| 1. |
- Pettersson, Fredrik, et al.
(författare)
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Whole-body imaging of sequestration of Plasmodium falciparum in the rat.
- 2005
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Ingår i: Infect Immun. - 0019-9567. ; 73:11, s. 7736-46
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Tidskriftsartikel (refereegranskat)abstract
- The occlusion of vessels by packed Plasmodium falciparum-infected (iRBC) and uninfected erythrocytes is a characteristic postmortem finding in the microvasculature of patients with severe malaria. Here we have employed immunocompetent Sprague-Dawley rats to establish sequestration in vivo. Human iRBC cultivated in vitro and purified in a single step over a magnet were labeled with 99mtechnetium, injected into the tail vein of the rat, and monitored dynamically for adhesion in the microvasculature using whole-body imaging or imaging of the lungs subsequent to surgical removal. iRBC of different lines and clones sequester avidly in vivo while uninfected erythrocytes did not. Histological examination revealed that a multiadhesive parasite adhered in the larger microvasculature, inducing extensive intravascular changes while CD36- and chondroitin sulfate A-specific parasites predominantly sequester in capillaries, inducing no or minor pathology. Removal of the adhesive ligand Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1), preincubation of the iRBC with sera to PfEMP1 or preincubation with soluble PfEMP1-receptors prior to injection significantly reduced the sequestration. The specificity of iRBC binding to the heterologous murine receptors was confirmed in vitro, using primary rat lung endothelial cells and rat lung cryosections. In offering flow dynamics, nonmanipulated endothelial cells, and an intact immune system, we believe this syngeneic animal model to be an important complement to existing in vitro systems for the screening of vaccines and adjunct therapies aiming at the prevention and treatment of severe malaria.
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| 2. |
- Reuterswärd, Philippa, et al.
(författare)
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Levels of human proteins in plasma as indicators for acute severe pediatric malaria
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundExisting low resource diagnostics for malaria infection suffer from sensitivity and specificity issues while lacking sufficient prognostic value. Identifying human host proteins could improve the possibilities to predict the risk of development of acute severe malaria. This will possible enable improved treatment and thereby lead to a decrease in mortality of malaria infected children. Furthermore, discovering host proteins with altered levels during active infection could generate leads to better understand host-parasite interaction.ResultsHere, we have analyzed a total of 541 pediatric plasma samples that were collected from community controls and individuals with mild or severe malaria in Rwanda. Protein profiles of these plasma samples were generated with an antibody-based suspension bead array containing 255 antibodies targeting 115 human proteins. We present 22 proteins with a strong discriminatory capacity (adjusted p-values below 10-19) for separating malaria cases from community controls. This panel of proteins contains among others acute phase proteins and proteins connected to cell adhesion and migration. Among these, three proteins showed lower plasma levels in the group of malaria-infected individuals compared to the control group. One of these proteins is the anti-adhesive secreted protein acidic and cysteine rich (SPARC) with possible connections to parasite cytoadhesion. A multi-protein panel of six proteins, including SPARC, could differentiate between controls and malaria cases with an AUC of 0.98. Furthermore, a panel of 37 proteins, including proteins associated to erythrocyte membranes, was identified as candidates for separation of mild and severe malaria patients (adjusted pvalues below 0.05).ConclusionThe herein identified set of human proteins has a significant discriminatory capacity between community controls and malaria cases. We also present proteins offering the possibility to enable stratification and risk prediction for the development of severe malaria. This constitutes an important set that could enable enhanced understanding and thereby also possibilities for better treatment of acute severe pediatric malaria.
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| 3. |
- Reuterswärd, Philippa, et al.
(författare)
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Levels of human proteins in plasma associated with acute paediatric malaria
- 2018
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Ingår i: Malaria Journal. - : BMC. - 1475-2875 .- 1475-2875. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- Background: The intimate interaction between the pathophysiology of the human host and the biology of the Plasmodium falciparum parasite results in a wide spectrum of disease outcomes in malaria. Development of severe disease is associated with a progressively augmented imbalance in pro- and anti-inflammatory responses to high parasite loads and sequestration of parasitized erythrocytes. Although these phenomena collectively constitute common denominators for the wide variety of discrete severe malaria manifestations, the mechanistic rationales behind discrepancies in outcome are poorly understood. Exploration of the human pathophysiological response by variations in protein profiles in plasma presents an excellent opportunity to increase the understanding. This is ultimately required for better prediction, prevention and treatment of malaria, which is essential for ongoing elimination and eradication efforts. Results: An affinity proteomics approach was used to analyse 541 paediatric plasma samples collected from community controls and patients with mild or severe malaria in Rwanda. Protein profiles were generated with an antibody-based suspension bead array containing 255 antibodies targetting 115 human proteins. Here, 57 proteins were identified with significantly altered levels (adjusted p-values<0.001) in patients with malaria compared to controls. From these, the 27 most significant proteins (adjusted p-values<10(-14)) were selected for a stringent analysis approach. Here, 24 proteins showed elevated levels in malaria patients and included proteins involved in acute inflammatory response as well as cell adhesion. The remaining three proteins, also implicated in immune regulation and cellular adhesivity, displayed lower abundance in malaria patients. In addition, 37 proteins (adjusted p-values<0.05) were identified with increased levels in patients with severe compared to mild malaria. This set includes, proteins involved in tissue remodelling and erythrocyte membrane proteins. Collectively, this approach has been successfully used to identify proteins both with known and unknown association with different stages of malaria. Conclusion: In this study, a high-throughput affinity proteomics approach was used to find protein profiles in plasma linked to P. falciparum infection and malaria disease progression. The proteins presented herein are mainly involved in inflammatory response, cellular adhesion and as constituents of erythrocyte membrane. These findings have a great potential to provide increased conceptual understanding of host-parasite interaction and malaria pathogenesis.
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