1
|
Stins MF, Mtaja A, Mulendele E, Mwimbe DW, Pinilla G, Mutengo M, Pardo CA, Chipeta J. Elevated brain derived neurotrophic factor in plasma and interleukin-6 levels in cerebrospinal fluid in meningitis compared to cerebral malaria. J Neurol Sci 2023; 450:120663. [PMID: 37182424 PMCID: PMC10330544 DOI: 10.1016/j.jns.2023.120663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 03/11/2023] [Accepted: 04/22/2023] [Indexed: 05/16/2023]
Abstract
Neurological infections, such as Cerebral malaria (CM) and meningitis are associated with high mortality and in survivors, particularly young children, persistent neurologic deficits often remain. As brain inflammation plays a role in the development of these neurological sequelae, multiplex assays were used to assess a select set of immune mediators in both plasma and cerebrospinal fluid (CSF) from Zambian children with neurological infections. Both CM and meningitis patients showed high levels of markers for vascular inflammation, such as soluble ICAM-1 and angiopoietins. Although high levels of angiopoietin 1 and angiopoietin 2 were found in the meningitis group, their levels in the CSF were low and did not differ. As expected, there were high levels of cytokines and notably a significantly elevated IL-6 level in the CSF of the meningitis group. Interestingly, although elevated levels BDNF were found, BDNF levels were significantly higher in plasma of the meningitis group but similar in the CSF. The striking differences in plasma BDNF and IL-6 levels in the CSF point to markedly different neuro-pathological processes. Therefore, further investigations in the role of both IL-6 and BDNF in the neurological outcomes are needed.
Collapse
Affiliation(s)
- Monique F Stins
- Johns Hopkins School of Public Health, Malaria Research Institute, 615N Wolfe Street, SPH E45141, Baltimore, MD 21205, United States of America.
| | - Agnes Mtaja
- University of Zambia School of Medicine, Department of Paediatrics and Child Health, The School of Medicine, University Teaching Hospital Malaria Research Unit (SMUTH-MRU), P.O. Box 50110, Lusaka, Zambia
| | - Evan Mulendele
- University of Zambia School of Medicine, Department of Paediatrics and Child Health, The School of Medicine, University Teaching Hospital Malaria Research Unit (SMUTH-MRU), P.O. Box 50110, Lusaka, Zambia
| | - Daniel W Mwimbe
- University of Zambia School of Medicine, Department of Paediatrics and Child Health, The School of Medicine, University Teaching Hospital Malaria Research Unit (SMUTH-MRU), P.O. Box 50110, Lusaka, Zambia
| | - Gabriel Pinilla
- Johns Hopkins School of Medicine, Department of Neurology, Division of Neuroimmunology and Neuroinfectious Diseases, 600 N Wolfe Street, Baltimore, MD 21285, United States of America; Icesi University, Department of Clinical Sciences, Calle 18 No. 122-135, Cali 760031, Colombia
| | - Mable Mutengo
- University of Zambia School of Medicine, Department of Paediatrics and Child Health, The School of Medicine, University Teaching Hospital Malaria Research Unit (SMUTH-MRU), P.O. Box 50110, Lusaka, Zambia
| | - Carlos A Pardo
- Johns Hopkins School of Medicine, Department of Neurology, Division of Neuroimmunology and Neuroinfectious Diseases, 600 N Wolfe Street, Baltimore, MD 21285, United States of America
| | - James Chipeta
- University of Zambia School of Medicine, Department of Paediatrics and Child Health, The School of Medicine, University Teaching Hospital Malaria Research Unit (SMUTH-MRU), P.O. Box 50110, Lusaka, Zambia
| |
Collapse
|
2
|
Kalita E, Panda M, Rao A, Prajapati VK. Exploring the role of secretory proteins in the human infectious diseases diagnosis and therapeutics. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 133:231-269. [PMID: 36707203 DOI: 10.1016/bs.apcsb.2022.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Secretory proteins are playing important role during the host-pathogen interaction to develop the infection or protection into the cell. Pathogens developing infectious disease to human being are taken up by host macrophages or number of immune cells, play an important role in physiological, developmental and immunological function. At the same time, infectious agents are also secreting various proteins to neutralize the resistance caused by host cells and also helping the pathogens to develop the infection. Secretory proteins (secretome) are only developed at the time of host-pathogen interaction, therefore they become very important to develop the targeted and potential therapeutic strategies. Pathogen specific secretory proteins released during interaction with host cell provide opportunity to develop point of care and rapid diagnostic kits. Proteins secreted by pathogens at the time of interaction with host cell have also been found as immunogenic in nature and numbers of vaccines have been developed to control the spread of human infectious diseases. This chapter highlights the importance of secretory proteins in the development of diagnostic and therapeutic strategies to fight against human infectious diseases.
Collapse
Affiliation(s)
- Elora Kalita
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Mamta Panda
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Abhishek Rao
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Vijay Kumar Prajapati
- Department of Biochemistry, School of Life Sciences, Central University of Rajasthan, Ajmer, Rajasthan, India.
| |
Collapse
|
3
|
Nortey LN, Anning AS, Nakotey GK, Ussif AM, Opoku YK, Osei SA, Aboagye B, Ghartey-Kwansah G. Genetics of cerebral malaria: pathogenesis, biomarkers and emerging therapeutic interventions. Cell Biosci 2022; 12:91. [PMID: 35715862 PMCID: PMC9204375 DOI: 10.1186/s13578-022-00830-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 06/07/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Cerebral malaria (CM) is a preeminent cause of severe disease and premature deaths in Sub-Saharan Africa, where an estimated 90% of cases occur. The key features of CM are a deep, unarousable coma that persists for longer than 1 h in patients with peripheral Plasmodium falciparum and no other explanation for encephalopathy. Significant research efforts on CM in the last few decades have focused on unravelling the molecular underpinnings of the disease pathogenesis and the identification of potential targets for therapeutic or pharmacologic intervention. These efforts have been greatly aided by the generation and study of mouse models of CM, which have provided great insights into key events of CM pathogenesis, revealed an interesting interplay of host versus parasite factors that determine the progression of malaria to severe disease and exposed possible targets for therapeutic intervention in severe disease.
Main Body
This paper reviews our current understanding of the pathogenic and immunologic factors involved in CM. We present the current view of the roles of certain gene products e.g., the var gene, ABCA-1, ICAM-1, TNF-alpha, CD-36, PfEMP-1 and G6PD, in CM pathogenesis. We also present alterations in the blood–brain barrier as a consequence of disease proliferation as well as complicated host and parasite interactions, including the T-cell immune reaction, reduced deformation of erythrocytes and cytoadherence. We further looked at recent advances in cerebral malaria treatment interventions by emphasizing on biomarkers, new diagnostic tools and emerging therapeutic options.
Conclusion
Finally, we discuss how the current understanding of some of these pathogenic and immunologic factors could inform the development of novel therapeutic interventions to fight CM.
Collapse
|
4
|
Foko LPK, Narang G, Tamang S, Hawadak J, Jakhan J, Sharma A, Singh V. The spectrum of clinical biomarkers in severe malaria and new avenues for exploration. Virulence 2022; 13:634-653. [PMID: 36036460 PMCID: PMC9427047 DOI: 10.1080/21505594.2022.2056966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Globally, malaria is a public health concern, with severe malaria (SM) contributing a major share of the disease burden in malaria endemic countries. In this context, identification and validation of SM biomarkers are essential in clinical practice. Some biomarkers (C-reactive protein, angiopoietin 2, angiopoietin-2/1 ratio, platelet count, histidine-rich protein 2) have yielded interesting results in the prognosis of Plasmodium falciparum severe malaria, but for severe P. vivax and P. knowlesi malaria, similar evidence is missing. The validation of these biomarkers is hindered by several factors such as low sample size, paucity of evidence-evaluating studies, suboptimal values of sensitivity/specificity, poor clinical practicality of measurement methods, mixed Plasmodium infections, and good clinical value of the biomarkers for concurrent infections (pneumonia and current COVID-19 pandemic). Most of these biomarkers are non-specific to pathogens as they are related to host response and hence should be regarded as prognostic/predictive biomarkers that complement but do not replace pathogen biomarkers for clinical evaluation of SM patients. This review highlights the importance of research on diagnostic/predictive/therapeutic biomarkers, neglected malaria species, and clinical practicality of measurement methods in future studies. Finally, the importance of omics technologies for faster identification/validation of SM biomarkers is also included.
Collapse
Affiliation(s)
- Loick Pradel Kojom Foko
- Parasite and Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India
| | - Geetika Narang
- Parasite and Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India
| | - Suman Tamang
- Parasite and Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India
| | - Joseph Hawadak
- Parasite and Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India
| | - Jahnvi Jakhan
- Parasite and Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India
| | - Amit Sharma
- Parasite and Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India.,Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Vineeta Singh
- Parasite and Host Biology Group, ICMR-National Institute of Malaria Research, New Delhi, India
| |
Collapse
|
5
|
Asiedu E, Larbi A, Adankwah E, Yambah JK, Sakyi SA, Kwarteng EVS, Obiri-Yeboah D, Kwarteng A. Transcriptomic profiling identifies host-derived biomarker panels for assessing cerebral malaria. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
6
|
Lekpor CE, Botchway F, Kusi KA, Adjei AA, Wilson MD, Stiles JK, Wilson NO. Angiogenic and angiostatic factors present in the saliva of malaria patients. Malar J 2022; 21:220. [PMID: 35836234 PMCID: PMC9284857 DOI: 10.1186/s12936-022-04221-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/14/2022] [Indexed: 11/24/2022] Open
Abstract
Background Malaria related mortality is associated with significant deregulation of host inflammatory factors such as interferon-inducible protein 10, a member of the CXC or α-subfamily (CXCL10), and host angiogenic factors such as angiopoietin 1 (Ang-1) and angiopoietin 2 (Ang-2). However, detection of these factors in malaria patients requires the drawing of blood, which is invasive and increases the risk of accidental blood-borne infections. There has been an increased interest in the use of saliva as the body fluid of choice for the diagnosis of many infectious diseases including malaria. Here, saliva levels of CXCL10, Ang-1, and Ang-2 previously shown to be predictive of severe malaria in malaria patients in Ghana were assessed in malaria patients. Methods This study was conducted in the Shai-Osudoku District Hospital in Dodowa, Accra, Ghana and the study population comprised 119 malaria patients and 94 non-malaria subjects. The non-malaria subjects are healthy community participants with no malaria infection. Plasma and saliva levels of CXCL10, Ang-1 and Ang-2 of the study participants were measured using an enzyme-linked immunoassay. Complete blood counts of each participant were measured with a haematology autoanalyzer. Pearson correlation was used to evaluate the correlation between plasma and saliva levels of each biomarker in malaria patients. A p-value of < 0.05 was considered significant. Box plots of median biomarker concentrations were plotted. SPSS version 14.2 software was used for statistical analysis. Results The non-malaria subjects had a median age of 29 years compared to 23 years for malaria patients (p = 0.001). Among the malaria patients, there was a strong significant relationship between CXCL10 (R2 = 0.7, p < 0.0001) and Ang-1 (R2 = 0.7, p < 0.0001). Malaria patients had lower saliva levels of Ang-1 (p = 0.009) and higher saliva levels of CXCL10 (p = 0.004) and Ang-2 (p = 0.001) compared to non-malaria subjects. Conclusions This study provides the first evidence of elevated levels of CXCL10 and Ang-2 in the saliva of malaria patients. Detection of CXCL10, Ang-1 and Ang-2 in saliva may have a potential application for non-invasive malaria diagnosis.
Collapse
Affiliation(s)
- Cecilia Elorm Lekpor
- Department of Pathology, Korle-Bu Teaching Hospital, University of Ghana Medical School, Accra, Ghana.
| | - Felix Botchway
- Department of Chemical Pathology, University of Ghana Medical School, Korle-Bu Teaching Hospital, Accra, Ghana
| | - Kwadwo Asamoah Kusi
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana.,Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Andrew A Adjei
- Department of Pathology, Korle-Bu Teaching Hospital, University of Ghana Medical School, Accra, Ghana
| | - Michael D Wilson
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Jonathan K Stiles
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Nana O Wilson
- Department of Microbiology, Biochemistry & Immunology, Morehouse School of Medicine, Atlanta, GA, USA.
| |
Collapse
|
7
|
Harbuzariu A, Nti A, Harp KO, Cespedes JC, Driss A, Stiles JK. Neuregulin-1/ErbB4 signaling modulates Plasmodium falciparum HRP2-induced damage to brain cortical organoids. iScience 2022; 25:104407. [PMID: 35663028 PMCID: PMC9157207 DOI: 10.1016/j.isci.2022.104407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 12/21/2021] [Accepted: 05/11/2022] [Indexed: 11/30/2022] Open
Abstract
Human cerebral malaria (HCM) is a severe complication of Plasmodium falciparum (P.f.) infection that is characterized by capillary occlusions, rupture of the blood-brain barrier (BBB), perivascular cellular injury, and brain swelling. P.f.histidine-rich protein 2 (HRP2), a byproduct of parasitized red blood cell (pRBC) lysis, crosses the BBB when compromised to cause brain injury. We hypothesized that HRP2-induced neuronal damage can be attenuated by Neuregulin-1 (NRG1), an anti-inflammatory neuroprotective factor. Using brain cortical organoids, we determined that HRP2 upregulated cell death and inflammatory markers and disorganized brain organoid tissue. We identified toll-like receptors (TLR1 and 2) as potential mediators of HRP2-induced cellular damage and inflammation. Exogenous acute treatment of organoids with NRG1 attenuated HRP2 effects. The results indicate that HRP2 mediates malaria-associated HRP2-induced brain injury and inflammation and that NRG1 may be an effective therapy against HRP2 effects in the brain.
Collapse
Affiliation(s)
- Adriana Harbuzariu
- Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Annette Nti
- Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Keri Oxendine Harp
- Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Juan C. Cespedes
- Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Adel Driss
- Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | - Jonathan K. Stiles
- Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| |
Collapse
|
8
|
Idro R, Ogwang R, Barragan A, Raimondo JV, Masocha W. Neuroimmunology of Common Parasitic Infections in Africa. Front Immunol 2022; 13:791488. [PMID: 35222377 PMCID: PMC8866860 DOI: 10.3389/fimmu.2022.791488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
Parasitic infections of the central nervous system are an important cause of morbidity and mortality in Africa. The neurological, cognitive, and psychiatric sequelae of these infections result from a complex interplay between the parasites and the host inflammatory response. Here we review some of the diseases caused by selected parasitic organisms known to infect the nervous system including Plasmodium falciparum, Toxoplasma gondii, Trypanosoma brucei spp., and Taenia solium species. For each parasite, we describe the geographical distribution, prevalence, life cycle, and typical clinical symptoms of infection and pathogenesis. We pay particular attention to how the parasites infect the brain and the interaction between each organism and the host immune system. We describe how an understanding of these processes may guide optimal diagnostic and therapeutic strategies to treat these disorders. Finally, we highlight current gaps in our understanding of disease pathophysiology and call for increased interrogation of these often-neglected disorders of the nervous system.
Collapse
Affiliation(s)
- Richard Idro
- College of Health Sciences, Makerere University, Kampala, Uganda.,Centre of Tropical Neuroscience, Kitgum, Uganda.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Rodney Ogwang
- College of Health Sciences, Makerere University, Kampala, Uganda.,Centre of Tropical Neuroscience, Kitgum, Uganda.,Kenya Medical Research Institute (KEMRI) - Wellcome Trust Research Programme, Nairobi, Kenya
| | - Antonio Barragan
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Joseph Valentino Raimondo
- Division of Cell Biology, Department of Human Biology, Neuroscience Institute and Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Willias Masocha
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Safat, Kuwait
| |
Collapse
|
9
|
Jain V, Thomas T, Basak S, Sharma RK, Singh N. Sequential dysregulated plasma levels of angiopoietins (ANG-2 and ratios of ANG-2/ANG-1) are associated with malaria severity and mortality among hospital admitted cases in South Bastar Region of Chhattisgarh, Central India. Pathog Glob Health 2022; 116:47-58. [PMID: 34308785 PMCID: PMC8812749 DOI: 10.1080/20477724.2021.1953685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cerebral malaria (CM) is one of the most severe forms of P. falciparum infection, with an associated high case-fatality rate. Angiopoietins (ANG-1 and ANG-2) are important biomarkers of endothelial activation and dysfunction. This study was carried out in Maharani Hospital and associated Medical College, Jagdalpur, CG, Central India from 2010 to 2014. Based on the treatment recovery patterns, cases (n = 65) were classified as mild malaria with rapid recovery (MM-RR), n= 14; non-cerebral severe malaria with moderately fast recovery (NCSM-MFR), n= 9; CM survivors with slow recovery (CMS-SR), n= 36 and deteriorated CM non-survivors (Det-CMNS), n= 6. Plasma levels (pg/ml) of ANG-1 and ANG-2 were measured by ELISA in all the samples at the time of hospital admission and 48 hours of treatment. Levels were also measured in available samples at the third time point (time of discharge for survivors or 72 hours post-treatment in fatal cases). Data analysis was done by appropriate statistical tests using Stata 11.0 and SPSS 25.0 software. At the time of admission, ANG-2 and ratios of ANG-2/ANG-1 significantly distinguished Det-CMNS cases from MM-RR and NCSM-MFR cases with good AUC scores (0.8-0.9). Further, Det-CMNS cases could also be distinguished from MM-RR, NCSM-MFR, and CMS-SR cases by ANG-2 (AUC scores 0.9) and ratios of ANG-2/ANG-1 (AUC: 0.8-0.9) at 48 hours of treatment. Paired analysis of sequential measurement of angiopoietins revealed that compared to admission levels, the ratios of ANG-2/ANG-1 significantly declined 48 hours after treatment in MM-RR (p= 0.041), NCSM-MFR (p= 0.050), and CMS-SR (p= 0.0002) cases but not in cases of Det-CMNS (p= 0.916). In conclusion, plasma levels of ANG-2 and ratios of ANG-2/ANG-1 may serve as good biomarkers to distinguish the malaria severity at the time of hospital admission and recovery patterns upon treatment in Central India.
Collapse
Affiliation(s)
- Vidhan Jain
- Department of Virology and Zoonotic Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, MP, India
| | - Trilok Thomas
- Department of Virology and Zoonotic Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, MP, India
| | - Sanjay Basak
- Former District Malaria Officer, Maharani Hospital and Associated Medical College Jagdalpur, Chhattisgarh, India
| | - Ravendra Kumar Sharma
- Department of Statistics, ICMR-National Institute of Medical Statistics, ICMR Campus, New Delhi, India
| | - Neeru Singh
- Department of Virology and Zoonotic Diseases, ICMR-National Institute of Research in Tribal Health, Jabalpur, MP, India
| |
Collapse
|
10
|
Juliana A, Jongman R, van Meurs M, Plötz FB, Zonneveld R. Serum Levels of Markers of Endothelial Activation Are Not Associated with a Positive Blood Culture in Surinamese Children with Suspected Severe Infection. J Trop Pediatr 2021; 67:6056054. [PMID: 33381799 DOI: 10.1093/tropej/fmaa091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Systemic serum levels of markers of endothelial activation are associated with infection. We hypothesize that levels of markers of endothelial activation are associated with the presence of a positive blood culture as a manifestation of a systemic infection in children with a suspected severe infection in Suriname. METHODS In this prospective observational cohort study, children between 1 month and 18 years of age suspected of severe infection as assessed by the threating physician, and in whom laboratory testing and blood culturing was performed before start of intravenous antibiotic treatment, were recruited at the emergency department of the Academic Hospital Paramaribo, Suriname. Serum was collected at blood culturing and after 48-72 h of admission. Serum was stored for measurement of levels of Angiopoietin (Ang)-1, Ang-2, soluble (s)P-selectin, sE-selectin, vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and platelet and endothelial cell adhesion molecule-1. RESULTS Fifty-one children were included of whom 10 had a positive blood culture. Baseline characteristics were similar between children with and without a positive blood culture. No significant differences in serum levels of the Angiopoietins or soluble cellular adhesion molecules between groups were observed at start of antibiotic treatment nor after 48-72 h. CONCLUSIONS The data from this study indicate that in children with severe infection, serum levels of markers of endothelial cell activation are not associated with a positive blood culture. Thus, having a positive bacterial blood culture may not be the only factor driving endothelial activation in this patient population.
Collapse
Affiliation(s)
- Amadu Juliana
- Academic Pediatric Center Suriname, Academic Hospital Paramaribo, Paramaribo, Suriname
| | - Rianne Jongman
- Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Matijs van Meurs
- Anesthesiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.,Department of Critical Care and, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Frans B Plötz
- Department of Pediatrics, Tergooi Hospitals, Blaricum, The Netherlands.,Department of Pediatrics, Amsterdam UMC, University of Amsterdam, Emma Children's Hospital, Amsterdam, The Netherlands
| | - Rens Zonneveld
- Academic Pediatric Center Suriname, Academic Hospital Paramaribo, Paramaribo, Suriname.,Department of Pathology and Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| |
Collapse
|
11
|
Ouma BJ, Bangirana P, Ssenkusu JM, Datta D, Opoka RO, Idro R, Kain KC, John CC, Conroy AL. Plasma angiopoietin-2 is associated with age-related deficits in cognitive sub-scales in Ugandan children following severe malaria. Malar J 2021; 20:17. [PMID: 33407493 PMCID: PMC7789657 DOI: 10.1186/s12936-020-03545-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/11/2020] [Indexed: 12/27/2022] Open
Abstract
Background Elevated angiopoietin-2 (Angpt-2) concentrations are associated with worse overall neurocognitive function in severe malaria survivors, but the specific domains affected have not been elucidated. Methods Ugandan children with severe malaria underwent neurocognitive evaluation a week after hospital discharge and at 6, 12 and 24 months follow-up. The relationship between Angpt-2 concentrations and age-adjusted, cognitive sub-scale z-scores over time were evaluated using linear mixed effects models, adjusting for disease severity (coma, acute kidney injury, number of seizures in hospital) and sociodemographic factors (age, gender, height-for-age z-score, socio-economic status, enrichment in the home environment, parental education, and any preschool education of the child). The Mullen Scales of Early Learning was used in children < 5 years and the Kaufman Assessment Battery for Children 2nd edition was used in children ≥ 5 years of age. Angpt-2 levels were measured on admission plasma samples by enzyme-linked immunosorbent assay. Adjustment for multiple comparisons was conducted using the Benjamini–Hochberg Procedure of False Discovery Rate. Results Increased admission Angpt-2 concentration was associated with worse outcomes in all domains (fine and gross motor, visual reception, receptive and expressive language) in children < 5 years of age at the time of severe malaria episode, and worse simultaneous processing and learning in children < 5 years of age at the time of severe malaria who were tested when ≥ 5 years of age. No association was seen between Angpt-2 levels and cognitive outcomes in children ≥ 5 years at the time of severe malaria episode, but numbers of children and testing time points were lower for children ≥ 5 years at the time of severe malaria episode. Conclusion Elevated Angpt-2 concentration in children with severe malaria is associated with worse outcomes in multiple neurocognitive domains. The relationship between Angpt-2 and worse cognition is evident in children < 5 years of age at the time of severe malaria presentation and in selected domains in older years.
Collapse
Affiliation(s)
- Benson J Ouma
- Department of Medical Microbiology, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Paul Bangirana
- Department of Psychiatry, College of Health Sciences, Makerere University, Kampala, Uganda
| | - John M Ssenkusu
- Department of Epidemiology and Biostatistics, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Dibyadyuti Datta
- Ryan White Center for Pediatric Infectious Disease and Global Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Robert O Opoka
- Department of Paediatrics and Child Health, Makerere University College of Health Sciences, Kampala, Uganda
| | - Richard Idro
- Department of Paediatrics and Child Health, Makerere University College of Health Sciences, Kampala, Uganda.,Centre of Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Kevin C Kain
- Department of Medicine, University of Toronto and University Health Network, Toronto, Canada
| | - Chandy C John
- Ryan White Center for Pediatric Infectious Disease and Global Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrea L Conroy
- Ryan White Center for Pediatric Infectious Disease and Global Health, Indiana University School of Medicine, Indianapolis, IN, USA.
| |
Collapse
|
12
|
Omer SA, Sulaiman SM. The Placenta and Plasmodium Infections: a Case Study from Blue Nile State, Sudan. CURRENT TROPICAL MEDICINE REPORTS 2020. [DOI: 10.1007/s40475-020-00214-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
13
|
Gowda SH, Anghan H, Mishra H, Chosdol K, Bhatt M, Kumar V, Ranjan P, Aggarwal P, Wig N, Soneja M. Serum Angiopoietin-1 and -2 and VEGF are associated with severe disease in vivax malaria. J Vector Borne Dis 2020; 57:285-294. [PMID: 34856707 DOI: 10.4103/0972-9062.313969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND & OBJECTIVES Malaria continues to be a significant public health problem in tropical countries including India; however, there are limited tools to predict occurrence of severe disease due to malaria. This study was designed to evaluate the role of Angiopoietin-1 (Ang-1), Angiopoietin-2 (Ang-2), Vascular endothelial growth factor (VEGF) and Asymmetric Dimethylarginine (ADMA)as disease biomarkers in uncomplicated malaria (UM) and severe malaria (SM). METHODS This is a prospective observational study carried out at All India Institute of Medical Sciences (AIIMS), tertiary referral hospital in New Delhi, India. The study population included patients diagnosed with malaria (Plasmodium falciparum or Plasmodium vivax) either by rapid diagnostic kit test or positive peripheral smear and age more than 12 years. Forty-nine patients (25 with SM, 24 with UM) and 22 controls were recruited. In addition to routine investigations, serum concentrations of Ang-1, Ang-2, VEGF and ADMA were measured using ELISA technique. RESULTS We observed Ang-1 serum levels to be significantly lower in patients with severe malaria (7775 pg/ml) compared to uncomplicated malaria (17629 pg/ml) and healthy controls (43472 pg/ml) [p <0.001]. Ang-2 levels were significantly higher in severe malaria (11100 pg/ml) compared to uncomplicated malaria (7315 pg/ml) and healthy controls (3679 pg/ml) (p <0.001). The ratio of Ang-2/Ang-1 was significantly higher in patients with severe malaria. VEGF serum levels was significantly lower in severe malaria (130.36 pg/ml) compared to uncomplicated malaria (317.3 pg/ml). The Ang-1, Ang-2 and VEGF levels were able to differentiate severe malaria from uncomplicated malaria caused by P. vivax but not with P. falciparum. INTERPRETATION & CONCLUSION We conclude that Ang-1, Ang-2 and VEGF are markers of disease severity in vivax malaria.
Collapse
Affiliation(s)
- Srinivas H Gowda
- Department of Biochemistry, Maulana Azad Medical College, New Delhi, India
| | - Hiren Anghan
- Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
| | - Hridesh Mishra
- Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
| | - Kunzang Chosdol
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
| | - Manasvini Bhatt
- Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
| | - Vinod Kumar
- Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
| | - Piyush Ranjan
- Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
| | - Praveen Aggarwal
- Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
| | - Naveet Wig
- Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
| | - Manish Soneja
- Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
| |
Collapse
|
14
|
Nwokocha CR, Bafor EE, Ajayi OI, Ebeigbe AB. The Malaria-High Blood Pressure Hypothesis: Revisited. Am J Hypertens 2020; 33:695-702. [PMID: 32211753 DOI: 10.1093/ajh/hpaa051] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 02/24/2020] [Accepted: 03/18/2020] [Indexed: 11/14/2022] Open
Abstract
Malaria etiologies with pathophysiological similarities to hypertension currently constitute a major subject of research. The malaria-high blood pressure hypothesis is strongly supported by observations of the increasing incidence of hypertension in malaria-endemic, low- and middle-income countries with poor socioeconomic conditions, particularly in sub-Saharan African countries. Malnutrition and low birth weight with persistent symptomatic malaria presentations in pregnancy correlate strongly with the development of preeclampsia, gestational hypertension and subsequent hypertension in adult life. Evidence suggest that the link between malaria infection and high blood pressure involves interactions between malaria parasites and erythrocytes, the inflammatory process, effects of the infection during pregnancy; effects on renal and vascular functions as well as effects in sickle cell disease. Possible mechanisms which provide justification for the malaria-high blood pressure hypothesis include the following: endothelial dysfunction (reduced nitric oxide (NO) levels), impaired release of local neurotransmitters and cytokines, decrease in vascular smooth muscle cell viability and/or alterations in cellular calcium signaling leading to enhanced vascular reactivity, remodeling, and cardiomyopathies, deranged homeostasis through dehydration, elevated intracellular mediators and proinflammatory cytokine responses, possible genetic regulations, activation of the renin-angiotensin-aldosterone system mechanisms and renal derangements, severe anemia and hemolysis, renal failure, and end organ damage. Two key mediators of the malaria-high blood pressure association are: endothelial dysfunction (reduced NO) and increased angiotensin-converting enzyme activity/angiotensin II levels. Sickle cell disease is associated with protection against malaria infection and reduced blood pressure. In this review, we present the state of knowledge about the malaria-blood pressure hypothesis and suggest insights for future studies.
Collapse
Affiliation(s)
| | - Enitome E Bafor
- Department of Pharmacology and Toxicology, University of Benin, Benin City, Nigeria
| | - Olutayo I Ajayi
- Department of Physiology, College of Medical Sciences, University of Benin, Benin City, Nigeria
| | - Anthony B Ebeigbe
- Department of Physiology, College of Medical Sciences, University of Benin, Benin City, Nigeria
| |
Collapse
|
15
|
Varo R, Erice C, Johnson S, Bassat Q, Kain KC. Clinical trials to assess adjuvant therapeutics for severe malaria. Malar J 2020; 19:268. [PMID: 32709257 PMCID: PMC7382078 DOI: 10.1186/s12936-020-03340-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 07/17/2020] [Indexed: 01/07/2023] Open
Abstract
Despite potent anti-malarial treatment, mortality rates associated with severe falciparum malaria remain high. To attempt to improve outcome, several trials have assessed a variety of potential adjunctive therapeutics, however none to date has been shown to be beneficial. This may be due, at least partly, to the therapeutics chosen and clinical trial design used. Here, we highlight three themes that could facilitate the choice and evaluation of putative adjuvant interventions for severe malaria, paving the way for their assessment in randomized controlled trials. Most clinical trials of adjunctive therapeutics to date have been underpowered due to the large number of participants required to reach mortality endpoints, rendering these study designs challenging and expensive to conduct. These limitations may be mitigated by the use of risk-stratification of participants and application of surrogate endpoints. Appropriate surrogate endpoints include direct measures of pathways causally involved in the pathobiology of severe and fatal malaria, including markers of host immune and endothelial activation and microcirculatory dysfunction. We propose using circulating markers of these pathways to identify high-risk participants that would be most likely to benefit from adjunctive therapy, and further by adopting these biomarkers as surrogate endpoints; moreover, choosing interventions that target deleterious host immune responses that directly contribute to microcirculatory dysfunction, multi-organ dysfunction and death; and, finally, prioritizing where possible, drugs that act on these pathways that are already approved by the FDA, or other regulators, for other indications, and are known to be safe in target populations, including children. An emerging understanding of the critical role of the host response in severe malaria pathogenesis may facilitate both clinical trial design and the search of effective adjunctive therapeutics.
Collapse
Affiliation(s)
- Rosauro Varo
- ISGlobal, Barcelona Institute for Global Health, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
| | - Clara Erice
- Sandra-Rotman Centre for Global Health, Toronto General Research Institute, University Health Network-Toronto General Hospital, Toronto, ON, Canada
| | | | - Quique Bassat
- ISGlobal, Barcelona Institute for Global Health, Hospital Clínic, Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique.,ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain.,Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain.,Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Kevin C Kain
- Sandra-Rotman Centre for Global Health, Toronto General Research Institute, University Health Network-Toronto General Hospital, Toronto, ON, Canada. .,Department of Medicine, Division of Infectious Diseases, Tropical Disease Unit, University of Toronto, Toronto, Canada.
| |
Collapse
|
16
|
Evaluation of Angiopoietins 1 and 2 in Malaria-Infested Children. JOURNAL OF ENVIRONMENTAL AND PUBLIC HEALTH 2020; 2020:2169763. [PMID: 32565839 PMCID: PMC7271246 DOI: 10.1155/2020/2169763] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 01/09/2020] [Indexed: 11/17/2022]
Abstract
Background Malaria could affect people of all ages, most especially young children. The study evaluated the levels of serum angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) which are critical regulators of endothelial activation and integrity with some hematological parameters (total white blood cell counts (WBC), total red blood cell counts (RBC), platelet counts, and malaria parasite density) in malaria-infected children. Method A total of 92 blood samples from children between the ages of 6 months to 15 years were analyzed. The samples consisted of 30 cases of severe malaria, 40 cases of uncomplicated malaria, and 22 apparently healthy subjects served as control. Serum Ang-1 and -2 levels were determined using the enzyme-linked immunosorbent assay technique. The hematological parameters were determined using the WHO standard. Results There was significant decrease (p < 0.05) in serum Ang-1 of uncomplicated malaria and severe malaria compared with the control, while significant increase (p < 0.05) was observed in Ang-2 and Ang-2/Ang-1 ratio in uncomplicated malaria and severe malaria compared with the control. RBC and platelet showed significant decrease, while WBC showed significant increase in severe malaria compared with uncomplicated malaria and control. Conclusion This study showed that subjects with malaria infection had a significant increase of Ang-2 and Ang-2 : Ang-1 ratio but presented with a significant decrease of Ang-1. Ang-1 and Ang-2 may be used to determine the severity of malaria infection since their levels differ significantly in malaria subjects compared with the control.
Collapse
|
17
|
Association of Angiopoietin Dysregulation in Placental Malaria with Adverse Birth Outcomes. DISEASE MARKERS 2020; 2020:6163487. [PMID: 32399088 PMCID: PMC7201683 DOI: 10.1155/2020/6163487] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 12/02/2019] [Accepted: 12/23/2019] [Indexed: 11/23/2022]
Abstract
Malaria in pregnancy causes adverse birth outcomes due to sequestration of Plasmodium falciparum-infected erythrocytes in the placenta. Angiopoietins are critical regulators of vascular development and formation of placental villous vasculature. Angiopoietin-1 and Angiopoietin-2 concentrations were measured in peripheral and placental plasma samples from 70 malaria-infected and 216 control women using commercially available DuoSet ELISA development kit. Angiopoietins increased in placental plasma (ANG1-5833.5 pg/ml and ANG2-9580.6 pg/ml) as compared to peripheral plasma (ANG1-2293.1 pg/ml and ANG2-1198.9 pg/ml, p < 0.0001). The concentration of placental and peripheral ANG1 (6099.23 pg/ml and 2320.5 pg/ml) was significantly lower (5013.5 pg/ml, 2208.5 pg/ml), and ANG2 (9553.3 pg/ml, 1180.92 pg/ml) was significantly higher (9664.6 pg/ml, 1254.4 pg/ml) in malaria-positive cases as compared to malaria-negative (p < 0.0001). The association of dysregulated angiopoietins in malaria with adverse birth outcomes showed that the peripheral and placental ANG1 concentration was lower and ANG2 concentration was higher in low-birth-weight baby and stillbirth birth outcome as compared to normal deliveries among malaria-positive group. Therefore, ANG1 and ANG2 could be considered a biomarker for adverse outcome during malaria in pregnancy.
Collapse
|
18
|
Balanza N, Erice C, Ngai M, Varo R, Kain KC, Bassat Q. Host-Based Prognostic Biomarkers to Improve Risk Stratification and Outcome of Febrile Children in Low- and Middle-Income Countries. Front Pediatr 2020; 8:552083. [PMID: 33072673 PMCID: PMC7530621 DOI: 10.3389/fped.2020.552083] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/12/2020] [Indexed: 12/15/2022] Open
Abstract
Fever is one of the leading causes for pediatric medical consultation and the most common symptom at clinical presentation in low- and middle-income countries (LMICs). Most febrile episodes are due to self-limited infections, but a small proportion of children will develop life-threatening infections. The early recognition of children who have or are progressing to a critical illness among all febrile cases is challenging, and there are currently no objective and quantitative tools to do so. This results in increased morbidity and mortality among children with impending life-threatening infections, whilst contributing to the unnecessary prescription of antibiotics, overwhelming health care facilities, and harm to patients receiving avoidable antimicrobial treatment. Specific fever origin is difficult to ascertain and co-infections in LMICs are common. However, many severe infections share common pathways of host injury irrespective of etiology, including immune and endothelial activation that contribute to the pathobiology of sepsis (i.e., pathogen "agnostic" mechanisms of disease). Importantly, mediators of these pathways are independent markers of disease severity and outcome. We propose that measuring circulating levels of these factors can provide quantitative and objective evidence to: enable early recognition of severe infection; guide patient triage and management; enhance post-discharge risk stratification and follow up; and mitigate potential gender bias in clinical decisions. Here, we review the clinical and biological evidence supporting the clinical utility of host immune and endothelial activation biomarkers as components of novel rapid triage tests, and discuss the challenges and needs for developing and implementing such tools.
Collapse
Affiliation(s)
- Núria Balanza
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Clara Erice
- Sandra-Rotman Centre for Global Health, Toronto General Research Institute, University Health Network-Toronto General Hospital, Toronto, ON, Canada.,Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Michelle Ngai
- Sandra-Rotman Centre for Global Health, Toronto General Research Institute, University Health Network-Toronto General Hospital, Toronto, ON, Canada.,Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Rosauro Varo
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
| | - Kevin C Kain
- Sandra-Rotman Centre for Global Health, Toronto General Research Institute, University Health Network-Toronto General Hospital, Toronto, ON, Canada.,Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Quique Bassat
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique.,ICREA, Barcelona, Spain.,Pediatric Infectious Diseases Unit, Pediatrics Department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain.,Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| |
Collapse
|
19
|
Brief Report: Higher Levels of Angiopoietin-1 Are Associated With Early and Sustained Viral Suppression in Children Living With Vertically Acquired HIV. J Acquir Immune Defic Syndr 2019; 80:590-595. [PMID: 30865052 DOI: 10.1097/qai.0000000000001955] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Systemic inflammation, platelet dysfunction, and endothelial activation persist in people living with HIV despite sustained virologic suppression (SVS) with combined antiretroviral therapy (cART) and may lead to complications such as atherosclerosis and cardiovascular disease. Angiopoietin-1 (Ang-1) is a key regulator of angiogenesis and endothelial activation and has been studied as an objective biomarker in disease states such as atherosclerosis, sepsis, and severe malaria. SETTING Eight pediatric HIV care centers across Canada. METHODS Cross-sectional study of 61 children living with vertically acquired HIV on cART with undetectable RNA viral load. Plasma levels of Ang-1 were measured by ELISA and analyzed in relation to clinical characteristics abstracted from medical records. RESULTS Ang-1 levels were directly correlated with clinical indices of virologic control: cumulative proportion of life on effective cART (ρ = +0.35, P = 0.0078) and cumulative proportion of life with SVS (ρ = +0.36, P = 0.0049). Furthermore, higher Ang-1 levels were associated with younger age at SVS (ρ = -0.56, P < 0.0001). These associations remained statistically significant in multivariable linear regression models adjusting for potential confounders (P < 0.05 for all associations). CONCLUSIONS Early effective cART and SVS were associated with higher Ang-1 levels in children living with vertically acquired HIV-1.
Collapse
|
20
|
Pham TT, Punsawad C, Glaharn S, De Meyer SF, Viriyavejakul P, Van den Steen PE. Release of endothelial activation markers in lungs of patients with malaria-associated acute respiratory distress syndrome. Malar J 2019; 18:395. [PMID: 31796023 PMCID: PMC6891978 DOI: 10.1186/s12936-019-3040-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 11/26/2019] [Indexed: 11/17/2022] Open
Abstract
Background Malaria-associated acute respiratory distress syndrome (MA-ARDS) is an understudied complication of malaria and is characterized by pulmonary inflammation and disruption of the alveolar-capillary membrane. Its pathogenesis remains poorly understood. Since endothelial activation plays an important role in other malarial complications, the expression of two endothelial activation markers, von Willebrand factor (VWF) and angiopoietin-2 (ANG-2), was investigated in the lungs of patients with MA-ARDS. Methods Post-mortem lung sections of Plasmodium falciparum-infected patients without alveolar oedema (NA), P. falciparum-infected patients with alveolar oedema (MA-ARDS), and uninfected people who died accidentally with no pathological changes to the lungs (CON) were immunohistochemically stained for VWF and ANG-2, and were evaluated with semi-quantitative analysis. Results Alveolar oedematous VWF and ANG-2 and intravascular VWF staining were significantly increased in patients with MA-ARDS versus infected and uninfected control groups. The levels of VWF in the alveolar septa and endothelial lining of large blood vessels of patients with MA-ARDS was significantly decreased compared to controls. ANG-2 expression was increased in the alveolar septa of malaria patients without alveolar oedema versus control patients, while ANG-2+ leukocytes were increased in the alveoli in both infected patient groups. Conclusions This study documents a high level of VWF and ANG-2, two endothelial activation markers in the oedematous alveoli of post-mortem lung sections of Thai patients with MA-ARDS. Decreased detection of VWF in the endothelial lining of blood vessels, in parallel with an increased presence of intravascular VWF staining suggests marked endothelial activation and Weibel–Palade body release in the lungs of patients with MA-ARDS.
Collapse
Affiliation(s)
- Thao-Thy Pham
- Laboratory of Immunoparasitology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, University of Leuven, Leuven, Belgium
| | - Chuchard Punsawad
- School of Medicine, Walailak University, Nakhon Si Thammarat, Thailand
| | - Supattra Glaharn
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Simon F De Meyer
- Laboratory for Thrombosis Research, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Parnpen Viriyavejakul
- Department of Tropical Pathology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Philippe E Van den Steen
- Laboratory of Immunoparasitology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, University of Leuven, Leuven, Belgium.
| |
Collapse
|
21
|
Erice C, Kain KC. New insights into microvascular injury to inform enhanced diagnostics and therapeutics for severe malaria. Virulence 2019; 10:1034-1046. [PMID: 31775570 PMCID: PMC6930010 DOI: 10.1080/21505594.2019.1696621] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/05/2019] [Accepted: 11/13/2019] [Indexed: 12/25/2022] Open
Abstract
Severe malaria (SM) has high mortality and morbidity rates despite treatment with potent antimalarials. Disease onset and outcome is dependent upon both parasite and host factors. Infected erythrocytes bind to host endothelium contributing to microvascular occlusion and dysregulated inflammatory and immune host responses, resulting in endothelial activation and microvascular damage. This review focuses on the mechanisms of host endothelial and microvascular injury. Only a small percentage of malaria infections (≤1%) progress to SM. Early recognition and treatment of SM can improve outcome, but we lack triage tools to identify SM early in the course of infection. Current point-of-care pathogen-based rapid diagnostic tests do not address this critical barrier. Immune and endothelial activation have been implicated in the pathobiology of SM. We hypothesize that measuring circulating mediators of these pathways at first clinical presentation will enable early triage and treatment of SM. Moreover, that host-based interventions that modulate these pathways will stabilize the microvasculature and improve clinical outcome over that of antimalarial therapy alone.
Collapse
Affiliation(s)
- Clara Erice
- Sandra-Rotman Centre for Global Health, Toronto General Research Institute, University Health Network-Toronto General Hospital, Toronto, Ontario, Canada
| | - Kevin C Kain
- Sandra-Rotman Centre for Global Health, Toronto General Research Institute, University Health Network-Toronto General Hospital, Toronto, Ontario, Canada
- Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, Canada
| |
Collapse
|
22
|
Leligdowicz A, Richard-Greenblatt M, Wright J, Crowley VM, Kain KC. Endothelial Activation: The Ang/Tie Axis in Sepsis. Front Immunol 2018; 9:838. [PMID: 29740443 PMCID: PMC5928262 DOI: 10.3389/fimmu.2018.00838] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 04/05/2018] [Indexed: 12/21/2022] Open
Abstract
Sepsis, a dysregulated host response to infection that causes life-threatening organ dysfunction, is a highly heterogeneous syndrome with no specific treatment. Although sepsis can be caused by a wide variety of pathogenic organisms, endothelial dysfunction leading to vascular leak is a common mechanism of injury that contributes to the morbidity and mortality associated with the syndrome. Perturbations to the angiopoietin (Ang)/Tie2 axis cause endothelial cell activation and contribute to the pathogenesis of sepsis. In this review, we summarize how the Ang/Tie2 pathway is implicated in sepsis and describe its prognostic as well as therapeutic utility in life-threatening infections.
Collapse
Affiliation(s)
- Aleksandra Leligdowicz
- Sandra Rotman Centre for Global Health, University Health Network and University of Toronto, Toronto, ON, Canada
| | - Melissa Richard-Greenblatt
- Sandra Rotman Centre for Global Health, University Health Network and University of Toronto, Toronto, ON, Canada
| | - Julie Wright
- Sandra Rotman Centre for Global Health, University Health Network and University of Toronto, Toronto, ON, Canada
| | - Valerie M Crowley
- Sandra Rotman Centre for Global Health, University Health Network and University of Toronto, Toronto, ON, Canada
| | - Kevin C Kain
- Sandra Rotman Centre for Global Health, University Health Network and University of Toronto, Toronto, ON, Canada
| |
Collapse
|
23
|
Crowley VM, Ayi K, Lu Z, Liby KT, Sporn M, Kain KC. Synthetic oleanane triterpenoids enhance blood brain barrier integrity and improve survival in experimental cerebral malaria. Malar J 2017; 16:463. [PMID: 29137631 PMCID: PMC5686938 DOI: 10.1186/s12936-017-2109-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 11/04/2017] [Indexed: 12/31/2022] Open
Abstract
Background Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection associated with high mortality and neurocognitive impairment in survivors. New anti-malarials and host-based adjunctive therapy may improve clinical outcome in CM. Synthetic oleanane triterpenoid (SO) compounds have shown efficacy in the treatment of diseases where inflammation and oxidative stress contribute to pathogenesis. Methods A derivative of the SO 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO), CDDO-ethyl amide (CDDO-EA) was investigated for the treatment of severe malaria in a pre-clinical model. CDDO-EA was evaluated in vivo as a monotherapy as well as adjunctive therapy with parenteral artesunate in the Plasmodium berghei strain ANKA experimental cerebral malaria (ECM) model. Results CDDO-EA alone improved outcome in ECM and, given as adjunctive therapy in combination with artesunate, it significantly improved outcome over artesunate alone (p = 0.009). Improved survival was associated with reduced inflammation, enhanced endothelial stability and blood–brain barrier integrity. Survival was improved even when administered late in the disease course after the onset of neurological symptoms. Conclusions These results indicate that SO are a new class of immunomodulatory drugs and support further studies investigating this class of agents as potential adjunctive therapy for severe malaria.
Collapse
Affiliation(s)
- Valerie M Crowley
- S. A. Rotman Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
| | - Kodjo Ayi
- S. A. Rotman Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
| | - Ziyue Lu
- S. A. Rotman Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada
| | - Karen T Liby
- Department of Pharmacology, Dartmouth Medical School, Hanover, NH, USA
| | - Michael Sporn
- Department of Pharmacology, Dartmouth Medical School, Hanover, NH, USA
| | - Kevin C Kain
- S. A. Rotman Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, Canada. .,Department of Medicine, University of Toronto, Toronto, ON, Canada. .,Tropical Diseases Unit, Division of Infectious Diseases, Department of Medicine, UHN-Toronto General Hospital, Toronto, ON, Canada.
| |
Collapse
|
24
|
Saharinen P, Eklund L, Alitalo K. Therapeutic targeting of the angiopoietin-TIE pathway. Nat Rev Drug Discov 2017; 16:635-661. [PMID: 28529319 DOI: 10.1038/nrd.2016.278] [Citation(s) in RCA: 325] [Impact Index Per Article: 46.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The endothelial angiopoietin (ANG)-TIE growth factor receptor pathway regulates vascular permeability and pathological vascular remodelling during inflammation, tumour angiogenesis and metastasis. Drugs that target the ANG-TIE pathway are in clinical development for oncological and ophthalmological applications. The aim is to complement current vascular endothelial growth factor (VEGF)-based anti-angiogenic therapies in cancer, wet age-related macular degeneration and macular oedema. The unique function of the ANG-TIE pathway in vascular stabilization also renders this pathway an attractive target in sepsis, organ transplantation, atherosclerosis and vascular complications of diabetes. This Review covers key aspects of the function of the ANG-TIE pathway in vascular disease and describes the recent development of novel therapeutics that target this pathway.
Collapse
Affiliation(s)
- Pipsa Saharinen
- Wihuri Research Institute and Translational Cancer Biology Program, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, FI-00014 Helsinki, Finland
| | - Lauri Eklund
- Oulu Center for Cell-Matrix Research, Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, Aapistie 5A, University of Oulu, 90220 Oulu, Finland
| | - Kari Alitalo
- Wihuri Research Institute and Translational Cancer Biology Program, Biomedicum Helsinki, University of Helsinki, Haartmaninkatu 8, P.O. Box 63, FI-00014 Helsinki, Finland
| |
Collapse
|
25
|
de Jong GM, Slager JJ, Verbon A, van Hellemond JJ, van Genderen PJJ. Systematic review of the role of angiopoietin-1 and angiopoietin-2 in Plasmodium species infections: biomarkers or therapeutic targets? Malar J 2016; 15:581. [PMID: 27905921 PMCID: PMC5134107 DOI: 10.1186/s12936-016-1624-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 11/19/2016] [Indexed: 03/01/2023] Open
Abstract
BACKGROUND Levels of both angiopoietin-1 (Ang-1) and angiopoietin-2 (Ang-2) correlate with malaria disease severity and are proposed as biomarkers and possible therapeutic targets. To establish their role in malaria, a systematic review was performed of the literature on Ang-1 and Ang-2 with regard to their potential as biomarkers in malaria and discuss their possible place in adjuvant treatment regimens. METHODS Ten electronic databases were systematically searched to identify studies investigating Ang-1 and Ang-2 in human and murine malaria in both clinical and experimental settings. Information about the predictive value of Ang-1 and Ang-2 for disease severity and their regulatory changes in interventional studies were extracted. RESULTS Some 579 studies were screened; 26 were included for analysis. In all five studies that determined Ang-1 levels and in all 11 studies that determined Ang-2 in different disease severity states in falciparum malaria, a decline in Ang-1 and an increase of Ang-2 levels was associated with increasing disease severity. All nine studies that determined angiopoietin levels in Plasmodium falciparum patients to study their ability as biomarkers could distinguish between multiple disease severity states; the more the disease severity states differed, the better they could be distinguished. Five studies differentiating malaria survivors from non-survivors with Ang-2 as marker found an AUROC in a range of 0.71-0.83, which performed as well or better than lactate. Prophylactic administration of FTY720, rosiglitazone or inhalation of nitric oxide (NO) during malaria disease in mice resulted in an increase in Ang-1, a decrease in Ang-2 and an increased survival. For rosiglitazone, a decrease in Ang-2/Ang-1 ratio was observed after post-infection treatment in mice and humans with malaria, but for inhalation of NO, an effect on Ang-1 and survival was only observed in mice. CONCLUSION Both Ang-1 and Ang-2 levels correlate with and can distinguish between malaria disease severity states within the group of malaria-infected patients. However, distinct comparisons of disease severity states were made in distinct studies and not all distinctions made had clinical relevance. Changes in levels of Ang-1 and Ang-2 might also reflect treatment effectiveness and are promising therapeutic targets as part of multi-targeted therapy.
Collapse
Affiliation(s)
- Gerdie M. de Jong
- Institute for Tropical Diseases, Harbour Hospital, Haringvliet 2, Rotterdam, The Netherlands
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - Jasper J. Slager
- Institute for Tropical Diseases, Harbour Hospital, Haringvliet 2, Rotterdam, The Netherlands
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - Annelies Verbon
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | - Jaap J. van Hellemond
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC, Rotterdam, The Netherlands
| | | |
Collapse
|
26
|
Vásquez AM, Blair S, García LF, Segura C. Plasmodium falciparum isolates from patients with uncomplicated malaria promote endothelial inflammation. Microbes Infect 2016; 19:132-141. [PMID: 27717894 DOI: 10.1016/j.micinf.2016.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 09/21/2016] [Accepted: 09/27/2016] [Indexed: 12/23/2022]
Abstract
The ability of Plasmodium falciparum infected erythrocytes (Pf-IEs) to activate endothelial cells has been described; however, the interaction of the endothelium with Pf-IEs field isolates from patients has been less characterized. Previous reports have shown that isolates alter the endothelial permeability and apoptosis. In this study, the adhesion of 19 uncomplicated malaria isolates to Human Dermal Microvascular Endothelial Cells (HDMEC), and their effect on the expression of ICAM-1 and proinflammatory molecules (sICAM-1, IL-6, IL-8, and MCP-1) was evaluated. P. falciparum isolates adhered to resting and TNFα-activated HDEMC cells at different levels. All isolates increased the ICAM-1 expression on the membrane (mICAM-1) of HDMEC and increased the release of its soluble form (sICAM-1), as well the production of IL-6, IL-8 and MCP-1 by HDMEC with no signs of cell apoptosis. No correlation between parasite adhesion and production of cytokines was observed. In conclusion, isolates from uncomplicated malaria can induce a proinflammatory response in endothelial cells that may play a role during the initial inflammatory response to parasite infection; however, a continuous activation of the endothelium can contribute to pathogenesis.
Collapse
Affiliation(s)
- Ana María Vásquez
- Grupo Malaria, Universidad de Antioquia, Carrera 53 No. 61 - 30, Lab 610, Medellín, Colombia.
| | - Silvia Blair
- Grupo Malaria, Universidad de Antioquia, Carrera 53 No. 61 - 30, Lab 610, Medellín, Colombia
| | - Luis F García
- Grupo de Inmunología Celular e Inmunogenética (GICIG), Sede de Investigación Universitaria, Universidad de Antioquia, Carrera 53 No. 61 - 30, Lab 410, Medellín, Colombia
| | - Cesar Segura
- Grupo Malaria, Universidad de Antioquia, Carrera 53 No. 61 - 30, Lab 610, Medellín, Colombia
| |
Collapse
|
27
|
Conroy AL, Hawkes M, McDonald CR, Kim H, Higgins SJ, Barker KR, Namasopo S, Opoka RO, John CC, Liles WC, Kain KC. Host Biomarkers Are Associated With Response to Therapy and Long-Term Mortality in Pediatric Severe Malaria. Open Forum Infect Dis 2016; 3:ofw134. [PMID: 27703996 PMCID: PMC5047396 DOI: 10.1093/ofid/ofw134] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 06/16/2016] [Indexed: 11/13/2022] Open
Abstract
Background. Host responses to infection are critical determinants of disease severity and clinical outcome. The development of tools to risk stratify children with malaria is needed to identify children most likely to benefit from targeted interventions. Methods. This study investigated the kinetics of candidate biomarkers of mortality associated with endothelial activation and dysfunction (angiopoietin-2 [Ang-2], soluble FMS-like tyrosine kinase-1 [sFlt-1], and soluble intercellular adhesion molecule-1 [sICAM-1]) and inflammation (10 kDa interferon γ-induced protein [CXCL10/IP-10] and soluble triggering receptor expressed on myeloid cells-1 [sTREM-1]) in the context of a randomized, double-blind, placebo-controlled, parallel-arm trial evaluating inhaled nitric oxide versus placebo as adjunctive therapy to parenteral artesunate for severe malaria. One hundred eighty children aged 1-10 years were enrolled at Jinja Regional Referral Hospital in Uganda and followed for up to 6 months. Results. There were no differences between the 2 study arms in the rate of biomarker recovery. Median levels of Ang-2, CXCL10, and sFlt-1 were higher at admission in children who died in-hospital (n = 15 of 180; P < .001, P = .027, and P = .004, respectively). Elevated levels of Ang-2, sTREM-1, CXCL10, and sICAM-1 were associated with prolonged clinical recovery times in survivors. The Ang-2 levels were also associated with postdischarge mortality (P < .0001). No biomarkers were associated with neurodisability. Conclusions. Persistent endothelial activation and dysfunction predict survival in children admitted with severe malaria.
Collapse
Affiliation(s)
- Andrea L Conroy
- Sandra A. Rotman Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, University of Toronto, Canada; Department of Pediatrics, Indiana University School of Medicine, Indianapolis
| | - Michael Hawkes
- Sandra A. Rotman Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, University of Toronto, Canada; Division of Pediatric Infectious Diseases, University of Alberta, Edmonton, Canada
| | - Chloe R McDonald
- Sandra A. Rotman Laboratories, Sandra Rotman Centre for Global Health , University Health Network-Toronto General Hospital, University of Toronto , Canada
| | - Hani Kim
- Sandra A. Rotman Laboratories, Sandra Rotman Centre for Global Health , University Health Network-Toronto General Hospital, University of Toronto , Canada
| | - Sarah J Higgins
- Sandra A. Rotman Laboratories, Sandra Rotman Centre for Global Health , University Health Network-Toronto General Hospital, University of Toronto , Canada
| | - Kevin R Barker
- Sandra A. Rotman Laboratories, Sandra Rotman Centre for Global Health , University Health Network-Toronto General Hospital, University of Toronto , Canada
| | | | - Robert O Opoka
- Department of Paediatrics and Child Health , Mulago Hospital and Makerere University , Kampala , Uganda
| | - Chandy C John
- Department of Pediatrics , Indiana University School of Medicine , Indianapolis
| | - W Conrad Liles
- Department of Medicine , University of Washington , Seattle
| | - Kevin C Kain
- Sandra A. Rotman Laboratories, Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, University of Toronto, Canada; Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, University of Toronto, Canada
| |
Collapse
|
28
|
Abstract
Rationale: Several studies have demonstrated links between infectious diseases and cardiovascular conditions. Malaria and hypertension are widespread in many low- and middle-income countries, but the possible link between them has not been considered. Objective: In this article, we outline the basis for a possible link between malaria and hypertension and discuss how the hypothesis could be confirmed or refuted. Methods and Results: We reviewed published literature on factors associated with hypertension and checked whether any of these were also associated with malaria. We then considered various study designs that could be used to test the hypothesis. Malaria causes low birth weight, malnutrition, and inflammation, all of which are associated with hypertension in high-income countries. The hypothetical link between malaria and hypertension can be tested through the use of ecological, cohort, or Mendelian randomization studies, each of which poses specific challenges. Conclusions: Confirmation of the existence of a causative link with malaria would be a paradigm shift in efforts to prevent and control hypertension and would stimulate wider research on the links between infectious and noncommunicable disease.
Collapse
Affiliation(s)
- Anthony O Etyang
- From the Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Program, Kilifi, Kenya (A.O.E., J.A.G.S.); Department of Infectious Disease Epidemiology (A.O.E., J.A.G.S.), and Department of Non-Communicable Disease Epidemiology (L.S.), London School of Hygiene and Tropical Medicine, London, United Kingdom; and Cardiovascular Medicine Group, Division of Diabetes and Nutritional Sciences, King's College, London, United Kingdom (J.K.C.).
| | - Liam Smeeth
- From the Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Program, Kilifi, Kenya (A.O.E., J.A.G.S.); Department of Infectious Disease Epidemiology (A.O.E., J.A.G.S.), and Department of Non-Communicable Disease Epidemiology (L.S.), London School of Hygiene and Tropical Medicine, London, United Kingdom; and Cardiovascular Medicine Group, Division of Diabetes and Nutritional Sciences, King's College, London, United Kingdom (J.K.C.)
| | - J Kennedy Cruickshank
- From the Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Program, Kilifi, Kenya (A.O.E., J.A.G.S.); Department of Infectious Disease Epidemiology (A.O.E., J.A.G.S.), and Department of Non-Communicable Disease Epidemiology (L.S.), London School of Hygiene and Tropical Medicine, London, United Kingdom; and Cardiovascular Medicine Group, Division of Diabetes and Nutritional Sciences, King's College, London, United Kingdom (J.K.C.)
| | - J Anthony G Scott
- From the Department of Epidemiology and Demography, KEMRI-Wellcome Trust Research Program, Kilifi, Kenya (A.O.E., J.A.G.S.); Department of Infectious Disease Epidemiology (A.O.E., J.A.G.S.), and Department of Non-Communicable Disease Epidemiology (L.S.), London School of Hygiene and Tropical Medicine, London, United Kingdom; and Cardiovascular Medicine Group, Division of Diabetes and Nutritional Sciences, King's College, London, United Kingdom (J.K.C.)
| |
Collapse
|
29
|
Ghosh S, Sengupta A, Sharma S, Sonawat HM. Early prediction of cerebral malaria by (1)H NMR based metabolomics. Malar J 2016; 15:198. [PMID: 27066781 PMCID: PMC4828763 DOI: 10.1186/s12936-016-1256-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 03/31/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cerebral malaria (CM) is a life-threatening disease, caused mainly by Plasmodium falciparum in humans. In adults only 1-2% of P. falciparum-infected hosts transit to the cerebral form of the disease while most exhibit non-cerebral malaria (NCM). The perturbed metabolic pathways of CM and NCM have been reported. Early marker(s) of CM is(are) not known and by the time a patient exhibits the pathological symptoms of CM, the disease has progressed. Murine CM, like the human disease, is difficult to assign to specific animals at early stage and hence the challenge to treat CM at pre-clinical stage of the disease. This is the first report of prediction of CM in mice using a novel strategy based on (1)H nuclear magnetic resonance (NMR)-based metabolomics. METHODS Mice were infected with malarial parasites, and serum was collected from all the animals (CM/NCM) before CM symptoms were apparent. The assignment of mice as NCM/CM at an early time point is based on their symptoms at days 8-9 post-infection (pi). The serum samples were subjected to (1)H NMR-based metabolomics. (1)H NMR spectra of the serum samples, collected at various time points (pi) in multiple sets of experiments, were subjected to multivariate analyses. RESULTS The results from orthogonal partial least square discriminant analyses (OPLS-DA) suggest that the animals with CM start to diverge out in metabolic profile and were distinct on day 4 pi, although by physical observation they were indistinguishable from the NCM. The metabolites that appeared to contribute to this distinction were serum lipids and lipoproteins, and 14-19% enhancement was observed in mice afflicted with CM. A cut-off of 14% change of total lipoproteins in serum predicts 54-71% CM in different experiments at day 4 pi. CONCLUSION This study clearly demonstrates the possibility of differentiating and identifying animals with CM at an early, pre-clinical stage. The strategy, based on metabolite profile of serum, tested with different batches of animals in both the sex and across different times of the year, is found to be robust. This is the first such study of pre-clinical prognosis of CM.
Collapse
Affiliation(s)
- Soumita Ghosh
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1-Homi Bhabha Road, Mumbai, 400 005, India
| | - Arjun Sengupta
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1-Homi Bhabha Road, Mumbai, 400 005, India
| | - Shobhona Sharma
- Department of Biological Sciences, Tata Institute of Fundamental Research, 1-Homi Bhabha Road, Mumbai, 400 005, India.
| | - Haripalsingh M Sonawat
- Department of Chemical Sciences, Tata Institute of Fundamental Research, 1-Homi Bhabha Road, Mumbai, 400 005, India.
| |
Collapse
|
30
|
Elphinstone RE, Riley F, Lin T, Higgins S, Dhabangi A, Musoke C, Cserti-Gazdewich C, Regan RF, Warren HS, Kain KC. Dysregulation of the haem-haemopexin axis is associated with severe malaria in a case-control study of Ugandan children. Malar J 2015; 14:511. [PMID: 26691827 PMCID: PMC4687388 DOI: 10.1186/s12936-015-1028-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/02/2015] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Malaria is associated with haemolysis and the release of plasma haem. Plasma haem can cause endothelial injury and organ dysfunction, and is normally scavenged by haemopexin to limit toxicity. It was hypothesized that dysregulation of the haem-haemopexin pathway contributes to severe and fatal malaria infections. METHODS Plasma levels of haemin (oxidized haem), haemopexin, haptoglobin, and haemoglobin were quantified in a case-control study of Ugandan children with Plasmodium falciparum malaria. Levels at presentation were compared in children with uncomplicated malaria (UM; n = 29), severe malarial anaemia (SMA; n = 27) or cerebral malaria (CM; n = 31), and evaluated for utility in predicting fatal (n = 19) vs non-fatal (n = 39) outcomes in severe disease. A causal role for haemopexin was assessed in a pre-clinical model of experimental cerebral malaria (ECM), following disruption of mouse haemopexin gene (hpx). Analysis was done using Kruskall Wallis tests, Mann-Whitney tests, log-rank tests for survival, and repeated measures ANOVA. RESULTS In Ugandan children presenting with P. falciparum malaria, haemin levels were higher and haemopexin levels were lower in SMA and CM compared to children with UM (haemin, p < 0.01; haemopexin, p < 0.0001). Among all cases of severe malaria, elevated levels of haemin and cell-free haemoglobin at presentation were associated with subsequent mortality (p < 0.05). Compared to ECM-resistant BALB/c mice, susceptible C57BL/6 mice had lower circulating levels of haemopexin (p < 0.01), and targeted deletion of the haemopexin gene, hpx, resulted in increased mortality compared to their wild type littermates (p < 0.05). CONCLUSIONS These data indicate that plasma levels of haemin and haemopexin measured at presentation correlate with malaria severity and levels of haemin and cell-free haemoglobin predict outcome in paediatric severe malaria. Mechanistic studies in the ECM model support a causal role for the haem-haemopexin axis in ECM pathobiology.
Collapse
Affiliation(s)
- Robyn E Elphinstone
- Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, ON, Canada. .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada. .,Tropical Disease Unit, Department of Medicine, University of Toronto, Toronto, ON, Canada.
| | - Frank Riley
- Infectious Disease Unit, Department of Pediatrics, Massachusetts General Hospital, Boston, MA, USA.
| | - Tian Lin
- Infectious Disease Unit, Department of Pediatrics, Massachusetts General Hospital, Boston, MA, USA.
| | - Sarah Higgins
- Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, ON, Canada. .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada. .,Tropical Disease Unit, Department of Medicine, University of Toronto, Toronto, ON, Canada.
| | - Aggrey Dhabangi
- Makerere University College of Health Sciences, Kampala, Uganda.
| | - Charles Musoke
- Makerere University College of Health Sciences, Kampala, Uganda.
| | - Christine Cserti-Gazdewich
- Laboratory Medicine Program (Transfusion Medicine), University Health Network/University of Toronto, Toronto, ON, Canada.
| | - Raymond F Regan
- Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, PA, USA.
| | - H Shaw Warren
- Infectious Disease Unit, Department of Pediatrics, Massachusetts General Hospital, Boston, MA, USA.
| | - Kevin C Kain
- Sandra Rotman Centre for Global Health, University Health Network-Toronto General Hospital, Toronto, ON, Canada. .,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada. .,Tropical Disease Unit, Department of Medicine, University of Toronto, Toronto, ON, Canada.
| |
Collapse
|
31
|
Deroost K, Pham TT, Opdenakker G, Van den Steen PE. The immunological balance between host and parasite in malaria. FEMS Microbiol Rev 2015; 40:208-57. [PMID: 26657789 DOI: 10.1093/femsre/fuv046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
Coevolution of humans and malaria parasites has generated an intricate balance between the immune system of the host and virulence factors of the parasite, equilibrating maximal parasite transmission with limited host damage. Focusing on the blood stage of the disease, we discuss how the balance between anti-parasite immunity versus immunomodulatory and evasion mechanisms of the parasite may result in parasite clearance or chronic infection without major symptoms, whereas imbalances characterized by excessive parasite growth, exaggerated immune reactions or a combination of both cause severe pathology and death, which is detrimental for both parasite and host. A thorough understanding of the immunological balance of malaria and its relation to other physiological balances in the body is of crucial importance for developing effective interventions to reduce malaria-related morbidity and to diminish fatal outcomes due to severe complications. Therefore, we discuss in this review the detailed mechanisms of anti-malarial immunity, parasite virulence factors including immune evasion mechanisms and pathogenesis. Furthermore, we propose a comprehensive classification of malaria complications according to the different types of imbalances.
Collapse
Affiliation(s)
- Katrien Deroost
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium The Francis Crick Institute, Mill Hill Laboratory, London, NW71AA, UK
| | - Thao-Thy Pham
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Philippe E Van den Steen
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| |
Collapse
|
32
|
Heme-Mediated Induction of CXCL10 and Depletion of CD34+ Progenitor Cells Is Toll-Like Receptor 4 Dependent. PLoS One 2015; 10:e0142328. [PMID: 26555697 PMCID: PMC4640861 DOI: 10.1371/journal.pone.0142328] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/19/2015] [Indexed: 11/19/2022] Open
Abstract
Plasmodium falciparum infection can cause microvascular dysfunction, cerebral encephalopathy and death if untreated. We have previously shown that high concentrations of free heme, and C-X-C motif chemokine 10 (CXCL10) in sera of malaria patients induce apoptosis in microvascular endothelial and neuronal cells contributing to vascular dysfunction, blood-brain barrier (BBB) damage and mortality. Endothelial progenitor cells (EPC) are microvascular endothelial cell precursors partly responsible for repair and regeneration of damaged BBB endothelium. Studies have shown that EPC's are depleted in severe malaria patients, but the mechanisms mediating this phenomenon are unknown. Toll-like receptors recognize a wide variety of pathogen-associated molecular patterns generated by pathogens such as bacteria and parasites. We tested the hypothesis that EPC depletion during malaria pathogenesis is a function of heme-induced apoptosis mediated by CXCL10 induction and toll-like receptor (TLR) activation. Heme and CXCL10 concentrations in plasma obtained from malaria patients were elevated compared with non-malaria subjects. EPC numbers were significantly decreased in malaria patients (P < 0.02) and TLR4 expression was significantly elevated in vivo. These findings were confirmed in EPC precursors in vitro; where it was determined that heme-induced apoptosis and CXCL10 expression was TLR4-mediated. We conclude that increased serum heme mediates depletion of EPC during malaria pathogenesis.
Collapse
|
33
|
Sahu PK, Satpathi S, Behera PK, Mishra SK, Mohanty S, Wassmer SC. Pathogenesis of cerebral malaria: new diagnostic tools, biomarkers, and therapeutic approaches. Front Cell Infect Microbiol 2015; 5:75. [PMID: 26579500 PMCID: PMC4621481 DOI: 10.3389/fcimb.2015.00075] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/05/2015] [Indexed: 12/28/2022] Open
Abstract
Cerebral malaria is a severe neuropathological complication of Plasmodium falciparum infection. It results in high mortality and post-recovery neuro-cognitive disorders in children, even after appropriate treatment with effective anti-parasitic drugs. While the complete landscape of the pathogenesis of cerebral malaria still remains to be elucidated, numerous innovative approaches have been developed in recent years in order to improve the early detection of this neurological syndrome and, subsequently, the clinical care of affected patients. In this review, we briefly summarize the current understanding of cerebral malaria pathogenesis, compile the array of new biomarkers and tools available for diagnosis and research, and describe the emerging therapeutic approaches to tackle this pathology effectively.
Collapse
Affiliation(s)
- Praveen K Sahu
- Center for the Study of Complex Malaria in India, Ispat General Hospital Rourkela, India
| | | | | | - Saroj K Mishra
- Center for the Study of Complex Malaria in India, Ispat General Hospital Rourkela, India
| | - Sanjib Mohanty
- Center for the Study of Complex Malaria in India, Ispat General Hospital Rourkela, India
| | - Samuel Crocodile Wassmer
- Department of Microbiology, New York University School of Medicine New York, NY, USA ; Department of Pathology, The University of Sydney Sydney, NSW, Australia
| |
Collapse
|
34
|
Endothelial-Leukocyte Interaction in Severe Malaria: Beyond the Brain. Mediators Inflamm 2015; 2015:168937. [PMID: 26491221 PMCID: PMC4605361 DOI: 10.1155/2015/168937] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 08/25/2015] [Accepted: 09/01/2015] [Indexed: 01/23/2023] Open
Abstract
Malaria is the most important parasitic disease worldwide, accounting for 1 million deaths each year. Severe malaria is a systemic illness characterized by dysfunction of brain tissue and of one or more peripheral organs as lungs and kidney. The most severe and most studied form of malaria is associated with cerebral complications due to capillary congestion and the adhesion of infected erythrocytes, platelets, and leukocytes to brain vasculature. Thus, leukocyte rolling and adhesion in the brain vascular bed during severe malaria is singular and distinct from other models of inflammation. The leukocyte/endothelium interaction and neutrophil accumulation are also observed in the lungs. However, lung interactions differ from brain interactions, likely due to differences in the blood-brain barrier and blood-air barrier tight junction composition of the brain and lung endothelium. Here, we review the importance of endothelial dysfunction and the mechanism of leukocyte/endothelium interaction during severe malaria. Furthermore, we hypothesize a possible use of adjunctive therapies to antimalarial drugs that target the interaction between the leukocytes and the endothelium.
Collapse
|
35
|
Canavese M, Dottorini T, Crisanti A. VEGF and LPS synergistically silence inflammatory response to Plasmodium berghei infection and protect against cerebral malaria. Pathog Glob Health 2015; 109:255-65. [PMID: 26392042 DOI: 10.1179/2047773215y.0000000018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Malaria infection induces, alongside endothelial damage and obstruction hypoxia, a potent inflammatory response similar to that observed in other systemic diseases caused by bacteria and viruses. Accordingly, it is increasingly recognised that cerebral malaria (CM), the most severe and life threatening complication of Plasmodium falciparum infection, bears a number of similarities with sepsis, an often fatal condition associated with a misregulated inflammatory response triggered by systemic microbial infections. Using a Plasmodium berghei ANKA mouse model, histology, immunohistochemistry and gene expression analysis, we showed that lipopolysaccharide S (LPS), at doses that normally induce inflammation tolerance, protects P. berghei infected mice against experimental CM (ECM). Vascular endothelial growth factor (VEGF) preserved blood vessel integrity, and the combination with LPS resulted in a strong synergistic effect. Treated mice did not develop ECM, showed a prolonged survival and failed to develop a significant inflammatory response and splenomegaly in spite of normal parasite loads. The protective role of VEGF was further confirmed by the observation that the treatment of P. berghei infected C57BL/6 and Balb/c mice with the VEGF receptor inhibitor axitinib exacerbates cerebral pathology and aggravates the course of infection. Infected mice treated with VEGF and LPS showed an induction of the anti-inflammatory genes Nrf2 and HO-1 and a suppression to basal levels of the genes IFN-γ and TNF-α. These results provide the rationale for developing new therapeutic approaches against CM and shed new light on how the inflammatory process can be modulated in the presence of systemic infectious diseases.
Collapse
|
36
|
Carvalho LJDM, Moreira ADS, Daniel-Ribeiro CT, Martins YC. Vascular dysfunction as a target for adjuvant therapy in cerebral malaria. Mem Inst Oswaldo Cruz 2015; 109:577-88. [PMID: 25185000 PMCID: PMC4156451 DOI: 10.1590/0074-0276140061] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 04/02/2014] [Indexed: 12/27/2022] Open
Abstract
Cerebral malaria (CM) is a life-threatening complication of Plasmodium
falciparum malaria that continues to be a major global health problem.
Brain vascular dysfunction is a main factor underlying the pathogenesis of CM and can
be a target for the development of adjuvant therapies for the disease. Vascular
occlusion by parasitised red blood cells and vasoconstriction/vascular dysfunction
results in impaired cerebral blood flow, ischaemia, hypoxia, acidosis and death. In
this review, we discuss the mechanisms of vascular dysfunction in CM and the roles of
low nitric oxide bioavailability, high levels of endothelin-1 and dysfunction of the
angiopoietin-Tie2 axis. We also discuss the usefulness and relevance of the murine
experimental model of CM by Plasmodium berghei ANKA to identify
mechanisms of disease and to screen potential therapeutic interventions.
Collapse
Affiliation(s)
| | - Aline da Silva Moreira
- Laboratório de Pesquisas em Malária, Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, RJ, Brasil
| | | | - Yuri Chaves Martins
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY, USA
| |
Collapse
|
37
|
Barber BE, William T, Grigg MJ, Parameswaran U, Piera KA, Price RN, Yeo TW, Anstey NM. Parasite biomass-related inflammation, endothelial activation, microvascular dysfunction and disease severity in vivax malaria. PLoS Pathog 2015; 11:e1004558. [PMID: 25569250 PMCID: PMC4287532 DOI: 10.1371/journal.ppat.1004558] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 11/06/2014] [Indexed: 12/05/2022] Open
Abstract
Plasmodium vivax can cause severe malaria, however its pathogenesis is poorly understood. In contrast to P. falciparum, circulating vivax parasitemia is low, with minimal apparent sequestration in endothelium-lined microvasculature, and pathogenesis thought unrelated to parasite biomass. However, the relationships between vivax disease-severity and total parasite biomass, endothelial autocrine activation and microvascular dysfunction are unknown. We measured circulating parasitemia and markers of total parasite biomass (plasma parasite lactate dehydrogenase [pLDH] and PvLDH) in adults with severe (n = 9) and non-severe (n = 53) vivax malaria, and examined relationships with disease-severity, endothelial activation, and microvascular function. Healthy controls and adults with non-severe and severe falciparum malaria were enrolled for comparison. Median peripheral parasitemia, PvLDH and pLDH were 2.4-fold, 3.7-fold and 6.9-fold higher in severe compared to non-severe vivax malaria (p = 0.02, p = 0.02 and p = 0.015, respectively), suggesting that, as in falciparum malaria, peripheral P. vivax parasitemia underestimates total parasite biomass, particularly in severe disease. P. vivax schizonts were under-represented in peripheral blood. Severe vivax malaria was associated with increased angiopoietin-2 and impaired microvascular reactivity. Peripheral vivax parasitemia correlated with endothelial activation (angiopoietin-2, von-Willebrand-Factor [VWF], E-selectin), whereas markers of total vivax biomass correlated only with systemic inflammation (IL-6, IL-10). Activity of the VWF-cleaving-protease, ADAMTS13, was deficient in proportion to endothelial activation, IL-6, thrombocytopenia and vivax disease-severity, and associated with impaired microvascular reactivity in severe disease. Impaired microvascular reactivity correlated with lactate in severe vivax malaria. Findings suggest that tissue accumulation of P. vivax may occur, with the hidden biomass greatest in severe disease and capable of mediating systemic inflammatory pathology. The lack of association between total parasite biomass and endothelial activation is consistent with accumulation in parts of the circulation devoid of endothelium. Endothelial activation, associated with circulating parasites, and systemic inflammation may contribute to pathology in vivax malaria, with microvascular dysfunction likely contributing to impaired tissue perfusion.
Collapse
Affiliation(s)
- Bridget E. Barber
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
- Department of Infectious Diseases, Queen Elizabeth Hospital, Sabah, Malaysia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Timothy William
- Department of Infectious Diseases, Queen Elizabeth Hospital, Sabah, Malaysia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Matthew J. Grigg
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
- Department of Infectious Diseases, Queen Elizabeth Hospital, Sabah, Malaysia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Uma Parameswaran
- Department of Infectious Diseases, Queen Elizabeth Hospital, Sabah, Malaysia
- Infectious Diseases Society Sabah-Menzies School of Health Research Clinical Research Unit, Kota Kinabalu, Sabah, Malaysia
| | - Kim A. Piera
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
| | - Ric N. Price
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Tsin W. Yeo
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
- Insitute of Infectious Disease and Epidemiology, Tan Tock Seng Hospital, Singapore
| | - Nicholas M. Anstey
- Global and Tropical Health Division, Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia
- Department of Infectious Diseases, Royal Darwin Hospital, Darwin, Northern Territory, Australia
| |
Collapse
|
38
|
Nacer A, Movila A, Sohet F, Girgis NM, Gundra UM, Loke P, Daneman R, Frevert U. Experimental cerebral malaria pathogenesis--hemodynamics at the blood brain barrier. PLoS Pathog 2014; 10:e1004528. [PMID: 25474413 PMCID: PMC4256476 DOI: 10.1371/journal.ppat.1004528] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 10/17/2014] [Indexed: 12/16/2022] Open
Abstract
Cerebral malaria claims the lives of over 600,000 African children every year. To better understand the pathogenesis of this devastating disease, we compared the cellular dynamics in the cortical microvasculature between two infection models, Plasmodium berghei ANKA (PbA) infected CBA/CaJ mice, which develop experimental cerebral malaria (ECM), and P. yoelii 17XL (PyXL) infected mice, which succumb to malarial hyperparasitemia without neurological impairment. Using a combination of intravital imaging and flow cytometry, we show that significantly more CD8(+) T cells, neutrophils, and macrophages are recruited to postcapillary venules during ECM compared to hyperparasitemia. ECM correlated with ICAM-1 upregulation on macrophages, while vascular endothelia upregulated ICAM-1 during ECM and hyperparasitemia. The arrest of large numbers of leukocytes in postcapillary and larger venules caused microrheological alterations that significantly restricted the venous blood flow. Treatment with FTY720, which inhibits vascular leakage, neurological signs, and death from ECM, prevented the recruitment of a subpopulation of CD45(hi) CD8(+) T cells, ICAM-1(+) macrophages, and neutrophils to postcapillary venules. FTY720 had no effect on the ECM-associated expression of the pattern recognition receptor CD14 in postcapillary venules suggesting that endothelial activation is insufficient to cause vascular pathology. Expression of the endothelial tight junction proteins claudin-5, occludin, and ZO-1 in the cerebral cortex and cerebellum of PbA-infected mice with ECM was unaltered compared to FTY720-treated PbA-infected mice or PyXL-infected mice with hyperparasitemia. Thus, blood brain barrier opening does not involve endothelial injury and is likely reversible, consistent with the rapid recovery of many patients with CM. We conclude that the ECM-associated recruitment of large numbers of activated leukocytes, in particular CD8(+) T cells and ICAM(+) macrophages, causes a severe restriction in the venous blood efflux from the brain, which exacerbates the vasogenic edema and increases the intracranial pressure. Thus, death from ECM could potentially occur as a consequence of intracranial hypertension.
Collapse
Affiliation(s)
- Adéla Nacer
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Alexandru Movila
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Fabien Sohet
- Department of Anatomy, University of California San Francisco, San Francisco, California, United States of America
| | - Natasha M. Girgis
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Uma Mahesh Gundra
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - P'ng Loke
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
| | - Richard Daneman
- Department of Anatomy, University of California San Francisco, San Francisco, California, United States of America
| | - Ute Frevert
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, New York, New York, United States of America
- * E-mail:
| |
Collapse
|
39
|
|
40
|
Gomes LT, Alves-Junior ER, Rodrigues-Jesus C, Nery AF, Gasquez-Martin TO, Fontes CJ. Angiopoietin-2 and angiopoietin-2/angiopoietin-1 ratio as indicators of potential severity of Plasmodium vivax malaria in patients with thrombocytopenia. PLoS One 2014; 9:e109246. [PMID: 25275496 PMCID: PMC4183553 DOI: 10.1371/journal.pone.0109246] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 09/10/2014] [Indexed: 12/13/2022] Open
Abstract
Introduction Angiogenic factors such as angiopoietin 1 (Ang-1) and angiopoietin 2 (Ang-2) are biomarkers produced during activation and dysfunction of the vascular endothelium in several infectious diseases. The aim of this study was to determine the serum levels of Ang-1 and Ang-2 and to establish their relationship with the main indicators of worst-case prognosis in patients with P. vivax malaria. Methods This is a retrospective case-control study nested within a cohort of symptomatic malaria patients. A potentially severe case was defined as a patient that presented at least one of the main indicators of the worst-case prognosis for falciparum malaria, as established by the World Health Organization. Ang-2 and Ang-1 and the Ang-2/Ang-1 ratio were used to analyze the role of angiopoietins as biomarkers in signaling potentially severe vivax malaria. ROC curves were generated to identify a cut-off point discriminating between the angiopoietin concentrations that were most strongly associated with potential infection severity. Results The serum levels of Ang-2 and the Ang-2/Ang-1 ratio were higher in the case group. In contrast, the serum levels of Ang-1 were lower in the cases than in the control patients. The blood count for platelets showed a positive correlation with Ang-1 and a negative correlation with Ang-2 and with the Ang-2/Ang-1 ratio. The area under the ROC curve (AUC) for serum angiopoietins, as an indicator of worst-case prognosis in a potentially severe P. vivax malarial infection, was larger in the subgroup of patients with platelet counts <75,000/µL. Conclusion This study showed that patients with predictors of worst-case prognoses for P. vivax malaria have lower Ang-1 and higher Ang-2 serum levels (and higher values for the Ang-2/Ang-1 ratio) than controls. Elevated serum levels of Ang-2 and high values for the Ang-2/Ang-1 ratio may potentially be used as predictors of worst-case prognoses for P. vivax malaria, especially in patients with thrombocytopenia.
Collapse
Affiliation(s)
- Luciano Teixeira Gomes
- Hospital Julio Müller, Federal University of Mato Grosso, Cuiabá, Brazil
- Univag University Centre, Varzea Grande, Brazil
- Facimed Cacoal Faculty of Medicine, Cacoal, Brazil
| | | | | | - Andreia Ferreira Nery
- Hospital Julio Müller, Federal University of Mato Grosso, Cuiabá, Brazil
- Facimed Cacoal Faculty of Medicine, Cacoal, Brazil
| | | | - Cor Jesus Fontes
- Hospital Julio Müller, Federal University of Mato Grosso, Cuiabá, Brazil
- * E-mail:
| |
Collapse
|
41
|
Storm J, Craig AG. Pathogenesis of cerebral malaria--inflammation and cytoadherence. Front Cell Infect Microbiol 2014; 4:100. [PMID: 25120958 PMCID: PMC4114466 DOI: 10.3389/fcimb.2014.00100] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/07/2014] [Indexed: 01/08/2023] Open
Abstract
Despite decades of research on cerebral malaria (CM) there is still a paucity of knowledge about what actual causes CM and why certain people develop it. Although sequestration of P. falciparum infected red blood cells has been linked to pathology, it is still not clear if this is directly or solely responsible for this clinical syndrome. Recent data have suggested that a combination of parasite variant types, mainly defined by the variant surface antigen, P. falciparum erythrocyte membrane protein 1 (PfEMP1), its receptors, coagulation and host endothelial cell activation (or inflammation) are equally important. This makes CM a multi-factorial disease and a challenge to unravel its causes to decrease its detrimental impact.
Collapse
Affiliation(s)
- Janet Storm
- Department of Parasitology, Liverpool School of Tropical Medicine Liverpool, UK ; Malawi Liverpool Wellcome Trust Clinical Research Programme (MLW), University of Malawi College of Medicine Blantyre, Malawi
| | - Alister G Craig
- Department of Parasitology, Liverpool School of Tropical Medicine Liverpool, UK
| |
Collapse
|
42
|
Hempel C, Hoyer N, Kildemoes A, Jendresen CB, Kurtzhals JAL. Systemic and Cerebral Vascular Endothelial Growth Factor Levels Increase in Murine Cerebral Malaria along with Increased Calpain and Caspase Activity and Can be Reduced by Erythropoietin Treatment. Front Immunol 2014; 5:291. [PMID: 24995009 PMCID: PMC4062992 DOI: 10.3389/fimmu.2014.00291] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 06/03/2014] [Indexed: 12/20/2022] Open
Abstract
The pathogenesis of cerebral malaria (CM) includes compromised microvascular perfusion, increased inflammation, cytoadhesion, and endothelial activation. These events cause blood-brain barrier disruption and neuropathology and associations with the vascular endothelial growth factor (VEGF) signaling pathway have been shown. We studied this pathway in mice infected with Plasmodium berghei ANKA causing murine CM with or without the use of erythropoietin (EPO) as adjunct therapy. ELISA and western blotting was used for quantification of VEGF and relevant proteins in brain and plasma. CM increased levels of VEGF in brain and plasma and decreased plasma levels of soluble VEGF receptor 2. EPO treatment normalized VEGF receptor 2 levels and reduced brain VEGF levels. Hypoxia-inducible factor (HIF)-1α was significantly upregulated whereas cerebral HIF-2α and EPO levels remained unchanged. Furthermore, we noticed increased caspase-3 and calpain activity in terminally ill mice, as measured by protease-specific cleavage of α-spectrin and p35. In conclusion, we detected increased cerebral and systemic VEGF as well as HIF-1α, which in the brain were reduced to normal in EPO-treated mice. Also caspase and calpain activity was reduced markedly in EPO-treated mice.
Collapse
Affiliation(s)
- Casper Hempel
- Centre for Medical Parasitology, Department of Clinical Microbiology, Copenhagen University Hospital , Copenhagen , Denmark ; Department of International Health, Immunology and Microbiology, University of Copenhagen , Copenhagen , Denmark
| | - Nils Hoyer
- Centre for Medical Parasitology, Department of Clinical Microbiology, Copenhagen University Hospital , Copenhagen , Denmark ; Department of International Health, Immunology and Microbiology, University of Copenhagen , Copenhagen , Denmark
| | - Anna Kildemoes
- Centre for Medical Parasitology, Department of Clinical Microbiology, Copenhagen University Hospital , Copenhagen , Denmark ; Department of International Health, Immunology and Microbiology, University of Copenhagen , Copenhagen , Denmark
| | - Charlotte Bille Jendresen
- Centre for Medical Parasitology, Department of Clinical Microbiology, Copenhagen University Hospital , Copenhagen , Denmark ; Department of International Health, Immunology and Microbiology, University of Copenhagen , Copenhagen , Denmark
| | - Jørgen Anders Lindholm Kurtzhals
- Centre for Medical Parasitology, Department of Clinical Microbiology, Copenhagen University Hospital , Copenhagen , Denmark ; Department of International Health, Immunology and Microbiology, University of Copenhagen , Copenhagen , Denmark
| |
Collapse
|
43
|
Frevert U, Nacer A. Immunobiology of Plasmodium in liver and brain. Parasite Immunol 2014; 35:267-82. [PMID: 23631610 DOI: 10.1111/pim.12039] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 04/17/2013] [Indexed: 12/11/2022]
Abstract
Malaria remains one of the most serious health problems globally, but our understanding of the biology of the parasite and the pathogenesis of severe disease is still limited. Multiple cellular effector mechanisms that mediate parasite elimination from the liver have been described, but how effector cells use classical granule-mediated cytotoxicity to attack infected hepatocytes and how cytokines and chemokines spread via the unique fluid pathways of the liver to reach the parasites over considerable distances remains unknown. Similarly, a wealth of information on cerebral malaria (CM), one of the most severe manifestations of the disease, was gained from post-mortem analyses of human brain and murine disease models, but the cellular processes that ultimately cause disease are not fully understood. Here, we discuss how imaging of the local dynamics of parasite infection and host response as well as consideration of anatomical and physiological features of liver and brain can provide a better understanding of the initial asymptomatic hepatic phase of the infection and the cascade of events leading to CM. Given the increasing drug resistance of both parasite and vector and the unavailability of a protective vaccine, the urgency to reduce the tremendous morbidity and mortality associated with severe malaria is obvious.
Collapse
Affiliation(s)
- U Frevert
- Division of Medical Parasitology, Department of Microbiology, New York University School of Medicine, New York, NY 10010, USA.
| | | |
Collapse
|
44
|
Solomon W, Wilson NO, Anderson L, Pitts S, Patrickson J, Liu M, Ford BD, Stiles JK. Neuregulin-1 attenuates mortality associated with experimental cerebral malaria. J Neuroinflammation 2014; 11:9. [PMID: 24433482 PMCID: PMC3906904 DOI: 10.1186/1742-2094-11-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/23/2013] [Indexed: 12/17/2022] Open
Abstract
Background Cerebral Malaria (CM) is a diffuse encephalopathy caused by Plasmodium falciparum infection. Despite availability of antimalarial drugs, CM-associated mortality remains high at approximately 30% and a subset of survivors develop neurological and cognitive disabilities. While antimalarials are effective at clearing Plasmodium parasites they do little to protect against CM pathophysiology and parasite-induced brain inflammation that leads to seizures, coma and long-term neurological sequelae in CM patients. Thus, there is urgent need to explore therapeutics that can reduce or prevent CM pathogenesis and associated brain inflammation to improve survival. Neuregulin-1 (NRG-1) is a neurotrophic growth factor shown to protect against brain injury associated with acute ischemic stroke (AIS) and neurotoxin exposure. However, this drug has not been tested against CM-associated brain injury. Since CM-associated brain injuries and AIS share similar pathophysiological features, we hypothesized that NRG-1 will reduce or prevent neuroinflammation and brain damage as well as improve survival in mice with late-stage experimental cerebral malaria (ECM). Methods We tested the effects of NRG-1 on ECM-associated brain inflammation and mortality in P. berghei ANKA (PbA)-infected mice and compared to artemether (ARM) treatment; an antimalarial currently used in various combination therapies against malaria. Results Treatment with ARM (25 mg/kg/day) effectively cleared parasites and reduced mortality in PbA-infected mice by 82%. Remarkably, NRG-1 therapy (1.25 ng/kg/day) significantly improved survival against ECM by 73% despite increase in parasite burden within NRG-1-treated mice. Additionally, NRG-1 therapy reduced systemic and brain pro-inflammatory factors TNFalpha, IL-6, IL-1alpha and CXCL10 and enhanced anti-inflammatory factors, IL-5 and IL-13 while decreasing leukocyte accumulation in brain microvessels. Conclusions This study suggests that NRG-1 attenuates ECM-associated brain inflammation and injuries and may represent a novel supportive therapy for the management of CM.
Collapse
Affiliation(s)
- Wesley Solomon
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA.
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Liles WC, Kain KC. Endothelial activation and dysfunction in the pathogenesis of microvascular obstruction in severe malaria--a viable target for therapeutic adjunctive intervention. J Infect Dis 2014; 210:163-4. [PMID: 24443542 DOI: 10.1093/infdis/jiu035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
46
|
Frevert U, Nacer A, Cabrera M, Movila A, Leberl M. Imaging Plasmodium immunobiology in the liver, brain, and lung. Parasitol Int 2013; 63:171-86. [PMID: 24076429 DOI: 10.1016/j.parint.2013.09.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 08/28/2013] [Accepted: 09/18/2013] [Indexed: 01/10/2023]
Abstract
Plasmodium falciparum malaria is responsible for the deaths of over half a million African children annually. Until a decade ago, dynamic analysis of the malaria parasite was limited to in vitro systems with the typical limitations associated with 2D monocultures or entirely artificial surfaces. Due to extremely low parasite densities, the liver was considered a black box in terms of Plasmodium sporozoite invasion, liver stage development, and merozoite release into the blood. Further, nothing was known about the behavior of blood stage parasites in organs such as the brain where clinical signs manifest and the ensuing immune response of the host that may ultimately result in a fatal outcome. The advent of fluorescent parasites, advances in imaging technology, and availability of an ever-increasing number of cellular and molecular probes have helped illuminate many steps along the pathogenetic cascade of this deadly tropical parasite.
Collapse
Affiliation(s)
- Ute Frevert
- Division of Medical Parasitology, Department of Microbiology, New York University School of Medicine, 341 E 25 Street, New York, NY 10010, USA.
| | | | | | | | | |
Collapse
|
47
|
Ong SP, Ng ML, Chu JJH. Differential regulation of angiopoietin 1 and angiopoietin 2 during dengue virus infection of human umbilical vein endothelial cells: implications for endothelial hyperpermeability. Med Microbiol Immunol 2013; 202:437-52. [DOI: 10.1007/s00430-013-0310-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 08/19/2013] [Indexed: 12/17/2022]
|
48
|
Hawkes M, Elphinstone RE, Conroy AL, Kain KC. Contrasting pediatric and adult cerebral malaria: the role of the endothelial barrier. Virulence 2013; 4:543-55. [PMID: 23924893 PMCID: PMC5359751 DOI: 10.4161/viru.25949] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Malaria affects millions of people around the world and a small subset of those infected develop cerebral malaria. The clinical presentation of cerebral malaria differs between children and adults, and it has been suggested that age-related changes in the endothelial response may account for some of these differences. During cerebral malaria, parasites sequester within the brain microvasculature but do not penetrate into the brain parenchyma and yet, the infection causes severe neurological symptoms. Endothelial dysfunction is thought to play an important role in mediating these adverse clinical outcomes. During infection, the endothelium becomes activated and more permeable, which leads to increased inflammation, hemorrhages, and edema in the surrounding tissue. We hypothesize that post-natal developmental changes, occurring in both endothelial response and the neurovascular unit, account for the differences observed in the clinical presentations of cerebral malaria in children compared with adults.
Collapse
|
49
|
Platelet activation determines angiopoietin-1 and VEGF levels in malaria: implications for their use as biomarkers. PLoS One 2013; 8:e64850. [PMID: 23755151 PMCID: PMC3670845 DOI: 10.1371/journal.pone.0064850] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 04/19/2013] [Indexed: 01/28/2023] Open
Abstract
Introduction The angiogenic proteins angiopoietin (Ang)-1, Ang-2 and vascular endothelial growth factor (VEGF) are regulators of endothelial inflammation and integrity. Since platelets store large amounts of Ang-1 and VEGF, measurement of circulation levels of these proteins is sensitive to platelet number, in vivo platelet activation and inadvertent platelet activation during blood processing. We studied plasma Ang-1, Ang-2 and VEGF levels in malaria patients, taking the necessary precautions to avoid ex vivo platelet activation, and related plasma levels to platelet count and the soluble platelet activation markers P-selectin and CXCL7. Methods Plasma levels of Ang-1, Ang-2, VEGF, P-selectin and CXCL7 were measured in CTAD plasma, minimizing ex vivo platelet activation, in 27 patients with febrile Plasmodium falciparum malaria at presentation and day 2 and 5 of treatment and in 25 healthy controls. Results Levels of Ang-1, Ang-2 and VEGF were higher at day 0 in malaria patients compared to healthy controls. Ang-2 levels, which is a marker of endothelial activation, decreased after start of antimalarial treatment. In contrast, Ang-1 and VEGF plasma levels increased and this corresponded with the increase in platelet number. Soluble P-selectin and CXCL7 levels followed the same trend as Ang-1 and VEGF levels. Plasma levels of these four proteins correlated strongly in malaria patients, but only moderately in controls. Conclusion In contrast to previous studies, we found elevated plasma levels of Ang-1 and VEGF in patients with malaria resulting from in vivo platelet activation. Ang-1 release from platelets may be important to dampen the disturbing effects of Ang-2 on the endothelium. Evaluation of plasma levels of these angiogenic proteins requires close adherence to a stringent protocol to minimize ex vivo platelet activation.
Collapse
|
50
|
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.
Collapse
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
| |
Collapse
|