Malaria in Pregnancy Interacts with and Alters the Angiogenic Profiles of the Placenta

Histomorphometric features of placentae from women having malaria and HIV coinfection with preterm births

Background

Malaria and HIV are associated with preterm births possibly due to partial maternal vascular malperfusion resulting from altered placental angiogenesis. There is a paucity of data describing structural changes associated with malaria and HIV coinfection in the placentae of preterm births thus limiting the understanding of biological mechanisms by which preterm birth occurs.

Objectives

This study aimed to determine the differences in clinical characteristics, placental parenchymal histological, and morphometric features of the terminal villous tree among women with malaria and HIV coinfection having preterm births.

Methods

Twenty-five placentae of preterm births with malaria and HIV coinfection (cases) were randomly selected and compared to twenty-five of those without both infections (controls). Light microscopy was used to determine histological features on H&E and MT-stained sections while histomorphometric features of the terminal villous were analyzed using image analysis software. Clinical data regarding maternal age, parity, marital status, level of education, gestational age and placental weight were compared.

Results

Placental weight, villous perimeter and area were significantly lower in cases as compared to controls 454g vs. 488g, 119.32μm vs. 130.47μm, and 937.93μm2 vs. 1132.88μm2 respectively. Increased syncytial knots and accelerated villous maturity were significantly increased in the cases. The relative risk of development of partial maternal vascular malperfusion was 2.1 (CI: 1.26-3.49).

Conclusion

These findings suggest that malaria and HIV coinfection leads to partial maternal vascular malperfusion that may lead to chronic hypoxia in the placenta and altered weight, villous perimeter and surface area. This may represent a mechanism by which malaria and HIV infection results in pre-term births.

Complement System Activation Is a Plasma Biomarker Signature during Malaria in Pregnancy

Malaria in pregnancy (MiP) is a public health problem in malaria-endemic areas, contributing to detrimental outcomes for both mother and fetus. Primigravida and second-time mothers are most affected by severe anemia complications and babies with low birth weight compared to multigravida women. Infected erythrocytes (IE) reach the placenta, activating the immune response by placental monocyte infiltration and inflammation. However, specific markers of MiP result in poor outcomes, such as low birth weight, and intrauterine growth restriction for babies and maternal anemia in women infected with Plasmodium falciparum are limited. In this study, we identified the plasma proteome signature of a mouse model infected with Plasmodium berghei ANKA and pregnant women infected with Plasmodium falciparum infection using quantitative mass spectrometry-based proteomics. A total of 279 and 249 proteins were quantified in murine and human plasma samples, of which 28% and 30% were regulated proteins, respectively. Most of the regulated proteins in both organisms are involved in complement system activation during malaria in pregnancy. CBA anaphylatoxin assay confirmed the complement system activation by the increase in C3a and C4a anaphylatoxins in the infected plasma compared to non-infected plasma. Moreover, correlation analysis showed the association between complement system activation and reduced head circumference in newborns from Pf-infected mothers. The data obtained in this study highlight the correlation between the complement system and immune and newborn outcomes resulting from malaria in pregnancy.

Fetal Growth Retardation is Associated with High Apoptotic Cells and Low VEGF Expression in Placenta of Malarial Pregnant Mice

Background

During pregnancy, pregnant women are susceptible to malaria, contributing significantly to maternal and infant mortality.

Objective

This research was conducted to study the effect of Plasmodium berghei infection in pregnant mice on fetal growth retardation through placental cell apoptosis and the change of local vascularization.

Methods

Eighteen pregnant Balb/c strain mice resulting from simultanously mating were divided into two groups those were nine pregnant mice used as non infected group and nine pregnant mice infected with Plasmodium berghei on day 9th post mating used as infected group respectively. On day 15th of post mating, all of the pregnant mice were killed. Fetal weights were measured using analytic balance. Apoptosis of placental cells and VEGF expression in the placental tissue were measured using immunohistochemistry.

Results

Result showed that there was sequestration of parasite-infected red blood cells (PRBCs) in intervillous space. Statistical analysis showed that the fetal weights in infected pregnant mice group was significantly lower than non infected one (p = 0.01), and the placental cell apoptosis in placental tissue of infected pregnant mice was significantly higher than the non infected one (p=0.00).There was also a significant difference on VEGF expression between infected group and non infected group (p= 0,00).

Conclusion

Plasmodium berghei infection in pregnant Balb/c mice can cause fetal growth retardation due to high of placental cell apoptosis and low VEGF expression.

The Angiopoietin-Tie2 axis contributes to placental vascular disruption and adverse birth outcomes in malaria in pregnancy

Background

Malaria during pregnancy is a major contributor to the global burden of adverse birth outcomes including fetal growth restriction, preterm birth, and fetal loss. Recent evidence supports a role for angiogenic dysregulation and perturbations to placental vascular development in the pathobiology of malaria in pregnancy. The Angiopoietin-Tie2 axis is critical for placental vascularization and remodeling. We hypothesized that disruption of this pathway would contribute to malaria-induced adverse birth outcomes.

Methods

Using samples from a previously conducted prospective cohort study of pregnant women in Malawi, we measured circulating levels of angiopoietin-1 (Angpt-1) and Angpt-2 by Luminex (n=1392). We used a preclinical model of malaria in pregnancy (Plasmodium berghei ANKA [PbA] in pregnant BALB/c mice), genetic disruption of Angpt-1 (Angpt1^+/− mice), and micro-CT analysis of placental vasculature to test the hypothesis that disruptions to the Angpt-Tie2 axis by malaria during pregnancy would result in aberrant placental vasculature and adverse birth outcomes.

Findings

Decreased circulating levels of Angpt-1 and an increased ratio of Angpt-2/Angpt-1 across pregnancy were associated with malaria in pregnancy. In the preclinical model, PbA infection recapitulated disruptions to the Angiopoietin-Tie2 axis resulting in reduced fetal growth and viability. Malaria decreased placental Angpt-1 and Tie2 expression and acted synergistically with reduced Angpt-1 in heterozygous dams (Angpt1^+/−), to worsen birth outcomes by impeding vascular remodeling required for placental function.

Interpretation

Collectively, these data support a mechanistic role for the Angpt-Tie2 axis in malaria in pregnancy, including a potential protective role for Angpt-1 in mitigating infection-associated adverse birth outcomes.

Funding

This work was supported by the Canadian Institutes of Health Research (CIHR), Canada Research Chair, and Toronto General Research Institute Postdoctoral Fellowship Award. The parent trial was supported by the European & Developing Countries Clinical Trials Partnership and the Malaria in Pregnancy Consortium, which was funded by the Bill & Melinda Gates Foundation. The funders had no role in design, analysis, or reporting of these studies.

TLR4-Endothelin Axis Controls Syncytiotrophoblast Motility and Confers Fetal Protection in Placental Malaria

Pregnancy-associated malaria is often associated with adverse pregnancy outcomes. Placental circulatory impairments are an intriguing and unsolved component of malaria pathophysiology. Here, we uncovered a Toll-like receptor 4 (TLR4)-TRIF-endothelin axis that controls trophoblast motility and is linked to fetal protection during Plasmodium infection. In a cohort of 401 pregnancies from northern Brazil, we found that infection during pregnancy reduced expression of endothelin receptor B in syncytiotrophoblasts, while endothelin expression was only affected during acute infection. We further show that quantitative expression of placental endothelin and endothelin receptor B proteins are differentially controlled by maternal and fetal TLR4 alleles. Using murine malaria models, we identified placental autonomous responses to malaria infection mediated by fetally encoded TLR4 that not only controlled placental endothelin gene expression but also correlated with fetal viability protection. In vitro assays showed that control of endothelin expression in fetal syncytiotrophoblasts exposed to Plasmodium-infected erythrocytes was dependent on TLR4 via the TRIF pathway but not MyD88 signaling. Time-lapse microscopy in syncytiotrophoblast primary cultures and cell invasion assays demonstrated that ablation of TLR4 or endothelin receptor blockade abrogates trophoblast collective motility and cell migration responses to infected erythrocytes. These results cohesively substantiate the hypothesis that fetal innate immune sensing, namely, the TRL4-TRIF pathway, exerts a fetal protective role during malaria infection by mediating syncytiotrophoblast vasoregulatory responses that counteract placental insufficiency.

Adverse pregnancy outcomes are associated with Plasmodium vivax malaria in a prospective cohort of women from the Brazilian Amazon

BACKGROUND

Malaria in Brazil represents one of the highest percentages of Latin America cases, where approximately 84% of infections are attributed to Plasmodium (P.) vivax. Despite the high incidence, many aspects of gestational malaria resulting from P. vivax infections remain poorly studied. As such, we aimed to evaluate the consequences of P. vivax infections during gestation on the health of mothers and their neonates in an endemic area of the Amazon.

METHODS AND FINDINGS

We have conducted an observational cohort study in Brazilian Amazon between January 2013 and April 2015. 600 pregnant women were enrolled and followed until delivery. After applying exclusion criteria, 329 mother-child pairs were included in the analysis. Clinical data regarding maternal infection, newborn's anthropometric measures, placental histopathological characteristics, and angiogenic and inflammatory factors were evaluated. The presence of plasma IgG against the P. vivax (Pv) MSP119 protein was used as marker of exposure and possible associations with pregnancy outcomes were analyzed. Multivariate logistic regression analysis revealed that P. vivax infections during the first trimester of pregnancy are associated with adverse gestational outcomes such as premature birth (adjusted odds ratio [aOR] 8.12, 95% confidence interval [95%CI] 2.69-24.54, p < 0.0001) and reduced head circumference (aOR 3.58, 95%CI 1.29-9.97, p = 0.01). Histopathology analysis showed marked differences between placentas from P. vivax-infected and non-infected pregnant women, especially regarding placental monocytes infiltrate. Placental levels of vasomodulatory factors such as angiopoietin-2 (ANG-2) and complement proteins such as C5a were also altered at delivery. Plasma levels of anti-PvMSP119 IgG in infected pregnant women were shown to be a reliable exposure marker; yet, with no association with improved pregnancy outcomes.

CONCLUSIONS

This study indicates that P. vivax malaria during the first trimester of pregnancy represents a higher likelihood of subsequent poor pregnancy outcomes associated with marked placental histologic modification and angiogenic/inflammatory imbalance. Additionally, our findings support the idea that antibodies against PvMSP119 are not protective against poor pregnancy outcomes induced by P. vivax infections.

Poor Birth Outcomes in Malaria in Pregnancy: Recent Insights Into Mechanisms and Prevention Approaches

Pregnant women in malaria-endemic regions are susceptible to malaria in pregnancy, which has adverse consequences on birth outcomes, including having small for gestational age and preterm babies. These babies are likely to have low birthweights, which predisposes to infant mortality and lifelong morbidities. During malaria in pregnancy, Plasmodium falciparum-infected erythrocytes express a unique variant surface antigen, VAR2CSA, that mediates sequestration in the placenta. This process may initiate a range of host responses that contribute to placental inflammation and dysregulated placental development, which affects placental vasculogenesis, angiogenesis and nutrient transport. Collectively, these result in the impairment of placental functions, affecting fetal development. In this review, we provide an overview of malaria in pregnancy and the different pathological pathways leading to malaria in pregnancy-associated low birthweight. We also discuss current prevention and management strategies for malaria in pregnancy, and some potential therapeutic interventions that may improve birth outcomes. Lastly, we outline some priorities for future research that could bring us one step closer to reducing this health burden.

Reduced birth weight caused by sextuple drug resistant Plasmodium falciparum infection in early 2nd trimester

Mutations in the Plasmodium falciparum genes Pfdhfr and Pfdhps, particularly the sextuple mutant haplotype threatens the antimalarial effectiveness of sulfadoxine-pyrimethamine as intermittent preventive treatment during pregnancy (IPTp). To explore the impact of sextuple mutant haplotype infections on outcome measures after provision of IPTp-SP, we monitored birth outcomes in women followed from prior to conception or from the first trimester until delivery. Women infected with sextuple haplotypes in early 2 nd trimester specifically, delivered newborns with a lower birth weight (-267g, 95% CI -454; -59, p=0·01) compared to women who did not have malaria during pregnancy and women infected with less SP resistant haplotypes (-461g, 95% CI -877; -44, p=0·03). Thus, sextuple haplotype infections seems to impact the effectiveness of SP for IPTp and directly impact birth outcome by lowering birth weight. Close monitoring and targeted malaria control during early pregnancy is therefore crucial to improve birth outcomes.

Malaria in Early Pregnancy and the Development of the Placental Vasculature

BACKGROUND

Pregnancy malaria has a negative impact on fetal outcome. It is uncertain whether infections in early pregnancy have a clinical impact by impeding the development of the placental vasculature.

METHODS

Tanzanian women (n = 138) were closely monitored during pregnancy. Placentas collected at birth were investigated using stereology to establish the characteristics of placental villi and vessels. Placental vasculature measures were compared between women infected with malaria and controls.

RESULTS

Compared with controls, placentas from women infected with malaria before a gestational age (GA) of 15 weeks had a decreased volume of transport villi (mean decrease [standard deviation], 12.45 [5.39] cm3; P = .02), an increased diffusion distance in diffusion vessels (mean increase, 3.33 [1.27] µm; P = .01), and a compensatory increase in diffusion vessel surface area (mean increase, 1.81 [0.74 m2]; P = .02). In women who had malaria before a GA of 15 weeks diffusion vessel surface area and transport vessel length distance were positive predictors for birth weight (multilinear regression: P = .007 and P = .055 for diffusion surface area and transport length, respectively) and GA at delivery (P = .005 and P = .04).

CONCLUSIONS

Malaria infection in early pregnancy impedes placental vascular development. The resulting phenotypic changes, which can be detected at delivery, are associated with birth weight and gestational length.

CLINICAL TRIALS REGISTRATION

NCT02191683.

Biosensors for Detection of Human Placental Pathologies: A Review of Emerging Technologies and Current Trends

Substantial growth in the biosensor research has enabled novel, sensitive and point-of-care diagnosis of human diseases in the last decade. This paper presents an overview of the research in the field of biosensors that can potentially predict and diagnosis of common placental pathologies. A survey of biomarkers in maternal circulation and their characterization methods is presented, including markers of oxidative stress, angiogenic factors, placental debris, and inflammatory biomarkers that are associated with various pathophysiological processes in the context of pregnancy complications. Novel biosensors enabled by microfluidics technology and nanomaterials is then reviewed. Representative designs of plasmonic and electrochemical biosensors for highly sensitive and multiplexed detection of biomarkers, as well as on-chip sample preparation and sensing for automatic biomarker detection are illustrated. New trends in organ-on-a-chip based placental disease models are highlighted to illustrate the capability of these in vitro disease models in better understanding the complex pathophysiological processes, including mass transfer across the placental barrier, oxidative stress, inflammation, and malaria infection. Biosensor technologies that can be potentially embedded in the placental models for real time, label-free monitoring of these processes and events are suggested. Merger of cell culture in microfluidics and biosensing can provide significant potential for new developments in advanced placental models, and tools for diagnosis, drug screening and efficacy testing.

The Impact of Infection in Pregnancy on Placental Vascular Development and Adverse Birth Outcomes

Healthy fetal development is dependent on nutrient and oxygen transfer via the placenta. Optimal growth and function of placental vasculature is therefore essential to support in utero development. Vasculogenesis, the de novo formation of blood vessels, and angiogenesis, the branching and remodeling of existing vasculature, mediate the development and maturation of placental villi, which form the materno-fetal interface. Several lines of evidence indicate that systemic maternal infection and consequent inflammation can disrupt placental vasculogenesis and angiogenesis. The resulting alterations in placental hemodynamics impact fetal growth and contribute to poor birth outcomes including preterm delivery, small-for-gestational age (SGA), stillbirth, and low birth weight (LBW). Furthermore, pathways involved in maternal immune activation and placental vascularization parallel those involved in normal fetal development, notably neurovascular development. Therefore, immune-mediated disruption of angiogenic pathways at the materno-fetal interface may also have long-term neurological consequences for offspring. Here, we review current literature evaluating the influence of maternal infection and immune activation at the materno-fetal interface and the subsequent impact on placental vascular function and birth outcome. Immunomodulatory pathways, including chemokines and cytokines released in response to maternal infection, interact closely with the principal pathways regulating placental vascular development, including the angiopoietin-Tie-2, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) pathways. A detailed mechanistic understanding of how maternal infections impact placental and fetal development is critical to the design of effective interventions to promote placental growth and function and thereby reduce adverse birth outcomes.

Maternal-Fetal Conflict During Infection: Lessons From a Mouse Model of Placental Malaria

Infections that reach the placenta via maternal blood can target the fetal-placental barrier and are associated with reduced birth weight, increased stillbirth, miscarriage and perinatal mortality. Malaria during pregnancy can lead to infection of the placental tissue and to adverse effects on the unborn child even if the parasite is successfully cleared, indicating that placental sufficiency is significantly compromised. Human samples and animal models of placental malaria have been used to unravel mechanisms contributing to this insufficiency and have implicated molecular pathways related to inflammation, innate immunity and nutrient transport. Remarkably, fetal TLR4 was found to take part in placental responses that protect the fetus, in contrast to maternal TLR4 responses that presumably preserve the mother‘s health but result in reduced fetal viability. We propose that this conflict of fetal and maternal responses is a determinant of the clinical outcomes of placental malaria and that fetally derived trophoblasts are on the front lines of this conflict.

Impact of HIV-1 infection on the IGF-1 axis and angiogenic factors in pregnant Cameroonian women receiving antiretroviral therapy

Although mother-to-child transmission of HIV has dramatically declined, the number of in utero HIV-exposed, uninfected infants is on the increase. HIV-exposed infants are at an increased risk of mortality, morbidity and slower early growth than their non-HIV exposed counterparts. Maternal HIV increases the risk of having preterm deliveries, intrauterine growth restriction and low birth weight babies. However, the mechanism underlying dysregulation of fetal growth in HIV-infected pregnant women is unknown. We sought to determine whether maternal HIV is associated with dysregulation of the insulin-like growth factor (IGF) axis, some angiogenic factors or other related biomarkers that regulate fetal growth. A total of 102 normotensive pregnant women were enrolled in a small cross-sectional study. Amongst these were thirty-one HIV-1 positive women receiving combination antiretroviral therapy (cART) (Mean age: 30.0 ± 5.1 years; % on ART: 83.9%; median plasma viral load: 683 copies/ml; median CD4 count: 350 cells/ul) and 71 HIV uninfected women (mean age: 27.3 ± 5.8) recruited at delivery. A panel of biomarkers including IGF1 and IGF binding proteins (IGFBP1, IGFBP3), angiopoietins (ANG) 1 and 2, matrix metalloproteinases (MMP) 2 and 9, and galectin 13, was measured in plasma collected from the placental intervillous space. The levels of IGF1, IGFBP1, ANG1, ANG2, MMP2, MMP9 and Gal-13 were not affected by maternal HIV, even when adjusted for maternal factors in linear regression models (all p>0.05). It was observed that HIV-infection in pregnancy did not significantly affect key markers of the IGF axis and angiogenic factors. If anything, it did not affect women. These findings highlight the importance of the use of ART during pregnancy, which maintains factors necessary for fetal development closer to those of healthy women. However, decrease in IGF1 levels might be exacerbated in women con-infected with HIV and malaria.

Induction of Angiogenesis by Malarial Infection through Hypoxia Dependent Manner

Malarial infection induces tissue hypoxia in the host through destruction of red blood cells. Tissue hypoxia in malarial infection may increase the activity of HIF1α through an intracellular oxygen-sensing pathway. Activation of HIF1α may also induce vascular endothelial growth factor (VEGF) to trigger angiogenesis. To investigate whether malarial infection actually generates hypoxia-induced angiogenesis, we analyzed severity of hypoxia, the expression of hypoxia-related angiogenic factors, and numbers of blood vessels in various tissues infected with Plasmodium berghei. Infection in mice was performed by intraperitoneal injection of 2×106 parasitized red blood cells. After infection, we studied parasitemia and survival. We analyzed hypoxia, numbers of blood vessels, and expression of hypoxia-related angiogenic factors including VEGF and HIF1α. We used Western blot, immunofluorescence, and immunohistochemistry to analyze various tissues from Plasmodium berghei-infected mice. In malaria-infected mice, parasitemia was increased over the duration of infection and directly associated with mortality rate. Expression of VEGF and HIF1α increased with the parasitemia in various tissues. Additionally, numbers of blood vessels significantly increased in each tissue type of the malaria-infected group compared to the uninfected control group. These results suggest that malarial infection in mice activates hypoxia-induced angiogenesis by stimulation of HIF1α and VEGF in various tissues.

Molecular Principles of Intrauterine Growth Restriction in Plasmodium Falciparum Infection

Malaria in pregnancy still constitutes a particular medical challenge in tropical and subtropical regions. Of the five Plasmodium species that are pathogenic to humans, infection with Plasmodium falciparum leads to fulminant progression of the disease with massive impact on pregnancy. Severe anemia of the mother, miscarriage, stillbirth, preterm delivery and intrauterine growth restriction (IUGR) with reduced birth weight are frequent complications that lead to more than 10,000 maternal and 200,000 perinatal deaths annually in sub-Saharan Africa alone. P. falciparum can adhere to the placenta via the expression of the surface antigen VAR2CSA, which leads to sequestration of infected erythrocytes in the intervillous space. This process induces a placental inflammation with involvement of immune cells and humoral factors. Especially, monocytes get activated and change the release of soluble mediators, including a variety of cytokines. This proinflammatory environment contributes to disorders of angiogenesis, blood flow, autophagy, and nutrient transport in the placenta and erythropoiesis. Collectively, they impair placental functions and, consequently, fetal growth. The discovery that women in endemic regions develop a certain immunity against VAR2CSA-expressing parasites with increasing number of pregnancies has redefined the understanding of malaria in pregnancy and offers strategies for the development of vaccines. The following review gives an overview of molecular processes in P. falciparum infection in pregnancy which may be involved in the development of IUGR.

Bradykinin Sequestration by Plasmodium berghei Infected Erythrocytes Conditions B2R Signaling and Parasite Uptake by Fetal Trophoblasts

Plasmodium infection during pregnancy causes placental malfunction reducing fetus sustainability and leading to abortions, stillbirths, low birth weight or premature delivery. Accumulation of infected erythrocytes (IE) in the placenta is a key factor in placental malaria pathogenesis but the role played by fetal trophoblast that contact maternal blood has been neglected. Here we explore the hypothesis that interactions between Plasmodium-IE and fetal trophoblast cells impact on vasoactive alterations underlying placental dysfunction. We screened gene expression of key mediators in vasoactive pathways. We found that mRNA of bradykinin receptor 2 (B2R) and nitric oxide synthase (eNOS), as well as levels of bradykinin (BK), were decreased in late gestation placentas of pregnant Plasmodium berghei-infected mice. Co-culturing mouse trophoblasts with IE down-regulated B2R transcription and interleukin (IL)-6 secretion in a B2R-signaling dependent manner. IE showed increased levels of surface B2R and enhanced capacity to bind BK. We propose that down-regulation of B2R signaling in the course of IE–trophoblast interactions is due to BK sequestration by IE. In corroboration, levels of BK were lower in infected placentas and the positive correlation of B2R gene expression and fetal weight was disrupted by infection. This indicates that deregulation of the BK-B2R pathway is associated to placental dysfunction provoked by malaria infection. We further found that upon inhibition of B2R signaling, trophoblasts engulf IE to a lesser extent and show reduced production of IL-6. Our data suggest that BK sequestration by P. berghei represents a strategy for the parasite to ameliorate the risk of phagocytic capture by down modulating B2R activation.

Interferon-γ and Interleukin-10 Responses during Clinical Malaria Episodes in Infants Aged 0-2 Years Prenatally Exposed to Plasmodium falciparum: Tanzanian Birth Cohort

Background

Infants born to mothers with placental malaria are prenatally exposed to Plasmodium falciparum antigens. However, the effect of that exposure to subsequent immune responses has not been fully elucidated. This study aimed at determining the effect of prenatal exposure to P. falciparum on Interleukin-10 and Interferon-γ responses during clinical malaria episodes in the first 24 months of life.

Methods

This prospective cohort study involved 215 infants aged 0-2 years born to mothers with or without placental malaria. Enzyme-linked immunosorbent assay (ELISA) was used to determine levels of IL-10 and IFN-γ in infants and detect IgM in cord blood. Data were analyzed using SPSS version 20.

Findings

Geometric mean for IFN-γ in exposed infants was 557.9 pg/ml (95% CI: 511.6-604.1) and in unexposed infants it was 634.4 pg/ml (95% CI: 618.2-668.5) (P=0.02). Mean IL-10 was 22.4 pg/ml (95% CI: 19.4-28.4) and 15.1 pg/ml (95%CI: 12.4-17.6), respectively (P=0.01).

Conclusions

Prenatal exposure to P. falciparum antigens significantly affects IL-10 and IFN-γ responses during clinical malaria episodes in the first two years of life.

Endothelial Activation: The Ang/Tie Axis in Sepsis

Sepsis, a dysregulated host response to infection that causes life-threatening organ dysfunction, is a highly heterogeneous syndrome with no specific treatment. Although sepsis can be caused by a wide variety of pathogenic organisms, endothelial dysfunction leading to vascular leak is a common mechanism of injury that contributes to the morbidity and mortality associated with the syndrome. Perturbations to the angiopoietin (Ang)/Tie2 axis cause endothelial cell activation and contribute to the pathogenesis of sepsis. In this review, we summarize how the Ang/Tie2 pathway is implicated in sepsis and describe its prognostic as well as therapeutic utility in life-threatening infections.

Severe malaria: what's new on the pathogenesis front?

Plasmodium falciparum causes the most severe and fatal form of malaria in humans with over half a million deaths each year. Cerebral malaria, a complex neurological syndrome of severe falciparum malaria, is often fatal and represents a major public health burden. Despite vigorous efforts, the pathophysiology of cerebral malaria remains to be elucidated, thereby hindering the development of adjunctive therapies. In recent years, multidisciplinary and collaborative approaches have led to groundbreaking progress both in the laboratory and in the field. Here we review the latest breakthroughs in severe malaria pathogenesis, with a specific focus on new pathogenetic mechanisms leading to cerebral malaria. The most recent findings point towards specific parasite phenotypes targeting brain microvasculature, endothelial dysfunction and subsequent oedema-induced brain swelling.

Prevalence of low birth weight, macrosomia and stillbirth and their relationship to associated maternal risk factors in Hohoe Municipality, Ghana

INTRODUCTION

birth weight is vital to the development potential of the newborn. Abnormal birth weight (such as low birth weight and macrosomia) is an important determinant of child survival, disabilities, stunting, and long-term adverse consequences for the onset of non-communicable diseases in the life course and therefore demands appropriate public health interventions. Stillbirths are also considered one of the most important, but most poorly understood and documented adverse outcomes of pregnancy. Therefore, this study aimed to assess the prevalence of abnormal birth weight and related maternal risk factors, as well as pregnancy outcomes, such as stillbirth.

METHODS

a retrospective study design was used to analyze 4262 delivery records for singleton pregnancies from January 2013 to December 2014 seen at the Hohoe municipal hospital, Volta region in Ghana. The data on birth weight and related factors were derived from the delivery book. Data was analyzed using STATA. Multinomial logistic regression was used to assess the association between maternal factors such as parity, age and intermittent preventive treatment of malaria, sex of infant and abnormal birth weight. Association between stillbirth and related factors was assessed using logistic regression.

RESULTS

prevalence of low birth weight (<2.5kg) was 9.69% and macrosomia (≥4.0kg) was 3.03%. There was an increased risk of a first born being of low birth weight than second or third born (RR; 2.04, CI; 1.59-2.64, p<0.0001). There were also an increased risks of mothers <20 years giving birth to low-birthweight infants (RR; 1.46, CI; 1.11-1.93, p=0.007) compared to mothers who were within the age ranges of 20-30 years and also among those who took only one (RR; 1.57, CI; 1.02-2.39, p=0.039) or no intermittent preventive treatment for malaria during pregnancy (RR; 1.57, CI; 1.24-1.98, p=<0.0001) compared to those who took three doses. Risk of macrosomic birth was particularly high among 5th born (RR; 2.66, CI; 1.43-4.95, p=0.002) compared to first or second born. Stillbirth rate was 27/1000 births. Thirty-two percent of the stillbirths (n=38) had low birth weight whereas 6.8% (n=8) were macrosomic. There was a greater than fivefold (AOR; 5.6, CI; 3.6-8.7) and greater than twofold (AOR; 2.4, CI; 1.1-5.3, p=0.025) increase in odds for stillbirth among low birth weight and macrosomic infants respectively.

CONCLUSION

macrosomia and low birth weight co-existed among infants in Hohoe municipality, both of which are associated with adverse pregnancy outcome such as stillbirth. Given the apparent association between maternal age <20 years and increased risk, health promotion strategies aimed at preventing pregnancies among teenagers could be implemented to aid the reduction of stillbirth rates.

Abundance of megalin and Dab2 is reduced in syncytiotrophoblast during placental malaria, which may contribute to low birth weight

Placental malaria caused by Plasmodium falciparum contributes to ~200,000 child deaths annually, mainly due to low birth weight (LBW). Parasitized erythrocyte sequestration and consequent inflammation in the placenta are common attributes of placental malaria. The precise molecular details of placental changes leading to LBW are still poorly understood. We hypothesized that placental malaria may disturb maternofetal exchange of vitamins, lipids, and hormones mediated by the multi-ligand (n ~ 50) scavenging/signaling receptor megalin, which is abundantly expressed in placenta but was not previously analyzed in pregnancy outcomes. We studied abundance of megalin and its intracellular adaptor protein Dab2 by immunofluorescence microscopy in placental biopsies from Ugandan women with (n = 8) and without (n = 20) active placental malaria. We found that: (a) abundances of both megalin (p = 0.01) and Dab2 (p = 0.006) were significantly reduced in brush border of syncytiotrophoblast of infected placentas; (b) amounts of megalin and Dab2 were strongly correlated (Spearman's r = 0.53, p = 0.003); (c) abundances of megalin and Dab2 (p = 0.046) were reduced in infected placentas from women with LBW deliveries. This study provides first evidence that placental malaria infection is associated with reduced abundance of megalin transport/signaling system and indicate that these changes may contribute to the pathology of LBW.

Impact of Malaria in Pregnancy as Latin America Approaches Elimination

In Latin America, four million pregnancies are at risk of malaria annually, but malaria in pregnancy is largely overlooked. As countries progress toward malaria elimination, targeting reservoirs of transmission is a priority. Pregnant women are an important risk group because they harbor asymptomatic infections and dormant liver stages of Plasmodium vivax that cause relapses. Of significant concern is the discovery that most infections in pregnant women fail to be detected by routine diagnostics. We review here recent findings on malaria in pregnancy within Latin America. We focus on the Amazon basin and Northwest Colombia, areas that harbor the greatest burden of malaria, and propose that more sensitive diagnostics and active surveillance at antenatal clinics will be necessary to eliminate malaria from these final frontiers.