Hypoxic/ischemic and infectious events have cumulative effects on the risk of cerebral palsy in very-low-birth-weight preterm infants

Neuroserpin normalization by mesenchymal stem cell therapy after encephalopathy of prematurity in neonatal rats

BACKGROUND

Hypoxic-ischemia (HI), infection/inflammation and reperfusion injury are pathogenic factors of encephalopathy of prematurity, which involves maturational/neurotrophic disturbances in oligodendrocyte progenitor cells (OPC) and neurons/axons. Mesenchymal stem cells (MSCs) might facilitate neuroserpin production, which is neurotrophic for OPC/neurons. This study investigated MSC effects on developmental disturbances after lipopolysaccharide (LPS)-sensitized HI/reperfusion (LHIR) injury and the relation to neuroserpin expression.

METHODS

Postnatal day 2 (P2) rat pups received intraperitoneal LPS (5 µg/kg) injection followed by HI (unilateral common-carotid-artery ligation and 6.5% oxygen exposure for 90 min) and post-HI reperfusion (release of ligation). MSCs (5 × 104 cells) were injected into the left lateral ventricle at 24 h post-LHIR. Neurological tests and brain tissue examinations were performed between P5 and P56.

RESULTS

After LHIR injury, MSC therapy significantly reduced cell death in subplate neurons, attenuated axonal damage, and facilitated synaptophysin synthesis in the cortex. It also alleviated OPC maturation arrest and preserved the complexity of myelinated axons in the white matter, leading to cognitive, motor and behavioral functional improvements. These beneficial effects were linked to restored neuroserpin expression in subplate neurons.

CONCLUSIONS

MSC therapy ameliorated developmental disturbances after LHIR injury through protection of neuroserpin expression, serving as a promising approach for treating encephalopathy of prematurity.

IMPACT

Neuroserpin is secreted by subplate neurons and may regulate the development of neurons and oligodendrocyte-axon contact for myelination in the premature brain. LPS-sensitized hypoxic-ischemia/reperfusion (LHIR) injury caused the developmental disturbances of neurons/axons and oligodendrocytes, and lowered neuroserpin levels in a neonatal rat model simulating encephalopathy of prematurity. Mesenchymal stem cell therapy alleviated the developmental disturbances after LHIR injury through protection of neuroserpin expression in subplate neurons, offering a new perspective on potential treatment for encephalopathy of prematurity.

Human chorionic gonadotropin decreases cerebral cystic encephalomalacia and parvalbumin interneuron degeneration in a pro-inflammatory model of mouse neonatal hypoxia-ischemia

The pregnancy hormone, human chorionic gonadotropin (hCG) is an immunoregulatory and neurotrophic glycoprotein of potential clinical utility in the neonate at risk for cerebral injury. Despite its well-known role in its ability to modulate the innate immune response during pregnancy, hCG has not been demonstrated to affect the pro-degenerative actions of inflammation in neonatal hypoxia-ischemia (HI). Here we utilize a neonatal mouse model of mild HI combined with intraperitoneal administration of lipopolysaccharide (LPS) to evaluate the neuroprotective actions of hCG in the setting of endotoxin-mediated systemic inflammation. Intraperitoneal treatment of hCG shortly prior to LPS injection significantly decreased tissue loss and cystic degeneration in the hippocampal and cerebral cortex in the term-equivalent neonatal mouse exposed to mild HI. Noting that parvalbumin immunoreactive interneurons have been broadly implicated in neurodevelopmental disorders, it is notable that hCG significantly improved the injury-mediated reduction of these neurons in the cerebral cortex, striatum and hippocampus. The above findings were associated with a decrease in the amount of Iba1 immunoreactive microglia in most of these brain regions. These observations implicate hCG as an agent capable of improving the neurological morbidity associated with peripheral inflammation in the neonate affected by HI. Future preclinical studies should aim at demonstrating added neuroprotective benefit by hCG in the context of therapeutic hypothermia and further exploring the mechanisms responsible for this effect. This research is likely to advance the therapeutic role of gonadotropins as a treatment for neonates with neonatal brain injury.

Preterm birth and small for gestational age potentiate the association between maternal hypertensive pregnancy and childhood autism spectrum disorder

Children of mothers with hypertensive disorders of pregnancy (HDP) have high rates of preterm-birth (gestational age  < 37 weeks) and small-for-gestational-age (SGA), both of which are risk factors of autism spectrum disorder (ASD). This study tested the multiple-hit hypothesis that preterm-birth and SGA in the neonatal period might potentiate the antenatal impact of HDP to increase childhood ASD hazards, and HDP might not be a major contributor. The propensity-score-matched cohort enrolled 18,131 mother-child pairs with HDP and 90,655 normotensive controls between 2004 and 2011. Children with siblings born to the same mothers were excluded for analysis to reduce the potential familial-genetic influence. HDP were classified into chronic-hypertension, gestational-hypertension, preeclampsia, and preeclampsia-with-chronic-hypertension. Using the normotensive group as the reference, the associations between HDP subgroups and the cumulative ASD risks were assessed with hazard ratios, and the effects of preterm-birth and SGA on the associations were examined. The HDP group had a higher cumulative rate of ASD (1.5%) than the normotensive group (1.2%). Preterm-birth and SGA exerted moderating effects to aggravate ASD hazards in children exposed to chronic-hypertension or gestational-hypertension. None of HDP types significantly contributed to ASD after adjustments. In conclusion, antenatal HDP exposure might predispose to ASD outcome through susceptibility to the impact of preterm-birth and SGA.

Predictors of Risk for Cerebral Palsy: A Review

PURPOSE

To identify the earliest predictors of risk for diagnosis of cerebral palsy (CP).

METHODS

A comprehensive literature search was conducted using various databases. The publications were reviewed to identify risk factors for CP from conception to early infancy. Studies were critically appraised with Joanna Briggs Institute guidelines for quality appraisal and evaluated for risk of bias using the Agency for Health Care Research and Quality guidelines.

RESULTS

The initial search yielded 129 studies and 20 studies were included. Forty-seven risk factors for CP were extracted of which several were duplicate terms. The significant risk factors found to be indicative of CP were low birth weight (<1500 g), birth at less than 28 weeks of gestational age, periventricular leukomalacia, grade 3 or 4 intraventricular hemorrhage, preeclampsia, prematurity, an Apgar score of less than 4 at the first minute, birth asphyxia, preterm premature rupture of membrane, and absent fidgety movements.

CONCLUSION

Twenty-three factors were consistently reported as predictors of CP.

Impact of early screening echocardiography and targeted PDA treatment on neonatal outcomes in "22-23" week and "24-26" infants

The hemodynamically significant patent ductus arteriosus (hsPDA) is a controversial topic in neonatology, particularly among neonates at the earliest gestational ages of 22+0-23+6 weeks. There is little, to no data on the natural history or impact of the PDA in extremely preterm babies. In addition, these high-risk patients have typically been excluded from randomized clinical trials of PDA treatment. In this work, we present the impact of early hemodynamic screening (HS) of a cohort of patients born 22+0-23+6 weeks gestation who either were diagnosed with hsPDA or died in the first postnatal week as compared to a historical control (HC) cohort. We also report a comparator population of 24+0-26+6 weeks gestation. All patients in the HS epoch were evaluated between 12-18h postnatal age and treated based on disease physiology whereas the HC patients underwent echocardiography at the discretion of the clinical team. We demonstrate a two-fold reduction in the composite primary outcome of death prior to 36 weeks or severe BPD and report a lower incidence of severe intraventricular hemorrhage (n=5, 7% vs n=27, 27%), necrotizing enterocolitis (n=1, 1% vs n=11, 11%) and first-week vasopressor use (n=7, 11% vs n=40, 39%) in the HS cohort. HS was also associated with an increase in survival free of severe morbidity from the already high rate of 50% to 73% among neonates <24 weeks gestation. We present a biophysiological rationale behind the potential modulator role of hsPDA on these outcomes and review the physiology relevant to neonates born at these extremely preterm gestations. These data highlight the need for further interrogation of the biological impact of hsPDA and impact of early echocardiography directed therapy in infants born less than 24 weeks gestation.

Predictive Value of Ionized Calcium for Prognosis of Sepsis in Very Low Birth Weight Infants

Purpose

Previous studies have shown that ionized calcium (iCa) is strongly correlated with critical illnesses, including sepsis. However, there are few studies on the association of iCa levels and sepsis in very low birth weight infants (VLBWI). Therefore, the aim of this study was to investigate the role of iCa in assessing the severity of sepsis and in predicting the prognosis of sepsis in VLBWI.

Patients and Methods

249 eligible VLBWI with sepsis were included in the present study and were divided into good and poor prognosis groups according to prognosis. We collected complete laboratory and clinical data. The lowest iCa measured during the first 24h from sepsis onset was recorded, and the Pediatric Risk of Mortality (PRISM III) score was calculated for each newborn.

Results

Neonatal mortality was higher in the hypocalcemia group (32.80% vs 12.80%, P < 0.001), and iCa levels were negatively correlated with PRISM III scores (r= −0.819, P < 0.001). The result of multiple logistic regression analysis showed that iCa was an independent predictor of poor prognosis (odds ratio [OR]= 0.558, 95% confidence interval [CI], 0.406–0.768, P < 0.001). Furthermore, our data demonstrated that iCa was also an independent predictor for the occurrence of death in VLBWI with sepsis who have a poor prognosis (OR= 0.659, 95% CI, 0.445–0.977, P =0.038). ROC curve analysis showed that iCa had good discriminatory power in predicting the poor prognosis (AUC=0.739, 95% CI, 0.664–0.813, P <0.001) in VLBWI with sepsis.

Conclusion

iCa levels correlate with the severity of sepsis and can be an independent predictor of poor prognosis in VLBWI with sepsis.

Inhibiting miR-466b-5p Attenuates Neonatal White Matter Injury by Targeting Lpar1

miR-466b-5p is aberrantly upregulated in oligodendrocyte precursor cells (OPCs) after white matter injury (WMI). However, its roles in neonatal WMI pathogenesis are unknown. In this study, P3 rats were subjected to hypoxia-ischemia to establish a neonatal WMI model. A bioinformatic analysis was conducted to predict the possible target of miR-466b-5p as Lpar1. RT-PCR was performed to validate the expression of miR-466b-5p and Lpar1 mRNA. The miR-466b-5p antagomir was intracerebroventricularly administrated to inhibit miR-466b-5p; OPC differentiation, apoptosis, proliferation, and myelination were analyzed using immunofluorescence staining, western blotting, and electron microscopy. In addition, the behavioral performance of the rats was measured with the Morris water maze test. Sox10 expression and PLP trafficking were examined to elucidate the mechanism by which miR-466b-5p regulates WMI pathogenesis. We found that after inhibiting miR-466b-5p, the Edg2 protein was increased, OPC differentiation and myelinated axon formation were enhanced, and the rats' behavioral performance was improved, whereas OPC proliferation and apoptosis were not affected. Furthermore, the expression of Sox10 was promoted while PLP trafficking was attenuated after miR-466b-5p inhibition. We conclude that miR-466b-5p is involved in the regulation of WMI pathogenesis, partly through the Lpar1/Edg2/Sox10 and Lpar1/Edg2/PLP signaling pathways.

Precision of time-resolved near-infrared spectroscopy-based measurements of cerebral oxygenation in preterm infants

Significance: Time-resolved near-infrared spectroscopy (t-NIRS) is a new technology; at the moment, data on its precision in preterm infants are rare. Aim: Therefore, the aim of this study was to analyze the precision of t-NIRS-based measurements of the cerebral oxygenation in preterm infants. Approach: In 70 neonates [age: 4.7 ± 2.0 days, sex (f/m): 33/37], cerebral oxygenation ( t - rSO 2 ) was measured with an optode placed over the left frontotemporal lobe on the head, measurement duration was 1 min, and a reapplication was done for four further times (five applications). Results: Overall mean for t - rSO 2 values was 62.2 % ± 4.1 % . We found a within-patient variation for t - rSO 2 of 2.6%. Furthermore, 95% of all observed values were within a range of ± 5 % from the mean when looking on several reapplications and ± 2 % when looking within one application. Most of the variation in t - rSO 2 (60.4%) contributed to differences between patients. The remaining 39.6% of the variation was due to measurement errors and real changes of the measured signal within the neonates. Conclusions: Since within-patient variation of t - rSO 2 measures were below a clinical meaningful threshold of 5%, the measurement can be denoted as precise.

A 20-cm cut umbilical cord milking may not benefit the preterm infants < 30 week's gestation: A randomized clinical trial

BACKGROUND/PURPOSE

To evaluate whether a shorter length (20 cm) of C-UCM has potential benefits, compared to immediate cord clamping (ICC), in very preterm babies.

METHODS

Inborn preterm infants less than 30 weeks of gestational age (GA) were randomly assigned to the 20-cm C-UMC and ICC groups. The primary outcome was the need for packed red blood cell (pRBC) transfusion before the 21st day of life. The secondary outcomes were short- and long-term outcomes related to premature birth.

RESULTS

Seventy-six neonates were randomized to the two groups. GA were 27.2 ± 1.8 and 27.5 ± 1.7 weeks (p = 0.389) and birth weights were 987 ± 269 and 1023 ± 313 g (p = 0.601) in the 20-cm C-UCM and ICC groups, respectively. There was no significant difference between the groups in terms of the need for pRBC transfusion before the 21st day of life (59.4% versus 71.8%, adjusted odds ratio [aOR] 0.311, 95% confidence interval [CI] 0.090-1.079). An increased prevalence of late-onset sepsis was observed in the 20-cm C-UCM group compared to the ICC group (21.6% versus 5.1%, aOR 5.434, 95% CI 1.033-23.580). The mortality rates were 13.5% and 2.6% in the 20-cm C-UCM and ICC groups, respectively (aOR 5.339, 95% CI 0.563-50.626). The neurodevelopmental outcomes at 2 years of corrected age between the groups were also not statistically significant.

CONCLUSION

A 20-cm C-UCM showed no effect on reducing the incidence of pRBC transfusion in preterm babies with GA less than 30 weeks compared with ICC in this small-scale randomized controlled trial.

Chorioamnionitis Precipitates Perinatal Alterations of Heme-Oxygenase-1 (HO-1) Homeostasis in the Developing Rat Brain

Chorioamnionitis (CHORIO), placental insufficiency, and preterm birth are well-known antecedents of perinatal brain injury (PBI). Heme-oxygenase-1 (HO-1) is an important inducible enzyme in oxidative and inflammatory conditions. In the brain, HO-1 and the iron regulatory receptor, transferrin receptor-1 (TfR1), are known to be involved in iron homeostasis, oxidative stress, and cellular adaptive mechanisms. However, the role of HO pathway in the pathophysiology of PBI has not been previously studied. In this study, we set out to define the ontogeny of the HO pathway in the brain and determine if CHORIO changed its normal developmental regulation. We also aimed to determine the role of HO-1/TfR1 in CHORIO-induced neuroinflammation and peripheral inflammation in a clinically relevant rat model of PBI. We show that HO-1, HO-2, and TfR1 expression are developmentally regulated in the brain during the perinatal period. CHORIO elevates HO-1 and TfR1 mRNA expression in utero and in the early postnatal period and results in sustained increase in HO-1/TfR1 ratios in the brain. This is associated with neuroinflammatory and peripheral immune phenotype supported by a significant increase in brain mononuclear cells and peripheral blood double negative T cells suggesting a role of HO-1/TfR1 pathway dysregulation in CHORIO-induced neuroinflammation.

Trends in survival, neonatal morbidity and neurodevelopmental outcome of very preterm infants in Tainan, Southern Taiwan, 1995-2016

BACKGROUND

Using regression modeling analysis to investigate the breakpoints of the trends in survival-without-major-neonatal-morbidities (MNM) or -without-neurodevelopmental- impairment (NDI) by year and gestational age (GA) in preterm infants.

METHODS

We enrolled 2237 preterm infants (GA < 32 weeks) in Tainan, Taiwan. The trends in survival-without-MNM or -without-NDI by year (1995-2016) and GA (23-31 weeks), and the epochs and GA ranges with distinct changes were examined. Adjusted rate ratios (aRR) (95% confidence interval [CI]) were calculated using the rates in infants born at 23 weeks in 1995 as the reference.

RESULTS

For yearly trend, there were three epochs (1995-2000, 2001-2006, 2007-2016) with distinct changes in the rates of survival-without-MNM (aRR [95% CI] 1.07 [1.02-1.12], 1.04 [1.02-1.07], 1.02 [1.01-1.04]) and -without-NDI (1.03 [1.02-1.07], 1.02 [1.01-1.04], 1.01 [0.98-1.04]). For GA trend, the three GA ranges with different increases in the rates of survival-without-MNM were 23⁺⁰-26⁺⁶ (1.60 [1.31-1.94]), 27⁺⁰-28⁺⁶ (1.24 [1.14-1.34]) and 29⁺⁰-31⁺⁶ weeks (1.17 [1.02-1.34]), while those in the rates of survival-without-NDI were 23⁺⁰-25⁺⁶ (1.14 [1.03-1.25]), 26⁺⁰-28⁺⁶ (1.06 [1.02-1.12]) and 29⁺⁰-31⁺⁶ weeks (1.04 [1.02-1.07]). The trends in survival-without-MNM and -without-NDI increased over years in infants with GA 25-31 but not < 25 weeks.

CONCLUSION

The yearly trends in survival-without-MNM and -without-NDI had steady increases from 1995 to 2016 with distinct changes in three epochs, and the GA trends also increased with different rates per week in three GA ranges. Infants with GA < 25 weeks did not improve on the rates of survival-without-MNM or -without-NDI per year from 1995 to 2016.

Effects of Juvenile or Adolescent Working Memory Experience and Inter-Alpha Inhibitor Protein Treatment after Neonatal Hypoxia-Ischemia

Hypoxic-Ischemic (HI) brain injury in the neonate contributes to life-long cognitive impairment. Early diagnosis and therapeutic interventions are critical but limited. We previously reported in a rat model of HI two interventional approaches that improve cognitive and sensory function: administration of Inter-alpha Inhibitor Proteins (IAIPs) and early experience in an eight-arm radial water maze (RWM) task. Here, we expanded these studies to examine the combined effects of IAIPs and multiple weeks of RWM assessment beginning with juvenile or adolescent rats to evaluate optimal age windows for behavioral interventions. Subjects were divided into treatment groups; HI with vehicle, sham surgery with vehicle, and HI with IAIPs, and received either juvenile (P31 initiation) or adolescent (P52 initiation) RWM testing, followed by adult retesting. Error rates on the RWM decreased across weeks for all conditions. Whereas, HI injury impaired global performance as compared to shams. IAIP-treated HI subjects tested as juveniles made fewer errors as compared to their untreated HI counterparts. The juvenile group made significantly fewer errors on moderate demand trials and showed improved retention as compared to the adolescent group during the first week of adult retesting. Together, results support and extend our previous findings that combining behavioral and anti-inflammatory interventions in the presence of HI improves subsequent learning performance. Results further indicate sensitive periods for behavioral interventions to improve cognitive outcomes. Specifically, early life cognitive experience can improve long-term learning performance even in the presence of HI injury. Results from this study provide insight into typical brain development and the impact of developmentally targeted therapeutics and task-specific experience on subsequent cognitive processing.

Risk of cerebral palsy by gestational age among pregnancies at-risk for preterm birth

Objective: Our objective was to describe cerebral palsy (CP) incidence stratified by gestational age (GA) groups within a group at risk for spontaneous preterm birth (sPTB).Study design: This is a secondary analysis of a large study of magnesium for neuroprotection. Nonanomalous, singleton gestations complicated by preterm premature rupture of membranes (PPROM) or preterm labor (PTL) were included. Infants that developed CP were compared to controls that did not. The incidence of CP was stratified by GA groups. A logistic regression model was fit to adjust for confounders.Results: Of 1747 included pregnancies, 75 (4.3%) were affected by CP. Increasing GA at delivery was associated with lower rates of CP (RR 0.96, 95% CI 0.95-0.97; p<.0001). The most significant risk factor for CP was neonatal sepsis while the most significant protective factors were magnesium and antibiotic exposure. In the adjusted analysis, magnesium exposure (aRR 0.52, 95% CI 0.33-0.84; p = .007) and antibiotic exposure (aRR 0.52, 95% CI 0.28-0.95; p = .034) remained protective.Conclusion: The risk of CP among populations at high risk for sPTB decreases with advancing GA. While the majority of cases of CP occurred in children born <34 weeks, residual risk persisted thereafter. The effect of magnesium exposure is most pronounced before 28 weeks.

Association between bronchopulmonary dysplasia and cerebral palsy in children: a meta-analysis

OBJECTIVE

To investigate the association between bronchopulmonary dysplasia (BPD) and the risk of cerebral palsy (CP) in children.

DATA SOURCES

We used EMBASE, PubMed and Web of Science to conduct a meta-analysis of studies published before 1 September 2017, written in English whose titles or abstracts discussed an association between BPD and CP.

STUDY SELECTION

Observational studies, for example, case-control and cohort studies were included.

DATA EXTRACTION AND SYNTHESIS

All review stages were conducted by two reviewers independently. Data synthesis was undertaken via meta-analysis of available evidence.

MAIN OUTCOMES AND MEASURES

The prevalence of developing CP was measured after exposure to BPD.

RESULTS

Among 1234 initially identified studies, we selected those that addressed an association between BPD and CP according to our preselected inclusion criteria. Our meta-analysis included 11 studies. According to a random effect model, BPD was significantly associated with CP (ORs 2.10; 95% CI 1.57 to 2.82) in preterm infants. Factors explaining differences in the study results included study design, the definition of BPD, the time of diagnosis of CP and whether the studies adjusted for potential confounders.

CONCLUSION

This study suggests that BPD is a risk factor for CP. Further studies are required to confirm these results and to detect the influence of variables across studies.

The complex aetiology of cerebral palsy

Cerebral palsy (CP) is the most prevalent, severe and costly motor disability of childhood. Consequently, CP is a public health priority for prevention, but its aetiology has proved complex. In this Review, we summarize the evidence for a decline in the birth prevalence of CP in some high-income nations, describe the epidemiological evidence for risk factors, such as preterm delivery and fetal growth restriction, genetics, pregnancy infection and other exposures, and discuss the success achieved so far in prevention through the use of magnesium sulfate in preterm labour and therapeutic hypothermia for birth-asphyxiated infants. We also consider the complexities of disentangling prenatal and perinatal influences, and of establishing subtypes of the disorder, with a view to accelerating the translation of evidence into the development of strategies for the prevention of CP.

The fetus at the tipping point: modifying the outcome of fetal asphyxia

Brain injury around birth is associated with nearly half of all cases of cerebral palsy. Although brain injury is multifactorial, particularly after preterm birth, acute hypoxia-ischaemia is a major contributor to injury. It is now well established that the severity of injury after hypoxia-ischaemia is determined by a dynamic balance between injurious and protective processes. In addition, mothers who are at risk of premature delivery have high rates of diabetes and antepartum infection/inflammation and are almost universally given treatments such as antenatal glucocorticoids and magnesium sulphate to reduce the risk of death and complications after preterm birth. We review evidence that these common factors affect responses to fetal asphyxia, often in unexpected ways. For example, glucocorticoid exposure dramatically increases delayed cell loss after acute hypoxia-ischaemia, largely through secondary hyperglycaemia. This critical new information is important to understand the effects of clinical treatments of women whose fetuses are at risk of perinatal asphyxia.

Impact of Xenon on CLIC4 and Bcl-2 Expression in Lipopolysaccharide and Hypoxia-Ischemia-Induced Periventricular White Matter Damage

BACKGROUND

Premature birth is a significant health care burden. Xenon (Xe) is a general anesthetic with neuroprotective effects.

OBJECTIVES

Here, we investigate the neuroprotective role of Xe in a lipopolysaccharide (LPS)- and hypoxia-ischemia (HI)-induced white matter damage (WMD) model.

METHODS

Three-day-old Sprague-Dawley rats were randomly divided into a sham group (group A, n = 24), an LPS + HI group (group B, n = 24), and an LPS + HI + Xe group (group C, n = 72). The onset of Xe inhalation started at 0, 2, and 5 h in subgroups C1, C2, and C3, respectively. Next, we performed TUNEL and hematoxylin and eosin (HE) staining; and examined the expression of CLIC4 and Bcl-2 in brain tissues.

RESULTS

HE staining revealed distorted cytoarchitecture, tangled nerve fibers, and pyknosis in group B, while Xe treatment improved these histological alterations in the group C pups. Following LPS and HI insult, the number of apoptotic cells significantly increased in group B at 48 and 72 h (p < 0.05), and Xe significantly alleviated apoptosis (p < 0.001) at 24, 48, and 72 h, respectively. Similarly, CLIC4 mRNA expression was significantly increased in group B (p < 0.05), and Xe produced a marked reduction in CLIC4 mRNA expression in group C subgroups (p < 0.05). Western blotting demonstrated enhanced Bcl-2 expression in group C when compared to group B (p < 0.05).

CONCLUSIONS

These results demonstrate that LPS and HI successfully induced WMD, and Xe decreased neuronal apoptosis via Bcl-2- and CLIC4-mediated pathways. Moreover, the therapeutic time window of Xe extended for up to 5 h. These findings suggest that Xe can be used as a protective treatment for WMD in premature infants.

Identifying Risk Factors Shared by Bronchopulmonary Dysplasia, Severe Retinopathy, and Cystic Periventricular Leukomalacia in Very Preterm Infants for Targeted Intervention

BACKGROUND

Bronchopulmonary dysplasia (BPD), severe retinopathy of prematurity (sROP), and cystic periventricular leukomalacia (cPVL) are 3 major morbidities with long-term neurodevelopmental impairments in preterm infants.

OBJECTIVE

To investigate the strength of associations and identify key risk factors shared by BPD, sROP, and cPVL for targeted intervention.

METHODS

We studied the Taiwanese very-preterm-infant registry data on 3,507 infants admitted to neonatal intensive care units and discharged at postmenstrual age ≥36 weeks between 2008 and 2013.

RESULTS

Of 3,507 infants, 1,497 presented with at least 1 morbidity (26 [1.7%], 386 [25.8%], and 1,085 [72.5%] exhibited 3, 2, and 1 morbidities, respectively). BPD was strongly associated with sROP (odds ratio 5.93; 95% confidence interval 5.02-7.03), followed by cPVL (2.08; 1.63-2.64), but sROP and cPVL were weakly associated (1.59; 1.17-2.13). Most risk factors contributed to BPD, which shared risk factors with sROP and cPVL. A birth weight of < 1,000 g, male sex, and prolonged mechanical ventilation (MV) were shared by BPD and sROP, and chorioamnionitis, severe respiratory distress syndrome, and prolonged MV specifically contributed to BPD and cPVL. Prolonged MV was the single risk factor common to BPD, sROP, and cPVL. Avoiding prolonged MV reduced the risk of having at least 1 of the 3 morbidities by 37%.

CONCLUSIONS

BPD and sROP were most strongly associated. Most risk factors contributed to BPD, with differentially shared effects on sROP and cPVL. Prolonged MV was the only risk factor shared by all 3 morbidities, and avoiding it potentially reduced the risk of having at least 1 of them.

Isolated Cystic Periventricular Leukomalacia Differs from Cystic Periventricular Leukomalacia with Intraventricular Hemorrhage in Prevalence, Risk Factors and Outcomes in Preterm Infants

BACKGROUND

Cystic periventricular leukomalacia (cPVL) is the most severe white matter injury and is often associated with intraventricular hemorrhage (IVH) in preterm infants.

OBJECTIVE

The aim of this study was to investigate the prevalence, risk factors and neurodevelopmental outcomes of isolated cPVL and cPVL with low-grade and high-grade IVH in premature infants.

METHODS

From 2001 to 2012, 9,964 infants with <31 weeks' gestational age (GA) admitted to Taiwan hospitals were enrolled. cPVL was classified into three groups: isolated cPVL, cPVL with low-grade (I/II) IVH, and cPVL with high-grade (III) IVH.

RESULTS

Of 7,805 infants with complete ultrasound data, 286 (3.7%) had cPVL. Among the cPVL infants, 93 (32.5%) were isolated, 118 (41.3%) had low-grade IVH and 75 (26.2%) had high-grade IVH. The risk of cPVL with IVH was significantly higher among infants with <27 weeks' GA than those with ≥27 weeks' GA, in contrast to that of isolated cPVL. Using infants without cPVL and IVH as the reference group, the most significant predictor of isolated cPVL was neonatal sepsis (odds ratio 2.39; 95% confidence interval 1.52-3.77), while 5-min Apgar score <5 (2.50; 1.48-4.21) and prolonged mechanical ventilation (2.19; 1.42-3.42) were associated with cPVL with low-grade IVH, and GA <27 weeks (2.63; 1.56-4.42), pneumothorax (3.04; 1.40-6.65) and prolonged mechanical ventilation (3.36; 1.88-6.01) contributed to cPVL with high-grade IVH. cPVL infants with low-grade and high-grade IVH had a higher risk of abnormal neurodevelopmental outcomes than infants with isolated cPVL at the age of 24 months.

CONCLUSIONS

Isolated cPVL, cPVL with low-grade IVH and cPVL with high-grade IVH had different risk factors and neurodevelopmental outcomes, suggestive of different causal pathways.

SGA as a Risk Factor for Cerebral Palsy in Moderate to Late Preterm Infants: a System Review and Meta-analysis

Small for gestational age (SGA) is an established risk factor for cerebral palsy (CP) in term infants. However, there is conflicting data on the association between SGA and CP in moderate to late preterm infants. The aim of the article was to explore the relationship between SGA and CP in the moderate to late preterm infants and its strength by meta-analysis. We performed a system search in OVID (EMBASE and MEDLINE) and WANFANG from inception to May 2016. The study-specific risk estimates were pooled using the random-effect model. A total of seven studies were included in the meta-analysis, consisting of three cohort and four case-control studies. A statistically significant association was found between SGA and CP in moderate to late premature infants (OR: 2.34; 95% CI: 1.43-3.82). The association were higher in the several subgroups: 34-36 week gestational age (OR: 3.47; 95% CI: 1.29-9.31), SGA < 2SDs (OR: 3.48; 95% CI: 1.86-6.49), and malformation included in CP (OR: 3.00; 95% CI: 1.71-5.26). In moderate to late premature infants, SGA is a convenient and reliable predictor for CP. More studies are needed to explore the underlying mechanisms between SGA and CP association.

Combined damage produced by multiple mild cerebral insults assessed using MRI in neonatal rats

PURPOSE

To determine whether damage to neonatal brain is exacerbated with multiple mild cerebral insults as detected with MRI and corroborated using histology.

MATERIALS AND METHODS

The combined brain injury produced by multiple procedures was compared in neonatal rats having: Sham surgery at P5, Sham surgery at P5 plus a diffuse mild transient unilateral cerebral hypoxia ischemia (HI) at P7, HI alone, and a minor photothrombotic (PT) stroke at P5 followed by HI. MRI after the ischemic insults was followed by final histology.

RESULTS

PT produced lesions with increased T₂ and decreased apparent diffusion coefficient for water (ADC) but no significant effects of a second HI. However, near the PT lesion/parietal cortex there were patchy areas of enhanced T₂ and decreased ADC in 6/9, 3/8 and 0/8 animals in the PT+HI, Sham+HI and HI groups, respectively (P<0.05). Patches corresponded histologically to increased vacuolation and cell death and were more pronounced in the PT+HI and Sham+PT groups than the HI group.

CONCLUSION

The extent of damage produced by a minor neonatal stroke followed by a diffuse HI two days later results in heterogeneous enhancement of T₂, ADC and histological injury near the lesion. Surgical procedures including mechanical head manipulation followed by HI also produced some enhanced heterogeneity of hypoxic-ischemic injury affirming the need for sham controls.

Loss of PINK1 inhibits apoptosis by upregulating α-synuclein in inflammation-sensitized hypoxic-ischemic injury in the immature brains

The incidence of preterm birth is rising worldwide. Among preterm infants, many face a lifetime of neurologic impairments. Recent studies have revealed that systemic inflammation can sensitize the immature brain to hypoxic-ischemic (HI) injury. Therefore, it is important to identify the mechanisms involved in inflammation-sensitized HI injury in immature brains. PTEN-induced putative kinase 1 (PINK1) is a regulatory protein that is highly expressed in the brain. We have previously found that PINK1 gene knockout can protect matured brains from HI injury in postnatal day 10 mice. However, the mechanisms are unknown. In this study, we employed an inflammation-sensitized HI injury model using postnatal day 3 mice to study the roles and mechanisms that PINK1 plays in the immature brains. Lipopolysaccharide (LPS) was injected intraperitoneally into the mice before HI treatment to set up the model. We found that PINK1-knockout mice had fewer brain infarcts and less cell apoptosis than did the wild-type mice. Furthermore, we found that α-synuclein was markedly higher in the PINK1-knockout mice than in the wild-type mice, and inhibition of α-synuclein through small interfering RNA (siRNA) reversed the protective effect in the PINK1-knockout mice. Collectively, these findings indicate that loss of PINK1 plays a novel role in the protection of inflammation-sensitized HI brain damage.

Postnatal Steroids and Febrile Seizure Susceptibility in Preterm Children

OBJECTIVE

To investigate risk factors, seizure characteristics, and outcomes of febrile seizure (FS) in children born very preterm.

METHODS

This study used a prospective registry data set of 844 preterm infants (birth weight <1500 g and gestational age <32 weeks) admitted to NICUs from 2001 to 2009 in southern Taiwan. We investigated the prevalence, risks, seizure patterns, and outcomes of FS in children aged 5 years.

RESULTS

Among 575 children (follow-up rate, 85.8%) followed up for 5 years, 35 (6.1%) developed FS. The FS and non-FS groups were comparable regarding their mean gestational age, birth weight, 5-minute Apgar score <6, and prenatal and postnatal complications. No difference was observed in the use of prenatal corticosteroids between the 2 groups. The FS group had a significantly higher rate of postnatal corticosteroid treatment than the non-FS group, even after adjusting for confounding factors (odds ratio, 5.4 [95% confidence interval, 1.9-15.8]; P = .006). No differences were observed in IQs or subsequent epilepsy rates between the 2 groups. Although no difference was observed in the age of FS onset or neurodevelopmental outcomes between the 2 groups, children with FS who received postnatal corticosteroid treatment had a significantly lower mean body temperature during the first FS attack compared with those who did not receive postnatal corticosteroid treatment (38.6 ± 0.4°C vs 39.2 ± 0.6°C; P = .034).

CONCLUSIONS

Children born very preterm have a higher rate of FS, and postnatal corticosteroid treatment was associated with FS susceptibility in these children.

CXCL5 signaling is a shared pathway of neuroinflammation and blood-brain barrier injury contributing to white matter injury in the immature brain

Background

In very preterm infants, white matter injury is a prominent brain injury, and hypoxic ischemia (HI) and infection are the two primary pathogenic factors of this injury. Microglia and microvascular endothelial cells closely interact; therefore, a common signaling pathway may cause neuroinflammation and blood–brain barrier (BBB) damage after injury to the immature brain. CXC chemokine ligand 5 (CXCL5) is produced in inflammatory and endothelial cells by various organs in response to insults. CXCL5 levels markedly increased in the amniotic cavity in response to intrauterine infection and preterm birth in clinical studies. The objective of this study is to determine whether CXCL5 signaling is a shared pathway of neuroinflammation and BBB injury that contributes to white matter injury in the immature brain.

Methods

Postpartum day 2 (P2) rat pups received lipopolysaccharide (LPS) followed by 90-min HI. Immunohistochemical analyses were performed to determine microglial activation, neutrophil infiltration, BBB damage, and myelin basic protein and glial fibrillary acidic protein expression. Immunofluorescence experiments were performed to determine the cellular distribution of CXCL5. Pharmacological tests were performed to inhibit or enhance CXCL5 activity.

Results

On P2, predominant increases in microglial activation and BBB damage were observed 24 h after LPS-sensitized HI induction, and white matter injury (decreased myelination and increased astrogliosis) was observed on P12 compared with controls. Immunohistochemical analyses revealed increased CXCL5 expression in the white matter 6 and 24 h after insult. Immunofluorescence experiments revealed upregulated CXCL5 expression in the activated microglia and endothelial cells 24 h after insult. CXCL5 inhibition by SB225002, a selective nonpeptide inhibitor of CXCR2, significantly attenuated microglial activation and BBB damage, increased myelination, and reduced astrogliosis in the white matter after LPS-sensitized HI. In addition, CXCL5-sensitized HI or CXCL5 alone significantly induced BBB damage and white matter injury in association with different neuroinflammation mechanisms. CXCL5-sensitized HI-induced microglial activation and neutrophil infiltration, whereas CXCL5 alone predominately caused neutrophil infiltration.

Conclusions

CXCL5 is a potential biomarker for white matter injury in preterm infants. Pharmacological blockade of CXCL5 signaling that attenuates dysregulated neuroinflammation can be used a therapeutic strategy against white matter injury in the immature brain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-015-0474-6) contains supplementary material, which is available to authorized users.

TNFR1-JNK signaling is the shared pathway of neuroinflammation and neurovascular damage after LPS-sensitized hypoxic-ischemic injury in the immature brain

Background

Hypoxic-ischemia (HI) and inflammation are the two major pathogenic mechanisms of brain injury in very preterm infants. The neurovascular unit is the major target of HI injury in the immature brain. Systemic inflammation may worsen HI by up-regulating neuroinflammation and disrupting the blood–brain barrier (BBB). Since neurons and oligodendrocytes, microvascular endothelial cells, and microglia may closely interact with each other, there may be a common signaling pathway leading to neuroinflammation and neurovascular damage after injury in the immature brain. TNF-α is a key pro-inflammatory cytokine that acts through the TNF receptor (TNFR), and c-Jun N-terminal kinases (JNK) are important stress-responsive kinases.

Objective

To determine if TNFR1-JNK signaling is a shared pathway underlying neuroinflammation and neurovascular injury after lipopolysaccharide (LPS)-sensitized HI in the immature brain.

Methods

Postpartum (P) day-5 mice received LPS or normal saline (NS) injection before HI. Immunohistochemistry, immunoblotting and TNFR1- and TNFR2-knockout mouse pups were used to determine neuroinflammation, BBB damage, TNF-α expression, JNK activation, and cell apoptosis. The cellular distribution of p-JNK, TNFR1/TNFR2 and cleaved caspase-3 were examined using immunofluorescent staining.

Results

The LPS + HI group had significantly greater up-regulation of activated microglia, TNF-α and TNFR1 expression, and increases of BBB disruption and cleaved caspase-3 levels at 24 hours post-insult, and showed more cortical and white matter injury on P17 than the control and NS + HI groups. Cleaved caspase-3 was highly expressed in microvascular endothelial cells, neurons, and oligodendroglial precursor cells. LPS-sensitized HI also induced JNK activation and up-regulation of TNFR1 but not TNFR2 expression in the microglia, endothelial cells, neurons, and oligodendrocyte progenitors, and most of the TNFR1-positive cells co-expressed p-JNK. Etanercept (a TNF-α inhibitor) and AS601245 (a JNK inhibitor) protected against LPS-sensitized HI brain injury. The TNFR1-knockout but not TNFR2-knockout pups had significant reduction in JNK activation, attenuation of microglial activation, BBB breakdown and cleaved caspase-3 expression, and showed markedly less cortical and white matter injury than the wild-type pups after LPS-sensitized HI.

Conclusion

TNFR1-JNK signaling is the shared pathway leading to neuroinflammation and neurovascular damage after LPS-sensitized HI in the immature brain.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-014-0215-2) contains supplementary material, which is available to authorized users.