Prenatal nutritional deficiency and risk of adult schizophrenia

An enriched environment restored hippocampal cell patterns and enhanced short-term memory in gestational and breastfeeding protein-restricted male offspring

Maternal undernutrition impacts neuron proliferation and differentiation, non-neuron onset, and cell migration, leading to changes in long-term offspring's brain morphology and functionality. This study evaluated the effect of maternal protein intake restriction and enriched environment on the structural hippocampus and behavioral tests in 42-day-old male (low-protein) LP compared to NP (control) offspring. The study supports the selfish brain theory, which suggests that the brain maintains its mass despite significant changes in body weight. The hippocampus cellularity pattern was profoundly altered by reduced neuron numbers in the LP compared to the age-matched NP progeny, as revealed by the isotropic fractionation technique. Detailed data analysis revealed a discrepancy between behavioral tests and reduced hippocampal stem cells and neuron number, accompanied by increased non-neuronal cells, linked to a significant decrease in fear-reflecting behavior. However, the enriched environment (EE) was found to restore the altered neuronal hippocampi cellularity significantly and modify the discrimination ratio, enhancing the ability of both progenies to discriminate between novel and familiar objects in a short time, potentially associated with reversing abnormal hippocampus cell patterns. Immunohistochemistry further validated these findings, showing reduced progenitor cells, neurons, and total cells in mitosis in the LP offspring. At the same time, the enriched environment significantly increased hippocampal cell proliferation, a promising result that could lead to the recovery of neuronal stem cell numbers. The present data underscore the detrimental impact of gestational protein restriction on brain development and highlight EE's potential to restore altered neuronal hippocampi cellularity, offering a hopeful outlook for future research and interventions.

Annual Research Review: Micronutrients and their role in the treatment of paediatric mental illness

The aim of this narrative review is to summarize evidence relating the importance of nutrient intake from diet and supplementation for paediatric mental health. We begin by reviewing several mechanisms by which nutrients maximize brain health, including enabling metabolic reactions to occur, supporting mitochondrial function, reducing inflammation and assisting with detoxification. Circumstances that may contribute to an individual requiring additional nutrients beyond what are available in the diet, such as consumption of nutritionally depleted food, individual differences in biological need, long-term medication use and gut-brain health needs are then reviewed. These factors underpin the importance of tackling deficiencies relative to individual metabolic requirements with a broad spectrum of micronutrients, as opposed to a single nutrient approach, to address personal metabolic needs and/or environmentally induced nutrient depletions. The evidence for treating psychological symptoms with supplementary micronutrients is presented, summarizing research using broad-spectrum micronutrients in the treatment of mental health issues including aggression, autism spectrum disorder, attention-deficit/hyperactivity disorder and emotional dysregulation, often with medium between-group effect sizes compared with placebo, with clinically meaningful changes. The breadth and consistency of the findings highlight the importance of receiving a complete foundation of nutrients to optimize brain health; however, the small number of studies identifies the importance of future work to replicate these preliminary findings. Documented safety in 8-week randomized controlled trials with open-label extensions up to 16 weeks and longer-term follow-up for 1.5-5 years in smaller samples provide reassurance that this treatment approach does not result in serious adverse events. We provide recommendations for future research including consistency in micronutrient interventions, scalable delivery models, effectiveness and implementation studies and the need to investigate these interventions in the prevention and management of less-studied childhood psychiatric conditions.

Impact of feeding age on cognitive impairment in mice with Disrupted-In-Schizophrenia 1 (Disc1) mutation under a high sucrose diet

A combination of genetic predisposition and environmental factors contributes to the development of psychiatric disorders such as schizophrenia, bipolar disorder and major depressive disorder. Previous studies using mouse models suggested that prolonged high sucrose intake during puberty can serve as an environmental risk factor for the onset of psychiatric disorders. However, the impact of both the duration and timing of high sucrose consumption during different developmental stages on pathogenesis remains poorly defined. We therefore investigated the effects of a long-term high sucrose diet on cognitive deficit, a core symptom of psychiatric disorders, using Disrupted-in-Schizophrenia 1 locus-impairment heterozygous mutant (Disc1het) mice as a model for genetic predisposition. First, Disc1het mice and their littermate control (WT) were fed either a high sucrose diet or a control starch diet for nine weeks starting at weaning (postnatal day 24), and tested for cognitive performance in the object location test (OLT) and the novel object recognition test (NORT) (assessing spatial and recognition memory, respectively). Only Disc1het mice on a high sucrose diet displayed deficits in OLT (p < 0.0001), demonstrating impaired hippocampus-dependent spatial memory. This behavioral abnormality was accompanied by a decreased proportion of the high parvalbumin-expressing interneurons (High-PV neurons) in the ventral hippocampus, a cell type that regulates neural activity and a variety of learning and memory processes such as spatial and working memory. We further explored the critical developmental period for high sucrose intake to cause cognitive deficits in adulthood by comparing specific feeding periods during puberty (P24-P65) and post-puberty (P65-P90). Compared to those on a standard chow diet, high sucrose intake caused deficits in spatial memory in both WT and Disc1het mice, with more pronounced effects in Disc1het mice. In particular, Disc1het mice on a sucrose diet during adolescence showed more pronounced cognitive deficit than those fed after adolescence. Our results suggest that adolescence is particularly vulnerable to nutritional environmental risk factors, and that high sucrose consumption may cause hippocampus-dependent memory deficits via decreased High-PV interneuron function when combined with Disc1-related genetic predisposition.

Relevance of diet in schizophrenia: a review focusing on prenatal nutritional deficiency, obesity, oxidative stress and inflammation

BACKGROUND/OBJECTIVES

Schizophrenia is a complex mental disorder influenced by genetic and environmental factors, including dietary habits. Oxidative stress and inflammation play a crucial role in the pathophysiology of schizophrenia. Emerging research suggests that diet may affect schizophrenia through different biological mechanisms beyond oxidative stress and inflammation. In particular, epigenetic changes may alter the expression of genes related to neurodevelopment and neurotransmitter systems, while neuroplasticity plays a crucial role in brain adaptation and resilience to psychiatric disorders.

METHODS

The literature search included the main available databases (Science Direct, PubMed and Google Scholar), considering the English language, and our screening was performed based on several words such as "schizophrenia", "diet", "nutrients", "obesity", "oxidative stress", "inflammation", "antioxidants" and "prenatal nutritional deficiency". The review focused specifically on studies examining the relevance of diet in schizophrenia, as well as prenatal nutritional deficiency, obesity, oxidative stress, and inflammation associated with this disorder.

RESULTS

Following a review of the literature, it was found that nutritional deficiencies, including lack of omega-3 fatty acids, vitamins D, and B, during the prenatal and postnatal periods can have a negative impact on neurodevelopment and increase the risk of schizophrenia. Patients with schizophrenia have imbalances in antioxidant enzymes, such as glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and reduced levels of antioxidants (vitamin E, vitamin C). These biochemical changes lead to an increase in markers of oxidative stress, including malondialdehyde (MDA). In addition, cytokine-mediated inflammation, microglial activation, and intestinal dysbiosis are associated with the onset of schizophrenia and the severity of schizophrenia symptoms. Currently, there is no universally accepted dietary regimen for control. However, various diets and nutritional methods are being researched and applied to alleviate the symptoms of schizophrenia and improve the overall health of patients, including the Mediterranean diet, the ketogenic diet, the gluten-free diet, and the DASH (Dietary Approaches to Stop Hypertension) diet.

CONCLUSION

A healthy diet, rich in anti-inflammatory nutrients and antioxidants, may help manage schizophrenia by reducing oxidative stress, preventing complications, and improving quality of life. Omega-3 fatty acids, vitamin D, and B vitamins are particularly important for brain development and function. In this review, we aim to analyze the literature on the influence of diet on schizophrenia, focusing on the role of prenatal nutritional deficiencies, obesity, oxidative stress, and inflammation.

Perinatal Hypoxia and Immune System Activation in Schizophrenia Pathogenesis: Critical Considerations During COVID-19 Pandemic

Schizophrenia, a severe psychiatric, neurodevelopmental disorder affecting about 0.29-1 % of the global population, is characterized by hallucinations, delusions, cognitive impairments, disorganized thoughts and speech, leading to significant social withdrawal and emotional blunting. During the 1980s, considerations about diseases that result from complex interactions of genetic background and environmental factors started to appear. One of the critical times of vulnerability is the perinatal period. Concerning schizophrenia, obstetric complications that are associated with hypoxia of the fetus or neonate were identified as a risk. Also, maternal infections during pregnancy were linked to schizophrenia by epidemiological, serologic and genetic studies. Research efforts then led to the development of experimental models testing the impact of perinatal hypoxia or maternal immune activation on neurodevelopmental disorders. These perinatal factors are usually studied separately, but given that the models are now validated, it is feasible to investigate both factors together. Inclusion of additional factors, such as metabolic disturbances or chronic stress, may need to be considered also. Understanding the interplay of perinatal factors in schizophrenia's etiology is crucial for developing targeted prevention and therapeutic strategies.

Treating Cognition in Schizophrenia: A Whole Lifespan Perspective

Background/Objectives: Cognitive impairment is a core feature of schizophrenia, affecting attention, memory, and executive function and contributing significantly to the burden of the disorder. These deficits often begin before the onset of psychotic symptoms and persist throughout life, making their treatment essential for improving outcomes and functionality. This work aims to explore the impact of these impairments at different life stages and the interventions that have been developed to mitigate their effects. Methods: This narrative review examined literature searching for different approaches to treat cognitive impairments in schizophrenia across the lifespan. Results: Cognitive alterations appear before psychosis onset, suggesting a window for primary prevention. Then, a period of relative stability with a slight decline gives the period to secondary and eventually tertiary prevention for more than two decades. Finally, another window for tertiary prevention occurs from the third decade of illness until the later stages of the illness, when a progression in cognitive decline could be accelerated in some cases. Cognitive remediation and physical exercise are evidence-based interventions that should be provided to all patients with disabilities. Conclusions: Treating cognition throughout the whole lifespan is crucial for improving functional outcomes. It is necessary to consider the need for personalized, stage-specific strategies to enhance cognitive function and functioning in patients.

Feeding gut microbes to nourish the brain: unravelling the diet-microbiota-gut-brain axis

The prevalence of brain disorders, including stress-related neuropsychiatric disorders and conditions with cognitive dysfunction, is rising. Poor dietary habits contribute substantially to this accelerating trend. Conversely, healthy dietary intake supports mood and cognitive performance. Recently, the communication between the microorganisms within the gastrointestinal tract and the brain along the gut-brain axis has gained prominence as a potential tractable target to modulate brain health. The composition and function of the gut microbiota is robustly influenced by dietary factors to alter gut-brain signalling. To reflect this interconnection between diet, gut microbiota and brain functioning, we propose that a diet-microbiota-gut-brain axis exists that underpins health and well-being. In this Review, we provide a comprehensive overview of the interplay between diet and gut microbiota composition and function and the implications for cognition and emotional functioning. Important diet-induced effects on the gut microbiota for the development, prevention and maintenance of neuropsychiatric disorders are described. The diet-microbiota-gut-brain axis represents an uncharted frontier for brain health diagnostics and therapeutics across the lifespan.

Knockdown of Lhx6 during embryonic development results in neurophysiological alterations and behavioral deficits analogous to schizophrenia in adult rats

A decreased expression of specific interneuron subtypes, containing either the calcium binding protein parvalbumin (PV) or the neurotransmitter somatostatin (SST), are observed in the cortex and hippocampus of both patients with schizophrenia and rodent models used to study the disorder. Moreover, preclinical studies suggest that this loss of inhibitory function is a key pathological mechanism underlying the symptoms of schizophrenia. Interestingly, decreased expression of Lhx6, a key transcriptional regulator specific to the development and migration of PV and SST interneurons, is seen in human postmortem studies and following multiple developmental disruptions used to model schizophrenia preclinically. These results suggest that disruptions in interneuron development in utero may contribute to the pathology of the disorder. To recapitulate decreased Lhx6 expression during development, we used in utero electroporation to introduce an Lhx6 shRNA plasmid and knockdown Lhx6 expression in the brains of rats on gestational day 17. We then examined schizophrenia-like neurophysiological and behavioral alterations in the offspring once they reached adulthood. In utero Lhx6 knockdown resulted in increased ventral tegmental area (VTA) dopamine neuron population activity and a sex-specific increase in locomotor response to a psychotomimetic, consistent with positive symptomology of schizophrenia. However, Lhx6 knockdown had no effect on social interaction or spatial working memory, suggesting behaviors associated with negative and cognitive symptom domains were unaffected. These results suggest that knockdown of Lhx6 during development results in neurophysiological and behavioral alterations consistent with the positive symptom domain of schizophrenia in adult rats.

Health of singleton neonates in Switzerland through time and crises: a cross-sectional study at the population level, 2007-2022

BACKGROUND

Being exposed to crises during pregnancy can affect maternal health through stress exposure, which can in return impact neonatal health. We investigated temporal trends in neonatal outcomes in Switzerland between 2007 and 2022 and their variations depending on exposure to the economic crisis of 2008, the flu pandemic of 2009, heatwaves (2015 and 2018) and the COVID-19 pandemic.

METHODS

Using individual cross-sectional data encompassing all births occurring in Switzerland at the monthly level (2007-2022), we analysed changes in birth weight and in the rates of preterm birth (PTB) and stillbirth through time with generalized additive models. We assessed whether the intensity or length of crisis exposure was associated with variations in these outcomes. Furthermore, we explored effects of exposure depending on trimesters of pregnancy.

RESULTS

Over 1.2 million singleton births were included in our analyses. While birth weight and the rate of stillbirth have remained stable since 2007, the rate of PTB has declined by one percentage point. Exposure to the crises led to different results, but effect sizes were overall small. Exposure to COVID-19, irrespective of the pregnancy trimester, was associated with a higher birth weight (+12 grams [95% confidence interval (CI) 5.5 to 17.9 grams]). Being exposed to COVID-19 during the last trimester was associated with an increased risk of stillbirth (odds ratio 1.24 [95%CI 1.02 to 1.50]). Exposure to the 2008 economic crisis during pregnancy was not associated with any changes in neonatal health outcomes, while heatwave effect was difficult to interpret.

CONCLUSION

Overall, maternal and neonatal health demonstrated resilience to the economic crisis and to the COVID-19 pandemic in a high-income country like Switzerland. However, the effect of exposure to the COVID-19 pandemic is dual, and the negative impact of maternal infection on pregnancy is well-documented. Stress exposure and economic constraint may also have had adverse effects among the most vulnerable subgroups of Switzerland. To investigate better the impact of heatwave exposure on neonatal health, weekly or daily-level data is needed, instead of monthly-level data.

Evaluating different models of maternal stress on stress-responsive systems in prepubertal mice

Introduction

Maternal adversity during pregnancy influences neurodevelopment in human and model animal offspring. Adversity can result from stressors coming from many different directions ranging from environmental to nutritional and physiological to immune (e.g., infection). Most stressors result in fetal overexposure to glucocorticoids that have been directly linked to long- and short-term negative impacts on neurological health of offspring. Neuropsychiatric diseases postulated to have fetal origins are diverse and include such things cardiovascular disease, obesity, affective disorders, and metabolic and immune disorders.

Methods

The experiments in the current study compare 3 stressors: prenatal exposure to dexamethasone (DEX), maternal high fat diet (HFD), and maternal caloric restriction (CR). Offspring of mothers with these treatments were examined prepubertally to evaluate stress responsiveness and stress-related behaviors in in male and female mice.

Results

Prenatal exposure to synthetic glucocorticoid, DEX, resulted in decreased neonatal body weights, reduced social interaction behavior, and hypoactive stress response offspring exposed to maternal DEX. Maternal CR resulted in decreased body weights and social interaction behavior in males and females and increased anxiety-like behavior and acute stress response only in males. HFD resulted in altered body weight gain in both sex offspring with decreased anxiety-like behavior in a female-biased manner.

Discussion

The idea that glucocorticoid responses to different stressors might serve as a common stimulus across stress paradigms is insufficient, given that different modes of prenatal stress produced differential effects. Opposite nutritional stressors produced similar outcomes for anxiety-like behavior in both sexes, social-like behavior in females, and a hyperactive adrenal stress response in males. One common theme among the three models of maternal stress (DEX, CR, and HFD) was consistent data showing their role in activating the maternal and fetal immune response. By tuning in on the more immediate immunological aspect on the developing fetus (e.g., hormones, cytokines), additional studies may tease out more direct outcomes of maternal stress in rodents and increase their translational value to human studies.

Women with Schizophrenia Have Difficulty Maintaining Healthy Diets for Themselves and Their Children: A Narrative Review

Severe psychiatric disorders such as schizophrenia are inevitably linked to unemployment, meagre per capita income, and residence in disadvantaged, poorly resourced neighbourhoods. This means difficult access to healthy food and is particularly problematic for pregnant women and mothers with children to feed. The necessity of taking antipsychotic drugs is an additional barrier to healthy eating because these drugs are associated with serious cognitive, psychological, behavioural, and metabolic sequelae. Being ill with psychosis makes it extremely difficult to maintain a healthy diet; nutritional deficiencies result, as do medical complications. The results of present literature review confirm the gravity of the problem and suggest a number of potentially useful clinical interventions.

Causal link between thyroid function and schizophrenia: a two-sample Mendelian randomization study

Schizophrenia is a chronic psychiatric disorder with inconsistent behavioral and cognitive abnormalities with profound effects on the individual and the society. Individuals with schizophrenia have altered thyroid function, but results from observational studies are conflicting. To date, it remains unclear whether and in which direction there is a causal relationship between thyroid function and schizophrenia. To investigate causal paths, a bidirectional two-sample Mendelian randomization (MR) study was conducted using summary statistics from genome-wide association studies including up to 330,132 Europeans. Thyroid function was described by the normal-range thyroid-stimulating hormone (TSH) and free thyroxine levels as well as an increased and decreased TSH status. The iterative radial inverse-variance weighted approach with modified second order weights was used as the main method. Based on a discovery and replication sample for schizophrenia, pooled effect estimates were derived using a fixed-effect meta-analysis. Robustness of results was assessed using both a range of pleiotropy robust methods and a network analysis that clustered genetic instruments potentially responsible for horizontal pleiotropy. Genetic liability for hypothyroidism was inversely associated with schizophrenia ([Formula: see text]; 95% CI: (-0.10; -0.02); [Formula: see text]). No notable associations were observed between other thyroid parameters and schizophrenia. Furthermore, no associations could be detected in the reverse direction. Our results suggest that an elevated level of TSH reduce the risk for schizophrenia. The role of thyroid function and the hypothalamic-pituitary-thyroid axis in the development of schizophrenia should be subject of further research.

Viral Infections and Schizophrenia: A Comprehensive Review

Schizophrenia is a complex mental disorder with multiple genetic and environmental factors contributing to its pathogenesis. Viral infections have been suggested to be one of the environmental factors associated with the development of this disorder. We comprehensively review all relevant published literature focusing on the relationship between schizophrenia and various viral infections, such as influenza virus, herpes virus 1 and 2 (HSV-1 and HSV-2), cytomegalovirus (CMV), Epstein-Barr virus (EBV), retrovirus, coronavirus, and Borna virus. These viruses may interfere with the normal maturation of the brain directly or through immune-induced mediators, such as cytokines, leading to the onset of schizophrenia. Changes in the expression of critical genes and elevated levels of inflammatory cytokines have been linked to virally-induced infections and relevant immune activities in schizophrenia. Future research is necessary to understand this relationship better and provide insight into the molecular mechanisms underlying the pathophysiology of schizophrenia.

Interpregnancy interval and the risk of oppositional defiant disorder in offspring

The study aimed to investigate the association between interpregnancy interval (IPI) and parent-reported oppositional defiant disorder (ODD) in offspring at 7 and 10 years of age. We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC), an ongoing population-based longitudinal study based in Bristol, United Kingdom (UK). Data included in the analysis consisted of more than 3200 mothers and their singleton children. The association between IPI and ODD was determined using a series of log-binomial regression analyses. We found that children of mothers with short IPI (<6 months) were 2.4 times as likely to have a diagnosis of ODD at 7 and 10 years compared to mothers with IPI of 18-23 months (RR = 2.45; 95%CI: 1.24-4.81 and RR = 2.40; 95% CI: 1.08-5.33), respectively. We found no evidence of associations between other IPI categories and risk of ODD in offspring in both age groups. Adjustment for a wide range of confounders, including maternal mental health, and comorbid ADHD did not alter the findings. This study suggests that the risk of ODD is higher among children born following short IPI (<6 months). Future large prospective studies are needed to elucidate the mechanisms explaining this association.

Systematic review and meta-analysis: Season of birth and schizophrenia risk

OBJECTIVE

Winter birth has been hypothesized to be associated with increased schizophrenia risk for nearly a century. Major hypotheses regarding the potential etiological risk factors for schizophrenia such as vitamin D deficiency and virus exposure in utero are predicated based on the observation that risk of schizophrenia is higher in children born in winter months.

METHODS

We conducted a systematic review and meta-analysis to examine the association between season and month of birth and risk of schizophrenia. We further investigated this relationship stratified by hemisphere.

RESULTS

Forty-three studies spanning 30 countries and territories and 440,039 individuals with schizophrenia were included in this meta-analysis. Winter births were associated with a small but statistically significant increased risk of schizophrenia (OR 1.05, 95 % CI 1.03-1.07, p < 0.0001) and summer births were associated with a small but statistically significant decreased risk of schizophrenia (OR 0.96, 95 % CI 0.94-0.98, p = 0.0001). Stratified subgroup analysis demonstrated no significant difference between hemispheres in the risk of schizophrenia for either winter or summer births.

CONCLUSIONS

Analysis using birth month data demonstrated a clear seasonal trend towards increased risk of schizophrenia being associated with winter birth months and decreased risk of schizophrenia in summer-to-fall months in the Northern but not Southern Hemisphere. These data suggest a small-but-substantial increased risk of schizophrenia in winter birth month. Further research needs to examine potential etiologic causes for this association.

Understanding translational research in schizophrenia: A novel insight into animal models

Schizophrenia affects millions of people worldwide and is a major challenge for the scientific community. Like most psychotic diseases, it is also considered a complicated mental disorder caused by an imbalance in neurotransmitters. Due to the complexity of neuropathology, it is always a complicated disorder. The lack of proper understanding of the pathophysiology makes the disorder unmanageable in clinical settings. However, due to recent advances in animal models, we hope we can have better therapeutic approaches with more success in clinical settings. Dopamine, glutamate, GABA, and serotonin are the neurotransmitters involved in the pathophysiology of schizophrenia. Various animal models have been put forward based on these neurotransmitters, including pharmacological, neurodevelopmental, and genetic models. Polymorphism of genes such as dysbindin, DICS1, and NRG1 has also been reported in schizophrenia. Hypothesis based on dopamine, glutamate, and serotonin are considered successful models of schizophrenia on which drug therapies have been designed to date. New targets like the orexin system, muscarinic and nicotinic receptors, and cannabinoid receptors have been approached to alleviate the negative and cognitive symptoms. The non-pharmacological models like the post-weaning social isolation model (maternal deprivation), the isolation rearing model etc. have been also developed to mimic the symptoms of schizophrenia and to create and test new approaches of drug therapy which is a breakthrough at present in psychiatric disorders. Different behavioral tests have been evaluated in these specific models. This review will highlight the currently available animal models and behavioral tests in psychic disorders concerning schizophrenia.

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 synergistic effects of short inter-pregnancy interval and micronutrients deficiency on third-trimester depression

Objective

To explore the effect of inter-pregnancy interval (IPI) and micronutrients on depression in the third trimester of pregnancy.

Materials and methods

A total of 5,951 eligible pregnant women were included in this single-center retrospective cohort study. Variables with potential effects on third-trimester depression were collected. These variables included: maternal factors [age, pregnancy interval, body mass index (BMI), BMI change, gravidity, native place, education, smoking, and alcohol consumption], previous delivery outcomes [preterm birth, preeclampsia, intrahepatic cholestasis of pregnancy (ICP), gestational diabetes mellitus (GDM), fetal growth restriction (FGR), and delivery mode], and micronutrients in early pregnancy (folic acid, 25-hydroxy vitamin D, vitamin B12, calcium, and ferritin). Univariate and multivariate analyses were used to screen the factors affecting the occurrence of depression. Based on these factors, the nomogram model was established. At the same time, the interaction between IPI and micronutrients was verified.

Results

The incidence of depression in the third trimester of pregnancy was 4.3%. Univariate and multivariate analysis showed that there were five independent risk factors for third-trimester depression: gravidity, previous cesarean section delivery, folic acid, and vitamin D levels in early pregnancy and IPI. According to the multivariate logistic regression analysis, the prediction model and nomogram were established. The prediction cut-offs of the corresponding factors were calculated according to the Youden index. Finally, the synergistic effect of short IPI and micronutrient deficiency was verified.

Conclusion

There is a synergistic effect between short IPI and micronutrient deficiency in early pregnancy, which can aggravate the occurrence of depression in late pregnancy.

Prenatal infection and schizophrenia: A decade of further progress

Epidemiologic studies have provided evidence that prenatal exposure to maternal infection is associated with an increased risk of developing schizophrenia in the offspring. Research over the past decade has added further to our understanding of the role of prenatal infection in schizophrenia risk. These investigations include several well-powered designs, and like some earlier studies, measured maternal antibodies to specific infectious agents in stored serum samples and large registers to identify clinically diagnosed infections during pregnancy. Convergent findings from antibody studies suggest that prenatal maternal infection with Toxoplasma gondii is associated with increased schizophrenia risk in the offspring, while associations with HSV-2 infection are likely attributable to confounding. Maternal influenza infection remains a viable candidate for schizophrenia, based on an early serological study, though there has been only one attempt to replicate this finding, with a differing methodology. A prior association between maternal serologically confirmed cytomegalovirus infections require further study. Clinically diagnosed maternal infection, particularly bacterial infection, also appears to be associated with increased risk of offspring schizophrenia, and heterogeneity in these findings is likely due to methodological differences between studies. Further clarification may be provided by future studies that address the timing, type, and clinical features of infections. Important insight may be gained by examining the long-term offspring outcomes in emerging epidemics such as Zika virus and COVID-19, and by investigating the interaction between exposure to prenatal infection and other risk or protective factors.

ABCB9 polymorphism rs61955196 is associated with schizophrenia in a Chinese Han population

BACKGROUND

Schizophrenia (SCZ) is a complex disease which can be affected by both genetic and environmental factors. Prenatal famine exposure may cause changes in DNA methylation levels of genes. Meanwhile, maternal nutrition during pregnancy is a pivotal environmental factor in the development of SCZ. DNA methylation may be an intermediate factor mediating exposure to famine during pregnancy and SCZ, and DNA methylation quantitative trait loci might serve as a promising tool for linking SCZ and prenatal famine.

AIM

To analyze the association between prenatal famine exposure and SCZ risk in Northeast Han Chinese through analysis of DNA methylation related loci.

METHODS

A total of 954 Han Chinese from Northeast China were recruited, including 443 patients with SCZ and 511 healthy controls. The participants were further divided into famine (born in 1960-1962) and non-famine (born in 1963-1965) groups to investigate the effect of prenatal famine exposure. Four single-nucleotide polymorphisms (SNPs) selected according to the relevant literature were genotyped, namely, rs11917047 in PTPRG, rs2239681 in IGF2, rs3842756 in INSIGF, and rs61955196 in ABCB9. DNA were extracted from peripheral blood samples, and the genotypes of these SNP loci were detected using the improved Multiple Ligase Detection Reaction multiple SNP typing technique. The associations of the DNA methylation related SNPs with SCZ risk and prenatal famine, and their interactions were analyzed using logistic regression analysis and generalized multifactor dimensionality reduction (GMDR) software.

RESULTS

Based on the sequencing data, genotype distributions and allele frequencies of the four selected SNPs were determined. All genotype frequencies of the four SNPs in the healthy control group were tested for deviation from Hardy-Weinberg equilibrium (P > 0.05). Logistic regression analysis showed that rs61955196 was significantly associated with SCZ risk in the log-additive model [odds ratio (OR): 1.22; 95% confidence interval (CI): 1.01-1.48; P = 0.040]. We also found that the rs61955196 allele was related with an enhanced risk of SCZ (G>C, OR: 1.22; 95%CI: 1.01-1.47; P = 0.042). However, no associations were observed between rs11917047, rs2239681, or rs3842756 and SCZ risk. Under the optimal genetic model, no significant association of famine with the four SNPs was seen. Though the gene–gene interactions between rs2239681 and rs61955196 were found in GMDR analysis, none of the gene-gene interactions and gene-famine interactions were associated with the risk of SCZ.

CONCLUSION

Our study suggested that rs61955196 in ABCB9 is associated with SCZ susceptibility in Northeast Han Chinese, providing insight into genetic effects on SCZ.

Prenatal methotrexate injection increases behaviors possibly associated with depression and/or autism in rat offspring; A new animal model for mental disorder, based on folate metabolism deficit during pregnancy

Background

Deficiency of folate, an essential vitamin for DNA synthesis and methylation, is reported as a risk factor for mental disorders. Considering a possibility that folate metabolism deficit during pregnancy may disturb CNS development and increase mental disorders in offspring, we treated pregnant rats with methotrexate (MTX), an inhibitor of folate metabolic enzyme, and evaluated offspring behaviors.

Methods

Saline or MTX was intraperitoneally administered to female SD rats on gestational day 17. Offspring behaviors were evaluated during approximately 6–9 weeks old; prepulse inhibition (PPI), social interaction (SI), locomotor activity (LA), and forced swimming test (FST) for evaluation of schizophrenia, depression, and autism related behaviors; the elevated plus maze (EPM) and the light–dark box (LD) test for evaluation of anxiety.

Results

Compared to saline‐treated group, MTX‐treated group showed decrease of SI and increase of immobility time in FST. In addition, increases of time spent in the light box and shuttling between the light–dark boxes were observed in LD test. On the other hand, no changes were confirmed in EPM, LA, and PPI.

Conclusion

Decrease of SI and increase of immobility time in FST may suggest association of this animal model with depression and/or autism. Increase of time spent in the light box and shuttling between the light–dark boxes may indicate changes in anxiety or cognitive level to environment, or repetitive behaviors in autism. Although further studies are warranted to characterize this animal model, at least we can say that prenatal MTX exposure, possibly causing folate metabolism deficit, affects offspring behaviors.

Early magnetic resonance imaging biomarkers of schizophrenia spectrum disorders: Toward a fetal imaging perspective

There is mounting evidence to implicate the intrauterine environment as the initial pathogenic stage for neuropsychiatric disease. Recent developments in magnetic resonance imaging technology are making a multimodal analysis of the fetal central nervous system a reality, allowing analysis of structural and functional parameters. Exposures to a range of pertinent risk factors whether preconception or in utero can now be indexed using imaging techniques within the fetus' physiological environment. This approach may determine the first "hit" required for diseases that do not become clinically manifest until adulthood, and which only have subtle clinical markers during childhood and adolescence. A robust characterization of a "multi-hit" hypothesis may necessitate a longitudinal birth cohort; within this investigative paradigm, the full range of genetic and environmental risk factors can be assessed for their impact on the early developing brain. This will lay the foundation for the identification of novel biomarkers and the ability to devise methods for early risk stratification and disease prevention. However, these early markers must be followed over time: first, to account for neural plasticity, and second, to assess the effects of postnatal exposures that continue to drive the individual toward disease. We explore these issues using the schizophrenia spectrum disorders as an illustrative paradigm. However, given the potential richness of fetal magnetic resonance imaging, and the likely overlap of biomarkers, these concepts may extend to a range of neuropsychiatric conditions.

Maternal body mass index in pregnancy and mental disorders in adult offspring: a record linkage study in Aberdeen, Scotland

Maternal obesity in pregnancy predicts offspring psychopathology risk in childhood but it remains unclear whether maternal obesity or underweight associate with adult offspring mental disorders. We examined longitudinally whether maternal body mass index (BMI) in pregnancy predicted mental disorders in her offspring and whether the associations differed by offspring birth year among 68,571 mother–child dyads of Aberdeen Maternity and Neonatal Databank, Scotland. The offspring were born 1950–1999. Maternal BMI was measured at a mean 15.7 gestational weeks and classified into underweight, normal weight, overweight, moderate obesity and severe obesity. Mental disorders were identified from nationwide registers carrying diagnoses of all hospitalizations and deaths in Scotland in 1996–2017. We found that maternal BMI in pregnancy was associated with offspring mental disorders in a time-dependent manner: In offspring born 1950–1974, maternal underweight predicted an increased hazard of mental disorders [Hazard Ratio (HR) = 1.74; 95% Confidence Interval (CI) = 1.01–3.00)]. In offspring born 1975–1999, maternal severe obesity predicted increased hazards of any mental (HR 1.60; 95% CI 1.08–2.38) substance use (HR 1.91; 95% CI 1.03–3.57) and schizophrenia spectrum (HR 2.80; 95% CI 1.40–5.63) disorders. Our findings of time-specific associations between maternal prenatal BMI and adult offspring mental disorders may carry important public health implications by underlining possible lifelong effects of maternal BMI on offspring psychopathology.

From Womb to Neighborhood: A Racial Analysis of Social Determinants of Psychosis in the United States

The authors examine U.S.-based evidence that connects characteristics of the social environment with outcomes across the psychosis continuum, from psychotic experiences to schizophrenia. The notion that inequitable social and economic systems of society significantly influence psychosis risk through proxies, such as racial minority and immigrant statuses, has been studied more extensively in European countries. While there are existing international reviews of social determinants of psychosis, none to the authors' knowledge focus on factors in the U.S. context specifically-an omission that leaves domestic treatment development and prevention efforts incomplete and underinformed. In this review, the authors first describe how a legacy of structural racism in the United States has shaped the social gradient, highlighting consequential racial inequities in environmental conditions. The authors offer a hypothesized model linking structural racism with psychosis risk through interwoven intermediary factors based on existing theoretical models and a review of the literature. Neighborhood factors, cumulative trauma and stress, and prenatal and perinatal complications were three key areas selected for review because they reflect social and environmental conditions that may affect psychosis risk through a common pathway shaped by structural racism. The authors describe evidence showing that Black and Latino people in the United States suffer disproportionately from risk factors within these three key areas, in large part as a result of racial discrimination and social disadvantage. This broad focus on individual and community factors is intended to provide a consolidated space to review this growing body of research and to guide continued inquiries into social determinants of psychosis in U.S. contexts.

The Impact of Stress Within and Across Generations: Neuroscientific and Epigenetic Considerations

The impact of stress and trauma on biological systems in humans can be substantial. They can result in epigenetic changes, accelerated brain development and sexual maturation, and predisposition to psychopathology. Such modifications may be accompanied by behavioral, emotional, and cognitive overtones during one's lifetime. Exposure during sensitive periods of neural development may lead to long-lasting effects that may not be affected by subsequent environmental interventions. The cumulative effects of life stressors in an individual may affect offspring's methylome makeup and epigenetic clocks, neurohormonal modulation and stress reactivity, and physiological and reproductive development. While offspring may suffer deleterious effects from parental stress and their own early-life adversity, these factors may also confer traits that prove beneficial and enhance fitness to their own environment. This article synthesizes the data on how stress shapes biological and behavioral dimensions, drawing from preclinical and human models. Advances in this field of knowledge should potentially allow for an improved understanding of how interventions may be increasingly tailored according to individual biomarkers and developmental history.

Being Born in Winter-Spring and at Around the Time of an Influenza Pandemic Are Risk Factors for the Development of Schizophrenia: The Apna Study in Navarre, Spain

Background: We analyzed the relationship between the prevalence of schizophrenia and the season of birth and gestation during a period of an influenza pandemic. Methods: Cross-sectional analysis of a prospective population-based cohort of 470,942 adults. We fitted multivariant logistic regression models to determine whether the season of birth and birth in an influenza-pandemic year (1957, 1968, 1977) was associated with schizophrenia. Results: 2077 subjects had been diagnosed with schizophrenia. Logistic regression identified a significantly greater prevalence of schizophrenia in men than in women (OR = 1.516, CI 95% = 1.388–1.665); in those born in the winter or spring than in those born in the summer or autumn (OR = 1.112, CI 95% = 1.020–1.212); and in those born in a period of an influenza pandemic (OR = 1.335, CI 95% = 1.199–1.486). The increase in risk was also significant when each influenza pandemic year was analyzed separately. However, neither month of birth nor season of birth, when each of the four were studied individually, were associated with a statistically significant increase in that risk. Conclusions: The winter–spring period and the influenza pandemics are independent risk factors for developing schizophrenia. This study contradicts many previous studies and thus revitalizes a locked debate in understanding the neurodevelopmental hypothesis of this disorder.

Neurological consequences of neurovascular unit and brain vasculature damages: potential risks for pregnancy infections and COVID-19-babies

Intragravidic and perinatal infections, acting through either direct viral effect or immune-mediated responses, are recognized causes of liability for neurodevelopmental disorders in the progeny. The large amounts of epidemiological data and the wealth of information deriving from animal models of gestational infections have contributed to delineate, in the last years, possible underpinning mechanisms for this phenomenon, including defects in neuronal migration, impaired spine and synaptic development, and altered activation of microglia. Recently, dysfunctions of the neurovascular unit and anomalies of the brain vasculature have unexpectedly emerged as potential causes at the origin of behavioral abnormalities and psychiatric disorders consequent to prenatal and perinatal infections. This review aims to discuss the up-to-date literature evidence pointing to the neurovascular unit and brain vasculature damages as the etiological mechanisms in neurodevelopmental syndromes. We focus on the inflammatory events consequent to intragravidic viral infections as well as on the direct viral effects as the potential primary triggers. These authors hope that a timely review of the literature will help to envision promising research directions, also relevant for the present and future COVID-19 longitudinal studies.

Maternal Spirulina supplementation during pregnancy and lactation partially prevents oxidative stress, glial activation and neuronal damage in protein malnourished F1 progeny

Protein malnutrition (PMN) is a global health issue but most prevalent in Africa and Asia. It exerts detrimental effect on structural and physiological aspects of hippocampal circuitry. Despite accumulating evidence for PMN induced changes in nervous system, relatively very little is known about how maternal nutritional supplementation during malnutrition affects glial cells and neurons. Herein, we aimed to investigate the effects of maternal Spirulina supplementation against PMN induced oxidative stress, reactive gliosis and neuronal damage in hippocampus of F1 progeny. Three months old healthy Sprague Dawley females (n = 24) were shifted to normoprotein (NC; 20% protein) and low protein (LP; 8% protein) diets 15 days before conception. The NC and LP group females were subdivided into two groups according to Spirulina supplementation (400 mg/kg/b.wt. orally throughout gestation and lactation period): normal control with Spirulina (NC SPI) and low protein with Spirulina supplemented group (LP SPI). F1 progeny born were used in present study. Thus, building on earlier results of ameliorated neurobehavioral and cognitive abilities in Spirulina supplemented protein deprived rats, the present study incorporates neurochemical and morphometric analysis of glial cells and neurons and revealed that maternal Spirulina consumption partially prevented the PMN associated neuropathological alterations in terms of attenuated oxidative brain damage, reduced reactive gliosis and apoptotic cell population, improved dendritic branch complexity with few damaged neurons and enhanced mushroom shaped spine density. The results suggest that cellular changes in hippocampus after PMN are partially restored after maternal Spirulina supplementation and one could envision intervention approaches using Spirulina against malnutrition.

Environmental epigenetics of sex differences in the brain

Experiences throughout the life course lead to unique phenotypes even among those with the same genotype. Genotype sets the substrate on which physiologic processes, which communicate with the brain, mediate the effects of life experiences via epigenetics. Epigenetics modify the expression of genes in the brain and body in response to circulating hormones and other mediators, which are activated to facilitate survival responses through a process called allostasis. Epigenetic signatures can even be inherited, resulting in transgenerational effects. This chapter addresses epigenetics in the context of sex differences, discussing the intersection between genetics and gonadal hormones and their effect in the brain at discrete developmental periods.

Stem Cells for Improving the Treatment of Neurodevelopmental Disorders

Treatment options for neurodevelopmental disorders such as schizophrenia and autism are currently limited. Antipsychotics used to treat schizophrenia are not effective for all patients, do not target all symptoms of the disease, and have serious adverse side effects. There are currently no FDA-approved drugs to treat the core symptoms of autism. In an effort to develop new and more effective treatment strategies, stem cell technologies have been used to reprogram adult somatic cells into induced pluripotent stem cells, which can be differentiated into neuronal cells and even three-dimensional brain organoids. This new technology has the potential to elucidate the complex mechanisms that underlie neurodevelopmental disorders, offer more relevant platforms for drug discovery and personalized medicine, and may even be used to treat the disease.

Fetal growth restriction mice are more likely to exhibit depression-like behaviors due to stress-induced loss of dopaminergic neurons in the VTA

Fetal growth restriction (FGR) is a severe perinatal complication that can increase risk for mental illness. To investigate the mechanism by which FGR mice develop mental illness in adulthood, we established the FGR mouse model and the FGR mice did not display obvious depression-like behaviors, but after environmental stress exposure, FGR mice were more likely to exhibit depression-like behaviors than control mice. Moreover, FGR mice had significantly fewer dopaminergic neurons in the ventral tegmental area but no difference in serotoninergic neurons in the dorsal raphe. RNA-seq analysis showed that the downregulated genes in the midbrain of FGR mice were associated with many mental diseases and were especially involved in the regulation of NMDA-selective glutamate receptor (NMDAR) activity. Furthermore, the NMDAR antagonist memantine can relieve the stress-induced depression-like behaviors of FGR mice. In summary, our findings provide a theoretical basis for future research and treatment of FGR-related depression.

Metabolomic and transcriptomic signatures of prenatal excessive methionine support nature rather than nurture in schizophrenia pathogenesis

The imbalance of prenatal micronutrients may perturb one-carbon (C1) metabolism and increase the risk for neuropsychiatric disorders. Prenatal excessive methionine (MET) produces in mice behavioral phenotypes reminiscent of human schizophrenia. Whether in-utero programming or early life caregiving mediate these effects is, however, unknown. Here, we show that the behavioral deficits of MET are independent of the early life mother-infant interaction. We also show that MET produces in early life profound changes in the brain C1 pathway components as well as glutamate transmission, mitochondrial function, and lipid metabolism. Bioinformatics analysis integrating metabolomics and transcriptomic data reveal dysregulations of glutamate transmission and lipid metabolism, and identify perturbed pathways of methylation and redox reactions. Our transcriptomics Linkage analysis of MET mice and schizophrenia subjects reveals master genes involved in inflammation and myelination. Finally, we identify potential metabolites as early biomarkers for neurodevelopmental defects and suggest therapeutic targets for schizophrenia.

Chen, Alhassen et al. show that schizophrenia-like behavioral deficits induced by excessive prenatal methionine administration are due to in-uterus aberrations rather than through early life mother-infant interaction in mice. This study identifies the brain metabolites and transcriptomic signatures, which potentially serve as early biomarkers for schizophrenia-like behaviors.

Developmental alterations in the transcriptome of three distinct rodent models of schizophrenia

Schizophrenia is a debilitating disorder affecting just under 1% of the population. While the symptoms of this disorder do not appear until late adolescence, pathological alterations likely occur earlier, during development in utero. While there is an increasing literature examining transcriptome alterations in patients, it is not possible to examine the changes in gene expression that occur during development in humans that will develop schizophrenia. Here we utilize three distinct rodent developmental disruption models of schizophrenia to examine potential overlapping alterations in the transcriptome, with a specific focus on markers of interneuron development. Specifically, we administered either methylazoxymethanol acetate (MAM), Polyinosinic:polycytidylic acid (Poly I:C), or chronic protein malnutrition, on GD 17 and examined mRNA expression in the developing hippocampus of the offspring 18 hours later. Here, we report alterations in gene expression that may contribute to the pathophysiology of schizophrenia, including significant alterations in interneuron development and ribosome function.

Vitamin D deficiency and Schizophrenia in Adults: A Systematic Review and Meta-analysis of Observational Studies

Schizophrenia is a heterogeneous disorder in which there is an interaction between genetic and environmental factors. Accumulating data show that there may be an association between vitamin D deficiency and schizophrenia. We conducted an updated meta-analysis to investigate the relationship between schizophrenia and blood vitamin D level. All published observational articles have been searched from five databases until September 2019. In total, 36 articles with a total of 12528 participants were included in this study. Patients with schizophrenia have significantly lower levels of vitamin D than controls. The subgroup analyses based on study design, hospitalization status, quality score, type of biomarker [25-hydroxyvitamin D or 25-hydroxyvitamin D₃], and the country did not explain between-study heterogeneity; however, meta-regression on match factors indicted that match of BMI could account for some degree of heterogeneity. No significant differences in publication bias were observed. Also, subjects with schizophrenia were more likely to have vitamin D deficiency or insufficiency compared to controls. In conclusion, our analyses are consistent with the hypothesis that vitamin D deficiency is associated with schizophrenia. More well-designed randomized control trials are needed to determine whether this association is causal.

Genetic regulatory subnetworks and key regulating genes in rat hippocampus perturbed by prenatal malnutrition: implications for major brain disorders

OBJECTIVE

Many population studies have shown that maternal prenatal nutrition deficiency may increase the risk of neurodevelopmental disorders in their offspring, but its potential transcriptomic effects on brain development are not clear. We aimed to investigate the transcriptional regulatory interactions between genes in particular pathways responding to the prenatal nutritional deficiency and to explore their effects on neurodevelopment and related disorders.

RESULTS

We identified three modules in rat hippocampus responding to maternal prenatal nutritional deficiency and found 15 key genes (Hmgn1, Ssbp1, LOC684988, Rpl23, Gga1, Rhobtb2, Dhcr24, Atg9a, Dlgap3, Grm5, Scn2b, Furin, Sh3kbp1, Ubqln1, and Unc13a) related to the rat hippocampus developmental dysregulation, of which Hmgn1, Rhobtb2 and Unc13a related to autism, and Dlgap3, Grm5, Furin and Ubqln1 are related to Alzheimer's disease, and schizophrenia. Transcriptional alterations of the hub genes were confirmed except for Atg9a. Additionally, through modeling miRNA-mRNA-transcription factor interactions for the hub genes, we confirmed a transcription factor, Cebpa, is essential to regulate the expression of Rhobtb2. We did not find singificent singals in the prefrontal cortex responding to maternal prenatal nutritional deficiency.

CONCLUSION

These findings demonstrated that these genes with the three modules in rat hippocampus involved in synaptic development, neuronal projection, cognitive function, and learning function are significantly enriched hippocampal CA1 pyramidal neurons and suggest that three genetic regulatory subnetworks and thirteen key regulating genes in rat hippocampus perturbed by a prenatal nutrition deficiency. These genes and related subnetworks may be prenatally involved in the etiologies of major brain disorders, including Alzheimer's disease, autism, and schizophrenia.

METHODS

We compared the transcriptomic differences in the hippocampus and prefrontal cortex between 10 rats with prenatal nutritional deficiency and 10 rats with prenatal normal chow feeding by differential analysis and co-expression network analysis. A network-driven integrative analysis with microRNAs and transcription factors was performed to define significant modules and hub genes responding to prenatal nutritional deficiency. Meanwhile, the module preservation test was conducted between the hippocampus and prefrontal cortex. Expression levels of the hub genes were further validated with a quantitative real-time polymerase chain reaction based on additional 40 pairs of rats.

Prenatal alcohol exposure and developmental programming of mental illness

It is well established that high-dose alcohol consumption during pregnancy increases the risk for a plethora of adverse offspring outcomes. These include neurodevelopmental, cognitive and social deficits, as well as psychiatric illnesses, such as depression and anxiety. However, much less evidence is available on the effects of low- and early-dose alcohol exposure on mental health outcomes, regardless of the accumulating evidence that mental health outcomes should be considered in the context of the Developmental Origins of Health and Disease hypothesis. This review will discuss the evidence that indicates low-dose and early prenatal alcohol exposure can increase the risk of mental illness in offspring and discuss the mechanistic pathways that may be involved.

Nutrient restriction causes reversible G2 arrest in Xenopus neural progenitors

Nutrient status affects brain development; however, the effects of nutrient availability on neural progenitor cell proliferation in vivo are poorly understood. Without food, Xenopus laevis tadpoles enter a period of stasis during which neural progenitor proliferation is drastically reduced, but resumes when food becomes available. Here, we investigate how neural progenitors halt cell division in response to nutrient restriction and subsequently re-enter the cell cycle upon feeding. We demonstrate that nutrient restriction causes neural progenitors to arrest in G2 of the cell cycle with increased DNA content, and that nutrient availability triggers progenitors to re-enter the cell cycle at M phase. Initiation of the nutrient restriction-induced G2 arrest is rapamycin insensitive, but cell cycle re-entry requires mTOR. Finally, we show that activation of insulin receptor signaling is sufficient to increase neural progenitor cell proliferation in the absence of food. A G2 arrest mechanism provides an adaptive strategy to control brain development in response to nutrient availability by triggering a synchronous burst of cell proliferation when nutrients become available. This may be a general cellular mechanism that allows developmental flexibility during times of limited resources.

Trace elements in schizophrenia: a systematic review and meta-analysis of 39 studies (N = 5151 participants)

Context

The pathogenesis of schizophrenia appears to be multifaceted.

Objective

The aim of this meta-analysis of studies that investigated blood and hair concentrations of trace elements in people diagnosed with schizophrenia was to determine whether levels of trace elements in patients with schizophrenia differ from those in healthy individuals.

Data Sources

The PubMed, Scopus, and Web of Science databases were searched to January 2018.

Study Selection

Studies that compared concentrations of trace elements in patients with schizophrenia with those in healthy controls, in patients with schizophrenia under different treatment regimens, or in patients with schizophrenia at different stages of disease were included.

Data Extraction

Data on study and sample characteristics and measures of trace elements were extracted.

Results

Thirty-nine studies with a total of 5151 participants were included. Meta-analysis of combined plasma and serum data showed higher levels of copper, lower levels of iron, and lower levels of zinc among patients with schizophrenia vs controls without schizophrenia. Subgroup analyses confirmed the following: higher levels of copper in plasma, in users of typical antipsychotic drugs, and in males; lower levels of zinc in serum, in patients in Asia, in drug-naive/drug-free patients, and in inpatients; lower levels of iron in serum, in patients in Asia, in drug-naive/drug-free patients, in patients on antipsychotic drugs, in inpatients, in patients with acute or newly diagnosed schizophrenia, in patients with chronic or previously diagnosed schizophrenia, and in males; and lower levels of manganese in plasma and in patients with chronic or previously diagnosed schizophrenia.

Conclusions

This meta-analysis provides evidence of an excess of copper, along with deficiencies of zinc, iron, and manganese, in patients with schizophrenia.

Prenatal Maternal Stress and the Cascade of Risk to Schizophrenia Spectrum Disorders in Offspring

PURPOSE OF REVIEW

Disruptions in fetal development (via genetic and environmental pathways) have been consistently associated with risk for schizophrenia in a variety of studies. Although multiple obstetric complications (OCs) have been linked to schizophrenia, this review will discuss emerging evidence supporting the role of prenatal maternal stress (PNMS) in the etiology of schizophrenia spectrum disorders (SSD). In addition, findings linking PNMS to intermediate phenotypes of the disorder, such as OCs and premorbid cognitive, behavioral, and motor deficits, will be reviewed. Maternal immune and endocrine dysregulation will also be explored as potential mechanisms by which PNMS confers risk for SSD.

RECENT FINDINGS

PNMS has been linked to offspring SSD; however, findings are mixed due to inconsistent and retrospective assessments of PNMS and lack of specificity about SSD outcomes. PNMS is also associated with various intermediate phenotypes of SSD (e.g., prenatal infection/inflammation, decreased fetal growth, hypoxia-related OCs). Recent studies continue to elucidate the impact of PNMS while considering the moderating roles of fetal sex and stress timing, but it is still unclear which aspects of PNMS (e.g., type, timing) confer risk for SSD specifically. PNMS increases risk for SSD, but only in a small portion of fetuses exposed to PNMS. Fetal sex, genetics, and other environmental factors, as well as additional pre- and postnatal insults, likely contribute to the PNMS-SSD association. Longitudinal birth cohort studies are needed to prospectively illuminate the mechanisms that account for the variability in outcomes following PNMS.

Change in Brain Plasmalogen Composition by Exposure to Prenatal Undernutrition Leads to Behavioral Impairment of Rats

Epidemiological studies suggest that poor nutrition during pregnancy influences offspring predisposition to experience developmental and psychiatric disorders. Animal studies have shown that maternal undernutrition leads to behavioral impairment, which is linked to alterations in monoaminergic systems and inflammation in the brain. In this study, we focused on the ethanolamine plasmalogen of the brain as a possible contributor to behavioral disturbances observed in offspring exposed to maternal undernutrition. Maternal food or protein restriction between gestational day (GD) 5.5 and GD 10.5 resulted in hyperactivity of rat male adult offspring. Genes related to the phospholipid biosynthesis were found to be activated in the PFC, but not in the NAcc or striatum, in the offspring exposed to prenatal undernutrition. Corresponding to these gene activations, increased ethanolamine plasmalogen (18:0p-22:6) was observed in the PFC using mass spectrometry imaging. A high number of crossings and the long time spent in the center area were observed in the offspring exposed to prenatal undernutrition and were mimicked in adult rats via the intravenous injection of ethanolamine plasmalogen (18:0p-22:6) incorporated into the liposome. Additionally, plasmalogen (18:0p-22:6) increased only in the PFC, and not in the NAcc or striatum. These results suggest that brain plasmalogen is one of the key molecules to control behavior, and its injection using liposome is a potential therapeutic approach for cognitive impairment.SIGNIFICANCE STATEMENT Maternal undernutrition correlates to developmental and psychiatric disorders. Here, we found that maternal undernutrition in early pregnancy led to hyperactivity in rat male offspring and induced gene activation of phospholipid-synthesizing enzyme and elevation of ethanolamine plasmalogen (18:0p-22:6) level in the PFC. Intravenous injection of ethanolamine plasmalogen (18:0p-22:6) incorporated into the liposome maintained crossing activity and the activity was circumscribed to the center area for a long time period, as in prenatally undernourished offspring with aberrant behavior. Furthermore, the amount of ethanolamine plasmalogen (18:0p-22:6) increased in the PFC of the rat after injection. Our result suggests that brain plasmalogen is one of the key molecules to control behavior and that its injection using liposome is a potential therapeutic approach for cognitive impairment.

The involvement of astrocytes in early-life adversity induced programming of the brain

Early‐life adversity (ELA) in the form of stress, inflammation, or malnutrition, can increase the risk of developing psychopathology or cognitive problems in adulthood. The neurobiological substrates underlying this process remain unclear. While neuronal dysfunction and microglial contribution have been studied in this context, only recently the role of astrocytes in early‐life programming of the brain has been appreciated. Astrocytes serve many basic roles for brain functioning (e.g., synaptogenesis, glutamate recycling), and are unique in their capacity of sensing and integrating environmental signals, as they are the first cells to encounter signals from the blood, including hormonal changes (e.g., glucocorticoids), immune signals, and nutritional information. Integration of these signals is especially important during early development, and therefore we propose that astrocytes contribute to ELA induced changes in the brain by sensing and integrating environmental signals and by modulating neuronal development and function. Studies in rodents have already shown that ELA can impact astrocytes on the short and long term, however, a critical review of these results is currently lacking. Here, we will discuss the developmental trajectory of astrocytes, their ability to integrate stress, immune, and nutritional signals from the early environment, and we will review how different types of early adversity impact astrocytes.

CACNA1C Polymorphism (rs2283291) Is Associated with Schizophrenia in Chinese Males: A Case-Control Study

Recent research has shown that prenatal famine exposure may be one of the risk factors for schizophrenia and that people born in famine years may be at an increased risk of schizophrenia due to alteration of the DNA methylation of genes. In this study, the association of rs2283291/rs4648635 and the incidence of schizophrenia and prenatal famine exposure at the genetic level were investigated to provide clues to the pathogenesis of schizophrenia. A total of 960 participants were recruited, comprising 473 prenatal famine-exposed individuals (225 patients and 248 controls) and 487 prenatal non-famine-exposed individuals (220 patients and 267 controls). The association of prenatal famine, schizophrenia, and their interaction with DNA methylation levels was analyzed using SPSS and GMDR software. Gender stratification analysis revealed a significant association between the rs2283291 genotype and schizophrenia in male patients (P = 0.017), and difference still existed after correction by the Bonferroni method. It was also found that an increasing risk of schizophrenia was associated with rs2283291 in males (OR: 1.62, 95% CI: 1.13-2.33, P = 0.0086, AIC = 669.7) in an overdominant model. The results of gene-environment interaction and gene-gene interaction revealed no association with the risk of schizophrenia. This study reported for the first time that rs2283291 was associated with schizophrenia in Chinese males.

Prenatal Protein Malnutrition Produces Resistance to Distraction Similar to Noradrenergic Deafferentation of the Prelimbic Cortex in a Sustained Attention Task

Exposure to malnutrition early in development increases likelihood of neuropsychiatric disorders, affective processing disorders, and attentional problems later in life. Many of these impairments are hypothesized to arise from impaired development of the prefrontal cortex. The current experiments examine the impact of prenatal malnutrition on the noradrenergic and cholinergic axons in the prefrontal cortex to determine if these changes contribute to the attentional deficits seen in prenatal protein malnourished rats (6% casein vs. 25% casein). Because prenatally malnourished animals had significant decreases in noradrenergic fibers in the prelimbic cortex with spared innervation in the anterior cingulate cortex and showed no changes in acetylcholine innervation of the prefrontal cortex, we compared deficits produced by malnutrition to those produced in adult rats by noradrenergic lesions of the prelimbic cortex. All animals were able to perform the baseline sustained attention task accurately. However, with the addition of visual distractors to the sustained attention task, animals that were prenatally malnourished and those that were noradrenergically lesioned showed cognitive rigidity, i.e., were less distractible than control animals. All groups showed similar changes in behavior when exposed to withholding reinforcement, suggesting specific attentional impairments rather than global difficulties in understanding response rules, bottom-up perceptual problems, or cognitive impairments secondary to dysfunction in sensitivity to reinforcement contingencies. These data suggest that prenatal protein malnutrition leads to deficits in noradrenergic innervation of the prelimbic cortex associated with cognitive rigidity.

Maternal stress, prenatal medical illnesses and obstetric complications: Risk factors for schizophrenia spectrum disorder, bipolar disorder and major depressive disorder

Maternal stress and medical illnesses during early life are well-documented environmental indicators of an increased risk of schizophrenia. Few studies, conversely, have confirmed an association with major affective disorders. The present study examined the impact of maternal stress, medical illnesses and obstetric complications on the development of severe mental disorder in 240 patients with a diagnosis of schizophrenia spectrum disorder, bipolar disorder, or major depressive disorder and matched with 85 controls. Mothers of participants were asked about stressful events during pregnancy using the Social Readjustment Scale; information on prenatal/perinatal illnesses were acquired from medical records. Schizophrenia spectrum disorder was positively associated with maternal stress (OR = 2.16), infections (OR = 7.67), inadequate weight gain (OR = 9.52) during pregnancy, and peripartum asphyxia (OR = 4.00). An increased risk of bipolar disorder was associated with head circumference < 32 cm at birth (OR = 5.40) and inversely with inadequate weight gain (OR = 0.29). Major depressive disorder diagnosis was inversely related to inadequate weight gain (OR = 0.22). These results support a role for maternal stress, medical illnesses and obstetric complications as risk factors for subsequent severe mental illness in adulthood. Further research is needed, especially with regard to affective disorders.

Iron as a model nutrient for understanding the nutritional origins of neuropsychiatric disease

Adequate nutrition during the pre- and early-postnatal periods plays a critical role in programming early neurodevelopment. Disruption of neurodevelopment by nutritional deficiencies can result not only in lasting functional deficits, but increased risk of neuropsychiatric disease in adulthood. Historical periods of famine such as the Dutch Hunger Winter and the Chinese Famine have provided foundational evidence for the long-term effects of developmental malnutrition on neuropsychiatric outcomes. Because neurodevelopment is a complex process that consists of many nutrient- and brain-region-specific critical periods, subsequent clinical and pre-clinical studies have aimed to elucidate the specific roles of individual macro- and micronutrient deficiencies in neurodevelopment and neuropsychiatric pathologies. This review will discuss developmental iron deficiency (ID), the most common micronutrient deficiency worldwide, as a paradigm for understanding the role of early-life nutrition in neurodevelopment and risk of neuropsychiatric disease. We will review the epidemiologic data linking ID to neuropsychiatric dysfunction, as well as the underlying structural, cellular, and molecular mechanisms that are thought to underlie these lasting effects. Understanding the mechanisms driving lasting dysfunction and disease risk is critical for development and implementation of nutritional policies aimed at preventing nutritional deficiencies and their long-term sequelae.