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

Is There a Relationship Between Prenatal Dexamethasone and Postnatal Fructose Overexposure and Testicular Development, Function, and Oxidative Stress Parameters in Rats?

Prenatal glucocorticoid overexposure alters the developmental program of fetal reproductive organs and results in numerous changes that can lead to various disorders later in life. Moderate fructose consumption during childhood and adolescence may impair the development and function of reproductive organs. The aim of this study was to investigate the effects of prenatal dexamethasone (Dx) exposure in combination with postnatal fructose overconsumption on testicular development and function in fetal and adult male rat offspring. Pregnant female rats were treated with a subcutaneous injection of Dx at a dose of 0.5 mg/kg/day on gestation days 16, 17, and 18, and the effects on fetal growth and testicular development were analyzed. Spontaneously born male offspring were fed 10% fructose in drinking water until the age of 3 months. Prenatal exposure to Dx led to a reduction in fetal weight and testicular volume. However, testicular development normalized by adulthood, with testosterone levels decreasing. After moderate fructose consumption, impaired redox homeostasis and structural changes in the testicles and decreased testosterone levels were observed, indicating reduced testicular function. The results suggest that the synergistic effect of prenatal Dx exposure and moderate postnatal fructose consumption leads to more deleterious changes in testicular tissue.

Dose-, stage- and sex- difference of prenatal prednisone exposure on placental morphological and functional development

Prednisone, a synthetic glucocorticoid, is commonly used to treat autoimmune diseases in pregnant women. However, some studies suggest that the use of prednisone during pregnancy may lead to adverse pregnancy outcomes. In this study, we established PPE mouse models at different doses (0.25, 0.5, 1.0 mg/kg·d) and different stages (whole pregnancy, early pregnancy and middle-late pregnancy) and determined outcomes on the placenta and fetus. The results of our study indicated that at the highest dose of 1 mg/kg PPE using a GD 0-18 dosing regime, PPE caused placental morphological changes measured as a decrease in placental weight relative to controls and a decrease in the placenta junctional zone (JZ)/labyrinth zone (LZ) ratio. No changes were observed on the fetuses for number of live, stillborn, and absorbed fetuses between the experimental groups and the control group. In the placentas at some doses, there were decreases in cell proliferation markers measured at the RNA and protein level by Western blot and increased apoptosis. Measures of gene expression at the mRNA level showed altered nutrients (including glucose, amino acid, and cholesterol) transport gene expressions with the most significant change associated with the male placentas at high-dose and whole pregnancy PPE group. It was further found that PPE led to the inhibition of the insulin-like growth factor 2 (IGF2)/insulin-like growth factor 1 receptor (IGF1R) signaling pathway, which was well correlated with the indicators of cell proliferation, syncytialization and nutrient (glucose and amino acid) transport indices. In conclusion, PPE can alter placental morphology and nutrient transport function, with differences in effect related to dose, stage and gender. Differential gene expressions measured for genes of the IGF2/IGF1R signaling pathway suggested this pathway may be involved in the effects seen with PPE. This study provides a theoretical and experimental basis for enhancing the understanding of the effects of prednisone use on placenta during human pregnancy but does not currently raise concerns for human use as effects were not seen on the fetuses and while the effects on cell proliferation are informative they were inconsistent and the differential effects on female and male placentas unexplained suggesting that further work is required to elucidate if these findings have relevance for human use of PPE during pregnancy.

Developmental programming of tissue-resident macrophages

Macrophages are integral components of the innate immune system that colonize organs early in development and persist into adulthood through self-renewal. Their fate, whether they are replaced by monocytes or retain their embryonic origin, depends on tissue type and integrity. Macrophages are influenced by their environment, a phenomenon referred to as developmental programming. This influence extends beyond the local tissue microenvironment and includes soluble factors that can reach the macrophage niche. These factors include metabolites, antibodies, growth factors, and cytokines, which may originate from maternal diet, lifestyle, infections, or other developmental triggers and perturbations. These influences can alter macrophage transcriptional, epigenetic, and metabolic profiles, affecting cell-cell communication and tissue integrity. In addition to their crucial role in tissue immunity, macrophages play vital roles in tissue development and homeostasis. Consequently, developmental programming of these long-lived cells can modulate tissue physiology and pathology throughout life. In this review, we discuss the ontogeny of macrophages, the necessity of developmental programming by the niche for macrophage identity and function, and how developmental perturbations can affect the programming of macrophages and their subtissular niches, thereby influencing disease onset and progression in adulthood. Understanding these effects can inform targeted interventions or preventive strategies against diseases. Finally, understanding the consequences of developmental programming will shed light on how maternal health and disease may impact the well-being of future generations.

To boldly go where no microRNAs have gone before: spaceflight impact on risk for small-for-gestational-age infants

In the era of renewed space exploration, comprehending the effects of the space environment on human health, particularly for deep space missions, is crucial. While extensive research exists on the impacts of spaceflight, there is a gap regarding female reproductive risks. We hypothesize that space stressors could have enduring effects on female health, potentially increasing risks for future pregnancies upon return to Earth, particularly related to small-for-gestational-age (SGA) fetuses. To address this, we identify a shared microRNA (miRNA) signature between SGA and the space environment, conserved across humans and mice. These miRNAs target genes and pathways relevant to diseases and development. Employing a machine learning approach, we identify potential FDA-approved drugs to mitigate these risks, including estrogen and progesterone receptor antagonists, vitamin D receptor antagonists, and DNA polymerase inhibitors. This study underscores potential pregnancy-related health risks for female astronauts and proposes pharmaceutical interventions to counteract the impact of space travel on female health.

DNA methylation-mediated 11βHSD2 downregulation drives the increases in angiotensin-converting enzyme and angiotensin II within preeclamptic placentas

Preeclampsia (PE) is a complex human-specific complication frequently associated with placental pathology. The local renin-angiotensin system (RAS) in the human placenta, which plays a crucial role in regulating placental function, has been extensively documented. Glucocorticoids (GCs) are a class of steroid hormones. PE cases often have abnormalities in GCs levels and placental GCs barrier. Despite extensive speculation, there is currently no robust evidence indicating that GCs regulate placental RAS. This study aims to investigate these potential relationships. Plasma and placental samples were collected from both normal and PE pregnancies. The levels of angiotensin-converting enzyme (ACE), angiotensin II (Ang II), cortisol, and 11β-hydroxysteroid dehydrogenases (11βHSD) were analyzed. In PE placentas, cortisol, ACE, and Ang II levels were elevated, while 11βHSD2 expression was reduced. Interestingly, a positive correlation was observed between ACE and cortisol levels in the placenta. A significant inverse correlation was found between the methylation statuses within the 11βHSD2 gene promoter and its expression, meanwhile, 11βHSD2 expression was negatively correlated with cortisol and ACE levels. In vitro experiments using placental trophoblast cells confirmed that active GCs can stimulate ACE transcription and expression through the GR pathway. Furthermore, 11βHSD2 knockdown could enhance this activating effect. An in vivo study using a rat model of intrauterine GCs overexposure during mid-to-late gestation suggested that excess GCs in utero lead to increased ACE and Ang II levels in the placenta. Collectively, this study provides the first evidence of the relationships between 11βHSD2 expression, GCs barrier, ACE, and Ang II levels in the placenta. It not only contributes to understanding the pathological features of the placental GCs barrier and RAS under PE conditions, also provides important information for revealing the pathological mechanism of PE.

Identification of biomarkers and sex differences in the placenta of fetal growth restriction

AIM

Fetal growth restriction (FGR) can lead to short-term and long-term impairments in the fetus. The placenta functions as an exchanger for substance transport, playing a critical role in fetal growth. However, the mechanism from the placental standpoint is still not fully understood. In this study, we aimed to investigate the pathophysiological mechanisms in the placenta that mediated the development of FGR and sex differences.

METHODS

We analyzed the gene expression profiles of GSE100415 containing specific normotensive FGR placental samples and GSE114691 with canonical samples using three different methods, differentially expressed gene analysis, weighted gene co-expression network analysis, and gene set enrichment analysis. Gene enrichment was performed, including the gene ontology and pathway from the Kyoto Encyclopedia of Genes and Genomes. The important process was then validated in pregnant Wistar rats subcutaneously administered dexamethasone (0.2 mg/kg/d) or saline from gestation Day 9 to 21.

RESULTS

Our results revealed little difference between the comparison of normal and normotensive FGR placental samples but confirmed the sex difference. Further analyses of the canonical samples identified the occurrence of vascular dysfunction, which was validated by the calculation of the vascular lumen area, showing that the vascular lumen in the FGR group was more than in the control. We also discovered 17 significantly expressed genes from the involved eigengenes.

CONCLUSION

Our study provides an important theoretical and experimental basis to reevaluate the development of FGR from the placental standpoint and suggests a series of biomarkers for future clinical use.

Glucocorticoid-induced thrombotic microangiopathy in paroxysmal nocturnal hemoglobinuria: A case report and review of literature

BACKGROUND

Thrombotic microangiopathy (TMA) is a group of disorders that converge on excessive platelet aggregation in the microvasculature, leading to consumptive thrombocytopenia, microangiopathic hemolysis and ischemic end-organ dysfunction. In predisposed patients, TMA can be triggered by many environmental factors. Glucocorticoids (GCs) can compromise the vascular endothelium. However, GC-associated TMA has rarely been reported, which may be due to the lack of awareness of clinicians. Given the high frequency of thrombocytopenia during GC treatment, particular attention should be given to this potentially fatal complication.

CASE SUMMARY

An elderly Chinese man had a 12-year history of aplastic anemia (AA) and a 3-year history of paroxysmal nocturnal hemoglobinuria (PNH). Three months earlier, methylprednisolone treatment was initiated at 8 mg/d and increased to 20 mg/d to alleviate complement-mediated hemolysis. Following GC treatment, his platelet counts and hemoglobin levels rapidly decreased. After admission to our hospital, the dose of methylprednisolone was increased to 60 mg/d in an attempt to enhance the suppressive effect. However, increasing the GC dose did not alleviate hemolysis, and his cytopenia worsened. Morphological evaluation of the marrow smears revealed increased cellularity with an increased percentage of erythroid progenitors without evident dysplasia. Cluster of differentiation (CD)55 and CD59 expression was significantly decreased on erythrocytes and granulocytes. In the following days, platelet transfusion was required due to severe thrombocytopenia. Observation of platelet transfusion refractoriness indicated that the exacerbated cytopenia may have been caused by the development of TMA due to GC treatment because the transfused platelet concentrates had no defects in glycosylphosphatidylinositol-anchored proteins. We examined blood smears and found a small number of schistocytes, dacryocytes, acanthocytes and target cells. Discontinuation of GC treatment resulted in rapidly increased platelet counts and steady increases in hemoglobin levels. The patient’s platelet counts and hemoglobin levels returned to the levels prior to GC treatment 4 weeks after GC discontinuation.

CONCLUSION

GCs can drive TMA episodes. When thrombocytopenia occurs during GC treatment, TMA should be considered, and GCs should be discontinued.

Cholic acid exposure during late pregnancy causes placental dysfunction and fetal growth restriction by reactive oxygen species-mediated activation of placental GCN2/eIF2α pathway

Epidemiological studies suggest that fetal growth restriction (FGR) caused by gestational cholestasis is associated with elevated serum cholic acid (CA). Here, we explore the mechanism by which CA induces FGR. Pregnant mice except controls were orally administered with CA daily from gestational day 13 (GD13) to GD17. Results found that CA exposure decreased fetal weight and crown-rump length, and increased the incidence of FGR in a dose-dependent manner. Furthermore, CA caused placental glucocorticoid (GC) barrier dysfunction via down-regulating the protein but not the mRNA level of placental 11β-Hydroxysteroid dehydrogenase-2 (11β-HSD2). Additionally, CA activated placental GCN2/eIF2α pathway. GCN2iB, an inhibitor of GCN2, significantly inhibited CA-induced down-regulation of 11β-HSD2 protein. We further found that CA caused excessive reactive oxygen species (ROS) production and oxidative stress in mouse placentas and human trophoblasts. NAC significantly rescued CA-induced placental barrier dysfunction by inhibiting activation of GCN2/eIF2α pathway and subsequent down-regulation of 11β-HSD2 protein in placental trophoblasts. Importantly, NAC rescued CA-induced FGR in mice. Overall, our results suggest that CA exposure during late pregnancy induces placental GC barrier dysfunction and subsequent FGR may be via ROS-mediated placental GCN2/eIF2α activation. This study provides valuable insight for understanding the mechanism of cholestasis-induced placental dysfunction and subsequent FGR.

Programming of Vascular Dysfunction by Maternal Stress: Immune System Implications

A growing body of evidence highlights that several insults during pregnancy impact the vascular function and immune response of the male and female offspring. Overactivation of the immune system negatively influences cardiovascular function and contributes to cardiovascular disease. In this review, we propose that modulation of the immune system is a potential link between prenatal stress and offspring vascular dysfunction. Glucocorticoids are key mediators of stress and modulate the inflammatory response. The potential mechanisms whereby prenatal stress negatively impacts vascular function in the offspring, including poor hypothalamic–pituitary–adrenal axis regulation of inflammatory response, activation of Th17 cells, renin–angiotensin–aldosterone system hyperactivation, reactive oxygen species imbalance, generation of neoantigens and TLR4 activation, are discussed. Alterations in the immune system by maternal stress during pregnancy have broad relevance for vascular dysfunction and immune-mediated diseases, such as cardiovascular disease.