scholarly journals Reduced CD36-dependent tissue sequestration of Plasmodium-infected erythrocytes is detrimental to malaria parasite growth in vivo

2011 ◽  
Vol 209 (1) ◽  
pp. 93-107 ◽  
Author(s):  
Jannik Fonager ◽  
Erica M. Pasini ◽  
Joanna A.M. Braks ◽  
Onny Klop ◽  
Jai Ramesar ◽  
...  

Adherence of parasite-infected red blood cells (irbc) to the vascular endothelium of organs plays a key role in the pathogenesis of Plasmodium falciparum malaria. The prevailing hypothesis of why irbc adhere and sequester in tissues is that this acts as a mechanism of avoiding spleen-mediated clearance. Irbc of the rodent parasite Plasmodium berghei ANKA sequester in a fashion analogous to P. falciparum by adhering to the host receptor CD36. To experimentally determine the significance of sequestration for parasite growth, we generated a mutant P. berghei ANKA parasite with a reduced CD36-mediated adherence. Although the cognate parasite ligand binding to CD36 is unknown, we show that nonsequestering parasites have reduced growth and we provide evidence that in addition to avoiding spleen removal, other factors related to CD36-mediated sequestration are beneficial for parasite growth. These results reveal for the first time the importance of sequestration to a malaria infection, with implications for the development of strategies aimed at reducing pathology by inhibiting tissue sequestration.

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Rosangela Frita ◽  
Daniel Carapau ◽  
Maria M. Mota ◽  
Thomas Hänscheid

Hemozoin (Hz) is released into the blood stream after rupture of infected red blood cells (iRBCs) at the end of each parasite replication cycle. This free Hz is ingested by circulating and resident phagocytes. The presence of Hz in tissues after clearance of infection has been previously reported. Still, little is known about the kinetics of Hz in vivo, during and after Plasmodium infection. It is particularly important to understand Hz kinetics after malaria infections as it has been reported that Hz is associated with impairment of immune functions, including possible consequences for coinfections. Indeed, if Hz remains biologically active for prolonged periods of time inside immunocompetent cells, the potential consequences of such accumulation and presence to the immune system should be clarified. Here, using several independent methods to assess the presence of Hz, we report the long-term in vivo kinetics of Hz in diverse organs in a murine model of malaria infection.


Author(s):  
Kartika Arum Wardani ◽  
Kholida Nur Aini ◽  
Heny Arwati ◽  
Willy Sandhika

Abstract Sequestration of Plasmodium berghei ANKA-infected erythrocytes occurs in BALB/c mice as characteristic of  Plasmodium falciparum infection in humans. Animals’ bile has been widely used for centuries in Traditional Chinese Medicine. Goat bile has been used in healing infectious and non-infectious diseases; however, no report on the use of goat bile against malaria infection and sequestration. The purpose of this study was to analyze the correlation between parasitemia and sequestration in the liver of P.berghei ANKA-infected BALB/c mice treated with goat bile. This research was an in vivo experimental study using the post-test control group design. The male BALB/c mice aged ± 6 weeks, body weight 20-25 g were used. The mice were divided into five groups where Group 1-3 were mice treated with goat bile 25%, 50%, and 100%, respectively. Group 4-5 were negative (sterile water) and positive controls (DHP). Parasitemia was observed daily from each mouse and the number of sequestered infected erythrocytes on the endothelium of sinusoids. The data were analyzed using t independent test. Antimalarial activity of goat bile was shown by the lower parasitemia in goat bile-treated mice compared with the negative control. The average number of sequestration was goat bile concentration-dependent manner. The higher the concentration, the lower the number of sequestration. Sequestration was correlated with parasitemia (p=0,0001). Sequestration of P.berghei ANKA-infected erythrocytes correlated with parasitemia, and was goat bile concentration-dependent manner. Keywords: Malaria, parasitemia, sequestration, goat bileCorrespondence: [email protected]


Author(s):  
Udeme O. Georgewill ◽  
Festus Azibanigha Joseph ◽  
Elias Adikwu

Nitrofurantoin (NT) used for the treatment of urinary tract infections may have antiplasmodial activity. Dihydroartemisinin-piperaquine (DP) is an artemisinin based combination therapy used for the treatment of malaria. This study evaluated the antiplasmodial effect of dihydroartemisinin-piperaquine-nitrofurantoin (DP-NT) on mice infected with Plasmodium berghei. Adult Swiss albino mice (30-35 g) of both sexes were used. The mice were randomly grouped, inoculated with Plasmodium berghei, and treated orally with DP (1.7/13.7 mg/kg), NT (57.1 mg/kg) and DP-NT (1.71/13.7/ 57.1 mg/kg), respectively using curative, prophylactic and suppressive tests. The negative control was orally treated with normal saline (0.3 mL), while the positive control was orally treated with chloroquine CQ (10mg/kg). After treatment, blood samples were collected and evaluated for percentage parasitemia, inhibitions and hematological parameters. Liver samples were evaluated for histological changes. The mice were observed for mean survival time (MST). Treatment with DP-NT decreased parasitemia levels when compared to individual doses of DP and NT with significant difference observed at p<0.05. DP-NT prolonged MST when compared to individual doses of DP and NT with significant difference observed at p<0.05. The decrease in packed cell volume, red blood cells, hemoglobin and increase in white blood cells in parasitized mice were significantly restored by DP-NT  when compared to individual doses of DP and NT with difference observed at p<0.05. DP-NT eradicated liver Plasmodium parasite.  NT remarkably increased the antiplasmodial activity of DP. DP-NT may be used for the treatment of malaria.


2019 ◽  
Author(s):  
Francisco Cai ◽  
Tiffany M. DeSimone ◽  
Elsa Hansen ◽  
Cameron V. Jennings ◽  
Amy K. Bei ◽  
...  

AbstractThe growth of the malaria parasitePlasmodium falciparumin human blood causes all clinical manifestations of malaria, a process that begins with the invasion of red blood cells. Parasites enter red blood cells using distinct pairs of parasite ligands and host receptors that define particular invasion pathways. Parasite strains have the capacity to switch between invasion pathways. This flexibility is thought to facilitate immune evasion against particular parasite ligands, but may also reflect the fact that red blood cell surfaces are dynamic and composed of heterogeneous invasion targets. Different host genetic backgrounds affecting red blood cell structure have long been recognized to impact parasite growthin vivo, but even within a host, red blood cells undergo dramatic changes in morphology and receptor density as they age. The consequences of these heterogeneities for parasite growthin vivoremain unclear. Here, we measured the ability of laboratory strains ofP. falciparumrelying on distinct invasion pathways to enter red blood cells of different ages. We estimated invasion efficiency while accounting for the fact that even if the red blood cells display the appropriate receptors, not all are physically accessible to invading parasites. This approach revealed a tradeoff made by parasites between the fraction of susceptible cells and their invasion rate into them. We were able to distinguish between “specialist” strains exhibiting high invasion rate in fewer cells versus “generalist” strains invading less efficiently into a larger fraction of cells. We developed a mathematical model to predict that infection with a generalist strain would lead to higher peak parasitemiasin vivowhen compared with a specialist strain with similar overall proliferation rate. Thus, the heterogeneous ecology of red blood cells may play a key role in determining the rate of parasite proliferation between different strains ofP. falciparum.


1999 ◽  
Vol 190 (11) ◽  
pp. 1711-1716 ◽  
Author(s):  
Masao Yuda ◽  
Hiroshi Sakaida ◽  
Yasuo Chinzei

CTRP (circumsporozoite protein and thrombospondin-related adhesive protein [TRAP]-related protein) of the rodent malaria parasite Plasmodium berghei (PbCTRP) makes up a protein family together with other apicomplexan proteins that are specifically expressed in the host-invasive stage 1. PbCTRP is produced in the mosquito-invasive, or ookinete, stage and is a protein candidate for a role in ookinete adhesion and invasion of the mosquito midgut epithelium. To demonstrate involvement of PbCTRP in the infection of the vector, we performed targeting disruption experiments with this gene. PbCTRP disruptants showed normal exflagellation rates and development into ookinetes. However, no oocyst formation was observed in the midgut after ingestion of these parasites, suggesting complete loss of their invasion ability. On the other hand, when ingested together with wild-type parasites, disruptants were able to infect mosquitoes, indicating that the PbCTRP gene of the wild-type parasite rescued infectivity of disruptants when they heterologously mated in the mosquito midgut lumen. Our results show that PbCTRP plays a crucial role in malaria infection of the mosquito midgut and suggest that similar molecular mechanisms are used by malaria parasites to invade cells in the insect vector and the mammalian host.


2019 ◽  
Vol 234 (11) ◽  
pp. 20546-20553 ◽  
Author(s):  
Sangwoo Kwon ◽  
Dong‐Hun Lee ◽  
Se‐Jik Han ◽  
Woochul Yang ◽  
Fu‐Shi Quan ◽  
...  

Parasitology ◽  
2016 ◽  
Vol 143 (12) ◽  
pp. 1672-1680 ◽  
Author(s):  
YAN DING ◽  
WENYUE XU ◽  
TAOLI ZHOU ◽  
TAIPING LIU ◽  
HONG ZHENG ◽  
...  

SUMMARYMalaria remains one of the most devastating diseases. Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection resulting in high mortality and morbidity worldwide. Analysis of precise mechanisms of CM in humans is difficult for ethical reasons and animal models of CM have been employed to study malaria pathogenesis. Here, we describe a new experimental cerebral malaria (ECM) model with Plasmodium berghei ANKA infection in KunMing (KM) mice. KM mice developed ECM after blood-stage or sporozoites infection, and the development of ECM in KM mice has a dose-dependent relationship with sporozoites inoculums. Histopathological findings revealed important features associated with ECM, including accumulation of mononuclear cells and red blood cells in brain microvascular, and brain parenchymal haemorrhages. Blood–brain barrier (BBB) examination showed that BBB disruption was present in infected KM mice when displaying clinical signs of CM. In vivo bioluminescent imaging experiment indicated that parasitized red blood cells accumulated in most vital organs including heart, lung, spleen, kidney, liver and brain. The levels of inflammatory cytokines interferon-gamma, tumour necrosis factor-alpha, interleukin (IL)-17, IL-12, IL-6 and IL-10 were all remarkably increased in KM mice infected with P. berghei ANKA. This study indicates that P. berghei ANKA infection in KM mice can be used as ECM model to extend further research on genetic, pharmacological and vaccine studies of CM.


2015 ◽  
Vol 2015 ◽  
pp. 1-4 ◽  
Author(s):  
Peace Mayen Edwin Ubulom ◽  
Chinweizu Ejikeme Udobi ◽  
Mark Iheukwumere Madu

Objective. The study was designed to determine the efficacy of combined Amodiaquine and Ciprofloxacin in plasmodiasis therapy.Method. The in vivo antiplasmodial effect of different dosage levels of Amodiaquine, Ciprofloxacin, and their combinations againstPlasmodium berghei bergheiwas evaluated using Swiss albino mice.Results. Amodiaquine (a known antiplasmodial agent) had a fairly significant antiplasmodial effect reducing the parasites for every 100 red blood cells (RBC) from 66 to 16 (75.75%) at the tolerable dosage level of 7.5 mg/kg body weight while Ciprofloxacin (an antibiotic known to have antimalarial effect) showed an insignificant antiplasmodial effect reducing the parasites for every 100 RBC from 65 to 64 (1.53%) at the tolerable dosage level of 10.7 mg/kg body weight. Conversely, the combination therapy of Amodiaquine and Ciprofloxacin had a significant antiplasmodial effect at all the doses administered. The combination of 7.5 mg/kg of Amodiaquine and 12.8 mg/kg of Ciprofloxacin, however, showed the most significant antiplasmodial effect of the doses used reducing the number of parasites per 100 RBC from 60 to 10 (83.33%).Conclusions. Appropriate Amodiaquine and Ciprofloxacin combination will be effective for the treatment of malaria and better than either Amodiaquine or Ciprofloxacin singly at their recommended dosage levels.


2018 ◽  
Vol 3 ◽  
pp. 155 ◽  
Author(s):  
Melissa C. Kapulu ◽  
Patricia Njuguna ◽  
Mainga M. Hamaluba ◽  

Malaria remains a major public health burden despite approval for implementation of a partially effective pre-erythrocytic malaria vaccine. There is an urgent need to accelerate development of a more effective multi-stage vaccine. Adults in malaria endemic areas may have substantial immunity provided by responses to the blood stages of malaria parasites, but field trials conducted on several blood-stage vaccines have not shown high levels of efficacy.  We will use controlled human malaria infection (CHMI) studies with malaria-exposed volunteers to identify correlations between immune responses and parasite growth rates in vivo.  Immune responses more strongly associated with control of parasite growth should be prioritized to accelerate malaria vaccine development. We aim to recruit up to 200 healthy adult volunteers from areas of differing malaria transmission in Kenya, and after confirming their health status through clinical examination and routine haematology and biochemistry, we will comprehensively characterize immunity to malaria using >100 blood-stage antigens. We will administer 3,200 aseptic, purified, cryopreserved Plasmodium falciparum sporozoites (PfSPZ Challenge) by direct venous inoculation. Serial quantitative polymerase chain reaction to measure parasite growth rate in vivo will be undertaken. Clinical and laboratory monitoring will be undertaken to ensure volunteer safety. In addition, we will also explore the perceptions and experiences of volunteers and other stakeholders in participating in a malaria volunteer infection study. Serum, plasma, peripheral blood mononuclear cells and extracted DNA will be stored to allow a comprehensive assessment of adaptive and innate host immunity. We will use CHMI in semi-immune adult volunteers to relate parasite growth outcomes with antibody responses and other markers of host immunity. Registration: ClinicalTrials.gov identifier NCT02739763.


2021 ◽  
Vol 11 ◽  
Author(s):  
Yifan Zhao ◽  
Peng Sun ◽  
Yue Ma ◽  
Xiaoqiang Chang ◽  
Xingyu Chen ◽  
...  

Dihydroartemisinin (DHA) and its’ derivatives have been employed as the most powerful first-line drugs for malarial treatment for several decades. The metabolism of DHA has not been studied clearly. Previous reports were focused on the pharmacokinetics procedure of DHA in healthy rats. The metabolites of DHA in red blood cells (RBC), especially in the RBC from Plasmodium-infected models, have rarely been studied. The Plasmodium species parasitize inside RBC, and these cells should be the final place where DHA performs its activity. In this study, the profile of DHA metabolites in biosample (blood, plasma, and RBC) of the infected and healthy mice was investigated with UPLC-Q-TOF-MS and UNIFI platform to gain insight into DHA metabolism. Results show that a total of 25 metabolites were successfully identified in infected (30 in healthy) blood, 27 in infected (27 in healthy) plasma, and 15 in infected (22 in healthy) RBC. Results show that hydroxylation, OH-dehydration, and glucuronidation reactions were important in the metabolic pathway in vivo. Significantly, DHA metabolites inside RBC were identified for the first time. 8-Hydroxy (8-OH) DHA, 4α-OH deoxy ART, and 6β-OH deoxy ART were identified in vivo for the first time.


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