Degree of fetal growth restriction associated with schizophrenia risk in a national cohort

Children's early signs and developmental trajectories of psychotic-like experiences

INTRODUCTION

Children who experience persistent psychotic-like experiences (PLEs) are at a higher risk of developing psychotic disorder later in life. The developmental trajectories of PLEs are influenced by various factors. Therefore, it is important to identify early characteristics that can distinguish and predict between different developmental trajectories of PLEs.

METHODS

Using PLEs scores from the Adolescent Brain Cognitive Development (ABCD) data across three waves, we categorized participants into five distinct PLEs trajectories groups: persistent group (n = 47), remitting group (n = 185), increasing group (n = 117), remittent group (n = 21), and no PLEs group (n = 4,476). We utilized linear mixed-effect models and generalized linear mixed-effect models to examine the differences in baseline characteristics, including psychological and behavioral problems, suicidality, trauma experiences, developmental milestones, cognitive function, physical health, family income, family history of mental illness, and brain structureamong these PLEs trajectory groups.

RESULTS

We found that psychological and behavioral problems (such as DSM-oriented scales/externalizing/ADHD/social/attention/thought problems) assessed by the Child Behavior Checklist (CBCL) were associated with all PLEs groups. The persistent PLEs group had greater ADHD/social/thought problems and suicidal behavior compared to the remitting PLEs group. Comparing with the no PLEs group, poor cognitive function, abnormal brain structure (such as temporal lobe and supramarginal gyrus), more trauma experiences, and lower family income were found in only one of the PLEs groups, but not all PLEs groups.

CONCLUSION

The development of PLEs is accompanied by changes in many domains, implying a dynamic and complex developmental process. Given that psychological and behavioral problems can predict the emergence of PLEs at any time and can be regarded as risk factors for persistent PLEs, thereby enabling early precisely interventions, it is important to place greater emphasis on assessing psychological and behavioral problems.

Short- and Long-Term Outcomes of Preeclampsia in Offspring: Review of the Literature

Preeclampsia is a multisystemic clinical syndrome characterized by the appearance of new-onset hypertension and proteinuria or hypertension and end organ dysfunction even without proteinuria after 20 weeks of pregnancy or postpartum. Residing at the severe end of the spectrum of the hypertensive disorders of pregnancy, preeclampsia occurs in 3 to 8% of pregnancies worldwide and is a major cause of maternal and perinatal morbidity and mortality, accounting for 8-10% of all preterm births. The mechanism whereby preeclampsia increases the risk of the neurodevelopmental, cardiovascular, and metabolic morbidity of the mother's offspring is not well known, but it is possible that the preeclamptic environment induces epigenetic changes that adversely affect developmental plasticity. These developmental changes are crucial for optimal fetal growth and survival but may lead to an increased risk of chronic morbidity in childhood and even later in life. The aim of this review is to summarize both the short- and long-term effects of preeclampsia on offspring based on the current literature.

Schizophrenia and obesity: May the gut microbiota serve as a link for the pathogenesis?

Schizophrenia (SZ) places a tremendous burden on public health as one of the leading causes of disability and death. SZ patients are more prone to developing obesity than the general population from the clinical practice. The development of obesity frequently causes poor psychiatric outcomes in SZ patients. In turn, maternal obesity during pregnancy has been associated with an increased risk of SZ in offspring, suggesting that these two disorders may have shared neuropathological mechanisms. The gut microbiota is well known to serve as a major regulator of bidirectional interactions between the central nervous system and the gastrointestinal tract. It also plays a critical role in maintaining physical and mental health in humans. Recent studies have shown that the dysbiosis of gut microbiota is intimately associated with the onset of SZ and obesity through shared pathophysiological mechanisms, particularly the stimulation of immune inflammation. Therefore, gut microbiota may serve as a common biological basis for the etiology in both SZ and obesity, and the perturbed gut-brain axis may therefore account for the high prevalence of obesity in patients with SZ. On the basis of these findings, this review provides updated perspectives and intervention approaches on the etiology, prevention, and management of obesity in SZ patients by summarizing the recent findings on the role of gut microbiota in the pathogenesis of SZ and obesity, highlighting the role of gut-derived inflammation.

Environmental Risk Factors and Cognitive Outcomes in Psychosis: Pre-, Perinatal, and Early Life Adversity

Risk for psychosis begins to accumulate as early as the fetal period through exposure to obstetric complications like fetal hypoxia, maternal stress, and prenatal infection. Stressors in the postnatal period, such as childhood trauma, peer victimization, and neighborhood-level adversity, further increase susceptibility for psychosis. Cognitive difficulties are among the first symptoms to emerge in individuals who go on to develop a psychotic disorder. We review the relationship between pre-, perinatal, and early childhood adversities and cognitive outcomes in individuals with psychosis. Current evidence shows that the aforementioned environmental risk factors may be linked to lower overall intelligence and executive dysfunction, beginning in the premorbid period and persisting into adulthood in individuals with psychosis. It is likely that early life stress contributes to cognitive difficulties in psychosis through dysregulation of the body's response to stress, causing changes such as increased cortisol levels and chronic immune activation, which can negatively impact neurodevelopment. Intersectional aspects of identity (e.g., sex/gender, race/ethnicity), as well as gene-environment interactions, likely inform the developmental cascade to cognitive difficulties throughout the course of psychotic disorders and are reviewed below. Prospective studies of birth cohorts will serve to further clarify the relationship between early-life environmental risk factors and cognitive outcomes in the developmental course of psychotic disorders. Specific methodological recommendations are provided for future research.

Perinatal iron deficiency as an early risk factor for schizophrenia

Growing evidence indicates that a suboptimal intrauterine environment confers risk for schizophrenia. The developmental model of schizophrenia posits that aberrant brain growth during early brain development and adolescence may interact to contribute to this psychiatric disease in adulthood. Although a variety of factors may perturb the environment of the developing fetus and predispose for schizophrenia later, a common mechanism has yet to be elucidated. Micronutrient deficiencies during the perinatal period are known to induce potent effects on brain development by altering neurodevelopmental processes. Iron is an important candidate nutrient to consider because of its role in energy metabolism, monoamine synthesis, synaptogenesis, myelination, and the high prevalence of iron deficiency (ID) in the mother-infant dyad. Understanding the current state of science regarding perinatal ID as an early risk factor for schizophrenia is imperative to inform empirical work investigating the etiology of schizophrenia and develop prevention and intervention programs. In this narrative review, we focus on perinatal ID as a common mechanism underlying the fetal programming of schizophrenia. First, we review the neural aberrations associated with perinatal ID that indicate risk for schizophrenia in adulthood, including disruptions in dopaminergic neurotransmission, hippocampal-dependent learning and memory, and sensorimotor gating. Second, we review the pathophysiology of perinatal ID as a function of maternal ID during pregnancy and use epidemiological and cohort studies to link perinatal ID with risk of schizophrenia. Finally, we review potential confounding phenotypes, including nonanemic causes of perinatal brain ID and future risk of schizophrenia.

The Global Pregnancy Collaboration (CoLab) symposium on short- and long-term outcomes in offspring whose mothers had preeclampsia: A scoping review of clinical evidence

Preeclampsia is a maternal syndrome characterized by the new onset of hypertension after 20 weeks of gestation associated with multisystemic complications leading to high maternal and fetal/neonatal morbidity and mortality. However, sequelae of preeclampsia may extend years after pregnancy in both mothers and their children. In addition to the long-term adverse cardiovascular effects of preeclampsia in the mother, observational studies have reported elevated risk of cardiovascular, metabolic, cerebral and cognitive complications in children born from women with preeclampsia. Less clear is whether the association between maternal preeclampsia and offspring sequelae are causal, or to what degree the associations might be driven by fetal factors including impaired growth and the health of its placenta. Our discussion of these complexities in the 2018 Global Pregnancy Collaboration annual meeting prompted us to write this review. We aimed to summarize the evidence of an association between maternal preeclampsia and neurobehavioral developmental disorders in offspring in hopes of generating greater research interest in this important topic.

Educational attainment and mortality in schizophrenia

BACKGROUND

Individuals suffering from schizophrenia have a reduced life expectancy with cardiovascular disease (CVD) as a major contributor. Low educational attainment is associated with schizophrenia, as well as with all-cause and CVD mortality. However, it is unknown to what extent low educational attainment can explain the increased mortality in individuals with schizophrenia.

AIM

Here, we quantify associations between educational attainment and all-cause and CVD mortality in individuals with schizophrenia, and compare them with the corresponding associations in the general population.

METHOD

All Norwegian citizens born between January 1, 1925, and December 31, 1959, were followed up from January 1, 1990, to December 31, 2014. The total sample included 1,852,113 individuals, of which 6548 were registered with schizophrenia. We estimated hazard ratios (HR) for all-cause and CVD mortality with Cox models, in addition to life years lost. Educational attainment for index persons and their parents were included in the models.

RESULTS

In the general population individuals with low educational attainment had higher risk of all-cause (HR: 1.48 [95% CI: 1.47-1.49]) and CVD (HR: 1.59 [95% CI: 1.57-1.61]) mortality. In individuals with schizophrenia these estimates were substantially lower (all-cause: HR: 1.13 [95% CI: 1.05-1.21] and CVD: HR: 1.12 [95% CI: 0.98-1.27]). Low educational attainment accounted for 3.28 (3.21-3.35) life years lost in males and 2.48 (2.42-2.55) years in females in the general population, but was not significantly associated with life years lost in individuals with schizophrenia. Results were similar for parental educational attainment.

CONCLUSIONS

Our results indicate that while individuals with schizophrenia in general have lower educational attainment and higher mortality rates compared with the general population, the association between educational attainment and mortality is smaller in schizophrenia subjects than in the general population.

Term Birth Weight and Neurodevelopmental Outcomes

BACKGROUND

Preterm birth is an important risk factor for neurodevelopmental disabilities. The vast majority of these disabilities occur, however, among term births. The role of fetal growth restriction specifically among term babies has been incompletely described.

METHODS

We conducted a population-based study of term birth weight and its link to a range of neurodevelopmental outcomes using Norwegian health registries. To remove the influence of preterm birth, we restricted our analyses to 1.8 million singleton babies born during a narrow range of term gestational age (39-41 weeks). Babies with malformations were excluded. We adjusted analyses simply for year of birth, as further adjustments for sex, parity, maternal age, smoking, marital status, immigrant status, and parental education had trivial influence. An additional sibling analysis controlled for unmeasured family-based confounding.

RESULTS

The risk of neurodevelopmental disabilities at term steadily increased at birth weights lower than 3.5 kg. Using the category of 3.5-3.9 kg as the reference, the odds reached 25-fold for cerebral palsy at the smallest weights (95% confidence interval 8.0, 79), 16-fold for vision/hearing disability (4.0, 65), 11-fold for intellectual impairment (6.9, 17), 7-fold for schizophrenia (1.0, 50), 5.4-fold for epilepsy (2.6, 12), and 3.5-fold for autism spectrum (1.3, 9.4) and behavioral disorders including attention-deficit hyperactivity disorder (2.1, 5.4). Associations remained robust with sibling controls.

CONCLUSIONS

Reduced fetal growth is a powerful predictor of a wide variety of neurodevelopmental disabilities independent of preterm delivery.

Preeclampsia and Neurodevelopmental Outcomes: Potential Pathogenic Roles for Inflammation and Oxidative Stress?

Preeclampsia (PE) is a common and serious hypertensive disorder of pregnancy that occurs in approximately 3-5% of first-time pregnancies and is a well-known leading cause of maternal and neonatal mortality and morbidity. In recent years, there has been accumulating evidence that in utero exposure to PE acts as an environmental risk factor for various neurodevelopmental disorders, particularly autism spectrum disorder and ADHD. At present, the mechanism(s) mediating this relationship are uncertain. In this review, we outline the most recent evidence implicating a causal role for PE exposure in the aetiology of various neurodevelopmental disorders and provide a novel interpretation of neuroanatomical alterations in PE-exposed offspring and how these relate to their sub-optimal neurodevelopmental trajectory. We then postulate that inflammation and oxidative stress, two prominent features of the pathophysiology of PE, are likely to play a major role in mediating this association. The increased inflammation in the maternal circulation, placenta and fetal circulation in PE expose the offspring to both prenatal maternal immune activation-a risk factor for neurodevelopmental disorders, which has been well-characterised in animal models-and directly higher concentrations of pro-inflammatory cytokines, which adversely affect neuronal development. Similarly, the exaggerated oxidative stress in the mother, placenta and foetus induces the placenta to secrete factors deleterious to neurons, and exposes the fetal brain to directly elevated oxidative stress and thus adversely affects neurodevelopmental processes. Finally, we describe the interplay between inflammation and oxidative stress in PE, and how both systems interact to potentially alter neurodevelopmental trajectory in exposed offspring.

Quantifying myelin content in brain tissue using color Spatial Light Interference Microscopy (cSLIM)

Deficient myelination of the brain is associated with neurodevelopmental delays, particularly in high-risk infants, such as those born small in relation to their gestational age (SGA). New methods are needed to further study this condition. Here, we employ Color Spatial Light Interference Microscopy (cSLIM), which uses a brightfield objective and RGB camera to generate pathlength-maps with nanoscale sensitivity in conjunction with a regular brightfield image. Using tissue sections stained with Luxol Fast Blue, the myelin structures were segmented from a brightfield image. Using a binary mask, those portions were quantitatively analyzed in the corresponding phase maps. We first used the CLARITY method to remove tissue lipids and validate the sensitivity of cSLIM to lipid content. We then applied cSLIM to brain histology slices. These specimens are from a previous MRI study, which demonstrated that appropriate for gestational age (AGA) piglets have increased internal capsule myelination (ICM) compared to small for gestational age (SGA) piglets and that a hydrolyzed fat diet improved ICM in both. The identity of samples was blinded until after statistical analyses.

Perinatal biomarkers implying 'Developmental Origins of Health and Disease' consequences in intrauterine growth restriction

The intrauterine-growth-restricted (IUGR) state, particularly the asymmetric one, has been associated with 'Developmental Origins of Health and Disease' (DOHaD) consequences later in life. Several environmental factors, acting during the phase of foetal developmental plasticity interact with genotypic variation, 'programme' tissue function and change the capacity of the organism to cope with its environment. They may be responsible for chronic illness risk in adulthood. Detection of possible future DOHaD consequences at a very early age, by applying relevant biomarkers, is of utmost importance. This review focuses on biomarkers possibly predicting consequences from bone, psychoneural system and lung. Although no concrete biomarker has been identified for bone disorders in adulthood, reduced brain-derived neurotrophic factor (BDNF) concentrations in cord blood and BDNF DNA methylation might predict schizophrenia and possibly depression, bipolar disorder and autism. High surfactant protein D (SP-D) concentrations in cord blood of IUGR foetuses/neonates could point to structural lung immaturity, resulting to asthma and chronic obstructive pulmonary disease in adult life.

Neurodevelopmental Outcomes of Prenatal Preeclampsia Exposure

Preeclampsia is a dangerous hypertensive disorder of pregnancy with known links to negative child health outcomes. Here, we review epidemiological and basic neuroscience work from the past several decades linking prenatal preeclampsia to altered neurodevelopment. This work demonstrates increased rates of neuropsychiatric disorders [e.g., increased autism spectrum disorder, attention deficit hyperactivity disorder (ADHD)] in children of preeclamptic pregnancies, as well as increased rates of cognitive impairments [e.g., decreased intelligence quotient (IQ), academic performance] and neurological disease (e.g., stroke and epilepsy). We also review findings from multiple animal models of preeclampsia. Manipulation of key clinical preeclampsia processes in these models (e.g., placental hypoxia, immune dysfunction, angiogenesis, oxidative stress) causes various disruptions in offspring, including ones in white matter/glia, glucocorticoid receptors, neuroimmune outcomes, cerebrovascular structure, and cognition/behavior. This animal work implicates potentially high-yield targets that may be leveraged in the future for clinical application.

Maternal cortisol during pregnancy and offspring schizophrenia: Influence of fetal sex and timing of exposure

INTRODUCTION

Maternal stress during pregnancy has been repeatedly linked to increased risk for schizophrenia; however, no study has examined maternal cortisol during pregnancy and risk for the disorder. Study aims were to determine whether prenatal cortisol was associated with risk for schizophrenia and risk for an intermediate phenotype-decreased fetal growth-previously linked to prenatal cortisol and schizophrenia. Timing of exposure and fetal sex also were examined given previous findings.

METHODS

Participants were 64 cases diagnosed with schizophrenia spectrum disorders (SSD) and 117 controls from a prospective birth cohort study. Maternal cortisol was determined from stored sera from each trimester and psychiatric diagnoses were assessed from offspring using semi-structured interviews and medical records review.

RESULTS

Maternal cortisol during pregnancy was not associated with risk for offspring schizophrenia. There was a significant interaction between 3rd trimester cortisol and case status on fetal growth. Specifically, cases exposed to higher 3rd trimester maternal cortisol had significantly decreased fetal growth compared to controls. In addition, these findings were restricted to male offspring.

CONCLUSIONS

Our results indicate that higher prenatal cortisol is associated with an intermediate phenotype linked to schizophrenia, fetal growth, but only among male offspring who developed schizophrenia. Findings were consistent with evidence that schizophrenia genes may disrupt placental functioning specifically for male fetuses, as well as findings that males are more vulnerable to maternal cortisol during pregnancy. Finally, results suggest that examining fetal sex and intermediate phenotypes may be important in understanding the mechanisms involved in prenatal contributors to schizophrenia.

Lasting Effects of Intrauterine Exposure to Preeclampsia on Offspring and the Underlying Mechanism

Preeclampsia is a common pregnancy complication which can have adverse impact on both mother and baby. In addition to the short term effects, a large body of epidemiological evidence has found preeclampsia can exert long-lasting effects on mother and offspring. Studies suggest that offspring exposed to preeclampsia are at a higher risk of developing cardiovascular, metabolic, and neurological diseases, as well as other diseases. However, studies investigating the underlying mechanism are limited, the exact mechanism still remains unclear. In this study, we will review the epidemiological evidence and studies exploring the mechanism underlying long-term effects of preeclampsia on offspring. Further studies should be targeted at this field so as to implement effective clinical management to prevent the exposed offspring from potential diseases.

The Role of 11β-Hydroxy Steroid Dehydrogenase Type 2 in Glucocorticoid Programming of Affective and Cognitive Behaviours

Developmental exposure to stress hormones, i.e. glucocorticoids, is central to the process of prenatal programming of later-life health. Glucocorticoid overexposure, through stress or exogenous glucocorticoids, results in a reduced birthweight, as well as affective and neuropsychiatric outcomes in adults, combined with altered hypothalamus-pituitary-adrenal (HPA) axis activity. As such, glucocorticoids are tightly regulated during development through the presence of the metabolizing enzyme 11β-hydroxysteroid dehydrogenase type 2 (HSD2). HSD2 is highly expressed in 2 hubs during development, i.e. the placenta and the fetus itself, protecting the fetus from inappropriate glucocorticoid exposure early in gestation. Through manipulation of HSD2 expression in the mouse placenta and fetal tissues, we are able to determine the relative contribution of glucocorticoid exposure in each compartment. Feto-placental HSD2 deletion resulted in a reduced birthweight and the development of anxiety- and depression-like behaviours in adult mice. The placenta itself is altered by glucocorticoid overexposure, which causes reduced placental weight and vascular arborisation. Furthermore, altered flow and resistance in the umbilical vessels and modification of fetal heart function and development are observed. However, brain-specific HSD2 removal (HSD2BKO) also generated adult phenotypes of depressive-like behaviour and memory deficits, demonstrating the importance of fetal brain HSD2 expression in development. In this review we will discuss potential mechanisms underpinning early-life programming of adult neuropsychiatric disorders and the novel therapeutic potential of statins.

Preeclamptic placentae release factors that damage neurons: implications for foetal programming of disease

Prenatal development is a critical period for programming of neurological disease. Preeclampsia, a pregnancy complication involving oxidative stress in the placenta, has been associated with long-term health implications for the child, including an increased risk of developing schizophrenia and autism spectrum disorders in later life. To investigate if molecules released by the placenta may be important mediators in foetal programming of the brain, we analysed if placental tissue delivered from patients with preeclampsia secreted molecules that could affect cortical cells in culture. Application of culture medium conditioned by preeclamptic placentae to mixed cortical cultures caused changes in neurons and astrocytes that were related to key changes observed in brains of patients with schizophrenia and autism, including effects on dendrite lengths, astrocyte number as well as on levels of glutamate and γ-aminobutyric acid receptors. Treatment of the placental explants with an antioxidant prevented neuronal abnormalities. Furthermore, we identified that bidirectional communication between neurons and astrocytes, potentially via glutamate, is required to produce the effects of preeclamptic placenta medium on cortical cells. Analysis of possible signalling molecules in the placenta-conditioned medium showed that the secretion profile of extracellular microRNAs, small post-transcriptional regulators, was altered in preeclampsia and partially rescued by antioxidant treatment of the placental explants. Predicted targets of these differentially abundant microRNAs were linked to neurodevelopment and the placenta. The present study provides further evidence that the diseased placenta may release factors that damage cortical cells and suggests the possibility of targeted antioxidant treatment of the placenta to prevent neurodevelopmental disorders.

Fetal Origins of Mental Disorders? An Answer Based on Mendelian Randomization

The Barker hypothesis states that low birth weight (BW) is associated with higher risk of adult onset diseases, including mental disorders like schizophrenia, major depressive disorder (MDD), and attention deficit hyperactivity disorder (ADHD). The main criticism of this hypothesis is that evidence for it comes from observational studies. Specifically, observational evidence does not suffice for inferring causality, because the associations might reflect the effects of confounders. Mendelian randomization (MR) - a novel method that tests causality on the basis of genetic data - creates the unprecedented opportunity to probe the causality in the association between BW and mental disorders in observation studies. We used MR and summary statistics from recent large genome-wide association studies to test whether the association between BW and MDD, schizophrenia and ADHD is causal. We employed the inverse variance weighted (IVW) method in conjunction with several other approaches that are robust to possible assumption violations. MR-Egger was used to rule out horizontal pleiotropy. IVW showed that the association between BW and MDD, schizophrenia and ADHD is not causal (all p > .05). The results of all the other MR methods were similar and highly consistent. MR-Egger provided no evidence for pleiotropic effects biasing the estimates of the effects of BW on MDD (intercept = -0.004, SE = 0.005, p = .372), schizophrenia (intercept = 0.003, SE = 0.01, p = .769), or ADHD (intercept = 0.009, SE = 0.01, p = .357). Based on the current evidence, we refute the Barker hypothesis concerning the fetal origins of adult mental disorders. The discrepancy between our results and the results from observational studies may be explained by the effects of confounders in the observational studies, or by the existence of a small causal effect not detected in our study due to weak instruments. Our power analyses suggested that the upper bound for a potential causal effect of BW on mental disorders would likely not exceed an odds ratio of 1.2.

Preventing childhood and lifelong disability: Maternal dietary supplementation for perinatal brain injury

The majority of brain injuries that lead to cerebral palsy, developmental disability, and mental health disorders have their onset in utero. These lifelong conditions come with great economic and emotional burden as they impact function in nearly all domains of affected individuals' lives. Unfortunately, current therapeutic options are limited. There remains a focus on rescue, rehabilitation, and regeneration after the injury has occurred, rather than aiming to prevent the initial injury. Prevention would imply treating the mother during pregnancy to alter the fetal environment and in turn, treat the fetus. Fear of harming the developing fetus remains as a result of errors of the past such as the release of thalidomide. In this review, we outline evidence from animal studies and clinical trials that have explored maternal dietary supplementation with natural health products (including nutraceuticals and functional foods) for perinatal brain injury prevention. Namely, we discuss magnesium sulphate, creatine, choline, melatonin, resveratrol and broccoli sprouts/sulforaphane. Although clinical trials have only been completed in this realm for magnesium sulphate, results in animal models have been promising, suggesting that this is a productive avenue for further research. Natural health products may provide safe, effective, affordable, and easily accessible prevention of fetal brain injury and resulting lifelong disabilities.

Nutritional influences on brain development

There is increasing evidence from preclinical and human studies that nutrition in the late foetal and early neonatal period has a significant impact on neurodevelopment across the lifespan. Certain nutrients have particularly large effects in this time period, and their deficits cause greater long-term risk. The mechanisms by which nutrients influence early brain growth and the sensitive periods for when certain nutrients should be provided are being elucidated. Assessments of nutritional status that index brain growth and predict long-term development are important to assess the efficacy of early life nutritional therapies.

CONCLUSION

Optimizing nutrition during foetal and early postnatal life is a golden opportunity to impact neurodevelopment and brain function across the lifespan.

Atypical fetal development: Fetal alcohol syndrome, nutritional deprivation, teratogens, and risk for neurodevelopmental disorders and psychopathology

Accumulating evidence indicates that the fetal environment plays an important role in brain development and sets the brain on a trajectory across the life span. An abnormal fetal environment results when factors that should be present during a critical period of development are absent or when factors that should not be in the developing brain are present. While these factors may acutely disrupt brain function, the real cost to society resides in the long-term effects, which include important mental health issues. We review the effects of three factors, fetal alcohol exposure, teratogen exposure, and nutrient deficiencies, on the developing brain and the consequent risk for developmental psychopathology. Each is reviewed with respect to the evidence found in epidemiological and clinical studies in humans as well as preclinical molecular and cellular studies that explicate mechanisms of action.

Complex Trajectories of Brain Development in the Healthy Human Fetus

This study characterizes global and hemispheric brain growth in healthy human fetuses during the second half of pregnancy using three-dimensional MRI techniques. We studied 166 healthy fetuses that underwent MRI between 18 and 39 completed weeks gestation. We created three-dimensional high-resolution reconstructions of the brain and calculated volumes for left and right cortical gray matter (CGM), fetal white matter (FWM), deep subcortical structures (DSS), and the cerebellum. We calculated the rate of growth for each tissue class according to gestational age and described patterns of hemispheric growth. Each brain region demonstrated major increases in volume during the second half of gestation, the most pronounced being the cerebellum (34-fold), followed by FWM (22-fold), CGM (21-fold), and DSS (10-fold). The left cerebellar hemisphere, CGM, and DSS had larger volumes early in gestation, but these equalized by term. It has been increasingly recognized that brain asymmetry evolves throughout the human life span. Advanced quantitative MRI provides noninvasive measurements of early structural asymmetry between the left and right fetal brain that may inform functional and behavioral laterality differences seen in children and young adulthood.

Perinatal hypoxia as a risk factor for psychopathology later in life: the role of dopamine and neurotrophins

Brain development is influenced by various prenatal, intrapartum, and postnatal events which may interact with genotype to affect the neural and psychophysiological systems related to emotions, specific cognitive functions (e.g., attention, memory), and language abilities and thereby heighten the risk for psychopathology later in life. Fetal hypoxia (intrapartum oxygen deprivation), hypoxia-related obstetric complications, and hypoxia during the early neonatal period are major environmental risk factors shown to be associated with an increased risk for later psychopathology. Experimental models of perinatal hypoxia/ischemia (PHI) showed that fetal hypoxia-a consequence common to many birth complications in humans-results in selective long-term disturbances of the dopaminergic systems that persist in adulthood. On the other hand, neurotrophic signaling is critical for pre- and postnatal brain development due to its impact on the process of neuronal development and its reaction to perinatal stress. The aim of this review is (a) to summarize epidemiological data confirming an association of PHI with an increased risk of a range of psychiatric disorders from childhood through adolescence to adulthood, (b) to present immunohistochemical findings on human autopsy material indicating vulnerability of the dopaminergic neurons of the human neonate to PHI that could predispose infant survivors of PHI to dopamine-related neurological and/or cognitive deficits in adulthood, and

Pre-eclampsia and the risk of autism-spectrum disorder in offspring: meta-analysis

BACKGROUND

Evidence about the effect of intrauterine exposure to pre-eclampsia on offspring autism-spectrum disorder (ASD) is not well established. Aims To examine the association between pre-eclampsia and ASD.

METHOD

PubMed, Embase and PsycINFO databases were searched. Pooled relative risks (RR) with 95% confidence intervals were calculated. Subgroup and sensitivity analyses were performed. Heterogeneity was assessed using Cochran's Q- and the I 2-test. The presence of publication bias was evaluated by Egger's test and visual inspection of the symmetry in funnel plots.

RESULTS

Ten studies meet the inclusion criteria. The risk of ASD was 32% higher in offspring who had intrauterine exposure to pre-eclampsia compared with those not exposed (RR = 1.32, 95% CI 1.20-1.45). Sensitivity analysis revealed consistent pooled estimates ranging from RR = 1.30 (95% CI 1.17-1.44) to RR = 1.37 (95% CI 1.26-1.48). We found no significant heterogeneity and evidence of publication bias.

CONCLUSION

Pre-eclampsia increased the risk of ASD in offspring. The finding suggests a need for early screening for ASD in offspring of women with pre-eclampsia. Declaration of interest None.

Association between hypertensive disorders of pregnancy and the development of offspring mental and behavioural problems: A systematic review and meta-analysis

Hypertensive disorders of pregnancy are a major cause of maternal and offspring morbidity and mortality worldwide. However, its effect on offspring mental and behavioural disorders is unclear. The aim of this study is to provide the best scientific evidence on the association between hypertensive disorders of pregnancy and offspring mental and behavioural problems. We systematically searched Scopus, PubMed, Cochrane, EMBASE, CINAH and PsycINFO databases. A total of 23 studies (11 included in meta-analysis) were identified. Of the 23 studies included in this review, 15 studies found that hypertensive disorders of pregnancy had a negative impact for at least one mental or behavioural disorder. The pooled effect of 11 studies included in the meta-analysis showed that preeclampsia was associated with increased risk of offspring schizophrenia. However, we found inconclusive finding on the effect of hypertensive disorders of pregnancy and other mental and behavioural disorders. Further high quality, large sample, birth cohort studies are needed to further progress this area of research.

Association between hypertensive disorders of pregnancy and risk of autism in offspring: a systematic review and meta-analysis of observational studies

Background

Autism spectrum disorder (ASD) is a common severe pervasive neurodevelopmental disorder of undetermined etiology. Environmental exposures, especially pregnancy complications, have been increasingly recognized as a potential risk factor for ASD. Our aim was to (1) systematically evaluate the association between hypertensive disorders of pregnancy (HDP) and the risk of ASD in offspring, (2) specifically draw a subgroup analysis of disease severity in patients with HDP to achieve more sufficient evidence on this issue.

Results

A total of 21 studies were identified with more than 6.5 million participants, including 31,027 ASD probands. A comparative meta-analysis established that offspring born premature to HDP were significantly associated with ASD than matched controls (OR = 1.42, 95% CI: 1.34–1.50). Subgroup analysis of clinical classification include: (1) gestational hypertension, (2) pre-eclampsia, (3) chronic hypertension complicating pregnancy (CHP). The offspring of mothers with pre-eclampsia and CHP have slightly higher risk (OR = 1.43; OR = 1.48, respectively) of ASD than those of mothers with gestational hypertension (OR = 1.37). In consistence with most previous researches, higher ASD prevalence was observed in male than female (OR = 1.38), indicating a potential role for gender in the pathophysiology of ASD.

Materials and Methods

We conducted a systematic literature search on PubMed, EMBASE, Web of Science, PsycINFO database and China National Knowledge Infrastructure up to Jun. 2017. Statistical analysis was performed using Stata 10.0.

Conclusions

This meta-analysis implies a possible link between HDP and the risk of ASD in offspring. However, further investigation should be conducted to confirm this conclusion, and intensive prenatal surveillance and early prediction for ASD is needed.

Maternal high-fat diet programming of the neuroendocrine system and behavior

This article is part of a Special Issue "SBN 2014". Maternal obesity, metabolic state, and diet during gestation have profound effects on offspring development. The prevalence of neurodevelopmental and mental health disorders has risen rapidly in the last several decades in parallel with the rise in obesity rates. Evidence from epidemiological studies indicates that maternal obesity and metabolic complications increase the risk of offspring developing behavioral disorders such as attention deficit hyperactivity disorder (ADHD), autism spectrum disorders (ASD), and schizophrenia. Animal models show that a maternal diet high in fat similarly disrupts behavioral programming of offspring, with animals showing social impairments, increased anxiety and depressive behaviors, reduced cognitive development, and hyperactivity. Maternal obesity, metabolic conditions, and high fat diet consumption increase maternal leptin, insulin, glucose, triglycerides, and inflammatory cytokines. This leads to increased risk of placental dysfunction, and altered fetal neuroendocrine development. Changes in brain development that likely contribute to the increased risk of behavioral and mental health disorders include increased inflammation in the brain, as well as alterations in the serotonergic system, dopaminergic system and hypothalamic-pituitary-adrenal (HPA) axis.

The role of maternal obesity in the risk of neuropsychiatric disorders

Recent evidence indicates that perinatal exposure to maternal obesity, metabolic disease, including diabetes and hypertension, and unhealthy maternal diet has a long-term impact on offspring behavior and physiology. During the past three decades, the prevalence of both obesity and neuropsychiatric disorders has rapidly increased. Epidemiologic studies provide evidence that maternal obesity and metabolic complications increase the risk of attention deficit hyperactivity disorder (ADHD), autism spectrum disorders, anxiety, depression, schizophrenia, eating disorders (food addiction, anorexia nervosa, and bulimia nervosa), and impairments in cognition in offspring. Animal models of maternal high-fat diet (HFD) induced obesity also document persistent changes in offspring behavior and impairments in critical neural circuitry. Animals exposed to maternal obesity and HFD consumption display hyperactivity, impairments in social behavior, increased anxiety-like and depressive-like behaviors, substance addiction, food addiction, and diminished cognition. During development, these offspring are exposed to elevated levels of nutrients (fatty acids, glucose), hormones (leptin, insulin), and inflammatory factors (C-reactive protein, interleukin, and tumor necrosis factor). Such factors appear to permanently change neuroendocrine regulation and brain development in offspring. In addition, inflammation of the offspring brain during gestation impairs the development of neural pathways critical in the regulation of behavior, such as serotoninergic, dopaminergic, and melanocortinergic systems. Dysregulation of these circuits increases the risk of mental health disorders. Given the high rates of obesity in most developed nations, it is critical that the mechanisms by which maternal obesity programs offspring behavior are thoroughly characterized. Such knowledge will be critical in the development of preventative strategies and therapeutic interventions.

Differential Effects of Intrauterine Growth Restriction on the Regional Neurochemical Profile of the Developing Rat Brain

Intrauterine growth restricted (IUGR) infants are at increased risk for neurodevelopmental deficits that suggest the hippocampus and cerebral cortex may be particularly vulnerable. Evaluate regional neurochemical profiles in IUGR and normally grown (NG) 7-day old rat pups using in vivo ¹H magnetic resonance (MR) spectroscopy at 9.4 T. IUGR was induced via bilateral uterine artery ligation at gestational day 19 in pregnant Sprague-Dawley dams. MR spectra were obtained from the cerebral cortex, hippocampus and striatum at P7 in IUGR (N = 12) and NG (N = 13) rats. In the cortex, IUGR resulted in lower concentrations of phosphocreatine, glutathione, taurine, total choline, total creatine (P < 0.01) and [glutamate]/[glutamine] ratio (P < 0.05). Lower taurine concentrations were observed in the hippocampus (P < 0.01) and striatum (P < 0.05). IUGR differentially affects the neurochemical profile of the P7 rat brain regions. Persistent neurochemical changes may lead to cortex-based long-term neurodevelopmental deficits in human IUGR infants.

Associations between self-reported symptoms of prenatal maternal infection and post-traumatic stress disorder in offspring: evidence from a prospective birth cohort study

OBJECTIVE

Consistent evidence has linked a range of prenatal maternal infections with psychotic disorders in later life. However, the potential for this exposure to impact more common disorders requires further investigation.

METHODS

Participants came from the Mater University Study of pregnancy, a longitudinal, pre-birth cohort study which recruited pregnant mothers from a Brisbane hospital between 1981 and 1984. At age 21, 2439 offspring completed the CIDI-Auto. Multivariate logistic regression was used to investigate associations of self-reported symptoms of prenatal infection with a range of DSM-IV anxiety and affective diagnoses, while also testing for gender interactions.

RESULTS

In multivariate analyses, self-reported symptoms of prenatal genital infection predicted Post-traumatic stress disorders (OR=2.38, 95% CI: 1.14, 4.95) and social phobias (OR=1.93, 95% CI: 1.03, 3.61), in addition to evidence for a gender interaction by which males (OR=6.04, 95% CI: 2.00, 18.30) but not females were at greater risk for PTSD. Further analyses among those with PTSD revealed the relationship to be stronger when excluding those not exposed to trauma (OR=3.21, 95% CI: 1.53, 6.72).

LIMITATIONS

We were unable to clinically or serologically verify the presence and the type of prenatal genital infection.

CONCLUSION

This is the first study to show an association between self-reported symptoms of prenatal genital infections and two highly prevalent anxiety disorders among adult offspring. The relationship with PTSD was particularly strong and suggested that the exposure may primarily impact PTSD in males. Further research with the capacity to assess a fuller-range of specific prenatal infections is warranted to evaluate the potential of reducing the prevalence of these disorders.

Fetal programming of schizophrenia: select mechanisms

Mounting evidence indicates that schizophrenia is associated with adverse intrauterine experiences. An adverse or suboptimal fetal environment can cause irreversible changes in brain that can subsequently exert long-lasting effects through resetting a diverse array of biological systems including endocrine, immune and nervous. It is evident from animal and imaging studies that subtle variations in the intrauterine environment can cause recognizable differences in brain structure and cognitive functions in the offspring. A wide variety of environmental factors may play a role in precipitating the emergent developmental dysregulation and the consequent evolution of psychiatric traits in early adulthood by inducing inflammatory, oxidative and nitrosative stress (IO&NS) pathways, mitochondrial dysfunction, apoptosis, and epigenetic dysregulation. However, the precise mechanisms behind such relationships and the specificity of the risk factors for schizophrenia remain exploratory. Considering the paucity of knowledge on fetal programming of schizophrenia, it is timely to consolidate the recent advances in the field and put forward an integrated overview of the mechanisms associated with fetal origin of schizophrenia.

Prenatal maternal immune disruption and sex-dependent risk for psychoses

BACKGROUND

Previous studies suggest that abnormalities in maternal immune activity during pregnancy alter the offspring's brain development and are associated with increased risk for schizophrenia (SCZ) dependent on sex.

METHOD

Using a nested case-control design and prospectively collected prenatal maternal sera from which interleukin (IL)-1β, IL-8, IL-6, tumor necrosis factor (TNF)-α and IL-10 were assayed, we investigated sex-dependent associations between these cytokines and 88 psychotic cases [SCZ = 44; affective psychoses (AP) = 44] and 100 healthy controls from a pregnancy cohort followed for > 40 years. Analyses included sex-stratified non-parametric tests adjusted for multiple comparisons to screen cytokines associated with SCZ risk, followed by deviant subgroup analyses using generalized estimating equation (GEE) models.

RESULTS

There were higher prenatal IL-6 levels among male SCZ than male controls, and lower TNF-α levels among female SCZ than female controls. The results were supported by deviant subgroup analyses with significantly more SCZ males with high IL-6 levels (>highest quartile) compared with controls [odd ratio (OR)75 = 3.33, 95% confidence interval (CI) 1.13-9.82], and greater prevalence of low TNF-α levels (<lowest quartile) among SCZ females compared with their controls (OR25 = 6.30, 95% CI 1.20-33.04) and SCZ males. Higher levels of IL-6 were only found among SCZ compared with AP cases. Lower TNF-α levels (non-significant) also characterized female AP cases versus controls, although the prevalence of the lowest levels was higher in SCZ than AP females (70% v. 40%), with no effect in SCZ or AP males.

CONCLUSIONS

The results underscore the importance of immunologic processes affecting fetal brain development and differential risk for psychoses depending on psychosis subtype and offspring sex.

Maternal prenatal infection, early susceptibility to illness and adult psychotic experiences: a birth cohort study

BACKGROUND

Existing evidence has established that maternal infection during pregnancy and illness during early life are associated with later schizophrenia. No research has examined how the combination of these prenatal and postnatal exposures is linked to an increased risk to later schizophrenia and psychotic disorders.

METHODS

Participants from the Mater University Study of Pregnancy (MUSP), an Australian based, pre-birth cohort study were examined for lifetime DSM-IV positive psychotic experiences at 21 years by a semi-structured interview. Structural equation modelling was used to derive a general factor of psychotic experiences at age 21. Next, we undertook a number of separate analyses to investigate how prenatal infections and infant illness susceptibility are related to positive psychotic experiences in early adulthood, allowing for tests of moderation and mediation between the two risk factors.

RESULTS

After adjustment for important confounders, infant illness susceptibility was found to play a mediating role in the association between prenatal vaginal infection and later psychotic experiences. Whereby, infant illness susceptibility showed a direct association with psychotic experiences, while prenatal vaginal infection indirectly predicted psychotic experiences via infant illness susceptibility.

CONCLUSION

Our findings suggest that illness susceptibility in early infancy may be central to the relationship between prenatal vaginal infection and later psychotic experiences. Further research is needed to establish the mechanisms that link these prenatal and postnatal exposures with psychotic illness in later life.

Neuroprogression in schizophrenia: Pathways underpinning clinical staging and therapeutic corollaries

OBJECTIVE

Whilst dopaminergic dysfunction remains a necessary component involved in the pathogenesis of schizophrenia, our current pharmacological armoury of dopamine antagonists does little to control the negative symptoms of schizophrenia. This suggests other pathological processes must be implicated. This paper aims to elaborate on such theories.

METHODS

Data for this review were sourced from the electronic database PUBMED, and was not limited by language or date of publication.

RESULTS

It has been suggested that multiple 'hits' may be required to unveil the clinical syndrome in susceptible individuals. Such hits potentially first occur in utero, leading to neuronal disruption, epigenetic changes and the establishment of an abnormal inflammatory response. The development of schizophrenia may therefore potentially be viewed as a neuroprogressive response to these early stressors, driven on by changes in tryptophan catabolite (TRYCAT) metabolism, reactive oxygen species handling and N-methyl d-aspartate (NMDA) circuitry. Given the potential for such progression over time, it is prudent to explore the new treatment strategies which may be implemented before such changes become established.

CONCLUSIONS

Outside of the dopaminergic model, the potential pathogenesis of schizophrenia has yet to be fully elucidated, but common themes include neuropil shrinkage, the development of abnormal neuronal circuitry, and a chronic inflammatory state which further disrupts neuronal function. Whilst some early non-dopaminergic treatments show promise, none have yet to be fully studied in appropriately structured randomized controlled trials and they remain little more than potential attractive targets.