Increased production of inflammatory cytokines and activation of microglia in the fetal brain of preeclamptic mice induced by angiotensin II.

Preeclampsia (PE) is a hypertensive obstetric disorder with poor prognosis for both the mother and offspring. Infants born to mothers with PE are known to be at increased risk of developing higher brain dysfunction, such as autism. However, how maternal PE can affect the environment in the fetal brain has not been fully elucidated. Here, we examined the impact of PE on the fetal brain in a mouse model of PE induced by angiotensin II (Ang II), focusing on changes in the inflammatory condition. We confirmed that pregnant mice which were continuously administered Ang II exhibited PE phenotypes, including high blood pressure, proteinuria, and fetal growth restriction. Quantitative RT-PCR analysis demonstrated that the brain of fetuses on embryonic day 17.5 (E17.5) in the Ang II-administered pregnant mice showed increased expression of cytokines, interleukin (IL)- 6, IL-17a, tumor necrosis factor-α, interferon-γ, IL-12, IL-4, and IL-10. Immunohistochemical analysis over a wide area, from the tip of the frontal lobe to the posterior cerebral end, on E17.5 revealed that the microglia in the fetal brain of the Ang II-administered group displayed higher solidity and circularity than those of the control group, indicating that the microglia had transformed to an amoeboid morphology and were activated. Our findings suggest that maternal PE may cause altered inflammatory conditions in the fetal brain, which might be associated with the pathological mechanism connecting maternal PE and brain dysfunction in the offspring.

Exposure to GABAA Receptor Antagonist Picrotoxin in Pregnant Mice Causes Autism-Like Behaviors and Aberrant Gene Expression in Offspring.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that is characterized by impairments in social interaction and restricted/repetitive behaviors. The neurotransmitter γ-aminobutyric acid (GABA) through GABAA receptor signaling in the immature brain plays a key role in the development of neuronal circuits. Excitatory/inhibitory imbalance in the mature brain has been investigated as a pathophysiological mechanism of ASD. However, whether and how disturbances of GABA signaling in embryos that are caused by GABAA receptor inhibitors cause ASD-like pathophysiology are poorly understood. The present study examined whether exposure to the GABAA receptor antagonist picrotoxin causes ASD-like pathophysiology in offspring by conducting behavioral tests from the juvenile period to adulthood and performing gene expression analyses in mature mouse brains. Here, we found that male mice that were prenatally exposed to picrotoxin exhibited a reduction of active interaction time in the social interaction test in both adolescence and adulthood. The gene expression analyses showed that picrotoxin-exposed male mice exhibited a significant increase in the gene expression of odorant receptors. Weighted gene co-expression network analysis showed a strong correlation between social interaction and enrichment of the "odorant binding" pathway gene module. Our findings suggest that exposure to a GABAA receptor inhibitor during the embryonic period induces ASD-like behavior, and impairments in odorant function may contribute to social deficits in offspring.

Influence of Prenatal Drug Exposure, Maternal Inflammation, and Parental Aging on the Development of Autism Spectrum Disorder.

Autism spectrum disorder (ASD) affects reciprocal social interaction and produces abnormal repetitive, restrictive behaviors and interests. The diverse causes of ASD are divided into genetic alterations and environmental risks. The prevalence of ASD has been rising for several decades, which might be related to environmental risks as it is difficult to consider that the prevalence of genetic disorders related to ASD would increase suddenly. The latter includes (1) exposure to medications, such as valproic acid (VPA) and selective serotonin reuptake inhibitors (SSRIs) (2), maternal complications during pregnancy, including infection and hypertensive disorders of pregnancy, and (3) high parental age. Epidemiological studies have indicated a pathogenetic role of prenatal exposure to VPA and maternal inflammation in the development of ASD. VPA is considered to exert its deleterious effects on the fetal brain through several distinct mechanisms, such as alterations of γ-aminobutyric acid signaling, the inhibition of histone deacetylase, the disruption of folic acid metabolism, and the activation of mammalian target of rapamycin. Maternal inflammation that is caused by different stimuli converges on a higher load of proinflammatory cytokines in the fetal brain. Rodent models of maternal exposure to SSRIs generate ASD-like behavior in offspring, but clinical correlations with these preclinical findings are inconclusive. Hypertensive disorders of pregnancy and advanced parental age increase the risk of ASD in humans, but the mechanisms have been poorly investigated in animal models. Evidence of the mechanisms by which environmental factors are related to ASD is discussed, which may contribute to the development of preventive and therapeutic interventions for ASD.

Elevation of maternal serum sFlt-1 in pregnancy with mirror syndrome caused by fetal cardiac failure.

Mirror syndrome (MS) is characterized by the combination of maternal generalized edema, fetal hydrops and placental hypertrophy. A shift of the serum placenta-derived angiogenic factor like sFlt-1 in MS is similar to that in pre-eclampsia (PE). We experienced a MS case caused by cardiac myopathy in the fetus with normal cardiac structure. A 27-year-old primiparous woman at 28 weeks of gestation had systemic edema without hypertension and proteinuria. Her symptoms rapidly disappeared after delivery. Compared with previously reported MS cases with maternal hypertension or proteinuria, the serum sFlt-1 level was lower in our case. Severity of maternal symptoms in MS might be paralleled with the serum sFlt-1 level. Additionally, serum hCG level in MS is much higher than that in PE. Maternal edema rather than hypertension and proteinuria can be more remarkable in MS compared with PE. It can be potentially explained by increased serum hCG level.