Ernest M. Graham

White and gray matter development in human fetal, newborn and pediatric brains

Brain anatomy is characterized by dramatic growth from the end of the second trimester through the neonatal stage. The characterization of normal axonal growth of the white matter tracts has not been well-documented to date and could provide important clues to understanding the extensive inhomogeneity of white matter injuries in cerebral palsy (CP) patients. However, anatomical studies of human brain development during this period are surprisingly scarce and histology-based atlases have become available only recently. Diffusion tensor magnetic resonance imaging (DTMRI) can reveal detailed anatomy of white matter. We acquired diffusion tensor images (DTI) of postmortem fetal brain samples and in vivo neonates and children. Neural structures were annotated in two-dimensional (2D) slices, segmented, measured, and reconstructed three-dimensionally (3D). The growth status of various white matter tracts was evaluated on cross-sections at 19-20 gestational weeks, and compared with 0-month-old neonates and 5- to 6-year-old children. Limbic, commissural, association, and projection white matter tracts and gray matter structures were illustrated in 3D and quantitatively characterized to assess their dynamic changes. The overall pattern of the time courses for the development of different white matter is that limbic fibers develop first and association fibers last and commissural and projection fibers are forming from anterior to posterior part of the brain. The resultant DTMRI-based 3D human brain data will be a valuable resource for human brain developmental study and will provide reference standards for diagnostic radiology of premature newborns.

Necrostatin decreases oxidative damage, inflammation, and injury after neonatal HI

Necrostatin-1 inhibits receptor-interacting protein (RIP)-1 kinase and programmed necrosis and is neuroprotective in adult rodent models. Owing to the prominence of necrosis and continuum cell death in neonatal hypoxia–ischemia (HI), we tested whether necrostatin was neuroprotective in the developing brain. Postnatal day (P)7 mice were exposed to HI and injected intracerebroventricularly with 0.1 μL of 80 μmol necrostatin, Nec-1, 5-(1H-Indol-3-ylmethyl)-(2-thio-3-methyl) hydantoin, or vehicle. Necrostatin significantly decreased injury in the forebrain and thalamus at P11 and P28. There was specific neuroprotection in necrostatin-treated males. Necrostatin treatment decreased necrotic cell death and increased apoptotic cell death. Hypoxia–ischemia enforced RIP1–RIP3 complex formation and inhibited RIP3–FADD (Fas-associated protein with death domain) interaction, and these effects were blocked by necrostatin. Necrostatin also decreased HI-induced oxidative damage to proteins and attenuated markers of inflammation coincidental with decreased nuclear factor-κB and caspase 1 activation, and FLIP ((Fas-associated death-domain-like IL-1β-converting enzyme)-inhibitory protein) gene and protein expression. In this model of severe neonatal brain injury, we find that cellular necrosis can be managed therapeutically by a single dose of necrostatin, administered after HI, possibly by interrupting RIP1–RIP3-driven oxidative injury and inflammation. The effects of necrostatin treatment after HI reflect the importance of necrosis in the delayed phases of neonatal brain injury and represent a new direction for therapy of neonatal HI.

Intrapartum electronic fetal heart rate monitoring and the prevention of perinatal brain injury

OBJECTIVE: Electronic fetal heart rate monitoring (EFM) is the most widely used method of intrapartum surveillance, and our objective is to review its ability to prevent perinatal brain injury and death. DATA SOURCES: Studies that quantified intrapartum EFM and its relation to specific neurologic outcomes (seizures, periventricular leukomalacia, cerebral palsy, death) were eligible for inclusion. MEDLINE was searched from 1966 to 2006 for studies that examined the relationship between intrapartum EFM and perinatal brain injury using these MeSH and text words: “cardiotocography,” “electronic fetal monitoring,” “intrapartum fetal heart rate monitoring,” “intrapartum fetal monitoring,” and “fetal heart rate monitoring.” METHODS OF STUDY SELECTION: This search strategy identified 1,628 articles, and 41 were selected for further review. Articles were excluded for the following reasons: in case reports, letters, commentaries, and review articles, intrapartum EFM was not quantified, or specific perinatal neurologic morbidity was not measured. Three observational studies and a 2001 meta-analysis of 13 randomized controlled trials were selected for determination of the effect of intrapartum EFM on perinatal brain injury. TABULATION, INTEGRATION, AND RESULTS: Electronic fetal monitoring was introduced into widespread clinical practice in the late 1960s based on retrospective studies comparing its use to historical controls where auscultation was performed in a nonstandardized manner. Case-control studies have shown correlation of EFM abnormalities with umbilical artery base excess, but EFM was not able to identify cerebral white matter injury or cerebral palsy. Of 13 randomized controlled trials, one showed a significant decrease in perinatal mortality with EFM compared with auscultation. Meta-analysis of the randomized controlled trials comparing EFM with auscultation have found an increased incidence of cesarean delivery and decreased neonatal seizures but no effect on the incidence of cerebral palsy or perinatal death. CONCLUSION: Although intrapartum EFM abnormalities correlate with umbilical cord base excess and its use is associated with decreased neonatal seizures, it has no effect on perinatal mortality or pediatric neurologic morbidity.

The degree of antenatal ventriculomegaly is related to pediatric neurological morbidity

Objective: Our hypothesis was that the degree of antenatally diagnosed cerebral ventriculomegaly is related to aneuploidy, perinatal mortality and long-term neurological morbidity. Methods: Ninety-one cases of ventriculomegaly identified from 1 June 1994 to 1 July 1999 were examined for prenatal, intrapartum and neonatal complications. Pediatric follow-up was reviewed for infants with ventriculomegaly from birth up to as long as 4 years. Minor neurological morbidity was defined as a score of 70-80 on the clinical adaptive test/clinical linguistic and auditory milestone scale and included mild motor or language delay. Major morbidity included a score of < 70, evidence of cerebral palsy, or seizure disorder. The incidence of neurological complications was compared, on the basis of the degree of ventriculomegaly, with group 1 being > 10-15 mm and group 2 being > 15 mm. Results: Twenty-seven cases (18 with neural tube defects and nine with holoprosencephaly) were excluded. Among the remaining 64 patients, 39 had a ventricular diameter of > 10-15 mm and comprised group 1. Five of the 39 cases (12.8%), all with other ultrasound anomalies, elected to terminate. The incidence of aneuploidy in group 1 was 14.2%. Among the 19 cases with isolated ventriculomegaly, 17 (89%) were normal and two (11%) had minor neurological morbidity. In group 1 there were two cases associated with cytomegalovirus (CMV) infection. Of the 25 cases in group 2, eight (32%), all with other ultrasound anomalies, elected to terminate. The incidence of aneuploidy in group 2 was 17.4%. For the nine cases with isolated ventriculomegaly of > 15 mm, one (11%) was normal ( p < 0.001), five (56%) had minor neurological morbidity requiring a ventriculoperitoneal shunt ( p = 0.035), and three (33%) had major neurological morbidity ( p = 0.045) when compared to cases of isolated ventriculomegaly in group 1. There was one case of CMV infection in group 2. All perinatal deaths in both groups were associated with other anomalies. Conclusions: Amniocentesis to determine karyotype and the presence of CMV is warranted for all cases of ventriculomegaly of > 10 mm. The degree of antenatal ventriculomegaly is related to pediatric neurological morbidity and, when it is > 15 mm, it is associated with an increase in abnormal neurological development.

Glial fibrillary acidic protein as a biomarker for neonatal hypoxic-ischemic encephalopathy treated with whole-body cooling

OBJECTIVE Glial fibrillary acidic protein (GFAP) is specific to astrocytes in the central nervous system. We hypothesized that serum GFAP would be increased in neonates with hypoxic-ischemic encephalopathy (HIE) treated with whole-body cooling. STUDY DESIGN We measured GFAP at birth and daily for up to 7 days for neonates in the intensive care unit. We compared neonates with HIE treated with whole-body cooling to gestational age-matched controls without neurological injury and neonates with HIE by brain abnormalities on magnetic resonance imaging (MRI). RESULTS Neonates with HIE had increased GFAP levels compared with controls. Neonates with HIE and abnormal brain imaging had elevated GFAP levels compared with neonates with HIE and normal imaging. CONCLUSION Serum GFAP levels during the first week of life were increased in neonates with HIE and were predictive of brain injury on MRI. Biomarkers such as GFAP could help triage neonates with HIE to treatment, measure treatment efficacy, and provide prognostic information.

Glial fibrillary acidic protein as a brain injury biomarker in children undergoing extracorporeal membrane oxygenation

Objective: To determine whether, in children, plasma glial fibrillary acidic protein is associated with brain injury during extracorporeal membrane oxygenation and with mortality. Design: Prospective, observational study. Setting: Pediatric intensive care unit in an urban tertiary care academic center. Patients: Neonatal and pediatric patients on extracorporeal membrane oxygenation (n = 22). Interventions: Serial blood sampling for glial fibrillary acidic protein measurements. Measurements and Main Results: Prospective patients age 1 day to 18 yrs who required extracorporeal membrane oxygenation from April 2008 to August 2009 were studied. Glial fibrillary acidic protein was measured using an electrochemiluminescent immunoassay developed at Johns Hopkins. Control samples were collected from 99 healthy children (0.5–16 yrs) and 59 neonatal intensive care unit infants without neurologic injury. In controls, the median glial fibrillary acidic protein concentration was 0.055 ng/mL (interquartile range, 0–0.092 ng/mL) and the 95th percentile of glial fibrillary acidic protein was 0.436 ng/mL. In patients on extracorporeal membrane oxygenation, plasma glial fibrillary acidic protein was measured at 6, 12, and every 24 hrs after cannulation. We enrolled 22 children who underwent extracorporeal membrane oxygenation. Median age was 7 days (interquartile range, 2 days to 9 yrs), and primary extracorporeal membrane oxygenation indication was: cardiac failure, six of 22 (27.3%); respiratory failure, 12 of 22 (54.5%); extracorporeal cardiopulmonary resuscitation, three of 22 (13.6%); and sepsis, one of 22 (4.6%). Seven of 22 (32%) patients developed acute neurologic injury (intracranial hemorrhage, brain death, or cerebral edema diagnosed by imaging). Fifteen of 22 (68%) survived to hospital discharge. In the extracorporeal membrane oxygenation group, peak glial fibrillary acidic protein levels were higher in children with brain injury than those without (median, 5.9 vs. 0.09 ng/mL, p = .04) and in nonsurvivors compared with survivors to discharge (median, 5.9 vs. 0.09 ng/mL, p = .04). The odds ratio for brain injury for glial fibrillary acidic protein >0.436 ng/mL vs. normal was 11.5 (95% confidence interval, 1.3–98.3) and the odds ratio for mortality was 13.6 (95% confidence interval, 1.7–108.5). Conclusions: High glial fibrillary acidic protein during extracorporeal membrane oxygenation is significantly associated with acute brain injury and death. Brain injury biomarkers may aid in outcome prediction and neurologic monitoring of patients on extracorporeal membrane oxygenation to improve outcomes and benchmark new therapies.

Cord gas analysis, decision-to-delivery interval, and the 30-minute rule for emergency cesareans.

OBJECTIVE:Our primary objective was to examine the relationship between umbilical arterial gas analysis and decision-to-delivery interval for emergency cesareans performed for nonreassuring fetal status to determine if this would validate the 30-minute rule.STUDY DESIGN:For this retrospective cohort study, all cesarean deliveries performed for nonreassuring fetal status from September 2001 to January 2003 were reviewed. A synopsis of clinical information that would have been available to the clinician at the time of delivery and the last hour of the electronic fetal heart rate tracing prior to delivery were reviewed by three different maternal–fetal medicine specialists masked to outcome, who classified each delivery as either emergent (delivery as soon as possible) or urgent (willing to wait up to 30 minutes for delivery) since immediacy of the fetal condition is the key factor affecting the type of anesthesia used.RESULTS:Of 145 cesareans performed for nonreassuring fetal status during this period, 117 patients met criteria for entry, of which 34 were classified as emergent and 83 as urgent. Kappa correlation was 0.35, showing only fair/moderate agreement between reviewers. In the emergent group, general anesthesia was more common (35.3%, 10.8%, p=0.003), and the decision-to-delivery interval was 14 minutes shorter (23.0±15.3, 36.7±14.9 minutes, p<0.001). Linear regression showed a statistically significant relationship between increasing decision-to-delivery interval and umbilical arterial pH (r=0.22, p=0.02) and base excess (r=0.33, p<0.001) showing that delivery proceeded sooner for most of those with the worst cord gases, with a gradual improvement over time. For the 13 (11%) neonates with cord gases placing them at increased risk for long-term neurologic sequelae, the decision-to-delivery interval was 24.7±14.6 minutes (range 6 to 50 minutes), and 3/13 (23%) were classified as urgent rather than emergent.CONCLUSION:Electronic fetal monitoring shows considerable variation in interpretation among maternal–fetal medicine specialists and is not a sensitive predictor of the fetus developing metabolic acidosis. There is no deterioration in cord gas results after 30 minutes, and most neonates delivered emergently or urgently for nonreassuring fetal status even when born after 30 minutes have normal cord gases. The 30-minute rule is a compromise that reflects the time it takes the fetus to develop severe metabolic acidosis, our imprecision in its identification, and its rarity in the presence of nonreassuring fetal monitoring.

Association of prematurity and neonatal infection with neurologic morbidity in very low birth weight infants

OBJECTIVE To identify risk factors predictive of neurologic morbidity in very low birth weight (VLBW) infants. METHODS This is a case–control study of all infants weighing 1500 g or less admitted to a single tertiary neonatal intensive care unit between April 1999 and December 2001. The case group were those neonates with neurologic morbidity including intraventricular hemorrhage, seizures, hydrocephalus, and periventricular leukomalacia. The control group were those without neurologic morbidity. Wilcoxon rank-sum, Fisher exact test, χ2, and univariate and stepwise multiple logistic regression were performed, with P < 0.05 considered significant. RESULTS Of 213 VLBW infants, 77 had neurologic morbidity: 61 had intraventricular hemorrhage, eight had seizures, 13 had hydrocephalus, and nine had periventricular leukomalacia. Several infants had more than one morbidity. Gestational age (odds ratio [OR] 0.95; 95% confidence interval [CI] 0.94, 0.96; P < .005), birth weight (OR 0.62; 95% CI 0.49, 0.79; P < .005), and neonatal infection (OR 1.36; 95% CI 1.17, 1.58; P < .005) were highly associated with neurologic morbidity. There was no difference in mean umbilical arterial cord pH (7.25 ± 0.15, 7.28 ± 0.09, P = .45) or base excess (−3.8 ± 4.8 mEq/L, −2.3 ± 3.0, P = .10). Only three of 52 infants (5.8%) in the case group had an umbilical arterial pH of less than 7. CONCLUSION Prematurity and neonatal infection were the dominant factors associated with neurologic morbidity in VLBW infants. Intrapartum acidosis occurred in less than 6% of those with neurologic morbidity.

Diagnostic accuracy of fetal heart rate monitoring in the identification of neonatal encephalopathy.

OBJECTIVE: To estimate the diagnostic accuracy of electronic fetal heart rate abnormalities in the identification of neonates with encephalopathy treated with whole-body hypothermia. METHODS: Between January 1, 2007, and July 1, 2013, there were 39 neonates born at two hospitals within our system treated with whole-body hypothermia within 6 hours of birth. Neurologically normal control neonates were matched to each case by gestational age and mode of delivery in a two-to-one fashion. The last hour of electronic fetal heart rate monitoring before delivery was evaluated by three obstetricians blinded to outcome. RESULTS: The differences in tracing category were not significantly different (neonates in the case group 10.3% I, 76.9% II, 12.8% III; neonates in the control group 9.0% I, 89.7% II, 1.3% III; P=.18). Bivariate analysis showed neonates in the case group had significantly increased late decelerations, total deceleration area 30 (debt 30) and 60 minutes (debt 60) before delivery and were more likely to be nonreactive. Multivariable logistic regression showed neonates in the case group had a significant decrease in early decelerations (P=.03) and a significant increase in debt 30 (.01) and debt 60 (P=.005). The area under the receiver operating characteristic curve, sensitivity, and specificity were 0.72, 23.1%, and 94.9% for early decelerations; 0.66, 33.3%, and 87.2% for debt 30, and 0.68, 35.9%, and 89.7% for debt 60, respectively. CONCLUSION: Abnormalities during the last hour of fetal heart rate monitoring before delivery are poorly predictive of neonatal hypoxic–ischemic encephalopathy qualifying for whole-body hypothermia treatment within 6 hours of birth. LEVEL OF EVIEDENCE: II

Neonatal nucleated red blood cells and the prediction of cerebral white matter injury in preterm infants.

OBJECTIVE: To estimate whether neonates with cerebral white matter injury have significant elevations in nucleated red blood cell counts and to estimate their predictive ability in identifying injury. METHODS: This case–control study identified 176 infants born at 23–34 weeks of gestation between November 1994 and October 2004 at a single university hospital and with cerebral white matter injury characterized by periventricular leukomalacia (PVL) or ventriculomegaly due to white matter atrophy. A control was matched to each case using the subsequent delivery within 7 days of that gestational age without brain injury. RESULTS: The gestational age at birth was 27 weeks for both groups, but the cases had a significantly lower birth weight (mean ± standard deviation: 958 ± 306 g compared with 1,038 ± 381 g, P = .001). There was no difference in cesarean delivery (48% cases compared with 44% controls, P = .59). The cases had a significant increase in nucleated red blood cells per 100 white blood cells (WBC) (median, 5th percentile and 95th percentile: 22, 3 and 374 cases compared with 14, 1 and 312 controls; P = .02). Markers of chronic hypoxia, such as intrauterine growth restriction and oligohydramnios, and markers of acute hypoxia, such as an umbilical arterial pH less than 7.0 or base excess less than −12 mM, were both associated with significantly elevated neonatal nucleated red blood cell counts. A neonatal nucleated red blood cell count of 18 per 100 WBCs had a sensitivity of 56.9%, specificity of 57.9%, positive predictive value of 57.9%, and negative predictive value of 56.9% in predicting the development of cerebral white matter injury in this matched case–control sample. CONCLUSION: Preterm neonates with cerebral white matter injury have significant increases in nucleated red blood cell counts. Both acute and chronic hypoxia–ischemia can increase these counts, which limits their usefulness in timing injury. The predictive value of nucleated red blood cell counts at birth in identifying injury is poor. LEVEL OF EVIDENCE: II-2