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.

Special Issue "Physiology and Pathophysiology of Placenta 2.0".

We are pleased to present this Special Issue of the International Journal of Molecular Sciences, entitled "Physiology and Pathophysiology of Placenta 2 [...].

Placental mesenchymal disease masquerading as molar pregnancy with a favourable maternal and fetal outcome.

Placental mesenchymal dysplasia (PMD) is an exceptionally rare placental anomaly characterised by placentomegaly and grape-like vesicles resembling partial mole on ultrasonography, yet it can coexist with a viable fetus. We present the case of a primigravida who presented at 22 weeks gestation with a suspected partial mole but with a normally growing fetus. The differential diagnoses considered included placental mesenchymal disease, partial mole and twin pregnancy with molar pregnancy. With normal beta HCG levels and prenatal invasive testing reports, a probable diagnosis of PMD was made, and after thorough counselling, the decision was made to continue the pregnancy. The pregnancy progressed until 37 weeks, culminating in the uneventful delivery of a 2.4 kg healthy male infant. Histopathology confirmed PMD. Early recognition and management of PMD pose significant challenges, given its rarity. Prenatal identification of PMD during both early and late gestation could avert unnecessary termination of pregnancy.

Association of placental histopathological findings with COVID-19 and its predictive factors.

Objective: The aims of the study are to describe the association of coronavirus disease (COVID-19) with the abnormal histopathological findings in human placenta and to highlight the potential predictors of these histopathological findings. Methods: A retrospective cohort study, held in two obstetric units from January 2021- 2022, 34 patients who were confirmed cases of COVID- 19 were followed up till the time of delivery as their placenta were sent for histopathology. Patients diagnosed with other viral infections, chorioamnionitis, or were known case of as pre-term or term pre labour rupture of membrans (PROM) were excluded as well as pre exisiting diabetes mellitus or pre-eclampsia. Data analysis were performed using STATA software version 16. Result: Specific histopatological findings (fetal vascular malperfusion, maternal vascular malperfusion, inflammatory pathology and thrombotic finding) were significantly high among 13 (38.2%) of the study group who got infected earlier in pregnancy (P<0.001). The period between the diagnosis of COVID-19 and the delivery significantly increases the odds of the presence of pathological findings by 2.75 times for each week the patients getting infected earlier. Conclusion: Association of abnormal placental histopathological findings with COVID-19 infection in pregnancy and the potential predictor for the occurrence of placental findings is the longer duration between the diagnosis of the infection and the delivery.

Apoptotic and non-apoptotic roles of caspases in placenta physiology and pathology.

Caspases, a family of cysteine proteases, are pivotal regulators of apoptosis, the tightly controlled cell death process crucial for eliminating excessive or unnecessary cells during development, including placental development. Collecting research has unveiled the multifaceted roles of caspases in the placenta, extending beyond apoptosis. Apart from their involvement in placental tissue remodeling via apoptosis, caspases actively participate in essential regulatory processes, such as trophoblast fusion and differentiation, significantly influencing placental growth and functionality. In addition, growing evidence indicates an elevation in caspase activity under pathological conditions like pre-eclampsia (PE) and intrauterine growth restriction (IUGR), leading to excessive cell death as well as inflammation. Drawing from advancements in caspase research and placental development under both normal and abnormal conditions, we examine the significance of caspases in both cell death (apoptosis) and non-cell death-related processes within the placenta. We also discuss potential therapeutics targeting caspase-related pathways for placenta disorders.

Identification of hub genes in placental dysfunction and recurrent pregnancy loss through transcriptome data mining: A meta-analysis.

Recurrent pregnancy loss (RPL) is a condition characterized by the loss of two or more pregnancies before 20 weeks of gestation. The causes of RPL are complex and can be due to a variety of factors, including genetic, immunological, hormonal, and environmental factors. This transcriptome data mining study was done to explore the differentially expressed genes (DEGs) and related pathways responsible for pathogenesis of RPL using an Insilco approach. RNAseq datasets from the Gene Expression Omnibus (GEO) database was used to extract RNAseq datasets of RPL. Meta-analysis was done by ExpressAnalyst. The functional and pathway enrichment analysis of DEGs were performed using KEGG and BINGO plugin of Cytoscape software. Protein-protein interaction was done using STRING and hub genes were identified. A total of 91 DEGs were identified, out of which 10 were downregulated and 81 were upregulated. Pathway analysis indicated that majority of DEGs were enriched in immunological pathways (IL-17 signalling pathway, TLR-signalling pathway, autoimmune thyroid disease), angiogenic VEGF-signalling pathway and cell-cycle signalling pathways. Of these, 10 hub genes with high connectivity were selected (CXCL8, CCND1, FOS, PTGS2, CTLA4, THBS1, MMP2, KDR, and CD80). Most of these genes are involved in maintenance of immune response at maternal-fetal interface. Further, in functional enrichment analyses revealed the highest node size in regulation of biological processes followed by cellular processes, their regulation and regulation of multicellular organismal process. This in-silico transcriptomics meta-analysis findings could potentially contribute in identifying novel biomarkers and therapeutic targets for RPL, which could lead to the development of new diagnostic and therapeutic strategies for this condition.

Prospective study of malaria in pregnancy, placental and congenital malaria in Northwest Colombia.

BACKGROUND: Pregnancy Associated Malaria (PAM) include malaria in pregnancy (MiP), placental malaria (PM), and congenital malaria (CM). The evidence available in Colombia on PAM focuses on one of the presentations (MiP, PM or CM), and no study longitudinally analyses the infection from the pregnant woman, passing through the placenta, until culminating in the newborn. This study determined the frequency of MiP, PM, and CM caused by Plasmodium vivax, Plasmodium falciparum, or mixed infections, according to Thick Blood Smear (TBS) and quantitative Polymerase Chain Reaction (qPCR). Identifying associated factors of PAM and clinical-epidemiological outcomes in northwestern Colombia. METHODS: Prospective study of 431 pregnant women, their placenta, and newborns registered in the data bank of the research Group "Salud y Comunidad César Uribe Piedrahíta" which collected information between 2014 and 2020 in endemic municipalities of the departments of Córdoba and Antioquia. The frequency of infection was determined with 95% confidence intervals. Comparisons were made with the Chi-square test, Student t-test, prevalence ratios, and control for confounding variables by log-binomial regression. RESULTS: The frequency of MiP was 22.3% (4.6% using TBS), PM 24.8% (1.4% using TBS), and CM 11.8% (0% using TBS). Using TBS predominated P. vivax. Using qPCR the proportions of P. vivax and P. falciparum were similar for MiP and PM, but P. falciparum predominated in CM. The frequency was higher in nulliparous, and women with previous malaria. The main clinical effects of PAM were anaemia, low birth weight, and abnormal APGAR score. CONCLUSIONS: The magnitude of infections was not detected with TBS because most cases were submicroscopic (TBS-negative, qPCR-positive). This confirmed the importance of improving the molecular detection of cases. PAM continue being underestimated in the country due to that in Colombia the control programme is based on TBS, despite its outcomes on maternal, and congenital health.

d-galactose causes embryonic development arrest and placental development disorders in mice by increasing ROS and inhibiting SIRT1/FOXO3a axis.

INTRODUCTION: Does an elevation in d-Galactose (D-Gal) levels within the body contribute to abnormal embryonic development and placental dysfunction during pregnancy? METHODS: Mouse embryos were cultivated to the blastocyst stage under varying concentrations of D-Gal. The blastocyst formation rate was measured, and the levels of reactive oxygen species (ROS), sirtuin 1 (SIRT1), and forkhead box O3a (FOXO3a) in blastocysts were assessed. Mice were intraperitoneally injected with either saline or D-Gal with or without SRT1720. On the 14th day of pregnancy, the fetal absorption rate and placental weight were recorded. Placental levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were determined. The expression of senescence-related factors, such as senescence-associated ß-galactosidase (SA-ß-gal) in the placenta was examined, and the expression of placental SIRT1, FOXO3a and p21 was evaluated by immunohistochemistry and Western blotting. RESULTS: D-Gal adversely affects early embryonic development in vitro, resulting in a decreased blastocyst formation rate. Furthermore, D-Gal downregulates SIRT1 and FOXO3a while increasing ROS levels in blastocysts. Concurrently, D-Gal induces placental dysfunction, characterized by an elevated fetal absorption rate, reduced placental weight, diminished SOD activity, and increased MDA content. The senescence-related factor SA-ß-gal was detected in the placenta, along with altered expression of placental SIRT1, FOXO3a, and p21. The SIRT1 agonist SRT1720 mitigated this damage by increasing SIRT1 and FOXO3a expression. DISCUSSION: The inhibition of early embryonic development and placental dysfunction induced by D-Gal may be attributed to the dysregulation of SIRT1. Activating SIRT1 emerges as a potentially effective strategy for alleviating the adverse effects of D-Gal exposure.

Whole exome sequencing of placental chorangioma.

INTRODUCTION: Placental chorangioma is a benign non-trophoblastic vascular proliferation of the placental chorion favored to represent hamartoma-like or hyperplastic capillary lesions. As the exact pathophysiology has not been established, we investigated the molecular characteristics of placental chorangiomas using exploratory whole exome sequencing. METHODS: Three cases were retrospectively selected and whole exome sequencing was performed on macrodissected lesions. DNA extraction, DNA quantification, library preparation and sequencing were performed with IDT xGen™ Exome Hybridization Panel v2 for library capture. Sequencing data was analyzed with an in-house bioinformatics pipeline for single-nucleotide variants and insertions/deletions. RESULTS: All neonates were delivered at term and had birth weights ranging from 11th-35th percentile for gestational age. All mothers presented with hypertensive disorder during pregnancy. Chorangiomas ranged from 0.7 cm to 5.1 cm and were well-circumscribed near the fetal surface. Case 1 showed a background of chorangiosis and acute subchorionitis, while case 2 had foci of chronic lymphocytic villitis. Whole exome sequencing did not reveal any significant pathologic variants. DISCUSSIONS: The absence of molecular alteration in placental chorangioma is likely indicative of the reactive/non-neoplastic nature of this lesion. The presence of compromised blood flow in the form of hypertensive disorders in our cases may be one of its underlying pathophysiologic mechanisms.

Maternal obesity and placental function: impaired maternal-fetal axis.

The prevalence of maternal obesity rapidly increases, which represents a major public health concern worldwide. Maternal obesity is characteristic by metabolic dysfunction and chronic inflammation. It is associated with health problems in both mother and offspring. Increasing evidence indicates that the placenta is an axis connecting maternal obesity with poor outcomes in the offspring. In this brief review, we have summarized the current data regarding deregulated placental function in maternal obesity. The data show that maternal obesity induces numerous placental defects, including lipid and glucose metabolism, stress response, inflammation, immune regulation and epigenetics. These placental defects affect each other and result in a stressful intrauterine environment, which transduces and mediates the adverse effects of maternal obesity to the fetus. Further investigations are required to explore the exact molecular alterations in the placenta in maternal obesity, which may pave the way to develop specific interventions for preventing epigenetic and metabolic programming in the fetus.

Images in abnormal placenta: a rare case of "blood bag" formation in placenta membranacea.

Placenta membranacea is an uncommon placental anomaly. Here, we present the case of a 30-year-old primiparous woman admitted for thickened placenta and reduced amniotic fluid. A follow-up ultrasound, performed after 48 h, revealed that the placental parenchyma was thin and not adequately visualized, enclosing a substantial volume of flowing blood (150 mm), with an amniotic fluid index of 18 mm. An emergency cesarean section was promptly performed. Following fetal delivery, a substantial accumulation of dark red blood within the fetal membranes created a "blood bag", estimated at approximately 3000 ml. This observation aligned with the ultrasound findings, and both placental morphology and pathological results substantiated the diagnosis of placenta membranacea.

An Update on COVID-19-Associated Placental Pathologies.

COVID-19 pregnancies are associated with increased rates of premature delivery and stillbirths. It is still a matter of debate whether there is a COVID-19-associated pattern of placenta pathology. We updated our previously published results on a systematic literature review and meta-analysis of COVID-19 pregnancies. In total, 38 reports on 3677 placentas were evaluated regarding histopathological changes. Maternal vascular malperfusion (32%), fetal vascular malperfusion (19%), acute and chronic inflammation (20% and 22%) were frequent pathologies. In non-COVID-19 pregnancies, placentas show similar histologic patterns and mainly similar frequencies of manifestation. It has to be taken into account that there might be an observation bias, because some findings are diagnosed as a "pathology" that might have been classified as minor or unspecific findings in non-COVID-19 placentas. COVID-19 placentitis occurs in 1-2% of cases at the most. In conclusion, this updated meta-analysis indicates that COVID-19 infection during pregnancy does not result in an increased rate of a specific placenta pathology and COVID-19 placentitis is rare.

Placenta accreta spectrum disorder at single-cell resolution: a loss of boundary limits in the decidua and endothelium.

BACKGROUND: Placenta accreta spectrum disorders are associated with severe maternal morbidity and mortality. Placenta accreta spectrum disorders involve excessive adherence of the placenta preventing separation at birth. Traditionally, this condition has been attributed to excessive trophoblast invasion; however, an alternative view is a fundamental defect in decidual biology. OBJECTIVE: This study aimed to gain insights into the understanding of placenta accreta spectrum disorder by using single-cell and spatially resolved transcriptomics to characterize cellular heterogeneity at the maternal-fetal interface in placenta accreta spectrum disorders. STUDY DESIGN: To assess cellular heterogeneity and the function of cell types, single-cell RNA sequencing and spatially resolved transcriptomics were used. A total of 12 placentas were included, 6 placentas with placenta accreta spectrum disorder and 6 controls. For each placenta with placenta accreta spectrum disorder, multiple biopsies were taken at the following sites: placenta accreta spectrum adherent and nonadherent sites in the same placenta. Of note, 2 platforms were used to generate libraries: the 10× Chromium and NanoString GeoMX Digital Spatial Profiler for single-cell and spatially resolved transcriptomes, respectively. Differential gene expression analysis was performed using a suite of bioinformatic tools (Seurat and GeoMxTools R packages). Correction for multiple testing was performed using Clipper. In situ hybridization was performed with RNAscope, and immunohistochemistry was used to assess protein expression. RESULTS: In creating a placenta accreta cell atlas, there were dramatic difference in the transcriptional profile by site of biopsy between placenta accreta spectrum and controls. Most of the differences were noted at the site of adherence; however, differences existed within the placenta between the adherent and nonadherent site of the same placenta in placenta accreta. Among all cell types, the endothelial-stromal populations exhibited the greatest difference in gene expression, driven by changes in collagen genes, namely collagen type III alpha 1 chain (COL3A1), growth factors, epidermal growth factor-like protein 6 (EGFL6), and hepatocyte growth factor (HGF), and angiogenesis-related genes, namely delta-like noncanonical Notch ligand 1 (DLK1) and platelet endothelial cell adhesion molecule-1 (PECAM1). Intraplacental tropism (adherent versus non-adherent sites in the same placenta) was driven by differences in endothelial-stromal cells with notable differences in bone morphogenic protein 5 (BMP5) and osteopontin (SPP1) in the adherent vs nonadherent site of placenta accreta spectrum. CONCLUSION: Placenta accreta spectrum disorders were characterized at single-cell resolution to gain insight into the pathophysiology of the disease. An atlas of the placenta at single cell resolution in accreta allows for understanding in the biology of the intimate maternal and fetal interaction. The contributions of stromal and endothelial cells were demonstrated through alterations in the extracellular matrix, growth factors, and angiogenesis. Transcriptional and protein changes in the stroma of placenta accreta spectrum shift the etiologic explanation away from "invasive trophoblast" to "loss of boundary limits" in the decidua. Gene targets identified in this study may be used to refine diagnostic assays in early pregnancy, track disease progression over time, and inform therapeutic discoveries.

Stillbirth and the placenta.

Stillbirth affects a large proportion of pregnancies world-wide annually and continues to be a major public health concern. Several causes of stillbirth have been identified and include obstetrical complications, placental abnormalities, fetal malformations, infections, and medical complications in pregnancy. Placental abnormalities such as placental abruption, chorioangioma, vasa previa, and umbilical cord abnormalities have been identified as causes of death for a significant proportion of stillbirths. In the absence of placental abnormalities, the gross and histologic changes in the placenta in stillbirth are found when secondary to other etiologies. Here we describe both gross and histologic changes of the placenta that are associated with stillbirth.

Directed Differentiation of Human Pluripotent Stem Cells to Cytotrophoblast and Syncytiotrophoblast.

Human pluripotent stem cells (hPSCs) form an ideal system to study the formation of placental cells, from an undifferentiated human embryonic stem cell state. The conventional human in vitro model systems to study the human placenta cannot be employed for understanding placental dysfunctions or the development of specialized placental cell types. Hence, human PSCs make an ideal model system to study human placental development and disorders. Here, we describe an efficient and validated protocol to reproducibly study the formation of human cytotrophoblasts (CTBs) and syncytiotrophoblast (STBs) from undifferentiated hPSCs. CTBs are the trophoblast stem cells that can differentiate into specialized placental cell types such as STBs. The multinucleated STB plays vital role in the exchange of nutrients and gases across the placenta and secretes several hormones during pregnancy, such as human chorionic gonadotropin ß (hCGß). Here we describe two methods of seeding the hPSCs: chemical (clumps method) and enzymatic methods (single cells) to differentiate them to CTB and STB, activating BMP (B) signaling and inhibiting ACTIVIN/NODAL and FGF signaling pathways (2i), thus naming our protocol as "B2i" (Sudheer et al., Stem Cells Dev 21:2987-3000, 2012). This protocol forms the perfect model system for understanding in vitro placentation, modeling diseases arising from abnormal placentation that cause complications such as miscarriage, preeclampsia or intrauterine growth restriction (IUGR), and drug discovery for placental disorders.

Development and validation of MRI-based scoring models for predicting placental invasiveness in high-risk women for placenta accreta spectrum.

OBJECTIVES: To develop and validate MRI-based scoring models for predicting placenta accreta spectrum (PAS) invasiveness. MATERIALS AND METHODS: This retrospective study comprised a derivation cohort and a validation cohort. The derivation cohort came from a systematic review of published studies evaluating the diagnostic performance of MRI signs for PAS and/or placenta percreta in high-risk women. The significant signs were identified and used to develop prediction models for PAS and placenta percreta. Between 2016 and 2021, consecutive high-risk pregnant women for PAS who underwent placental MRI constituted the validation cohort. Two radiologists independently evaluated the MRI signs. The reference standard was intraoperative and pathologic findings. The predictive ability of MRI-based models was evaluated using the area under the curve (AUC). RESULTS: The derivation cohort included 26 studies involving 2568 women and the validation cohort consisted of 294 women with PAS diagnosed in 258 women (88%). Quantitative meta-analysis revealed that T2-dark bands, placental/uterine bulge, loss of T2 hypointense interface, bladder wall interruption, placental heterogeneity, and abnormal intraplacental vascularity were associated with both PAS and placenta percreta, and myometrial thinning and focal exophytic mass were exclusively associated with PAS. The PAS model was validated with an AUC of 0.90 (95% CI: 0.86, 0.93) for predicting PAS and 0.85 (95% CI: 0.79, 0.90) for adverse peripartum outcome; the placenta percreta model showed an AUC of 0.92 (95% CI: 0.86, 0.98) for predicting placenta percreta. CONCLUSION: MRI-based scoring models established based on quantitative meta-analysis can accurately predict PAS, placenta percreta, and adverse peripartum outcome. CLINICAL RELEVANCE STATEMENT: These proposed MRI-based scoring models could help accurately predict PAS invasiveness and provide evidence-based risk stratification in the management of high-risk pregnant women for PAS. KEY POINTS: • Accurately identifying placenta accreta spectrum (PAS) and assessing its invasiveness depending solely on individual MRI signs remained challenging. • MRI-based scoring models, established through quantitative meta-analysis of multiple MRI signs, offered the potential to predict PAS invasiveness in high-risk pregnant women. • These MRI-based models allowed for evidence-based risk stratification in the management of pregnancies suspected of having PAS.

Massive perivillous fibrin deposition: Diagnosis, obstetrical features, and treatment.

MPVFD (Massive perivillous fibrin deposition) is placental lesion characterized by extensive massive deposits of fibrin in the intervillous space, extending over at least 25 % of the placental volume. Currently, this pathology can only be detected through histopathological examination of the placenta after a pregnancy has ended. The underlying mechanisms are poorly studied, there is no biomarker available for the diagnosis of MPVFD and treatment protocols are experimental and still lacking. The objective of this study is to systematically review the literature on the associated clinicopathologic features, treatment, and prognosis of MPVFD. We ended up with 17 studies, of these 12 studies were considered relevant for this article and included in the final analysis. All studies reporting MPVFD are retrospective. MPVFD is associated with recurrent miscarriage, intra uterine fetal death (IUFD), intra uterine growth restriction (IUGR) and preterm delivery. The prevalence in pregnancies with a delivery after 22 weeks of gestation was at 1.1 % and even higher to 2.7 % in recurrent early miscarriages. The reported risk of fetal death in MPVFD ranges mainly from 15 to 80 %. Preterm delivery is spontaneous in 50 to 70 % of cases and induced by of a severe intrauterine growth restriction (IUGR) in 30 to 50 % of cases depending on the study. Its causes and treatment are still poorly understood, although several avenues have been explored. This review summarizes current understanding of the prevalence, diagnostic features, clinical consequences, immune pathology, and potential prophylaxis against recurrence in this chronic inflammatory placental syndrome.

A novel technique to estimate intravillous fetal vasculature on routine placenta histologic sections.

Placental histopathologic lesions are dichotomized into "present" or "absent" and have limited inter-rater reliability. Continuous metrics are needed to characterize placental health and function. Tissue sections (N = 64) of human placenta were stained with CD34 antibody and hematoxylin. Proportion of the villous space occupied by fetal vascular endothelium (%FVE; pixels positive for CD34/total pixels) was evaluated for effect sizes associated with pregnancy outcomes, smoking status, and subtypes of lesions (n = 30). Time to fixation>60 min significantly increased the quantification. Large effect sizes were found between %FVE and both preterm birth and intrauterine growth restriction. These results demonstrate proof-of-concept for this vascular estimation.