Systemic inflammation, intraventricular hemorrhage, and white matter injury

Mechanisms of hydrocephalus after intraventricular haemorrhage: a review

Intraventricular haemorrhage (IVH) is bleeding within the ventricular system, which in adults is usually mainly secondary to cerebral haemorrhage and subarachnoid haemorrhage. Hydrocephalus is one of the most common complications of intraventricular haemorrhage, which is characterised by an increase in intracranial pressure due to an increased accumulation of cerebrospinal fluid within the ventricular system, and is closely related to the patient's prognosis. Surgical methods such as shunt surgery have been used to treat secondary hydrocephalus in recent years and have been effective in improving the survival and prognosis of patients with hydrocephalus. However, complications such as shunt blockage and intracranial infection are often faced after surgery. Moreover, little is known about the mechanism of hydrocephalus secondary to intraventricular haemorrhage. This review discusses the mechanisms regarding the occurrence of secondary hydrocephalus after intraventricular haemorrhage in adults in terms of blood clot obstruction, altered cerebrospinal fluid dynamics, inflammation, and blood composition.

Neonatal inflammation and its association with asthma and obesity in late childhood among individuals born extremely preterm

BACKGROUND

Asthma and obesity are frequent outcomes among individuals born extremely preterm and are associated with decreased lifespan. Neonatal inflammation is associated with chronic neurodevelopmental disorders; however, it is less studied in association with other later childhood chronic disorders in this population.

METHODS

Fourteen hospitals in 5 U.S. states enrolled 1506 infants born before 28 weeks of gestation in the Extremely Low Gestational Age Newborn cohort in 2004-2014. Neonatal blood spots were collected on postnatal days 1, 7, 14, 21, and 28, and used to measure 14 inflammation-related proteins. Associations were evaluated between high (top quartile) levels of proteins and two chronic health disorders at ages 10 and 15 years: physician-diagnosed asthma and obesity (body mass index ≥95th percentile).

RESULTS

Few associations were found between high levels of 14 inflammation-related proteins, either on a single day or on multiple days, and either asthma or obesity. Similarly, few associations were found in analyses stratified by sex or presence/absence of prenatal inflammation.

CONCLUSIONS

In extremely preterm newborns, systemic elevations of inflammation-related proteins during the neonatal period were not associated with childhood asthma and obesity outcomes at 10 or 15 years of age.

IMPACT

In the large multi-center Extremely Low Gestational Age Newborn (ELGAN) cohort, sustained elevation of neonatal levels of inflammation-related proteins was not consistently associated with asthma or obesity outcomes at 10 or 15 years of age. This finding contrasts with reported associations of perinatal inflammation with obesity at 2 years and neurodevelopmental disorders at 2-15 years in the ELGANs, suggesting that unlike neurodevelopment, peripubertal obesity and asthma may be driven by later childhood exposures. Future research on perinatal mechanisms of childhood asthma and obesity should account for both fetal and later exposures and pathways in addition to inflammation at birth.

Long-Term Neurodevelopmental Impairment among Very Preterm Infants with Sepsis, Meningitis, and Intraventricular Hemorrhage

INTRODUCTION

Sepsis and intraventricular hemorrhage (IVH) are associated with poorer long-term neurodevelopmental outcomes in very preterm infants (VPIs), but less is known about the long-term effect of meningitis and the combined impact of both meningitis and IVH. Our objective was to examine the long-term neurodevelopmental outcomes of VPIs with late onset sepsis and meningitis, with and without IVH, in Canada.

METHODS

We conducted a retrospective cohort study of all infants <29 weeks GA who were admitted to 26 tertiary-level neonatal intensive care units in the Canadian Neonatal Network (CNN) and Canadian Neonatal Follow-Up Network (CNFUN) databases, from January 1, 2010, to December 31, 2016.

RESULTS

Of the 6,322 infants in the cohort, 4,575 had no infection, 1,590 had late onset culture-positive bloodstream infection (CPBSI) only, and 157 had late onset meningitis. There was a significant (p < 0.05) trend of increasing rates of significant neurodevelopmental delay (sNDI) when comparing infants with no infection (sNDI rate 15.0%), late onset CPBSI (sNDI rate 22.9%), and late onset meningitis (sNDI rate 32.0%), even after adjustment for infant characteristics. Similar trends were observed for neurodevelopmental impairment, cerebral palsy, and individual Bayley-III scores <85 for cognitive, language, and motor development. There was an additive effect of IVH in all infant categories, but there was no multiplicative effect between IVH and late onset meningitis.

CONCLUSION

There was an increasing trend of adverse neurodevelopmental outcomes when infants with no infection, late onset CPBSI and late onset meningitis are compared. IVH had an additive effect.

Immuno-epigenetic signature derived in saliva associates with the encephalopathy of prematurity and perinatal inflammatory disorders

BACKGROUND

Preterm birth is closely associated with a phenotype that includes brain dysmaturation and neurocognitive impairment, commonly termed Encephalopathy of Prematurity (EoP), of which systemic inflammation is considered a key driver. DNA methylation (DNAm) signatures of inflammation from peripheral blood associate with poor brain imaging outcomes in adult cohorts. However, the robustness of DNAm inflammatory scores in infancy, their relation to comorbidities of preterm birth characterised by inflammation, neonatal neuroimaging metrics of EoP, and saliva cross-tissue applicability are unknown.

METHODS

Using salivary DNAm from 258 neonates (n = 155 preterm, gestational age at birth 23.28 - 34.84 weeks, n = 103 term, gestational age at birth 37.00 - 42.14 weeks), we investigated the impact of a DNAm surrogate for C-reactive protein (DNAm CRP) on brain structure and other clinically defined inflammatory exposures. We assessed i) if DNAm CRP estimates varied between preterm infants at term equivalent age and term infants, ii) how DNAm CRP related to different types of inflammatory exposure (maternal, fetal and postnatal) and iii) whether elevated DNAm CRP associated with poorer measures of neonatal brain volume and white matter connectivity.

RESULTS

Higher DNAm CRP was linked to preterm status (-0.0107 ± 0.0008, compared with -0.0118 ± 0.0006 among term infants; p < 0.001), as well as perinatal inflammatory diseases, including histologic chorioamnionitis, sepsis, bronchopulmonary dysplasia, and necrotising enterocolitis (OR range |2.00 | to |4.71|, p < 0.01). Preterm infants with higher DNAm CRP scores had lower brain volume in deep grey matter, white matter, and hippocampi and amygdalae (β range |0.185| to |0.218|). No such associations were observed for term infants. Association magnitudes were largest for measures of white matter microstructure among preterms, where elevated epigenetic inflammation associated with poorer global measures of white matter integrity (β range |0.206| to |0.371|), independent of other confounding exposures.

CONCLUSIONS

Inflammatory-related DNAm captures the allostatic load of inflammatory burden in preterm infants. Such DNAm measures complement biological and clinical metrics when investigating the determinants of neurodevelopmental differences.

Systemic Cytokines in Retinopathy of Prematurity

Retinopathy of prematurity (ROP), a vasoproliferative vitreoretinal disorder, is the leading cause of childhood blindness worldwide. Although angiogenic pathways have been the main focus, cytokine-mediated inflammation is also involved in ROP etiology. Herein, we illustrate the characteristics and actions of all cytokines involved in ROP pathogenesis. The two-phase (vaso-obliteration followed by vasoproliferation) theory outlines the evaluation of cytokines in a time-dependent manner. Levels of cytokines may even differ between the blood and the vitreous. Data from animal models of oxygen-induced retinopathy are also valuable. Although conventional cryotherapy and laser photocoagulation are well established and anti-vascular endothelial growth factor agents are available, less destructive novel therapeutics that can precisely target the signaling pathways are required. Linking the cytokines involved in ROP to other maternal and neonatal diseases and conditions provides insights into the management of ROP. Suppressing disordered retinal angiogenesis via the modulation of hypoxia-inducible factor, supplementation of insulin-like growth factor (IGF)-1/IGF-binding protein 3 complex, erythropoietin, and its derivatives, polyunsaturated fatty acids, and inhibition of secretogranin III have attracted the attention of researchers. Recently, gut microbiota modulation, non-coding RNAs, and gene therapies have shown promise in regulating ROP. These emerging therapeutics can be used to treat preterm infants with ROP.

The association of γδT lymphocytes with cystic leukomalacia in premature infants

Background

Periventricular leukomalacia (PVL) is an essential cause of cerebral palsy in preterm infants, and cystic PVL (cPVL) is the most severe form of the disease. The pathogenesis of cPVL is complex, and immune imbalances and inflammatory responses may play an essential role in it.

Objective

This study aimed to investigate the correlation between peripheral blood lymphocyte subsets, especially γδT cells with the pathogenesis of cPVL in preterm infants.

Methods

Peripheral blood from preterm infants with GA < 32 weeks and BW < 1,500 g was used in this study and was collected at 34 weeks corrected gestational age and within 24 h after the diagnosis with cranial MRI or cranial ultrasound. The infants were divided into cPVL groups and control groups. Flow cytometry was used to detect peripheral blood γδT, CD3+, CD4+, CD8+, and the proportion of total lymphocytes. Multiplex cell assays were used to detect the concentration of extracellular serum cytokines IL-6, IL-2, IL-8, IL-17A, IL-10, IL-1RA, eotaxin (CCL11), MCP-1 (CCL2), CXCL1, G-CSF, and IFNγ. A follow-up visit was carried out when the patient was 3 years old.

Results

After correcting for confounding factors, the proportion of peripheral blood γδT in the cPVL group was significantly lower than that in the control group (β: 0.216; 95% CI: 0.058-0.800, P < 0.022). Peripheral blood γδT (AUC: 0.722, P=0.006) and multivariate binary regression model (AUC: 0.865, P < 0.000) have good diagnostic values for cPVL. Peripheral blood γδT has some predictive power for neurodevelopmental outcomes in preterm infants (AUC: 0.743, P = 0.002).

Conclusion

It seems that peripheral blood γδT cells are inversely correlated with cPVL, which is not only a risk factor for cPVL disease but also neurodevelopmental outcomes in preterm infants. However, the causality of cPVL and various lymphocytes is unclear and needs further study.

Role of the Endothelium in Neonatal Diseases

In both fetal and neonatal physiologic and pathologic processes in most organs, endothelial cells are known to play critical roles. Although the endothelium is one of the most ubiquitous cell type in the body, the tight adherence to the blood vessel wall has made it difficult to study their diverse function and structure. In this article, we have reviewed endothelial cell origins and explored their heterogeneity in terms of structure, function, developmental changes, and their role in inflammatory and infectious diseases. We have also attempted to evaluate the untapped therapeutic potentials of endothelial cells in neonatal disease. This article comprises various peer-reviewed studies, including ours, and an extensive database literature search from EMBASE, PubMed, and Scopus.

Placental mediated mechanisms of perinatal brain injury: Evolving inflammation and exosomes

Pregnancy is an inflammatory process that is carefully regulated by the placenta via immunomodulation and cell-to-cell communication of maternal and fetal tissues. Exosomes, types of extracellular vesicles, facilitate the intercellular communication and traffic biologically modifying cargo within the maternal-placental-fetal axis in normal and pathologic pregnancies. Chorioamnionitis is characterized by inflammation of chorioamniotic membranes that produces systemic maternal and fetal inflammatory responses of cytokine dysregulation and has been associated with brain injury and neurodevelopmental disorders. This review focuses on how pathologic placental exosomes propagate acute and chronic inflammation leading to brain injury. The evidence reviewed here highlights the need to investigate exosomes from pathologic pregnancies and those with known brain injury to identify new diagnostics, biomarkers, and potential therapeutic targets.

Decreasing Trend in Incidence of Late Onset Culture Positive Bloodstream Infections but Not Late Onset Meningitis in Preterm Infants <33 Weeks Gestation in Canadian Neonatal Intensive Care Unit

INTRODUCTION

Recent studies reported decreased incidence of late onset sepsis in the neonatal intensive care unit (NICU), but it is unclear whether this is also true for late onset meningitis. Recent reports that both meningitis and intraventricular hemorrhage (IVH) are associated with systemic inflammation also raise questions about an association between the 2.

METHODS

All preterm infants <33 weeks gestational age admitted to CNN NICUs from 2010 to 2018 were included. We compared incidence trends of late onset culture positive bloodstream infection (CPBSI) and late onset meningitis, and examined the association of meningitis and IVH (exposure), after adjustment for potential confounders.

RESULTS

Of 36,573 infants included, 32,198 had no infection, 3,977 had only late onset CPBSI and 398 had late onset meningitis. There was significant decrease in incidence of late onset CPBSI (14%-10%; adjusted odds ratio (AOR) = 0.93; 95% confidence interval [CI] 0.92, 0.95) but not late onset meningitis (1.6%-1.2%; AOR = 0.98; 95% CI 0.94, 1.01). Compared to infants with no IVH grade 3 or above, infants with IVH grade 3, or above had higher odds of late onset meningitis versus no infection (AOR 4.16; 95% CI 3.17, 5.44), and higher odds of late onset meningitis versus late onset CPBSI (AOR 4.11; 95% CI 3.08, 5.50).

CONCLUSIONS

There was a decreasing trend of late onset CPBSI but not late onset meningitis. An association between late onset meningitis and IVH grade 3 or above was observed. Late onset CPBSI and meningitis may have different risk factors and require different prevention strategies.

Systemic Inflammation in the First 2 Weeks after Birth as a Determinant of Physical Growth Outcomes in Hospitalized Infants with Extremely Low Gestational Age

OBJECTIVE

To examine associations of systemic inflammation with growth outcomes at neonatal intensive care unit discharge or transfer among infants with extremely low gestational ages.

STUDY DESIGN

We studied 850 infants at born at 23-27 weeks of gestation. We defined inflammatory protein elevation as the highest quartile of C-reactive protein (CRP), Interleukin (IL)-6, tumor necrosis factor-∝, or IL-8 on postnatal days 1, 7, and 14. We compared z-scores of weight, length, and head circumference at neonatal intensive care unit discharge or transfer between infants with vs without inflammatory protein elevation, adjusting in linear regression for birth size z-score, sex, gestational age, diet, comorbidities, medications, and length of hospitalization.

RESULTS

The mean gestational age was 25 weeks (range, 23-27 weeks) and birth weight z-score 0.14 (range, -2.73 to 3.28). Infants with a high CRP on day 7 had lower weights at discharge or transfer (-0.17 z-score; 95% CI, -0.27 to -0.06) than infants without CRP elevation, with similar results on day 14. Infants with CRP elevation on day 14 were also shorter (-0.21 length z-scores; 95% CI, -0.38 to -0.04), and had smaller head circumferences (-0.18 z-scores; 95% CI, -0.33 to -0.04) at discharge or transfer. IL-6 elevation on day 14 was associated with lower weight (-0.12; 95% CI, -0.22 to -0.02); IL-6 elevation on day 7 was associated with shorter length (-0.27; 95% CI, -0.43 to -0.12). Tumor necrosis factor-∝ and IL-8 elevation on day 14 were associated with a lower weight at discharge or transfer.

CONCLUSIONS

Postnatal systemic inflammation may contribute to impaired nutrient accretion during a critical period in development in infants with extremely low gestational ages.

Preterm Intraventricular Hemorrhage-Induced Inflammatory Response in Human Choroid Plexus Epithelial Cells

Following an intraventricular hemorrhage (IVH), red blood cell lysis and hemoglobin (Hb) oxidation with the release of heme can cause sterile neuroinflammation. In this study, we measured Hb derivates and cellular adhesion molecules ICAM-1 and VCAM-1 with cell-free miRNAs in cerebrospinal fluid (CSF) samples obtained from Grade-III and Grade-IV preterm IVH infants (IVH-III and IVH-IV, respectively) at multiple time points between days 0–60 after the onset of IVH. Furthermore, human choroid plexus epithelial cells (HCPEpiCs) were incubated with IVH and non-IVH CSF (10 v/v %) for 24 h in vitro to investigate the IVH-induced inflammatory response that was investigated via: (i) HMOX1, IL8, VCAM1, and ICAM1 mRNAs as well as miR-155, miR-223, and miR-181b levels by RT-qPCR; (ii) nuclear translocation of the NF-κB p65 subunit by fluorescence microscopy; and (iii) reactive oxygen species (ROS) measurement. We found a time-dependent alteration of heme, IL-8, and adhesion molecules which revealed a prolonged elevation in IVH-IV vs. IVH-III with higher miR-155 and miR-181b expression at days 41–60. Exposure of HCPEpiCs to IVH CSF samples induced HMOX1, IL8, and ICAM1 mRNA levels along with increased ROS production via the NF-κB pathway activation but without cell death, as confirmed by the cell viability assay. Additionally, the enhanced intracellular miR-155 level was accompanied by lower miR-223 and miR-181b expression in HCPEpiCs after CSF treatment. Overall, choroid plexus epithelial cells exhibit an abnormal cell phenotype after interaction with pro-inflammatory CSF of IVH origin which may contribute to the development of later clinical complications in preterm IVH.

Secondary White Matter Injury and Therapeutic Targets After Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is one of the special stroke subtypes with high mortality and mobility. Although the mortality of SAH has decreased by 50% over the past two decades due to advances in neurosurgery and management of neurocritical care, more than 70% of survivors suffer from varying degrees of neurological deficits and cognitive impairments, leaving a heavy burden on individuals, families, and the society. Recent studies have shown that white matter is vulnerable to SAH, and white matter injuries may be one of the causes of long-term neurological deficits caused by SAH. Attention has recently focused on the pivotal role of white matter injury in the pathophysiological processes after SAH, mainly related to mechanical damage caused by increased intracerebral pressure and the metabolic damage induced by blood degradation and hypoxia. In the present review, we sought to summarize the pathophysiology processes and mechanisms of white matter injury after SAH, with a view to providing new strategies for the prevention and treatment of long-term cognitive dysfunction after SAH.

Placental pathology and intraventricular hemorrhage in preterm and small for gestational age infants

OBJECTIVE

The aim of this study was to examine the relationship between chorioamnionitis and vascular malperfusion on placental pathology and intraventricular hemorrhage (IVH) in premature and small for gestational age (SGA) infants.

STUDY DESIGN

A retrospective analysis of 263 infants ≤34 weeks gestation or ≤1800 g and their mothers was conducted by chart review for placental pathology and clinical data from 2014 to 2018. Unadjusted and adjusted odds ratios (OR) for the association of placental pathology with IVH were calculated.

RESULT

Unadjusted OR showed an association between acute chorioamnionitis and IVH, but logistic regression analysis showed a non-significant adjusted OR between acute or chronic chorioamnionitis with IVH. Maternal vascular malperfusion was significantly associated with increased IVH when controlling for confounders.

CONCLUSION

Placental maternal vascular malperfusion is associated with the development of IVH in premature and SGA infants when controlling for other confounders.

Elevated Pro-Inflammatory Cell-Free MicroRNA Levels in Cerebrospinal Fluid of Premature Infants after Intraventricular Hemorrhage

Intraventricular hemorrhage (IVH) represents a high risk of neonatal mortality and later neurodevelopmental impairment in prematurity. IVH is accompanied with inflammation, hemolysis, and extracellular hemoglobin (Hb) oxidation. However, microRNA (miRNA) expression in cerebrospinal fluid (CSF) of preterm infants with IVH has been unknown. Therefore, in the present study, candidate pro-inflammatory cell-free miRNAs were analyzed in CSF samples from 47 preterm infants with grade III or IV IVH vs. clinical controls (n = 14). miRNAs were quantified by RT-qPCR, normalized to “spike-in” cel-miR-39. Oxidized Hb and total heme levels were determined by spectrophotometry as well as IL-8, VCAM-1, ICAM-1, and E-selectin concentrations by ELISA. To reveal the origin of the investigated miRNAs, controlled hemolysis experiments were performed in vitro; in addition, human choroid plexus epithelial cell (HCPEpiC) cultures were treated with metHb, ferrylHb, heme, or TNF-α to replicate IVH-triggered cellular conditions. Levels of miR-223, miR-155, miR-181b, and miR-126 as well as Hb metabolites along with IL-8 were elevated in CSF after the onset of IVH vs. controls. Significant correlations were observed among the miRNAs, oxidized Hb forms, and the soluble adhesion molecules. During the post-IVH follow-up, attenuated expression of miRNAs and protein biomarkers in CSF was observed upon elimination of Hb metabolites. These miRNAs remained unaffected by a series of artificially induced hemolysis, which excluded red blood cells as their origin, while stimulation of HCPEpiCs with oxidized Hb fractions and heme resulted in increased extracellular miRNA levels in the cell culture supernatant. Overall, the hemorrhage-induced CSF miRNAs reflected inflammatory conditions as potential biomarkers in preterm IVH.

Lipopolysaccharide-induced changes in the neurovascular unit in the preterm fetal sheep brain

Background

Exposure to inflammation during pregnancy can predispose to brain injury in premature infants. In the present study, we investigated the effects of prolonged exposure to inflammation on the cerebrovasculature of preterm fetal sheep.

Methods

Chronically instrumented fetal sheep at 103–104 days of gestation (full term is ~ 147 days) received continuous low-dose lipopolysaccharide (LPS) infusions (100 ng/kg over 24 h, followed by 250 ng/kg/24 h for 96 h plus boluses of 1 μg LPS at 48, 72, and 96 h) or the same volume of normal saline (0.9%, w/v). Ten days after the start of LPS exposure at 113–114 days of gestation, the sheep were killed, and the fetal brain perfused with formalin in situ. Vessel density, pericyte and astrocyte coverage of the blood vessels, and astrogliosis in the cerebral cortex and white matter were determined using immunohistochemistry.

Results

LPS exposure reduced (P < 0.05) microvascular vessel density and pericyte vascular coverage in the cerebral cortex and white matter of preterm fetal sheep, and increased the activation of perivascular astrocytes, but decreased astrocytic vessel coverage in the white matter.

Conclusions

Prolonged exposure to LPS in preterm fetal sheep resulted in decreased vessel density and neurovascular remodeling, suggesting that chronic inflammation adversely affects the neurovascular unit and, therefore, could contribute to long-term impairment of brain development.

The Role of Hemoglobin Oxidation Products in Triggering Inflammatory Response Upon Intraventricular Hemorrhage in Premature Infants

Intraventricular hemorrhage (IVH) is a frequent complication of prematurity that is associated with high neonatal mortality and morbidity. IVH is accompanied by red blood cell (RBC) lysis, hemoglobin (Hb) oxidation, and sterile inflammation. Here we investigated whether extracellular Hb, metHb, ferrylHb, and heme contribute to the inflammatory response after IVH. We collected cerebrospinal fluid (CSF) (n = 20) from premature infants with grade III IVH at different time points after the onset of IVH. Levels of Hb, metHb, total heme, and free heme were the highest in CSF samples obtained between days 0 and 20 after the onset of IVH and were mostly non-detectable in CSF collected between days 41 and 60 of post-IVH. Besides Hb monomers, we detected cross-linked Hb dimers and tetramers in post-IVH CSF samples obtained in days 0–20 and 21–40, but only Hb tetramers were present in CSF samples obtained after 41–60 days. Vascular cell adhesion molecule-1 (VCAM-1) and interleukin-8 (IL-8) levels were higher in CSF samples obtained between days 0 and 20 than in CSF collected between days 41 and 60 of post-IVH. Concentrations of VCAM-1, intercellular adhesion molecule-1 (ICAM-1), and IL-8 strongly correlated with total heme levels in CSF. Applying the identified heme sources on human brain microvascular endothelial cells revealed that Hb oxidation products and free heme contribute to the inflammatory response. We concluded that RBC lysis, Hb oxidation, and heme release are important components of the inflammatory response in IVH. Pharmacological interventions targeting cell-free Hb, Hb oxidation products, and free heme could have potential to limit the neuroinflammatory response following IVH.

Hemoglobin oxidation generates globin-derived peptides in atherosclerotic lesions and intraventricular hemorrhage of the brain, provoking endothelial dysfunction

The lysis of red blood cells was shown to occur in human ruptured atherosclerotic lesions and intraventricular hemorrhage (IVH) of the brain. Liberated cell-free hemoglobin was found to undergo oxidation in both pathologies. We hypothesize that hemoglobin-derived peptides are generated during hemoglobin oxidation both in complicated atherosclerotic lesions and IVH of the brain, triggering endothelial cell dysfunction. Oxidized hemoglobin and its products were followed with spectrophotometry, LC-MS/MS analysis and detection of the cross-linking of globin chains in complicated atherosclerotic lesions of the human carotid artery and the hemorrhaged cerebrospinal liquid of preterm infants. The vascular pathophysiologic role of oxidized hemoglobin and the resultant peptides was assessed by measuring endothelial integrity, the activation of endothelial cells and the induction of proinflammatory genes. Peptide fragments of hemoglobin (VNVDEVGGEALGRLLVVYPWTQR, LLVVYPWTQR, MFLSFPTTK, VGAHAGEYGAELERMFLSFPTTK, and FLASVSTVLTSKYR) were identified in ruptured atherosclerotic lesions and in IVH of the human brain. Fragments resulting from the oxidation of hemoglobin were accompanied by the accumulation of ferryl hemoglobin. Similar to complicated atherosclerotic lesions of the human carotid artery, a high level of oxidized and cross-linked hemoglobin was observed in the cerebrospinal fluid after IVH. Haptoglobin inhibited hemoglobin fragmentation provoked by peroxide. The resultant peptides failed to bind haptoglobin or albumin. Peptides derived from hemoglobin oxidation and ferryl hemoglobin induced intercellular gap formation, decreased junctional resistance in the endothelium, and enhanced monocyte adhesion to endothelial cells. Enhanced expression of TNF and the activation of NLRP3 and CASP1 followed by the increased generation of IL-1β and nuclear translocation of the NF-κβ transcription factor occurred in response to hemoglobin-derived peptides, and ferryl hemoglobin in endothelium was upregulated in both pathologies. We conclude that the oxidation of hemoglobin in complicated atherosclerotic lesions and intraventricular hemorrhage of the brain generates peptide fragments and ferryl hemoglobin with the potential to trigger endothelial cell dysfunction.

Early changes in pro-inflammatory cytokine levels in neonates with encephalopathy are associated with remote epilepsy

BACKGROUND

Neonatal seizures are associated with adverse neurologic sequelae including epilepsy in childhood. Here we aim to determine whether levels of cytokines in neonates with brain injury are associated with acute symptomatic seizures or remote epilepsy.

METHODS

This is a cohort study of term newborns with encephalopathy at UCSF between 10/1993 and 1/2000 who had dried blood spots. Maternal, perinatal/postnatal, neuroimaging, and epilepsy variables were abstracted by chart review. Logistic regression was used to compare levels of cytokines with acute seizures and the development of epilepsy.

RESULTS

In a cohort of 26 newborns with neonatal encephalopathy at risk for hypoxic ischemic encephalopathy with blood spots for analysis, diffuse alterations in both pro- and anti-inflammatory cytokine levels were observed between those with (11/28, 39%) and without acute symptomatic seizures. Seventeen of the 26 (63%) patients had >2 years of follow-up and 4/17 (24%) developed epilepsy. Higher levels of pro-inflammatory cytokines IL-6 and TNF-α within the IL-1β pathway were significantly associated with epilepsy.

CONCLUSIONS

Elevations in pro-inflammatory cytokines in the IL-1β pathway were associated with later onset of epilepsy. Larger cohort studies are needed to confirm the predictive value of these circulating biomarkers.

An Integrative Review of Cytokine/Chemokine Predictors of Neurodevelopment in Preterm Infants

Preterm infants are at risk of brain injury and poor neurodevelopmental outcomes including impairments in cognition, behavioral functioning, sensory perception, and motor performance. Systemic inflammation has been identified as an important, potentially modifiable precursor of neurologic and neurodevelopmental impairments. Inflammation is typically measured by quantifying circulating cytokines and chemokines. However, it is unclear which specific cytokines/chemokines most consistently predict neurodevelopment in preterm infants. In this integrative review, we evaluated and analyzed the literature (N = 37 publications) to determine the cytokines/chemokines most predictive of neurodevelopment in preterm infants, the optimal timing for these measurements, and the ideal source for collecting cytokines/chemokines. Synthesis of the findings of these studies revealed that interleukin (IL)-6, IL-1β, IL-8, and tumor necrosis factor (TNF)-α collected during the first 3 weeks of life are most predictive of subsequent neurodevelopment. Methodological variation among studies hinders more specific analysis, including the evaluation of cytokine thresholds and meta-analyses, that would allow for the use of cytokines/chemokines to predict neurodevelopment. Future research should focus on identifying explicit cytokine values, specifically for IL-6, IL-1β, IL-8, and TNF-α, that are most predictive for identifying preterm infants most at risk of impairment, keeping in mind that longitudinal measures of cytokines/chemokines may be more predictive of future outcomes than single-time point measures.

Serum Amyloid A Protein as a Potential Biomarker for Severity and Acute Outcome in Traumatic Brain Injury

Traumatic brain injury (TBI) causes a wide variety of neuroinflammatory events. These neuroinflammatory events depend, to a greater extent, on the severity of the damage. Our previous studies have shown that the liver produces serum amyloid A (SAA) at high levels in the initial hours after controlled cortical impact (CCI) injury in mice. Clinical studies have reported detectable SAA in the plasma of brain injury patients, but it is not clear if SAA levels depend on TBI severity. To evaluate this question, we performed a mild to severe CCI injury in wild-type mice. We collected blood samples and brains at 1, 3, and 7 days after injury for protein detection by western blotting, enzyme-linked immunosorbent assay, or immunohistochemical analysis. Our results showed that severe CCI injury compared to mild CCI injury or sham mice caused an increased neuronal death, larger lesion volume, increased microglia/macrophage density, and augmented neutrophil infiltration. Furthermore, we found that the serum levels of SAA protein ascended in the blood in correlation with high neuroinflammatory and neurodegenerative responses. Altogether, these results suggest that serum SAA may be a novel neuroinflammation-based, and severity-dependent, biomarker for acute TBI.

Elevated protein concentrations in newborn blood and the risks of autism spectrum disorder, and of social impairment, at age 10 years among infants born before the 28th week of gestation

Among the 1 of 10 children who are born preterm annually in the United States, 6% are born before the third trimester. Among children who survive birth before the 28th week of gestation, the risks of autism spectrum disorder (ASD) and non-autistic social impairment are severalfold higher than in the general population. We examined the relationship between top quartile inflammation-related protein concentrations among children born extremely preterm and ASD or, separately, a high score on the Social Responsiveness Scale (SRS total score ≥65) among those who did not meet ASD criteria, using information only from the subset of children whose DAS-II verbal or non-verbal IQ was ≥70, who were assessed for ASD, and who had proteins measured in blood collected on ≥2 days (N = 763). ASD (N = 36) assessed at age 10 years is associated with recurrent top quartile concentrations of inflammation-related proteins during the first post-natal month (e.g., SAA odds ratio (OR); 95% confidence interval (CI): 2.5; 1.2-5.3) and IL-6 (OR; 95% CI: 2.6; 1.03-6.4)). Top quartile concentrations of neurotrophic proteins appear to moderate the increased risk of ASD associated with repeated top quartile concentrations of inflammation-related proteins. High (top quartile) concentrations of SAA are associated with elevated risk of ASD (2.8; 1.2-6.7) when Ang-1 concentrations are below the top quartile, but not when Ang-1 concentrations are high (1.3; 0.3-5.8). Similarly, high concentrations of TNF-α are associated with heightened risk of SRS-defined social impairment (N = 130) (2.0; 1.1-3.8) when ANG-1 concentrations are not high, but not when ANG-1 concentrations are elevated (0.5; 0.1-4.2).

Cognitive Development and Quality of Life Associated With BPD in 10-Year-Olds Born Preterm

OBJECTIVES

To compare neurocognitive, language, executive function, academic achievement, neurologic and behavioral outcomes, and quality of life at age 10 years in children born extremely preterm who developed bronchopulmonary dysplasia (BPD) to children who did not develop BPD.

METHODS

The Extremely Low Gestational Age Newborns study population included 863 children born extremely preterm whose BPD status before discharge was known had an IQ (Differential Ability Scales II [DAS II]) assessment at 10 years. We evaluated the association of BPD with any cognitive (DAS II), executive function (NEuroPSYchological Assessment II), academic achievement (Wechsler Individual Achievement Test-III and Oral and Written Language Scales [OWLS]) as well as social dysfunctions (Social Responsiveness Scale). We used logistic regression models, adjusting for potential confounding factors, to assess the strength of association between the severity of BPD and each outcomes.

RESULTS

Three hundred and seventy-two (43%) children were oxygen-dependent at 36 weeks postconception age, whereas an additional 78 (9%) were also oxygen- and ventilator-dependent. IQ scores 2 or more SDs below the expected mean (ie, z scores ≤-2) occurred twice as commonly among children who had BPD as among those who did not. Children with severe BPD consistently had the lowest scores on DAS II, OWLS, Wechsler Individual Achievement Test-III, NEuroPSYchological Assessment II, and Social Responsiveness Scale assessments.

CONCLUSIONS

Among 10-year-old children born extremely preterm, those who had BPD were at increased risk of cognitive, language, and executive dysfunctions; academic achievement limitations; social skill deficits; and low scores on assessments of health-related quality of life.

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

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

WHAT THIS PAPER ADDS

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

Bacterial N-formyl Peptides Reduce PMA- and Escherichia coli-Induced Neutrophil Respiratory Burst in Term Neonates and Adults

Neutrophil migration and respiratory burst are the prerequisite for efficient first line defense against invading microorganisms. However, migration and respiratory burst can be compromised in adults and especially in newborn infants, where sustained neutrophil accumulation, uncontrolled burst and reduced scavenging of ROS might cause inadvertent tissue damage due to uncontrolled inflammation. The aim of this study was to investigate the modulatory effect of the chemoattractants formyl-methionyl-leucyl-phenylalanine (fMLP) and IL-8 on respiratory burst in neutrophils from term newborn infants and adults. Whole blood from the umbilical cord of 17 healthy term newborn infants delivered by caesarean section and from 17 healthy adults as reference was preincubated with fMLP or IL-8 and stimulated with PMA or Escherichia coli bacteria. Respiratory burst was quantified by flow cytometry analysis of dihydrorhodamine 123 fluorescence. fMLP reduced the PMA-induced respiratory burst of neutrophils from newborn infants and adults by 12% and 21%, respectively (P < 0.05). E. coli-induced burst was also reduced by fMLP in neutrophils from newborn infants (10%; P < 0.01) and adults (6%; P < 0.05). No such changes were observed with IL-8. Similar respiratory burst in response to single stimulus with PMA or E. coli was observed in both newborn infants and adults. fMLP reduced PMA- and E. coli-induced respiratory burst of neutrophils in whole blood from term newborn infants as well as in adults. The reduced respiratory burst by fMLP might be a mechanism to reduce the detrimental effects of uncontrolled inflammation during neutrophil migration.

Maternal dendrimer-based therapy for inflammation-induced preterm birth and perinatal brain injury

Preterm birth is a major risk factor for adverse neurological outcomes in ex-preterm children, including motor, cognitive, and behavioral disabilities. N-acetyl-L-cysteine therapy has been used in clinical studies; however, it requires doses that cause significant side effects. In this study, we explore the effect of low dose N-acetyl-L-cysteine therapy, delivered using a targeted, systemic, maternal, dendrimer nanoparticle (DNAC), in a mouse model of intrauterine inflammation. Our results demonstrated that intraperitoneal maternal DNAC administration significantly reduced the preterm birth rate and altered placental immune profile with decreased CD8⁺ T-cell infiltration. Furthermore, we demonstrated that DNAC improved neurobehavioral outcomes and reduced fetal neuroinflammation and long-term microglial activation in offspring. Our study is the first to provide evidence for the role of CD8⁺ T-cell in the maternal-fetal interface during inflammation and further support the efficacy of DNAC in preventing preterm birth and prematurity-related outcomes.

Early postnatal exposure to intermittent hypoxia in rodents is proinflammatory, impairs white matter integrity, and alters brain metabolism

BackgroundPreterm infants are frequently exposed to intermittent hypoxia (IH) associated with apnea and periodic breathing that may result in inflammation and brain injury that later manifests as cognitive and executive function deficits. We used a rodent model to determine whether early postnatal exposure to IH would result in inflammation and brain injury.MethodsRat pups were exposed to IH from P2 to P12. Control animals were exposed to room air. Cytokines were analyzed in plasma and brain tissue at P13 and P18. At P20-P22, diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) were performed.ResultsPups exposed to IH had increased plasma Gro/CXCL1 and cerebellar IFN-γ and IL-1β at P13, and brainstem enolase at P18. DTI showed a decrease in FA and AD in the corpus callosum (CC) and cingulate gyrus, and an increase in RD in the CC. MRS revealed decreases in NAA/Cho, Cr, Tau/Cr, and Gly/Cr; increases in TCho and GPC in the brainstem; and decreases in NAA/Cho in the hippocampus.ConclusionsWe conclude that early postnatal exposure to IH, similar in magnitude to that experienced in human preterm infants, is associated with evidence for proinflammatory changes, decreases in white matter integrity, and metabolic changes consistent with hypoxia.

Antecedents and correlates of blood concentrations of neurotrophic growth factors in very preterm newborns

AIM

To identify the antecedents and very early correlates of low concentrations of neurotrophic growth factors in the blood of extremely preterm newborns during the first postnatal month.

METHODS

Using an immunobead assay, we measured the concentrations of neurotrophin 4 (NT4), brain-derived neurotrophic factor (BDNF), and basic fibroblast growth factor (bFGF) in blood spots collected on postnatal days 1 (N=1062), 7 (N=1087), 14 (N=989), 21 (N=940) and 28 (N=880) from infants born before the 28th week of gestation. We then sought the correlates of measurements in the top and bottom quartiles for gestational age and day the specimen was collected.

RESULTS

The concentrations of 2 neurotrophic proteins, NT4 and BDNF, were low among children delivered for medical (maternal or fetal) indications, and among those who were growth restricted. Children who had top quartile concentrations of NT4, BDNF, and bFGF tended to have elevated concentrations of inflammation-related proteins that day. This pattern persisted for much of the first postnatal month.

CONCLUSIONS

Delivery for medical indications and fetal growth restriction are associated with a relative paucity of NT4 and BDNF concentrations during the first 24 h after very preterm birth. Elevated blood concentrations of NT4, BDNF, and bFGF tended to co-occur with indicators of systemic inflammation on the same day.

Leading causes of preterm delivery as risk factors for intraventricular hemorrhage in very preterm infants: results of the EPIPAGE 2 cohort study

BACKGROUND

Intraventricular hemorrhage is a major risk factor for neurodevelopmental disabilities in preterm infants. However, few studies have investigated how pregnancy complications responsible for preterm delivery are related to intraventricular hemorrhage.

OBJECTIVE

We sought to investigate the association between the main causes of preterm delivery and intraventricular hemorrhage in very preterm infants born in France during 2011 between 22-31 weeks of gestation.

STUDY DESIGN

The study included 3495 preterm infants from the national EPIPAGE 2 cohort study who were admitted to neonatal intensive care units and had at least 1 cranial ultrasound assessment. The primary outcome was grade I-IV intraventricular hemorrhage according to the Papile classification. Multinomial logistic regression models were used to study the relationship between risk of intraventricular hemorrhage and the leading causes of preterm delivery: vascular placental diseases, isolated intrauterine growth retardation, placental abruption, preterm labor, and premature rupture of membranes, with or without associated maternal inflammatory syndrome.

RESULTS

The overall frequency of grade IV, III, II, and I intraventricular hemorrhage was 3.8% (95% confidence interval, 3.2-4.5), 3.3% (95% confidence interval, 2.7-3.9), 12.1% (95% confidence interval, 11.0-13.3), and 17.0% (95% confidence interval, 15.7-18.4), respectively. After adjustment for gestational age, antenatal magnesium sulfate therapy, level of care in the maternity unit, antenatal corticosteroids, and chest compressions, infants born after placental abruption had a higher risk of grade IV and III intraventricular hemorrhage compared to those born under placental vascular disease conditions, with adjusted odds ratios of 4.3 (95% confidence interval, 1.1-17.0) and 4.4 (95% confidence interval, 1.1-17.6), respectively. Similarly, preterm labor with concurrent inflammatory syndrome was associated with an increased risk of grade IV intraventricular hemorrhage (adjusted odds ratio, 3.4; 95% confidence interval, 1.1-10.2]). Premature rupture of membranes did not significantly increase the risk.

CONCLUSION

Relationships between the causes of preterm birth and intraventricular hemorrhage were limited to specific and rare cases involving acute hypoxia-ischemia and/or inflammation. While the emergent nature of placental abruption would challenge any attempts to optimize management, the prenatal care offered during preterm labor could be improved.

Neutralizing anti-interleukin-1β antibodies reduce ischemia-related interleukin-1β transport across the blood-brain barrier in fetal sheep

Hypoxic ischemic insults predispose to perinatal brain injury. Pro-inflammatory cytokines are important in the evolution of this injury. Interleukin-1β (IL-1β) is a key mediator of inflammatory responses and elevated IL-1β levels in brain correlate with adverse neurodevelopmental outcomes after brain injury. Impaired blood-brain barrier (BBB) function represents an important component of hypoxic-ischemic brain injury in the fetus. In addition, ischemia-reperfusion increases cytokine transport across the BBB of the ovine fetus. Reducing pro-inflammatory cytokine entry into brain could represent a novel approach to attenuate ischemia-related brain injury. We hypothesized that infusions of neutralizing IL-1β monoclonal antibody (mAb) reduce IL-1β transport across the BBB after ischemia in the fetus. Fetal sheep were studied 24-h after 30-min of carotid artery occlusion. Fetuses were treated with placebo- or anti-IL-1β mAb intravenously 15-min and 4-h after ischemia. Ovine IL-1β protein expressed from IL-1β pGEX-2T vectors in Escherichia coli (E. coli) BL-21 cells was produced, purified, and radiolabeled with ¹²⁵I. BBB permeability was quantified using the blood-to-brain transfer constant (K_i) with ¹²⁵I-radiolabeled-IL-1β. Increases in anti-IL-1β mAb were observed in the brain of the mAb-treated group (P<0.001). Blood-to-brain transport of ¹²⁵I-IL-1β was lower (P<0.04) across brain regions in the anti-IL-1β mAb-treated than placebo-treated ischemic fetuses. Plasma ¹²⁵I-IL-1β counts were higher (P<0.001) in the anti-IL-1β mAb- than placebo-treated ischemic fetuses. Systemic infusions of anti-IL-1β mAb reduce IL-1β transport across the BBB after ischemia in the ovine fetus. Our findings suggest that conditions associated with increases in systemic pro-inflammatory cytokines and neurodevelopmental impairment could benefit from an anti-cytokine therapeutic strategy.

Circulating Inflammatory-Associated Proteins in the First Month of Life and Cognitive Impairment at Age 10 Years in Children Born Extremely Preterm

OBJECTIVES

To evaluate whether in children born extremely preterm, indicators of sustained systemic inflammation in the first month of life are associated with cognitive impairment at school age.

STUDY DESIGN

A total of 873 of 966 eligible children previously enrolled in the multicenter Extremely Low Gestational Age Newborn Study from 2002 to 2004 were evaluated at age 10 years. We analyzed the relationship between elevated blood concentrations of inflammation-associated proteins in the first 2 weeks ("early elevations"; n = 812) and the third and fourth week ("late elevations"; n = 532) of life with neurocognition.

RESULTS

Early elevations of C-reactive protein, tumor necrosis factor-α, interleukin (IL)-8, intercellular adhesion molecule (ICAM)-1, and erythropoietin were associated with IQ values >2 SD below the expected mean (ORs: 2.0-2.3) and with moderate to severe cognitive impairment on a composite measure of IQ and executive function (ORs: 2.1-3.6). Additionally, severe cognitive impairment was associated with late protein elevations of C-reactive protein (OR: 4.0; 95% CI 1.5, 10), IL-8 (OR: 5.0; 1.9, 13), ICAM-1 (OR: 6.5; 2.6, 16), vascular endothelial growth factor-receptor 2 (OR: 3.2; 1.2, 8.3), and thyroid-stimulating hormone (OR: 3.1; 1.3, 7.3). Moderate cognitive impairment was most strongly associated with elevations of IL-8, ICAM-1, and vascular endothelial growth factor-receptor 2. When 4 or more inflammatory proteins were elevated early, the risk of having an IQ <70 and having overall impaired cognitive ability was more than doubled (ORs: 2.1-2.4); the presence of 4 or more inflammatory protein elevated late was strongly linked to adverse cognitive outcomes (ORs: 2.9-4.8).

CONCLUSIONS

Extremely preterm children who had sustained elevations of inflammation-related proteins in the first postnatal month are more likely than extremely preterm peers without such elevations to have cognitive impairment at 10 years.

Antenatal glucocorticoids and neonatal inflammation-associated proteins

BACKGROUND

To date, studies of the relationship between antenatal glucocorticoids (AGC) and neonatal inflammation in preterm newborns have been largely limited to umbilical cord blood specimens.

AIM

To explore the association between exposure to antenatal glucocorticoids and concentrations of inflammation-related proteins in whole blood collected from very preterm newborns at multiple times during the first postnatal month.

METHODS

We measured the protein concentrations on postnatal day 1 (N=1118), day 7 (N=1138), day 14 (N=1030), day 21 (N=936) and day 28 (N=877) from infants born before the 28th week of gestation and explored the relationship between antenatal steroid receipt and protein concentrations in the highest and lowest quartiles. The creation of multinomial logistic regression models (adjusted for potential confounders) allowed us calculate odds ratios and 95% confidence intervals.

RESULTS

Twenty of 420 assessments [21 (proteins)×2 (exposure levels: partial and full)×2 (quartile levels: top and bottom)×5 (days)] were statistically significant without any cohesive pattern.

CONCLUSION

Among infants born before 28 weeks of gestational age, neither full, nor partial courses of antenatal glucocorticoids have a sustained anti-inflammatory effect.

Early Postnatal Lipopolysaccharide Exposure Leads to Enhanced Neurogenesis and Impaired Communicative Functions in Rats

Perinatal infection is a well-identified risk factor for a number of neurodevelopmental disorders, including brain white matter injury (WMI) and Autism Spectrum Disorders (ASD). The underlying mechanisms by which early life inflammatory events cause aberrant neural, cytoarchitectural, and network organization, remain elusive. This study is aimed to investigate how systemic lipopolysaccharide (LPS)-induced neuroinflammation affects microglia phenotypes and early neural developmental events in rats. We show here that LPS exposure at early postnatal day 3 leads to a robust microglia activation which is characterized with mixed microglial proinflammatory (M1) and anti-inflammatory (M2) phenotypes. More specifically, we found that microglial M1 markers iNOS and MHC-II were induced at relatively low levels in a regionally restricted manner, whereas M2 markers CD206 and TGFβ were strongly upregulated in a sub-set of activated microglia in multiple white and gray matter structures. This unique microglial response was associated with a marked decrease in naturally occurring apoptosis, but an increase in cell proliferation in the subventricular zone (SVZ) and the dentate gyrus (DG) of hippocampus. LPS exposure also leads to a significant increase in oligodendrocyte lineage population without causing discernible hypermyelination. Moreover, LPS-exposed rats exhibited significant impairments in communicative and cognitive functions. These findings suggest a possible role of M2-like microglial activation in abnormal neural development that may underlie ASD-like behavioral impairments.

A First Tetraplex Assay for the Simultaneous Quantification of Total α-Synuclein, Tau, β-Amyloid42 and DJ-1 in Human Cerebrospinal Fluid

The quantification of four distinct proteins (α-synuclein, β-amyloid_1-42, DJ-1, and total tau) in cerebrospinal fluid (CSF) has been proposed as a laboratory-based platform for the diagnosis of Parkinson’s disease (PD) and Alzheimer’s disease (AD). While there is some clinical utility in measuring these markers individually, their usage in routine clinical testing remains challenging, in part due to substantial overlap of concentrations between healthy controls and diseased subjects. In contrast, measurement of different analytes in a single sample from individual patients in parallel appears to considerably improve the accuracy of AD or PD diagnosis. Here, we report the development and initial characterization of a first, electrochemiluminescence-based multiplex immunoassay for the simultaneous quantification of all four proteins (‘tetraplex’) in as little as 50 μl of CSF. In analytical performance experiments, we assessed its sensitivity, spike-recovery rate, parallelism and dilution linearity as well as the intra- and inter-assay variability. Using our in-house calibrators, we recorded a lower limit of detection for α-synuclein, β-amyloid₄₂, DJ-1, and t-tau of 1.95, 1.24, 5.63, and 4.05 pg/ml, respectively. The corresponding, linear concentration range covered >3 orders of magnitude. In diluted CSF samples (up to 1:4), spike-recovery rates ranged from a low of 55% for β-amyloid₄₂ to a high of 98% for DJ-1. Hillslopes ranged from 1.03 to 1.30, and inter-assay variability demonstrated very high reproducibility. Our newly established tetraplex assay represents a significant technical advance for fluid-based biomarker studies in neurodegenerative disorders allowing the simultaneous measurement of four pivotal makers in single CSF specimens. It provides exceptional sensitivity, accuracy and speed.

Antecedents of cerebral palsy according to severity of motor impairment

INTRODUCTION

The purpose of this study was to determine whether antecedents and neuroimaging patterns vary according to the severity of motor impairment in children with cerebral palsy.

MATERIAL AND METHODS

A population-based study in which all 309 term-born children with spastic and dyskinetic cerebral palsy born between 1983 and 1994 and 618 matched controls were studied. Antecedents were retrieved from obstetric records. Information on neuroimaging was retrieved from the cerebral palsy Register of Western Sweden. Cases were grouped by severity of motor impairment: mild (walks without aids), moderate (walks with aids) or severe (dependent on wheelchair). Binary logistic regression, the Cochran-Armitage test for trends, interaction analyses and interrelationship analyses were performed.

RESULTS

Antecedents associated with mild motor impairment were antepartum (placental weight, maternal weight and antibiotic therapy) or intrapartum and postpartum adverse events (meconium-stained amniotic fluid, low Apgar score, admission to neonatal intensive care unit and neonatal encephalopathy). Antecedents associated with severe motor impairment were antepartum (congenital infection, small head circumference and brain maldevelopment) or intrapartum and postpartum (emergency cesarean section and maternal antibiotic therapy). Comparisons between mild and severe motor impairment revealed congenital infection, maldevelopment, neonatal encephalopathy and meconium aspiration syndrome significantly more often in the group with severe motor impairment (p < 0.05). White matter injury was the most common neuroimaging pattern in mild motor impairment, whereas maldevelopment and cortical/subcortical lesions were most common in the severe motor impairment group.

CONCLUSIONS

Our results suggest a variation in antecedents associated with cerebral palsy, related to severity of motor impairment. Timing of antecedents corresponded to neuroimaging patterns.

Role of selected cytokines in the etiopathogenesis of intraventricular hemorrhage in preterm newborns

Proinflammatory cytokines are essential mediators and indicators of an inflammatory process occurring in the body. Their physiological role is to stimulate the immune response, yet their excessive propagation and interaction with cells outside the immune system may be linked to the risk of organ damage. This is specifically important in the case of immature tissues of fetuses and prematurely born infants. Analysis of the concentrations of specific cytokines in different compartments makes it possible to assess the risk of premature birth, preterm rupture of the membranes, and to determine an existing intrauterine infection. The purpose of this paper is to summarize the existing research concerning the relationships between the concentrations of specific proinflammatory cytokines in different compartments (maternal blood serum, amniotic fluid, umbilical cord blood, arterial and venous blood, and cerebrospinal fluid of the newborn) and the risk of intraventricular hemorrhage (IVH) and the degree of its severity. The paper takes also into account the assessment of the usefulness of cytokines as biomarkers for IVH and its complications (posthemorrhagic hydrocephalus, white matter injury).

Surgical Necrotizing Enterocolitis versus Spontaneous Intestinal Perforation in White Matter Injury on Brain Magnetic Resonance Imaging

BACKGROUND

White matter injury (WMI) is the most common form of brain injury in preterm infants. It could be induced by a systemic inflammatory response in preterm infants.

OBJECTIVES

We hypothesized that surgical necrotizing enterocolitis (surgNEC) results in more severe WMI than spontaneous intestinal perforation (SIP) on brain magnetic resonance imaging (MRI) at term-equivalent age (TEA).

METHODS

The medical records of 33 preterm infants born at less than 32 weeks of gestation who underwent surgery due to either NEC or SIP were reviewed retrospectively. White matter abnormality (WMA) on brain MRI was scored according to the diagnosis of surgNEC or SIP.

RESULTS

Nine patients were diagnosed with SIP and 24 with surgNEC. The median (range) gestational age of the SIP and surgNEC groups was 26+6 (23+3-27+6) and 25+5 weeks (23+3-31+2), respectively (p = 0.454). There were no differences in 1- and 5-min Apgar scores, mode of delivery, use of antenatal steroids, histologic chorioamnionitis, or incidence of respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD) between the two groups. Males were more prevalent in the surgNEC group (75.0 vs. 33.3%, p = 0.044), and the incidence of sepsis was higher in the surgNEC group than in the SIP group (75.0 vs. 33.3%, p = 0.044). Multivariate regression showed that the difference in WMA scores between the two groups remained significant (estimated difference = 2.418; 95% CI 0.107-4.729).

CONCLUSION

In preterm infants at less than 32 weeks of gestation, those with surgNEC showed more severe WMI than infants with SIP on brain MRI at TEA.

A "multi-hit" model of neonatal white matter injury: cumulative contributions of chronic placental inflammation, acute fetal inflammation and postnatal inflammatory events

OBJECTIVE

We sought to determine whether cumulative evidence of perinatal inflammation was associated with increased risk in a "multi-hit" model of neonatal white matter injury (WMI).

METHODS

This retrospective cohort study included very preterm (gestational ages at delivery <32 weeks) live-born singleton neonates delivered at Hutzel Women's Hospital, Detroit, MI, from 2006 to 2011. Four pathologists blinded to clinical diagnoses and outcomes performed histological examinations according to standardized protocols. Neurosonography was obtained per routine clinical care. The primary indicator of WMI was ventriculomegaly (VE). Neonatal inflammation-initiating illnesses included bacteremia, surgical necrotizing enterocolitis, other infections, and those requiring mechanical ventilation.

RESULTS

A total of 425 live-born singleton neonates delivered before the 32nd week of gestation were included. Newborns delivered of pregnancies affected by chronic chorioamnionitis who had histologic evidence of an acute fetal inflammatory response were at increased risk of VE, unlike those without funisitis, relative to referent newborns without either condition, adjusting for gestational age [odds ratio (OR) 4.7; 95% confidence interval (CI) 1.4-15.8 vs. OR 1.3; 95% CI 0.7-2.6]. Similarly, newborns with funisitis who developed neonatal inflammation-initiating illness were at increased risk of VE, unlike those who did not develop such illness, compared to the referent group without either condition [OR 3.6 (95% CI 1.5-8.3) vs. OR 1.7 (95% CI 0.5-5.5)]. The greater the number of these three types of inflammation documented, the higher the risk of VE (P<0.0001).

CONCLUSION

Chronic placental inflammation, acute fetal inflammation, and neonatal inflammation-initiating illness seem to interact in contributing risk information and/or directly damaging the developing brain of newborns delivered very preterm.

The impact of prenatal and neonatal infection on neurodevelopmental outcomes in very preterm infants

OBJECTIVE

Determine the association of prenatal and neonatal infections with neurodevelopmental outcomes in very preterm infants.

STUDY DESIGN

Secondary retrospective analysis of 155 very preterm infants at a single tertiary referral center. General linear or logistic regression models were used to evaluate the association with hospital factors; brain injury, growth and development; and neurobehavioral outcome.

RESULT

Necrotizing enterocolitis with sepsis was associated with reduced transcerebellar diameter (38.3 vs 48.4 mm, P<0.001) and increased left ventricular diameter (12.0 vs 8.0 mm, P=0.005). Sepsis alone was associated with higher diffusivity in the left frontal lobe (1.85 vs 1.68 × 10⁻³ mm² s⁻¹, P=0.001) and right cingulum bundle (1.52 vs 1.45 × 10⁻³ mm 253 s⁻¹, P=0.002). Neurobehavioral outcomes were worse in children exposed to maternal genitourinary infection (cognitive composite: β=-8.8, P=0.001; receptive language score: β=-2.7, P<0.001; language composite: β=-14.9, P<0.001) or histological chorioamnionitis (language composite: β=-8.6, P=0.006), but not neonatal infection.

CONCLUSION

Neonatal infection was associated with changes in brain structure but not with neurobehavioral outcomes, whereas the opposite pattern was observed for maternal genitourinary tract infection. These findings emphasize the potential importance of infections during pregnancy on the neurodevelopmental outcomes of preterm infants.

Complex pattern of interaction between in utero hypoxia-ischemia and intra-amniotic inflammation disrupts brain development and motor function

BACKGROUND

Infants born preterm commonly suffer from a combination of hypoxia-ischemia (HI) and infectious perinatal inflammatory insults that lead to cerebral palsy, cognitive delay, behavioral issues and epilepsy. Using a novel rat model of combined late gestation HI and lipopolysaccharide (LPS)-induced inflammation, we tested our hypothesis that inflammation from HI and LPS differentially affects gliosis, white matter development and motor impairment during the first postnatal month.

METHODS

Pregnant rats underwent laparotomy on embryonic day 18 and transient systemic HI (TSHI) and/or intra-amniotic LPS injection. Shams received laparotomy and anesthesia only. Pups were born at term. Immunohistochemistry with stereological estimates was performed to assess regional glial loads, and western blots were performed for protein expression. Erythropoietin ligand and receptor levels were quantified using quantitative PCR. Digigait analysis detected gait deficits. Statistical analysis was performed with one-way analysis of variance and post-hoc Bonferonni correction.

RESULTS

Microglial and astroglial immunolabeling are elevated in TSHI + LPS fimbria at postnatal day 2 compared to sham (both P < 0.03). At postnatal day 15, myelin basic protein expression is reduced by 31% in TSHI + LPS pups compared to shams (P < 0.05). By postnatal day 28, white matter injury shifts from the acute injury pattern to a chronic injury pattern in TSHI pups only. Both myelin basic protein expression (P < 0.01) and the phosphoneurofilament/neurofilament ratio, a marker of axonal dysfunction, are reduced in postnatal day 28 TSHI pups (P < 0.001). Erythropoietin ligand to receptor ratios differ between brains exposed to TSHI and LPS. Gait analyses reveal that all groups (TSHI, LPS and TSHI + LPS) are ataxic with deficits in stride, paw placement, gait consistency and coordination (all P < 0.001).

CONCLUSIONS

Prenatal TSHI and TSHI + LPS lead to different patterns of injury with respect to myelination, axon integrity and gait deficits. Dual injury leads to acute alterations in glial response and cellular inflammation, while TSHI alone causes more prominent chronic white matter and axonal injury. Both injuries cause significant gait deficits. Further study will contribute to stratification of injury mechanisms in preterm infants, and guide the use of promising therapeutic interventions.

Gene-environment interactions in severe intraventricular hemorrhage of preterm neonates

Intraventricular hemorrhage (IVH) of the preterm neonate is a complex developmental disorder, with contributions from both the environment and the genome. IVH, or hemorrhage into the germinal matrix of the developing brain with secondary periventricular infarction, occurs in that critical period of time before the 32nd to 33rd wk postconception and has been attributed to changes in cerebral blood flow to the immature germinal matrix microvasculature. Emerging data suggest that genes subserving coagulation, inflammatory, and vascular pathways and their interactions with environmental triggers may influence both the incidence and severity of cerebral injury and are the subject of this review. Polymorphisms in the Factor V Leiden gene are associated with the atypical timing of IVH, suggesting an as yet unknown environmental trigger. The methylenetetrahydrofolate reductase (MTHFR) variants render neonates more vulnerable to cerebral injury in the presence of perinatal hypoxia. The present study demonstrates that the MTHFR 677C>T polymorphism and low 5-min Apgar score additively increase the risk of IVH. Finally, review of published preclinical data suggests the stressors of delivery result in hemorrhage in the presence of mutations in collagen 4A1, a major structural protein of the developing cerebral vasculature. Maternal genetics and fetal environment may also play a role.

Inflammation-initiating illnesses, inflammation-related proteins, and cognitive impairment in extremely preterm infants

Neonatal inflammation is associated with perinatal brain damage. We evaluated to what extent elevated blood levels of inflammation-related proteins supplement information about the risk of impaired early cognitive function provided by inflammation-related illnesses. From 800 infants born before the 28th week of gestation, we collected blood spots on days 1, 7 and 14, for analysis of 25 inflammation-related proteins, and data about culture-positive bacteremia, necrotizing enterocolitis (Bell stage IIIb), and isolated perforation of the intestine, during the first two weeks, and whether they were ventilated on postnatal day 14. We considered a protein to be persistently or recurrently elevated if its concentration was in the top quartile (for gestational age and day blood was collected) on two separate days one week apart. We assessed the children at 2 years of age with the Bayley Mental Development Index (MDI). The combinations of NEC and ventilation on day 14, and of bacteremia and ventilation on day 14 consistently provided information about elevated risk of MDI <55, regardless of whether or not a variable for an elevated protein concentration was included in the model. A variable for a persistently or recurrently elevated concentration of each of the following proteins provided additional information about an increased risk of MDI <55: CRP, SAA, IL-6, TNF-alpha, IL-8, MIP-1beta, ICAM-1, E-SEL, and IGFBP-1. We conclude that elevated blood concentrations of inflammation-related proteins provide information about the risk of impaired cognitive function at age 2 years that supplements information provided by inflammation-associated illnesses.