Brain disorders associated with corticotropin-releasing hormone expression in the placenta among children born before the 28th week of gestation

Sex-specific associations between placental corticotropin releasing hormone and problem behaviors in childhood

Placental corticotropin-releasing hormone (pCRH) is a neuroactive peptide produced in high concentrations in mid-late pregnancy, during key periods of fetal brain development. Some evidence suggests that higher pCRH exposure during gestation is associated with adverse neurodevelopment, particularly in female offspring. In 858 mother-child dyads from the sociodemographically diverse CANDLE cohort (Memphis, TN), we examined: (1) the slope of pCRH rise in mid-late pregnancy and (2) estimated pCRH at delivery as a measure of cumulative prenatal exposure. When children were 4 years-old, mothers reported on problem behaviors using the Child Behavior Checklist (CBCL) and cognitive performance was assessed by trained psychologists using the Stanford-Binet Intelligence Scales. We fitted linear regression models examining pCRH in relation to behavioral and cognitive performance measures, adjusting for covariates. Using interaction models, we evaluated whether associations differed by fetal sex, breastfeeding, and postnatal neighborhood opportunity. In the full cohort, log-transformed pCRH measures were not associated with outcomes; however, we observed sex differences in some models (interaction p-values≤0.01). In male offspring, an interquartile (IQR) increase in pCRH slope (but not estimated pCRH at delivery), was positively associated with raw Total (β=3.06, 95%CI: 0.40, 5.72), Internalizing (β=0.89, 95%CI: 0.03, 1.76), and Externalizing (β=1.25, 95%CI: 0.27, 2.22) Problem scores, whereas, in females, all associations were negative (Total Problems: β=-1.99, 95%CI: -3.89, -0.09; Internalizing: β=-0.82, 95%CI: -1.42, -0.23; Externalizing: β=-0.56, 95%CI: -1.34, 0.22). No associations with cognitive performance were observed nor did we observe moderation by breastfeeding or postnatal neighborhood opportunity. Our results provide further evidence that prenatal pCRH exposure may impact subsequent child behavior in sex-specific ways, however in contrast to prior studies suggesting adverse impacts in females, steeper mid-gestation pCRH rise was associated with more problem behaviors in males, but fewer in females.

Brain Damage in Preterm and Full-Term Neonates: Serum Biomarkers for the Early Diagnosis and Intervention

The Brain is vulnerable to numerous insults that can act in the pre-, peri-, and post-natal period. There is growing evidence that demonstrate how oxidative stress (OS) could represent the final common pathway of all these insults. Fetuses and newborns are particularly vulnerable to OS due to their inability to active the antioxidant defenses. Specific molecules involved in OS could be measured in biologic fluids as early biomarkers of neonatal brain injury with an essential role in neuroprotection. Although S-100B seems to be the most studied biomarker, its use in clinical practice is limited by the complexity of brain damage etiopathogenesis and the time of blood sampling in relation to the brain injury. Reliable early specific serum markers are currently lacking in clinical practice. It is essential to determine if there are specific biomarkers that can help caregivers to monitor the progression of the disease in order to active an early neuroprotective strategy. We aimed to describe, in an educational review, the actual evidence on serum biomarkers for the early identification of newborns at a high risk of neurological diseases. To move the biomarkers from the bench to the bedside, the assays must be not only be of a high sensitivity but suitable for the very rapid processing and return of the results for the clinical practice to act on. For the best prognosis, more studies should focus on the association of these biomarkers to the type and severity of perinatal brain damage.

Genome-Wide Copy Number Variant and High-Throughput Transcriptomics Analyses of Placental Tissues Underscore Persisting Child Susceptibility in At-Risk Pregnancies Cleared in Standard Genetic Testing

Several studies have shown that children from pregnancies with estimated first-trimester risk based on fetal nuchal translucency thickness and abnormal maternal serum pregnancy protein and hormone levels maintain a higher likelihood of adverse outcomes, even if initial testing for known genetic conditions is negative. We used the Finnish InTraUterine cohort (ITU), which is a comprehensively characterized perinatal cohort consisting of 943 mothers and their babies followed throughout pregnancy and 18 months postnatally, including mothers shortlisted for prenatal genetic testing but cleared for major aneuploidies (cases: n = 544, 57.7%) and control pregnancies (n = 399, 42.3%). Using genome-wide genotyping and RNA sequencing of first-trimester and term placental tissue, combined with medical information from registry data and maternal self-report data, we investigated potential negative medical outcomes and genetic susceptibility to disease and their correlates in placenta gene expression. Case mothers did not present with higher levels of depression, perceived stress, or anxiety during pregnancy. Case children were significantly diagnosed more often with congenital malformations of the circulatory system (4.12 (95% CI [1.22−13.93]) higher hazard) and presented with significantly more copy number duplications as compared to controls (burden analysis, based on all copy number variants (CNVs) with at most 10% frequency, 823 called duplications in 297 cases versus 626 called duplications in 277 controls, p = 0.01). Fifteen genes showed differential gene expression (FDR < 0.1) in association with congenital malformations in first-trimester but not term placenta. These were significantly enriched for genes associated with placental dysfunction. In spite of normal routine follow-up prenatal testing results in early pregnancy, case children presented with an increased likelihood of negative outcomes, which should prompt vigilance in follow-up during pregnancy and after birth.

Placental pathology: Pathways leading to or associated with perinatal brain injury in experimental neurology, special issue: Placental mediated mechanisms of perinatal brain injury

Perinatal brain injury is a multifactorial process. In utero placental physiology plays a major role in neuroprotection and the normal development of the fetal central nervous system. Advances in placental pathology have clarified several specific mechanisms of injury and the histologic lesions most strongly associated with them. This review provides an updated summary of the relevant placental anatomy and physiology, the specific placental pathways leading to brain injury, the revised Amsterdam classification system for placental pathology, and the known associations of specific placental lesions with subtypes of adverse neurologic outcomes.

Placental CRH as a Signal of Pregnancy Adversity and Impact on Fetal Neurodevelopment

Early life is a period of considerable plasticity and vulnerability and insults during that period can disrupt the homeostatic equilibrium of the developing organism, resulting in adverse developmental programming and enhanced susceptibility to disease. Fetal exposure to prenatal stress can impede optimum brain development and deranged mother's hypothalamic-pituitary-adrenal axis (HPA axis) stress responses can alter the neurodevelopmental trajectories of the offspring. Corticotropin-releasing hormone (CRH) and glucocorticoids, regulate fetal neurogenesis and while CRH exerts neuroprotective actions, increased levels of stress hormones have been associated with fetal brain structural alterations such as reduced cortical volume, impoverishment of neuronal density in the limbic brain areas and alterations in neuronal circuitry, synaptic plasticity, neurotransmission and G-protein coupled receptor (GPCR) signalling. Emerging evidence highlight the role of epigenetic changes in fetal brain programming, as stress-induced methylation of genes encoding molecules that are implicated in HPA axis and major neurodevelopmental processes. These serve as molecular memories and have been associated with long term modifications of the offspring's stress regulatory system and increased susceptibility to psychosomatic disorders later in life. This review summarises our current understanding on the roles of CRH and other mediators of stress responses on fetal neurodevelopment.

Global prevalence of long-term neurodevelopmental impairment following extremely preterm birth: a systematic literature review

Objective

Neurodevelopmental impairment (NDI) is a major complication of extreme prematurity. This systematic review was conducted to summarize the worldwide long-term prevalence of NDI associated with extreme prematurity.

Methods

Embase and MEDLINE databases were searched for epidemiologic and observational/real-world studies, published in English between 2011 and 2016, reporting long-term prevalence of NDI (occurring from 1 year) among extremely preterm infants born at gestational age (GA) ≤28 weeks.

Results

Of 2406 articles identified through searches, 69 met the protocol NDI definition (24 North America, 25 Europe, 20 Rest of World). Prevalence of any severity NDI in North America was 8%–59% at 18 months to 2 years, and 11%–37% at 2–5 years; prevalence of moderate NDI in Europe was 10%–13% at 18 months to 2 years, 3% at 2–5 years, and 9%–19% at ≥5 years; prevalence of any NDI in Rest of World was 15%–61% at 18 months to 2 years, and 42% at 2–5 years (no North America/Rest of World studies reported any NDI at ≥5 years). A trend toward higher prevalence of NDI with lower GA at birth was observed.

Conclusions

Extreme prematurity has a significant long-term worldwide impact on neurodevelopmental outcomes.

Behavioural dysfunctions of 10-year-old children born extremely preterm associated with corticotropin-releasing hormone expression in the placenta

AIM

To evaluate the relationship between corticotropin-releasing hormone (CRH) expression in the placenta and the risk of school-related dysfunctions at the age of 10 years among children born extremely preterm (EP).

METHODS

Corticotropin-releasing hormone expression was measured in the placenta of 761 EP children, who had the following assessments at the age of 10 years: Differential Ability Scales, Oral and Written Language Scales, the Wechsler Individual Achievement Test-III, NEPSY-II and the Child Symptom Inventory-4. We evaluated whether lowest and highest quartiles of CRH mRNA were associated with undesirable scores on these assessments. With 272 evaluations, we would expect 14 to be significant at p < 0.05.

RESULTS

Only 16 associations were statistically significant. On the other hand, seven of these were social limitations among girls whose placenta CRH mRNA was in the top quartile. Adjusting for delivery indication or restricting the sample to one delivery indication group resulted in few differences.

CONCLUSION

Overall, placenta CRH mRNA concentrations in the top or bottom quartiles were not associated with increased risks of dysfunctions 10 years later. Girls whose placenta CRH expression was in the top quartile, however, were at increased risk of seven indicators/correlates of social limitations.

Should the Gross Motor Function Classification System be used for children who do not have cerebral palsy?

This literature review addressed four questions. (1) In which populations other than cerebral palsy (CP) has the Gross Motor Function Classification System (GMFCS) been applied? (2) In what types of study, and why was it used? (3) How was it modified to facilitate these applications? (4) What justifications and evidence of psychometric adequacy were used to support its application? A search of PubMed, MEDLINE, and Embase databases (January 1997 to April 2017) using the terms: 'GMFCS' OR 'Gross Motor Function Classification System' yielded 2499 articles. 118 met inclusion criteria and reported children/adults with 133 health conditions/clinical descriptions other than CP. Three broad GMFCS applications were observed: as a categorization tool, independent variable, or outcome measure. While the GMFCS is widely used for children with health conditions/clinical description other than CP, researchers rarely provided adequate justification for these uses. We offer recommendations for development/validation of other condition-specific classification systems and discuss the potential need for a generic gross motor function classification system.

WHAT THIS PAPER ADDS

The Gross Motor Function Classification System should not be used outside cerebral palsy or as an outcome measure. The authors provide recommendations for development and validation of condition-specific or generic classification systems.