Soluble fms-like tyrosine kinase-1 and soluble endoglin in HIV-associated preeclampsia

Literature Review: The sFlt1/PlGF Ratio and Pregestational Maternal Comorbidities: New Risk Factors to Predict Pre-Eclampsia

One of the main causes of maternal and neonatal morbidity and mortality is pre-eclampsia. It is characterized by a high sFlt1/PlGF ratio, according to prior research. Pregestational diseases in mothers may increase the risk of developing pre-eclampsia. Only a few studies have looked at the connection between maternal comorbidities before conception and the sFlt1/PlGF ratio. The most recent information regarding the association between maternal pregestational diseases and the ratio of sFlt1/PlGF is described in this review. The paper also examines current research suggesting that changes in pregnancy hormones and metabolites are related to a high sFlt1/PlGF ratio. Certain maternal disorders have been found to dramatically raise sFlt-1 and sFlt1/PlGF levels, according to an analysis of the literature. There is still debate about the data on the association between the sFlt1/PlGF ratio and maternal disorders such as HIV, acute coronary syndromes, cardiovascular function in the mother between 19 and 23 weeks of pregnancy, thyroid hormones, diabetes, and cancer. Additional research is needed to confirm these findings.

Protease inhibitor-based antiretroviral therapy in pregnancy: effects on hormones, placenta, and decidua

The use of antiretroviral therapy (ART) in pregnancy is important for maternal health, and has been successful in reducing vertical transmission rates to almost zero in those taking effective ART regimens with good adherence. However, there are reports of higher rates of low birthweight and preterm births in women with HIV, which can be further exacerbated by ART usage in pregnancy. Protease inhibitors, and ritonavir-boosted lopinavir in particular, might directly contribute to placental and uteroplacental pathology in part by altering plasma concentrations of the essential steroid hormones of pregnancy, progesterone and oestradiol. In this Review, we collate the increasing evidence of dysregulated maternal endocrinology, reproductive physiology, and placental compromise associated with protease inhibitors. Based on findings of placental and decidual effects, we recommend that ritonavir-boosted lopinavir should be avoided in pregnancy, in line with US and European guidelines. Long-term follow-up of children exposed to protease inhibitors in utero is also recommended.

HIV Associated Preeclampsia: A Multifactorial Appraisal

Introduction: This review explores angiogenesis, vascular dysfunction, the complement system, RAAS, apoptosis and NETosis as potential pathways that are dysregulated during preeclampsia, HIV infection and ART usage. Results: HIV-1 accessory and matrix proteins are protagonists for the elevation of oxidative stress, apoptosis, angiogenesis, and elevation of adhesion markers. Despite the immunodeficiency during HIV-1 infection, HIV-1 exploits our cellular defence arsenal by escaping cell-mediated lysis, yet HIV-1 infectivity is enhanced via C5a release of TNF-α and IL-6. This review demonstrates that PE is an oxidatively stressed microenvironment associated with increased apoptosis and NETosis, but with a decline in angiogenesis. Immune reconstitution in the duality of HIV-1 and PE by protease inhibitors, HAART and nucleoside reverse transcriptase, affect similar cellular pathways that eventuate in loss of endothelial cell integrity and, hence, its dysfunction. Conclusions: HIV-1 infection, preeclampsia and ARTs differentially affect endothelial cell function. In the synergy of both conditions, endothelial dysfunction predominates. This knowledge will help us to understand the effect of HIV infection and ART on immune reconstitution in preeclampsia.

Serum levels of vasoactive factors in HIV-infected pre-eclamptic women on HAART

In South Africa, pre-eclampsia (PE) and human immunodeficiency virus (HIV) infection are major causes of pregnancy-related deaths. This study aimed to measure serum levels of endothelin-1 (ET-1), endothelial nitric oxide synthase (eNOS), soluble fms-like tyrosine kinase 1 (sFlt-1), soluble endoglin (sEng) and placental growth factor (PlGF) in HIV-infected highly active antiretroviral therapy (HAART)-treated and HIV-uninfected PE and normotensive women to ascertain if HIV/HAART alters their concentrations. Mean sFlt-1 levels were significantly up-regulated in the PE (HIV-uninfected 4.39 ± 1.29; HIV-infected 5.10 ± 1.10 ng/ml) compared to normotensive women (HIV-uninfected 2.59 ± 0.83; HIV-infected 2.20 ± 0.85 ng/ml). Mean PlGF levels were significantly lower in HIV-uninfected PE vs. HIV-infected normotensive women (29.69 ± 4.47 pg/ml vs. 32.86 ± 6.46 pg/ml; p = .002). In conclusion, PE women with HIV exhibited significantly low serum PlGF, ET-1 and eNOS levels. Infection with HIV may have further increased the sFlt-1 levels.IMPACT STATEMENTWhat is already known on this subject? In PE, the numerous identified local and circulating bioactive factors differed in concentrations when compared to normal pregnancy.What do the results of this study add? PE women with HIV exhibited significantly low serum PlGF, ET-1 and eNOS levels as well as increased levels of sFlt-1.What are the implications of these findings for clinical practice and/or further research? Understanding the link between PE, HIV and HAART during pregnancy will improve prognosis, management and treatment strategies for women clinically.

No association between early antiretroviral therapy during pregnancy and plasma levels of angiogenic factors: a cohort study

Background

Early antiretroviral therapy (ART) during pregnancy has dramatically reduced the risk of perinatal HIV transmission. However, studies have shown an association between premature delivery and the use of ART during pregnancy (particularly protease inhibitor (PI)-based therapies), which could be explained by placental dysfunction. The objective of this study was to evaluate the association of ART (class, duration of exposure and time of initiation) with placental function by using angiogenic factors placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) as biomarkers.

Methods

Clinical and biological data from 159 pregnant women living with HIV were analyzed. Levels of each biomarker were measured in the first and second trimester of pregnancy. After logarithmic transformation, we compared these using generalized estimating equations according to (a) the type of ART; (b) the duration of exposure to ART; and (c) the time of initiation of ART.

Results

After adjusting for variables such as ethnicity, maternal age, gestational age, body mass index, parity, smoking status, and sex of the fetus, we found no significant association between the class of ART (PI-based or not) and serum concentrations of PlGF or sFlt-1. Furthermore, no significant association was found between biomarker levels and the duration of ART exposure or the timing of ART initiation (pre- or post-conception).

Conclusions

This study suggests that first and second trimester angiogenic factor levels are not significantly associated with ART, regardless of the duration or type (with or without PI). These observations seem reassuring when considering the use of ART during early pregnancy.

Human Immunodeficiency Virus and risk of pre-eclampsia and eclampsia in pregnant women: A meta-analysis on cohort studies

Maternal HIV infection is related to several perinatal adverse outcomes. This study is aimed at establishing whether maternal HIV infection is associated with the development of pre-eclampsia (PE) and eclampsia. We comprehensively searched MEDLINE/PubMed, Web of Science, SCOPUS and Embase databases for relevant studies published up to 20 November 2018, without time and language restrictions. We have limited our literature searches to observational studies in humans. We applied a random-effects model to calculate the relative risks (RR) and 95% confidence intervals (CI) for the meta-analyses. We also systematically reviewed eligible studies to determine the effects of HIV infection on imbalance of angiogenic and anti-angiogenic factors, which are effective in increased risk of PE or eclampsia. We identified a total of 11,186 publications, out of which 22 eligible studies (11 prospective and 11 retrospective cohort studies) comprising 90,514 HIV-positive and 66,085,278 HIV-negative pregnant women were included in meta-analysis. Results of the meta-analyses suggested that maternal HIV infection is not significantly associated with the development of PE (RR, 1.04; 95%CI, 0.89-1.21) and eclampsia (RR, 1.05; 95%CI, 0.63-1.75). Six studies were included to understand the effects of HIV infection on imbalance of angiogenic and anti-angiogenic factors. All six studies demonstrated that HIV infection had no significant effect on expression levels of these factors in pre-eclamptic and normotensive pregnant women. Our study showed that maternal HIV infection was not significantly associated with increased or reduced risks of pre-eclampsia and eclampsia. More well-designed studies with large sample size and well defined outcomes are recommended to confirm or refute the present findings.

Angiogenesis, Lymphangiogenesis, and the Immune Response in South African Preeclamptic Women Receiving HAART

Purpose of the review: This review highlights the role of angiogenesis, lymphangiogenesis, and immune markers in human immunodeficiency virus (HIV)-associated preeclamptic (PE) pregnancies in an attempt to unravel the mysteries underlying the duality of both conditions in South Africa. Recent findings: Studies demonstrate that HIV-infected pregnant women develop PE at a lower frequency than uninfected women. In contrast, women receiving highly active anti-retroviral therapy (HAART) are more inclined to develop PE, stemming from an imbalance of angiogenesis, lymphangiogenesis, and immune response. Summary: In view of the paradoxical effect of HIV infection on PE development, this study examines angiogenesis, lymphangiogenesis, and immune markers in the highly HIV endemic area of KwaZulu-Natal. We believe that HAART re-constitutes the immune response in PE, thereby predisposing women to PE development. This susceptibility is due to an imbalance in the angiogenic/lymphangiogenic/immune response as compared to normotensive pregnant women. Further large-scale studies are urgently required to investigate the effect of the duration of HAART on PE development.

A Review of Angiogenic Imbalance in HIV-Infected Hypertensive Disorders of Pregnancy

PURPOSE OF REVIEW

This review provides a comprehensive insight into the angiogenic profile of hypertensive and normotensive pregnancies compromised by HIV infection. Furthermore, we evaluate the economic implementation of the sFlt-1/PlGF ratio and review the reports on therapeutic apheresis in limiting sFlt-1 production.

RECENT FINDINGS

In preeclampsia, an increased expression of sFlt-1 triggers angiogenic imbalance. Women of African ancestry have high levels of angiogenic factors than other racial groups. The sFlt-1/PlGF ratio shows promise in the early assessment of preeclampsia, while sFlt-1 apheresis restores angiogenic imbalance. Studies suggest antiretroviral therapy does not impact the angiogenic shift in preeclampsia development. The angiogenic profile in pregnant women of different races influences preeclampsia development. Despite the opposing immune response in HIV infection and preeclampsia, the HIV tat protein strongly mimics vascular endothelial growth factor (VEGF); hence, it is plausible to assume that HIV infection may ameliorate the angiogenic imbalance in preeclampsia.

Circulating soluble fms-like tyrosine kinase-1, soluble endoglin and placental growth factor during pregnancy in normotensive women in KwaZulu-Natal, South Africa

BACKGROUND

Based on the increased pre-eclampsia and HIV antenatal incidence in South Africa, we determined the angiogenic profiles due to its mechanistic link in preeclampsia development, throughout uncomplicated pregnancies in HIV positive and negative women.

OBJECTIVE

To determine the angiogenic profiles throughout uncomplicated pregnancies in HIV positive and HIV negative women. We explored possible correlations between angiogenic serum levels and selected maternal characteristics (HIV status, gestational age, maternal factors, and pregnancy outcomes).

METHOD

This study was conducted at a primary health care facility in Durban, South Africa. Forty-six pregnant women aged 18-45 years, were enrolled at 10-20, 22-30 and 32-38 weeks' gestation, respectively through convenient sampling. Serum samples were collected and quantitatively evaluated using ELISAs. Clinical and epidemiological data were analysed using STATA (version 14). A probability level of p < 0.05 was considered statistically significant.

RESULTS

Of those enrolled, 28.3% were nulliparous, 82% were HIV positive and none developed pre-eclampsia. Systolic and diastolic blood pressure increased slightly throughout pregnancy. Fluctuating angiogenic and anti-angiogenic levels were demonstrated during pregnancy.

CONCLUSION

This study contributes to the current angiogenic knowledge in normotensive pregnancies, and may assist as a reference range against which these factors may be compared in HIV complicated pregnancies.

Signalling of ERK1/2, P38MAPK and P90RSK in HIV-associated pre-eclampsia

Due to their significance in trophoblast differentiation and survival, we evaluated the expression of the cell signalling molecules; Extracellular signal-regulated kinase 1/2 (ERK1/2), Mitogen Activated Protein Kinase 38 (MAPK38) and p90 ribosomal protein S6 kinase (p90 RSK) in buffy coat samples. Eighty pregnant women attending a large hospital in Durban, South Africa were assigned into normotensive and pre-eclamptic groups and further stratified by their HIV status. The degree of phosphorylation of the analytes was determined using the Bio-Plex Pro^TM Cell Signalling Immunoassay. There was a significantly lower protein concentration of the analytes in the pre-eclamptic versus the normotensive patients, irrespective of HIV status (p < .0001). Also, there was no significant difference in expression of ERK1/2 (p = .4369), p38MAPK (p = .4720) and p90 RSK (p = .0188), according to HIV status. This study demonstrates a down-regulation of ERK1/2, p38MAPK and p90RSK prosurvival markers in pre-eclampsia. This implicates the involvement of the MAPK pathway in the pathogenesis of preeclampsia. Activation of these pathways may prove useful in increasing the body of evidence on prevention of placenta dysfunction and apoptosis. Impact statement What is already known on this subject? Preeclampsia occurring in co-morbidity with HIV is a public health problem among pregnant, black South-African women. There have been conflicting theories regarding the predisposition to the development of preeclampsia as a result of compromised immune response due to HIV infection. In normal pregnancies, the MAPK pathway plays a significant role in molecular processes involved in the cells including survival and differentiation of the placental trophoblast. ERK1/2, p38MAPK and p90RSK are members of the MAPK family, which are pro-apoptotic. Inhibition in the signalling of MAPKs has been found to result in oxidative stress, a process which contributes to the defective trophoblast invasion seen in preeclampsia. What do the results of this study add? The results from this study showed that there is no relationship between HIV infection and an increased predisposition to the development of preeclampsia. In addition, this study highlights a downregulation in the expression of ERK1/2, p38 MAPK and p90RSK in preeclampsia. What are the implications of these findings for clinical practice and/or further research? These findings demonstrate the potential of these analytes as biomarkers for the diagnosis of preeclampsia. Also, this may serve as a framework for further research in the prevention of preeclampsia by elucidating more on the pathway.

Candidate Gene, Genome-Wide Association and Bioinformatic Studies in Pre-eclampsia: a Review

PURPOSE OF REVIEW

Regardless of the familial linkage reported in pre-eclampsia development, understanding the polymorphic genes associated with pre-eclampsia remains limited. Hence, this review aims to outline the main genetic factors that have been investigated in respect to pre-eclampsia development.

RECENT FINDINGS

It is apparent that different genes show significance in varying populations. Notably, it is reported that apolipoprotein-1 gene polymorphisms are associated with pre-eclampsia development in an African-American population, which may be worthwhile to investigate in a Black South African cohort. Despite the research attention that is focused on this surreptitious syndrome, a definitive cause eludes scientists and physicians, alike. Genetic studies can fulfil a dual purpose of suggesting novel hypotheses through genome-wide screening and testing these hypotheses via candidate gene studies. However, publications to date have only presented inconsistent and conflicting results regarding candidate gene analysis.

The Role of Uric Acid in Preeclampsia: Is Uric Acid a Causative Factor or a Sign of Preeclampsia?

PURPOSE OF REVIEW

Because of the significant discrepancies on this topic, this review will focus on the role of uric acid in PE, uric acid as a predictor of preeclampsia and fetal growth retardation. We considered eligible review and original articles relevant to the research question.

RECENT FINDINGS

Hypertensive disorders of pregnancy such as preeclampsia (PE) are a major cause of both maternal and fetal morbidity and mortality worldwide. Uric acid has been reported as a key factor contributing to the pathogenesis of PE. Some studies have indicated that serum uric acid levels increase with the severity of PE, while several studies have shown contradictory results. Some studies suggested high uric acid levels lead to PE, while others state that PE causes an increase in uric acid levels. Despite the strong association of uric acid in the pathogenesis of preeclampsia, current data is still contradictory hence genetic and high-end laboratory investigations may clarify this enigma.

HIV antiretroviral exposure in pregnancy induces detrimental placenta vascular changes that are rescued by progesterone supplementation

Adverse birth outcomes are common in HIV-positive pregnant women receiving combination antiretroviral therapy (cART), especially when cART is initiated in early pregnancy. The mechanisms remain poorly understood. Using a mouse model we demonstrate that protease inhibitor based-cART exposure beginning on day 1 of pregnancy was associated with a pro-angiogenic/pro-branching shift in the placenta driven by lower Flt-1 levels and higher Gcm-1 expression. Micro-CT imaging revealed an increase in the number of arterioles in cART-treated placentas, which correlated with fetal growth restriction. Delaying initiation of cART, or supplementing cART-treated mice with progesterone, prevented the pro-angiogenic/pro-branching shift and the associated placenta vascular changes. In agreement with our mouse findings, we observed an increase in the number of terminal-villi capillaries in placentas from HIV-positive cART-exposed women compared to HIV-negative controls. Capillary number was inversely correlated to maternal progesterone levels. Our study provides evidence that cART exposure during pregnancy influences placenta vascular formation that may in turn contribute to fetal growth restriction. Our findings highlight the need for closer investigation of the placenta in HIV-positive pregnancies, particularly for pregnancies exposed to cART from conception, and suggest that progesterone supplementation could be investigated as a possible intervention to improve placenta function in HIV-positive pregnant women.

Altered angiogenesis as a common mechanism underlying preterm birth, small for gestational age, and stillbirth in women living with HIV

Background

Angiogenic processes in the placenta are critical regulators of fetal growth and impact birth outcomes, but there are limited data documenting these processes in HIV-infected women or women from low-resource settings.

Objective

We sought to determine whether angiogenic factors are associated with adverse birth outcomes in HIV-infected pregnant women started on antiretroviral therapy.

Study Design

This is a secondary analysis of samples collected as part of a clinical trial randomizing pregnant women and adolescents infected with HIV to lopinavir/ritonavir-based (n = 166) or efavirenz-based (n = 160) antiretroviral therapy in Tororo, Uganda. Pregnant women living with HIV were enrolled between 12-28 weeks of gestation. Plasma samples were evaluated for angiogenic biomarkers (angiopoietin-1, angiopoietin-2, vascular endothelial growth factor, soluble fms-like tyrosine kinase-1, placental growth factor, and soluble endoglin) by enzyme-linked immunosorbent assay between: 16-<20, 20-<24, 24-<28, 28-<32, 32-<36, 36-<37 weeks of gestation. The primary outcome was preterm birth.

Results

In all, 1115 plasma samples from 326 pregnant women and adolescents were evaluated. There were no differences in angiogenic factors according to antiretroviral therapy group (P > .05 for all). The incidence of adverse birth outcomes was 16.9% for spontaneous preterm births, 25.6% for small-for-gestational-age births, and 2.8% for stillbirth. We used linear mixed effect modelling to evaluate longitudinal changes in angiogenic factor concentrations between birth outcome groups adjusting for gestational age at venipuncture, maternal age, body mass index, gravidity, and the interaction between treatment arm and gestational age. Two angiogenic factors–soluble endoglin and placental growth factor–were associated with adverse birth outcomes. Significantly higher concentrations of soluble endoglin throughout gestation were found in study participants destined to deliver preterm [likelihood ratio test, χ²(1) = 12.28, P < .0005] and in those destined to have stillbirths [χ²(1) = 5.67, P < .02]. By contrast, significantly lower concentrations of placental growth factor throughout gestation were found in those destined to have small-for-gestational-age births [χ²(1) = 7.89, P < .005] and in those destined to have stillbirths [χ²(1) = 21.59, P < .0001].

Conclusion

An antiangiogenic state in the second or third trimester is associated with adverse birth outcomes, including stillbirth in women and adolescents living with HIV and receiving antiretroviral therapy.

Serum levels of platelet endothelial cell adhesion molecule-1 (PECAM-1) and soluble vascular endothelial growth factor receptor (sVEGFR)-1 and -2 in HIV associated preeclampsia

OBJECTIVE

The angiogenic-antiangiogenic imbalance evident in preeclampsia (PE) may be used as a predictive tool to identify women likely to develop the clinical features in early pregnancy.

METHOD

This retrospective study examined normotensive pregnant (n = 38) and preeclamptic (n = 38) HIV-infected and uninfected women to quantify sVEGFR-1 and -2 and PECAM-1 levels.

RESULTS

In contrast to PECAM-1, sVEGFR-1 and -2 differed according to pregnancy type (p = 0.07; p = 0.001; p = 0.002) but not by HIV status (p = 0.68; p = 0.13; p = 0.43).

CONCLUSION

Irrespective of the HIV status, we report an upregulation of sVEGFR-1 with concomitant decline of PECAM-1 and sVEGFR-2 levels in PE compared to normotensive pregnancies.

Lymphatic vascular endothelial hyaluronan receptor-1 immunoexpression in placenta of HIV infected pre-eclamptic women

INTRODUCTION

Lymphangiogenesis is the formation of new vessels from pre-existing lymphatic vessels. Data on lymphangiogenesis in the placenta of HIV-infected pre-eclamptics are sparse and the findings are conflicting. The aim of this novel study was to evaluate LYVE-1 immunoexpression in the placenta of HIV infected normotensive versus pre-eclamptic women.

METHODS

Placental tissue was obtained from normotensive and pre-eclamptic women stratified according to their HIV status. The pre-eclamptic group was divided into early (<34 weeks) and late (>34 weeks) onset. Immunohistochemistry utilized mouse anti-human LYVE-1 antibody and was morphometrically evaluated.

RESULTS

LYVE-1 immunostaining was localized within endothelium of the arterial supply and venous drainage of both conducting and exchange villi as well as within medial cells of arteries. LYVE-1 immunostained macrophage-like cells were observed within the fetal and maternal circulation. LYVE-1 immunoexpression was higher (p=0.0001) in HIV positive cohort, regardless of pregnancy and villous type. Irrespective of HIV status and pregnancy type, LYVE-1 immunoexpression was significantly elevated in the conducting compared to the exchange villi (p=0.01). LYVE-1 immunoexpression was higher in N and LOPE compared to EOPE groups for both conducting and exchange villi types respectively (p=0.0001 and p=0.006). There is a decrease of LYVE-1 expression in EOPE+ (conducting villi) and EOPE- (exchange villi) compared to N and LOPE subgroups.

CONCLUSION

This study provides a novel insight into an up-regulation of LYVE-1 expression in the fetal circulation of conducting and exchange villi of HIV-infected pre-eclamptics.

Endoglin in HIV-associated preeclamptic placentae

OBJECTIVE

To examine the placental immunoexpression of endoglin (Eng), in HIV-negative and HIV-positive normotensive (N- and N+) and preeclamptic (P- and P+) pregnancies at term, using immunohistochemistry and immunoelectron microscopy.

RESULTS

Strong Eng immunoreactivity was observed within endothelial cells, syncytio- and cyto-trophoblast cell populations. All extravillous trophoblast cells were immunopositive for Eng. Subcellularly, gold particles were immunolocalised within the endoplasmic reticulum, and mitochondria. Immunoexpression of Eng differed significantly between exchange (p = 0.02) and conducting villi (p < 0.001). A higher Eng immunoexpression was observed in both villi types of the preeclamptic compared to normotensive groups. Irrespective of pregnancy type (normotensive versus PE), there was no significant effect of HIV status on Eng immunoexpression within the exchange and conducting villi.

CONCLUSION

The immunostaining of Eng within the endothelial cells, syncytio-, cyto- and extravillous trophoblast cell populations of HIV-associated preeclamptic placentae is novel. Endoglin and its soluble component remains an area for dynamic placental exploration in preeclampsia development.

Is the imbalance between pro-angiogenic and anti-angiogenic factors associated with preeclampsia?

BACKGROUND

Preeclampsia (PE) is a multisystem disease characterized by the development of hypertension and proteinuria. Although PE etiology is not fully known, the placenta seems to play a central role in the development of disease. The inadequate placentation process results in a change in angiogenic factors levels, such as vascular endothelial growth factor (VEGF), placental growth factor (PlGF), soluble form of endoglin (s-Eng) and soluble form of vascular endothelial growth factor receptor type 1 (sFlt-1).

OBJECTIVE

The aim of this review was to clarify if the imbalance between pro-angiogenic and anti-angiogenic factors is associated with PE.

CONCLUSION

It is known that inadequate placentation process is the primary mechanism suggested for PE occurrence and angiogenic factors are involved in this process. The state-of-the-art suggests that progress in grasp the imbalance of pro-angiogenic and anti-angiogenic factors is essential for the improvement of knowledge about PE. The development of prospective, longitudinal studies with serial determinations of these factors throughout pregnancy is needed to better assess the relevance of these markers for understanding the etiology, prevention, diagnosis, prognosis and treatment of this challenging disease.