The relationship of CSF and plasma cytokine levels to cerebral white matter injury in the premature newborn

Increased PLAGL1 Gene Methylation in Cord Blood is Positively Correlated with Brain Injury in Chorioamniotic Preterm Infants

The study aims to explore the epigenetic mechanisms of neurodevelopmental impairment accompanied in chorioamniotic preterm infants. Our study included 16 full-term infants and 69 preterm infants. The methylation status of the pleomorphic adenoma gene-like 1 (PLAGL1) gene in the cord blood was determined by pyrosequencing. Brain B-ultrasonography and magnetic resonance imaging (MRI) were performed to diagnose brain injury. The activity of candidate fragments of PLAGL1 and the effect of methylation on PLAGL1 activity were evaluated by double luciferase reporter assay. The data showed that there were no differences in the methylation levels of each Cytosine-phosphate-Guanine (CpG) site of PLAGL1 between full-term and preterm infants. Within preterm infants, the methylation levels of the CpG2, CpG3, CpG4, and CpG5 sites were increased in the chorioamnionitis group compared with the no chorioamnionitis group. The areas under curves (AUCs) of the receiver operating characteristic (ROC) curves of CpG2, CpG3, CpG4, and CpG5 were 0.656, 0.653, 0.670, and 0.712, respectively. Meanwhile, the methylation level of the CpG2 site was increased in preterm babies with brain injury compared with those without brain injury, and the AUC of CpG2 was 0.648, with a sensitivity of 75.9% and a specificity of 50.0%. A double luciferase reporter assay revealed that PLAGL1 fragments had enhancer-like activity and that the methylated form of PLAGL1 weakened this activity. Thus, PLAGL1 hypermethylation in chorioamniotic preterm infants is positively correlated with brain injury. Our results suggest a potential use for PLAGL1 methylation as a biomarker in the diagnosis of brain injury.

Alpha-pinene ameliorate behavioral deficit induced by early postnatal hypoxia in the rat: study the inflammatory mechanism

Neonatal hypoxia has a negative impact on the developing brain during the sensitive period. Inflammation plays a key role in the physiological response to hypoxic stress. Considering the anti-inflammatory properties of alpha-pinene, which has received a lot of attention in recent years, in this research we focused on the impact of alpha-pinene on the behavioral responses and proinflammatory factors in rats subjected to the neonatal hypoxia. This study involved Wistar rats (7-day-old) that were divided into six experimental groups, including a control group, groups receiving different doses of alpha-pinene (5 and 10 mg/kg), a hypoxia group receiving 7% O2 and 93% N2, 90 min duration for 7 days, and groups receiving alpha-pinene 30 min before hypoxia. All injections were done intraperitoneally. The rats were evaluated for proinflammatory factors 24 h after exposure to hypoxia (PND14) and at the end of the behavioral test (PND54). The results showed that hypoxia led to decreased motor activity, coordination, and memory, as well as increased inflammation. However, the rats that received alpha-pinene showed improved behavioral responses and reduced inflammation compared to the hypoxia group (all cases p < 0.05). This suggests that alpha-pinene may have a protective effect via anti-inflammatory properties against the negative impacts of hypoxia on the developing brain.

Neurodevelopment at 24 months corrected age in extremely preterm infants treated with dexamethasone alternatives during the late postnatal period: a cohort study

The administration of dexamethasone has been associated with suboptimal neurodevelopment. We aimed to compare the development of extremely premature infants treated or not with alternatives to dexamethasone: betamethasone, hydrocortisone hemisuccinate. This retrospective cohort study included infants born before 29 weeks of gestational age, treated or not with late (day ≥ 7) postnatal steroids (betamethasone, hydrocortisone hemisuccinate). The neurodevelopment outcome was evaluated at 24 months corrected age, after adjustment on comorbidities of extreme prematurity. In order to analyse their overall development, data about growth and respiratory outcomes were collected. Among the 192 infants included, 59 (30.7%) received postnatal steroids. Suboptimal neurodevelopment concerned 37/59 (62.7%) postnatal steroid-treated and 43/133 (38.1%; p = 0.002) untreated infants. However, in multivariable analysis, only severe neonatal morbidity (p = 0.007) and male gender (p = 0.027) were associated with suboptimal neurodevelopment outcome at 24 months.  Conclusions: Betamethasone or hydrocortisone hemisuccinate treatment was not an independent risk for suboptimal neurological development, growth and respiratory outcomes assessed at 24 months corrected age in extremely premature infants.  Registration number: The study was registered on the ClinicalTrials.gov register: NCT05055193. What is Known: • Late postnatal steroids are used to treat bronchopulmonary dysplasia • Meta-analyses warned against the neurological risk of dexamethasone use during neonatal period. Early or late hydrocortisone hemisuccinate has been evaluated in multiple studies, none of which have reported an adverse effect on neurodevelopment at least to 2 years. Data about the use of betamethasone are scarce. What is New: • The risk of suboptimal neurodevelopment was higher among extremely premature infants who received postnatal steroids when compared to those who did not. • Betamethasone and hydrocortisone hemisuccinate treatment was not an independent risk factor for suboptimal neurodevelopment at 24 months corrected age.

Pro Inflammatory Cytokines Profiles of Patients With Long COVID Differ Between Variant Epochs

BACKGROUND

Over 30% of patients with COVID-19 have persistent symptoms that last beyond 30 days and referred to as Long COVID. Long COVID has been associated with a persistent elevation in peripheral cytokines including interleukin-6, interleukin-1β, and tumor necrosis factor-α. This study reports cytokine profiles of patients in our clinic across SARS-COV-2 variant epochs.

METHODS

The clinical cytokine panel was analyzed in patients with Long COVID during periods that were stratified according to variant epoch. The 4 variant epochs were defined as: (1) wild-type through alpha, (2) alpha/beta/gamma, (3) delta, and (4) omicron variants.

RESULTS

A total of 390 patients had the clinical cytokine panel performed; the median age was 48 years (IQR 38-59) and 62% were female. Distribution by variant was wild-type and alpha, 50% (n = 196); alpha/beta/gamma, 7.9% (n = 31); delta, 18% (n = 72); and omicron, 23% (n = 91). Time to cytokine panel testing was significantly longer for the earlier epochs. Tumor necrosis factor-α (P < .001) and interleukin 1β (P < .001) were significantly more elevated in the earlier epochs (median of 558 days in wild-type through Alpha epoch vs 263 days in omicron epoch, P < .001)). Nucleocapsid antibodies were consistently detected across epochs.

DISCUSSION

When stratified by variant epoch, patients with early epoch Long COVID had persistently elevated peripheral pro-inflammatory cytokine levels when compared to later epoch Long COVID. Patients with Long COVID have similar clusters of symptoms across epochs, suggesting that the underlying pathology is independent of the peripheral cytokine signature.

The association between inflammatory markers in blood and cerebrospinal fluid: a systematic review and meta-analysis

BACKGROUND

Neuroinflammatory processes have been hypothesized to play a role in the pathogenesis of psychiatric and neurological diseases. Studies on this topic often rely on analysis of inflammatory biomarkers in peripheral blood. Unfortunately, the extent to which these peripheral markers reflect inflammatory processes in the central nervous system (CNS) is unclear.

METHODS

We performed a systematic review and found 29 studies examining the association between inflammatory marker levels in blood and cerebrospinal (CSF) samples. We performed a random effects meta-analysis of 21 studies (pooled n = 1679 paired samples) that reported the correlation of inflammatory markers in paired blood-CSF samples.

RESULTS

A qualitative review revealed moderate to high quality of included studies with the majority of studies reporting no significant correlation of inflammatory markers between paired blood-CSF. Meta-analyses revealed a significant low pooled correlation between peripheral and CSF biomarkers (r = 0.21). Meta-analyses of individual cytokines revealed a significant pooled correlation for IL-6 (r = 0.26) and TNFα (r = 0.3) after excluding outlier studies, but not for other cytokines. Sensitivity analyses showed that correlations were highest among participants with a median age above 50 (r = 0.46) and among autoimmune disorder patients (r = 0.35).

CONCLUSION

This systematic review and meta-analysis revealed poor correlation between peripheral and central inflammatory markers in paired blood-CSF samples, with increased correlations in certain study populations. Based on the current findings, peripheral inflammatory markers are a poor reflection of the neuroinflammatory profile.

Doublecortin and Glypican-2 concentrations in the cerebrospinal fluid from infants are developmentally downregulated

OBJECTIVE

Doublecortin (DCX) and glypican-2 (GPC2) are neurodevelopmental proteins involved in the differentiation of neural stem/progenitor cells (NSPCs) to neurons, and are developmentally downregulated in neurons after birth. In this study, we investigated whether the concentrations of DCX and GPC2 in the cerebrospinal fluid (CSF) from human pediatric patients reflect this developmental process or are associated with cerebral damage or inflammatory markers.

METHODS

CSF was collected from pediatric patients requiring neurosurgical treatment. The concentrations of DCX, GPC2, neuron-specific enolase (NSE), S100 calcium-binding protein B (S100B), and cytokines (IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-13, IFN-γ, and TNF-⍺) were measured using immunoassays.

RESULTS

From March 2013 until October 2018, 63 CSF samples were collected from 38 pediatric patients (20 females; 17 patients with repeated measurements); the median term born-adjusted age was 3.27 years [Q1: 0.31, Q3: 7.72]. The median concentration of DCX was 329 pg/ml [Q1: 192.5, Q3: 1179.6] and that of GPC2 was 26 pg/ml [Q1: 13.25, Q3: 149.25]. DCX and GPC2 concentrations independently significantly associated with age, and their concentration declined with advancing age, reaching undetectable levels at 0.3 years for DCX, and plateauing at 1.5 years for GPC2. Both DCX and GPC2 associated with hydrocephalus, NSE, IL-1β, IL-2, IL-8, IL-13. No relationship was found between sex, acute infection, S100B, IL-4, IL-6, IL-10, IFN-γ, TNF-α and DCX or GPC2, respectively.

CONCLUSIONS

Concentrations of DCX and GPC2 in the CSF from pediatric patients are developmentally downregulated, with the highest concentrations measured at the earliest adjusted age, and reflect a neurodevelopmental stage rather than a particular disease state.

A Proof-of-Concept Electrochemical Skin Sensor for Simultaneous Measurement of Glial Fibrillary Acidic Protein (GFAP) and Interleukin-6 (IL-6) for Management of Traumatic Brain Injuries

This work demonstrates the use of a noninvasive, sweat-based dual biomarker electrochemical sensor for continuous, prognostic monitoring of a Traumatic Brain Injury (TBI) with the aim of enhancing patient outcomes and reducing the time to treatment after injury. A multiplexed SWEATSENSER was used for noninvasive continuous monitoring of glial fibrillary acidic protein (GFAP) and Interleukin-6 (IL-6) in a human sweat analog and in human sweat. Electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) were used to measure the sensor response. The assay chemistry was characterized using Fourier Transform Infrared Spectroscopy (FTIR). The SWEATSENSER was able to detect GFAP and IL-6 in sweat over a dynamic range of 3 log orders for GFAP and 2 log orders for IL-6. The limit of detection (LOD) for GFAP detection in the sweat analog was estimated to be 14 pg/mL using EIS and the LOD for IL-6 was estimated to be 10 pg/mL using EIS. An interference study was performed where the specific signal was significantly higher than the non-specific signal. Finally, the SWEATSENSER was able to distinguish between GFAP and IL-6 in simulated conditions of a TBI in human sweat. This work demonstrates the first proof-of-feasibility of a multiplexed TBI marker combined with cytokine and inflammatory marker detection in passively expressed sweat in a wearable form-factor that can be utilized toward better management of TBIs. This is the first step toward demonstrating a noninvasive enabling technology that can enable baseline tracking of an inflammatory response.

An integrated cytokine and kynurenine network as the basis of neuroimmune communication

Two of the molecular families closely associated with mediating communication between the brain and immune system are cytokines and the kynurenine metabolites of tryptophan. Both groups regulate neuron and glial activity in the central nervous system (CNS) and leukocyte function in the immune system, although neither group alone completely explains neuroimmune function, disease occurrence or severity. This essay suggests that the two families perform complementary functions generating an integrated network. The kynurenine pathway determines overall neuronal excitability and plasticity by modulating glutamate receptors and GPR35 activity across the CNS, and regulates general features of immune cell status, surveillance and tolerance which often involves the Aryl Hydrocarbon Receptor (AHR). Equally, cytokines and chemokines define and regulate specific populations of neurons, glia or immune system leukocytes, generating more specific responses within restricted CNS regions or leukocyte populations. In addition, as there is a much larger variety of these compounds, their homing properties enable the superimposition of dynamic variations of cell activity upon local, spatially limited, cell populations. This would in principle allow the targeting of potential treatments to restricted regions of the CNS. The proposed synergistic interface of 'tonic' kynurenine pathway affecting baseline activity and the superimposed 'phasic' cytokine system would constitute an integrated network explaining some features of neuroimmune communication. The concept would broaden the scope for the development of new treatments for disorders involving both the CNS and immune systems, with safer and more effective agents targeted to specific CNS regions.

Proteomic profiles in cerebrospinal fluid predicted death and disability in term infants with perinatal asphyxia: A pilot study

Aim

Perinatal asphyxia, resulting in hypoxic‐ischaemic encephalopathy (HIE), has been associated with high mortality rates and severe lifelong neurodevelopmental disabilities. Our aim was to study the association between the proteomic profile in cerebrospinal fluid (CSF) and the degree of HIE and long‐term outcomes.

Methods

We prospectively enrolled 18‐term born infants with HIE and 10‐term born controls between 2000 and 2004 from the Karolinska University Hospital. An antibody suspension bead array and FlexMap3D analysis was used to characterise 178 unique brain‐derived and inflammation associated proteins in their CSF.

Results

Increased CSF concentrations of several brain‐specific proteins were observed in the proteome of HIE patients compared with the controls. An upregulation of neuroinflammatory pathways was also noted and this was confirmed by pathway analysis. Principal component analysis revealed a gradient from favourable to unfavourable HIE grades and outcomes. The proteins that provided strong predictors were structural proteins, including myelin basic protein and alpha‐II spectrin. The functional proteins included energy‐related proteins like neuron‐specific enolase and synaptic regulatory proteins. Increased CSF levels of 51 proteins correlated with adverse outcomes in infants with HIE.

Conclusion

Brain‐specific proteins and neuroinflammatory mediators in CSF may predict HIE degrees and outcomes after perinatal asphyxia.

Functional status of brainstem auditory pathway in babies born below 30 week gestation with necrotizing enterocolitis

OBJECTIVE

Recent studies showed that neonatal necrotizing enterocolitis (NEC) adversely affects the brainstem auditory pathway in babies born at 30-40 week gestation. We compared the functional status of the pathway between babies born below 30 week gestation with NEC and those without NEC for any differences to understand whether NEC also affects the pathway in babies born at a smaller gestation.

METHOD

Brainstem auditory evoked response was studied at term in NEC babies born below 30 week gestation. The data obtained were compared with age-matched non-NEC babies for any abnormalities, and then compared with previously reported NEC babies born at 30-34 week gestation for any differences.

RESULTS

Although the latencies of waves I and III did not differ significantly between NEC and non-NEC babies, wave V latency in NEC babies was longer than in non-NEC babies at all click rates used. In particular, I-V interpeak interval, reflecting brainstem conduction time, in NEC babies was significant longer than in non-NEC babies. Wave V amplitude and the V/I amplitude ratios in NEC babies was smaller than in non-NEC babies at some click rates. The I-V interval in our NEC babies born below 30 week gestation was longer than in previously reported NEC babies born at 30-34 week gestation at all click rates.

CONCLUSION

NEC babies born below 30 week gestation are associated with delayed brainstem conduction time. Functional status of the brainstem auditory pathway in NEC babies born below 30 week gestation is less favorable than that in those with greater gestation.

Low-Dose Delta-9-Tetrahydrocannabinol as Beneficial Treatment for Aged APP/PS1 Mice

Studies on the effective and safe therapeutic dosage of delta-9-tetrahydrocannabinol (THC) for the treatment of Alzheimer’s disease (AD) have been sparse due to the concern about THC’s psychotropic activity. The present study focused on demonstrating the beneficial effect of low-dose THC treatment in preclinical AD models. The effect of THC on amyloid-β (Aβ) production was examined in N2a/AβPPswe cells. An in vivo study was conducted in aged APP/PS1 transgenic mice that received an intraperitoneal injection of THC at 0.02 and 0.2 mg/kg every other day for three months. The in vitro study showed that THC inhibited Aβ aggregation within a safe dose range. Results of the radial arm water maze (RAWM) test demonstrated that treatment with 0.02 and 0.2 mg/kg of THC for three months significantly improved the spatial learning performance of aged APP/PS1 mice in a dose-dependent manner. Results of protein analyses revealed that low-dose THC treatment significantly decreased the expression of Aβ oligomers, phospho-tau and total tau, and increased the expression of Aβ monomers and phospho-GSK-3β (Ser9) in the THC-treated brain tissues. In conclusion, treatment with THC at 0.2 and 0.02 mg/kg improved the spatial learning of aged APP/PS1 mice, suggesting low-dose THC is a safe and effective treatment for AD.

The cerebrospinal fluid proteome of preterm infants predicts neurodevelopmental outcome

BACKGROUND

Survival rate increases for preterm infants, but long-term neurodevelopmental outcome predictors are lacking. Our primary aim was to determine whether a specific proteomic profile in cerebrospinal fluid (CSF) of preterm infants differs from that of term infants and to identify novel biomarkers of neurodevelopmental outcome in preterm infants.

METHODS

Twenty-seven preterm infants with median gestational age 27 w + 4 d and ten full-term infants were enrolled prospectively. Protein profiling of CSF were performed utilizing an antibody suspension bead array. The relative levels of 178 unique brain derived proteins and inflammatory mediators, selected from the Human Protein Atlas, were measured.

RESULTS

The CSF protein profile of preterm infants differed from that of term infants. Increased levels of brain specific proteins that are associated with neurodevelopment and neuroinflammatory pathways made up a distinct protein profile in the preterm infants. The most significant differences were seen in proteins involved in neurodevelopmental regulation and synaptic plasticity, as well as components of the innate immune system. Several proteins correlated with favorable outcome in preterm infants at 18-24 months corrected age. Among the proteins that provided strong predictors of outcome were vascular endothelial growth factor C, Neurocan core protein and seizure protein 6, all highly important in normal brain development.

CONCLUSION

Our data suggest a vulnerability of the preterm brain to postnatal events and that alterations in protein levels may contribute to unfavorable neurodevelopmental outcome.

Is late prevention of cerebral palsy in extremely preterm infants plausible?

Preterm birth continues to be associated with neurodevelopmental problems including cerebral palsy. Cystic white matter injury is still the major neuropathology underlying cerebral palsy, affecting 1-3% of preterm infants. Although rates have gradually fallen over time, the pathogenesis and evolution of cystic white matter injury are still poorly understood. Hypoxia-ischemia (HI) remains an important contributor yet there is no established treatment to prevent injury. Clinically, serial ultrasound and magnetic resonance imaging studies typically show delayed development of cystic lesions 2 to 4 weeks after birth. This raises the important and unresolved question as to whether this represents slow evolution of injury occurring around the time of birth, or repeated injury over many weeks after birth. There is increasing evidence that tertiary injury after HI can contribute to impairment of white and grey matter maturation. In the present review, we discuss preclinical evidence that severe, cystic white matter injury can evolve for many weeks after acute HI and is associated with microglia activity. This suggests the intriguing hypothesis that the tertiary phase of injury is not as subtle as often thought and that there may be a window of therapeutic opportunity for one to two weeks after hypoxic-ischemic injury to prevent delayed cystic lesions and so further reduce the risk of cerebral palsy after preterm birth.

Effects of Prenatal Hypoxia on Nervous System Development and Related Diseases

The fetal origins of adult disease (FOAD) hypothesis, which was proposed by David Barker in the United Kingdom in the late 1980s, posited that adult chronic diseases originated from various adverse stimuli in early fetal development. FOAD is associated with a wide range of adult chronic diseases, including cardiovascular disease, cancer, type 2 diabetes and neurological disorders such as schizophrenia, depression, anxiety, and autism. Intrauterine hypoxia/prenatal hypoxia is one of the most common complications of obstetrics and could lead to alterations in brain structure and function; therefore, it is strongly associated with neurological disorders such as cognitive impairment and anxiety. However, how fetal hypoxia results in neurological disorders remains unclear. According to the existing literature, we have summarized the causes of prenatal hypoxia, the effects of prenatal hypoxia on brain development and behavioral phenotypes, and the possible molecular mechanisms.

Neurodevelopmental Outcomes at 18-24 Months of Corrected Age in Very Low Birth Weight Infants with Late-onset Sepsis

BACKGROUND

Preterm infants are prone to sepsis owing to their immature innate immunity and prolonged hospitalization. We aimed to evaluate the association between late-onset sepsis (LOS) during hospitalization and neurodevelopmental delay at 18-24 months of corrected age in very low birth weight infants (VLBWIs), and to ascertain this association when adjusted for perinatal risk factors.

METHODS

This is a population-based study of VLBWIs born at 23-32 weeks of gestation between January 2014 and December 2017 who were enrolled in the Korean Neonatal Network. Bayley scales of infant development were evaluated at 18-24 months of corrected age in 2,098 infants. To test for LOS as a risk factor for neurodevelopmental delay, multiple logistic regression was used and adjusted for parental education status and clinical variables.

RESULTS

Blood culture positive LOS was identified in 419 (20.0%) infants. Cognitive and motor delays were found in 392 (18.7%) and 347 (16.5%) infants, respectively. When multivariate analysis was performed, LOS had a significant association with cognitive delay (odds ratio, 1.48; 95% confidence interval, 1.02-2.16), but no association with motor delay in VLBWIs. Both delays were significantly more frequent in cases of intraventricular hemorrhage (IVH) ≥ grade 3, periventricular leukomalacia (PVL), and intrauterine growth restriction (IUGR) and duration of mechanical ventilation. Male sex and necrotizing enterocolitis ≥ grade 2 had an effect on motor delay, whereas paternal college graduation affected cognitive delay.

CONCLUSION

In VLBWIs with LOS, there is a heightened risk of cognitive delays at 18-24 months of corrected age. Brain injury, such as severe IVH and PVL, duration of mechanical ventilation, and IUGR, were also associated with cognitive and motor delays.

Potential biomarkers of childhood brain tumor identified by proteomics of cerebrospinal fluid from extraventricular drainage (EVD)

Brain tumors are the most common solid tumors in childhood. There is the need for biomarkers of residual disease, therapy response and recurrence. Cerebrospinal fluid (CSF) is a source of brain tumor biomarkers. We analyzed the proteome of waste CSF from extraventricular drainage (EVD) from 29 children bearing different brain tumors and 17 controls needing EVD insertion for unrelated causes. 1598 and 1526 proteins were identified by liquid chromatography-coupled tandem mass spectrometry proteomics in CSF control and brain tumor patients, respectively, 263 and 191 proteins being exclusive of either condition. Bioinformatic analysis revealed promising protein biomarkers for the discrimination between control and tumor (TATA-binding protein-associated factor 15 and S100 protein B). Moreover, Thymosin beta-4 (TMSB4X) and CD109, and 14.3.3 and HSP90 alpha could discriminate among other brain tumors and low-grade gliomas plus glyoneuronal tumors/pilocytic astrocytoma, or embryonal tumors/medulloblastoma. Biomarkers were validated by ELISA assay. Our method was able to distinguish among brain tumor vs non-tumor/hemorrhagic conditions (controls) and to differentiate two large classes of brain tumors. Further prospective studies may assess whether the biomarkers proposed by our discovery approach can be identified in other bodily fluids, therefore less invasively, and are useful to guide therapy and predict recurrences.

The potential therapeutic effects of curcumin on pregnancy complications: Novel insights into reproductive medicine

Pregnancy complications including preeclampsia, preterm birth, intrauterine growth restriction, and gestational diabetes are the main adverse reproductive outcomes. Excessive inflammation and oxidative stress play crucial roles in the pathogenesis of pregnancy disorders. Curcumin, the main polyphenolic compound derived from Curcuma longa, is mainly known by its anti-inflammatory and antioxidant properties. There are in vitro and in vivo reports revealing the preventive and ameliorating effects of curcumin against pregnancy complications. Here, we aimed to seek mechanisms underlying the modulatory effects of curcumin on dysregulated inflammatory and oxidative responses in various pregnancy complications.

Window of opportunity for human amnion epithelial stem cells to attenuate astrogliosis after umbilical cord occlusion in preterm fetal sheep

There is increasing evidence that administration of many types of stem cells, including human amnion epithelial cells (hAECs), can reduce hypoxic-ischemic injury, including in the perinatal brain. However, the therapeutic window for single dose treatment is not known. We compared the effects of early and delayed intracerebroventricular administration of hAECs in fetal sheep at 0.7 gestation on brain injury induced by 25 minutes of complete umbilical cord occlusion (UCO) or sham occlusion. Fetuses received either 1 × 10⁶ hAECs or vehicle alone, as an infusion over 1 hour, either 2 or 24 hours after UCO. Fetuses were killed for brain histology at 7 days post-UCO. hAEC infusion at both 2 and 24 hours had dramatic anti-inflammatory and anti-gliotic effects, including significantly attenuating the increase in microglia after UCO in the white and gray matter and the number of astrocytes in the white matter. Both protocols partially improved myelination, but had no effect on total or immature/mature numbers of oligodendrocytes. Neuronal survival in the hippocampus was increased by hAEC infusion at either 2 or 24 hours, whereas only hAECs at 24 hours were associated with improved neuronal survival in the striatum and thalamus. Neither protocol improved recovery of electroencephalographic (EEG) power. These data suggest that a single infusion of hAECs is anti-inflammatory, anti-gliotic, and neuroprotective in preterm fetal sheep when given up to 24 hours after hypoxia-ischemia, but was associated with limited white matter protection after 7 days recovery and no improvement in the recovery of EEG power.

Cerebral Oxygenation in Preterm Infants With Necrotizing Enterocolitis

BACKGROUND AND OBJECTIVES

Preterm infants with necrotizing enterocolitis (NEC) are known to have worse neurodevelopmental outcomes, but there is no substantial evidence to support an underlying pathophysiology. We aimed to examine whether cerebral oxygenation differs in those infants who develop NEC compared to cerebral oxygenation in those who do not.

METHODS

We examined 48 infants <30 weeks' gestation admitted to a tertiary level NICU from October 2016 to May 2018. Infants with birth weight less than or equal to the second percentile, abnormal antenatal dopplers or twin-to-twin-transfusion-syndrome were excluded. Cerebral oximetry measurements were performed by using a near-infrared spectroscopy (NIRS) monitor weekly for 60 minutes, allowing measurement of cerebral tissue oxygenation index from the first week of life to 36 weeks postconceptional age. Weekly clinical status was also recorded. NEC was defined as greater than or equal to Bell stage 2.

RESULTS

The median birth weight was 884 g (range of 460-1600 g), the median weeks' gestational age was 26 + 3/7 (23 + 0/7 to 29 + 6/7), and 52% were girls. In total, 276 NIRS measurements were completed, and 7 infants developed NEC. NIRS measurements from 1 infant with NEC and 4 infants without NEC who developed hemorrhagic parenchymal infarcts were excluded from analysis. Infants who developed NEC had significantly lower cerebral tissue oxygenation index than those who did not (P = .011), even when adjusted for confounders, including gestational age, birth weight, patent ductus arteriosus, enteral feeds, sex, ethnicity, and hemoglobin.

CONCLUSIONS

Infants with NEC have significantly lower cerebral tissue oxygenation throughout their neonatal intensive care stay in comparison with those who did not develop NEC. This is a novel finding and could explain their worse neurodevelopmental outcome.

[Hypoxic-ischemic brain damage in premature newborns]

One of the main causes of cerebral dysfunction in premature newborns is hypoxia. High mortality and lifelong morbidity in these children is a frequent result of neonatal hypoxic brain damage. The article presents some data on the prevalence of neurological diseases that have arisen in the perinatal period, and highlights the key etiological factors leading to hypoxia in both the intranatal and early postnatal periods. The pathogenesis of hypoxic-ischemic brain lesions in premature infants is described in detail. At the same time, more careful consideration is given to the glutathione system, which protects against lipid peroxidation, the glutamate-calcium cascade, and the excitotoxicity mediated by it, as well as the processes of necrosis and apoptosis of nerve cells. The advantages and disadvantages of modern methods for diagnosing cerebral lesions are noted, and the principles of treatment of these disorders are analyzed.

Neonatal Encephalopathy Is Associated With Altered IL-8 and GM-CSF Which Correlates With Outcomes

Aim: To investigate the relationship between cytokines associated with innate immune cell activation and brain injury and outcome in infants with NE compared to neonatal controls. Methods: Serum and CSF biomarkers associated with activated neutrophils and monocytes [Interleukin-8 (IL-8) and Granulocyte-Macrophage-Colony-Stimulating-Factor (GM-CSF)] were serially measured using duplex immunoassays on days 1, 3 and 7 in term newborns with NE and controls. Results were compared to grade of encephalopathy, seizures, MRI brain imaging, mortality and Bayley Score of Infant and Toddler Development (Bayley-III) at 2 years of age. Results: Ninety-four infants had serum samples collected with 34 CSF samples. NE Grade II/III was significantly associated with elevated on day 2 serum IL-8. Mortality was best predicted by elevated day 1 IL-8. GM-CSF was initially elevated on day 1 and abnormal MRI imaging was associated with decreased day 2 GM-CSF. Elevated GM-CSF at day of life 6-7 correlated negatively with composite cognitive, language and motor Bayley-III scores at 2 years. Conclusion: Moderate or severe NE and mortality was associated with elevated IL-8. Day 2 GM-CSF could predict abnormal MRI results in NE and Bayley-III. Therefore, these cytokines are altered in NE and may predict early outcomes and further implicate inflammatory processes in NE.

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.

Increased Peripheral Interleukin 10 Relate to White Matter Integrity in Schizophrenia

Background: Schizophrenia is characterized by the disruption of microstructural white matter (WM) integrity, while the pathogenesis remains unclear. Inflammation has been associated with the WM pathology in schizophrenia. Interleukin 10 (IL-10) has been proven to be related to schizophrenia in both animal and human models. The aim of this study was to explore whether peripheral IL-10 was associated with microstructural WM integrity in schizophrenia.

Methods: A total of 47 patients with schizophrenia (SZ) and 49 healthy controls (HC) underwent diffusion tensor imaging and venous blood sampling. Tract-based spatial statistics was conducted to explore the differences in fractional anisotropy (FA), radial diffusivity (RD), mean diffusivity (MD), and axial diffusivity (AD) between patients and controls. A quantitative chemiluminescence assay was performed to measure peripheral IL-10 levels. General linear regression analysis using a stepwise method was applied to examine the relationship between peripheral IL-10 and diffusion measures.

Results: Compared with the HC, peripheral IL-10 levels were higher and a significant reduction of FA and AD, and increase of RD and MD were observed in SZ (corrected p < 0.05). A regression analysis revealed that peripheral IL-10 was negatively correlated with FA in the right posterior thalamic radiation and left inferior fronto-occipital fasciculus, in SZ (β = -0.51, p = 0.01; β = -0.47, p = 0.02, respectively) but not in HC (β = -0.01, p = 0.95; β = -0.003, p = 0.98, respectively), and the differences in regression curves were significant (z = 2.50, p = 0.01; z = 2.37, p = 0.02, respectively). IL-10 was negatively connected with MD in the right parietal arcuate fasciculus (β = -0.40, p = 0.048) and body of the corpus callosum (β = -0.43, p = 0.03) in SZ, while not in HC. The magnitude of correlation in the patient and control group was different (z = 2.48, p = 0.01 and z = 2.61, p < 0.01, respectively). In addition, IL-10 was positively correlated with RD in the right parietal arcuate fasciculus in patients (β = 0.45, p = 0.04) but not in HC (β = 0.26, p = 0.94), but the correlation coefficients were not significant (z = 0.98, p = 0.32).

Conclusion: Our findings demonstrated that elevated peripheral IL-10 levels were associated with the disruption of microstructural WM integrity in schizophrenia, supporting the notion that inflammation plays a regulatory role in the pathology of microstructural WM and is associated with schizophrenia.

Body composition and cognition in preschool-age children with congenital gastrointestinal anomalies

BACKGROUND

Children with congenital gastrointestinal anomalies (CGIAs) experience multiple stressors while hospitalized in neonatal intensive care units during an essential time of growth and development. Early stress and inadequate nutrition are linked to altered growth patterns and later neurodevelopmental delays. In other at-risk populations, improved fat-free mass (FFM) accretion is associated with improved cognitive outcomes.

OBJECTIVE

To determine if body composition is associated with cognitive function in preschool-age children with CGIAs.

STUDY DESIGN

An observational study examined body composition and cognition in 34 preschool-age children with CGIAs. Anthropometric measurements and body composition testing via air displacement plethysmography were obtained. Measurements were compared with a reference group of healthy, term-born children. Cognition was measured with the NIH Toolbox Early Childhood Cognition Battery. Linear regression was used to test the association of body composition with cognitive function.

RESULTS

Compared with the reference group, children with CGIAs had similar anthropometric measurements (weight, height, and body mass index z-scores) and body composition at preschool-age. Processing speed scores were lower than standardized means (p = 0.001). Increased FFM was associated with higher receptive vocabulary scores (p = 0.001), cognitive flexibility scores (p = 0.005), and general cognitive function scores (p = 0.05).

CONCLUSIONS

At preschool-age, children with CGIAs have similar growth and body composition to their peers. In children with CGIAs, higher FFM was associated with higher cognitive scores. Closer tracking of body composition and interventions aimed at increasing FFM may improve long-term outcomes in this population.

Delayed intranasal infusion of human amnion epithelial cells improves white matter maturation after asphyxia in preterm fetal sheep

Perinatal hypoxic-ischemic (HI) brain injury remains highly associated with neurodevelopmental disability after preterm birth. There is increasing evidence that disability is linked with impaired white matter maturation, but there is no specific treatment. In this study, we evaluated whether, in preterm fetal sheep, delayed intranasal infusion of human amnion epithelial cells (hAECs) given 1, 3 and 10 days after severe HI, induced by umbilical cord occlusion for 25 min, can restore white matter maturation or reduce delayed cell loss. After 21 days recovery, asphyxia was associated with reduced electroencephalographic (EEG) maturation, brain weight and cortical area, impaired maturation of oligodendrocytes (OLs), no significant loss of total OLs but a marked reduction in immature/mature OLs and reduced myelination. Intranasal infusion of hAECs was associated with improved brain weight and restoration of immature/mature OLs and fractional area of myelin basic protein, with reduced microglia and astrogliosis. Cortical EEG frequency distribution was partially improved, with reduced loss of cortical area, and attenuated cleaved-caspase-3 expression and microgliosis. Neuronal survival in deep grey matter nuclei was improved, with reduced microglia, astrogliosis and cleaved-caspase-3-positive apoptosis. These findings suggest that delayed intranasal hAEC administration has potential to alleviate chronic dysmaturation after perinatal HI.

Preterm brain Injury: White matter injury

Despite the advances in neonatal intensive care, the preterm brain remains vulnerable to white matter injury (WMI) and disruption of normal brain development (i.e., dysmaturation). Compared to severe cystic WMI encountered in the past decades, contemporary cohorts of preterm neonates experience milder WMIs. More than destructive lesions, disruption of the normal developmental trajectory of cellular elements of the white and the gray matter occurs. In the acute phase, in response to hypoxia-ischemia and/or infection and inflammation, multifocal areas of necrosis within the periventricular white matter involve all cellular elements. Later, chronic WMI is characterized by diffuse WMI with aberrant regeneration of oligodendrocytes, which fail to mature to myelinating oligodendrocytes, leading to myelination disturbances. Complete neuronal degeneration classically accompanies necrotic white matter lesions, while altered neurogenesis, represented by a reduction of the dendritic arbor and synapse formation, is observed in response to diffuse WMI. Neuroimaging studies now provide more insight in assessing both injury and dysmaturation of both gray and white matter. Preterm brain injury remains an important cause of neurodevelopmental disabilities, which are still observed in up to 50% of the preterm survivors and take the form of a complex combination of motor, cognitive, and behavioral concerns.

Role of Prenatal Hypoxia in Brain Development, Cognitive Functions, and Neurodegeneration

This review focuses on the role of prenatal hypoxia in the development of brain functions in the postnatal period and subsequent increased risk of neurodegenerative disorders in later life. Accumulating evidence suggests that prenatal hypoxia in critical periods of brain formation results in significant changes in development of cognitive functions at various stages of postnatal life which correlate with morphological changes in brain structures involved in learning and memory. Prenatal hypoxia also leads to a decrease in brain adaptive potential and plasticity due to the disturbance in the process of formation of new contacts between cells and propagation of neuronal stimuli, especially in the cortex and hippocampus. On the other hand, prenatal hypoxia has a significant impact on expression and processing of a variety of genes involved in normal brain function and their epigenetic regulation. This results in changes in the patterns of mRNA and protein expression and their post-translational modifications, including protein misfolding and clearance. Among proteins affected by prenatal hypoxia are a key enzyme of the cholinergic system-acetylcholinesterase, and the amyloid precursor protein (APP), both of which have important roles in brain function. Disruption of their expression and metabolism caused by prenatal hypoxia can also result, apart from early cognitive dysfunctions, in development of neurodegeneration in later life. Another group of enzymes affected by prenatal hypoxia are peptidases involved in catabolism of neuropeptides, including amyloid-β peptide (Aβ). The decrease in the activity of neprilysin and other amyloid-degrading enzymes observed after prenatal hypoxia could result over the years in an Aβ clearance deficit and accumulation of its toxic species which cause neuronal cell death and development of neurodegeneration. Applying various approaches to restore expression of neuronal genes disrupted by prenatal hypoxia during postnatal development opens an avenue for therapeutic compensation of cognitive dysfunctions and prevention of Aβ accumulation in the aging brain and the model of prenatal hypoxia in rodents can be used as a reliable tool for assessment of their efficacy.

The Cerebrospinal Fluid Inflammatory Response to Preterm Birth

Background: Preterm birth is the leading risk factor for perinatal white matter injury, which can lead to motor and neuropsychiatric impairment across the life course. There is an unmet clinical need for therapeutics. White matter injury is associated with an altered inflammatory response in the brain, primarily led by microglia, and subsequent hypomyelination. However, microglia can release both damaging and trophic factors in response to injury, and a comprehensive assessment of these factors in the preterm central nervous system (CNS) has not been carried out.

Method: A custom antibody array was used to assess relative levels of 50 inflammation- and myelination-associated proteins in the cerebrospinal fluid (CSF) of preterm infants in comparison to term controls.

Results: Fifteen proteins differed between the groups: BDNF, BTC, C5a, FasL, Follistatin, IL-1β, IL-2, IL-4, IL-9, IL-17A, MIP-1α, MMP8, SPP1, TGFβ, and TNFβ (p < 0.05). To investigate the temporal regulation of these proteins after injury, we mined a gene expression dataset of microglia isolated from a mouse model of developmental white matter injury. Microglia in the experimental model showed dynamic temporal expression of genes encoding these proteins, with an initial and sustained pro-inflammatory response followed by a delayed anti-inflammatory response, and a continuous expression of genes predicted to inhibit healthy myelination.

Conclusion: Preterm CSF shows a distinct neuroinflammatory profile compared to term controls, suggestive of a complex neural environment with concurrent damaging and reparative signals. We propose that limitation of pro-inflammatory responses, which occur early after perinatal insult, may prevent expression of myelination-suppressive genes and support healthy white matter development.

Necrotizing enterocolitis is associated with acute brain responses in preterm pigs

Background

Necrotizing enterocolitis (NEC) is an acute gut inflammatory disorder that occurs in preterm infants in the first weeks after birth. Infants surviving NEC often show impaired neurodevelopment. The mechanisms linking NEC lesions with later neurodevelopment are poorly understood but may include proinflammatory signaling in the immature brain. Using preterm pigs as a model for preterm infants, we hypothesized that severe intestinal NEC lesions are associated with acute effects on the developing hippocampus.

Methods

Cesarean-delivered preterm pigs (n = 117) were reared for 8 days and spontaneously developed variable severity of NEC lesions. Neonatal arousal, physical activity, and in vitro neuritogenic effects of cerebrospinal fluid (CSF) were investigated in pigs showing NEC lesions in the colon (Co-NEC) or in the small intestine (Si-NEC). Hippocampal transcriptome analysis and qPCR were used to assess gene expressions and their relation to biological processes, including neuroinflammation, and neural plasticity. Microglia activation was quantified by stereology. The neuritogenic response to selected proteins was investigated in primary cultures of hippocampal neurons.

Results

NEC development rapidly reduced the physical activity of pigs, especially when lesions occurred in the small intestine. Si-NEC and Co-NEC were associated with 27 and 12 hippocampal differentially expressed genes (DEGs), respectively. These included genes related to neuroinflammation (i.e., S100A8, S100A9, IL8, IL6, MMP8, SAA, TAGLN2) and hypoxia (i.e., PDK4, IER3, TXNIP, AGER), and they were all upregulated in Si-NEC pigs. Genes related to protection against oxidative stress (HBB, ALAS2) and oligodendrocytes (OPALIN) were downregulated in Si-NEC pigs. CSF collected from NEC pigs promoted neurite outgrowth in vitro, and the S100A9 and S100A8/S100A9 proteins may mediate the neuritogenic effects of NEC-related CSF on hippocampal neurons. NEC lesions did not affect total microglial cell number but markedly increased the proportion of Iba1-positive amoeboid microglial cells.

Conclusions

NEC lesions, especially when present in the small intestine, are associated with changes to hippocampal gene expression that potentially mediate neuroinflammation and disturbed neural circuit formation via enhanced neuronal differentiation. Early brain-protective interventions may be critical for preterm infants affected by intestinal NEC lesions to reduce their later neurological dysfunctions.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1201-x) contains supplementary material, which is available to authorized users.

A review of the conundrum of mild hypoxic-ischemic encephalopathy: Current challenges and moving forward

A review of the conundrum called mild hypoxic-ischemic encephalopathy (HIE) is provided. During the past decades, the definition of HIE has evolved to accommodate the short window of time required for the initiation of therapeutic hypothermia. Also, neurological evaluations have changed with the use of simpler staging systems that can be applied within the first 6 h of life. In this review, we discuss the challenges in the identification of newborns with "mild HIE" within 6 h after birth, the limitations in the existing early biomarkers of brain injury, and the current knowledge gaps in the long term neurodevelopmental outcomes of infants diagnosed with mild HIE. Progress in the understanding of mild HIE and its sequelae continues to be hindered by the lack of a standardized definition for mild HIE that will reliably identify at-risk infants who may benefit from neuroprotective strategies.

Multiple Postnatal Infections in Newborns Born Preterm Predict Delayed Maturation of Motor Pathways at Term-Equivalent Age with Poorer Motor Outcomes at 3 Years

OBJECTIVES

To evaluate whether the number of postnatal infections is associated with abnormal white matter maturation and poorer motor neurodevelopmental outcomes at 36 months of corrected age.

STUDY DESIGN

A prospective longitudinal cohort study was undertaken of 219 newborns born preterm at 24-32 weeks of gestational age recruited between 2006 and 2013 with magnetic resonance imaging of the brain both early in life and at term-equivalent age. Postnatal infection was defined as any clinical infection or positive culture ≥72 hours after birth. White matter maturation was assessed by magnetic resonance spectroscopic imaging, magnetic resonance diffusion tensor imaging, and tract-based spatial statistics. Neurodevelopmental outcomes were assessed in 175 (82% of survivors) infants with Bayley Scales of Infant and Toddler Development-III composite scores and Peabody Developmental Motor Scales at 35 months of corrected age (IQR 34-37 months). Infection groups were compared via the Fisher exact test, Kruskal-Wallis test, and generalized estimating equations.

RESULTS

Of 219 neonates born preterm (median gestational age 27.9 weeks), 109 (50%) had no postnatal infection, 83 (38%) had 1 or 2 infections, and 27 (12%) had ≥3 infections. Infants with postnatal infections had more cerebellar hemorrhage. Infants with ≥3 infections had lower N-acetylaspartate/choline in the white matter and basal ganglia regions, lower fractional anisotropy in the posterior limb of the internal capsule, and poorer maturation of the corpus callosum, optic radiations, and posterior limb of the internal capsule on tract-based spatial statistics analysis as well as poorer Bayley Scales of Infant and Toddler Development-III (P = .02) and Peabody Developmental Motor Scales, Second Edition, motor scores (P < .01).

CONCLUSIONS

In newborns born preterm, ≥3 postnatal infections predict impaired development of the motor pathways and poorer motor outcomes in early childhood.

TRPM2 Channel Aggravates CNS Inflammation and Cognitive Impairment via Activation of Microglia in Chronic Cerebral Hypoperfusion

Chronic cerebral hypoperfusion is a characteristic seen in widespread CNS diseases, including neurodegenerative and mental disorders, and is commonly accompanied by cognitive impairment. Recently, several studies demonstrated that chronic cerebral hypoperfusion can induce the excessive inflammatory responses that precede neuronal dysfunction; however, the precise mechanism of cognitive impairment due to chronic cerebral hypoperfusion remains unknown. Transient receptor potential melastatin 2 (TRPM2) is a Ca²⁺-permeable channel that is abundantly expressed in immune cells and is involved in aggravation of inflammatory responses. Therefore, we investigated the pathophysiological role of TRPM2 in a mouse chronic cerebral hypoperfusion model with bilateral common carotid artery stenosis (BCAS). When male mice were subjected to BCAS, cognitive dysfunction and white matter injury at day 28 were significantly improved in TRPM2 knock-out (TRPM2-KO) mice compared with wild-type (WT) mice, whereas hippocampal damage was not observed. There were no differences in blood-brain barrier breakdown and H₂O₂ production between the two genotypes at 14 and 28 d after BCAS. Cytokine production was significantly suppressed in BCAS-operated TRPM2-KO mice compared with WT mice at day 28. In addition, the number of Iba1-positive cells gradually decreased from day 14. Moreover, daily treatment with minocycline significantly improved cognitive perturbation. Surgical techniques using bone marrow chimeric mice revealed that activated Iba1-positive cells in white matter could be brain-resident microglia, not peripheral macrophages. Together, these findings suggest that microglia contribute to the aggravation of cognitive impairment by chronic cerebral hypoperfusion, and that TRPM2 may be a potential target for chronic cerebral hypoperfusion-related disorders.SIGNIFICANCE STATEMENT Chronic cerebral hypoperfusion is manifested in a wide variety of CNS diseases, including neurodegenerative and mental disorders that are accompanied by cognitive impairment; however, the underlying mechanisms require clarification. Here, we used a chronic cerebral hypoperfusion mouse model to investigate whether TRPM2, a Ca²⁺-permeable cation channel highly expressed in immune cells, plays a destructive role in the development of chronic cerebral hypoperfusion-induced cognitive impairment, and propose a new hypothesis in which TRPM2-mediated activation of microglia, not macrophages, specifically contributes to the pathology through the aggravation of inflammatory responses. These findings shed light on the understanding of the mechanisms of chronic cerebral hypoperfusion-related inflammation, and are expected to provide a novel therapeutic molecule for cognitive impairment in CNS diseases.

A comparison of blood and cerebrospinal fluid cytokines (IL-1β, IL-6, IL-18, TNF-α) in neonates with perinatal hypoxia

Perinatal hypoxia-ischemia is a specific and important pathological event in neonatal care practice. The data on relationship between the concentrations of cytokines in blood and cerebrospinal fluid (CSF) and perinatal brain injury are scarce. The aim of this study is to evaluate changes in interleukin (IL-1β, IL-6, and IL-18) and tumor necrosis factor alpha (TNF-α) levels in newborns with perinatal hypoxia (PNH). CSF and serum samples of 35 term and near-term (35-40 weeks) newborns with PNH, at the age of 3-96 hours, were analyzed using enzyme-linked immunosorbent assay. Control group consisted of 25 non-asphyxic/non-hypoxic infants of the same age sampled for clinically suspected perinatal meningitis, but proven negative and healthy otherwise. The cytokine values in CSF and serum samples were determined in relation to initial hypoxic-ischemic encephalopathy (HIE) staged according the Sarnat/Sarnat method, and compared with neurological outcome at 12 months of age estimated using Amiel-Tison procedure. The concentrations of IL-6 and TNF-α in serum of PNH patients were significantly higher compared to control group (p = 0.0407 and p = 0.023, respectively). No significant difference between average values of cytokines in relation to the stage of HIE was observed. Significantly higher levels of IL-6 and IL-18 corresponded to a mildly abnormal neurological outcome, while higher levels of IL-6 and TNF-α corresponded to a severely abnormal neurological outcome, at 12 months of age. Elevated serum levels of IL-6 and TNF-α better corresponded with hypoxia/ischemia compared to CSF values, within 96 hours of birth. Also, higher serum levels of IL-6, TNF-α, and IL-18 corresponded better with abnormal neurological outcome at 12 months of age, compared to CSF values.

In Premature Newborns Intraventricular Hemorrhage Causes Cerebral Vasospasm and Associated Neurodisability via Heme-Induced Inflammasome-Mediated Interleukin-1 Production and Nitric Oxide Depletion

BACKGROUND

Intraventricular hemorrhage (IVH) occurs in 60-70% of neonates weighing 500-750 g and 10-20% of those weighing 1,000-1,500 g. All forms of IVH have been associated with neurocognitive deficits. Both subarachnoid and IVHs have been associated with delayed vasospasm leading to neurological deficits. Pathways linking hemoglobin release from blood clots to vasospasm include heme-induced activation of inflammasomes releasing interleukin-1 (IL-1) that can cause calcium dependent and independent vasospasm. Free hemoglobin is a potent scavenger of nitric oxide (NO). Depletion of NO, a potent endogenous vasodilator, has been associated with features of vasospasm.

HYPOTHESIS

In premature newborns, IVH causes cerebral vasospasm and associated neurodisability via heme-induced increased inflammasome-mediated IL-1 production and NO depletion.

CONFIRMATION OF HYPOTHESIS AND IMPLICATIONS

This hypothesis could be confirmed in the IVH animal model with visualization of any associated vasospasm by angiography and in newborns with IVH by transcranial Doppler ultrasonography and correlation with cerebrospinal fluid IL-1 and NO metabolite levels. Confirmation of the role of heme in activation of inflammasomes causing IL-1 production and NO binding could be achieved by measuring the effect of heme scavenging interventions on IL-1 levels and levels of NO metabolites. In addition to removal of the accumulated blood of an IVH by drainage, irrigation, and fibrinolytic therapy intrathecal application of vasodilators and heme scavenging agents like haptoglobin and haemopexin and systemic treatment with inhibitors of inflammasomes like telmisartan could be used to prevent and treat cerebral vasospasm, and thus reduce the risk of associated brain injury in premature neonates.

Neurological consequences of systemic inflammation in the premature neonate

Despite substantial progress in neonatal care over the past two decades leading to improved survival of extremely premature infants, extreme prematurity continues to be associated with long term neurodevelopmental impairments. Cerebral white matter injury is the predominant form of insult in preterm brain leading to adverse neurological consequences. Such brain injury pattern and unfavorable neurologic sequelae is commonly encountered in premature infants exposed to systemic inflammatory states such as clinical or culture proven sepsis with or without evidence of meningitis, prolonged mechanical ventilation, bronchopulmonary dysplasia, necrotizing enterocolitis and chorioamnionitis. Underlying mechanisms may include cytokine mediated processes without direct entry of pathogens into the brain, developmental differences in immune response and complex neurovascular barrier system that play a critical role in regulating the cerebral response to various systemic inflammatory insults in premature infants. Understanding of these pathologic mechanisms and clinical correlates of such injury based on serum biomarkers or brain imaging findings on magnetic resonance imaging will pave way for future research and translational therapeutic opportunities for the developing brain.

Complement C5a is present in CSF of human newborns and is elevated in association with preterm birth

Neuroinflammation contributes to developmental brain injury associated with preterm birth, but the mediators that drive it are incompletely understood. Previous studies have shown that complement C5a is present and injurious in the brains of foetal mice exposed to preterm labour. Here, we demonstrate that C5a is present in the cerebrospinal fluid of newborn human infants and that levels are elevated in those born preterm. The difference is not explained by systemic infection. Complement activation in the neonatal brain and its role as a potential therapeutic target in preterm brain injury warrant further study. Activation in the neonatal brain and its role as a potential therapeutic target for preterm brain injury warrants further study.

Intra-amniotic LPS causes acute neuroinflammation in preterm rhesus macaques

Background

Chorioamnionitis is associated with an increased risk of brain injury in preterm neonates. Inflammatory changes in brain could underlie this injury. Here, we evaluated whether neuroinflammation is induced by chorioamnionitis in a clinically relevant model.

Methods

Rhesus macaque fetuses were exposed to either intra-amniotic (IA) saline, or IA lipopolysaccharide (LPS) (1 mg) 16 or 48 h prior to delivery at 130 days (85 % of gestation) (n = 4–5 animals/group). We measured cytokines in the cerebrospinal fluid (CSF), froze samples from the left brain for molecular analysis, and immersion fixed the right brain hemisphere for immunohistology. We analyzed the messenger RNA (mRNA) levels of the pro-inflammatory cytokines IL-1β, CCL2, TNF-α, IL-6, IL-8, IL-10, and COX-2 in the periventricular white matter (PVWM), cortex, thalamus, hippocampus, and cerebellum by RT-qPCR. Brain injury was assessed by immunohistology for myelin basic protein (MBP), IBA1 (microglial marker), GFAP (astrocyte marker), OLIG2 (oligodendrocyte marker), NeuN (neuronal marker), CD3 (T cells), and CD14 (monocytes). Microglial proliferation was assessed by co-immunostaining for IBA1 and Ki67. Data were analyzed by ANOVA with Tukey’s post-test.

Results

IA LPS increased mRNA expression of pro-inflammatory cytokines in the PVWM, thalamus, and cerebellum, increased IL-6 concentration in the CSF, and increased apoptosis in the periventricular area after 16 h. Microglial proliferation in the white matter was increased 48 h after IA LPS.

Conclusions

LPS-induced chorioamnionitis caused neuroinflammation, microglial proliferation, and periventricular apoptosis in a clinically relevant model of chorioamnionitis in fetal rhesus macaques. These findings identify specific responses in the fetal brain and support the hypothesis that neuroinflammatory changes may mediate the adverse neurodevelopmental outcomes associated with chorioamnionitis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0706-4) contains supplementary material, which is available to authorized users.

Inflammatory Biomarkers of Birth Asphyxia

Although therapies in addition to whole-body cooling are being developed to treat the neonate at risk for hypoxic-ischemic encephalopathy, we have no quickly measured serum inflammatory or neuronal biomarkers to acutely and accurately identify brain injury or to follow the efficacy of therapy. This review covers inflammatory serum biomarkers in the setting of birth asphyxia that can help assess the degree or severity of encephalopathy at birth and neurodevelopmental outcomes. These biomarkers still need to be independently validated in large cohorts before they are ready for clinical implementation in practice.

The Developing Microbiome of the Preterm Infant

PURPOSE

To determine the importance of the neonatal microbiome in intestinal and overall health.

METHOD

A review of existing literature.

FINDINGS AND IMPLICATIONS

The microbiome is increasingly understood to have a significant role in health and disease. However, the microbiome of the preterm infant is unique, with simple microbial communities exposed to a consistent diet in a regulated environment, and development from naive to stable under the influence of the neonatal intensive care unit. This early microbiome encounters a still developing host and thus has the potential to program fundamental pathways with implications for neonatal and later outcomes.

Circulating tumour necrosis factor is highly correlated with brainstem serotonin transporter availability in humans

Preclinical studies demonstrate that pro-inflammatory cytokines increase serotonin transporter availability and function, leading to depressive symptoms in rodent models. Herein we investigate associations between circulating inflammatory markers and brainstem serotonin transporter (5-HTT) availability in humans. We hypothesised that higher circulating inflammatory cytokine concentrations, particularly of tumour necrosis factor (TNF-α), would be associated with greater 5-HTT availability, and that TNF-α inhibition with etanercept (sTNFR:Fc) would in turn reduce 5-HTT availability. In 13 neurologically healthy adult women, plasma TNF-α correlated significantly with 5-HTT availability (rho=0.6; p=0.03) determined by [(123)I]-beta-CIT SPECT scanning. This association was replicated in an independent sample of 12 patients with psoriasis/psoriatic arthritis (rho=0.76; p=0.003). Indirect effects analysis, showed that there was a significant overlap in the variance explained by 5-HTT availability and TNF-α concentrations on BDI scores. Treatment with etanercept for 6-8weeks was associated with a significant reduction in 5-HTT availability (Z=2.09; p=0.03; r=0.6) consistent with a functional link. Our findings confirm an association between TNF-α and 5-HTT in both the basal physiological and pathological condition. Modulation of both TNF-α and 5-HTT by etanercept indicate the presence of a mechanistic pathway whereby circulating inflammatory cytokines are related to central nervous system substrates underlying major depression.

Elevated plasma and cerebrospinal fluid interleukin-1 beta and tumor necrosis factor-alpha concentration and combined outcome of death or abnormal neuroimaging in preterm neonates with early-onset clinical sepsis

OBJECTIVE

Prematurity and sepsis are the major contributors of neonatal mortality and neurodevelopmental sequelae. The present study was conducted to measure the plasma and cerebrospinal fluid (CSF) concentration of interleukin (IL)-1β and tumor necrotic factor (TNF)-α in preterm neonates with early-onset clinical sepsis (EOCS), and to find out their association with combined outcome of death or abnormal neuroimaging.

STUDY DESIGN

Thirty-two preterm (⩽34 weeks) neonates with EOCS and 32 gestational age-matched, healthy neonates served as cases and controls, respectively. Samples were collected soon after birth. Neonates were followed up clinically and by serial cranial ultrasonography (CUS) until discharge and subsequently by magnetic resonance imaging (MRI) of brain until 1 year. Developmental screening was done by Denver Developmental Screening test-II.

RESULT

In EOCS group, no neonate had any clinical/microbiological evidence of meningitis. Blood culture was positive in 17 (53%). CUS was abnormal in 12 (37%) (intracranial hemorrhage-11, periventricular leukomalacia-1). Ten (31%) neonates expired. Significant elevation of plasma and CSF IL-1β and TNF-α was observed in the EOCS group. On follow-up, seven (22%) neonates showed evidence of white matter damage in MRI, two of them had developmental delay and microcephaly. Plasma and CSF IL-1β and TNF-α concentration were significantly elevated in deceased neonates and those with abnormal neuroimaging. Both biomarkers demonstrated high predictive accuracy for poor outcome in receiver-operating curve analysis.

CONCLUSION

Elevation of plasma and CSF IL-1β and TNF-α is associated with an increase in the combined outcome of death or abnormal neuroimaging in preterm neonates with EOCS in the absence of clinical/microbiological evidence of meningitis with high predictive accuracy.

New means to assess neonatal inflammatory brain injury

Preterm infants are especially vulnerable to infection-induced white matter injury, associated with cerebral palsy, cognitive and psychomotor impairment, and other adverse neurological outcomes. The etiology of such lesions is complex and multifactorial. Furthermore, timing and length of exposure to infection also influence neurodevelopmental outcomes. Different mechanisms have been posited to mediate the observed brain injury including microglial activation followed by subsequent release of pro-inflammatory species, glutamate-induced excitotoxicity, and vulnerability of developing oligodendrocytes to cerebral insults. The prevalence of such neurological impairments requires an urgent need for early detection and effective neuroprotective strategies. Accordingly, noninvasive methods of monitoring disease progression and therapy effectiveness are essential. While diagnostic tools using biomarkers from bodily fluids may provide useful information regarding potential risks of developing neurological diseases, the use of magnetic resonance imaging/spectroscopy has emerged as a promising candidate for such purpose. Various pharmacological agents have demonstrated protective effects in the immature brain in animal models; however, few studies have progressed to clinical trials with promising results.

Anti-IL-6 neutralizing antibody modulates blood-brain barrier function in the ovine fetus

Impaired blood-brain barrier function represents an important component of hypoxic-ischemic brain injury in the perinatal period. Proinflammatory cytokines could contribute to ischemia-related blood-brain barrier dysfunction. IL-6 increases vascular endothelial cell monolayer permeability in vitro. However, contributions of IL-6 to blood-brain barrier abnormalities have not been examined in the immature brain in vivo. We generated pharmacologic quantities of ovine-specific neutralizing anti-IL-6 mAbs and systemically infused mAbs into fetal sheep at 126 days of gestation after exposure to brain ischemia. Anti-IL-6 mAbs were measured by ELISA in fetal plasma, cerebral cortex, and cerebrospinal fluid, blood-brain barrier permeability was quantified using the blood-to-brain transfer constant in brain regions, and IL-6, tight junction proteins, and plasmalemma vesicle protein (PLVAP) were detected by Western immunoblot. Anti-IL-6 mAb infusions resulted in increases in mAb (P < 0.05) in plasma, brain parenchyma, and cerebrospinal fluid and decreases in brain IL-6 protein. Twenty-four hours after ischemia, anti-IL-6 mAb infusions attenuated ischemia-related increases in blood-brain barrier permeability and modulated tight junction and PLVAP protein expression in fetal brain. We conclude that inhibiting the effects of IL-6 protein with systemic infusions of neutralizing antibodies attenuates ischemia-related increases in blood-brain barrier permeability by inhibiting IL-6 and modulates tight junction proteins after ischemia.

Serum biomarkers to evaluate the integrity of the neurovascular unit

Biomarkers have the potential to enable the clinicians to screen infants for brain injury, monitor progression of disease, identify injured brain regions, assess efficacy of neuroprotective therapies, and offer hope to identify the timing of the injury, thus shedding light on the potential pathophysiology and the most effective therapy. Currently, clinicians do not routinely use biomarkers to care for neonates with Neonatal Encephalopathy (NE) and brain injury due to prenatal hypoxia-asphyxia. This review will cover potential biomarkers of the neurovascular unit in the setting of NE that (i) can help assess the degree or severity of encephalopathy at birth; (ii) can help monitor progression of disease process and efficacy of neuroprotective therapy; (iii) can help assess neurodevelopmental outcome. These biomarkers will be summarized in two categories: 1) Specific biomarkers targeting the neurovascular unit such as glial fibrillary acidic protein (GFAP), ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1), S100B, and neuron specific enolase (NSE) and 2) general inflammatory cytokines, such as interleukin-6 (IL-6), interleukin-1b (IL-1b), and pNF-H, among others.

The immune response after hypoxia-ischemia in a mouse model of preterm brain injury

Background

Preterm brain injury consists primarily of periventricular leukomalacia accompanied by elements of gray-matter injury, and these injuries are associated with cerebral palsy and cognitive impairments. Inflammation is believed to be an important contributing factor to these injuries. The aim of this study was to examine the immune response in a postnatal day (PND) 5 mouse model of preterm brain injury induced by hypoxia-ischemia (HI) that is characterized by focal white and gray-matter injury.

Methods

C57Bl/6 mice at PND 5 were subjected to unilateral HI induced by left carotid artery ligation and subsequent exposure to 10% O₂ for 50 minutes, 70 minutes, or 80 minutes. At seven days post-HI, the white/gray-matter injury was examined. The immune responses in the brain after HI were examined at different time points after HI using RT-PCR and immunohistochemical staining.

Results

HI for 70 minutes in PND 5 mice induced local white-matter injury with focal cortical injury and hippocampal atrophy, features that are similar to those seen in preterm brain injury in human infants. HI for 50 minutes resulted in a small percentage of animals being injured, and HI for 80 minutes produced extensive infarction in multiple brain areas. Various immune responses, including changes in transcription factors and cytokines that are associated with a T-helper (Th)1/Th17-type response, an increased number of CD4+ T-cells, and elevated levels of triggering receptor expressed on myeloid cells 2 (TREM-2) and its adaptor protein DNAX activation protein of 12 kDa (DAP12) were observed using the HI 70 minute preterm brain injury model.

Conclusions

We have established a reproducible model of HI in PND 5 mice that produces consistent local white/gray-matter brain damage that is relevant to preterm brain injury in human infants. This model provides a useful tool for studying preterm brain injury. Both innate and adaptive immune responses are observed after HI, and these show a strong pro-inflammatory Th1/Th17-type bias. Such findings provide a critical foundation for future studies on the mechanism of preterm brain injury and suggest that blocking the Th1/Th17-type immune response might provide neuroprotection after preterm brain injury.

Neurodevelopmental impairment in preterm infants with late-onset infection: not only in extremely preterm infants

Late-onset infection is known to increase the risk of neurodevelopmental impairment in infants born extremely preterm. However, little data is available regarding infants born moderately preterm. The aim of this study was to determine whether late-onset infection in moderately preterm infants (<35 weeks of gestation) was associated with a non-optimal neurodevelopmental outcome at 2 years of age. We analyzed a regional, population-based cohort of infants (LIFT cohort) between January 2003 and December 2009, and we used a propensity score method to reduce bias. Among the 4,618 preterm infants assessed at 2 years, 618 had acquired late-onset infection (13.4 %), and 764 had a non-optimal outcome (16.5 %). The rate of non-optimal outcomes was significantly higher in preterm infants with late-onset infection, irrespective of subgroups of gestational age and birth weight Z-score. After adjusting for the propensity score, the relationship between late-onset infection and non-optimal neurodevelopmental outcome at 2 years among infants born before 35 weeks of gestation remained significant (aOR = 1.3; 95 % CI 1.01-1.7; p = .04).

CONCLUSION

Late-onset infection is associated with poor neurological outcome at 2 years of age among infants born moderately preterm before and after adjustment for the propensity score.