Neonatal disorders of germinal matrix

Characterizing Genetic Pathways Unique to Autism Spectrum Disorder at Multiple Levels of Biological Analysis

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by atypical patterns of social functioning and repetitive/restricted behaviors. ASD commonly co-occurs with ADHD and, despite their clinical distinctiveness, the two share considerable genetic overlap. Given their shared genetic liability, it is unclear which genetic pathways confer unique risk for ASD independent of ADHD. We applied Genomic Structural Equation Modeling (SEM) to GWAS summary statistics for ASD and ADHD, decomposing the genetic signal for ASD into that which is unique to ASD (uASD) and that which is shared with ADHD. We computed genetic correlations between uASD and 75 external traits to estimate genetic overlap between uASD and other clinically relevant phenotypes. We went on to apply Stratified Genomic SEM to identify classes of genes enriched for uASD. Finally, we implemented Transcriptome-Wide SEM (T-SEM) to explore patterns of gene-expression associated with uASD. We observed positive genetic correlations between uASD and several external traits, most notably those relating to cognitive/educational outcomes and internalizing psychiatric traits. Stratified Genomic SEM showed that heritability for uASD was significantly enriched in genes involved in evolutionarily conserved processes, as well as for a histone mark in the germinal matrix. T-SEM revealed 83 unique genes with expression associated with uASD, many of which were novel. These findings delineate the unique biological underpinnings of ASD which exist independent of ADHD and demonstrate the utility of Genomic SEM and its extensions for disambiguating shared and unique risk pathways for genetically overlapping traits.

Role of the NF-kB/parkin/vegfr-1 pathway associated with hypoxic-ischemic insult in germinal matrix samples of newborn infants

OBJECTIVE

Given the high proliferative activity of germinal matrix and its direct correlation with hypoxemia, it is necessary to investigate the possible molecular regulation pathways, to understand the existing clinical relationship between the hypoxic-ischemic insult and the biomarkers NF-kB, AKT-3, Parkin, TRK-C and VEGFR-1.

METHODS

A hundred and eighteen germinal matrix samples of the central nervous system of patients who died in the first 28 days of life were submitted to histological and immunohistochemistry analysis to identify the tissue immunoexpression of those biomarkers related to asphyxia, prematurity, and death events within 24h.

RESULTS

A significantly increased tissue immunoexpression of NF-kB, AKT-3 and Parkin was observed in the germinal matrix of preterm infants. In addition, significantly decreased tissue immunoexpression of VEGFR-1 and NF-kB was observed in patients who experienced asphyxia followed by death within 24 hours.

CONCLUSIONS

The results suggest a direct involvement between the hypoxic-ischemic insult and NF-kB and VEGFR-1 markers since a decreased immunoexpression of these biomarkers was observed in asphyxiated patients. Furthermore, it is suggested that there was not enough time for VEGFR-1 to be transcribed, translated and expressed on the surface of the plasma membrane. This temporality can be observed in the relationship between NF-kB expression and the survival time of individuals who died within 24 hours, suggesting that this factor is essential for the production of VEGFR-1 and, therefore, to carry out the necessary remodeling effect to neovascularize the affected region.

Ultrasound imaging of preterm brain injury: fundamentals and updates

Neurosonography has become an essential tool for diagnosis and serial monitoring of preterm brain injury. Preterm infants are at significantly higher risk of hypoxic-ischemic injury, intraventricular hemorrhage, periventricular leukomalacia and post-hemorrhagic hydrocephalus. Neonatologists have become increasingly dependent on neurosonography to initiate medical and surgical interventions because it can be used at the bedside. While brain MRI is regarded as the gold standard for detecting preterm brain injury, neurosonography offers distinct advantages such as its cost-effectiveness, diagnostic utility and convenience. Neurosonographic signatures associated with poor long-term outcomes shape decisions regarding supportive care, medical or behavioral interventions, and family members' expectations. Within the last decade substantial progress has been made in neurosonography techniques, prompting an updated review of the topic. In addition to the up-to-date summary of neurosonography, this review discusses the potential roles of emerging neurosonography techniques that offer new functional insights into the brain, such as superb microvessel imaging, elastography, three-dimensional ventricular volume assessment, and contrast-enhanced US.

A unique brain germinal matrix involvement in cytomegalovirus infected fetuses: A retrospective neurosonographic analysis with outcome correlation

OBJECTIVE

To study the clinical significance of brain germinal matrix (GM) changes in cytomegalovirus (CMV) infected fetuses.

METHOD

This is a retrospective analysis. Group A; isolated GM finding, with or without lenticulostriatal vasculopathy (LSV). Group B; non-isolated lesion. Amniocentesis, urinalysis, postnatal US and developmental assessment, were obtained.

RESULTS

Group A and B included 18 and four fetuses, respectively. In group A, mean fetal age at diagnosis was 34.3 weeks (31-38 weeks). In 15/18 (83.3%), the lesion was bilateral and LSV was present in 8/18 (44.4%). Small cysts appeared inside the lesion in 5/18 (27.7%). MRI was normal in 8/18 (44.4%). Subtle or inconclusive findings were reported in the remaining fetuses. Brain ultrasound was normal in 10/18 (55.5%) of newborns. In the remaining, caudothalamic cyst with or without LSV, or isolated LSV were found. All newborns are developing normally at a mean follow-up age of 33.3 months (+/- 19.6 moths). In group B, all four patients requested for termination of pregnancy.

CONCLUSION

Fetal CMV infection may cause focal GM changes, frequently accompanied by LSV, late in pregnancy. These changes may be isolated, or as part of a more generalized brain damage. When isolated, favorable prognosis is expected.

Role of Fibronectin-1 polymorphism genes with the pathogenesis of intraventricular hemorrhage in preterm infants

BACKGROUND/INTRODUCTION

Intraventricular hemorrhage (IVH) is a dangerous complication facing a significant proportion of preterm infants. It is multifactorial in nature, and an observed fibronectin deficiency in the germinal matrix basal lamina is among the most prominent factors that influence such rupture. Better understanding of the FN1 gene polymorphisms and their role in IVH may further clarify the presence of a genetic susceptibility of certain babies to this complication. The aim of this study was to assess if 5 single nucleotide polymorphisms of the fibronectin gene may be linked to an increased incidence of IVH.

MATERIAL AND METHODS

The study included 108 infants born between 24 and 32 weeks of gestation. IVH was diagnosed using cranial ultrasound performed on the 1st,3rd, and 7th day after birth and classified according to Papile et al. IVH classification. The 5 FN1 gene polymorphisms assessed in the study were the following: rs3796123; rs1968510; rs10202709; rs6725958; and rs35343655.

RESULTS

IVH developed in 51 (47.2%) out of the 108 preterm infants. This includes, 18 (35.3%) with stage I IVH, 19 (37.3%) with stage II, 11 (21.6%) with stage III, and 3 (5.9%) with stage IV IVH. Incidence of IVH was higher in infants with lower APGAR scores, low gestational age, and low birthweight. Analysis showed that IVH stage II to IV was approximately seven times more likely to occur in infants with the genotype TT FN1 rs10202709 (OR 7237 (1046-79.59; p = 0,044)). No other significant association was found with the rest of the polymorphisms.

CONCLUSION

The results of our study indicate a sevenfold increased genetic susceptibility to IVH in preterm infants with the TT FN1 rs10202709 gene polymorphism. The fibronectin gene polymorphism may therefore be of crucial importance as a genetic risk factor for IVH in preterm infants. Further studies are warranted.

Cranial ultrasound findings in preterm germinal matrix haemorrhage, sequelae and outcome

Germinal matrix-intraventricular haemorrhage (GMH-IVH), periventricular haemorrhagic infarction (PHI) and its complication, post-haemorrhagic ventricular dilatation (PHVD), are still common neonatal morbidities in preterm infants that are highly associated with adverse neurodevelopmental outcome. Typical cranial ultrasound (CUS) findings of GMH-IVH, PHI and PHVD, their anatomical substrates and underlying mechanisms are discussed in this paper. Furthermore, we propose a detailed descriptive classification of GMH-IVH and PHI that may improve quality of CUS reporting and prediction of outcome in infants suffering from GMH-IVH/PHI.

Prophylactic Early Erythropoietin for Neuroprotection in Preterm Infants: A Meta-analysis

CONTEXT

Recombinant human erythropoietin (rhEPO) is a promising pharmacological agent for neuroprotection in neonates.

OBJECTIVE

To investigate whether prophylactic rhEPO administration in very preterm infants improves neurodevelopmental outcomes in a meta-analysis of randomized controlled trials (RCTs).

DATA SOURCES

Medline, Embase, and the Cochrane Central Register of Controlled Trials were searched in December 2016 and complemented by other sources.

STUDY SELECTION

RCTs investigating the use of rhEPO in preterm infants versus a control group were selected if they were published in a peer-reviewed journal and reported neurodevelopmental outcomes at 18 to 24 months' corrected age.

DATA EXTRACTION

Data extraction and analysis followed the standard methods of the Cochrane Neonatal Review Group. The primary outcome was the number of infants with a Mental Developmental Index (MDI) <70 on the Bayley Scales of Infant Development. Secondary outcomes included a Psychomotor Development Index <70, cerebral palsy, visual impairment, and hearing impairment.

RESULTS

Four RCTs, comprising 1133 infants, were included in the meta-analysis. Prophylactic rhEPO administration reduced the incidence of children with an MDI <70, with an odds ratio (95% confidence interval) of 0.51 (0.31-0.81), P < .005. The number needed to treat was 14. There was no statistically significant effect on any secondary outcome.

CONCLUSIONS

Prophylactic rhEPO improved the cognitive development of very preterm infants, as assessed by the MDI at a corrected age of 18 to 24 months, without affecting other neurodevelopmental outcomes. Current and future RCTs should investigate optimal dosing and timing of prophylactic rhEPO and plan for long-term neurodevelopmental follow-up.