Perinatal asphyxia: a review from a metabolomics perspective

Metabolomics analysis revealed the neuroprotective role of 2-phosphoglyceric acid in hypoxic-ischemic brain damage through GPX4/ACSL4 axis regulation

Hypoxic-ischemic brain damage (HIBD) is a cerebral injury resulting from the combination of ischemia and hypoxia in neonatal brain tissue. Presently, there exists no efficacious remedy for HIBD. A mounting body of evidence indicates that dynamic metabolites formed during metabolic procedures assume a vital role in neuronal maturation and recuperation. However, it remains unclear whether any endogenous metabolites are involved in the pathogenesis of HIBD. Here, an untargeted metabolomics analysis was conducted by gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry (GC/LC-MS) in OGD/R (oxygen-glucose deprivation/reoxygenation)-induced HT-22 cells. We observed that ferroptosis signaling plays an essential role in HI-induced neuronal injury. Interestingly, we also found that the differentially expressed metabolite, 2-phosphoglyceric acid, significantly improved the neuronal cell survival of OGD/R HT-22 cells by inhibiting ferroptosis. Moreover, 2-phosphoglyceric acid effectively rescued the cell activity of HT-22 cells treated with the ferroptosis inducer RSL-3. Furthermore, 2-phosphoglyceric acid alleviated cerebral infarction and reduced HIBD-induced neuronal cell loss of the central nervous system in neonatal rats by regulating GPX4 expression. Taken together, we found that 2-phosphoglyceric acid, which was downregulated in HT-22 cells induced by OGD/R, exerted neuronal protective effects on OGD/R-treated HT-22 cells and HIBD-induced neonatal rats by inhibiting hypoxic-ischemic-induced ferroptosis through the regulation of the GPX4/ACSL4 axis.

Development and Characterization of Interstitial-Fluid-Mimicking Solutions for Pre-Clinical Assessment of Hypoxia

Asphyxia, a leading cause of illness and death in newborns, can be improved by early detection and management. Arterial blood gas (ABG) analysis is commonly used to diagnose and manage asphyxia, but it is invasive and carries risks. Dermal interstitial fluid (ISF) is an alternative physiological fluid that can provide valuable information about a person's health. ISF is more sensitive to severe hypoxia and metabolic disorders compared to blood, making it an attractive option for minimally invasive asphyxia detection using biosensors. However, obtaining ISF samples from humans is challenging due to ethical concerns and sampling difficulties. To address this, researchers are developing ISF-mimicking solutions as substitutes for early testing and evaluation of biosensors. This paper focuses on the development of these solutions for bench-based testing and validation of continuous asphyxia-monitoring biosensors. With an understanding of the factors influencing system quality and performance, these solutions can aid in the design of biosensors for in vivo monitoring of dermal ISF. Monitoring interstitial fluid pH levels can provide valuable insights into the severity and progression of asphyxia, aiding in accurate diagnosis and informed treatment decisions. In this study, buffer solutions were prepared to mimic the pH of ISF, and their electrical properties were analyzed. The results suggest that certain buffers can effectively mimic metabolic acidosis associated with asphyxia (pH < 7.30), while others can mimic metabolic alkalosis (pH > 7.45). Overall, this research contributes to the development of ISF-mimicking solutions and lays the groundwork for biosensor systems that monitor dermal ISF in real time.

Birth asphyxia and its associated factors among newborns at a tertiary hospital: evidence from Southern Ethiopia

Background

Globally, 45% of under-five children death occurs during the neonatal period and about 25% of all neonatal deaths are caused by birth asphyxia. In Ethiopia, in 2015, it was the first cause of neonatal deaths followed by prematurity and sepsis. The study aims to assess prevalence of Birth asphyxia and associated factors.

Methods

Institution-based cross-sectional study was conducted among neonates admitted to Neonatal intensive care unit of Hawassa University Specialized comprehensive hospital from December 1 to December 30, 2020. Systematic random sampling technique was employed to select samples. Logistic regression analysis using Statistical Package for Social sciences version 24was employed.

Results

The prevalence of neonatal asphyxia in this study was17.9%. Prolonged labor [AOR (Adjusted odds ration) = 2.909; (95% CI (Confidence Interval): 1.184 - 7.151)], presence of meconium [AOR= 2.137; 95% CI 1.028 - 4.683)], premature rapture of membrane [AOR = 2.459; 95% CI: 1.021 - 6.076)] and complication during labor [AOR= 3.351; 95% CI: 2.142-5.871))], were factors associated with neonatal asphyxia.

Conclusion and Recommendations

Nearly two in every ten newborns faced perinatal asphyxia in the study area. Early identification of high-risk women, intervening on delay in referral, and early and vigorous management of abnormal labor and complicated labor is essential to halt the problem.

Diagnostic Value and Prognostic Significance of Nucleated Red Blood Cells (NRBCs) in Selected Medical Conditions

Nucleated red blood cells (NRBCs) are premature erythrocyte precursors that reside in the bone marrow of humans of all ages as an element of erythropoiesis. They rarely present in healthy adults' circulatory systems but can be found circulating in fetuses and neonates. An NRBC count is a cost-effective laboratory test that is currently rarely used in everyday clinical practice; it is mostly used in the diagnosis of hematological diseases/disorders relating to erythropoiesis, anemia, or hemolysis. However, according to several studies, it may be used as a biomarker in the diagnosis and clinical outcome prognosis of preterm infants or severely ill adult patients. This would allow for a quick diagnosis of life-threatening conditions and the prediction of a possible change in a patient's condition, especially in relation to patients in the intensive care unit. In this review, we sought to summarize the possible use of NRBCs as a prognostic marker in various disease entities. Research into the evaluation of the NRBCs in the pediatric population most often concerns neonatal hypoxia, the occurrence and consequences of asphyxia, and overall neonatal mortality. Among adults, NRBCs can be used to predict changes in clinical condition and mortality in critically ill patients, including those with sepsis, trauma, ARDS, acute pancreatitis, or severe cardiovascular disease.

Henriques T. Machine learning models based on clinical indices and cardiotocographic features for discriminating asphyxia fetuses—Porto retrospective intrapartum study

Introduction

Perinatal asphyxia is one of the most frequent causes of neonatal mortality, affecting approximately four million newborns worldwide each year and causing the death of one million individuals. One of the main reasons for these high incidences is the lack of consensual methods of early diagnosis for this pathology. Estimating risk-appropriate health care for mother and baby is essential for increasing the quality of the health care system. Thus, it is necessary to investigate models that improve the prediction of perinatal asphyxia. Access to the cardiotocographic signals (CTGs) in conjunction with various clinical parameters can be crucial for the development of a successful model.

Objectives

This exploratory work aims to develop predictive models of perinatal asphyxia based on clinical parameters and fetal heart rate (fHR) indices.

Methods

Single gestations data from a retrospective unicentric study from Centro Hospitalar e Universitário do Porto de São João (CHUSJ) between 2010 and 2018 was probed. The CTGs were acquired and analyzed by Omniview-SisPorto, estimating several fHR features. The clinical variables were obtained from the electronic clinical records stored by ObsCare. Entropy and compression characterized the complexity of the fHR time series. These variables' contribution to the prediction of asphyxia perinatal was probed by binary logistic regression (BLR) and Naive-Bayes (NB) models.

Results

The data consisted of 517 cases, with 15 pathological cases. The asphyxia prediction models showed promising results, with an area under the receiver operator characteristic curve (AUC) &gt;70%. In NB approaches, the best models combined clinical and SisPorto features. The best model was the univariate BLR with the variable compression ratio scale 2 (CR2) and an AUC of 94.93% [94.55; 95.31%].

Conclusion

Both BLR and Bayesian models have advantages and disadvantages. The model with the best performance predicting perinatal asphyxia was the univariate BLR with the CR2 variable, demonstrating the importance of non-linear indices in perinatal asphyxia detection. Future studies should explore decision support systems to detect sepsis, including clinical and CTGs features (linear and non-linear).

Childhood Obesity and the Cryptic Language of the Microbiota: Metabolomics’ Upgrading

The growing obesity epidemic in childhood is increasingly concerning for the related physical and psychological consequences, with a significant impact on health care costs in both the short and the long term. Nonetheless, the scientific community has not yet completely clarified the complex metabolic mechanisms underlying body weight alterations. In only a small percentage of cases, obesity is the result of endocrine, monogenic, or syndromic causes, while in much more cases, lifestyle plays a crucial role in obesity development. In this context, the pediatric age appears to be of considerable importance as prevention strategies together with early intervention can represent important therapeutic tools not only to counteract the comorbidities that increasingly affect children but also to hinder the persistence of obesity in adulthood. Although evidence in the literature supporting the alteration of the microbiota as a critical factor in the etiology of obesity is abundant, it is not yet fully defined and understood. However, increasingly clear evidence is emerging regarding the existence of differentiated metabolic profiles in obese children, with characteristic metabolites. The identification of specific pathology-related biomarkers and the elucidation of the altered metabolic pathways would therefore be desirable in order to clarify aspects that are still poorly understood, such as the consequences of the interaction between the host, the diet, and the microbiota. In fact, metabolomics can characterize the biological behavior of a specific individual in response to external stimuli, offering not only an eventual effective screening and prevention strategy but also the possibility of evaluating adherence and response to dietary intervention.

Comparison of new biomarkers in the diagnosis of perinatal asphyxia

Objectives

Precise and early diagnosis of neonatal asphyxia may improve outcomes. Recent studies aim to identify diagnostic biomarkers in neonates at risk for brain damage. The current study was designed to evaluate the diagnostic value of new biomarkers for neonatal asphyxia.

Materials & Methods

This prospective study was conducted with an available sampling of infants upper 35 weeks of gestational age, including neonates with asphyxia (case group) and healthy controls, 2014-2022, in Ghaem Hospital, Mashhad, Iran. Data collection was performed utilizing a researcher-made questionnaire, including maternal and neonatal characteristics, as well as clinical and laboratory evaluation. Serum umbilical cord levels of interleukin-6 (IL6), interleukin-1-beta (IL- 1β), pro-oxidant-antioxidant balance (PAB), and heat shock protein-70 (HSP70), as well as nucleated red blood cells count (NRBC), were determined. Data were analyzed by t-test, Chi-square, receiver operating characteristic (ROC), and regression models.

Results

The differences in variables IL6, IL1β, PAB, NRBC/100WBC, and HSP70 were statistically significant between the two groups (in all cases, P<0.0001). In the diagnosis of asphyxia, the most sensitive marker (89%) was IL1β more than 2.39 pg/ml and HSP 70 upper than 0.23 ng/ml, while IL6 was higher than 9pg/ml, determined as the most specific marker (85%). Furthermore, a combination of HSP + PAB and IL6 + lL1b + PAB + NRBC/100WBC possesses the prediction power of 93.2% and 87.3%, respectively, for diagnosing asphyxia.

Conclusion

According to data analysis, the combination of new biochemical markers (NRBC count, IL6, IL1β, PAB, and HSP 70) could be a reliable marker for diagnosing infants with asphyxia.

Two Useful Umbilical Biomarkers for Therapeutic Hypothermia Decision in Patients with Hypoxic İschemic Encephalopathy with Perinatal Asphyxia: Netrin-1 and Neuron Specific Enolase

Hypoxic-ischemic encephalopathy (HIE) has a high risk of mortality in addition to serious neurological damage. In this study, we investigated the values of umbilical cord netrin-1 (NT-1) and neuron specific enolase (NSE) levels in the early diagnosis of HIE stage II/III induced by neonatal asphyxia. In the study group, infants with gestational age ≥ 36 weeks who were diagnosed with HIE II/III were included. NT-1 and NSE levels were measured from the umbilical cord immediately after birth. Results were compared between HIE II/III and the healthy control group. Cutoff values for serum NT-1 and NSE were determined with receiver-operating characteristics curves and the area under the curve (AUC) was used to determine the diagnostic value of NT-1 and NSE levels in infants diagnosed with HIE II/III. NT-1 (358.3 ± 108.3 pg/mL) and NSE (52.97 ± 17.8 ng/mL) levels in the cord blood in the HIE group were significantly higher (p = .030, p = .001, respectively) than cord blood values in the control group (NT-1 (275.1 ± 84.6 pg/mL) and NSE (28.7 ± 16.3 ng/mL)). NT-1 cutoff value for HIE was 292.3 pg/mL and 34.7 ng/mL for NSE (AUC: 990, sensitivity: 94%, specificity 100% and AUC: 1.0, sensitivity: 100% vs. specificity 100%, respectively). NT-1 and NSE represent candidate biomarkers with high reliability in the prediction in newborns with moderate-to-severe HIE.

Resuscitation of Term Compromised and Asphyctic Newborns: Better with Intact Umbilical Cord?

The authors hypothesize that particularly severely compromised and asphyctic term infants in need of resuscitation may benefit from delayed umbilical cord clamping (after several minutes). Although evidence is sparse, the underlying pathophysiological mechanisms support this assumption. For this review the authors have analyzed the available research. Based on these data they conclude that it may be unfavorable to immediately clamp the cord of asphyctic newborns (e.g., after shoulder dystocia) although recommended in current guidelines to provide quick neonatological support. Compression of the umbilical cord or thorax obstructs venous flow to the fetus more than arterial flow to the placenta. The fetus is consequently cut off from a supply of oxygenated, venous blood. This may cause not only hypoxemia and consecutive hypoxia during delivery but possibly also hypovolemia. Immediate cord clamping may aggravate the situation of the already compromised newborn, particularly if the cord is cut before the lungs are ventilated. By contrast, delayed cord clamping leads to fetoplacental transfusion of oxygenated venous blood, which may buffer an existing acidosis. Furthermore, it may enhance blood volume by up to 20%, leading to higher levels of various blood components, such as red and white blood cells, thrombocytes, mesenchymal stem cells, immunoglobulins, and iron. In addition, the resulting increase in pulmonary perfusion may compensate for an existing hypoxemia or hypoxia. Early cord clamping before lung perfusion reduces the preload of the left ventricle and hinders the establishment of sufficient circulation. Animal models and clinical trials support this opinion. The authors raise the question whether it would be better to resuscitate compromised newborns with intact umbilical cords. Obstetric and neonatal teams need to work even closer together to improve neonatal outcomes.

Risk Factors of Birth Asphyxia among Newborns at Debre Markos Comprehensive Specialized Referral Hospital, Northwest Ethiopia: Unmatched Case-Control Study

Background

Despite a global decline in under-five deaths, the neonatal mortality rate remains slow in developing countries and birth asphyxia remains the third cause of neonatal deaths. Globally, neonatal deaths accounts for 45% of under-five deaths, birth asphyxia causes 23-40% of neonatal deaths in Ethiopia. There is limited data on risk factors of asphyxia in Ethiopia, particularly in the study area. Therefore, this study aimed to identify the risk factors of birth asphyxia among newborns.

Methods

This research followed a hospital-based unmatched case-control study design at Debre Markos comprehensive specialized referral hospital, Northwest Ethiopia, among 372 newborns (124 cases and 248 controls). Data were collected by interviewing index mothers and chart review using a pre-tested questionnaire. Then it was entered in Epi-data version 3.1 and transferred to STATA version 14.0 for analysis. Bivariate and multiple variable logistic regression were carried out to the possible risk factors. Finally, statistical significance was declared using adjusted odds ratio with 95% CI and p-value <0.05.

Results

Prolonged labor >12, meconium-stained amniotic fluid, assisted vaginal delivery, gestational age < 37 weeks, noncephalic presentation, comorbidity, birthweight<2500grams were found to be significant factors of birth asphyxia.

Conclusion

In this study, Prolonged labor >12 hours, meconium-stained amniotic fluid, assisted vaginal delivery, gestational age < 37 weeks, non-cephalic presentation comorbidity, fetal distress, birthweight<2500grams were found to be risk factors of birth asphyxia were risk factors of birth asphyxia. Therefore, to reduce neonatal mortality associated with birth asphyxia, attention should be given to holistic pregnancy, labor and delivery care, and post-natal care. Moreover, interventions aimed at reducing birth asphyxia should target the identified factors.

Pathophysiology of Perinatal Asphyxia in Humans and Animal Models

Perinatal asphyxia is caused by lack of oxygen delivery (hypoxia) to end organs due to an hypoxemic or ischemic insult occurring in temporal proximity to labor (peripartum) or delivery (intrapartum). Hypoxic-ischemic encephalopathy is the clinical manifestation of hypoxic injury to the brain and is usually graded as mild, moderate, or severe. The search for useful biomarkers to precisely predict the severity of lesions in perinatal asphyxia and hypoxic-ischemic encephalopathy (HIE) is a field of increasing interest. As pathophysiology is not fully comprehended, the gold standard for treatment remains an active area of research. Hypothermia has proven to be an effective neuroprotective strategy and has been implemented in clinical routine. Current studies are exploring various add-on therapies, including erythropoietin, xenon, topiramate, melatonin, and stem cells. This review aims to perform an updated integration of the pathophysiological processes after perinatal asphyxia in humans and animal models to allow us to answer some questions and provide an interim update on progress in this field.

Microbial Translocation and Perinatal Asphyxia/Hypoxia: A Systematic Review

The microbiome is vital for the proper function of the gastrointestinal tract (GIT) and the maintenance of overall wellbeing. Gut ischemia may lead to disruption of the intestinal mucosal barrier, resulting in bacterial translocation. In this systematic review, according to PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines, we constructed a search query using the PICOT (Patient, Intervention, Comparison, Outcome, Time) framework. Eligible studies reported in PubMed, up to April 2021 were selected, from which, 57 publications’ data were included. According to these, escape of intraluminal potentially harmful factors into the systemic circulation and their transmission to distant organs and tissues, in utero, at birth, or immediately after, can be caused by reduced blood oxygenation. Various factors are involved in this situation. The GIT is a target organ, with high sensitivity to ischemia–hypoxia, and even short periods of ischemia may cause significant local tissue damage. Fetal hypoxia and perinatal asphyxia reduce bowel motility, especially in preterm neonates. Despite the fact that microbiome arouse the interest of scientists in recent decades, the pathophysiologic patterns which mediate in perinatal hypoxia/asphyxia conditions and gut function have not yet been well understood.

Pharmacometric approach to assist dosage regimen design in neonates undergoing therapeutic hypothermia

BACKGROUND

Therapeutic hypothermia (TH) is the treatment of choice for neonates diagnosed with perinatal asphyxia (PA). Dosing recommendations of various therapeutic agents including antimicrobials were not specifically available for the neonates undergoing TH.

METHODS

A systematic search methodology was used to identify pharmacokinetic (PK) studies of antimicrobials during TH. Antimicrobials with multiple PK studies were identified to create a generalizable PK model. Pharmacometric simulations were performed using the PUMAS software platform to reproduce the results of published studies. A suitable model that could reproduce the results of all other published studies was identified. With the help of a generalizable model, an optimal dosage regimen was designed considering the important covariates of the identified model.

RESULTS

With the systematic search, only gentamicin had multiple PK reports during TH. A generalizable model was identified and the model predictions could match the reported/observed concentrations of publications. Birth weight and serum creatinine were the significant covariates influencing the PK of gentamicin in neonates. A dosage nomogram was designed using pharmacometric simulations to maintain gentamicin concentrations below 10 μg/mL at peak and below 2 μg/mL at trough.

CONCLUSIONS

A generalizable PK model for gentamicin during TH in neonates was identified. Using the model, a dosing nomogram for gentamicin was designed.

IMPACT

Dosing guidelines for antimicrobials during TH in neonates is lacking. This is the first study to identify the generalizable model for gentamicin during TH in neonates. Nomogram, proposed in the study, will aid the clinicians to individualize gentamicin dosing regimen for neonates considering the birth weight and serum creatinine.

Targeted temperature management after cardiac arrest is associated with reduced metabolism of pantoprazole - A probe drug of CYP2C19 metabolism

OBJECTIVE

Targeted temperature management (TTM) is part of standard post-resuscitation care. TTM may downregulate cytochrome enzyme activity and thus impact drug metabolism. This study compared the pharmacokinetics (PK) of pantoprazole, a probe drug of CYP2C19-dependent metabolism, at different stages of TTM following cardiac arrest.

METHODS

This prospective controlled study was performed at the Medical University of Vienna and enrolled 16 patients following cardiac arrest. The patients completed up to three study periods (each lasting 24 h) in which plasma concentrations of pantoprazole were quantified: (P1) hypothermia (33 °C) after admission, (P2) normothermia after rewarming (36 °C, intensive care), and (P3) normothermia during recovery (normal ward, control group). PK was analysed using non-compartmental analysis and nonlinear mixed-effects modelling.

RESULTS

16 patients completed periods P1 and P2; ten completed P3. The median half-life of pantoprazole was 2.4 h (quartiles: 1.8-4.8 h) in P1, 2.8 h (2.1-6.8 h, p = 0.046 vs. P1, p = 0.005 vs. P3) in P2 and 1.2 h (0.9 - 2.3 h, p = 0.007 vs. P1) in P3. A two-compartment model described the PK data best. Typical values for clearance were estimated separately for each study period, indicating 40% and 29% reductions during P1 and P2, respectively, compared to P3. The central volume of distribution was estimated separately for P2, indicating a 64% increase compared to P1 and P3.

CONCLUSION

CYP2C19-dependent drug metabolism is downregulated during TTM following cardiac arrest. These results may influence drug choice and dosing of similarly metabolized drugs and may be helpful for designing studies in similar clinical situations.

Neuroprotective strategies of cerebrolysin for the treatment of infants with neonatal hypoxic-ischemic encephalopathy

BACKGROUND

Perinatal asphyxia (PA) is a devastating neonatal condition characterized by a lack of oxygen supporting the organ systems. PA can lead to hypoxic-ischemic encephalopathy (HIE), a brain dysfunction due to oxygen deprivation with a complex neurological sequela. The pathophysiology of HIE and PA is not entirely understood, with therapeutic hypothermia being the standard treatment with only limited value. However, alternative neuroprotective therapies can be a potential treatment modality.

METHODS

In this review, we will characterize the biochemical mechanisms of PA and HIE, while also giving insight into cerebrolysin, a neuroprotective treatment used for HIE and PA.

RESULTS

We found that cerebrolysin has up to 6-month treatment window post-ischemic insult. Cerebrolysin injections of 0.1 ml/kg of body weight twice per week were found to provide gross motor and speech deficit improvement.

CONCLUSION

Our literature search emphasizes the positive effects of cerebrolysin for general improvement outcomes. Nevertheless, biomarker establishment is warranted to improve patient outcomes.

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.

Mitochondrial dysfunction in perinatal asphyxia: role in pathogenesis and potential therapeutic interventions

Perinatal asphyxia (PA)-induced brain injury may present as hypoxic-ischemic encephalopathy in the neonatal period, and long-term sequelae such as spastic motor deficits, intellectual disability, seizure disorders and learning disabilities. The brain injury is secondary to both the hypoxic-ischemic event and oxygenation-reperfusion following resuscitation. Following PA, a time-dependent progression of neuronal insult takes place in terms of transition of cell death from necrosis to apoptosis. This transition is the result of time-dependent progression of pathomechanisms which involve excitotoxicity, oxidative stress, and ultimately mitochondrial dysfunction in developing brain. More precisely mitochondrial respiration is suppressed and calcium signalling is dysregulated. Consequently, Bax-dependent mitochondrial permeabilization occurs leading to release of cytochrome c and activation of caspases leading to transition of cell death in developing brain. The therapeutic window lies within this transition process. At present, therapeutic hypothermia (TH) is the only clinical treatment available for treating moderate as well as severe asphyxia in new-born as it attenuates secondary loss of high-energy phosphates (ATP) (Solevåg et al. in Free Radic Biol Med 142:113-122, 2019; Gunn et al. in Pediatr Res 81:202-209, 2017), improving both short- and long-term outcomes. Mitoprotective therapies can offer a new avenue of intervention alone or in combination with therapeutic hypothermia for babies with birth asphyxia. This review will explore these mitochondrial pathways, and finally will summarize past and current efforts in targeting these pathways after PA, as a means of identifying new avenues of therapeutic intervention.

Exploring metabolic alterations associated with death from asphyxia and the differentiation of asphyxia from sudden cardiac death by GC-HRMS-based untargeted metabolomics

The determination of cause of death is one of the most important tasks in forensic practice. However, asphyxia is a difficult cause of death to determine, especially when the deceased has an underlying disease that can lead to a sudden unexpected death, such as coronary atherosclerotic heart disease (CAHD, which is the leading cause of sudden cardiac death, SCD), because its determination is currently still based on an exclusion strategy. In this study, gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS)-based untargeted metabolomics was employed to obtain the pulmonary metabolic profiles of rats who died from asphyxia and SCD. First, fourteen metabolites were identified to investigate the mechanism of death from asphyxia, and we proposed some explanations that may account for these metabolic alterations, including the perturbation of amino acid metabolism, lipid metabolism, and energy metabolism (TCA cycle). Second, we discovered eight potential biomarkers to differentiate between asphyxia and SCD as the cause of death. The excellent classification performances of the eight individual biomarkers and their combination in fresh lung tissue were observed. Third, we also explored the relative change in the concentration of the eight metabolites and their classification performance in decomposed tissue (at 24 h postmortem). Lactic acid, pantothenic acid, and the combination of the eight biomarkers can be recognized as perfect classifiers to discriminate asphyxia from SCD even when decomposition has occurred. Our results showed that GC-HRMS-based untargeted metabolomics can be used as a promising tool to explore the metabolic alterations of the death process and to determine the cause of death.

A Metabolomic Approach in Search of Neurobiomarkers of Perinatal Asphyxia: A Review of the Current Literature

Perinatal asphyxia and the possible sequelae of hypoxic-ischemic encephalopathy (HIE), are associated with high morbidity and mortality rates. The use of therapeutic hypothermia (TH) commencing within the first 6 h of life-currently the only treatment validated for the management of HIE-has been proven to reduce the mortality rate and disability seen at follow up at 18 months. Although there have been attempts to identify neurobiomarkers assessing the severity levels in HIE; none have been validated in clinical use to date, and the lack thereof limits the optimal treatment for these vulnerable infants. Metabolomics is a promising field of the "omics technologies" that may: identify neurobiomarkers, help improve diagnosis, identify patients prone to developing HIE, and potentially improve targeted neuroprotection interventions. This review focuses on the current evidence of metabolomics, a novel tool which may prove to be a useful in the diagnosis, management and treatment options for this multifactorial complex disease. Some of the most promising metabolites analyzed are the group of acylcarnitines: Hydroxybutyrylcarnitine (Malonylcarnitine) [C3-DC (C4-OH)], Tetradecanoylcarnitine [C14], L-Palmitoylcarnitine [C16], Hexadecenoylcarnitine [C16:1], Stearoylcarnitine [C18], and Oleoylcarnitine [C18:1]. A metabolomic "fingerprint" or "index," made up of 4 metabolites (succinate × glycerol/(β-hydroxybutyrate × O-phosphocholine)), seems promising in identifying neonates at risk of developing severe HIE.

A new microdialysis probe for continuous lactate measurement during fetal monitoring: Proof of concept in an animal model

INTRODUCTION

Cardiotocography (CTG) is currently the most commonly used method for intrapartum fetal monitoring during labor. However, a high false-positive rate of fetal acidosis indicated by CTG leads to an increase in obstetric interventions. We developed a microdialysis probe that is integrated into a fetal scalp electrode allowing continuous measurement of lactate subcutaneously, thus giving instant information about the oxygenation status of the fetus. Our aim was to establish proof of concept in an animal model using a microdialysis probe to monitor lactate subcutaneously.

MATERIAL AND METHODS

We performed an in vivo study in adult male wild-type Wistar rats. We modified electrodes used for CTG monitoring in human fetuses to incorporate a microdialysis membrane. Optimum flow rates for microdialysis were determined in vitro. For the in vivo experiment, a microdialysis probe was inserted into the skin on the back of the animal. De-oxygenation and acidosis were induced by lowering the inspiratory oxygen pressure. Oxygenation and heart rate were monitored. A jugular vein cannula was inserted to draw blood samples for analysis of lactate, pH, pco2 , and saturation. Lactate levels in dialysate were compared with plasma lactate levels.

RESULTS

Baseline blood lactate levels were around 1 mmol/L. Upon de-oxygenation, oxygen saturation fell to below 40% for 1 h and blood lactate levels increased 2.5-fold. Correlation of dialysate lactate levels with plasma lactate levels was 0.89 resulting in an R2 of .78 in the corresponding linear regression.

CONCLUSIONS

In this animal model, lactate levels in subcutaneous fluid collected by microdialysis closely reflected blood lactate levels upon transient de-oxygenation, indicating that our device is suitable for subcutaneous measurement of lactate. Microdialysis probe technology allows the measurement of multiple compounds in the dialysate, such as glucose, albumin, or inflammatory mediators, so this technique may offer the unique possibility to shed light on fetal physiology during the intrapartum period.

Preparation and characterization of lutein loaded folate conjugated polymeric nanoparticles

AIM

To prepare and characterise lutein-loaded polylactide-co-glycolide-polyethylene glycol-folate (PLGA-PEG-FOLATE) nanoparticles and evaluate enhanced uptake in SK-N-BE(2) cells.

METHODS

Nanoparticles were prepared using O/W emulsion solvent evaporation and characterised using DLS, SEM, DSC, FTIR and in-vitro release. Lutein-uptake in SK-N-BE(2) cells was determined using flow-cytometry, confocal-microscopy and HPLC. Control was lutein PLGA nanoparticles.

RESULTS

The size of lutein-loaded PLGA and PLGA-PEG-FOLATE nanoparticles were 189.6 ± 18.79 nm and 188.0 ± 4.06 nm, respectively. Lutein entrapment was ∼61%(w/w) and ∼73%(w/w) for PLGA and PLGA-PEG-FOLATE nanoparticles, respectively. DSC and FTIR confirmed encapsulation of lutein into nanoparticles. Cellular uptake studies showed ∼1.6 and ∼2-fold enhanced uptake of lutein from PLGA-PEG-FOLATE nanoparticles compared to PLGA nanoparticles and lutein, respectively. Cumulative release of lutein was higher in PLGA nanoparticles (100% (w/w) within 24 h) compared to PLGA-PEG-FOLATE nanoparticles (∼80% (w/w) in 48 h).

CONCLUSION

Lutein-loaded PLGA-PEG-FOLATE nanoparticles could be a potential treatment for hypoxic ischaemic encephalopathy.

Statistical differences resulting from selection of stable reference genes after hypoxia and hypothermia in the neonatal rat brain

Real-time reverse transcription PCR (qPCR) normalized to an internal reference gene (RG), is a frequently used method for quantifying gene expression changes in neuroscience. Although RG expression is assumed to be constant independent of physiological or experimental conditions, several studies have shown that commonly used RGs are not expressed stably. The use of unstable RGs has a profound effect on the conclusions drawn from studies on gene expression, and almost universally results in spurious estimation of target gene expression. Approaches aimed at selecting and validating RGs often make use of different statistical methods, which may lead to conflicting results. Based on published RG validation studies involving hypoxia the present study evaluates the expression of 5 candidate RGs (Actb, Pgk1, Sdha, Gapdh, Rnu6b) as a function of hypoxia exposure and hypothermic treatment in the neonatal rat cerebral cortex–in order to identify RGs that are stably expressed under these experimental conditions–using several statistical approaches that have been proposed to validate RGs. In doing so, we first analyzed RG ranking stability proposed by several widely used statistical methods and related tools, i.e. the Coefficient of Variation (CV) analysis, GeNorm, NormFinder, BestKeeper, and the ΔCt method. Using the Geometric mean rank, Pgk1 was identified as the most stable gene. Subsequently, we compared RG expression patterns between the various experimental groups. We found that these statistical methods, next to producing different rankings per se, all ranked RGs displaying significant differences in expression levels between groups as the most stable RG. As a consequence, when assessing the impact of RG selection on target gene expression quantification, substantial differences in target gene expression profiles were observed. Altogether, by assessing mRNA expression profiles within the neonatal rat brain cortex in hypoxia and hypothermia as a showcase, this study underlines the importance of further validating RGs for each individual experimental paradigm, considering the limitations of the statistical methods used for this aim.

Small molecule biomarkers for neonatal hypoxic ischemic encephalopathy

Hypoxic Ischemic Encephalopathy (HIE) is one of the most deleterious conditions in the perinatal period and the access to small molecule biomarkers aiding accurate diagnosis and disease staging, progress monitoring, and early outcome prognosis could provide relevant advances towards the development of personalized therapies. The emergence of metabolomics, the "omics" technology enabling the holistic study of small molecules, for biomarker discovery employing different analytical platforms, animal models and study populations has drastically increased the number and diversity of small molecules proposed as candidate biomarkers. However, the use of very few compounds has been implemented in clinical guidelines and authorized medical devices. In this work we review different approaches employed for discovering HIE-related small molecule biomarkers. Their role in associated biochemical disease mechanisms as well as the way towards their translation into the clinical practice are discussed.

Association between newborn screening analytes and hypoxic ischemic encephalopathy

Hypoxic ischemic encephalopathy (HIE) is a major cause of neonatal mortality and morbidity. Our study sought to examine whether patterns of newborn screening analytes differed between infants with and without neonatal HIE in order to identify opportunities for potential use of these analytes for diagnosis in routine clinical practice. We linked a population-based newborn screening registry with health databases to identify cases of HIE among term infants (≥37 weeks' gestation) in Ontario from 2010-2015. Correlations between HIE and screening analytes were examined using multivariable logistic regression models containing clinical factors and individual screening analytes (acyl-carnitines, amino acids, fetal-to-adult hemoglobin ratio, endocrine markers, and enzymes). Among 731,841 term infants, 3,010 were diagnosed with HIE during the neonatal period. Multivariable models indicated that clinical variables alone or in combination with hemoglobin values were not associated with HIE diagnosis. Although the model was improved after adding acyl-carnitines and amino acids, the ability of the model to identify infants with HIE was moderate. Our findings indicate that analytes associated with catabolic stress were altered in infants with HIE; however, future research is required to determine whether amino acid and acyl-carnitine profiles could hold clinical utility in the early diagnosis or clinical management of HIE. In particular, further research should examine whether cord blood analyses can be used to identify HIE within a clinically useful timeframe or to guide treatment and predict long-term health outcomes.

Temporal patterns of circulating cell-free DNA (cfDNA) in a newborn piglet model of perinatal asphyxia

Perinatal asphyxia is a severe medical condition resulting from oxygen deficiency (hypoxia) at the time of birth, causing worldwide approximately 680,000 newborn deaths every year. Better prediction of severity of damages including early biomarkers is highly demanded. Elevated levels of circulating cell-free DNA (cfDNA) in blood have been reported for a range of different diseases and conditions, including cancer and prematurity. The objective of this study was to validate methods for assessing cfDNA in blood and cerebrospinal fluid (CSF) and to explore temporal variations in a piglet model of neonatal hypoxia-reoxygenation. Different cfDNA extraction methods in combination with cfDNA detection systems were tested, including a fluorescent assay using SYBR Gold and a qRT-PCR-based technique. Newborn piglets (n = 55) were exposed to hypoxia-reoxygenation, hypoxia-reoxygenation and hypothermia, or were part of the sham-operated control group. Blood was sampled at baseline and at post-intervention, further at 30, 270, and 570 minutes after the end of hypoxia. Applying the fluorescent method, cfDNA concentration in piglets exposed to hypoxia (n = 32) increased from 36.8±27.6 ng/ml prior to hypoxia to a peak level of 61.5±54.9 ng/ml after the intervention and deceased to 32.3±19.1 ng/ml at 570 minutes of reoxygenation, whereas the group of sham-operated control animals (n = 11) revealed a balanced cfDNA profile. Animals exposed to hypoxia and additionally treated with hypothermia (n = 12) expressed a cfDNA concentration of 54.4±16.9 ng/ml at baseline, 39.2±26.9 ng/ml at the end of hypoxia, and of 41.1±34.2 ng/ml at 570 minutes post-intervention. Concentrations of cfDNA in the CSF of piglets exposed to hypoxia revealed at post-intervention higher levels in comparison to the controls. However, these observations were only tendencies and not significant. In a first methodological proof-of-principle study exploring cfDNA using a piglet model of hypoxia-reoxygenation variations in the temporal patterns suggest that cfDNA might be an early indicator for damages caused by perinatal asphyxia.

Prevalence and Associated Factors of Perinatal Asphyxia among Neonates in General Hospitals of Tigray, Ethiopia, 2018

Perinatal asphyxia is one of the most important causes of morbidity and mortality in neonates. Perinatal asphyxia occurs in association with maternal, fetal, and maternofetal factors. However, the magnitude and associated factors of perinatal asphyxia are not well studied in Tigray, Ethiopia. Therefore, our study is conducted to determine the prevalence and factors associated with perinatal asphyxia among neonates in general hospitals of Tigray. An observational hospital-based cross-sectional study was conducted in randomly selected general hospitals. A semistructured questionnaire was used to collect data from 421 randomly selected neonates with their mothers and medical records. The data was entered into epidata version 3.5 and exported to Statistical Package for Social Sciences (SPSS) version 20 for analysis. Finally, the presence of an association between a dependent variable and an independent variables has been declared at P-value ≤0.05, or adjusted odds ratio (AOR), 95% confidence interval (CI). Accordingly, the result of this study showed that the prevalence of perinatal asphyxia among the selected general hospitals was 22.1%. Neonates born with cesarean section are seven times more likely to have perinatal asphyxia than those who are born spontaneously through the vagina (AOR, 6.97; CI (2.87-16.93)). In addition, neonates who are born meconium stained are 8.55 times more likely to have perinatal asphyxia than those who had not stained with meconium (AOR, 8.55; CI (4.20-17.39)). Neonates who are weighed less than 2.5 kg are 12.75 times more likely to have perinatal asphyxia than those who are weighed 2.5-4 kg (AOR, 12.75; CI (4.05-40.08)). Prolonged duration of labour was also associated statistically with perinatal asphyxia (AOR, 3.33, CI (1.32-8.38)). In conclusion, the magnitude of perinatal asphyxia in general hospitals of Tigray remains high. Low birth weight, meconium-stained amniotic fluid, cesarean section, and prolonged maternal labour have been associated with perinatal asphyxia.

Gold nanorods/siRNA complex administration for knockdown of PARP-1: a potential treatment for perinatal asphyxia

Background

Perinatal asphyxia interferes with neonatal development, resulting in long-term deficits associated with systemic and neurological diseases. Despite the important role of poly (ADP-ribose) polymerase 1 (PARP-1) in the regulation of gene expression and DNA repair, overactivation of PARP-1 in asphyxia-exposed animals worsens the ATP-dependent energetic crisis. Inhibition of PARP-1 offers a therapeutic strategy for diminishing the effects of perinatal asphyxia.

Methods

We designed a nanosystem that incorporates a specific siRNA for PARP-1 knockdown. The siRNA was complexed with gold nanorods (AuNR) conjugated to the peptide CLPFFD for brain targeting.

Results

The siRNA was efficiently delivered into PC12 cells, resulting in gene silencing. The complex was administered intraperitoneally in vivo to asphyxia-exposed rat pups, and the ability of the AuNR-CLPFFD/siRNA complex to reach the brain was demonstrated.

Conclusion

The combination of a nanosystem for delivery and a specific siRNA for gene silencing resulted in effective inhibition of PARP-1 in vivo.

Neurological impairments in hypoxic neonates and lactate levels

INTRODUCTION

Metabolic acidosis with increasing lactate concentration develops due to the lack of oxygen in the tissues.

OBJECTIVES

The effect of lactic acidosis on neurological development in the first year of life.

MATERIALS AND METHODS

Our study included 50 newborns with perinatal hypoxia requiring oxygen therapy and 50 healthy newborns. pH, pCO2, pO2, base excess (BE) and lactates from arterialized capillary blood were determined in both groups of newborns, in the first and second hours after birth, and neurological development in the first year of life was estimated.

RESULTS

pH, pCO2, pO2, BE and lactates differed significantly between the groups in the first and second hours after birth p < 0.01. Hypotonia was recorded in 20/50 cases and hypertonia was recorded in 10/50 cases in the first year of life.

CONCLUSION

Lactate concentration may be an indicator of neurological damage in neonates with perinatal hypoxia.

A longitudinal 1H-NMR metabolomics analysis of urine from newborns with hypoxic-ischemic encephalopathy undergoing hypothermia therapy. Clinical and medical legal insights

Perinatal asphyxia is an event affecting around four million newborns worldwide. The 0.5 to 2 per 1000 of full term asphyxiated newborns suffer from hypoxic-ischemic encephalopathy (HIE), which is a frequent cause of death or severe disability and, as consequence, the most common birth injury claim for obstetrics, gynaecologists, and paediatricians. Perinatal asphyxia results from a compromised gas exchange that leads to hypoxemia, hypercapnia, and metabolic acidosis. In this work, we applied a metabolomics approach to investigate the metabolic profiles of urine samples collected from full term asphyxiated newborns with HIE undergoing therapeutic hypothermia (TH), with the aim of identifying a pattern of metabolites associated with HIE and to follow their modifications over time. Urine samples were collected from 10 HIE newborns at birth, during hypothermia (48 hours), at the end of the therapeutic treatment (72 hours), at 1 month of life, and compared with a matched control population of 16 healthy full term newborns. The metabolic profiles were investigated by 1H NMR spectroscopy coupled with multivariate statistical methods such as principal component analysis and orthogonal partial least square discriminant analysis. Multivariate analysis indicated significant differences between the urine samples of HIE and healthy newborns at birth. The altered metabolic patterns, mainly originated from the depletion of cellular energy and homeostasis, seem to constitute a characteristic of perinatal asphyxia. The HIE urine metabolome changes over time reflected either the effects of TH and the physiological growth of the newborns. Of interest, the urine metabolic profiles of the HIE non-surviving babies, characterized by the increased excretion of lactate, resulted significantly different from the rest of HIE population.

Surge of Peripheral Arginine Vasopressin in a Rat Model of Birth Asphyxia

Mammalian birth is accompanied by a period of obligatory asphyxia, which consists of hypoxia (drop in blood O₂ levels) and hypercapnia (elevation of blood CO₂ levels). Prolonged, complicated birth can extend the asphyxic period, leading to a pathophysiological situation, and in humans, to the diagnosis of clinical birth asphyxia, the main cause of hypoxic-ischemic encephalopathy (HIE). The neuroendocrine component of birth asphyxia, in particular the increase in circulating levels of arginine vasopressin (AVP), has been extensively studied in humans. Here we show for the first time that normal rat birth is also accompanied by an AVP surge, and that the fetal AVP surge is further enhanced in a model of birth asphyxia, based on exposing 6-day old rat pups to a gas mixture containing 4% O₂ and 20% CO₂ for 45 min. Instead of AVP, which is highly unstable with a short plasma half-life, we measured the levels of copeptin, the C-terminal part of prepro-AVP that is biochemically much more stable. In our animal model, the bulk of AVP/copeptin release occurred at the beginning of asphyxia (mean 7.8 nM after 15 min of asphyxia), but some release was still ongoing even 90 min after the end of the 45 min experimental asphyxia (mean 1.2 nM). Notably, the highest copeptin levels were measured after hypoxia alone (mean 14.1 nM at 45 min), whereas copeptin levels were low during hypercapnia alone (mean 2.7 nM at 45 min), indicating that the hypoxia component of asphyxia is responsible for the increase in AVP/copeptin release. Alternating the O₂ level between 5 and 9% (CO₂ at 20%) with 5 min intervals to mimic intermittent asphyxia during prolonged labor resulted in a slower but quantitatively similar rise in copeptin (peak of 8.3 nM at 30 min). Finally, we demonstrate that our rat model satisfies the standard acid-base criteria for birth asphyxia diagnosis, namely a drop in blood pH below 7.0 and the formation of a negative base excess exceeding -11.2 mmol/l. The mechanistic insights from our work validate the use of the present rodent model in preclinical work on birth asphyxia.

Plasma metabolite score correlates with Hypoxia time in a newly born piglet model for asphyxia

Hypoxic-ischemic encephalopathy (HIE) secondary to perinatal asphyxia is a leading cause of mortality and acquired long-term neurologic co-morbidities in the neonate. The most successful intervention for the treatment of moderate to severe HIE is moderate whole body hypothermia initiated within 6 h from birth. The objective and prompt identification of infants who are at risk of developing moderate to severe HIE in the critical first hours still remains a challenge. This work proposes a metabolite score calculated based on the relative intensities of three metabolites (choline, 6,8-dihydroxypurine and hypoxanthine) that showed maximum correlation with hypoxia time in a consolidated piglet model for neonatal hypoxia-ischemia. The metabolite score's performance as a biomarker for perinatal hypoxia and its usefulness for clinical grading and decision making have been assessed and compared to the performance of lactate which is currently considered the gold standard. For plasma samples withdrawn before and directly after a hypoxic insult, the metabolite score performed similar to lactate. However, it provided an enhanced predictive capacity at 2 h after resuscitation. The present study evidences the usefulness of the metabolite score for improving the early assessment of the severity of the hypoxic insult based on serial determinations in a minimally invasive biofluid. The applicability of the metabolite score for clinical diagnosis and patient stratification for hypothermia treatment has to be confirmed in multicenter trials involving newborns suffering from HIE.

Assessment of phospholipid synthesis related biomarkers for perinatal asphyxia: a piglet study

The prompt and reliable identification of infants at risk of hypoxic-ischemic encephalopathy secondary to perinatal asphyxia in the first critical hours is important for clinical decision-making and yet still remains a challenge. This work strives for the evaluation of a panel of metabolic biomarkers that have been associated with the hypoxic-ischemic insult in the perinatal period. Plasma and urine samples from a consolidated newborn piglet model of hypoxia and withdrawn before and at different time points after a hypoxic insult were analyzed and compared to a control group. Time-dependent metabolic biomarker profiles were studied and observed patterns were similar to those of lactate levels, which are currently considered the gold standard for assessing hypoxia. Class prediction performance could be improved by the use of a combination of the whole panel of determined metabolites in plasma as compared to lactate values. Using a multivariate model including lactate together with the studied metabolic biomarkers allowed to improve the prediction performance of duration of hypoxia time, which correlates with the degree of brain damage. The present study evidences the usefulness of choline and related metabolites for improving the early assessment of the severity of the hypoxic insult.

Urinary gas chromatography mass spectrometry metabolomics in asphyxiated newborns undergoing hypothermia: from the birth to the first month of life

BACKGROUND

Perinatal asphyxia is a severe clinical condition affecting around four million newborns worldwide. It consists of an impaired gas exchange leading to three biochemical components: hypoxemia, hypercapnia and metabolic acidosis.

METHODS

The aim of this longitudinal experimental study was to identify the urine metabolome of newborns with perinatal asphyxia and to follow changes in urine metabolic profile over time. Twelve babies with perinatal asphyxia were included in this study; three babies died on the eighth day of life. Total-body cooling for 72 hours was carried out in all the newborns. Urine samples were collected in each baby at birth, after 48 hours during hypothermia, after the end of the therapeutic treatment (72 hours), after 1 week of life, and finally after 1 month of life. Urine metabolome at birth was considered the reference against which to compare metabolic profiles in subsequent samples. Quantitative metabolic profiling in urine samples was measured by gas chromatography mass spectrometry (GC-MS). The statistical approach was conducted by using the multivariate analysis by means of principal component analysis (PCA) and orthogonal partial least square discriminant analysis (OPLS-DA). Pathway analysis was also performed.

RESULTS

The most important metabolites depicting each time collection point were identified and compared each other. At birth before starting therapeutic hypothermia (TH), urine metabolic profiles of the three babies died after 7 days of life were closely comparable each other and significantly different from those in survivors.

CONCLUSIONS

In conclusion, a plethora of data have been extracted by comparing the urine metabolome at birth with those observed at each time point collection. The modifications over time in metabolites composition and concentration, mainly originated from the depletion of cellular energy and homeostasis, seems to constitute a fingerprint of perinatal asphyxia.

Insights into the neuroprotective mechanisms of 2-iminobiotin employing an in-vitro model of hypoxic-ischemic cell injury

Several animal models have been used to simulate cerebral hypoxia-ischemia and suggested neuroprotective effects of the biotin analogue 2-iminobiotin (2-IB). The aims of this study were to employ a human in-vitro hypoxia model to confirm protective effects of 2-IB on neuronal cells, determine the optimal neuroprotective concentrations of 2-IB and scrutinize underlying cellular effects of 2-IB. Neuronal IMR-32 cells were exposed to hypoxia employing an enzymatic hypoxia system and were thereafter incubated with various concentrations of 2-IB (10 to 300ng/ml). Cell damage, metabolic activity and generation of reactive oxygen species were quantified using colorimetric/fluorometric lactate dehydrogenase (LDH), tetrazolium-based (MTS) and reactive oxygen species assays. Proteome profiling arrays were performed to evaluate the regulation of cell stress protein expression by hypoxia and 2-IB. Seven hours of hypoxia led to morphological changes in IMR-32 cultures, increased neuronal cell damage (P<0.001), reduction of metabolic activity (P<0.01) and enhanced reactive oxygen species production (P<0.05). Post-hypoxic application of 2-IB (30ng/ml) attenuated hypoxia-induced LDH release (P<0.05) and increased metabolic activity of IMR-32 cells (P<0.05), while reactive oxygen species production was only by trend decreased. Array-based protein expression profiling revealed that 2-IB attenuated the expression of several hypoxia-induced cell stress-associated proteins by more than 25% (pp38α, HIF2α, ADAMTS1, pHSP27, PON2, PON3 and p27). Hypoxia-induced neuronal cell damage can be simulated using the described in-vitro model. 2-IB inhibits hypoxia-mediated neurotoxicity most efficiently at 30ng/ml and the underlying mechanisms involve a downregulation of stress-associated protein expression. Our results suggest 2-IB as a potential drug for the treatment of perinatal hypoxia-ischemia.

Melatonin in the management of perinatal hypoxic-ischemic encephalopathy: light at the end of the tunnel?

Perinatal hypoxic-ischemic encephalopathy (HIE) affects one to three per 1,000 live full-term births and can lead to severe and permanent neuropsychological sequelae, such as cerebral palsy, epilepsy, mental retardation, and visual motor or visual perceptive dysfunction. Melatonin has begun to be contemplated as a good choice in order to diminish the neurological sequelae from hypoxic-ischemic brain injury. Melatonin emerges as a very interesting medication, because of its capacity to cross all physiological barriers extending to subcellular compartments and its safety and effectiveness. The purpose of this commentary is to detail the evidence on the use of melatonin as a neuroprotection agent. The pharmacologic aspects of the drug as well as its potential neuroprotective characteristics in human and animal studies are described in this study. Melatonin seems to be safe and beneficial in protecting neonatal brains from perinatal HIE. Larger randomized controlled trials in humans are required, to implement a long-awaited feasible treatment in order to avoid the dreaded sequelae of HIE.

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

BACKGROUND

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

POPULATION AND METHODS

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

RESULTS

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

CONTROL

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

CONCLUSIONS

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

Mapping the Knowledge Structure of Neonatal Hypoxic-Ischemic Encephalopathy Over the Past Decade: A Co-word Analysis Based on Keywords

The aim of this study was to analyze the knowledge structure and report the evolution of hypoxic-ischemic encephalopathy research over the past decade based on co-word analysis. Scientific publications focusing on neonatal hypoxic-ischemic encephalopathy were searched from the Web of Science database (January 2005 to December 2014). The keywords from these articles were extracted, and a knowledge network based on these keywords was built using Ucinet6.212 and NetDraw2.084 software. A total of 1892 papers were included, and 39 high-frequency keywords were defined. "HIE" and "neonate" located at the center of the knowledge network. Etiology and pathogenesis, clinical manifestation, and therapy were researched more widely in the network than other aspects of hypoxic-ischemic encephalopathy. This co-word analysis provides an overview of neonatal hypoxic-ischemic encephalopathy research and suggests that the etiology, clinical manifestation, and therapy of hypoxic-ischemic encephalopathy have become research cores over the past decade.

The choice of amniotic fluid in metabolomics for the monitoring of fetus health

Amniotic fluid (AF) is a biological fluid in which metabolite transport is regulated by the placenta, the permeable skin, fetal lung egress and gastric fluid. During pregnancy, the composition of AF changes from similar to the interstitial fluid of the mother, to a more complex system, influenced by the fetus's urine. Since AF reflects the mother's and the fetus's health status at the same time, it may be an important diagnostic tool for a wider spectrum of clinical conditions. Indeed, the metabolic characterization of AF in relation to pathological occurrences may lead to the discovery of new biomarkers for a better clinical practice. For this reason, metabolomics may be the most suitable strategy for this task. In this review, research works on metabolomic AF analysis are discussed according to the morbidity of interest, being preterm birth/labor, gestational age and diabetes and fetal malformations, along with a number of other important studies.

Metabolomics in Newborns

Metabolomics is the quantitative analysis of a large number of low molecular weight metabolites that are intermediate or final products of all the metabolic pathways in a living organism. Any metabolic profiles detectable in a human biological fluid are caused by the interaction between gene expression and the environment. The metabolomics approach offers the possibility to identify variations in metabolite profile that can be used to discriminate disease. This is particularly important for neonatal and pediatric studies especially for severe ill patient diagnosis and early identification. This property is of a great clinical importance in view of the newer definitions of health and disease. This review emphasizes the workflow of a typical metabolomics study and summarizes the latest results obtained in neonatal studies with particular interest in prematurity, intrauterine growth retardation, inborn errors of metabolism, perinatal asphyxia, sepsis, necrotizing enterocolitis, kidney disease, bronchopulmonary dysplasia, and cardiac malformation and dysfunction.