Neural injury markers to predict neonatal complications in intrauterine growth restriction

Early changes in S100B maternal blood levels can predict fetal intrauterine growth restriction

OBJECTIVES

Intrauterine growth restriction (IUGR) represents one of the main causes of perinatal mortality and morbidity. Nowadays, IUGR early diagnosis is mandatory in order to limit the occurrence of multiorgan failure, especially the brain. Therefore, we investigated whether longitudinal S100B assessment in maternal blood could be a trustable predictor of IUGR.

METHODS

We conducted a prospective study in 480 pregnancies (IUGR: n=40; small for gestational age, SGA: n=40; controls: n=400) in whom S100B was measured at three predetermined monitoring time-points (T1: 8-18 GA; T2: 19-23 GA; T3: 24-28 GA).

RESULTS

Lower S100B in IUGR fetuses than SGA and controls (p<0.05, for all) at T1-T3. Receiver operating characteristic curve showed that S100B at T1 was the best predictor of IUGR (sensitivity: 100 %; specificity: 81.4 %) than T2, T3.

CONCLUSIONS

The early lower S100B concentration in pregnant women lately complicated by IUGR support the notion that non-invasive early IUGR diagnosis and monitoring is becoming feasible. Results open the way to further studies aimed at diagnosing and monitoring fetal/maternal diseases at earliest time.

Blood Biomarkers in the Fetally Growth Restricted and Small for Gestational Age Neonate: Associations with Brain Injury

Fetal growth restriction (FGR) and small for gestational age (SGA) infants have increased risk of mortality and morbidity. Although both FGR and SGA infants have low birthweights for gestational age, a diagnosis of FGR also requires assessments of umbilical artery Doppler, physiological determinants, neonatal features of malnutrition, and in utero growth retardation. Both FGR and SGA are associated with adverse neurodevelopmental outcomes ranging from learning and behavioral difficulties to cerebral palsy. Up to 50% of FGR, newborns are not diagnosed until around the time of birth, yet this diagnosis lacks further indication of the risk of brain injury or adverse neurodevelopmental outcomes. Blood biomarkers may be a promising tool. Defining blood biomarkers indicating an infant's risk of brain injury would provide the opportunity for early detection and therefore earlier support. The aim of this review was to summarize the current literature to assist in guiding the future direction for the early detection of adverse brain outcomes in FGR and SGA neonates. The studies investigated potential diagnostic blood biomarkers from cord and neonatal blood or serum from FGR and SGA human neonates. Results were often conflicting with heterogeneity common in the biomarkers examined, timepoints, gestational age, and definitions of FGR and SGA used. Due to these variations, it was difficult to draw strong conclusions from the results. The search for blood biomarkers of brain injury in FGR and SGA neonates should continue as early detection and intervention is critical to improve outcomes for these neonates.

Brain Damage in Preterm and Full-Term Neonates: Serum Biomarkers for the Early Diagnosis and Intervention

The Brain is vulnerable to numerous insults that can act in the pre-, peri-, and post-natal period. There is growing evidence that demonstrate how oxidative stress (OS) could represent the final common pathway of all these insults. Fetuses and newborns are particularly vulnerable to OS due to their inability to active the antioxidant defenses. Specific molecules involved in OS could be measured in biologic fluids as early biomarkers of neonatal brain injury with an essential role in neuroprotection. Although S-100B seems to be the most studied biomarker, its use in clinical practice is limited by the complexity of brain damage etiopathogenesis and the time of blood sampling in relation to the brain injury. Reliable early specific serum markers are currently lacking in clinical practice. It is essential to determine if there are specific biomarkers that can help caregivers to monitor the progression of the disease in order to active an early neuroprotective strategy. We aimed to describe, in an educational review, the actual evidence on serum biomarkers for the early identification of newborns at a high risk of neurological diseases. To move the biomarkers from the bench to the bedside, the assays must be not only be of a high sensitivity but suitable for the very rapid processing and return of the results for the clinical practice to act on. For the best prognosis, more studies should focus on the association of these biomarkers to the type and severity of perinatal brain damage.

Molecular Indicators of Blood-Brain Barrier Breakdown and Neuronal Injury in Pregnancy Complicated by Fetal Growth Restriction

This study evaluated the damage to the endothelial tight junctions (TJs) in pregnancies complicated by fetal growth restriction (FGR) and investigated whether FGR is related to blood-brain barrier disintegration and, subsequently, to the appearance of proteins indicative of neuronal injury in maternal blood. The studied group included 90 pregnant women diagnosed with FGR. The control group consisted of 70 women with an uncomplicated pregnancy. The biochemical measurements included serum neuronal proteins (subunit of the N-methyl-D-aspartate receptor-NR1, nucleoside diphosphate kinase A-NME1, and S100 calcium-binding protein B-S100B), serum TJ proteins (occludin-OCLN, claudin-5-CLN5, zonula occludens-zo-1, and OCLN/zo-1 and CLN5/zo-1 ratios), and placental expression of TJ proteins (OCLN, claudin-4 CLN4, CLN5, zo-1). The significantly higher serum S100B and CLN5 levels and serum CLN5/zo-1 ratio were observed in FGR compared to healthy pregnancies. Moreover, FGR was characterized by increased placental CLN5 expression. Both serum NME1 levels and placental CLN4 expression in FGR pregnancies were significantly related to the incidence of neurological disorders in newborns. Mothers of FGR neonates who developed neurological complications and intraventricular hemorrhage (IVH) had statistically higher NME1 concentrations during pregnancy and significantly lower placental CLN4 expression than mothers of FGR neonates without neurological abnormalities. The serum NME1 levels and placental CLN4 expression were predictive markers of IVH in the FGR group. The blood-brain barrier is destabilized in pregnancies complicated by FGR. Neurological disorders, including IVH, are associated with higher serum concentrations of NME1 and the decreased placental expression of CLN4. The serum NME1 levels and placental CLN4 expression may serve as biomarkers, helpful in predicting IVH in FGR. It may allow for more precise monitoring and influence decision-making on the optimal delivery time to avoid developing neurological complications.

[Research advances in the biomarkers of brain damage in preterm infants]

While the survival rate of preterm infants has continually increased with the development of perinatal and neonatal monitoring techniques, the incidence of brain injury in preterm infants has been increasing, resulting in varying degrees of cognitive impairment and movement disorders. Measuring the biomarkers of brain damage is an important means to diagnose brain injury. The biomarkers can be divided into neuroglial damage markers, neuronal damage markers and other markers according to the features of injured cells. The biomarkers widely used in clinical practice include S100B protein, myelin basic protein and neuron-specific enolase. Recent studies have newly discovered a collection of markers that can suggest potential brain injury in preterm infants, such as glial fibrillary acidic protein, neurofilament light chain protein, α-II spectrin breakdown products, chemokines, melatonin and urinary metabolomics. These biomarkers can contribute to the early diagnosis and treatment of preterm brain injury, essential for improving neural development and prognosis. This article reviews the latest research advances in the biomarkers of preterm brain injury, in order to provide evidence for the early diagnosis and treatment of this condition.

Neural and cardiac injury markers in fetal growth restriction and their relation to perinatal outcomes

Objective:

To compare the levels of umbilical cord blood Neuron-Specific Enolase (NSE) and troponin T and venous blood gas samples between healthy newborns and growth-retarded fetuses with impaired Doppler velocity or low APGAR scores.

Materials and Methods:

This study was a prospective cohort study. The study group comprised 26 patients with intrauterine growth restriction and pathologic Doppler symptoms, and the control group included 24 healthy fetuses. Umbilical cord blood and blood gas samples were taken from all patients. The blood samples were centrifuged and sent to a laboratory to study NSE and troponin T Perinatal outcomes were evaluated from the medical records of the newborns.

Results:

Both groups were similar in terms of demographic characteristics. Fetuses with fetal growth restriction (FGR) were born earlier and had lower APGAR scores than the study group. Chronic hypoxemic fetuses in the study group had lower cord pH and HCO₃ levels. Further, troponin T levels were higher in the study group than in the control group. There were no major differences in Doppler velocity measurements.

Conclusion:

It has been understood that cardiac and neuronal injury detection on fetuses with FGR, troponin T, and NSE are indicators that can be used. In the literature there are studies with heterogeneous paradigms using different indicators to find neuronal injury. As a result of this study, it is clear that to assess neonatal prognosis, wider-scoped and comparative studies will provide more information about the subject.

Therapeutic potential to reduce brain injury in growth restricted newborns

Brain injury in intrauterine growth restricted (IUGR) infants is a major contributing factor to morbidity and mortality worldwide. Adverse outcomes range from mild learning difficulties, to attention difficulties, neurobehavioral issues, cerebral palsy, epilepsy, and other cognitive and psychiatric disorders. While the use of medication to ameliorate neurological deficits in IUGR neonates has been identified as warranting urgent research for several years, few trials have been reported. This review summarises clinical trials focusing on brain protection in the IUGR newborn as well as therapeutic interventions trialled in animal models of IUGR. Therapeutically targeting mechanisms of brain injury in the IUGR neonate is fundamental to improving long-term neurodevelopmental outcomes. Inflammation is a key mechanism in neonatal brain injury; and therefore an appealing target. Ibuprofen, an anti-inflammatory drug currently used in the preterm neonate, may be a potential therapeutic candidate to treat brain injury in the IUGR neonate. To better understand the potential of ibuprofen and other therapeutic agents to be neuroprotective in the IUGR neonate, long-term follow-up information of neurodevelopmental outcomes must be studied. Where agents such as ibuprofen are shown to be effective, have a good safety profile and are relatively inexpensive, they can be widely adopted and lead to improved outcomes.

Associations between neural injury markers of intrauterine growth-restricted infants and neurodevelopment at 2 years of age

Objectives: The aim of this study was to evaluate the relationships between brain injury biomarkers in intrauterine growth-restricted (IUGR) infants (S100B and neuron-specific enolase (NSE)) and neurodevelopment at 2 years of age. Methods: This prospective case-control study was a cooperative effort among Spanish Maternal and Child Health Network (Retic SAMID) hospitals. At inclusion, biometry for estimated fetal weight and feto-placental Doppler variables were measured for each infant. Maternal venous blood and fetal umbilical arterial blood samples were collected at the time of delivery and neural injury markers S100B and NSE concentrations were measured. Neurodevelopment was evaluated at 2 years of age using the Bayley Scales of Infant and Toddler Development, third edition (Bayley-III). Results: Fifty six pregnancies were included. Thirty-one infants were classified as IUGR and 25 as non-IUGR. Neurodevelopmental evaluation at 2 years of age indicated that there were no between-group differences for any of the tests. For all patients in both groups, we found statistically significant inverse relationships between the concentrations of NSE in the cord blood and the results of the cognitive test (r = -271, p = .042), fine motor subtest (r = -280, p = .036), and social-emotional test (r = -349, p = .015). We also found statistically significant differences between the concentrations of S100B in the cord blood and the results of the cognitive test (r = -306, p = .022) and expressive communication subtest (r = -304, p = .023). For the IUGR group, we found a significant inverse relationship between the concentrations of S100B in the maternal serum and the results of adaptive behavior test (p < .05). In the non-IUGR group, we found statistically significant inverse relationships between the concentration of NSE in the cord blood and the results of the fine motor subtest (r = -446, p = .025) and social-emotional test (r = -489, p = .021). The difference between the concentration of S100B in the cord blood and the language composite score was also statistically significant (p = .038). Conclusions: At 2 years of age, the concentrations of NSE and S100B were higher in the non-IUGR and IUGR groups with the worst scores for some areas of neurodevelopmental evaluation. The value of these biomarkers for prognostic neurodevelopmental use requires further investigation for both non-IUGR and IUGR infants.

Neural injury markers in intrauterine growth restriction and their relation to perinatal outcomes

BACKGROUNDThe aims of this study were to (i) compare the concentrations of two neural injury markers, S100B protein and neuron-specific enolase (NSE), in intrauterine growth-restricted (IUGR) fetuses and in fetuses with appropriate growth-for-gestational-age (AGA), and (ii) investigate potential relationships between concentrations of these markers, Doppler abnormalities, and adverse perinatal or neonatal outcomes.METHODSThis was a case-controlled, cooperative, prospective study among Spanish Maternal and Child Health Network (Retic SAMID) hospitals. At inclusion, biometry for estimated fetal weight and feto-placental Doppler were measured. At the time of delivery, maternal venous blood and fetal umbilical arterial blood samples were collected. S100B and NSE concentrations were determined from these samples.RESULTSIn total, 254 pregnancies were included. Among these, 147 were classified as IUGR and 107 as AGA. There were no differences between the groups in S100B concentrations. However, levels of NSE in maternal and umbilical cord serum differed significantly between these groups (2.31 in AGA vs. 2.51 in IUGR in (P<0.05); and 2.89 in AGA vs. 3.25 in IUGR (P<0.05), respectively). No differences were observed in these neurological markers when stratified by perinatal or neonatal complications.CONCLUSIONAlthough some variations exist in these neurological markers, they did not correlate with perinatal or neonatal complications.