losartan-potassium and Parasitemia

The pathophysiology of malarial anemia is multifactorial and incompletely understood. We assessed mechanistic and risk factors for post-malarial anemia in Ghanaian and Gabonese children with severe P. falciparum malaria treated with parenteral artesunate followed by an oral artemisinin-combination therapy. We analyzed data from two independent studies in which children were followed on Days 7,14, and 28 after treatment with artesunate. Specific hematological parameters included the presence of hemoglobinopathies and erythropoietin. Presence of once-infected erythrocytes was assessed by flow cytometry in a sub-population. Of 143 children with a geometric mean parasitemia of 116,294/µL (95% CI: 95,574-141,505), 91 (88%) had anemia (Hb < 10 g/dL) at presentation. Hemoglobin increased after Day 7 correlating with increased erythropoiesis through adequate erythropoietin stimulation. 22 children (24%) remained anemic until Day 28. Post-artesunate delayed hemolysis was detected in 7 children (5%) with only minor differences in the dynamics of once-infected erythrocytes. Hyperparasitemia and hemoglobin at presentation were associated with anemia on Day 14. On Day 28 only lower hemoglobin at presentation was associated with anemia. Most children showed an adequate erythropoiesis and recovered from anemia within one month. Post-artesunate delayed hemolysis (PADH) and hyperparasitemia are associated with early malarial anemia and pre-existing anemia is the main determinant for prolonged anemia.

Topics: Anemia; Antimalarials; Artesunate; Blood Transfusion; Child; Child, Preschool; Erythropoietin; Female; Humans; Infant; Infusions, Parenteral; Malaria; Male; Parasitemia

Trypanosoma carassii is a flagellated bloodstream parasite of cyprinid fish with pathogenesis manifesting primarily as anemia in experimentally infected fish. This anemia is characterized by decreases in the number of circulating red blood cells (RBCs) during peak parasitemia. We examined changes in the key blood metrics and expression of genes known to be important in the regulation of erythropoiesis. Increasing parasitemia was strongly correlated with an overall decrease in the total number of circulating RBCs. Gene expression of key erythropoiesis regulators (EPO, EPOR, GATA1, Lmo2, and HIFα) and proinflammatory cytokines (IFNγ and TNFα) were measured and their expressions differed from those in fish made anemic by injections of phenylhydrazine (PHZ). Significant upregulation of pro-erythropoietic genes was observed in PHZ-induced anemia, but not during peak parasitic infection. Previously, we reported on functional characterization of goldfish erythropoietin (rgEPO) and its ability to induce survival and differentiation of erythroid progenitor cells in vitro. Treatment of goldfish during the infection with rgEPO reduced the severity of anemia but failed to fully prevent the onset of the anemic state in infected fish. Proinflammatory cytokines have been implicated in the suppression of erythropoiesis during trypanosomiasis, specifically the cytokines TNFα, IFNγ, and IL-1β. Analysis of key proinflammatory cytokines revealed that mRNA levels of IFNγ and TNFα were upregulated in response to infection, but only TNFα increased in response to PHZ treatment. Synergistic activity of the proinflammatory cytokines may be required to sustain prolonged anemia. These findings provide insight into the relationship between T. carassii and host anemia and suggest that T. carassii may directly or indirectly suppress host erythropoiesis.

Topics: Anemia; Animals; Cytokines; Erythrocyte Count; Erythropoiesis; Erythropoietin; GATA1 Transcription Factor; Gene Expression Regulation; Goldfish; Interferon-gamma; LIM Domain Proteins; Parasitemia; Phenylhydrazines; Receptors, Erythropoietin; RNA, Messenger; Trypanosoma; Trypanosomiasis; Tumor Necrosis Factor-alpha

Malaria infection leads to anemia in humans which generally occurs during the chronic phase of the infection. The role that erythropoietic molecules play for anemia during malaria at low parasitemia levels is still controversial due to the lack of suitable animal models which might mimic this condition. In this regard, α-tocopherol transfer protein knockout mice, with undetectable levels of vitamin E in circulation, were possibly used as a model to investigate the role that erythropoietic molecules such as erythropoietin (EPO), erythropoietin receptor (EPOR), and macrophage migration inhibitory factor (MIF) play on the outcome of anemia during uncomplicated malaria infection at low parasitemias. The results indicate that the degree of parasitemia unlikely plays any important effect on mRNA expression of EPO and EPOR in different organs. Moreover, even though EPO and EPOR productions are impaired in the kidney and bone marrow, respectively, other organs such as the liver and spleen intend to compensate production of these cytokines to prevent anemia in the infected animals.

Topics: Anemia; Animals; Carrier Proteins; Erythropoietin; Gene Knockout Techniques; Malaria; Mice; Mice, Inbred C57BL; Mice, Knockout; Parasitemia; Plasmodium berghei; Receptors, Erythropoietin

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.

Topics: Animals; Brain; Disease Models, Animal; Erythropoietin; Female; Fluorescent Dyes; Humans; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Malaria, Cerebral; Mice; Nitroimidazoles; Parasitemia; Plasmodium berghei; Poly(ADP-ribose) Polymerases; Survival Analysis; Treatment Outcome

Iron deficiency anemia (IDA) affects many young women in sub-Saharan Africa. Its etiology is multifactorial, but the major cause is low dietary iron bioavailability exacerbated by parasitic infections such as malaria.. We investigated whether asymptomatic Plasmodium falciparum parasitemia in Beninese women would impair absorption of dietary iron or utilization of circulating iron.. Iron absorption and utilization from an iron-fortified sorghum-based meal were estimated by using oral and intravenous isotope labels in 23 afebrile women with a positive malaria smear (asexual P. falciparum parasitemia; > 500 parasites/μL blood). The women were studied while infected, treated, and then restudied 10 d after treatment. Iron status, hepcidin, and inflammation indexes were measured before and after treatment.. Treatment reduced low-grade inflammation, as reflected by decreases in serum ferritin, C-reactive protein, interleukin-6, interleukin-8, and interleukin-10 (P < 0.05); this was accompanied by a reduction in median serum hepcidin of ≈ 50%, from 2.7 to 1.4 nmol/L (P < 0.005). Treatment decreased serum erythropoietin and growth differentiation factor 15 (P < 0.05). Clearance of parasitemia increased geometric mean dietary iron absorption (from 10.2% to 17.6%; P = 0.008) but did not affect systemic iron utilization (85.0% compared with 83.1%; NS).. Dietary iron absorption is reduced by ≈ 40% in asymptomatic P. falciparum parasitemia, likely because of low-grade inflammation and its modulation of circulating hepcidin. Because asymptomatic parasitemia has a protracted course and is very common in malarial areas, this effect may contribute to IDA and blunt the efficacy of iron supplementation and fortification programs. This trial was registered at clinicaltrials.gov as NCT01108939.

Topics: Adolescent; Adult; Anemia, Iron-Deficiency; Antimicrobial Cationic Peptides; Benin; Erythropoietin; Female; Ferritins; Food, Fortified; Growth Differentiation Factor 15; Hepcidins; Humans; Inflammation; Inflammation Mediators; Intestinal Absorption; Iron, Dietary; Isotope Labeling; Malaria, Falciparum; Parasitemia; Plasmodium falciparum; Sorghum; Young Adult

To gain insight into potential relationships between tumor necrosis factor alpha (TNF-alpha), interleukin 10 (IL-10), erythropoietin (EPO), and anemia in acute malaria, 90 children 3 to 11 years with acute malaria were studied. According to parasitemia and hemoglobin levels, they were divided into 3 groups: G1 (mild): asexual low-density Plasmodium falciparum parasitemia <8000 parasites/ul and hemoglobin levels >8g/dl. G2 (high-density uncomplicated): asexual high-density parasitemia (>8000 parasites/ul, with hemoglobin levels >8 g/dl. G3 (anemia): with severe malaria symptoms and parasitemia with anemia (hemoglobin levels <8 g/dl). Hospital controls included 10 children with matching age group who required inpatient management but had no malaria parasitemia. Good marrow response was in G1 & G2 showed by elevation of serum EPO and soluble transferring receptors (sTfR) and increased red cell distribution width (RDW). In G3, bone marrow suppression was in spite of increased EPO level in response to anemia. TNF-alpha level was significantly higher G2 and G3 (P.05). IL-10 levels in G1 were significantly higher than in hospital control group (P<0.05). The highest level of IL-10 was in G2. The mean IL-10 to TNF-alpha ratio in G2 (4.64) was significantly higher (P<.005) than in G3 (mean ratio, 1.77).

Topics: Anemia; Animals; Case-Control Studies; Child; Child, Preschool; Erythropoietin; Female; Hemoglobins; Humans; Interleukin-10; Malaria, Falciparum; Male; Parasitemia; Plasmodium falciparum; Saudi Arabia; Tumor Necrosis Factor-alpha

Cerebral involvement during malaria is a complication that leads to seizure, coma, and death. The effect of new neuroprotective therapies has not yet been investigated, although cerebral malaria shares some features with neurological stroke. Erythropoietin (EPO) is one of the more promising drugs in this area. We measured the effect of EPO on the survival of mice infected with Plasmodium berghei ANKA and demonstrated that inoculations of recombinant human EPO at the beginning of the clinical manifestations of cerebral malaria protect >90% of mice from death. This drug has no effect on the course of parasitemia. The effect of EPO was not related to either the inhibition of apoptosis in the brain or the regulation of the increase and decrease of nitric oxide production in the brain and blood, respectively. Tumor necrosis factor-alpha and interferon-gamma mRNA overexpression was inhibited by EPO, and treated mice had fewer brain hemorrhages. EPO has been used in patients with chronic diseases for years, and more recently it has been used to treat acute ischemic stroke. The data presented here provide the first evidence indicating that this cytokine could be useful for the symptomatic prevention of mortality during the acute stage of cerebral malaria.

Topics: Animals; Apoptosis; Brain; Disease Models, Animal; Erythropoietin; Female; Gene Expression; Interferon-gamma; Malaria; Malaria, Cerebral; Mice; Neuroprotective Agents; Nitric Oxide; Parasitemia; Plasmodium berghei; Recombinant Proteins; RNA, Messenger; Survival Analysis; Tumor Necrosis Factor-alpha

The effect of erythropoietin treatment on Trypanosoma congolense infection in mice was studied. Survival rates of mice were dramatically improved by treatment with recombinant human erythropoietin (r-hu-EPO; 5,000 U/kg) when infected with 1,000 cells of T. congolense IL3000 (P < 0.05). All the untreated mice infected with T. congolense IL3000 died by day 9 of infection; however, 100%, 50%, and 25% of the mice treated with r-hu-EPO for 8 days survived to day 20, day 40, and day 60 of the parasitical infection, respectively. Anti-8-hydroxy-2'-deoxyguanosine antibody, a biomarker for oxidative damage of DNA, yielded positive reactions in the cytoplasm of the parasites recovered from the mice treated with r-hu-EPO. These results, taken together, indicate that erythropoietin administration is effective for the treatment of T. congolense infection.

Topics: Anemia; Animals; Antibodies, Monoclonal; DNA Primers; DNA Probes; Erythropoietin; Female; Gene Expression Profiling; Hematocrit; Mice; Mice, Inbred C57BL; Parasitemia; Pentamidine; Polymerase Chain Reaction; Receptors, Erythropoietin; Recombinant Proteins; Survival Analysis; Time Factors; Trypanosoma congolense; Trypanosomiasis, African

Although maternal anaemia often stems from malaria infection during pregnancy, its effects on foetal haemoglobin levels are not straightforward. Lower-than-expected cord haemoglobin values in malarious versus non-malarious regions were noted by one review, which hypothesized they resulted from foetal immune activation to maternal malaria. This study addressed this idea by examining cord haemoglobin levels in relation to maternal malaria, anaemia, and markers of foetal immune activation.. Cord haemoglobin levels were examined in 32 malaria-infected and 58 uninfected women in Blantyre, Malawi, in relation to maternal haemoglobin levels, malaria status, and markers of foetal haematological status, hypoxia, and inflammation, including TNF-alpha, TGF-beta, and ferritin. All women were HIV-negative.. Although malaria was associated with a reduction in maternal haemoglobin (10.8 g/dL vs. 12.1 g/dL, p < 0.001), no reduction in cord haemoglobin and no significant relationship between maternal and cord haemoglobin levels were found. Cord blood markers of haematological and hypoxic statuses did not differ between malaria-infected and uninfected women. Maternal malaria was associated with decreased TGF-beta and increased cord ferritin, the latter of which was positively correlated with parasitaemia (r = 0.474, p = 0.009). Increased cord ferritin was associated with significantly decreased birth weight and gestational length, although maternal and cord haemoglobin levels and malaria status had no effect on birth outcome.. In this population, cord haemoglobin levels were protected from the effect of maternal malaria. However, decreased TGF-beta and elevated ferritin levels in cord blood suggest foetal immune activation to maternal malaria, which may help explain poor birth outcomes.

Topics: Adolescent; Adult; Cohort Studies; Erythropoietin; Female; Ferritins; Fetal Blood; Hemoglobins; Humans; Infant, Newborn; Malaria; Malawi; Parasitemia; Placenta Diseases; Pregnancy; Pregnancy Complications, Parasitic

Severe anaemia can develop in the aftermath of Plasmodium falciparum malaria because of protracted bone marrow suppression, possibly due to residual subpatent parasites.. Blood was collected from patients with recent malaria and negative malaria microscopy. Detection of the Plasmodium antigens, lactate dehydrogenase (Optimal), aldolase and histidine rich protein 2 (Now malaria) were used to differentiate between patients with (1) no malaria, (2) recent cleared malaria, (3) persistent P. falciparum infection. Red cell distribution width (RDW), plasma levels of soluble transferrin receptor (sTfR) and erythropoietin (EPO) were measured as markers of erythropoiesis. Interleukin (IL) 10 and tumour necrosis factor (TNF)alpha were used as inflammation markers.. EPO was correlated with haemoglobin, irrespective of malaria (R = -0.36, P < 0.001). Persistent P. falciparum infection, but not recent malaria without residual parasites, was associated with bone marrow suppression i.e., low RDW (P < 0.001 vs. P = 0.56) and sTfR (P = 0.02 vs. P = 0.36). TNF-alpha and IL-10 levels were not associated with bone marrow suppression.. In the treatment of malaria, complete eradication of parasites may prevent subsequent development of anaemia. Severely anaemic children may benefit from antimalarial treatment if antigen tests are positive, even when no parasites can be demonstrated by microscopy.

Topics: Anemia; Animals; Bone Marrow Diseases; Child; Child, Preschool; Erythropoiesis; Erythropoietin; Female; Hemoglobins; Humans; Infant; Interleukin-10; L-Lactate Dehydrogenase; Malaria, Falciparum; Male; Parasitemia; Proteins; Receptors, Transferrin; Tumor Necrosis Factor-alpha

Acute Trypanosoma congolense infection induced moderate, transient anemia in N'Dama cattle (trypanotolerant) and severe anemia in Boran cattle (trypanosusceptible). Erythropoietin receptor (EpoR) was cloned and sequenced from the two breeds of cattle. A single position mutation of Tyr in the Boran to His in the N'Dama predicted amino acid sequence was revealed. The mRNA transcription of erythropoietin (Epo) in kidneys and EpoR in the bone marrow of infected cattle was determined by competitive reverse transcription and the polymerase chain reaction (RT-PCR). Though Epo mRNA transcription increased in the kidneys during infection, the increase was not significantly different (p>0.05) between the two breeds of infected cattle. The level of EpoR transcripts in the bone marrow of infected N'Damas was significantly higher (p<0.05) than that detected in the marrows from infected Boran cattle. While infection seem to increase levels of transcription of IL-1alpha and beta, and TNFalpha in kidneys from both Boran and N'Dama cattle, no significant difference was detected in the level of mRNAs of these cytokines in the kidney from the two breed of cattle. The amount of IFNgamma mRNA transcripts were not changed with infection in N'Dama cattle, while on the contrary a significant higher levels of IFNgamma was found in kidneys from infected Boran cattle as compared to the other groups. A significant (p<0.05) increase in the levels of IL-1alpha and beta, and IFNgamma mRNA transcripts were detected in the marrows of infected Borans as compared to the infected N'Dama cattle. In this study the increase in the level of TNFalpha mRNA in the marrows of the two infected breeds was not different. This implies there is no negative effect of TNFalpha on hematopoiesis during acute infection. These findings suggest that the levels of Epo and EpoR in the infected Boran cattle were inadequate for their degree of anemia, which might be due in part to high expression of IFNgamma during acute infection with T. congolense.

Topics: Acute Disease; Amino Acid Sequence; Animals; Blood Cell Count; Bone Marrow; Cattle; Cell Count; DNA, Complementary; Erythropoietin; Female; Gene Expression; Interferon-gamma; Interleukin-1; Kidney; Male; Molecular Sequence Data; Parasitemia; Receptors, Erythropoietin; RNA, Messenger; Sequence Analysis, DNA; Trypanosoma congolense; Trypanosomiasis, African; Tumor Necrosis Factor-alpha

Plasma immunoreactive erythropoietin concentrations were determined in 84 children with Plasmodium falciparum malaria in Gabon. There was an inverse log/linear relationship between hemoglobin or hematocrit and plasma erythropoietin, indicating that erythropoietin levels increased exponentially as circulating hemoglobin decreased. These result show that P. falciparum malaria does not lead to decreased erythropoietin production, and in turn reduced erythropoietin production does not contribute to the pathogenesis of malarial anemia. There is an adequate response of erythropoietin to anemia in children with P. falciparum malaria.

Topics: Age Factors; Anemia; Blood Transfusion; Child; Child, Preschool; Erythropoietin; Female; Hematocrit; Hemoglobins; Humans; Infant; Malaria, Falciparum; Male; Parasitemia; Regression Analysis; Severity of Illness Index