Umbilical cord blood concentrations of ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) and glial fibrillary acidic protein (GFAP) in neonates developing hypoxic-ischemic encephalopathy

The game changer: UCH-L1 and GFAP-based blood test as the first marketed in vitro diagnostic test for mild traumatic brain injury

INTRODUCTION

Major organ-based in vitro diagnostic (IVD) tests like ALT/AST for the liver and cardiac troponins for the heart are established, but an approved IVD blood test for the brain has been missing, highlighting a gap in medical diagnostics.

AREAS COVERED

In response to this need, Abbott Diagnostics secured FDA clearance in 2021 for the i-STAT Alinity™, a point-of-care plasma blood test for mild traumatic brain injury (TBI). BioMerieux VIDAS, also approved in Europe, utilizes two brain-derived protein biomarkers: neuronal ubiquitin C-terminal hydrolase-L1 (UCH-L1) and glial fibrillary acidic protein (GFAP). These biomarkers, which are typically present in minimal amounts in healthy individuals, are instrumental in diagnosing mild TBI with potential brain lesions. The study explores how UCH-L1 and GFAP levels increase significantly in the bloodstream following traumatic brain injury, aiding in early and accurate diagnosis.

EXPERT OPINION

The introduction of the i-STAT Alinity™ and the Biomerieux VIDAS TBI blood tests mark a groundbreaking development in TBI diagnosis. It paves the way for the integration of TBI biomarker tools into clinical practice and therapeutic trials, enhancing the precision medicine approach by generating valuable data. This advancement is a critical step in addressing the long-standing gap in brain-related diagnostics and promises to revolutionize the management and treatment of mild TBI.

Serum biomarkers of hypoxic-ischemic brain injury

Brain injury is a multifaceted condition arising from nonspecific damage to nervous tissue. The resulting cognitive developmental impairments reverberate through patients' lives, affecting their families, and even the broader economic landscape. The significance of early brain injury detection lies in its potential to stave off severe consequences and enhance the effectiveness of tailored therapeutic interventions. While established methods like neuroimaging and neurophysiology serve as valuable diagnostic tools, their demanding nature restricts their accessibility, particularly in scenarios such as small hospitals, nocturnal or weekend shifts, and cases involving unstable patients. Hence, there is a pressing need for more accessible and efficient diagnostic avenues. Among the spectrum of brain injuries, hypoxic-ischemic encephalopathy stands out as a predominant affliction in the pediatric population. Diagnosing brain injuries in newborns presents challenges due to the subjective nature of assessments like Apgar scores and the inherent uncertainty in neurological examinations. In this context, methods like magnetic resonance and ultrasound hold recommendations for more accurate diagnosis. Recognizing the potential of serum biomarkers derived from blood samples, this paper underscores their promise as a more expedient and resource-efficient means of assessing brain injuries. The review compiles current insights into serum biomarkers, drawing from experiments conducted on animal models as well as human brain pathologies. The authors aim to elucidate specific characteristics, temporal profiles, and the available corpus of experimental and clinical data for serum biomarkers specific to brain injuries. These include neuron-specific enolase (NSE), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), S100 calcium-binding protein beta (S100B), glial fibrillary acidic protein (GFAP), and high-mobility-group-protein-box-1 (HMGB1). This comprehensive endeavor contributes to advancing the understanding of brain injury diagnostics and potential avenues for therapeutic intervention.

Effect of maternal serum magnesium and calcium levels on umbilical glial fibrillary acidic protein levels in preterm labor

Magnesium can prevent astrocyte cell death and Glial Fibrillary Acidic Protein (GFAP) secretion as inflammatory marker in preterm delivery. This study was performed to analyze differences in umbilical cord GFAP levels in preterm labor given magnesium sulfate (MgSO4) as treatment group and control group and analyze the correlation between magnesium and calcium levels with umbilical GFAP levels. This quasi-experimental study was performed on 68 patients at Dr. Hasan Sadikin General Hospital from February-June 2021 consisting of 34 patients in each group. Maternal-umbilical cord magnesium levels, calcium levels, and GFAP levels were examined using ELISA test. The result was statistically measured by IBM SPSS 24.0. We found that there was a significant difference between maternal and umbilical magnesium levels and GFAP umbilical cord blood levels between the treatment and the control group (P < 0.05) in which GFAP level was higher in the control group. The multivariate analysis showed no significant relevance between mother magnesium and calcium level to umbilical cord GFAP level in the MgSO4 group. As conclusions, umbilical cord blood GFAP levels in preterm labor given MgSO4 were lower than in preterm deliveries who were not given MgSO4. There was no correlation between magnesium, calcium, and GFAP levels in the treatment group.

The Usefulness of Serum Brain Damage Biomarkers in Detection and Evaluation of Hypoxic Ischemic Encephalopathy in Calves with Perinatal Asphyxia

The purpose of the present study was to determine hypoxic brain damage in calves with perinatal asphyxia using brain-specific damage biomarkers. Ten healthy and 25 calves with perinatal asphyxia were enrolled in the study. Clinical examination, neurological status score, and laboratory analysis were performed at admission, 24, 48, and 72 h. Serum concentrations of ubiquitin carboxy-terminal hydrolysis 1 (UCHL1), calcium-binding protein B (S100B), adrenomodullin (ADM), activitin A (ACTA), neuron-specific enolase (NSE), glial fibrillary acidic protein (GFAP) and creatine kinase-brain (CK-B) were measured. Histopathological and immunohistochemical examinations of the brain tissue were performed in 13 nonsurvivor calves. The neurological status score of the calves with asphyxia was significantly (p < 0.05) lower. Mix metabolic-respiratory acidosis and hypoxemia were detected in calves with asphyxia. Serum UCHL1 and S100B were significantly (p < 0.05) increased, and NSE, ACTA, ADM, and CK-B were decreased (p < 0.05) in calves with asphyxia. Histopathological and immunohistochemical examinations confirmed the development of mild to severe hypoxic-ischemic encephalopathy. In conclusion, asphyxia and hypoxemia caused hypoxic-ischemic encephalopathy in perinatal calves. UCHL1 and S100B concentrations were found to be useful markers for the determination of hypoxic-ischemic encephalopathy in calves with perinatal asphyxia. Neurological status scores and some blood gas parameters were helpful in mortality prediction.

Concentration of Serum Biomarkers of Brain Injury in Neonates With a Low Cord pH With or Without Mild Hypoxic-Ischemic Encephalopathy

Objective

To determine the concentrations of four neuroprotein biomarkers and 68 miRNAs in neonates with low cord pH and/or mild hypoxic-ischemic encephalopathy (HIE).

Study Design

A prospective cohort study enrolled neonates with low cord pH (n = 18), moderate-severe HIE (n = 40), and healthy controls (n = 38). Groups provided serum samples at 0–6 h of life. The concentrations of biomarkers and miRNAs were compared between cohorts.

Result

The low cord pH and moderate-severe HIE groups had increased concentrations of GFAP, NFL and Tau compared to controls (P < 0.05, P < 0.001, respectively). NFL concentrations in mild HIE was higher than controls (P < 0.05) but less than moderate-severe HIE (P < 0.001). Of 68 miRNAs, 36 in low cord pH group and 40 in moderate-severe HIE were upregulated compared to controls (P < 0.05). Five miRNAs in low cord pH group (P < 0.05) and 3 in moderate-severe HIE were downregulated compared to controls (P < 0.05).

Conclusion

A biomarker panel in neonates with low cord pH may help clinicians make real-time decisions.

Prognostic neurobiomarkers in neonatal encephalopathy

Therapeutic hypothermia is now standard-care for infants with moderate-severe neonatal encephalopathy (NE), and improves brain damage on neuroimaging, and neurodevelopmental outcomes. Critically, for effective neuroprotection, hypothermia should be started within 6 h from birth. There is compelling evidence to suggest that a proportion of infants with mild NE have material risk of developing brain damage and poor outcomes. This cohort is increasingly being offered therapeutic hypothermia, despite lack of trial evidence for its benefit. In current practice, infants need to be diagnosed within 6 h of birth for therapeutic treatment, compared to retrospective NE grading in the pre-hypothermia era. This presents challenges as NE is a dynamic brain disorder that can worsen or resolve over time. Neurological symptoms of NE can be difficult to discern in the first few hours after birth, and confounded by analgesics and anesthetic treatment. Using current enrolment criteria, a significant number of infants with NE that would benefit from hypothermia are not treated, and vice versa, infants are receiving mild hypothermia when its benefit will be limited. Better biomarkers are needed to further improve management and treatment of these neonates. In the present review, we examine the latest research, and highlight a central limitation of most current biomarkers: that their predictive value is consistently greatest after most neuroprotective therapies are no longer effective.

The expression and clinical value of ubiquitin carboxyl-terminal hydrolase L1 in the blood of neonates with hypoxic ischemic encephalopathy

BACKGROUND

Neonatal hypoxic ischemic encephalopathy (HIE) can result in mental retardation due to the associated brain damage. Early identification of brain injury is vital for the prevention and treatment of brain damage in neonates. This study investigated the expression levels of serum ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) in neonates with HIE and its correlation with brain damage.

METHODS

From January 2019 to December 2020, 56 cases of neonatal patients with HIE were selected as the observation group, and 60 cases of healthy newborns delivered in our hospital during the same period were selected as the control group. Blood samples were obtained from neonates and the serum expression of UCH-L1 was detected by enzyme-linked immunosorbent assays (ELISAs). The relationship between UCH-L1 and neonatal prognosis and clinical features was analyzed.

RESULTS

Compared with the healthy control group, the serum levels of UCH-L1 in the observation group was significantly higher (2.28±1.21 vs. 0.81±0.39 ng/mL, P=0.000). Furthermore, at 6 hours after birth, the serum levels of UCH-L1 were significantly higher in neonates with moderate to severe HIE compared to patients with mild HIE (2.92±0.80 and 1.76±0.72 ng/mL, respectively, P=0.000). Pearson correlation analysis showed that the expression levels of UCH-L1 were negatively correlated with the development quotient (DQ), intelligence index (MI), and the Neonatal Behavioral Neurological Assessment (NBNA) score of HIE newborns (P<0.05).

CONCLUSIONS

The level of UCH-L1 protein expression is elevated in the serum of newborns with HIE, and this may have a certain clinical value in predicting the intelligence of children.

Cord blood S100B: reference ranges and interest for early identification of newborns with brain injury

Background Neurological complications are common in the premature and full-term neonates admitted to the intensive care unit, but the diagnosis of these complications is often difficult to make. S100B protein, measured in cord blood, may represent a valuable tool to better identify patients at risk of brain injury. Methods As a first step, we established S100B cord blood serum reference intervals from 183 preterm and 200 full-term neonates. We then measured cord blood serum S100B to identify neurological complications in 272 neonates hospitalized at the neonatal intensive care unit (NICU). Diagnosis of brain injury relied on imaging examination. Results The 95th percentiles of S100B concentration in cord blood were established as 1.21 μg/L for the 383 neonates, 0.96 μg/L for full-term neonates and 1.36 μg/L for premature neonates. Among the 272 neonates hospitalized at the NICU, 11 presented neurological complications. Using 1.27 μg/L as the optimal sensitivity/specificity threshold, S100B differentiate neonates with and without neurological complications with a sensitivity of 45.5% (95% confidence intervals [CI]: 16.7-76.6) and a specificity of 88.9% (95% CI: 84.4-92.4) (p = 0.006). In combination with arterial pH (<7.25), sensitivity increased to 90.9% (95% CI: 58.7-99.8), while specificity was 51.2% (95% CI: 44.8-57.7). The sensitivity is significantly (p = 0.03) increased in comparison to S100B alone. The specificity is significantly higher with S100B only than with pH + S100B (p < 0.001). Conclusions Cord blood S100B protein, in combination with arterial cord blood pH, has the potential to help clinicians to detect at birth neurological complications in neonates hospitalized in an NCIU.

Early predictors of perinatal brain damage: the role of neurobiomarkers

The early detection of perinatal brain damage in preterm and term newborns (i.e. intraventricular hemorrhage, periventricular leukomalacia and perinatal asphyxia) still constitute an unsolved issue. To date, despite technological improvement in standard perinatal monitoring procedures, decreasing the incidence of perinatal mortality, the perinatal morbidity pattern has a flat trend. Against this background, the measurement of brain constituents could be particularly useful in the early detection of cases at risk for short-/long-term brain injury. On this scenario, the main European and US international health-care institutions promoted perinatal clinical and experimental neuroprotection research projects aimed at validating and including a panel of biomarkers in the clinical guidelines. Although this is a promising attempt, there are several limitations that do not allow biomarkers to be included in standard monitoring procedures. The main limitations are: (i) the heterogeneity of neurological complications in the perinatal period, (ii) the small cohort sizes, (iii) the lack of multicenter investigations, (iv) the different techniques for neurobiomarkers assessment, (iv) the lack of consensus for the validation of assays in biological fluids such as urine and saliva, and (v), the lack of reference curves according to measurement technique and biological fluid. In the present review we offer an up-to-date overview of the most promising developments in the use of biomarkers in the perinatal period such as calcium binding proteins (S100B protein), vasoactive agents (adrenomedullin), brain biomarkers (activin A, neuron specific enolase, glial fibrillary acidic protein, ubiquitin carboxyl-terminal hydrolase-L1) and oxidative stress markers.

Vitamin D as an Adjuvant Therapy in Neonatal Hypoxia: Is it Beneficial?

Background

Neonatal hypoxic ischemic encephalopathy (HIE) is a potentially devastating disorder associated with significant mortality and long-term morbidity.

Objective

The aim of this study was to study the role of vitamin D as an adjuvant therapy for management of neonatal HIE.

Patients and Methods

This study was carried out on 60 neonates with HIE grade II who were diagnosed according to modified Sarnat staging and were divided in to 2 groups: Group I: Included 30 neonates with Sarnat grade II HIE who received single daily oral dose of vitamin D3 (1000 IU) for 2 weeks in addition to daily subcutaneous (SC) human recombinant erythropoietin (2500 IU/kg) for 5 days and IM or IV magnesium sulphate 250 mg/kg within half an hour of birth, and subsequently 125 mg/kg at 24 and 48 hours of life. Group II: Included 30 neonates with HIE grade II who received erythropoietin and magnesium sulphate as group I but without vitamin D. Two blood samples were taken from all neonates included in both groups; the 1^st at diagnosis and the 2^nd after 2 weeks of therapy. This study included also 30 healthy neonates as a control group. All neonates included in this study were subjected to: complete clinical examination with assessment of Apgar score at 5 and 10 minutes, measurement of arterial blood gases and serum 25 (OH) vitamin D, calcium, phosphorus, S100-B and IL-17 levels.

Results

Before therapy, there were no significant differences between group I and II in PH, PO2 and PCO2 (p= 0.294, 0.462, 0.758 respectively), but after 2 weeks of therapy, there were significantly higher PH levels in group I compared with group II (p <0.001) while there were no significant differences between group I and II regarding PO2 and PCO2. Before therapy, there were no significant differences in serum 25(OH) vitamin D levels between group I and II while there were significantly lower serum 25(OH) vitamin D levels in group I and II compared with controls (P1; comparison between group I and II = 0.742, P2; comparison between group I and controls = 0.001 and P3; comparison between group II and controls = 0. 001). There were no significant differences between group I and II and between group I and II and control as regard serum calcium (P1= 0.943, P2= 0.875 and P3= 0.764) and phosphorus (P1= 0.862, P2= 0.921, P3= 0.786). There were no significant differences between group I and II regarding serum IL-17 levels while there were significantly lower serum IL-17 levels in group I and II compared with controls (P1 = 0.457, P2 = 0.043 and P3 = 0.023). Before therapy, there were no significant differences in serum S100-B levels between group I and II while there were significantly higher serum S100-B levels in group I and II compared with control (P1 = 0.381, P2 = 0.001 and P3= 0.001) but after therapy, there were significantly higher S100-B levels in group II compared with group I and significantly higher S100-B levels in group I and II compared with control (P1= 0.001, P2= 0.043, P3 = 0.001). There were significant negative correlations in group I between serum S100-B and PH and between S100-B and serum vitamin D before and after therapy.

Conclusion

Vitamin D was found to improve the cases of group I as demonstrated by the reduction of serum S100-B levels after vitamin D therapy.

Recommendations

Extensive multicenter studies are required on a large number of patients with Sarnat grade II HIE with longer duration of follow up to give valid recommendations about the use of vitamin D as an adjuvant therapy in Sarnat grade II HIE.

Serum biomarkers of neuronal injury in newborns evaluated for selective head cooling: a comparative pilot study

Background Evaluation of newborns for hypoxic ischemic encephalopathy (HIE) includes laboratory and clinical parameters, as well as amplitude integrated electroencephalogram (aEEG). Based on qualifying criteria, selective head cooling (SHC) is initiated for infants with evidence of moderate to severe HIE. However, some newborns may not qualify for hypothermia therapy based on normal aEEG. Objective To compare levels of serum glial fibrillary acidic protein (GFAP), ubiquitin c-terminal hydrolase-1 (UCHL-1) protein and phosphorylated axonal neurofilament heavy chain (pNF-H), in newborns who met initial screening criteria for HIE but did not qualify for head cooling, to the levels in healthy newborns. Study design Newborns ≥36 weeks of gestational age at risk for HIE, who were evaluated but did not qualify for SHC from July 2013 through June 2014 at NYU Langone Medical Center and Bellevue Hospital center were enrolled. A control group included healthy newborns from the newborn nursery (NBN). Serum samples were collected between 24 and 48 h of life from both groups. Results There was no significant difference in the serum levels of GFAP, UCHL-1 protein and pNF-H between the two groups of infants. Conclusion Newborns at risk for HIE who met the initial criteria for head cooling but who were excluded based on normal aEEG did not show significant elevation of biomarkers of brain injury compared to healthy newborns. These findings may help to validate using aEEG as an additional evaluation criteria in cooling.

Protein S100B in umbilical cord blood as a potential biomarker of hypoxic-ischemic encephalopathy in asphyxiated newborns

BACKGROUND

Neonatal hypoxic ischemic encephalopathy (HIE) is a devastating condition resulting from a sustained lack of oxygen during birth. The interest in identifying a relevant biomarker of HIE has thrown into limelight the role of protein S100B as a clinical diagnostic marker of hypoxic brain damage in neonates.

AIMS

To evaluate the diagnostic value of protein S100B, measured in umbilical cord blood immediately after birth, as a useful biomarker in the diagnosis of HIE Sarnat stages II-III as well as a marker for long-term mortality and morbidity.

STUDY DESIGN

Protein S100B was analyzed in cord blood sampled at birth from 13 newborns later diagnosed with stage II-III HIE and compared with 21 healthy controls. S100B concentrations were related to cord artery pH, amplitude-integrated electroencephalography (aEEG), stage of HIE, and death/sequelae up to an age of 6years. Both parametric and non-parametric statistics were used with a two-sided P<0.05 considered significant.

RESULTS

The difference in S100B concentration was marginally statistically significant between HIE cases and controls (P=0.056). Cord blood acidosis (P=0.046), aEEG pattern severity (P=0.030), HIE severity (P=0.027), and condition at 6-year follow-up (healthy/permanent sequelae/death; P=0.027) were all related to an increase in S100B concentration.

CONCLUSIONS

Protein S100B in neonates suffering from HIE stages II-III appeared elevated in umbilical cord blood at birth. The S100B concentrations were positively associated to the severity of disease and the risk of suffering from neurodevelopmental sequelae and even death.

Preliminary case control study to establish the correlation between novel peroxidation biomarkers in cord serum and the severity of hypoxic ischemic encephalopathy

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) has deleterious neurological consequences. To identify patients at risk of neuronal damage deserving implementation of neuroprotective strategies clinicians have relied on prenatal sentinel events, postnatal clinical assessment (Apgar score), and blood gas analysis. This feasibility study aimed to assess if lipid peroxidation byproducts associated with neuronal damage correlated with cord blood metabolic acidemia in patients with HIE.

POPULATION AND METHODS

This is a case/control study in which cases were newborn infants with severe acidemia (pH<7.00; base excess ≥12mmol/L) while control babies exhibited normal gases (pH=7.20-7.40; base excess=-4 to +4mmol/L) in the first cord blood analysis performed immediately after birth. Concomitantly, lipid peroxidation byproducts were determined using ultra performance liquid chromatography coupled to mass spectrometry in the same cord blood sample.

RESULTS

A total of 19 controls and 20 cases were recruited. No differences in gestational characteristics were present. However, cases exhibited profound metabolic alterations as compared to controls (Cases vs.

CONTROL

pH=6.90±0.1 vs. 7.33±0.03; base excess=-15±3 vs. -1±2mmol/L), 85% were admitted to the NICU, and 50% developed symptoms of HIE. 8-iso-15(R)-PGF2α (P=0.01) and total isoprostanes (P=0.045) presented statistically significant differences between cases and control groups and correlated with level of HIE.

CONCLUSIONS

The 8-iso-15(R)-PGF2α and isoprostanes reflecting oxidative damage are significantly increased in severe postnatal acidemia. Follow up studies with adequate power are necessary to confirm if these biomarkers measured in cord blood serum could be predictive of neonatal encephalopathy.

Glial Fibrillary Acidic Protein Is Not an Early Marker of Injury in Perinatal Asphyxia and Hypoxic-Ischemic Encephalopathy

Brain-specific glial fibrillary acidic protein (GFAP) has been suggested as a potential biomarker for hypoxic ischemic encephalopathy (HIE) in newborns (1, 2). Previous studies have shown increased levels in post-natal blood samples. However, its ability to guide therapeutic intervention in HIE is unknown. Therapeutic hypothermia for HIE must be initiated within 6 h of birth, therefore a clinically useful marker of injury would have to be available immediately following delivery. The goal of our study was to examine the ability of GFAP to predict grade of encephalopathy and neurological outcome when measured in umbilical cord blood (UCB). Infants with suspected perinatal asphyxia (PA) and HIE were enrolled in a single, tertiary maternity hospital, where UCB was drawn, processed, and bio-banked at birth. Expression levels of GFAP were measured by ELISA. In total, 169 infants (83 controls, 56 PA, 30 HIE) were included in the study. GFAP levels were not increased in UCB of case infants (PA/HIE) when compared to healthy controls or when divided into specific grades of HIE. Additionally, no correlation was found between UCB levels of GFAP and outcome at 36 months.