Can placental growth factors explain birthweight variation in offspring of women with type 1 diabetes?

AIMS/HYPOTHESIS: Maternal hyperglycaemia alone does not explain the incidence of large offspring amongst women with type 1 diabetes. The objective of the study was to determine if there is an association between placental function, as measured by angiogenic factors, and offspring birthweight z score in women with type 1 diabetes. METHODS: This cohort study included samples from 157 Continuous Glucose Monitoring in Pregnant Women with Type 1 Diabetes (CONCEPTT) trial participants. Correlations were estimated between birthweight z score and placental growth factor (PlGF) and soluble fms-like tyrosine kinase (sFlt-1) levels measured at baseline and at 24 and 34 weeks of gestation. Linear regression was used to assess the relationship between birthweight z score and placental health, as measured by PlGF and sFlt-1/PlGF ratio, stratified by glycaemic status (continuous glucose monitoring and HbA1c measures) and adjusted for potential confounders of maternal BMI, smoking and weight gain. Higher PlGF levels and lower sFlt-1/PlGF ratios represent healthy placentas, while lower PlGF levels and higher sFlt-1/PlGF ratios represent unhealthy placentas. RESULTS: Among CONCEPTT participants, the slopes relating PlGF levels to birthweight z scores differed according to maternal glycaemia at 34 weeks of gestation (p = 0.003). With optimal maternal glycaemia (HbA1c < 48 mmol/mol [6.5%]/ or continuous glucose monitoring time above range ≤ 30%), birthweight z scores were reduced towards zero (normal weight) with increasing PlGF values (representing a healthy placenta), and increased with decreasing PlGF values. With suboptimal glycaemic status (HbA1c ≥ 48 mmol/mol [6.5%] or time above range > 30%), increasing PlGF values were associated with heavier infants. Those with a healthy placenta (PlGF > 100) and suboptimal glycaemic control had a higher mean z score (2.45) than those with an unhealthy placenta (mean z score = 1.86). Similar relationships were seen when using sFlt-1/PlGF ratio as a marker for a healthy vs unhealthy placenta. CONCLUSIONS/INTERPRETATION: In women with type 1 diabetes, infant birthweight is influenced by both glycaemic status and placental function. In women with suboptimal glycaemia, infant birthweight was heavier when placentas were healthy. Suboptimal placental function should be considered in the setting of suboptimal glycaemia and apparently 'normal' birthweight.

Evidence for a protective role of placental growth factor in cardiovascular disease.

Placental growth factor (PlGF) is a mitogen for endothelial cells, but it can also act as a proinflammatory cytokine. Because it promotes early stages of plaque formation in experimental models of atherosclerosis and was implicated in epidemiological associations with risk of cardiovascular disease (CVD), PlGF has been attributed a pro-atherogenic role. Here, we investigated whether PlGF has a protective role in CVD and whether elevated PlGF reflects activation of repair processes in response to vascular stress. In a population cohort of 4742 individuals with 20 years of follow-up, high baseline plasma PlGF was associated with increased risk of cardiovascular death, myocardial infarction, and stroke, but these associations were lost or weakened when adjusting for cardiovascular risk factors known to cause vascular stress. Exposure of cultured endothelial cells to high glucose, oxidized low-density lipoprotein (LDL) or an inducer of apoptosis enhanced the release of PlGF. Smooth muscle cells and endothelial cells treated with PlGF small interference RNA demonstrated that autocrine PlGF stimulation plays an important role in vascular repair responses. High expression of PlGF in human carotid plaques removed at surgery was associated with a more stable plaque phenotype and a lower risk of future cardiovascular events. When adjusting associations of PlGF with cardiovascular risk in the population cohort for plasma soluble tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor-2, a biomarker of cellular stress, a high PlGF/TRAIL receptor-2 ratio was associated with a lower risk. Our findings provide evidence for a protective role of PlGF in CVD.

The GEF Trio controls endothelial cell size and arterial remodeling downstream of Vegf signaling in both zebrafish and cell models.

Arterial networks enlarge in response to increase in tissue metabolism to facilitate flow and nutrient delivery. Typically, the transition of a growing artery with a small diameter into a large caliber artery with a sizeable diameter occurs upon the blood flow driven change in number and shape of endothelial cells lining the arterial lumen. Here, using zebrafish embryos and endothelial cell models, we describe an alternative, flow independent model, involving enlargement of arterial endothelial cells, which results in the formation of large diameter arteries. Endothelial enlargement requires the GEF1 domain of the guanine nucleotide exchange factor Trio and activation of Rho-GTPases Rac1 and RhoG in the cell periphery, inducing F-actin cytoskeleton remodeling, myosin based tension at junction regions and focal adhesions. Activation of Trio in developing arteries in vivo involves precise titration of the Vegf signaling strength in the arterial wall, which is controlled by the soluble Vegf receptor Flt1.

Reconciling the distinct roles of angiogenic/anti-angiogenic factors in the placenta and maternal circulation of normal and pathological pregnancies.

A branched vascular network is crucial to placental development and is dependent on factors such as vascular endothelial growth factor (VEGF), placental growth factor (PlGF), angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng) to regulate blood vessel growth. Imbalances in these factors can lead to aberrant placental vascular development. Throughout pregnancy, these factors are also released into the maternal circulation to aid in adapting the maternal cardiovascular system to pregnancy. Increased secretion of anti-angiogenic factors can lead to the development of an anti-angiogenic state in the mother and contribute to the development of pregnancy pathologies such as pre-eclampsia and foetal growth restriction (FGR). Thus, what are commonly referred to as 'angiogenic factors' have distinct functions in the maternal and placental circulations making this a misnomer. Indeed, technical issues in this field such as assay methodology and lack of data considering different placental cell types mean that the physiological roles of these factors in the maternal and placental circulations are frequently muddled in the literature. This review aims to (1) unpick the distinct roles of factors that influence placental vascular development and separate these from the roles of the same factors within the maternal circulation in normal pregnancy and (2) critically assess how imbalances may contribute to the distinct pathophysiological mechanisms underlying pregnancy disorders. Together, this critical assessment of the field endeavours to improve our ability to accurately use these factors as predictive/diagnostic biomarkers in the future.

The Placental Growth Factor Pathway and Its Potential Role in Macular Degenerative Disease.

There is growing evidence that placental growth factor (PlGF) is an important player in multiple pathologies, including tumorigenesis, inflammatory disorders and degenerative retinopathies. PlGF is a member of the vascular endothelial growth factor (VEGF) family and in the retina, binding of this growth factor to specific receptors is associated with pathological angiogenesis, vascular leakage, neurodegeneration and inflammation. Although they share some receptor signalling pathways, many of the actions of PlGF are distinct from VEGF and this has revealed the enticing prospect that it could be a useful therapeutic target for treating early and late stages of diabetic retinopathy (DR) and neovascular age-related macular degeneration (AMD). Recent research suggests that modulation of PlGF could also be important in the geographic atrophy (GA) form of late AMD by protecting the outer retina and the retinal pigment epithelium (RPE). This review discusses PlGF and its signalling pathways and highlights the potential of blocking the bioactivity of this growth factor to treat irreversible visual loss due to the two main forms of AMD.

The role of disordered angiogenesis tissue markers (sflt-1, Plgf) in present day diagnosis of preeclampsia.

Preeclampsia and conditions associated with impaired placental perfusion develop in almost 10% of all pregnancies. Patho- logic angiogenesis is one of the processes observed in preeclampsia. sFlt-1, PlGF and the sFlt-1/PlGF ratio are new and promising angiogenesis-related biomarkers. Our paper describes the present status of, and clinical practice opportunities for, these factors. According to present data, sFlt-1, PlGF and the sFlt-1/PlGF ratio are very useful tools in assessing placental angiogenesis abnormalities associated with preeclampsia and can be use in clinical practice.

The role of placental growth factor (PlGF) and its receptor system in retinal vascular diseases.

Placental growth factor (PlGF) is a member of the vascular endothelial growth factor (VEGF) family. Upon binding to VEGF- and neuropilin-receptor sub-types, PlGF modulates a range of neural, glial and vascular cell responses that are distinct from VEGF-A. As PlGF expression is selectively associated with pathological angiogenesis and inflammation, its blockade does not affect the healthy vasculature. PlGF actions have been extensively described in tumor biology but more recently there has been accumulating preclinical evidence that indicates that this growth factor could have an important role in retinal diseases. High levels of PlGF have been found in aqueous humor, vitreous and/or retina of patients exhibiting retinopathies, especially those with diabetic retinopathy (DR) and neovascular age-related macular degeneration (nvAMD). Expression of this growth factor seems to correlate closely with many of the key pathogenic features of early and late retinopathy in preclinical models. For example, studies using genetic modification and/or pharmacological treatment to block PlGF in the laser-induced choroidal neovascularization (CNV) model, oxygen-induced retinopathy model, as well as various murine diabetic models, have shown that PlGF deletion or inhibition can reduce neovascularization, retinal leakage, inflammation and gliosis, without affecting vascular development or inducing neuronal degeneration. Moreover, an inhibitory effect of PlGF blockade on retinal scarring in the mouse CNV model has also been recently demonstrated and was found to be unique for PlGF inhibition, as compared to various VEGF inhibition strategies. Together, these preclinical results suggest that anti-PlGF therapy might have advantages over anti-VEGF treatment, and that it may have clinical applications as a standalone treatment or in combination with anti-VEGF. Additional clinical studies are clearly needed to further elucidate the role of PlGF and its potential as a therapeutic target in ocular diseases.

The PLGF/c-MYC/miR-19a axis promotes metastasis and stemness in gallbladder cancer.

Gallbladder cancer (GBC) is the most common malignant tumor of the biliary tract system. Epithelial-mesenchymal transition (EMT) plays a vital role in the process of tumor metastasis. Mesenchymal-like cells can serve as a source of cancer stem cells, which can confer the EMT phenotype. Placental growth factor (PLGF) belongs to the vascular endothelial growth factor family and plays a vital role in cancer. However, the underlying molecular mechanisms about the influence of PLGF on EMT in GBC remain unknown. Here we show that PLGF expression levels were higher in GBC tissues than in normal adjacent tissues and were associated with poor prognosis in GBC patients. Exogenous PLGF enhanced the migration, invasion, and tumorsphere formation of GBC cells. Conversely, knockdown of PLGF decreased the aggressive phenotype of GBC cells. Mechanistically, exogenous PLGF upregulated microRNA-19a (miR-19a) expression through the activation of c-MYC. Moreover, Spearman's correlation analysis showed a positive pairwise correlation among PLGF, c-MYC, and miR-19a expression in GBC tissues. Taken together, these results suggest that PLGF promotes EMT and tumorsphere formation through inducing miR-19a expression by upregulating c-MYC. Thus, PLGF could be a promising molecular therapeutic target for GBC.

Placental growth factor and pre-eclampsia.

Placental growth factor (PlGF) is an increasingly important molecule in the prediction, diagnosis and treatment of pre-eclampsia. It has pro-angiogenic effects on the feto-placental circulation and supports trophoblast growth. Mechanisms by which PlGF expression is regulated continue to be investigated. Low circulating PlGF precedes the manifestation of clinical disease in pre-eclamptic pregnancies and intrauterine growth restriction. This suggests that low PlGF is a marker of abnormal placentation, but it remains uncertain whether this is a cause or consequence. Prediction of pre-eclampsia using PlGF is promising and may assist in the targeting of resources to women at highest risk of adverse pregnancy outcomes. Promisingly, experimental animal models of pre-eclampsia have been successfully treated with supplemental PlGF. Treatment of pre-eclampsia with PlGF is a potential therapeutic option requiring further exploration. This review focuses specifically on the role of PlGF in normal and pathological placental development and in the clinical management of pre-eclampsia.

Impacts of Preeclampsia on the Brain of the Offspring / Impactos da pré-eclâmpsia no cérebro de nascituros

Abstract Preeclampsia (PE) is a significant gestational disorder that causes complications in 3- 5% of all human pregnancies. Apart from the immediate risks and complications for mother and fetus, both additionally carry elevated lifelong risks for specific complications. Offspring of PE pregnancies (PE-F1) have higher risks for hypertension, stroke and cognitive impairment compared with well-matched offspring (F1) fromuncomplicated pregnancies. Prior to the clinical onset of PE, placental angiokines secreted into the maternal plasma are deviated. In many PE patients this includes deficits in placental growth factor (PGF). Our laboratory found that mice genetically-deleted for PGF (PGF - / -) have altered cerebrovascular and brain neurological development detectable from midgestation to adulthood. We hypothesized that the PGF deficits seen in human PE, deviate fetal cerebrovascular and neurological development in a manner that impairs cognitive functions and elevates stroke risk. Here we summarize the initial analytical outcomes from a pilot study of 8-10 year old male and female PE-F1s and matched controls. Our studies were the first to report magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) and functional brain region assessment by eyemovement control and clinical psychometric testing in PE-F1s. Further studies in larger cohorts are essential to define whether there are image-based biomarkers that describe unique anatomical features in PE-F1 brains.

Resumo A pré-eclampsia (PE) é importante doença gravídica complicando 3-5% de todas as gestações humanas. Além dos riscos imediatos e complicações para a mãe e o feto, a PE associa-se a outros riscos materno-fetais elevados em longo prazo. Nascituros de gestações complicadas por PE (PE-F1) apresentam maiores riscos de desenvolver hipertensão, acidente vascular cerebral e disfunção cognitiva em comparação com prole (F1) de gestações sem complicações. Antes do aparecimento clínico da PE, angiocitocinas placentárias secretadas no plasma materno apresentam-se alteradas. Em muitos pacientes com PE, isso inclui valores plasmáticos reduzidos de Fator de Crescimento Placentário (PGF). Nosso laboratório identificou que camundongos geneticamente não produtores de PGF (PGF- / - ) apresentam alterações vasculares e de desenvolvimento cerebral detectáveis do período gestacional à idade adulta. Nossa hipótese é que os déficits de PGF identificados em mulheres que desenvolveram PE podem desviar o desenvolvimento neurológico e vascular cerebral fetal, de maneira a prejudicar funções cognitivas, elevando o risco de AVC. Aqui resumimos os resultados analíticos iniciais de um estudo piloto comcrianças do sexomasculino e feminino de 8- 10 anos de idade nascidas de mães que tiveram PE (PE-F1s) comparadas com crianças controle pareadas por idade e sexo. Nossos estudos são os primeiros a relatar a ressonância magnética (RNM), a angiorressonância e a avaliação funcional do cérebro pelo controle de movimento dos olhos e pelo teste clínico psicotécnico em PE-F1s. Estudos adicionais em coortes maiores são essenciais para definir se há biomarcadores com base em imagens que possam descrever características anatômicas únicas em cérebros de crianças PE-F1.

Impacts of Preeclampsia on the Brain of the Offspring.

Preeclampsia (PE) is a significant gestational disorder that causes complications in 3-5% of all human pregnancies. Apart from the immediate risks and complications for mother and fetus, both additionally carry elevated lifelong risks for specific complications. Offspring of PE pregnancies (PE-F1) have higher risks for hypertension, stroke and cognitive impairment compared with well-matched offspring (F1) from uncomplicated pregnancies. Prior to the clinical onset of PE, placental angiokines secreted into the maternal plasma are deviated. In many PE patients this includes deficits in placental growth factor (PGF). Our laboratory found that mice genetically-deleted for PGF (PGF - / - ) have altered cerebrovascular and brain neurological development detectable from midgestation to adulthood. We hypothesized that the PGF deficits seen in human PE, deviate fetal cerebrovascular and neurological development in a manner that impairs cognitive functions and elevates stroke risk. Here we summarize the initial analytical outcomes from a pilot study of 8-10 year old male and female PE-F1s and matched controls. Our studies were the first to report magnetic resonance imaging (MRI), magnetic resonance angiography (MRA) and functional brain region assessment by eye movement control and clinical psychometric testing in PE-F1s. Further studies in larger cohorts are essential to define whether there are image-based biomarkers that describe unique anatomical features in PE-F1 brains.

Placental growth factor (PlGF) and sFlt-1 during pregnancy: physiology, assay and interest in preeclampsia.

The placental growth factor (PlGF) and its soluble receptor (sFlt-1) are circulating angiogenic factors. During pregnancy these factors are released by the placenta into the maternal circulation. Preeclampsia affects 2-7% of pregnant women according to their risk factors and is characterized by high blood pressure and the onset of de novo proteinuria in the second half of pregnancy. Alterations of the sFlt-1/PlGF ratio in preeclampsia correlate with the diagnosis and adverse outcomes, particularly when the disease presents prematurely (<34 weeks). These factors can be assayed in maternal blood and measuring the sFlt-1/PlGF ratio is now available. We propose in this work to update the knowledge of these two molecules, describe their roles and evolution during normal pregnancy and preeclampsia, and finally to focus on the available assays.

Angiogenic balance (sFlt-1/PlGF) and preeclampsia.

Preeclampsia is a hypertensive disorder of pregnancy associated with important maternal and perinatal mortality and morbidity. Although symptomatic management has improved, there is currently no curative treatment, and only childbirth and delivery of the placenta, usually prematurely, alleviate the mother's symptoms. Placental insufficiency plays a central role in the pathophysiology of preeclampsia. Abnormal placentation during the first trimester leads to defective remodeling of the uterine vascularization. This results progressively in placental hypoperfusion, which induces trophoblast dysfunction and the release in maternal circulation of trophoblastic factors leading to an excessive inflammatory response, endothelial dysfunction and glomerular damage. Among these factors, the most important is sFlt-1, which is a soluble form of the VEGF and PlGF receptor. sFlt-1 binds to free VEGF and PlGF in the maternal circulation, thus reducing their bioavailability for their membrane receptor. The result is inhibition of the effects of VEGF and PlGF on maternal endothelial cells and podocytes. The sFlt-1/PlGF ratio reflects the circulating angiogenic balance and is correlated with severity of the disease.