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Walker IS, Rogerson SJ. Pathogenicity and virulence of malaria: Sticky problems and tricky solutions. Virulence 2023; 14:2150456. [PMID: 36419237 PMCID: PMC9815252 DOI: 10.1080/21505594.2022.2150456] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 11/25/2022] Open
Abstract
Infections with Plasmodium falciparum and Plasmodium vivax cause over 600,000 deaths each year, concentrated in Africa and in young children, but much of the world's population remain at risk of infection. In this article, we review the latest developments in the immunogenicity and pathogenesis of malaria, with a particular focus on P. falciparum, the leading malaria killer. Pathogenic factors include parasite-derived toxins and variant surface antigens on infected erythrocytes that mediate sequestration in the deep vasculature. Host response to parasite toxins and to variant antigens is an important determinant of disease severity. Understanding how parasites sequester, and how antibody to variant antigens could prevent sequestration, may lead to new approaches to treat and prevent disease. Difficulties in malaria diagnosis, drug resistance, and specific challenges of treating P. vivax pose challenges to malaria elimination, but vaccines and other preventive strategies may offer improved disease control.
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Affiliation(s)
- Isobel S Walker
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
| | - Stephen J Rogerson
- Department of Infectious Diseases, The University of Melbourne, The Doherty Institute, Melbourne, Australia
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Oriá RB, Freitas RS, Roque CR, Nascimento JCR, Silva AP, Malva JO, Guerrant RL, Vitek MP. ApoE Mimetic Peptides to Improve the Vicious Cycle of Malnutrition and Enteric Infections by Targeting the Intestinal and Blood-Brain Barriers. Pharmaceutics 2023; 15:pharmaceutics15041086. [PMID: 37111572 PMCID: PMC10141726 DOI: 10.3390/pharmaceutics15041086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
Apolipoprotein E (apoE) mimetic peptides are engineered fragments of the native apoE protein’s LDL-receptor binding site that improve the outcomes following a brain injury and intestinal inflammation in a variety of models. The vicious cycle of enteric infections and malnutrition is closely related to environmental-driven enteric dysfunction early in life, and such chronic inflammatory conditions may blunt the developmental trajectories of children with worrisome and often irreversible physical and cognitive faltering. This window of time for microbiota maturation and brain plasticity is key to protecting cognitive domains, brain health, and achieving optimal/full developmental potential. This review summarizes the potential role of promising apoE mimetic peptides to improve the function of the gut-brain axis, including targeting the blood-brain barrier in children afflicted with malnutrition and enteric infections.
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Affiliation(s)
- Reinaldo B. Oriá
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology, School of Medicine, Institute of Biomedicine, Federal University of Ceara, Fortaleza 60430-270, Brazil
- Correspondence: ; Tel.: +55-85-3366-8239
| | - Raul S. Freitas
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology, School of Medicine, Institute of Biomedicine, Federal University of Ceara, Fortaleza 60430-270, Brazil
| | - Cássia R. Roque
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology, School of Medicine, Institute of Biomedicine, Federal University of Ceara, Fortaleza 60430-270, Brazil
| | - José Carlos R. Nascimento
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology, School of Medicine, Institute of Biomedicine, Federal University of Ceara, Fortaleza 60430-270, Brazil
- Institute of Health Sciences, Medicine, University of International Integration of Afro-Brazilian Lusofonia, Redenção 62790-970, Brazil
| | - Ana Paula Silva
- Institute of Pharmacology and Experimental Therapeutics and Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine and Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - João O. Malva
- Institute of Pharmacology and Experimental Therapeutics and Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine and Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, 3000-548 Coimbra, Portugal
| | - Richard L. Guerrant
- Division of Infectious Diseases and International Health, Department of Medicine, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Michael P. Vitek
- Division of Neurology, Duke University Medical Center, Durham, NC 27710, USA
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Abuga KM, Nairz M, MacLennan CA, Atkinson SH. Severe anaemia, iron deficiency, and susceptibility to invasive bacterial infections. Wellcome Open Res 2023; 8:48. [PMID: 37600584 PMCID: PMC10439361 DOI: 10.12688/wellcomeopenres.18829.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2023] [Indexed: 08/22/2023] Open
Abstract
Severe anaemia and invasive bacterial infections remain important causes of hospitalization and death among young African children. The emergence and spread of antimicrobial resistance demand better understanding of bacteraemia risk factors to inform prevention strategies. Epidemiological studies have reported an association between severe anaemia and bacteraemia. In this review, we explore evidence that severe anaemia is associated with increased risk of invasive bacterial infections in young children. We describe mechanisms of iron dysregulation in severe anaemia that might contribute to increased risk and pathogenesis of invasive bacteria, recent advances in knowledge of how iron deficiency and severe anaemia impair immune responses to bacterial infections and vaccines, and the gaps in our understanding of mechanisms underlying severe anaemia, iron deficiency, and the risk of invasive bacterial infections.
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Affiliation(s)
- Kelvin M. Abuga
- Kenya Medical Research Institute (KEMRI) Centre for Geographical Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
- Open University, KEMRI-Wellcome Trust Research Programme – Accredited Research Centre, Kilifi, 80108, Kenya
| | - Manfred Nairz
- Department of Internal Medicine II, Medical University of Innsbruck, Innsbruck, 6020, Austria
| | - Calman A. MacLennan
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7DQ, UK
| | - Sarah H. Atkinson
- Kenya Medical Research Institute (KEMRI) Centre for Geographical Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kilifi, 80108, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7LG, UK
- Department of Paediatrics, University of Oxford, Oxford, OX3 9DU, UK
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Mahamar A, Gonzales Hurtado PA, Morrison R, Boone R, Attaher O, Diarra BS, Gaoussou S, Issiaka D, Dicko A, Duffy PE, Fried M. Plasma biomarkers of hemoglobin loss in Plasmodium falciparum-infected children identified by quantitative proteomics. Blood 2022; 139:2361-2376. [PMID: 34871370 PMCID: PMC9012130 DOI: 10.1182/blood.2021014045] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 11/23/2021] [Indexed: 11/20/2022] Open
Abstract
Anemia is common among young children infected with Plasmodium falciparum and severe malarial anemia (SMA) is a major cause of their mortality. Two major mechanisms cause malarial anemia: hemolysis of uninfected as well as infected erythrocytes and insufficient erythropoiesis. In a longitudinal birth cohort in Mali, we commonly observed marked hemoglobin reductions during P falciparum infections with a small proportion that progressed to SMA. We sought biomarkers of these processes using quantitative proteomic analysis on plasma samples from 9 P falciparum-infected children, comparing those with reduced hemoglobin (with or without SMA) vs those with stable hemoglobin. We identified higher plasma levels of circulating 20S proteasome and lower insulin-like growth factor-1 (IGF-1) levels in children with reduced hemoglobin. We confirmed these findings in independent enzyme-linked immunosorbent assay-based validation studies of subsets of children from the same cohort (20S proteasome, N = 71; IGF-1, N = 78). We speculate that circulating 20S proteasome plays a role in digesting erythrocyte membrane proteins modified by oxidative stress, resulting in hemolysis, whereas decreased IGF-1, a critical factor for erythroid maturation, might contribute to insufficient erythropoiesis. Quantitative plasma proteomics identified soluble mediators that may contribute to the major mechanisms underlying malarial anemia. This study was registered at www.clinicaltrials.gov as #NCT01168271.
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Affiliation(s)
- Almahamoudou Mahamar
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali; and
| | | | - Robert Morrison
- Pathogenesis and Immunity Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - Rachel Boone
- Molecular Pathogenesis and Biomarkers Section and
| | - Oumar Attaher
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali; and
| | - Bacary S Diarra
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali; and
| | - Santara Gaoussou
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali; and
| | - Djibrilla Issiaka
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali; and
| | - Alassane Dicko
- Malaria Research and Training Center, Faculty of Medicine, Pharmacy and Dentistry, University of Sciences Techniques and Technologies of Bamako, Bamako, Mali; and
| | - Patrick E Duffy
- Pathogenesis and Immunity Section, Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD
| | - Michal Fried
- Molecular Pathogenesis and Biomarkers Section and
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Pelkonen T, Roine I, Kallio M, Jahnukainen K, Peltola H. Prevalence and significance of anaemia in childhood bacterial meningitis: a secondary analysis of prospectively collected data from clinical trials in Finland, Latin America and Angola. BMJ Open 2022; 12:e057285. [PMID: 35288394 PMCID: PMC8921951 DOI: 10.1136/bmjopen-2021-057285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVES To describe the prevalence and severity of anaemia and to examine its associations with outcome in children with bacterial meningitis (BM). DESIGN Secondary analysis of descriptive data from five randomised BM treatment trials. SETTING Hospitals in Finland, Latin America and Angola. PARTICIPANTS Consecutive children from 2 months to 15 years of age admitted with BM and who had haemoglobin (Hb) measured on admission. OUTCOME MEASURES Prevalence and degree of anaemia using the WHO criteria, and their associations with recovery with sequelae or death. RESULTS The median Hb was 11.8 g/dL in Finland (N=341), 9.2 g/dL in Latin America (N=597) and 7.6 g/dL in Angola (N=1085). Of the children, 79% had anaemia, which was severe in 29%, moderate in 58% and mild in 13% of cases. Besides study area, having anaemia was independently associated with age <1 year, treatment delay >3 days, weight-for-age z-score <-3 and other than meningococcal aetiology. Irrespective of the study area, anaemia correlated with the markers of disease severity. In children with severe to moderate anaemia (vs mild or no anaemia), the risk ratio for death was 3.38 and for death or severe sequelae was 3.07. CONCLUSION Anaemia, mostly moderate, was common in children with BM, especially in Angola, in underweight children, among those with treatment delay, and in pneumococcal meningitis. Poor outcome was associated with anaemia in all three continents. TRIAL REGISTRATION NUMBER The registration numbers of Angolan trials were ISRCTN62824827 and NCT01540838.
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Affiliation(s)
- Tuula Pelkonen
- New Children's Hospital, Helsinki University Hospital, Helsinki, Finland
- Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Pediatric Research Center, Helsinki, Finland
- Hospital Pediátrico David Bernardino, Luanda, Angola
| | - Irmeli Roine
- Faculty of Medicine, University Diego Portales, Santiago, Chile
| | - Markku Kallio
- Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kirsi Jahnukainen
- New Children's Hospital, Helsinki University Hospital, Helsinki, Finland
- Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Pediatric Research Center, Helsinki, Finland
| | - Heikki Peltola
- Faculty of Medicine, University of Helsinki, Helsinki, Finland
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Decreased parasite burden and altered host response in children with sickle cell anemia and severe anemia with malaria. Blood Adv 2021; 5:4710-4720. [PMID: 34470050 PMCID: PMC8759120 DOI: 10.1182/bloodadvances.2021004704] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/21/2021] [Indexed: 11/20/2022] Open
Abstract
Plasmodium falciparum malaria causes morbidity and mortality in African children with sickle cell anemia (SCA), but comparisons of host responses to P falciparum between children with SCA (homozygous sickle cell disease/hemoglobin SS [HbSS]) and normal hemoglobin genotype/hemoglobin AA (HbAA) are limited. We assessed parasite biomass and plasma markers of inflammation and endothelial activation in children with HbAA (n = 208) or HbSS (n = 22) who presented with severe anemia and P falciparum parasitemia to Mulago Hospital in Kampala, Uganda. Genotyping was performed at study completion. No child had known SCA at enrollment. Children with HbSS did not differ from children with HbAA in peripheral parasite density, but had significantly lower sequestered parasite biomass. Children with HbSS had greater leukocytosis but significantly lower concentrations of several plasma inflammatory cytokines, including tumor necrosis factor α (TNF-α). In contrast, children with HbSS had threefold greater concentrations of angiopoietin-2 (Angpt-2), a marker of endothelial dysregulation associated with mortality in severe malaria. Lower TNF-α concentrations were associated with increased risk of postdischarge mortality or readmission, whereas higher Angpt-2 concentrations were associated with increased risk of recurrent clinical malaria. Children with SCA have decreased parasite sequestration and inflammation but increased endothelial dysregulation during severe anemia with P falciparum parasitemia, which may ameliorate acute infectious complications but predispose to harmful long-term sequelae.
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