Alexis S. Davis

Human Neural Stem Cell Grafts Modify Microglial Response and Enhance Axonal Sprouting in Neonatal Hypoxic–Ischemic Brain Injury

Background and Purpose— Hypoxic–ischemic (HI) brain injury in newborn infants represents a major cause of cerebral palsy, development delay, and epilepsy. Stem cell-based therapy has the potential to rescue and replace the ischemic tissue caused by HI and to restore function. However, the mechanisms by which stem cell transplants induce functional recovery are yet to be elucidated. In the present study, we sought to investigate the efficacy of human neural stem cells derived from human embryonic stem cells in a rat model of neonatal HI and the mechanisms enhancing brain repair. Methods— The human neural stem cells were genetically engineered for in vivo molecular imaging and for postmortem histological tracking. Twenty-four hours after the induction of HI, animals were grafted with human neural stem cells into the forebrain. Motor behavioral tests were performed the fourth week after transplantation. We used immunocytochemistry and neuroanatomical tracing to analyze neural differentiation, axonal sprouting, and microglia response. Treatment-induced changes in gene expression were investigated by microarray and quantitative polymerase chain reaction. Results— Bioluminescence imaging permitted real time longitudinal tracking of grafted human neural stem cells. HI transplanted animals significantly improved in their use of the contralateral impeded forelimb and in the Rotorod test. The grafts showed good survival, dispersion, and differentiation. We observed an increase of uniformly distributed microglia cells in the grafted side. Anterograde neuroanatomical tracing demonstrated significant contralesional sprouting. Microarray analysis revealed upregulation of genes involved in neurogenesis, gliogenesis, and neurotrophic support. Conclusions— These results suggest that human neural stem cell transplants enhance endogenous brain repair through multiple modalities in response to HI.

Seizures in extremely low birth weight infants are associated with adverse outcome.

OBJECTIVE To examine risk factors for neonatal clinical seizures and to determine the independent association with death or neurodevelopmental impairment (NDI) in extremely low birth weight (ELBW) infants. STUDY DESIGN A total of 6499 ELBW infants (401-1000 g) surviving to 36 weeks postmenstrual age (PMA) were included in this retrospective study. Unadjusted comparisons were performed between infants with (n = 414) and without (n = 6085) clinical seizures during the initial hospitalization. Using multivariate logistic regression modeling, we examined the independent association of seizures with late death (after 36 weeks PMA) or NDI after controlling for multiple demographic, perinatal, and neonatal variables. RESULTS Infants with clinical seizures had a greater proportion of neonatal morbidities associated with poor outcome, including severe intraventricular hemorrhage, sepsis, meningitis, and cystic periventricular leukomalacia (all P < .01). Survivors were more likely to have NDI or moderate-severe cerebral palsy at 18 to 22 months corrected age (both P < .01). After adjusting for multiple confounders, clinical seizures remained significantly associated with late death or NDI (odds ratio, 3.15; 95% CI, 2.37-4.19). CONCLUSION ELBW infants with clinical seizures are at increased risk for adverse neurodevelopmental outcome, independent of multiple confounding factors.

Gene therapy using SOD1 protects striatal neurons from experimental stroke.

Reactive oxygen species contribute to neuronal death following cerebral ischemia. Prior studies using transgenic animals have demonstrated the neuroprotective effect of the antioxidant, copper/zinc superoxide dismutase (SOD1). In this study, we investigated whether SOD1 overexpression using gene therapy techniques in non-transgenic animals would increase neuronal survival. A neurotropic, herpes simplex virus-1 (HSV-1) vector containing the SOD1 gene was injected into the striatum either before or after transient focal cerebral ischemia. Striatal neuron survival at 2 days was improved by 52% when vector was delivered 12-15 h prior to ischemia and by 53% when vector delivery was delayed 2 h following ischemia. These data add to the growing literature, which suggests that an antioxidant approach, perhaps by employing gene therapy techniques, may be beneficial in the treatment of stroke.

A Randomized Clinical Trial of Therapeutic Hypothermia Mode during Transport for Neonatal Encephalopathy

OBJECTIVE To determine if temperature regulation is improved during neonatal transport using a servo-regulated cooling device when compared with standard practice. STUDY DESIGN We performed a multicenter, randomized, nonmasked clinical trial in newborns with neonatal encephalopathy cooled during transport to 9 neonatal intensive care units in California. Newborns who met institutional criteria for therapeutic hypothermia were randomly assigned to receive cooling according to usual center practices vs device servo-regulated cooling. The primary outcome was the percentage of temperatures in target range (33°-34°C) during transport. Secondary outcomes included percentage of newborns reaching target temperature any time during transport, time to target temperature, and percentage of newborns in target range 1 hour after cooling initiation. RESULTS One hundred newborns were enrolled: 49 to control arm and 51 to device arm. Baseline demographics did not differ with the exception of cord pH. For each subject, the percentage of temperatures in the target range was calculated. Infants cooled using the device had a higher percentage of temperatures in target range compared with control infants (median 73% [IQR 17-88] vs 0% [IQR 0-52], P < .001). More subjects reached target temperature during transport using the servo-regulated device (80% vs 49%, P <.001), and in a shorter time period (44 ± 31 minutes vs 63 ± 37 minutes, P = .04). Device-cooled infants reached target temperature by 1 hour with greater frequency than control infants (71% vs 20%, P < .001). CONCLUSIONS Cooling using a servo-regulated device provides more predictable temperature management during neonatal transport than does usual care for outborn newborns with neonatal encephalopathy.

Outcomes of extremely low birthweight infants with acidosis at birth

Objectives To test the hypothesis that acidosis at birth is associated with the combined primary outcome of death or neurodevelopmental impairment (NDI) in extremely low birthweight (ELBW) infants, and to develop a predictive model of death/NDI exploring perinatal acidosis as a predictor variable. Study design The study population consisted of ELBW infants born between 2002 and 2007 at National Institute of Child Health and Development (NICHD) Neonatal Research Network hospitals. Infants with cord blood gas data and documentation of either mortality prior to discharge or 18–22 month neurodevelopmental outcomes were included. Multiple logistic regression analysis was used to determine the contribution of perinatal acidosis, defined as a cord blood gas with a pH<7 or base excess (BE) <−12, to death/NDI in ELBW infants. In addition, a multivariable model predicting death/NDI was developed. Results 3979 patients were identified of whom 249 had a cord gas pH<7 or BE<−12 mEq/L. 2124 patients (53%) had the primary outcome of death/NDI. After adjustment for confounding variables, pH<7 and BE<−12 mEq/L were each significantly associated with death/NDI (OR=2.5 (1.6, 4.2) and OR=1.5 (1.1, 2.0), respectively). However, inclusion of pH or BE did not improve the ability of the multivariable model to predict death/NDI. Conclusions Perinatal acidosis is significantly associated with death/NDI in ELBW infants. Perinatal acidosis is infrequent in ELBW infants, however, and other factors are more important in predicting death/NDI.

Therapeutic hypothermia during neonatal transport: data from the California Perinatal Quality Care Collaborative (CPQCC) and California Perinatal Transport System (CPeTS) for 2010

Objective:To evaluate cooling practices and neonatal outcomes in the state of California during 2010 using the California Perinatal Quality Care Collaborative and California Perinatal Transport System databases.Study Design:Database analysis to determine the perinatal and neonatal demographics and outcomes of neonates cooled in transport or after admission to a cooling center.Result:Of the 223 infants receiving therapeutic hypothermia for hypoxic ischemic encephalopathy (HIE) in California during 2010, 69% were cooled during transport. Despite the frequent use of cooling in transport, cooling center admission temperature was in the target range (33–34 °C) in only 62 (44%). Among cooled infants, gestational age was <35 weeks in 10 (4.5%). For outborn and transported infants, chronologic age at the time of cooling initiation was >6 h in 20 (11%). When initiated at the birth hospital, cooling was initiated at <6 h of age in 131 (92.9%).Conclusion:More than half of the infants cooled in transport do not achieve target temperature by the time of arrival at the cooling center. The use of cooling devices may improve temperature regulation on transport.

Outcomes of extremely preterm infants following severe intracranial hemorrhage

Objective:Severe intracranial hemorrhage (ICH) is an important prognostic variable in extremely preterm (EPT) infants. We examined imaging and clinical variables that predict outcomes in EPT infants with severe ICH.Study design:Retrospective analysis of 353 EPT infants with severe ICH. Outcomes were compared by examining: (i) unilateral vs bilateral ICH; and (ii) presence vs absence of hemorrhagic parenchymal infarction (HPI). Regression analyses identified variables associated with death or neurodevelopmental impairment (NDI).Result:Bilateral ICH and HPI had higher rates of adverse outcomes and were independently associated with death/NDI. HPI was the most important variable for infants of lower birth weight, and bilateral ICH for larger infants. For infants surviving to 36 weeks, shunt placement was most associated with death/NDI.Conclusion:Bilateral ICH and the presence of HPI in EPT infants with severe ICH are associated with death/NDI, though the importance depends on birth weight and survival to 36 weeks.

Peripartum and neonatal outcomes of small‐for‐gestational‐age infants with gastroschisis

Neonates with gastroschisis are often small for gestational age (SGA) based on population nomograms. Our objective was to evaluate the effect of SGA on perinatal and neonatal outcomes in cases of gastroschisis.

Prediction of neonatal respiratory distress in pregnancies complicated by fetal lung masses

The objective of this article is to evaluate the utility of fetal lung mass imaging for predicting neonatal respiratory distress.

Perinatal Neuroprotection for Extremely Preterm Infants.

The preterm brain is vulnerable to injury through multiple mechanisms, from direct cerebral injury through ischemia and hemorrhage, indirect injury through inflammatory processes, and aberrations in growth and development. While prevention of preterm birth is the best neuroprotective strategy, this is not always possible. This article will review various obstetric and neonatal practices that have been shown to confer a neuroprotective effect on the developing brain.