Cryptochrome 2 Suppresses Epithelial-Mesenchymal Transition by Promoting Trophoblastic Ferroptosis in Unexplained Recurrent Spontaneous Abortion

Unexplained recurrent spontaneous abortion (URSA) is a serious reproductive issue that affects women of childbearing age. Studies have shown a close association between disrupted circadian rhythm and impaired epithelial-mesenchymal transition (EMT) in trophoblasts during URSA, although the underlying mechanism is not known. The current study investigated the regulatory relationship between circadian rhythm gene cryptochrome 2 (CRY2) and ferroptosis on the migratory ability of trophoblast cells. Cell proliferation experiments, wound-healing assays, and expression of related markers were conducted to study EMT. Trophoblastic ferroptosis was confirmed by the expressions of malondialdehyde, glutathione, mitochondrial membrane potential, divalent iron ions, and related genes. The results showed significant increased expression of CRY2 and decreased expression of brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) in the URSA villous tissues, accompanied by iron-dependent oxidative changes and abnormal expression of ferroptosis-related proteins. CRY2 and BMAL1 were co-localized and functioned as a feedback loop, which regulated the dynamic changes of EMT-related markers in trophoblast cells. CRY2 promoted trophoblastic ferroptosis, whereas BMAL1 had the opposite effect. Particularly, the ferroptosis inhibitor (ferrostatin-1) effectively reversed the trophoblastic ferroptosis and EMT inhibition caused by CRY2 overexpression. Collectively, these results suggest that CRY2 regulates trophoblastic ferroptosis and hinders cellular EMT and migratory ability by suppressing BMAL1 expression.

Association between maternal and perinatal outcomes and histological changes in the placenta of patients with Covid-19: A cohort study

Although studies evaluated placental involvement in Covid-19 patients, few have assessed its association with clinical repercussions. The study aimed to determine the association between the clinical status and maternal and perinatal outcomes of patients with Covid-19 at delivery and changes in placental histology. It is so far the largest cohort evaluating placentas of patients infected by the SARS-CoV-2. A secondary analysis was conducted of a database from which a cohort of 226 patients, who tested real-time polymerase chain reaction-positive for Covid-19 at delivery and whose placentas were collected and submitted to pathology, was selected for inclusion. One or more types of histological changes were detected in 44.7% of the 226 placentas evaluated. The most common abnormalities were maternal vascular malperfusion (38%), evidence of inflammation/infection (9.3%), fetal vascular malperfusion (0.8%), fibrinoid changes and intervillous thrombi (0.4%). Oxygen use (P = .01) and need for admission to an intensive care unit (ICU) (P = .04) were less common in patients with placental findings, and hospital stay was shorter in these patients (P = .04). There were more fetal deaths among patients with evidence of inflammation/infection (P = .02). Fetal death, albeit uncommon, is associated with findings of inflammation/infection. Oxygen use and need for admission to an ICU were less common among patients with placental findings, probably due to the pregnancy being interrupted early. None of the other findings was associated with maternal clinical status or with adverse perinatal outcome.

Relationship between placental hemodynamics and placental histological analysis in third trimester

AIM

To investigate whether vascularization index (VI), flow index (FI), and vascularization flow index (VFI) correlate with the pathological structure of the placenta and whether there were any differences in VI, FI, VFI, and placental pathological structure between the normal and preeclampsia (PE) groups.

METHODS

Fifty-five pregnant women (normal group, n = 27; PE group, n = 28) underwent VI, FI, and VFI at four locations in the placenta during the second and third trimesters. Two hematoxylin and eosin (HE)-stained specimens of the postpartum placenta were prepared. We randomly selected two of these locations and used ImageJ, an open-source image package, to quantify intervillous blood vessels (IBV), intervillous spaces (IS), and intervillous blood vessels + intervillous spaces (IBV + IS) per unit placenta and analyzed their correlation with VI, FI, and VFI.

RESULTS

There was no positive correlation between VI, FI, VFI, IBV, IS, and IBV + IS. There were no significant differences in VI, FI, and VFI between the normal and PE groups; however, there were significant differences in IBV, IS, and IBV + IS in the PE group compared to those in the normal group.

CONCLUSIONS

Placental hemodynamics measured by VI, FI, and VFI were not positively correlated with placental morphology in the third trimester. There were no differences in the VI, FI, and VFI in the third trimester between the normal and PE groups, suggesting that these may reflect placental circulatory insufficiency.

Association of placental histology and neonatal hematologic outcomes

OBJECTIVE

The objective of the paper was to investigate how neonatal hematologic outcomes vary by major placental histopathology categories.

STUDY DESIGN

Placental pathology reports from 5263 subjects were coded into individual placental lesions. Infant hematologic data (complete blood count parameters (n = 1945), transfusions, and phototherapy) were compared by placental pathologic phenotype.

RESULTS

Red blood cell transfusions were more likely with maternal vascular malperfusion (MVM; OR 9.4 [2.2, 40.8]) and chronic inflammation (1.7 [1.04, 2.7]). White blood cells were decreased with MVM (10.6 10³/μL vs 16.4) and elevated with acute inflammation (AI; 18.6 vs 11.9). Thrombocytopenia was associated with MVM (OR 3.7 [2.2, 5.1]) and fetal vascular malperfusion (FVM; OR 2.6 [1.5, 4.6]). Platelet transfusions were more likely with MVM (OR 8.3 [4.6, 15.0]) and FVM (OR 2.9 [1.4, 6.1]). Phototherapy was associated with MVM (OR 3.3 [2.7, 4.0]) and AI (OR 0.8 [0.6, 0.9]).

CONCLUSIONS

Neonatal hematologic outcomes are associated with the in utero environment described by placental pathology.

Effects of Gestational Intermittent Hypoxia on Placental Morphology and Fetal Development in a Murine Model of Sleep Apnea

Obstructive sleep apnea (OSA) during pregnancy is characterized by episodes of intermittent hypoxia (IH) during sleep, resulting in adverse health outcomes for mother and offspring. Despite a prevalence of 8-20% in pregnant women, this disorder is often underdiagnosed.We have developed a murine model of gestational OSA to study IH effects on pregnant mothers, placentas, fetuses, and offspring. One group of pregnant rats was exposed to IH during the last 2 weeks of gestation (GIH). One day before the delivery date, a cesarean section was performed. Other group of pregnant rats was allowed to give birth at term to study offspring's evolution.Preliminary results showed no significant weight differences in mothers and fetuses. However, the weight of GIH male offspring was significantly lower than the controls at 14 days (p < 0.01). The morphological study of the placentas showed an increase in fetal capillary branching, expansion of maternal blood spaces, and number of cells of the external trophectoderm in the tissues from GIH-exposed mothers. Additionally, the placentas from the experimental males were enlarged (p < 0.05). Further studies are needed to follow the long-term evolution of these changes to relate the histological findings of the placentas with functional development of the offspring in adulthood.

Vascular Malperfusion – As a Morphological Pattern of Preeclampsia

Introduction. The system « mother-placenta-fetus » is in a complex functional balance, and dysfunction of any of the components can compromise others. The placenta plays an important role in the development of preeclampsia, since preeclampsia can occur in the absence of a fetus, but in the presence of a trophoblast. In this regard, the study of morphological placental patterns in preeclampsia can give an idea of preeclampsia as a pathology in general, as well as its relationship with hypoxic damage to the fetus. Aim.  Identification of morphological patterns of placental lesions associated with preeclampsia. Materials and methods. A retrospective morphological study of 355 placentas sent for histological examination in the period from 2015 to 2020 was carried out. During the analyzed period, 184 placentas from pregnancies with an established diagnosis of preeclampsia and 171 placentas from pregnancies with a physiological course were studied. Results. It has been established that preeclampsia is associated with a smaller mass, size and height of the placenta. As morphological patterns associated with preeclampsia, such histological signs of maternal vascular malperfusion, such as infarcts, arterial atherosclerosis, etc., were identified. Conclusions. The heterogeneity of clinical and histological signs associated with both the physiological and pathological course of pregnancy reflects the different gestational age of the onset of the disease and the stage of development of the adaptive capabilities of the placenta. Identification of morphological patterns associated with hypoxic damage to the fetus allows us to identify a group of newborns with a high risk of chronic hypoxic damage in the perinatal period and to stratify the risk group in the postnatal period in order to reduce infant morbidity and mortality.

DJ-1 upregulates the Nrf2/GPX4 signal pathway to inhibit trophoblast ferroptosis in the pathogenesis of preeclampsia

Ferroptosis is a newly discovered mode of cell death that involves disorders in iron metabolism and the accumulation of reactive oxygen species (ROS) in the plasma membrane. Preeclampsia (PE) is a gestational idiopathic disease that is characterized by hypertension and albuminuria, begins after 20 weeks of pregnancy. DJ-1 is a prerequisite for activating and stabilizing Nrf2 to allow translocation to the nucleus to carry out further functions. Detecting the expression levels of DJ-1, the Nrf2/GPX4 signaling pathway and ferroptosis markers in placental tissues of pregnant women with and without PE. Analyzing the effects of the ferroptosis inducer (RSL3) and the inhibitor (Fer-1) on the mortality rate of BeWo cells and DJ-1+/+, DJ-1-/- BeWo cells. Ferroptosis markers (MDA concentration and morphology of trophoblast cells) and DJ-1 and its downstream the Nrf2/GPX4 signaling pathway increased significantly in PE pathological state. The expression levels of DJ-1 protein in the control group and the PE group were positively correlated with the expression levels of Nrf2/GPX4 signaling pathway protein, and negatively correlated with the MDA concentration. BeWo cells were sensitive to the ferroptosis inducer (RSL3) and the inhibitor (Fer-1). The high expression levels of DJ-1 in BeWo cells can resist ferroptosis by regulating the Nrf2/GPX4 signaling pathway. Ferroptosis is involved in the pathogenesis of PE. DJ-1 can mediate the trophoblast cells ferroptosis and play a protective role in the pathogenesis of preeclampsia by regulating the Nrf2/GPX4 signaling pathway.

Maternal and fetal vascular lesions of malperfusion in the placentas associated with fetal and neonatal death: results of a prospective observational study

BACKGROUND

Fetal death is one of the major adverse pregnancy outcomes and is common in low- and middle-income countries. Placental lesions may play an important role in the etiology of fetal and neonatal deaths. Previous research relating placental lesions to fetal death causation was hindered by a lack of agreement on a placental classification scheme. The Amsterdam consensus statement that was published in 2016 focused its attention on malperfusions in the maternal and fetal placental circulations.

OBJECTIVE

This study aimed to investigate the relationships of placental maternal and fetal vascular malperfusions in fetal and neonatal deaths, focusing on the most important maternal clinical conditions in the pathway to fetal and neonatal deaths, such as maternal hypertension, antepartum hemorrhage, and decreased fetal growth.

STUDY DESIGN

This was a prospective, observational cohort study conducted at 2 Asian sites. The data collected included clinical history, gross and histologic evaluations of the placenta, and several other investigations and were used to determine the cause of death. The placenta was evaluated at both sites using the Amsterdam consensus framework. We estimated the risk of placental maternal and fetal vascular malperfusions in fetal and neonatal deaths.

RESULTS

Between July 2018 and January 2020 in India and Pakistan, 1633 women with placentas available for the study provided consent. Of these women, 814 had fetal deaths, 618 had preterm live births and subsequent neonatal deaths, and 201 had term live births. The prevalence of maternal vascular malperfusion was higher in the placentas associated with fetal deaths (58.4%) and preterm neonatal deaths (31.1%) than in the placentas associated with term live births (15.4%). Adjusting for site, maternal vascular malperfusion had a relative risk of 3.88 (95% confidence interval, 2.70-5.59) in fetal deaths vs term live births and a relative risk of 2.07 (95% confidence interval, 1.41-3.02) in preterm neonatal deaths vs term live births. Infarcts and distal villous hypoplasia were the most common histologic components of maternal vascular malperfusion. Compared with maternal vascular malperfusion (58.4%), fetal vascular malperfusion was less common in the placentas associated with fetal deaths (19.0%). However, there were higher frequencies of fetal vascular malperfusion in the placentas associated with fetal deaths (19.0%) than in placentas associated with neonatal deaths (8.3%) or term live birth (5.0%). Adjusting for site, fetal vascular malperfusion had a relative risk of 4.09 (95% confidence interval, 2.15-7.75) in fetal deaths vs term live births and a relative risk of 1.77 (95% confidence interval, 0.90-3.49) in preterm neonatal deaths vs term live births. Furthermore, there was a higher incidence of maternal vascular malperfusion in cases of maternal hypertension (71.4%), small for gestational age (69.9%), and antepartum hemorrhage (59.1%) than in cases of fetal deaths with none of these conditions (43.3%). There was no significant difference in the occurrence of fetal vascular malperfusion in the 4 clinical categories.

CONCLUSION

Histologic examination of the placenta, especially for malperfusion disorders, is crucial in elucidating pathways to fetal and neonatal deaths in preterm infants. In particular, focusing on placental maternal and fetal vascular malperfusions during pregnancy is a means to identify fetuses at risk of fetal death and is an important strategy to reduce the risk of fetal death early delivery. We hope that the increased risk of fetal and neonatal deaths in these pregnancies can be reduced by the development of an intervention that reduces the likelihood of developing maternal and fetal vascular malperfusion.

Is obesity in pregnancy associated with signs of chronic fetal hypoxia?

INTRODUCTION

The prevalence of obesity in pregnancy is increasing worldwide. Maternal obesity increases risks of severe fetal and neonatal complications. The underlying pathophysiological mechanisms are unclear. One possible contributing factor could be chronic fetal hypoxia. The aim of this study was to compare placentas from women with and without obesity with respect to placental lesions, which could reflect compensatory mechanisms in response to chronic fetal hypoxia as well as lesions possibly leading to chronic fetal hypoxia. In addition, levels of erythropoietin in cord blood were compared between offspring of lean and obese women.

MATERIAL AND METHODS

This cohort study included 180 women with uneventful, full-term, singleton pregnancies, out of which 91 lean women had a body mass index (BMI) of 18.5-24.9 kg/m² and 89 women had obesity (BMI ≥30 kg/m² ). Women were recruited at Södersjukhuset between 16 October 2018 and 2 December 2019. Placentas were investigated by two senior perinatal pathologists, who were blinded for maternal BMI. Cord blood was analyzed for levels of erythropoietin.

RESULTS

Levels of erythropoietin in cord blood increased with maternal BMI (P = .01, β = 0.97, 95% CI 0.27-1.68). There was no difference between placentas of obese and lean women in number of placental lesions reflecting chronic fetal hypoxia or in lesions that could possibly lead to chronic fetal hypoxia.

CONCLUSIONS

This study of term and uneventful pregnancies demonstrated a positive association between maternal obesity and concentrations of erythropoietin in cord blood at birth. This finding supports the hypothesis of chronic fetal hypoxia as a risk factor for complications in the pregnancies of obese women. There were no differences in lesions associated with hypoxia between placentas of obese and lean women.

Disorders of placental villous maturation in fetal death

Objective The aims of this study were to ascertain the frequency of disorders of villous maturation in fetal death and to also delineate other placental histopathologic lesions in fetal death. Methods This was a retrospective observational cohort study of fetal deaths occurring among women between January 2004 and January 2016 at Hutzel Women's Hospital, Detroit, MI, USA. Cases comprised fetuses with death beyond 20 weeks' gestation. Fetal deaths with congenital anomalies and multiple gestations were excluded. Controls included pregnant women without medical/obstetrical complications and delivered singleton, term (37-42 weeks) neonate with 5-min Apgar score ≥7 and birthweight between the 10th and 90th percentiles. Results Ninety-two percent (132/143) of placentas with fetal death showed placental histologic lesions. Fetal deaths were associated with (1) higher frequency of disorders of villous maturation [44.0% (64/143) vs. 1.0% (4/405), P < 0.0001, prevalence ratio, 44.6; delayed villous maturation, 22% (31/143); accelerated villous maturation, 20% (28/143); and maturation arrest, 4% (5/143)]; (2) higher frequency of maternal vascular malperfusion lesions [75.5% (108/143) vs. 35.7% (337/944), P < 0.0001, prevalence ratio, 2.1] and fetal vascular malperfusion lesions [88.1% (126/143) vs. 19.7% (186/944), P < 0.0001, prevalence ratio, 4.5]; (3) higher frequency of placental histologic patterns suggestive of hypoxia [59.0% (85/143) vs. 9.3% (82/942), P < 0.0001, prevalence ratio, 6.8]; and (4) higher frequency of chronic inflammatory lesions [53.1% (76/143) vs. 29.9% (282/944), P < 0.001, prevalence ratio 1.8]. Conclusion This study demonstrates that placentas of women with fetal death were 44 times more likely to present disorders of villous maturation compared to placentas of those with normal pregnancy. This suggests that the burden of placental disorders of villous maturation lesions is substantial.

Irisin induces trophoblast differentiation via AMPK activation in the human placenta

Irisin, an adipokine, regulates differentiation and phenotype in various cell types including myocytes, adipocytes, and osteoblasts. Circulating irisin concentration increases throughout human pregnancy. In pregnancy disorders such as preeclampsia and gestational diabetes mellitus, circulating irisin levels are reduced compared to healthy controls. To date, there are no data on the role and molecular function of irisin in the human placenta or its contribution to pathophysiology. Aberrant trophoblast differentiation is involved in the pathophysiology of preeclampsia. The current study aimed to assess the molecular effects of irisin on trophoblast differentiation and function. First-trimester placental explants were cultured and treated with low (10 nM) and high (50 nM) physiological doses of irisin. Treatment with irisin dose-dependently increased both in vitro placental outgrowth (on Matrigel™) and trophoblast cell-cell fusion. Adenosine monophosphate-activated protein kinase (AMPK) signaling, an important regulator of cellular energy homeostasis that is involved in trophoblast differentiation and pathology, was subsequently investigated. Here, irisin exposure induced placental AMPK activation. To determine the effects of irisin on trophoblast differentiation, two trophoblast-like cell lines, HTR-8/SVneo and BeWo, were treated with irisin and/or a specific AMPK inhibitor (Compound C). Irisin-induced AMPK phosphorylation in HTR-8/SVneo cells. Additionally, as part of the differentiation process, integrin switching from α6 to α1 occurred as well as increased invasiveness. Overall, irisin promoted differentiation in villous and extravillous cell-based models via AMPK pathway activation. These findings provide evidence that exposure to irisin promotes differentiation and improves trophoblast functions in the human placenta that are affected in abnormal placentation.

Perinatal Micro-Bleeds and Neuroinflammation in E19 Rat Fetuses Exposed to Utero-Placental Ischemia

Offspring of preeclampsia patients have an increased risk of developing neurological deficits and cognitive impairment. While low placental perfusion, common in preeclampsia and growth restriction, has been linked to neurological deficits, a causative link is not fully established. The goal of this study was to test the hypothesis that placental ischemia induces neuroinflammation and micro-hemorrhages in utero. Timed-pregnant Sprague Dawley rats were weight-matched for sham surgery (abdominal incision only) or induced placental ischemia (surgical reduction of utero-placental perfusion (RUPP)); n = 5/group on gestational day 14. Fetal brains (n = 1–2/dam/endpoint) were collected at embryonic day (E19). Placental ischemia resulted in fewer live fetuses, increased fetal demise, increased hematocrit, and no difference in brain water content in exposed fetuses. Additionally, increased cerebral micro-bleeds (identified with H&E staining), pro-inflammatory cytokines: IL-1β, IL-6, and IL-18, eotaxin (CCL11), LIX (CXCL5), and MIP-2 (CXCL2) were observed in RUPP-exposed fetuses. Microglial density in the sub-ventricular zone decreased in RUPP-exposed fetuses, with no change in cortical thickness. Our findings support the hypothesis that exposure to placental ischemia contributes to microvascular dysfunction (increased micro-bleeds), fetal brain inflammation, and reduced microglial density in proliferative brain areas. Future studies will determine whether in utero abnormalities contribute to long-term behavioral deficits in preeclampsia offspring through impaired neurogenesis regulation.

[Angiogenesis-related factors in the placenta of pregnant women with congenital heart diseases]

OBJECTIVE

To study the features of angiogenesis of the placental villous chorion in women whose gestation took place in congenital heart disease (CHD).

MATERIAL AND METHODS

Thirty-five placentas obtained from women with full-term pregnancy, including 20 cases of non-operated CHD and 15 as a result of physiological pregnancy and childbirth (a control group), were studied. A placental morphological examination was made according to the standard scheme using routine stains and immunohistochemical techniques involving reactions with mouse monoclonal antibodies against VEGF, CD34, and SMA.

RESULTS

The placentas of women with CHD showed a set of pathological changes, including impaired chorionic villous maturation and marked dystrophic and necrobiotic changes, the latter being more common in the placental marginal zones. Placental VEGF expression in women with CHD was significantly higher than that in the controls, especially at the edge of the placental disc. On the contrary, CD34 expression in all placental sections was lower in CHD. The distribution of SMA in the myofibroblasts of chorionic villous vessels in CHD was characterized by diffuse growth of actin expression. The specific volume of the cell surface with a positive reaction to actin significantly increased in the center, especially in the peripheral zone.

CONCLUSION

Thus, the analysis of the studies could establish that hemodynamic disturbance during gestation complicated by CHD was accompanied by remodeling of the villous chorion. Pathological changes in the placental barrier complicate metabolism and gas exchange in the fetoplacental complex. Microvascular remodeling is an important mechanism of placental adaptation to circulatory hypoxic conditions in the presence of CHD and a prerequisite for successful pregnancy termination and childbirth in disease.

Preeclampsia: The Relationship between Uterine Artery Blood Flow and Trophoblast Function

Maternal uterine artery blood flow is critical to maintaining the intrauterine environment, permitting normal placental function, and supporting fetal growth. It has long been believed that inadequate transformation of the maternal uterine vasculature is a consequence of primary defective trophoblast invasion and leads to the development of preeclampsia. That early pregnancy maternal uterine artery perfusion is strongly associated with placental cellular function and behaviour has always been interpreted in this context. Consistently observed changes in pre-conceptual maternal and uterine artery blood flow, abdominal pregnancy implantation, and late pregnancy have been challenging this concept, and suggest that abnormal placental perfusion may result in trophoblast impairment, rather than the other way round. This review focuses on evidence that maternal cardiovascular function plays a significant role in the pathophysiology of preeclampsia.

Chronic gestational hypoxia accelerates ovarian aging and lowers ovarian reserve in next-generation adult rats

Chronic fetal hypoxia is a common complication observed in human pregnancy, impacting pregnancies across global contexts. Exposure to chronic intrauterine hypoxia has major short- and long-term consequences for offspring health. However, the impact of chronic gestational hypoxia on female reproductive system development is unknown. We aimed to understand the impact of exposure to chronic fetal hypoxia on the developing female reproductive system. Wistar rat dams underwent normoxia (21%) or hypoxia (13%) during pregnancy. Postnatally, all female offspring were maintained in normoxic conditions into early adulthood. Female rats exposed to chronic gestational hypoxia (13%) during their intrauterine development had decreased ovarian primordial follicular reserve compared to controls (P < 0.05). Adult females who had been exposed to chronic fetal hypoxia had significantly reduced somatic ovarian telomere length (P < 0.05) and reduced ovarian protein expression of KU70, a critical component of the DNA-activated protein kinase repair complex (P < 0.01). Gene expression of NADPH oxidase 2-mediated oxidative stress markers was increased (P < 0.05). Exposure to chronic hypoxia during fetal development leads to accelerated aging of the somatic ovary and decreased ovarian reserve in adulthood. Ovarian aging is highly sensitive to gestational hypoxia, with implications for future fertility in next-generation offspring of high-risk pregnancies.-Aiken, C. E., Tarry-Adkins, J. L., Spiroski, A.-M., Nuzzo, A. M., Ashmore, T. J., Rolfo, A., Sutherland, M. J., Camm, E. J., Giussani, D. A., Ozanne, S. E. Chronic gestational hypoxia accelerates ovarian aging and lowers ovarian reserve in next-generation adult rats.