Placental Cultures Research Articles

Adverse obstetric outcomes in cases of meconium-stained amniotic fluid complicated with intrapartum fever.

Meconium-stained amniotic fluid (MSAF) often signifies colonization of the amniotic sac by microorganisms. This study investigated additional adverse obstetric outcomes associated with MSAF in deliveries complicated by maternal intrapartum fever (IF). This retrospective study included all singleton pregnancies from 2014 to 2020, with intrapartum maternal fever ≥ 38°C during a trial of labor. In accordance with departmental protocol, all patients received intravenous antibiotic therapy consisting of ampicillin and gentamicin in the absence of allergies to these medications. Subsequent antibiotic therapy was adjusted based on the culture results. Antibiotic treatment was discontinued postpartum after 48h without fever. Swab cultures were obtained immediately postpartum from both the maternal and fetal sides of the placenta. Maternal and fetal outcomes, along with positive placental cultures, were compared between participants with MSAF&IF and those with clear amniotic fluid &IF (control group). In comparison to the control group (n = 1089), the MSAF&IF group (n = 264) exhibited significantly higher rates of cesarean delivery (CD) (p = 0.001), CD due to non-reassuring fetal heart rate (p = 0.001), and cord pH ≤ 7.1 (p = 0.004). Positive swab cultures from the placental maternal and fetal sides were more prevalent among the MSAF&IF group (23.1% vs. 17.6%, p = 0.041 and 29.2% vs. 22.9%, p = 0.032, respectively). Placental cultures yielding gastrointestinal pathogens and extended spectrum beta-lactamase were notably more common in the MSAF&IF group compared to controls (p = 0.023). However, there was no significant difference between groups regarding the rate of group B streptococcus positive placental cultures. Women experiencing IF and MSAF during labor face an elevated risk of CD compared to those with IF alone. The presence of MSAF heightens the risk of positive placental cultures, particularly with gastrointestinal and extended spectrum beta-lactamase pathogens.

Directed biomechanical compressive forces enhance fusion efficiency in model placental trophoblast cultures.

The syncytiotrophoblast is a multinucleated structure that arises from fusion of mononucleated cytotrophoblasts, to sheath the placental villi and regulate transport across the maternal-fetal interface. Here, we ask whether the dynamic mechanical forces that must arise during villous development might influence fusion, and explore this question using in vitro choriocarcinoma trophoblast models. We demonstrate that mechanical stress patterns arise around sites of localized fusion in cell monolayers, in patterns that match computational predictions of villous morphogenesis. We then externally apply these mechanical stress patterns to cell monolayers and demonstrate that equibiaxial compressive stresses (but not uniaxial or equibiaxial tensile stresses) enhance expression of the syndecan-1 and loss of E-cadherin as markers of fusion. These findings suggest that the mechanical stresses that contribute towards sculpting the placental villi may also impact fusion in the developing tissue. We then extend this concept towards 3D cultures and demonstrate that fusion can be enhanced by applying low isometric compressive stresses to spheroid models, even in the absence of an inducing agent. These results indicate that mechanical stimulation is a potent activator of cellular fusion, suggesting novel avenues to improve experimental reproductive modelling, placental tissue engineering, and understanding disorders of pregnancy development.

Exploring the Diagnostic and Therapeutic Significance of Thyroid Hormones in Female Infertility: A Comprehensive Narrative Review

Thyroid Hormones (TH) are essential for the healthy functioning of the female reproductive system because they regulate ovarian, uterine, and placental tissue metabolism and development. Therefore, hypo-and hyperthyroidism may result in infertility in women. Previous studies have been conducted on women with thyroid dysfunction, including prospective and retrospective studies, in-vitro and in-vivo tests for hypo-and hyperthyroidism using ovarian, uterine, and placental cell culture, and experimental animal models. In order to better understand the physiology of the reproductive system and to develop more effective therapy methods for reproductive dysfunctions that result from thyroid dysfunctions, these studies sought to shed light on the mechanisms by which TH affect reproduction. This comprehensive narrative review investigates the diagnostic and therapeutic implications of TH in female infertility. By scrutinising existing literature, the study aims to elucidate the intricate relationship between thyroid function and reproductive health in women. Such insights are crucial for enhancing diagnostic accuracy and formulating effective therapeutic interventions to address thyroid-related factors influencing female infertility

Three-Dimensional In Vitro Human Placental Organoids from Mononuclear Villous Trophoblasts or Trophoblast Stem Cells to Understand Trophoblast Dysfunction in Fetal Growth Restriction.

The placenta plays a critical role in the efficient delivery of nutrients and oxygen from mother to fetus to maintain normal fetal growth. Human placental development and function is a highly orchestrated process, which is spatially and temporally controlled by hormones and growth factors. Specialized epithelial cells called trophoblasts play key roles in placental exchange capacity, and their abnormal function and development contribute to many pregnancy complications, including fetal growth restriction (FGR), a condition in which the fetus does not reach its full growth potential in utero. Great variation in the anatomy and development of the placenta in animal model systems (in vivo) and 2D culture model systems of trophoblasts (in vitro) limits our ability to understand pregnancy disorders. Generating in vitro models that recapitulate the unique features of the human placenta has been challenging. Here, we describe detailed methods to isolate mononuclear villous trophoblasts (containing cytotrophoblasts and trophoblast stem cells) from first trimester placentae, and use both these and trophoblast stem cell populations that can be grown long term in a three-dimensional (3D) placental organoid culture system.

Identification of optimal conditions for human placental explant culture and extracellular vesicle release

Extracellular vesicles (EVs) can mediate intercellular communication, including signaling between the placenta and maternal tissues. Human placental explant culture is a versatile invitro model system to investigate placental function. We performed systematic studies in different tissue culture media types and oxygen tensions to identify a defined serum-free culture condition that supports high trophoblast viability and metabolism, as well as the release of similar populations of EVs, compared to traditional undefined conditions that contain media additives potentially contaminated with exogenous EVs. We also determined the time frame in which trophoblast viability and functionality remain optimal. Multiplex vesicle flow cytometry with classical EV and placenta-specific markers revealed three separate populations of explant-derived EVs: small CD63+ EVs; large PLAP+ EVs; and CD63-/PLAP- EVs. These culture and analytical approaches will enable invitro modeling of short-term effects of environmental perturbations associated with pregnancy complications on placental function and EV release.

Hydrogen sulfide promotes migration of trophoblast cells by a Rho GTPase mediated actin cytoskeleton reorganization

IntroductionPreeclampsia (PE) arises due to defective spiral artery remodelling which may be due to deficient migration of trophoblast cells. Migration of human endothelial cells has been shown to be promoted via Hydrogen sulphide(H2S)/Rho GTPase Rac1 axis. This novel role of H2S and its downstream processes have not yet been studied in the development and function of the placental trophoblast cells. MethodsPlacental tissues were obtained post-delivery from consented preeclamptic and normotensive mothers (n = 60). The protein expression levels of cystathionine-gamma-lyase (CSE) and cystathionine-beta-synthase (CBS) along with its downstream migratory molecules were compared in both the arms. The pro-migratory role of H2S was investigated in a first trimester placental cell line. ResultsH2S promoted the migration of trophoblast cells in a Rho GTPase dependent manner mediated by actin cytoskeleton reorganization. The reduced levels of H2S producing enzymes in the PE placentae along with decreased levels of Rho GTPases (Rac1 and Rho A) corroborate the results of PAG and AOAA treatment in down regulating the Rho GTPases in the in vitro grown placental cultures. Reduction of the migratory potential of trophoblastic cells caused due to hypoxia/reoxygenation was rescued by upregulating the H2S expression with the use of NaHS as a H2S donor. DiscussionExogenous H2S increases the migratory potential of the placental cells in culture conditions and also post hypoxia/reoxygenation injury. H2S as a gaso-transmitter holds a great potential as a therapeutic agent. Its long-term effects need to be investigated using model systems (rat/mouse) of PE following it up with clinical regulatory trials.

Ex Vivo Placental Explant Flow Culture - Mimicking the Dynamic Conditions In Utero.

The existing ex vivo placental explant culture models are primarily grounded in static culture systems using well plates. However, these models inadequately reflect the dynamic in utero setting, where the placenta encounters constant slight shear stress due to plasma or blood flow. To address this limitation, a flow culture system has been devised to bring ex vivo placental explant cultivation closer to the in utero flow conditions experienced within the maternal body. Within this approach, placental explants are cultivated in a sequence of five interconnected flow chambers. This settingmaintains physiological oxygen concentrations and a consistent flow rate. The collected data reveals that under flow conditions, the preservation of tissue morphology exhibits notable enhancement compared to conventional static methods. This innovative technique introduces a straightforward means of ex vivo placental explant culture, offering a more faithful representation of the dynamic in vivo environment. Moreover, this study introduces newpossibilities for investigating the functional dynamics of the feto-maternal interface. By embracing feasible dynamic methodologies, a deeper comprehension of placental biology is facilitated, underscoring its relevance for maternal-fetal health.

The interaction of placental micro-EVs with immune cells in vivo and in vitro.

Considerable evidence suggests that placental extracellular vesicles (EVs) interact with most types of leukocytes in vitro but in vivo biodistribution studies question whether these interactions are reflective of the situation in vivo. CellTracker Red CMTPX stained human placental micro-EVs were isolated from first trimester placental explant cultures. Equivalent amounts of micro-EVs were cultured with murine leukocytes in vitro or injected into pregnant or non-pregnant mice. After intravenous injection, on day 12.5 of gestation, major organs and blood samples were harvested 30 min or 24h post injection. We screened cryosections of the organs and confirmed that human placental EVs were specifically localised to the spleen, liver and the lungs 30 min or 24h after injection. Immunohistochemistry showed that most of the EVs interacted with macrophages in those three organs and some of them also associated with T and B lymphocytes in the spleen or endothelial cells in the lungs and liver. Flow cytometry demonstrated that there was very little interaction between circulating leukocytes and EVs in vivo. While minimal, significantly more EVs interacted with leukocytes in pregnant than nonpregnant mice. The major interaction between human placental micro-EVs and maternal leukocytes appear to be with macrophages predominantly in the splenic marginal zone, liver and lungs with little interaction between EVs and circulating leukocytes. Since marginal zone macrophages induce tolerance after phagocytosing apoptotic bodies it is likely that phagocytosis of placental EVs by marginal zone macrophages may also contribute to maternal immune tolerance.

Loss of polarity regulators initiates gasdermin-E-mediated pyroptosis in syncytiotrophoblasts.

The syncytiotrophoblast is a human epithelial cell that is bathed in maternal blood on the maternal-facing surface of the human placenta. It therefore acts as a barrier and exchange interface between the mother and fetus. Syncytiotrophoblast dysfunction is a feature of pregnancy pathologies, like preeclampsia. Dysfunctional syncytiotrophoblasts display a loss of microvilli, which is a marker of aberrant apical-basal polarization, but little data exist about the regulation of syncytiotrophoblast polarity. Atypical PKC isoforms are conserved polarity regulators. Thus, we hypothesized that aPKC isoforms regulate syncytiotrophoblast polarity. Using human placental explant culture and primary trophoblasts, we found that loss of aPKC activity or expression induces syncytiotrophoblast gasdermin-E-dependent pyroptosis, a form of programmed necrosis. We also establish that TNF-α induces an isoform-specific decrease in aPKC expression and gasdermin-E-dependent pyroptosis. Therefore, aPKCs are homeostatic regulators of the syncytiotrophoblast function and a pathogenically relevant pro-inflammatory cytokine leads to the induction of programmed necrosis at the maternal-fetal interface. Hence, our results have important implications for the pathobiology of placental disorders like preeclampsia.

Characterization of lipoproteins in human placenta and fetal circulation as well as gestational changes in lipoprotein assembly and secretion in human and mouse placentas

In the maternal circulation, apoB-containing low-density lipoproteins (LDL) and apoA1-containing high-density lipoproteins (HDL) transport lipids. The production of lipoproteins in the placenta has been suggested, but the directionality of release has not been resolved. We compared apolipoprotein concentrations and size-exclusion chromatography elution profiles of lipoproteins in maternal/fetal circulations, and in umbilical arteries/veins; identified placental lipoprotein-producing cells; and studied temporal induction of lipoprotein-synthesizing machinery during pregnancy. We observed that maternal and fetal lipoproteins are different with respect to concentrations and elution profiles. Surprisingly, concentrations and elution profiles of lipoproteins in umbilical arteries and veins were similar indicating their homeostatic control. Human placental cultures synthesized apoB100-containing LDL-sized and apoA1-containing HDL-sized particles. Immunolocalization techniques revealed that ApoA1 was present mainly in syncytiotrophoblasts. MTP, a critical protein for lipoprotein assembly, was in these trophoblasts. ApoB was in the placental stroma indicating that trophoblasts secrete apoB-containing lipoproteins into the stroma. ApoB and MTP expressions increased in placentas from the 2nd trimester to term, whereas apoA1 expression was unchanged. Thus, our studies provide new information regarding the timing of lipoprotein gene induction during gestation, the cells involved in lipoprotein assembly and the gel filtration profiles of human placental lipoproteins.Next, we observed that mouse placenta produces MTP, apoB100, apoB48 and apoA1. The expression of genes gradually increased and peaked in late gestation. This information may be useful in identifying transcription factors regulating the induction of these genes in gestation and the importance of placental lipoprotein assembly in fetal development.

Single versus dual antibiotic regimen in women with term prolonged rupture of membranes and intrapartum fever: a retrospective study.

The impact ofE. coli in causing peripartum infections has been increasing due to rising ampicillin resistance. In this study, we compared maternal and neonatal outcomes of women with prolonged rupture of membranes (ROM >18h) and intrapartum fever, according to two antibiotic regimens they received, and describe the bacterial distribution focusing on risk factors for Enterobacteriaceae-related infectious morbidity. This 10-year retrospective study of women with ROM >18h and intrapartum fever included 62 women who were treated with ampicillin and gentamicin due to suspected intraamniotic infection and 79 without these signs who were treated with ampicillin alone. The primary outcomes were endometritis and neonatal early-onset sepsis (EOS) rates. Outcomes were compared using univariate and multivariate analyses. Among women who received ampicillin alone compared with dual therapy, rates were higher of endometritis (17% vs. 3%, p<0.001), neonatal early onset sepsis (7.5% vs. 0%, p=0.03), Enterobacteriaceae positive placental swab culture (67.9% vs. 15.7%, p<0.001), and histopathological subchorionitis (25.3% vs. 8.0%, p=0.008). Over 83% of Enterobacteriaceae isolates were ampicillin-resistant. Gestational age at delivery >41 weeks, meconium at delivery, ROM >24h and treatment with a single antibiotic agent were associated with the presence of a positive Enterobacteriaceae placental swab culture. Ampicillin compared to dual treatment in women with prolonged ROM and fever might promote the growth of ampicillin-resistant Enterobacteriaceae (including E.coli) and increase risks of maternal and neonatal infectious morbidity.

Maternal elevated inflammation impairs placental fatty acids β-oxidation in women with gestational diabetes mellitus.

An adverse proinflammatory milieu contributes to abnormal cellular energy metabolism response. Gestational diabetes mellitus (GDM) is closely related to an altered maternal inflammatory status. However, its role on lipid metabolism regulation in human placenta has not yet been assessed. The aim of this study was to examine the impact of maternal circulating inflammatory mediators ([TNF]-α, [IL]-6, and Leptin) on placental fatty acid metabolism in GDM pregnancies. Fasting maternal blood and placental tissues were collected at term deliveries from 37 pregnant women (17 control and 20 GDM). Molecular approach techniques as radiolabeled lipid tracers, ELISAs, immunohistochemistry and multianalyte immunoassay quantitative analysis, were used to quantify serum inflammatory factors' levels, to measure lipid metabolic parameters in placental villous samples (mitochondrial fatty acid oxidation [FAO] rate and lipid content [Triglycerides]), and to analyze their possible relationships. The effect of potential candidate cytokines on fatty acid metabolism in ex vivo placental explants culture following C-section a term was also examined. Maternal serum IL-6, TNF-α and leptin levels were significantly increased in GDM patients compared with control pregnant women (9,9±4,5 vs. 3,00±1,7; 4,5±2,8 vs. 2,1±1,3; and 10026,7±5628,8 vs. 5360,2±2499,9 pg/ml, respectively). Placental FAO capacity was significantly diminished (~30%; p<0.01), whereas triglyceride levels were three-fold higher (p<0.01) in full-term GDM placentas. Uniquely the maternal IL-6 levels showed an inverse and positive correlation with the ability to oxidize fatty acids and triglyceride amount in placenta, respectively (r= -0,602, p=0.005; r= 0,707, p=0.001). Additionally, an inverse correlation between placental FAO and triglycerides was also found (r=-0.683; p=0.001). Interestingly, we ex vivo demonstrated by using placental explant cultures that a prolonged exposure with IL-6 (10 ng/mL) resulted in a decline in the fatty acid oxidation rate (~25%; p=0.001), along to acute increase (2-fold times) in triglycerides accumulation (p=0.001), and in lipid neutral and lipid droplets deposits. Enhanced maternal proinflammatory cytokines levels (essentially IL-6) is closely associated with an altered placental fatty acid metabolism in pregnancies with GDM, which may interfere with adequate delivery of maternal fat across the placenta to the fetus.

Obstetrical, neonatal and microbiological outcomes in laboring women with isolated fever versus suspected intraamniotic infection

The American College of Obstetricians and Gynecology recommends considering antibiotic administration for isolated intrapartum fever, but does not define the regimen. We compared obstetrical, neonatal, and microbiological outcomes between women with isolated intrapartum fever and women with suspected intraamniotic infection. This 10-year retrospective study included all laboring women with singleton gestation and body temperature ≥38.0°C, with or without other evidence of infection. Women with isolated intrapartum fever received intravenous ampicillin, while women with suspected intraamniotic infection received intravenous ampicillin plus gentamicin. The primary outcome was endometritis occurrence. Secondary outcomes comprised: 1. Maternal culture results including: positive placental and blood cultures. 2. Maternal and neonatal clinical outcomes. In total, 458 women met the inclusion criteria. Among women with isolated intrapartum fever (n=227) compared to women with suspected intraamniotic infection (n=231), incidences were higher of postpartum endometritis (8.8% vs 3.8%, p=0.03) (table 1) and early-onset neonatal sepsis (4.4% vs. 0.4%, p=0.005) (figure 1); and rates were higher of positive placental cultures (63.9% vs. 46.3%, p< 0.001), especially ampicillin-resistant E. coli (48.9% vs. 35.4%, p=0.033). The rate of Group B streptococci positive placental cultures was similar between the groups. Women with isolated intrapartum fever, who were treated with ampicillin only, had worse maternal and neonatal outcomes than women with suspected intraamniotic infection who received ampicillin and gentamicin. Administration of ampicillin as a sole agent might promote the growth of ampicillin-resistant Enterobacteriaceae, especially E. coli, in placental cultures, and might result in endometritis and early-onset neonatal sepsis. The combined treatment with ampicillin and gentamicin that is given to women with suspected intraamniotic infection should be considered also for women with isolated intrapartum fever.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Placental uptake and metabolism of 25(OH)vitamin D determine its activity within the fetoplacental unit

Brief summary: Using placental perfusion, placental fragment culture and primary term human cytotrophoblast culture experiments, the authors signify the relationship between maternal vitamin D, placental vitamin D metabolism and fetal vitamin D exposure.

Ex vivo toxicity of E-cigarette constituents on human placental tissues

Globally, ∼50 % of women smoke during pregnancy and the prevalence of vaping is increasing among women of reproductive age. However, the health effects of vaping during pregnancy are largely unknown. This study examined the effects of e-cig constituents alone and in combination (propylene glycol [PG], vegetable glycerin [VG], and nicotine) on human placental tissue viability (MTT assay) and immunoassayed levels of placenta-derived biomarkers, i.e., 8-isoprostane (8-IsoP), heme oxygenase-1 (HO-1), interleukin-6 (IL-6), β-estradiol (E2), progesterone (P4), allopregnanolone (AP), and brain-derived neurotrophic factor (BDNF). Placental explant cultures were exposed ex vivo for 24 h to media-containing either nicotine (0–5000 nM), PG/VG (0–8 % v/v at 50/50 ratio), or a combination of both. No effects on tissue viability were observed at PG/VG concentrations < 8 % (v/v), while viability significantly reduced at PG/VG concentrations ≥ 10 % (v/v); biomarker studies employed only non-cytotoxic doses. Exposure to PG/VG decreased levels of 8-IsoP, IL-6, and E2, and treatment with 2 % or 8 % PG/VG significantly reduced HO-1 levels, compared to non-treated controls. Exposure to nicotine alone at 2,500 nM and 5,000 nM reduced MTT activity by 20 % (P = 0.04) and 70 % (P < 0.001), respectively, and significantly increased (P < 0.001) levels of HO-1 and BDNF, compared to controls. Treatment with nicotine alone and in combination with PG/VG reduced IL-6 and E2 levels. Interestingly, nicotine-induced toxicity was attenuated by PG/VG addition to nicotine-treated groups. These studies demonstrate that e-cig constituents negatively impact the human placenta and alters production of critical placental biomarkers, suggesting that vaping is an unsafe alternative for pregnant women or their unborn fetus.

The correlation between placental histology and microbiologic infection in the diagnosis of chorioamnionitis in preterm delivery

IntroductionThis study sought to investigate the correlation between histologically proven chorioamnionitis and placental bacteriologic infection in preterm births. MethodsWomen who gave birth before 34 + 0 weeks’ gestation at a tertiary medical center between the years 2018–2019 were identified by a database review. Data was collected on clinical characteristics and findings on placental histology, cultures, and polymerase chain reaction. The correlation between histologically confirmed chorioamnionitis and bacteriologic infection was evaluated. ResultsOf 183 placentas included in the study, 88 (48.1%) were histologically positive for chorioamnionitis and 95 (51.9%) were negative. Baseline characteristics were similar in the patients with and without chorioamnionitis. Concordance rates between the histology and microbiology results in the two groups were 51.1% and 64.2%, respectively. Similar types of bacterial microorganisms were isolated in both groups, though at different rates. On chi-square analysis of association, a positive microbiological study had a sensitivity of 51.1%, specificity of 64.2%, and positive predictive value of 56.9% for predicting histologically confirmed chorioamnionitis. Histologically confirmed chorioamnionitis was associated with higher antepartum white blood cell count (14.2 ± 4.6 vs 12.3 ± 3.3 K/μL; p = 0.01), higher rate of clinically suspected chorioamnionitis (10.2% vs 1.1%, p = 0.02), and higher rate of neonatal adverse composite outcome (36.4% vs. 22.1%, p = 0.009). DiscussionThe correlation between histologic and bacteriologic placental findings in the setting of early premature delivery is not high, nor is the clinical yield of placental bacteriology. The discordant results might be explained by early stage of bacterial infection, hard-to-cultivate bacterial species, noninfectious conditions, or contamination of the placental surfaces during passage through the vaginal tract.

Characteristics of the effect of exosomes isolated from donor plasma and placenta-derived mesenchymal stromal cell-conditioned medium on the paracrine secretion of human peripheral blood mononuclear cells

Extracellular small vesicles – exosomes, attract the attention of researchers as a promising tool for regulating intercellular communication. At the same time, the therapeutic effects achieved through the use of mesenchymal stem cells (MSCs) are traditionally considered by medicine as a time-tested, multi-vector strategy for the treatment of various pathologies. In particular, in addition to the application of MSCs directly, it is important to study the products of their secretion. Aim. To study characteristics of the influence of exosomes isolated from blood plasma of healthy donors and conditioned medium of placental mesenchymal stromal cell (MSC) culture on paracrine secretion of peripheral blood mononuclear cells (PBMCs) in patients with chronic heart failure (CHF) in vitro. Materials and methods. The characteristics of paracrine secretion of PBMCs in patients with CHF by the content of proteins VEGF-A, MCP-1, ICAM-1 in their culture medium were studied in two directions: under the influence of exosomes isolated from plasma of healthy donors and exosomes isolated from placental MSC culture medium. Results. Incubation of PBMCs with plasma exosomes increased VEGF-A secretion in the group of healthy donors by 2.73 times (P ≤ 0.05), in patients with CHF – by 2 times (P ≤ 0.05); but there were a multidirectional effect on the content of ICAM-1 protein: it was 1.8 times (P ≤ 0.05) increased in the group of donors and 1.4 times (P ≤ 0.05) decreased in the group of CHF patients; MCP-1 secretion was insignificantly 10 % reduced in the donor group and did not change significantly in patients. Incubation of РВМС with exosomes isolated from MSC conditioned medium did not cause significant changes in paracrine secretion of PBMCs: there was a decrease in secretion of VEGF-A by 25 %, ICAM-1 by 17 %, MCP-1 by 22 % in the group of healthy volunteers; secretion of these proteins was 19.7 %, 22.0 % and 25.0 % decreased, respectively, in the group of CHF patients. The effects observed in the incubation of PBMCs with exosomes isolated from blood plasma of healthy donors and conditioned medium of placental MSC culture have provided valuable information for the design of future studies in this area of cell biology. Conclusions. Our studies have demonstrated in vitro the effects of exosomes isolated from donor plasma and conditioned medium on the functional properties of human PBMCs.

Usutu Virus Infects Human Placental Explants and Induces Congenital Defects in Mice.

Usutu virus (USUV) is a neurotropic mosquito-borne flavivirus that has dispersed quickly in Europe these past years. This arbovirus mainly follows an enzootic cycle involving mosquitoes and birds, but can also infect other mammals, causing notably sporadic cases in humans. Although it is mainly asymptomatic or responsible for mild clinical symptoms, USUV has been associated with neurological disorders, such as encephalitis and meningoencephalitis, highlighting the potential health threat of this virus. Among the different transmission routes described for other flaviviruses, the capacity for some of them to be transmitted vertically has been demonstrated, notably for Zika virus or West Nile virus, which are closely related to USUV. To evaluate the ability of USUV to replicate in the placenta and gain access to the fetus, we combined the use of several trophoblast model cell lines, ex vivo human placental explant cultures from first and third trimester of pregnancy, and in vivo USUV-infected pregnant mice. Our data demonstrate that human placental cells and tissues are permissive to USUV replication, and suggest that viral transmission can occur in mice during gestation. Hence, our observations suggest that USUV could be efficiently transmitted by the vertical route.

Inflammatory responses in the placenta upon SARS-CoV-2 infection late in pregnancy

SummaryThe effect of SARS-CoV-2 infection on placental function is not well understood. Analysis of placentas from women who tested positive at delivery showed SARS-CoV-2 genomic and subgenomic RNA in 22 out of 52 placentas. Placentas from two mothers with symptomatic COVID-19 whose pregnancies resulted in adverse outcomes for the fetuses contained high levels of viral Alpha variant RNA. The RNA was localized to the trophoblasts that cover the fetal chorionic villi in direct contact with maternal blood. The intervillous spaces and villi were infiltrated with maternal macrophages and T cells. Transcriptome analysis showed an increased expression of chemokines and pathways associated with viral infection and inflammation. Infection of placental cultures with live SARS-CoV-2 and spike protein-pseudotyped lentivirus showed infection of syncytiotrophoblast and, in rare cases, endothelial cells mediated by ACE2 and Neuropilin-1. Viruses with Alpha, Beta, and Delta variant spikes infected the placental cultures at significantly greater levels.

Procyanidin B2 ameliorates endothelial dysfunction and impaired angiogenesis via the Nrf2/PPARγ/sFlt-1 axis in preeclampsia

Preeclampsia is a severe complication of pregnancy characterised by variable degrees of placental malperfusion. A growing body of evidence indicates that soluble endoglin and soluble fms-like tyrosine kinase-1 (sFlt-1) play important pathophysiological roles in preeclampsia, causing endothelial dysfunction, hypertension, and multiorgan injury. A drug that is safe in pregnancy and inhibits placental sFlt-1 and soluble endoglin secretion would be an attractive treatment strategy for preeclampsia. Procyanidin B2, a bioactive food compound, has been reported to exert multiple beneficial functions. Placental explant cultures in vitro are useful for studying tissue functions including release of secretory components, pharmacology, toxicology, and disease processes. The reduced uterine perfusion pressure (RUPP) rat model has been widely used as a model of preeclampsia. We aimed to investigate the effect of procyanidin B2 on preeclampsia via using placental explant cultures and RUPP rat model. In this study, we demonstrated that procyanidin B2 reduced soluble endoglin and sFlt-1 secretion from human umbilical vein endothelial cells (HUVECs), primary trophoblasts, and placental explants from preeclamptic pregnancies. Moreover, procyanidin B2 alleviated endothelial dysfunction and impaired angiogenesis induced by sFlt-1, including increasing the migration, invasion and angiogenesis of endothelial cells and decreasing the expression of vascular cell adhesion molecule-1 (VCAM-1) and leukocyte adhesion on HUVECs. In addition, procyanidin B2 promoted nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation and induced peroxisome proliferator-activated receptor γ (PPARγ) expression in primary placental tissues and endothelial cells. Importantly, Nrf2 specifically binds to the PPARγ promoter region (-1227/-1217) and enhances its transcriptional activity. Procyanidin B2 inhibits sFlt-1 secretion via the Nrf2/PPARγ axis. In the RUPP rat model of preeclampsia, procyanidin B2 attenuated RUPP-induced maternal angiogenic imbalance, hypertension and improved placental and foetal weight. Taken together, our results demonstrate that procyanidin B2 inhibits sFlt-1 secretion and ameliorates endothelial dysfunction and impaired angiogenesis via the Nrf2/PPARγ axis in preeclampsia. Procyanidin B2 may be a novel therapeutic agent for treatment of preeclampsia.