Regulation of placental vascular endothelial growth factor (VEGF) and placenta growth factor (PIGF) and soluble Flt-1 by oxygen--a review

Manganese porphyrin-based treatment improves fetal-placental development and protects against oxidative damage and NLRP3 inflammasome activation in a rat maternal hypothyroidism model

Oxidative stress (OS) and endoplasmic reticulum stress (ERS) are at the genesis of placental disorders observed in preeclampsia, intrauterine growth restriction, and maternal hypothyroidism. In this regard, cationic manganese porphyrins (MnPs) comprise potent redox-active therapeutics of high antioxidant and anti-inflammatory potential, which have not been evaluated in metabolic gestational diseases yet. This study evaluated the therapeutic potential of two MnPs, [MnTE-2-PyP]5+ (MnP I) and [MnT(5-Br-3-E-Py)P]5+ (MnP II), in the fetal-placental dysfunction of hypothyroid rats. Hypothyroidism was induced by administration of 6-Propyl-2-thiouracil (PTU) and treatment with MnPs I and II 0.1 mg/kg/day started on the 8th day of gestation (DG). The fetal and placental development, and protein and/or mRNA expression of antioxidant mediators (SOD1, CAT, GPx1), hypoxia (HIF1α), oxidative damage (8-OHdG, MDA), ERS (GRP78 and CHOP), immunological (TNFα, IL-6, IL-10, IL-1β, IL-18, NLRP3, Caspase1, Gasdermin D) and angiogenic (VEGF) were evaluated in the placenta and decidua on the 18th DG using immunohistochemistry and qPCR. ROS and peroxynitrite (PRX) were quantified by fluorometric assay, while enzyme activities of SOD, GST, and catalase were evaluated by colorimetric assay. MnPs I and II increased fetal body mass in hypothyroid rats, and MnP I increased fetal organ mass. MnPs restored the junctional zone morphology in hypothyroid rats and increased placental vascularization. MnPs blocked the increase of OS and ERS mediators caused by hypothyroidism, showing similar levels of expression of HIFα, 8-OHdG, MDA, Gpx1, GRP78, and Chop to the control. Moreover, MnPs I and/or II increased the protein expression of SOD1, Cat, and GPx1 and restored the expression of IL10, Nlrp3, and Caspase1 in the decidua and/or placenta. However, MnPs did not restore the low placental enzyme activity of SOD, CAT, and GST caused by hypothyroidism, while increased the decidual and placental protein expression of TNFα. The results show that treatment with MnPs improves the fetal-placental development and the placental inflammatory state of hypothyroid rats and protects against oxidative stress and reticular stress caused by hypothyroidism at the maternal-fetal interface.

Exposure to fine particulate matter 2.5 from wood combustion smoke causes vascular changes in placenta and reduce fetal size

During gestation, maternal blood flow to the umbilical cord and placenta increases, facilitating efficient nutrient absorption, waste elimination, and effective gas exchange for the developing fetus. However, the effects of exposure to wood smoke during this period on these processes are unknown. We hypothesize that exposure to PM2.5, primarily sourced from wood combustion for home heating, affects placental vascular morphophysiology and fetal size. We used exposure chambers that received either filtered or unfiltered air. Female rats were exposed to PM2.5 during pre-gestational and/or gestational stages. Twenty-one days post-fertilization, placentas were collected via cesarean section. In these placentas, oxygen diffusion capacity was measured, and the expression of angiogenic factors was analyzed using qPCR and immunohistochemistry. In groups exposed to PM2.5 during pre-gestational and/or gestational stages, a decrease in fetal weight, crown-rump length, theoretical and specific diffusion capacity, and an increase in HIF-1α expression were observed. In groups exposed exclusively to PM2.5 during the pre-gestational stage, there was an increase in the expression of placental genes Flt-1, Kdr, and PIGF. Additionally, in the placental labyrinth region, the expression of angiogenic factors was elevated. Changes in angiogenesis and angiogenic factors reflect adaptations to hypoxia, impacting fetal growth and oxygen supply. In conclusion, this study demonstrates that exposure to PM2.5, emitted from wood smoke, in both pre-gestational and gestational stages, affects fetal development and placental health. This underscores the importance of addressing air pollution in areas with high levels of wood smoke, which poses a significant health risk to pregnant women and their fetuses.

Maternal Blood Angiogenic Factors and the Prediction of Critical Adverse Perinatal Outcomes Among Small-for-Gestational-Age Pregnancies

OBJECTIVE

 Our objective was to determine whether maternal blood angiogenic factors in suspected-small-for-gestational-age (sSGA) fetuses can predict critical adverse perinatal outcomes (CAPO) and improve risk assessment.

METHODS

 Women with singleton pregnancies diagnosed with sSGA, between 24 and 356/7 weeks' gestation, were included. Clinical and sonographic comprehensive evaluations were performed at enrolment. Plasma angiogenic factors, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF), were obtained at diagnosis. In parallel, three attending maternal-fetal-medicine specialists predicted the risk (1-5 scale) of these pregnancies to develop CAPO, based on the clinical presentation. CAPOs were defined as prolonged neonatal intensive care unit hospitalization, fetal or neonatal death, and major neonatal morbidity. Statistical analysis included sensitivity, specificity, positive and negative predictive values, and receiver-operating characteristic (ROC) curve analyses.

RESULTS

 Of the 79 cases included, 32 were complicated by CAPO (40.5%). In SGA fetuses with CAPO, the sFlt-1/PlGF ratio was higher (p < 0.001) and PlGF was lower (p < 0.001) as compared with uncomplicated pregnancies. The areas under the ROC curves for specialists were 0.913, 0.824, and 0.811 and for PlGF and sFlt-1/PlGF ratio 0.926 and 0.900, respectively. CAPO was more common in pregnancies with absent end-diastolic flow or reversed end-diastolic flow (AEDF or REDF) in the umbilical artery upon enrolment (91.6%). Yet, 65.6% of cases involving CAPO occurred in patients without AEDF or REDF, and 66.6% of these cases were not identified by one or more of the experts. The sFlt-1/PlGF ratio identified 92.9% of the experts' errors in this group and 100% of the errors in cases with AEDF or REDF.

CONCLUSION

 Among sSGA pregnancies prior to 36 weeks' gestation, angiogenic factors testing can identify most cases later complicated with CAPO. Our data demonstrate for the first time that these markers can reduce clinician judgment errors. Incorporation of these measures into decision-making algorithms could potentially improve management, outcomes, and even health care costs.

KEY POINTS

· Angiogenic factors at diagnosis of sSGA can be used to predict CAPO.. · The sFlt-1/PlGF ratio can flag sSGA pregnancies at increased risk.. · The sFlt-1/PlGF ratio at admission of sSGA adds to clinical assessment..

Maternal serum biomarkers of placental insufficiency at 24-28 weeks of pregnancy in relation to the risk of delivering small-for-gestational-age infant in Sylhet, Bangladesh: a prospective cohort study

BACKGROUND

Small-for-gestational-age (SGA), commonly caused by poor placentation, is a major contributor to global perinatal mortality and morbidity. Maternal serum levels of placental protein and angiogenic factors are changed in SGA. Using data from a population-based pregnancy cohort, we estimated the relationships between levels of second-trimester pregnancy-associated plasma protein-A (PAPP-A), placental growth factor (PlGF), and serum soluble fms-like tyrosine kinase-1 (sFlt-1) with SGA.

METHODS

Three thousand pregnant women were enrolled. Trained health workers prospectively collected data at home visits. Maternal blood samples were collected, serum aliquots were prepared and stored at -80℃. Included in the analysis were 1,718 women who delivered a singleton live birth baby and provided a blood sample at 24-28 weeks of gestation. We used Mann-Whitney U test to examine differences of the median biomarker concentrations between SGA (< 10th centile birthweight for gestational age) and appropriate-for-gestational-age (AGA). We created biomarker concentration quartiles and estimated the risk ratios (RRs) and 95% confidence intervals (CIs) for SGA by quartiles separately for each biomarker. A modified Poisson regression was used to determine the association of the placental biomarkers with SGA, adjusting for potential confounders.

RESULTS

The median PlGF level was lower in SGA pregnancies (934 pg/mL, IQR 613-1411 pg/mL) than in the AGA (1050 pg/mL, IQR 679-1642 pg/mL; p < 0.001). The median sFlt-1/PlGF ratio was higher in SGA pregnancies (2.00, IQR 1.18-3.24) compared to AGA pregnancies (1.77, IQR 1.06-2.90; p = 0.006). In multivariate regression analysis, women in the lowest quartile of PAPP-A showed 25% higher risk of SGA (95% CI 1.09-1.44; p = 0.002). For PlGF, SGA risk was higher in women in the lowest (aRR 1.40, 95% CI 1.21-1.62; p < 0.001) and 2nd quartiles (aRR 1.30, 95% CI 1.12-1.51; p = 0.001). Women in the highest and 3rd quartiles of sFlt-1 were at reduced risk of SGA delivery (aRR 0.80, 95% CI 0.70-0.92; p = 0.002, and aRR 0.86, 95% CI 0.75-0.98; p = 0.028, respectively). Women in the highest quartile of sFlt-1/PlGF ratio showed 18% higher risk of SGA delivery (95% CI 1.02-1.36; p = 0.025).

CONCLUSIONS

This study provides evidence that PAPP-A, PlGF, and sFlt-1/PlGF ratio measurements may be useful second-trimester biomarkers for SGA.

Impact of Survivin rs9904341 and rs17878467 Polymorphisms On Risk of Preeclampsia in Iran

Preeclampsia (PE) is a hypertensive disorder that affects pregnancy, mother, and fetus. Early diagnosis of PE remains a challenge. This study aimed to investigate the association between survivin two (rs9904341 and rs17878467) SNPs and PE risk in healthy pregnant women compared to women with preeclampsia. A sample of 166 healthy pregnant women and 160 cases with preeclampsia was included and genotyped for rs9904341 with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and rs17878467 with amplification-refractory mutation system (ARMS) PCR. The genotypic and allelic assessments were performed using various statistical approaches. The frequency of rs9904341 and rs17878467 polymorphisms was not significantly different between PE and healthy pregnant women. rs9904341: codominant (p = 0.5), dominant (p = 0.24), recessive (p = 0.61), over-dominant model (p = 0.38), and log additive (p = 0.25). rs17878467: codominant (p = 0.41), dominant (p = 0.23), recessive (p = 0.4), over-dominant model (p = 0.42), and log additive (p = 0.24). The frequency of survivin rs9904341 CG and CC genotypes was higher in severe PE women compared to controls and this polymorphism was associated with PE severity only in the dominant model (OR = 1.84, CI 1.04-3.26, P = 0.034). There was a significant association between survivin rs9904341 polymorphism and PE severity. No relationship was found between survivin rs9904341 and rs17878467 polymorphisms and PE onset. The allelic and genotypic frequencies of survivin rs9904341 and rs17878467 polymorphisms are not significantly different between the preeclampsia and control groups in all genetic models. Haplotype analysis showed lower frequency G rs9904341 T rs17878467 haplotype in PE woman and this haplotype was associated with lower risk of PE (OR = 0.54, CI 0.33-0.91, P = 0.02).

Effect of Aromatase Inhibitor Letrozole on the Placenta of Adult Albino Rats: A Histopathological, Immunohistochemical, and Biochemical Study

Background

Letrozole, an aromatase inhibitor, has recently been introduced as the preferred treatment option for ectopic pregnancy. To date, no study has investigated the effect of letrozole alone on placental tissue. The present study aimed to evaluate the effect of different doses of letrozole on the placenta of rats and to clarify the underlying mechanism.

Methods

Sixty pregnant female rats were equally divided into three groups, namely the control group (GI), low-dose (0.5 mg/Kg/day) letrozole group (GII), which is equivalent to the human daily dose (HED) of 5 mg, and high-dose (1 mg/Kg/day) letrozole group (GIII), equivalent to the HED of 10 mg. Letrozole was administered by oral gavage daily from day 6 to 16 of gestation. Data were analyzed using a one-way analysis of variance followed by Tukey's post hoc test and Chi square test. P<0.05 was considered statistically significant.

Results

Compared to the GI and GII groups, high-dose letrozole significantly increased embryonic mortality with a high post-implantation loss rate (P<0.001) and significantly reduced the number of viable fetuses (P<0.001) and placental weight (P<0.001) of pregnant rats. Moreover, it significantly reduced placental estrogen receptor (ER) and progesterone receptor (PR) (P<0.001) and the expression of vascular endothelial growth factor (P<0.001), while increasing the apoptotic index of cleaved caspase-3 (P<0.001).

Conclusion

Letrozole inhibited the expression of ER and PR in rat placenta. It interrupted stimulatory vascular signals causing significant apoptosis and placental vascular dysfunction. Letrozole in an equivalent human daily dose of 10 mg caused a high post-implantation loss rate without imposing severe side effects.

From Biomarkers to the Molecular Mechanism of Preeclampsia-A Comprehensive Literature Review

Preeclampsia (PE) is a prevalent obstetric illness affecting pregnant women worldwide. This comprehensive literature review aims to examine the role of biomarkers and understand the molecular mechanisms underlying PE. The review encompasses studies on biomarkers for predicting, diagnosing, and monitoring PE, focusing on their molecular mechanisms in maternal blood or urine samples. Past research has advanced our understanding of PE pathogenesis, but the etiology remains unclear. Biomarkers such as PlGF, sFlt-1, PP-13, and PAPP-A have shown promise in risk classification and preventive measures, although challenges exist, including low detection rates and discrepancies in predicting different PE subtypes. Future perspectives highlight the importance of larger prospective studies to explore predictive biomarkers and their molecular mechanisms, improving screening efficacy and distinguishing between early-onset and late-onset PE. Biomarker assessments offer reliable and cost-effective screening methods for early detection, prognosis, and monitoring of PE. Early identification of high-risk women enables timely intervention, preventing adverse outcomes. Further research is needed to validate and optimize biomarker models for accurate prediction and diagnosis, ultimately improving maternal and fetal health outcomes.

Longitudinal Associations between Ambient Air Pollution and Angiogenic Biomarkers among Pregnant Women in the LIFECODES Study, 2006-2008

BACKGROUND

Exposures to ambient air pollution during pregnancy have been linked to adverse pregnancy outcomes such as preeclampsia and fetal growth restriction. Although evidence has shown that women with preeclampsia have higher ratio of soluble fms-like tyrosine kinase 1 to placental growth factor (sFlt-1/PlGF ratio), the potential impact of air pollution on markers of placental growth and function has not been well studied.

OBJECTIVES

We aimed to examine longitudinal associations between ambient air pollution exposure and angiogenic factors among pregnant women in LIFECODES, a prospective birth cohort and biorepository in Massachusetts in the United States.

METHODS

PlGF and sFlt-1 were measured among pregnant women using plasma samples collected around 10, 18, 26, and 35 wk' gestation. Women's exposures to ozone (O 3 ), fine particulate matter with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ), and nitrogen dioxide (NO 2 ) within 1, 2, 4, and 8 wk prior to each plasma sample collection were estimated based on geocoded residential addresses, and mixed effect linear regression models were fitted to assess their associations with sFlt-1/PlGF ratio, sFlt-1 (ng/mL), and PlGF (pg/mL). Percent changes in outcomes associated with each interquartile range increase in exposures were reported, along with their 95% confidence intervals.

RESULTS

A total of 1,066 pregnant women were included. In the multipollutant models, significant associations were observed for increased sFlt-1/PlGF ratio (PM 2.5 3-8 wk' gestation, NO 2 : 35-39 wk' gestation), elevated sFlt-1 (O 3 : 26-34 wk' gestation, PM 2.5 : 3-8 wk' gestation), decreased sFlt-1 (NO 2 : 4-8 wk' gestation), and decreased PlGF (NO 2 : 34-39 wk' gestation) after adjusting for sociodemographic status, smoking, drinking, body mass index, parity, history of chronic hypertension, and conception time.

DISCUSSION

Exposures to PM 2.5 during early pregnancy and exposures to O 3 and NO 2 during late pregnancy were associated with increased sFlt-1/PlGF ratio, elevated sFlt-1 and with decreased PlGF, which may be a potential mechanism underlying ambient air pollution's impacts on adverse pregnancy and birth outcomes. https://doi.org/10.1289/EHP11909.

Clinical progress of anti-angiogenic targeted therapy and combination therapy for gastric cancer

The incidence of gastric cancer is increasing year by year. Most gastric cancers are already in the advanced stage with poor prognosis when diagnosed, which means the current treatment is not satisfactory. Angiogenesis is an important link in the occurrence and development of tumors, and there are multiple anti-angiogenesis targeted therapies. To comprehensively evaluate the efficacy and safety of anti-angiogenic targeted drugs alone and in combination against gastric cancer, we systematically searched and sorted out relevant literature. In this review, we summarized the efficacy and safety of Ramucirumab, Bevacizumab, Apatinib, Fruquintinib, Sorafenib, Sunitinib, Pazopanib on gastric cancer when used alone or in combination based on prospective clinical trials reported in the literature, and sorted response biomarkers. We also summarized the challenges faced by anti-angiogenesis therapy for gastric cancer and available solutions. Finally, the characteristics of the current clinical research are summarized and suggestions and prospects are raised. This review will serve as a good reference for the clinical research of anti-angiogenic targeted drugs in the treatment of gastric cancer.

Monosodium Glutamate Perturbs Human Trophoblast Invasion and Differentiation through a Reactive Oxygen Species-Mediated Pathway: An In-Vitro Assessment

The overproduction of reactive oxygen species (ROS) has been associated with various human diseases. ROS exert a multitude of biological effects with both physiological and pathological consequences. Monosodium glutamate (MSG), a sodium salt of the natural amino acid glutamate, is a flavor-enhancing food additive, which is widely used in Asian cuisine and is an ingredient that brings out the “umami” meat flavor. MSG consumption in rats is associated with ROS generation. Owing to its consumption as part of the fast-food culture and concerns about its possible effects on pregnancy, we aimed to study the impact of MSG on placental trophoblast cells. MSG exposure influenced trophoblast invasion and differentiation, two of the most critical functions during placentation through enhanced production of ROS. Similar findings were also observed on MSG-treated placental explants, as confirmed by elevated Nrf2 levels. Ultrastructural studies revealed signs of subcellular injury by MSG exposure. Mechanistically, MSG-induced oxidative stress with endoplasmic reticulum stress pathways involving Xbp1s and IRE1α was observed. The effect of MSG through an increased ROS production indicates that its long-term exposure might have adverse health effect by compromising key trophoblast functions.

Placental Growth Factor and Pregnancy-Associated Plasma Protein-A as Potential Early Predictors of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications and one of the main causes of adverse pregnancy outcomes. An early diagnosis of GDM is of fundamental importance in clinical practice. However, the major professional organizations recommend universal screening for GDM, using a 75 g oral glucose tolerance test at 24-28 weeks of gestation. A selective screening at an early stage of pregnancy is recommended only if there are maternal risk factors for diabetes. As a result, the GDM diagnosis is often delayed and established after the appearance of complications. The manifestation of GDM is directly related to insulin resistance, which is closely associated with endothelial dysfunction. The placenta, the placental peptides and hormones play a pivotal role in the manifestation and progression of insulin resistance during pregnancy. Recently, the placental growth factor (PlGF) and plasma-associated protein-A (PAPP-A), have been shown to significantly affect both insulin sensitivity and endothelial function. The principal function of PAPP-A appears to be the cleavage of circulating insulin-like growth factor binding protein-4 while PlGF has been shown to play a central role in the development and maturation of the placental vascular system and circulation. On one hand, these factors are widely used as early predictors (11-13 weeks of gestation) of complications during pregnancy, such as preeclampsia and fetal aneuploidies, in most countries. On the other hand, there is increasing evidence for their predictive role in the development of carbohydrate disorders, but some studies are rather controversial. Therefore, this review aims to summarize the available literature about the potential of serum levels of PlGF and PAPP-A as early predictors in the diagnosis of GDM.

Definition and Quantification of Three-Dimensional Imaging Targets to Phenotype Pre-Eclampsia Subtypes: An Exploratory Study

Pre-eclampsia is a severe placenta-related complication of pregnancy with limited early diagnostic and therapeutic options. Aetiological knowledge is controversial, and there is no universal consensus on what constitutes the early and late phenotypes of pre-eclampsia. Phenotyping of native placental three-dimensional (3D) morphology offers a novel approach to improve our understanding of the structural placental abnormalities in pre-eclampsia. Healthy and pre-eclamptic placental tissues were imaged with multiphoton microscopy (MPM). Imaging based on inherent signal (collagen, and cytoplasm) and fluorescent staining (nuclei, and blood vessels) enabled the visualization of placental villous tissue with subcellular resolution. Images were analysed with a combination of open source (FIJI, VMTK, Stardist, MATLAB, DBSCAN), and commercially (MATLAB) available software. Trophoblast organization, 3D-villous tree structure, syncytial knots, fibrosis, and 3D-vascular networks were identified as quantifiable imaging targets. Preliminary data indicate increased syncytial knot density with characteristic elongated shape, higher occurrence of paddle-like villous sprouts, abnormal villous volume-to-surface ratio, and decreased vascular density in pre-eclampsia compared to control placentas. The preliminary data presented indicate the potential of quantifying 3D microscopic images for identifying different morphological features and phenotyping pre-eclampsia in placental villous tissue.

Increased Placental sFLT1 (Soluble fms-Like Tyrosine Kinase Receptor-1) Drives the Antiangiogenic Profile of Maternal Serum Preceding Preeclampsia but Not Fetal Growth Restriction

BACKGROUND

Preeclampsia and fetal growth restriction (FGR) are both associated with an increased ratio of sFLT1 (soluble fms-like tyrosine kinase-1) to PlGF (placenta growth factor) in maternal serum. In preeclampsia, it is assumed that increased placental release of sFLT1 results in PlGF being bound and inactivated. However, direct evidence for this model is incomplete, and it is unclear whether the same applies in FGR.

METHODS

We conducted a prospective cohort study where we followed 4212 women having first pregnancies from their dating ultrasound, obtained blood samples serially through the pregnancy, and performed systematic sampling of the placenta after delivery. The aim of the present study was to determine the relationship between protein levels of sFLT1 and PlGF in maternal serum measured at ≈36 weeks and placental tissue lysates obtained after term delivery in 82 women with preeclampsia, 50 women with FGR, and 132 controls.

RESULTS

The sFLT1:PlGF ratio was increased in both preeclampsia and FGR in both the placenta and maternal serum. However, in preeclampsia, the maternal serum ratio of sFLT1:PlGF was strongly associated with placental sFLT1 level (r=0.45; P<0.0001) but not placental PlGF level (r=-0.17; P=0.16). In contrast, in FGR, the maternal serum ratio of sFLT1:PlGF was strongly associated with placental PlGF level (r=-0.35; P=0.02) but not sFLT1 level (r=0.04; P=0.81).

CONCLUSIONS

We conclude that the elevated sFLT1:PlGF ratio is primarily driven by increased placental sFLT1 in preeclampsia, whereas in FGR, it is primarily driven by decreased placental PlGF.

The role of the placenta in spontaneous preterm labor and delivery with intact membranes

OBJECTIVES

To determine whether placental vascular pathology and impaired placental exchange due to maturational defects are involved in the etiology of spontaneous preterm labor and delivery in cases without histologic acute chorioamnionitis.

METHODS

This was a retrospective, observational study. Cases included pregnancies that resulted in spontaneous preterm labor and delivery (<37 weeks), whereas uncomplicated pregnancies that delivered fetuses at term (≥37-42 weeks of gestation) were selected as controls. Placental histological diagnoses were classified into three groups: lesions of maternal vascular malperfusion, lesions of fetal vascular malperfusion, and placental microvasculopathy, and the frequency of each type of lesion in cases and controls was compared. Moreover, we specifically searched for villous maturational abnormalities in cases and controls. Doppler velocimetry of the umbilical and uterine arteries were performed in a subset of patients.

RESULTS

There were 184 cases and 2471 controls, of which 95 and 1178 had Doppler studies, respectively. The frequency of lesions of maternal vascular malperfusion was greater in the placentas of patients with preterm labor than in the control group [14.1% (26/184) vs. 8.8% (217/2471) (p=0.023)]. Disorders of villous maturation were more frequent in the group with preterm labor than in the control group: 41.1% (39/95) [delayed villous maturation in 31.6% (30/95) vs. 2.5% (13/519) in controls and accelerated villous maturation in 9.5% (9/95) vs. none in controls].

CONCLUSIONS

Maturational defects of placental villi were associated with approximately 41% of cases of unexplained spontaneous preterm labor and delivery without acute inflammatory lesions of the placenta and with delivery of appropriate-for-gestational-age fetuses.

Association between placenta accreta spectrum and third-trimester serum levels of vascular endothelial growth factor, placental growth factor, and soluble Fms-like tyrosine kinase-1: A meta-analysis

AIM

Antenatal suspicion of placenta accreta spectrum (PAS) currently relies on ultrasonographic findings, color doppler, and MRI, which have rendered it operator and expertise-dependent. No serum markers for PAS have been integrated into clinical practice yet. The aim of this meta-analysis was to identify potential serum markers for PAS by investigating third-trimester serum levels of vascular endothelial growth factor (VEFG), placental growth factor (PIGF), and soluble Fms-like tyrosine kinase-1 (sFlt-1) among PAS-cases and controls.

METHODS

PubMed, Scopus, EBSCO, Web of Science, and CNKI databases were systematically searched for relevant articles. Random-effects model was applied to calculate the overall standardized mean difference (SMD) for each marker. Subgroup analysis and meta-regression were performed to assess for potential covariates.

RESULTS

Eight studies involving 366 PAS-cases and 518 controls were included. Third trimester sFlt-1 levels were significantly lower in PAS-cases when compared to controls (SMD = -7.76, 95%CI = -10.42 to -5.10). This was, to a certain extent, consistent among studies though they differed in their extent of significance. Levels of VEGF (SMD = 1.59, 95%CI = -0.07 to 3.25) and PlGF (SMD = -0.49, 95%CI = -1.66 to 0.67) were not significantly different between PAS cases and controls, in which studies demonstrated conflicting results.

CONCLUSIONS

Third trimester sFlt-1 levels may be useful to predict PAS. Nonetheless, further studies are recommended to better understand conflicting results before adopting either VEGF or PlGF.

Evaluation of Different Doses of the Aromatase Inhibitor Letrozole for the Treatment of Ectopic Pregnancy and Its Effect on Villous Trophoblastic Tissue

Letrozole, an aromatase inhibitor, has recently been introduced as a favorable medical treatment for ectopic pregnancy. We aimed at evaluating the effects of different doses of letrozole for termination of ectopic pregnancy and study their effects on villous trophoblastic tissue. Sixty patients with undisturbed ectopic pregnancy were classified into three equal groups. Group I: the control group that contained women who underwent laparoscopic salpingectomy, Group II: patients who received letrozole (5 mg day⁻¹) for 10 days, and Group III: patients who received letrozole (10 mg day⁻¹) for 10 days. Subsequently, the β-hCG levels were determined on the first day and after 11 days of treatment. Group IV consisted of patients of GII and GIII; their β-hCG did not drop below 100 mIU/ml within 11 days, and underwent salpingectomy. Placental tissues from patients undergoing salpingectomy either from the control group or GIV were processed for the evaluation of estrogen (ER) and progesterone (PR) receptors, vascular endothelial growth factor (VEGF), and cleaved caspase 3 (CC-3) expression. Cases exposed to high dose letrozole 10 mg day⁻¹ resulted in a higher ectopic pregnancy resolution rate of 85% (17/20), while the resolution rate of the low dose letrozole-treated group (5 mg day⁻¹) was 65% (13/20), and also showed a significant reduction in β-hCG levels on the 11th day, 25.63 ± 4.29 compared to the low dose letrozole group 37.91 ± 7.18 (P < 0.001), Meanwhile, the letrozole-treated group GIV showed markedly reduced expression of ER, PR, and VEGF and a significant increase in the apoptotic index cleaved caspase-3 compared to the control group (P < 0.001). The utilization of letrozole at a dose of 10 mg day⁻¹ for medical treatment of ectopic pregnancy results in a high-successful rate without any severe side effects. Letrozole depriving the placenta of estrogen that had vascular supporting signals resulted in destroying the vascular network with marked apoptosis.

AT2R activation increases in vitro angiogenesis in pregnant human uterine artery endothelial cells

Angiogenesis is vital during pregnancy for remodeling and enhancing vasodilation of maternal uterine arteries, and increasing uterine blood flow. Abnormal angiogenesis is associated with decreased uteroplacental blood flow and development of pregnancy disorders such as gestational hypertension, preeclampsia, fetal growth restriction, preterm delivery, stillbirth, and miscarriage. The mechanisms that contribute to normal angiogenesis remain obscure. Our previous studies demonstrated that expression of the angiotensin type 2 receptor (AT2R) is increased while the angiotensin type 1 receptor (AT1R) is unchanged in the endothelium of uterine arteries, and that AT2R-mediated pregnancy adaptation facilitates enhanced vasodilation and uterine arterial blood flow. However, the role of AT2R in regulating angiogenesis during pregnancy has never been studied. This study examines whether or not AT2R activation induces angiogenesis and, if so, what mechanisms are involved. To this end, we used primary human uterine artery endothelial cells (hUAECs) isolated from pregnant and nonpregnant women undergoing hysterectomy. The present study shows that Compound 21, a selective AT2R agonist, induced proliferation of pregnant-hUAECs, but not nonpregnant-hUAECs, in a concentration-dependent manner, and that this C21-induced mitogenic effect was blocked by PD123319, a selective AT2R antagonist. The mitogenic effects induced by C21 were inhibited by blocking JNK—but not ERK, PI3K, and p38—signaling pathways. In addition, C21 concentration dependently increased cell migration and capillary-like tube formation in pregnant-hUAECs. The membrane-based antibody array showed that C21 increased expression of multiple angiogenic proteins, including EGF, bFGF, leptin, PLGF, IGF-1, and angiopoietins. Our qPCR analysis demonstrates that C21-induced increase in expression of these angiogenic proteins correlates with a proportional increase in mRNA expression, indicating that AT2R activates angiogenic proteins at the transcriptional level. In summary, the present study shows that AT2R activation induces angiogenesis of hUAECs in a pregnancy-specific manner through JNK-mediated pathways with associated transcriptional upregulation of multiple proangiogenic proteins.

The function of nuclear hormone receptor 4A signaling in the human reproductive system: A review

AIM

This review aims to summarize the research focused upon the functions of nuclear hormone receptor 4A (NR4A) in the human reproductive system. The research questions addressed are to decipher what role the NR4A subfamily plays in the regulation of the human reproductive system and effects upon fertility issues through regulation of the expression of the NR4A subfamily.

METHODS

The electronic database PubMed was searched for studies published before November 2021. Keywords included "NR4A," "trophoblast," "decidualization," "folliculogenesis," "estrogen," "pregnancy," "Leydig cells," "fertility," and "reproductive." Relevant references from retrieved manuscripts and review articles were also searched manually.

RESULTS

NR4A subfamily are involved in trophoblast differentiation, endometrial decidualization, embryo adhesion, secretion of related hormones, and regulation of spontaneous term labor. Besides, many studies have provided strong evidence that they play critical roles in spermatogenesis. Furthermore, Multiple mechanisms can affect the expression of NR4As. Broadly, NR4A family receptors affect the human reproductive system in multiple ways.

CONCLUSIONS

Further research is needed to specifically dissect the functions and regulatory mechanisms of these receptors and their pharmaceutical antagonists and agonists. The connection between the NR4A subfamily and a variety of reproductive disorders needs to be proven experimentally such that further examination of human tissue is required to assess the role of these receptors in human reproductive diseases.

Uterine damage induces placenta accreta and immune imbalance at the maternal-fetal interface in the mouse

INTRODUCTION

Placenta accreta spectrum (PAS) disorder is one of the major complications resulting in maternal death and serious adverse pregnancy outcomes. Uterine damage - principally that associated with cesarean section - is the leading risk factor for the development of PAS. However, the underlying pathogenesis of PAS related to uterine damage remains unclear.

METHODS

For this study, we constructed a mouse PAS model using hysterotomy to simulate a cesarean section in humans. Pregnant mice were sacrificed on embryonic days 12.5 (E12.5) and E17.5. Trophoblast invasion and placental vascularization were analyzed using Hematoxylin-Eosin (H&E) staining and immunohistochemistry (IHC), and the proportions of immune cells at the maternal-fetal interface were analyzed using flow cytometry. We analyzed the expressions of genes in the decidua and placenta using RNA sequencing and subsequent validation by QPCR, and measured serum angiogenic factors by ELISA.

RESULTS

Uterine damage led to increased trophoblast invasion and placental vascularization, with extensive changes to the immune-cell profiles at the maternal-fetal interface. The proportions of T and NK cells in the deciduas diminished significantly, with the decidual NK cells and M - 2 macrophages showing the greatest decline. The expression of TNF-α and IL4 was upregulated in the deciduas, while that of IFN-γ and IL10 was downregulated significantly. The expression of Mmp2, Mmp9, Mmp3, and Dock4 was significantly elevated in the placenta, and the serum levels of anti-angiogenic factors were significantly attenuated.

DISCUSSION

Uterine damage can cause immune imbalance at the maternal-fetal interface, which may contribute to abnormal trophoblast invasion and enhanced vascularization of the mouse placenta.

The Role of Placental Growth Factor in the Prediction of Carbohydrate and Thyroid Disorders during Pregnancy

Background and objectives: To assess whether placental growth factor (PlGF) levels may have a predictive value for the onset of gestational diabetes mellitus (GDM) and thyroid dysfunction during pregnancy. Materials and Methods: This single-center retrospective analysis was conducted at the Specialized Hospital for Active Treatment in Obstetrics and Gynecology “Dr. Shterev”, Sofia, Bulgaria, from December 2017 to December 2019. Using pregnant women’s electronic records, we analyzed and compared the data of 412 women diagnosed with GDM and 250 women without evidence for carbohydrate disorders. Thyroid function was tested in all patients at the time of performing GDM screening. The following measurements were compared and assessed: body mass index (BMI), fasting blood glucose levels, thyroid-stimulating hormone levels (TSH), free thyroxine, and triiodothyronine (FT4 and FT3) levels, and serum placental growth factor (PlGF). The sensitivity and specificity of PlGF as a predictive marker for GDM and thyroid dysfunction were analyzed using receiver operating characteristic (ROC) curves. Results: There were no significant differences between GDM and control groups in terms of age and BMI (p > 0.05). In patients with established GDM, the PlGF corrected multiple of the median (MoM) was significantly higher compared to the control group (0.9 vs. 0.7, p < 0.001). The ROC-AUC for the prediction of GDM and thyroid dysfunction during pregnancy was 0.68 (95% CI 0.64–0.72) and 0.61 (95% CI 0.57–0.65), respectively. Conclusions: Our results underscore the potential role of PlGF as a biomarker in the prediction and diagnosis of GDM and thyroid dysfunction during pregnancy.

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.

Effect of swimming exercise, insulin-associated or not, on inflammatory cytokines, apoptosis, and collagen in diabetic rat placentas

Physical exercise is an important therapeutic agent for women with diabetes during gestation. However, its histophysiological consequences for the placenta remain unclear. In this study, we evaluated the expression of VEGF-A, IL1ß, TNFα, and type I collagen in the placentas of diabetic rats subjected to a swimming program. Thirty rats were divided into the following groups: CG, pregnant nondiabetic rats; CEG, nondiabetic pregnant rats subjected to swimming; DG, pregnant diabetic rats; DEG, pregnant diabetic rats subjected to swimming; DIG, pregnant diabetic rats treated with insulin; DIEG, pregnant diabetic rats treated with insulin and subjected to swimming. Diabetes was induced using streptozotocin [50 mg/kg intraperitoneally (i.p.)], and insulin was administered at a dose of 5 U/day i.p. (2 U at 10 am and 3 U at 7 pm) in the DIG group; in the DIEG group, insulin was administered at a dose of only 2 U/day at 7 pm. The rats were sacrificed on the 20th day of gestation. There was an increase in the expression of IL-1β, TNF-α, VEGF-A, and type I collagen and a higher apoptotic index in the placentas of the DG and DEG groups, but there was a reduction in glycemia in the latter group. In the DIG and DIEG groups, the levels remained similar to those of the control; however, in these groups the reduction was more significant for all analyzed parameters. Therefore, in rats induced to diabetes during pregnancy, swimming, although reducing glycemic levels, did not prevent immunohistochemical changes in the placenta, suggesting the need for a multidisciplinary protocol associated with traditional pharmacological treatment.

Kisspeptin treatment improves fetal-placental development and blocks placental oxidative damage caused by maternal hypothyroidism in an experimental rat model

Maternal hypothyroidism is associated with fetal growth restriction, placental dysfunction, and reduced kisspeptin/Kiss1R at the maternal-fetal interface. Kisspeptin affects trophoblastic migration and has antioxidant and immunomodulatory activities. This study aimed to evaluate the therapeutic potential of kisspeptin in the fetal-placental dysfunction of hypothyroid Wistar rats. Hypothyroidism was induced by daily administration of propylthiouracil. Kisspeptin-10 (Kp-10) treatment was performed every other day or daily beginning on day 8 of gestation. Feto-placental development, placental histomorphometry, and expression levels of growth factors (VEGF, PLGF, IGF1, IGF2, and GLUT1), hormonal (Dio2) and inflammatory mediators (TNFα, IL10, and IL6), markers of hypoxia (HIF1α) and oxidative damage (8-OHdG), antioxidant enzymes (SOD1, Cat, and GPx1), and endoplasmic reticulum stress mediators (ATF4, GRP78, and CHOP) were evaluated on day 18 of gestation. Daily treatment with Kp-10 increased free T3 and T4 levels and improved fetal weight. Both treatments reestablished the glycogen cell population in the junctional zone. Daily treatment with Kp-10 increased the gene expression levels of Plgf, Igf1, and Glut1 in the placenta of hypothyroid animals, in addition to blocking the increase in 8-OHdG and increasing protein and/or mRNA expression levels of SOD1, Cat, and GPx1. Daily treatment with Kp-10 did not alter the higher protein expression levels of VEGF, HIF1α, IL10, GRP78, and CHOP caused by hypothyroidism in the junctional zone compared to control, nor the lower expression of Dio2 caused by hypothyroidism. However, in the labyrinth zone, this treatment restored the expression of VEGF and IL10 and reduced the GRP78 and CHOP immunostaining. These findings demonstrate that daily treatment with Kp-10 improves fetal development and placental morphology in hypothyroid rats, blocks placental oxidative damage, and increases the expression of growth factors and antioxidant enzymes in the placenta.

β3-Adrenoceptor, a novel player in the round-trip from neonatal diseases to cancer: Suggestive clues from embryo

The role of the β-adrenoceptors (β-ARs) in hypoxia-driven diseases has gained visibility after the demonstration that propranolol promotes the regression of infantile hemangiomas and ameliorates the signs of retinopathy of prematurity (ROP). Besides the role of β2-ARs, preclinical studies in ROP have also revealed that β3-ARs are upregulated by hypoxia and that they are possibly involved in retinal angiogenesis. In a sort of figurative round trip, peculiarities typical of ROP, where hypoxia drives retinal neovascularization, have been then translated to cancer, a disease equally characterized by hypoxia-driven angiogenesis. In this step, investigating the role of β3-ARs has taken advantage of the assumption that cancer growth uses a set of strategies in common with embryo development. The possibility that hypoxic induction of β3-ARs may represent one of the mechanisms through which primarily embryo (and then cancer, as an astute imitator) adapts to grow in an otherwise hostile environment, has grown evidence. In both cancer and embryo, β3-ARs exert similar functions by exploiting a metabolic shift known as the Warburg effect, by acquiring resistance against xenobiotics, and by inducing a local immune tolerance. An additional potential role of β3-AR as a marker of stemness has been suggested by the finding that its antagonism induces cancer cell differentiation evoking that β3-ARs may help cancer to grow in a nonhospital environment, a strategy also exploited by embryos. From cancer, the round trip goes back to neonatal diseases for which new possible interpretative keys and potential pharmacological perspectives have been suggested.

miRNAs in decidual NK cells: regulators worthy of attention during pregnancy

The critical immune effectors, including T, B, and natural killer (NK) cells, dendritic cells, and macrophages participate in regulating immune responses during pregnancy. Among these immune cells, decidual NK (dNK) cells are involved in key placental development processes at the maternal-fetal interface, such as uterine spiral artery remodeling, trophoblast invasion, and decidualization. Mechanistically, dNK cells significantly influence pregnancy outcome by secreting cytokines, chemokines, and angiogenic mediators and by their interactions with trophoblasts and other decidual cells. MicroRNAs (miRNAs) are small non-coding RNA molecules that participate in the initiation and progression of human diseases. Although the functions of circulating miRNAs in pathological mechanism has been extensively studied, the regulatory roles of miRNAs in NK cells, especially in dNK cells, have been rarely reported. In this review, we analyze the effects of miRNA regulations of dNK cell functions on the immune system during gestation. We discuss aberrant expressions of certain miRNAs in dNK cells that may lead to pathological consequences, such as recurrent pregnancy loss (RPL). Interestingly, miRNA expression patterns are also different between dNK cells and peripheral NK (pNK) cells, and pNK cells in the first- and third-trimester of gestation. The dysregulation of miRNA plays a pivotal regulatory role in driving immune functions of dNK and pNK cells. Further understanding of the molecular mechanisms of miRNAs in dNK cells may provide new insights into the development of therapeutics to prevent pregnancy failure.

Predictive value of vascular endothelial growth factor and placenta growth factor for placenta accreta spectrum

This study aimed to assess the maternal features, Vascular Endothelial Growth Factor (VEGF) and Placenta Growth Factor (PLGF) in the Placenta Accreta Spectrum (PAS); then, to determine a predictive value of VEGF and PLGF in the PAS. This prospective case-control study was conducted on 90 pregnant women including 45 PAS, and 45 Normal Placenta (NP). Maternal age, gravidity, C/S, and serum levels of VEGF and PLGF were assessed between NP and PAS, and among NP and PAS sub-groups, including Placenta Accreta (PA), Placenta Increta (PI), and Placenta Percreta (PP). The Multi-gravidity, previous C/S, maternal age, and serum level of PLGF were significantly higher in the PAS group compared to the NP group OR = 42, 8.1, 1.17, and 1.002 (p-value <.05 for all); however, there was no difference regarding serum level of VEGF (p-value >.05). The same differences were seen among NP with PA, PI, and PP sub-groups (p-value <.05 for all, but p-value >.05 for VEGF). Placenta Previa was uniformly distributed across the PAS sub-groups (p-value >.05), also the VEGF and PLGF serum levels did not differ between PAS with Previa and PAS without Previa groups (p-value >.05). A valid cut-off point for PLGF was reported at 63.55. A predictive value of PLGF for the PAS patients is presented enjoying high accuracy and generalisability for the study population.Impact statementWhat is already known on this subject? The Placenta Accreta Spectrum (PAS), in which the placenta grows too deep in the uterine wall, is responsible for maternal-foetal morbidity and mortality worldwide; so, the antenatal diagnosis of PAS is an important key to improve maternal-foetal health. Normal placental implantation requires a fine balance among the levels of angiogenic and anti-angiogenic factors, such as the Placenta Growth Factor (PLGF), the Vascular Endothelial Growth Factor (VEGF), and soluble Fms-like tyrosine kinase-1. However, there is still controversy regarding The PLGF and VEGF level changes in PAS patients.What do the results of this study add? Despite traditional measuring the levels of PLGF and VEGF from the placenta at the time of delivery; in this study including 90 participants (28-34 weeks of gestation) the maternal serum levels of PLGF and VEGF were measured in advance (temporality causation), resulted in presenting a more valid cut-off point for PLGF in PAS group. In addition, the serum level of PLGF was significantly higher in the PAS and PAS sub-groups compared to the Normal Placenta group. Also, the Previa status of PAS patients did not affect the VEGF and PLGF serum levels.What are the implications of these findings for clinical practice and/or further research? PLGF cut-off point derived from the maternal serum level could predict PAS validly and, if used as a screening test in an earlier pregnancy, the maternal-foetal morbidity and mortality would decrease.

Mechanisms linking hypoxia to phosphorylation of insulin-like growth factor binding protein-1 in baboon fetuses with intrauterine growth restriction and in cell culture

Hypoxia increases fetal hepatic insulin-like growth factor binding protein-1 (IGFBP-1) phosphorylation mediated by mechanistic target of rapamycin (mTOR) inhibition. Whether maternal nutrient restriction (MNR) causes fetal hypoxia remains unclear. We used fetal liver from a baboon (Papio sp.) model of intrauterine growth restriction due to MNR (70% global diet of Control) and liver hepatocellular carcinoma (HepG2) cells as a model for human fetal hepatocytes and tested the hypothesis that mTOR-mediated IGFBP-1 hyperphosphorylation in response to hypoxia requires hypoxia-inducible factor-1α (HIF-1α) and regulated in development and DNA-damage responses-1 (REDD-1) signaling. Western blotting (n = 6) and immunohistochemistry (n = 3) using fetal liver indicated greater expression of HIF-1α, REDD-1 as well as erythropoietin and its receptor, and vascular endothelial growth factor at GD120 (GD185 term) in MNR versus Control. Moreover, treatment of HepG2 cells with hypoxia (1% pO₂ ) (n = 3) induced REDD-1, inhibited mTOR complex-1 (mTORC1) activity and increased IGFBP-1 secretion/phosphorylation (Ser101/Ser119/Ser169). HIF-1α inhibition by echinomycin or small interfering RNA silencing prevented the hypoxia-mediated inhibition of mTORC1 and induction of IGFBP-1 secretion/phosphorylation. dimethyloxaloylglycine (DMOG) induced HIF-1α and also REDD-1 expression, inhibited mTORC1 and increased IGFBP-1 secretion/phosphorylation. Induction of HIF-1α (DMOG) and REDD-1 by Compound 3 inhibited mTORC1, increased IGFBP-1 secretion/ phosphorylation and protein kinase PKCα expression. Together, our data demonstrate that HIF-1α induction, increased REDD-1 expression and mTORC1 inhibition represent the mechanistic link between hypoxia and increased IGFBP-1 secretion/phosphorylation. We propose that maternal undernutrition limits fetal oxygen delivery, as demonstrated by increased fetal liver expression of hypoxia-responsive proteins in baboon MNR. These findings have important implications for our understanding of the pathophysiology of restricted fetal growth.

Comparison of Efficiency and Function of Vascular Endothelial Growth Factor Adenovirus Vectors in Endothelial Cells for Gene Therapy of Placental Insufficiency

Severe fetal growth restriction (FGR) affects 1:500 pregnancies, is untreatable and causes serious neonatal morbidity and death. Reduced uterine blood flow (UBF) and lack of bioavailable VEGF due to placental insufficiency is a major cause. Transduction of uterine arteries in normal or FGR sheep and guinea pigs using an adenovirus (Ad) encoding VEGF isoforms A (Ad.VEGF-A₁₆₅) and a FLAG-tagged pre-processed short form D (D^ΔNΔC, Ad.VEGF-D^ΔNΔC-FLAG) increases endothelial nitric oxide expression, enhances relaxation and reduces constriction of the uterine arteries and their branches. UBF and angiogenesis are increased long term, improving fetal growth in utero. For clinical trial development we compared Ad.VEGF vector transduction efficiency and function in endothelial cells (ECs) derived from different species. We aimed to compare the transduction efficiency and function of the pre-clinical study Ad. constructs (Ad.VEGF-A₁₆₅, Ad.VEGF-D^ΔNΔC-FLAG) with the intended clinical trial construct (Ad.VEGF-D^ΔNΔC) where the FLAG tag is removed. We infected ECs from human umbilical vein, pregnant sheep uterine artery, pregnant guinea pig aorta and non-pregnant rabbit aorta, with increasing multiplicity of infection (MOI) for 24 or 48 hours of three Ad.VEGF vectors, compared to control Ad. containing the LacZ gene (Ad.LacZ). VEGF supernatant expression was analysed by ELISA. Functional assessment used tube formation assay and Erk-Akt phosphorylation by ELISA. VEGF expression was higher after Ad.VEGF-D^ΔNΔC-FLAG and Ad.VEGF-D^ΔNΔC transduction compared to Ad.VEGF-A₁₆₅ in all EC types (*p < 0.001). Tube formation was higher in ECs transduced with Ad.VEGF-D^ΔNΔC in all species compared to other constructs (***p < 0.001, *p < 0.05 with rabbit aortic ECs). Phospho-Erk and phospho-Akt assays displayed no differences between the three vector constructs, whose effect was, as in other experiments, higher than Ad.LacZ (***p < 0.001). In conclusion, we observed high transduction efficiency and functional effects of Ad.VEGF-D^ΔNΔC vector with comparability in major pathway activation to constructs used in pre-clinical studies, supporting its use in a clinical trial.

Association of mid-trimester maternal angiogenic biomarkers with small-for-gestational-age infants in an urban Zambian cohort: a nested case-control study

Objective

To investigate whether angiogenic biomarker concentrations differ between women who deliver small‐for‐gestational‐age (SGA) infants (<10th centile birth weight for gestational age) compared with controls, because identifying SGA risk early could improve outcomes.

Methods

This case‐control study compared serum concentrations of angiogenic biomarkers before 24 weeks of pregnancy from 62 women who delivered SGA infants (cases) and 62 control women from an urban Zambian cohort. Odds of delivering an SGA infant were calculated using conditional logistic regression.

Results

Placental growth factor (PlGF), soluble fms‐like tyrosine kinase (sFLT‐1) and soluble endoglin (sEng) in controls were 37.74 pg/mL (interquartile range [IQR] 23.12–63.15), 2525.18 pg/mL (IQR 1502.21–4265.54) and 2408.18 pg/mL (IQR 1854.87–3017.94), respectively. SGA cases had higher PlGF (40.50 pg/mL, IQR 22.81–67.94) and sFLT‐1 (2613.06 pg/mL, IQR 1720.58–3722.50), and lower sEng (2038.06 pg/mL, IQR 1445.25–3372.26). Participants with sEng concentration below and concomitant sFLT‐1 concentration above their respective thresholds (n = 40) had five‐fold higher odds of SGA (adjusted odds ratio 4.77, 95% confidence interval 1.61–14.1; P = 0.005).

Conclusion

Biomarker concentrations were similar between cases and controls. Participants with concomitant low sEng and high sFLT‐1 had the highest odds of SGA, suggesting that a combination of biomarkers may better for predicting SGA than single biomarkers.

Prediction of SGA risk using the interaction of multiple angiogenic biomarkers may perform better than using a single angiogenic biomarker concentration before 24 weeks gestation.

Physiopathology of late-onset fetal growth restriction

Fetal growth restriction (FGR) is defined as the inability of the fetus to reach its potential for genetic determination. FGR can have several causes, including genetic syndromes, chromosomal diseases, and infections; however, a vast majority of cases are probably attributed to impaired uterine and placental circulation. The relationships between abnormal placental development and FGR are complex, and studies are generally few, presenting confounding factors. Damage to the uteroplacental circulation associated with vasculogenesis and villus angiogenesis dysfunction are the main factors involved in subsequent FGR. The main receptors involved in FGR include hypoxia-inducible factor (HIF 1, 2, and 3), vascular endothelial growth factor (VEGF), placental growth factor (PlGF), vascular endothelial growth factor C (VEGF-C), soluble Flt-1, soluble endoglin (Seng), angiopoietin-1 and -2 (Ang-1 and Ang-2), tyrosine kinase receptor 1 (Flt-1), tyrosine kinase receptor 2 (Flt-2), vascular endothelial growth factor receptor (VEGFR) 1, 2 and 3, kinase domain receptor (KDR), and vascular endothelial growth factor receptor A (VEGFR-A). Furthermore, failure in trophoblastic invasion and remodeling of spiral arteries has been associated with FGR owing to poor placental perfusion. There are several possible causes for poor remodeling of spiral arteries, which probably vary on a case-to-case basis. Changes in the placental form, macroscopic and microscopic vascular lesions, inflammation, and genetic changes are also related to FGR. Based on gestational age at diagnosis, FGR can be classified as early- (˂32 weeks) and late-onset (≥32 weeks). Moreover, there exist several theories regarding possible pathophysiological differences between early- and late-onset FGR, with some postulating that it the same disease but at different stages or severity. Another hypothesis suggests that the change in the trophoblastic invasion of spiral arteries would be milder. In this article, we address the main mechanisms described in the pathophysiology of FGR and, later, the specific findings in late-onset FGR.

Ultrasonographic findings of the corpus luteum and the gravid uterus during heat stress in dairy cattle

The objectives of this study were to assess alterations in, echogenic appearance, size and blood flow in the corpus luteum, the placentomes and the blood flow in umbilical and uterine arteries that heat stress can cause in cooled pregnant dairy cows. Pregnant cows were allocated in two groups and the gravid uteri, along with the ipsilateral corpora lutea were examined during the winter (group W, n = 9) or the summer (group S, n = 10). The grey-scale ultrasound and colour flow imaging of the corpus luteum and placentome were performed. In addition, the umbilical and uterine artery diameters and haemodynamic parameters in the vessels were calculated. At the time of ultrasonographic examination, cortisol concentrations were higher, and progesterone levels tended to be lower in group S compared to group W. The grey-scale ultrasound evaluation of corpora lutea and placentomes was lower in group S compared to group W. The diameter of umbilical artery and the blood volume in the vessel were less in group S than in group W. We infer that heat stress affects foetal blood supply and possibly the structure of placentomes and corpora lutea, but it differently affects the blood flow characteristics in the umbilical and uterine arteries.

Recurrent Cesarean scar pregnancy: case series and literature review

OBJECTIVES

To determine the rate of recurrent Cesarean scar pregnancy (CSP) in our clinical practices and to evaluate whether the mode of treatment of a CSP is associated with the risk of recurrent CSP, as well as to review the published literature on recurrent CSP.

METHODS

We performed a retrospective search of our six obstetric and gynecological departmental ultrasound databases for all CSPs and recurrent CSPs between 2010 and 2019. We extracted various data, including number of CSPs with follow-up, number of cases attempting and number achieving pregnancy following treatment of CSP and number of recurrent CSPs, as well as details of the treatment of the original CSP. After analyzing the clinical data, we evaluated whether the mode of treatment terminating the previous CSP was associated with the risk of recurrent CSP. We also performed a PubMed search for: 'recurrent Cesarean scar pregnancy' and 'recurrent Cesarean scar ectopic pregnancy'. Articles were reviewed for year of publication, and extraction and analysis of the same data as those obtained from our departmental databases were performed.

RESULTS

Our database search identified 252 cases of CSP. The overall rate of clinical follow-up ranged between 71.4% and 100%, according to treatment site (mean, 90.9%). Among these, 105 women had another pregnancy after treatment of the previous CSP. Of these, 36 (34.3%) pregnancies were recurrent CSP, with 27 women having a single recurrence and three women having multiple recurrences, one with two, one with three and one with four. We did not find any particular single or combination treatment mode terminating the previous CSP to be associated with recurrent CSP. The literature search identified 17 articles that yielded sufficient information for us to evaluate their reported prevalence of recurrent CSP. These reported 1743 primary diagnoses of CSP, of which 944 had reliable follow-up. Data were available for 489 cases that attempted to conceive again after treatment of a previous CSP, and on the 327 pregnancies achieved. Of these, 67 (20.5%) were recurrent CSP.

CONCLUSIONS

On the basis of our pooled clinical data and review of the literature, recurrent CSP is apparently more common than was previously assumed based upon mostly single-case reports or series with few cases. This should be borne in mind when counseling patients undergoing treatment for CSP regarding their risk of recurrence. We found no obvious causal relationship or association between the type of treatment of the previous CSP and recurrence of CSP. Patients who become pregnant after treatment of a CSP should be encouraged to have an early (5-7-week) first-trimester transvaginal scan to determine the location of the gestation. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

MiR-590-3p and its targets VEGF, PIGF, and MMP9 in early, middle, and late pregnancy: their longitudinal changes and correlations with risk of fetal growth restriction

AIMS

The term "fetal growth restriction (FGR)" is commonly used to describe fetuses with an estimated fetal weight that is less than 10th percentile for gestational age. This study aimed to investigate the longitudinal change of microRNA-590-3p (miR-590-3p), vascular endothelial growth factor (VEGF), placental growth factor (PIGF), and matrix metalloproteinase (MMP)9 expressions in early, middle, and late pregnancy, and their correlations with the fetal growth restriction (FGR) risk.

METHODS

Totally, 970 pregnant women in early pregnancy were enrolled, and their plasma samples were, respectively, acquired in early pregnancy (at 10th or 11th week of gestational age), middle pregnancy (at 20th or 21st week of gestational age), and late pregnancy (at 33th or 34th week of gestational age) for miR-590-3p, VEGF, PIGF, and MMP9 determinations.

RESULTS

MiR-590-3p underwent a growing trend, but VEGF, PIGF, and MMP9 experienced declined trend along with pregnancy (all P < 0.001). Furthermore, the negative association of miR-590-3p with VEGF, PIGF, and MMP9 became stronger along with the pregnancy. Besides, miR-590-3p expression in middle and late pregnancy was higher, but VEGF, PIGF, and MMP9 expressions in middle and late pregnancy were lower in women affected by FGR compared to normal pregnant women (all P < 0.001). In addition, miR-590-3p, VEGF, PIGF, and MMP9 expression in middle and late pregnancy were of good value in predicting FGR risk.

CONCLUSIONS

miR-590-3p exhibits a growing trend during pregnancy, and its expression in middle and late pregnancy is associated with increased FGR risk via interaction with VEGF, PIGF, and MMP9.

Let's Talk about Placental Sex, Baby: Understanding Mechanisms That Drive Female- and Male-Specific Fetal Growth and Developmental Outcomes

It is well understood that sex differences exist between females and males even before they are born. These sex-dependent differences may contribute to altered growth and developmental outcomes for the fetus. Based on our initial observations in the human placenta, we hypothesised that the male prioritises growth pathways in order to maximise growth through to adulthood, thereby ensuring the greatest chance of reproductive success. However, this male-specific “evolutionary advantage” likely contributes to males being less adaptable to shifts in the in-utero environment, which then places them at a greater risk for intrauterine morbidities or mortality. Comparatively, females are more adaptable to changes in the in-utero environment at the cost of growth, which may reduce their risk of poor perinatal outcomes. The mechanisms that drive these sex-specific adaptations to a change in the in-utero environment remain unclear, but an increasing body of evidence within the field of developmental biology would suggest that alterations to placental function, as well as the feto-placental hormonal milieu, is an important contributing factor. Herein, we have addressed the current knowledge regarding sex-specific intrauterine growth differences and have examined how certain pregnancy complications may alter these female- and male-specific adaptations.

Disorders of placental villous maturation are present in one-third of cases with spontaneous preterm labor

OBJECTIVES

Spontaneous preterm labor is an obstetrical syndrome accounting for approximately 65-70% of preterm births, the latter being the most frequent cause of neonatal death and the second most frequent cause of death in children less than five years of age worldwide. The purpose of this study was to determine and compare to uncomplicated pregnancies (1) the frequency of placental disorders of villous maturation in spontaneous preterm labor; (2) the frequency of other placental morphologic characteristics associated with the preterm labor syndrome; and (3) the distribution of these lesions according to gestational age at delivery and their severity.

METHODS

A case-control study of singleton pregnant women was conducted that included (1) uncomplicated pregnancies (controls, n=944) and (2) pregnancies with spontaneous preterm labor (cases, n=438). All placentas underwent histopathologic examination. Patients with chronic maternal diseases (e.g., chronic hypertension, diabetes mellitus, renal disease, thyroid disease, asthma, autoimmune disease, and coagulopathies), fetal malformations, chromosomal abnormalities, multifetal gestation, preeclampsia, eclampsia, preterm prelabor rupture of the fetal membranes, gestational hypertension, gestational diabetes mellitus, and HELLP (hemolysis, elevated liver enzymes and low platelet count) syndrome were excluded from the study.

RESULTS

Compared to the controls, the most prevalent placental lesions among the cases were the disorders of villous maturation (31.8% [106/333] including delayed villous maturation 18.6% [62/333] vs. 1.4% [6/442], q<0.0001, prevalence ratio 13.7; and accelerated villous maturation 13.2% [44/333] vs. 0% [0/442], q<0.001). Other lesions in decreasing order of prevalence included hypercapillarized villi (15.6% [68/435] vs. 3.5% [33/938], q<0.001, prevalence ratio 4.4); nucleated red blood cells (1.1% [5/437] vs. 0% [0/938], q<0.01); chronic inflammatory lesions (47.9% [210/438] vs. 29.9% [282/944], q<0.0001, prevalence ratio 1.6); fetal inflammatory response (30.1% [132/438] vs. 23.2% [219/944], q<0.05, prevalence ratio 1.3); maternal inflammatory response (45.5% [195/438] vs. 36.1% [341/944], q<0.01, prevalence ratio 1.2); and maternal vascular malperfusion (44.5% [195/438] vs. 35.7% [337/944], q<0.01, prevalence ratio 1.2). Accelerated villous maturation did not show gestational age-dependent association with any other placental lesion while delayed villous maturation showed a gestational age-dependent association with acute placental inflammation (q-value=0.005).

CONCLUSIONS

Disorders of villous maturation are present in nearly one-third of the cases of spontaneous preterm labor.

The role of mediating factors involved in angiogenesis during implantation

Angiogenesis is a critical component of normal implantation and placentation and underlines the importance of vascularization in early pregnancy. Differentiated expression of angiogenesis factors in different decision tissues during different stages of implantation, indicates their involvement in the regulation of vascular remodeling and angiogenesis. Disorders in vascular development may play a role in the pathogenesis of recurrent abortions. The success of implantation, placentation and subsequent pregnancy evolution requires coordination of vascular development and adaptations at both sides of the maternal–fetal interface. The human implantation process is a continuous process, which begins with the apposition and attachment of the blastocyst to the apical surface of the luminal endometrial epithelium and continues throughout the first trimester of pregnancy until the extravillous trophoblast invades and remodels maternal vascularization. Numerous regulatory molecules play functional roles in many processes, including preparation of the endometrial stroma (decidualization), epithelium for implantation, control of trophoblastic adhesion and invasion. These regulatory molecules include cytokines, chemokines, and proteases, many of which are expressed by different cell types, having slightly different functions as the implant progresses

Physical activity differentially regulates VEGF, PlGF, and their receptors in the human placenta

Physical activity (PA) has beneficial effects on the function of many organs by modulating their vascular development. Regular PA during pregnancy is associated with favorable short‐ and long‐term outcomes for both mother and fetus. During pregnancy, appropriate vascularization of the placenta is crucial for adequate maternal–fetal nutrient and gas exchange. How PA modulates angiogenic factors, VEGF, and its receptors in the human placenta, is as of yet, unknown. We objectively measured the PA of women at 24–28 and 34–38 weeks of gestation. Participants were considered “active” if they had met or exceeded 150 min of moderate‐intensity PA per week during their 2nd trimester. Term placenta tissues were collected from active (n = 23) or inactive (n = 22) women immediately after delivery. We examined the expression of the angiogenic factors VEGF, PlGF, VEGFR‐1, and VEGFR‐2 in the placenta. Western blot analysis showed VEGF and its receptor, VEGFR‐1 was significantly (p < 0.05) higher both at the protein and mRNA levels in placenta from physically active compared to inactive women. No difference in VEGFR‐2 was observed. Furthermore, immunohistochemistry showed differential staining patterns of VEGF and its receptors in placental endothelial, stromal, and trophoblast cells and in the syncytial brush border. In comparison, PlGF expression did not differ either at the protein or mRNA level in the placenta from physically active or inactive women. The expression and localization pattern of VEGF and its receptors suggest that PA during pregnancy may support a pro‐angiogenic milieu to the placental vascular network.

Study of the Development of Placental Microvascularity by Doppler SMI (Superb Microvascular Imaging): A Reality Today

Our objective was to evaluate the development of placental vascularization in normal gestation by using Doppler superb microvascular imaging (SMI). The fetal and maternal parameters of 20 pregnant women without pathology were evaluated at weeks 12, 16, 20-22, 24-26, 28-30, 32-34, 36-38 and 40-42. Doppler SMI was used to evaluate the placental vascularization (pulsatile index and peak systolic velocity) of the primary, secondary and tertiary (third) villi, and qualitative placental descriptions and anatomic-pathologic studies of these placentas were performed. The number of cotyledons identified by Doppler SMI increased from two between weeks 16 and 18 to 24 between weeks 28 and 38. The secondary and tertiary villi began developing at 20 wk of gestation. The pulsatile index of the primary villi remained constant (0.8-0.9 in all pregnancies). The pulsatile index of the secondary and tertiary villi increased from 1.1 to 1.53 and from 1.4 to 1.68, respectively. The peak systolic velocity underwent a significant increase throughout gestation in the secondary and tertiary villi (9.2 to 34.9 cm/s and 7.5 to 52.9 cm/s, respectively). We evaluated the development of placental microvascularization using Doppler SMI in pregnancies without pathology and describe normal placental Doppler SMI findings.

Expression of p57KIP2 reduces growth and invasion, and induces syncytialization in a human placental choriocarcinoma cell line, BeWo

INTRODUCTION

Syncytiotrophoblasts are the major components of the human placenta involved in fetal maternal exchange and hormone secretion. The syncytiotrophoblasts arise from the fusion of villous cytotrophoblasts. The cell cycle suppressor p57^KIP2 is known to be an essential molecule for proper trophoblast differentiation during placental formation.

METHODS

We generated p57^KIP2-expressing BeWo transfectant cells. Proliferation assay and matrigel invasion assay were used to characterize p57^KIP2-expressing BeWo transfectant cells. To reveal the role of p57^KIP2 in syncytialization, we proceeded syncytium formation analysis and qRT-PCR for detection of the expression levels Syncytin-1, Syncytin-2 and their receptors.

RESULTS

The human choriocarcinoma cell line, BeWo has undetectable levels of p57^KIP2 expression. Expression of p57^KIP2 reduced cell proliferation rate and extracellular matrix invasion activity. p57^KIP2 expressing cells displayed multinucleated cells associated with syncytiotrophoblast differentiation. In the syncytialization event, p57^KIP2 was found to potentiate forskolin-induced upregulation of Syncytin-2 in a cAMP-independent manner.

DISCUSSION

These results indicate that the expression of p57^KIP2 may act on the proliferation/invasion inhibitory factor and enhance the expression of Syncytin-2, which are associated with syncytialization in cytotrophoblasts.

miR-129-5p and miR-130a-3p Regulate VEGFR-2 Expression in Sensory and Motor Neurons during Development

The wide-ranging influence of vascular endothelial growth factor (VEGF) within the central (CNS) and peripheral nervous system (PNS), for example through effects on axonal growth or neuronal cell survival, is mainly mediated by VEGF receptor 2 (VEGFR-2). However, the regulation of VEGFR-2 expression during development is not yet well understood. As microRNAs are considered to be key players during neuronal maturation and regenerative processes, we identified the two microRNAs (miRNAs)-miR-129-5p and miR-130a-3p-that may have an impact on VEGFR-2 expression in young and mature sensory and lower motor neurons. The expression level of VEGFR-2 was analyzed by using in situ hybridization, RT-qPCR, Western blot, and immunohistochemistry in developing rats. microRNAs were validated within the spinal cord and dorsal root ganglia. To unveil the molecular impact of our candidate microRNAs, dissociated cell cultures of sensory and lower motor neurons were transfected with mimics and inhibitors. We depicted age-dependent VEGFR-2 expression in sensory and lower motor neurons. In detail, in lower motor neurons, VEGFR-2 expression was significantly reduced during maturation, in conjunction with an increased level of miR-129-5p. In sensory dorsal root ganglia, VEGFR-2 expression increased during maturation and was accompanied by an overexpression of miR-130a-3p. In a second step, the functional significance of these microRNAs with respect to VEGFR-2 expression was proven. Whereas miR-129-5p seems to decrease VEGFR-2 expression in a direct manner in the CNS, miR-130a-3p might indirectly control VEGFR-2 expression in the PNS. A detailed understanding of genetic VEGFR-2 expression control might promote new strategies for the treatment of severe neurological diseases like ischemia or peripheral nerve injury.

The impact of maternal asthma during pregnancy on offspring retinal microvascular structure and its relationship to placental growth factor production in utero

Asthma is a common chronic disease in pregnancy that affects placental function and fetal growth and associated with cardio-metabolic disorders in the offspring but the mechanisms are unknown. This study explored whether maternal asthma in pregnancy is associated with the development of offspring microvascular structure and whether it was related to biomarkers of angiogenesis in utero. Children aged 4 to 6 years, born to either asthmatic mothers (n = 38) or healthy controls (n = 25), had their retinal microvascular structure examined. Maternal plasma PlGF concentrations at 18 and 36 weeks' gestation were measured. There was a significant global difference in all retinal microvascular measures between children of asthmatic mothers relative to controls and increased retinal venular tortuosity in children born to asthmatic mothers (7.1 (95% CI 0.7-13.5); P = .031). A rise in plasma PlGF from 18 to 36 weeks' gestation was observed in the control population which was significantly lower in the asthma group by 190.9 pg/mL. PlGF concentrations were correlated with microvascular structure including arteriolar branching and venular tortuosity. These exploratory findings indicate that exposure to maternal asthma during pregnancy is associated with persistent changes in microvascular structure in childhood that may be driven by alterations to angiogenic mechanisms in utero.

Melatonin: An atypical hormone with major functions in the regulation of angiogenesis

Melatonin (N-acetyl-5-methoxytryptamine), a pleotropic molecule with a wide distribution, has received considerable attention in recent years, mostly because of its various major effects on tissues or cells since it has both receptor-dependent and receptor-independent actions over a wide range of concentrations. These biological and physiological functions of melatonin include regulation of circadian rhythms by modulating the expression of core oscillator genes, scavenging the reactive oxygen species and reactive nitrogen species, modulating the immune system and inflammatory response, and exerting cytoprotective and antiapoptotic effects. Given the multiple critical roles of melatonin, dysregulation of its production or any disruption in signaling through its receptors may have contributed in the development of a wide range of disorders including type 2 diabetes, aging, immune-mediated diseases, hypertension, and cancer. Herein, we focus on the modulatory effects of melatonin on angiogenesis and its implications as a therapeutic strategy in cancer and related diseases.

Platelet Indices and CXCL12 Levels in Patients with Intrauterine Growth Restriction

Background

Intrauterine growth restriction (IUGR) is a multifactorial condition, and the precise mechanism is still unknown. In the current study, we aimed to determine the relationship between the platelet (PLT) indices and CXC12 levels in patients with IUGR.

Patients and Materials

In this study, 36 patients with IUGR and 36 healthy pregnant mothers were enrolled as the case and control groups, respectively. Gestational age for both groups was between 24 and 40 years. Blood samples were taken, and platelet indices were examined by a full-diff cell counter. Serum levels of CXCL12 were measured by ELISA, and the data were analyzed using an independent Student's t-test.

Results

In this study, we observed that the mean value of PLT count (154.3 ± 50 vs 236 ± 36) and plateletcrit (0.124 ± 0.038 vs 0.178 ± 0.021) were significantly lower in the case than the control group. In contrast, the mean platelet volume (7.94 ± 0.55 vs 7.62 ± 0.53) and platelet distribution width (17.57 ± 0.7 vs 16.96 ± 0.59) were significantly higher in the case than the control group. More importantly, we found that the serum levels of CXCL12 were significantly higher (5.3 ng/mL± 3.1 vs 2.8 ± 1.6) in the patients compared to the pregnancy controls.

Conclusion

Our data show that platelet indices are changed in IUGR, and the levels of circulating CXCL12 are increased in patients with IUGR. These findings provide a base for further studies to better defining the pathophysiology of IUGR.

[Role of the renin-angiotensin system in pregnancy and preeclampsia]

The renin-angiotensin system (ARS) is a hormonal cascade that regulates blood pressure, electrolytes and water balance. AngiotensinII (AII) exerts its effects through the AT1 and AT2 receptors. AT1 is found in the syncytiotrophoblast, AT2 predominates during foetal development and its stimulation inhibits cell growth, increases apoptosis, causes vasodilation and regulates the development of foetal tissue. There is also an SRA in the placenta. The local generation of AII is responsible for the activation of AT1 receptors in the trophoblast. In normal pregnancy, concomitantly with reduction of blood pressure the circulating RAS increases, but blood pressure does not rise due to AII refractoriness, which does not occur in preeclampsia. We review the role of the SRA in normal pregnancy and preeclampsia.

Equine hydrallantois is associated with impaired angiogenesis in the placenta

INTRODUCTION

Hydrallantois is the excessive accumulation of fluid in the allantoic cavities during the last trimester of pregnancy, leading to abdominal wall hernias, cardiovascular shock, abortion, and dystocia. It has been postulated that hydrallantois is associated with structural and/or functional changes in the chorioallantoic membrane. In the present study, we hypothesized that angiogenesis is impaired in the hydrallantoic placenta.

METHOD

Capillary density in the hydrallantoic placenta was evaluated in the chorioallantois via immunohistochemistry for Von Willebrand Factor. Moreover, the expression of angiogenic genes was compared between equine hydrallantois and age-matched, normal placentas.

RESULTS

In the hydrallantoic samples, edema was the main pathological finding. The capillary density was significantly lower in the hydrallantoic samples than in normal placentas. The reduction in the number of vessels was associated with abnormal expression of a subset of angiogenic and hypoxia-associated genes including VEGF, VEGFR1, VEGFR2, ANGPT1, eNOS and HIF1A. We believe that the capillary density and the abnormal expression of angiogenic genes leads to tissue hypoxia (high expression of HIF1A) and edema. Finally, we identified a lower expression of genes associated with steroidogenic enzyme (CYP19A1) and estrogen receptor signaling (ESR2) in the hydrallantoic placenta.

DISCUSSION

Based on the presented data, we believe that formation of edema is due to disrupted vascular development (low number of capillaries) and hypoxia in the hydrallantoic placenta. The edema leads to further hypoxia and consequently, causes an increase in vessel permeability which leads to a gradual increase in interstitial fluid accumulation, resulting in an insufficient transplacental exchange rate and accumulation of fluid in the allantoic cavity.

Placental growth factor in beta cells plays an essential role in gestational beta-cell growth

OBJECTIVE

Pancreatic beta cells proliferate in response to metabolic requirements during pregnancy, while failure of this response may cause gestational diabetes. A member of the vascular endothelial growth factor family, placental growth factor (PlGF), typically plays a role in metabolic disorder and pathological circumstance. The expression and function of PlGF in the endocrine pancreas have not been reported and are addressed in the current study.

RESEARCH DESIGN AND METHODS

PlGF levels in beta cells were determined by immunostaining or ELISA in purified beta cells in non-pregnant and pregnant adult mice. An adeno-associated virus (AAV) serotype 8 carrying a shRNA for PlGF under the control of a rat insulin promoter (AAV-rat insulin promoter (RIP)-short hairpin small interfering RNA for PlGF (shPlGF)) was prepared and infused into mouse pancreas through the pancreatic duct to specifically knock down PlGF in beta cells, and its effects on beta-cell growth were determined by beta-cell proliferation, beta-cell mass and insulin release. A macrophage-depleting reagent, clodronate, was coapplied into AAV-treated mice to study crosstalk between beta cells and macrophages.

RESULTS

PlGF is exclusively produced by beta cells in the adult mouse pancreas. Moreover, PlGF expression in beta cells was significantly increased during pregnancy. Intraductal infusion of AAV-RIP-shPlGF specifically knocked down PlGF in beta cells, resulting in compromised beta-cell proliferation, reduced growth in beta-cell mass and impaired glucose tolerance during pregnancy. Mechanistically, PlGF depletion in beta cells reduced islet infiltration of trophic macrophages, which appeared to be essential for gestational beta-cell growth.

CONCLUSIONS

Our study suggests that increased expression of PlGF in beta cells may trigger gestational beta-cell growth through recruited macrophages.