eggs is related to the Lewis X antigen. In this study, the anti-Lewis X-specific monoclonal antibody was used for adhesion-inhibition assays. Preincubation of eggs with this monoclonal antibody significantly decreased adhesion of live eggs to interleukin-1-activated HUVEC cultured in vitro. These results suggest that surface adhesion molecules, expressed by endothelial cells under conditions of interleukin-1 activation, directly participate in egg adhesion and that egg carbohydrate antigens play an important role in live S. mansoni egg adhesion to the vascular endothelium.
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Affiliation(s)
- H Lejoly-Boisseau
- Laboratoire d'Immunologie et de Parasitologie, UFR des Sciences Pharmaceutiques, Université Victor Segalen Bordeaux 2, France
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Cooke BM, Nicoll CL, Baruch DI, Coppel RL. A recombinant peptide based on PfEMP-1 blocks and reverses adhesion of malaria-infected red blood cells to CD36 under flow. Mol Microbiol 1998; 30:83-90. [PMID: 9786187 DOI: 10.1046/j.1365-2958.1998.01040.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During falciparum malaria infection, severe complications ensue because parasitized red blood cells (PRBCs) adhere to endothelial cells and accumulate in the microvasculature. At the molecular level, adhesion is mediated by interaction of Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP-1) on the PRBC surface with receptors on the surface of endothelial cells, including CD36. We have shown that a recombinant 179-residue subfragment of PfEMP-1 (rC1-2[1-179]), which encompasses the CD36-binding region, inhibits and reverses adhesion of PRBCs to CD36 under physiologically relevant flow conditions. rC1-2[1-179] inhibited adhesion in a concentration-dependent manner over the range 100 pM to 2 microM, with up to 99% of adhesion blocked at the highest concentration tested. The antiadhesive activity of rC1-2[1-179] was not strain specific and almost totally ablated adhesion of four different parasite lines. Furthermore, rC1-2[1-179] showed remarkable ability to progressively reverse adhesion when flowed over adherent PRBCs for 2h. The effect of rC1-2[1-179] was, however, specific for CD36-mediated adhesion and had no effect on adhesion mediated by CSA. Interference with binding of PRBCs to the vascular endothelium using rC1-2[1-179] or smaller organic mimetics may be a useful therapeutic approach to ameliorate severe complications of falciparum malaria.
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Affiliation(s)
- B M Cooke
- Department of Microbiology, Monash University, Clayton, Victoria, Australia.
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Schetters TP, Kleuskens JA, Scholtes NC, Pasman JW, Goovaerts D. Vaccination of dogs against Babesia canis infection. Vet Parasitol 1997; 73:35-41. [PMID: 9477490 DOI: 10.1016/s0304-4017(97)00044-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This paper describes the clinico-pathological parameters measured in dogs that were vaccinated against Babesia canis using soluble parasite antigens (SPA) and then challenged. The packed cell volume (PCV) and the plasma creatinine value decreased immediately after challenge. Actual PCV values could be predicted in the first 5-6 days of the infection, assuming that creatinine values were modulated by increase of plasma volume. This association no longer existed after that time, and observations indicated splenic involvement in reduction of numbers of circulating erythrocytes. The anaemia due to B. canis infection appears to be the result of a multifactorial process including plasma volume increase, erythrocyte retention in the spleen and erythrocyte destruction, partly due to parasite proliferation. Vaccination limited the reduction of PCV values, and the development of splenomegaly. Differences in protection between vaccinated and control animals became apparent 6 days after infection, when a memory immune response becomes operative, and the onset of recovery of vaccinated animals correlated with the onset of antibody production against SPA.
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Affiliation(s)
- T P Schetters
- Intervet International B.V., Department of Parasitology, Boxmeer, The Netherlands
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Bennett BJ, Mohandas N, Coppel RL. Defining the minimal domain of the Plasmodium falciparum protein MESA involved in the interaction with the red cell membrane skeletal protein 4.1. J Biol Chem 1997; 272:15299-306. [PMID: 9182557 DOI: 10.1074/jbc.272.24.15299] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
During part of its life cycle, the protozoan parasite Plasmodium falciparum lives within the human red blood cell and modifies both the structural and functional properties of the red cell. It does this by synthesizing a number of polypeptides that it transports into the red cell cytoplasm and to the red cell membrane. One of these transported proteins, MESA (mature parasite-infected erythrocyte surface antigen), is anchored to the red cell membrane by noncovalent interaction with erythrocyte protein 4.1. We have utilized a combination of in vitro transcription and translation and a membrane binding assay to identify the protein sequence involved in anchoring MESA to the membrane. Labeled fragments of different regions of the MESA protein were evaluated for their ability to bind to inside-out vesicle membrane preparations of human red cells. Binding was dependent on the presence of red cell membrane proteins and was abolished either by trypsin treatment or by selective depletion of membrane proteins. Binding was specific and could be inhibited by the addition of competing protein, with an IC50 of (6.3 +/- 1.2) x 10(-7) M, indicative of a moderate affinity interaction. Fractionation studies demonstrated that binding fragments interacted most efficiently with membrane protein fractions that had been enriched in protein 4.1. Binding inhibition experiments using synthetic peptides identified the binding domain of MESA for protein 4.1 as a 19-residue sequence near the amino terminus of MESA, a region capable of forming an amphipathic helix.
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Affiliation(s)
- B J Bennett
- Walter and Eliza Hall Institute of Medical Research, Victoria 3050, Australia
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Rogerson SJ, Novakovic S, Cooke BM, Brown GV. Plasmodium falciparum-infected erythrocytes adhere to the proteoglycan thrombomodulin in static and flow-based systems. Exp Parasitol 1997; 86:8-18. [PMID: 9149236 DOI: 10.1006/expr.1996.4142] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Plasmodium falciparum-infected erythrocytes can bind to the glycosaminoglycan chondroitin sulfate A. In this paper, we demonstrate that thrombomodulin, a proteoglycan present on endothelial cells and placental syncytiotrophoblasts, supports binding of selected lines of P. falciparum-infected erythrocytes in both static and flow-based assays, and that adhesion is dependent on the presence of the chondroitin sulfate A chain of thrombomodulin. Chondroitinase treatment of thrombomodulin abolished binding, and free chondroitin sulfate A prevented it, whereas other soluble glycosaminoglycans had little or no effect. Soluble thrombomodulin (with, but not without, its chondroitin sulfate chain) inhibited binding at 40 micrograms/ml, but not at physiological concentrations. Parasitized erythrocytes bound to cells expressing thrombomodulin, including human umbilical vein endothelial cells and A549 cells, and binding was inhibited by free chondroitin sulfate A. Established binding to A549 cells or to immobilized thrombomodulin was substantially reversed by chondroitin sulfate A at 10 micrograms/ml. The chondroitin sulfate chain of thrombomodulin is a receptor for malaria-infected erythrocytes in static assays and under physiological flow.
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Affiliation(s)
- S J Rogerson
- Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Victoria, Australia
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