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DeMichele E, Sosnowski O, Buret AG, Allain T. Regulatory Functions of Hypoxia in Host-Parasite Interactions: A Focus on Enteric, Tissue, and Blood Protozoa. Microorganisms 2023; 11:1598. [PMID: 37375100 PMCID: PMC10303274 DOI: 10.3390/microorganisms11061598] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
Body tissues are subjected to various oxygenic gradients and fluctuations and hence can become transiently hypoxic. Hypoxia-inducible factor (HIF) is the master transcriptional regulator of the cellular hypoxic response and is capable of modulating cellular metabolism, immune responses, epithelial barrier integrity, and local microbiota. Recent reports have characterized the hypoxic response to various infections. However, little is known about the role of HIF activation in the context of protozoan parasitic infections. Growing evidence suggests that tissue and blood protozoa can activate HIF and subsequent HIF target genes in the host, helping or hindering their pathogenicity. In the gut, enteric protozoa are adapted to steep longitudinal and radial oxygen gradients to complete their life cycle, yet the role of HIF during these protozoan infections remains unclear. This review focuses on the hypoxic response to protozoa and its role in the pathophysiology of parasitic infections. We also discuss how hypoxia modulates host immune responses in the context of protozoan infections.
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Affiliation(s)
- Emily DeMichele
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (E.D.); (O.S.); (A.G.B.)
- Inflammation Research Network, University of Calgary, Calgary, AB T2N 1N4, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Olivia Sosnowski
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (E.D.); (O.S.); (A.G.B.)
- Inflammation Research Network, University of Calgary, Calgary, AB T2N 1N4, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Andre G. Buret
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (E.D.); (O.S.); (A.G.B.)
- Inflammation Research Network, University of Calgary, Calgary, AB T2N 1N4, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Thibault Allain
- Department of Biological Sciences, University of Calgary, Calgary, AB T2N 1N4, Canada; (E.D.); (O.S.); (A.G.B.)
- Inflammation Research Network, University of Calgary, Calgary, AB T2N 1N4, Canada
- Host-Parasite Interactions, University of Calgary, Calgary, AB T2N 1N4, Canada
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Akide Ndunge OB, Kilian N, Salman MM. Cerebral Malaria and Neuronal Implications of Plasmodium Falciparum Infection: From Mechanisms to Advanced Models. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202944. [PMID: 36300890 PMCID: PMC9798991 DOI: 10.1002/advs.202202944] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 09/22/2022] [Indexed: 06/01/2023]
Abstract
Reorganization of host red blood cells by the malaria parasite Plasmodium falciparum enables their sequestration via attachment to the microvasculature. This artificially increases the dwelling time of the infected red blood cells within inner organs such as the brain, which can lead to cerebral malaria. Cerebral malaria is the deadliest complication patients infected with P. falciparum can experience and still remains a major public health concern despite effective antimalarial therapies. Here, the current understanding of the effect of P. falciparum cytoadherence and their secreted proteins on structural features of the human blood-brain barrier and their involvement in the pathogenesis of cerebral malaria are highlighted. Advanced 2D and 3D in vitro models are further assessed to study this devastating interaction between parasite and host. A better understanding of the molecular mechanisms leading to neuronal and cognitive deficits in cerebral malaria will be pivotal in devising new strategies to treat and prevent blood-brain barrier dysfunction and subsequent neurological damage in patients with cerebral malaria.
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Affiliation(s)
- Oscar Bate Akide Ndunge
- Department of Internal MedicineSection of Infectious DiseasesYale University School of Medicine300 Cedar StreetNew HavenCT06510USA
| | - Nicole Kilian
- Centre for Infectious Diseases, ParasitologyHeidelberg University HospitalIm Neuenheimer Feld 32469120HeidelbergGermany
| | - Mootaz M. Salman
- Department of PhysiologyAnatomy and GeneticsUniversity of OxfordOxfordOX1 3QUUK
- Kavli Institute for NanoScience DiscoveryUniversity of OxfordOxfordUK
- Oxford Parkinson's Disease CentreUniversity of OxfordOxfordUK
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Pham TT, Verheijen M, Vandermosten L, Deroost K, Knoops S, Van den Eynde K, Boon L, Janse CJ, Opdenakker G, Van den Steen PE. Pathogenic CD8 + T Cells Cause Increased Levels of VEGF-A in Experimental Malaria-Associated Acute Respiratory Distress Syndrome, but Therapeutic VEGFR Inhibition Is Not Effective. Front Cell Infect Microbiol 2017; 7:416. [PMID: 29034214 PMCID: PMC5627041 DOI: 10.3389/fcimb.2017.00416] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 09/06/2017] [Indexed: 12/29/2022] Open
Abstract
Malaria is a severe disease and kills over 400,000 people each year. Malarial complications are the main cause of death and include cerebral malaria and malaria-associated acute respiratory distress syndrome (MA-ARDS). Despite antimalarial treatment, lethality rates of MA-ARDS are still between 20 and 80%. Patients develop pulmonary edema with hemorrhages and leukocyte extravasation in the lungs. The vascular endothelial growth factor-A (VEGF-A) and the placental growth factor (PlGF) are vascular permeability factors and may be involved in the disruption of the alveolar-capillary membrane, leading to alveolar edema. We demonstrated increased pulmonary VEGF-A and PlGF levels in lungs of mice with experimental MA-ARDS. Depletion of pathogenic CD8+ T cells blocked pulmonary edema and abolished the increase of VEGF-A and PlGF. However, neutralization of VEGF receptor-2 (VEGFR-2) with the monoclonal antibody clone DC101 did not decrease pulmonary pathology. The broader spectrum receptor tyrosine kinase inhibitor sunitinib even increased lung pathology. These data suggest that the increase in alveolar VEGF-A and PlGF is not a cause but rather a consequence of the pulmonary pathology in experimental MA-ARDS and that therapeutic inhibition of VEGF receptors is not effective and even contra-indicated.
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Affiliation(s)
- Thao-Thy Pham
- Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven-University of LeuvenLeuven, Belgium
| | - Melissa Verheijen
- Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven-University of LeuvenLeuven, Belgium
| | - Leen Vandermosten
- Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven-University of LeuvenLeuven, Belgium
| | - Katrien Deroost
- Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven-University of LeuvenLeuven, Belgium
| | - Sofie Knoops
- Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven-University of LeuvenLeuven, Belgium
| | | | | | - Chris J Janse
- Leiden Malaria Research Group, Department of Parasitology, Leiden University Medical CenterLeiden, Netherlands
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven-University of LeuvenLeuven, Belgium
| | - Philippe E Van den Steen
- Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven-University of LeuvenLeuven, Belgium
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Age-dependent expression of VEGFR2 in deep brain arteries in small vessel disease, CADASIL, and healthy brains. Neurobiol Aging 2016; 42:110-5. [PMID: 27143427 DOI: 10.1016/j.neurobiolaging.2016.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 02/16/2016] [Accepted: 03/02/2016] [Indexed: 01/07/2023]
Abstract
Vascular myocytes are central to brain aging. Small vessel disease (SVD; arteriolosclerosis) is a widespread cause of lacunar stroke and vascular dementia and is characterized by fibrosis and depletion of vascular myocytes in small penetrating arteries. Vascular endothelial growth factor (VEGF) is associated with brain aging, and Immunolabeling for vascular endothelial growth factor receptor 2 (VEGFR2) is a potent determinant of cell fate. Here, we tested whether VEGFR2 in vascular myocytes is associated with older age and SVD in human brain. Immunolabeling for VEGFR2 in deep gray matter was assessed in older people with or without moderate-severe SVD or in younger people without brain pathology or with a monogenic form of SVD (Cerebral Autosomal-Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy). All cases were without Alzheimer's disease pathology. Myocyte VEGFR2 was associated with increasing age (p = 0.0026) but not with SVD pathology or with sclerotic index or blood vessel density. We conclude that VEGFR2 is consistently expressed in small artery myocytes of older people and may mediate effects of VEGF on brain vascular aging.
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Mani VE, Chauhan PS, Kalita J, Bhoi SK, Misra UK. Is VEGF a marker of severity of scrub typhus infection? Eur J Clin Microbiol Infect Dis 2016; 35:305-10. [PMID: 26718940 DOI: 10.1007/s10096-015-2546-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 12/07/2015] [Indexed: 01/19/2023]
Abstract
Vascular endothelial growth factor (VEGF) and its receptors have been reported as severity markers of septicemia. Scrub typhus (ST) results in multi-organ dysfunction but the role of VEGF has not been evaluated. We report VEGF and its receptors in ST and its correlation with severity, outcome and laboratory findings. Thirty patients with ST diagnosed by solid phase immune chromatographic assay and Weil-Felix tests were included. Their clinical details, Glasgow Coma Scale (GCS), SOFA and modified Rankin Scale (mRS) scores and laboratory findings were noted. VEGF, VEGFR1 and VEGFR2 were done by ELISA at admission and repeated at 1 month. Outcome was defined at 1 month. Serum VEGF and VEGF-R1 levels were significantly higher and VEGFR2 was significantly lower in the ST patients compared to the controls. These levels significantly improved at 1 month. VEGF level correlated with SOFA score (p = 0.05) and SGPT (p = 0.04). VEGFR1 correlated with hemoglobin (p = 0.04), platelet count (p = 0.03), serum CK (p = 0.001), weakness (p = 0.04) and mRS score (p = 0.04). VEGFR2 did not correlate with any clinical or laboratory parameters. All the patients recovered with doxycycline. Serum VEGF and VEGFR1 levels increased in ST and suggest disease severity but do not predict outcome.
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Affiliation(s)
- V E Mani
- Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareily Road, Lucknow, 226014, India
| | - P S Chauhan
- Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareily Road, Lucknow, 226014, India
| | - J Kalita
- Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareily Road, Lucknow, 226014, India.
| | - S K Bhoi
- Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareily Road, Lucknow, 226014, India
| | - U K Misra
- Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raebareily Road, Lucknow, 226014, India
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Deroost K, Pham TT, Opdenakker G, Van den Steen PE. The immunological balance between host and parasite in malaria. FEMS Microbiol Rev 2015; 40:208-57. [PMID: 26657789 DOI: 10.1093/femsre/fuv046] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2015] [Indexed: 12/16/2022] Open
Abstract
Coevolution of humans and malaria parasites has generated an intricate balance between the immune system of the host and virulence factors of the parasite, equilibrating maximal parasite transmission with limited host damage. Focusing on the blood stage of the disease, we discuss how the balance between anti-parasite immunity versus immunomodulatory and evasion mechanisms of the parasite may result in parasite clearance or chronic infection without major symptoms, whereas imbalances characterized by excessive parasite growth, exaggerated immune reactions or a combination of both cause severe pathology and death, which is detrimental for both parasite and host. A thorough understanding of the immunological balance of malaria and its relation to other physiological balances in the body is of crucial importance for developing effective interventions to reduce malaria-related morbidity and to diminish fatal outcomes due to severe complications. Therefore, we discuss in this review the detailed mechanisms of anti-malarial immunity, parasite virulence factors including immune evasion mechanisms and pathogenesis. Furthermore, we propose a comprehensive classification of malaria complications according to the different types of imbalances.
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Affiliation(s)
- Katrien Deroost
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium The Francis Crick Institute, Mill Hill Laboratory, London, NW71AA, UK
| | - Thao-Thy Pham
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Ghislain Opdenakker
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
| | - Philippe E Van den Steen
- Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven - University of Leuven, 3000 Leuven, Belgium
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Jain V, Basak S, Bhandari S, Bharti PK, Thomas T, Singh MP, Singh N. Burden of complicated malaria in a densely forested Bastar region of Chhattisgarh State (Central India). PLoS One 2014; 9:e115266. [PMID: 25531373 PMCID: PMC4274025 DOI: 10.1371/journal.pone.0115266] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Accepted: 11/20/2014] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND A prospective study on severe and complicated malaria was undertaken in the tribal dominated area of Bastar division, Chhattisgarh (CG), Central India, with an objective to understand the clinical epidemiology of complicated malaria in patients attending at a referral hospital. METHODS Blood smears, collected from the general medicine and pediatric wards of a government tertiary health care facility located in Jagdalpur, CG, were microscopically examined for malaria parasite from July 2010 to December 2013. The Plasmodium falciparum positive malaria cases who met enrollment criteria and provided written informed consent were enrolled under different malaria categories following WHO guidelines. PCR was performed to reconfirm the presence of P.falciparum mono infection among enrolled cases. Univariate and multivariate logistic regression analysis was done to identify different risk factors using STATA 11.0. RESULTS A total of 40,924 cases were screened for malaria. The prevalence of malaria and P.falciparum associated complicated malaria (severe and cerebral both) in the hospital was 6% and 0.81%, respectively. P.falciparum malaria prevalence, severity and associated mortality in this region peaked at the age of > 4-5 years and declined with increasing age. P.falciparum malaria was significantly more prevalent in children than adults (P < 0.00001). Among adults, males had significantly more P.falciparum malaria than females (P < 0.00001). Case fatality rate due to cerebral malaria and severe malaria was, respectively, 32% and 9% among PCR confirmed mono P.falciparum cases. Coma was the only independent predictor of mortality in multivariate regression analysis. Mortality was significantly associated with multi-organ complication score (P = 0.0003). CONCLUSION This study has revealed that the pattern of morbidity and mortality in this part of India is very different from earlier reported studies from India. We find that the peak morbidity and mortality in younger children regardless of seasonality. This suggests that this age group needs special care for control and clinical management.
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Affiliation(s)
- Vidhan Jain
- Regional Medical Research Centre for Tribals (RMRCT), ICMR, Garha, Jabalpur, Madhya Pradesh, India
| | - Sanjay Basak
- District Malaria Office, Maharani Hospital and associated Medical College Jagdalpur, Chhattisgarh, India
| | - Sneha Bhandari
- Regional Medical Research Centre for Tribals (RMRCT), ICMR, Garha, Jabalpur, Madhya Pradesh, India
| | - Praveen K. Bharti
- Regional Medical Research Centre for Tribals (RMRCT), ICMR, Garha, Jabalpur, Madhya Pradesh, India
| | - Trilok Thomas
- Regional Medical Research Centre for Tribals (RMRCT), ICMR, Garha, Jabalpur, Madhya Pradesh, India
| | - Mrigendra P. Singh
- National Institute of Malaria Research, Field Unit, Jabalpur, Madhya Pradesh, India
| | - Neeru Singh
- Regional Medical Research Centre for Tribals (RMRCT), ICMR, Garha, Jabalpur, Madhya Pradesh, India
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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.
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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
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Hempel C, Hoyer N, Staalsø T, Kurtzhals JA. Effects of the vascular endothelial growth factor receptor-2 (VEGFR-2) inhibitor SU5416 on in vitro cultures of Plasmodium falciparum. Malar J 2014; 13:201. [PMID: 24885283 PMCID: PMC4046387 DOI: 10.1186/1475-2875-13-201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 05/20/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Vascular endothelial growth factor (VEGF) is taken up by parasitized red blood cells during malaria and stimulates intra-erythrocytic growth of Plasmodium falciparum in vitro. The cause and consequence of this uptake is not understood. METHODS Plasmodium falciparum was cultured in vitro. Parasite growth and intracellular VEGF levels were assessed using flow cytometry. Intracellular VEGF was visualized by fluorescence immunocytochemistry. Phosphorylated tyrosine was measured by western blotting. In vivo assessment of intra-erythrocytic VEGF was performed in Plasmodium berghei ANKA-infected C57BL/6 mice. RESULTS VEGF accumulated intracellularly in infected red blood cells, particularly in schizonts. In vitro growth of P. falciparum was unchanged when co-cultured with the anti-VEGF antibody bevacizumab or with an anti-VEGF receptor-1 peptide. In contrast, the VEGF receptor-2 inhibitor, SU5416, dose-dependently inhibited growth. None of the treatments reduced intracellular VEGF levels. Thus, the anti-parasitic effect of SU5416 seemed independent of VEGF uptake. SU5416 reduced phosphorylated tyrosine in parasitized red blood cells. Similarly, the broad-spectrum tyrosine kinase inhibitor genistein dose-dependently inhibited P. falciparum growth and reduced tyrosine phosphorylation. Neither bevacizumab nor anti-VEGF receptor-1 peptide affected tyrosine kinase activity. Finally, in vivo uptake of VEGF in P. berghei ANKA was demonstrated, analogous to the in vitro uptake in P. falciparum, making it a possible model for the effects of VEGF signalling in vivo during malaria. CONCLUSIONS Inhibition of VEGFR-2 signalling reduces intra-erythrocytic growth of P. falciparum, likely due to tyrosine kinase inhibition. Internalisation of VEGF in P. falciparum-infected red blood cells does not rely on VEGF receptors. The function of in vivo uptake of VEGF can be studied in rodent malaria models.
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Affiliation(s)
| | - Nils Hoyer
- Centre for Medical Parasitology, Department of Clinical Microbiology, Copenhagen University Hospital, Copenhagen, Denmark.
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Canavese M, Spaccapelo R. Protective or pathogenic effects of vascular endothelial growth factor (VEGF) as potential biomarker in cerebral malaria. Pathog Glob Health 2014; 108:67-75. [PMID: 24601908 DOI: 10.1179/2047773214y.0000000130] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Cerebral malaria (CM) is the major lethal complication of Plasmodium falciparum infection. It is characterized by persistent coma along with symmetrical motor signs. Several clinical, histopathological, and laboratory studies have suggested that cytoadherence of parasitized erythrocytes, neural injury by malarial toxin, and excessive inflammatory cytokine production are possible pathogenic mechanisms. Although the detailed pathophysiology of CM remains unsolved, it is thought that the binding of parasitized erythrocytes to the cerebral endothelia of microvessels, leading to their occlusion and the consequent angiogenic dysregulation play a key role in the disease pathogenesis. Recent evidences showed that vascular endothelial growth factor (VEGF) and its receptor-related molecules are over-expressed in the brain tissues of CM patients, as well as increased levels of VEGF are detectable in biologic samples from malaria patients. Whether the modulation of VEGF is causative agent of CM mortality or a specific phenotype of patients with susceptibility to fatal CM needs further evaluation. Currently, there is no biological test available to confirm the diagnosis of CM and its complications. It is hoped that development of biomarkers to identify patients and potential risk for adverse outcomes would greatly enhance better intervention and clinical management to improve the outcomes. We review and discuss here what it is currently known in regard to the role of VEGF in CM as well as VEGF as a potential biomarker.
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11
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Prapansilp P, Medana I, Mai NTH, Day NPJ, Phu NH, Yeo TW, Hien TT, White NJ, Anstey NM, Turner GDH. A clinicopathological correlation of the expression of the angiopoietin-Tie-2 receptor pathway in the brain of adults with Plasmodium falciparum malaria. Malar J 2013; 12:50. [PMID: 23383853 PMCID: PMC3570345 DOI: 10.1186/1475-2875-12-50] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 01/14/2013] [Indexed: 02/08/2023] Open
Abstract
Background Plasma angiopoietin (Ang)-2 is associated with disease severity and mortality in adults and children with falciparum malaria. However the mechanism of action of the angiopoietins in fatal malaria is unclear. This study aimed to determine whether the expression of Ang-1 and Ang-2 and their receptor Tie-2 in cerebral endothelial or parenchymal cells was specific to cerebral malaria (CM), correlated with coma or other severe clinical features, and whether plasma and CSF levels of these markers correlated with the clinical and neuropathological features of severe and fatal malaria in Vietnamese adults. Methods Immunohistochemistry was performed for Ang-1, Ang-2 and Tie-2 on post-mortem brain tissue from fatal malaria cases and controls. Quantitative ELISA for plasma and cerebrospinal fluid levels of Ang-1, Ang-2 and Tie-2 was done to compare fatal cases with surviving patients from the same study. Results Immunohistochemistry revealed significant differences in expression in endothelial and parenchymal cells compared to controls. However there was no significant difference in expression of these markers on endothelial cells, astroglial cells or neurons between CM and non-cerebral malaria cases. Immunostaining of Ang-1, Ang-2 and Tie-2 was also not associated with Plasmodium falciparum-infected erythrocyte sequestration in the brain. However Ang-1 and Ang-2 expression in neurons was significantly correlated with the incidence of microscopic haemorrhages. Plasma levels of Ang-2 and Ang-2/Ang-1 ratio were associated with the number of severe malaria complications and were significant and independent predictors of metabolic acidosis and fatal outcome. Conclusions The independent prognostic significance of Ang-2 and the Ang-2/Ang-1 ratio in severe malaria was confirmed, although immunohistochemistry in fatal cases did not reveal increased expression on brain endothelium in cerebral versus non-cerebral cases. Activation of the Ang-Tie-2 pathway in severe malaria is therefore related to acidosis, number of severity criteria and outcome, but is not a specific event in the brain during cerebral malaria.
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Jain V, Lucchi NW, Wilson NO, Blackstock AJ, Nagpal AC, Joel PK, Singh MP, Udhayakumar V, Stiles JK, Singh N. Plasma levels of angiopoietin-1 and -2 predict cerebral malaria outcome in Central India. Malar J 2011; 10:383. [PMID: 22192385 PMCID: PMC3286486 DOI: 10.1186/1475-2875-10-383] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 12/23/2011] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND The mechanisms underlying the pathogenesis of cerebral malaria (CM) syndrome are not well understood. Previous studies have shown a strong association of inflammatory chemokines, apoptotic markers and angiogenic molecules with CM associated mortality. Recognizing the importance of angiopoietins (ANG) in the pathogenesis of CM, a retrospective investigation was carried out in a hospital cohort of malaria patients with Plasmodium infection in central India to determine if these factors could be suitable markers of CM associated severity. METHODS Patients enrolled in the study were clinically characterized as healthy controls (HC), mild malaria (MM), CM survivors (CMS) and CM non-survivors (CMNS) based on their malaria status and hospital treatment outcome. Plasma ANG-1 and ANG-2 levels were assessed using sandwich ELISA. Receiver operating characteristic (ROC) curve analysis was used to calculate area under the curve (AUC) for each biomarker in order to assess predictive accuracy of individual biomarkers. RESULTS The plasma levels of ANG-1 were lower in CMS and CMNS compared to control groups (mild malaria and healthy controls) at the time of hospital admission. On the contrary, ANG-2 levels positively correlated with malaria severity and were significantly higher in CMNS. The ratio of ANG-2/ANG-1 was highest in CMNS compared to other groups. Receiver operating characteristic curves revealed that compared to ANG-1 (AUC = 0.35), ANG-2 (AUC = 0.95) and ratio of ANG-2/ANG-1 (AUC = 0.90) were better markers to discriminate CMNS from MM cases. However, they were less specific in predicting fatal outcome amongst CM cases at the time of hospital admission. CONCLUSION These results suggest that at the time of admission plasma levels of ANG-2 and ratio of ANG-2/ANG-1 are clinically informative biomarkers to predict fatal CM from MM cases while they have limited usefulness in discriminating fatal CM outcomes in a pool of CM cases in endemic settings of Central India.
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Affiliation(s)
- Vidhan Jain
- Regional Medical Research Center for Tribals (ICMR), Nagpur Road, Garha, 482003 Jabalpur, Madhya Pradesh, India
| | - Naomi W Lucchi
- Atlanta Research and Education foundation Decatur, GA, USA
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Nana O Wilson
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Anna J Blackstock
- Atlanta Research and Education foundation Decatur, GA, USA
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Avinash C Nagpal
- Nethaji Subhash Chandra Bose Medical College Hospital, Jabalpur, Madhya Pradesh, India
| | - Pradeep K Joel
- Nethaji Subhash Chandra Bose Medical College Hospital, Jabalpur, Madhya Pradesh, India
| | - Mrigendra P Singh
- National Institute of Malaria Research Field Unit (ICMR), Jabalpur, Madhya Pradesh, India
| | - Venkatachalam Udhayakumar
- Atlanta Research and Education foundation Decatur, GA, USA
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention (CDC), Atlanta, GA, USA
| | - Jonathan K Stiles
- Department of Microbiology, Biochemistry and Immunology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Neeru Singh
- Regional Medical Research Center for Tribals (ICMR), Nagpur Road, Garha, 482003 Jabalpur, Madhya Pradesh, India
- National Institute of Malaria Research Field Unit (ICMR), Jabalpur, Madhya Pradesh, India
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13
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Medana IM, Day NPJ, Sachanonta N, Mai NTH, Dondorp AM, Pongponratn E, Hien TT, White NJ, Turner GDH. Coma in fatal adult human malaria is not caused by cerebral oedema. Malar J 2011; 10:267. [PMID: 21923924 PMCID: PMC3182981 DOI: 10.1186/1475-2875-10-267] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 09/17/2011] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND The role of brain oedema in the pathophysiology of cerebral malaria is controversial. Coma associated with severe Plasmodium falciparum malaria is multifactorial, but associated with histological evidence of parasitized erythrocyte sequestration and resultant microvascular congestion in cerebral vessels. To determine whether these changes cause breakdown of the blood-brain barrier and resultant perivascular or parenchymal cerebral oedema, histology, immunohistochemistry and image analysis were used to define the prevalence of histological patterns of oedema and the expression of specific molecular pathways involved in water balance in the brain in adults with fatal falciparum malaria. METHODS The brains of 20 adult Vietnamese patients who died of severe malaria were examined for evidence of disrupted vascular integrity. Immunohistochemistry and image analysis was performed on brainstem sections for activation of the vascular endothelial growth factor (VEGF) receptor 2 and expression of the aquaporin 4 (AQP4) water channel protein. Fibrinogen immunostaining was assessed as evidence of blood-brain barrier leakage and perivascular oedema formation. Correlations were performed with clinical, biochemical and neuropathological parameters of severe malaria infection. RESULTS The presence of oedema, plasma protein leakage and evidence of VEGF signalling were heterogeneous in fatal falciparum malaria and did not correlate with pre-mortem coma. Differences in vascular integrity were observed between brain regions with the greatest prevalence of disruption in the brainstem, compared to the cortex or midbrain. There was a statistically non-significant trend towards higher AQP4 staining in the brainstem of cases that presented with coma (P = .02). CONCLUSIONS Histological evidence of cerebral oedema or immunohistochemical evidence of localised loss of vascular integrity did not correlate with the occurrence of pre-mortem coma in adults with fatal falciparum malaria. Enhanced expression of AQP4 water channels in the brainstem may, therefore, reflect a mix of both neuropathological or attempted neuroprotective responses to oedema formation.
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Affiliation(s)
- Isabelle M Medana
- Nuffield Department of Clinical Laboratory Sciences, The John Radcliffe Hospital, University of Oxford, Oxford, UK
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14
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Hempel C, Combes V, Hunt NH, Kurtzhals JAL, Grau GER. CNS hypoxia is more pronounced in murine cerebral than noncerebral malaria and is reversed by erythropoietin. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:1939-50. [PMID: 21854739 DOI: 10.1016/j.ajpath.2011.06.027] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 05/18/2011] [Accepted: 06/28/2011] [Indexed: 01/13/2023]
Abstract
Cerebral malaria (CM) is associated with high mortality and risk of sequelae, and development of adjunct therapies is hampered by limited knowledge of its pathogenesis. To assess the role of cerebral hypoxia, we used two experimental models of CM, Plasmodium berghei ANKA in CBA and C57BL/6 mice, and two models of malaria without neurologic signs, P. berghei K173 in CBA mice and P. berghei ANKA in BALB/c mice. Hypoxia was demonstrated in brain sections using intravenous pimonidazole and staining with hypoxia-inducible factor-1α-specific antibody. Cytopathic hypoxia was studied using poly (ADP-ribose) polymerase-1 (PARP-1) gene knockout mice. The effect of erythropoietin, an oxygen-sensitive cytokine that mediates protection against CM, on cerebral hypoxia was studied in C57BL/6 mice. Numerous hypoxic foci of neurons and glial cells were observed in mice with CM. Substantially fewer and smaller foci were observed in mice without CM, and hypoxia seemed to be confined to neuronal cell somas. PARP-1-deficient mice were not protected against CM, which argues against a role for cytopathic hypoxia. Erythropoietin therapy reversed the development of CM and substantially reduced the degree of neural hypoxia. These findings demonstrate cerebral hypoxia in malaria, strongly associated with cerebral dysfunction and a possible target for adjunctive therapy.
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Affiliation(s)
- Casper Hempel
- Centre for Medical Parasitology, Department of Clinical Microbiology, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark.
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