UCP2 induced by natural birth regulates neuronal differentiation of the hippocampus and related adult behavior

Effect of cesarean section on the risk of autism spectrum disorders/attention deficit hyperactivity disorder in offspring: a meta-analysis

PURPOSE

This study was conducted to investigate the relationship between cesarean section (CS) offspring and autism spectrum disorders (ASD)/attention deficit hyperactivity disorder (ADHD).

METHODS

Searching of the databases (PubMed, Web of Science, Embase, and Cochrane Library) for studies on the relationship between mode of delivery and ASD/ADHD until August 2022. The primary outcome was the incidence of ASD/ADHD in the offspring.

RESULTS

This meta-analysis included 35 studies (12 cohort studies and 23 case-control studies). Statistical results showed a higher risk of ASD (odds ratio (OR) = 1.25, P < 0.001) and ADHD (OR = 1.11, P < 0.001) in CS offspring compared to the VD group. Partial subgroup analysis showed no difference in ASD risk between CS and VD offspring in sibling-matched groups (OR = 0.98, P = 0.625). The risk of ASD was higher in females (OR = 1.66, P = 0.003) than in males (OR = 1.17, P = 0.004) in the CS offspring compared with the VD group. There was no difference in the risk of ASD between CS under regional anesthesia group and VD group (OR = 1.07, P = 0.173). However, the risk of ASD was higher in the CS offspring under general anesthesia than in the VD offspring (OR = 1.62, P < 0.001). CS offspring developed autism (OR = 1.38, P = 0.011) and pervasive developmental disorder-not otherwise specified (OR = 1.46, P = 0.004) had a higher risk than VD offspring, but there was no difference in Asperger syndrome (OR = 1.19, P = 0.115). Offspring born via CS had a higher incidence of ADHD in different subgroup analyses (sibling-matched, type of CS, and study design).

CONCLUSIONS

In this meta-analysis, CS was a risk factor for ASD/ADHD in offspring compared with VD.

Changes in ADAR RNA editing patterns in CMV and ZIKV congenital infections

BACKGROUND

RNA editing is a process that increases transcriptome diversity, often through Adenosine Deaminases Acting on RNA (ADARs) that catalyze the deamination of adenosine to inosine. ADAR editing plays an important role in regulating brain function and immune activation, and is dynamically regulated during brain development. Additionally, the ADAR1 p150 isoform is induced by interferons in viral infection and plays a role in antiviral immune response. However, the question of how virus-induced ADAR expression affects host transcriptome editing remains largely unanswered. This question is particularly relevant in the context of congenital infections, given the dynamic regulation of ADAR editing during brain development, the importance of this editing for brain function, and subsequent neurological symptoms of such infections, including microcephaly, sensory issues, and other neurodevelopmental abnormalities. Here, we begin to address this question, examining ADAR expression in publicly available datasets of congenital infections of human cytomegalovirus (HCMV) microarray expression data, as well as mouse cytomegalovirus (MCMV) and mouse/ human induced pluripotent neuroprogenitor stem cell (hiNPC) Zika virus (ZIKV) RNA-seq data.

RESULTS

We found that in all three datasets, ADAR1 was overexpressed in infected samples compared to uninfected samples. In the RNA-seq datasets, editing rates were also analyzed. In all mouse infections cases, the number of editing sites was significantly increased in infected samples, albeit this was not the case for hiNPC ZIKV samples. Mouse ZIKV samples showed altered editing of well-established protein-recoding sites such as Gria3, Grik5, and Nova1, as well as editing sites that may impact miRNA binding.

CONCLUSIONS

Our findings provide evidence for changes in ADAR expression and subsequent dysregulation of ADAR editing of host transcriptomes in congenital infections. These changes in editing patterns of key neural genes have potential significance in the development of neurological symptoms, thus contributing to neurodevelopmental abnormalities. Further experiments should be performed to explore the full range of editing changes that occur in different congenital infections, and to confirm the specific functional consequences of these editing changes.

Decoding the neurocircuitry of gut feelings: Region-specific microbiome-mediated brain alterations

Research in the last decade has unveiled a crucial role for the trillions of microorganisms that reside in the gut in influencing host neurodevelopment across the lifespan via the microbiota-gut-brain axis. Studies have linked alterations in the composition, complexity, and diversity of the gut microbiota to changes in behaviour including abnormal social interactions, cognitive deficits, and anxiety- and depressive-like phenotypes. Moreover, the microbiota has been linked with neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. Interestingly, there appears to be specific brain regions governing the neurocircuitry driving higher cognitive function that are susceptible to influence from manipulations to the host microbiome. This review will aim to elucidate the region-specific effects mediated by the gut microbiota, with a focus on translational animal models and some existing human neuroimaging data. Compelling preclinical evidence suggests disruption to normal microbiota-gut-brain signalling can have detrimental effects on the prefrontal cortex, amygdala, hippocampus, hypothalamus, and striatum. Furthermore, human neuroimaging studies have unveiled a role for the microbiota in mediating functional connectivity and structure of specific brain regions that can be traced back to neurocognition and behavioural output. Understanding these microbiota-mediated changes will aid in identifying unique therapeutic targets for treating neurological disorders associated with these regions.

Nascer de cesariana e associação com quociente de inteligência em adolescentes: contribuição do Consórcio de Coortes RPS (Ribeirão Preto, Pelotas e São Luís), Brasil

O objetivo do estudo foi avaliar a associação entre a cesariana e o quociente de inteligência (QI) em adolescentes do Município de São Luís, Maranhão, Brasil. Trata-se de um estudo longitudinal utilizando dados da coorte de nascimento em São Luís, iniciado no ano de 1997. A abordagem ocorreu na terceira fase da coorte, em 2016, com adolescente aos 18 e 19 anos de idade. A variável de exposição foi a via de nascimento e a variável de desfecho foi o QI, mensurada a partir da aplicação da terceira versão da Escala de Inteligência Wechsler para Adultos (WAIS-III). Na análise dos dados verificou-se a média do QI segundo as covariáveis e utilizou-se a regressão linear multivariada. Para controlar os fatores de confundimento foi elaborado um modelo teórico utilizando o gráfico acíclico dirigido. As variáveis confundidoras foram as socioeconômicas no momento do nascimento e as variáveis perinatais. A média do QI dos adolescentes foi 101,4. Na análise bruta, o QI dos adolescentes nascidos de cesariana foi 5,8 pontos maior em relação aos nascidos de parto vaginal (IC95%: 3,8; 7,7, p ≤ 0,001), com significância estatística. Na análise multivariada, o valor reduziu para 1,9 (IC95%: -0,5; 3,6, p = 0,141), sem significância estatística. O resultado do estudo mostrou que a cesariana não está associada ao QI dos adolescentes nessa amostra e reflete que as diferenças encontradas podem ser explicadas por outros fatores, como aspectos socioeconômicos e perinatais.

Expression and hormone regulation of UCP2 in goat uterus

Pregnancy success is closely related to the molecular mechanisms that control energy metabolism balance. However, the mechanisms have not been fully understood. Uncoupling protein 2 (UCP2) plays a physiological role by regulating energy metabolism in numerous tissues. In this study, we determined the expression and hormone regulation of UCP2 in goat uterus. UCP2 is expressed in the luminal and glandular epithelia of goat uterus during early pregnancy, as revealed by in situ hybridization and immunohistochemistry conducted on pregnant goats. The signals were detected from day 0 (D0) to D30 of pregnancy, though weak on D16 (the adhesion period). The low levels of UCP2 on D16 were confirmed by RT-qPCR and western blot. In goat uterus and endometrial epithelial cells (EECs), UCP2 was up-regulated by progesterone and estrogen. In addition, after goat EECs were treated with genipin (an inhibitor of UCP2), not only UCP2 expression but also cell proliferation was inhibited. Collectively, UCP2 is dynamically expressed in goat uterus and can affect EEC proliferation, suggesting that it may participate in regulating the energy metabolism balance of goat uterus during early pregnancy.

Endothelial Cells Mediated by UCP2 Control the Neurogenic-to-Astrogenic Neural Stem Cells Fate Switch During Brain Development

During mammalian cortical development, neural stem/progenitor cells (NSCs) gradually alter their characteristics, and the timing of generation of neurons and glial cells is strictly regulated by internal and external factors. However, whether the blood vessels located near NSCs affect the neurogenic-to-gliogenic transition remain unknown. Here, it is demonstrated that endothelial uncoupling protein 2 (UCP2) deletion reduces blood vessel diameter and affects the transition timing of neurogenesis and gliogenesis. Deletion of endothelial UCP2 results in a persistent increase in astrocyte production at the postnatal stage. Mechanistically, the endothelial UCP2/ROS/ERK1/2 pathway increases chymase-1 expression to enhance angiotensin II (AngII) secretion outside the brain endothelium. The endotheliocyte-driven AngII-gp130-JAK-STAT pathway also regulates gliogenesis initiation. Moreover, endothelial UCP2 knockdown decreases human neural precursor cell (hNPC) differentiation into neurons and accelerates hNPC differentiation into astrocytes. Altogether, this work provides mechanistic insights into how endothelial UCP2 regulates the neurogenic-to-gliogenic fate switch in the developing neocortex.

Animal Models for Assessing Impact of C-Section Delivery on Biological Systems

There has been a significant increase in Caesarean section (C-section) births worldwide over the past two decades and although it is can be a life-saving procedure, the enduring effects on host physiology are now undergoing further scrutiny. Indeed, epidemiological data have linked C-section birth with multiple immune, metabolic and neuropsychiatric diseases. Birth by C-section is known to alter the colonisation of the neonatal gut microbiota (with C-section delivered infants lacking vaginal microbiota associated with passing along the birth canal), which in turn can impact the development and maintenance of many important biological systems. Appropriate animal models are key to disentangling the role of missing microbes in brain health and disease in C-section births. In this review of preclinical studies, we interrogate the effects of C-section birth on the development (and maintenance) of several biological systems and we discuss the involvement of the gut microbiome on C-section-related alterations.

Early-life oxytocin attenuates the social deficits induced by caesarean-section delivery in the mouse

The oxytocin (OXT) system has been strongly implicated in the regulation of social behaviour and anxiety, potentially contributing to the aetiology of a wide range of neuropathologies. Birth by Caesarean-section (C-section) results in alterations in microbiota diversity in early-life, alterations in brain development and has recently been associated with long-term social and anxiety-like behaviour deficits. In this study, we assessed whether OXT intervention in the early postnatal period could reverse C-section-mediated effects on behaviour, and physiology in early life and adulthood. Following C-section or per vaginum birth, pups were administered with OXT (0.2 or 2 μg/20 μl; s.c.) or saline daily from postnatal days 1-5. We demonstrate that early postnatal OXT treatment has long-lasting effects reversing many of the effects of C-section on mouse behaviour and physiology. In early-life, high-dose OXT administration attenuated C-section-mediated maternal attachment impairments. In adulthood, low-dose OXT restored social memory deficits, some aspects of anxiety-like behaviour, and improved gastrointestinal transit. Furthermore, as a consequence of OXT intervention in early life, OXT plasma levels were increased in adulthood, and dysregulation of the immune response in C-section animals was attenuated by both doses of OXT treatment. These findings indicate that there is an early developmental window sensitive to manipulations of the OXT system that can prevent lifelong behavioural and physiological impairments associated with mode of birth.

Three kinds of caesarean sections: the foetal/neonatal perspective

In the age of hospital births, it is commonplace to contrast the vaginal route and the abdominal route as the basic classification. From the "point of view" of the foetus/neonate, we provide reasons to contrast "birth without labour" (that is birth by pre-labour caesarean section) and all the other vaginal and abdominal modes of birth. From a great diversity of theoretical reasons, one can anticipate that babies born by pre-labour caesarean sections are different from the others. We also provide reasons to popularize the concepts of "in labour non-emergency caesarean sections" and "planned in-labour caesarean sections".

Learning Disabilities in Reading and Writing and Type of Delivery in Twin Births

The aim of this study was to analyse the relationship between the type of delivery (vaginal or caesarean), as a risk factor, and the likelihood of having learning disabilities in reading (reading accuracy) and writing (phonetic and visual orthography), controlling for the interaction and/or confounding effect of gestational, obstetric, and neonatal variables (maternal age at delivery, gestational age, foetal presentation, Apgar 1, and newborn weight) among six-year-old children born in twin births. In this retrospective cohort study, the exposed and non-exposed cohorts consisted of children born by caesarean section and vaginal delivery, respectively. A total of 124 children born in twin births were evaluated in year one of primary education. Intelligence was measured using the K-BIT test; reading and writing variables were evaluated using the Evalúa-1 battery of tests, and clinical records were used to measure gestational, obstetric, and neonatal variables. Binary logistic regressions applied to each dependent variable indicated that caesarean delivery is a possible independent risk factor for difficulties in reading accuracy and phonetic and visual orthography. Future research using larger samples of younger children is required to analyse the relationship between obstetric and neonatal variables and the different basic indicators of reading and writing.

MC4R Signaling in Dorsal Raphe Nucleus Controls Feeding, Anxiety, and Depression

Major depressive disorder is associated with weight loss and decreased appetite; however, the signaling that connects these conditions is unclear. Here, we show that MC₄R signaling in the dorsal raphe nucleus (DRN) affects feeding, anxiety, and depression. DRN infusion of α-MSH decreases DRN neuronal activation and feeding. DRN MC₄R is expressed in GABAergic PRCP-producing neurons. DRN selective knockdown of PRCP (Prcp^DRNKD), an enzyme inactivating α-MSH, decreases feeding and DRN neuronal activation. Interestingly, Prcp^DRNKD mice present lower DRN serotonin levels and depressive-like behavior. Similarly, PRCP-ablated MC₄R mice (Prcp^MC4RKO) show metabolic and behavioral phenotypes comparable to those of Prcp^DRNKD mice. Selective PRCP re-expression in DRN MC₄R neurons of Prcp^MC4RKO mice partially reverses feeding, while fully restoring mood behaviors. Chemogenetic inhibition of DRN MC₄R neurons induces anxiety, depression, and reduced feeding, whereas chemogenetic activation reverses these effects. Our results indicate that MC₄R signaling in DRN plays a role in feeding, anxiety, and depression.

Brain Volumes in Mice are Smaller at Birth After Term or Preterm Cesarean Section Delivery

The rate of cesarean section (CS) delivery has steadily increased over the past decades despite epidemiological studies reporting higher risks of neonatal morbidity and neurodevelopmental disorders. Yet, little is known about the immediate impact of CS birth on the brain, hence the need of experimental studies to evaluate brain parameters following this mode of delivery. Using the solvent clearing method iDISCO and 3D imaging technique, we report that on the day of birth, whole-brain, hippocampus, and striatum volumes are reduced in CS-delivered as compared to vaginally-born mice, with a stronger effect observed in preterm CS pups. These results stress the impact of CS delivery, at term or preterm, during parturition and at birth. In contrast, cellular activity and apoptosis are reduced in mice born by CS preterm but not term, suggesting that these early-life processes are only impacted by the combination of preterm birth and CS delivery.

Are there adverse outcomes for child health and development following caesarean section delivery? Can we justify using elective caesarean section to prevent obstetric pelvic floor damage?

INTRODUCTION AND HYPOTHESIS

Elective pre-labour Caesarean section (CS) delivery is widely regarded as the panacea for all pelvic floor dysfunction despite substantial epidemiological evidence that it is only partially protective. To demand a CS is also considered a right for the well-counselled patient, even without an elevated risk of incontinence or prolapse. In recent years there has been increasing data on possible adverse health outcomes for children delivered by CS over those delivered vaginally. This includes respiratory illness, atopic conditions, obesity, diabetes and other severe auto-immune diseases. Concern has also been raised over possible impacts on cognitive and neuropsychological development in these children. Often the response has been to dismiss these outcomes as a result of the indication for the CS birth such as antenatal compromise or maternal disease. However the marked increase in non-medical Caesarean delivery throughout many regions of the world has allowed us to better distinguish these contributing factors.

METHODS

This narrative review looks at some of the more recent evidence on adverse health and developmental outcomes associated with CS, particularly pre-labour CS and the implications for the long term health of our society.

RESULTS

Epidemiological studies and animal research indicate an increased risk of negative impacts on child physical health and neuro-cognitive development aftercaesarean section delivery, particularly pre-labour Caesarean section, compared with vaginal delivery. This elevated risk persists after correction forobstetric and maternal factors.

CONCLUSION

Caesarean section delivery can result in adverse outcomes for infant, maternal and societal wellbeing. Elective Caesarean section, purely to potentially minimise pelvic floor dysfunction, cannot be justified.

Mitochondrial uncoupling protein 2 is regulated through heterogeneous nuclear ribonucleoprotein K in lead exposure models

Synaptic plasticity plays an important role in learning and memory in the developing hippocampus. However, the precise molecular mechanism in lead exposure models remains to be studied. UCP2, an inner mitochondrial anion carrier, regulates synaptic plasticity through uncoupling neurons. And hnRNP K, an RNA binding protein, plays a role in modulating the expression of transcripts coding synaptic plasticity. We aim to investigate whether lead exposure affects UCP2 and hnRNP K expression levels. The Sprague-Dawley rats were exposed to different lead acetate concentrations (0 g/l, 0.5 g/l, 2.0 g/l) during gestational and lactational periods. PC12 cells were also exposed to different lead acetate concentrations (0 μM, 1 μM and 100 μM). We found that the expression levels of UCP2 and hnRNP K had significant declines in the lead exposure rat hippocampus and PC12 cells. Furthermore, the up-regulation of hnRNP K expression level could reverse the expression level of UCP2 in lead exposure models. In conclusion, these results suggest that lead exposure can reduce the expression level of UCP2 which is mediated by decreasing the expression level of hnRNP K.

Inhibition of Uncoupling Protein 2 Enhances the Radiosensitivity of Cervical Cancer Cells by Promoting the Production of Reactive Oxygen Species

Objective

The mechanism of enhanced radiosensitivity induced by mitochondrial uncoupling protein UCP2 was investigated in HeLa cells to provide a theoretical basis as a novel target for cervical cancer treatment.

Methods

HeLa cells were irradiated with 4 Gy X-radiation at 1.0 Gy/min. The expression of UCP2 mRNA and protein was assayed by real-time quantitative polymerase chain reaction and western blotting. UCP2 siRNA and negative control siRNA fragments were constructed and transfected into HeLa cells 24 h after irradiation. The effect of UCP2 silencing and irradiation on HeLa cells was determined by colony formation, CCK-8 cell viability, γH2AX immunofluorescence assay of DNA damage, Annexin V-FITC/PI apoptosis assay, and propidium iodide cell cycle assay. The effects on mitochondrial structure and function were investigated with fluorescent probes including dichlorodihydrofluorescein diacetate (DCFH-DA) assay of reactive oxygen species (ROS), rhodamine 123, and MitoTracker Green assay of mitochondrial structure and function.

Results

Irradiation upregulated UCP2 expression, and UCP2 knockdown decreased the survival of irradiated HeLa cells. UCP2 silencing sensitized HeLa cells to irradiation-induced DNA damage and led to increased apoptosis, cell cycle arrest in G2/M, and increased mitochondrial ROS. Increased radiosensitivity was associated with an activation of P53, decreased Bcl-2, Bcl-xl, cyclin B, CDC2, Ku70, and Rad51 expression, and increased Apaf-1, cytochrome c, caspase-3, and caspase-9 expression.

Conclusions

UCP2 inhibition augmented the radiosensitivity of cervical cancer cells, and it may be a potential target of radiotherapy of advanced cervical cancer.

Prefrontal Cortical and Behavioral Adaptations to Surgical Delivery Mediated by Metabolic Principles

We previously observed an association between mode of delivery and brain mitochondrial mechanisms in pups. We also showed that mitochondrial processes impact adult behavior. However, no experimental data is available to causally connect mode of delivery with cellular processes of neurons in the cerebral cortex and adult behavior. Here we show that surgical delivery of pups alters mitochondrial dynamics and spine synapses of layer 3 pyramidal neurons of the prefrontal cortex compared to the values of mice delivered vaginally. These alterations in ultrastructure seen in adult mice delivered surgically were associated with the development of behavioral phenotypes resembling those characteristic of animal models of psychiatric illness. This included impaired performance in prepulse inhibition as well as hyperlocomotion in the open field and elevated plus maze tests. Knocking out a mitochondria-related gene, UCP-2, blocked cellular and behavioral adaptations induced by surgical delivery. These results highlight a crucial role for brain mitochondrial adaptations in the process of birth to affect neuronal circuitry in support of normal and altered adult behaviors. Further, these findings were supported with neuroimaging data from human neonates delivered vaginally and surgically, suggesting that the murine findings have human clinical relevance.

Type of delivery and reading, writing, and arithmetic learning in twin births

This study analyses, in children born in twin births, the relationship between reading, writing and arithmetic learning, on the one hand, and type of delivery, on the other, controlling for the effect of interaction and/or confusion of third variables (maternal age at delivery, gestational age, fetal position, birthweight, 1-min Apgar score). In the planned retrospective cohort design, the exposed cohort consisted of children born by caesarean section, and the non-exposed cohort was comprised of children born vaginally. One hundred and twenty-four children born of twin births were evaluated during their first year of primary school: K-BIT tests were used to measure intelligence; the Evalúa-1 battery was used to assess reading, writing, and arithmetic ability; and the children's clinical histories were analysed for obstetric and neonatal variables. After applying binary logistic regressions for each dependent variable, it was found that caesarean delivery in twin births appeared as a possible independent risk factor for specific learning disabilities (LDs) in reading, writing, and arithmetic. Based on these results, further research using larger samples and at more advanced ages is required in order to analyse the influence of obstetric and neonatal variables on the processes underlying specific LDs.

Type of Delivery, Neuropsychological Development and Intelligence in Twin Births

Based on a retrospective cohort design with 6-year-old children born in twin births, the relationship between verbal, non-verbal, global neuropsychological development, general intelligence and type of delivery has been studied. To this end, the possible effect of third gestational, obstetric and neonatal variables, such as maternal age at delivery, fetal presentation, gestational age, newborn weight and Apgar at minute one, was controlled. The exposed cohort includes children born by cesarean section, and the unexposed cohort is composed of children born vaginally with or without induction. A total of 124 children were evaluated in their 1st year of primary school using the Child Neuropsychological Maturity Questionnaire, Kaufman's Intelligence Test and the medical histories of the children collected after birth. By means of binary logistic regression analysis, it has been found that the type of delivery is presented as an independent risk factor for disorders in verbal, non-verbal and global development and for the general intellectual difficulties of children born of multiple births. These results suggest the need to analyze in future prospective studies with broader samples the relationship between different types of obstetric and perinatal variables of birth type and infant neuropsychological development and general intelligence, in order to prevent possible psychological alterations from birth.

The Role of PGC-1α/UCP2 Signaling in the Beneficial Effects of Physical Exercise on the Brain

In understanding the pathology of neurological diseases, the role played by brain energy metabolism is gaining prominence. Animal models have demonstrated that regular physical exercise improves brain energy metabolism while also providing antidepressant, anxiolytic, antioxidant and neuroprotective functions. This review summarizes the latest evidence on the roles played by peroxisome proliferator-activated receptor gamma (PPAR-γ) coactivator 1-alpha (PGC-1α) and mitochondrial uncoupling protein (UCP) in this scenario. The beneficial effects of exercise seem to depend on crosstalk between muscles and nervous tissue through the increased release of muscle irisin during exercise.

Cesarean Delivery Impacts Infant Brain Development

BACKGROUND AND PURPOSE

The cesarean delivery rate has increased globally in the past few decades. Neurodevelopmental outcomes associated with cesarean delivery are still unclear. This study investigated whether cesarean delivery has any effect on the brain development of offspring.

MATERIALS AND METHODS

A total of 306 healthy children were studied retrospectively. We included 3 cohorts: 2-week-old neonates (cohort 1, n = 32/11 for vaginal delivery/cesarean delivery) and 8-year-old children (cohort 2, n = 37/23 for vaginal delivery/cesarean delivery) studied at Arkansas Children's Hospital, and a longitudinal cohort of 3-month to 5-year-old children (cohort 3, n = 164/39 for vaginal delivery/cesarean delivery) studied independently at Brown University. Diffusion tensor imaging, myelin water fraction imaging, voxel-based morphometry, and/or resting-state fMRI data were analyzed to evaluate white matter integrity, myelination, gray matter volume, and/or functional connectivity, respectively.

RESULTS

While not all MR imaging techniques were shared across the institutions/cohorts, post hoc analyses showed similar results of potential effects of cesarean delivery. The cesarean delivery group in cohort 1 showed significantly lower white matter development in widespread brain regions and significantly lower functional connectivity in the brain default mode network, controlled for a number of potential confounders. No group differences were found in cohort 2 in white matter integrity or gray matter volume. Cohort 3 had significantly different trajectories of white matter myelination between groups, with those born by cesarean delivery having reduced myelin in infancy but normalizing with age.

CONCLUSIONS

Cesarean delivery may influence infant brain development. The impact may be transient because similar effects were not observed in older children. Further prospective and longitudinal studies may be needed to confirm these novel findings.

Moderating effect of mode of delivery on the genetics of intelligence: Explorative genome-wide analyses in ALSPAC

INTRODUCTION

Intelligence is a core construct of individual differences in cognitive abilities and a strong predictor of important life outcomes. Within recent years, rates of cesarean section have substantially increased globally, though little is known about its effect on neurodevelopmental trajectories. Thus, we aimed to investigate the influence of delivery by cesarean section on the genetics of intelligence in children.

METHODS

Participants were recruited through the Avon Longitudinal Study of Parents and Children (ALSPAC). Intelligence was measured by the Wechsler Intelligence Scale for Children (WISC). Genotyping was performed using the Illumina Human Hap 550 quad genome-wide SNP genotyping platform and was followed by imputation using MACH software. Genome-wide interaction analyses were conducted using linear regression.

RESULTS

A total of 2,421 children and 2,141,747 SNPs were subjected to the genome-wide interaction analyses. No variant reached genome-wide significance. The strongest interaction was observed at rs17800861 in the GRIN2A gene (β = -3.43, 95% CI = -4.74 to -2.12, p = 2.98E-07). This variant is predicted to be located within active chromatin compartments in the hippocampus and may influence binding of the NF-kappaB transcription factor.

CONCLUSIONS

Our results may indicate that mode of delivery might have a moderating effect on genetic disposition of intelligence in children. Studies of considerable sizes (>10,000) are likely required to more robustly detect variants governing such interaction. In summary, the presented findings prompt the need for further studies aimed at increasing our understanding of effects various modes of delivery may have on health outcomes in children.

Birth delivery mode alters perinatal cell death in the mouse brain

Labor and a vaginal delivery trigger changes in peripheral organs that prepare the mammalian fetus to survive ex utero. Surprisingly little attention has been given to whether birth also influences the brain, and to how alterations in birth mode affect neonatal brain development. These are important questions, given the high rates of cesarean section (C-section) delivery worldwide, many of which are elective. We examined the effect of birth mode on neuronal cell death, a widespread developmental process that occurs primarily during the first postnatal week in mice. Timed-pregnant dams were randomly assigned to C-section deliveries that were yoked to vaginal births to carefully match gestation length and circadian time of parturition. Compared with rates of cell death just before birth, vaginally-born offspring had an abrupt, transient decrease in cell death in many brain regions, suggesting that a vaginal delivery is neuroprotective. In contrast, cell death was either unchanged or increased in C-section-born mice. Effects of delivery mode on cell death were greatest for the paraventricular nucleus of the hypothalamus (PVN), which is central to the stress response and brain-immune interactions. The greater cell death in the PVN of C-section-delivered newborns was associated with a reduction in the number of PVN neurons expressing vasopressin at weaning. C-section-delivered mice also showed altered vocalizations in a maternal separation test and greater body mass at weaning. Our results suggest that vaginal birth acutely impacts brain development, and that alterations in birth mode may have lasting consequences.

Protective Role of UCP2 in Oxidative Stress and Apoptosis during the Silent Phase of an Experimental Model of Epilepsy Induced by Pilocarpine

Neuroprotection is a desirable process in many neurological disorders, yet complex mechanisms involved in this field are not completely understood. The pilocarpine epilepsy model causes potent, seizure-induced excitotoxicity cell death and mitochondria impairment. The present study is aimed at investigating the role of UCP2, a ROS negative regulator, in the neuroprotection after cholinergic insult. Our data demonstrated that UCP2 expression was augmented in the rat hippocampus 3 days after status epilepticus (SE), reaching a peak on the fifth day, then returning to basal levels. Concomitantly, phospho-AKT expression levels were higher in the hippocampus during the early silent phase (5 days after SE). Additionally, it was demonstrated that the blockade of UCP2 by antisense oligonucleotides (ASO) in SE rats successfully diminished both UCP2 mRNA and protein contents. SE ASO rats presented increased mitochondrial proapoptotic factor expression, caspase-3 activity, inflammatory cytokine expression, and ROS formation. Moreover, ASO treatment diminished p-AKT expression and antioxidant enzyme activities after pilocarpine insult. In conclusion, the present results highlight the neuroprotective actions of UCP2, acting in the inhibition of apoptotic factors and oxidative stress, to increase neuron survival after SE onset.

Uncoupling Protein 2 Inhibition Exacerbates Glucose Fluctuation-Mediated Neuronal Effects

Though glucose fluctuations have been considered as an adverse factor for the development of several diabetes-related complications, their impact in the central nervous system is still not fully elucidated. This study was conducted to evaluate the responses of neuronal cells to different glycemic exposures alongside to elucidate the role of uncoupling protein 2 (UCP2) in regulating such responses. To achieve our goals, primary cortical neurons were submitted to constant high (HG)/low (LG) or glucose level variations (GVs), and the pharmacological inhibition of UCP2 activity was performed using genipin. Results obtained show that GV decreased neuronal cells' viability, mitochondrial membrane potential, and manganese superoxide dismutase activity and increased reactive oxygen species (ROS) production. GV also caused an increase in the glutathione/glutathione disulfide ratio and in the protein expression levels of nuclear factor E2-related factor 2 (NRF2), UCP2, NADH-ubiquinone oxidoreductase chain 1 (ND1), and mitochondrially encoded cytochrome c oxidase I (MTCO1), both mitochondrial DNA encoded subunits of the electron transport chain. Contrariwise, genipin abrogated all those compensations and increased the levels of caspase 3-like activity, potentiated mitochondrial ROS levels, and the loss of neuronal synaptic integrity, decreased the protein expression levels of NRF1, and increased the protein expression levels of UCP5. Further, in the control and LG conditions, genipin increased mitochondrial ROS and the protein expression levels of UCP4, postsynaptic density protein 95 (PSD95), ND1, and MTCO1. Overall, these observations suggest that UCP2 is in the core of neuronal cell protection and/or adaptation against GV-mediated effects and that other isoforms of neuronal UCPs can be upregulated to compensate the inhibition of UCP2 activity.

Developmental Sex Differences in the Metabolism of Cardiolipin in Mouse Cerebral Cortex Mitochondria

Cardiolipin (CL) is a mitochondrial-specific phospholipid. CL content and acyl chain composition are crucial for energy production. Given that estradiol induces CL synthesis in neurons, we aimed to assess CL metabolism in the cerebral cortex (CC) of male and female mice during early postnatal life, when sex steroids induce sex-dimorphic maturation of the brain. Despite the fact that total amount of CL was similar, its fatty acid composition differed between males and females at birth. In males, CL was more mature (lower saturation ratio) and the expression of the enzymes involved in synthetic and remodeling pathways was higher, compared to females. Importantly, the sex differences found in CL metabolism were due to the testosterone peak that male mice experience perinatally. These changes were associated with a higher expression of UCP-2 and its activators in the CC of males. Overall, our results suggest that the perinatal testosterone surge in male mice regulates CL biosynthesis and remodeling in the CC, inducing a sex-dimorphic fatty acid composition. In male's CC, CL is more susceptible to peroxidation, likely explaining the testosterone-dependent induction of neuroprotective molecules such as UCP-2. These differences may account for the sex-dependent mitochondrial susceptibility after perinatal hypoxia/ischemia.

Disrupted mitochondrial genes and inflammation following stroke

AIMS

Determine the subacute time course of mitochondria disruption, cell death, and inflammation in a rat model of unilateral motor cortical ischemic stroke.

MAIN METHODS

Rats received unilateral ischemia of the motor cortex and were tested on behavioral tasks to determine impairments. Animals were euthanized at 24h, 72h and 144h and mRNA expression of key mitochondria proteins and indicators of inflammation, apoptosis and potential regenerative processes in ipsilesion cortex and striatum, using RT-qPCR. Mitochondrial proteins were examined at 144h using immunoblot analysis.

KEY FINDINGS

Rats with stroke induced-behavioral deficits had sustained, 144h post-lesion, decreases in mitochondrial-encoded electron transport chain proteins NADH dehydrogenase subunit-1 and cytochrome c oxidase subunit-1 (mRNA and protein) and mitochondrial DNA content in perilesion motor and sensory cortex. Uncoupling-protein-2 gene expression, but not superoxide dismutase-2, remained elevated in ipsilateral cortex and striatum at this time. Cortical inflammatory cytokine, interleukin-6, was increased early and was followed by increased macrophage marker F4/80 after stroke. Cleaved caspase-3 activation was elevated in cortex and growth associated protein-43 was elevated in the cortex and striatum six days post-lesion.

SIGNIFICANCE

We identified a relationship between three disrupted pathways, (1) sustained loss of mitochondrial proteins and mitochondrial DNA copy number in the cortex linked to decreased mitochondrial gene transcription; (2) early inflammatory response mediated by interleukin- 6 followed by macrophages; (3) apoptosis in conjunction with the activation of regenerative pathways. The stroke-induced spatial and temporal profiles lay the foundation to target pharmacological therapeutics to these three pathways.

Hypothalamic leptin action is mediated by histone deacetylase 5

Hypothalamic leptin signalling has a key role in food intake and energy-balance control and is often impaired in obese individuals. Here we identify histone deacetylase 5 (HDAC5) as a regulator of leptin signalling and organismal energy balance. Global HDAC5 KO mice have increased food intake and greater diet-induced obesity when fed high-fat diet. Pharmacological and genetic inhibition of HDAC5 activity in the mediobasal hypothalamus increases food intake and modulates pathways implicated in leptin signalling. We show HDAC5 directly regulates STAT3 localization and transcriptional activity via reciprocal STAT3 deacetylation at Lys685 and phosphorylation at Tyr705. In vivo, leptin sensitivity is substantially impaired in HDAC5 loss-of-function mice. Hypothalamic HDAC5 overexpression improves leptin action and partially protects against HFD-induced leptin resistance and obesity. Overall, our data suggest that hypothalamic HDAC5 activity is a regulator of leptin signalling that adapts food intake and body weight to our dietary environment.

Histone deacetylases (HDACs) regulate energy metabolism in peripheral tissues, but whether HDACs expressed in the brain influence systemic metabolism is unknown. Here the authors show that hypothalamic HDAC5 expression is affected by the diet and HDAC5 regulates leptin sensitivity by deacetylating STAT3.

Determinants of brain-derived neurotrophic factor (BDNF) in umbilical cord and maternal serum

OBJECTIVE

Brain-derived neurotrophic factor (BDNF) plays a fundamental role in brain development; additionally, it is involved in various aspects of cerebral function, including neurodegenerative and psychiatric diseases. Involvement of BDNF in parturition has not been investigated. The aim of our study was to analyze determinants of umbilical cord BDNF (UC-BDNF) concentrations of healthy, term newborns and their respective mothers.

METHODS

This cross-sectional prospective study was performed at a tertiary referral center. Maternal venous blood samples were taken on admission to labor ward; newborn venous blood samples were drawn from the umbilical cord (UC), before delivery of the placenta. Analysis was performed with a commercially available immunoassay. Univariate analyses and stepwise multivariate regression models were applied.

RESULTS

120 patients were recruited. UC-BDNF levels were lower than maternal serum concentrations (median 641 ng/mL, IQR 506 vs. median 780 ng/mL, IQR 602). Correlation between UC- and maternal BDNF was low (R=0.251, p=0.01). In univariate analysis, mode of delivery (MoD), gestational age (GA), body mass index at delivery, and gestational diabetes were determinants of UC-BDNF (MoD and smoking for maternal BDNF, respectively). Stepwise multivariate regression analysis revealed a model with MoD and GA as determinants for UC-BDNF (MoD for maternal BDNF).

CONCLUSIONS

MoD and GA at delivery are determinants of circulating BDNF in the mother and newborn. We hypothesize that BDNF, like other neuroendocrine factors, is involved in the neuroendocrine cascade of delivery. Timing and mode of delivery may exert BDNF-induced effects on the cerebral function of newborns and their mothers.

Mitochondrial ROS signaling in organismal homeostasis

Generation, transformation, and utilization of organic molecules in support of cellular differentiation, growth, and maintenance are basic tenets that define life. In eukaryotes, mitochondrial oxygen consumption plays a central role in these processes. During the process of oxidative phosphorylation, mitochondria utilize oxygen to generate ATP from organic fuel molecules but in the process also produce reactive oxygen species (ROS). While ROS have long been appreciated for their damage-promoting, detrimental effects, there is now a greater understanding of their roles as signaling molecules. Here, we review mitochondrial ROS-mediated signaling pathways with an emphasis on how they are involved in various basal and adaptive physiological responses that control organismal homeostasis.

The effect of delivery type on uncoupling protein-2 levels

OBJECTIVE

Uncoupling proteins (UCPs) are carrier proteins located in the mitochondrial inner membrane that disturb the proton gradient by re-transporting protons and that thus inhibit ATP synthesis. UCP-2 is found in in several tissues, particularly the brain. This study was performed to examine the effects of mode of delivery on UCP-2 in humans.

METHODS

The study was performed prospectively. Cord blood specimens were collected for measurement of blood gasses, full-blood count, total and direct bilirubin levels and UCP-2. UCP-2 levels were measured using an enzyme-linked immunosorbent assay (ELISA) kit. Results were expressed as nanogram per milliliter.

RESULTS

The study was performed with 120 healthy term babies, 60 born by normal spontaneous vaginal delivery (NSVD) and 60 by cesarean/section (C/S). There was significant difference in UCP-2 levels between the two groups. UCP-2 levels were significantly higher in the cases born by NSVD then in the cases born by C/S.

CONCLUSION

This study showed that a correlation exists between mode of delivery and UCP-2 in humans. As UCP-2 is described as playing a significant role in the formation of nerve cells and deficiency of this protein during development of the brain may lead to behavioral problems extending to adulthood, we think that increasing UCP-2 levels through normal delivery will protect all organs, and particularly the brain, against oxidative damage and play a role in preventing organ dysfunctions.

Social deficits induced by peripubertal stress in rats are reversed by resveratrol

Adolescence is increasingly recognized as a critical period for the development of the social system, through the maturation of social competences and of their underlying neural circuitries. The present study sought to test the utility of resveratrol, a dietary phenol recently reported to have mood lifting properties, in modulating social interaction that is deficient following early life adversity. The main aims were to 1) pharmacologically restore normative social investigation levels dampened by peripubertal stress in rats and 2) identify neural pathways engaged by this pharmacological approach. Following peripubertal (P28-42) stress consisting of unpredictable exposures to fearful experiences, at adulthood the subjects' propensity for social exploration was examined in the three-chamber apparatus, comparing time invested in social or non-social investigation. Administered intraperitoneally 30 min before testing, resveratrol (20 mg/kg) normalized the peripubertal stress-induced social investigation deficit seen in the vehicle group, selectively altering juvenile but not object exploration. Examination of prefrontal cortex subregion protein samples following acute resveratrol treatment in a separate cohort revealed that while monoamine oxidase A (MAOA) enzymatic activity remained unaltered, nuclear AKT activation was selectively increased in the infralimbic cortex, but not in the prelimbic or anterior cingulate cortex. In contrast, androgen receptor nuclear localization was increased in the prelimbic cortex, but not in the infralimbic or anterior cingulate cortex. This demonstration that social contact deficits are reversed by resveratrol administration emphasizes a prosocial role for this dietary phenol, and evokes the possibility of developing new treatments for social dysfunctions.

Neuroendocrinology of childbirth and mother-child attachment: the basis of an etiopathogenic model of perinatal neurobiological disorders

This review focuses on the neuroendocrine mechanisms in the mother and the newborn that are involved in the generation and consolidation of mother-child attachment. The role that different hormones and neurotransmitters play on the regulation of these mechanisms during parturition, the immediate postpartum period and lactation is discussed. Interferences in the initiation of mother-child attachment may have potential long-term effects for the behavior and affection of the newborn. Therefore, the possible consequences of alterations in the physiological neuroendocrine mechanisms of attachment, caused by elective Cesarean section, intrapartum hormonal manipulations, preterm delivery, mother-infant postpartum separation and bottle-feeding instead of breastfeeding are also discussed.

Perspectives on mitochondrial uncoupling proteins-mediated neuroprotection

The integrity of mitochondrial function is essential to cell life. It follows that disturbances of mitochondrial function will lead to disruption of cell function, expressed as disease or even death. Considering that neuronal uncoupling proteins (UCPs) decrease reactive oxygen species (ROS) production at the expense of energy production, it is important to understand the underlying mechanisms by which UCPs control the balance between the production of adenosine triphosphate (ATP) and ROS in the context of normal physiological activity and in pathological conditions. Here we review the current understanding of neuronal UCPs-mediated respiratory uncoupling process by performing a survey in their physiology and regulation. The latest findings regarding neuronal UCPs physiological roles and their involvement and interest as potential targets for therapeutic intervention in brain diseases will also be exploited.

Potential toxicity of quercetin: The repression of mitochondrial copy number via decreased POLG expression and excessive TFAM expression in irradiated murine bone marrow

The cytotoxicity of quercetin is not well understood. Using an ICR murine model, we unexpectedly found that mice exposed to 7 Gy total body irradiation (TBI) exhibited general in vivo toxicity after receiving quercetin (100 mg/kg PO), whereas this result was not observed in mice that received TBI only. In order to understand the involvement of alterations in mitochondrial biogenesis, we used a real-time qPCR to analyze the mitochondrial DNA copy number (mtDNAcn) by amplifying the MTRNR1 (12S rRNA) gene in murine bone marrow. We also utilized reverse transcription qPCR to determine the mRNA amounts transcribed from the polymerase gamma (POLG), POLG2, and mammalian mitochondrial transcription factor A (TFAM) genes in the tissue. In the mice exposed to TBI combined with quercetin, we found: (1) the radiation-induced increase of mtDNAcn was inhibited with a concurrent significant decrease in POLG expression; (2) TFAM expression was significantly increased; and (3) the expression of POLG2 was not influenced by the treatments. These data suggest that the overall toxicity was in part associated with the decrease in mtDNAcn, an effect apparently caused by the inhibition of POLG expression and overexpression of TFAM; unaltered POLG2 expression did not seem to contribute to toxicity.

Hippocampal UCP2 is essential for cognition and resistance to anxiety but not required for the benefits of exercise

Uncoupling protein-2 (UCP2) reduces oxidative stress by facilitating the influx of protons into mitochondrial matrix, thus dissociating mitochondrial oxidation from ATP synthesis. UCP2 is expressed abundantly in brain areas and plays a key role in neuroprotection. Here, we sought to determine if UCP2 deficiency produces cognitive impairment and anxiety in young mice, and to determine if hippocampal UCP2 is essential for the beneficial effects of voluntary exercise. Antisense oligonucleotide (ASO) was used to produce UCP2 knockdown in mice. Our results firstly showed that UCP2-targeted ASO significantly reduced UCP2 mRNA and protein expression in the hippocampus. ASO treatment impaired learning and memory of the mice in Y-maze, T-maze, and object recognition tests (ORT). ASO-treated mice exhibited more anxiously in OPT, light/dark box test, and elevated plus maze (EPM) than the control mice. We also found that wheel running ameliorated cognitive dysfunction and anxiety-like behaviors in ASO-treated mice. Furthermore, voluntary exercise reversed ASO-induced changes in hippocampal levels of serotonin (5-HT), dopamine (DA), and norepinephrine (NE). However, UCP2 protein in the hippocampus was not correlated with cognitive and anxiolytic benefits of exercise. These findings suggest that hippocampal UCP2 is essential for cognitive function and the resistance to anxiety of mice, but not required for the beneficial effects of exercise.

UCP2, a mitochondrial protein regulated at multiple levels

An ever-increasing number of studies highlight the role of uncoupling protein 2 (UCP2) in a broad range of physiological and pathological processes. The knowledge of the molecular mechanisms of UCP2 regulation is becoming fundamental in both the comprehension of UCP2-related physiological events and the identification of novel therapeutic strategies based on UCP2 modulation. The study of UCP2 regulation is a fast-moving field. Recently, several research groups have made a great effort to thoroughly understand the various molecular mechanisms at the basis of UCP2 regulation. In this review, we describe novel findings concerning events that can occur in a concerted manner at various levels: Ucp2 gene mutation (single nucleotide polymorphisms), UCP2 mRNA and protein expression (transcriptional, translational, and protein turn-over regulation), UCP2 proton conductance (ligands and post-transcriptional modifications), and nutritional and pharmacological regulation of UCP2.

Uncoupling protein 2 and 4 expression pattern during stem cell differentiation provides new insight into their putative function

Apart from the first family member, uncoupling protein 1 (UCP1), the functions of other UCPs (UCP2-UCP5) are still unknown. In analyzing our own results and those previously published by others, we have assumed that UCP's cellular expression pattern coincides with a specific cell metabolism and changes if the latter is altered. To verify this hypothesis, we analyzed the expression of UCP1-5 in mouse embryonic stem cells before and after their differentiation to neurons. We have shown that only UCP2 is present in undifferentiated stem cells and it disappears simultaneously with the initiation of neuronal differentiation. In contrast, UCP4 is simultaneously up-regulated together with typical neuronal marker proteins TUJ-1 and NeuN during mESC differentiation in vitro as well as during murine brain development in vivo. Notably, several tested cell lines express UCP2, but not UCP4. In line with this finding, neuroblastoma cells that display metabolic features of tumor cells express UCP2, but not UCP4. UCP2's occurrence in cancer, immunological and stem cells indicates that UCP2 is present in cells with highly proliferative potential, which have a glycolytic type of metabolism as a common feature, whereas UCP4 is strongly associated with non-proliferative highly differentiated neuronal cells.

Natural birth-induced UCP2 in brain development

The prevalence of convenience-driven delivery via Caesarian-section (C-section) has been steadily increasing in Western as well as in developing societies. Today, significantly more deliveries occur via surgical means than medical necessity mandates. Despite tremendous advances in surgical techniques and pre- and post-operative surgical care, there remains to be limited understanding on the physiological influence of vaginal birth with particular emphasis on long term outcome on the offspring. Serendipitously, we recently uncovered in mice that vaginal birth induces significantly higher level of Ucp2 mRNA expression in the hippocampus than experimental C-section. We showed that during the early postnatal period, UCP2 expression promotes neuronal differentiation, axonal outgrowth and synapse formation in the hippocampus. We also observed that Ucp2 knockout animals show adult behaviors associated with the hippocampal formation that is different from wild type littermates. Taken together these observations suggest that vaginal birth may play a crucial role in determining adult brain structure and function that is different from that of the effect of surgically assisted birth.

Mode of delivery may influence neonatal responsiveness to maternal separation

INTRODUCTION

Maternal-infant separation (MIS) is a highly stressful situation for the neonate.

MATERIALS AND METHODS

A study was conducted to observe and describe the reactions of term neonates to brief maternal separation and restoration of skin contact within the first 48 h of life, and to assess whether the mode of delivery influences neonatal responsiveness. A brief maternal-infant separation situation was videotaped to observe the reactions of the newborns within the first 12-48 h of life. Characteristics observed in the newborns were: the Moro reflex, spreading out arms and feet, looking at the mother, presence/lack of crying, and some dichotomous variables (present or lacking); in mothers: adult speech, "motherese" speech, speaking to another adult present in the room, singing, clicking, tapping on the diaper, rocking, kissing the baby, touching toes, touching hands, changing position, making loving comments, calling the newborn by his/her name and touching his/her back. Crying on restoration of contact was measured.

RESULTS

Ten neonates born by planned C-section and 21 neonates born by oxytocin-induced vaginal delivery were included. No behavioral differences were observed according to the mode of delivery. Neonates born by vaginal delivery took longer (64.8±8.6 s) to calm down than those born by C-section (0.9±1.4 s) (p=0.004). A correlation was observed between cortisol concentrations at birth and the time required to calm the baby down (r=0.41; p=0.02).

CONCLUSION

Neonates born by a planned C-section cried much less on maternal separation, which might indicate an altered attachment behavior and altered response to stress. Further studies are needed to determine the potential long-term implications of variations in mother-infant attachment during the first days of life.

Neurogenesis continues in the third trimester of pregnancy and is suppressed by premature birth

Premature infants exhibit neurodevelopmental delay and reduced growth of the cerebral cortex. However, the underlying mechanisms have remained elusive. Therefore, we hypothesized that neurogenesis in the ventricular and subventricular zones of the cerebral cortex would continue in the third trimester of pregnancy and that preterm birth would suppress neurogenesis. To test our hypotheses, we evaluated autopsy materials from human fetuses and preterm infants of 16-35 gestational weeks (gw). We noted that both cycling and noncycling Sox2(+) radial glial cells and Tbr2(+) intermediate progenitors were abundant in human preterm infants until 28 gw. However, their densities consistently decreased from 16 through 28 gw. To determine the effect of premature birth on neurogenesis, we used a rabbit model and compared preterm [embryonic day 29 (E29), 3 d old] and term (E32, <2 h old) pups at an equivalent postconceptional age. Glutamatergic neurogenesis was suppressed in preterm rabbits, as indicated by the reduced number of Tbr2(+) intermediate progenitors and the increased number of Sox2(+) radial glia. Additionally, hypoxia-inducible factor-1α, vascular endothelial growth factor, and erythropoietin were higher in term than preterm pups, reflecting the hypoxic intrauterine environment of just-born term pups. Proneural genes, including Pax6 and Neurogenin-1 and -2, were higher in preterm rabbit pups compared with term pups. Importantly, neurogenesis and associated factors were restored in preterm pups by treatment with dimethyloxallyl glycine, a hypoxia mimetic agent. Hence, glutamatergic neurogenesis continues in the premature infants, preterm birth suppresses neurogenesis, and hypoxia-mimetic agents might restore neurogenesis, enhance cortical growth, and improve neurodevelopmental outcome of premature infants.