Whole-body hypothermia for neonates with hypoxic-ischemic encephalopathy

Individualized Neuroprognostication in Neonates With Hypoxic-Ischemic Encephalopathy Treated With Hypothermia

Background and Objectives

To determine whether post-rewarming brain MRI enables individualized domain-specific prediction of neurodevelopmental outcomes at 2 years of age in infants treated with hypothermia for hypoxic-ischemic brain injury.

Methods

We conducted a retrospective multicenter study of infants with moderate-to-severe hypoxic-ischemic encephalopathy (HIE) treated with hypothermia. Brain MRI abnormalities and the prediction of domain-specific 2-year neurodevelopmental outcomes were scored independently by 2 investigators after which consensus was reached for both imaging findings and outcome prediction. Neuroimaging patterns were categorized as normal, white matter (WM)/watershed-predominant, deep gray matter (DGM)-predominant, and near-total injury. Outcomes were predicted separately for mortality, cerebral palsy (CP) type and severity, cognitive delay, epilepsy, cerebral visual impairment (CVI), and feeding difficulties; these outcomes were predicted as highly unlikely, possible, probable, or highly likely.

Results

Of the 152 study infants, 27 (18%) died. The neurodevelopmental outcome at 2 years was available in all 125 survivors. CP was seen in 21 of 125 surviving infants (17%). No infants in the highly unlikely category developed CP while 90% in the highly likely category did. When CP was predicted as possible, 40% developed CP; all were mild and ambulatory. When CP was predicted as probable, 67% developed CP of whom 40% were severe and nonambulatory. Cognitive scores were available in 104 of 125 infants (83%). Cognitive delay was seen in 23 of 104 infants (22%) (15% mild and 7% severe). When cognitive delay was predicted as highly unlikely, 92% did not develop cognitive delay and the delay was mild in those who did. When cognitive delay was considered highly likely, this developed in 100%. When epilepsy, CVI, and feeding problems were predicted as highly unlikely, 98% did not develop epilepsy; for CVI and feeding problems, this was 100% and 97%, respectively. In 27 of 152 infants (18%), the investigators reached consensus that the overall injury was severe enough to consider redirection of care; 21 of 27 infants (78%) died. Of the survivors, 5 infants developed severe CP and 1 had a mild dyskinetic CP with swallowing problems and CVI.

Discussion

Individualized domain-specific categorical neuroprognostication mainly based on brain MRI is feasible, reliable, and highly accurate in infants with HIE.

Analysis of CTG patterns in cases with metabolic acidosis at birth with and without neonatal neurological alterations

OBJECTIVE

To determine cardiotocographic patterns in newborns with metabolic acidosis, based on clinical signs of neurological alteration (NA) and the need for hypothermic treatment.

METHODS

All term newborns with metabolic acidosis in a single center from 2016 to 2020 were included in the study. Three segments of intrapartum CTG (cardiotocography) were considered (first 30 min of active labor, 90 to 30 min before birth, and last 30 min before delivery) and a longitudinal analysis of CTG pattern was performed according to the 2015 FIGO classification.

RESULTS

Three hundred and twenty-four neonates with metabolic acidosis diagnosed at birth were divided into three groups: the first group included all neonates with any clinical sign of neurological alteration, requiring hypothermia according to the recommendation of the Italian Society of Neonatology (group TNA-Treated neurological Alteration, n = 17), the second encompassed neonates with any clinical sign of neurological alteration not requiring hypothermia (group NTNA-Not Treated neurological Alteration, n = 83), and the third enclosed all neonates without any sign of clinical neurological involvement (group NoNA-No neurological Alteration, n = 224). The most frequent alterations of CTG in TNA group were late decelerations, reduced variability, bradycardia, and tachysystole. Unexpectedly, from the longitudinal analysis of the CTG, 49% of all cases with metabolic acidosis never showed a pathological CTG with normal trace at the beginning of labor followed by normal or suspicious trace in the final part of labor, the same as in TNA and NTNA groups (10 and 39%, respectively).

CONCLUSIONS

CTG has limited specificity in identifying cases of acidosis at birth, even in babies who will develop NA.

Cardiac function at follow-up in infants treated with therapeutic hypothermia for neonatal hypoxic-ischemic encephalopathy

BACKGROUND

Compromised myocardial function and persistent elevated pulmonary vascular resistance are common among neonates treated with therapeutic hypothermia (TH) for hypoxic-ischemic encephalopathy (HIE). There is a lack of data regarding persistence of cardiac alterations after discharge from the neonatal intensive care unit (NICU).

METHODS

We assessed cardiovascular profiles after NICU discharge. Echocardiogram data, including speckle-tracking echocardiography (STE), were extracted from the latest outpatient scan. Data were compared by initial amplitude-integrated encephalography (aEEG) profiles on admission [normal vs. abnormal].

RESULTS

In total, 70 (19%) neonates had a follow-up echocardiogram (22 with initial normal aEEG, 48 with abnormal aEEG). Age at follow-up was similar between the two groups (6.2 vs. 7.7 months, [p = 0.08]). Neonates with an initially abnormal aEEG showed more negative Right Ventricle (RV)-peak global longitudinal strain (-28.2 vs. -26.0%, [p = 0.02]), RV-peak free wall longitudinal strain rate (-1.24 vs. -1.10 [1/second], [p = 0.01]), and RV-peak free wall longitudinal strain rate (-1.50 vs. -1.27 [1/second], [p = 0.001]). These associations remained after multilinear regression analysis, indicating persistent enhanced RV contraction in the abnormal aEEG group.

CONCLUSION

Neonates with initial abnormal aEEG profiles exhibited increased RV contraction after NICU discharge. Future studies should explore long-term cardiovascular follow-up of neonates with HIE, beyond the perinatal period.

IMPACT

What is the key message of your article? Cardiac performance in hypoxic ischemic encephalopathy is linked to adverse outcomes. Survivors with an abnormal aEEG at admission showed increased right ventricular contractility at follow-up, possibly related to an adverse adaptation to the initial insult. What does it add to the existing literature? This study offers insights into long-term cardiovascular outcomes in neonates with HIE, focusing on the link between initial aEEG abnormalities and later RV function. What is the impact? The findings underscore the importance of early cardiovascular assessments and monitoring in neonates undergoing TH for HIE, potentially guiding future follow-up protocols.

Neonatal hypoxia-ischemia alters the events governing the hippocampal critical period of postnatal synaptic plasticity leading to deficits in working memory in mice

The postnatal critical period of synaptic plasticity (CPsp) is characterized by profound neural network refinement, which is shaped by synaptic activity and sculpted by maturation of the GABAergic network. Even after therapeutic hypothermia (TH), neonatal hypoxia-ischemia (HI) impairs two triggers for the initiation of the CPsp in the hippocampus: i) PSA-NCAM developmental decline and ii) parvalbumin (PV) + interneuron (IN) maturation. Thus, we investigated whether neonatal HI despite TH disturbs other events governing the onset, consolidation and closure of the postnatal CPsp in the hippocampus. We induced cerebral HI in P10 C57BL6 mice with right carotid ligation and 45 m of hypoxia (FiO2 = 0.08), followed by normothermia (36 °C, NT) or TH (31 °C) for 4 h with anesthesia-exposed shams as controls. ELISA, immunoblotting and immunohistochemistry were performed at 24 h (P11), 5 days (P15), 8 days (P18) and 30 days (P40) after HI injury. We specifically assessed: i) BDNF levels and TrkB activation, controlling the CPsp, ii) Otx2 and NPTX2 immunoreactivity (IR), engaging CPsp onset and iii) NogoR1, Lynx1 IR, PNN formation and myelination (MBP) mediating CPsp closure. Pups aged to P40 also received a battery of tests assessing working memory. Here, we documented deficits in hippocampal BDNF levels and TrkB activation at P18 in response to neonatal HI even with TH. Neonatal HI impaired in the CA1 the developmental increase in PV, Otx2, and NPTX2 between P11 and P18, the colocalization of Otx2 and PV at P18 and P40, the accumulation of NPTX2 in PV+ dendrites at P18 and P40, and the expression of NogoR and Lynx1 at P40. Furthermore, neonatal HI decreased BDNF and impaired PNN development and myelination (MBP) at P40. Most of these abnormalities were insensitive to TH and correlated with memory deficits. Neonatal HI appears to disrupt many of the molecular and structural events initiating and consolidating the postnatal hippocampal CPsp, perhaps due to the early and delayed deficits in TrkB activation leading to memory deficits.

The effects of nutrition on mesenteric oxygenation among neonates with neonatal encephalopathy: a randomized clinical trial

BACKGROUND

We aimed to evaluate the effects of minimal enteral nutrition (MEN) on mesenteric blood flow and oxygenation with Doppler USG and Near Infrared Spectroscopy (NIRS) during therapeutic hypothermia (TH) in babies with HIE.

METHODS

This prospective, randomized-controlled study was composed of infants receiving MEN (study group, n = 30) and infants who were not fed (control group, n = 30) during hypothermia. Infants were monitored continuously with NIRS and mesenteric blood flow velocities were measured with Doppler USG before and after feeding.

RESULTS

The mean gestational age and birth weight for the study and control group were 38.73 ± 1.5-39.09 ± 1.02 weeks and 3076 ± 280.4-3295 ± 391 grams, respectively. Time to reach full enteral nutrition and hospital stay were significantly shorter in the study group (p = 0.049, p = 0.016). Infants in the study group experienced less feeding intolerance (p = 0.006). No infant developed necrotizing enterocolitis (NEC) in both groups. No difference was determined in pre- and post-feeding cerebral rSO2 measurements during TH and normothermia. Mesenteric rSO2, CSOR, and mesenteric blood flow measurements in the study group during normothermia were significantly increased, respectively (p = 0.03, p < 0.01, p < 0.01).

CONCLUSION

In our study, we observed that MEN during TH does not lead to a significant change in cerebral and mesenteric oxygenation. Although we did not observe an increase in blood flow and oxygenation, the absence of NEC and a lower incidence of feeding intolerance in the study group may suggest that feeding during TH is safe and feasible.

IMPACT

MEN during TH treatment does not lead to a significant change in cerebral and mesenteric oxygenation. This is the first study evaluating the effects of MEN on mesenteric oxygenation and blood flow velocities in infants with hypoxic-ischemic encephalopathy during TH with Doppler USG and NIRS, concomitantly. MEN during TH may be safe and feasible.

Machine learning models of cerebral oxygenation (rcSO2) for brain injury detection in neonates with hypoxic-ischaemic encephalopathy

The present study was designed to test the potential utility of regional cerebral oxygen saturation (rcSO2) in detecting term infants with brain injury. The study also examined whether quantitative rcSO2 features are associated with grade of hypoxic ischaemic encephalopathy (HIE). We analysed 58 term infants with HIE (>36 weeks of gestational age) enrolled in a prospective observational study. All newborn infants had a period of continuous rcSO2 monitoring and magnetic resonance imaging (MRI) assessment during the first week of life. rcSO2 Signals were pre-processed and quantitative features were extracted. Machine-learning and deep-learning models were developed to detect adverse outcome (brain injury on MRI or death in the first week) using the leave-one-out cross-validation approach and to assess the association between rcSO2 and HIE grade (modified Sarnat - at 1 h). The machine-learning model (rcSO2 excluding prolonged relative desaturations) significantly detected infant MRI outcome or death in the first week of life [area under the curve (AUC) = 0.73, confidence interval (CI) = 0.59-0.86, Matthew's correlation coefficient = 0.35]. In agreement, deep learning models detected adverse outcome with an AUC = 0.64, CI = 0.50-0.79. We also report a significant association between rcSO2 features and HIE grade using a machine learning approach (AUC = 0.81, CI = 0.73-0.90). We conclude that automated analysis of rcSO2 using machine learning methods in term infants with HIE was able to determine, with modest accuracy, infants with adverse outcome. De novo approaches to signal analysis of NIRS holds promise to aid clinical decision making in the future. KEY POINTS: Hypoxic-induced neonatal brain injury contributes to both short- and long-term functional deficits. Non-invasive continuous monitoring of brain oxygenation using near-infrared- spectroscopy offers a potential new insight to the development of serious injury. In this study, characteristics of the NIRS signal were summarised using either predefined features or data-driven feature extraction, both were combined with a machine learning approach to predict short-term brain injury. Using data from a cohort of term infants with hypoxic ischaemic encephalopathy, the present study illustrates that automated analysis of regional cerebral oxygen saturation rcSO2, using either machine learning or deep learning methods, was able to determine infants with adverse outcome.

Safety and tolerability of a Muse cell-based product in neonatal hypoxic-ischemic encephalopathy with therapeutic hypothermia (SHIELD trial)

Hypoxic-ischemic encephalopathy (HIE), associated with high mortality and neurological sequelae, lacks established treatment except therapeutic hypothermia. Clinical-grade multilineage-differentiating stress-enduring (Muse) cells (CL2020) demonstrated safety and efficacy in nonclinical HIE rat models, thereby leading to an investigator-initiated clinical trial to evaluate CL2020 safety and tolerability in neonatal HIE as a single-center open-label dose-escalation study with 9 neonates with moderate-to-severe HIE who received therapeutic hypothermia. Each patient received a single intravenous injection of CL2020 cells between 5 and 14 days of age. The low-dose (3 patients) and high-dose (6 patients) groups received 1.5 × 106 and 1.5 × 107 cells/dose, respectively. The occurrence of any adverse event within 12 weeks following CL2020 administration was the primary endpoint of this trial. No significant changes in physiological signs including heart rate, blood pressure, and oxygen saturation were observed during or after administration. The only adverse event that may be related to cell administration was a mild γ-glutamyltransferase level elevation in one neonate, which spontaneously resolved without any treatment. All patients enrolled in the trial survived, and normal developmental quotients (≥ 85) in all 3 domains of the Kyoto Scale of Psychological Development 2001 were observed in 67% of the patients in this trial. CL2020 administration was demonstrated to be safe and tolerable for neonates with HIE. Considering the small number of patients, a randomized controlled confirmatory study is warranted to verify these preliminary findings and evaluate the efficacy of this therapy.

Improving the future of clinical trials and translation of mesenchymal stromal cell therapies for neonatal disorders

Despite recent advances in neonatal intensive care medicine, neonatal disorders such as (bronchopulmonary dysplasia [BPD], intraventricular hemorrhage [IVH], and hypoxic ischemic encephalopathy [HIE]) remain major causes of death and morbidity in survivors, with few effective treatments being available. Recent preclinical studies have demonstrated the pleiotropic host injury-responsive paracrine protective effects of cell therapy especially with mesenchymal stromal cells (MSCs) against BPD, IVH, and HIE. These findings suggest that MSCs therapy might emerge as a novel therapeutic modality for these currently devastating neonatal disorders with complex multifactorial etiologies. Although early-phase clinical trials suggest their safety and feasibility, their clinical therapeutic benefits have not yet been proven. Therefore, based on currently available preclinical research and clinical trial data, we focus on critical issues that need to be addressed for future successful clinical trials and eventual clinical translation such as selecting the right patient and optimal cell type, route, dose, and timing of MSCs therapy for neonatal disorders such as BPD, HIE, and IVH.

Adjuvant High-Dose Erythropoietin With Delayed Therapeutic Hypothermia in Neonatal Hypoxic-Ischemic Encephalopathy

BACKGROUND

To evaluate the benefits of high-dose erythropoietin (EPO) combined with therapeutic hypothermia (TH) on brain magnetic resonance imaging (MRI) scores and neurodevelopmental outcomes in neonates with moderate to severe hypoxic-ischemic-ecephalopathy (HIE), especially in neonates who received TH between six to 12 hours of birth.

METHODS

This prospective, single-blind, randomized, placebo-controlled trial enrolled term newborns with moderate to severe HIE admitted to neonatal intensive care unit between April 2018 and April 2022. Hypothermia was started within 12 hours of birth. Infants were randomized to receive EPO 1000 U/kg or an equal volume of normal saline (placebo) on days 1, 2, 3, 5, and 7 of age in combination with hypothermia.

RESULTS

Fifty-seven neonates with moderate to severe HIE were recruited; 10 were excluded. Forty-seven patients were included: 32 received TH within six hours (group I) and in 15 TH was started within six to 12 hours of birth (group II). The clinical characteristics of mothers and infants, maternal complications, and resuscitations performed during the perinatal period showed no statistical differences between EPO group and placebo groups I and II. The MRI scores and brain injury patterns did not differ between the EPO and placebo groups. There is no statistical significance in either group's seizure and severe electroencephalography background (initial and after rewarming) between EPO and placebo in each group. There were no differences in developmental outcomes (abnormal Denver II > 2 area, Gross Motor Function Classification Score >1); Bayley Scales of Infant and Toddler Development, third edition (BSID-III) score (cognitive, language, and motor); or disability (hearing impairment and impaired vision) between the EPO and placebo groups I and II at 12 and 18 months.

CONCLUSIONS

Among term infants with moderate to severe HIE, TH with EPO administration, compared with TH alone, did not reduce brain injury on MRI or the risk of neurological sequelae both in patients who received TH within six hours and in those who received TH later (six to 12 hours). Further studies on the benefit of EPO injection alone or before TH in situations where TH cannot be performed are required.

Risk factors, incidence, and outcomes of neonatal respiratory extracorporeal membrane oxygenation including association with therapeutic hypothermia in California during 2013-2020

OBJECTIVE

To evaluate the incidence, indications and outcomes with neonatal extracorporeal membrane oxygenation (ECMO) and its association with therapeutic hypothermia (TH) among infants undergoing invasive mechanical ventilation (IMV) in California during 2013-2020.

STUDY DESIGN

We analyzed data on neonates ≥34 weeks gestation with ≥4 h of IMV over an 8-year period (2013-2020) from the California Perinatal Quality Care Collaborative (CPQCC) database.

RESULTS

Between 2013 and 2020, the ranges for utilization of iNO (13.9 to 17.2%), ECMO (2.1 to 2.5%), TH (10.2 to 15.7%) and TH + ECMO (0.4 to 0.8%) were observed. The most common association with neonatal ECMO was TH (148 cases, OR 3.2, 95% CI 2.6-4.3, p < 0.01). The combination of meconium aspiration syndrome (MAS) and hypoxic ischemic encephalopathy (HIE) increased risk of iNO and ECMO use (OR 11.3, 1.5-86.9), p = 0.02).

CONCLUSION

Ventilated infants ≥34 weeks gestational age undergoing TH are at risk for iNO/ECMO use and need close monitoring.

Neocortical cholinergic pathology after neonatal brain injury is increased by Alzheimer's disease-related genes in mice

Hypoxic-ischemic encephalopathy (HIE) in neonates causes mortality and neurologic morbidity, including poor cognition with a complex neuropathology. Injury to the cholinergic basal forebrain and its rich innervation of cerebral cortex may also drive cognitive pathology. It is uncertain whether genes associated with adult cognition-related neurodegeneration worsen outcomes after neonatal HIE. We hypothesized that neocortical damage caused by neonatal HI in mice is ushered by persistent cholinergic innervation and interneuron (IN) pathology that correlates with cognitive outcome and is exacerbated by genes linked to Alzheimer's disease. We subjected non-transgenic (nTg) C57Bl6 mice and mice transgenically (Tg) expressing human mutant amyloid precursor protein (APP-Swedish variant) and mutant presenilin (PS1-ΔE9) to the Rice-Vannucci HI model on postnatal day 10 (P10). nTg and Tg mice with sham procedure were controls. Visual discrimination (VD) was tested for cognition. Cortical and hippocampal cholinergic axonal and IN pathology and Aβ plaques, identified by immunohistochemistry for choline acetyltransferase (ChAT) and 6E10 antibody respectively, were counted at P210. Simple ChAT+ axonal swellings were present in all sham and HI groups; Tg mice had more than their nTg counterparts, but HI did not affect the number of axonal swellings in APP/PS1 Tg mice. In contrast, complex ChAT+ neuritic clusters (NC) occurred only in Tg mice; HI increased that burden. The abundance of ChAT+ clusters in specific regions correlated with decreased VD. The frequency of attritional ChAT+ INs in the entorhinal cortex (EC) was increased in Tg shams relative to their nTg counterparts, but HI obviated this difference. Cholinergic IN pathology in EC correlated with NC number. The Aβ deposition in APP/PS1 Tg mice was not exacerbated by HI, nor did it correlate with other metrics. Adult APP/PS1 Tg mice have significant cortical cholinergic axon and EC ChAT+ IN pathologies; some pathology was exacerbated by neonatal HI and correlated with VD. Mechanisms of neonatal HI induced cognitive deficits and cortical neuropathology may be modulated by genetic risk, perhaps accounting for some of the variability in outcomes.

Coagulation profiles and percentiles in neonates with hypoxic-ischemic encephalopathy undergoing therapeutic hypothermia: A step toward more accurate transfusion thresholds

BACKGROUND

In the literature, there are no studies about the transfusion threshold for neonates with hypoxic-ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH). In order to facilitate accurate interpretation of coagulation results in these neonates, we aimed to generate specific reference intervals in this specific population.

METHODS

This retrospective study included all HIE neonates admitted from 2014 to 2022 to undergo TH. All infants during TH underwent blood exams, including the coagulation profile. Our primary outcome was to assess the estimates of the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles for each parameter on admission (before transfusion). By the receiver operating characteristic (ROC) analysis, the area under the ROC curve (AUC) and the best cut-off point were used to evaluate the ability of the prothrombin time expressed as international normalized ratio (PT-INR) to predict the risk of any bleeding.

RESULTS

A total of 143 infants were included in this study. On admission, the median fibrinogen value was 205 mg/dL, prothrombin time 18.6 seconds, PT-INR 1.50, activated partial thromboplastin time 38.3 seconds, thrombin time 18.6 seconds, antithrombin 57.0%. The optimal cut-off of PT-INR in predicting the risk of any bleeding was greater than 1.84 (AUC .623, p = .024).

CONCLUSION

For the first time, we proposed the percentiles of coagulation parameters in our cohort of neonates with HIE. Furthermore, we found that a PT-INR greater than 1.84 can significantly predict the risk of any bleeding. Further studies are needed to determine if a restrictive versus a liberal transfusion approach can be equally safer for these high-risk infants.

Regional variability in therapeutic hypothermia eligibility criteria for neonatal hypoxic-ischemic encephalopathy

Early induced therapeutic hypothermia represents the cornerstone treatment in neonates with probable hypoxic-ischemic encephalopathy. The selection of patients for treatment usually involves meeting criteria indicating evidence of perinatal hypoxia-ischemia and the presence of moderate or severe encephalopathy. In this review, we highlight the variability that exists between some of the different regional and national eligibility guidelines. Determining the potential presence of perinatal hypoxia-ischemia may require either one, two or three signs amongst history of acute perinatal event, prolonged resuscitation at delivery, abnormal blood gases and low Apgar score, with a range of cutoff values. Clinical neurological exams often define the severity of encephalopathy differently, with varying number of domains required for determining eligibility and blurred interpretation of findings assigned to different severity grades in different systems. The role of early electrophysiological assessment is weighted differently. A clinical implication is that infants may receive different care depending on the location in which they are born. This could also impact epidemiological data, as inference of rates of moderate-severe encephalopathy based on therapeutic hypothermia rates are misleading and influenced by different eligibility methods used. We would advocate that a universally endorsed single severity staging of encephalopathy is vital for standardizing management and neonatal outcome. IMPACT: Variability exists between regional and national therapeutic hypothermia eligibility guidelines for neonates with probable hypoxic-ischemic encephalopathy. Differences are common in both criteria indicating perinatal hypoxia-ischemia and criteria defining moderate or severe encephalopathy. The role of early electrophysiological assessment is also weighted unequally. This reflects in different individual care and impacts research data. A universally endorsed single severity staging of encephalopathy would be crucial for standardizing management.

Neonatal encephalopathy multiorgan scoring systems: systematic review

Introduction

Neonatal encephalopathy (NE) is a condition with multifactorial etiology that causes multiorgan injury to neonates. The severity of multiorgan dysfunction (MOD) in NE varies, with therapeutic hypothermia (TH) as the standard of care. The aim is to identify current approaches used to assess and determine an optimum scoring system for MOD in NE.

Methods

The systematic review conformed to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search was conducted using PubMed, EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, Scopus, and CINAHL for studies of scoring systems for MOD in NE.

Results

The search yielded 628 articles of which 12 studies were included for data extraction and analysis. Five studies found a positive correlation between the severity of NE and MOD. There was significant heterogeneity across the scoring systems, including the eligibility criteria for participants, the methods assessing specific organ systems, the length of follow-up, and adverse outcomes. The neurological, hepatic, cardiovascular, respiratory, hematological, and renal systems were included in most studies while the gastrointestinal system was only in three studies. The definitions for hepatic, renal, and respiratory systems dysfunction were most consistent while the cardiovascular system varied the most.

Discussion

A NE multiorgan scoring system should ideally include the renal, hepatic, respiratory, neurological, hematological, and cardiovascular systems. Despite the heterogeneity between the studies, these provide potential candidates for the standardization of MOD scoring systems in NE. Validation is needed for the parameters with adequate length of follow-up beyond the neonatal period. Additionally, the evaluation of MOD may be affected by TH considering its multiorgan effects.

Oral Clonidine-Based Strategy to Reduce Opiate Use During Cooling for Neonatal Encephalopathy: An Observational Study

OBJECTIVE

To determine whether an enteral, clonidine-based sedation strategy (CLON) during therapeutic hypothermia (TH) for hypoxic-ischemic encephalopathy would decrease opiate use while maintaining similar short-term safety and efficacy profiles to a morphine-based strategy (MOR).

STUDY DESIGN

This was a single-center, observational study conducted at a level IV neonatal intensive care unit from January 1, 2017, to October 1, 2021. From April 13, 2020, to August 13, 2020, we transitioned from MOR to CLON. Thus, patients receiving TH for hypoxic-ischemic encephalopathy were grouped to MOR (before April 13, 2020) and CLON (after August 13, 2020). We calculated the total and rescue morphine milligram equivalent/kg (primary outcome) and frequency of hemodynamic changes (secondary outcome) for both groups.

RESULTS

The MOR and CLON groups (74 and 25 neonates, respectively) had similar baseline characteristics and need for rescue sedative intravenous infusion (21.6% MOR and 20% CLON). Both morphine milligram equivalent/kg and need for rescue opiates (combined bolus and infusions) were greater in MOR than CLON (P < .001). As days in TH advanced, a lower percentage of patients receiving CLON needed rescue opiates (92% on day 1 to 68% on day 3). Patients receiving MOR received a greater cumulative dose of dopamine and more frequently required a second inotrope and hydrocortisone for hypotension. MOR had a lower respiratory rate during TH (P = .01 vs CLON).

CONCLUSIONS

Our CLON protocol is noninferior to MOR, maintaining perceived effectiveness and hemodynamic safety, with an apparently reduced need for opiates and inotropes.

Blood product transfusion practices in neonates with hypoxic-ischemic encephalopathy

OBJECTIVE

Blood product transfusion is a common practice in infants with hypoxic-ischemic encephalopathy (HIE) undoing therapeutic hypothermia (TH). The advantages and disadvantages of conservative or liberal transfusion practices in this fragile population are unknown. Study aims to characterize the transfusion practices in infants with HIE and investigate the association with outcome.

STUDY DESIGN

We conducted a retrospective cohort study at a single level IV NICU, evaluating transfusion thresholds, as well as the association between hematological abnormalities or blood product transfusions and outcomes in infants admitted with HIE.

RESULT

By univariate analysis, FFP transfusion was associated with increased in-hospital death. However, multivariate analysis adjusting for HIE severity demonstrated no association between hematological abnormality or blood product transfusion and death, nor with neurodevelopmental impairment.

CONCLUSION

No association was found between hematological blood product transfusion and death or neurodevelopmental impairment in a retrospective single NICU study of infants with HIE.

RBM3 Promotes Anti-inflammatory Responses in Microglia and Serves as a Neuroprotective Target of Ischemic Stroke

Ischemic stroke is a major cause of death and disability in adults. Hypothermic treatment is successful in treating neonatal cerebral ischemia, but its application is restricted in adult patients due to complex management strategies and severe adverse effects. Two homologous RNA-binding proteins, RBM3 and CIRP, are the only known cold-inducible proteins in vertebrates, and their expression levels are robustly elevated by mild to moderate hypothermia. In previous studies, we and others have demonstrated that both RBM3 and CIRP mediate the neuroprotective and neurogenic effects of hypothermia in cell and animal models. However, CIRP can also be detrimental to neurons by triggering neuroinflammatory responses, complicating its post-stroke functions. In this study, we compared the properties of the two cold-inducible RNA-binding proteins after ischemic stroke. Our results indicated that RBM3 expression was stimulated in the ischemic brain of stroke patients, while CIRP expression was not. In an experimental model, RBM3 can ameliorate ischemic-like insult by promoting neuronal survival and eliciting anti-inflammatory responses in activated microglia, while the impact of CIRP was intriguing. Collectively, our data supported the notion that RBM3 may be a more promising therapeutic target than CIRP for treating ischemic stroke. We further demonstrated that zr17-2, a small molecule initially identified to target CIRP, can specifically target RBM3 but not CIRP in microglia. zr17-2 demonstrated anti-inflammatory and neuroprotective effects after ischemic stroke both in vitro and in vivo, suggesting its potential therapeutic value.

Predictive value of serum interleukin-6 for neonatal encephalopathy outcomes

BACKGROUND

Serum interleukin-6 (IL-6) may predict adverse outcomes of neonatal encephalopathy (NE); however, limited data regarding the predictive utility of IL-6 during neurodevelopmental follow-up are available. We aimed to determine the utility of IL-6 for predicting adverse outcomes at 18 to 22 months of age.

METHODS

Eighty-seven patients with NE who received therapeutic hypothermia were enrolled in this study. Serial serum IL-6 levels during the first 3 postnatal days were collected. Patients were classified into three groups: 1) death, 2) survival with moderate to severe neurodevelopmental disability (NDD) at 18-22 months of age, and 3) survival without NDD (favorable outcome). The predictive ability of IL-6 was determined by the area under the receiver-operating characteristic curve (AUC).

RESULTS

Serial IL-6 data of 80 patients with NE were available and showed peak levels on postnatal day 1; these levels gradually decreased toward day 3. By 18-22 months of age, 13 and 17 patients died and experienced moderate to severe NDD without death, respectively. Fifty patients experienced favorable outcomes. Higher IL-6 levels on day 1 predicted the composite adverse outcome (including death and survival with NDD; n = 30; AUC, 0.648). Higher IL-6 levels on day 1 predicted death (n = 13; AUC, 0.799), whereas higher IL-6 levels on day 1 predicted survival with NDD (n = 17; AUC, 0.536).

CONCLUSIONS

The AUC of IL-6 that predicted survival with NDD was lower than the AUC of IL-6 that predicted death; therefore, IL-6 may have insufficient utility for predicting NDD without death.

Intranasal therapies for neonatal hypoxic-ischemic encephalopathy: Systematic review, synthesis, and implications for global accessibility to care

Neonatal hypoxic-ischemic encephalopathy (HIE) is the leading cause of neurodevelopmental morbidity in term infants worldwide. Incidence of HIE is highest in low and middle-income communities with minimal access to neonatal intensive care and an underdeveloped infrastructure for advanced neurologic interventions. Moreover, therapeutic hypothermia, standard of care for HIE in high resourced settings, is shown to be ineffective in low and middle-income communities. With their low cost, ease of administration, and capacity to potently target the central nervous system, intranasal therapies pose a unique opportunity to be a more globally accessible treatment for neonatal HIE. Intranasal experimental therapeutics have been studied in both rodent and piglet models, but no intranasal therapeutics for neonatal HIE have undergone human clinical trials. Additional research must be done to expand the array of treatments available for use as intranasal therapies for neonatal HIE thus improving the neurologic outcomes of infants worldwide.

Neonatal encephalopathy: a systematic review of reported treatment outcomes

BACKGROUND

Neonatal encephalopathy (NE) is a multi-organ condition potentially leading to death or long-term neurodisability. Therapeutic hypothermia is the standard treatment for NE; however, long-term impairments remain common. Studies of new treatments for NE often measure and report different outcomes. Core outcome sets (COSs), a minimum set of outcomes to be measured and reported in all studies for a condition, address this problem. This paper aimed to identify outcomes reported (primary, secondary, adverse events and other reported outcomes) in (1) randomised trials and (2) systematic reviews of randomised trials of interventions for the treatment of NE in the process of developing a COS for interventions for the treatment of NE.

METHODS

We completed a systematic search for outcomes used to evaluate treatments for NE using MEDLINE, Embase, Cochrane CENTRAL, the Cochrane Database of Systematic Reviews and the WHO International Clinical Trials Registry Platform. Two reviewers screened all included articles independently. Outcomes were extracted verbatim, similar outcomes were grouped and outcome domains were developed.

RESULTS

386 outcomes were reported in 116 papers, from 85 studies. Outcomes were categorised into 18 domains. No outcome was reported by all studies, a single study reported 11 outcomes and it was not explicitly stated that outcomes had input from parents.

DISCUSSION

Heterogeneity in reported outcomes means that synthesis of studies evaluating new treatments for NE remains difficult. A COS, that includes parental/family input, is needed to ensure consistency in measuring and reporting outcomes, and to enable comparison of randomised trials.

Validation of a machine learning algorithm for identifying infants at risk of hypoxic ischaemic encephalopathy in a large unseen data set

OBJECTIVE

To validate a hypoxic ischaemic encephalopathy (HIE) prediction algorithm to identify infants at risk of HIE immediately after birth using readily available clinical data.

DESIGN

Secondary review of electronic health record data of term deliveries from January 2017 to December 2021.

SETTING

A tertiary maternity hospital.

PATIENTS

Infants >36 weeks' gestation with the following clinical variables available: Apgar Score at 1 min and 5 min, postnatal pH, base deficit, and lactate values taken within 1 hour of birth INTERVENTIONS: Previously trained open-source logistic regression and random forest (RF) prediction algorithms were used to calculate a probability index (PI) for each infant for the occurrence of HIE.

MAIN OUTCOME

Validation of a machine learning algorithm to identify infants at risk of HIE in the immediate postnatal period.

RESULTS

1081 had a complete data set available within 1 hour of birth: 76 (6.95%) with HIE and 1005 non-HIE. Of the 76 infants with HIE, 37 were classified as mild, 29 moderate and 10 severe. The best overall accuracy was seen with the RF model. Median (IQR) PI in the HIE group was 0.70 (0.53-0.86) vs 0.05 (0.02-0.15), (p<0.001) in the non-HIE group. The area under the receiver operating characteristics curve for prediction of HIE=0.926 (0.893-0.959, p<0.001). Using a PI cut-off to optimise sensitivity of 0.30, 936 of the 1081 (86.5%) infants were correctly classified.

CONCLUSION

In a large unseen data set an open-source algorithm could identify infants at risk of HIE in the immediate postnatal period. This may aid focused clinical examination, transfer to tertiary care (if necessary) and timely intervention.

Developmental dyslexia in children with perinatal exposure to hypoxia: A systematic review

BACKGROUND

Research on a health-related event at the stage of labour and the occurrence of adverse outcomes at the school age has provided inconclusive results. Thus far, no systematic reviews have been conducted. Thus, the objective of this study is to investigate the association between hypoxia during pregnancy or delivery and the subsequent occurrence of a developmental dyslexia in school-age children.

METHODS

We used a standard search strategy of electronic databases (PubMed, PsycINFO, Web of Science, EMBASE, and Cochrane Library) and handsearching. We included observational studies (cohort studies, case-control studies) that consider as an exposure the presence of hypoxia during pregnancy or delivery, and as an outcome, developmental dyslexia in school-age children. Two reviewers independently conducted the search and determined eligibility, which was not restricted by language or year of publication.

RESULTS

The search took place until 1 April 2023. Of the 1,336 abstracts screened, 6 were assessed for eligibility. Of the six eligible studies, no studies met the pre-specified eligibly criteria.

CONCLUSIONS

We were unable to assess the association between hypoxia and developmental dyslexia, as no eligible studies were found. Thus, the association between hypoxia during pregnancy or delivery and dyslexia in school-age children remains unknown.

Neonatal encephalopathy due to suspected hypoxic ischemic encephalopathy: pathophysiology, current, and emerging treatments

BACKGROUND

Neonatal encephalopathy (NE) due to suspected hypoxic-ischemic encephalopathy (HIE), referred to as NESHIE, is a clinical diagnosis in late preterm and term newborns. It occurs as a result of impaired cerebral blood flow and oxygen delivery during the peripartum period and is used until other causes of NE have been discounted and HIE is confirmed. Therapeutic hypothermia (TH) is the only evidence-based and clinically approved treatment modality for HIE. However, the limited efficacy and uncertain benefits of TH in some low- to middle-income countries (LMICs) and the associated need for intensive monitoring have prompted investigations into more accessible and effective stand-alone or additive treatment options.

DATA SOURCES

This review describes the rationale and current evidence for alternative treatments in the context of the pathophysiology of HIE based on literatures from Pubmed and other online sources of published data.

RESULTS

The underlining mechanisms of neurotoxic effect, current clinically approved treatment, various categories of emerging treatments and clinical trials for NE are summarized in this review. Melatonin, caffeine citrate, autologous cord blood stem cells, Epoetin alfa and Allopurinal are being tested as potential neuroprotective agents currently.

CONCLUSION

This review describes the rationale and current evidence for alternative treatments in the context of the pathophysiology of HIE. Neuroprotective agents are currently only being investigated in high- and middle-income settings. Results from these trials will need to be interpreted and validated in LMIC settings. The focus of future research should therefore be on the development of inexpensive, accessible monotherapies and should include LMICs, where the highest burden of NESHIE exists.

Hypothermia for Hypoxic-ischemic Encephalopathy: Second-generation Trials to Address Gaps in Knowledge

Multiple randomized controlled trials of hypothermia for moderate or severe neonatal hypoxic-ischemic encephalopathy (HIE) have uniformly demonstrated a reduction in death or disability at early childhood evaluation. These initial trials along with other smaller studies established hypothermia as a standard of care in the neonatal community for moderate or severe HIE. The results of the initial trials have identified gaps in knowledge. This article describes 3 randomized controlled trials of hypothermia (second-generation trials) to address refinement of hypothermia therapy (longer and/or deeper cooling), late initiation of hypothermia (after 6 hours following birth), and use of hypothermia in preterm newborns.

Umbilical artery eucapnic pH to assess fetal well-being

BACKGROUND

Umbilical artery gas results help obstetricians assess fetal well-being during labor and guide screening decisions on eligibility for therapeutic hypothermia (ie, whole-body or head cooling). The accuracy of results, especially for the base deficit on arterial cord gas analysis, in predicting brain injury is questioned. A novel biomarker specifically calculated for fetal acid-base physiology and response to asphyxia-neonatal eucapnic pH as a marker of neonatal metabolic acidosis-has the potential to be an accurate predictor of hypoxic-ischemic encephalopathy.

OBJECTIVE

We aimed to compare false-negative rates of hypoxic-ischemic encephalopathy for umbilical artery pH, base deficit, and neonatal eucapnic pH in assessing fetal acid-base balance as a marker of fetal well-being and predicting acute brain injury.

STUDY DESIGN

This is a retrospective single-center cohort study of newborns ≥ 35 weeks of gestation diagnosed with hypoxic-ischemic encephalopathy. We compared false-negative rates for any grade of hypoxic-ischemic encephalopathy using unilateral paired chi-square statistical analysis based on cutoff values for umbilical artery pH ≤7.00, base deficit ≥16 mmol/L, base deficit ≥12 mmol/L and neonatal eucapnic pH ≤7.14. We performed an analysis of variance between umbilical artery pH, base deficit, and neonatal eucapnic pH for each hypoxic-ischemic encephalopathy grade.

RESULTS

We included 113 newborns. False-negative rate for hypoxic-ischemic encephalopathy was significantly higher for base deficit <16 mmol/L (n=78/113; 69.0%) than <12 mmol/L (n=46/113; 40.7%), pH >7.00 (n=41/113; 36.3%), or neonatal eucpanic pH >7.14 (n=35/113; 31.0%) (P<.0001). All true-positive cases were identified using only umbilical artery pH and neonatal eucapnic pH. Base deficit ≥16 or ≥12 mmol/L did not add any value in identifying newborns with hypoxic-ischemic encephalopathy when using umbilical artery pH and neonatal eucapnic pH. No association emerged between any marker and hypoxic-ischemic encephalopathy severity grading.

CONCLUSION

Our findings support the accuracy of neonatal eucapnic pH to assess fetal well-being during labor and to improve predictive performance for acute brain injury. Neonatal eucpanic pH, in addition to umbilical artery pH, may be a viable alternative in identifying newborns at risk for hypoxic-ischemic encephalopathy.

Long-Term Outcomes Following Hypoxic Ischemic Encephalopathy

Hypoxic ischemic encephalopathy (HIE) is the most common cause of neonatal encephalopathy and results in significant morbidity and mortality. Long-term outcomes of the condition encompass impairments across all developmental domains. While therapeutic hypothermia (TH) has improved outcomes for term and late preterm infants with moderate to severe HIE, trials are ongoing to investigate the use of TH for infants with mild or preterm HIE. There is no evidence that adjuvant therapies in combination with TH improve long-term outcomes. Numerous trials of various adjuvant therapies are underway in the quest to further improve outcomes for infants with HIE.

Single-Center Experience with Therapeutic Hypothermia for Hypoxic-Ischemic Encephalopathy in Infants with <36 Weeks' Gestation

OBJECTIVE

 Hypoxic-ischemic encephalopathy (HIE) is a leading cause of morbidity and mortality in neonates. Therapeutic hypothermia (TH) has improved outcomes and mortality in infants with >36 weeks' gestational age (GA) with moderate-to-severe HIE. There are limited data on the safety and efficacy of TH in preterm infants with HIE. This study describes our experience and examines the safety of TH in neonates with <36 weeks' GA.

STUDY DESIGN

A single-center, retrospective study of preterm neonates born at <36 weeks' GA with moderate-to-severe HIE and treated with TH, compared to a cohort of term neonates with HIE (≥37 weeks' GA), was conducted. The term cohort was matched for degree of background abnormality on electroencephalogram, sex, inborn versus outborn status, and birth year. Medical records were reviewed for pregnancy and delivery complications, need for transfusion, sedation and antiseizure medications, electroencephalography and imaging findings, and in-hospital mortality.

RESULTS

 Forty-two neonates born at <36 weeks' GA with HIE received TH between 2005 and 2022. Data from 42 term neonates were analyzed for comparison. The average GA of the preterm cohort was 34.6 weeks and 39.3 weeks for the term cohort. Apgar scores, degree of acidosis, and need for blood product transfusions were similar between groups. Preterm infants were more likely to require inotropic support (55 vs. 29%, p = 0.026) and hydrocortisone (36 vs. 12%, p = 0.019) for hypotension. The proportion of infants without evidence of injury on magnetic resonance imaging was similar in both groups: 43 versus 50% in preterm and term infants, respectively. No significant difference was found in mortality between groups.

CONCLUSION

 In this single-center cohort, TH in preterm infants appears to be as safe as in term infants, with no significant increase in intracranial bleeds or mortality. Preterm infants more frequently required inotropes and steroids for hypotension. Further research is needed to determine efficacy of TH in preterm infants.

KEY POINTS

· TH is used off-protocol in preterm infants.. · Preterm and term infants have similar mortality.. · Preterm cohort required more inotropic support..

Glucose instability and outcomes of neonates with hypoxic ischemic encephalopathy undergoing therapeutic hypothermia

BACKGROUND

To investigate the prevalence and associated outcomes of glucose abnormalities in infants with hypoxic ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH).

METHODS

Glucose values were reviewed in all HIE infants. Pearson's correlation was used to assess the association of hypo- and hyperglycemic episodes with neonatal brain MRI and neurodevelopmental outcomes (NDO) at 12 & 24 months.

RESULTS

Of 153 infants included, 31, 56 and 43 had episodes of hypo-, hyperglycemia and combined, respectively. Hyperglycemia and combined hypo/hyper had higher mortality (p = 0.035), seizures (p = 0.009), and longer hospitalization (p = 0.023). Hypo- and hyperglycemia were associated with parenchymal hemorrhages (p = 0.028 & p = 0.027, respectively). Hypoglycemia was associated with restricted diffusion (p = 0.014), while hyperglycemia was associated with cortical injuries (p = 0.045). Each hour of hyper- or hypoglycemia was associated with 5.2-5.8 times unfavorable outcomes (p < 0.001).

CONCLUSION

Blood glucose aberrations were detrimental in HIE infants treated with TH. Optimizing glucose management is crucial in this setting.

Communicating with Parents About Therapeutic Hypothermia and Hypoxic Ischemic Encephalopathy: Integrating a Palliative Care Approach into Practice

Parents of newborns with hypoxic ischemic encephalopathy (HIE) can face communication challenges in the neonatal intensive care unit. Both specialty palliative care and primary palliative care trained clinicians can assist parents as they navigate traumatic experiences and uncertain prognoses. Using evidence-based frameworks, the authors provide samples of how to communicate with parents and promote parent well-being across the care trajectory. The authors demonstrate how to involve parents in a shared decision-making process and give special consideration to the complexities of hospital discharge and the transition home. Sustained investment to guide the development of effective communication skills is crucial to support families of infants with HIE.

Acute kidney injury in neonates with hypoxic ischemic encephalopathy based on serum creatinine decline compared to KDIGO criteria

BACKGROUND

Neonates with hypoxic ischemic encephalopathy receiving therapeutic hypothermia (HIE + TH) are at risk for acute kidney injury (AKI). The standardized Kidney Disease Improving Global Outcomes (KDIGO) criteria identifies AKI based on a rise in serum creatinine (SCr) or reduced urine output. This definition is challenging to apply in neonates given the physiologic decline in SCr during the first week of life. Gupta et al. proposed alternative neonatal criteria centered on rate of SCr decline. This study aimed to compare the rate of AKI based on KDIGO and Gupta in neonates with HIE and to examine associations with mortality and morbidity.

METHODS

A retrospective review was performed of neonates with moderate to severe HIE + TH from 2008 to 2020 at a single center. AKI was assessed in the first 7 days after birth by KDIGO and Gupta criteria. Mortality, brain MRI severity of injury, length of stay, and duration of respiratory support were compared between AKI groups.

RESULTS

Among 225 neonates, 64 (28%) met KDIGO, 69 (31%) neonates met Gupta but not KDIGO, and 92 (41%) did not meet either definition. Both KDIGO-AKI and GuptaOnly-AKI groups had an increased risk of the composite mortality and/or moderate/severe brain MRI injury along with longer length of stay and prolonged duration of respiratory support compared to those without AKI.

CONCLUSIONS

AKI in neonates with HIE + TH was common and varied by definition. The Gupta definition based on rate of SCr decline identified additional neonates not captured by KDIGO criteria who are at increased risk for adverse outcomes. Incorporating the rate of SCr decline into the neonatal AKI definition may increase identification of clinically relevant kidney injury in neonates with HIE + TH.

Pipeline to Neonatal Clinical Transformation: The Importance of Preclinical Data

Historically, neonatal neuroscience boasted a robust and successful preclinical pipeline for therapeutic interventions, in particular for the treatment of hypoxic-ischemic encephalopathy (HIE). However, since the successful translation of therapeutic hypothermia (TH), several high-profile failures of promising adjunctive therapies, in addition to the lack of benefit of TH in lower resource settings, have brought to light critical issues in that same pipeline. Using recent data from clinical trials of erythropoietin as an example, the authors highlight several key challenges facing preclinical neonatal neuroscience for HIE therapeutic development and propose key areas where model development and collaboration across the field in general can ensure ongoing success in treatment development for HIE worldwide.

Short-Term Outcomes of Neonates with Hypoxic-Ischemic Encephalopathy Receiving Active Versus Passive Cooling During Transport

Therapeutic hypothermia (TH) is the only currently approved treatment for neonatal hypoxic-ischemic encephalopathy (HIE) and must be started within 6 hours to optimize effectiveness. This narrow therapeutic window often requires initiation of TH before or during transport. The goal of this study was to assess the effects of servo-controlled TH versus passive hypothermia during transport on short-term outcomes in newborns with HIE. This was a single-center retrospective case-control study of neonates with HIE treated with active or passive TH during transport. Primary outcomes included brain injury on magnetic resonance imaging (MRI) and presence of seizures. Seventy-six neonates were included-13 active and 63 passive. The active TH group was more likely to arrive within goal temperature. No difference was noted between groups in seizures or TH complications. Active TH was associated with increased injury on MRI. Active TH resulted in tighter temperature control, but no improvement in short-term outcomes in our cohort. The MRI findings may be due to differences in overall disease severity, which could not be adjusted for, given the modest sample size.

Short-term outcomes of asphyxiated neonates depending on requirement for transfer in the first 24 h of life

IMPORTANCE

In neonates with birth asphyxia (BA) and hypoxic-ischemic encephalopathy, therapeutic hypothermia (TH), initiated within six hours, is the only safe and established neuroprotective measure to prevent secondary brain injury. Infants born outside of TH centers have delayed access to cooling.

OBJECTIVE

To compare in-hospital mortality, occurrence of seizures, and functional status at discharge in newborns with BA depending on postnatal transfer for treatment to another hospital within 24 h of admission (transferred (TN) versus non-transferred neonates (NTN)).

DESIGN

Nationwide retrospective cohort study from a comprehensive hospital dataset using codes of the International Classification of Diseases, 10th modification (ICD-10). Clinical and outcome information was retrieved from diagnostic and procedural codes. Hierarchical multilevel logistic regression modeling was performed to quantify the effect of being postnatally transferred on target outcomes.

SETTING

All discharges from German hospitals from 2016 to 2021.

PARTICIPANTS

Full term neonates with birth asphyxia (ICD-10 code: P21) admitted to a pediatric department on their first day of life.

EXPOSURES

Postnatal transfer to a pediatric department within 24 h of admission to an external hospital.

MAIN OUTCOMES

In-hospital death; secondary outcomes: seizures and pediatric complex chronic conditions category (PCCC) ≥ 2.

RESULTS

Of 11,703,800 pediatric cases, 25,914 fulfilled the inclusion criteria. TNs had higher proportions of organ dysfunction, TH, organ replacement therapies, and neurological sequelae in spite of slightly lower proportions of maternal risk factors. In TNs, the adjusted odds ratios (OR) for death, seizures, and PCCC ≥ 2 were 4.08 ((95% confidence interval 3.41-4.89), 2.99 (2.65-3.38), and 1.76 (1.52-2.05), respectively. A subgroup analysis among infants receiving TH (n = 3,283) found less pronounced adjusted ORs for death (1.67 (1.29-2.17)) and seizures (1.26 (1.07-1.48)) and inverse effects for PCCC ≥ 2 (0.81 (0.64-1.02)) in TNs.

CONCLUSION AND RELEVANCE

This comprehensive nationwide study found increased odds for adverse outcomes in neonates with BA who were transferred to another facility within 24 h of hospital admission. Closely linking obstetrical units to a pediatric department and balancing geographical coverage of different levels of care facilities might help to minimize risks for postnatal emergency transfer and optimize perinatal care.

Moving the Needle in Low-Resource Settings: Is Hypothermia a Friend or a Foe?

Hypoxic-ischemic encephalopathy in low resource settings is associated with low occurrence of perinatal sentinel events, growth restriction, short birth depression, early seizure onset, white matter injury, and non-acute hypoxia on whole genome expression profile suggesting that intra-partum hypoxia might be occurring from a normal or augmented labor process in an already compromised fetus. Induced hypothermia increases mortality and does not reduce brain injury. Strict adherence to the updated National Neonatology forum guidelines is essential to prevent harm from induced hypothermia in low resource settings.

SMYD5 is a regulator of the mild hypothermia response

The mild hypothermia response (MHR) maintains organismal homeostasis during cold exposure and is thought to be critical for the neuroprotection documented with therapeutic hypothermia. To date, little is known about the transcriptional regulation of the MHR. We utilize a forward CRISPR-Cas9 mutagenesis screen to identify the histone lysine methyltransferase SMYD5 as a regulator of the MHR. SMYD5 represses the key MHR gene SP1 at euthermia. This repression correlates with temperature-dependent levels of histone H3 lysine 26 trimethylation (H3K36me3) at the SP1 locus and globally, indicating that the mammalian MHR is regulated at the level of histone modifications. We have identified 37 additional SMYD5-regulated temperature-dependent genes, suggesting a broader MHR-related role for SMYD5. Our study provides an example of how histone modifications integrate environmental cues into the genetic circuitry of mammalian cells and provides insights that may yield therapeutic avenues for neuroprotection after catastrophic events.

Blood glucose and β-hydroxybutyrate predict significant brain injury after hypoxia-ischemia in neonatal mice

BACKGROUND

The Vannucci procedure is widely used to model cerebral hypoxic-ischemic (HI) injury in neonatal rodents. Identifying minimally invasive biomarkers linked to brain injury would improve stratification of pups to experimental treatments. We hypothesized that extreme blood glucose (BG) and β-hydroxybutyrate (bHB) levels immediately after HI will correlate with severity of brain injury in this model.

METHODS

C57BL6 mice of both sexes underwent the Vannucci procedure with BG and bHB measured immediately after hypoxia. GFAP and α-fodrin were measured to assess injury severity at 4h, P11, P18 and P40. Open field (OF), Y-maze (YM), and Object-location task (OLT) were tested at P40.

RESULTS

Clinical seizures-like stereotypies during hypoxia were associated with lower post-hypoxia BG in HI-injured mice. Low BG after HI was related to higher GFAP expression, higher α-fodrin breakdown, lower residual regional volume, and worse working memory. BG was superior to bHB in ROC analysis with BG threshold of <111 mg/dL providing 100% specificity with 72% sensitivity for hippocampal HI-injury.

CONCLUSIONS

Post-hypoxic BG is a minimally invasive screening tool to identify pups with significant HI brain injury in the Vannucci model modified for mice improving our ability to stratify pups to experimental treatments to assess effectiveness.

IMPACT

End hypoxic-ischemic blood glucose levels are a reliable and inexpensive biomarker to detect hypoxic-ischemic brain injury in mice. Screening with blood glucose levels post-hypoxia allows appropriate stratification of those mouse pups most likely to be injured to experimental treatments improving validity and translatability of the results. These findings provide biological plausibility to the clinical observation that extreme blood glucose levels relate to worse outcomes after hypoxia-ischemia.

Methylxanthine use in infants with hypoxic-ischemic encephalopathy: a retrospective cohort study

Therapeutic hypothermia is the standard treatment for hypoxic-ischemic encephalopathy (HIE), but despite its widespread use, the rates of mortality and neurodevelopmental impairment for moderate to severe HIE remain around 30%. Methylxanthines, such as caffeine and aminophylline, have potential neuroprotective effects in the setting of hypoxic-ischemic injury. However, data on the safety and efficacy of methylxanthines in the setting of therapeutic hypothermia for HIE are limited. This retrospective multicenter study examined in-hospital outcomes in 52 infants with HIE receiving methylxanthines and therapeutic hypothermia. The frequency of mortality and in-hospital morbidities were similar to those of infants enrolled in clinical trials undergoing therapeutic hypothermia without adjunctive therapies. Clinical trials of methylxanthines for neuroprotection in HIE are needed to determine safety and efficacy and should explore optimal dosing and timing of methylxanthine administration.

Renal Regional Oxygen Saturation and Acute Kidney Injury in Neonates with Perinatal Asphyxia

OBJECTIVE

 Neonates with moderate-to-severe perinatal asphyxia often develop acute kidney injury (AKI). Additionally, therapeutic hypothermia (TH) can affect renal blood flow. This study aimed to evaluate the association between renal regional oxygen saturation (rSrO2) during TH and AKI in neonates with moderate and severe perinatal asphyxia.

STUDY DESIGN

 This retrospective longitudinal study included neonates with moderate-to-severe asphyxia who required TH. The primary outcome was the occurrence of AKI, classified as a rate of decrease in creatinine levels of <33% at 72 hours of TH. rSrO2 was continuously monitored by near-infrared spectroscopy during the hypothermia and rewarming phases. Data analysis involved dividing the average rSrO2 levels into 12-hour periods. We analyzed the association between AKI and rSrO2 levels using univariate and multivariate logistic regression models. Furthermore, we assessed the predictive capacity of rSrO2 for AKI by analyzing the area under the receiver operating characteristic curve.

RESULTS

 Ninety-one patients were included in the study. On average, patients with AKI exhibit lower rSrO2 levels during TH. Specifically, rSrO2 levels within the first 12 hours and between 25 and 72 hours of TH demonstrated the highest predictive capability for AKI. Multivariate logistic regression analysis revealed that rSrO2 levels within the initial 12 hours (adjusted odds ratio [aOR] = 1.11, 95% confidence interval [CI]: 1.01-1.21) and between 61 and 72 hours (aOR = 0.85, 95% CI: 0.78-0.92) were significantly associated with AKI.

CONCLUSION

 An increase in rSrO2 during the first 12 hours of TH and lower rSrO2 levels between 61 and 72 hours of treatment were associated with the development of AKI in asphyxiated neonates undergoing TH.

KEY POINTS

· Neonates with asphyxia often develop AKI.. · Renal saturations are affected by hypothermia and asphyxia. · Patients with AKI initially show higher rSrO2, then lower rSrO2.. · Monitoring rSrO2 identifies early AKI..

Cooling during transportation of newborns with hypoxic ischemic encephalopathy using phase change material mattresses in low-resource settings: a randomized controlled trial in Hanoi, Vietnam

OBJECTIVE

To determine the effectiveness of phase-change-material mattress (PCM) during transportation of newborns with hypoxic ischemic encephalopathy (HIE).

STUDY DESIGN

Randomized controlled trial of newborns with HIE from June 2016 to December 2019. Patients were randomized to transport with PCM or without PCM (control) when transferred to a cooling center in northern Vietnam. Primary outcome measure was mortality rate, secondary outcomes including temperature control and adverse effects.

RESULT

Fifty-Two patients in PCM-group and 61 in control group. Median rectal temperature upon arrival was 34.5 °C (IQR 33.5-34.8) in PCM-group and 35.1 °C (IQR 34.5-35.9) in control group (p = 0.023). Median time from birth to reach target temperature was 5.0 ± 1.4 h and 5.5 ± 1.2 h in the respective groups (p = 0.065). 81% of those transported with PCM versus 62% of infants transported without (p = 0.049) had reached target temperature within the 6-h timeframe. There was no record of overcooling (< 32 °C) in any of the groups. The was no difference in mortality rate between the two groups (33% and 34% respectively (p > 0.05)).

CONCLUSION

Phase-change-material can be used as a safe and effective cooling method during transportation of newborns with HIE in low-resource settings.

TRIAL REGISTRATION

The study was retro-prospectively registered in Clinical Trials (04/05/2022, NCT05361473).

Thermoregulated transcriptomics: the molecular basis and biological significance of temperature-dependent alternative splicing

Temperature-dependent alternative splicing (AS) is a crucial mechanism for organisms to adapt to varying environmental temperatures. In mammals, even slight fluctuations in body temperature are sufficient to drive significant AS changes in a concerted manner. This dynamic regulation allows organisms to finely tune gene expression and protein isoform diversity in response to temperature cues, ensuring proper cellular function and physiological adaptation. Understanding the molecular mechanisms underlying temperature-dependent AS thus provides valuable insights into the intricate interplay between environmental stimuli and gene expression regulation. In this review, we provide an overview of recent advances in understanding temperature-regulated AS across various biological processes and systems. We will discuss the machinery sensing and translating temperature cues into changed AS patterns, the adaptation of the splicing regulatory machinery to extreme temperatures, the role of temperature-dependent AS in shaping the transcriptome, functional implications and the development of potential therapeutics targeting temperature-sensitive AS pathways.

Slow rewarming after hypothermia does not ameliorate white matter injury after hypoxia-ischemia in near-term fetal sheep

BACKGROUND

The optimal rate to rewarm infants after therapeutic hypothermia is unclear. In this study we examined whether slow rewarming after 72 h of hypothermia would attenuate white matter injury.

METHODS

Near-term fetal sheep received sham occlusion (n = 8) or cerebral ischemia for 30 min, followed by normothermia (n = 7) or hypothermia from 3-72 h, with either spontaneous fast rewarming (n = 8) within 1 h, or slow rewarming at ~0.5 °C/h (n = 8) over 10 h. Fetuses were euthanized 7 days later.

RESULTS

Ischemia was associated with loss of total and mature oligodendrocytes, reduced expression of myelin proteins and induction of microglia and astrocytes, compared with sham controls (P < 0.05). Both hypothermia protocols were associated with a significant increase in numbers of total and mature oligodendrocytes, area fraction of myelin proteins and reduced numbers of microglia and astrocytes, compared with ischemia-normothermia (P < 0.05). There was no difference in the number of oligodendrocytes, microglia or astrocytes or expression of myelin proteins between fast and slow rewarming after hypothermia.

CONCLUSION

The rate of rewarming after a clinically relevant duration of hypothermia had no apparent effect on white matter protection by hypothermia after cerebral ischemia in near-term fetal sheep.

IMPACT

Persistent white matter injury is a major contributor to long-term disability after neonatal encephalopathy despite treatment with therapeutic hypothermia. The optimal rate to rewarm infants after therapeutic hypothermia is unclear; current protocols were developed on a precautionary basis. We now show that slow rewarming at 0.5 °C/h did not improve histological white matter injury compared with rapid spontaneous rewarming after a clinically established duration of hypothermia in near-term fetal sheep.

Standardizing neonatal hypoxic ischemic encephalopathy evaluation and documentation practices

BACKGROUND

Infants at risk for hypoxic ischemic encephalopathy (HIE) require a time sensitive evaluation and decision-making regarding treatment with therapeutic hypothermia (TH). Prior to this project, there was no standardized approach to evaluating these infants locally.

METHODS

Included infants were "at risk for HIE," defined as meeting the "patient characteristics" and "biochemical criteria" per the institutional HIE pathway. Our primary outcome was documentation of an HIE therapeutic hypothermia evaluation (HIETHE) within the first six hours of life which included: (1) recognition of at-risk status, (2) an encephalopathy exam, and (3) a decision regarding TH. Plan-Do-Study-Act cycles included novel clinical decision support.

RESULTS

From October 2020 to May 2023, among infants at-risk for HIE, the average percentage with an HIETHE documented improved from 47% to 82%.

CONCLUSIONS

We standardized the approach to infants at risk for HIE and improved the presence of a complete and timely evaluation regarding TH eligibility.

Association between Early Basal Ganglia and Thalami Perfusion Assessed by Color Doppler Ultrasonography and Brain Injury in Infants with Hypoxic-Ischemic Encephalopathy: A Prospective Cohort Study

OBJECTIVE

To evaluate associations between neurologic outcomes and early measurements of basal ganglia (BG) and thalamic (Th) perfusion using color Doppler ultrasonography (CDUS) in infants with hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

Prospective study of infants with mild (n = 18), moderate (n = 17), and severe HIE (n = 14) and controls (n = 17). Infants with moderate-severe HIE received therapeutic hypothermia (TH). CDUS was performed at 24-36 hours and brain magnetic resonance imaging (MRI) at a median of 10 days. Development was followed through 2.5-5 years. The primary outcome was the association between BG and Th perfusion and brain MRI injury. Secondary analyses focused on associations between perfusion measurements and admission neurologic examinations, MRI scores in infants treated with TH, and motor and sensory disability, or death. An exploratory analysis assessed the accuracy of BG and Th perfusion to predict brain MRI injury in infants treated with TH.

RESULTS

Increased BG and Th perfusion on CDUS was observed in infants with severe MRI scores and those with significant motor and neurosensory disability or death through 2.5-5 years (P < .05). Infants with severe HIE showed increased BG and Th perfusion (P < .005) compared with infants with moderate HIE. No differences were identified between the between the control and mild HIE groups. Th perfusion ≥0.237 cm/second (Area under the curve of 0.824) correctly classified 80% of infants with severe MRI scores.

CONCLUSIONS

Early dynamic CDUS of the BG and Th is a potential biomarker of severe brain injury in infants with HIE and may be a useful adjunct to currently used assessments.

Amplitude-Integrated Electroencephalography: A Readily Available Tool for Neonatologists

Hypoxic-ischemic encephalopathy (HIE) is a common condition occurring at birth, impairing central nervous system function. Therapeutic hypothermia is beneficial for suspected HIE as it reduces mortality and disability in survivors but not for other types of encephalopathy (e.g., metabolic). Amplitude-integrated electroencephalography (aEEG) complements limited resource Neonatal Intensive Care Units as a screening tool that can provide information regarding the degree of encephalopathy and electrographic seizures. Patients with HIE are at increased risk for seizures, which are subclinical in half of the cases. The aEEG emphasizes electroencephalographic amplitude differences, whereas continuous video electroencephalography (cEEG) provides a high-resolution picture of cerebral electrical activity, making it the most accurate method for detecting subclinical seizures. Still, its interpretation demands extensive training beyond the scope of neonatologists. Any infant in whom aEEG is suspicious for seizures should undergo cEEG to confirm the findings because even very low-amplitude artifacts might be misdiagnosed as seizures. We report a case and review the utility of aEEG in detecting subclinical seizures in neonates with HIE during therapeutic hypothermia while cEEG is not available.

Neonatal therapeutic hypothermia in a regional swedish cohort: Adherence to guidelines, transport and outcomes

AIM

Swedish guidelines for therapeutic hypothermia (TH) after perinatal asphyxia were established in 2007, following several randomised studies that demonstrated improved outcomes. We assessed the implementation of hypothermia treatment in a mid-Swedish region with a sizeable proportion of outborn infants.

METHOD

A population-based TH cohort from 2007 to 2015 was scrutinised for adherence to national guidelines, interhospital transport, including the use of a cooling mattress made of phase change material for thermal management, and outcomes.

RESULTS

Of 136 admitted infants, 99 (73 %) were born outside the hospital. Ninety-eight percent fulfilled the criteria for postnatal depression/acidosis, and all patients had moderate-to-severe encephalopathy. Treatment was initiated within 6 h in 85 % of patients; amplitude-integrated electroencephalography/electroencephalography was recorded in 98 %, cranial ultrasound in 78 %, brain magnetic resonance imaging in 79 %, hearing tests in all, and follow-up was performed in 93 %. Although target body temperature was attained later (p < 0.01) in outborn than in inborn infants, at a mean (standard deviations) age of 6.2 (3.2) h vs 4.4 (2.6) h, 40 % of those transported using the cooling mattress were already within the therapeutic temperature range on arrival, and few were excessively cooled. The mortality rate was 23 %, and 38 % of the survivors had neurodevelopmental impairment at a median of 2.5 years.

CONCLUSION

The regionalisation of TH, including interhospital transport, was feasible and resulted in outcomes comparable to those of randomised controlled studies.

Umbilical Cord pH Levels and Neonatal Morbidity and Mortality

Importance

Umbilical cord pH (UC-pH) level is an important objective indicator of intrapartum fetal hypoxia and is used to predict neonatal morbidity and mortality. A UC-pH value of less than 7.00 is often defined as a threshold for severe acidosis, but existing evidence is divergent and largely based on UC-pH measurements from selected populations; consequently, the results are challenging to interpret.

Objective

To investigate the association between UC-pH levels and the risk of adverse neonatal outcomes in a national setting with universal UC-pH measurement.

Design, Setting, and Participants

This national, population-based cohort study included all liveborn, singleton, full-term infants without malformations born in Denmark from January 1, 2012, to December 31, 2018. Data were analyzed from January 1, 2023, to March 1, 2024.

Exposure

Umbilical cord pH level categorized as less than 7.00, 7.00 to 7.09, 7.10 to 7.19 and 7.20 to 7.50 (reference group).

Main Outcomes and Measures

The primary outcome was a composite of severe adverse neonatal outcomes: neonatal death, therapeutic hypothermia, mechanical ventilation, treatment with inhaled nitric oxide, or seizures. Secondary outcomes were individual components of the primary outcome, Apgar score, respiratory outcomes, and hypoglycemia. Data are presented as adjusted risk ratios (ARRs) with 95% CIs.

Results

Among the 340 431 infants included, mean (SD) gestational age was 39.9 (1.6) weeks; mean (SD) birth weight was 3561 (480) g; and 51.3% were male. Umbilical cord pH of less than 7.20 was observed more often among infants with a gestational age of 40 or 41 weeks (31.6%-33.6% compared with 18.2%-20.2% at a gestational age of 39 weeks) and among male infants (53.9%-55.4% vs 44.6%-46.1% among female infants). Compared with the pH reference group (576 of 253 540 [0.2%]), the risk for the primary outcome was increased for the groups with UC-pH levels of less than 7.00 (171 of 1743 [9.8%]), 7.00 to 7.09 (101 of 11 904 [0.8%]), and 7.10 to 7.19 (259 of 73 244 [0.4%]). Comparable patterns were observed for the individual outcomes, except for neonatal death, which was only increased in the group with UC-pH levels of less than 7.10. The risk of treatment with continuous positive airway pressure was increased when UC-pH levels were less than 7.20, and the risk of hypoglycemia was 21.5% if UC-pH levels were less than 7.10.

Conclusions and Relevance

In this cohort study of 340 431 newborn infants, results support and extend previous studies indicating a higher risk of adverse outcomes even at UC-pH levels above 7.00. The threshold for more intensive observation and treatment may be reconsidered.

Prognostic value of quantitative EEG in early hours of life for neonatal encephalopathy and neurodevelopmental outcomes

BACKGROUND

The ability to determine severity of encephalopathy is crucial for early neuroprotective therapies and for predicting neurodevelopmental outcome. The objective of this study was to assess a novel brain state of newborn (BSN) trend to distinguish newborns with presence of hypoxic ischemic encephalopathy (HIE) within hours after birth and predict neurodevelopmental outcomes at 2 years of age.

METHOD

This is a prospective cohort study of newborns at 36 weeks' gestation or later with and without HIE at birth. The Total Sanart Score (TSS) was calculated based on a modified Sarnat exam within 6 h of life. BSN was calculated from electroencephalogram (EEG) measurements initiated after birth. The primary outcome at 2 year of age was a diagnosis of death or disability using the Bayley Scales of Infant Development III.

RESULTS

BSN differentiated between normal and abnormal neurodevelopmental outcomes throughout the entire recording period from 6 h of life. Additionally, infants with lower BSN values had higher odds of neurodevelopmental impairment and HIE. BSN distinguished between normal (n = 86) and HIE (n = 46) and showed a significant correlation with the concomitant TSS.

CONCLUSION

BSN is a sensitive real-time marker for monitoring dynamic progression of encephalopathy and predicting neurodevelopmental impairment.

IMPACT

This is a prospective cohort study to investigate the ability of brain state of newborn (BSN) trend to predict neurodevelopmental outcome within the first day of life and identify severity of encephalopathy. BSN predicts neurodevelopmental outcomes at 2 years of age and the severity of encephalopathy severity. It also correlates with the Total Sarnat Score from the modified Sarnat exam. BSN could serve as a promising bedside trend aiding in accurate assessment and identification of newborns who may benefit from additional neuroprotection therapies.

Growth trajectories and need for oral feeding support among infants with neonatal encephalopathy treated with therapeutic hypothermia

OBJECTIVE

Identify feeding supports required among infants with neonatal encephalopathy and determine growth trajectories to 3 years.

STUDY DESIGN

Single-center retrospective cohort study of 120 infants undergoing therapeutic hypothermia. Logistic regression and stratified analyses identified whether clinical factors, EEG-determined encephalopathy severity, and MRI-based brain injury predict feeding supports (nasogastric tube, oral feeding compensations) and growth.

RESULTS

50.8% of infants required feeding supports in the hospital, decreasing to 14% at discharge. Moderate-to-severe encephalopathy and basal ganglia injury predicted feeding support needs. Yet, 35% of mildly encephalopathic infants required gavage tubes. Growth trajectories approximated expected growth of healthy infants.

CONCLUSION

Infants with neonatal encephalopathy-even if mild-frequently experience feeding difficulties during initial hospitalization. With support, most achieve full oral feeds by discharge and adequate early childhood growth. Clinical factors may help identify infants requiring feeding support, but do not detect all at-risk infants, supporting routine screening of this high-risk population.

Identification and analysis of oxidative stress-related genes in hypoxic-ischemic brain damage using bioinformatics and experimental verification

BACKGROUND

Oxidative stress (OS) plays a major role in the progress of hypoxic-ischemic brain damage (HIBD). This study aimed to investigate OS-related genes and their underlying molecular mechanisms in neonatal HIBD.

METHODS

Microarray data sets were acquired from the Gene Expression Omnibus (GEO) database to screen the differentially expressed genes (DEGs) between control samples and HIBD samples. OS-related genes were drawn from GeneCards and OS-DEGs in HIBD were obtained by intersecting with the DEGs. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) were conducted to determine the underlying mechanisms and functions of OS-DEGs in HIBD. Moreover, the hub genes were screened using the protein-protein interaction network and identified in the GSE144456 data set. CIBERSORT was then performed to evaluate the expression of immunocytes in each sample and perform a correlation analysis of the optimal OS-DEGs and immunocytes. Finally, quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunohistochemistry were performed to validate the expression levels of the optimal OS-DEGs.

RESULTS

In total, 93 OS-DEGs were identified. GO, KEGG, and GSEA enrichment analyses indicated that these genes were predominantly enriched in OS and inflammation. Four OS-related biomarker genes (Jun, Fos, Tlr2, and Atf3) were identified and verified. CIBERSORT analysis revealed the dysregulation of six types of immune cells in the HIBD group. Moreover, 47 drugs that might target four OS-related biomarker genes were screened. Eventually, RT-qPCR and immunohistochemistry results for rat samples further validated the expression levels of Fos, Tlr2, and Atf3.

CONCLUSIONS

Fos, Tlr2 and Atf3 are potential OS-related biomarkers of HIBD progression. The mechanisms of OS are associated with those of neonatal HIBD.