White matter damage in preterm newborns--an epidemiologic perspective

Long-term neurodevelopmental outcomes at three years in preterm infants born before 29 Weeks gestation following Preterm Premature Rupture of Membranes (PPROM)

OBJECTIVE

To determine the association between preterm premature rupture of membranes (PPROM) and neurodevelopmental impairment (NDI) at 3 years corrected age (CA) in infants born before 29 weeks of gestational age (GA).

DESIGN/METHODS

Infants born before 29 weeks GA between 2005 and 2017 were included. The primary outcome was a composite of death or NDI (full-scale intelligence quotient<85, cerebral palsy, vision or hearing impairment) at 3 years of CA. Infants were stratified by maternal PPROM status. Associations were explored using multivariate models.

RESULTS

Of 1231 participants, 481 were in the PPROM group, and 750 were in the No PPROM group. After adjusting for factors, the odds ratio of death or NDI for PPROM vs. No PPROM was 1.22 (95% Confidence Interval 0.93-1.59).

CONCLUSION

Our study suggests that PPROM was not associated with an increased risk of a composite outcome of death or NDI at 3 years CA.

Impact of early brain lesions on the optic radiations in children with cerebral palsy

Due to their early brain lesion, children with unilateral spastic cerebral palsy (USCP) present important changes in brain gray and white matter, often manifested by perturbed sensorimotor functions. We predicted that type and side of the lesion could influence the microstructure of white matter tracts. Using diffusion tensor imaging in 40 children with USCP, we investigated optic radiation (OR) characteristics: fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). First, we compared the OR of the lesional and non-lesional hemisphere. Then we evaluated the impact of the brain lesion type (periventricular or cortico-subcortical) and side in the differences observed in the lesional and non-lesional OR. Additionally, we examined the relationship between OR characteristics and performance of a visuospatial attention task. We observed alterations in the OR of children with USCP on the lesional hemisphere compared with the non-lesional hemisphere in the FA, MD and RD. These differences were influenced by the type of lesion and by the side of the lesion. A correlation was also observed between FA, MD and RD and the visuospatial assessment mainly in children with periventricular and right lesions. Our results indicate an important role of the timing and side of the lesion in the resulting features of these children’s OR and probably in the compensation resulting from neuroplastic changes.

Serum brain injury biomarkers are gestationally and post-natally regulated in non-brain injured neonates

BACKGROUND

To determine the association of gestational age (GA) and day of life (DOL) with the circulating serum concentration of six brain injury-associated biomarkers in non-brain injured neonates born between 23 and 41 weeks' GA.

METHODS

In a multicenter prospective observational cohort study, serum CNS-insult, inflammatory and trophic proteins concentrations were measured daily in the first 7 DOL.

RESULTS

Overall, 3232 serum samples were analyzed from 745 enrollees, median GA 32.3 weeks. BDNF increased 3.7% and IL-8 increased 8.9% each week of gestation. VEGF, IL-6, and IL-10 showed no relationship with GA. VEGF increased 10.8% and IL-8 18.9%, each DOL. IL-6 decreased by 15.8% each DOL. IL-10 decreased by 81.4% each DOL for DOL 0-3. BDNF did not change with DOL. Only 49.67% of samples had detectable GFAP and 33.15% had detectable NRGN. The odds of having detectable GFAP and NRGN increased by 53% and 11%, respectively, each week after 36 weeks' GA. The odds of having detectable GFAP and NRGN decreased by 15% and 8%, respectively, each DOL.

CONCLUSIONS

BDNF and IL-8 serum concentrations vary with GA. VEGF and interleukin concentrations are dynamic in the first week of life, suggesting circulating levels should be adjusted for GA and DOL for clinically relevant assessment of brain injury.

IMPACT

Normative data of six brain injury-related biomarkers is being proposed. When interpreting serum concentrations of brain injury biomarkers, it is key to adjust for gestational age at birth and day of life during the first week to correctly assess for clinical brain injury in neonates. Variation in levels of some biomarkers may be related to gestational and postnatal age and not necessarily pathology.

Mesenchymal stem cell-derived secretomes for therapeutic potential of premature infant diseases

Preterm birth is a complex syndrome and remains a substantial public health problem globally. Its common complications include periventricular leukomalacia (PVL), bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC) and retinopathy of prematurity (ROP). Despite great advances in the comprehension of the pathogenesis and improvements in neonatal intensive care and associated medicine, preterm birth-related diseases remain essentially without adequate treatment and can lead to high morbidity and mortality. The therapeutic potential of mesenchymal stem/stromal cells (MSCs) appears promising as evidenced by their efficacy in preclinical models of pathologies relevant to premature infant complications. MSC-based therapeutic efficacy is closely associated with MSC secretomes and a subsequent paracrine action response to tissue injuries, which are complex and abundant in response to the local microenvironment. In the current review, we summarize the paracrine mechanisms of MSC secretomes underlying diverse preterm birth-related diseases, including PVL, BPD, NEC and ROP, are summarized, and focus is placed on MSC-conditioned media (CM) and MSC-derived extracellular vesicles (EVs) as key mediators of modulatory action, thereby providing new insights for future therapies in newborn medicine.

Glutamate Transport and Preterm Brain Injury

Preterm birth complications are the leading cause of child death worldwide and a top global health priority. Among the survivors, the risk of life-long disabilities is high, including cerebral palsy and impairment of movement, cognition, and behavior. Understanding the molecular mechanisms of preterm brain injuries is at the core of future healthcare improvements. Glutamate excitotoxicity is a key mechanism in preterm brain injury, whereby the accumulation of extracellular glutamate damages the delicate immature oligodendrocytes and neurons, leading to the typical patterns of injury seen in the periventricular white matter. Glutamate excitotoxicity is thought to be induced by an interaction between environmental triggers of injury in the perinatal period, particularly cerebral hypoxia-ischemia and infection/inflammation, and developmental and genetic vulnerabilities. To avoid extracellular build-up of glutamate, the brain relies on rapid uptake by sodium-dependent glutamate transporters. Astrocytic excitatory amino acid transporter 2 (EAAT2) is responsible for up to 95% of glutamate clearance, and several lines of evidence suggest that it is essential for brain functioning. While in the adult EAAT2 is predominantly expressed by astrocytes, EAAT2 is transiently upregulated in the immature oligodendrocytes and selected neuronal populations during mid-late gestation, at the peak time for preterm brain injury. This developmental upregulation may interact with perinatal hypoxia-ischemia and infection/inflammation and contribute to the selective vulnerability of the immature oligodendrocytes and neurons in the preterm brain. Disruption of EAAT2 may involve not only altered expression but also impaired function with reversal of transport direction. Importantly, elevated EAAT2 levels have been found in the reactive astrocytes and macrophages of human infant post-mortem brains with severe white matter injury (cystic periventricular leukomalacia), potentially suggesting an adaptive mechanism against excitotoxicity. Interestingly, EAAT2 is suppressed in animal models of acute hypoxic-ischemic brain injury at term, pointing to an important and complex role in newborn brain injuries. Enhancement of EAAT2 expression and transport function is gathering attention as a potential therapeutic approach for a variety of adult disorders and awaits exploration in the context of the preterm brain injuries.

Inhibitory Effect of LPS on the Proliferation of Oligodendrocyte Precursor Cells through the Notch Signaling Pathway in Intrauterine Infection-induced Rats

Periventricular white matter injury (PWMI) is very common in survivors of premature birth, and the final outcomes are a reduction in myelinated neurons leading to white matter hypomyelination. How and (or) why the oligodendrocyte lineage develops abnormally and myelination is reduced is a hot topic in the field. This study focuses on the effect of intrauterine inflammation on the proliferation of oligodendrocyte lineage cells and the underlying mechanisms. Lipopolysaccharide (LPS) (300 μg/kg) was intraperitoneally injected into pregnant Sprague-Dawley rats at embryonic days 19 and 20 to establish a rat model of intrauterine infection-induced white matter injury. Corpus callosum tissues were collected at postnatal day 14 (P14) to quantify the number of oligodendrocytes, the number and proliferation of oligodendrocyte precursor cells (OPCs), and the expression of myelin proteins (MBP and PLP). Furthermore, the expression of Wnt and Notch signaling-related proteins was analyzed. The results showed that the number of oligodendrocytes in the corpus callosum tissues of LPS-treated rats was reduced, and the expression levels of myelinating proteins were down-regulated. Further analysis showed that the Notch signaling pathway was down-regulated in the LPStreated group. These results indicate that intrauterine LPS may inhibit the proliferation of OPCs by down-regulating the Notch rather than the Wnt signaling pathway, leading to hypomyelination of white matter.

Enhanced autophagy contributes to excitotoxic lesions in a rat model of preterm brain injury

Cystic periventricular leukomalacia is commonly diagnosed in premature infants, resulting from severe hypoxic-ischemic white matter injury, and also involving some grey matter damage. Very few is known concerning the cell death pathways involved in these types of premature cerebral lesions. Excitotoxicity is a predominant mechanism of hypoxic-ischemic injury in the developing brain. Concomitantly, it has been recently shown that autophagy could be enhanced in excitotoxic conditions switching this physiological intracellular degradation system to a deleterious process. We here investigated the role of autophagy in a validated rodent model of preterm excitotoxic brain damage mimicking in some aspects cystic periventricular leukomalacia. An excitotoxic lesion affecting periventricular white and grey matter was induced by injecting ibotenate, a glutamate analogue, in the subcortical white matter (subcingulum area) of five-day old rat pups. Ibotenate enhanced autophagy in rat brain dying neurons at 24 h as shown by increased presence of autophagosomes (increased LC3-II and LC3-positive dots) and enhanced autophagic degradation (SQSTM1 reduction and increased number and size of lysosomes (LAMP1- and CATHEPSIN B-positive vesicles)). Co-injection of the pharmacological autophagy inhibitor 3-methyladenine prevented not only autophagy induction but also CASPASE-3 activation and calpain-dependent cleavage of SPECTRIN 24 h after the insult, thus providing a strong reduction of the long term brain injury (16 days after ibotenate injection) including lateral ventricle dilatation, decreases in cerebral tissue volume and in subcortical white matter thickness. The autophagy-dependent neuroprotective effect of 3-methyladenine was confirmed in primary cortical neuronal cultures using not only pharmacological but also genetic autophagy inhibition of the ibotenate-induced autophagy. Strategies inhibiting autophagy could then represent a promising neuroprotective approach in the context of severe preterm brain injuries.

Neuroinflammation-Related Encephalopathy in an Infant Born Preterm Following Exposure to Maternal Diabetic Ketoacidosis

A pregnant woman with new-onset type 1 diabetes and ketoacidosis delivered an infant at 28 weeks of gestation who died with multiple organ failure and severe cerebral vasculopathy with extensive hemorrhage, diffuse microgliosis, and edema. This illustrates that antenatal metabolic and inflammatory stressors may be associated with neonatal encephalopathy and cerebral hemorrhage.

Correlation of nerve fibers in corpus callosum and number of neurons in cerebral cortex: an innovative mathematical model

Purpose/aim: It is estimated that 10⁹ bits/s information are processed in the human brain. The transmission of this huge amount of information requires all connections in the brain to be highly accurate and have order. The current study attempted to present a new aspect of order and proportion in the ultra-structure of the human brain and to calculate the degree of neural interdependence between the two hemispheres.

MATERIALS AND METHODS

In this model, intensity of interdependence of the brain to hemispheres is estimated to be equal to the mathematical proportion of number of neurons in cerebral cortex divided by 2 (number of hemispheres), divided by number of nerve fibers in the human corpus callosum.

RESULTS

The calculated number is equal to 30-50 and it indicates that for every 30-50 neurons between the two hemispheres, there is a neural interconnecting bridge.

CONCLUSIONS

This connection indicates that the brain's function output follows a mathematical relation.

Differentiation of human olfactory bulb-derived neural stem cells toward oligodendrocyte

In the central nervous system (CNS), oligodendrocytes are the glial element in charge of myelin formation. Obtaining an overall presence of oligodendrocyte precursor cells/oligodendrocytes (OPCs/OLs) in culture from different sources of NSCs is an important research area, because OPCs/OLs may provide a promising therapeutic strategy for diseases affecting myelination of axons. The present study was designed to differentiate human olfactory bulb NSCs (OBNSCs) into OPCs/OLs and using expression profiling (RT-qPCR) gene, immunocytochemistry, and specific protein expression to highlight molecular mechanism(s) underlying differentiation of human OBNSCs into OPCs/OLs. The differentiation of OBNSCs was characterized by a simultaneous appearance of neurons and glial cells. The differentiation medium, containing cAMP, PDGFA, T3, and all-trans-retinoic acid (ATRA), promotes OBNSCs to generate mostly oligodendrocytes (OLs) displaying morphological changes, and appearance of long cytoplasmic processes. OBNSCs showed, after 5 days in OLs differentiation medium, a considerable decrease in the number of nestin positive cells, which was associated with a concomitant increase of NG2 immunoreactive cells and few O4(+)-OPCs. In addition, a significant up regulation in gene and protein expression profile of stage specific cell markers for OPCs/OLs (CNPase, Galc, NG2, MOG, OLIG1, OLIG2, MBP), neurons, and astrocytes (MAP2, β-TubulinIII, GFAP) and concomitant decrease of OBNSCs pluripotency markers (Oct4, Sox2, Nestin), was demonstrated following induction of OBNSCs differentiation. Taken together, the present study demonstrate the marked ability of a cocktail of factors containing PDGFA, T3, cAMP, and ATRA, to induce OBNSCs differentiation into OPCs/OLs and shed light on the key genes and pathological pathways involved in this process.

Association between perinatal hypoxic-ischemia and periventricular leukomalacia in preterm infants: A systematic review and meta-analysis

Background

Although investigators have implicated hypoxic-ischemia (HI) as a potential cause of periventricular leukomalacia (PVL), the role of clinical risk factors or markers for HI in the development of PVL remains controversial. The aim of this study was to identify perinatal HI-related factors associated with PVL.

Method

The PubMed, EMBASE, and Cochrane Library databases were searched. The last search was performed on January 2017. Summary effect estimates (pooled odds ratios [ORs]) were calculated for each risk factor using fixed or random effects models with tests for heterogeneity and publication bias.

Results

Fifteen studies with a total of 12,851 participants were included in this meta-analysis, and 14 potential risk factors were analyzed. The pooled results showed that mothers with oligohydramnios (OR, 1.55; 95% confidence interval [CI], 1.05 to 2.30), preterm infants with acidemia (OR, 1.87; 95% CI, 1.18 to 2.97), 1-minute Apgar score <7 (OR 2.69; 95% CI, 1.13 to 6.41), 5-minute Apgar score <7 (OR, 1.89; 95% CI, 1.39 to 2.56), apnea (OR, 1.76; 95% CI, 1.07 to 2.90), respiratory distress syndrome (OR, 1.46; 95% CI, 1.04 to 2.03), and seizures (OR, 4.60; 95% CI, 2.84 to 7.46) were associated with increased risk of PVL.

Conclusion

This study identified perinatal HI-related risk factors for the development of PVL in preterm infants. Future large-scale prospective clinical studies are required to validate and extend these findings.

Human Amnion Epithelial Cells Protect Against White Matter Brain Injury After Repeated Endotoxin Exposure in the Preterm Ovine Fetus

Intrauterine inflammation is a significant cause of injury to the developing fetal brain. Using a preterm fetal sheep model of in utero infection, we asked whether human amnion epithelial cells (hAECs) were able to reduce inflammation-induced fetal brain injury. Surgery was undertaken on pregnant sheep at ∼105 days gestation (term is 147 days) for implantation of vascular catheters. Lipopolysaccharide (LPS; 150 ng/kg bolus) or saline was administered IV at 109, 110, and 111 days. Sixty million fluorescent-labeled hAECs were administered at 110, 111, and 112 days gestation via the brachial artery catheter. Brains were collected at 114 days for histological assessment. hAECs were observed within the cortex, white matter, and hippocampus. Compared to control lambs, LPS administration was associated with significant and widespread fetal brain inflammation and injury as evidenced by increased number of activated microglia in the periventricular white matter (p = 0.02), increased pyknosis, cell degeneration (p = 0.01), and a nonsignificant trend of fewer oligodendrocytes in the subcortical and periventricular white matter. Administration of hAECs to LPS-treated animals was associated with a significant mitigation in both inflammation and injury as evidenced by fewer activated microglia (p = 0.03) and pyknotic cells (p = 0.03), significantly more oligodendrocytes in the subcortical and periventricular white matter (p = 0.01 and 0.02, respectively), and more myelin basic protein-positive cells within the periventricular white matter (p = 0.02). hAEC administration to fetal sheep exposed to multiple doses of LPS dampens the resultant fetal inflammatory response and mitigates associated brain injury.

Ultrasonographic approach to diagnosis of fetal inflammatory response syndrome: a tool for at-risk fetuses?

Preterm parturition is a syndrome that may result from many underlying mechanisms. Infection and inflammation are the prominent ones. Intrauterine infection and inflammation have an effect akin to sepsis, and that is similar to systemic inflammatory response in adults. Indeed, there is evidence to support the association of a fetal inflammatory response syndrome (FIRS) to systemic infection and inflammation. The utilization of invasive procedures for the prenatal diagnosis of FIRS is associated with a risk for complications resulting from the invasive method. The progress in the imaging quality of obstetrical ultrasound and the development of novel methods for functional anatomical assessment of the fetal organs may help to identify, noninvasively, fetuses at risk for FIRS in patients presenting with preterm labor. We review the studies describing advanced sonographic modalities and the imaging findings in the heart, thymus, kidney, adrenal glands, and spleen of these fetuses.

Risk factors for periventricular white matter injury in very low birthweight neonates

BACKGROUND

The development of periventricular white matter injury (PWMI) in the preterm neonate is the most common insult portending neurologic impairment and is linked with the later development of cerebral palsy. The pathogenesis of PWMI targets premyelinating oligodendrocytes of the periventricular region secondary to free radicals, cytokine toxicity, and excitatory neurotransmitters. The primitive nature of the vasculature in the developing fetal cortex lends to its predilection to PWMI and cerebral ischemia with less arterial anastomoses at arterial border zones and failure to compensate for global hypotension, termed the "pressure-passive" circulation.

OBJECTIVE

Our objective is to determine the relative risk (RR) of fetal metabolic acidosis and perinatal infection in the development of PWMI in very low birthweight (VLBW) (<1500 g) neonates.

STUDY DESIGN

This is a cohort study of all VLBW neonates admitted to our neonatal intensive care unit from April 2009 through December 2014, comparing those who developed PWMI on neonatal head ultrasound at 6 weeks of life to those who did not. Neonates with chromosomal or major congenital abnormalities were excluded. Generalized linear modeling, adjusting for variables significantly different on bivariate analysis, was conducted.

RESULTS

During this 5-year and 8-month period there were 374 VLBW neonates admitted; 35 (9.4%) had PWMI. VLBW neonates without PWMI were significantly more likely to have intrauterine growth restriction (2.9% PWMI, 21.5% no PWMI; P = .006), while those neonates with PWMI had a significantly lower gestational age (26.3 ± 2.2 vs 28.0 ± 2.5 weeks; P < .001) and birthweight (868 ± 237 vs 993 ± 276 g; P = .009). There was no significant difference in umbilical arterial pH (7.25 ± 0.15 vs 7.27 ± 0.09; P = .34), base deficit (4.6 ± 6.0 vs 3.4 ± 3.3 mmol/L; P = .11), or pH <7.0 or base deficit >12 mmol/L at birth (10.7% vs 3.2%; P = .09). On bivariate analysis neonates with PWMI had a significant increase in positive cerebrospinal fluid (CSF) cultures (22.9% vs 1.5%; P < .001). The initial lumbar puncture was performed at a similar day of life, and neonates with PWMI had significantly elevated CSF white blood cell counts (5%, 50%, and 95%; 16, 175, and 709/mm(3); 1, 3, and 27/mm(3); P = .008). Generalized linear modeling, adjusted for gestational age and the presence of intrauterine growth restriction, showed that fetal metabolic acidosis had RR 2.59 (95% confidence interval, 1.14-5.92; P = .02) and neonatal CSF infection had RR 4.94 (95% confidence interval, 2.4-10.3; P < .001) for association with PWMI.

CONCLUSION

The RR of neonatal CSF infection being associated with PWMI was 2-fold greater than metabolic acidosis at the time of birth. Decreasing the incidence of CSF infections would have a greater impact on preventing PWMI, a precursor of cerebral palsy.

Timing of cord clamping in very preterm infants: more evidence is needed

In December 2012, the American College of Obstetricians and Gynecologists published a Committee Opinion entitled "Timing of umbilical cord clamping after birth." It stated that "evidence exists to support delayed cord clamping in preterm infants, when feasible. The single most important benefit for preterm infants is the possibility for a nearly 50% reduction in IVH." However, the Committee Opinion added that the ideal timing of umbilical cord clamping has yet to be determined and recommended that large clinical trials be conducted in the most preterm infants. Published randomized controlled trials include <200 infants of <30 weeks' gestation, with assessments of neurodevelopmental outcome in less than one-half of the children. This is a major gap in the evidence. Without reliable data from randomized controlled trials that optimally include childhood follow-up evaluations, we will not know whether delayed cord clamping may do more overall harm than good. Ongoing trials of delayed cord clamping plan to report childhood outcomes in >2000 additional very preterm infants. Current recommendations may need to change when these results become available. Greater international collaboration could accelerate resolution of whether this promising intervention will improve disability-free survival in about 1 million infants who will be born very preterm globally each year.

Latency after preterm prelabor rupture of the membranes: increased risk for periventricular leukomalacia

Objective. To identify the risk factors for cystic periventricular leukomalacia (cPVL) and their implications for deciding between immediate delivery and conservative management of preterm prelabor rupture of the membranes (pPROM). Methods. The following risk factors were compared between cPVL infants and 6440 controls: chorioamnionitis, sex, gestational age (GA), birth weight, pPROM, and pPROM-delivery interval. Factor impact on cPVL risk and clinical decision-making was determined by multivariate logistic regression. Results. Overall cPVL prevalence (n = 32) was 0.99/1000 births. All cPVL infants but one were born <34 weeks of gestation and were <2500 g; 56% had histological chorioamnionitis versus 1.1% of controls (OR 35.9; 95%-CI 12.6–102.7). Because chorioamnionitis is a postnatal diagnosis, logistic regression was performed with prenatally available factors: pPROM-delivery interval >48 hours (OR 9.0; 95%-CI 4.1–20.0), male gender (OR 3.2; 95%-CI 1.4–7.3). GA was not a risk factor if birth weight was included. Risk decreased with increasing fetal weight despite a prolonged pPROM-delivery interval. Conclusion. pPROM-delivery interval is the single most important prenatally available risk factor for the development of cPVL. Immediate delivery favors babies with chorioamnionitis but disfavors those with non infectious pPROM. In the absence of clinical chorioamnionitis fetal weight gain may offset the inflammatory risk of cPVL caused by a prolonged pPROM-delivery interval.

Neurodevelopmental outcomes of infants born prematurely

Long-term follow-up of infants born prematurely is necessary to determine neurodevelopmental outcomes, particularly with the expansion of interest from major disabilities to high prevalence/low severity dysfunctions. Models of pathogenesis include changes due to developmental disruptions and to injury, the magnitude and type of change influenced by the infant's age, and central nervous system recovery and reorganization. Alterations in neurogenesis, migration, myelination, cell death, and synaptogenesis occur even in the absence of insult. Despite increased knowledge regarding these processes, the functional significance of brain abnormalities is unclear. Because of methodologic problems in follow-up studies, it is difficult to characterize outcome definitively. Nonetheless, an acceptable degree of agreement across studies is found with regard to specific neurodevelopmental outcomes: motor/neurologic function, visuomotor integrative skills, IQ, academic achievement, language, executive function, and attention-deficit hyperactivity disorder/behavioral issues. In general, children born prematurely have more problems in these areas than do their normal birth weight counterparts. Suggestions for improved analyses and clarification of outcomes include use of cluster analysis, structural equation modeling, growth curve analysis, developmental epidemiologic approaches, and better control of background variables using risk indexes and factor scores. Better assessment techniques measuring functions documented to be at higher risk of problems are discussed.

Ischemia/Reperfusion-induced neovascularization in the cerebral cortex of the ovine fetus

Information on the effects of injury on neovascularization in the immature brain is limited. We investigated the effects of ischemia on cerebral cortex neovascularization after the exposure of fetuses to 30 minutes of cerebral ischemia followed by 48 hours of reperfusion (I/R-48), 30 minutes of cerebral ischemia followed by 72 hours of reperfusion (I/R-72), or sham control treatment (Non-I/R). Immunohistochemical and morphometric analyses of cerebral cortex sections included immunostaining for glial fibrillary acidic protein and collagen type IV (a molecular component of the vascular basal lamina) to determine the glial vascular network in fetal brains and Ki67 as a proliferation marker. Cerebral cortices from I/R-48 and I/R-72 fetuses exhibited general responses to ischemia, including reactive astrocyte morphology, which was not observed in Non-I/R fetuses. Cell bodies of reactive proliferating astrocytes, along with large end-feet, surrounded the walls of cerebral cortex microvessels in addition to the thick collagen type IV-enriched basal lamina. Morphometric analysis of the Non-I/R group with the I/R-48 and I/R-72 groups revealed increased collagen type IV density in I/R-72 cerebral cortex microvessels (p < 0.01), which also frequently displayed a sprouting appearance characterized by growing tip cells and activated pericytes. Increases in cerebral cortex basic fibroblast growth factor were associated with neovascularization. We conclude that increased neovascularization in fetal cerebral cortices occurs within 72 hours of ischemia.

Stem cell therapy to protect and repair the developing brain: a review of mechanisms of action of cord blood and amnion epithelial derived cells

In the research, clinical, and wider community there is great interest in the use of stem cells to reduce the progression, or indeed repair brain injury. Perinatal brain injury may result from acute or chronic insults sustained during fetal development, during the process of birth, or in the newborn period. The most readily identifiable outcome of perinatal brain injury is cerebral palsy, however, this is just one consequence in a spectrum of mild to severe neurological deficits. As we review, there are now clinical trials taking place worldwide targeting cerebral palsy with stem cell therapies. It will likely be many years before strong evidence-based results emerge from these trials. With such trials underway, it is both appropriate and timely to address the physiological basis for the efficacy of stem-like cells in preventing damage to, or regenerating, the newborn brain. Appropriate experimental animal models are best placed to deliver this information. Cell availability, the potential for immunological rejection, ethical, and logistical considerations, together with the propensity for native cells to form teratomas, make it unlikely that embryonic or fetal stem cells will be practical. Fortunately, these issues do not pertain to the use of human amnion epithelial cells (hAECs), or umbilical cord blood (UCB) stem cells that are readily and economically obtained from the placenta and umbilical cord discarded at birth. These cells have the potential for transplantation to the newborn where brain injury is diagnosed or even suspected. We will explore the novel characteristics of hAECs and undifferentiated UCB cells, as well as UCB-derived endothelial progenitor cells (EPCs) and mesenchymal stem cells (MSCs), and how immunomodulation and anti-inflammatory properties are principal mechanisms of action that are common to these cells, and which in turn may ameliorate the cerebral hypoxia and inflammation that are final pathways in the pathogenesis of perinatal brain injury.

Serial assessment of left-ventricular function using tissue Doppler imaging in premature infants within 7 days of life

Although many echocardiographic parameters can assess cardiac function noninvasively in preterm infants, it has not been determined what indices are the best. We assessed left-ventricular performance in 101 very low-birth weight (VLBW) infants using tissue Doppler imaging (TDI) echocardiography. Echocardiographic examinations, including TDI, were performed serially within 7 days of life. Pulsed-Doppler TDI waveforms were recorded at the mitral valve annulus, and peak systolic velocities (Sa), early diastolic velocities (Ea), and late diastolic velocities (Aa) were measured. Sa and Aa velocities were both decreased significantly from 3 to 12 h and then gradually increased. Ea velocities showed no significant, longitudinal changes, but Ea values in premature groups appeared to be significantly lower than those in mature groups. The ratio of E to Ea (E/Ea) of VLBW infants seemed to be almost stable from birth to day 7, and this also showed no significant differences between different gestational age groups. E/Ea values in infants with patent ductus arteriosus (PDA) appeared to be greater than those in non-PDA infants. Our present findings suggest that TDI assessment in the early neonatal period might be useful in detecting latent systolic/diastolic failure of critically ill preterm infants.

Glial fibrillary acidic protein as a biomarker for periventricular white matter injury

OBJECTIVE

Periventricular white matter injury (PWMI), a precursor of cerebral palsy, traditionally is not diagnosed until 6 weeks of life by head ultrasound scanning. We sought to determine whether early neonatal glial fibrillary acidic protein (GFAP) levels could identify PWMI in low birthweight (<2500 g) infants.

STUDY DESIGN

Each case with PWMI on head ultrasound scanning at 6 weeks of life from April 2009 to April 2011 was matched by gestational age and mode of delivery to 2 subsequent neonates with a normal head ultrasound scan. GFAP was measured in cord blood at birth, at neonatal intensive care unit admission, and on days 1-4 of life.

RESULTS

During this 2-year period, 21 cases with PWMI with gestational age 27.4 ± 3.3 weeks were compared with 42 control infants. The incidence of cesarean delivery was 61.9% in both groups. GFAP was not significantly different in cord blood or at neonatal intensive care unit admission but was significantly elevated on day 1 (median, 5-95%; 0, 0-0.98 ng/mL cases; 0, 0-0.06 ng/mL control infants; P = .03), day 2 (0, 0-1.21 ng/mL; 0, 0-0.05 ng/mL, respectively; P = .02), day 3 (0.05, 0-0.33 ng/mL; 0, 0-0.04 ng/mL, respectively; P = .004), and day 4 (0.02, 0-1.03 ng/mL; 0, 0-0.05 ng/mL, respectively; P < .001). The odds of the development of PWMI significantly increased with increasing levels of GFAP from day 1-4 of life when adjustment was made for preeclampsia, antenatal steroid administration, and neonatal chronic lung disease.

CONCLUSION

The ability to predict PWMI with a blood test for GFAP shortly after birth opens the possibility for rapid identification of infants for early intervention and provides a benchmark for the qualification of new therapies to improve neurodevelopmental outcomes.

Human amnion epithelial cells reduce fetal brain injury in response to intrauterine inflammation

Intrauterine infection, such as occurs in chorioamnionitis, is a principal cause of preterm birth and is a strong risk factor for neurological morbidity and cerebral palsy. This study aims to examine whether human amnion epithelial cells (hAECs) can be used as a potential therapeutic agent to reduce brain injury induced by intra-amniotic administration of lipopolysaccharide (LPS) in preterm fetal sheep. Pregnant ewes underwent surgery at approximately 110 days of gestation (term is approx. 147 days) for implantation of catheters into the amniotic cavity, fetal trachea, carotid artery and jugular vein. LPS was administered at 117 days; hAECs were labeled with carboxyfluorescein succinimidyl ester and administered at 0, 6 and 12 h, relative to LPS administration, into the fetal jugular vein, trachea or both. Control fetuses received an equivalent volume of saline. Brains were collected 7 days later for histological assessment of brain injury. Microglia (Iba-1-positive cells) were present in the brain of all fetuses and were significantly increased in the cortex, subcortical and periventricular white matter in fetuses that received LPS, indicative of inflammation. Inflammation was reduced in fetuses that received hAECs. In LPS fetuses, the number of TUNEL-positive cells was significantly elevated in the cortex, periventricular white matter, subcortical white matter and hippocampus compared with controls, and reduced in fetuses that received hAECs in the cortex and periventricular white matter. Within the fetal brains studied there was a significant positive correlation between the number of Iba-1-immunoreactive cells and the number of TUNEL-positive cells (R(2) = 0.19, p < 0.001). The administration of hAECs protects the developing brain when administered concurrently with the initiation of intrauterine inflammation.

Models of fetal brain injury, intrauterine inflammation, and preterm birth

Intrauterine infection and inflammation are known risk factors for brain damage in the neonate irrespective of the gestational age. Infection-induced maternal immune activation leads to a fetal inflammatory response mediated by cytokines that has been implicated in the development of not only periventricular leukomalacia and cerebral palsy but also a spectrum of neurodevelopmental disorders such as autism and schizophrenia (Behav Brain Res 2009; 204:313, Ann Neurol 2005; 57:67, Am J Obstet Gynecol 2000; 182:675). A common link among the neurobehavioral disorders associated with intrauterine inflammation appears to be the evidence for immune dysregulation in the developing brain (Behav Brain Res 2009; 204:313). The timing of the immune challenge with respect to the gestational age and neurologic development of the fetus may be crucial in the elicited response (J Neurosci 2006; 26:4752). Studies involving animal models of maternal inflammation serve a key role in elucidation of mechanisms involved in fetal brain injury associated with exposure to the maternal milieu. These animal models have been shown to result in fetal microglial activation, neurotoxicity as well motor deficits and behavioral abnormalities in the offspring (J Neurosci 2006; 26:4752, J Neurosci Res 2010; 88:172, Am J Obstet Gynecol 2009; 201:279, Am J Obstet Gynecol 2008; 199:651). A better understanding of the mechanisms of perinatal brain injury will allow discoveries of novel neuroprotective agents, better outcomes following preterm birth and stratification of fetuses and neonates for therapies in cases of preterm birth, preterm premature rupture of membranes, and chorioamnionitis.

Prophylactic administration of melatonin to the mother throughout pregnancy can protect against oxidative cerebral damage in neonatal rats

OBJECTIVE

The purpose of this study was to investigate whether prophylactic administration of melatonin to the mother throughout pregnancy could protect against ischemia/reperfusion (I/R)-induced oxidative brain damage in neonatal rats.

METHODS

The utero-ovarian arteries were occluded bilaterally for 30 min in female Wistar rats on day 16 of pregnancy to induce fetal ischemia. Reperfusion was achieved by releasing the occlusion and restoring circulation. A sham operation was performed in control rats. Melatonin solution or vehicle alone was administrated orally throughout pregnancy. We collected brain mitochondria from neonatal rats, evaluated mitochondrial structure by electron microscopy, and measured the respiratory control index (RCI) as an indicator of mitochondrial respiratory activity as well as the concentration of thiobarbituric acid-reactive substances (TBARS), a marker of oxidative stress. Histological analysis was performed at the Cornu Ammonis 1 (CA1) and Cornu Ammonis 3 (CA3) regions of the hippocampus.

RESULTS

I/R significantly reduced the RCI and significantly elevated the concentration of TBARS. Melatonin treatment reversed these effects, resulting in values similar to that in untreated, sham-ischemic animals. Electron microscopic evaluation showed that the number of intact mitochondria decreased in the I/R group, while melatonin treatment preserved them. Histological analysis revealed a decrease in the ratio of normal to whole pyramidal cell number in the CA1 and CA3 regions in the I/R group. While melatonin administration protected against degeneration.

CONCLUSIONS

These results indicate that prophylactic administration of melatonin to the mother throughout pregnancy may prevent I/R-induced oxidative brain damage in neonatal rats.

Magnetic resonance imaging demonstrates long-term changes in brain structure in children born preterm and exposed to chorioamnionitis

OBJECTIVE

We sought to determine if children born preterm and exposed to chorioamnionitis have differences in brain structure measured at 6-10 years of age using magnetic resonance imaging (MRI).

STUDY DESIGN

Structural MRI was performed with 11 preterm children (8.5 ± 1.7 years) with chorioamnionitis and 16 preterm children (8.7 ± 1.4 years) without chorioamnionitis. Cortical surface reconstruction and volumetric segmentation were performed with FreeSurfer image analysis software. Subcortical structures were analyzed using multivariate analysis.

RESULTS

Widespread regional differences in cortical thickness were observed. With chorioamnionitis, the frontal and temporal lobes were primarily affected by decreased cortical thickness, and the limbic, parietal, and occipital lobes were primarily affected by increased cortical thickness when compared to the comparison group. Subcortical differences were observed in the hippocampus and lateral ventricle.

CONCLUSION

Using MRI, chorioamnionitis is associated with longterm widespread regional effects on brain development in children born prematurely. Our study is limited by its small sample size.

Early neonatal intensive care unit therapy improves predictive power for the outcomes of ventilated extremely low birth weight infants

OBJECTIVE

To assess the predictive value of early therapy for ventilated extremely low birth weight (ELBW) infants beyond information available at delivery.

STUDY DESIGN

Prospective, single-center cohort analysis of 177 ventilated ELBW infants. We collected information known at delivery (gestational age, birth weight, singleton, sex, antenatal steroids) and additional information while infants were mechanically ventilated (head ultrasound scanning, clinician intuitions of death before discharge). An adverse outcome was defined as mortality or Bayley Mental Developmental Index or Psychomotor Developmental Index <70 at 2 years. We compared the predictive ability of clinical variables separately, in combination, and in addition to information available at delivery.

RESULTS

A total of 77% of infants survived to follow-up; 56% of survivors had Bayley Mental Developmental Index and Psychomotor Developmental Index ≥ 70. A total of 95% of infants with both abnormal head ultrasound scanning results and predicted death before discharge had an adverse outcome, independent of gestational age. Conversely, 40% of infants with normal head ultrasound scanning results and no predicted death before discharge had an adverse outcome, independent of gestational age. After adjusting for variables known at birth, predicted death before discharge and abnormal head ultrasound scanning results added significantly to the ability to predict outcomes.

CONCLUSION

Information gained early in the neonatal intensive care unit improves prediction of mortality or neurodevelopmental impairment in ventilated ELBW infants beyond information available in the delivery room.

The role of inflammation and infection in preterm birth

Much emphasis in recent decades has been devoted to inflammation and infection as a premier causal mechanism of preterm birth. This article explores the epidemiologic, clinical, and animal data that exist to support this conceptual paradigm as well as proposed mechanisms through which to potentially mitigate the adversity of prematurity. Truly successful interventions are not likely to occur until the pathogenesis of preterm birth and the role of inflammation in causing not only parturition but also fetal and neonatal injury is fully elucidated.

Serial ultrasonographic observation of bilateral thalami in low birth weight infants with periventricular leukomalacia

Periventricular leukomalacia is a major form of neuropathology in preterm infants that is associated with adverse motor and cognitive outcomes. The volume of periventricular white matter and corpus callosum has been reported to be diminished in infants with PVL, and the degree of the volume loss is correlated with the severity of neurological impairment. The thalamic index was calculated from the length, height, width of the thalamus, and thalamic volume was calculated using the formula for an ovoid in 62 low birth weight infants with gestational ages of 24-35weeks, 51 control infants (cerebral palsy, 1 case), and 11 infants diagnosed with PVL (cerebral palsy, 7 cases) at postnatal days0-70. The indices of the right thalamus were lower in infants with PVL than in control infants from day0 to day70, and there were significant differences on days 21, 28, 35, 42, 49, 56, 63, and 70. The indices of the left thalamus were lower in infants with PVL than in control infants from day0 to day70, and there were significant differences on days 21, 28, 35, 42, 49, 56, 63, and 70. The results of the present study suggest that the volume of the thalami is reduced and that thalamic injury is associated with white matter lesions in infants with PVL.

Influence of premature rupture of membrane on the cerebral blood flow in low-birth-weight infant after the delivery

Cerebral white matter injury, usually called periventricular leukomalacia (PVL), is the most common form of injury to preterm infants that is associated with adverse motor and cognitive outcomes. Intrauterine infection may be an important etiological factor in PVL, and premature rupture of the membranes (PROM) can be identified antepartum. In order to investigate the pathophysiology of cerebral white matter injury induced by PROM, the cerebral blood flow (CBF) of the internal carotid artery and the vertebral artery was measured by neck ultrasonography. The CBF was determined in 84 low-birth-weight infants with gestational ages ranging from 24 to 35 weeks, including 71 infants without PROM and 13 infants with PROM. The mean blood flow velocity and diameter of each vessel were measured on postnatal days 0-70. The intravascular flow volume was determined by calculating the mean blood flow velocity and the cross-sectional area. The mean blood pressures were recorded, and the ejection fraction was determined. The total cerebral blood flow (CBF) was significantly lower in infants with PROM than in infants without PROM from day 10 to day 70. The ejection fraction was significantly higher in infants with PROM than in infants without PROM on days 0, 5, 10, 21, and 42. There was no difference in the mean blood pressure between infants with PROM and infants without PROM. The results of the present study suggest that PROM may decrease cerebral blood flow after the birth.

Obstetric aspects of hypoxic ischemic encephalopathy

Hypoxic ischemic encephalopathy (HIE) describes neonatal encephalopathy that is caused by intrapartum asphyxia and it can result in the long term sequelae of cerebral palsy which is a major cause of disability. The incidence of cerebral palsy has not changed over the last few decades and the challenge to obstetricians remains how best to recognise those babies at risk of this intrapartum insult both before and during labour. Many associations and risk factors are unavoidable or unrecognisable, and others are fairly common and associated with poor predictive value. Intrapartum fetal heart monitoring remains the main focus of attention but how this is best achieved is still the subject of research. Computerised decision support systems built into fetal heart rate monitoring and non-invasive fetal ECG signal pick-up are currently being explored.

Periventricular leukomalacia and placental histopathologic abnormalities

OBJECTIVE

To estimate whether there are placental histopathologic abnormalities associated with neonatal periventricular leukomalacia (PVL), a major precursor of cerebral palsy.

METHODS

This is a case-control study of 167 neonates born between 23 and 34 weeks of gestation diagnosed with PVL by head ultrasonography within 6 weeks of birth, and 167 control neonates without neurologic morbidity matched by gestational age. Placentas for both case neonates and control neonates were reviewed by two perinatal pathologists who were blinded to neonatal course.

RESULTS

Neonates with PVL were significantly more likely to have positive neonatal blood (28.7%, 16.8%, P=.001) and cerebrospinal fluid (14.4%, 4.8%, P=.007) cultures. The ratio of placental weight to birth weight did not differ between groups, but neonates with PVL had significantly more chronic diffuse capsular deciduitis (20.4%, 10.8%, P=.02) and capsular decidual plasma cells (8.4%, 2.4%, P=.02). Conditional logistic regression adjusting for birth weight and the presence of multiple gestation in the identification of PVL showed a significant increase for diffuse capsular deciduitis (P=.02) and capsular decidual plasma cells (P=.03).

CONCLUSION

Periventricular leukomalacia has a significant but weak association with chronic diffuse capsular deciduitis and the presence of capsular decidual plasma cells, evidence of chronic infection but not histologic acute chorioamnionitis.

LEVEL OF EVIDENCE

II.

TNF-alpha system response in a rat model of very preterm brain injuries induced by lipopolysaccharide and/or hypoxia-ischemia

OBJECTIVE

The aim of this study was to determine, with the use of a rat model, the expression of tumor necrosis factor (TNF)-alpha, its receptors, and TNF-alpha-converting enzyme in perinatal brain lesions of early premature neonates.

STUDY DESIGN

Lipopolysaccharide (LPS) was injected intraperitoneally in pregnant rats at the end of gestation. At postnatal day 1, the right carotid artery was ligated and followed by exposure to hypoxia. Forebrains (n = 220) were collected to study the TNF-alpha system.

RESULTS

LPS alone or combined with hypoxia-ischemia (HI) led to a slight decrease of intracerebral TNF-alpha, whereas sole HI induced no variation. TNF-alpha-converting enzyme followed the same pattern of expression as TNF-alpha. TNF receptor 1 was up-regulated in forebrains that were submitted to LPS alone or combined with HI. No variation was observed in TNF receptor 2 expression.

CONCLUSION

The minimal expression of the TNF-alpha system that we observed may indicate that this pathway is not central in the pathogenesis of brain lesions in early premature neonates.

Chorioamnionitis and brain damage in the preterm newborn

AIM

To evaluate the association between histological chorioamnionitis and brain damage (intraventricular hemorrhage and cystic periventricular leukomalacia) in the preterm newborn.

METHODS

This was a retrospective study on neonates born at less than 34 weeks gestational age, and their respective mothers, at three tertiary medical centers in the north of Portugal, from January 2001 to December 2002.

RESULTS

The study included 452 newborns (235 male/217 female; birth weight 1440 (515-2620) grams; gestational age 31 (23-33) weeks), 125 from mothers whose placenta showed signs of chorioamnionitis and 327 from mothers without the condition. The association between histological chorioamnionitis and: (1) intraventricular hemorrhage grades I-IV was OR 1.43 (95% CI 0.49-3.94); (2) intraventricular hemorrhage grades III and IV was OR 2.49 (95% CI 1.20-5.11); (3) cystic periventricular leukomalacia was OR 3.02 (95% CI 1.50-6.07). The association, adjusted for birth weight and gestational age, between chorioamnionitis and: (1) intraventricular hemorrhage grades III and IV was OR 0.94 (95% CI 0.39-2.28); (2) cystic periventricular leukomalacia was OR 1.94 (95% CI 1.03-4.61). The association between histological chorioamnionitis with funisitis and/or vasculitis and: (1) intraventricular hemorrhage grades I to IV was OR 1.27 (95% CI 0.52-3.10); (2) cystic periventricular leukomalacia was OR 2.08 (95% CI 0.72-5.98).

CONCLUSION

This study confirms the association between histological chorioamnionitis and cystic periventricular leukomalacia, but was unable to confirm the association between histological chorioamnionitis and intraventricular hemorrhage.

Cystic periventricular leukomalacia in preterm infants: an analysis of obstetric risk factors

OBJECTIVE

To identify obstetric risk factors and to elucidate the effect of prolonged rupture of the membranes on the development of cystic periventricular leukomalacia (PVL) in preterm infants.

METHODS

A retrospective case-control study of 95 preterm infants with the diagnosis of PVL and 245 healthy controls matched for gestational age. A total of 52 antenatal, intrapartum and neonatal characteristics were studied by univariate methods and logistic regression.

RESULTS

Preterm premature rupture of membranes (PPROM) (odds ratio 2.1 [95% CI 1.3-3.4], P=.003), gestational age at PPROM (P=.025), prolonged rupture of membranes (P<.0001), administration of tocolytic agents (1.8 [1.1-3.0], P=.019) and antibiotics (1.9 [1.2-3.1], P=.008) were associated with PVL. The use of tocolytic agents >24 h (P=.008), prolonged latency between the increase in maternal leukocyte count and birth (P=.034), spontaneous onset of labor (1.8 [1.0-2.9], P=.026), vaginal delivery (1.7 [1.1-2.8], P=.029) and male gender (1.5 [1.0-2.0], P=.04) were found more frequently in PVL cases. Preeclampsia (0.4 [0.1-0.9], P=.034), hypertension at booking (P=.009), sonographic IUGR (P=.020), abnormal blood flow of the umbilical artery (P=.032) and cesarean section without labor (0.5 [0.3-0.8], P=.006) were found less frequently. In logistic regression analysis, prolonged rupture of the membranes (P=.748), preeclampsia (P=.973), the use of antibiotics (P=.617) and beta-sympathomimetic tocolytic agents (P=.563) lost statistical significance, whereas birth weight (P=.036) became significant.

CONCLUSION

PPROM and prolonged rupture of the membranes may provoke adverse effects on the neurodevelopmental outcome of the preterm fetus. These findings may have implications on the obstetric management of PPROM beyond 30 weeks of gestation. Cesarean section without labor was less likely associated with the diagnosis of PVL.

Late circulatory dysfunction and decreased cerebral blood flow volume in infants with periventricular leukomalacia

Periventricular leukomalacia is a major neuropathology in preterm infants associated with adverse motor and cognitive outcome. The cerebral blood flow volume of the internal carotid artery and the vertebral artery was measured by ultrasonography at the neck in 36 low-birth-weight infants with gestational age of 25-34 weeks in order to investigate the pathophysiology of cerebral white-matter injury: 30 infants, normal and 6 infants, diagnosed as PVL. The mean blood flow velocity and diameter of each vessel were measured at postnatal days from day 0 to day 70. The intravascular flow volume was determined by calculating the mean blood flow velocity and the cross-sectional area. The mean blood pressures were recorded and PaCO(2) was determined. The total blood flow volume was significantly lower in infants with PVL than in normal infants on days 0, 1, 21, 28, 35, 42, and 63. The mean blood pressure was significantly lower in infants with PVL than in normal infants on days 7, 14, 21, 28, and 42. We suggest that the total cerebral blood supply is decreased in cases of PVL in the few days after birth and from day 21 to day 42. The results of the present study suggest that a dip in the blood flow volume in the few days after birth might result in subsequent PVL.

Relationships between umbilical cord arterial blood pH levels at delivery and Bayley Psychomotor Development Index scores in early childhood

AIMS

To correlate data on umbilical cord arterial blood pH (pHa) levels obtained at delivery with subsequent Bayley Psychomotor Development (PDI) scores determined on the same cohort of children at age 18 months.

METHODS

At delivery, we obtained umbilical cord bloods for pHa levels along with other biological parameters. Following the birth cohort prospectively, at age 18 months we did a comprehensive, blinded neurodevelopmental examination to determine a PDI score for each child.

RESULTS

Over the broad range of umbilical cord arterial blood pH levels from 7.03 to 7.52, no statistically significant correlation (Pearson correlation coefficient, -0.016, P=0.88) was found between pHa at delivery and PDI scores at age 18 months. To study our finding in greater detail, we formed a subset of the data consisting only of lower pHa levels at delivery (defined as <or=7.20) and subsequent PDI scores. In this data subset, we again found that no significant relationship existed (Pearson correlation coefficient, +0.003, P=0.99).

CONCLUSIONS

Our findings are consistent with the evolving hypothesis that adverse neurological outcomes in children often have etiologies other than intrapartum fetal acidemia.

Neuregulin-1: a potential endogenous protector in perinatal brain white matter damage

Brain white matter damage, an important antecedent of long-term disabilities among preterm infants, has both endogenous and exogenous components. One of the endogenous components is the paucity of developmentally regulated protectors. Here we expand on this component, discussing the potential roles of one putative protector, neuregulin (NRG)-1, in brain development and damage. We outline how NRG-1 might be involved in perinatal brain damage pathomechanisms and suggest that NRG-1 might be one target for intervention.

Motor development and sleep, play, and feeding positions in very-low-birthweight infants with and without white matter disease

We investigated the association of infants' sleep and awake positioning with motor milestone acquisition as measured by the Alberta Infant Motor Scale (AIMS). Participants were 30 very-low-birthweight (VLBW) infants with preterm white matter disease (PTWMD; 21 males, nine females; mean birthweight [BW] 1,129 g [SD 338]; mean gestational age [GA] 28 wks [SD 2.44]); 21 VLBW infants without preterm WMD (PT; 13 males, eight females; mean BW 1,107 g [SD 370]; mean GA 28.05 wks [SD 2.21]); and 17 term infants (Term; seven males, 10 females; mean BW 3,565 g [SD 382]; mean GA 40 wks [SD 1.31]). Testing occurred at 1, 5, and 9 months of age (corrected for prematurity). Preferred positions during sleeping, playing, and feeding were obtained through parent interview. These positions and group were the independent variables. Prone sleeping was significantly and positively associated with motor development at all ages (1 mo: p=0.005; 5 mo: p=0.011; 9 mo: p=0.040). At 5 months, prone sleeping and playing were significantly and positively associated with AIMS scores (prone sleeping, p=0.016; prone playing, p=0.047). However, group was negatively associated with preterm white matter disease, with the PTWMD group having significantly lower AIMS scores than the Term group (p=0.029). At 9 months, sitting playing and group membership were significantly associated with AIMS scores (sitting playing, p=0.005; group, p=0.012). Prone positioning should be encouraged for awake time, particularly for infants with preterm white matter disease.

The fetal inflammatory response syndrome

The fetal inflammatory response syndrome (FIRS) is a condition characterized by systemic inflammation and an elevation of fetal plasma interleukin-6. This syndrome has been observed in fetuses with preterm labor with intact membranes, preterm prelabor rupture of the membranes, and also fetal viral infections such as cytomegalovirus. FIRS is a risk factor for short-term perinatal morbidity and mortality after adjustment for gestational age at delivery and also for the development of long-term sequelae such as bronchopulmonary dysplasia and brain injury. Multiorgan involvement in FIRS has been demonstrated in the hematopoietic system, thymus, adrenal glands, skin, kidneys, heart, lung, and brain. This article reviews the fetal systemic inflammatory response as a mechanism of disease. Potential interventions to control an exaggerated inflammatory response in utero are also described.

Perinatal brain damage causation

The search for causes of perinatal brain damage needs a solid theoretical foundation. Current theory apparently does not offer a unanimously accepted view of what constitutes a cause, and how it can be identified. We discuss nine potential theoretical misconceptions: (1) too narrow a view of what is a cause (causal production vs. facilitation), (2) extrapolating from possibility to fact (potential vs. factual causation), (3) if X, then invariably Y (determinism vs. probabilism), (4) co-occurrence in individuals vs. association in populations, (5) one cause is all that is needed (single cause attribution vs. multicausal constellations), (6) drawing causal inferences from very small numbers of observations (the tendency to generalize), (7) unstated causal inferences, (8) ignoring heterogeneity, and (9) failing to consider alternative explanations for what is observed. We hope that our critical discussion will contribute to fruitful research and help reduce the burden of perinatal brain damage.

Maternal plasma interleukin-6, interleukin-1beta and C-reactive protein as indicators of tocolysis failure and neonatal outcome after preterm delivery

OBJECTIVE

To investigate whether maternal serum interleukin-6 (IL-6), interleukin-1beta (IL-1beta) and high sensitive C-reactive protein (CRP) could be used as markers of tocolysis failure and adverse neonatal outcome in pregnancies with preterm labor (PL).

METHODS

Forty-seven maternal blood samples taken because of PL at admission and delivery were analyzed. Control samples were taken from 20 gravidas with normal pregnancies. Differences in interleukins and CRP levels with or without chorioamnionitis, connatal infection or periventricular leukomalacia (PVL) were analyzed. Cut-off values were estimated for prediction of tocolysis failure and adverse neonatal outcome.

RESULTS

All three parameters were significantly higher in patients delivering prematurely than in patients delivering at term. All three parameters were significantly higher with than without histologic chorioamnionitis (p < 0.001), with than without connatal infection (p < 0.01), with than without PVL (p < 0.01 for IL-6 and IL-1beta, p < 0.05 for CRP), and in pregnancies with preterm premature rupture of membranes (PPROM) delivered within 48 hours compared to those more prolonged (p < 0.01). Choosing 50.9 pg/mL of IL-6 and a CRP of 19.7 as cut-offs in maternal blood admission concentrations for neonatal PVL, resulted in sensitivity of 81% and specificity of 91% and sensitivity of 91% and specificity of 81%, respectively. At respective maternal blood admission cut-off levels of 27.8 pg/mL of IL-6 and 8.9 of CRP, both parameters were effective predictors of connatal infection.

CONCLUSIONS

Maternal blood IL-6 and CRP could become useful in predicting tocolysis failure and intrauterine treat for the fetus.

N-acetylcysteine reduces lipopolysaccharide-sensitized hypoxic-ischemic brain injury

OBJECTIVE

Maternal inflammation/infection alone or in combination with birth asphyxia increases the risk for perinatal brain injury. Free radicals are implicated as major mediators of inflammation and hypoxia-ischemia (HI)-induced perinatal brain injury. This study evaluated the neuroprotective efficacy of a scavenging agent, N-acetylcysteine (NAC), in a clinically relevant model.

METHODS

Lipopolysaccharide (LPS)-sensitized HI brain injury was induced in 8-day-old neonatal rats. NAC was administered in multiple doses, and brain injury was evaluated at 7 days after HI.

RESULTS

NAC (200mg/kg) provided marked neuroprotection with up to 78% reduction of brain injury in the pre+post-HI treatment group and 41% in the early (0 hour) post-HI treatment group, which was much more pronounced protection than another free radical scavenger, melatonin. Protection by NAC was associated with the following factors: (1) reduced isoprostane activation and nitrotyrosine formation; (2) increased levels of the antioxidants glutathione, thioredoxin-2, and (3) inhibition of caspase-3, calpain, and caspase-1 activation.

INTERPRETATION

NAC provides substantial neuroprotection against brain injury in a model that combines infection/inflammation and HI. Protection by NAC was associated with improvement of the redox state and inhibition of apoptosis, suggesting that these events play critical roles in the development of lipopolysaccharide-sensitized HI brain injury.

Survival and major neurodevelopmental impairment in extremely low gestational age newborns born 1990-2000: a retrospective cohort study

Background

It is important to determine if rates of survival and major neurodevelopmental impairment in extremely low gestational age newborns (ELGANs; infants born at 23–27 weeks gestation) are changing over time.

Methods

Study infants were born at 23 to 27 weeks of gestation without congenital anomalies at a tertiary medical center between July 1, 1990 and June 30, 2000, to mothers residing in a thirteen-county region in North Carolina. Outcomes at one year adjusted age were compared for two epochs of birth: epoch 1, July 1, 1990 to June 30, 1995; epoch 2, July 1, 1995 to June 30, 2000. Major neurodevelopmental impairment was defined as cerebral palsy, Bayley Scales of Infant Development Mental Developmental Index more than two standard deviations below the mean, or blindness.

Results

Survival of ELGANs, as a percentage of live births, was 67% [95% confidence interval: (61, 72)] in epoch 1 and 71% (65, 75) in epoch 2. Major neurodevelopmental impairment was present in 20% (15, 27) of survivors in epoch 1 and 14% (10, 20) in epoch 2. When adjusted for gestational age, survival increased [odds ratio 1.5 (1.0, 2.2), p = .03] and major neurodevelopmental impairment decreased [odds ratio 0.54 (0.31, 0.93), p = .02] from epoch 1 to epoch 2.

Conclusion

The probability of survival increased while that of major neurodevelopmental impairment decreased during the 1990's in this regionally based sample of ELGANs.

Does peripartum infection increase the incidence of cerebral palsy in extremely low birthweight infants?

OBJECTIVES

This study was undertaken to determine the perinatal predictors of cerebral palsy in extremely low birthweight infants (<1000 g).

STUDY DESIGN

A case control study of infants with birthweight of less than 1000 g (19 with cerebral palsy and 38 controls) who survived beyond 18-22 months of corrected age was performed. Outcome variables included maternal demographics, obstetric complications, and neonatal outcome (gestational age at delivery, birthweight, Apgar scores, intrauterine growth restriction, respiratory distress syndrome, intraventricular hemorrhage, and neonatal sepsis). Data analysis consisted of t tests, chi2, and analysis of variance when appropriate.

RESULTS

There were no significant differences between cerebral palsy and control groups with regard to mode of delivery, Apgar scores, preeclampsia, antenatal vaginal bleeding, or the use of magnesium sulfate. However, male gender (odds ratio 3.70; 95% CI 1.05-12.5), primigravid status (odds ratio 5.52; 95% CI 1.67-18.3), early neonatal sepsis (odds ratio 12.9; 95% CI 2.94-57.2) and chorioamnionitis, both clinical and histologic (odds ratio 3.71; 95% CI 1.16-11.9) were significantly associated with the development of cerebral palsy. The strong association between cerebral palsy and chorioamnionitis, as well as early neonatal sepsis, remain significant after adjustment for primigravid status and male gender.

CONCLUSION

In extremely low birthweight infants, cerebral palsy was strongly associated with chorioamnionitis, early neonatal sepsis, male gender, and primigravid status.

MATERNAL TEMPERATURE IN LABOUR

In this review, we are concerned primarily with pyrexia (hyperthermia; increased maternal temperature in labour) as hypothermia is rare and usually iatrogenic (as in hypothermia for cardiac bypass surgery). We start by reviewing the factors determining maternal temperature, and how it can be measured. We move on to the effects of the commonest cause of maternal pyrexia in labour in modern obstetric practice in developed countries, epidural anaesthesia. We then discuss the most feared cause of maternal pyrexia in labour, chorioamnionitis.