Neurodevelopmental consequences in offspring of mothers with preeclampsia during pregnancy: underlying biological mechanism via imprinting genes.

PURPOSE: Preeclampsia is known to be a leading cause of mortality and morbidity among mothers and their infants. Approximately 3-8% of all pregnancies in the US are complicated by preeclampsia and another 5-7% by hypertensive symptoms. However, less is known about its long-term influence on infant neurobehavioral development. The current review attempts to demonstrate new evidence for imprinting gene dysregulation caused by hypertension, which may explain the link between maternal preeclampsia and neurocognitive dysregulation in offspring. METHOD: Pub Med and Web of Science databases were searched using the terms "preeclampsia," "gestational hypertension," "imprinting genes," "imprinting dysregulation," and "epigenetic modification," in order to review the evidence demonstrating associations between preeclampsia and suboptimal child neurodevelopment, and suggest dysregulation of placental genomic imprinting as a potential underlying mechanism. RESULTS: The high mortality and morbidity among mothers and fetuses due to preeclampsia is well known, but there is little research on the long-term biological consequences of preeclampsia and resulting hypoxia on the fetal/child neurodevelopment. In the past decade, accumulating evidence from studies that transcend disciplinary boundaries have begun to show that imprinted genes expressed in the placenta might hold clues for a link between preeclampsia and impaired cognitive neurodevelopment. A sudden onset of maternal hypertension detected by the placenta may result in misguided biological programming of the fetus via changes in the epigenome, resulting in suboptimal infant development. CONCLUSION: Furthering our understanding of the molecular and cellular mechanisms through which neurodevelopmental trajectories of the fetus/infant are affected by preeclampsia and hypertension will represent an important first step toward preventing adverse neurodevelopment in infants.

Placental PHLDA2 expression is increased in cases of fetal growth restriction following reduced fetal movements.

BACKGROUND: Maternal perception of reduced fetal movements (RFM) is associated with increased risk of fetal growth restriction (FGR) and stillbirth, mediated by placental insufficiency. The maternally expressed imprinted gene PHLDA2 controls fetal growth, placental development and placental lactogen production in a mouse model. A number of studies have also demonstrated abnormally elevated placental PHLDA2 expression in human growth restricted pregnancies. This study examined whether PHLDA2 was aberrantly expressed in placentas of RFM pregnancies resulting in delivery of an FGR infant and explored a possible relationship between PHLDA2 expression and placental lactogen release from the human placenta. METHODS: Villous trophoblast samples were obtained from a cohort of women reporting RFM (N = 109) and PHLDA2 gene expression analysed. hPL levels were assayed in the maternal serum (N = 74). RESULTS: Placental PHLDA2 expression was significantly 2.3 fold higher in RFM pregnancies resulting in delivery of an infant with FGR (p < 0.01), with highest levels of PHLDA2 expression in the most severe cases. Placental PHLDA2 expression was associated with maternal serum hPL levels (r = -0.30, p = 0.008, n = 74) although this failed to reach statistical significance in multiple linear regression analysis controlling for birth weight (p = 0.07). CONCLUSIONS: These results further highlight a role for placental PHLDA2 in poor perinatal outcomes, specifically FGR associated with RFM. Furthermore, this study suggests a potential relationship between placental PHLDA2 expression and hPL production by the placenta, an association that requires further investigation in a larger cohort.