Biomarkers of hepatic injury and function in neonatal hypoxic ischemic encephalopathy and with therapeutic hypothermia

How do we reach the goal of personalized medicine for neuroprotection in neonatal hypoxic-ischemic encephalopathy?

Therapeutic hypothermia is now standard of care for neonates with hypoxic-ischemic encephalopathy (HIE) in high income countries (HIC). Conversely, compelling trial evidence suggests that hypothermia is ineffective, and may be deleterious, in low- and middle-income countries (LMIC), likely reflecting the lower proportion of infants who had sentinel events at birth, suggesting that injury had advanced to a stage when hypothermia is no longer effective. Although hypothermia significantly reduced the risk of death and disability in HICs, many infants survived with disability and in principle may benefit from targeted add-on neuroprotective or neurorestorative therapies. The present review will assess biomarkers that could be used to personalize treatment for babies with HIE - to determine first whether an individual infant is likely to respond to hypothermia, and second, whether additional treatments may be beneficial.

Oligodendrocyte progenitor cells' fate after neonatal asphyxia-Puzzling implications for the development of hypoxic-ischemic encephalopathy

Premature birth or complications during labor can cause temporary disruption of cerebral blood flow, often followed by long-term disturbances in brain development called hypoxic-ischemic (HI) encephalopathy. Diffuse damage to the white matter is the most frequently detected pathology in this condition. We hypothesized that oligodendrocyte progenitor cell (OPC) differentiation disturbed by mild neonatal asphyxia may affect the viability, maturation, and physiological functioning of oligodendrocytes. To address this issue, we studied the effect of temporal HI in the in vivo model in P7 rats with magnetic resonance imaging (MRI), microscopy techniques and biochemical analyses. Moreover, we recreated the injury in vitro performing the procedure of oxygen-glucose deprivation on rat neonatal OPCs to determine its effect on cell viability, proliferation, and differentiation. In the in vivo model, MRI evaluation revealed changes in the volume of different brain regions, as well as changes in the directional diffusivity of water in brain tissue that may suggest pathological changes to myelinated neuronal fibers. Hypomyelination was observed in the cortex, striatum, and CA3 region of the hippocampus. Severe changes to myelin ultrastructure were observed, including delamination of myelin sheets. Interestingly, shortly after the injury, an increase in oligodendrocyte proliferation was observed, followed by an overproduction of myelin proteins 4 weeks after HI. Results verified with the in vitro model indicate, that in the first days after damage, OPCs do not show reduced viability, intensively proliferate, and overexpress myelin proteins and oligodendrocyte-specific transcription factors. In conclusion, despite the increase in oligodendrocyte proliferation and myelin protein expression after HI, the production of functional myelin sheaths in brain tissue is impaired. Presented study provides a detailed description of oligodendrocyte pathophysiology developed in an effect of HI injury, resulting in an altered CNS myelination. The described models may serve as useful tools for searching and testing effective of effective myelination-supporting therapies for HI injuries.

Unconjugated bilirubin is correlated with the severeness and neurodevelopmental outcomes in neonatal hypoxic-ischemic encephalopathy

Unconjugated bilirubin (UB) levels during the first week after birth are related to outcomes in neonatal hypoxic-ischemic encephalopathy (HIE). Clinical Sarnat staging of HIE, brain magnetic resonance imaging (MRI), hearing outcomes, and neurodevelopmental outcomes ≥ 1 year were used to correlate UB in 82 HIE patients. The initial UB level was significantly correlated with lactic acid levels. The peak UB was higher (p < 0.001) in stage I (10.13 ± 4.03 mg/dL, n = 34) than in stages II and III (6.11 ± 2.88 mg/dL, n = 48). Among the 48 patients receiving hypothermia treatment, a higher peak UB was significantly (p < 0.001) correlated with unremarkable brain MRI scans and unremarkable neurodevelopmental outcomes at age ≥ 1 year. The peak UB were higher (P = 0.015) in patients free of seizures until 1 year of age (6.63 ± 2.91 mg/dL) than in patients with seizures (4.17 ± 1.77 mg/dL). Regarding hearing outcomes, there were no significant differences between patients with and without hearing loss. The UB level in the first week after birth is an important biomarker for clinical staging, MRI findings, seizures after discharge before 1 year of age, and neurodevelopmental outcomes at ≥ 1 year of age.

Cerebral Tissue Oxygen Saturation Measurements in Perinatal Asphyxia Cases Treated with Therapeutic Hypothermia

Cerebral tissue oxygen saturation (CrSO2) measured with near-infrared spectroscopy (NIRS) technology has recently become the subject of several research studies. The aim of this study was to investigate the diagnostic value of CrSO2 measurements in perinatal asphyxia (PA) cases. The study included a patient group of 42 PA cases, who were to be applied with therapeutic hypothermia (TH), and a control group of 42 healthy term newborns. PA cases were determined as moderate or severe encephalopathy (Sarnat score stage II or III) in clinical evaluation. In both groups, left (CrSO2L) and right (CrSO2R) NIRS measurements were taken for 10 minutes on the scalp. The arithmetic mean value of measurements was calculated and compared. The mean measurements were CrSO2R 67.38 ± 9.39 and CrSO2L 66.73 ± 7.76 in the patient group, and CrSO2R 80.28 ± 8.04 and CrSO2L 79.14 ± 8.49 in the control group. The mean CrSO2R and CrSO2L measurements of the patient group were statistically significantly lower than those of the control group (p < 0.001). In the Pearson correlation analysis, a significant correlation was determined in the patient group between cord blood gas pH and CrSO2R (r: 0.539, p < 0.001) and CrSO2L (r: 0.54, p < 0.001). For a cutoff value of CrSO2L ≤ 72%, the positive predictive value was 80 and the negative predictive value was 84.6. For a cutoff value of CrSO2R ≤ 74%, the positive predictive value was 79.5 and the negative predictive value was 82.5. Low CrSO2 measurements obtained with the NIRS method in PA cases to be applied with TH together with cord blood gas parameters can be considered a helpful parameter in diagnosis.

Adverse short- and long-term outcomes among infants with mild neonatal encephalopathy

BACKGROUND

Studies in newborns with mild neonatal encephalopathy (mNE) demonstrated normal outcomes, but recent literature suggests otherwise.

METHODS

This retrospective cohort study examined inborn infants between 2014 and 2017. Biochemical and clinical characteristics determined the presence of NE and an encephalopathy score categorized infants as Definite or Possible mNE. An Unexposed control group consisted of newborns not meeting the inclusion criteria. Long-term outcomes assessed included cerebral palsy, seizures, developmental disorder, and motor and speech delay. The association of mNE with seizure disorder by 3 years of age was assessed with logistic regression and developmental disorders with Cox proportional hazards models.

RESULTS

Of the 156,501 births, we identified 130 with Definite mNE and 445 with Possible mNE (0.8 and 2.8 per 1000 births, respectively). Both groups had significantly higher rates of any developmental disorder and motor and speech delay when compared to the Unexposed (p < 0.05, except for p = 0.07 for motor delay in the Possible NE group). The Definite mNE group had higher rates of developmental disorder and motor and speech delay when compared to the Unexposed with hazard ratios (95% CI) 2.0 (1.2-3.2), 3.7 (1.5-8.8), and 2.1 (1.3-3.5), respectively.

CONCLUSIONS

An estimate of short- and long-term consequences of mNE suggests that there may be a higher risk of adverse outcome.

IMPACT

Infants with mild NE are at significant risk for adverse short- and long-term outcomes. The risk of having an abnormal long-term outcome at 3 years of age were doubled in the mild NE group compared to the Unexposed group. Randomized clinical trials are needed as neuroprotective strategies may mitigate these.

Pharmacokinetics during therapeutic hypothermia in neonates: from pathophysiology to translational knowledge and physiologically-based pharmacokinetic (PBPK) modeling

INTRODUCTION

Perinatal asphyxia (PA) still causes significant morbidity and mortality. Therapeutic hypothermia (TH) is the only effective therapy for neonates with moderate to severe hypoxic-ischemic encephalopathy after PA. These neonates need additional pharmacotherapy, and both PA and TH may impact physiology and, consequently, pharmacokinetics (PK) and pharmacodynamics (PD).

AREAS COVERED

This review provides an overview of the available knowledge in PubMed (until November 2022) on the pathophysiology of neonates with PA/TH. In vivo pig models for this setting enable distinguishing the effect of PA versus TH on PK and translating this effect to human neonates. Available asphyxia pig models and methodological considerations are described. A summary of human neonatal PK of supportive pharmacotherapy to improve neurodevelopmental outcomes is provided.

EXPERT OPINION

To support drug development for this population, knowledge from clinical observations (PK data, real-world data on physiology), preclinical (in vitro and in vivo (minipig)) data, and molecular and cellular biology insights can be integrated into a predictive physiologically-based PK (PBPK) framework, as illustrated by the I-PREDICT project (Innovative physiology-based pharmacokinetic model to predict drug exposure in neonates undergoing cooling therapy). Current knowledge, challenges, and expert opinion on the future directions of this research topic are provided.

Patterns of acute kidney and hepatic injury and association with adverse outcomes in infants undergoing therapeutic hypothermia for hypoxic ischemic encephalopathy

OBJECTIVE

To describe patterns of renal and hepatic injury in infants with hypoxic ischemic encephalopathy (HIE).

STUDY DESIGN

Retrospective cohort of infants receiving therapeutic hypothermia for HIE was classified into groups based on organ injury: neither acute kidney injury (AKI) nor acute hepatic injury (AHI), isolated AKI, isolated AHI, or both AKI/AHI. Biomarkers and outcomes were described and analyzed.

RESULTS

Among 188 infants, 55% had no AKI nor AHI, 7% had only AKI, 22% had only AHI and 16% had both AKI and AHI. Infants with both AKI/AHI had the highest mortality (47%) and worse outcomes, compared to other injury groups, although AKI/AHI was not significantly associated with mortality (hazard ratio 2.5; 95% CI 0.9-6.9), after accounting for severity of HIE. For surviving infants, biomarkers of organ injury, on average, normalized by discharge.

CONCLUSION

Infants with HIE with both AKI/AHI have worse outcomes than infants with AKI or AHI alone.

Effect of Therapeutic Hypothermia Treatment on Acute Phase Reactants

Objective In our study, we aimed to examine the effect of therapeutic hypothermia treatment on C-reactive protein (CRP) and interleukin-6 (IL-6) in infants with hypoxic ischemic encephalopathy (HIE).

Methods The data of the patients with the diagnosis of HIE we followed up in our unit between 2017 and 2018 were analyzed retrospectively. Patients who died during follow-up and patients with proven septicemia at the time of examination were excluded from the study. The routine CRP and IL-6 values ​​of the patients included in the study were compared before and after hypothermia treatment.

Results Therapeutic hypothermia treatment applied for 72 hours was found to cause a statistically significant increase in CRP after treatment when compared with the values ​​measured before treatment (0.6 (0.2–1.9) before and median (P25–75), and after treatment 7.5 (4–18) and median (P25–75) mg/L, p=0.00). While IL-6 was found to be high in the early period due to the effect of hypoxia, it was found to be low after hypothermia treatment (80.5 (40–200) median (P25–75) – 32 (18–50) median (P25–75) pg/ml, p=0.131). While the white blood cell count was high before hypothermia treatment due to hypoxia, it was found to be low after treatment (24600 (19600–30100) median (P25–75) –11300 (8800–14200) median (P25–75)/µL, p=0.001).

Conclusion White blood cells and IL-6 can be found to be high due to hypoxia without infection, and CRP can be found to be high after therapeutic hypothermia treatment without infection. The effect of hypoxia and hypothermia should be considered when evaluating acute phase reactants.

Noninfectious influencers of early-onset sepsis biomarkers

Diagnostic tests for sepsis aim to either detect the infectious agent (such as microbiological cultures) or detect host markers that commonly change in response to an infection (such as C-reactive protein). The latter category of tests has advantages compared to culture-based methods, including a quick turnaround time and in some cases lower requirements for blood samples. They also provide information on the immune response of the host, a critical determinant of clinical outcome. However, they do not always differentiate nonspecific host inflammation from true infection and can inadvertently lead to antibiotic overuse. Multiple noninfectious conditions unique to neonates in the first days after birth can lead to inflammatory marker profiles that mimic those seen among infected infants. Our goal was to review noninfectious conditions and patient characteristics that alter host inflammatory markers commonly used for the diagnosis of early-onset sepsis. Recognizing these conditions can focus the use of biomarkers on patients most likely to benefit while avoiding scenarios that promote false positives. We highlight approaches that may improve biomarker performance and emphasize the need to use patient outcomes, in addition to conventional diagnostic performance analysis, to establish clinical utility.

Lipid Profiles from Dried Blood Spots Reveal Lipidomic Signatures of Newborns Undergoing Mild Therapeutic Hypothermia after Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is associated with perinatal brain injury, which may lead to disability or death. As the brain is a lipid-rich organ, various lipid species can be significantly impacted by HIE and these correlate with specific changes to the lipidomic profile in the circulation. Objective: To investigate the peripheral blood lipidomic signature in dried blood spots (DBS) from newborns with HIE. Using univariate analysis, multivariate analysis and sPLS-DA modelling, we show that newborns with moderate-severe HIE (n = 46) who underwent therapeutic hypothermia (TH) displayed a robust peripheral blood lipidomic signature comprising 29 lipid species in four lipid classes; namely phosphatidylcholine (PC), lysophosphatidylcholine (LPC), triglyceride (TG) and sphingomyelin (SM) when compared with newborns with mild HIE (n = 18). In sPLS-DA modelling, the three most discriminant lipid species were TG 50:3, TG 54:5, and PC 36:5. We report a reduction in plasma TG and SM and an increase in plasma PC and LPC species during the course of TH in newborns with moderate-severe HIE, compared to a single specimen from newborns with mild HIE. These findings may guide the research in nutrition-based intervention strategies after HIE in synergy with TH to enhance neuroprotection.

The Term Newborn: Evaluation for Hypoxic-Ischemic Encephalopathy

Neonatal encephalopathy due to perinatal hypoxia-ischemia (hypoxic-ischemic encephalopathy [HIE]) occurs at a rate of 1 to 3 per 1000 live births. Therapeutic hypothermia is the standard of care and the only currently available therapy to reduce the risk of death or disability in newborns with moderate to severe HIE. Hypothermia therapy needs to be initiated within 6 hours after birth in order to provide the best chance for neuroprotection. All pediatricians and delivery room attendants should be trained to recognize encephalopathy and understand the eligibility criteria for treatment. The modified Sarnat examination is the most frequently used tool to assess the degree of encephalopathy and has six categories, each of which can have mild, moderate, severe abnormalities. Apart from historical and biochemical criteria, a neonate must have 3 of 6 categories scored in the moderate or severe range in order to qualify for hypothermia as was done in the randomized trials. Whether an infant qualifies or there is concern that an infant might have HIE, transfer to a center that can perform treatment should be initiated immediately. Hypothermia significantly reduces the risk of death or moderate to severe impairments at 2 years and at school age. On average, only 7 neonates need to be treated for one neonate to benefit. Although easy in concept, implementation of hypothermia does require expertise and should be carried out under the guidance of a neonatologist. If infants are passively cooled prior to transport, core temperature needs to be closely monitored with a target of 33.5°C ± 0.5°C. Maintenance of homeostasis is important in order to prevent conditions that may result in additional brain injury. Seizures are common in neonates with HIE, but electrographic seizures are rare in the first few hours after birth if the insult occurred during labor and delivery. Prophylactic antiepileptic drugs should not be administered. Brain monitoring in the form of electroencephalogram (EEG) and or amplitude-integrated EEG should be implemented as soon as possible to help with prognosis and to accurately diagnose seizures.

Thermal Index for early non-invasive assessment of brain injury in newborns treated with therapeutic hypothermia: preliminary report

Perinatal asphyxia (PA) is the 3rd most common cause of neonatal death and one of the most common causes of severe neurological impairments in children. Current tools and measurements mainly based on the analysis of clinical evaluation and laboratory and electrophysiological tests do not give consistent data allowing to predict the severity of hypoxic-ischemic encephalopathy (HIE) until a magnetic resonance imaging (MRI) score is performed. The aim of this work is to evaluate the usefulness of the new index, called Thermal Index (TI) in the assessment of the degree of brain damage in newborns in the course of therapeutic hypothermia (TH) due to PA. This was a prospective, observational, pilot study which did not require any changes in the applicable procedures. Analysis has been applied to six newborn babies treated with TH in Neonatal/Paediatric ICU in University Hospital in Opole in 2018 due to PA. They all met criteria for TH according to the current recommendations. Brain MRI was performed after the end of TH when the children were brought back to normal temperature, with the use of a 1.5 T scanner, using T1-, T2-weighted images, fluid-attenuated inversion recovery (FLAIR), inversion recovery (IR), susceptibility-weighted imaging (SWI), and diffusion-weighted imaging (DWI). The images were assessed using MRI score according to the scoring system proposed by Weeke et al. The Thermal Index assessing endogenous heat production was calculated according to the formula proposed in this paper. A high, statistically significant positive correlation was found between MRI scores and TI values (0.98; p = 0.0003) in the 1st hour of therapy. High correlation with MRI assessment, the non-invasiveness of measurements and the availability of results within the first few hours of treatment, allow authors to propose the Thermal Index as a tool for early evaluating of the brain injury in newborns treated with TH. Further research is required to confirm the usefulness of the proposed method.

Dose-Related Adverse Drug Events in Neonates: Recognition and Assessment

The efficacy and safety of a drug is dose or exposure related, and both are used to assess the benefit-risk balance of a given drug and ultimately to decide on the specific drug license, including its dose and indication(s). Unfortunately, both efficacy and safety are much more difficult to establish in neonates, resulting in very few drugs licensed for use in this vulnerable population. This review will focus on dose-related adverse events in neonates. Besides the regulatory classification on seriousness, adverse event assessment includes aspects related to signal detection, causality, and severity. Disentangling confounders from truly dose-related adverse drug events remains a major challenge, as illustrated for drug-induced renal impairment, drug-induced liver injury, and neurodevelopmental outcome. Causality assessment, using either routine tools (Naranjo algorithm, World Health Organization's Uppsala Monitoring Center causality tool) or a Naranjo algorithm tailored to neonates, still does not sufficiently and reliably document causality in neonates. Finally, very recently, a first neonatal severity-grading tool for neonates has been developed. Following the development of advanced pharmacokinetic approaches and techniques to predict and assess drug exposure, additional efforts are needed to truly and fully assess dose adverse drug events. To further operationalize the recently developed tools on causality and severity, reference databases on a palette of biomarkers and outcome variables and their covariates are an obvious next step. These databases should subsequently be integrated in modeling efforts to truly explore safety outcome, including aspects associated with or caused by drug dose or exposure.

Does saffron supplementation have favorable effects on liver function indicators? A systematic review and meta-analysis of randomized controlled trials

Several pharmaceutical and non-pharmaceutical approaches have been suggested to improve liver health. There is a large discrepancy in the effects of saffron supplementation on liver function in adults. To fill this knowledge gap, this systematic review and meta-analysis of randomized controlled trials (RCTs) assess the effects of saffron supplementation on liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP). A systematic search current to August 2020 was performed in PubMed/Medline, Scopus, Web of Science, and Google Scholar using relevant keywords to detect eligible articles. A random-effects model was used to estimate the weighted mean difference (WMD) and 95% confidence (95% CI). Nine eligible trials were included in the final analysis. The pooled analysis revealed that serum ALT concentrations were significantly reduced using saffron compared to placebo (WMD: -2.39 U/L; 95% CI: -4.57 to -0.22; P = 0.03, I²= 87.9%, P < 0.001). However, saffron supplementation did not affect levels of serum AST (WMD: 1.12 U/L; 95% CI: -1.42 to 3.65; P = 0.39) or ALP (WMD: 4.32 U/L; 95% CI: -6.91 to 15.54; P = 0.78). In the dose-response analysis, we did not find a significant dose-response relationship between dosage and duration of saffron supplementation on serum levels of ALT, AST, and ALP. We found that saffron supplementation can reduce ALT serum concentrations without significant effects on other liver function indicators, including AST and ALP. Nevertheless, future large RCTs on diverse populations are needed to understand better the effects of saffron and its constituents on these enzymes.

Hepatic Injury in Neonates with Perinatal Asphyxia

Background: Perinatal asphyxia (PA) is a major cause of morbidity and mortality in which dramatic transient impairment in liver functions occurs in some patients. Objectives: We aimed to evaluate the state of the liver in cases of Perinatal asphyxia and to assess the severity of hepatic impairment in relation to different grades of HIE. Patients and Methods: This case-control study was conducted on 100 full-term newborns with perinatal asphyxia (Group I) and 50 healthy neonates served as controls (Group II). All biochemical parameters of liver function were measured on the 1st, 3rd, and 10th day after birth. These parameters include serum alanine transferase (ALT), aspartate transferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), total protein, serum albumin, serum bilirubin (total and direct), and international normalized ratio (INR), in both cases and controls. Results: Among babies with PA, 25 (25%) had an Apgar score of 0 to 3 (severe PA), 43 (43%) had an Apgar score of 4 to 5 (moderate PA) and 32 (32%) had an Apgar score of 6 to 7 (mild PA) at 5 minutes of life. HIE was found in 39% among cases of PA and the remaining 61% were normal. Among babies with PA and HIE; 25.7% had stage I, 41% had stage II and 33.3% had stage III. Impaired liver function was reported in 48% of asphyxiated babies. On the first day of life, ALT, AST, ALP, LDH, PT, and INR were significantly higher in Group I compared to Group II. However, total protein and serum albumin were significantly lower in Group I compared to Group II. ALT and AST showed a positive correlation with the severity of HIE. On the third day of life, LDH rises as the stage of HIE progressed from stage 0 to stage 3. The difference in LDH among most stages of HIE was statistically significant. Conclusion: Liver enzymes can be used as an easy early diagnostic marker to differentiate between babies with asphyxia and those without asphyxia. Also, liver enzymes can be used for the detection of the severity of PA.

Association of Routinely Measured Proinflammatory Biomarkers With Abnormal MRI Findings in Asphyxiated Neonates Undergoing Therapeutic Hypothermia

Background: The neuroprotective treatment effect of therapeutic hypothermia (TH) following perinatal asphyxia may be negatively influenced by neonatal sepsis and concomitant inflammation. We aimed to correlate routinely used blood biomarkers for perinatal sepsis in cooled asphyxiated newborns with MRI findings. Methods: Perinatal data was retrospectively collected from 67 cooled asphyxiated newborns. Levels of C-reactive protein (CRP), white blood cells and platelets were analyzed before, during and after TH. Interleukin-6 blood levels were analyzed before initiation of TH. Magnetic resonance imaging (MRI) on postnatal day 5-7 was used defining short-term outcome. Adverse outcome was defined as death or adverse MRI findings. Amplitude-integrated electroencephalography (aEEG) was additionally analyzed and correlated with short-term MRI outcome. Results: Forty-nine newborns had favorable short-term MRI outcome. Perinatal data referring to perinatal sepsis did not differ significantly between groups. IL-6 levels before initiation of TH and CRP levels on day three and after TH were significantly higher in newborns with adverse short-term MRI outcome. Males with adverse short-term MRI outcome had significantly increased CRP values at the end of the cooling phase. aEEG strongly correlated with short-term MRI outcome. Conclusion: Routinely used blood biomarkers may be helpful early identifying newborns at high risk of unfavorable outcome and in need of close neurodevelopmental follow-up.

Investigation of myocardial protection during pediatric CPB: Practical experience in 100 Chinese hospitals

Many measures have been proposed for myocardial protection in pediatric congenital heart surgeries, but little data is available for China. This study investigates myocardial protection strategies in pediatric cardiopulmonary bypass (CPB) throughout China. Online questionnaires were delivered to 100 hospitals in 27 provinces. The number of yearly on-pump pediatric cardiovascular surgeries in these hospitals varied greatly. About 91.0% of respondents believe that each surgery should have at least two perfusionists, while only 64.0% of hospitals actually met this requirement. For pediatric patients, crystalloid cardioplegia was more prevalent than blood-based cardioplegia. Histidine-tryptophan-ketoglutarate solution and St. Thomas crystalloid solution were dominant among crystalloid cardioplegia. Del Nido cardioplegia and St. Thomas blood-based cardioplegia ranked the top two in the popularity of blood-based cardioplegia. Dosages varied among different kinds of cardioplegia. In the choice of different cardioplegia, perfusionists mainly focused on myocardial protective effect and cost. Hypothermia of cardioplegia solution was maintained by ice buckets in 3/4 of the hospitals in this survey. In conclusion, the essence of myocardial protection management during pediatric CPB was cardiac arrest induced by cardioplegia under systemic hypothermia. However, there is no uniform standard for the type of cardioplegia, or dosages. Therefore, well-designed multicenter randomized controlled trials are warranted to provide tangible evidence for myocardial protection of cardioplegia in pediatric CPB.

Biomarkers in newborns with hypoxic-ischemic encephalopathy treated with therapeutic hypothermia

PURPOSE

The aim of the presented study was to evaluate the differences between selected biochemical markers in infants with moderate or severe hypoxic-ischemic encephalopathy (HIE) and their impact on patient prognosis.

METHODS

A total of 57 cooled newborns were divided into groups according to Sarnat staging of HIE (A, moderate vs. B, severe). The differences between groups were evaluated depending on the mode of delivery, pregnancy and labor complications, gestational age at birth, birth weight, and Apgar score at 1.3 and 5 min. The differences in biochemical biomarkers of HIE (pH, base excess, serum lactate) as well as biomarkers of hepatic injury (aspartate transaminase, (AST), alanine transaminase (ALT), prothrombin time (PT), and activated partial thromboplastin time (APTT)), kidney failure (creatinine, urea), myocardial injury (troponin T (TnT)), levels of fibrinogen, and platelet counts were also examined. Univariate Kaplan-Meier method was used for survival analyses.

RESULTS

The biomarker levels in severe HIE newborns compared with moderate were as follows: pH (7.10 vs. 6.99), serum lactate (22.50 vs. 17.00 mg/dL), AST (109.50 vs. 270.55 IU/L), ALT (27.30 vs. 108.05 IU/L), PT (17.00 vs. 44.20 s), APTT (47.75 vs. 47.90 s), TnT (0.22 vs. 0.85 ng/mL), creatinine (0.68 vs. 1.15 mg/dL), urea (44.55 vs. 73.30 mg/dL), and fibrinogen (1.65 vs. 1.90 mg/dL). Survival analyses showed significantly reduced survival for severe HIE infants (75%) vs. moderate HIE (100%).

CONCLUSION

In conclusion, the severity of HIE can be evaluated based on selected markers; however, their levels do not correspond with future prognosis of newborns.

Histological demonstration of BSEP/ABCB11 inhibition in transient neonatal cholestasis: a case report

BACKGROUND

Idiopathic or transient neonatal cholestasis (TNC) represents a group of cholestatic disorders with unidentified origin and remains a diagnosis of exclusion. Dysfunction of hepatobiliary transporters mediating excretion of biliary constituents from hepatocytes may play a central role in the pathogenesis of cholestasis. Despite variants of bile salt (BS) export pump (BSEP/ABCB11) have already been described in TNC, the pathogenic role of BSEP dysfunction in TNC remained so far elusive.

CASE PRESENTATION

We report on a newly-identified heterozygous ABCB11 missense variant (c.1345G > A, p.Glu449Lys) which was associated with prolonged cholestasis in a term infant after a complicated neonatal period. Moreover, we show for the first time almost completely abolished BSEP expression on the hepatocellular membrane in TNC.

CONCLUSION

This report demonstrates for the first time a close association between the prolonged cholestasis in infancy and impaired BSEP expression on the hepatocyte canalicular membrane in a heterozygous carrier of newly-identified ABCB11 variant.

System Specific Effects of Therapeutic Hypothermia with Neonatal Encephalopathy: Pearls for Clinicians

Neonatal encephalopathy (NE) is defined as a condition of impaired neurological function often caused by a peripartum event that impairs gas exchange resulting in hypoxia, hypercapnia, cerebral ischemia, and metabolic acidosis. NE is a significant cause of neonatal morbidity and mortality. Therapeutic hypothermia (TH) is the standard of care for the treatment of moderate and severe NE and has significantly improved long-term outcomes for affected infants. There are extensive systemic physiologic effects associated with TH that clinicians need to be aware of to optimize care for these infants. There is a paucity of literature that comprehensively identifies causal relationships between the physiologic and biochemical effects of TH. This can leave neonatal clinicians devoid of a comprehensive understanding of the medical management of NE. Therefore, this article seeks to help fill this gap, improve clinician knowledge base, and ultimately improve the care of infants undergoing TH.

Prediction of Drug Exposure in Critically Ill Encephalopathic Neonates Treated With Therapeutic Hypothermia Based on a Pooled Population Pharmacokinetic Analysis of Seven Drugs and Five Metabolites

Drug dosing in encephalopathic neonates treated with therapeutic hypothermia is challenging; exposure is dependent on body size and maturation but can also be influenced by factors related to disease and treatment. A better understanding of underlying pharmacokinetic principles is essential to guide drug dosing in this population. The prospective multicenter cohort study PharmaCool was designed to investigate the pharmacokinetics of commonly used drugs in neonatal encephalopathy. In the present study, all data obtained in the PharmaCool study were combined to study the structural system specific effects of body size, maturation, recovery of organ function, and temperature on drug clearance using nonlinear mixed effects modeling. Data collected during the first 5 days of life from 192 neonates treated with therapeutic hypothermia were included. An integrated population pharmacokinetic model of seven drugs (morphine, midazolam, lidocaine, phenobarbital, amoxicillin, gentamicin, and benzylpenicillin) and five metabolites (morphine-3-glucuronide, morphine-6-glucuronide, 1-hydroxymidazolam, hydroxymidazolam glucuronide, and monoethylglycylxylidide) was successfully developed based on previously developed models for the individual drugs. For all compounds, body size was related to clearance using allometric relationships and maturation was described with gestational age in a fixed sigmoidal Hill equation. Organ recovery after birth was incorporated using postnatal age. Clearance increased by 1.23%/hours of life (95% confidence interval (CI) 1.03-1.43) and by 0.54%/hours of life (95% CI 0.371-0.750) for high and intermediate clearance compounds, respectively. Therapeutic hypothermia reduced clearance of intermediate clearance compounds only, by 6.83%/°C (95% CI 5.16%/°C-8.34%/°C). This integrated model can be used to facilitate drug dosing and future pharmacokinetic studies in this population.

Management of Multi Organ Dysfunction in Neonatal Encephalopathy

Neonatal Encephalopathy (NE) describes neonates with disturbed neurological function in the first post-natal days of life. NE is an overall term that does not specify the etiology of the encephalopathy although it often involves hypoxia-ischaemia. In NE, although neurological dysfunction is part of the injury and is most predictive of long-term outcome, these infants may also have multiorgan injury and compromise, which further contribute to neurological impairment and long-term morbidities. Therapeutic hypothermia (TH) is the standard of care for moderate to severe NE. Infants with NE may have co-existing immune, respiratory, endocrine, renal, hepatic, and cardiac dysfunction that require individualized management and can be impacted by TH. Non-neurological organ dysfunction not only has a negative effect on long term outcome but may also influence the efficacy of treatments in the acute phase. Post resuscitative care involves stabilization and decisions regarding TH and management of multi-organ dysfunction. This management includes detailed neurological assessment, cardio-respiratory stabilization, glycaemic and fluid control, sepsis evaluation and antibiotics, seizure identification, and monitoring and responding to biochemical and coagulation derangements. The emergence of new biomarkers of specific organ injury may have predictive value and improve the definition of organ injury and prognosis. Further evidence-based research is needed to optimize management of NE, prevent further organ dysfunction and reduce neurodevelopmental impairment.

A Physiology-Based Pharmacokinetic Framework to Support Drug Development and Dose Precision During Therapeutic Hypothermia in Neonates

Therapeutic hypothermia (TH) is standard treatment for neonates (≥36 weeks) with perinatal asphyxia (PA) and hypoxic-ischemic encephalopathy. TH reduces mortality and neurodevelopmental disability due to reduced metabolic rate and decreased neuronal apoptosis. Since both hypothermia and PA influence physiology, they are expected to alter pharmacokinetics (PK). Tools for personalized dosing in this setting are lacking. A neonatal hypothermia physiology-based PK (PBPK) framework would enable precision dosing in the clinic. In this literature review, the stepwise approach, benefits and challenges to develop such a PBPK framework are covered. It hereby contributes to explore the impact of non-maturational PK covariates. First, the current evidence as well as knowledge gaps on the impact of PA and TH on drug absorption, distribution, metabolism and excretion in neonates is summarized. While reduced renal drug elimination is well-documented in neonates with PA undergoing hypothermia, knowledge of the impact on drug metabolism is limited. Second, a multidisciplinary approach to develop a neonatal hypothermia PBPK framework is presented. Insights on the effect of hypothermia on hepatic drug elimination can partly be generated from in vitro (human/animal) profiling of hepatic drug metabolizing enzymes and transporters. Also, endogenous biomarkers may be evaluated as surrogate for metabolic activity. To distinguish the impact of PA versus hypothermia on drug metabolism, in vivo neonatal animal data are needed. The conventional pig is a well-established model for PA and the neonatal Göttingen minipig should be further explored for PA under hypothermia conditions, as it is the most commonly used pig strain in nonclinical drug development. Finally, a strategy is proposed for establishing and fine-tuning compound-specific PBPK models for this application. Besides improvement of clinical exposure predictions of drugs used during hypothermia, the developed PBPK models can be applied in drug development. Add-on pharmacotherapies to further improve outcome in neonates undergoing hypothermia are under investigation, all in need for dosing guidance. Furthermore, the hypothermia PBPK framework can be used to develop temperature-driven PBPK models for other populations or indications. The applicability of the proposed workflow and the challenges in the development of the PBPK framework are illustrated for midazolam as model drug.

Clinical Characteristics of Hospitalized Neonates With Hypofibrinogenemia: A Retrospective Cohort Study

Background: Neonatal hypofibrinogenemia is often asymptomatic but can manifest as hemorrhage. Objective: This study was conducted to characterize clinical characteristics of neonates with hypofibrinogenemia and identify factors associated with hemorrhage. Methods: This was a retrospective study of neonates with plasma fibrinogen level (FIB) ≤1.0 g/L who were hospitalized at the Neonatology Department, People's Hospital, Chongqing, China, from January 2012 to December 2017. Based on severity, patients were grouped into severe, moderate, and mild hypofibrinogenemia (FIB < 0.5 g/L, 0.5 g/L ≤ FIB < 0.7 g/L, and 0.7 g/L ≤ FIB ≤ 1.0 g/L, respectively). Clinical characteristics associated with hemorrhage were analyzed. Results: Among 330 neonates, 52.7% showed mild hypofibrinogenemia, 25.5% had moderate hypofibrinogenemia, and 21.8% had severe hypofibrinogenemia. Severe hypofibrinogenemia was not associated with gestational age, but the mild form was frequent in neonates with low/normal birthweight (P = 0.018). Approximately 80.6% of neonates presented hypofibrinogenemia as variable combinations of thrombocytopenia or coagulopathies. Hemorrhage occurred in 38.8% of the cases, 60.9% of which were mild. Hemorrhage manifested as puncture site bleeding (47.7%) or spontaneous skin/mucous membrane bleeding (34.2%). The degree of hypofibrinogenemia was not associated with the severity or occurrence of hemorrhage. Among patients with hypofibrinogenemia and bleeding, 53.4% of the cases with coagulopathies showed mild hemorrhage, 85.7% of the cases with thrombocytopenia had moderate bleeding, while 53.8% of the cases with coagulopathy and thrombocytopenia showed severe hemorrhage. Conclusion: Neonatal hypofibrinogenemia is often comorbid and occurs with thrombocytopenia and/or coagulopathies. Although hemorrhage is not associated with the degree of hypofibrinogenemia, it may be severe when hypofibrinogenemia co-occurs with coagulopathies and/or thrombocytopenia.

Potential protective effects of bilirubin following the treatment of neonatal hypoxic-ischemic encephalopathy with hypothermia therapy

Background: Therapeutic hypothermia (TH) is the standard therapy for hypoxic-ischemic encephalopathy (HIE) and is associated with a wide range of physiological changes. Objective: We re-evaluated the effects of HIE and TH on bilirubin measurements following HIE in a center involved in the China cooling randomized controlled trial (RCT). Methods: Serial serum bilirubin concentrations measured during the first week of life were compared among the HIE + NT (normothermia) group, HIE + TH treatment group and control group (without HIE). Survivors of HIE were followed and assessed at approximately 2 years of age, and the results were correlated with peak bilirubin levels during the first week of life. Results: One hundred and thirty-eight infants were available for analysis. Significantly lower bilirubin levels were recorded in the HIE + NT group than in the controls (P<0.05). Significant differences were not observed among the patients in the HIE + NT group (mild to severe) or between the HIE + TH group and the HIE + NT group at any time point (P>0.05). The peak serum bilirubin concentrations recorded at 96 h of age showed a good correlation with the results of the Bayley Scales of Infant and Toddler Development, third edition (BSID-III) (P=0.02). Conclusion: Bilirubin potentially exerts a neuroprotective effect during the first week of life, and low temperature does not affect the possible antioxidant function of bilirubin during TH following HIE.

Pharmacokinetics of morphine in encephalopathic neonates treated with therapeutic hypothermia

OBJECTIVE

Morphine is a commonly used drug in encephalopathic neonates treated with therapeutic hypothermia after perinatal asphyxia. Pharmacokinetics and optimal dosing of morphine in this population are largely unknown. The objective of this study was to describe pharmacokinetics of morphine and its metabolites morphine-3-glucuronide and morphine-6-glucuronide in encephalopathic neonates treated with therapeutic hypothermia and to develop pharmacokinetics based dosing guidelines for this population.

STUDY DESIGN

Term and near-term encephalopathic neonates treated with therapeutic hypothermia and receiving morphine were included in two multicenter cohort studies between 2008-2010 (SHIVER) and 2010-2014 (PharmaCool). Data were collected during hypothermia and rewarming, including blood samples for quantification of morphine and its metabolites. Parental informed consent was obtained for all participants.

RESULTS

244 patients (GA mean (sd) 39.8 (1.6) weeks, BW mean (sd) 3,428 (613) g, male 61.5%) were included. Morphine clearance was reduced under hypothermia (33.5°C) by 6.89%/°C (95% CI 5.37%/°C- 8.41%/°C, p<0.001) and metabolite clearance by 4.91%/°C (95% CI 3.53%/°C- 6.22%/°C, p<0.001) compared to normothermia (36.5°C). Simulations showed that a loading dose of 50 μg/kg followed by continuous infusion of 5 μg/kg/h resulted in morphine plasma concentrations in the desired range (between 10 and 40 μg/L) during hypothermia.

CONCLUSIONS

Clearance of morphine and its metabolites in neonates is affected by therapeutic hypothermia. The regimen suggested by the simulations will be sufficient in the majority of patients. However, due to the large interpatient variability a higher dose might be necessary in individual patients to achieve the desired effect.

TRIAL REGISTRATION

www.trialregister.nl NTR2529.

Changes in bilirubin in infants with hypoxic-ischemic encephalopathy

Antioxidant properties of bilirubin have been reported in many studies. We hypothesized that bilirubin might be involved in neuroprotection mechanisms against oxidative stress in infants with hypoxic-ischemic encephalopathy (HIE) and that total serum bilirubin (TSB) might increase in these patients. We retrospectively studied infants with gestational age ≥ 35 weeks and birth weight ≥ 1800 g who were admitted to the neonatal intensive care unit (NICU) with a diagnosis of moderate-to-severe HIE and received or did not receive therapeutic hypothermia. We evaluated peak TSB and changes of mean TSB in these patients in comparison with a control group of infants admitted to the NICU with diagnoses other than HIE. Peak and mean TSB values were lower in the no hypothermia and hypothermia groups in comparison with the control group, while differences were not noted between infants who received hypothermia or did not. Regression analysis showed that HIE and hypothermia significantly reduced the risk of developing TSB values higher than median value (> 8.4 mg/dL) in our population.Conclusion: Peak and mean TSB values were lower in infants with moderate-to-severe HIE than in control infants. HIE and hypothermia independently decreased TSB. These results exclude a TSB increase as a neuroprotective mechanism in infants with HIE. We speculated that low TSB values in infants with HIE could be due to hypoxic repression of HO expression and represent a defensive strategy for limiting brain injuries in these patients. What is Known: • The role of oxidative stress in the pathophysiology of hypoxic-ischemic encephalopathy (HIE) has been elucidated in many studies, and other studies have demonstrated the antioxidant properties of bilirubin. • The potential neuroprotective role of bilirubin as antioxidant agent has never been evaluated in infants with HIE. What is New: • Mean total serum bilirubin (TSB) values are lower in infants with moderate-to-severe HIE than in control infants, since HIE and hypothermia independently decreased TSB. • An increase in bilirubin was not a neuroprotective mechanism in infants with HIE possibly because of hypoxic repression of HO expression as defensive strategy for limiting brain injuries.