Adverse Maternal Environment Research Articles

Circulating cytokines and alarmins associated with placental inflammation in high-risk pregnancies.

ProblemInflammation during pregnancy has devastating consequences for the placenta and fetus. These events are incompletely understood, thereby hampering screening and treatment.Method of studyThe inflammatory profile of villous tissue was studied in pregnancies at high-risk of placental dysfunction and compared to uncomplicated pregnancies. The systemic inflammatory profile was assessed in matched maternal serum samples in cases of reduced fetal movements (RFM).ResultsPlacentas from RFM pregnancies had a unique inflammatory profile characterized by increased interleukin (IL)-1 receptor antagonist and decreased IL-10 expression, concomitant with increased numbers of placental macrophages. This aberrant cytokine profile was evident in maternal serum in RFM, as were increased levels of alarmins (uric acid, HMGB1, cell-free fetal DNA).ConclusionThis distinct inflammatory profile at the maternal-fetal interface, mirrored in maternal serum, could represent biomarkers of placental inflammation and could offer novel therapeutic options to protect the placenta and fetus from an adverse maternal environment.

Gestational hypertension and the developmental origins of cardiac hypertrophy and diastolic dysfunction

The developmental origins of health and disease refer to the theory that adverse maternal environments influence fetal development and the risk of cardiovascular disease in adulthood. We used the chronically hypertensive atrial natriuretic peptide knockout (ANP-/-) mouse as a model of gestational hypertension, and attempted to determine the effect of gestational hypertension on left ventricular (LV) structure and function in adult offspring. We crossed normotensive ANP+/+ females with ANP-/- males (yielding ANP+/-(WT) offspring) and hypertensive ANP-/- females with ANP+/+ males (yielding ANP+/-(KO) offspring). Cardiac gene expression was measured using real-time quantitative PCR. Cardiac function was assessed using echocardiography. Daily injections of isoproterenol (ISO) were used to induce cardiac stress. Collagen deposition was assessed using picrosirius red staining. All mice were 10 weeks of age. Gestational hypertension resulted in significant LV hypertrophy in offspring, with no change in LV function. Treatment with ISO resulted in significant LV diastolic dysfunction with a restrictive filling pattern (increased E/A ratio and E/e') and interstitial myocardial fibrosis only in ANP+/-(KO) and not ANP+/-(WT) offspring. Gestational hypertension programs adverse LV structural and functional remodeling in offspring. These data suggest that adverse maternal environments may increase the risk of heart failure in offspring later in life.

How the Kidney Is Impacted by the Perinatal Maternal Environment to Develop Hypertension1

Environmental conditions during perinatal development such as maternal undernutrition, maternal glucocorticoids, placental insufficiency, and maternal sodium overload can program changes in renal Na(+) excretion leading to hypertension. Experimental studies indicate that fetal exposure to an adverse maternal environment may reduce glomerular filtration rate by decreasing the surface area of the glomerular capillaries. Moreover, fetal responses to environmental insults during early life that contribute to the development of hypertension may include increased expression of tubular apical or basolateral membrane Na(+) transporters and increased production of renal superoxide leading to enhanced Na(+) reabsorption. This review will address the role of these potential renal mechanisms in the fetal programming of hypertension in experimental models induced by maternal undernutrition, fetal exposure to glucocorticoids, placental insufficiency, and maternal sodium overload in the rat.

Maternal Undernutrition Programs Tissue-Specific Epigenetic Changes in the Glucocorticoid Receptor in Adult Offspring

Epidemiological data indicate that an adverse maternal environment during pregnancy predisposes offspring to metabolic syndrome with increased obesity, and type 2 diabetes. The mechanisms are still unclear although epigenetic modifications are implicated and the hypothalamus is a likely target. We hypothesized that maternal undernutrition (UN) around conception in sheep would lead to epigenetic changes in hypothalamic neurons regulating energy balance in the offspring, up to 5 years after the maternal insult. We found striking evidence of decreased glucocorticoid receptor (GR) promoter methylation, decreased histone lysine 27 trimethylation, and increased histone H3 lysine 9 acetylation in hypothalami from male and female adult offspring of UN mothers. These findings are entirely compatible with the increased GR mRNA and protein observed in the hypothalami. The increased GR predicted the decreased hypothalamic proopiomelanocortin expression and increased obesity that we observed in the 5-year-old adult males. The epigenetic and expression changes in GR were specific to the hypothalamus. Hippocampal GR mRNA and protein were decreased in UN offspring, whereas pituitary GR was altered in a sex-specific manner. In peripheral polymorphonuclear leukocytes there were no changes in GR methylation or protein, indicating that this epigenetic analysis did not predict changes in the brain. Overall, these results suggest that moderate changes in maternal nutrition, around the time of conception, signal life-long and tissue-specific epigenetic alterations in a key gene regulating energy balance in the hypothalamus.

The effects of prenatal and postnatal environmental interaction: Prenatal environmental adaptation hypothesis

Adverse antenatal maternal environments during pregnancy influence fetal development that consequently increases risks of mental health problems including psychiatric disorders in offspring. Therefore, behavioral and brain alterations caused by adverse prenatal environmental conditions are generally considered as deficits. In this article, we propose a novel hypothesis, along with summarizing a body of literatures supporting it, that fetal neurodevelopmental alterations, particularly synaptic network changes occurring in the prefrontal cortex, associated with adverse prenatal environmental conditions may be adaptation to cope with expected severe postnatal environments, and therefore, psychiatric disorders may be able to be understood as adaptive strategies against severe environmental conditions through evolution. It is hoped that the hypothesis presented in this article stimulates and opens a new venue on research toward understanding of biological mechanisms and therapeutic treatments of psychiatric disorders.

Differential gene body methylation and reduced expression of cell adhesion and neurotransmitter receptor genes in adverse maternal environment

Early life adversity, including adverse gestational and postpartum maternal environment, is a contributing factor in the development of autism, attention deficit hyperactivity disorder (ADHD), anxiety and depression but little is known about the underlying molecular mechanism. In a model of gestational maternal adversity that leads to innate anxiety, increased stress reactivity and impaired vocal communication in the offspring, we asked if a specific DNA methylation signature is associated with the emergence of the behavioral phenotype. Genome-wide DNA methylation analyses identified 2.3% of CpGs as differentially methylated (that is, differentially methylated sites, DMSs) by the adverse environment in ventral-hippocampal granule cells, neurons that can be linked to the anxiety phenotype. DMSs were typically clustered and these clusters were preferentially located at gene bodies. Although CpGs are typically either highly methylated or unmethylated, DMSs had an intermediate (20–80%) methylation level that may contribute to their sensitivity to environmental adversity. The adverse maternal environment resulted in either hyper or hypomethylation at DMSs. Clusters of DMSs were enriched in genes that encode cell adhesion molecules and neurotransmitter receptors; some of which were also downregulated, indicating multiple functional deficits at the synapse in adversity. Pharmacological and genetic evidence links many of these genes to anxiety.

Severe Maternal Hyperglycemia Exacerbates the Development of Insulin Resistance and Fatty Liver in the Offspring on High Fat Diet

Background. Adverse maternal environments may predispose the offspring to metabolic syndrome in adulthoods, but the underlying mechanism has not been fully understood. Methods. Maternal hyperglycemia was induced by streptozotocin (STZ) injection while control (CON) rats received citrate buffer. Litters were adjusted to eight pups per dam and then weaned to standard diet. Since 13 weeks old, a subset of offspring from STZ and CON dams were switched to high fat diet (HFD) for another 13 weeks. Glucose and insulin tolerance tests (GTT and ITT) and insulin secretion assay were performed; serum levels of lipids and leptin were measured. Hepatic fat accumulation and islet area were evaluated through haematoxylin and eosin staining. Results. STZ offspring exhibited lower survival rate, lower birth weights, and growth inhibition which persisted throughout the study. STZ offspring on HFD showed more severe impairment in GTT and ITT, and more profound hepatic steatosis and more severe hyperlipidemia compared with CON-HFD rats. Conclusions. Offspring from diabetic dams would be prone to exhibit low birth weight and postnatal growth inhibition, but could maintain normal glucose tolerance and insulin sensitivity. HFD accelerates development of insulin resistance in the offspring of diabetic dams mainly via a compensatory response of islets.

Review: Sex and the Human Placenta: Mediating Differential Strategies of Fetal Growth and Survival

There are known sex specific differences in fetal and neonatal morbidity and mortality. There are also known differences in birthweight centile with males generally being larger than females at birth. These differences are generally ignored when studying obstetric complications of pregnancy and the mechanisms that confer these differences between the sexes are unknown. Current evidence suggests sex specific adaptation of the placenta may be central to the differences in fetal growth and survival. Our research examining pregnancies complicated by asthma has reported sexually dimorphic differences in fetal growth and survival with males adapting placental function to allow for continued growth in an adverse maternal environment while females reduce growth in an attempt to survive further maternal insults. We have reported sex differences in placental cytokine expression, insulin-like growth factor pathways and the placental response to cortisol in relation to the complication of asthma during pregnancy. More recently we have identified sex specific alterations in placental function in pregnancies complicated by preterm delivery which were associated with neonatal outcome and survival. We propose the sexually dimorphic differences in growth and survival of the fetus are mediated by the sex specific function of the human placenta. This review will present evidence supporting this hypothesis and will argue that to ignore the sex of the placenta is no longer sound scientific practice.

Maternal transmission of risk for atherosclerosis

In the last 20 years, an increasing amount of epidemiological and pathological evidence has become available illustrating the relationship between an adverse in-utero environment and increased risk of vascular disease in the offspring. It is now generally accepted that epigenetic phenomena, such as either DNA methylation or chromatin modifications or both mediate the long-term memory and thus developmental programming of cells and tissues. In utero, the placenta and fetus are exposed to the metabolic, antioxidant and pro-inflammatory and anti-inflammatory signals from the mother and will likely respond specifically. In the fetus, these responses may lead to permanent changes either in DNA methylation or chromatin modification or both and these changes may lead to increased atherosclerosis susceptibility in adulthood. However, the molecular mechanisms responsible for the translation of an adverse maternal environment into permanent epigenetic changes are poorly understood. In this review, we briefly summarize the possible signals crossing the placental barrier and discuss the molecular mechanisms of epigenetic programming in the developing fetus leading to increased athero-susceptibility of the vessel wall.