Mental health and cerebellar volume during adolescence in very-low-birth-weight infants: a longitudinal study

Multidisciplinary and neuroimaging findings in preterm born very low birthweight individuals from birth to 28 years of age: A systematic review of a Norwegian prospective cohort study

BACKGROUND

Children born preterm with very low birthweight (VLBW) face long-lasting neurodevelopmental challenges, where multidisciplinary assessments are warranted. The International Classification of Functioning, Disability and Health (ICF) provides a framework for understanding and conceptualising these outcomes.

OBJECTIVES

We aimed to review clinical and neuroimaging findings from birth to adulthood in a Norwegian cohort of individuals born preterm with VLBW (gestational age <37 weeks, birthweight ≤1500 g) within the framework of ICF.

DATA SOURCES

We searched PubMed and Embase for articles reporting results of the Norwegian University of Science and Technology (NTNU) Low Birth Weight in a Lifetime Perspective study.

STUDY SELECTION AND DATA EXTRACTION

We included original articles reporting proportions of adverse outcomes, mean group differences, risk factors or associations between outcomes. Data were extracted according to ICF's two-level classification. Body functions and structures comprised outcomes of brain structures, cognition, mental health, vision, pain and physical health. Activities and participation comprised motor skills, general and social functioning, education, employment, and health-related quality of life.

SYNTHESIS

We performed a qualitative synthesis of included articles. Where mean (SD) was reported, we calculated group differences in SD units.

RESULTS

Fifty-eight publications were included. Within body functions and structures, increased prevalence of brain structure pathology, lower cognitive performance, mental health problems, visual and physical health impairments through childhood, adolescence and young adulthood were reported among preterm VLBW participants compared with controls. Within activities and participation, motor problems, lower general and social functioning, and lower academic attainment were found. Perinatal factors were associated with several outcomes, and longitudinal findings suggested persistent consequences of being born preterm with VLBW.

CONCLUSIONS

Being born preterm with VLBW has long-term influences on body functions and structures, activities and participation. The ICF is appropriate for assessing general domains of functioning and guiding the management of individuals born preterm with VLBW.

A unique cerebellar pattern of microglia activation in a mouse model of encephalopathy of prematurity

Preterm infants often show pathologies of the cerebellum, which are associated with impaired motor performance, lower IQ and poor language skills at school ages. Using a mouse model of inflammation-induced encephalopathy of prematurity driven by systemic administration of pro-inflammatory IL-1β, we sought to uncover causes of cerebellar damage. In this model, IL-1β is administered between postnatal day (P) 1 to day 5, a timing equivalent to the last trimester for brain development in humans. Structural MRI analysis revealed that systemic IL-1β treatment induced specific reductions in gray and white matter volumes of the mouse cerebellar lobules I and II (5% false discovery rate [FDR]) from P15 onwards. Preceding these MRI-detectable cerebellar volume changes, we observed damage to oligodendroglia, with reduced proliferation of OLIG2+ cells at P10 and reduced levels of the myelin proteins myelin basic protein (MBP) and myelin-associated glycoprotein (MAG) at P10 and P15. Increased density of IBA1+ cerebellar microglia were observed both at P5 and P45, with evidence for increased microglial proliferation at P5 and P10. Comparison of the transcriptome of microglia isolated from P5 cerebellums and cerebrums revealed significant enrichment of pro-inflammatory markers in microglia from both regions, but cerebellar microglia displayed a unique type I interferon signaling dysregulation. Collectively, these data suggest that perinatal inflammation driven by systemic IL-1β leads to specific cerebellar volume deficits, which likely reflect oligodendrocyte pathology downstream of microglial activation. Further studies are now required to confirm the potential of protective strategies aimed at preventing sustained type I interferon signaling driven by cerebellar microglia as an important therapeutic target.

Impaired Cell Cycle Progression and Self-Renewal of Fetal Neural Stem and Progenitor Cells in a Murine Model of Intrauterine Growth Restriction

Individuals with intrauterine growth restriction (IUGR) are at an increased risk for neurodevelopmental impairment. Fetal cortical neurogenesis is a time-sensitive process in which fetal neural stem cells (NSCs) follow a distinct pattern of layer-specific neuron generation to populate the cerebral cortex. Here, we used a murine maternal hypoxia-induced IUGR model to study the impact of IUGR on fetal NSC development. In this model, timed-pregnant mice were exposed to hypoxia during the active stage of neurogenesis, followed by fetal brain collection and analysis. In the IUGR fetal brains, we found a significant reduction in cerebral cortical thickness accompanied by decreases in layer-specific neurons. Using EdU labeling, we demonstrated that cell cycle progression of fetal NSCs was delayed, primarily observed in the G2/M phase during inward interkinetic nuclear migration. Following relief from maternal hypoxia exposure, the remaining fetal NSCs re-established their neurogenic ability and resumed production of layer-specific neurons. Surprisingly, the newly generated neurons matched their control counterparts in layer-specific marker expression, suggesting preservation of the fetal NSC temporal identity despite IUGR effects. As expected, the absolute number of neurons generated in the IUGR group remained lower compared to that in the control group due to a reduced fetal NSC pool size as a result of cell cycle defect. Transcriptome analysis identified genes related to energy expenditure and G2/M cell cycle progression being affected by maternal hypoxia-induced IUGR. Taken together, maternal hypoxia-induced IUGR is associated with a defect in cell cycle progression of fetal NSCs, and has a long-term impact on offspring cognitive development.

Neurobehavioral Phenotype and Dysexecutive Syndrome of Preterm Children: Comorbidity or Trigger? An Update

Premature birth is a worldwide public health priority. One in ten children is born before 37 weeks of gestational age and, in developed countries, survival rates without major neonatal morbidity are increasing. Although severe sequelae associated with these births have decreased, their neurobehavioral difficulties, often associated in multiple fields, remain stable but still widespread. These neurobehavioral difficulties hamper the normal development of academic achievements and societal integration and intensify the children's needs for rehabilitation during their preschool and academic years. Severe sequelae increase when gestational age decreases. This is even truer if the socio-cultural background is impeded by low income, education and language skills as compared with defined averages. However, moderate and/or minor neurocognitive and/or behavioral difficulties are almost identical for a moderate or a late preterm birth. Obtaining a better clinical description of neurobehavioral characteristics of those pretermly born, once they reach preschool age, is essential to detect behavioral issues as well as early specific cognitive difficulties (working memory, planning, inhibition, language expression and reception, attention and fine motor skills, etc.). Such information would provide a better understanding of the executive functions' role in brain connectivity, neurodevelopment and neuroanatomical correlation with premature encephalopathy.

Disruption of neonatal Purkinje cell function underlies injury-related learning deficits

Injury to the cerebellum during late fetal and early postnatal life is associated with long-term motor and cognitive deficits. It is thought that injury at this stage of development results in delayed maturation of neural circuitry, causing altered behavior at later stages. This study identifies the neural basis of locomotor learning deficits in the cerebellum using a clinically relevant model of neonatal brain injury. By combining fiber-optic-enabled Purkinje cell activity measurement during locomotor behavior, we provide evidence for long-term changes in neuronal responses during learning. By artificially reducing Purkinje cell function during the neonatal stage, we observed similarly altered physiological responses as those seen in injury. Our findings indicate that injury-related inhibition of developing Purkinje cells causes long-term locomotor dysfunction.

It is hypothesized that perinatal cerebellar injury leads to long-term functional deficits due to circuit dysmaturation. Using a novel integration of GCaMP6f fiber photometry with automated measurement of cerebellar behavior using the ErasmusLadder, we causally link cerebellar injury to altered Purkinje cell responses during maladaptive behavior. Chemogenetic inhibition of neonatal Purkinje cells is sufficient to phenocopy the effects of perinatal cerebellar injury. Our results uncover a direct link between perinatal cerebellar injury and activity-dependent maturation of cerebellar cortex.

Inflammatory predictors of neurobehavior in very preterm infants

BACKGROUND

Preterm infants are at risk for impaired neurodevelopment. Inflammation may be an important modifiable mediator of preterm birth and neurodevelopmental impairment, but few studies have examined longitudinal measures of inflammation.

OBJECTIVE

To determine the relationship between longitudinal measures of inflammation and neurobehavior in very preterm infants.

STUDY DESIGN

Non-experimental, repeated measures cohort study.

METHODS

Very preterm infants were enrolled between October 2017 and December 2018. Blood was collected weekly until 35 weeks post-menstrual age for the quantification of plasma cytokines. Neurobehavior was assessed at 35 weeks post-menstrual age using the cluster scores for motor development and vigor and alertness/orientation from the Neurobehavioral Assessment of the Preterm Infant. Multiple linear regression models with robust standard errors were used to analyze the data. Average levels of individual cytokines, cytokine trends, and composite scores were used as measures of inflammation.

RESULTS

Seventy-three infants were enrolled in the study. Interleukin-1 receptor antagonist was associated with motor development and vigor scores. Interleukin-6 was associated with alertness/orientation scores. Tumor necrosis factor-alpha and composite scores of inflammation were associated with motor development and vigor and alertness/orientation scores. There were interactions with post-menstrual age at birth and infant sex.

CONCLUSION

Inflammation may be an important predictor of short-term neurobehavior in preterm infants. Interleukin-1 receptor antagonist, interleukin-6, and tumor necrosis factor-alpha are key cytokines for studies of preterm infants, but composite scores may be a better measure of inflammation than individual cytokines. Inflammation can be damaging to the immature brain and may be a specific target for future interventions to improve outcomes.

Assessment of social factors influencing hospitalization cost of US preterm newborns, 2016

Background and objective: Preterm newborn (PTN) care is costly in the US, and the preterm birth (PTB) rate has not seen substantial improvement. PTB remains a significant public health issue because of risks of adverse health outcomes and the associated economic burden. Assessing factors leading to high hospital cost is imperative in order to ease economic burden associated with PTB. Social factors influencing hospitalization cost for PTN have not been studied extensively. This study aims to examine the contributions of hospital type, race/ethnicity, and median household income quartile to the cost of the PTN's initial hospitalization after birth.Materials and methods: Data used in this study originated from the 2016 Healthcare Cost and Utilization Project Kids' Inpatient Database (KID) which provided the most recent national records of pediatric hospitalization in the US. International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes P07.2x and P07.3x were used to identify birth gestational age (GA) in complete weeks. Q00-Q99 codes were used to identify congenital anomalies. Data records reflecting hospitalization of newborns without congenital anomalies were extracted to estimate total cost in 2016. Analysis of factors influencing total cost was performed on the subset of newborns that were in-born and with birth GA from 24 to 36 weeks. Total hospital cost was calculated by multiplying total charges and cost-to-charge ratios. Per-diem cost was calculated by dividing total hospital cost by length of stay. Linear regression modeling was performed using weighted data, and the best model was selected using the Akaike information criteria. Results: Hospitalization cost for PTNs, who constituted 7.6% of all studied newborns, comprised 45% of total newborn hospitalization cost. PTNs in freestanding children's hospitals had significantly higher total cost compared to non-children's teaching and non-teaching hospitals. The cost difference was GA-dependent. The latter two hospital types reported similar cost for PTNs. Although race/ethnicity and median household income quartile were related, the two covariates had independent effects on total hospitalization cost. A model built to assess the roles of covariates in the association between GA and total hospitalization cost found that all three covariates independently affected total cost when controlling for one another, with hospital type also showing an interaction effect with GA.Conclusions: Hospitalization cost is highly influenced by hospital type, race/ethnicity, and median household income quartile. The modifiable aspects of these factors may be further dissected and targeted in order to ease the burden of high hospitalization cost associated with PTB.

Brain volumes in relation to loneliness and social competence in preadolescents born very preterm

INTRODUCTION

The aim of the present study was to assess how regional brain volumes associate with self-experienced social and emotional loneliness and social competence in very preterm and term-born preadolescents.

MATERIALS AND METHODS

Thirty-four very preterm subjects (birthweight ≤1,500 g and/or gestational age <32 weeks) without neurodevelopmental impairments and/or major brain pathologies and 31 term-born subjects underwent magnetic resonance imaging at 12 years of age. Regional brain volumes were measured using an automated image quantification tool. At 11 years of age, social and emotional loneliness were assessed with the Peer Network and Dyadic Loneliness Scale-self-report questionnaire and cooperating skills, empathy, impulsivity, and disruptiveness with the Multisource Assessment of Children's Social Competence Scale-self-report questionnaire.

RESULTS

In the very preterm group, a number of significant associations were found between smaller regional brain volumes and self-experienced emotional loneliness, more impulsivity and more disruptiveness. In the control group, brain volumes and loneliness were not associated, and brain volumes and social competence were associated with a lesser degree than in the very preterm group.

CONCLUSION

Experiences of emotional loneliness and poorer social competence appear to be more related to brain volumes in very preterm preadolescents than in those born full-term. It also appears that in very preterm preadolescents, emotional loneliness may be more reflected in brain development than social loneliness.

Subtypes of behavioral functioning in 8-12 year old very preterm children

BACKGROUND

Very preterm children often have difficulties in behavioral functioning, but there is large heterogeneity in the severity of these difficulties and in the combination of the difficulties observed. Few studies so far addressed this heterogeneity by examining whether more homogeneous subtypes of behavioral functioning can be identified.

AIMS

To identify behavioral subtypes in a group of very preterm children, examine whether such subtypes are related to neonatal medical complications and/or parental education level (to better understand origins) and to examine whether such subtypes are associated with IQ and neurocognitive deficits in attention and executive function (to study underlying mechanisms of dysfunction).

STUDY DESIGN

Cross-sectional cohort study.

SUBJECTS

135 very preterm (gestational age < 30 weeks and/or birthweight < 1000 g) children aged 8-12 years.

MEASURES

Parent and teacher questionnaires covering a broad range of behavioral domains, parental education level, neonatal medical complications, short-form Wechsler Intelligence Scale for Children-III and performance-based attention and executive function measures.

RESULTS

Cluster analysis indicated two behavioral subtypes: a subtype characterized by low behavioral problems (76% of children) and a subtype characterized by high behavioral problems across behavioral domains (24% of children). Lower parental education level, lower IQ and poorer verbal working memory, visuospatial working memory and inhibition were associated with the high problems subtype, but neonatal medical complications were not.

CONCLUSIONS

The majority of very preterm children was assigned to the low behavioral problems subtype. However, if problems do occur, they are wide-spread across behavioral domains and accompanied by problems in neurocognitive domains.

Glial Factors Regulating White Matter Development and Pathologies of the Cerebellum

The cerebellum is a brain region that undergoes extremely dynamic growth during perinatal and postnatal development which is regulated by the proper interaction between glial cells and neurons with a complex concert of growth factors, chemokines, cytokines, neurotransmitters and transcriptions factors. The relevance of cerebellar functions for not only motor performance but also for cognition, emotion, memory and attention is increasingly being recognized and acknowledged. Since perturbed circuitry of cerebro-cerebellar trajectories can play a role in many central nervous system pathologies and thereby contribute to neurological symptoms in distinct neurodevelopmental and neurodegenerative diseases, is it the aim with this mini-review to highlight the pathways of glia–glia interplay being involved. The designs of future treatment strategies may hence be targeted to molecular pathways also playing a role in development and disease of the cerebellum.

The SLC25A42 Transcript Is a Biomarker for Fetal Reprogramming in Response to Placental Insufficiency in Preterm Newborns Under 32 Weeks Gestation-A Pilot Study

Introduction: Timing of medical delivery of preterm newborns exposed to placental insufficiency is largely determined by umbilical artery blood flow and maternal clinical manifestations. There is a lack of tools to properly assess fetal body response to placental insufficiency before or upon delivery. Yet, short- and long-term comorbidities associated with placental insufficiency and the consequential intrauterine growth restriction may be a result of fetal response following prolonged stress. This study aims to establish a procedure to investigate fetal/neonatal transcriptional response to placental insufficiency as part of an initiative to identify cost-effective biomarkers for assessing fetal response to placental insufficiency. Methods: A prospective pilot study involving newborns with birth gestation <32 weeks was conducted to compare gene expression profiles in whole blood collected at birth among three clinically distinct groups - preeclampsia without placental insufficiency (PE), placental insufficiency (PI), and non-PE/PI groups. Results: Whole blood from 11, 3, and 6 newborns in the non-PE/PI, PE, and PI groups were obtained. A transcriptome analysis found that the majority of the genes were downregulated in the PI group, suggesting global transcriptional inactivation. Intriguingly, SLC25A42, which encodes a mitochondrial transporter for coenzyme A and adenosine-3',5'-diphosphate, was significantly upregulated in the PI group. Conclusion: Transcriptional biomarkers for assessing fetal response to placental insufficiency may provide a useful tool to better understand the pathophysiology of fetal reprogramming in response to placental insufficiency. The validity and the role of SLC25A42, as well as its correlation with short- and long-term neonatal outcomes, warrants further investigation.

Prenatal cerebellar growth trajectories and the impact of periconceptional maternal and fetal factors

STUDY QUESTION

CAN WE assess human prenatal cerebellar growth from the first until the third trimester of pregnancy and create growth trajectories to investigate associations with periconceptional maternal and fetal characteristics?

SUMMARY ANSWER

Prenatal growth trajectories of the human cerebellum between 9 and 32 weeks gestational age (GA) were created using three-dimensional ultrasound (3D-US) and show negative associations with pre-pregnancy and early first trimester BMI calculated from self-reported and standardized measured weight and height, respectively.

WHAT IS KNOWN ALREADY

The cerebellum is essential for normal neurodevelopment and abnormal cerebellar development has been associated with neurodevelopmental impairments and psychiatric diseases. Cerebellar development is particularly susceptible to exposures during the prenatal period, including maternal folate status, smoking habit and alcohol consumption.

STUDY DESIGN, SIZE, DURATION

From 2013 until 2015, we included 182 singleton pregnancies during the first trimester as a subgroup in a prospective periconception cohort with follow-up until birth. For the statistical analyses, we selected 166 pregnancies ending in live born infants without congenital malformations.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We measured transcerebellar diameter (TCD) at 9, 11, 22, 26 and 32 weeks GA on ultrasound scans. Growth rates were calculated and growth trajectories of the cerebellum were created. Linear mixed models were used to estimate associations between cerebellar growth and maternal age, parity, mode of conception, geographic origin, pre-pregnancy and first trimester BMI, periconceptional smoking, alcohol consumption, timing of folic acid supplement initiation and fetal gender.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 166 pregnancies provided 652 (87%) ultrasound images eligible for TCD measurements. Cerebellar growth rates increased with advancing GA being 0.1691 mm/day in the first trimester, 0.2336 mm/day in the second trimester and 0.2702 mm/day in the third trimester. Pre-pregnancy BMI, calculated from self-reported body weight and height, was significantly associated with decreased cerebellar growth trajectories (β = -0.0331 mm, 95% CI = -0.0638; -0.0024, P = 0.035). A similar association was found between cerebellar growth trajectories and first trimester BMI, calculated from standardized measurements of body weight and height (β = -0.0325, 95% CI = -0.0642; -0.0008, P = 0.045, respectively).

LIMITATIONS, REASONS FOR CAUTION

As the study population largely consisted of tertiary hospital patients, external validity should be studied in the general population. Whether small differences in prenatal cerebellar growth due to a higher pre-pregnancy and first trimester BMI have consequences for neurodevelopmental outcome needs further investigation.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings further substantiate previous evidence for the detrimental impact of a higher maternal BMI on neurodevelopmental health of offspring in later life.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the Department of Obstetrics and Gynecology, Erasmus MC University Medical Centre and Sophia Children's Hospital Fund, Rotterdam, The Netherlands (SSWO grant number 644). No competing interests are declared.

Involvement of Noncoding RNAs in Stress-Related Neuropsychiatric Diseases Caused by DOHaD Theory : ncRNAs and DOHaD-Induced Neuropsychiatric Diseases

According to the DOHaD theory, low birth weight is a risk factor for various noncommunicable chronic diseases that develop later in life. Noncoding RNAs (ncRNAs), including miRNAs, siRNAs, piRNAs, and lncRNAs, are functional RNA molecules that are transcribed from DNA but that are not translated into proteins. In general, miRNAs, siRNAs, and piRNAs function to regulate gene expression at the transcriptional and posttranscriptional levels. Studying ncRNAs has provided opportunities for new diagnosis and therapeutic knowledge in the endocrinological and metabolic fields as well as cancer biology. In this review, we focus on the roles of miRNAs and lncRNAs in the pathophysiology of stress-related neuropsychiatric diseases, which show abnormal blood hormone levels due to loss of feedback control and/or decreased sensitivity. Numerous recent studies have begun to unveil the importance of ncRNAs in regulation of stress-related hormone levels and functions. We summarize the involvement of abnormal ncRNA expression in the development of stress-related neuropsychiatric diseases based on the DOHaD theory.

A longitudinal study of associations between psychiatric symptoms and disorders and cerebral gray matter volumes in adolescents born very preterm

Background

Being born preterm with very low birthweight (VLBW ≤ 1500 g) poses a risk for cortical and subcortical gray matter (GM) abnormalities, as well as for having more psychiatric problems during childhood and adolescence than term-born individuals. The aim of this study was to investigate the relationship between cortical and subcortical GM volumes and the course of psychiatric disorders during adolescence in VLBW individuals.

Methods

We followed VLBW individuals and term-born controls (birth weight ≥10th percentile) from 15 (VLBW;controls n = 40;56) to 19 (n = 44;60) years of age. Of these, 30;37 individuals were examined longitudinally. Cortical and subcortical GM volumes were extracted from MRPRAGE images obtained with the same 1.5 T MRI scanner at both time points and analyzed at each time point with the longitudinal stream of the FreeSurfer software package 5.3.0. All participants underwent clinical interviews and were assessed for psychiatric symptoms and diagnosis (Schedule for Affective Disorders and Schizophrenia for School-age Children, Children’s Global Assessment Scale, Attention-Deficit/Hyperactivity Disorder Rating Scale-IV). VLBW adolescents were divided into two groups according to diagnostic status from 15 to 19 years of age: persisting/developing psychiatric diagnosis or healthy/becoming healthy.

Results

Reduction in subcortical GM volume at 15 and 19 years, not including the thalamus, was limited to VLBW adolescents with persisting/developing diagnosis during adolescence, whereas VLBW adolescents in the healthy/becoming healthy group had similar subcortical GM volumes to controls. Moreover, across the entire VLBW group, poorer psychosocial functioning was predicted by smaller subcortical GM volumes at both time points and with reduced GM volume in the thalamus and the parietal and occipital cortex at 15 years. Inattention problems were predicted by smaller GM volumes in the parietal and occipital cortex.

Conclusions

GM volume reductions in the parietal and occipital cortex as well as smaller thalamic and subcortical GM volumes were associated with the higher rates of psychiatric symptoms found across the entire VLBW group. Significantly smaller subcortical GM volumes in VLBW individuals compared with term-born peers might pose a risk for developing and maintaining psychiatric diagnoses during adolescence. Future research should explore the possible role of reduced cortical and subcortical GM volumes in the pathogenesis of psychiatric illness in VLBW adolescents.

Electronic supplementary material

The online version of this article (doi:10.1186/s12887-017-0793-0) contains supplementary material, which is available to authorized users.