eNOS/iNOS and endoplasmic reticulum stress-induced apoptosis in the placentas of patients with preeclampsia

Mesenchymal stem cells and their exosomes: a novel approach to skin regeneration via signaling pathways activation

Accelerating wound healing is a crucial objective in surgical and regenerative medicine. The wound healing process involves three key stages: inflammation, cell proliferation, and tissue repair. Mesenchymal stem cells (MSCs) have demonstrated significant therapeutic potential in promoting tissue regeneration, particularly by enhancing epidermal cell migration and proliferation. However, the precise molecular mechanisms underlying MSC-mediated wound healing remain unclear. This review highlights the pivotal role of MSCs and their exosomes in wound repair, with a specific focus on critical signaling pathways, including PI3K/Akt, WNT/β-catenin, Notch, and MAPK. These pathways regulate essential cellular processes such as proliferation, differentiation, and angiogenesis. Moreover, in vitro and in vivo studies reveal that MSCs accelerate wound closure, enhance collagen deposition, and modulate immune responses, contributing to improved tissue regeneration. Understanding these mechanisms provides valuable insights into MSC-based therapeutic strategies for enhancing wound healing.

Current Approaches and Innovations in Managing Preeclampsia: Highlighting Maternal Health Disparities

Preeclampsia (PE) is a major cause of maternal mortality and morbidity, affecting 3-6% of pregnancies worldwide and ranking among the top six causes of maternal deaths in the U.S. PE typically develops after 20 weeks of gestation and is characterized by new-onset hypertension and/or end-organ dysfunction, with or without proteinuria. Current management strategies for PE emphasize early diagnosis, blood pressure control, and timely delivery. For prevention, low-dose aspirin (81 mg/day) is recommended for high-risk women between 12 and 28 weeks of gestation. Magnesium sulfate is also advised to prevent seizures in preeclamptic women at risk of eclampsia. Emerging management approaches include antiangiogenic therapies, hypoxia-inducible factor suppression, statins, and supplementation with CoQ10, nitric oxide, and hydrogen sulfide donors. Black women are at particularly high risk for PE, potentially due to higher rates of hypertension and cholesterol, compounded by healthcare disparities and possible genetic factors, such as the APOL1 gene. This review explores current and emerging strategies for managing PE and addresses the underlying causes of health disparities, offering potential solutions to improve outcomes.

A stress paradox: the dual role of the unfolded protein response in the placenta

The placenta is a temporary organ that forms during pregnancy and is essential for fetal development and maternal health. As an endocrine organ, proper placental function requires continual production, folding, and transport of proteins and lipids. Central to these processes is the endoplasmic reticulum (ER), a dynamic organelle responsible for maintaining cellular protein and lipid synthesis and processing. ER stress occurs when there is an accumulation of unfolded or misfolded proteins, which triggers the activation of cellular pathways collectively called the unfolded protein response. Unfolded protein response pathways act to alleviate the misfolded protein burden and restore ER homeostasis, or if unresolved, initiate cell death. While prolonged ER stress has been linked to deficient placental function and adverse pregnancy outcomes, basal activation of unfolded protein response pathways is required for placental development and function. This review explores the importance of ER homeostasis in placental development and function, examining how disruptions in ER stress responses may contribute to adverse pregnancy outcomes.

Understanding the impact of placental oxidative and nitrative stress in pregnancies complicated by fetal growth restriction

Fetal growth restriction (FGR) impacts approximately 10 % of all pregnancies worldwide and is associated with major adverse effects on fetal health in both the short- and long-term [1]. FGR most commonly arises as a result of impaired placentation, occurring in up to 60 % of cases in developed countries [2]. This narrative review outlines the impact of defective placentation on the placenta, focusing on redox imbalance, how this leads to placental oxidative and nitrative stress, and the implications of these stressors on placental nutrient transfer, premature replicative senescence, and trophoblast cell death. Furthermore, this review highlights the pivotal role of antioxidants in protecting against oxidative and nitrative damage by reducing the burden of reactive species. We explore how targeting antioxidants in pregnancy provides a promising strategy for preventing or treating FGR, to ultimately reduce the devastating burden of FGR on infant health.

Alteration in sB7-H4 Serum Levels and Placental Biomarker Expression after Therapeutic Plasma Exchange in Early-Onset Preeclampsia Patients

Therapeutic plasma exchange (TPE) is a widely used treatment for numerous diseases including pregnancy-related conditions. Our prior study on 20 early-onset preeclampsia patients undergoing TPE revealed a significant extension in pregnancy duration and reduced serum levels of sFlt-1, sFlt-1/PlGF, and sEndoglin. Here, we investigated the impact of TPE on serum sB7-H4, an immunological checkpoint molecule, and placental proteins (Flt-1, Eng, B7-H4, iNOS, TNF-α) in TPE-treated early-onset preeclampsia patients (N = 12, 23 + 2-28 + 5 weeks), conventionally treated counterparts (N = 12, 23 + 5-30 weeks), and gestational age-matched controls (N = 8, 22 + 4-31 + 6 weeks). Immunoblotting, ELISA, and co-immunohistochemistry were used for biomarker analysis, including placental inflammation factors (iNOS, TNF-α). The results showed that TPE extended pregnancy by a median of 6.5 days in this cohort of early-onset preeclampsia. Serum sB7-H4, sFlt-1, and sEndoglin levels decreased, along with reduced expression of their membrane-bound proteins in placental tissue upon TPE treatment. Moreover, TPE-treated patients displayed reduced placental inflammation compared to preeclampsia patients receiving standard-of-care treatment. In conclusion, TPE may improve pregnancy outcomes in early-onset preeclampsia by lowering circulating levels of sB7-H4, sFlt-1, and sEndoglin, as well as reducing placental inflammation. This translational approach holds promise for enhancing placental function and extending gestation in high-risk pregnancies including very preterm PE or HELLP cases.

Proteomic Analysis Reveals Differential Protein Expression in Placental Tissues of Early-Onset Preeclampsia Patients

Preeclampsia, a significant cause of maternal and perinatal morbidity and mortality, remains poorly understood, in terms of its pathogenesis. This study aims to uncover novel and effective biomarkers for preeclampsia by conducting a comparative analysis of differential proteins in placentas from early onset preeclampsia (EOPE) and normal pregnancies. Utilizing tandem mass tag (TMT)-based quantitative proteomics, we identified differentially expressed proteins in placental tissues from 15 EOPE patients and 15 normal pregnant women. These proteins were subsequently validated by using parallel reaction monitoring (PRM). Our analysis revealed a total of 59 differentially expressed proteins, with 25 up-regulated and 34 down-regulated proteins in EOPE placental tissues compared to those from normal pregnancies. Validation through PRM confirmed the differential expression of 6 proteins. Our findings suggest these 6 proteins could play crucial roles in the pathogenesis of EOPE, highlighting the potential involvement of the estrogen signaling pathway and dilated cardiomyopathy (DCM) pathway in the development of preeclampsia. The data were deposited with the ProteomeXchange Consortium via the iProX partner repository with the identifier PXD055025.

Epigallocatechin gallate (EGCG) alleviates inflammation and endothelial dysfunction and improves pregnancy outcomes in preeclampsia (PE)-like rats via eNOS/Nrf2/HO-1 pathway

BACKGROUND AND PURPOSE

Epigallocatechin gallate (EGCG), a natural antioxidant, has shown protective effect in many diseases. We explore the effect and potential regulatory mechanisms of EGCG in preeclampsia (PE)-like rats.

METHODS AND MATERIALS

PE was mimicked in pregnant rats. EGCG was orally administered at a dosage of 25(Low, L) or 50 mg/kg (High, H) from gestational day (GD) 6-17. The blood pressure signatures, heart rates were monitored. The 24-h proteinuria and serum were analyzed. On GD 18, rats were sacrificed, and pups and placentas were weighed. Kidneys and placentas were analyzed using immunohistochemistry (IHC) and hematoxylin-eosin staining (H&E). Placentas were examined using western blot for sFlt1, eNOS, Nrf2, HO-1, SLC7A11. MDA, GSH, GPx and Fe2+ were measured.

RESULTS

EGCG inhibits systolic blood pressure, BUN, CREA, ALT, AST, UA and proteinuria levels in PE-like rats. EGCG enhances the pup weight and crown-rump length and reduces the rate of fetus growth restriction in PE group. Endothelial dysfunction and infiltration of inflammatory cells were found in kidney cortex and placenta tissues in PE group and were inhibited by EGCG treatment. sFlt1 was activated in placentas in PE group and inhibited by EGCG while eNOS/Nrf2/HO-1 were inhibited in PE group and restored by EGCG. MDA and Fe concentrations were elevated in PE group and reduced by EGCG while the GSH level, SLC7A11 and the GPx activity were inhibited in PE group and restored by EGCG.

CONCLUSION

EGCG alleviates inflammation, endothelial dysfunction and placental ferroptosis, improves pregnancy outcomes in PE-like rats via eNOS/Nrf2/HO-1.

CircRNA_0088196 Regulates Trophoblast Proliferation and Apoptosis in Preeclampsia Through the miR-379-5p/HSPA5 Axis

Existing research has confirmed the dysregulation of circular RNA (circRNA) in a wide variety of human diseases. Thus, in this study, we explored the potential mechanism of circRNA_0088196 in preeclampsia (PE). We performed quantitative real-time PCR to examine circRNA_0088196 expression and verified the function of circRNA_0088196 in vitro using CCK-8, TUNEL, flow cytometry, and Western blotting analyses. Additionally, we studied the mechanism using dual-luciferase reporter gene experiments. The results of our research revealed the up-regulation of circRNA_0088196 in PE patients' placentas and Heat Shock 70 kDa Protein 5 (HSPA5)-stimulated trophoblast (HTR-8/SVneo) cells. An investigation of the mechanism also showed that there was a binding between miR-379-5p and circRNA_0088196. Additionally, circRNA_0088196 inhibited HTR-8/SVneo cell proliferation and promoted cell apoptosis via the miR-337-3p/HSPA5 axis, thereby facilitating PE. In vivo experiments indicated that circRNA_0088196 regulated HTR-8/SVneo cell production through miR-379-5p. Overall, the findings of this study illustrate that circRNA_0088196 interference promotes cell apoptosis and inhibits HTR-8/SVneo proliferation via the miR-379-5p/HSPA5 axis, thereby accelerating the development of PE.

Regulation of renal nitric oxide and eNOS/iNOS expression by tadalafil participates in the mitigation of amphotericin B-induced renal injury: Down-regulation of NF-κB/iNOS/caspase-3 signaling

Amphotericin B (AmB)-induced acute kidney injury (AKI) is a common health problem having an undesirable impact on its urgent therapeutic utility for fatal systemic fungal infections. Tadalafil (TAD), a phosphodiesterase-5 (PDE-5) inhibitor, has been observed to have a wide range of pharmacological actions, including nephroprotection. The study's objective was to examine the possible underlying protective mechanism of TAD against AmB-induced nephrotoxicity. Experimentally, animals were divided randomly into four groups: control, TAD (5 mg/kg/day; p.o.), AmB (18.5 mg/kg/day; i.p.), and TAD+AmB groups. Sera and tissue samples were processed for biochemical, molecular, and histological analyses. The biochemical investigations showed that TAD significantly ameliorated the increase of kidney function biomarkers (creatinine, urea, CysC, KIM-1) in serum, renal nitric oxide (NO), lipid peroxidation (MDA), and inflammatory cytokines (TNF-α, IL-6) in AmB-treated rats. Meanwhile, TAD significantly retarded AmB-induced decrease in serum magnesium, sodium, potassium, and renal glutathione content. Molecular analysis revealed that TAD reduced AmB-induced imbalance in the protein expression of eNOS/iNOS, which explains its regulatory effect on renal NO content. These results were also supported by the down-regulation of nuclear NF-κB p65 and cleaved caspase-3 protein expressions, as well as the improvement of histological features by TAD in AmB-treated rats. Therefore, it can be suggested that TAD could be a promising candidate for renoprotection against AmB-induced AKI. That could be partly attributed to its regulatory effect on renal eNOS/iNOS balance and NO, the inhibition of NF-κB p65 nuclear translocation, its downstream inflammatory cytokines and iNOS, and ultimately the inhibition of caspase-3-induced renal apoptosis.

Phenylbutyric acid inhibits hypoxia-induced trophoblast apoptosis and autophagy in preeclampsia via the PERK/ATF-4/CHOP pathway

Preeclampsia (PE) is a common pregnancy complication with a high mortality rate. Abnormally activated endoplasmic reticulum stress (ERS) is believed to be responsible for the destruction of key placental cells-trophoblasts. Phenylbutyric acid (4-PBA), an ERS inhibitor, is involved in regulating the development of ERS-related diseases. At present, how 4-PBA affects trophoblasts and its mechanisms is still unclear. In this study, PE cell models were established by stimulating HTR-8/SVneo cells with hypoxia. To verify the underlying mechanisms of 4-PBA on PE, CCT020312, an activator of PERK, was also used. The results showed that 4-PBA restored hypoxia-induced trophoblast viability, inhibited HIF-1α protein expression, inflammation, and PERK/ATF-4/CHOP pathway. Hoechst 33342 staining and flow cytometry results confirmed that 4-PBA decreased hypoxia-induced apoptosis in trophoblasts. The results of the JC-1 analysis and apoptosis initiation enzyme activity assay also demonstrated that 4-PBA inhibited apoptosis related to the mitochondrial pathway. Furthermore, by detecting autophagy in trophoblasts, an increased number of autophagic vesicles, damaged mitochondria, enhanced dansylcadaverine fluorescence, enhanced levels of autophagy proteins Beclin-1, LC3II, and decreased p62 were seen in hypoxia-stimulated cells. These changes were reversed by 4-PBA. Furthermore, it was observed that CCT020312 reversed the effects of 4-PBA on the viability, apoptosis, and autophagosome number of hypoxia-induced trophoblasts. In summary, 4-PBA reduces autophagy and apoptosis via the PERK/ATF-4/CHOP pathway and mitochondrial pathway, thereby restoring the viability of hypoxic trophoblasts. These findings provide a solid evidence base for the use of 4-PBA in PE treatment and guide a new direction for improving the outcomes of patients with PE.

Inhibition of the endoplasmic reticulum stress-associated IRE-1 pathway alleviates preterm birth

BACKGROUND

Premature birth (PTB) remains a major global health concern due to its association with neonatal morbidity and mortality. The unfolded protein response (UPR) within the endoplasmic reticulum (ER) is tightly regulated by Inositol-requiring enzyme type 1 (IRE-1), a pivotal cellular modulator. This study seeks to elucidate the role of the ER stress (ERS)-related IRE-1 pathway in PTB.

METHODS

Human placental trophoblast cells HTR8/Svneo were exposed to the ER-stress inducer tunicamycin (TM). The expression of IRE-1 and ERS-associated proteins ATF6, GRP78, and XBP-1 was assessed in placental tissues and TM-treated cells. Cellular viability, migration, invasion, and apoptosis were evaluated through a series of experimental assays. Additionally, various methods were employed to assess and verify the activation of autophagy, using the autophagy marker, microtubule-associated protein 1A/1B-light chain 3 (LC3). Additionally, TUDCA (an ERS inhibitor) was used to assess its potential to counteract the TM-induced cell effects.

RESULTS

Elevated levels of ATF6, GRP78, and XBP-1 were observed in PTB tissues and cells. TM treatment substantially reduced cell viability, migration, and invasion while promoting apoptosis. Treatment with TUDCA (an ERS inhibitor) counteracted the effects of TM on the cells. Furthermore, we identified an overexpression of IRE-1 in PTB tissues and cells and its knockdown enhanced cell viability, migration, and invasion while suppressed apoptosis and autophagy under TM stimulation. Notably, IRE-1 was found to modulate the activity of the IRE-1/XBP1/CHOP signaling pathway in TM-treated cells.

CONCLUSION

The upregulation of IRE-1 in PTB placental tissues is implicated in the pathogenesis of PTB. Importantly, inhibiting the ERS-associated IRE-1/XBP1/CHOP pathway may be a good strategy in mitigating PTB.

MicroRNA-322 overexpression reduces neural tube defects in diabetic pregnancies

BACKGROUND

Hyperglycemia from pregestational diabetes mellitus induces neural tube defects in the developing fetus. Folate supplementation is the only effective way to prevent neural tube defects; however, some cases of neural tube defects are resistant to folate. Excess folate has been linked to higher maternal cancer risk and infant allergy. Therefore, additional interventions are needed. Understanding the mechanisms underlying maternal diabetes mellitus-induced neural tube defects can identify potential targets for preventing such defects. Despite not yet being in clinical use, growing evidence suggests that microRNAs are important intermediates in embryonic development and can serve as both biomarkers and drug targets for disease intervention. Our previous studies showed that maternal diabetes mellitus in vivo activates the inositol-requiring transmembrane kinase/endoribonuclease 1α (IRE1α) in the developing embryo and that a high glucose condition in vitro reduces microRNA-322 (miR-322) levels. IRE1α is an RNA endonuclease; however, it is unknown whether IRE1α targets and degrades miR-322 specifically or whether miR-322 degradation leads to neural tube defects via apoptosis. We hypothesize that IRE1α can inhibit miR-322 in maternal diabetes mellitus-induced neural tube defects and that restoring miR-322 expression in developing neuroepithelium ameliorates neural tube defects.

OBJECTIVE

This study aimed to identify potential targets for preventing maternal diabetes mellitus-induced neural tube defects and to investigate the roles and relationship of a microRNA and an RNA endonuclease in mouse embryos exposed to maternal diabetes mellitus.

STUDY DESIGN

To determine whether miR-322 reduction is necessary for neural tube defect formation in pregnancies complicated by diabetes mellitus, male mice carrying a transgene expressing miR-322 were mated with nondiabetic or diabetic wide-type female mice to generate embryos with or without miR-322 overexpression. At embryonic day 8.5 when the neural tube is not yet closed, embryos were harvested for the assessment of 3 miR-322 transcripts (primary, precursor, and mature miR-322), tumor necrosis factor receptor-associated factor 3 (TRAF3), and neuroepithelium cell survival. Neural tube defect incidences were determined in embryonic day 10.5 embryos when the neural tube should be closed if there is no neural tube defect formation. To identify which miR-322 transcript is affected by maternal diabetes mellitus and high glucose conditions, 3 miR-322 transcripts were assessed in embryos from dams with or without diabetes mellitus and in C17.2 mouse neural stem cells treated with different concentrations of glucose and at different time points. To determine whether the endonuclease IRE1α targets miR-322, small interfering RNA knockdown of IRE1α or overexpression of inositol-requiring transmembrane kinase/endoribonuclease 1α by DNA plasmid transfection was used to determine the effect of IRE1α deficiency or overexpression on miR-322 expression. RNA immunoprecipitation was performed to reveal the direct targets of inositol-requiring transmembrane kinase/endoribonuclease 1α.

RESULTS

Maternal diabetes mellitus suppressed miR-322 expression in the developing neuroepithelium. Restoring miR-322 expression in the neuroepithelium blocked maternal diabetes mellitus-induced caspase-3 and caspase-8 cleavage and cell apoptosis, leading to a neural tube defect reduction. Reversal of maternal diabetes mellitus-inhibited miR-322 via transgenic overexpression prevented TRAF3 up-regulation in embryos exposed to maternal diabetes mellitus. Activated IRE1α acted as an endonuclease and degraded precursor miR-322, resulting in mature miR-322 reduction.

CONCLUSION

This study supports the crucial role of the IRE1α-microRNA-TRAF3 circuit in the induction of neuroepithelial cell apoptosis and neural tube defect formation in pregnancies complicated by diabetes mellitus and identifies IRE1α and miR-322 as potential targets for preventing maternal diabetes mellitus-induced neural tube defects.

Protein Misfolding in Pregnancy: Current Insights, Potential Mechanisms, and Implications for the Pathogenesis of Preeclampsia

Protein misfolding disorders are a group of diseases characterized by supra-physiologic accumulation and aggregation of pathogenic proteoforms resulting from improper protein folding and/or insufficiency in clearance mechanisms. Although these processes have been historically linked to neurodegenerative disorders, such as Alzheimer's disease, evidence linking protein misfolding to other pathologies continues to emerge. Indeed, the deposition of toxic protein aggregates in the form of oligomers or large amyloid fibrils has been linked to type 2 diabetes, various types of cancer, and, in more recent years, to preeclampsia, a life-threatening pregnancy-specific disorder. While extensive physiological mechanisms are in place to maintain proteostasis, processes, such as aging, genetic factors, or environmental stress in the form of hypoxia, nutrient deprivation or xenobiotic exposures can induce failure in these systems. As such, pregnancy, a natural physical state that already places the maternal body under significant physiological stress, creates an environment with a lower threshold for aberrant aggregation. In this review, we set out to discuss current evidence of protein misfolding in pregnancy and potential mechanisms supporting a key role for this process in preeclampsia pathogenesis. Improving our understanding of this emerging pathophysiological process in preeclampsia can lead to vital discoveries that can be harnessed to create better diagnoses and treatment modalities for the disorder.

Endoplasmic reticulum stress impairs trophoblast syncytialization through upregulation of HtrA4 and causes early-onset preeclampsia

OBJECTIVE

Syncytiotrophoblasts form via mononuclear cytotrophoblast fusion during placentation and play a critical role in maternal-fetal communication. Impaired syncytialization inevitably leads to pregnancy-associated complications, including preeclampsia. Endoplasmic reticulum stress (ERS) is reportedly linked with preeclampsia, but little is known about its association with syncytialization. High temperature requirement factor A4 (HtrA4), a placental-specific protease, is responsible for protein quality control and placental syncytialization. This study aimed to investigate the relationship among HtrA4, ERS, and trophoblast syncytialization in the development of early-onset preeclampsia (EO-PE).

METHODS

HtrA4 expression and ERS in preeclamptic placentas and control placentas were analyzed by Western blotting and qRT-PCR. HtrA4 and ERS localization in placentas was determined by immunohistochemistry and immunofluorescence. BeWo cells were used to stimulate the effects of HtrA4 and ERS on syncytialization.

RESULTS

HtrA4 expression was upregulated in EO-PE and positively correlated with ERS. HtrA4 activity was increased in preeclampsia. Under normoxia, HtrA4 overexpression in BeWo cells did not alter the ERS level. In addition, treatment with hypoxia/reoxygenation (H/R) or an ERS inducer increased HtrA4 expression. HtrA4 upregulation suppressed the levels of syncytin-2 and β-HCG in the presence of forskolin (FSK), and this change was exaggerated after ERS activation. In addition, treatment with an ERS inhibitor markedly suppressed FSK-treated cell fusion in a manner related to downregulation of HtrA4 expression.

CONCLUSION

Our results suggest that ERS enables syncytialization of placental development by upregulating HtrA4, but that excessive HtrA4 expression and preexisting ERS impair syncytialization and cause EO-PE.

Sodium Nitrite Attenuates Reduced Activity of Vascular Matrix Metalloproteinase-2 and Vascular Hyper-Reactivity and Increased Systolic Blood Pressure Induced by the Placental Ischemia Model of Preeclampsia in Anesthetized Rats

Preeclampsia is a maternal hypertension disorder associated with vascular dysfunction and fetal and placental growth restrictions. Placental ischemia is suggested as the primary trigger of preeclampsia-associated impairments of both endothelium-derived nitric oxide (NO) and the vascular activity of extracellular matrix metalloproteinase-2 (MMP-2). Reduced uteroplacental perfusion pressure (RUPP) is a placental ischemia model of preeclampsia. Reduction of sodium nitrite to NO may occur during ischemic conditions. However, sodium nitrite effects in the RUPP model of preeclampsia have not yet been investigated. Pregnant rats were divided into four groups: normotensive pregnant rats (Norm-Preg), pregnant rats treated with sodium nitrite (Preg + Nitrite), preeclamptic rats (RUPP), and preeclamptic rats treated with sodium nitrite (RUPP + Nitrite). Maternal blood pressure and fetal and placental parameters were recorded. Vascular function, circulating NO metabolites, and the gelatinolytic activity of vascular MMP-2 were also examined. Sodium nitrite attenuates increased blood pressure, prevents fetal and placental weight loss, counteracts vascular hyper-reactivity, and partially restores NO metabolites and MMP-2 activity. In conclusion, sodium nitrite reduction to NO may occur during RUPP-induced placental ischemia, thereby attenuating increased blood pressure, fetal and placental growth restriction, and vascular hyper-reactivity associated with preeclampsia and possibly restoring NO and MMP-2 activity, which underlie the blood pressure-lowering effects.

Placental expression of striatin & endothelial nitric oxide synthase in women with & without pre-eclampsia

BACKGROUND & OBJECTIVES

Striatin is a multi-domain scaffolding protein essential for activating endothelial nitric oxide synthase (eNOS). However, its role in pre-eclampsia remains use explored. Hence, this study aimed to investigate the association between striatin and eNOS in regulating nitric oxide (NO) production in the placenta of women with and without pre-eclampsia.

METHODS

Forty pregnant women each without (controls) and with pre-eclampsia (cases) were enrolled in the study. Blood striatin and NO concentrations were detected by the ELISA. Protein expression of striatin, phosphorylated eNOS (peNOS), inducible NOS (iNOS) and phosphorylated NF-κB were measured in the placental tissues by Western blot. Twenty four hour urinary protein and serum urea, uric acid and creatinine were analyzed as an autoanalyzer. Placental histology was analyzed by haematoxylin and eosin staining. Results: Compared to normotensive pregnant women, the levels of serum NO and striatin were decreased in pre-eclamptic women. The protein expression of striatin and peNOS was significantly reduced (P<0.05) while p65NF-κB and iNOS were upregulated considerably (P<0.05) in the placenta of cases compared to controls.

INTERPRETATION & CONCLUSIONS

Our results show for the first time that decreased striatin expression was associated with decreased peNOS protein expression in the placental tissue of pre-eclamptic women. Interestingly, no significant difference was found in blood striatin or NO levels between controls and cases. Thus, therapies that improve placental striatin expression are attractive possibilities, both for prevention as well as treatment of endothelial dysfunction in pre-eclampsia.

Emerging Roles of Endocannabinoids as Key Lipid Mediators for a Successful Pregnancy

In recent years, Cannabis use/misuse for treating pregnancy-related symptoms and other chronic conditions has increased among pregnant women, favored by decriminalization and/or legalization of its recreational uses in addition to its easy accessibility. However, there is evidence that prenatal Cannabis exposure might have adverse consequences on pregnancy progression and a deleterious impact on proper neurodevelopmental trajectories in the offspring. Maternal Cannabis use could interfere with the complex and finely controlled role performed by the endocannabinoid system in reproductive physiology, impairing multiple gestational processes from blastocyst implantation to parturition, with long-lasting intergenerational effects. In this review, we discuss current clinical and preclinical evidence regarding the role of endocannabinoids in development, function, and immunity of the maternal–fetal interface, focusing on the impact of Cannabis constituents on each of these gestational processes. We also discuss the intrinsic limitations of the available studies and the future perspectives in this challenging research field.

Elevated human placental heat shock protein 5 is associated with spontaneous preterm birth

BACKGROUND

Specific heat shock proteins are associated with pregnancy complications, including spontaneous preterm birth (SPTB). Placental proteomics and whole exome sequencing recently suggested an association between heat shock protein HSPA5 and uncomplicated SPTB. In the present study, we investigated the localization of and possible roles for HSPA5 in SPTB.

METHODS

Western blot was performed to validate the result from the previously published proteomic analysis. We used qPCR to assess mRNA expression of genes and immunohistochemistry and immunoelectron microscopy to examine localization of HSPA5 in placental tissue. We silenced the HSPA5 gene in the HTR8/SVneo human trophoblast cell line to investigate possible functions of HSPA5.

RESULTS

HSPA5 was upregulated in placentas from SPTBs compared to spontaneous term births. We did not observe upregulation of HSPA5 mRNA in placental samples. The protein was localized in placental trophoblast in both spontaneous preterm and term placentas. Gene silencing of HSPA5 in human trophoblast cell culture affected the inflammatory response and decreased the expression of several proinflammatory genes.

CONCLUSIONS

We suggest that upregulation of HSPA5 in the placenta is associated with spontaneous preterm labor. HSPA5 may promote the inflammatory response and alter the anti-inflammatory state of the placenta which could eventually lead to premature labor.

IMPACT

We validated upregulation of HSPA5 in placentas from spontaneous preterm birth. HSPA5 was not upregulated at transcriptional level which suggests that it may be regulated post-translationally. Silencing HSPA5 in a human trophoblast-derived cell line suggested that HSPA5 promotes expression of proinflammatory cytokines. The emerging inflammation could lead to spontaneous preterm labor. Identifying inflammatory pathways and factors associated with spontaneous preterm birth increases knowledge of the molecular mechanisms of premature labor. This could provide cues to predict imminent premature labor and lead to information about how to safely maintain pregnancies.

Methyltransferase-like 3 aggravates endoplasmic reticulum stress in preeclampsia by targeting TMBIM6 in YTHDF2-dependent manner

BACKGROUND

With the increasing morbidity and mortality of preeclampsia (PE), it has posed a huge challenge to public health. Previous studies have reported endoplasmic reticulum (ER) stress could contribute to trophoblastic dysfunction which was associated with the N⁶-methyladenosine (m⁶A) modification by methyltransferase-like 3 (METTL3), resulting in PE. However, little was known about the relationship between METTL3 and ER stress in PE. Thus, in vitro and in vivo studies were performed to clarify the mechanism about how METTL3 affects the trophoblasts under ER stress in PE and to explore a therapeutic approach for PE.

METHODS

An ER stress model in HTR-8/SVneo cells and a preeclamptic rat model were used to study the mechanism and explore a therapeutic approach for PE. Western blot, immunohistochemistry, quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and methylated RNA immunoprecipitation (MeRIP)-qPCR were performed to detect the protein, RNA, and methylated transmembrane BAX inhibitor motif containing 6 (TMBIM6) expression levels. The m⁶A colorimetric and mRNA stability assays were used to measure the m⁶A levels and TMBIM6 stability, respectively. Short hairpin RNAs (shRNAs) were used to knockdown METTL3 and YTH N6-methyladenosine RNA binding protein 2 (YTHDF2). Flow cytometry and Transwell assays were performed to evaluate the apoptosis and invasion abilities of trophoblasts.

RESULTS

Upregulated METTL3 and m⁶A levels and downregulated TMBIM6 levels were observed in preeclamptic placentas under ER stress. The ER stress model was successfully constructed, and knockdown of METTL3 had a beneficial effect on HTR-8/SVneo cells under ER stress as it decreased the levels of methylated TMBIM6 mRNA. Moreover, overexpression of TMBIM6 was beneficial to HTR-8/SVneo cells under ER stress as it could neutralize the harmful effects of METTL3 overexpression. Similar to the knockdown of METTL3, downregulation of YTHDF2 expression resulted in the increased expression and mRNA stability of TMBIM6. Finally, improved systemic symptoms as well as protected placentas and fetuses were demonstrated in vivo.

CONCLUSIONS

METTL3/YTHDF2/TMBIM6 axis exerts a significant role in trophoblast dysfunction resulting in PE while inhibiting METTL3 may provide a novel therapeutic approach for PE.

Evidence of Increased Oxidative Stress in the Placental Tissue of Women Who Suffered an Episode of Psychosis during Pregnancy

Psychosis is a complex clinical syndrome resulting in a loss of contact with reality and alterations in behavior and sensorial and motor functions. Although the onset of psychosis can be related to any medical condition, most cases of psychosis are not fully understood. Psychosis may manifest for the first time during pregnancy, which is detrimental to maternofetal well-being. The impact of having a first episode of psychosis during pregnancy on the placenta has not yet been explored. Oxidative stress is thought to take part in the etiopathogenesis of this complex disorder, and this condition can also affect the placenta as it is highly sensitive to changes in the maternal environment. In this sense, the aim of the present work was to study the gene and protein expression through RT-qPCR and immunohistochemistry, respectively, of oxidative stress markers (NOX-1, NOX-2, iNOS, eNOS and PARP) in the placental tissue of women who underwent a first episode of psychosis during pregnancy (FE-PW) in comparison to healthy pregnant women. Our results showed augmented gene and protein expression of NOX-1, NOX-2, iNOS and PARP in the placental tissue of FE-PW. For the first time, we demonstrated that oxidative stress may have an important pathophysiological role in this tissue, aiding in explaining the impact of psychosis on pregnancy and the need for future studies in this field to guide better clinical management of these patients.

Mechanism and Role of Endoplasmic Reticulum Stress in Osteosarcoma

Osteosarcoma is the most common malignant bone tumor, often occurring in children and adolescents. The etiology of most patients is unclear, and the current conventional treatment methods are chemotherapy, radiotherapy, and surgical resection. However, the sensitivity of osteosarcoma to radiotherapy and chemotherapy is low, and the prognosis is poor. The development of new and useful treatment strategies for improving patient survival is an urgent need. It has been found that endoplasmic reticulum (ER) stress (ERS) affects tumor angiogenesis, invasion, etc. By summarizing the literature related to osteosarcoma and ERS, we found that the unfolded protein response (UPR) pathway activated by ERS has a regulatory role in osteosarcoma proliferation, apoptosis, and chemoresistance. In osteosarcoma, the UPR pathway plays an important role by crosstalk with autophagy, oxidative stress, and other pathways. Overall, this article focuses on the relationship between ERS and osteosarcoma and reviews the potential of drugs or gene targets associated with ERS for the treatment of osteosarcoma.

LncRNA LINC00534 regulates cell proliferation and migration via the miR-494-3p/PTEN axis in HTR-8/SVneo cells

BACKGROUND

LncRNA LINC00534 has been found to be differentially expressed in placental tissue samples of preeclampsia (PE), but the exact mechanism is still unclear.

METHODS

In vitro assays were carried out in HTR-8/SVneo cells using various methods, including cell counting kit-8 (CCK-8), transwells, flow cytometry, and Western blotting (WB) and quantitative polymerase chain reaction. RNA pull-down and bioinformatics analysis were applied to examine other potential underlying mechanisms involved.

RESULTS

We found that there was a high expression of LINC00534 in the placental tissues of patients with PE. LINC00534 overexpression (OE) significantly inhibited cell proliferation and migration as well as accelerated cell apoptosis in HTR8/SVneo cells. The knockdown of LINC00534 produced an opposite trend. Mechanistically, LINC00534 promoted the expressions of PTEN (Phosphatase and tensin homolog) through decreasing miR-494-3p. Further rescue studies showed that LINC00534 played a role by targeting mir-494-3p, which controlled the growth and migration of HTR-8/SVneo trophoblast cells via regulating PTEN/PI3K/AKT (Phosphatidylinositol3-kinase/protein kinase B). Moreover, lncRNA pull-down assay identified 198 potential bound proteins for LINC00534. Those proteins were mostly involved in RNA processing and modification, posttranslational modification, protein turnover, and chaperones.

CONCLUSION

Overall, by suppressing HTR8/SVneo cell growth and migration via the miR-494-3p/PTEN axis and other mechanisms, LINC00534 offers new insight into PE pathogenesis.

Inhibition of the AT1R agonistic autoantibody in a rat model of preeclampsia improves fetal growth in late gestation

Placenta ischemia, the initiating event in preeclampsia (PE), is associated with fetal growth restriction. Inhibition of the agonistic autoantibody against the angiotensin type 1 receptor AT1-AA, using an epitope-binding inhibitory peptide ('n7AAc') attenuates increased blood pressure at gestational day (G)19 in the clinically relevant reduced uterine perfusion pressure (RUPP) model of PE. Thus we tested the hypothesis that maternal administration of 'n7AAc' does not transfer to the fetus, improves uterine blood flow and fetal growth, and attenuates elevated placental expression of miRNAs implicated in PE and FGR. Sham or RUPP surgery was performed at G14 with vehicle or 'n7AAc' (144 µg/day) administered via an osmotic pump from G14 to G20. Maternal plasma levels of the peptide on G20 were 16.28 ± 4.4 nM, and fetal plasma levels were significantly lower at 1.15 ± 1.7 nM (P = 0.0007). The uterine artery resistance index was significantly elevated in RUPP (P < 0.0001) but was not increased in 'n7AAc'-RUPP or 'n7AAc'-Sham versus Sham. A significant reduction in fetal weight at G20 in RUPP (P = 0.003) was not observed in 'n7AAc'-RUPP. Yet, percent survival was reduced in RUPP (P = 0.0007) and 'n7AAc'-RUPP (P < 0.0002). Correlation analysis indicated the reduction in percent survival during gestation was specific to the RUPP (r = 0.5342, P = 0.043) and independent of 'n7AAc'. Placental miR-155 (P = 0.0091) and miR-181a (P = 0.0384) expression was upregulated in RUPP at G20 but was not elevated in 'n7AAc'-RUPP. Collectively, our results suggest that maternal administration of 'n7AAc' does not alter fetal growth in the RUPP implicating its potential as a therapeutic for the treatment of PE.NEW & NOTEWORTHY The seven amino acid inhibitory peptide to the AT1-AA ('n7AAc') has limited transfer to the fetus at gestational day 20, improves uterine blood flow and fetal growth in the reduced uterine perfusion pressure model of preeclampsia (PE), and does not impair fetal survival during gestation in sham-operated or placental ischemic rats. Collectively, these findings suggest that maternal administration of 'n7AAc' as an effective strategy for the treatment of PE is associated with improved outcomes in the fetus.

Downregulation of LINC00221 promotes angiopoiesis in HUVEC and inhibits recruitment of macrophages by augmenting miR-542-3p in trophoblast cells

PURPOSE

To investigate the effects of long intergenic non-protein coding RNA 221 (LINC00221) on preeclampsia (PE) and its mechanism.

METHODS

The expression of LINC00221 was detected in placental tissues from PE patients and normal pregnant women (non-PE). Next, the effects of LINC00221 silencing on trophoblast cells (HTR-8/SVneo and JEG-3) and co-cultured HUVECs or macrophages were evaluated. Afterwards, miR-542-3p was confirmed to bind to LINC00221 directly, and miR-542-3p mimics and inhibitors were transfected into trophoblast cells. Next, a rescue experiment was performed to examine the effect of LINC00221/miR-542-3p axis. Finally, the effect of LINC00221 was also verified in vivo in rat PE models.

RESULTS

The expression of LINC00221 was higher in placental tissues of PE patients than those of non-PE. LINC00221 silencing significantly reduced MCP1 level and increased the VEGF level in trophoblast cells. LINC00221 knockdown in trophoblast cells remarkably enhanced VEGFR expression and the angiopoiesis of HUVECs, and decreased the migration and invasion of macrophages and reduced TNF-α level. Besides, LINC00221 knockdown decreased CHOP, p-IREα, p-PERK, and iNOS expression and increased Trx expression. Notably, LINC00221 negatively regulated miR-542-3p expression. MiR-542-3p overexpression had an effect to that of LINC00221 knockdown, while miR-542-3p inhibition had the opposite effect. Treatment with miR-542-3p inhibitors partially reversed the protective effect of LINC00221 silencing. PE rat model results were consistent with those of in vitro experiments.

CONCLUSIONS

Downregulation of LINC00221 might reduce dysfunction, inflammatory responses, endoplasmic reticulum stress, and oxidative stress, and thereby protect against PE by augmenting miR-542-3p.

Maternal hypothyroidism causes oxidative stress and endoplasmic reticulum stress in the maternal-fetal interface of rats

Maternal hypothyroidism is associated with pre-eclampsia and intrauterine growth restriction, gestational diseases involving oxidative stress (OS) and endoplasmic reticulum stress (ERS) in the placenta. However, it is not known whether hypothyroidism also causes OS and ERS at the maternal-fetal interface. The aim was to evaluate the fetal-placental development and the expression of mediators of OS and of the unfolded protein response (UPR) in the maternal-fetal interface of hypothyroid rats. Hypothyroidism was induced in Wistar rats with propylthiouracil and the fetal-placental development and placental and decidual expression of antioxidant, hypoxia, and UPR mediators were analyzed at 14 and 18 days of gestation (DG), as well the expression of 8-OHdG and MDA, and reactive oxygen species (ROS) and peroxynitrite levels. Hypothyroidism reduced fetal weight at 14 and 18 DG, in addition to increasing the percentage of fetal death and reducing the weight of the uteroplacental unit at 18 DG. At 14 DG, there was greater decidual and/or placental immunostaining of Hif1α, 8-OHdG, MDA, SOD1, GPx1/2, Grp78 and CHOP in hypothyroid rats, while there was a reduction in placental and/or decidual gene expression of Sod1, Gpx1, Atf6, Perk, Ho1, Xbp1, Grp78 and Chop in the same gestational period. At 18 DG, hypothyroidism increased the placental ROS levels and the decidual and/or placental immunostaining of HIF1α, 8-OHdG, MDA, ATF4, GRP78 and CHOP, while it reduced the immunostaining and enzymatic activity of SOD1, CAT, GST. Hypothyroidism increased the placental mRNA expression of Hifα, Nrf2, Sod2, Gpx1, Cat, Perk, Atf6 and Chop at 18 DG, while decreasing the decidual expression of Sod2, Cat and Atf6. These findings demonstrated that fetal-placental restriction in female rats with hypothyroidism is associated with hypoxia and dysregulation in placental and decidual expression of UPR mediators and antioxidant enzymes, and activation of oxidative stress and endoplasmic reticulum stress at the maternal-fetal interface.

Maternal obesity: new placental paradigms unfolded

The prevalence of maternal obesity is increasing at an alarming rate, and is providing a major challenge for obstetric practice. Adverse effects on maternal and fetal health are mediated by complex interactions between metabolic, inflammatory, and oxidative stress signaling in the placenta. Endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) are common downstream pathways of cell stress, and there is evidence that this conserved homeostatic response may be a key mediator in the pathogenesis of placental dysfunction. We summarize the current literature on the placental cellular and molecular changes that occur in obese women. A special focus is cast onto placental ER stress in obese pregnancy, which may provide a novel link for future investigation.

Increased NOS coupling by the metabolite tetrahydrobiopterin (BH4) reduces preeclampsia/IUGR consequences

Preeclampsia (PE) is a high-prevalence pregnancy disease characterized by placental insufficiency, gestational hypertension, and proteinuria. Overexpression of the A isoform of the STOX1 transcription factor (STOX1A) recapitulates PE in mice, and STOX1A overexpressing trophoblasts recapitulate PE patients hallmarks in terms of gene expression and pathophysiology. STOX1 overexpression induces nitroso-redox imbalance and mitochondrial hyper-activation. Here, by a thorough analysis on cell models, we show that STOX1 overexpression in trophoblasts alters inducible nitric oxide synthase (iNOS), nitric oxide (NO) content, the nitroso-redox balance, the antioxidant defense, and mitochondrial function. This is accompanied by specific alterations of the Krebs cycle leading to reduced l-malate content. By increasing NOS coupling using the metabolite tetrahydrobiopterin (BH4) we restore this multi-step pathway in vitro. Moving in vivo on two different rodent models (STOX1 mice and RUPP rats, alike early onset and late onset preeclampsia, respectively), we show by transcriptomics that BH4 directly reverts STOX1-deregulated gene expression including glutathione metabolism, oxidative phosphorylation, cholesterol metabolism, inflammation, lipoprotein metabolism and platelet activation, successfully treating placental hypotrophy, gestational hypertension, proteinuria and heart hypertrophy. In the RUPP rats we show that the major fetal issue of preeclampsia, Intra Uterine Growth Restriction (IUGR), is efficiently corrected. Our work posits on solid bases BH4 as a novel potential therapy for preeclampsia.

The genetic risk factors for pregnancy-induced hypertension: Evidence from genetic polymorphisms

Pregnancy-induced hypertension (PIH) is a multifactorial and severe pregnancy complication including preeclampsia/eclampsia, gestational hypertension, chronic (pre-existing) hypertension, and preeclampsia/eclampsia variants superimposed on chronic hypertension. PIH-induced maternal mortality accounts for approximately 9% of all maternal deaths over the world. A large number of case-control studies have established the importance of various genetic factors in the occurrence and development of PIH. In this narrative review, we summarized the genetic risk factors involved in the renin-angiotensin system, endothelin system, inflammatory factors, oxidative stress, and other functional networks, with the aim of sorting out the genetic factors that may play a potential role in PIH and providing new ideas to elucidate the pathogenesis of PIH.

Primary Human Trophoblasts Mimic the Preeclampsia Phenotype after Acute Hypoxia-Reoxygenation Insult

Preeclampsia (PE) is a pregnancy-specific disorder that affects 3 to 5% of pregnancies worldwide and is one of the leading causes of maternal and fetal morbidity and mortality. Nevertheless, how these events occur remains unclear. We hypothesized that the induction of hypoxic conditions in vitro in primary human trophoblast cells would mimic several characteristics of PE found in vivo. We applied and characterized a model of primary cytotrophoblasts isolated from healthy pregnancies that were placed under different oxygen concentrations: ambient O₂ (5% pCO₂, 21%pO₂, 24 h, termed “normoxia”), low O₂ concentration (5% pCO₂, 1.5% pO₂, 24 h, termed “hypoxia”), or “hypoxia/reoxygenation” (H/R: 6 h intervals of normoxia and hypoxia for 24 h). Various established preeclamptic markers were assessed in this cell model and compared to placental tissues obtained from PE pregnancies. Seventeen PE markers were analyzed by qPCR, and the protein secretion of soluble fms-like tyrosine kinase 1 (sFlT-1) and the placenta growth factor (PlGF) was determined by ELISA. Thirteen of seventeen genes associated with angiogenesis, the renin–angiotensin system, oxidative stress, endoplasmic reticulum stress, and the inflammasome complex were susceptible to H/R and hypoxia, mimicking the expression pattern of PE tissue. In cell culture supernatants, the secretion of sFlT-1 was increased in hypoxia, while PlGF release was significantly reduced in H/R and hypoxia. In the supernatants of our cell models, the sFlT-1/PlGF ratio in hypoxia and H/R was higher than 38, which is a strong indicator for PE in clinical practice. These results suggest that our cellular models reflect important pathological processes occurring in PE and are therefore suitable as PE in vitro models.

Pathological Role of Reactive Oxygen Species on Female Reproduction

Oxidative stress (OS), a clinical predicament characterized by a shift in homeostatic imbalance among prooxidant molecules embracing reactive oxygen species (ROS) and reactive nitrogen species (RNS), along with antioxidant defenses, has been established to play an indispensable part in the pathophysiology of subfertility in both human males and females. ROS are highly reactive oxidizing by-products generated during critical oxygen-consuming processes or aerobic metabolism. A healthy body system has its own course of action to maintain the equilibrium between prooxidants and antioxidants with an efficient defense system to fight against ROS. But when ROS production crosses its threshold, the disturbance in homeostatic balance results in OS. Besides their noxious effects, literature studies have depicted that controlled and adequate ROS concentrations exert physiologic functions, especially that gynecologic OS is an important mediator of conception in females. Yet the impact of ROS on oocytes and reproductive functions still needs a strong attestation for further analysis because the disruption in prooxidant and antioxidant balance leads to abrupt ROS generation initiating multiple reproductive diseases such as polycystic ovary syndrome (PCOS), endometriosis, and unexplained infertility in addition to other impediments in pregnancy such as recurrent pregnancy loss, spontaneous abortion, and preeclampsia. The current article elucidates the skeptical state of affairs created by ROS that influences female fertility.

PPARγ-A Factor Linking Metabolically Unhealthy Obesity with Placental Pathologies

Obesity is a known factor in the development of preeclampsia. This paper links adipose tissue pathologies with aberrant placental development and the resulting preeclampsia. PPARγ, a transcription factor from the ligand-activated nuclear hormone receptor family, appears to be one common aspect of both pathologies. It is the master regulator of adipogenesis in humans. At the same time, its aberrantly low activity has been observed in placental pathologies. Overweight and obesity are very serious health problems worldwide. They have negative effects on the overall mortality rate. Very importantly, they are also conducive to diseases linked to impaired placental development, including preeclampsia. More and more people in Europe are suffering from overweight (35.2%) and obesity (16%) (EUROSTAT 2021 data), some of them young women planning pregnancy. As a result, we will be increasingly encountering obese pregnant women with a considerable risk of placental development disorders, including preeclampsia. An appreciation of the mechanisms shared by these two conditions may assist in their prevention and treatment. Clearly, it should not be forgotten that health education concerning the need for a proper diet and physical activity is of utmost importance here.

Isoginkgetin attenuates endoplasmic reticulum stress-induced autophagy of brain after ischemic reperfusion injury

Isoginkgetin is characterized by properties of potent anticancer and anti-inflammation. To explore its effect on ischemic stroke, a rat model of ischemia/reperfusion (I/R) injury was established and induced by transient middle cerebral artery occlusion/reperfusion (MCAO/R). Different doses of isoginkgetin were intraperitoneally injected into each rat. Expressions of ER stress activation-related makers including phosphorylated inositol-requiring enzyme 1 (IRE1), phosphorylated protein kinase RNA-like endoplasmic reticulum kinase (p-PERK), activating transcription factor-6 (ATF6), and two autophagy markers (ratio of LC3II/I and Beclin-1) were detected by western blot. Infarct volume, neurological deficits, and brain water content were detected. The results showed that ER stress and autophagy were activated by cerebral (I/R) injury, which could be effectively attenuated following pre-ischemia isoginkgetin administration. Moreover, autophagy induced by ER stress was triggered by the activation of PERK and IRE1 pathways. ER stress inhibitor (4-PBA) and ER related signaling inhibitors including PERK, GSK, IRE1, and DBSA markedly inhibited ER stress and autophagy induced by I/R. In addition, isoginkgetin markedly mitigated cerebral infarction, edema, neuronal apoptosis as well as neurological impairment induced by I/R injury, while tunicamycin (ER stress activator TM) and rapamycin (autophagy activator RAPA) could eliminate these lesions. This research identified a novel therapeutic agent isoginkgetin, which could effectively attenuate I/R injury by blocking autophagy induced by ER stress.

The Placenta's Role in Sexually Dimorphic Fetal Growth Strategies

Fetal sex affects the risk of pregnancy complications and the long-term effects of prenatal environment on health. Some have hypothesized that growth strategies differ between the sexes, whereby males prioritize growth whereas females are more responsive to their environment. This review evaluates the role of the placenta in such strategies, focusing on (1) mechanisms underlying sexual dimorphism in gene expression, (2) the nature and extent of sexual dimorphism in placental gene expression, (3) sexually dimorphic responses to nutrient supply, and (4) sexual dimorphism in morphology and histopathology. The sex chromosomes contribute to sex differences in placental gene expression, and fetal hormones may play a role later in development. Sexually dimorphic placental gene expression may contribute to differences in the prevalence of complications such as preeclampsia, although this link is not clear. Placental responses to nutrient supply frequently show sexual dimorphism, but there is no consistent pattern where one sex is more responsive. There are sex differences in the prevalence of placental histopathologies, and placental changes in pregnancy complications, but also many similarities. Overall, no clear patterns support the hypothesis that females are more responsive to the maternal environment, or that males prioritize growth. While male fetuses are at greater risk of a variety of complications, total prenatal mortality is higher in females, such that males exposed to early insults may be more likely to survive and be observed in studies of adverse outcomes. Going forward, robust statistical approaches to test for sex-dependent effects must be more widely adopted to reduce the incidence of spurious results.

Placental Ischemia Says "NO" to Proper NOS-Mediated Control of Vascular Tone and Blood Pressure in Preeclampsia

In this review, we first provide a brief overview of the nitric oxide synthase (NOS) isoforms and biochemistry. This is followed by describing what is known about NOS-mediated blood pressure control during normal pregnancy. Circulating nitric oxide (NO) bioavailability has been assessed by measuring its metabolites, nitrite (NO₂) and/or nitrate (NO₃), and shown to rise throughout normal pregnancy in humans and rats and decline postpartum. In contrast, placental malperfusion/ischemia leads to systemic reductions in NO bioavailability leading to maternal endothelial and vascular dysfunction with subsequent development of hypertension in PE. We end this article by describing emergent risk factors for placental malperfusion and ischemic disease and discussing strategies to target the NOS system therapeutically to increase NO bioavailability in preeclamptic patients. Throughout this discussion, we highlight the critical importance that experimental animal studies have played in our current understanding of NOS biology in normal pregnancy and their use in finding novel ways to preserve this signaling pathway to prevent the development, treat symptoms, or reduce the severity of PE.

The unfolded protein response and apoptotic regulation in the human placenta due to maternal cigarette smoking and pre-eclampsia

Maternal cigarette smoking (CS) and pre-eclampsia (PE) alter placental function and expression of important proteins which maintain homeostasis. Two interlinked pathways of interest are the unfolded protein response (UPR) and apoptosis. The UPR is upregulated in the PE placenta, but no data is available on the effects of CS and how it correlates with apoptotic expression. Samples of human placental tissue from normotensive non-smokers (n = 8), women with PE (n = 8), and CS (n = 8) were analysed using immunohistochemistry for 3 UPR markers (phosphorylated PKR-like endoplasmic reticulum (ER) kinase (pPERK), inositol-requiring enzyme 1 (IRE1), activating transcription factor 6 (ATF6)), and an antibody microarray for 19 apoptotic and stress regulating markers. For the PE group compared to the normotensive group, staining for pPERK was increased in decidual tissue and villi, and for IRE1, the overall percentage of stained villi per field of view was increased. There were no differences in UPR expression comparing CS to controls. Of the apoptotic markers, only IκBα (Ser32/36), which is part of an inhibitory pathway, showed a significant decrease in the PE and CS groups compared to controls. These findings suggest UPR regulation is more evident in PE with a general increase in ER stress due to decreased inhibition of apoptosis as compared to CS for which UPR was not altered.

Uteroplacental Circulation in Normal Pregnancy and Preeclampsia: Functional Adaptation and Maladaptation

Uteroplacental blood flow increases as pregnancy advances. Adequate supply of nutrients and oxygen carried by uteroplacental blood flow is essential for the well-being of the mother and growth/development of the fetus. The uteroplacental hemodynamic change is accomplished primarily through uterine vascular adaptation, involving hormonal regulation of myogenic tone, vasoreactivity, release of vasoactive factors and others, in addition to the remodeling of spiral arteries. In preeclampsia, hormonal and angiogenic imbalance, proinflammatory cytokines and autoantibodies cause dysfunction of both endothelium and vascular smooth muscle cells of the uteroplacental vasculature. Consequently, the vascular dysfunction leads to increased vascular resistance and reduced blood flow in the uteroplacental circulation. In this article, the (mal)adaptation of uteroplacental vascular function in normal pregnancy and preeclampsia and underlying mechanisms are reviewed.

Association of endothelial nitric oxide synthase gene variants with preeclampsia

Background

Preeclampsia (PE) is a complex pregnancy hypertensive disorder with multifaceted etiology. The endothelial nitric oxide synthase (eNOS) gene and nitric oxide (NO) levels has been reported to be associated with PE predisposition in various populations. Therefore, present study was designed to investigate the role of NO levels and eNOS gene variants in preeclamptic women in Pakistan.

Methods

A total of 600 women were evaluated, 188 of PE with mild features, 112 of PE with severe features and 300 normotensive pregnant women. NO levels were detected by Greiss reaction method and genotyping following sequencing was conducted for eNOS gene variants. Further insilico studies were performed to get insights into the structural and functional impact of identifies mutation on eNOS protein as well as on protein regulation.

Results

Reduced concentrations of NO were reported in all PE groups (p < 0.05) as compared to controls. The frequency of c.894 T (p.298Asp) and g.-786C alleles were significantly associated with PE. In addition, novel homozygous variant g.2051G > A was also significantly associated with PE when compared to normotensive women. Dynamic simulation studies revealed that Glu298Asp mutation destabilize the protein molecule and decrease the overall stability of eNOS protein. Molecular docking analysis of mutant promoter with transcription factors STAT3 and STAT6 proposed changes in protein regulation upon these reported mutations in upstream region of the gene.

Conclusion

Considering the results of current study, the functional alterations induced by these variants may influence the bioavailability of NO and represents a genetic risk factor for increased susceptibility to PE. However, large studies or meta-analysis are necessary to validate these findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12978-021-01213-9.

Preeclampsia (PE) is a complex pregnancy hypertensive disorder with multifaceted etiology characterized by increased hypertension and proteinuria after 20 weeks of gestation. The present study was directed to determine the role of eNOS in susceptibility to PE and the association of c.894G > T (p.(Glu298Asp), intron 4b/4a, g.-786 T > C and other possible variants of eNOS gene with preeclampsia in Pakistani population. Computational analysis of identified variants in the coding and non-coding region of the eNOS gene was also conducted to determine the change in gene regulation and further protein stability. A total of 600 women were evaluated, 188 with mild and 112 with PE with severe features PE with 300 normotensive pregnant women. NO levels and genotyping following sequencing was conducted for eNOS gene variants. Further insilico studies were performed to get insights into the structural and functional impact of identifies mutation on eNOS protein as well as on protein regulation. Data from the current study suggest that there might be other risk variants of the eNOS gene (g.2051G > A and g.1861G > A) and lower levels of serum NO that confers in an increased risk of PE. The detailed computational investigation further confirmed the deformities and changes in protein flexibility upon Glu298Asp. These structural alterations might be associated with preeclampsia. Variants in the promoter region of the eNOS gene further validate the change in gene regulation for the onset of disease. Identification of key structural and functional features in eNOS protein and gene regulatory region might be used for designing specific drugs for therapeutic purpose.

Newborns of Mothers with Venous Disease during Pregnancy Show Increased Levels of Lipid Peroxidation and Markers of Oxidative Stress and Hypoxia in the Umbilical Cord

Chronic venous disease (CVD) encompasses a set of disorders of the venous system that have a high prevalence in Western societies and are associated with significant sociohealth costs. Pregnancy is a period in which different hormonal and haemodynamic changes occur that lead to significant changes in the cardiovascular system, increasing the risk of developing venous problems, especially during the third trimester of gestation. In turn, CVD involves a series of local and systemic alterations that can have negative repercussions in pregnancy. In this context, the role of oxidative stress in the pathophysiology of this condition has been shown to significantly affect other vascular structures during pregnancy, such as the placenta. However, the effects of oxidative stress on the umbilical cord in women with CVD have not yet been fully elucidated. Thus, the objective of this study was to analyse the gene and protein expression of the enzymes NOX-1, NOX-2 and iNOS, which are involved in the production of reactive oxygen and nitrogen species, respectively. Similarly, the presence of hypoxia-inducible factor 1-alpha (HIF-1α) in the umbilical cord in women with CVD was compared to that of pregnant control women, and the levels of the lipid peroxidation marker malonyldialdehyde (MDA) in cord tissue and blood was also analysed. Our results support a significant increase in the enzymes NOX-1, NOX-2 and iNOS and HIF-1α and MDA in the umbilical cord tissue and blood of women with CVD. For the first time, our work demonstrates an increase in oxidative stress and cellular damage in the umbilical cords of pregnant women who develop this condition, deepening the understanding of the consequences of CVD during pregnancy.

Syncytiotrophoblast stress in early onset preeclampsia: The issues perpetuating the syndrome

Preeclampsia is a pregnancy-specific syndrome characterized by a sudden increase in blood pressure accompanied by proteinuria and/or maternal multi-system damage associated to poor fetal outcome. In early-onset preeclampsia, utero-placental perfusion is altered, causing constant and progressive damage to the syncytiotrophoblast, generating syncytiotrophoblast stress. The latter leads to the detachment and release of syncytiotrophoblast fragments, anti-angiogenic factors and pro-inflammatory molecules into maternal circulation, resulting in the emergence and persistence of the characteristic symptoms of this syndrome during pregnancy. Therefore, understanding the origin and consequences of syncytiotrophoblast stress in preeclampsia is vital to develop new therapeutic alternatives, focused on reducing the burden of this syndrome. In this review, we describe five central characteristics of syncytial stress that should be targeted or prevented in order to reduce preeclampsia symptoms: histological alterations, syncytiotrophoblast damage, antiangiogenic protein export, placental deportation, and altered syncytiotrophoblast turnover. Therapeutic management of these characteristics may improve maternal and fetal outcomes.

No evidence of the unfolded protein response in the placenta of two rodent models of preeclampsia and intrauterine growth restriction

In humans, intrauterine growth restriction (IUGR) and preeclampsia (PE) are associated with induction of the unfolded protein response (UPR) and increased placental endoplasmic reticulum (ER) stress. Especially in PE, oxidative stress occurs relative to the severity of maternal vascular underperfusion (MVU) of the placental bed. On the premise that understanding the mechanisms of placental dysfunction could lead to targeted therapeutic options for human IUGR and PE, we investigated the roles of the placental UPR and oxidative stress in two rodent models of these human gestational pathologies. We employed a rat IUGR model of gestational maternal protein restriction, as well as an endothelial nitric oxide synthase knockout mouse model (eNOS-/-) of PE/IUGR. Placental expression of UPR members was analyzed via qRT-PCR (Grp78, Calnexin, Perk, Chop, Atf6, and Ern1), immunohistochemistry, and Western blotting (Calnexin, ATF6, GRP78, CHOP, phospho-eIF2α, and phospho-IRE1). Oxidative stress was determined via Western blotting (3-nitrotyrosine and 4-hydroxy-2-nonenal). Both animal models showed a significant reduction of fetal and placental weight. These effects did not induce placental UPR. In contrast to human data, results from our rodent models suggest retention of placental plasticity in the setting of ER stress under an adverse gestational environment. Oxidative stress was significantly increased only in female IUGR rat placentas, suggesting a sexually dimorphic response to maternal malnutrition. Our study advances understanding of the involvement of the placental UPR in IUGR and PE. Moreover, it emphasizes the appropriate choice of animal models researching various aspects of these pregnancy complications.

Transcriptional profiling of the response to the trichloroethylene metabolite S-(1,2-dichlorovinyl)-L-cysteine revealed activation of the eIF2α/ATF4 integrated stress response in two in vitro placental models

Trichloroethylene (TCE) is an industrial solvent and widespread environmental contaminant. Although TCE exposure is prevalent, epidemiological studies of TCE exposure associations with adverse birth outcomes are inconclusive. Prior studies show that the TCE metabolite S-(1,2-dichlorovinyl)-L-cysteine (DCVC) exhibits toxicity in a placental cell line. In the current study, genome-wide gene expression and gene set enrichment analyses were used to identify novel genes and pathway alterations in the HTR-8/SVneo human trophoblast cell line and human placental villous explants treated with DCVC at concentrations relevant to human exposures. In the cells, concentration- and time-dependent effects were observed, as evidenced by the magnitude of altered gene expression after treatment with 20 µM DCVC versus 10 µM, and 12-h versus 6-h of treatment. Comparing the two models for the transcriptional response to 12-h 20 µM DCVC treatment, no differentially expressed genes reached significance in villous explants, whereas 301 differentially expressed genes were detected in HTR-8/SVneo cells compared with non-treated controls (FDR < 0.05 + LogFC > 0.35 [FC > 1.3]). GSEA revealed five upregulated enriched pathways in common between explants and cells (FDR < 0.05). Moreover, all 12-h DCVC treatment groups from both models contained upregulated pathways enriched for genes regulated by the ATF4 transcription factor. The overrepresentation of ATF4 regulation of differentially expressed genes indicated activation of the integrated stress response (ISR), a condition triggered by multiple stress stimuli, including the unfolded protein response. DCVC-induced ISR activation was confirmed by elevated eIF2α phosphorylation, ATF4 protein concentrations, and decreased global protein synthesis in HTR-8/SVneo cells. This study identifies a mechanism of DCVC-induced cytotoxicity by revealing the involvement of a specific stress signaling pathway.

The value of prenatal magnetic resonance imaging and postnatal follow-up using Gesell Developmental Schedules score for mild-to-moderate simple bilateral fetal ventriculomegaly

OBJECTIVE

To investigate the relationship of mild-to-moderate simple bilateral fetal ventriculomegaly with postnatal neurological development.

METHODS

Cases of simple lateral ventricular dilatation (273) were divided into bilateral mild dilatation (10.0-12.0 mm, 62), bilateral moderate dilatation (12.1-15.0 mm, 29), unilateral mild dilatation (133), and unilateral moderate dilatation (49) groups. The control group comprised 50 normal fetuses. Neurological development was assessed using Gesell Developmental Schedules (GDS) at postnatal 3, 6, 12, and 18 months.

RESULTS

At postnatal 6, 12, and 18 months, the GDS score was higher for bilateral than for unilateral dilatation (p < .05). At postnatal 3 and 6 months, the GDS score was higher for the bilateral dilatation groups than for the control group (p < .05). At postnatal 6, 12, and 18 months, the GDS score was higher for the bilateral moderate dilatation group than for the unilateral moderate dilatation group (p < .05). Further, at postnatal 3, 6, 12, and 18 months, the GDS score was higher for the bilateral moderate dilatation group than for the control group (p < .05).

CONCLUSION

At postnatal month 6, the GDS evaluation results of the bilateral dilatation groups were significantly inferior compared to those of the unilateral dilatation group.

Dietary Arthrospira platensis improves systemic antioxidant potential and changes plasma lipids without affecting related hepatic metabolic pathways in post-weaned piglets

BACKGROUND

The ability of a high level of dietary Arthrospira platensis, individually or in combination with two exogenous carbohydrate-degrading enzymes (lysozyme and Rovabio®), to improve systemic antioxidant potential and hepatic lipid metabolism was tested in piglets. Forty male post-weaned piglets, sons of Large White × Landrace sows crossed with Pietrain boars, were allocated into 4 groups (n = 10) and fed during 28 days one of the following diets: 1) a control basal diet (cereal and soybean meal); 2) a basal diet with 10% of A. platensis (AP); 3) the AP diet supplemented with 0.005% of Rovabio® (AP + R); 4) the AP diet supplemented with 0.01% of lysozyme (AP + L).

RESULTS

Arthrospira platensis decreased BW gain of piglets, regardless the addition of feed enzymes. The majority of plasma metabolites were affected by diets. A. platensis increased total lipids, total cholesterol and LDL-cholesterol, without changing hepatic fatty acid content or modulating, in an expressive manner, the transcriptional profile of lipid sensitive mediators. The antioxidant potential in general, and total carotenoids in particular, were improved by the microalga, regardless lysozyme or Rovabio®.

CONCLUSIONS

Summing up, A. platensis, individually and combined with feed enzymes, impacts negatively on piglets' growth but improves the systemic antioxidant potential and changes plasma lipids with a minor modulation on related hepatic metabolic pathways.

Activation of angiotensin type 2 receptor attenuates testosterone-induced hypertension and uterine vascular resistance in pregnant rats†

Preeclampsia is a pregnancy-related hypertensive disorder with unclear mechanisms. While hypersensitivity to angiotensin II via vasoconstrictive angiotensin type-1 receptor (AT1R) is observed in preeclampsia, the importance of vasodilatory angiotensin type-2 receptor (AT2R) in the control of vascular dysfunction is less clear. We assessed whether AT1R, AT2R, and endothelial nitric oxide synthase (eNOS) expression are altered in placental vessels of preeclamptic women and tested if ex vivo incubation with AT2R agonist Compound 21 (C21; 1 μM) could restore AT1R, AT2R, and eNOS balance. Further, using a rat model of gestational hypertension induced by elevated testosterone, we examined whether C21 (1 μg/kg/day, oral) could preserve AT1R and AT2R balance and improve blood pressure, uterine artery blood flow, and vascular function. Western blots revealed that AT1R protein level was higher while AT2R and eNOS protein were reduced in preeclamptic placental vessels, and AT2R agonist C21 decreased AT1R and increased AT2R and eNOS protein levels in preeclamptic vessels. In testosterone dams, blood pressure was higher, and uterine artery blood flow was reduced, and C21 treatment reversed these levels similar to those in controls dams. C21 attenuated the exaggerated Ang II contraction and improved endothelium-dependent vasorelaxation in uterine arteries of testosterone dams. These C21-mediated vascular effects were associated with decreased AT1R and increased AT2R and eNOS protein levels. C21 also increased serum nitrate/nitrite and bradykinin production in testosterone dams and attenuated the fetoplacental growth restriction. Thus, AT1R upregulation and AT2R downregulation are observed in preeclampsia and testosterone model, and increasing AT2R activity could help restore AT1R and AT2R balance and improve gestational vascular function.

Red blood cells from patients with pre-eclampsia induce endothelial dysfunction

RATIONALE

Pre-eclampsia is a multisystem disorder associated with systemic vascular dysfunction and decreased nitric oxide (NO) bioactivity. Arginase competes with NO synthase (NOS) for l-arginine, and its upregulation may reduce NOS-derived NO formation or induce production of reactive oxygen species (ROS) via uncoupling of NOS, resulting in endothelial dysfunction. Red blood cells (RBCs) have emerged as key players in NO homeostasis via their interactions with the endothelium. Studies have demonstrated that abnormal RBC arginase function in patients with diabetes contributes to oxidative stress and endothelial dysfunction.

AIM

The aim of the study was to investigate if reduced NO bioavailability and increased ROS in pre-eclampsia is mediated via RBC-dependent mechanisms.

METHODS

In this translational study, plasma and RBCs were isolated from gestationally matched pre-eclamptic and healthy pregnant women and co-incubated overnight with mouse aortas for vascular reactivity studies. NO bioactivity, that is, nitrate, nitrite and cGMP, was assessed in plasma. Arginase activity and expression were analysed in RBCs.

RESULTS

Plasma markers of NO homeostasis and signalling were decreased in pre-eclamptic women vs. healthy pregnant women. Co-incubation of aorta with pre-eclamptic RBCs, but not healthy pregnant RBCs, induced endothelial dysfunction, which was ameliorated by pharmacological inhibition of arginase, scavenging of ROS, and by nitrite treatment. This pathological vascular phenotype was not observed following incubation with pre-eclamptic plasma. Arginase expression and activity in RBCs were increased in pre-eclamptic vs. healthy pregnant women and was associated with pre-eclampsia severity. Pre-eclamptic RBC-induced endothelial dysfunction was not because of increased haemolysis/cell-free haemoglobin.

CONCLUSION

This study demonstrates a novel role of the RBC in mediating the endothelial dysfunction associated with pre-eclampsia through arginase-dependent and oxidative stress-dependent mechanisms. Targeting of RBC arginase may provide a novel treatment modality for pre-eclampsia.

Vasomotor tone-associated factors and pregnancy outcomes of women who undergo in vitro fertilization

Vasomotor tone-associated factors play important roles in normal pregnancy, but their roles in the pregnancy outcome of women who undergo in vitro fertilization and embryo transfer (IVF-ET) remain unclear. A total of 82 infertile women who underwent successful IVF-ET were enrolled, including 18 pregnancy losses, 11 complications, and 53 normal deliveries. The serum NO and iNOS levels were significantly higher in the pregnancy loss group and significantly lower in the complication group than in the normal delivery group (p < 0.05). Significantly increased ET-1 and decreased PGI2 were found in both the pregnancy loss and complication groups compared with those in the normal delivery group (p < 0.05). NO, iNOS, and ET-1 are risk factors and PGI2 is a protective factor for pregnancy loss. ET-1 + PGI2 (AUC, 0.897; sensitivity, 90.6%; specificity, 83.3%) showed a relatively good predictive value for pregnancy loss following IVF-ET.

Effect of nicotine on placental inflammation and apoptosis in preeclampsia-like model

AIMS

Placental tissues from patients with preeclampsia (PE) and in the lipopolysaccharide (LPS)-induced PE-like model were used to investigate the implication of placental inflammation and apoptosis in PE. Whether the beneficial effects of nicotine are related to inhibition of placental inflammation and apoptosis in the PE-like model were investigated.

MAIN METHODS

Placental apoptosis was detected in PE patients and the PE-like rat model by TUNEL staining. Changes in the number of CD68⁺ macrophages in placental tissues from PE patients were detected by immunofluorescent staining. The mRNA expression of the pro-inflammatory cytokines tumor necrosis factor alpha (TNF-α), interleukin (IL-1β), MCP-1, and proteins involved in extrinsic or intrinsic apoptosis signaling in the PE-like model was determined by qRT-PCR; immunofluorescent staining was used to detect the expression of TNF-α receptor (TNFR1), MCP-1 and apoptosis-related proteins.

KEY FINDINGS

Placental apoptosis was increased in both PE patients and the PE-like model, more macrophages infiltrated into placenta in PE patients. A significant upregulation in mRNA expression of TNF-α, IL-1β, MCP-1, and caspase 3, caspase 8, caspase 9 was found in the PE-like rats compared to the control animals, the immunoreactivity of placental MCP-1, TNFR1, and apoptosis-related proteins (caspase 3, caspase 8, caspase 9, Bax) was also enhanced; nicotine treatment significantly reversed those changes.

SIGNIFICANCE

Our data suggests that the protective effects of nicotine are associated with inhibiting placenta inflammation and apoptosis, and nicotine might be a potentially therapeutic candidate for preventing preeclampsia.

Placental transcriptome profile of women with sickle cell disease reveals differentially expressed genes involved in migration, trophoblast differentiation and inflammation

Sickle cell disease (SCD) is a group of disorders whose common characteristic is the presence of hemoglobin (Hb) S in erythrocytes. The main consequence of this abnormality is vaso-occlusion, which can affect almost all organs including the placenta. This study aimed to evaluate the gene expression profile in placentas of women with SCD by means of total RNA sequencing. For this, we proposed a case-control study, with three groups of pregnant women: HbSS (n = 10), HbSC (n = 14) and HbAA (n = 21). The results showed differences in expression in a number of genes such as NOS2 (fold change, FC = 4.52), HLAG (FC = 5.56), ASCL2 (FC = 3.61), CXCL10 (FC = -3.66) and IL1R2 (FC = 3.92) for the HbSC group and S100A8 (FC = -3.82), CPXM2 (FC = 4.57), CXCL10 (FC = -4.59), CXCL11 (FC = -3.72) and CAMP (FC = -4.55) for the HbSS group. Differentially expressed genes are mainly associated with migration, trophoblast differentiation and inflammation. The causes leading to altered gene expression in placentas of sickle cell patients are not fully understood, but the presence of intravascular hemolysis and vaso-occlusion, with cycles of ischemia and reperfusion, may contribute to the emergence of an environment which can be very harmful for placental physiology, altering the nutrient supply and metabolic exchange for fetal growth.