Value of biochemical markers for outcome in term infants with asphyxia

Neonatal asphyxia as an inflammatory disease: Reactive oxygen species and cytokines

Neonatologists resuscitate asphyxiated neonates by every available means, including positive ventilation, oxygen therapy, and drugs. Asphyxiated neonates sometimes present symptoms that mimic those of inflammation, such as fever and edema. The main pathophysiology of the asphyxia is inflammation caused by hypoxic-ischemic reperfusion. At birth or in the perinatal period, neonates may suffer several, hypoxic insults, which can activate inflammatory cells and inflammatory mediator production leading to the release of larger quantities of reactive oxygen species (ROS). This in turn triggers the production of oxygen stress-induced high mobility group box-1 (HMGB-1), an endogenous damage-associated molecular patterns (DAMPs) protein bound to toll-like receptor (TLR) -4, which activates nuclear factor-kappa B (NF-κB), resulting in the production of excess inflammatory mediators. ROS and inflammatory mediators are produced not only in activated inflammatory cells but also in non-immune cells, such as endothelial cells. Hypothermia inhibits pro-inflammatory mediators. A combination therapy of hypothermia and medications, such as erythropoietin and melatonin, is attracting attention now. These medications have both anti-oxidant and anti-inflammatory effects. As the inflammatory response and oxidative stress play a critical role in the pathophysiology of neonatal asphyxia, these drugs may contribute to improving patient outcomes.

Two Useful Umbilical Biomarkers for Therapeutic Hypothermia Decision in Patients with Hypoxic İschemic Encephalopathy with Perinatal Asphyxia: Netrin-1 and Neuron Specific Enolase

Hypoxic-ischemic encephalopathy (HIE) has a high risk of mortality in addition to serious neurological damage. In this study, we investigated the values of umbilical cord netrin-1 (NT-1) and neuron specific enolase (NSE) levels in the early diagnosis of HIE stage II/III induced by neonatal asphyxia. In the study group, infants with gestational age ≥ 36 weeks who were diagnosed with HIE II/III were included. NT-1 and NSE levels were measured from the umbilical cord immediately after birth. Results were compared between HIE II/III and the healthy control group. Cutoff values for serum NT-1 and NSE were determined with receiver-operating characteristics curves and the area under the curve (AUC) was used to determine the diagnostic value of NT-1 and NSE levels in infants diagnosed with HIE II/III. NT-1 (358.3 ± 108.3 pg/mL) and NSE (52.97 ± 17.8 ng/mL) levels in the cord blood in the HIE group were significantly higher (p = .030, p = .001, respectively) than cord blood values in the control group (NT-1 (275.1 ± 84.6 pg/mL) and NSE (28.7 ± 16.3 ng/mL)). NT-1 cutoff value for HIE was 292.3 pg/mL and 34.7 ng/mL for NSE (AUC: 990, sensitivity: 94%, specificity 100% and AUC: 1.0, sensitivity: 100% vs. specificity 100%, respectively). NT-1 and NSE represent candidate biomarkers with high reliability in the prediction in newborns with moderate-to-severe HIE.

Knockdown of interleukin-6 plays a neuroprotective role against hypoxia-ischemia in neonatal rats via inhibition of caspase 3 and Bcl-2-associated X protein signaling pathway

This study aimed to investigate the role of interleukin-6 (IL-6) in the pathogenesis of neonatal hypoxic-ischemic encephalopathy (NHIE). Sprague-Dawley (SD) rats were used for the establishment of hypoxic-ischemic (HI) model. The Zea-Longa scoring was used to evaluate the extent of the neurological deficits. Triphenyl tetrazolium chloride (TTC) staining was used to measure the volume of infarction in the brain following HI protocol. The expression of IL-6 in the cortex and/or hippocampus at multiple time points after HI was examined by immunohistochemistry, western blotting and immunofluorescence. Moreover, small interfering RNAs (siRNA) were used to inhibit the expression of IL-6 in-vitro and in-vivo, and the concomitant expression of the Bcl-2 associated X protein (BAX) and caspase 3 was also measured. HI induced a significant brain damage, and these pathological changes were accompanied by IL-6 upregulation which was found localized in cortical neurons. The inhibition of IL-6 expression fostered neuronal and axonal growth, and a reduction in cellular apoptosis in cortical neuronal cultures, and cortex and hippocampus of neonatal rats. The expression of apoptotic markers such as BAX and caspase 3 was closely associated with IL-6. Downregulation of IL-6 could ameliorate HI-induced deficiencies by mediating the expression of caspase 3 and BAX.

Effect of Hypothermia on Serum Myelin Basic Protein and Tumor Necrosis Factor-α in Neonatal Hypoxic-Ischemic Encephalopathy

OBJECTIVE

Multiple randomized controlled trials have shown that hypothermia is a safe and effective treatment for neonatal moderate or severe hypoxic-ischemic encephalopathy (HIE). The neuroprotective mechanisms of hypothermia need further study. The aim of this study was to investigate the effect of hypothermia on the serum levels of myelin basic protein (MBP) and tumor necrosis factor-α (TNF-α) as well as neurodevelopmental outcomes in neonatal HIE.

STUDY DESIGN

Eighty-five neonates with moderate-to-severe HIE were divided into a hypothermia group (n = 49) and a control group (n = 36). Serum levels of MBP and TNF-α within 6 hours after birth and after 3 days of treatment were determined by enzyme-linked immunosorbent assay, and neurodevelopmental outcome at the age of 12 to 15 months was assessed by using the Gesell development scale.

RESULTS

After 3 days of treatment, serum levels of MBP and TNF-α in the control group were not significantly different from levels before treatment (p > 0.05), and serum levels of MBP and TNF-α in the hypothermia group were significantly lower than levels before treatment (p < 0.05). Serum levels of MBP and TNF-α were significantly negatively correlated with developmental quotient (DQ; r =  - 0.7945, p = 0.0000; r =  - 0.7035, p = 0.0000, respectively). Serum levels of MBP and TNF-α in neurodevelopmentally impaired infants were significantly higher than those in infants with suspected neurodevelopmental impairment and those in neurodevelopmentally normal infants (both p < 0.01). The rate of reduction of neurodevelopmental impairment was higher among infants in the hypothermia group than among those in the control group (χ² = 16.3900, p < 0.05).

CONCLUSION

Hypothermia can reduce serum levels of MBP and TNF-α in neonates with HIE. Inhibiting the release of TNF-α may be one of the mechanisms by which hypothermia protects the myelin sheath.

KEY POINTS

· Hypothermia can reduce serum levels of MBP and TNF-α in neonatal HIE.. · Hypothermia improves neurodevelopmental outcomes and reduces the rate of neurodevelopmental impairment.. · Hypothermia is a feasible and effective treatment for neonates with moderate or severe HIE..

Blood Biomarkers and 6- to 7-Year Childhood Outcomes Following Neonatal Encephalopathy

OBJECTIVE

This study aimed to profile the cytokine/chemokine response from day 0 to 7 in infants (≥36 weeks of gestational age) with neonatal encephalopathy (NE) and to explore the association with long-term outcomes.

STUDY DESIGN

This was a secondary study of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network randomized controlled trial of whole body hypothermia for NE. Eligible infants with moderate-severe NE were randomized to cooling or normothermia. Blood spots were collected on days 0 to 1, 2 to 4, and 6 to 7. Twenty-four cytokines/chemokines were measured using a multiplex platform. Surviving infants underwent neurodevelopmental assessment at 6 to 7 years. Primary outcome was death or moderate-severe impairment defined by any of the following: intelligence quotient <70, moderate-severe cerebral palsy (CP), blindness, hearing impairment, or epilepsy.

RESULTS

Cytokine blood spots were collected from 109 participants. In total 99 of 109 (91%) were assessed at 6 to 7 years; 54 of 99 (55%) developed death/impairment. Neonates who died or were impaired had lower early regulated upon activation normal T cell expressed and secreted (RANTES) and higher day 7 monocyte chemotactic protein (MCP)-1 levels than neonates who survived without impairment. Though TNF-α levels had no association with death/impairment, higher day 0 to 1 levels were observed among neonates who died/developed CP. On multiple regression analysis adjusted for center, treatment group, sex, race, and level of hypoxic ischemic encephalopathy, higher RANTES was inversely associated with death/impairment (odds ratio (OR): 0.31, 95% confidence interval [CI]: 0.13-0.74), while day seven MCP-1 level was directly associated with death/impairment (OR: 3.70, 95% CI: 1.42-9.61). Targeted cytokine/chemokine levels demonstrated little variation with hypothermia treatment.

CONCLUSION

RANTES and MCP-1 levels in the first week of life may provide potential targets for future therapies among neonates with encephalopathy.

KEY POINTS

· Elevation of specific cytokines and chemokines in neonates with encephalopathy has been noted along with increased risk of neurodevelopmental impairment in infancy.. · Cytokine/chemokines at <7 days were assessed among neonates in a trial of hypothermia for HIE.. · Neonates who died or were impaired at 6 to 7 years following hypoxic-ischemic encephalopathy had lower RANTES and higher MCP-1 levels than those who survived without impairment..

Promising candidate cerebrospinal fluid biomarkers of seizure disorder, infection, inflammation, tumor, and traumatic brain injury in pediatric patients

Cerebrospinal fluid (CSF) is a dynamic metabolically active body fluid that has many important roles and is commonly analyzed in pediatric patients, mainly to diagnose central nervous system infection and inflammation disorders. CSF components have been extensively evaluated as biomarkers of neurological disorders in adult patients. Circulating microRNAs in CSF are a promising class of biomarkers for various neurological diseases. Due to the complexity of pediatric neurological disorders and difficulty in acquiring CSF samples from pediatric patients, there are challenges in developing CSF biomarkers of pediatric neurological disorders. This review aimed to provide an overview of novel CSF biomarkers of seizure disorders, infection, inflammation, tumor, traumatic brain injuries, intraventricular hemorrhage, and congenital hydrocephalus exclusively observed in pediatric patients.

Value of brain damage biomarkers in cerebrospinal fluid in neonates with hypoxic-ischemic brain injury

Hypoxic-ischemic encephalopathy is one of the leading causes of death and neurological disability worldwide. A key issue in neonates with hypoxic-ischemic encephalopathy is accurately establishing the occurrence and severity of brain lesions soon after a perinatal hypoxic-ischemic event. This is crucial to help with prognosis; guide clinical decision-making, including the use of other therapies; and improve family counseling. Neurobiochemical markers may offer a quantitative approximation for estimating the severity of brain damage and identifying infants who have a high risk of further neurological disability. In addition, they should help identify those neonates who would benefit most from the implementation of other neuroprotective and neuroreparative interventions. Despite considerable progress in this area, relatively few studies have been aimed at examining the clinical utility of brain-specific proteins in cerebrospinal fluid, an important opening to characterizing pathological phenomena associated with hypoxic-ischemic brain injury.

The Urinary Uric Acid / Cr ratio as a marker of morbidity and mortality of preterm infants: a case-control study

BACKGROUND

Perinatal asphyxia is one of the main causes of preterm infant mortality. Some studies have shown that The Urinary Uric Acid / Cr (UUA/Cr) ratio may be used as an additional marker for perinatal asphyxia.This study intend to investigate the relationship of this ratio with outcomes of preterm infants admitted to NICU.

METHODS

This case-control study was carried on 102 preterm newborn infants with gestational age of 30 weeks to 33 weeks and 6 days admitted in the neonatal intensive care unit.The case group, consisted of 51 premature neonates with a history of intubation, cardiopulmonary resuscitation, mechanical ventilation and Nasal continuous positive airway pressure (NCPAP) at birth, were compared with 51 matched neonates. The UUA/Cr ratio was measured in the first 24 h after birth. Complications during hospitalization, duration of hospitalization, and final outcome were evaluated.

RESULTS

The mean level of UUA/Cr ratio in case and control group were 5.4 ± 4.1 and 3.6 9 ± 2.9 respectively and this difference was statistically significant (p = 0.014). The UUA/Cr ratio were significantly higher in females, cesarean section delivery, Apgar score ≥ 8, neonates without any complication and neonates with less than 10 days of hospitalization. However, this ratio has no predictive value for the incidence of complications during hospitalization and long-term hospital stay for infants of the case group.

CONCLUSIONS

The Urinary Uric Acid / Cr ratio in the first 24 h after birth in preterm neonates who underwent intubation, NCPAP or cardiopulmonary resuscitation was higher than healthy neonates.

Can we delineate brain injury in full-term neonates using serum biomarkers?

OBJECTIVE: Early identification of neonates at risk of neurological impairment is particularly important for the bedside clinician. Clinical value of S100b and neuron-specific enolase in neonates has not been yet established. We investigated their kinetics and possible early clinical utility in neonatal encephalopathy (NE).STUDY DESIGN: 36 full-term neonates (13 with moderate/severe encephalopathy, 11 with mild encephalopathy, 12 controls) were enrolled and studied prospectively. Serum S100b and neuron-specific enolase (NSE) were measured serially on days(d) 1, 3, 9 and 18 of life. Brain MRI and long-term neurodevelopmental outcome were also assessed.RESULT: Neonates with moderate/severe encephalopathy had significantly increased S100b (d1) and NSE levels (d1, d3, d9) compared to controls. Neuron-specific enolase significantly correlated with the degree of encephalopathy, and a cutoff of 38.8 μg/l (d1) accurately predicted moderate/severe encephalopathy. S100b (d1) cutoff points of 1.6 μg/l and 11.4 μg/l prognosticated severe encephalopathy and death/cerebral palsy, respectively. Both biomarkers correlated well with neuroimaging and Bayley-III scores.CONCLUSION: Combined clinical, laboratory, imaging and neurodevelopmental data indicate that serum S100b and NSE can be useful biomarkers for the diagnosis and prognosis of neonatal brain injury, providing useful information to the bedside clinician.

Predictive value of biochemical and hematological markers in prognosis of asphyxic infants

Background:

Asphyxia is one of the main causes of infant mortality and long-term neurologic complications. This cohort study was aimed to compare the diagnostic value of the hematologic and biochemical factors in the prediction of prognosis of asphyxia according to the high prevalence of asphyxia and its complications.

Methods:

In this cohort with a two-year follow-up study with availability sampling, 196 term asphyxic infants were involved from 2009 to 2018. A researcher-designed questionnaire was used as the data collection tool containing infantile and maternal particulars as well as the clinical and laboratory assessments. Serum levels of interleukin-1β(IL-1β), IL-6, pro-oxidant/antioxidant balance (PAB), heat shock protein (HSP) and nucleated red blood cells (NRBC) were checked in infants with perinatal asphyxia. Denver II developmental screening test (DDST-II) was performed at 6, 12, 18, and 24 month post-discharge follow-up visits. Data analysis for comparison of infants with normal and abnormal outcomes was performed using student t- test, chi-square, ROC curve, and regression models.

Results:

IL-6, IL-1β, PAB, and NRBC count are among the most important predictors of abnormal complications in asphyxic newborns. PAB>22 (HK) showed sensitivity and specificity of 88.6% and 71.6%, respectively in the prediction of complications of asphyxia. The sensitivity and specificity of an IL-6 higher than 28 (pg/mL) in the prediction of complications of asphyxia were found to be 96.1% and 78.6%, respectively. Elevated levels of IL-6 and IL-1β were associated with increased unfavorable outcomes.

Conclusion:

Combinations of: IL-1β+ IL-6 + NRBC; IL-6 + HIE grade + PAB; and IL-6+ HIE grade + NRBC had the highest predictive value (100%) for prognosis of asphyxic infants.

Cerebrospinal fluid levels of neuron-specific enolase predict the severity of brain damage in newborns with neonatal hypoxic-ischemic encephalopathy treated with hypothermia

Objectives

To investigate whether cerebrospinal fluid levels of neuron-specific enolase (CSF-NSE) during the first 72 hours correlate with other tools used to assess ongoing brain damage, including clinical grading of hypoxic-ischemic encephalopathy (HIE), abnormal patterns in amplitude integrated electroencephalography (aEEG), and magnetic resonance imaging (MRI), as well as with the neurodevelopmental outcomes at two years of age.

Material and methods

Prospective observational study performed in two hospitals between 2009 and 2011. Forty-three infants diagnosed with HIE within 6 hours of life were included. HIE was severe in 20 infants, moderate in 12, and mild in 11. Infants with moderate-to-severe HIE received whole-body cooling. Both the HIE cohort and a control group of 59 infants with suspected infection underwent measurement of CSF-NSE concentrations at between 12 and 72 hours after birth. aEEG monitoring was started at admission and brain MRI was performed within the first 2 weeks. Neurodevelopment was assessed at 24 months.

Results

The HIE group showed higher levels of CSF-NSE than the control group: median 70 ng/ml (29; 205) vs 10.6 ng/ml (7.7; 12.9); p <0.001. Median levels of CSF-NSE in infants with severe, moderate, and mild HIE were 220.5 ng/ml (120.5; 368.8), 45.5 ng/ml (26, 75.3), and 26 ng/ml (18, 33), respectively. CSF-NSE levels correlated were significantly higher in infants with seizures, abnormal aEEG, or abnormal MRI, compared to those without abnormalities. Infants with an adverse outcome showed higher CSF-NSE levels than those with normal findings (p<0.001), and the most accurate CSF-NSE cutoff level for predicting adverse outcome in the whole cohort was 108 ng/ml and 50ng/ml in surviving infants.

Conclusions

In the era of hypothermia, CSF-NSE concentrations provides valuable information as a clinical surrogate of the severity of hypoxic-ischemic brain damage, and this information may be predictive of abnormal outcome at two years of age.

Neuron-Specific Enolase in Cerebrospinal Fluid Predicts Brain Injury After Sudden Unexpected Postnatal Collapse

BACKGROUND

Biomarkers of brain injury with high predictive value in newborns in critical neurological status are increasingly required. Neuron-specific enolase in cerebrospinal fluid has been shown to be highly predictive in newborns with perinatal hypoxic-ischemic encephalopathy, but its utility has not been examined in sudden unexpected postnatal collapse.

PURPOSE

We analyzed whether the levels of neuron-specific enolase in cerebrospinal fluid can be a useful biomarker to estimate the severity of brain injury in neonates after a sudden unexpected postnatal collapse.

METHODS

This is a prospective observational study of near-term infants who were consecutively admitted with sudden unexpected postnatal collapse in two neonatal intensive care units during a nine-year period. Variables were collected and analyzed regarding the perinatal period, clinical course, severity of encephalopathy, amplitude-integrated encephalography, magnetic resonance imaging findings, and outcome. Neuron-specific enolase in cerebrospinal fluid samples were obtained in 18 infants with sudden unexpected postnatal collapse between 12 and 72 hours after the collapse and compared with those of 29 controls.

RESULTS

The levels of neuron-specific enolase in cerebrospinal fluid were higher in patients than in controls (P < 0.001). Levels of neuron-specific enolase in cerebrospinal fluid in infants with sudden unexpected postnatal collapse were significantly higher in patients who presented severe encephalopathy, seizures, abnormal amplitude-integrated encephalography background, or brain injury on magnetic resonance imaging. Receiver operator characteristic curve analysis revealed a neuron-specific enolase in cerebrospinal fluid cutoff value of maximum predictive accuracy of 61 ng/mL (area under the curve, 1.0; sensitivity, specificity, positive predictive value, and negative predictive value, 100%) for identifying infants who died or had adverse outcomes.

CONCLUSIONS

Levels of neuron-specific enolase in cerebrospinal fluid obtained between 12 and 72 hours after a sudden unexpected postnatal collapse event seem to be a useful biomarker for identifying newborns with severe brain injury and for predicting outcome.

Fas-ligand and interleukin-6 in the cerebrospinal fluid are early predictors of hypoxic-ischemic encephalopathy and long-term outcomes after birth asphyxia in term infants

BACKGROUND

Cerebral ischemia generates neuroinflammation that can induce neural cell death. This cohort study assessed whether Fas-ligand (FasL) and interleukin (IL)-6 levels in the cerebrospinal fluid (CSF) after hypoxic-ischemic encephalopathy (HIE) can serve as biomarkers of hypoxic brain injury in neonates.

METHODS

Term infants (> 37-week gestational age) who were admitted to the neonatal intensive care unit of Karolinska University Hospital in years 2002 to 2004 with perinatal asphyxia were enrolled prospectively. Control infants without brain pathology underwent lumbar puncture for suspected infection. FasL and IL-6 levels were measured in the CSF, by enzyme-linked immunosorbent assays. All patients underwent neurological assessment at 18 months. HIE was classified as mild, moderate, or severe (HIE I-III). Adverse neurological outcome at 18 months was defined as a mental developmental index < 85, deafness, blindness, cerebral palsy, or seizure disorder.

RESULTS

Of the 44 HIE patients, 14, 16, and 14 had HIE-I, HIE-II, and HIE-III, respectively. HIE-II and HIE-III patients had higher FasL and IL-6 levels than HIE-I patients and the 20 controls (all p < 0.0001). Patients with adverse outcomes had higher FasL and IL-6 levels than patients with normal outcomes and controls (both p < 0.0001). On receiver-operator curve analyses, FasL and IL-6 (alone and together) were highly predictive of HIE grade and outcome (areas under the curve range 0.86-0.94) and showed high sensitivity (66.7-100%). These biomarkers performed better than cord blood pH (areas under the curve: HIE grade = 0.80, adverse outcomes = 0.86).

CONCLUSION

CSF biomarkers FasL and IL-6 predicted severity of encephalopathy and long-term outcomes in post-asphyxiated infants better than a standard biomarker.

Interleukins in diagnosis of perinatal asphyxia: A systematic review

Background

Biochemical markers including interleukins (ILs) has been proposed for early diagnosis of asphyxia.

Objective

This study has aimed to systematically review the significance of IL measurements in the diagnosis of perinatal asphyxia.

Materials and Methods

PubMed, Cochrane Library, Web of Science, Embase, and Scopus databases before 2017 were searched for the following keywords: asphyxia, neonatal, interleukin, and diagnosis. A total of 13 out of 300 searched papers were finally selected for evaluation. Interleukins under study were IL6 and interleukin 1 β (IL-1 β ). Interleukins had been measured in 10 studies by serum samples, 2 studies by samples of Cerebro Spinal Fluid (CSF), and 1 study by sample of umbilical cord blood. The inclusion criteria were: studies on neonates, with adequate information from the test results and studies using markers other than ILs to detect asphyxia; however, studies with only abstracts available were excluded.

Results

Research on the issue suggests that IL6 > 41 Pg/dl has the sensitivity of 84.88% and the specificity of 85.43%, whereas IL-1 β > 4.7 Pg/dl has the sensitivity of 78% and specificity of 83% in the diagnosis of neonatal asphyxia. Among diagnostic ILs for neonatal asphyxia, combination of IL6 and IL-1 β had the highest sensitivity, that is, 92.9%.

Conclusion

IL6 and IL-1 β of serum samples were used in the early diagnosis of perinatal asphyxia and are useful predictors for the outcomes of perinatal asphyxia and its intensity. In addition, simultaneous evaluation of IL-1 β and IL6 can improve the sensitivity of the early diagnosis of perinatal asphyxia.

Random urine uric acid to creatinine and prediction of perinatal asphyxia: a meta-analysis

Objective: The purpose of the present review is to evaluate whether urine uric acid to creatinine ratio is increased in perinatal asphyxia and hypoxic-ischemic encephalopathy (HIE), as well as to assess its predictive accuracy in the disease. Methods: We used the Medline (1966-2017), Scopus (2004-2017), Clinicaltrials.gov (2008-2017), Embase (1980-2017), Cochrane Central Register of Controlled Trials CENTRAL (1999-2017), and Google Scholar (2004-2017) databases in our primary search along with the reference lists of electronically retrieved full-text papers. The hierarchical summary receiver operating characteristic (HSROC) model was used for the meta-analysis of diagnostic accuracy. Results: Fourteen studies were finally included in the present review, that investigated 1226 neonates. Urinary uric acid to creatinine ratio was significantly higher in neonates with perinatal asphyxia than in healthy controls (mean differences (MD): 1.43 95%CI [1.17, 1.69]). Specifically, the mean difference for Sarnat stage 1 was 0.70 (95%CI [0.28, 1.13]), for stage 2 1.41 (95%CI [0.99, 1.84]), and for stage 3 2.71 (95%CI [2.08, 3.35]). The estimated sensitivity for the summary point was 0.90 (95%CI (0.82-0.95)), the specificity was 0.88 (95%CI (0.73-0.95)) and the diagnostic odds ratio was calculated at 63.62 (95%CI (17.08-236.96)). Conclusions: Urinary uric acid to creatinine ratio is a rapid and an easily detected biomarker that may help physicians identify neonates at risk of developing perinatal asphyxia and HIE. However, large-scale prospective studies are still needed to determine its value in predicting mortality, as well as short- and long-term adverse neurological outcomes.

Mild hypoxic ischaemic encephalopathy and long term neurodevelopmental outcome - A systematic review

AIMS

Hypoxic ischaemic encephalopathy (HIE) remains a significant cause of long term neurodisability despite therapeutic hypothermia (TH). Infants with mild HIE, representing 50% of those with HIE, are perceived as low risk and are currently not eligible for TH [1]. This review examines the available evidence of outcome in term infants with mild HIE.

METHODS

Medline, Embase and Cochrane Clinical Trials databases were searched in March 2017. Studies with well-defined HIE grading at birth and standardised neurodevelopmental assessment at ≥18 months were included. Abnormal outcome was defined as death, cerebral palsy or standardised neurodevelopmental test score more than 1 standard deviation below the mean.

RESULT

Twenty studies were included. Abnormal outcome was reported in 86/341 (25%) of infants. There was insufficient evidence to examine the effect of TH on outcome.

CONCLUSION

A significant proportion of infants with mild HIE have abnormal outcome at follow up.

Association between serum interleukin-6 levels and severity of perinatal asphyxia

Background: Perinatal asphyxia is a major cause of neurologic morbidity and mortality in infants. Objective: Determine the serum level of interleukin-6 (IL-6) in neonates with perinatal asphyxia and its relation to the severity of hypoxic-ischemic encephalopathy and short term neurological outcome. Methods: Serum IL-6 levels were measured at birth, and at 24 and 48 hour post-partum in 37 consecutive uninfected neonates with peri-natal asphyxia and 45 randomly selected healthy newborns. Results: Serum IL-6 concentrations in the infants who developed hypoxic-ischemic encephalopathy was 43 folds higher compared to values in the normal infants (p < 0.001) and 1.9 folds higher as compared to infants with asphyxia who did not subsequently develop hypoxic-ischemic encephalopathy (p <0.001). Serum IL-6 concentrations were also related to the degree of hypoxic-ischemic encephalopathy and neurologicaldevelopmental outcomes at the time of discharge. Conclusion: Serum levels of IL-6 increased in neonates with asphyxia, and this was most pronounced in neonates with adverse outcomes.

Plasma Biomarkers of Brain Injury in Neonatal Hypoxic-Ischemic Encephalopathy

OBJECTIVES

To evaluate plasma brain specific proteins and cytokines as biomarkers of brain injury in newborns with hypoxic-ischemic encephalopathy (HIE) and, secondarily, to assess the effect of erythropoietin (Epo) treatment on the relationship between biomarkers and outcomes.

STUDY DESIGN

A study of candidate brain injury biomarkers was conducted in the context of a phase II multicenter randomized trial evaluating Epo for neuroprotection in HIE. Plasma was collected at baseline (<24 hours) and on day 5. Brain injury was assessed by magnetic resonance imaging (MRI) and neurodevelopmental assessments at 1 year. The relationships between Epo, brain-specific proteins (S100B, ubiquitin carboxy-terminal hydrolase-L1 [UCH-L1], total Tau, neuron specific enolase), cytokines (interleukin [IL]-1β, IL-6, IL-8, IL-10, IL-12P70, IL-13, interferon-gamma [IFN-γ], tumor necrosis factor alpha [TNF-α], brain-derived neurotrophic factor [BDNF], monocyte chemoattractant protein-1), and brain injury were assessed.

RESULTS

In 50 newborns with encephalopathy, elevated baseline S100B, Tau, UCH-L1, IL-1β, IL-6, IL-8, IL-10, IL-13, TNF-α, and IFN-γ levels were associated with increasing brain injury severity by MRI. Higher baseline Tau and lower day 5 BDNF were associated with worse 1 year outcomes. No statistically significant evidence of Epo treatment modification on biomarkers was detected in this small cohort.

CONCLUSIONS

Elevated plasma brain-specific proteins and cytokine levels in the first 24 hours of life are associated with worse brain injury by MRI in newborns with HIE. Only Tau and BDNF levels were found to be related to neurodevelopmental outcomes. The effect of Epo treatment on the relationships between biomarkers and brain injury in HIE requires further study.

TRIAL REGISTRATION

ClinicalTrials.gov: 01913340.

Inflammatory cytokine response and reduced heart rate variability in newborns with hypoxic-ischemic encephalopathy

OBJECTIVE

To determine whether systemic inflammation-modulating cytokine expression is related to heart rate variability (HRV) in newborns with hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

The data from 30 newborns with HIE were analyzed. Cytokine levels (IL-2, IL-4, IL-6, IL-8, IL-10, IL-13, IL-1β, TNF-α, IFN-λ) were measured either at 24 h of cooling (n=5), 72 h of cooling (n=4) or at both timepoints (n=21). The following HRV metrics were quantified in the time domain: alpha_S, alpha_L, root mean square (RMS) at short time scales (RMS_S), RMS at long time scales (RMS_L), while low-frequency power (LF) and high-frequency power (HF) were quantified in the frequency domain. The relationships between HRV metrics and cytokines were evaluated using mixed-models.

RESULT

IL-6, IL-8, IL-10, and IL-13 levels were inversely related to selected HRV metrics.

CONCLUSION

Inflammation-modulating cytokines may be important mediators in the autonomic dysfunction observed in newborns with HIE.

Urinary Uric Acid/Creatinine Ratio - A Marker For Perinatal Asphyxia

BACKGROUND

Perinatal hypoxia is one of the leading causes of perinatal mortality in developing countries. Both apgar score and arterial blood pH predict the neonatal mortality in asphyxia. Apgar score alone does not predict neurologic outcome and as it is influenced by various factors. This study was conducted to evaluate the utility and sensitivity of urinary uric acid to creatinine ratio (UA/Cr ratio) in asphyxia diagnosis, compared to invasive Arterial Blood Gas (ABG) analysis.

AIM

To assess the urinary uric acid/creatinine ratio as an additional marker for perinatal asphyxia compared with ABG analysis in apgar score monitoring.

MATERIALS AND METHODS

The present case control study was conducted at a teaching hospital in Central Gujarat. Data of 40 healthy newborns and 40 asphyxiated newborns were collected. In absence of regional estimates, a sample of size 39 was required to attain a power of 80% at 5% alpha (type I error) considering a moderate effect size of 0.65. (UA/Cr) ratio was measured from the spot urine sample collected during 24-72 hours of birth. Statistical analysis was performed by Independent t-test, Pearson's correlation coefficient (r) and Receiver Operating Characteristic (ROC) plots.

RESULTS

The mean (UA/Cr ratio) (2.75±0.18 vs 1.78±0.23) is significantly higher in asphyxiated group than in the control group (p<0.0001). Urinary UA/Cr ratio had negative correlation with blood pH (r= -0.27, p=0.18), which was not significant (p>0.05). Urinary UA/Cr ratio with criterion of >2.3 had 100% sensitivity, 100% specificity with AUC of 1 (p<0.0001) had a better predictive value.

CONCLUSIONS

Apgar score is usually reduced in neonates with congenital anomalies and premature neonates. Hence, it is preferable that the clinical diagnosis of asphyxia by apgar scores be supported by other investigations so that early decision can be taken about the level of care the baby needs. pH, lactates and base deficits change with establishment of respiration following resuscitation. However, pH, lactate, base deficit estimations are invasive and need rapid estimations. Non-invasive urinary UA/Cr ratio may be an answer to these issues as it easy, economical and equally efficient.

Cytokine changes in newborns with therapeutic hypothermia after hypoxic ischemic encephalopathy

OBJECTIVE

This study aimed to examine changes in cytokines according to therapeutic hypothermia (TH) for newborn hypoxic ischemic encephalopathy (HIE).

STUDY DESIGN

We studied 20 neonates who were admitted with a diagnosis of HIE in the neonatal intensive care unit. Cytokine concentration assay was carried out for neonates (n=12) who received TH and neonates (n=8) who were not treated with hypothermia by collecting blood sample at 12, 48 and 120 h after birth.

RESULTS

At 48 h after birth, interleukin (IL)-6 in the normothermia group was higher than that in the hypothermia group (P=0.010). At 48 h after birth, IL-10 was higher in the hypothermia group than in the normothermia group (P=0.038).

CONCLUSION

This study confirmed that TH performs a role in the prevention of inflammatory process by way of maintaining proinflammatory cytokine IL-6 at low levels and anti-inflammatory cytokines IL-10 at high levels.

Association of brain injury and neonatal cytokine response during therapeutic hypothermia in newborns with hypoxic-ischemic encephalopathy

BACKGROUND

Cytokines have been proposed as mediators of neonatal brain injury via neuroinflammatory pathways triggered by hypoxia-ischemia. Limited data are available on cytokine profiles in larger cohorts of newborns with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH).

METHODS

Serum cytokines interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-13, tumor necrosis factor-α, and interferon-γ were measured in newborns with HIE at 24 and 72 h of TH. Differences between infants with favorable (survivors with mild/no magnetic resonance imaging (MRI) injury) vs. adverse outcome (death or moderate/severe MRI injury) were compared using mixed models to adjust for covariates.

RESULTS

Data from 36 term newborns with HIE (favorable outcome: n = 20, adverse outcome: n = 16) were evaluated. Cytokines IL-1β, IL-2, IL-6, IL-8, IL-10, and IL-13 were elevated in the adverse relative to favorable outcome group at 24 h. IL-6 remained significantly elevated in the adverse outcome group at 72 h. IL-6 and IL-10 remained significantly associated with outcome group after controlling for covariates.

CONCLUSION

Inflammatory cytokines are elevated in HIE newborns with brain injury by MRI. In particular, IL-6 and IL-10 were associated with adverse outcomes after controlling for baseline characteristics and severity of presentation. These data suggest that cytokine response may identify infants in need of additional neuroprotective interventions.

Expression of hypoxia-inducible factor 1 alpha and oligodendrocyte lineage gene-1 in cultured brain slices after oxygen-glucose deprivation

Oligodendrocyte lineage gene-1 expressed in oligodendrocytes may trigger the repair of neuronal myelin impairment, and play a crucial role in myelin repair. Hypoxia-inducible factor 1α, a transcription factor, is of great significance in premature infants with hypoxic-ischemic brain damage. There is little evidence of direct regulatory effects of hypoxia-inducible factor 1α on oligodendrocyte lineage gene-1. In this study, brain slices of Sprague-Dawley rats were cultured and subjected to oxygen-glucose deprivation. Then, slices were transfected with hypoxia-inducible factor 1α or oligodendrocyte lineage gene-1. The expression levels of hypoxia-inducible factor 1α and oligodendrocyte lineage gene-1 were significantly up-regulated in rat brains prior to transfection, as detected by immunohistochemical staining. Eight hours after transfection of slices with hypoxia-inducible factor 1α, oligodendrocyte lineage gene-1 expression was upregulated, and reached a peak 24 hours after transfection. Oligodendrocyte lineage gene-1 transfection induced no significant differences in hypoxia-inducible factor 1α levels in rat brain tissues with oxygen-glucose deprivation. These experimental findings indicate that hypoxia-inducible factor 1α can regulate oligodendrocyte lineage gene-1 expression in hypoxic brain tissue, thus repairing the neural impairment.

Serum biomarkers of brain injury to classify outcome after pediatric cardiac arrest*

OBJECTIVES

Morbidity and mortality in children with cardiac arrest largely result from neurologic injury. Serum biomarkers of brain injury can potentially measure injury to neurons (neuron-specific enolase), astrocytes (S100b), and axons (myelin basic protein). We hypothesized that serum biomarkers can be used to classify outcome from pediatric cardiac arrest.

DESIGN

Prospective observational study.

SETTING

Single tertiary pediatric hospital.

PATIENTS

Forty-three children with cardiac arrest.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We measured serum neuron-specific enolase, S100b, and myelin basic protein on days 1-4 and 7 after cardiac arrest. We recorded demographics, details of the cardiac arrest and resuscitation, and Pediatric Cerebral Performance Category at hospital discharge and 6 months. We analyzed the association of biomarker levels at 24, 48, and 72 hours with favorable (Pediatric Cerebral Performance Category 1-3) or unfavorable (Pediatric Cerebral Performance Category 4-6) outcome and mortality. Forty-three children (49% female; mean age of 5.9 ± 6.3) were enrolled and 17 (40%) died. Serum S100b concentrations peaked earliest, followed by neuron-specific enolase and finally myelin basic protein. Serum neuron-specific enolase and S100b concentrations were increased in the unfavorable versus favorable outcome group and in subjects who died at all time points (all p < 0.05). Serum myelin basic protein at 24 and 72 hours correctly classified survival but not good versus poor outcome. Using best specificity, serum S100b and neuron-specific enolase had optimal positive and negative predictive values at 24 hours to classify both favorable versus unfavorable outcome and survival, whereas serum myelin basic protein's best accuracy occurred at 48 hours. Receiver operator curves for serum S100b and neuron-specific enolase to classify favorable versus unfavorable outcome at 6 months were superior to clinical variables.

CONCLUSIONS

Preliminary data show that serum S100b, neuron-specific enolase, and myelin basic protein may aid in outcome classification of children surviving cardiac arrest.

Clinical neuropathology practice guide 5-2013: markers of neuronal maturation

This review surveys immunocytochemical and histochemical markers of neuronal lineage for application to tissue sections of fetal and neonatal brain. They determine maturation of individual nerve cells as the tissue progresses to mature architecture. From a developmental perspective, neuronal markers are all about timing. These diverse cellular labels may be classified in two ways: 1) time of onset of expression (early; intermediate; late); 2) labeling of subcellular structures or metabolic functions (nucleoproteins; synaptic vesicle proteins; enolases; cytoskeletal elements; calcium-binding; nucleic acids; mitochondria). Apart from these positive markers of maturation, other negative markers are expressed in primitive neuroepithelial cells and early stages of neuroblast maturation, but no longer are demonstrated after initial stages of maturation. These examinations are relevant for studies of normal neuroembryology at the cellular level. In fetal and perinatal neuropathology they provide control criteria for application to malformations of the brain, inborn metabolic disorders and acquired fetal insults in which neuroblastic maturation may be altered. Disorders, in which cells differentiate abnormally, as in tuberous sclerosis and hemimegalencephaly, pose another yet aspect of mixed cellular lineage. The measurement in living patients, especially neonates, of serum and CSF levels of enolases, chromogranins and S-100 proteins as biomarkers of brain damage may potentially be correlated with their corresponding tissue markers at autopsy in infants who do not survive. The neuropathological markers here described can be performed in ordinary hospital laboratories, not just research facilities, and offer another dimension of diagnostic precision in interpreting abnormally developed fetal and postnatal brains.

Cord blood proteins and multichannel-electroencephalography in hypoxic-ischemic encephalopathy

OBJECTIVE

To explore the association between multiple umbilical cord blood proteins and severity of hypoxic-ischemic encephalopathy as defined by continuous multichannel electroencephalography.

DESIGN

A prospective case-control cohort study, which was divided into separate exploratory and validation cohorts.

SETTING

A single tertiary neonatal intensive care facility.

PATIENTS

The study recruited full-term infants with perinatal asphyxia and controls. Identical procedures were used to recruit a representative exploratory sample (n = 30) and a subsequent validation cohort (n = 100).

INTERVENTION

All had umbilical cord blood drawn and biobanked at delivery, continuous multichannel electroencephalography commenced in the first 24 hours, and a modified Sarnat score assigned. Analysis of 37 potential cord blood protein markers of hypoxic-ischemic encephalopathy was performed using Luminex multiplex assays.

MEASUREMENTS AND RESULTS

Cord blood from 130 infants was analyzed. Interleukin-16 and interleukin-6 significantly differentiated between a moderate-severely abnormal and normal-mildly abnormal electroencephalography background in both exploratory (p = 0.005 and p = 0.016, respectively) and validation cohorts (p = 0.039 and p = 0.024, respectively). To develop a predictive model for a moderate-severely abnormal electroencephalography, stepwise regression analysis was used to combine these analytes with current standard clinical markers of asphyxia (pH, base deficit, and 10-min Apgar). Only Apgar score and interleukin-16 remained in the model, which was highly predictive of an abnormal electroencephalography (area under the curve [AUC] = 0.956, p < 0.001, positive predictive value = 89%, and negative predictive value = 94%).

CONCLUSIONS

Cord blood interleukin-6 and interleukin-16 were associated with electrographic grade of hypoxic-ischemic encephalopathy. To predict an abnormal electroencephalography, interleukin-16 and 10-minute Apgar used in combination performed better than current markers.

Serum biomarkers of MRI brain injury in neonatal hypoxic ischemic encephalopathy treated with whole-body hypothermia: a pilot study

OBJECTIVES

To determine if candidate biomarkers, ubiquitin carboxyl-terminal esterase L1 and glial fibrillary acidic protein, are elevated in neonates with hypoxic ischemic encephalopathy who die or have severe MRI injury compared with surviving infants with minimal or no injury on brain MRI.

DESIGN

Prospective observational study.

SETTING

Level IIIC outborn neonatal ICU in a free-standing children's hospital.

PATIENTS

Term newborns with moderate-to-severe hypoxic ischemic encephalopathy referred for therapeutic hypothermia

INTERVENTIONS

Serum specimens were collected at 0, 12, 24, and 72 hours of cooling. MRI was performed in surviving infants at target 7-10 days of life and was scored by a pediatric neuroradiologist masked to biomarker and clinical data.

MEASUREMENTS AND MAIN RESULTS

Serial biomarker levels were determined in 20 hypoxic ischemic encephalopathy patients. Ubiquitin carboxyl-terminal esterase L1 was higher at initiation and 72 hours of cooling, while glial fibrillary acidic protein was higher at 24 and 72 hours in babies with adverse outcome compared with those with favorable outcome.

CONCLUSIONS

This preliminary data support further studies to evaluate ubiquitin carboxyl-terminal esterase L1 and glial fibrillary acidic protein as immediate biomarkers of cerebral injury severity in newborns with hypoxic ischemic encephalopathy.

Association of nucleated red blood cells and severity of encephalopathy in normothermic and hypothermic infants

AIM

To determine whether hypothermia alters the discriminative ability of postnatal nucleated red blood cells (NRBCs) to distinguish between mild and moderate/severely encephalopathic infants.

METHODS

A prospective cohort study recruited full-term neonates with hypoxic ischaemic encephalopathy (HIE) from 2003 to 2012 (prehypothermic and hypothermic eras). The NRBC count was analysed in the first 24 h in all infants and compared between normothermic and hypothermic cohorts. The severity of encephalopathy was categorized using both clinical Sarnat score and continuous multichannel EEG.

RESULTS

Eighty-six infants with HIE were included: in the normothermic group, 19 were clinically mild, 24 moderate/severe; in the hypothermic group, 22 were mild, 21 moderate/severe encephalopathy. NRBC count discriminated between mild and moderate/severe Sarnat scores in the normothermic group (p = 0.03) but not in the hypothermic group (p = 0.9). This change was due to a decrease in NRBCs among moderately encephalopathic infants in the hypothermic cohort.

CONCLUSION

Postnatal NRBCs distinguished between mild and moderate/severe encephalopathy in normothermic infants but not in infants undergoing therapeutic hypothermia. We advise caution when using postnatal blood samples to study diagnostic biomarkers for HIE without first analysing the potential impact of hypothermia upon these markers.

The metabolomic profile of umbilical cord blood in neonatal hypoxic ischaemic encephalopathy

Background

Hypoxic ischaemic encephalopathy (HIE) in newborns can cause significant long-term neurological disability. The insult is a complex injury characterised by energy failure and disruption of cellular homeostasis, leading to mitochondrial damage. The importance of individual metabolic pathways, and their interaction in the disease process is not fully understood. The aim of this study was to describe and quantify the metabolomic profile of umbilical cord blood samples in a carefully defined population of full-term infants with HIE.

Methods and Findings

The injury severity was defined using both the modified Sarnat score and continuous multichannel electroencephalogram. Using these classification systems, our population was divided into those with confirmed HIE (n = 31), asphyxiated infants without encephalopathy (n = 40) and matched controls (n = 71). All had umbilical cord blood drawn and biobanked at −80°C within 3 hours of delivery. A combined direct injection and LC-MS/MS assay (AbsolutIDQ p180 kit, Biocrates Life Sciences AG, Innsbruck, Austria) was used for the metabolomic analyses of the samples. Targeted metabolomic analysis showed a significant alteration between study groups in 29 metabolites from 3 distinct classes (Amino Acids, Acylcarnitines, and Glycerophospholipids). 9 of these metabolites were only significantly altered between neonates with Hypoxic ischaemic encephalopathy and matched controls, while 14 were significantly altered in both study groups. Multivariate Discriminant Analysis models developed showed clear multifactorial metabolite associations with both asphyxia and HIE. A logistic regression model using 5 metabolites clearly delineates severity of asphyxia and classifies HIE infants with AUC = 0.92. These data describe wide-spread disruption to not only energy pathways, but also nitrogen and lipid metabolism in both asphyxia and HIE.

Conclusion

This study shows that a multi-platform targeted approach to metabolomic analyses using accurately phenotyped and meticulously biobanked samples provides insight into the pathogenesis of perinatal asphyxia. It highlights the potential for metabolomic technology to develop a diagnostic test for HIE.

Serum cytokines in a clinical trial of hypothermia for neonatal hypoxic-ischemic encephalopathy

Inflammatory cytokines may mediate hypoxic-ischemic (HI) injury and offer insights into the severity of injury and the timing of recovery. In our randomized, multicenter trial of hypothermia, we analyzed the temporal relationship of serum cytokine levels in neonates with hypoxic-ischemic encephalopathy (HIE) with neurodevelopmental outcome at 12 months. Serum cytokines were measured every 12 hours for 4 days in 28 hypothermic (H) and 22 normothermic (N) neonates with HIE. Monocyte chemotactic protein-1 (MCP-1) and interleukins (IL)-6, IL-8, and IL-10 were significantly higher in the H group. Elevated IL-6 and MCP-1 within 9 hours after birth and low macrophage inflammatory protein 1a (MIP-1a) at 60 to 70 hours of age were associated with death or severely abnormal neurodevelopment at 12 months of age. However, IL-6, IL-8, and MCP-1 showed a biphasic pattern in the H group, with early and delayed peaks. In H neonates with better outcomes, uniform down modulation of IL-6, IL-8, and IL-10 from their peak levels at 24 hours to their nadir at 36 hours was observed. Modulation of serum cytokines after HI injury may be another mechanism of improved outcomes in neonates treated with induced hypothermia.

Biomarkers of brain injury in neonatal encephalopathy treated with hypothermia

OBJECTIVE

To determine if early serum S100B and neuron-specific enolase (NSE) levels are associated with neuroradiographic and clinical evidence of brain injury in newborns with encephalopathy.

STUDY DESIGN

Patients who received therapeutic whole-body hypothermia were prospectively enrolled in this observational study. Serum specimens were collected at 0, 12, 24, and 72 hours of cooling. S100B and NSE levels were measured by enzyme linked immunosorbent assay. Magnetic resonance imaging was performed in surviving infants at 7-10 days of life. Standardized neurologic examination was performed by a child neurologist at 14 days of life. Multiple linear regression analyses were performed to evaluate the association between S100B and NSE levels and unfavorable outcome (death or severe magnetic resonance imaging injury/significant neurologic deficit). Cutoff values were determined by receiver operating curve analysis.

RESULTS

Newborns with moderate to severe encephalopathy were enrolled (n = 75). Median pH at presentation was 6.9 (range, 6.5-7.35), and median Apgar scores of 1 at 1 minute, 3 at 5 minutes, and 5 at 10 minutes. NSE and S100B levels were higher in patients with unfavorable outcomes across all time points. These results remained statistically significant after controlling for covariables, including encephalopathy grade at presentation, Apgar score at 5 minutes of life, initial pH, and clinical seizures.

CONCLUSION

Elevated serum S100B and NSE levels measured during hypothermia were associated with neuroradiographic and clinical evidence of brain injury in encephalopathic newborns. These brain-specific proteins may be useful immediate biomarkers of cerebral injury severity.

Matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in perinatal asphyxia

Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) play important roles in the function of the blood-brain-barrier (BBB). We investigated the roles of MMP-9 and TIMP-1 in the pathogenesis of hypoxic-ischemic encephalopathy following perinatal asphyxia. Serum concentrations of MMP-9 and TIMP-1 were determined by ELISA in 12 neonates with perinatal asphyxia and 15 controls on the birth day and the next day. Serum MMP-9 concentrations in asphyxiated neonates with neurological sequelae (n=5) were significantly higher than concentration in asphyxiated neonates without sequelae (n=7) and controls on birth day (p=0.003 and p<0.001, respectively). The ratios of serum MMP-9/TIMP-1 on birth day in asphyxiated neonates with neurological sequelae were significantly higher than those in asphyxiated neonates without sequelae (p=0.048). There were no significant differences in the serum MMP-9 concentrations or the ratios of MMP-9/TIMP-1 between asphyxiated neonates with and without neurological sequelae on the day after birth. Our preliminary study suggests that serum MMP-9 levels on birth day are important for predicting neurological prognosis of neonates with asphyxia.

Neuron-specific enolase and S-100B are associated with neurologic outcome after pediatric cardiac arrest

OBJECTIVE

To characterize the pattern of serum biochemical markers of central nervous system injury (neuron-specific enolase [NSE], S-100B, plasminogen activator inhibitor-1 [PAI-1]) after pediatric cardiac arrest and determine whether there is an association between biomarker concentrations and neurologic outcome.

DESIGN

Prospective, observational study.

SETTING

Urban, tertiary care children's hospital.

PATIENTS

Cardiac arrest survivors, n = 35.

INTERVENTIONS

Serial blood sampling, pediatric cerebral performance category, and standardized neurologic examination.

MEASUREMENTS AND MAIN RESULTS

Serial serum NSE and S-100B concentrations over 96 hrs and PAI-1 at 24 hrs were measured in children (age <18 yrs) who had return of spontaneous circulation following cardiac arrest. Neurologic outcome was prospectively categorized as poor if the change in pre- to postarrest pediatric cerebral performance category was > or =2. Biomarker concentrations were compared between outcome groups and between survival groups using longitudinal analysis correcting for multiple comparisons. Median levels (25th, 75th percentiles) are reported. Receiver operating characteristic analyses were performed at all time points. Biomarker concentrations showed statistically significant differences. Of the 35 patients, neurologic outcomes were poor in 19, with 15 deaths. Median NSE concentrations differed by outcome when measured at > or =48 hrs, and by survival at > or =24 hrs. S-100B concentrations were not significantly associated with neurologic outcome. S-100B levels were associated with survival outcome at > or =48 hrs. PAI-1 levels were not significantly associated with either neurologic or survival outcomes.

CONCLUSIONS

The timing, intensity, and duration of serum NSE and S-100B biomarker concentration patterns are associated with neurologic and survival outcomes following pediatric cardiac arrest. Serum NSE concentrations at > or =48 hrs are associated with neurologic outcome, whereas serum S-100B levels at > or =48 hrs are associated with survival. Prospective analysis of these markers may help to predict outcomes and guide postresuscitative therapies.

Systematic review of biomarkers of brain injury in term neonatal encephalopathy

Although neonatal hypoxic-ischemic encephalopathy is a common cause of childhood developmental disability, its timing, duration, and outcomes are poorly defined. Biomarkers serve as surrogates for disease injury, evolution, and outcome, but no tissue biomarker in routine clinical use can help predict outcomes in term newborn encephalopathy. We reviewed biomarkers in human term neonatal encephalopathy, to determine if current biomarkers are strong enough for clinical use as predictors of outcomes. A comprehensive search of databases identified 110 publications that met our inclusion criteria, i.e., (1) newborns at >36 weeks; (2) neonatal encephalopathy as defined by the American College of Obstetrics and Gynecology; (3) the use of a serum, urine, or cerebrospinal fluid biomarker; and (4) reported outcomes beyond age 12 months. Of those 110 publications, 22 reported outcomes beyond age 12 months. In single reports, urine lactate (P < 0.001), first urine S100 (P < 0.0001), cord-blood interleukin-6 (P = 0.02), serum nonprotein-bound iron (P < 0.001), serum CD14 cell NFkappaB activation (P = 0.014), serum interleukin-8 (P = 0.03), and serum ionized calcium (P = 0.001) were potential predictors of death or abnormal outcomes. A meta-analysis identified serum interleukin-1b (P = 0.04, n = 3), serum interleukin-6 (P = 0.04, n = 2), cerebrospinal fluid neuron-specific enolase (P = 0.03, n = 3), and cerebrospinal fluid interleukin-1b (P = 0.003, n = 2) as putative predictors of abnormal outcomes in survivors, when measured before age 96 hours. Several serum, urine, and cerebrospinal fluid biomarkers of term neonatal encephalopathy may provide important information regarding long-term outcomes. None, however, were studied extensively enough to warrant routine clinical use. Validation of these markers, either alone or in combination, is required in the development of viable therapeutic interventions.

Serum Biomarkers after Traumatic and Hypoxemic Brain Injuries: Insight into the Biochemical Response of the Pediatric Brain to Inflicted Brain Injury

Inflicted traumatic brain injury (iTBI) involves a combination of mechanical trauma and hypoxemia. Serum biomarker concentrations may provide objective information about their relative importance to the pathophysiology of iTBI. We compared the time course of neuron-specific enolase (NSE), S100B and myelin basic protein after pediatric hypoxic-ischemic brain injury, iTBI and noninflicted TBI (nTBI). The time to reach peak concentrations of all three biomarkers was shorter after nTBI. Initial and peak S100B, initial and peak myelin basic protein and peak NSE concentrations were no different between the three groups. Initial NSE concentration was highest after nTBI. These results suggest that the biochemical response of the brain to iTBI is distinct from the response to nTBI and shares temporal similarities with hypoxic-ischemic brain injury. This may have important implications for the treatment and prognosis of children with iTBI.

Interleukin-6 in the maternal circulation reaches the rat fetus in mid-gestation

Maternal systemic infection during pregnancy may expose the fetus to infectious agents and high levels of mediators of the resulting inflammatory response, such as IL-6 (IL-6). Increased fetal and maternal levels of IL-6 have been associated with adverse neonatal outcome but might also stress the fetus and contribute to cardiovascular and neuroendocrine dysfunction in adulthood. It is unclear whether interleukins cross the placental barrier, although this matter has been little studied. The aim of this study was therefore to investigate if IL-6 administered to pregnant rats in vivo is transferred to the fetus. We injected 125I IL-6 i.v. to pregnant dams at gestation day 11-13 (mid-gestation) or 17-19 (late gestation). We found 125I-IL-6 in the exposed fetuses as well as in amniotic fluids. Fetal 125I-IL-6 levels were markedly higher in animals injected in mid-gestation compared with late pregnancy (p < 0.01). This difference was mirrored in a 15-fold higher unidirectional materno-fetal clearance for 125I-IL-6 in mid-gestation (p < 0.01). We conclude that the permeability of the rat placental barrier to IL-6 is much higher in mid-gestation than in late pregnancy. Maternally derived IL-6 may directly induce fetal injury but also stimulate the release of fetal stress hormones resulting in stimuli or insults in neuroendocrine structures and hormonal axes which might lead to disease at adult age.

Perinatal infections and cerebral palsy

Infections of the mother, the intrauterine environment, the fetus, and the neonate can cause cerebral palsy through a variety of mechanisms. Each of these processes is reviewed. The recently proposed theory of cytokine-induced white matter brain injury and the systemic inflammatory response syndrome with multiple organ dysfunction syndrome is critically evaluated.

Hypoxic-ischemic encephalopathy in infants: new challenges

The subject of hypoxic-ischemic encephalopathy (HIE) is hardly new and yet remains an every day challenge to clinicians, mainly neonatologists and child neurologists. However, technological advances in neuroimaging do help in the diagnosis, but prevention of hypoxic-ischemic insults, ability to change the course of the disease, and treatment of the devastating consequences of HIE are lagging behind. With these issues in mind, we reviewed the literature on this subject and our own clinical experience in search of new developments in this area. The pathology and clinicopathologic correlates of HIE are emphasized as well.