Plasma Biomarkers of Evolving Encephalopathy and Brain Injury in Neonates with Hypoxic-Ischemic Encephalopathy.

OBJECTIVE: The objective of the study was to evaluate the relationship between a panel of candidate plasma biomarkers and (1) death or severe brain injury on magnetic resonance imaging (MRI) and (2) dysfunctional cerebral pressure autoregulation as a measure of evolving encephalopathy. STUDY DESIGN: Neonates with moderate-to-severe hypoxic-ischemic encephalopathy (HIE) at 2 level IV neonatal intensive care units were enrolled into this observational study. Patients were treated with therapeutic hypothermia (TH) and monitored with continuous blood pressure monitoring and near-infrared spectroscopy. Cerebral pressure autoregulation was measured by the hemoglobin volume phase (HVP) index; a higher HVP index indicates poorer autoregulation. Serial blood samples were collected during TH and assayed for Tau, glial fibrillary acidic protein, and neurogranin. MRIs were assessed using National Institutes of Child Health and Human Development scores. The relationships between the candidate biomarkers and (1) death or severe brain injury on MRI (defined as a National Institutes of Child Health and Human Development score of ≥ 2B) and (2) autoregulation were evaluated using bivariate and adjusted logistic regression models. RESULTS: Sixty-two patients were included. Elevated Tau levels on days 2-3 of TH were associated with death or severe injury on MRI (aOR: 1.06, 95% CI: 1.03-1.09; aOR: 1.04, 95% CI: 1.01-1.06, respectively). Higher Tau was also associated with poorer autoregulation (higher HVP index) on the same day (P = .022). CONCLUSIONS: Elevated plasma levels of Tau are associated with death or severe brain injury by MRI and dysfunctional cerebral autoregulation in neonates with HIE. Larger-scale validation of Tau as a biomarker of brain injury in neonates with HIE is warranted.

The Utility of Cerebral Autoregulation Indices in Detecting Severe Brain Injury Varies by Cooling Treatment Phase in Neonates with Hypoxic-Ischemic Encephalopathy.

Identifying the hemodynamic range that best supports cerebral perfusion using near infrared spectroscopy (NIRS) autoregulation monitoring is a potential physiologic marker for neonatal hypoxic-ischemic encephalopathy (HIE) during therapeutic hypothermia. However, an optimal autoregulation monitoring algorithm has not been identified for neonatal clinical medicine. We tested whether the hemoglobin volume phase (HVP), hemoglobin volume (HVx), and pressure passivity index (PPI) identify changes in autoregulation that are associated with brain injury on MRI or death. The HVP measures the phase difference between a NIRS metric of cerebral blood volume, the total hemoglobin (THb), and mean arterial blood pressure (MAP) at the frequency of maximum coherence. The HVx is the correlation coefficient between MAP and THb. The PPI is the percentage of coherent MAP-DHb (difference between oxygenated and deoxygenated hemoglobin, a marker of cerebral blood flow) epochs in a chosen time period. Neonates cooled for HIE were prospectively enrolled in an observational study in two neonatal intensive care units. In analyses adjusted for study site and encephalopathy level, all indices detected relationships between poor autoregulation in the first 6 h after rewarming with a higher injury score on MRI. Only HVx and PPI during hypothermia and the PPI during rewarming identified autoregulatory dysfunction associated with a poor outcome independent of study site and encephalopathy level. Our findings suggest that the accuracy of mathematical autoregulation algorithms in detecting the risk of brain injury or death may depend on temperature and postnatal age. Extending autoregulation monitoring beyond the standard 72 h of therapeutic hypothermia may serve as a method to provide personalized care by assessing the need for and efficacy of future therapies after the hypothermia treatment phase.

The Application of Neurodiagnostic Studies to Inform the Acute Management of a Newborn Presenting With Sarbamoyl Shosphate Synthetase 1 Deficiency.

Neonatal-onset urea cycle disorders (UCDs) may result in hyperammonemic (HA) encephalopathy presenting with several neurologic sequelae including seizures, coma, and death. However, no recommendations are given in how and when neurodiagnostic studies should be used to screen or assess for these neurologic complications. We present a case of carbamoyl phosphate synthetase 1 (CPS1) deficiency in a newborn female in which electroencephalogram monitoring to assess encephalopathy and seizures, and magnetic resonance imaging measurements of brain metabolites were used to guide care during her hyperammonemic crisis. Her neurologic course and response to treatment characterizes the significant neurologic impact of HA encephalopathy. Our group herein proposes a clinical neurodiagnostic pathway for managing acute HA encephalopathy.

Serial plasma biomarkers of brain injury in infants with neonatal encephalopathy treated with therapeutic hypothermia.

BACKGROUND: Neonatal encephalopathy (NE) is a major cause of long-term neurodevelopmental disability in neonates. We evaluated the ability of serially measured biomarkers of brain injury to predict adverse neurological outcomes in this population. METHODS: Circulating brain injury biomarkers including BDNF, IL-6, IL-8, IL-10, VEGF, Tau, GFAP, and NRGN were measured at 0, 12, 24, 48, 72, and 96 h of cooling from 103 infants with NE undergoing TH. The biomarkers' individual and combinative ability to predict death or severe brain injury and adverse neurodevelopmental outcomes beyond 1 year of age was assessed. RESULTS: Early measurements of inflammatory cytokines IL-6, 8, and 10 within 24 HOL (AUC = 0.826) and late measurements of Tau from 72 to 96 HOL (AUC = 0.883, OR 4.37) were accurate in predicting severe brain injury seen on MRI. Late measurements of Tau were predictive of adverse neurodevelopmental outcomes (AUC = 0.81, OR 2.59). CONCLUSIONS: Tau was consistently a predictive marker for brain injury in neonates with NE. However, in the first 24 HOL, IL-6, 8, and 10 in combination were most predictive of death or severe brain injury. The results of this study support the use of a serial biomarker panel to assess brain injury over the time course of disease in NE. IMPACT: While recent studies have evaluated candidate brain injury biomarkers, no biomarker is in current clinical use. This study supports the use of a serial biomarker panel for ongoing assessment of brain injury neonates with NE. In combination, IL6, IL8, and IL10 in the first 24 h of cooling were more predictive of brain injury by MRI than each cytokine alone. Individually, Tau was overall most consistently predictive of adverse neurological outcomes, particularly when measured at or after rewarming.

Plasma and Cerebrospinal Fluid Candidate Biomarkers of Neonatal Encephalopathy Severity and Neurodevelopmental Outcomes.

OBJECTIVES: To identify candidate biomarkers in both plasma and cerebrospinal fluid (CSF) that are associated with neonatal encephalopathy severity measured by encephalopathy grade, seizures, brain injury by magnetic resonance imaging (MRI), and neurodevelopmental outcomes at 15-30 months. STUDY DESIGN: A retrospective cohort study of plasma (N = 155, day of life 0-1) and CSF (n = 30, day of life 0-7) from neonates with neonatal encephalopathy and healthy neonates born at term (N = 30, ≥36 weeks of gestation) was conducted. We measured central nervous system necrosis (glial fibrillary acidic protein [GFAP], neurogranin [NRGN], tau), inflammatory (interleukin [IL]-6, IL-8, IL-10), and trophic (brain-derived neurotrophic factor [BDNF], vascular endothelial growth factor) proteins. Clinical outcomes were Sarnat scores of encephalopathy, seizures, MRI scores, and Bayley Scales of Infant and Toddler Development III at 15-30 months. RESULTS: Plasma NRGN, tau, IL-6, IL-8, and IL-10 were greater, whereas BDNF and vascular endothelial growth factor were lower in patients with neonatal encephalopathy vs controls. In plasma, tau, GFAP, and NRGN were directly and BDNF inversely associated with encephalopathy grade. IL-6 was inversely related to seizures. Tau was directly related to MRI abnormalities. Tau was inversely associated with Bayley Scales of Infant and Toddler Development III cognitive and motor outcomes. In CSF, NRGN was inversely associated with cognitive, motor, and language measures. GFAP, IL-6, and IL-10 were inversely related to cognitive and motor outcomes. IL-8 was inversely related to motor outcomes. CSF candidate biomarkers showed no significant relationships with encephalopathy grade, seizures, or MRI abnormalities. CONCLUSIONS: Plasma candidate biomarkers predicted encephalopathy severity, seizures, MRI abnormalities, and neurodevelopmental outcomes at 15-30 months.