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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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Kraisin S, Palasuwan A, Popruk S, Nantakomol D. Reduced ADAMTS13 activity is associated with an ADAMTS13 SNP, fever and microparticles in a malaria-like model. Malar J 2014; 13:3. [PMID: 24386898 PMCID: PMC3882324 DOI: 10.1186/1475-2875-13-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 12/29/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Severe falciparum malaria (SM) remains a major cause of death in tropical countries. The reduced activity of ADAMTS13, increasing levels of ultra-large von Willebrand factor (ULVWF) in SM patients, are assumed as factors that intensify disease severity. However, the reason why ADAMTS13 activity is reduced in SM remains unclear. OBJECTIVES To investigate whether rs4962153, febrile temperature, and microparticles, contribute to reduced ADAMTS13 activity. METHODS Genotypic association of rs4962153 with ADAMTS13 antigen and activity was examined in 362 healthy Thai participants. The collagen binding assay was used to study the effects of febrile temperature and microparticles on ADAMTS13 activity. RESULTS ADAMTS13 antigen and activity were decreased in participants with AA genotype, compared to AG and GG (antigen: p-value = 0.014, and < 0.001; activity: p-value = 0.036, and < 0.002, respectively). There was significantly reduced ADAMTS13 antigen in AG compared to GG (p-value = 0.013), but not in ADAMTS13 activity (p-value = 0.082). The number of rs4962153 A alleles correlated with the reduced level of antigen and activity (p-value <0.001 and p-value = 0.001, respectively). MPs showed an inhibitory effect on ADAMTS13 activity (p-value = 0.025). Finally, ADAMTS13 activity was decreased in a temperature and time-dependent manner. The interaction between these two factors was also observed (p-value <0.001). CONCLUSIONS These findings suggest that the A allele of rs4962153, MPs, and febrile temperature, contribute to reduce ADAMTS13 activity in plasma. These data are useful in malaria or other diseases with reduced ADAMTS13 activity.
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Affiliation(s)
| | | | | | - Duangdao Nantakomol
- Department of Clinical Microscopy, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok, Thailand.
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Thachil J, Owusu-Ofori S, Bates I. Haematological Diseases in the Tropics. MANSON'S TROPICAL INFECTIOUS DISEASES 2014. [PMCID: PMC7167525 DOI: 10.1016/b978-0-7020-5101-2.00066-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Angchaisuksiri P. Coagulopathy in malaria. Thromb Res 2013; 133:5-9. [PMID: 24099998 DOI: 10.1016/j.thromres.2013.09.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 09/18/2013] [Accepted: 09/18/2013] [Indexed: 12/18/2022]
Abstract
Blood coagulation activation is frequently found in patients with malaria. Clinically apparent bleeding or disseminated intravascular coagulation (DIC) is associated with very severe disease and a high mortality. Protein C, protein S, and antithrombin levels were found to be low in P. falciparum, but were normal in P. vivax infection. Plasma levels of plasminogen activator inhibitor-1 were high in cases of P. falciparum infection whereas tissue plasminogen activator levels were low. Elevated plasma levels of von Willebrand factor (vWF) and vWF propeptide, thrombomodulin, endothelial microparticles have been reported in P. falciparum-infected patients. It has been demonstrated that severe P. falciparum infection is associated with acute endothelial cell (EC) activation, abnormal circulating ultralarge vWF multimers, and a significant reduction in plasma ADAMTS13 function. These changes may result in intravascular platelet aggregation, thrombocytopenia, and microvascular disease. It has also been shown that P. falciparum-parasitized red blood cells (pRBCs) induce tissue factor (TF) expression in microvascular ECs in vitro. Recently, loss of endothelial protein C receptor (EPCR) localized to sites of cytoadherent pRBCs in cerebral malaria has been demonstrated. Severe malaria is associated with parasite binding to EPCR. The cornerstone of the treatment of coagulopathy in malaria is the use of effective anti-malarial agents. DIC with spontaneous systemic bleeding should be treated with screened blood products. Study in Thailand has shown that for patients who presented with parasitemia >30% and severe systemic complications such as acute renal failure and ARDS, survival was superior in the group who received exchange transfusion. The use of heparin is generally restricted to patients with DIC and extensive deposition of fibrin, as occurs with purpura fulminans or acral ischemia. Antiplatelet agents interfere with the protective effect of platelets against malaria and should be avoided.
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Affiliation(s)
- Pantep Angchaisuksiri
- Division of Hematology, Department of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
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The clinical implications of ADAMTS13 function: the perspectives of haemostaseologists. Thromb Res 2013; 132:403-7. [PMID: 24050828 DOI: 10.1016/j.thromres.2013.07.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 07/17/2013] [Accepted: 07/21/2013] [Indexed: 02/08/2023]
Abstract
Apart from TTP, ADAMTS13 may be an important player in those conditions where Von Willebrand Factor and the Platelet Glycoprotein GP Ib axis have a part to play in the pathogenesis. This includes stroke, myocardial infarction, sepsis and inflammatory condition. This article reviews the literature in these conditions.
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Suidan GL, Brill A, De Meyer SF, Voorhees JR, Cifuni SM, Cabral JE, Wagner DD. Endothelial Von Willebrand factor promotes blood-brain barrier flexibility and provides protection from hypoxia and seizures in mice. Arterioscler Thromb Vasc Biol 2013; 33:2112-20. [PMID: 23825365 DOI: 10.1161/atvbaha.113.301362] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Aberrant blood-brain barrier (BBB) permeability is a hallmark pathology of many central nervous system diseases. von Willebrand factor (VWF) is stored in endothelial Weibel-Palade bodies from where it is released on activation into plasma and basement membrane. The role of VWF in endothelial homeostasis is unclear. The goal of this study was to assess the role of VWF in disease models associated with increased BBB permeability. APPROACH AND RESULTS We did not find any differences in BBB permeability to Evans blue dye at baseline between wild-type and VWF(-/-) animals. We next used 2 models presenting with increased BBB permeability, hypoxia/reoxygenation and pilocarpine-induced status epilepticus, to assess the response of VWF(-/-) animals. In both models, VWF(-/-) mice maintained a tighter BBB than wild-type mice. VWF(-/-) mice fared worse in both conditions, with ≈ 100% of VWF(-/-) mice dying within 120 minutes after pilocarpine administration, whereas >80% of wild-type animals survived. Investigation into the status of tight junction proteins revealed that VWF(-/-) mice expressed more claudin-5 at baseline. In vitro work confirmed that the presence of subendothelial VWF is inhibitory to claudin-5 expression. CONCLUSIONS VWF deficiency confers partial preservation of BBB integrity after hypoxia/reoxygenation and seizures. Surprisingly, this decrease in BBB permeability did not result in protection of animals because they demonstrated more severe pathology in both models compared with wild-type animals. These data suggest that a rigid BBB is detrimental (to the organism) during certain disease states and that VWF release may provide desired flexibility under stress.
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Crossing the wall: The opening of endothelial cell junctions during infectious diseases. Int J Biochem Cell Biol 2013; 45:1165-73. [DOI: 10.1016/j.biocel.2013.03.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 03/05/2013] [Accepted: 03/15/2013] [Indexed: 12/22/2022]
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Manning L, Davis TME. The mechanistic, diagnostic and prognostic utility of biomarkers in severe malaria. Biomark Med 2013; 7:363-80. [DOI: 10.2217/bmm.13.50] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Malaria remains an important global cause of severe illness and mortality. This literature review summarizes available data on how biomarkers might be applied to diagnose, prognosticate and provide mechanistic insights in patients with severe malaria. Of the large number of candidate biomarkers, only PfHRP2 has consistently demonstrated clinical utility and, when incorporated into rapid antigen detection tests, has shown diagnostic sensitivity above 95%, which is at least as good as light microscopy. As a quantitative test, PfHRP2 also shows some promise in differentiating severe malarial from non-malarial disease in areas where asymptomatic carriage of malaria parasites is common, and possibly as a tool to estimate sequestered parasite burden and subsequent mortality. Biomarkers such as pLDH and panmalarial antigen have lower sensitivity for non-falciparum malaria in rapid antigen detection tests. There is an urgent need to discover and validate better biomarkers for incorporation into rapid antigen detection tests in countries where Plasmodium vivax is a common cause of severe disease. A large number of host-derived acute-phase reactants, markers of endothelial dysfunction and immune mediators have been proposed as biomarkers. Although they have provided mechanistic insights into the immunopathology of severe malaria, their roles as clinical tools remain uncertain.
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Affiliation(s)
- Laurens Manning
- School of Medicine & Pharmacology, Fremantle Hospital & Health Service, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Timothy Mark Earls Davis
- School of Medicine & Pharmacology, Fremantle Hospital & Health Service, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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Chen SF, Xia ZL, Han JJ, Wang YT, Wang JY, Pan SD, Wu YP, Zhang B, Li GY, Du JW, Gao HQ, de Groot PG, de Laat B, Hollestelle MJ. Increased active von Willebrand factor during disease development in the aging diabetic patient population. AGE (DORDRECHT, NETHERLANDS) 2013; 35:171-177. [PMID: 22120183 PMCID: PMC3543747 DOI: 10.1007/s11357-011-9335-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 10/25/2011] [Indexed: 05/31/2023]
Abstract
Type 2 diabetes is known to cause endothelial activation resulting in the secretion of von Willebrand factor (VWF). We have shown that levels of VWF in a glycoprotein Ib-binding conformation are increased in specific clinical settings. The aim of the current study is to investigate whether active VWF levels increase during aging and the development of diabetes within the population of patients suffering from type 2 diabetes. Patients and controls were divided into two groups based on age: older and younger than 60 years of age. VWF antigen, VWF propeptide, VWF activation factor and total active VWF were measured. Patients older than 60 years of age had increased levels of total active VWF, VWF activation factor and VWF propeptide compared to younger patients and controls. All measured VWF parameters were associated with age in diabetic patients. Total active VWF and VWF propeptide correlated with the period of being diagnosed with diabetes. Regression analyses showed that especially the VWF activation factor was strongly associated with diabetes in patients older than 60 years of age. In conclusion, we found that the conformation of VWF could be involved in the disease process of diabetes and that the VWF in a glycoprotein Ib-binding conformation could play a role as risk marker during the development of diabetes in combination with an increase in age. Our study shows that the active quality of VWF was more important than the quantity.
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Affiliation(s)
- Shuang Feng Chen
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
| | - Zuo Li Xia
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
- Department of Aging Medicine, Taishan Medical University, Taian, Shandong China
| | - Ji Ju Han
- Institute of Arthrosclerosis, Taishan Medical University, Taian, Shandong China
| | - Yi Ting Wang
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
| | - Ji Yue Wang
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
| | - Shao Dong Pan
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
| | - Ya Ping Wu
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
- Department of Clinical Chemistry and Haematology, University Medical Centre Utrecht, G03.550, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Bin Zhang
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
| | - Guang Yao Li
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
| | - Jing Wei Du
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
| | - Hen Qiang Gao
- SPKLOMHNMB and Central Laboratory, Liaocheng People’ Hospital, Taishan Medical University, Liaocheng, Shandong China
| | - Philip G. de Groot
- Department of Clinical Chemistry and Haematology, University Medical Centre Utrecht, G03.550, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Bas de Laat
- Department of Clinical Chemistry and Haematology, University Medical Centre Utrecht, G03.550, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- Sanquin Research, Sanquin Blood Supply Foundation, Amsterdam, The Netherlands
| | - Martine J. Hollestelle
- Department of Clinical Chemistry and Haematology, University Medical Centre Utrecht, G03.550, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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Abstract
von Willebrand factor (VWF) is amongst others synthesized by endothelial cells and stored as ultra-large (UL) VWF multimers in Weibel-Palade bodies. Although UL-VWF is proteolysed by ADAMTS13 (a disintegrin-like and metalloprotease domain with thrombospondin type-1 motif, number 13) on secretion from endothelial cells, in vitro experiments in the absence of ADAMTS13 have demonstrated that a proportion of these UL-VWF multimers remain anchored to the activated endothelium. These multimers unravel, bind platelets, and wave in the direction of the flow. These so-called VWF "strings" have also been visualized in vivo, lining the lumen of activated mesenteric veins of Adamts13(-/-) mice. Various studies have demonstrated the extraordinary length of these VWF strings, the availability of their platelet binding and ADAMTS13 cleavage sites, and the possible nature of their endothelial attachment. VWF strings are also capable of tethering leukocytes and parasite-infected red blood cells. However, the majority of studies have been performed in the absence of ADAMTS13, a condition only experienced in thrombotic thrombocytopenic purpura. A normal functional role of VWF strings in healthy persons or in other disease pathologies remains unclear. In this review, we discuss some of the puzzling characteristics of VWF strings, and we debate whether the properties of VWF strings in the absence of ADAMTS13 might be relevant for understanding (patho)physiologic mechanisms.
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Cruz LN, Wu Y, Craig AG, Garcia CRS. Signal transduction in Plasmodium-Red Blood Cells interactions and in cytoadherence. AN ACAD BRAS CIENC 2012; 84:555-72. [PMID: 22634746 DOI: 10.1590/s0001-37652012005000036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 03/09/2012] [Indexed: 12/19/2022] Open
Abstract
Malaria is responsible for more than 1.5 million deaths each year, especially among children (Snow et al. 2005). Despite of the severity of malaria situation and great effort to the development of new drug targets (Yuan et al. 2011) there is still a relative low investment toward antimalarial drugs. Briefly there are targets classes of antimalarial drugs currently being tested including: kinases, proteases, ion channel of GPCR, nuclear receptor, among others (Gamo et al. 2010). Here we review malaria signal transduction pathways in Red Blood Cells (RBC) as well as infected RBCs and endothelial cells interactions, namely cytoadherence. The last process is thought to play an important role in the pathogenesis of severe malaria. The molecules displayed on the surface of both infected erythrocytes (IE) and vascular endothelial cells (EC) exert themselves as important mediators in cytoadherence, in that they not only induce structural and metabolic changes on both sides, but also trigger multiple signal transduction processes, leading to alteration of gene expression, with the balance between positive and negative regulation determining endothelial pathology during a malaria infection.
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Affiliation(s)
- Laura N Cruz
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Brasil
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Djamiatun K, van der Ven AJAM, de Groot PG, Faradz SMH, Hapsari D, Dolmans WMV, Sebastian S, Fijnheer R, de Mast Q. Severe dengue is associated with consumption of von Willebrand factor and its cleaving enzyme ADAMTS-13. PLoS Negl Trop Dis 2012; 6:e1628. [PMID: 22563509 PMCID: PMC3341341 DOI: 10.1371/journal.pntd.0001628] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 03/08/2012] [Indexed: 12/27/2022] Open
Abstract
Background Thrombocytopenia, bleeding and plasma leakage are cardinal features of severe dengue. Endothelial cell activation with exocytosis of Weibel-Palade bodies (WPBs) may play an etiological role in this condition. Methods and Principal Findings In a cohort of 73 Indonesian children with dengue hemorrhagic fever (DHF), of which 30 with dengue shock syndrome (DSS), we measured plasma levels of the WPB constituents von Willebrand factor antigen (VWF:Ag), VWF propeptide and osteoprotegerin (OPG), together with activity levels of the VWF-cleaving enzyme ADAMTS-13 and the amount of VWF in a platelet binding conformation (VWF activation factor). Compared with healthy controls (n = 17), children with DHF/DSS had significantly higher levels of VWF:Ag, VWF propeptide and OPG and decreased ADAMTS-13 activity. The VWF activation factor was also significantly higher in DHF/DSS and highest in children who died. There were significant differences in the kinetics of the various WPB constituents: VWF propeptide and OPG levels decreased toward discharge, while VWF:Ag levels were lower than expected at enrollment with plasma levels increasing toward discharge. Moreover, VWF propeptide levels correlated better with markers of disease severity (platelet count, liver enzymes, serum albumin and pleural effusion index) than corresponding VWF levels. Together, these findings suggest that there is consumption of VWF in DHF/DSS. In 4 out of 15 selected children with low ADAMTS-13 levels on admission, we found a remarkable reduction in the large and intermediate VWF multimers in the discharge blood samples, consistent with an acquired von Willebrand disease. Conclusion These findings suggest that severe dengue is associated with exocytosis of WPBs with increased circulating levels of VWF:Ag, VWF propeptide and OPG. High circulating levels of VWF in its active conformation, together with low ADAMTS-13 activity levels, are likely to contribute to the thrombocytopenia and complications of dengue. During the convalescence phase, qualitative defects in VWF with loss of larger VWF multimers may develop. Severe dengue infections are characterized by thrombocytopenia, clinical bleeding and plasma leakage. Activation of the endothelium, the inner lining of blood vessels, leads to the secretion of storage granules called Weibel Palade bodies (WPBs). We demonstrated that severe dengue in Indonesian children is associated with a strong increase in plasma levels of the WPB constituents von Willebrand factor (VWF), VWF propeptide and osteoprotegerin (OPG). An increased amount of the hemostatic protein VWF was in a hyperreactive, platelet binding conformation, and this was most pronounced in the children who died. VWF levels at enrollment were lower than expected from concurrent VWF propeptide and OPG levels and VWF levels did not correlate well with markers of disease severity. Together, this suggests that VWF is being consumed during severe dengue. Circulating levels of the VWF-cleaving enzyme ADAMTS-13 were reduced. VWF is a multimeric protein and a subset of children had a decrease in large and intermediate VWF multimers at discharge. In conclusion, severe dengue is associated with exocytosis of WPBs with consumption of VWF and low ADAMTS-13 activity levels. This may contribute to the thrombocytopenia and complications of dengue.
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Affiliation(s)
- Kis Djamiatun
- Department of Parasitology, Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - Andre J. A. M. van der Ven
- Department of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Philip G. de Groot
- Laboratory for Thrombosis and Haemostasis, Department of Clinical Chemistry and Haematology, University Medical Centre, Utrecht, The Netherlands
| | - Sultana M. H. Faradz
- Division of Human Genetics, Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - D. Hapsari
- Department of Pediatrics, Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - Wil M. V. Dolmans
- Department of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Silvie Sebastian
- Laboratory for Thrombosis and Haemostasis, Department of Clinical Chemistry and Haematology, University Medical Centre, Utrecht, The Netherlands
| | - Rob Fijnheer
- Laboratory for Thrombosis and Haemostasis, Department of Clinical Chemistry and Haematology, University Medical Centre, Utrecht, The Netherlands
| | - Quirijn de Mast
- Department of General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail:
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Park GS, Ireland KF, Opoka RO, John CC. Evidence of Endothelial Activation in Asymptomatic Plasmodium falciparum Parasitemia and Effect of Blood Group on Levels of von Willebrand Factor in Malaria. J Pediatric Infect Dis Soc 2012; 1:16-25. [PMID: 23687570 PMCID: PMC3656549 DOI: 10.1093/jpids/pis010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 01/12/2012] [Indexed: 11/14/2022]
Abstract
BACKGROUND Endothelial activation may contribute to development of severe disease from Plasmodium falciparum infection, but optimal markers of endothelial activation in severe malaria, the extent of endothelial activation in asymptomatic infection, and the effect of blood group O on endothelial activation have not been defined. METHODS Serum levels of 3 markers of endothelial activation-von Willebrand factor (VWF), soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1)-were assessed in Ugandan children with cerebral malaria (CM) (n = 86), children with uncomplicated malaria (UM) (n = 81), and community children (CC) (n = 90). RESULTS Serum VWF, sICAM-1, and sVCAM-1 levels were all elevated in asymptomatic community children with microscopy-confirmed parasitemia when compared with children without parasitemia by microscopy or polymerase chain reaction (all, P ≤ .05). Levels of VWF, sICAM-1, and sVCAM-1 were higher in children with UM than in CC (all, P < 0.001), but only VWF levels effectively distinguished CM from UM (P < 0.001), a finding confirmed by receiver operating characteristic analyses (area under the curve = 0.67; 95% confidence interval, .58-.75). Von Willebrand factor levels were lower in children with blood group O versus non-O blood groups across the disease spectrum, but VWF levels remained higher in CM versus UM, even after controlling for blood group. CONCLUSIONS Endothelial activation, as assessed by serum levels of VWF, sICAM-1, and sVCAM-1, occurs even in subclinical P. falciparum parasitemia. Von Willebrand factor levels increase with greater malaria disease severity. Blood group O is associated with lower VWF levels, but presence of blood group O alone does not explain the higher VWF levels seen in children with CM.
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Affiliation(s)
- Gregory S. Park
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis
| | - Kathleen F. Ireland
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis
| | | | - Chandy C. John
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis,Corresponding Author: Chandy C. John, Department of Pediatrics, University of Minnesota Medical School, 717 Delaware St SE, Rm 363, Minneapolis, MN 55414. E-mail:
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Conroy AL, Glover SJ, Hawkes M, Erdman LK, Seydel KB, Taylor TE, Molyneux ME, Kain KC. Angiopoietin-2 levels are associated with retinopathy and predict mortality in Malawian children with cerebral malaria: a retrospective case-control study*. Crit Care Med 2012; 40:952-9. [PMID: 22343839 PMCID: PMC3284252 DOI: 10.1097/ccm.0b013e3182373157] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVE To investigate the relationship among the angiopoietin-Tie-2 system, retinopathy, and mortality in children with cerebral malaria. DESIGN A case-control study of retinopathy-positive vs. retinopathy-negative children with clinically defined cerebral malaria. SETTING Queen Elizabeth Central Hospital in Blantyre, Malawi. SUBJECTS One hundred fifty-five children presenting with severe malaria and meeting a strict definition of clinical cerebral malaria (Blantyre Coma Score ≤ 2, Plasmodium falciparum parasitemia, no other identifiable cause for coma) were included in the study. INTERVENTIONS None. MEASUREMENTS AND MAIN RESULTS Clinical and laboratory parameters were recorded at admission and funduscopic examinations were performed. Admission levels of angiopoietin-1, angiopoietin-2, and a soluble version of their cognate receptor were measured by enzyme-linked immunosorbent assay. We show that angiopoietin-1 levels are decreased and angiopoietin-2 and soluble Tie-2 levels are increased in children with cerebral malaria who had retinopathy compared with those who did not. Angiopoietin-2 and soluble Tie-2 were independent predictors of retinopathy (adjusted odds ratio [95% CI], angiopoietin-2, 4.3 [1.3-14.6], p = .019; soluble Tie-2, 9.7 [2.1-45.8], p = .004). Angiopoietin-2 and soluble Tie-2 were positively correlated with the number of hemorrhages, the severity or retinal whitening, and the extent of capillary whitening observed on funduscopic examination (p < .05 after adjustment for multiple comparisons). Angiopoietin-2 and soluble Tie-2 levels were elevated in children with cerebral malaria who subsequently died and angiopoetin-2 was an independent predictor of death (adjusted odds ratio: 3.9 [1.2-12.7], p = .024). When combined with clinical parameters, angiopoetin-2 improved prediction of mortality using logistic regression models and classification trees. CONCLUSIONS These results provide insights into mechanisms of endothelial activation in cerebral malaria and indicate that the angiopoietin-Tie-2 axis is associated with retinopathy and mortality in pediatric cerebral malaria.
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Affiliation(s)
- Andrea L Conroy
- Sandra A Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, University Health Network-Toronto General Hospital, University of Toronto, Toronto, Canada
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65
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Grau GER, Craig AG. Cerebral malaria pathogenesis: revisiting parasite and host contributions. Future Microbiol 2012; 7:291-302. [DOI: 10.2217/fmb.11.155] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Cerebral malaria is one of a number of clinical syndromes associated with infection by human malaria parasites of the genus Plasmodium. The etiology of cerebral malaria derives from sequestration of parasitized red cells in brain microvasculature and is thought to be enhanced by the proinflammatory status of the host and virulence characteristics of the infecting parasite variant. In this article we examine the range of factors thought to influence the development of Plasmodium falciparum cerebral malaria in humans and review the evidence to support their role.
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Affiliation(s)
- Georges Emile Raymond Grau
- Vascular Immunology Unit, Department of Pathology, Sydney Medical School, The University of Sydney, Camperdown NSW 2042, Australia
- La Jolla Infectious Disease Institute, San Diego, CA 92109, USA
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66
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Kraisin S, Naka I, Patarapotikul J, Nantakomol D, Nuchnoi P, Hananantachai H, Tsuchiya N, Ohashi J. Association of ADAMTS13 polymorphism with cerebral malaria. Malar J 2011; 10:366. [PMID: 22168261 PMCID: PMC3261218 DOI: 10.1186/1475-2875-10-366] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 12/14/2011] [Indexed: 12/28/2022] Open
Abstract
Background Cerebral malaria is one of the most severe manifestations of Plasmodium falciparum malaria. The sequestration of parasitized red blood cells (PRBCs) to brain microvascular endothelium has been shown to contribute to the pathophysiology of cerebral malaria. Recent studies reported increased levels of von Willebrand factor (VWF) and reduced activity of VWF-cleaving protease, ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13), in patients with cerebral malaria. Methods Association of six single nucleotide polymorphisms (SNPs) of the ADAMTS13 gene with cerebral malaria was examined in 708 Thai patients with P. falciparum malaria. Results Among six SNPs, the derived allele of a SNP located in intron 28, rs4962153-A, was significantly associated with protection against cerebral malaria when 115 cerebral malaria patients were compared with 367 mild malaria patients (Fisher's exact P-value = 0.0057; OR = 0.27; 95% CI = 0.096-0.76). Significant association was also detected between 115 cerebral malaria and 593 non-cerebral malaria (226 non-cerebral severe malaria and 367 mild malaria) patients (Fisher's exact P-value = 0.012; OR = 0.30; 95% CI = 0.11-0.83). Conclusions Excessive adhesion of PRBCs to the platelet-decorated ultra-large VWF (ULVWF) appears to enhance the sequestration of PRBCs to cerebral microvascular endothelium. The genetic association observed in the present study implies that the regulation of platelet-decorated ULVWF strings by ADAMTS13 may play a role in the development of cerebral malaria.
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Affiliation(s)
- Sirima Kraisin
- Doctoral Program in Biomedical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
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67
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Phiri HT, Bridges DJ, Glover SJ, van Mourik JA, de Laat B, M'baya B, Taylor TE, Seydel KB, Molyneux ME, Faragher EB, Craig AG, Bunn JEG. Elevated plasma von Willebrand factor and propeptide levels in Malawian children with malaria. PLoS One 2011; 6:e25626. [PMID: 22125593 PMCID: PMC3219631 DOI: 10.1371/journal.pone.0025626] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 09/08/2011] [Indexed: 11/18/2022] Open
Abstract
Background In spite of the significant mortality associated with Plasmodium falciparum infection, the mechanisms underlying severe disease remain poorly understood. We have previously shown evidence of endothelial activation in Ghanaian children with malaria, indicated by elevated plasma levels of both von Willebrand factor (VWF) and its propeptide. In the current prospective study of children in Malawi with retinopathy confirmed cerebral malaria, we compared these markers with uncomplicated malaria, non malarial febrile illness and controls. Methods and Findings Children with cerebral malaria, mild malaria and controls without malaria were recruited into the study. All comatose patients were examined by direct and indirect ophthalmoscopy. Plasma VWF and propeptide levels were measured by ELISA. Median VWF and propeptide levels were significantly higher in patients with uncomplicated malaria than in children with non-malarial febrile illness of comparable severity, in whom levels were higher than in non-febrile controls. Median concentrations of both markers were higher in cerebral malaria than in uncomplicated malaria, and were similar in patients with and without retinopathy. Levels of both VWF and propeptide fell significantly 48 hours after commencing therapy and were normal one month later. Conclusions In children with malaria plasma VWF and propeptide levels are markedly elevated in both cerebral and mild paediatric malaria, with levels matching disease severity, and these normalize upon recovery. High levels of both markers also occur in retinopathy-negative ‘cerebral malaria’ cases, many of whom are thought to be suffering from diseases other than malaria, indicating that further studies of these markers will be required to determine their sensitivity and specificity.
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Affiliation(s)
- Happy T. Phiri
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Blantyre, Malawi
| | - Daniel J. Bridges
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Blantyre, Malawi
| | - Simon J. Glover
- Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Jan A. van Mourik
- Departments of Plasma Proteins and Blood Coagulation, Sanquin, Amsterdam, The Netherlands
| | - Bas de Laat
- Departments of Plasma Proteins and Blood Coagulation, Sanquin, Amsterdam, The Netherlands
| | | | - Terrie E. Taylor
- Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi
- Department of Internal Medicine, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, United States of America
| | - Karl B. Seydel
- Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi
- Department of Internal Medicine, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, United States of America
| | - Malcolm E. Molyneux
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Blantyre, Malawi
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Alister G. Craig
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - James E. G. Bunn
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- College of Medicine, Blantyre, Malawi
- * E-mail:
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68
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Inhaled nitric oxide reduces endothelial activation and parasite accumulation in the brain, and enhances survival in experimental cerebral malaria. PLoS One 2011; 6:e27714. [PMID: 22110737 PMCID: PMC3218025 DOI: 10.1371/journal.pone.0027714] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 10/22/2011] [Indexed: 01/08/2023] Open
Abstract
The host immune response contributes to the onset and progression of severe malaria syndromes, such as cerebral malaria. Adjunctive immunomodulatory strategies for severe malaria may improve clinical outcome beyond that achievable with artemisinin-based therapy alone. Here, we report that prophylaxis with inhaled nitric oxide significantly reduced systemic inflammation (lower TNF, IFNγ and MCP-1 in peripheral blood) and endothelial activation (decreased sICAM-1 and vWF, and increased angiopoeitin-1 levels in peripheral blood) in an experimental cerebral malaria model. Mice that received inhaled nitric oxide starting prior to infection had reduced parasitized erythrocyte accumulation in the brain, decreased brain expression of ICAM-1, and preserved vascular integrity compared to control mice. Inhaled nitric oxide administered in combination with artesunate, starting as late as 5.5 days post-infection, improved survival over treatment with artesunate alone (70% survival in the artesunate only vs. 100% survival in the artesunate plus iNO group, p = 0.03). These data support the clinical investigation of inhaled nitric oxide as a novel adjunctive therapy in patients with severe malaria.
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69
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Hawkes M, Opoka RO, Namasopo S, Miller C, Conroy AL, Serghides L, Kim H, Thampi N, Liles WC, John CC, Kain KC. Nitric oxide for the adjunctive treatment of severe malaria: hypothesis and rationale. Med Hypotheses 2011; 77:437-44. [PMID: 21745716 PMCID: PMC3162048 DOI: 10.1016/j.mehy.2011.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 06/07/2011] [Indexed: 11/24/2022]
Abstract
We hypothesize that supplemental inhaled nitric oxide (iNO) will improve outcomes in children with severe malaria receiving standard antimalarial therapy. The rationale for the hypothesized efficacy of iNO rests on: (1) biological plausibility, based on known actions of NO in modulating endothelial activation; (2) pre-clinical efficacy data from animal models of experimental cerebral malaria; and (3) a human trial of the NO precursor l-arginine, which improved endothelial function in adults with severe malaria. iNO is an attractive new candidate for the adjunctive treatment of severe malaria, given its proven therapeutic efficacy in animal studies, track record of safety in clinical practice and numerous clinical trials, inexpensive manufacturing costs, and ease of administration in settings with limited healthcare infrastructure. We plan to test this hypothesis in a randomized controlled trial (ClinicalTrials.gov Identifier: NCT01255215).
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Affiliation(s)
- Michael Hawkes
- Sandra A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University Health Network-Toronto General Hospital, University of Toronto, Toronto, Ontario, Canada
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70
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Hawkes M, Opoka RO, Namasopo S, Miller C, Thorpe KE, Lavery JV, Conroy AL, Liles WC, John CC, Kain KC. Inhaled nitric oxide for the adjunctive therapy of severe malaria: protocol for a randomized controlled trial. Trials 2011; 12:176. [PMID: 21752262 PMCID: PMC3151218 DOI: 10.1186/1745-6215-12-176] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 07/13/2011] [Indexed: 12/22/2022] Open
Abstract
Background Severe malaria remains a major cause of global morbidity and mortality. Despite the use of potent anti-parasitic agents, the mortality rate in severe malaria remains high. Adjunctive therapies that target the underlying pathophysiology of severe malaria may further reduce morbidity and mortality. Endothelial activation plays a central role in the pathogenesis of severe malaria, of which angiopoietin-2 (Ang-2) has recently been shown to function as a key regulator. Nitric oxide (NO) is a major inhibitor of Ang-2 release from endothelium and has been shown to decrease endothelial inflammation and reduce the adhesion of parasitized erythrocytes. Low-flow inhaled nitric oxide (iNO) gas is a US FDA-approved treatment for hypoxic respiratory failure in neonates. Methods/Design This prospective, parallel arm, randomized, placebo-controlled, blinded clinical trial compares adjunctive continuous inhaled nitric oxide at 80 ppm to placebo (both arms receiving standard anti-malarial therapy), among Ugandan children aged 1-10 years of age with severe malaria. The primary endpoint is the longitudinal change in Ang-2, an objective and quantitative biomarker of malaria severity, which will be analysed using a mixed-effects linear model. Secondary endpoints include mortality, recovery time, parasite clearance and neurocognitive sequelae. Discussion Noteworthy aspects of this trial design include its efficient sample size supported by a computer simulation study to evaluate statistical power, meticulous attention to complex ethical issues in a cross-cultural setting, and innovative strategies for safety monitoring and blinding to treatment allocation in a resource-constrained setting in sub-Saharan Africa. Trial Registration ClinicalTrials.gov Identifier: NCT01255215
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Affiliation(s)
- Michael Hawkes
- Institute of Medical Sciences, University of Toronto, Canada
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71
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Cserti-Gazdewich CM, Mayr WR, Dzik WH. Plasmodium falciparum malaria and the immunogenetics of ABO, HLA, and CD36 (platelet glycoprotein IV). Vox Sang 2011; 100:99-111. [PMID: 21175660 DOI: 10.1111/j.1423-0410.2010.01429.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Plasmodium falciparum malaria has long been a killer of the young, and has selected for polymorphisms affecting not only erythrocytes, but the immunogenetics of three histocompatibility systems: ABO, human leukocyte antigen (HLA), and CD36. The ABO system is important because the original allele, encoding glycosylation with the A sugar, acts as an adhesion ligand with infected red blood cells (iRBC), thereby promoting vasoocclusion. The prevalence of blood group O, which reduces this cytoadhesion, has increased in endemic areas. Other adaptations which could mitigate A-mediated rosetting include weaker A expression and increased soluble A secretion. The role of the HLA system in malaria has been harder to verify. Although HLA-B53 and DRB1*04 may be associated with clinical outcome, HLA studies are challenged by numerous comparisons in this most polymorphic of systems, and confounded by increasingly heterogeneous populations. Certain HLA markers may also reflect linkage artefact with other malaria-relevant polymorphisms. HLA may be less important because the parasite predominantly invades a compartment which does not express HLA. Adhesion of iRBCs is also mediated by CD36, expressed on platelets, monocytes, and microvascular endothelium. CD36 on monocytes is involved in clearing iRBC, while CD36 on platelets and the endothelium may play a role in tissue sequestration. The genetics of CD36 expression are complex, and recent research is fraught with inconsistent results. The solution may lie in examining genotype-phenotype correlations, zygosity effects on differential tissue expression, or other mechanisms altering CD36 tissue expression. Carefully designed prospective studies should bridge the gap between in-vitro observations and clinical outcomes.
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Affiliation(s)
- C M Cserti-Gazdewich
- Department of Medicine (Hematology), University Health Network/Toronto General Hospital, Toronto, ON,
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72
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Erdman LK, Dhabangi A, Musoke C, Conroy AL, Hawkes M, Higgins S, Rajwans N, Wolofsky KT, Streiner DL, Liles WC, Cserti-Gazdewich CM, Kain KC. Combinations of host biomarkers predict mortality among Ugandan children with severe malaria: a retrospective case-control study. PLoS One 2011; 6:e17440. [PMID: 21364762 PMCID: PMC3045453 DOI: 10.1371/journal.pone.0017440] [Citation(s) in RCA: 121] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 02/02/2011] [Indexed: 01/17/2023] Open
Abstract
Background Severe malaria is a leading cause of childhood mortality in Africa. However, at presentation, it is difficult to predict which children with severe malaria are at greatest risk of death. Dysregulated host inflammatory responses and endothelial activation play central roles in severe malaria pathogenesis. We hypothesized that biomarkers of these processes would accurately predict outcome among children with severe malaria. Methodology/Findings Plasma was obtained from children with uncomplicated malaria (n = 53), cerebral malaria (n = 44) and severe malarial anemia (n = 59) at time of presentation to hospital in Kampala, Uganda. Levels of angiopoietin-2, von Willebrand Factor (vWF), vWF propeptide, soluble P-selectin, soluble intercellular adhesion molecule-1 (ICAM-1), soluble endoglin, soluble FMS-like tyrosine kinase-1 (Flt-1), soluble Tie-2, C-reactive protein, procalcitonin, 10 kDa interferon gamma-induced protein (IP-10), and soluble triggering receptor expressed on myeloid cells-1 (TREM-1) were determined by ELISA. Receiver operating characteristic (ROC) curve analysis was used to assess predictive accuracy of individual biomarkers. Six biomarkers (angiopoietin-2, soluble ICAM-1, soluble Flt-1, procalcitonin, IP-10, soluble TREM-1) discriminated well between children who survived severe malaria infection and those who subsequently died (area under ROC curve>0.7). Combinational approaches were applied in an attempt to improve accuracy. A biomarker score was developed based on dichotomization and summation of the six biomarkers, resulting in 95.7% (95% CI: 78.1–99.9) sensitivity and 88.8% (79.7–94.7) specificity for predicting death. Similar predictive accuracy was achieved with models comprised of 3 biomarkers. Classification tree analysis generated a 3-marker model with 100% sensitivity and 92.5% specificity (cross-validated misclassification rate: 15.4%, standard error 4.9%). Conclusions We identified novel host biomarkers of pediatric severe and fatal malaria (soluble TREM-1 and soluble Flt-1) and generated simple biomarker combinations that accurately predicted death in an African pediatric population. While requiring validation in further studies, these results suggest the utility of combinatorial biomarker strategies as prognostic tests for severe malaria.
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Affiliation(s)
- Laura K. Erdman
- S.A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, Toronto General Hospital-University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Aggrey Dhabangi
- Makerere University College of Health Sciences, Kampala, Uganda
| | - Charles Musoke
- Makerere University College of Health Sciences, Kampala, Uganda
| | - Andrea L. Conroy
- S.A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, Toronto General Hospital-University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Michael Hawkes
- S.A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, Toronto General Hospital-University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Sarah Higgins
- S.A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, Toronto General Hospital-University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Nimerta Rajwans
- S.A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, Toronto General Hospital-University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Kayla T. Wolofsky
- School of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - David L. Streiner
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - W. Conrad Liles
- S.A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, Toronto General Hospital-University Health Network, University of Toronto, Toronto, Ontario, Canada
- Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, Toronto General Hospital, Toronto, Ontario, Canada
| | - Christine M. Cserti-Gazdewich
- Laboratory Medicine Program (Transfusion Medicine), University Health Network/University of Toronto, Toronto, Ontario, Canada
| | - Kevin C. Kain
- S.A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, Toronto General Hospital-University Health Network, University of Toronto, Toronto, Ontario, Canada
- Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, Toronto General Hospital, Toronto, Ontario, Canada
- * E-mail:
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73
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Conroy AL, Phiri H, Hawkes M, Glover S, Mallewa M, Seydel KB, Taylor TE, Molyneux ME, Kain KC. Endothelium-based biomarkers are associated with cerebral malaria in Malawian children: a retrospective case-control study. PLoS One 2010; 5:e15291. [PMID: 21209923 PMCID: PMC3012131 DOI: 10.1371/journal.pone.0015291] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 11/10/2010] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Differentiating cerebral malaria (CM) from other causes of serious illness in African children is problematic, owing to the non-specific nature of the clinical presentation and the high prevalence of incidental parasitaemia. CM is associated with endothelial activation. In this study we tested the hypothesis that endothelium-derived biomarkers are associated with the pathophysiology of severe malaria and may help identify children with CM. METHODS AND FINDINGS Plasma samples were tested from children recruited with uncomplicated malaria (UM; n = 32), cerebral malaria with retinopathy (CM-R; n = 38), clinically defined CM without retinopathy (CM-N; n = 29), or non-malaria febrile illness with decreased consciousness (CNS; n = 24). Admission levels of angiopoietin-2 (Ang-2), Ang-1, soluble Tie-2 (sTie-2), von Willebrand factor (VWF), its propeptide (VWFpp), vascular endothelial growth factor (VEGF), soluble ICAM-1 (sICAM-1) and interferon-inducible protein 10 (IP-10) were measured by ELISA. Children with CM-R had significantly higher median levels of Ang-2, Ang-2:Ang-1, sTie-2, VWFpp and sICAM-1 compared to children with CM-N. Children with CM-R had significantly lower median levels of Ang-1 and higher median concentrations of Ang-2:Ang-1, sTie-2, VWF, VWFpp, VEGF and sICAM-1 compared to UM, and significantly lower median levels of Ang-1 and higher median levels of Ang-2, Ang-2:Ang-1, VWF and VWFpp compared to children with fever and altered consciousness due to other causes. Ang-1 was the best discriminator between UM and CM-R and between CNS and CM-R (areas under the ROC curve of 0.96 and 0.93, respectively). A comparison of biomarker levels in CM-R between admission and recovery showed uniform increases in Ang-1 levels, suggesting this biomarker may have utility in monitoring clinical response. CONCLUSIONS These results suggest that endothelial proteins are informative biomarkers of malarial disease severity. These results require validation in prospective studies to confirm that this group of biomarkers improves the diagnostic accuracy of CM from similar conditions causing fever and altered consciousness.
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Affiliation(s)
- Andrea L. Conroy
- Sandra A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, University Health Network-Toronto General Hospital, University of Toronto, Toronto, Canada
| | - Happy Phiri
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
| | - Michael Hawkes
- Sandra A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, University Health Network-Toronto General Hospital, University of Toronto, Toronto, Canada
| | - Simon Glover
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Mac Mallewa
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- School of Tropical Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Karl B. Seydel
- Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi
- Department of Internal Medicine, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, United States of America
| | - Terrie E. Taylor
- Blantyre Malaria Project, College of Medicine, University of Malawi, Blantyre, Malawi
- Department of Internal Medicine, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, United States of America
| | - Malcolm E. Molyneux
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- College of Medicine, University of Malawi, Blantyre, Malawi
- School of Tropical Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Kevin C. Kain
- Sandra A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, University Health Network-Toronto General Hospital, University of Toronto, Toronto, Canada
- Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, Canada
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Peyvandi F, Hollestelle MJ, Palla R, Merlini PA, Feys HB, Vanhoorelbeke K, Lenting PJ, Mannucci PM. Active platelet-binding conformation of plasma von Willebrand factor in young women with acute myocardial infarction. J Thromb Haemost 2010; 8:1653-6. [PMID: 20456747 DOI: 10.1111/j.1538-7836.2010.03896.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ghafoor SZA, MacRae EA, Harding KG, Patel GK. Symmetrical peripheral digital gangrene following severe Plasmodium falciparum malaria-induced disseminated intravascular coagulopathy. Int Wound J 2010; 7:418-22. [PMID: 20586820 DOI: 10.1111/j.1742-481x.2010.00697.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Symmetrical peripheral digital gangrene is a life-changing complication, caused by a pro-thrombotic life-threatening disease, such as disseminated intravascular coagulopathy (DIC) secondary to systemic infection. We describe the unusual case of a woman who developed symmetrical peripheral digital gangrene following DIC because of malaria. While initial treatment led to cure of the infection, in this report we describe also the subsequent management of symmetrical peripheral digital gangrene.
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Affiliation(s)
- Sana Z A Ghafoor
- Department of Dermatology and Wound Healing, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK
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Abstract
In this issue of Blood, Bridges and colleagues report that Plasmodium falciparum-infected erythrocytes are able to attach to the endothelial surface by binding platelet-decorated VWF strands in a CD36-dependent fashion, revealing a new mechanism for erythrocyte cytoadherence in malaria.(1).
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Bridges DJ, Bunn J, van Mourik JA, Grau G, Preston RJS, Molyneux M, Combes V, O'Donnell JS, de Laat B, Craig A. Rapid activation of endothelial cells enables Plasmodium falciparum adhesion to platelet-decorated von Willebrand factor strings. Blood 2010; 115:1472-4. [PMID: 19897581 PMCID: PMC2840836 DOI: 10.1182/blood-2009-07-235150] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During Plasmodium falciparum malaria infections, von Willebrand factor (VWF) levels are elevated, postmortem studies show platelets colocalized with sequestered infected erythrocytes (IEs) at brain microvascular sites, whereas in vitro studies have demonstrated platelet-mediated IE adhesion to tumor necrosis factor-activated brain endothelium via a bridging mechanism. This current study demonstrates how all these observations could be linked through a completely novel mechanism whereby IEs adhere via platelet decorated ultra-large VWF strings on activated endothelium. Using an in vitro laminar flow model, we have demonstrated tethering and firm adhesion of IEs to the endothelium specifically at sites of platelet accumulation. We also show that an IE pro-adhesive state, capable of supporting high levels of binding within minutes of induction, can be removed through the action of the VWF protease ADAMTS-13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13). We propose that this new mechanism contributes to sequestration both independently of and in concert with current adhesion mechanisms.
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Affiliation(s)
- Daniel J Bridges
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom.
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Cox D, McConkey S. The role of platelets in the pathogenesis of cerebral malaria. Cell Mol Life Sci 2010; 67:557-68. [PMID: 20091081 PMCID: PMC11115904 DOI: 10.1007/s00018-009-0211-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 11/05/2009] [Indexed: 01/31/2023]
Abstract
Malaria is a major cause of morbidity and mortality in the developing world and cerebral malaria is responsible for the majority of malaria-associated deaths. There is a strong association between thrombocytopenia and outcome in malaria, suggesting a role for platelets in the pathogenesis of malaria. This thrombocytopenia is likely due to platelet activation possibly through an interaction between PfEMP1 on plasmodium and CD36 on platelets. Platelet activation by plasmodium has two potential consequences. It can lead to the formation of micro-aggregates of infected red blood cells and platelets which can occlude blood vessels and it also leads to binding to and activation of the endothelium.
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Affiliation(s)
- Dermot Cox
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St Stephens Green, Dublin 2, Ireland.
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Nieman AE, de Mast Q, Roestenberg M, Wiersma J, Pop G, Stalenhoef A, Druilhe P, Sauerwein R, van der Ven A. Cardiac complication after experimental human malaria infection: a case report. Malar J 2009; 8:277. [PMID: 19958549 PMCID: PMC2794284 DOI: 10.1186/1475-2875-8-277] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 12/03/2009] [Indexed: 02/07/2023] Open
Abstract
A 20 year-old healthy female volunteer participated in a clinical Phase I and IIa safety and efficacy trial with candidate malaria vaccine PfLSA-3-rec adjuvanted with aluminium hydroxide. Eleven weeks after the third and last immunization she was experimentally infected by bites of Plasmodium falciparum-infected mosquitoes. When the thick blood smear became positive, at day 11, she was treated with artemether/lumefantrine according to protocol. On day 16 post-infection i.e. two days after completion of treatment, she woke up with retrosternal chest pain. She was diagnosed as acute coronary syndrome and treated accordingly. She recovered quickly and her follow-up was uneventful. Whether the event was related to the study procedures such as the preceding vaccinations, malaria infection or antimalarial drugs remains elusive. However, the relation in time with the experimental malaria infection and apparent absence of an underlying condition makes the infection the most probable trigger. This is in striking contrast, however, with the millions of malaria cases each year and the fact that such complication has never been reported in the literature. The rare occurrence of cardiac events with any of the preceding study procedures may even support a coincidental finding. Apart from acute coronary syndrome, myocarditis can be considered as a final diagnosis, but the true nature and patho-physiological explanation of the event remain unclear.
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Affiliation(s)
- An-Emmie Nieman
- Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
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80
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Moxon CA, Heyderman RS, Wassmer SC. Dysregulation of coagulation in cerebral malaria. Mol Biochem Parasitol 2009; 166:99-108. [PMID: 19450727 PMCID: PMC2724037 DOI: 10.1016/j.molbiopara.2009.03.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 03/12/2009] [Accepted: 03/13/2009] [Indexed: 12/27/2022]
Abstract
Cerebral malaria (CM) is a life-threatening complication of Plasmodium falciparum infection and represents a major cause of morbidity and mortality worldwide. The nature of the pathogenetic processes leading to the cerebral complications remains poorly understood. It has recently emerged that in addition to their conventional role in the regulation of haemostasis, coagulation factors have an inflammatory role that is pivotal in the pathogenesis of a number of acute and chronic conditions, including CM. This new insight offers important therapeutic potential. This review explores the clinical, histological and molecular evidence for the dysregulation of the coagulation system in CM, looking at possible underlying mechanisms. We discuss areas for future research to improve understanding of CM pathogenesis and for the development of new therapeutic approaches.
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Affiliation(s)
- Christopher Alan Moxon
- Malawi Liverpool Wellcome Trust Clinical Research Programme, College of Medicine, Chichiri, PO Box 30096, Blantyre 3, Malawi.
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81
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Lovegrove FE, Tangpukdee N, Opoka RO, Lafferty EI, Rajwans N, Hawkes M, Krudsood S, Looareesuwan S, John CC, Liles WC, Kain KC. Serum angiopoietin-1 and -2 levels discriminate cerebral malaria from uncomplicated malaria and predict clinical outcome in African children. PLoS One 2009; 4:e4912. [PMID: 19300530 PMCID: PMC2657207 DOI: 10.1371/journal.pone.0004912] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2008] [Accepted: 02/05/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Limited tools exist to identify which individuals infected with Plasmodium falciparum are at risk of developing serious complications such as cerebral malaria (CM). The objective of this study was to assess serum biomarkers that differentiate between CM and non-CM, with the long-term goal of developing a clinically informative prognostic test for severe malaria. METHODOLOGY/PRINCIPAL FINDINGS Based on the hypothesis that endothelial activation and blood-brain-barrier dysfunction contribute to CM pathogenesis, we examined the endothelial regulators, angiopoietin-1 (ANG-1) and angiopoietin-2 (ANG-2), in serum samples from P. falciparum-infected patients with uncomplicated malaria (UM) or CM, from two diverse populations--Thai adults and Ugandan children. Angiopoietin levels were compared to tumour necrosis factor (TNF). In both populations, ANG-1 levels were significantly decreased and ANG-2 levels were significantly increased in CM versus UM and healthy controls (p<0.001). TNF was significantly elevated in CM in the Thai adult population (p<0.001), but did not discriminate well between CM and UM in African children. Receiver operating characteristic curve analysis showed that ANG-1 and the ratio of ANG-2:ANG-1 accurately discriminated CM patients from UM in both populations. Applied as a diagnostic test, ANG-1 had a sensitivity and specificity of 100% for distinguishing CM from UM in Thai adults and 70% and 75%, respectively, for Ugandan children. Across both populations the likelihood ratio of CM given a positive test (ANG-1<15 ng/mL) was 4.1 (2.7-6.5) and the likelihood ratio of CM given a negative test was 0.29 (0.20-0.42). Moreover, low ANG-1 levels at presentation predicted subsequent mortality in children with CM (p = 0.027). CONCLUSIONS/SIGNIFICANCE ANG-1 and the ANG-2/1 ratio are promising clinically informative biomarkers for CM. Additional studies should address their utility as prognostic biomarkers and potential therapeutic targets in severe malaria.
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Affiliation(s)
- Fiona E. Lovegrove
- McLaughlin-Rotman Centre for Global Health, McLaughlin Centre for Molecular Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | | | - Robert O. Opoka
- Department of Paediatrics and Child Health, Makerere University, Kampala, Uganda
| | - Erin I. Lafferty
- McLaughlin-Rotman Centre for Global Health, McLaughlin Centre for Molecular Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Nimerta Rajwans
- McLaughlin-Rotman Centre for Global Health, McLaughlin Centre for Molecular Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Michael Hawkes
- McLaughlin-Rotman Centre for Global Health, McLaughlin Centre for Molecular Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Chandy C. John
- Department of Pediatrics, University of Minnesota Medical School, Minneapolis, Minnesota, United States of America
| | - W. Conrad Liles
- McLaughlin-Rotman Centre for Global Health, McLaughlin Centre for Molecular Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Kevin C. Kain
- McLaughlin-Rotman Centre for Global Health, McLaughlin Centre for Molecular Medicine, University Health Network, University of Toronto, Toronto, Ontario, Canada
- Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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82
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Larkin D, de Laat B, Jenkins PV, Bunn J, Craig AG, Terraube V, Preston RJS, Donkor C, Grau GE, van Mourik JA, O'Donnell JS. Severe Plasmodium falciparum malaria is associated with circulating ultra-large von Willebrand multimers and ADAMTS13 inhibition. PLoS Pathog 2009; 5:e1000349. [PMID: 19300493 PMCID: PMC2652105 DOI: 10.1371/journal.ppat.1000349] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 02/25/2009] [Indexed: 11/23/2022] Open
Abstract
Plasmodium falciparum infection results in adhesion of infected erythrocytes to blood vessel endothelium, and acute endothelial cell activation, together with sequestration of platelets and leucocytes. We have previously shown that patients with severe infection or fulminant cerebral malaria have significantly increased circulatory levels of the adhesive glycoprotein von Willebrand factor (VWF) and its propeptide, both of which are indices of endothelial cell activation. In this prospective study of patients from Ghana with severe (n = 20) and cerebral (n = 13) P. falciparum malaria, we demonstrate that increased plasma VWF antigen (VWF:Ag) level is associated with disproportionately increased VWF function. VWF collagen binding (VWF:CB) was significantly increased in patients with cerebral malaria and severe malaria (medians 7.6 and 7.0 IU/ml versus 1.9 IU/ml; p<0.005). This increased VWF:CB correlated with the presence of abnormal ultra-large VWF multimers in patient rather than control plasmas. Concomitant with the increase in VWF:Ag and VWF:CB was a significant persistent reduction in the activity of the VWF-specific cleaving protease ADAMTS13 (approximately 55% of normal; p<0.005). Mixing studies were performed using P. falciparum patient plasma and normal pooled plasma, in the presence or absence of exogenous recombinant ADAMTS13. These studies demonstrated that in malarial plasma, ADAMTS13 function was persistently inhibited in a time-dependent manner. Furthermore, this inhibitory effect was not associated with the presence of known inhibitors of ADAMTS13 enzymatic function (interleukin-6, free haemoglobin, factor VIII or thrombospondin-1). These novel findings suggest that severe P. falciparum infection is associated with acute endothelial cell activation, abnormal circulating ULVWF multimers, and a significant reduction in plasma ADAMTS13 function which is mediated at least in part by an unidentified inhibitor.
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Affiliation(s)
- Deirdre Larkin
- Haemostasis Research Group, Trinity Centre for Health Sciences, Trinity College Dublin, Dublin, Ireland
| | | | - P. Vince Jenkins
- Haemostasis Research Group, Trinity Centre for Health Sciences, Trinity College Dublin, Dublin, Ireland
| | - James Bunn
- Departments of Community Health and Paediatrics, College of Medicine, Blantyre, Malawi
- School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Virginie Terraube
- Haemostasis Research Group, Trinity Centre for Health Sciences, Trinity College Dublin, Dublin, Ireland
| | - Roger J. S. Preston
- Haemostasis Research Group, Trinity Centre for Health Sciences, Trinity College Dublin, Dublin, Ireland
| | - Cynthia Donkor
- School of Tropical Medicine, Liverpool, United Kingdom
- Komfo Anokye Teaching Hospital, Kumasi, Ghana
| | - George E. Grau
- Department of Pathology, University of Sydney, Sydney, New South Wales, Australia
| | | | - James S. O'Donnell
- Haemostasis Research Group, Trinity Centre for Health Sciences, Trinity College Dublin, Dublin, Ireland
- National Centre for Hereditary Coagulation Disorders, St James's Hospital, Dublin, Ireland
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83
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Boivin MJ, Giordani B. Neuropsychological assessment of African children: evidence for a universal brain/behavior omnibus within a coconstructivist paradigm. PROGRESS IN BRAIN RESEARCH 2009; 178:113-35. [PMID: 19874965 DOI: 10.1016/s0079-6123(09)17808-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cross-cultural neuropsychology with African and American children provides evidence of consistent deficit patterns in attention, working memory, and learning in children at risk from disease affecting brain function by means of similar pathophysiologic mechanisms (e.g., cerebral malaria (CM) and sickle-cell disease (SCD); HIV in African and American children). These brain-behavior disease processes are also modified in a consistent manner cross-culturally by quality of developmental milieu and caregiving. We then present findings from the pioneering use of computerized cognitive rehabilitation therapy (CCRT) with Ugandan children surviving CM and with HIV. This neuropsychological evidence that CCRT enhances positive brain plasticity in a consistent manner across cultures supports the "coconstructive" paradigm (Li, 2003), since plasticity across the life span is the hallmark of this approach. Coconstructivism is a holistic multi-dimensional approach that emphasizes reciprocal biocultural influences across the life span. It also emphasizes the reciprocal interaction of culture and the genome in shaping brain/mind at multiple levels: neurobiological, cognitively, behavioral, and sociocultural (Li, 2003). Cross-cultural neuropsychology in healthy and diseased brains, brain imaging technologies, and genomic research can triangulate the manner in which a universal brain/behavior omnibus drives plasticity across the life span. As such, the further scientific characterization of the brain/behavior omnibus can provide the vital lynchpin between biology and culture in Li's coconstructive paradigm, revolutionizing our understanding of intelligence and culture.
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Affiliation(s)
- Michael J Boivin
- International Neurologic and Psychiatric Epidemiology Program, Michigan State University, East Lansing, MI, USA.
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84
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Angiopoietin-2 is associated with decreased endothelial nitric oxide and poor clinical outcome in severe falciparum malaria. Proc Natl Acad Sci U S A 2008; 105:17097-102. [PMID: 18957536 DOI: 10.1073/pnas.0805782105] [Citation(s) in RCA: 213] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Adherence of parasitized erythrocytes to activated endothelium causes microvascular obstruction, tissue ischemia, and clinical complications in severe malaria (SM); however, the mechanisms leading to endothelial activation remain unclear. The angiogenic factors, angiopoietin-2 (Ang-2) and vascular endothelial growth factor (VEGF) are modulators of endothelial activation, with Ang-2 release from Weibel-Palade bodies (WPBs) being regulated by endothelial nitric oxide (NO). We explored the relationships between endothelial NO bioavailability, Ang-2, VEGF, tissue perfusion, and clinical outcomes in SM. We measured plasma Ang-2 and VEGF, together with biomarkers of severity from 146 adults with and without SM, in parallel with longitudinal measures of endothelial function by using reactive hyperemia peripheral arterial tonometry (a measure of endothelial NO bioavailability). Regression was used to relate concentrations of Ang-2/VEGF with malaria disease severity, biomarkers of perfusion, endothelial activation, and parasite biomass. The longitudinal relationship between Ang-2 and endothelial function was assessed by using a mixed-effects model. Ang-2 concentrations were elevated in SM and associated with increased venous lactate, plasma intercellular cell adhesion molecule-1 concentrations, parasite biomass, and mortality. In contrast, VEGF concentrations were inversely associated with these biomarkers. Ang-2 concentrations were significantly better predictors of death than venous lactate (P = 0.03). Recovery of endothelial function was associated with falling concentrations of Ang-2. Ang-2 release from endothelial cells with reduced NO bioavailability is likely to contribute to endothelial activation, sequestered parasite biomass, impaired perfusion, and poor outcome in severe falciparum malaria. Agents that improve endothelial NO, reduce WPB exocytosis, and/or antagonize Ang-2 may have therapeutic roles in SM.
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85
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Patel SN, Berghout J, Lovegrove FE, Ayi K, Conroy A, Serghides L, Min-oo G, Gowda DC, Sarma JV, Rittirsch D, Ward PA, Liles WC, Gros P, Kain KC. C5 deficiency and C5a or C5aR blockade protects against cerebral malaria. J Exp Med 2008; 205:1133-43. [PMID: 18426986 PMCID: PMC2373845 DOI: 10.1084/jem.20072248] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 04/02/2008] [Indexed: 12/13/2022] Open
Abstract
Experimental infection of mice with Plasmodium berghei ANKA (PbA) provides a powerful model to define genetic determinants that regulate the development of cerebral malaria (CM). Based on the hypothesis that excessive activation of the complement system may confer susceptibility to CM, we investigated the role of C5/C5a in the development of CM. We show a spectrum of susceptibility to PbA in a panel of inbred mice; all CM-susceptible mice examined were found to be C5 sufficient, whereas all C5-deficient strains were resistant to CM. Transfer of the C5-defective allele from an A/J (CM resistant) onto a C57BL/6 (CM-susceptible) genetic background in a congenic strain conferred increased resistance to CM; conversely, transfer of the C5-sufficient allele from the C57BL/6 onto the A/J background recapitulated the CM-susceptible phenotype. The role of C5 was further explored in B10.D2 mice, which are identical for all loci other than C5. C5-deficient B10.D2 mice were protected from CM, whereas C5-sufficient B10.D2 mice were susceptible. Antibody blockade of C5a or C5a receptor (C5aR) rescued susceptible mice from CM. In vitro studies showed that C5a-potentiated cytokine secretion induced by the malaria product P. falciparum glycosylphosphatidylinositol and C5aR blockade abrogated these amplified responses. These data provide evidence implicating C5/C5a in the pathogenesis of CM.
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Affiliation(s)
- Samir N Patel
- Tropical Disease Unit, Department of Medicine, McLaughlin-Rotman Centre for Global Health, Toronto General Hospital, Toronto, Ontario M5G 2C4, Canada
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86
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Metcalf DJ, Nightingale TD, Zenner HL, Lui-Roberts WW, Cutler DF. Formation and function of Weibel-Palade bodies. J Cell Sci 2008; 121:19-27. [PMID: 18096688 DOI: 10.1242/jcs.03494] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Weibel-Palade bodies (WPBs) are secretory organelles used for post-synthesis storage in endothelial cells that can, very rapidly, be triggered to release their contents. They carry a variety of bioactive molecules that are needed to mount a rapid response to the complex environment of cells that line blood vessels. They store factors that are essential to haemostasis and inflammation, as well as factors that modulate vascular tonicity and angiogenesis. The number of WPBs and their precise content vary between endothelial tissues, reflecting their differing physiological circumstances. The particular functional demands of the highly multimerised haemostatic protein von Willebrand Factor (VWF), which is stored in WPBs as tubules until release, are responsible for the cigar shape of these granules. How VWF tubules drive the formation of these uniquely shaped organelles, and how WPB density increases during maturation, has recently been revealed by EM analysis using high-pressure freezing and freeze substitution. In addition, an AP1/clathrin coat has been found to be essential to WPB formation. Following recruitment of cargo at the TGN, there is a second wave of recruitment that delivers integral and peripheral membrane proteins to WPBs, some of which is AP3 dependent.
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Affiliation(s)
- Daniel J Metcalf
- MRC Laboratory of Molecular Cell Biology, Cell Biology Unit, University College London, Gower Street, London, WC1E 6BT, UK
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87
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Francischetti IMB, Seydel KB, Monteiro RQ. Blood coagulation, inflammation, and malaria. Microcirculation 2008; 15:81-107. [PMID: 18260002 DOI: 10.1080/10739680701451516] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Malaria remains a highly prevalent disease in more than 90 countries and accounts for at least 1 million deaths every year. Plasmodium falciparum infection is often associated with a procoagulant tonus characterized by thrombocytopenia and activation of the coagulation cascade and fibrinolytic system; however, bleeding and hemorrhage are uncommon events, suggesting that a compensated state of blood coagulation activation occurs in malaria. This article (i) reviews the literature related to blood coagulation and malaria in a historic perspective, (ii) describes basic mechanisms of coagulation, anticoagulation, and fibrinolysis, (iii) explains the laboratory changes in acute and compensated disseminated intravascular coagulation (DIC), (iv) discusses the implications of tissue factor (TF) expression in the endothelium of P. falciparum infected patients, and (v) emphasizes the procoagulant role of parasitized red blood cells (RBCs) and activated platelets in the pathogenesis of malaria. This article also presents the Tissue Factor Model (TFM) for malaria pathogenesis, which places TF as the interface between sequestration, endothelial cell (EC) activation, blood coagulation disorder, and inflammation often associated with the disease. The relevance of the coagulation-inflammation cycle for the multiorgan dysfunction and coma is discussed in the context of malaria pathogenesis.
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Affiliation(s)
- Ivo M B Francischetti
- Vector Biology Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-8132, USA.
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88
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Chung MC, Popova TG, Jorgensen SC, Dong L, Chandhoke V, Bailey CL, Popov SG. Degradation of circulating von Willebrand factor and its regulator ADAMTS13 implicates secreted Bacillus anthracis metalloproteases in anthrax consumptive coagulopathy. J Biol Chem 2008; 283:9531-42. [PMID: 18263586 DOI: 10.1074/jbc.m705871200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pathology data from the anthrax animal models show evidence of significant increases in vascular permeability coincident with hemostatic imbalances manifested by thrombocytopenia, transient leucopenia, and aggressive disseminated intravascular coagulation. In this study we hypothesized that anthrax infection modulates the activity of von Willebrand factor (VWF) and its endogenous regulator ADAMTS13, which play important roles in hemostasis and thrombosis, including interaction of endothelial cells with platelets. We previously demonstrated that purified anthrax neutral metalloproteases Npr599 and InhA are capable of cleaving a variety of host structural and regulatory proteins. Incubation of human plasma with these proteases at 37 degrees C in the presence of urea as a mild denaturant results in proteolysis of VWF. Also in these conditions, InhA directly cleaves plasma ADAMTS13 protein. Npr599 and InhA digest synthetic VWF substrate FRETS-VWF73. Amino acid sequencing of VWF fragments produced by InhA suggests that one of the cleavage sites of VWF is located at domain A2, the target domain of ADAMTS13. Proteolysis of VWF by InhA impairs its collagen binding activity (VWF:CBA) and ristocetin-induced platelet aggregation activity. In plasma from anthrax spore-challenged DBA/2 mice, VWF antigen levels increase up to 2-fold at day 3 post-infection with toxigenic Sterne 34F(2) strain, whereas VWF:CBA levels drop in a time-dependent manner, suggesting dysfunction of VWF instead of its quantitative deficiency. This conclusion is further supported by significant reduction in the amount of VWF circulating in blood in the ultra-large forms. In addition, Western blot analysis shows proteolytic depletion of ADAMTS13 from plasma of spore-challenged mice despite its increased expression in the liver. Our results suggest a new mechanism of anthrax coagulopathy affecting the levels and functional activities of both VWF and its natural regulator ADAMTS13. This mechanism may contribute to hemorrhage and thrombosis typical in anthrax.
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Affiliation(s)
- Myung-Chul Chung
- National Center for Biodefense and Infectious Diseases, College of Sciences, George Mason University, 10900 University Boulevard, Manassas, VA 20110, USA
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89
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Silver KL, Kain KC, Liles WC. Endothelial activation and dysregulation: A common pathway to organ injury in infectious diseases associated with systemic inflammation. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.ddmec.2008.01.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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90
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Lippi G, Franchini M, Targher G, Poli G, Guidi GC. The significance of evaluating conventional inflammatory markers in Von Willebrand factor measurement. Clin Chim Acta 2007; 381:167-70. [PMID: 17433810 DOI: 10.1016/j.cca.2007.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2007] [Revised: 03/06/2007] [Accepted: 03/06/2007] [Indexed: 11/16/2022]
Abstract
BACKGROUND The appropriate clinical interpretation of Von Willebrand factor (VWF) measurements is crucial since inherited or acquired deficiencies are responsible for a potentially life threatening bleeding disorder, whereas increased plasma concentrations may be associated with an increased thrombotic risk. Besides age and blood group, the variability introduced by the presence of an acute phase response might contribute to decrease the clinical usefulness of this measurement. METHODS To investigate the relationship between conventional inflammatory markers and VWF, 387 consecutive unselected patients undergoing surgical procedures at our University Hospital were systematically investigated for routine laboratory testing, including also VWF Antigen (VWF:Ag), C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) as parts of a routine preoperative screening program. RESULTS After stratifying the study population according to the upper limit of the reference range of the two inflammatory markers, a significantly increased median VWF:Ag plasma concentration was observed for subjects with increased value of both CRP (CRP>5 mg/L=VWF:Ag>120 UI/dL; CRP<5 mg/L=VWF:Ag 98 UI/dL, p=0.003) and ESR (ESR>30 mm/hg=VWF:Ag>120 UI/dL; ESR<30 mm/hg=VWF:Ag 96 UI/dL, p<0.001). A significantly different frequency distribution of VWF:Ag concentrations was also observed in subjects with values of inflammatory markers above the upper limits of the reference ranges when compared to those with normal values. In particular, the prevalence of subjects with VWF:Ag levels>120 UI/dL was six- and nearly three-times higher in subjects with abnormal values of CRP (55.8% versus 9.3%, p<0.001) and ESR (54.5% versus 18.7%, p<0.001), respectively. CONCLUSIONS Results of this investigation demonstrate that the evaluation of conventional inflammatory markers would represent a valuable tool to enhance the clinical usefulness of VWF measurements, especially in patients with transitory and subclinical inflammation. Since VWF and factor VIII are likely to increase in parallel, we suggest that their measurements should be repeated at least after 6 months to one year in the presence of concomitantly increased values of inflammatory markers, such as ESR and/or CRP.
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Affiliation(s)
- Giuseppe Lippi
- Sezione di Chimica e Microscopia Clinica, Dipartimento di Scienze Morfologico-Biomediche, Università degli Studi di Verona, Italy.
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91
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Groot E, de Groot PG, Fijnheer R, Lenting PJ. The presence of active von Willebrand factor under various pathological conditions. Curr Opin Hematol 2007; 14:284-9. [PMID: 17414220 DOI: 10.1097/moh.0b013e3280dce531] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
PURPOSE OF REVIEW To highlight mechanisms that regulate the balance between latent and active von Willebrand factor (VWF), and describe pathological conditions leading to increased levels of active VWF. RECENT FINDINGS Levels of circulating active VWF are increased in von Willebrand disease type 2B, HELLP syndrome, malaria and antiphospholipid syndrome. SUMMARY Freshly secreted VWF consists of ultra-large multimers that interact spontaneously with platelets at the endothelial cell surface. Proteolysis of ultra-large VWF by a member of the disintegrin and metalloprotease with thrombospondin motif family (ADAMTS13) reduces both multimeric size and accessibility of platelet-adhesion sites. The resulting VWF molecules circulate as inactive multimers, which regain their platelet-adhesion capacity upon binding to the subendothelial matrix, in particular under conditions of high shear. Unfortunately, mechanisms responsible for suppression of circulating plasma levels of active VWF are hampered in a number of pathological conditions, leading to VWF-platelet aggregates associated with thrombotic complications or thrombocytopenia. A recently developed assay allowed us to monitor the presence of circulating active VWF and we found that several diseases are characterized by increased levels. Further analysis provided insight into mechanisms contributing to the presence of active VWF, which revealed that beta2-glycoprotein I may act as a natural regulator of VWF-platelet interactions.
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Affiliation(s)
- Evelyn Groot
- Laboratory for Thrombosis and Haemostasis, Department of Clinical Chemistry & Haematology, University Medical Center Utrecht, The Netherlands
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92
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Abstract
In the century since the discovery of the ABO blood groups, numerous associations between ABO groups and disease have been noted. However, the selection pressures defining the ABO distributions remain uncertain. We review published information on Plasmodium falciparum infection and ABO blood groups. DNA sequence information dates the emergence and development of the group O allele to a period of evolution before human migration out of Africa, concomitant with P falciparum's activity. The current geographic distribution of group O is also consistent with a selection pressure by P falciparum in favor of group O individuals in malaria-endemic regions. We critically review clinical reports of ABO and P falciparum infection, documenting a correlation between disease severity and ABO group. Finally, we review published data on the pathogenesis of P falciparum infection, and propose a biologic model to summarize the role of ABO blood groups in cytoadherence biology. Such ABO-related mechanisms also point to a new hypothesis to account for selection of the Le(a-b-) phenotype. Taken together, a broad range of available evidence suggests that the origin, distribution, and relative proportion of ABO blood groups in humans may have been directly influenced by selective genetic pressure from P falciparum infection.
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Affiliation(s)
- Christine M Cserti
- University Health Network, Toronto General Hospital (Blood Transfusion Laboratory), Toronto, Ontario, Canada.
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93
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Uddenfeldt Wort U, Hastings I, Bergström S, Massawe S, Lipingu C, Brabin BJ. Increased postpartum blood loss in pregnancies associated with placental malaria. Int J Gynaecol Obstet 2007; 96:171-5. [PMID: 17280666 DOI: 10.1016/j.ijgo.2006.11.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Revised: 11/20/2006] [Accepted: 11/29/2006] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To determine the relationship of placental malaria and parity with postpartum blood loss in a malarious area of Tanzania. METHODS A total of 706 uncomplicated vaginal deliveries were studied at Muhimbili University Hospital, Dar es Salaam, Tanzania. Maternal age, parity, date of delivery, birth weight, presence of placental malaria, stillbirths, and delivery complications were noted. Collection and measurement of vaginal blood loss commenced immediately following birth using a plastic vinyl sheet placed underneath the mother. The bed was divided in the middle to allow the blood to drain into a bucket. Blood loss was measured for a period of 2 h following delivery. RESULTS In singleton births the mean postpartum blood loss was 170 mL in nulliparas and 187 mL in multiparas (p=0.017). Blood loss was 400 mL or greater in 23 women (3.4%) and 500 mL or greater in 10 women (1.5%). Mean postpartum bleeding tended to increase with maternal age, parity, and birth weight. In logistic regression the odds ratio for a blood loss of 400 mL or greater was significantly increased for women with placental malaria (3.2; 95% confidence interval, 1.1-9.0; p=0.028), after adjusting for a birth weight greater than 4000 g. Placental malaria showed a marked seasonal pattern, which corresponded to the months of peak prevalence for a postpartum blood loss of 400 mL or greater (p=0.007). CONCLUSION A postpartum blood loss of 400 mL or greater should be considered a possible complication of placental malaria.
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Affiliation(s)
- U Uddenfeldt Wort
- Division of International Health (IHCAR), Karolinska Institutet, Stockholm, Sweden
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94
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Loscertales M, Owens S, O'Donnell J, Bunn J, Bosch‐Capblanch X, Brabin BJ. ABO Blood Group Phenotypes and Plasmodium falciparum Malaria: Unlocking a Pivotal Mechanism. ADVANCES IN PARASITOLOGY 2007; 65:1-50. [DOI: 10.1016/s0065-308x(07)65001-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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95
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Affiliation(s)
- M V Ragni
- Department of Medicine, Division of Hematology and Oncology, University of Pittsburgh, and Hemophilia Center of Western PA, Pittsburgh, PA 15213, USA.
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96
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Taoufiq Z, Pino P, Dugas N, Conti M, Tefit M, Mazier D, Vouldoukis I. Transient supplementation of superoxide dismutase protects endothelial cells against Plasmodium falciparum-induced oxidative stress. Mol Biochem Parasitol 2006; 150:166-73. [PMID: 16930739 DOI: 10.1016/j.molbiopara.2006.07.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2006] [Revised: 07/11/2006] [Accepted: 07/17/2006] [Indexed: 11/19/2022]
Abstract
The pathogenesis of cerebral malaria, a major complication of Plasmodium falciparum infection, relies on mechanisms such as cytokine production and cytoadherence of parasitized red blood cells (PRBCs) on microvascular endothelial cells. In this way parasites avoid spleen clearance by sequestration in post-capillary venules of various organs including the brain. Infected erythrocytes adhesion has also been shown to have molecular signaling consequences providing insight on how tissue homeostasis could be comprised by endothelium perturbation. Our previous work demonstrated that PRBCs adhesion to human lung endothelial cells (HLEC) induces caspases activation, oxidative stress and apoptosis. Cytoplasmic Cu/Zn superoxide dismutase (SOD1), which provides the first line of defense against oxidative stress within a cell, is now used as a treatment of numerous diseases including traumatic brain injury and ischemic stroke. In this report, we demonstrated that transient supplementation of SOD1 protects endothelial cells against P. falciparum induced oxidative stress and apoptosis. We also showed a significant decrease in PRBCs cytoadherence through a downregulation of ICAM-1 and an induction of iNOS. Protection of endothelium via antioxidant delivery may constitute a relevant strategy in cerebral malaria treatment.
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Affiliation(s)
- Zacharie Taoufiq
- INSERM UMR511, Immunobiologie Cellulaire et Moléculaire des Infections Parasitaires, CHU Pitié-Salpêtrière, Université Pierre et Marie Curie, 91 bd de l'Hôpital, 75013 Paris, France.
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