Reduced angiogenic factor expression in intrauterine fetal growth restriction using semiquantitative immunohistochemistry and digital image analysis

Mtnr1b deletion disrupts placental angiogenesis through the VEGF signaling pathway leading to fetal growth restriction

The placenta, as a "transit station" between mother and fetus, has functions delivering nutrients, excreting metabolic wastes and secreting hormones. A healthy placenta is essential for fetal growth and development while the melatonergic system seems to play a critical physiological role in this organ since melatonin, its synthetic enzymes and receptors are present in the placenta. In current study, Mtnr1a and Mtnr1b knockout mice were constructed to explore the potential roles of melatonergic system played on the placental function and intrauterine growth retardation (IUGR). The result showed that Mtnr1a knockout had little effect on placental function while Mtnr1b knockout reduced placental efficiency and increased IUGR. Considering the extremely high incidence of IURG in sows, the pregnant sows were treated with melatonin. This treatment reduced the incidence of IUGR. All the evidence suggests that the intact melatonergic system in placenta is required for its function. Mechanistical studies uncovered that Mtnr1b knockout increased placental oxidative stress and apoptosis but reduced the angiogenesis. The RNA sequencing combined with histochemistry study identified the reduced angiogenesis and placental vascular density in Mtnr1b knockout mice. These alterations were mediated by the disrupted STAT3/VEGFR2/PI3K/AKT pathway, i.e., Mtnr1b knockout reduced the phosphorylation of STAT3 which is the promotor of VEGFR2. The downregulated VEGFR2 and its downstream elements of PI3K and AKT expressions, then, jeopardizes the angiogenesis and placental development.

Do small for gestational age fetuses have placental pathologies?

PURPOSE

Although small for gestational age (SGA) does not cause adverse perinatal outcomes, the placental pathology for fetal growth restricted (FGR) and SGA fetuses is still unknown. The aim of this study is to evaluate the differences between placentas of early onset FGR, late onset FGR, SGA, and appropriate for gestational age (AGA) pregnancies in the manner of microvasculature and expression of anti-angiogenic PEDF factor and CD68.

METHODS

The study included four groups (early onset FGR, late onset FGR, SGA and AGA). Placental samples were obtained just after labor in all of the groups. Degenerative criteria were investigated with Hematoxylin-eosin staining. Immunohistochemical evaluation with H score and m RNA levels of Cluster of differentiation 68 (CD68) and pigment epithelium derived factor (PEDF) were performed for each group.

RESULTS

The highest levels of degeneration were detected in the early onset FGR group. In means of degeneration SGA placentas were found to be worse than the AGA placentas. The intensity of PEDF and CD68 were significant in early FGR, the late FGR and SGA groups compared to the AGA group (p < 0.001). The mRNA level results of the PEDF and CD68 were also parallel to the immunostaining results.

CONCLUSION

Although SGA fetuses are considered constitutionally small, the SGA placentas also demonstrated signs of degeneration similar to the FGR placentas. These degenerative signs were not seen among the AGA placentas.

Preterm rat survival is enhanced by gestational environmental enrichment

Throughout the last decade, the estimated global human preterm birth rate was 10.6 %, with higher rates in Asia, South America, and Africa. Preterm individuals, even in adulthood, are more likely to develop cardiorespiratory, renal, and metabolic disorders. On the other hand, when experimental animals are housed in an enriched environment during gestation, the development of the progeny in utero is accelerated, compared to standard housing conditions. By terminating gestation one and a half days before parturition, we investigated whether environmental enrichment restricted to gestation may have an impact on progeny survival. Our results demonstrate that the gestational enriched environment tripled the rat´s offspring survival, which was associated with decreased expression of anxiety-like behaviors in the pregnant mother. Sex of the offspring was not a factor in determining survival. We discuss the effect of increased secretion of various trophic factors and hormones induced by the enriched environment on progeny survival.

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.

Application of Digital Imaging and Artificial Intelligence to Pathology of the Placenta

Digital imaging, including the use of artificial intelligence, has been increasingly applied to investigate the placenta and its related pathology. However, there has been no comprehensive review of this body of work to date. The aim of this study was to therefore review the literature regarding digital pathology of the placenta. A systematic literature search was conducted in several electronic databases. Studies involving the application of digital imaging and artificial intelligence techniques to human placental samples were retrieved and analyzed. Relevant articles were categorized by digital image technique and their relevance to studying normal and diseased placenta. Of 2008 retrieved articles, 279 were included. Digital imaging research related to the placenta was often coupled with immunohistochemistry, confocal microscopy, 3D reconstruction, and/or deep learning algorithms. By significantly increasing pathologists' ability to recognize potentially prognostic relevant features and by lessening inter-observer variability, published data overall indicate that the application of digital pathology to placental and perinatal diseases, along with clinical and radiology correlation, has great potential to improve fetal and maternal health care including the selection of targeted therapy in high-risk pregnancy.

FEATURES OF THE FUNCTIONAL MORPHOLOGY OF THE FULL-TERM PLACENTA IN WOMEN WITH THREATENED ABORTION WITH BLEEDING IN THE FIRST TRIMESTER OF GESTATION

OBJECTIVE

The aim: To examine the morphology regarding the term placentas in pregnancies with threatened abortion with bleeding in the first trimester.

PATIENTS AND METHODS

Materials and methods: 118 term placentas were selected, of which 40 placentas with the physiological course of pregnancy. 78 placentas were from women with threatened abortion with bleeding in the first trimester, of which 37 patients received hormonal therapy (group I), 41 women were prescribed symptomatic therapy (group II). Placentas were investigatedaccording to the protocol, which includes organometric, macroscopic and microscopic studies.

RESULTS

Results: In the placentas of group II is a significant increase of the area of terminal villi compared due to the stroma against the background of a deficit of fetal capillaries. In group I have revealed that the specific weight of the vascular bed of the terminal villi was 1.5 times higher compared to the control (Р=0.031) and 2.7 times higher than the group II (Р=0.022) and dominates the share of the stroma. The weight of the epithelium of the terminal villi in all groups is approximately the same (Р=0.042), but the ratio of the epithelium to the stroma is higher in the group I (0.63) than in the control (0.43).

CONCLUSION

Conclusions: In women with a pathological course of the first trimester of pregnancy the compensatory mechanisms in full-term placentas are morphologically represented by an increase in the number of terminal villi, syncytio-capillary membranes, intensification of angiogenesis. In the placentas of women who received hormonal therapy adaptive reactions are most effective and able to compensate for the gestational immaturity of the chorion.

Dexamethasone-induced intrauterine growth restriction modulates expression of placental vascular growth factors and fetal and placental growth

Prenatal exposure to glucocorticoids (GC) is a central topic of interest in medicine since GCs are essential for the maturation of fetal organs and intrauterine growth. Synthetic glucocorticoids, which are used in obstetric practice, exert beneficial effects on the fetus, but have also been reported to lead to intrauterine growth retardation (IUGR). In this study, a model of growth restriction in mice was established through maternal administration of dexamethasone during late gestation. We hypothesised that GC overexposure may adversely affect placental angiogenesis and fetal and placental growth. Female BALB/c mice were randomly assigned to control or dexamethasone treatment, either left to give birth or euthanised on days 15, 16, 17 and 18 of gestation followed by collection of maternal and fetal tissue. The IUGR rate increased to 100% in the dexamethasone group (8 mg/kg body weight on gestational days 14 and 15) and pups had clinical features of symmetrical IUGR at birth. Dexamethasone administration significantly decreased maternal body weight gain and serum corticosterone levels. Moreover, prenatal dexamethasone treatment not only induced fetal growth retardation but also decreased placental weight. In IUGR placentas, VEGFA protein levels and mRNA expression of VEGF receptors were reduced and NOS activity was lower. Maternal dexamethasone administration also reduced placental expression of the GC receptor, αGR. We demonstrated that maternal dexamethasone administration causes fetal and placental growth restriction. Furthermore, we propose that the growth retardation induced by prenatal GC overexposure may be caused, at least partially, by an altered placental angiogenic profile.

Lipid profiling in maternal and fetal circulations in preeclampsia and fetal growth restriction-a prospective case control observational study

Background

While many risk factors for preeclampsia, such as increased body mass index, advanced maternal age, chronic hypertension, diabetes, are now established in clinical practice, maternal lipid profile has not been included in the risk assessment for preeclampsia. We aim to characterize the serum levels of Total Cholesterol (TC), High density lipoprotein (HDL), Low density lipoprotein (LDL), Triglycerides (TG), Apolipoprotein A1, Apolipoprotein B and their ratios TC/HDL and ApoB/ApoA1 in the maternal and fetal circulations of normal pregnancy, preeclampsia (PE), fetal growth restriction (FGR) and PE + FGR.

Methods

A prospective cross-sectional case control study was conducted measuring maternal and fetal lipid levels by enzymatic analysis and immune-turbidimetric enzymatic assays. FGR was defined by elevated umbilical artery Doppler resistance in association with estimated fetal weight < 10%. Kruskal Wallis non-parametric analysis of variance was used to test for homogeneity across the clinical groups for each of the variables, Mann-Whitney tests for pairwise comparisons and Spearman rank correlation were used to quantify gestational age-related changes.

Results

(1) TG levels were elevated in maternal PE and cord blood PE + FGR groups compared to normal pregnancies. (2) A statistically significant elevation of fetal ApoB levels was observed in PE, FGR and PE + FGR compared to normal pregnancies. Apolipoprotein levels A1 and B were not different between maternal groups. (3) TC, HDL, LDL and TC/HDL levels did not show any significant gestational variation or between clinical groups in the maternal or fetal circulation.

Conclusions

Elevation in maternal TG levels may have a role in the pathogenesis of PE. The implications of elevated maternal and fetal TG levels and elevated fetal Apolipoprotein B levels deserves further exploration of their role in long term cardiovascular risk in the mother as well as the offspring.

Urinary placental growth factor in preeclampsia and fetal growth restriction: An alternative to circulating biomarkers?

AIM

To correlate plasma and urinary soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PIGF) in preeclampsia (PE) and fetal growth restriction (FGR) and assess the performance in detecting established disease.

METHODS

A cross-sectional case-control study recruited 26-40 weeks gestation pregnancies into four clinical groups: normal pregnancy, PE, PE + FGR, and FGR. enzyme-linked immunosorbent assay (ELISA) measurements of urinary and plasma sFlt-1 and PlGF levels were performed. Urinary levels of sFlt-1 and PIGF were normalized to creatinine. Spearman's rank correlation was used to assess the association between plasma and urinary levels of sFlt-1 and PIGF, and receiver operating characteristic graphs were used to quantify the performance of each individual marker and their ratios in predicting normal versus pathological pregnancies affected by preeclampsia and/or FGR.

RESULTS

There was a significant correlation between plasma PlGF and urinary PlGF (r = 0.718, P < 0.001) in all groups. In the pathological groups, plasma sFlt-1 and urinary sFlt-1 as well as plasma sFlt-1: PIGF ratio and urinary sFlt-1: PlGF ratio were higher, but plasma PIGF and urinary PlGF were lower when compared to normal pregnancy. Plasma PIGF and plasma sFlt-1: PlGF ratio was comparable in performance to urinary PlGF and urinary sFlt-1: PIGF ratio for the diagnosis of preeclampsia and/or FGR.

CONCLUSION

Urinary PIGF can be used as an alternative to circulating biomarkers in preeclampsia and FGR. Plasma sFlt-1, PlGF and sFlt-1: PlGF ratio as well as urinary PIGF and sFlt-1: PlGF ratio can be used to differentiate between normal pregnancy and pregnancies complicated by preeclampsia and FGR.

Impaired Progesterone-Responsiveness of CD11c+ Dendritic Cells Affects the Generation of CD4+ Regulatory T Cells and Is Associated With Intrauterine Growth Restriction in Mice

Up to 10% of pregnancies in Western societies are affected by intrauterine growth restriction (IUGR). IUGR reduces short-term neonatal survival and impairs long-term health of the children. To date, the molecular mechanisms involved in the pathogenesis of IUGR are largely unknown, but the failure to mount an adequate endocrine and immune response during pregnancy has been proposed to facilitate the occurrence of IUGR. A cross talk between the pregnancy hormone progesterone and innate immune cell subsets such as dendritic cells (DCs) is vital to ensure adequate placentation and fetal growth. However, experimental strategies to pinpoint distinct immune cell subsets interacting with progesterone in vivo have long been limited. In the present study, we have overcome this limitation by generating a mouse line with a specific deletion of the progesterone receptor (PR) on CD11c⁺ DCs. We took advantage of the cre/loxP system and assessed reproductive outcome in Balb/c-mated C57Bl/6 PR^flox/floxCD11c^cre/wt females. Balb/c-mated C57Bl/6 PR^wt/wtCD11c^cre/wt females served as controls. In all dams, fetal growth and development, placental function and maternal immune and endocrine adaptation were evaluated at different gestational time points. We observed a significantly reduced fetal weight on gestational day 13.5 and 18.5 in PR^flox/floxCD11c^cre/wt females. While frequencies of uterine CD11c⁺ cells were similar in both groups, an increased frequency of co-stimulatory molecules was observed on DCs in PR^flox/floxCD11c^cre/wt mice, along with reduced frequencies of CD4⁺ FoxP3⁺ and CD8⁺ CD122⁺ regulatory T (Treg) cells. Placental histomorphology revealed a skew toward increased junctional zone at the expense of the labyrinth in implantations of PR^flox/floxCD11c^cre/wt females, accompanied by increased plasma progesterone concentrations. Our results support that DCs are highly responsive to progesterone, subsequently adapting to a tolerogenic phenotype. If such cross talk between progesterone and DCs is impaired, the generation of pregnancy-protective immune cells subsets such as CD4⁺ and CD8⁺ Treg cells is reduced, which is associated with poor placentation and IUGR in mice.